Major infectious diseases caused by biological

Diseases	Routes of transmission	Hidden period, days	Duration of disability, days
Plague	Airborne contact with a pulmonary patient; through flea bites, from large rodents		7-14
anthrax	Contact with large animals, their fur, skins; eating contaminated meat, inhaling infectious dust	2-3	7-14
Glanders	The same		20-30
Tularemia	Inhalation of dust, infectious pathogens; contact with sick rodents; drinking infectious water	3-6	40-60
Cholera	Drinking contaminated water and food		5-30
Yellow fever	Through mosquito bites, from sick animals and people	4-6	10-14
Smallpox	Airborne contact; through infectious objects		12-24
Spot fever rocky mountains	Through bites of tick vectors (from sick rodents)	4-8	90-180
Botulism	Eating food that contains toxins	0,5-1,5	40-80

Pathogenic microorganisms that cause intestinal infectious diseases can get into drinking water, milk, and food products, consuming which can cause a healthy person to get sick.

Distribution intestinal infections often contribute to flies, as well as contamination of hands with feces in people who do not adhere to the rules of their own hygiene.

Defeat healthy person occurs as a result of close contact with a patient, when infectious mucus particles easily penetrate the upper respiratory tract.

The mechanism of transmission of respiratory tract infection creates the possibility of its large epidemic spread, especially among children.

Among certain types of infections, influenza and measles are characterized by the fact that pathological processes develop at the site of pathogen penetration.

The fight against the spread of respiratory tract infections is carried out by isolating patients and using personal safety equipment (wearing gauze bandages that cover the nose and mouth of a sick person).

In the prevention of smallpox great importance have highly effective vaccinations (vaccinations and revaccinations).

This group includes anthrax, glanders, foot-and-mouth disease and other diseases. The infectious principle is transmitted from the source of infection directly and through contaminated objects: for example, a person can become infected with anthrax through a fur collar contaminated with anthrax bacteria, and a typical anthrax forms on the skin of the neck or face.

The main methods of combating infections of the external integument are the isolation and treatment of patients, as well as breaking the transmission routes of infection, for example, making shoes only from raw materials that have been tested for contamination with anthrax spores.

To prevent the above infections, there is vaccination prevention.

Zone (focus) of biological contamination. Quarantine, observation

As a result of the release of hazardous biological agents into the environment (accident, cases of introduction of a pathogen, use of biological weapons) and spread in the area pathogenic microbes, toxins, dangerous pests, may form zones of biological contamination and the focus of biological damage.

Biological contamination zone– this is an area contaminated with biological pathogens of diseases dangerous to people, animals or plants.

The causative agents of infectious diseases can spread, increasing the area of ​​infection, by people, insects, especially blood-borne ones, animals, rodents, and birds. People, farm animals, poultry, wild animals and birds, air, terrain, reservoirs, wells, reservoirs with drinking water, fodder, agricultural crops, crop supplies, food, machinery, pastures and living quarters.

The infection zone is characterized by:

Species biological protection;

Dimensions;

Placement relative to the ONH;

The time of education;

Degree of danger;

Changing time.

The size of the focus of biological contamination depends on:

Type, species, number of pathogenic microbes and plant pests;

Conditions for exposure and reproduction in the environment;

Meteorological conditions;

The speed of their detection;

Timely implementation of preventive and therapeutic measures.

Site of biological damage This is a territory in which, as a result of the influence of biological properties, mass destruction of people, farm animals, and plants occurred.

It is characterized by:

Types of biological properties;

The number of affected people, plants, animals;

Duration of actions;

Damaging properties of pathogens.

If a focus of biological infection occurs, to prevent the spread of infections from the focus, it is introduced quarantine and observation.

Quarantine- this is a system of government measures that are carried out in an epidemiological (epizootic, epiphytotic) focus to prevent the spread of infectious diseases from the lesion for complete isolation and its elimination. Quarantine provides for the isolation of the team among whom infectious diseases have arisen with the hospitalization of patients, observation of those who were in contact with them, and medical and veterinary observation of the rest.

For this purpose, the following administrative, economic, anti-epidemic, veterinary, sanitary, sanitary and hygienic, anti-epidemic, treatment and preventive measures are carried out:

1. Complete isolation of the lesion:

A guard is posted around the fire, a commandant service is organized, and traffic patrols are organized.

All farms bordering the source of biological contamination are notified of the establishment of quarantine. When pathogens are detected, especially dangerous diseases(anthrax, glanders, plague, foot and mouth disease, rinderpest, African plague pigs and other diseases) areas adjacent to the source of infection are declared a threatened zone. On all land waterways at the border crossing, 24-hour quarantine posts are set up, and patrols are organized between them. Checkpoints are set up on main routes of communication - highways, railways, waterways, at places where they intersect with the border of the affected zone, as well as at airports in the quarantine zone. Warning signs indicating detours and detours are installed on all roads leading to the outbreak.

2.B populated areas and an internal curfew service is organized at the facilities, protection of infectious disease isolation centers and hospitals, control points, etc. is provided.

3. The exit of people, animals and property from quarantine areas is prohibited. Transport to the contaminated territory is permitted by the head of the Civil Defense only for specialized units on their transport.

4.Transit passage of vehicles through the affected areas is prohibited (railway transport may be an exception).

5. Business entities that continue their activities switch to a special mode of operation with strict compliance epidemiological activities. Work shifts are divided into small groups, and contact between them is reduced to a minimum. Meals and rest for workers and employees are organized in groups in specially allocated rooms. Everyone's work stops educational institutions, entertainment events, markets and bazaars.

6.The population in the quarantine zone is divided into small groups, the so-called quarantine. He is not allowed to leave his houses or apartments unless absolutely necessary. Food, water and basic necessities are delivered by special teams. If it is necessary to perform urgent work outside the home, people must wear personal protective equipment.

7. The work of shops, workshops, and household establishments can be resumed only after the type of pathogen has been established and the epidemiological situation has been established. In this case, strict security measures will not be required immediately after disinfection of the environment and sanitization of the population.

In the complex of anti-epizootic measures at the source of infection, the following are important:

Clinical and laboratory examination of animals and their separation into groups;

Measures to eliminate exposure during external environment– disinfection of the area, transport, livestock and other premises and adjacent areas, water, food, fodder and animal care items;

Conducting veterinary reconnaissance, summarizing and analyzing its results;

Preventive and compulsory vaccinations;

Veterinary treatment and treatment of sick and suspected animals;

Examination and disinfection of meat and other raw products from animals that have been exposed to biological properties;

Bringing slaughter stations and sites into proper condition and deploying them again;

Equipment for cattle burial grounds and corpse disposal sites;

Control over the use of meat and milk from affected animals;

Control over the removal of corpses and their burial.

