cell membrane also called plasma (or cytoplasmic) membrane and plasmalemma. This structure not only separates the internal contents of the cell from the external environment, but also enters into the composition of most cell organelles and the nucleus, in turn separating them from the hyaloplasm (cytosol) - the viscous-liquid part of the cytoplasm. Let's agree to call cytoplasmic membrane one that separates the contents of the cell from the external environment. The remaining terms refer to all membranes.

The structure of the cell membrane

The basis of the structure of the cell (biological) membrane is a double layer of lipids (fats). The formation of such a layer is associated with the features of their molecules. Lipids do not dissolve in water, but condense in it in their own way. One part of a single lipid molecule is a polar head (it is attracted by water, i.e., hydrophilic), and the other is a pair of long non-polar tails (this part of the molecule is repelled by water, i.e., hydrophobic). This structure of the molecules makes them "hide" their tails from the water and turn their polar heads towards the water.

As a result, a lipid bilayer is formed, in which the non-polar tails are inside (facing each other), and the polar heads are facing out (to the external environment and cytoplasm). The surface of such a membrane is hydrophilic, but inside it is hydrophobic.

In cell membranes, phospholipids predominate among lipids (they are complex lipids). Their heads contain a residue of phosphoric acid. In addition to phospholipids, there are glycolipids (lipids + carbohydrates) and cholesterol (belongs to sterols). The latter gives the membrane rigidity, being located in its thickness between the tails of the remaining lipids (cholesterol is completely hydrophobic).

Due to electrostatic interaction, certain protein molecules are attached to the charged heads of lipids, which become surface membrane proteins. Other proteins interact with non-polar tails, partially sink into the bilayer, or penetrate it through and through.

Thus, the cell membrane consists of a bilayer of lipids, surface (peripheral), immersed (semi-integral), and penetrating (integral) proteins. In addition, some proteins and lipids on the outside of the membrane are associated with carbohydrate chains.

it fluid mosaic model of the membrane structure was put forward in the 70s of the XX century. Prior to this, a sandwich model of the structure was assumed, according to which the lipid bilayer is located inside, and on the inside and outside the membrane is covered with continuous layers of surface proteins. However, the accumulation of experimental data disproved this hypothesis.

The thickness of membranes in different cells is about 8 nm. Membranes (even different sides of one) differ from each other in the percentage of different types of lipids, proteins, enzymatic activity, etc. Some membranes are more liquid and more permeable, others are more dense.

Breaks in the cell membrane easily merge due to the physicochemical characteristics of the lipid bilayer. In the plane of the membrane, lipids and proteins (unless they are fixed by the cytoskeleton) move.

Functions of the cell membrane

Most of the proteins immersed in the cell membrane perform an enzymatic function (they are enzymes). Often (especially in the membranes of cell organelles) enzymes are arranged in a certain sequence so that the reaction products catalyzed by one enzyme pass to the second, then the third, etc. A conveyor is formed that stabilizes surface proteins, because they do not allow enzymes to swim along the lipid bilayer.

The cell membrane performs a delimiting (barrier) from environment and at the same time the transport function. It can be said that this is its most important purpose. The cytoplasmic membrane, having strength and selective permeability, maintains the constancy of the internal composition of the cell (its homeostasis and integrity).

In this case, the transport of substances occurs different ways. Transport along a concentration gradient involves the movement of substances from an area with a higher concentration to an area with a lower one (diffusion). So, for example, gases diffuse (CO 2, O 2).

There is also transport against the concentration gradient, but with the expenditure of energy.

Transport is passive and lightweight (when some carrier helps him). Passive diffusion across the cell membrane is possible for fat-soluble substances.

There are special proteins that make membranes permeable to sugars and other water-soluble substances. These carriers bind to transported molecules and drag them across the membrane. This is how glucose is transported into the red blood cells.

Spanning proteins, when combined, can form a pore for the movement of certain substances through the membrane. Such carriers do not move, but form a channel in the membrane and work similarly to enzymes, binding a specific substance. The transfer is carried out due to a change in the conformation of the protein, due to which channels are formed in the membrane. An example is the sodium-potassium pump.

