illustrate
Mercury thermometers, gaps in the tip of a pen, gaps between towels and blotting paper fibers, soil structures and tiny gaps in the veins of roots, stems and leaves of plants can all be considered as capillaries. Capillary electrochromatography is a new micro-separation analysis technology, which combines the advantages of capillary electrophoresis and micro-diameter column liquid chromatography. By applying DC high-voltage electric field to both ends of the micro-diameter column filled with particulate liquid chromatography packing, its excellent separation ability for trace complex biological and chemical system samples is realized.
Thin-tube air conditioning: The capillary network simulates the mechanism of veins and human capillaries, and consists of capillaries with an outer diameter of 3.5-5.0mm (with a wall thickness of about 0.9mm) and a main donor return pipe with an outer diameter of 20mm (with a wall thickness of 2mm or 2.3mm). The combination of insulation layer, heat dissipation layer and capillary network forms a capillary network heat exchanger, which greatly improves the heat dissipation capacity of the single structure of capillary network and protects the capillary wall from damage. Capillary network plane radiation air conditioning system generally adopts small circulation and large system mode, and adopts special solution as medium, which can avoid system blockage and facilitate control. In order to meet the requirements of higher comfort and avoid condensation, the room should also be equipped with humidity control and fresh air system. The production and application technology of capillary network has been highly monopolized by German enterprises before. Beijing Plaver Environmental Technology Co., Ltd. broke the monopoly of foreign enterprises, developed and produced domestic capillary network heat exchangers, and applied for a number of invention patents and utility model patents, which has entered the mass production stage.
In May, 2007, the product was tested in the Air Conditioning Institute of China Institute of Building Research (National Air Conditioning Equipment Quality Supervision and Inspection Center). Taking testing a node as an example, the results are as follows:
1, no leakage under the experimental pressure 1.5Mpa;
2. When the water supply temperature is 45℃, the return water temperature is 40℃, the reference temperature is 20℃, and △T=22.5℃, the heat dissipation per unit area of the sample is equivalent to QDR = 240.88 w/m2；;
3. When the water supply temperature is 15℃, the backwater temperature is 20℃, and the reference temperature is 26℃ and △T8.5℃, the cooling capacity per unit area of the sample is converted into Qdl= 122.84W/m2.
Thin tube use
Capillary tubes are generally used for small freon refrigeration devices below 20kW. Capillary tube is controlled by copper.
capillary tube
The length is 1~6m, and the inner diameter is 0.5~2mm. Through various combinations of length and pipe diameter, the requirements of refrigeration equipment with different working conditions and refrigeration capacity can be met. However, after the capillary tube is installed, it cannot change with the load. In order to make the refrigeration device run efficiently most of the time, it is extremely important to choose a representative design condition. ? [ 1]?
capillarity
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Definition: When an object with a small gap comes into contact with a liquid, the liquid rises or soaks along the gap in the case of infiltration, and falls along the gap in the case of non-infiltration. In the case of infiltration, the thinner the gap, the higher the liquid rises. This means that due to the difference of cohesion and adhesion, the liquid inside the tubule rises against gravity.
introduce
Capillary phenomenon (also known as capillary action) refers to the phenomenon that liquid rises or falls inside a thin tube because of the difference of cohesion and adhesion, overcoming gravity.
When an object with pores comes into contact with liquid, the liquid rises along the pores.
Capillary effect
The phenomenon of decline. When the adhesion between liquid and solid (pipe wall) is greater than the cohesion of liquid itself, capillary phenomenon (rising) will occur; On the contrary, when the adhesion between liquid and solid (pipe wall) is less than the cohesion of liquid itself, capillary phenomenon (decline) will occur. The liquid level is concave or convex when it is in the vertical thin tube, and the porous material can absorb the liquid. The appearance of capillary action is due to the viscosity of water-the characteristic that water molecules attach to other objects, which can be glass, cloth, organ tissue or soil. Mercury, on the other hand, has capillary phenomenon (falling) due to the strong cohesion between atoms.