In the outbreak of individual diseases, all workers and employees of enterprises and institutions must take personal safety measures:

Wear protective masks;

Adhere to basic rules of personal hygiene at work and at home;

Do not consume untested food and water;

Light a fire in the contaminated area;

If signs of illness appear, contact medical authorities;

The population in the outbreak of infectious diseases carries out:

Disinfection of your apartments;

Disinfection of water and food;

Washable at home;

Changes clothes;

Monitors your well-being and minor illness(fever, cold, diarrhea) immediately calls a doctor by phone, through the attached sanitary squad or the sanitary officer for the building.

Under quarantine conditions the following is provided:

Carrying out emergency prevention;

Strengthening epidemiological surveillance;

For the population: - door-to-door visits; early detection; isolation and hospitalization of infectious patients; enhanced medical control over the implementation of sanitary and hygienic measures; sanitization and disinfection; and preventive vaccinations.

Such treatment is organized medical staff, attached to objects of economic activity.

Each sanitary squad is assigned a part of the street, block, building or workshop, which the sanitary squads walk around 2-3 times a day. The population, workers and employees, are issued medicinal preparations. For prophylaxis, broad-spectrum antibiotics and other drugs are used that provide preventive and healing effect. The population that has AI-2 first-aid kits carries out preventive treatment with the help of drugs from the first-aid kit.

Quarantine is organized by decision of the state administration and the executive committee of the district or region. Quarantine measures are fully carried out only in the event of the appearance of particularly dangerous diseases and those that are characterized by rapid and massive infection (plague, typhoid, cholera, smallpox, foot-and-mouth disease, anthrax, glanders).

In cases where the identified type of pathogen does not belong to the group of particularly dangerous infectious diseases and there is no threat of mass diseases, the introduced quarantine is replaced observation. Under observation understand the implementation of a number of isolation-restrictive and therapeutic measures in the affected area preventive measures aimed at preventing the spread of infectious diseases.

Regime measures in the observation zone, as opposed to quarantine, include:

Maximum restrictions on entry and exit, as well as removal of property from the outbreak without prior disinfection and permission from epidemiologists;

Strengthening medical control over food and water supply;

Restriction of movement in the contaminated area, communication between separate groups of people;

Other events.

When establishing an observation regime, it is necessary to find out:

Number of affected animals;

Carry out veterinary treatment of animals with simultaneous disinfection of places where animals are placed and all objects that come into contact with them.

In this case, set:

Veterinary observation of affected animals;

They are prohibited from grazing in areas of infection;

Limit contact with them;

Organize the departure from the source of infection and entry into its territory of all types of transport, the movement and transportation of animals, the passage of livestock and crop products through the observation zone;

Conduct biological control of contamination of farm animals, livestock products, water and feed.

To prevent infectious diseases, the same treatment and preventive measures are carried out as during quarantine, but in observation conditions, isolation and preventive measures are less strict, i.e., the exit of the population from the infection zone is not prohibited, but is limited and allowed, subject to mandatory carrying out preventive measures.

Less often, communication contact between the population in the middle of the outbreak is limited.

The regime and rules of behavior established in the outbreak of infectious diseases, as well as the requirements of the medical service, must be followed by all citizens. No one has the right to avoid preventive vaccinations or taking medications.

To prevent massive expansion, strictly follow the rules of personal hygiene:

In residential buildings, it is necessary to disinfect entrance handrails, door handles, toilets - fill them with bleach, clean the premises using a wet method, and prevent the breeding of flies and mosquitoes.

In areas of infectious diseases, take water from the water supply or from uninfected tested medical service water sources.

All products should be stored in closed containers and processed before use:

Boil water and milk;

Rinse raw vegetables and fruits thoroughly;

Eating using individual utensils.

Before leaving the premises:

Put on individual means respiratory and skin protection;

Before entering residential premises from the street, shoes and raincoats must be left outside the premises and then treated with disinfectants. Special attention refer patients for examination.

All precautions must be taken if the patient remains at home: it is better to place him in a separate room. If this is not possible, cover it with a screen.

In the room, disinfect and disinfect objects that the patient has touched. Disinfection can be carried out in the simplest ways: washing them with soap, boiling individual items, etc.

One person must provide care at all times. This requires compliance with safety rules and personal hygiene rules.

To disinfect premises, a settled solution of 0.1-0.5% bleach is most often used. To prepare a 5% solution, you need to dissolve 0.5 kg of bleach in 10 liters of water and allow the solution to settle.

Quarantine or observation can also occur in peacetime in cases of dangerous diseases in areas or regions. However, it is of a rather weakened nature (regime) depending on the disease (the paramilitary forces of the Civil Defense are not used).

It is possible to declare a quarantine of local importance (schools, kindergartens, etc.) without restrictions and isolation of territories without the use of paramilitary service, etc., using the medical resources of the city or district.

In quarantine and observation zones, from the very beginning of their formation, disinfection (disinfection), disinfection and deratization (extermination of insects and rodents) measures are carried out. The terms of quarantine and observation are established based on the duration of the maximum incubation period in the hearth infectious disease(taking into account the hospitalization of the last infectious patient and the end of the final disinfection).

The problem of choosing a system of units of physical quantities until recently could not be entirely related to our arbitrariness. From the point of view of materialist philosophy, it was not easy for us to convince anyone that a large section of the natural sciences related to ensuring the unity of measurements is fundamentally based on the dependence of the main points on our consciousness. It is possible to discuss whether the system of units is well or poorly designed physical units, but the fact that basically any system of quantities and units has arbitrariness associated with human consciousness remains indisputable.

Units of physical quantities are divided into basic and derivative. Until 1995, there were still additional units - units of plane and solid angles, radians and steradians - but in order to simplify the system, these units were transferred to the category of dimensionless derived units.

Basic physical quantities are quantities chosen arbitrarily and independently of each other.

Basic units are chosen so that, using the natural relationship between quantities, it would be possible to form units of other quantities. Accordingly, quantities and units formed in this way are called derivatives.

Most main question when constructing systems of units is how many basic units should there be or, more precisely, what principles should be followed when constructing a particular system? Partially in the metrological literature one can find the statement that the main principle of the system should be a minimum number of basic units. In fact, this approach is incorrect, since following this principle there can be only one such quantity and unit. For example, almost any physical quantity can be expressed through energy, since in mechanics energy is equal to:

• kinetic energy

where m is mass, -v is the speed of movement of the body;

• potential energy

(1.4)

where m is mass, g is acceleration, H is height (length).

In electrical measurements, charge energy

(1.5)

where q is the charge, U is the potential difference.

In optics and quantum mechanics, photon energy

where h is Planck's constant, v is the radiation frequency.

In thermophysics, the energy of thermal motion of particles

(1.7)

where k is Boltzmann's constant, T is temperature.