The transport function of the eukaryotic cell membrane is also realized through endocytosis (and exocytosis). Through these mechanisms, large molecules of biopolymers, even whole cells, enter the cell (and out of it). Endo- and exocytosis are not characteristic of all eukaryotic cells (prokaryotes do not have it at all). So endocytosis is observed in protozoa and lower invertebrates; in mammals, leukocytes and macrophages absorb harmful substances and bacteria, i.e. endocytosis performs protective function for the body.

Endocytosis is divided into phagocytosis(cytoplasm envelops large particles) and pinocytosis(capture of liquid droplets with substances dissolved in it). The mechanism of these processes is approximately the same. Absorbed substances on the cell surface are surrounded by a membrane. A vesicle (phagocytic or pinocytic) is formed, which then moves into the cell.

Exocytosis is the removal of substances from the cell by the cytoplasmic membrane (hormones, polysaccharides, proteins, fats, etc.). These substances are enclosed in membrane vesicles that fit the cell membrane. Both membranes merge and the contents are outside the cell.

The cytoplasmic membrane performs a receptor function. To do this, on its outer side there are structures that can recognize a chemical or physical stimulus. Some of the proteins penetrating the plasmalemma are connected from the outside to polysaccharide chains (forming glycoproteins). These are peculiar molecular receptors that capture hormones. When a particular hormone binds to its receptor, it changes its structure. This, in turn, triggers the cellular response mechanism. At the same time, channels can open, and certain substances can begin to enter the cell or be removed from it.

The receptor function of cell membranes has been well studied based on the action of the hormone insulin. When insulin binds to its glycoprotein receptor, the catalytic intracellular part of this protein (the enzyme adenylate cyclase) is activated. The enzyme synthesizes cyclic AMP from ATP. Already it activates or inhibits various enzymes of cellular metabolism.

The receptor function of the cytoplasmic membrane also includes the recognition of neighboring cells of the same type. Such cells are attached to each other by various intercellular contacts.

In tissues, with the help of intercellular contacts, cells can exchange information with each other using specially synthesized low molecular weight substances. One example of such an interaction is contact inhibition, when cells stop growing after receiving information that the free space is occupied.

Intercellular contacts are simple (membranes of different cells are adjacent to each other), locking (invagination of the membrane of one cell into another), desmosomes (when the membranes are connected by bundles of transverse fibers penetrating into the cytoplasm). In addition, there is a variant of intercellular contacts due to mediators (intermediaries) - synapses. In them, the signal is transmitted not only chemically, but also electrically. Synapses transmit signals between nerve cells, as well as from nerve to muscle.

In 1823, the Scottish chemist Charles Mackintosh, conducting another experiment, smeared the sleeve of his jacket with a rubber solution and after some time noticed that the sleeve of the jacket did not get wet. He patented this invention and founded Charles Macintosh and Co. for the production of waterproof products - macs.

But if the fashion of 200 years ago can still find a second wind in our days, then this definitely cannot be said about the weather protection technologies of those times.

Today they have been replaced by membranes - the result of two hundred years of evolution in the struggle of people for comfort in any weather.

In more detail, the question of what is a membrane will be answered by a sales specialist of a sports store MySport- Karina Radionova.

How should you dress in autumn so as not to get wet?

For autumn-spring and winter periods When high humidity, moderate or high precipitation are characteristic, the main criterion for choosing clothing is its water-repellent properties. To protect against moisture, there is a membrane or a special coating (impregnation).

- What is the difference between a membrane and such a water-repellent coating?

The second option for weather protection (water-repellent impregnation) is not permanent. This option is suitable for a short stay outside during light rain, but this product is not intended for walking in the rain. The membrane allows us to be in the rain for a longer time. In this case, the product will breathe, that is, remove fumes from our body from the inside.

- How to understand the wording: to remove fumes from our body?

Draw sweat away from the body. The fact is that we associate rain protection with a raincoat, but a raincoat is the effect of a steam room, it does not breathe, we will not be able to feel comfortable in it while walking, for example. A product with a membrane will breathe.

