Story. What is a magnet and why is it needed?

It is difficult to find a person who does not know what a magnet is. More precisely, a certain metal-like piece can attract various iron objects to itself, and also be mutually attracted or mutually repelled from another similar magnet. But nature itself similar phenomena Not everyone knows. Although the essence of the magnet is not hidden in itself special secrets and difficulties. Everything about it is quite simple. Let's look in this article at the reason and nature that underlies the operation of a magnet.

So, first of all, let's start with the following. I think you have heard that the basis of the work of any electrical appliances is the movement of electric current through the internal circuits of the device. Electric current is small electrical particles, having a certain electric charge and orderly moving inside conductors (everything that conducts current through itself) when such an opportunity arises (when a closed circuit arises). Particles with negative charge are usually called electrons. They are the ones in solids do their work (movement). In liquid and gaseous substances ions with a positive charge move.

What is the connection between electrically charged particles and magnets that expresses its essence? And the connection is direct! Scientists have long established that a magnetic field arises precisely around a moving electric charge. You may also have heard that magnetic fields exist around ordinary wires through which current flows. As soon as the current stops moving, the electromagnetic field also disappears. This is the essence and condition of occurrence magnetic field.

From school physics it is known that any things and objects around us consist of atoms and molecules (fairly small elementary particles). These are the same elementary particles, in turn, have the following structure. Inside there is a nucleus (consisting of protons and neutrons) (the nucleus has a positive charge), and around this nucleus with enormous speed Smaller particles rotate, these are electrons (having a negative charge).

So, the essence of a magnet is as follows. Since we have found out that a magnetic field arises around moving electric charges, and electrons are in all atoms and molecules, and they are constantly moving, therefore atoms and molecules have magnetic fields around them (they are very small in both strength and size). In addition, it is worth considering that various substances and objects have different magnetic properties. Some have very strong magnetic properties, while others have such weak magnetic properties that they indicate complete absence fields.

This is the basis of the nature and essence of a magnet. But even those substances that have a high intensity of magnetic fields (these are ferromagnets, the most famous of which is simple iron) are not always magnetic. Why is this so? Because there is an effect of unidirectionality and chaos. Let me explain what it is. The essence of a magnet (manifestation of magnetism) depends not only on the substance, but also on the position of atoms and molecules that exists inside the substance. If two magnets are connected in such a way that their poles coincide in direction, then the magnetic force of the fields will strengthen each other and the resulting total field will become stronger. But if these magnets are placed with opposite poles relative to each other, naturally, they will oppress each other, and their common field will weaken. Likewise, inside substances, in order to obtain the greatest magnetic field, it is necessary that all atoms and molecules magnetic substance were unidirectional with their poles. This is achieved in various ways.

And so, we figured out the very essence of the magnet and its nature of action. Now a little about how magnets are made. If you need to make a permanent magnet (an ordinary piece of magnet that permanently magnetizes), take a material from a ferromagnet, place it in a magnetic field of sufficiently high intensity for certain time. After which this ferromagnet itself begins to have magnetic properties. As a result of placing it in a high-intensity magnetic field, the elementary particles of the substance turned in one direction, which gave rise to the effect of unidirectionality of atoms and molecules.

To produce electromagnets, I use simple copper coils, inside of which a ferromagnetic core is placed, which enhances the overall magnetic effect. That is, when they pass through this coil D.C. she begins to attract iron objects to herself. After all, current flows through the coil (charged particles). Consequently, an electromagnetic field will arise around it. And the more turns there are on the coil and the more current passes through it, the greater the magnetic force will be generated around it.

P.S. So, in principle, we have figured out the nature and essence of a magnet. Knowing general principle The structure and operation of a magnet (electromagnet) Now it is all clear to you why magnets attract iron objects to themselves.

TASS DOSSIER. On February 16, 2018, at the Russian Investment Forum in Sochi, the founder, CEO and main owner of the Russian retail chain Magnit, Sergei Galitsky, entered into an agreement with VTB to sell the bank a controlling stake in the retailer - 29.1% of shares - for 138 billion rubles.