Using these laws and relying on the law of conservation of energy, it is possible to determine any physical quantity, regardless of what phenomena it relates to - mechanical, electrical, optical or thermal.

To make what has been said more convincing, let us consider the basic mechanical units adopted in most systems - units of length, time and mass. These quantities are basic, i.e., chosen arbitrarily and independently of each other. Let us now consider what is the degree of this independence and whether it is possible to reduce the number of arbitrarily chosen basic mechanical units.

Most of us are accustomed to the fact that Newton's second law is written as

(1.8)

where F is the interaction force, m is the mass of the body, and is the acceleration of movement, and this expression is the definition of inertial mass. On the other hand, gravitational mass according to the law of universal gravitation is determined from the relation

(1.9)

where r is the distance between bodies and γ is the gravitational constant, equal to

(1.10)

Considering, for example, the uniform motion of one body around another in a circle, when the inertial force Fi is equal to the gravitational force Fg, and taking into account that the mass m in both laws is the same quantity, we obtain:

(1.11)

(1.12)

where T is the period of revolution, we get

(1.13)

This is an expression for Keppler's third law, long known for motion celestial bodies, i.e. we received the connection between time T, length r and mass m in the form

(1.14)

This means that it is enough to set the coefficient K equal to unity, and the unit of mass will be determined through length and time. The value of this coefficient

(1.15)

is a consequence only of the fact that we arbitrarily chose a unit of mass and, in order to bring the situation into compliance with physical laws, we are obliged to introduce an additional factor K in Keppler’s law. The above example clearly shows that the number of basic units can be changed either smaller or larger side, i.e. it completely depends on our choice, determined by the convenience of practical use of the system.

Naturally, having arbitrarily chosen any unit as the main one, we arbitrarily choose the size of this unit. In mechanical measurements, we have the opportunity to compare length, time and mass with any quantities of the same name chosen as initial ones. As metrology developed, the definitions of the size of the quantities of the basic units changed repeatedly, however, this did not affect either the physical laws or the unity of measurements.

Let us show that the arbitrariness of the choice of unit size occurs not only for basic, arbitrarily chosen quantities, but also for derivative quantities, i.e., those associated with some basic physical law. As an example, let us return to the definitions of force through the inertial properties of bodies or through gravitational properties. We assume that the main quantities are length, time and mass. Nothing prevents us from considering the coefficient of proportionality in the law of universal gravitation to be equal to unity, i.e., from considering that

(1.16)

Then in Newton’s second law we will be required to introduce a proportionality coefficient called the inertial constant, i.e.

(1.17)

The value of the inertial constant must be equal to

(1.18)

A similar picture can be traced by expressing and taking the unit of area. We are accustomed to the fact that the unit of area is the area of ​​a square with a side of one unit of length - a square meter, a square centimeter, etc. However, no one forbids choosing the area of ​​a circle with a diameter of 1 meter as a unit of area, i.e., counting What

(1.19)

In this case, the area of ​​the square will be expressed

(1.20)

This unit of area, called the “round meter,” is very convenient in measuring the areas of circles. Obviously, a “round meter” will be 4/π times smaller than a “square meter”.

The next question in the problem of choosing system units is to determine the advisability of introducing new basic units when considering a new class of physical phenomena. Let's start with electromagnetic phenomena. It is well known that electrical phenomena are based on Coulomb’s law, which connects mechanical quantities - the force of interaction and the distance between charges - with an electrical quantity - charge:

(1.21)

In Coulomb's law, as in other laws where vector quantities are mentioned, we omit the unit vectorfor the purpose of simplification. In Coulomb's law, the proportionality coefficient is equal to 1. If we take this as a basis, which is done in some systems of units, then the electrical basic unit is not needed, since the unit of current can be obtained from the relation

(1.22)

where q is the charge determined by Coulomb's law; t - time. All other units of electrical quantities are determined from the laws of electrostatics and electrodynamics. Nevertheless, in most systems of units, including the SI system, an electrical base unit is arbitrarily introduced for electrical phenomena. In the SI system this is Ampere. Having chosen Ampere arbitrarily, the charge will be expressed from the relationship as

(1.23)

As a result, the situation discussed above was repeated, when the same physical quantity is determined twice. Once through mechanical quantities - formula (1.21) and another time through Ampere formula (1.23). This ambiguity forces us to introduce an additional coefficient into Coulomb’s law, called the “dielectric constant of vacuum.” Coulomb's law takes the form:

ABOUT physical sense dielectric constant of vacuum are often asked questions when they want to find out the degree of understanding of the essence of Coulomb's law. From a metrological point of view, everything is simple and clear: by arbitrarily introducing the basic unit of electricity - the ampere - we must take measures to ensure that there is a correspondence between the mechanical units introduced earlier and their new possible expression using the ampere.

Exactly the same situation can be traced in temperature measurements with the introduction of an arbitrary basic unit - Kelvin, as well as in optical measurements with the introduction of candela.

Here we consider in detail the situation with the choice of units of basic physical quantities and with the choice of their size in order to prove the essence of the main principle of constructing systems of units of physical units.

This principle is ease of practical use. Only these considerations determine the number of basic units, the choice of their size, and all additional, secondary principles are based on this as the main one. This, for example, is the well-known principle that states that as a basic quantity one must choose one whose unit can be reproduced with the highest possible accuracy. However, this is desirable, but in some cases it is impractical. In particular, in mechanical measurements, the unit of frequency - the hertz - is reproduced with the highest accuracy, however, frequency is not included in the category of basic units.

In electrical measurements, more precisely, the Ampere can be reproduced by the Volt - a unit of potential difference. In optics, extreme precision has been achieved in energy measurements by counting quanta. For these reasons, the generally accepted expression of quantities and units becomes dominant over the desire to choose as the basic unit the one that is most accurately reproduced.

The final confirmation of the choice of a unit system based on the principle of usability is two points.

The first is the fact of the presence in the international SI system of two basic units of quantity of a substance - the kilogram and the mole. Nothing but ease of use chemical processes the introduction of another basic unit - the mole - this fact cannot be explained.

The second is the fact that in a number of cases systems of units other than the SI system are used. For many years and decades, metrologists have been trying to maintain one single system of units. However, the SI system is inconvenient for calculating atomic and molecular structures, and people continue to use the atomic system of units, in which the basic quantities are determined by the size of the atom and the processes occurring in the atom. When considering various systems of units, we will dwell in detail on the construction of this system. In the same way, the SI system turns out to be inconvenient when measuring distances to space objects. This area has developed its own specific system of units and quantities.

the choice in metrology of a system of units of physical quantities is mainly related to the convenience of their use and is largely based on traditions in solving the problem of ensuring the uniformity of measurements.