What is a membrane anyway?

A membrane is a very thin layer of film applied to the top material of a product. It can be glued to the fabric, hot applied, welded. Also, the membrane can be located between the lining and top material. It is used in clothes, shoes and accessories.

The most common is the pore membrane. It consists of huge amount micro-holes that allow our fumes to escape from the body to the outside, but at the same time does not allow precipitation to pass into the jacket.

There are also non-porous and combined membranes. They work differently. In the case of non-porous due to the lack of holes, it will work on the principle of diffusion. The membrane will need to accumulate our moisture on the inner walls to a certain amount in order to take it out through diffusion. The advantage of this membrane is that it is durable. It does not consist of pores that can become clogged and clogged. The disadvantage is that you need to wait until this membrane starts working, until it accumulates evaporation. This can cause a certain feeling of discomfort, it may even seem to us that we are wet. This principle of operation of this membrane, in contrast to the microporous one, which starts working immediately, and we feel dryness and comfort.

The third type is the combined membrane. She combines best performance the two previous ones. It works like this: a porous membrane is adjacent to the body, which quickly removes moisture, the next layer - non-porous - protects us from unpleasant environmental influences and increases the wear resistance of the inner layer. The advantage of such a membrane is that it is more durable and starts working immediately.

- Will it be the most expensive?

Yes, it is the most expensive and exclusive. It is rare in stores with outdoor equipment. As a rule, products with it are made to order for more professional, extreme use.

- What about the city? Which membrane will be the most suitable?

For everyday use the best option there will be a pore membrane. It, like every membrane, has such important characteristics as water resistance and vapor conductivity.

- It turns out that according to the criterion of water resistance, we choose a membrane?

Yes, according to this criterion. Water resistance is protection from rain in the autumn-spring period, and in winter - from snow. The waterproofing index of a membrane is measured in millimeters of water column per square meter of a product with a membrane. There are basic, intermediate and professional levels of membrane use. We refer to the first membrane with an indicator of 3-5 thousand, to the average - from 5 to 10 thousand, and already over 10 we are talking about a professional level, about extreme conditions of use.

The indicator indicated in numbers indicates how much water pressure the membrane can withstand and not get wet. There is an opinion that you should not pay attention to membranes with an indicator of less than 10 thousand. It is erroneous. Membranes with a lower indicator will also be effective, it all depends on the conditions of use. For the city, with light precipitation, an indicator of 3-5 thousand will be enough. Most often, in urban environments, we do not need long or constant walks in the rain.

Vapor permeability or moisture removal is also an important property of the membrane. It is important for people who prefer outdoor activities, when the rapid removal of moisture from the body to the surface of the product matters. Steam conductivity is measured in grams per square meter, and the time interval is 24 hours, that is, how much steam the membrane can remove per day with active use, when moving. As a rule, both indicators are equated to each other, that is, if the brand indicates, for example, 5 thousand, then this applies to both water resistance and vapor conductivity. However, it happens that the numbers are written separately.

If after reading this article you have a burning desire to buy such a wonderful jacket for yourself or your loved ones and spend autumn in dryness, warmth and comfort - you are in stores MySport!

And so that you can make purchases profitably, there is a promotion in stores now - When buying three items, the second item is 20% off, and the third item is 40% off.

The entire range of products participates in the promotion, and membrane jackets can be purchased not only for adults, but also for children!

The most interesting news of the Magic Card in our channels:

The development of innovative technologies has also affected fabrics, so the question of what a membrane is in clothing and what it is intended for is becoming increasingly relevant. It is one of the multifunctional canvases of the modern range. This material is semi-permeable, presented in the form of a film with a special structure.

Membrane clothing and shoes are able to repel moisture from the outside and evaporate it from the inside. From below, such a material is quite soft, from above it is harder, as it is protective and resistant to wear. The middle layer is the membrane and the protective material.