It is expected that in the near future the post of general director of Magnit will be taken by the chairman of the board of directors Khachatur Pombukhchan.

"Magnet" is one of largest companies retail trade in Russia and Europe. As of the beginning of 2018, there were 16 thousand 350 stores under the management and brand of Magnit, including 243 hypermarkets. In total, the company operates in 2 thousand 665 cities of Russia. Most stores are opened in the Southern, North Caucasian, Volga and Central federal districts. The company has one of the largest transport and logistics networks in Russia. "Magnit" ranks 1st among Russian retailers in terms of revenue (according to the company "InfoLine-Analytics") and 7th place in Russia among all Russian companies (according to the RBC-500 rating). Registered in Krasnodar.

Story

The founder of the company is entrepreneur Sergei Galitsky. In July 1995, together with his partner Alexei Bogachev, he created the Thunder company (now Joint-Stock Company, JSC "Tander") and became her general director. Initially the company was engaged wholesale supplies perfumes in southern regions Russia. In 1998, the company opened the first retail supermarket "Magnit" in Krasnodar. Subsequently, stores were created in other cities, mainly in the south of Russia. Galitsky avoided competition with large retail chains, developing business in small towns and positioning his outlets like convenience stores with low prices. In the early 2000s, they were united into a retail chain called Magnit.

In 2003, Galitsky registered Magnit OJSC (now PJSC), which received 100% of Tander shares.

In 2006, Magnit listed its shares on the stock exchange, and with the proceeds the construction of the chain's hypermarkets began. Since 2010, the company has been developing a network of Magnit-Cosmetics retail stores. In its stores "Magnit" sells a range of products own brands: “Family Secrets”, “Master Shine”, “North Harbor”, “Saving Smart”, “ Trading house Smetanin" and others.

Indicators

Based on the results of the last reporting year 2016, Magnit’s consolidated revenue for international standards financial statements amounted to 1 trillion 74 billion rubles. (an increase of 4.6% compared to 2015), net profit amounted to 1.14 billion rubles. (Before this, Magnit showed a net loss for the last three years).

According to Spark-Interfax, Magnit accounts for 25% of the revenue of all retail trade in the Russian Federation and 22% of the revenue of all companies registered in the Krasnodar Territory.

Management

Since 2006, Sergei Galitsky has been the general director of Magnit, and since 2010, also the chairman of the board. Chairman of the Board of Directors - Khachatur Pombukhchan.

Owners

At the end of the third quarter of 2017, Galitsky owned 35.11% of the company’s shares. The largest minority shareholder is the American investment company OppenheimerFunds Inc. More than 50% of the retailer's shares are traded on the open market. Current market capitalization is about $10 billion.

Section 1. Russian retail company "Magnit".

« Magnet» is a Russian retail company and food store chain of the same name ( most of of which are in the “convenience store” format. As of mid-2012, it is the largest in the country in terms of the number of food stores commercial network. One of the five largest retailers in the world by capitalization. The parent organization of the network is Closed Joint Stock Company (JSC) “Tander”. The headquarters is in the city of Krasnodar. One of the few retail chains not equipped with payment terminals.

Russian retail company " Magnet»

Firm dates its history back to 1994, when its current owner Sergei Galitsky founded organization for trade in household chemicals. The very first Magnit store was opened in 1998 in Krasnodar at the address st. Tyulyaeva, 8. The retail network developed rapidly, reaching 1,500 stores by the end of 2005. Since 2006, the development of a network of hypermarkets began.

At the end of December 2008, the Magnit network was included in the list of companies that will receive government support during the crisis.

Foundation of the organization sale household chemicals S.N. Galitsky

Tander becomes one of the leading official distributors of household chemicals and cosmetics in Russian Federation

The decision was made to enter the food retail trade

1998 - 1999: Entry into retail market food

Opening of the first grocery store in Krasnodar

Experimenting with format

The stores are united into the Magnit retail chain

2001 - 2005: Intensive development with the aim of taking a strong position in market

Swift regional development: 1,500 stores at the end of 2005

Adoption of IFRS

Motivational remuneration system

2006 - 2009: Further development traditional format. Transition to multi-format

Leader of Russian food retail by number of customers

In 2006

Hypermarkets

An independent director was elected to the Board of Directors

An Audit Committee was established

A set of rules of corporate conduct has been developed and introduced

SPO in 2008, 2009

24 hypermarkets opened in 2007-2009

636 convenience stores opened in 2009 (total number of stores as of December 31, 2009 is 3,228)

2010-2012: Strong position in the sector

Accelerated growth - more than 1,000 convenience stores, 42 hypermarkets and 208 cosmetics stores opened in 2011

Successful placement of shares in December 2011, proceeds amounted to $475 million.