Lecture 1

Introductory lesson. Subject "metrology", tasks, principles, objects and means of metrology, standardization and certification. Law of the Russian Federation “On ensuring the uniformity of measurements”. International metrology organizations.

Word metrology formed from two Greek words metron(measure) and logo(teaching, skill) and means the teaching of measures. Metrology in the modern sense is the science of measurements, methods and means of ensuring their unity and ways of achieving the required accuracy.

Unity of measurements is the state of measurements in which their results are expressed in legal units and the errors are known with a given probability.

For a long time metrology was primarily a descriptive science of various measures and the relationships between them. But in the process of development of society, the role of measurements increased, and since the end of the last century, thanks to the progress of physics, metrology has risen to a qualitatively new level.

Today, metrology is not only the science of measurements, but also an activity that involves the study of physical quantities, their reproduction and transmission, the use of standards, the basic principles and methods of creating measuring instruments, the assessment of their errors, as well as metrological control and supervision.

The purpose of metrology is to ensure the uniformity of measurements, i.e. comparability and consistency of their results, regardless of where, when and by whom these results were obtained.

Since critical decisions are made based on measurement results, appropriate accuracy, reliability and timeliness of measurements must be ensured.

There are three main functions measurements in the national economy:

1) product accounting National economy, calculated by mass, length, volume, consumption, power, energy;

2) measurements carried out to control and regulate technological processes and to ensure the normal functioning of transport and communications;

3) measurements of physical quantities, technical parameters, composition and properties of substances, carried out at scientific research, testing and control of products in various sectors of the national economy.

The significance of measurements is especially important during the transition to market relations associated with competition among manufacturers and, accordingly, with increased requirements for the quality and technical parameters of products. Improving the quality of measurements and introducing new measurement methods depend on the level of development of metrology.

The main objectives of metrology are;

· ensuring research, production and operation of technical devices;

· control over the state of the environment;

· providing institutions and organizations with appropriate measuring instruments.

Metrology is divided into

· general - theoretical and experimental;

· applied (practical);

· legislative.

Theoretical metrology deals with issues of fundamental research, the creation of a system of units of measurement, physical constants, and the development of new measurement methods.

Experimental metrology- issues of creating standards, sample measures, development of new measuring instruments, devices and information systems.

Applied (practical) metrology deals with practical application of results in various fields of activity theoretical research within the framework of metrology.

Legal metrology includes a set of interrelated and interdependent general rules, as well as other issues, regulation and control of which are necessary on the part of the state and to ensure the uniformity of measurements and the uniformity of the measurement system.

Metrological service- a set of subjects of activity and types of work aimed at ensuring the uniformity of measurements.

The law specifies that State Metrological Service is under the jurisdiction of the State Standard of Russia and includes: state scientific metrological centers; bodies of the State Metrological Service on the territory of the republics of the Russian Federation, autonomous region, autonomous districts, territories, regions, cities of Moscow and St. Petersburg.

Gosstandart of Russia manages the State Service for Time and Frequency and Determination of Earth Rotation Parameters (GSVCh), the State Service for Standard Samples of the Composition and Properties of Substances and Materials (GSSO) and the State Service for Standard Reference Data on Physical Constants and Properties of Substances and Materials (GSSSD) and coordinates their activities.

The objects of state supervision are:

1. normative documents on standardization and technical documentation;

2. products, processes and services;

3. other objects in accordance with the current legislation on state supervision.

In 1993, the “Law of the Russian Federation on ensuring the uniformity of measurements” was adopted, which establishes the legal basis for ensuring the uniformity of measurements in the Russian Federation. The law regulates the relations of government bodies of the Russian Federation with legal entities and individuals on the issues of manufacturing, production, operation, repair, sale and import of measuring instruments and is aimed at protecting the rights and legitimate interests of citizens, the established legal order and the economy of the Russian Federation from the negative consequences of unreliable measurement results .

The Law “On Ensuring the Uniformity of Measurements” consists of seven sections: general provisions; units of quantities, means and techniques for performing measurements; metrological services; state metrological control and supervision; calibration and certification of measuring instruments; responsibility for violation of the law and financing of work to ensure the uniformity of measurements.

In the first section, the Law “On Ensuring the Uniformity of Measurements” establishes and legislates the basic concepts adopted for the purposes of the Law: uniformity of measurements, measuring instrument, state standard of a unit of magnitude, regulatory documents to ensure the uniformity of measurements, metrological service, metrological control and supervision, verification and calibration of measuring instruments, certificate of type approval of measuring instruments, accreditation for the right to verify measuring instruments and calibration certificate. The first article of the law gives the following definition of the concept of “unity of measurements”.

uniformity of measurements- a state of measurements in which their results are expressed in legal units of quantities and the measurement errors do not go beyond the established limits with a given probability.

The concept of “uniformity of measurements” covers the most important tasks metrology: unification of units, development of systems for reproducing units and transferring their sizes to working measuring instruments With established accuracy, carrying out measurements with an error not exceeding established limits, etc. The uniformity of measurements must be maintained at any measurement accuracy required by the economic sector.

Ensuring uniformity of measurements is task of metrological services.

The complex of regulatory, normative, technical and methodological documents at the intersectoral level, establishing rules, norms, requirements aimed at achieving and maintaining the uniformity of measurements in the country with the required accuracy, is state system for ensuring the uniformity of measurements(GSI).

The GSI identifies basic standards that establish general requirements, rules and regulations, as well as standards covering a specific area or type of measurement.

Fundamental basic standards include, for example, GOST 8.417 “GSI. Units of physical quantities", GOST 16363 "Metrology. Terms and definitions." Basic standards can be divided into groups depending on the object of standardization:

· standards of units of physical quantities;

· transfer of information about the unit size from standards to measuring instruments;

· the procedure for standardizing the metrological characteristics of measuring instruments;

· rules for performing and recording measurement results;

· uniformity of measuring instruments;

· metrological supervision over the development, condition and use of measuring instruments;

· public service of standard reference data.

Currently, the GS I regulatory framework contains more than 2,600 documents, including 388 GOSTs, about 2,000 guidelines from metrological institutes, 77 guidance documents and 87 instructions.

The network of organizations that are responsible for metrological support of measurements constitutes the metrological service. There are two levels of metrological service - the state metrological service and the metrological services of legal entities (enterprises and associations).

The civil service includes territorial bodies and state scientific metrological centers (Research Institute of Gosstandart of Russia). The structure of the state metrological service also includes specialized services: the state service of time and frequency - GSVCH, the state service of standard samples - GSSO, the state service of standard reference data - GSSSD.

The main types of metrological activities include metrological support for production preparation, state testing of measuring instruments, and verification of measuring instruments.

Metrological support for production preparation- this is a set of organizational and technical measures aimed at determining with the required accuracy the parameters of products (products, components, materials) and raw materials, technological processes and equipment and allowing to achieve high quality of products, as well as reduce unproductive costs for their production.