Caring parents often ask questions about the membrane in clothes for children: what is it, is it dangerous and is it worth buying it? The answers to all these questions can be found in our article. This material is actively used to create various elements of both children's and adult clothing, so this information will certainly be useful to everyone.

Properties

Knowing that the membrane in clothing is a synthetic material, many people want to know its properties. They will help determine its purpose and need for modern society. The membrane structure is characterized by:

1. Waterproof. This parameter is represented in digital form. It denotes the water pressure that matter can withstand. When choosing a particular product, be sure to pay attention to this. Clothes and shoes marked 3000 can withstand only light rain, material 10000 is able to overcome heavy rain, but the indicator 20000 guarantees the waterproofness of the product even in stormy conditions.
2. Wind protection. Regardless of the waterproof rating, any item of clothing will protect its wearer from the wind. Membrane products will never let people shudder.
3. Vapor release. The third criterion is also of particular importance and is also presented in number format. It indicates the amount of steam in a certain area (g / m 2), which comes out during the day. The quality of the material depends on this criterion - the higher it is, the better the material.

Reviews about membrane clothing are always positive. This is largely due to its above-described capabilities. It is thanks to them that clothes and shoes made from such fabrics are popular in different countries among people of all ages.

Varieties

Both for adults and children, winter membrane clothing is presented in various variations. Today there are the following types of matter:

1. Double layer. They are produced using a unique technology, the essence of which is that the membrane is glued to the inside of ordinary matter, and on top of it there is a reliable protective lining.
2. Three-layer. These options are the basis of the membrane itself and the knitted mesh. The layers are bonded together by lamination. The lining in this case acts as a grid. This technology makes it possible to reduce the weight of the finished product.
3. Double layer with knitted lining. The design of this material is quite similar to the previous one. The only difference is that the regular lining has been replaced with foam jersey. Clothing of this type has even less weight, but this does not change its properties in any way.

Compound

It is better to understand what a membrane is in clothes, its composition will help. Modern fabrics are made from such materials:

1. Polyester. This element can keep its shape perfectly. It is quite pleasant to the body. Its consumers love for its long service life and high performance strength.
2. Tencel. Everyone knows this material due to its softness and ability to absorb moisture. It is obtained from the eucalyptus tree.
3. Cotton. In membrane clothing, it is an important element. This material is soft to the touch, it absorbs all the moisture and retains heat.
4. Bamboo. Such a canvas is distinguished by its high strength, as well as hypoallergenicity. Bamboo can hold Sun rays and eliminate bad odors.
5. Teflon. This matter has micropores on the outside. She doesn't let the water through. The only drawback of Teflon is the possibility of clogging pores, which disrupts the process of moisture evaporation.
6. Polyurethane. In this case, there are no pores on the surface, but the matter still does not let moisture through. All liquid penetrating inside accumulates from the inside, and then evaporates. Among the disadvantages is the fact that it will take a long time to eliminate water.
7. Combined matter. In the inner part, a foam rubber membrane is provided, on top of which there is a protective layer that prevents the pores from clogging. The combined material has all the advantages of Teflon and polyurethane.

It is due to these components that all adult and children's upper membrane clothing can be safely used in inclement weather. The material will keep you warm and dry in all conditions.

Usage

Outer membrane clothing is now made for both adults and children. As a rule, these are overalls, for the creation of which high-quality nylon or dense polyester is used. In addition, this matter has shown itself well in sewing moisture-resistant suits.

Athletes who go to competitions outside their country in the winter or autumn period of the year know that the membrane in clothing is the best option for them. To date, the production of costumes for such people is carried out by:

• Transactive;
• Porelle;
• Ultimex;
• Cyclone.

At the same time, the fabric is in the greatest demand in the following areas:

• mountaineering;
• mountain and ski tourism;
• travels;
• fishing;
• leisure;
• hunting;
• any winter sports.

Price

After learning what a membrane is in clothes, many people want to buy it. The average cost of matter is 400 rubles per meter. But this amount is determined not only by the type of material, but also by its manufacturer, so some goods can cost buyers 3-4 times more.