Large-scale investment program for 2012: capital plan expenses in the amount of about 1.1-1.4 billion dollars.

Planned opening of up to 800 convenience stores and 50-55 hypermarkets during 2012

Working to improve efficiency

The Magnit chain of stores is:

Market leader in the number of retail facilities and their coverage area in the Russian Federation - 64 branches, 1 representative office, more than 5,268 convenience stores and 98 hypermarkets, 5 Family Magnit stores and 351 cosmetics stores in more than 1,461 cities and locality. Currently, several dozen stores are opening per month;

More than 140,000 employees who, through their work, provide customers with the opportunity to purchase high-quality everyday goods at affordable prices;

The latest methods and technologies in the field of product distribution, sales, finance and personnel policy, allowing you to effectively manage the organization and reduce the price of the product for the final acquirer;

A network of distribution centers throughout the European part of the Russian Federation, receiving product from large suppliers and preparing it for shipment to stores;

Company, having large park cars and carrying out intercity transportation of goods throughout the European part of the Russian Federation;

About 640 private label products.

Controls

Board of Directors:

1. Pombukhchan Khachatur Eduardovich - Chairman of the Board of Directors

2. Harutyunyan Andrey Nikolaevich

3. Butenko Valery Vladimirovich

4. Galitsky Sergey Nikolaevich

5. Zayonts Alexander Leonidovich

6. Makhnev Alexey Petrovich

7. Shkhachemukov Aslan Yurievich

Audit Committee of the Board of Directors:

1. Zayonts Alexander Leonidovich - Chairman

2. Makhnev Alexey Petrovich

3. Shkhachemukov Aslan Yurievich

Personnel and Remuneration Committee of the Board of Directors:

1. Makhnev Alexey Petrovich - Chairman

2. Butenko Valery Vladimirovich

3. Zayonts Alexander Leonidovich

Governing body:

1. Galitsky Sergey Nikolaevich - Chairman

2. Barsukov Alexander Pavlovich

3. Shaguch Lyubov Azmetovna

4. Churikov Nikita Aleksandrovich

CEO

Galitsky Sergey Nikolaevich

The Magnit chain of stores is

Development strategy

Achieving the maximum coverage area of the Magnit store chain:

Strategic direction- opening stores in cities with a population of less than 500 thousand people - where 73% of the urban population of the Russian Federation lives;

The target audience of the “convenience store” is middle-income buyers, which makes it possible for the Magnit chain to penetrate small cities and towns.

Further development of the network focuses on strengthening the position of the Magnit network in the Ural and Central regions:

Price reduction strategy for regional expansion;

Availability of sufficient funds to ensure the opening of at least 250 stores per year.

Maintaining industry leadership in control costs:

Further improvement of the efficiency of the logistics system.

Magnit stores"have become part of the lives of millions of our fellow citizens. More than 5,000 convenience stores throughout the European part of the Russian Federation offer a full range of everyday goods at affordable prices. Use of high-tech equipment and modern technologies in all areas of business helps to achieve a balance between price and quality of goods from Magnit stores. opens Magnit stores not only in cities, but also in small populated areas, providing residents goods widespread consumption and new jobs. The company does not use a franchise, which allows you to maintain single standard quality of goods and service in all stores of the network. The company is stable and constantly developing. The Magnit retail network in 2011 amounted to about 11.4 billion US dollars.

In 2012, the company plans to open about 800 stores in different regions Russian Federation.