Work on metrological support for production preparation is carried out by metrological, design, and technological services of enterprises from the moment they receive the initial documents for the product being mastered.

Testing of measuring instruments is carried out by state scientific centers of the State Standard of Russia.

The commission includes representatives:

· State center for testing measuring instruments;

· customer of measuring instruments;

· departmental metrological service;

· development organization;

· manufacturer of measuring instruments.

In case of successful testing of the measuring instrument, as a result of which all parameters and characteristics of the measuring instrument are confirmed, the documentation is submitted to Gosstandart of Russia and a decision is made to approve the type of measuring instrument. This decision is certified by a certificate of approval of the type of measuring instruments. The approved type is entered into the state register of measuring instruments.

State metrological control and supervision is technical and legal activities carried out by the bodies of the state metrological service in order to verify compliance with the rules of legal metrology - the Law of the Russian Federation “On ensuring the uniformity of measurements”, regulations on metrology issues.

The objects of state metrological control and supervision include:

· measuring instruments;

· standards used for verification of measuring instruments;

· measurement techniques;

· the number of packaged goods in packages of any type during their sale and packaging.

State metrological control (SMC) applies to:

1. for healthcare, veterinary medicine, environmental protection, safety;

2. trade transactions and mutual settlements between buyer and seller;

3. state accounting operations;

4. ensuring defense;

5. geodetic and hydrometeorological works;

6. banking, tax, customs and postal operations;

7. products supplied under government contracts;

8. testing and quality control of products for compliance with mandatory requirements of standards and when mandatory certification products;

9. measurements carried out on behalf of the court, prosecutor's office, arbitration, and other government bodies;

10. registration of national and international sports records.

Characteristic types of government metrological control and supervision.State metrological control and supervision includes:

1. state metrological supervision over the quantity of goods alienated during trade operations; the quantity of packaged goods in packages of any type during their packaging and sale;

2. verification of measuring instruments, including standards;

3. approval of the type of measuring instruments;

licensing of activities of legal entities and individuals for the manufacture, repair, sale, rental of measuring instruments. Trade operations are subject to state metrological control, during which the mass, volume, consumption and other quantities characterizing the quantity of goods being alienated are determined.

Measuring instruments for identification are subject to state metrological supervision in the field of banking operations valuable papers and currencies (for example, currency detectors, banknote counters), electronic signatures, collateral values. When accepting valuables such as precious metals and precious stones for deposit, banks must ensure that their quantity and composition are measured with the required accuracy.

Packaged goods in packages of any type are subject to state metrological supervision during their sale or packaging, in cases where the contents of the package cannot be changed without opening or deforming it, and the amount of contents is indicated by the mass value printed on the package. When conducting supervision, the compliance of the actual value of mass, volume and other quantities with the amount actually contained in the packaging of the goods and the value printed on the packaging is checked.

Measuring instruments used in the specified areas of state metrological control and supervision are subject to verification by state metrological service bodies upon release and after repair, during operation and sale, and importation. Verification of measuring instruments is carried out by persons certified as verifiers in the bodies of the state metrological service. Positive results of verification of measuring instruments are certified by a verification mark or a verification certificate. The verification mark is applied to measuring instruments and operational documentation, and in the case of issuing a verification certificate - to the certificate. If the verification mark is damaged, as well as if the certificate is lost, the measuring instrument is considered unsuitable for use.

Measuring instruments intended for production or import are subject to mandatory testing with subsequent type approval. The decision to approve the type of measuring instrument is made by Gosstandart of Russia and is certified by a certificate. The approved type is entered into the State Register of Measuring Instruments. IN necessary cases The type of measuring instrument is also subject to mandatory certification for safety of use in accordance with the legislation on the protection of health, life and property of citizens, labor protection and the environment.

Organization of state metrological control and supervision. Control and supervision are carried out by state inspectors of the state metrological service. State inspectors freely visit facilities where measuring instruments are used in order to verify them, take samples of goods to carry out control during their sale and packaging, and other types of control. If a violation is detected, the state inspector has the right to prohibit the use of measuring instruments of unapproved and unverified types; extinguish stamps or cancel the verification certificate in cases where the measuring instrument gives incorrect readings or the verification interval has expired; give mandatory instructions and set deadlines for eliminating violations of metrological rules; draw up protocols on the administrative responsibility of violators of metrological rules to make decisions on the application of sanctions.

Legal entities and individuals are obliged to assist the inspector in fulfilling his duties. Persons who interfere with the implementation of state metrological control and supervision are liable in accordance with current legislation.

In accordance with the current legislation, administrative and criminal liability and economic sanctions are provided for violation of the rules of legal metrology.

Administrative liability for violation of the rules lies with managers and officials of legal entities, as well as individuals through whose fault the violations were committed. Administrative penalties are imposed in the form of a fine. The basis for the penalty is failure to comply with metrology rules when selling and packaging goods, failure to comply with the rules for verification of measuring instruments, and obstruction of metrological control and supervision by authorized bodies.

Criminal liability arises in the event of the use of unverified or other unsuitable measuring instruments in a retail trade network or in the field of public catering, healthcare, environmental protection, and security. Depending on the degree of violation of metrological rules, a large fine, correctional labor, deprivation of the right to hold positions related to measurement, and imprisonment are provided. Economic sanctions are applied, as a rule, to legal entities. The amount of sanctions is determined by current legislation.

	Composition of the State Metrological Service of the Russian Federation (SMS).
	Name of institution	Functions of the institution
	Federal Agency for Technical Regulation and Metrology - heads the State Migration Service	Development, discussion, approval and accounting of technical regulations, national standards, all-Russian classifiers, cataloging systems, etc. Management_coordination of activities of the State Migration Service. Conducting competitions for awards from the Government of the Russian Federation.
	State scientific metrological centers (SSMC) -7VNII	Storing state standards, conducting research; development of high-precision measurement methods and regulatory documents
	Regional centers for standardization, metrology and certification (TSSM and C) - more	State control and supervision of ensuring the uniformity of measurements in the region, metrological support of enterprises, verification and calibration of measuring instruments, accreditation of measuring laboratories, training and certification of verifiers, development of new measuring instruments, maintenance and repair.
	State Service for Time, Frequency and Determination of Earth Rotation Parameters (GSHF)	Interregional and intersectoral coordination of work in this area, storage and transmission of unit sizes of time and frequency, coordinates of the earth's poles. Measurement information is used by navigation and control services for ships, aircraft and satellites, etc.
	State Service for Standard Samples of Composition and Properties of Materials (GSSO)	Provide the development of means for comparing standard samples with the characteristics of substances and materials produced by industrial and agricultural enterprises for their identification and control.
	State Service of Standard Reference Data on Physical Constants and Properties of Substances and Materials (GSSSD)	They ensure the development of reliable data on physical constants, properties of substances, oil, gas, etc. The information is used by organizations that create new equipment.