On this occasion, there are only positive reviews about the membrane (clothes) for children and adults. For some, such a price may indeed seem high, but in fact, the quality and capabilities of the product justify it. Therefore, buyers have no complaints about the clothes and the fabric itself.

Advantages and disadvantages

Membrane sportswear has certain features that you need to know about before buying it. Like any material, the membrane has its advantages and disadvantages, for which it can please buyers or, conversely, repel them.

Among the positive qualities, the following points can be distinguished:

• lightness and comfort (both children's and adult costumes allow a person to move freely without constraining him or limiting him in this);
• no need for an additional layer of warm clothes (this nuance is especially important for small children, since with several sweaters they always feel discomfort);
• ease of washing and cleaning (membrane fabric is quickly cleaned of any contaminants and does not require the purchase of any special expensive products).

The disadvantages include:

• fragility (this nuance depends on the category of fabric);
• the need for right choice the bottom layer (this will take a lot of time, if initially there were no ideas about clothes).

Membrane fabric is not intended for heating, but it perfectly reduces the sweating of its owner and does not allow the body to cool. Sedentary children are best to buy winter suits with a special insulating lining. At the same time, it is worth paying attention to the fact that membrane clothing is not entirely suitable for daily wear, since its purpose is only some of the situations already described above (mountaineering, mountain holidays, tourism, and so on).

What to wear under these clothes

Having figured out what a membrane is in clothes, you should decide on the wardrobe items that need to be worn under it. In the winter season, be sure to follow the correct principle of selecting layers. It will help protect the body from overheating and a sharp reaction to temperature changes. At the same time, it must be remembered that the membrane material breathes well, due to which sweating is completely eliminated.

Most often, people dress in three layers:

• internal (underwear);
• medium (ordinary attire - jacket, trousers);
• upper (the winter membrane suit itself, protecting from the wind).

Wash

Children's winter clothes from the membrane requires proper care to maintain its strength. It is not recommended to wash it with a detergent, as it will simply clog the pores and they will not skip Fresh air. The list of these products includes various conditioners, conditioners, powders, and so on.

You can wash clothes with laundry or liquid soap. During the washing period, the matter remains safe and sound, but impurities can remain in the pores. The properties of the membrane will not change if it is cleaned in this way. But even so, outerwear it is better to wear carefully, avoiding strong stains.

Clean things from dirt washing machine is strictly prohibited. It does not have a very good effect on the coating, because its work provides for soaking and the subsequent spin mode. Hand washing is the best way to deal with soiling of membrane clothing. The ideal water temperature for this would be 30-40 degrees.

Before starting the procedure, you need to connect the sleeves of the jacket and fasten all the rivets and fasteners located on it. After washing, the thing should not be wrung out, since to speed up its drying it will be enough just to blot the fabric with an absorbent cloth. It should be remembered that the drying process must be carried out on a horizontal surface.

special care

Membrane children's clothing for the winter is by no means ironed after washing. This does not depend on the season, since a thing at any time at elevated temperatures can deteriorate externally. You can restore the water-repellent properties of the membrane using a special spray based on fluorine. Thanks to this agent, a reliable film is formed on the surface of clothing, which will protect and reduce negative impact ultraviolet rays.

Storage

On days when membrane clothing is not in use, it must be stored on a hanger. It must always be in an upright position. To provide it with protection from clogging of the porous structure, it is required to put a polyethylene cover on top. You also need to remember that such clothes should not be stored crumpled and wet. Therefore, before sending things to the closet, they need to be thoroughly washed in accordance with the rules described above and dried.

Manufacturers

Today, Gore-TeX is very popular. She is engaged in the production of membrane clothing. Initially, the brand produced equipment designed for astronauts, but a little later it offered high-quality kits for mountain tourists, skiers and mountaineers.

By the criterion of quality, you can compare the products of Triple-Point, ULTREX, Sympatex. These products are distinguished by solid material, which is supplied in various modifications. Their cost, of course, is high, but it is consistent with the capabilities of the products.

Ceplex, Fine-Tex membrane items are available for many consumers. They are designed for only two seasons, but only if they are actively used. After this period, the material gradually begins to let moisture through, which will no longer be possible to fix.