In 2006, as a result of an analysis of customer needs, a decision was made to open stores of a new “family hypermarket” format. Hypermarkets "Magnit" offer customers a wide range of consumer and industrial products for the whole family. Magnit hypermarkets are medium format; they save not only time, but also customers’ time, allowing you to buy everything you need in an average of 40 minutes. In response to customer needs, the organization is constantly improving range goods and services. To ensure the quality of semi-finished products and ready-made dishes in demand on the market, Magnit hypermarkets are opening their own full-cycle production - a meat shop, a culinary department, a bakery and a confectionery shop.

The first Magnit hypermarket was opened in Krasnodar in October 2007; in 2008 there were already 14 of them!

Today the organization has 101 hypermarkets, including in small towns where no large retail chain is present.

In 2012, the company plans to open more than 50 hypermarkets in different regions of the Russian Federation, which means that hundreds will appear in these cities work places for specialists of various professions.

Distribution centers are the largest enterprises companies. Around the clock, the organization’s 17 distribution centers receive product from large suppliers Russian Federation and from different countries world and prepare it for sending to stores and hypermarkets. To maintain the high attractiveness of the company's stores, the Magnit retail chain has been developing own goods of appropriate quality and at the most reasonable prices.

Modern technologies and equipment, automated systems accounting and proprietary IT developments allow the organization’s distribution centers to uninterruptedly supply goods to more than 5,000 stores and 101 hypermarkets of the Magnit retail chain throughout the European part of the Russian Federation.

Motor transport OJSC "Magnit" is one of the largest in Europe, it includes 17 motor transport enterprises in different regions of the Russian Federation. More than 9,200 employees of the transport division provide daily delivery goods to Magnit stores and hypermarkets.

The company's fleet includes more than 3,000 new heavy-duty trucks cars MAN brand (Magnit retail chain is MAN’s largest customer in the world). Our trucking companies are full cycle service cars: modern repair shops, gas stations, car washes, high-tech logistics centers, catering establishments.

Auto transport company- a large transport enterprise in the country, carries out intercity transportation of goods throughout the European part of the Russian Federation, the Urals, the Volga region, as well as international transportation of goods from such countries Europe like Poland, Serbia, Belgium, Spain.

In 2010, the management of the Magnit retail chain made a decision to develop the non-food segment of goods and developed a new store format - "Magnet cosmetics". The first store of the new format was opened at the end of 2010. Analysis work store showed that the organization’s new line of business is in demand in the market. About 300 Magnit-Cosmetic stores have already been opened. In 2012, it is planned to open more than 500 stores of the new format.

The parent organization of the Magnit retail chain is the command center for all business areas of the Magnit retail chain, located in Krasnodar. Strategy is developed here work for several years ahead, ambitious plans are set and achieved throughout the Russian Federation.

Today, the parent company employs more than 4,000 employees - specialists in the field of procurement, transport, logistics, economics and other specialties, which allow them to effectively manage a team of 150,000 employees. Net retail revenue for 2011 amounted to about 11.4 billion. American dollars.

15.04.2017 18:46 1878

What is a magnet and why is it needed?

At your home, on the refrigerator door, you probably have beautiful pictures called magnets. Why are they called that? That's right, because they are held on the refrigerator by a magnet that is attached to the back side.

But the magnet is used not only to attach pictures to the refrigerator. Interested to know what else? We'll tell you about it. But first, let's talk about what a magnet actually is.

Its most famous property is the ability to attract metal objects to itself - paper clips, nails, needles, and basically anything, the main thing is that it is made of metal. This happens with the help of a force called magnetism.

Each magnet has two ends called north and south poles. The north pole of one magnet attracts South Pole the other and then both of them are magnetized. By the way, our planet Earth is also a giant magnet, which has two poles, which are located at the top and bottom of the planet.

There are three main types of magnets - permanent; temporary; and electromagnets. You probably want to ask where they come from?

Permanent magnets are made from natural materials such as iron, ceramics, cobalt, etc.

Temporary magnets are those that have their magnetic (attracting) properties only in the vicinity of permanent magnets. Thus, any metal objects can be considered temporary magnets - scissors, paper clips, pins, etc.

An electromagnet is a coil on which a metal wire is tightly wound. Such a magnet works only if there is a wire passing along the wire wound on the coil. electricity and gives it magnetic, attractive properties.