International metrology organizations
Name of company	Goals, objectives and activities of the organization
1. International Organization of Legal Metrology (OILM)	Created in 1955. Unites more than 80 states. Goals: development general issues legal metrology, incl. establishing SI accuracy classes, ensuring uniformity in defining types and samples of SI systems, recommendations for testing and training. Supreme body international Conference legal metrology. Convened once every 4 years. Decisions are advisory in nature. Russia is represented in the OIML by the Federal Agency for Technical Regulation and Metrology, as well as 12 ministries and departments. Russia’s participation allows us to influence the content of adopted recommendations, ensuring their compliance Russian standards, allows you to improve metrological work.
2. International Organization of Weights and Measures (IOMW)	Created in 1875 - the Metrological Convention was signed. Goals: unification of national units of measurement and establishment of common actual standards of length and mass. The BIPM is a research laboratory that stores and maintains international standards. ITS main task is to compare national standards with international ones and improve measurement systems. The highest body of the IOMB is the General Conference of Weights and Measures. (once every 4 years). The work of the IOMV between conferences is led by the International Committee of Weights and Measures, which includes the world's leading physicists and metrologists, incl. representatives of Russia. There are 18 members in total. The most important result of the activity is the transition of countries to common units and standards.
3. International Organization for Standardization (ISO)	Created in 1946. ISO members are national standardization organizations around the world. 135 countries are represented. ISO's scope of activity extends to all fields except electrical and electronics engineering. Main objectives: development of standardization, metrology and certification in order to ensure the exchange of goods and services, development of cooperation in scientific, technical and economic fields. ISO standards are the most widely used in the world, their total number exceeds 12,000. About 1,000 standards are adopted and revised annually. They are not mandatory for use by ISO member countries. Everything depends on the degree of participation of the country in the international division of labor and the state of its foreign trade. It's on in Russia active process implementation of ISO standards national system standardization.
4. International Electrotechnical Commission (IEC)	Created in 1906. An autonomous organization within ISO. The main goal is defined by the Charter - promoting international cooperation in standardization in the field of electrical and radio engineering through the development of standards. Countries are represented in the IEC by their national authorities
	standardization (RF - Federal Agency for Technical Regulation and Metrology). The highest governing body of the IEC is the Council of National Committees of all countries. The IEC has adopted more than 2000 standards. They are more specific than ISO standards and therefore more suitable for use in IEC member countries. More than half of the standards adopted by the IEC have been implemented in Russia.
European Organization for Metrology (EUROMET)	Regional international organization. Works in the field of research and development of national standards, promotes the development of verification services, and develops methods of the highest accuracy.

International organization weights and measures(IIOM) ensures the storage and maintenance of international standards of various units and comparison of state standards with them and consists of the General Conference of Weights and Measures, the International Committee on Weights and Measures, and the International Bureau of Weights and Measures (BIPM).

In most countries of the world, measures to ensure the uniformity of measurements are established by law. Therefore, one of the branches of metrology is called legal metrology and includes a set of general rules, requirements and norms aimed at ensuring the uniformity of measurements and uniformity of measuring instruments. For uniformity in units of measurement, in 1978 it was approved International standard“Units of physical quantities” (SI), which was introduced on January 1, 1979 as mandatory in all areas of the national economy, science, technology and teaching.

Basic concepts and definitions accepted in metrology. Physical quantities. Types of scales. Concepts about the system of physical quantities.

Basic terms and definitions are formulated in a number of regulatory and technical documents.

Physical quantity- a property of a physical object, phenomenon or process that is common in qualitative terms for many physical objects, but in quantitative terms is individual for each of them, for example, length, mass, electrical resistance.

Measurement- a set of application operations technical means, which stores a unit of physical quantity, consisting in comparing the measured quantity with the unit.

Measuring range- range of values ​​of quantities within which the permissible error limits are normalized. Values ​​that limit the measurement range from below or above (left or right) are called the lower limit or upper limit of measurements.

Sensitivity threshold- the smallest value of the measured quantity that causes a noticeable change in the output signal. For example, if the sensitivity threshold of the scale is $Q mi» to, this means that a noticeable movement of the scale needle is achieved with such a small change in mass as 10 mg.

MEASUREMENT SCALES

Measurement scale is an ordered set of values ​​of a physical quantity that serves as the basis for measuring a given quantity. Ordering the values ​​of a physical quantity can be achieved in different ways.

Name scale characterized only by the relation of equivalence of various qualitative manifestations of a property. These scales do not have a zero mark, units of measurement, they do not have comparison relations such as more, less, better, worse, etc. For example, in a color scale, the measurement process is achieved by determining equivalence by visual observation of the test sample with one of the standards included in the color atlas.

The simplest way to obtain information that allows you to get some idea of ​​the size of the measured value is to compare it with another according to the principle “which is larger (smaller)?”, or “which is better (worse)?”.

In this case, the number of sizes compared with each other can be quite large. Arranged in ascending or descending order, the sizes of the measured quantities form order scales.

The operation of arranging sizes in ascending or descending order in order to obtain measurement information on an order scale is called ranking . To facilitate measurements on the order scale, some points on it can be fixed as supporting (reference) ones. Scale points can be assigned numbers, often called points. For example, knowledge is assessed on a four-point reference scale, which has the following form: unsatisfactory, satisfactory, good, excellent. The hardness of minerals, the sensitivity of films and other quantities are measured using reference scales (the intensity of earthquakes is measured on a 12-point scale called the international seismic scale).

Interval scale (differences) describes the properties of a quantity not only using equivalence relations, but also using the summation and proportionality of intervals between quantitative manifestations of the property. An example is the time scale, which is divided into large intervals - years, into smaller ones - days, etc.

Using the interval scale, you can judge not only whether one size is larger than another, but also how much larger. However, the interval scale cannot estimate how many times one size is larger than another. This is due to the fact that on an interval scale only the scale is known, and the origin can be chosen arbitrarily.

The most perfect is relationship scale. An example of this is the Kelvin temperature scale, the Celsius scale, mass scales, etc.

Using the ratio scale, you can determine not only how much one size is larger than another, but also how many times larger or smaller.

PHYSICAL QUANTITIES

Main object measurements in metrology are physical quantities. A physical quantity is used to describe material systems, objects, phenomena, processes studied in any sciences. There are basic and derived quantities. The main ones are the quantities that characterize the fundamental properties of the material world. GOST 8.417 establishes seven basic physical quantities: length, mass, time, thermodynamic temperature, amount of substance, luminous intensity, current. The measured quantities have quantitative and qualitative characteristics.