The smaller the capillary, the less obvious the influence of air pressure on water absorption, so the smaller the capillary, the stronger the water absorption when it is perpendicular to the water surface. ? [2]?
influencing factor
The water absorption of the paper itself, the size and shape of the paper, and the level of water will all affect the capillary phenomenon and produce many different results. Moreover, the temperature of water will also affect the capillary phenomenon. The higher the water temperature, the faster the water rises, on the contrary, the slower it rises. Therefore, the characteristics of the liquid itself are also the main reasons that affect the capillary phenomenon. Moreover, the increase of water temperature will produce a lot of water vapor, so water vapor will also accelerate the capillary phenomenon. In addition, when the cohesion of liquid molecules is less than the attraction between them and paper (or other substances), capillary phenomenon (rising) will also occur. Different liquids or papers have different capillary phenomena. Mercury, for example, has capillary phenomenon (falling) because of the strong cohesion between atoms. ? [2]?
Common examples
Water absorbed by the roots of plants can rise through the vascular bundles in the stems.
Plant water absorption
Dip the paper towel into a glass of water, and the water will climb on the paper towel until it can't overcome the gravity of the earth. Because water is sticky, when the water in your cup splashes on the table, it will not flow to the ground, but form an arc-shaped small water stain on the table.
Production application
Although capillary action is very helpful for plants to absorb water, capillary phenomenon will also have a negative impact on agricultural production. There are many capillaries in the soil, and underground water often rises to the ground along these capillaries. If we want to preserve groundwater, we should hoe the soil on the ground, destroy the capillaries on the soil surface and reduce the evaporation of water.
When building a house, there are many thin capillaries in the compacted foundation, which will lead the moisture in the soil up and make the room moist. When building a house, spread linoleum on the foundation to prevent moisture caused by capillary phenomenon. ? [2]?
Capillary Electrophoresis
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Capillary electrophoresis (CE), also known as high performance capillary electrophoresis (HPCE), is a new liquid phase separation technology with capillary as separation channel and high voltage DC electric field as driving force. Capillary electrophoresis actually includes electrophoresis, chromatography and their cross contents, which makes analytical chemistry develop from micro-upgrade to nano-upgrade, and makes single cell analysis and even single molecule analysis possible. The separation and analysis of biomacromolecules, such as protein, which has been bothering us for a long time, has also made a new turn.
Capillary electrophoresis usually uses an elastic (polyimide) coated fused quartz tube with an inner diameter of 25-100μ m. The standard capillary has an outer diameter of 375μ m, and some tubes have an outer diameter of160μ m. The characteristics of the capillary are: small volume (the volume of a tube100cm× 75μ m is only 4.4μ l); Large side/cross-sectional area ratio, fast heat dissipation, and can withstand high electric field (100-1000 v/cm); Free solution, gel, etc. Can be used as a supporting medium; In solution medium, plane electroosmotic flow can be produced.
Therefore, capillary electrophoresis has the following advantages:
(1) The number of efficient pallets is between 105- 106 tablets /m, and when CGE is used, the number of pallets can reach more than 107 tablets /m;
(2) Rapid separation is generally completed within ten minutes;
(3) The sample volume required for microinjection is nL;
(4) Multi-mode can choose different separation modes according to needs, and only one instrument is needed;
(5) Economic experiments only consume a few milliliters of buffer, so the maintenance cost is very low;
(6) Automatic CE is a highly automated separation method at present.
The disadvantages of capillary electrophoresis are:
(1) Due to the small sample size, the preparation ability is poor;
(2) Due to the small capillary diameter and short optical path, some detection methods (such as ultraviolet absorption spectrometry) have low sensitivity;
(3) Electroosmosis will change with the change of sample composition, which will affect the separation reproducibility.
Understand? Good wishes!