The attractive force of an electromagnet depends on changes in the magnitude and direction of the electric current passing through the wire. That is, the more powerful the current, the stronger magnet attracts. However, an electromagnet can only work if electricity is connected. Once the electricity is turned off, it loses its power.

Magnets are a very useful thing. For example, they are needed to ensure that the doors of our refrigerators close tightly. Or to collect needles scattered on the floor without getting pierced.

And huge magnets are used in various factories. They are fixed to a crane and thanks to this, heavy metal parts are moved.

The compass needle is also a tiny magnet, so it always points in the direction North Pole. With the help of a compass, people find their way to any part of the Earth. They are used not only on the ground, but also on airplanes and ships.

To understand how they work magnetic poles, you can conduct a simple experiment: take two magnets in your hands and try to press them one against the other.

Different poles (north and south) attract each other. And the same ones (north and north or south and south) repel each other. You will feel this when you begin to bring the magnets closer to each other.

Also, at home you can conduct another interesting experiment called “Floating Compass”. To do this, take (or rather ask your mother) an ordinary sewing needle and magnetize it.

How to do it? To give a needle the properties of a magnet, you need to run a magnet over it approximately 50 times in the same direction. After this, stick a needle into a piece of cork. Place the cork in a bowl of water.

That's all. When the needle calms down, you will see that it is always directed only in one direction - to the north.

Where magnetite deposits were discovered in ancient times.

The simplest and smallest magnet can be considered an electron. Magnetic properties All other magnets are due to the magnetic moments of the electrons inside them. From the point of view of quantum field theory, electromagnetic interaction is carried by a massless boson - a photon (a particle that can be represented as a quantum excitation of the electromagnetic field).

Weber - magnetic flux, when it decreases to zero, an amount of electricity of 1 coulomb passes through the circuit connected to it with a resistance of 1 ohm.

Henry - international unit inductance and mutual induction. If a conductor has an inductance of 1 H and the current in it varies uniformly by 1 A per second, then an emf of 1 volt is induced at its ends. 1 henry = 1.00052 10 9 absolute electromagnetic units of inductance.

Tesla- unit of measurement of magnetic field induction in SI, numerically equal to induction such a uniform magnetic field in which per 1 meter of length of a straight conductor, perpendicular to the vector magnetic induction, with a current of 1 ampere a force of 1 newton acts.

Use of magnets

Magnetic storage media: VHS cassettes contain reels of magnetic tape. Video and audio information is encoded onto a magnetic coating on the tape. Also, in computer floppy disks and hard drives, data is recorded on a thin magnetic coating. However, storage media are not magnets in the strict sense, since they do not attract objects. Magnets in hard drives are used in drive and positioning motors.
Credit, debit, and ATM cards all have a magnetic stripe on one side. This band encodes the information needed to connect to financial institution and connections to their accounts.
Conventional TVs and Computer Monitors: TVs and computer monitors containing a cathode ray tube use an electromagnet to control a beam of electrons and form an image on the screen. Plasma panels and LCD displays use different technologies.
Loudspeakers and microphones: Most loudspeakers use a permanent magnet and a current coil for conversion electrical energy(signal) into mechanical energy (the movement that creates sound). The winding is wound on a coil, attached to the diffuser and flows through it alternating current, which interacts with the field of a permanent magnet.
Another example of the use of magnets in audio engineering is in the pickup head of an electrophone and in cassette recorders as an economical erasing head.

Magnetic heavy mineral separator

Electric motors and generators: Some electric motors (as well as loudspeakers) rely on a combination of an electromagnet and a permanent magnet. They convert electrical energy into mechanical energy. A generator, on the other hand, converts mechanical energy into electrical energy by moving a conductor through a magnetic field.
Transformers: Devices that transfer electrical energy between two windings of wire that are electrically insulated but coupled magnetically.
Magnets are used in polarized relays. Such devices remember their state when the power is turned off.
Compasses: A compass (or marine compass) is a magnetized pointer that can rotate freely and aligns itself with the direction of a magnetic field, most commonly the Earth's magnetic field.
Art: Vinyl magnetic sheets can be attached to paintings, photographs and other decorative items, allowing them to be attached to refrigerators and other metal surfaces.