A formalized reflection of the qualitative difference between measured quantities is their dimension. In accordance with ISO documents, dimension is indicated by the symbol dim (from the Latin dimension - measurement).

The dimensions of basic physical quantities - length, mass, time - are indicated by the corresponding capital letters:

dim t= T.

The dimension of a physical quantity is written as a product of the symbols of the corresponding basic physical quantities raised to a certain power - the dimension indicator:

Where L, M, T- dimensions of basic physical quantities;

Dimensional indices (indicators of the power to which the dimensions of basic physical quantities are raised).

For example: acceleration dimension - m/s 2

Each dimension indicator can be positive or negative, integer or fractional, zero. If all dimension indicators are equal to zero, then the quantity is called dimensionless.

The quantitative characteristic of the measured quantity is its size. Obtaining information about the size of a physical quantity is the content of any measurement.

Measured value- an estimate of the size of a physical quantity in the form of a certain number of units accepted for it.

For example: L= 1 m = 100 cm = 1000 mm.

The abstract number included in it is called numerical value. In the example given it is 1, 100, 1000.

The value of a physical quantity is obtained as a result of its measurement or calculation in accordance with the basic measurement equation:

where Q is the value of a physical quantity;

X- numerical value of the measured quantity in the accepted unit; [Q] - unit selected for measurement.

Let's say the length of a straight line segment of 10 cm is measured using a ruler with divisions in centimeters and millimeters. For this case:

At the same time, the use of different units (1 cm and 1 mm) led to a change in the numerical value of the measurement result.

Construction principles International system units. Advantages of SI.

Unit of physical quantity is a physical quantity that, by definition, is assigned a numerical value equal to one (1 m, 1 pound, 1 cm). System of units of physical quantities- a set of basic and derived units related to a certain system of quantities and formed in accordance with accepted principles.

In Russia, as in almost all countries of the world, the International System of Units operates, the main physical quantities of which are the meter, kilogram, second, ampere, candela, kelvin, and mole. The international system was approved in 1960 at the XI Conference of Weights and Measures.

Units of physical quantities of the international system of physical quantities are formed on the basis of laws establishing the relationship between physical quantities, or on the basis of physical quantities adopted in certain research institutes.

For uniformity in units of measurement, the International Standard “Units of Physical Quantities” (SI) was approved in 1978, which was introduced on January 1, 1979 as mandatory in all areas of the national economy, science, technology and teaching.

The SI contains seven basic units that cover measurements of all kinds of parameters: mechanical, thermal, electrical, magnetic, light, acoustic and ionizing radiation and in the field of chemistry. The basic units are: meter (m) - for measuring length; kilogram (kg) - to measure mass; second (s) - to measure time; ampere (A) - to measure the strength of electric current; Kelvin (K) - for measuring temperature; candela (candle) cd - to measure the intensity of light, mole - to measure the amount of substance.

Until 1960, the international standard and national standard of length 1 m was taken to be the distance between the centers of two lines on an X-shaped block made of an alloy of platinum and iridium. For this standard, the distance between the centers of the strokes could not be measured more accurately than ±0.1 µm, which did not meet the requirements current state science and technology. The disadvantage of the standard was that it was a metal block, which in the event of a natural disaster (for example, an earthquake or flood) could disappear or lose the exact value of the meter over time.

Principles of construction of the International System of Units

The first system of units of physical quantities, although it was not yet a system of units in the modern sense, was adopted by the French National Assembly in 1791. It included units of length, area, volume, capacity and mass, the main of which were two units: the meter and kilogram.

The system of units as a set of basic and derived units was first proposed in 1832 by the German scientist K. Gauss. He built a system of units, based on the units of length (millimeter), mass (milligram) and time (second), and called it the absolute system

Unit of length(meter)- the length of the path traveled by light in a vacuum in 1/299,792,458 of a second.

Unit of mass(kilogram)- mass equal to the mass of the international prototype of the kilogram.

When constructing systems of units of physical quantities, two stages are distinguished: Stage 1 - selection of basic units; Stage 2 - formation of derivative units.

The sequence of arrangement of derived units must satisfy the following conditions:

the first must be a quantity that is expressed only through basic quantities;

each subsequent one must be a quantity that is expressed only through the basic and such derivatives that precede it. For example, the following sequence of units: area, volume, density.

The main principle when constructing a system of units is the ease of use of units in science, industry, and trade. In this case, they are guided by a number of rules: the simplicity of the formation of derivative units, the high accuracy of reproduction of basic and derivative units and the proximity of their sizes to the sizes of physical quantities most often encountered in practical activities. In addition, they always try to keep the number of basic units to a minimum.

Examples of systems of units of physical quantities

Gauss system. The millimeter, milligram, and second were chosen as the basic units and a system of magnetic quantities was constructed. The system was called absolute. In 1851, Weber extended it to the field of electrical quantities. Currently it is of only historical interest, because... units are too small. However, the principle discovered by Gauss underlies the construction of modern systems of units - this is the division into basic and derivative units.

The GHS system was adopted in 1881 with the base units centimeter, gram, second. This system is convenient for physical research. Based on it, seven systems of electrical and magnetic quantities arose. Currently, the GHS system is used in theoretical sections of physics and astronomy.

The natural system of units is based on physical constants. The first such system was proposed in 1906 by Planck. The main units chosen were: the speed of light in vacuum, the gravitational constant, Boltzmann and Planck constants. The advantage of these systems is that when constructing physical theories they give physical laws a simpler form and some formulas are freed from numerical coefficients. However, the units of physical quantities have a size that is inconvenient for practice. For example, the unit of length in this system is equal to 4.03 10-35 m. In addition, such precision in the measurement of the selected universal constants has not yet been achieved so that all derived units can be established.

Relative and logarithmic quantities and units

Relative and logarithmic quantities are widely used in science and technology, because they characterize the composition and properties of materials, the relationship of energy quantities, for example, relative density, relative dielectric constant, power amplification and attenuation.

A relative quantity is a dimensionless ratio of a physical quantity to a physical quantity of the same name, taken as the original one. For example, the atomic and molecular masses of chemical elements relative to 1/12 the mass of a carbon-12 atom. Relative values ​​can be expressed in dimensionless units, in percent, ppm (the ratio is 10-3), in ppm.

A logarithmic quantity is the logarithm of the dimensionless ratio of two physical quantities of the same name. They are used, for example, to express sound pressure level, gain, attenuation, etc.

The unit of the logarithmic value is bel (B): 1 B = log (P2 / P1) with P2 = 10P1, where P2 and P1 are the same values ​​of power, energy, etc. For the ratio of two quantities of the same name associated with force (tension, pressure, etc.), bel is determined by the formula:

1B = 2 log (F2/F1) with F2 = 100.5 F1.