When choosing one or another membrane product, you must definitely pay attention to the information about gluing the seams. It is indicated on each item of clothing. In most products, absolutely all seams are glued, but there may also be those where only the main ones are properly processed. For people who are engaged in active sports, it is best to choose clothes where all seams will be securely reinforced.

Shoes

Special membrane shoes are intended only for professional athletes and people who prefer outdoor activities outside the city. But despite this, in modern times it is used in everyday life. Warm, fairly light in weight and moisture resistant shoes are an excellent option not only for the rainy off-season, but also for the harsh winter. Decent air circulation contributes to maintaining a comfortable microclimate inside, as well as maintaining the optimal temperature of the feet for a long time.

A distinctive feature of membrane footwear, as well as clothing, is the presence in it of a high-tech polymer material with small pores. It is quite tightly fixed between the upper padding and the inner lining. The minimum size of the holes in this intermediate layer does not let moisture in and does an excellent job of removing natural fumes. From this we can conclude that membrane shoes are good air circulation and maintaining optimal dryness and warmth of the feet in all weather conditions.

How to keep shoes in good condition

Any footwear, including membrane, is required proper care. He will help keep her beautiful appearance and thermoregulating properties, as well as to extend the service life. This wardrobe item needs to be dried only at room temperature, but in no case should heating appliances be used, as they will quickly violate the integrity of the structure. In this case, it is best to remove the insole first.

As soon as necessary, shoes should be cleaned of dust and dirt. If the surface is made of leather, then it is better to wipe it soft cloth, a special brush is more suitable for nubuck, but you can take a sponge to clean textiles. Too heavily soiled shoes can be washed with a soapy solution or some kind of water-based product, but without fats and oils in the composition.

Regularly apply compounds to shoes that will repel moisture. They will protect the material and increase the service life, while maintaining the original appearance.

(from lat. membrana - skin, membrane) in acoustics, a flexible thin film, given external. forces into a state of tension and, as a result, elasticity. It is necessary to distinguish a plate from M., a cut depends on its material and thickness. Examples of M. - skin stretched on a drum, thin metallic. foil, which plays the role of a movable lining of a condenser microphone. Own M. are represented by systems of standing waves with one or another picture of nodal lines, to-rye separate parts of M., oscillating with opposite phases (Fig.); ext. the contour, along which the M. is clamped, is always a nodal line, if the fixation is such that there is no displacement perpendicular to the M. plane. systems of standing waves correspond to dec. oscillation frequencies, the totality of which determines the discr. own frequencies M. Forced oscillations M. under the action of concentrated or distributed periodic. ext. forces occur with a frequency of ext. impact; when it coincides with one of the properties. frequencies M. takes place.

The form of some properties. vibrations of the membrane: a - rectangular; b - round. The arrows indicate the nodal lines; i, k - numbers of harmonics.

Physical Encyclopedic Dictionary. - M.: Soviet Encyclopedia. Editor-in-Chief A. M. Prokhorov. 1983 .

(from lat. membrana - skin, membrane) - a flexible thin film, given externally. forces into a state of tension and, as a result, elasticity. M. refers to two-dimensional fluctuations. systems with distributed parameters. The elasticity of M. depends only on its material and tension, in contrast to plate, the elasticity of a cut is determined by its material and thickness. Distinguish, a feature of M. is the need to secure it on the outside. contour. Examples of M. are skin stretched over a drum, thin metallic. foil, which plays the role of a movable lining of a condenser microphone, etc.

Neglecting the dissipation of energy, oscillations of a homogeneous, uniformly stretched M. can be described by the equation

where - the displacement of the surface element M. from the equilibrium position in the direction of the normal to the plane of tension, - surface M., T- tension, - Laplace operator. Boundary conditions for M.on ext. contour; as the beginning conditions is given by the displacements and velocities of the points of the surface M. in the beginning. moment of time t= 0. Natural (free) oscillations of M. are represented by systems of standing waves. M.'s sections, oscillating with opposite phases, are separated by nodal lines. The totality of own vibration frequencies M. is a discrete spectrum. For a rectangle M. (Fig. 1) with sides a and 6 own. frequencies are expressed f-loy

The frequency w is fundamental (lowest); overtones, etc. are the harmonics of the main. frequencies. Case (square M.) called. degenerate, in square M. a simple harmonic is possible. in the form of traveling waves, while the nodal lines during the period consistently take dec. configuration.