Magnets are often used in toys. M-TIC uses magnetic bars connected to metal spheres

Egg-shaped rare earth magnets that attract each other

Toys: Given their ability to withstand gravity at close range, magnets are often used in children's toys with fun effects.
Magnets can be used to make jewelry. Necklaces and bracelets can have a magnetic clasp, or can be made entirely from a series of linked magnets and black beads.
Magnets can pick up magnetic objects (iron nails, staples, tacks, paper clips) that are either too small, difficult to reach, or too thin to handle with your fingers. Some screwdrivers are specially magnetized for this purpose.
Magnets can be used in scrap metal processing to separate magnetic metals (iron, steel and nickel) from non-magnetic ones (aluminum, non-ferrous alloys, etc.). The same idea can be used in what is called a "Magnetic Test", in which the car body is examined with a magnet to identify areas repaired using fiberglass or plastic putty.
Maglev: train on magnetic suspension, driven and controlled by magnetic forces. Such a train, unlike traditional trains, does not touch the rail surface during movement. Since there is a gap between the train and the moving surface, friction is eliminated, and the only braking force is the force of aerodynamic drag.
Magnets are used in furniture door latches.
If magnets are placed in sponges, then these sponges can be used to wash thin sheets of non-magnetic materials on both sides at once, with one side being difficult to reach. This could be, for example, the glass of an aquarium or balcony.
Magnets are used to transmit torque “through” a wall, which could be, for example, a sealed container of an electric motor. This is how the GDR toy was designed. Submarine" In the same way, in household water flow meters, rotation is transmitted from the sensor blades to the counting unit.
Magnets together with a reed switch are used in special position sensors. For example, in refrigerator door sensors and security alarms.
Magnets together with a Hall sensor are used to determine the angular position or angular velocity shaft
Magnets are used in spark gaps to speed up arc extinction.
Magnets are used for non-destructive testing using the magnetic particle method (MPC)
Magnets are used to deflect beams of radioactive and ionizing radiation, for example when observing in cameras.
Magnets are used in indicating instruments with a deflecting needle, such as an ammeter. Such devices are very sensitive and linear.
Magnets are used in microwave valves and circulators.
Magnets are used as part of a deflection system of cathode ray tubes to adjust the trajectory of the electron beam.
Before the discovery of the law of conservation of energy, there were many attempts to use magnets to build a “perpetual motion machine”. People were attracted by the seemingly inexhaustible energy of the magnetic field of permanent magnets, which have been known for a very long time. But the working model was never built.
Magnets are used in non-contact brake designs consisting of two plates, one is a magnet and the other is made of aluminum. One of them is rigidly fixed to the frame, the other rotates with the shaft. Braking is controlled by the gap between them.

Magnetic toys

Uberorbs
Magnetic constructor
Magnetic drawing board
Magnetic letters and numbers
Magnetic checkers and chess

Medicine and safety issues

Due to the fact that human tissues are very low level susceptibility to static magnetic field does not exist scientific evidence its effectiveness for use in the treatment of any disease. For the same reason, there is no scientific evidence of a risk to human health associated with exposure to this field. However, if a ferromagnetic foreign body is in human tissue, the magnetic field will interact with it, which can pose a serious danger.

Magnetization

Demagnetization

Sometimes the magnetization of materials becomes undesirable and it becomes necessary to demagnetize them. Demagnetization of materials is achieved in various ways:

heating a magnet above the Curie temperature always leads to demagnetization;
place a magnet in an alternating magnetic field that exceeds the coercive force of the material, and then gradually reduce the effect of the magnetic field or remove the magnet from it.

The latter method is used in industry for demagnetizing tools, hard drives, erasing information on magnetic cards, and so on.

Partial demagnetization of materials occurs as a result of impacts, since a sharp mechanical impact leads to domain disorder.

Notes

Literature

Savelyev I. V. Well general physics. - M.: Nauka, 1998. - T. 3. - 336 p. - ISBN 9785020150003