The submultiple unit of bel is the decibel, equal to 0.1 B.

International System of Units (SI)

The development of science and technology increasingly demanded the unification of units of measurement. Required one system units, convenient for practical use and covering various areas of measurement. In addition, it had to be coherent. Since the metric system of measures was widely used in Europe since the beginning of the 19th century, it was taken as the basis during the transition to a unified international system of units.

In 1960, the XI General Conference on Weights and Measures approved the International System of Units of Physical Quantities (Russian designation SI, international SI) based on six basic units. The decision was made:

• - assign the name “International System of Units” to the system based on six basic units;
• - establish an international abbreviation for the name of the SI system;
• - enter a table of prefixes for the formation of multiples and submultiples;
• - create 27 derived units, indicating that other derived units can be added.

In 1971, a seventh base unit of quantity of matter (the mole) was added to the SI.

When constructing the SI, we proceeded from the following basic principles:

• - the system is based on basic units that are independent of each other;
• - derived units are formed using the simplest communication equations and only one SI unit is established for each type of quantity;
• - the system is coherent;
• - along with SI units, non-system units widely used in practice are allowed;
• - the system includes decimal multiples and submultiples.

Advantages of SI:

• - versatility, because it covers all measurement areas;
• - unification of units for all types of measurements - the use of one unit for a given physical quantity, for example, for pressure, work, energy;
• - SI units are convenient in size for practical use;
• - switching to it increases the level of measurement accuracy, because the basic units of this system can be reproduced more accurately than those of other systems;
• - This is a unified international system and its units are widespread.

In the USSR, the International System (SI) was introduced by GOST 8.417-81. As SI continued to develop, the class of supplementary units was removed from it, a new definition of the meter was introduced, and a number of other changes were introduced. Currently, the Russian Federation has an interstate standard GOST 8.417-2002, which establishes the units of physical quantities used in the country. The standard states that they are subject to mandatory application SI units, as well as decimal multiples and submultiples of these units.

Derived SI units are formed according to the rules for the formation of coherent derived units (see example above). Examples of such units and derived units that have special names and designations are given. 21 derived units were given names and designations after the names of scientists, for example, hertz, newton, pascal, becquerel.

A separate section of the standard lists units that are not included in SI. These include:

• 1. Non-system units allowed for use along with SI because of their practical importance. They are divided into areas of application. For example, in all areas the units used are ton, hour, minute, day, liter; in optics diopter, in physics electron-volt, etc.
• 2. Some relative and logarithmic quantities and their units. For example, percent, ppm, white.
• 3. Non-system units temporarily allowed for use. For example, nautical mile, carat (0.2 g), knot, bar.

A separate section provides rules for writing unit symbols, using unit symbols in the headings of table graphs, etc.

The appendices to the standard contain rules for the formation of coherent derived SI units, a table of relationships between some non-systemic units and SI units, and recommendations for the selection of decimal multiples and submultiples.

Units whose names include the names of the main units. Examples: unit of area - square meter, dimension L2, unit designation m2; unit of flux of ionizing particles - second to the minus first power, dimension T-1, unit designation s-1.

Units with special names. Examples:

force, weight - newton, dimension LMT-2, unit designation N (international N); energy, work, amount of heat - joule, dimension L2MT-2, designation J (J).

Units whose names are formed using special names. Examples:

moment of force - name newton meter, dimension L2MT-2, designation Nm (Nm); specific energy - name joule per kilogram, dimension L2T-2, designation J/kg (J/kg).

Decimal multiples and submultiples are formed using factors and prefixes, from 1024 (yotta) to 10-24 (yocto).

Attaching two or more prefixes in a row to a name is not allowed, for example, not a kilogram, but a ton, which is a non-systemic unit allowed along with the SI.

Due to the fact that the name of the basic unit of mass contains the prefix kilo, to form submultiple and multiple units of mass, the submultiple unit gram is used and prefixes are attached to the word “gram” - milligram, microgram.

The choice of a multiple or submultiple unit of the SI unit is dictated primarily by the convenience of its use, and the numerical values ​​of the obtained quantities must be acceptable in practice. It is believed that numerical values ​​of quantities are most easily perceived in the range from 0.1 to 1000.

In some areas of activity, the same submultiple or multiple unit is always used, for example, in mechanical engineering drawings, dimensions are always expressed in millimeters.

To reduce the likelihood of errors in calculations, it is recommended to substitute decimal and multiple submultiple units only in the final result, and during the calculation process, express all quantities in SI units, replacing prefixes with powers of 10.

GOST 8.417-2002 provides rules for writing unit designations, the main ones of which are the following.

Units should be designated by letters or symbols, and two types of letter designations are established: international and Russian. International designations are written in relationships with foreign countries(contracts, supply of products and documentation). When used on the territory of the Russian Federation, Russian designations are used. At the same time, only international designations are used on plates, scales and shields of measuring instruments.

The names of units are written with a small letter unless they appear at the beginning of a sentence. The exception is degrees Celsius.

In unit designations, a dot is not used as an abbreviation sign; they are printed in roman font. Exceptions are abbreviations of words that are included in the name of a unit, but are not themselves names of units. For example, mm Hg. Art.

Unit designations are used after numeric values ​​and placed on the line with them (without moving to the next line). Between last digit and the designation should leave a space, except for the sign raised above the line.

When indicating the values ​​of quantities with maximum deviations, the numerical values ​​should be enclosed in brackets and unit designations should be placed after the brackets or placed both after the numerical value of the quantity and after its maximum deviation.

The letter designations of the units included in the product should be separated by dots on the middle line, like multiplication signs. It is allowed to separate letter designations with spaces if this does not lead to misunderstanding. Geometric dimensions are indicated by the sign “x”.

In letter symbols for the ratio of units, only one line should be used as a division sign: oblique or horizontal. It is allowed to use unit designations in the form of a product of unit designations raised to powers.

When using a slash, the unit symbols in the numerator and denominator should be placed on the same line, and the product of the unit symbols in the denominator should be enclosed in parentheses.

When indicating a derived unit consisting of two or more units, it is not allowed to combine letter designations and names of units, i.e. for some they are designations, for others they are names.

The designations of units whose names are derived from the names of scientists are written with a capital letter.

It is allowed to use unit designations in explanations of quantity designations for formulas. Placing unit symbols on the same line with formulas expressing the relationships between quantities and their numerical values, presented in letter form, is not allowed.

The standard identifies units by areas of knowledge in physics and indicates the recommended multiples and submultiples. There are 9 areas of use of units:

• 1. space and time;
• 2. periodic and related phenomena;
• 3. mechanics;
• 4. warmth;
• 5. electricity and magnetism;
• 6. light and associated electromagnetic radiation;
• 7. acoustics;
• 8. physical chemistry and molecular physics;
• 9. ionizing radiation.