Rice. 1. The shape of the first four natural oscillations of a rectangular membrane; arrows indicate nodal lines.

Rice. 2. The shape of a round membrane for some natural oscillations; arrows indicate nodal lines.

Own oscillation frequency of round M. (Fig. 2) radius a can be found from the equation

where J k - Bessel function of the 1st kind k th order, a k and l are the numbers of nodal diameters and nodal circles, respectively. In the case of a round M., none of the overtones is a harmonic of the main. frequency w 01 .

Forced vibrations M. occur with a frequency of ext. impact, when coinciding with a swarm with one of their own. frequency takes place resonance. M. is a sound emitter with an uneven distribution of vibrations. surface speed. Radiation M., excited on the main. frequency, has less directivity than at the same frequency of a piston diaphragm of the same configuration.

Lit.: Strett D JK. V. (Lord Rayleigh), Theory of sound, trans. from English, 2nd ed., vol. 1, M., 1955; Morse F., Fluctuations and, trans. from English, M.-L., 1949; Skuchik E., Fundamentals of acoustics, trans. from German, vol. 1, M., 1958. S. V. Egerev.

Physical encyclopedia. In 5 volumes. - M.: Soviet Encyclopedia. Editor-in-Chief A. M. Prokhorov. 1988 .

See what "MEMBRANE" is in other dictionaries:

Membrane- a thin flexible plate, fixed around the perimeter, designed to separate two cavities with different pressures or separate a closed cavity from the total volume, as well as to convert pressure changes into linear movements and ... ... Dictionary-reference book of terms of normative and technical documentation

- (Membrane, diaphragm) thin, flexible, stretched plate. Round membranes, clamped around the circumference, are used in all sound transmitting and sound receiving devices (telephone, microphone, gramophone). Such a membrane easily responds to vibrations ... ... Marine Dictionary

Diaphragm, pendulum, resonator, damper; membrane, diffuser, pneumomembrane Dictionary of Russian synonyms. membrane noun, number of synonyms: 9 axolemma (1) … Synonym dictionary

membrane- Ndp. diaphragm A flexible, contoured partition separating two cavities with different pressures or separating a cavity from space and converting pressure changes into movement or vice versa [GOST 21905 76] membrane Thin flexible ... ... Technical Translator's Handbook

Membrane- * membrane * membrane is a thin boundary structure located on the surface of cells and intracellular particles, as well as tubules and vesicles in the cellular contents. Performs various biological functions provides cell permeability ... ... Genetics. encyclopedic Dictionary

- (from Latin membrana membrane) 1) in the theory of elasticity, an infinitely thin film fixed along the contour, the elastic modulus of which in the direction perpendicular to the surface is zero. 2) In technology, a thin film or plate (usually fixed along ... ... Big Encyclopedic Dictionary

MEMBRANE, in biology, the boundary layer inside or around a living CELL or TISSUE. Cell membranes include the plasma membrane surrounding the cell, the system of membranes within the cell (ENDOPLASMATIC NET) and the double membrane around the cell ... ... Scientific and technical encyclopedic dictionary

MEMBRANE, membranes, for women (lat. membrana membrane) (physical, technical). A membrane or thin plate of elastic material fixed along the edges, capable of making the vibrations necessary to capture and reproduce sound waves. Dictionary… … Explanatory Dictionary of Ushakov

MEMBRANE, s, female. An elastic membrane, a thin film or plate capable of vibrating. M. phone. | adj. membrane, oh, oh. Membrane musical instruments. Explanatory dictionary of Ozhegov. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 ... Explanatory dictionary of Ozhegov

MEMBRANE, or membrane, a thin plate of any substance. It is used in acoustics to reproduce sound vibrations. The presence of natural vibrations in acoustic M. distorts the nature of the sound. In colloidal chemistry, M. is used for ... ... Big Medical Encyclopedia

Thanks to the development of innovative technologies for the invention of fabrics, today in the assortment you can see wide selection of multifunctional canvases, the membrane remains one of them. This is a semi-permeable material, which is presented in the form of a film with a special structure. Multilayer canvases that are equipped with such a film are called membrane.

In ready-to-wear, they are able to repel water on the outside, but still allow the moisture that forms inside to evaporate. The bottom layer of the material is soft, while the top layer is protective and resistant to wear. But the middle one is a protective matter and a membrane.

Fabric Description Membrane

The membrane is a synthetic material. It has the following properties:

1. Waterproof. This indicator is presented in digital form. Denotes the pressure of water that matter can withstand. When buying membrane-based products, this criterion must be taken into account. If the product has the number 3.000, this indicates that the material is able to resist light rain. But the material with an indicator of 10.000 is not afraid of a heavy downpour. A material with 20.000 is a product that will not get wet even in severe weather and stormy conditions.
2. Vapor recovery. This criterion is also presented in number format. Displays the amount of steam in g/m2 of the web that comes out per day. The higher this criterion, the better the material.
3. Wind protection. With membrane-based products, you don’t have to worry that you will shudder from a strong wind.

Types and characteristics of the membrane material

Membrane fabric is presented today various types. If we consider the fabric according to the designs of the canvas, then there are such types:

A distinctive feature is that instead of a lining there is a foam jersey. Such clothes made of a membrane have even less weight, but at the same time this is not reflected in any way on its properties.

On the video - a description of the fabric membrane:

Compound

Membrane fabrics today can be obtained based on the following materials:

1. Tensela. This material is obtained on the basis of eucalyptus wood. The fabric is soft, pleasant to the body and perfectly absorbs moisture. You can read in detail at the link.
2. Polyester. This material is known to all for its ability to hold its shape. It is pleasant to the body, does not wrinkle, has high strength and long term services. Are described here.
3. Cotton. It is a soft material that is pleasant to the touch. It does not create static electricity, retains heat and absorbs moisture. Listed at the link.
4. Bamboo. This fabric is hypoallergenic and durable. It traps the sun's rays, absorbs moisture and unpleasant odors, and is also pleasant to the body. you can find out what bamboo fiber is, whether it is synthetic or not.
5. Teflon. This matter is equipped with micropores that are present on the outer surface. The material does not allow water to pass through, but at the same time moisture evaporates perfectly without collecting inside. The disadvantage of the material is that the pores can become clogged, as a result of which the evaporation process is disrupted.
6. Polyurethane. There are no pores on its surface. The material does not pass water. The moisture that is concentrated inside first accumulates on the wrong side, and then evaporates. The disadvantage of the canvas is that the evaporation of moisture does not occur immediately, as a result of which it may seem that the product is wet. Also read.
7. Combined material. Inside the canvas is a foam membrane, and on top of it is a protective layer. It doesn't let pores get clogged. Such a material has all the advantages that are characteristic of polyurethane and Teflon.

In the photo - the membrane tissue device:

Application

Membrane fabric today has become actively used for the manufacture of workwear. In the production of jackets, technology is used using dense polyester or high quality nylon. Also, the membrane fabric has proven itself well when sewing moisture-resistant suits.

Very often, in the manufacture of clothing, membrane fabric is used by the following manufacturers:

In addition to the manufacture of workwear, membrane fabric is in great demand in the following industries:

• ski and mountain tourism;
• mountaineering;
• hunting and fishing;
• winter sports;
• travel and outdoor activities.

Video: fabric application: clothing, insulation, lining

The video tells about the use of membrane fabric as a heater:

Price per meter

The average wholesale price for a membrane sheet is 350 rubles per m., taking into account the manufacturer and the characteristics of the matter, the cost can take a maximum mark of 1,500 rubles per m.