How will the gas change if the temperature continues to rise? Scientists tell us that at this time, the atoms that make up the molecule split and form independent atoms. For example, a nitrogen molecule will split into two nitrogen atoms. We call this process the dissociation of gas molecules. If the temperature is further raised, the electrons in the atom will be stripped from the atom and become a positively charged nucleus and negatively charged electrons. This process is called ionization of the atom.
Edit this paragraph Introduction
Plasma state refers to the attraction of electrons in the atoms of matter to break away from the nucleus at high temperatures, causing the matter to exist in the state of positively and negatively charged particles.
Edit this paragraph for a detailed introduction to plasma
The plasma state is a ubiquitous state. Most of the luminous planets in the universe have high internal temperatures and pressures, and the material inside these planets is almost always in a plasma state. Solid, liquid, and gaseous materials can only be found in dim planets and scattered interstellar matter. Plasma has a wide range of uses. It has very important application value from our daily life to industry, agriculture, environmental protection, military, aerospace, energy, celestial bodies, etc. The plasma state refers to the attraction of the electrons in the atoms of the substance to break away from the nucleus at high temperatures, causing the substance to exist in the state of positively and negatively charged particles. In our daily life, we encounter various substances. According to their state, they can be divided into three major categories, namely solid, liquid and gas. For example, steel is a solid, water is a liquid, and oxygen is a gas. Any substance can transform between these three states under certain conditions. Taking water as an example, under a standard atmospheric pressure, when the temperature drops below 0°C, water begins to turn into ice. When the temperature rises to 100°C, water will boil and turn into water vapor. If the temperature continues to rise, what will happen to the gas? Scientists tell us that at this time, the atoms that make up the molecule split and form independent atoms. For example, a nitrogen molecule will split into two nitrogen atoms. We call this process the dissociation of gas molecules. If the temperature is further raised, the electrons in the atom will be stripped from the atom and become a positively charged nucleus and negatively charged electrons. This process is called ionization of the atom. When this ionization process occurs frequently and the concentration of electrons and ions reaches a certain value, the state of the material changes fundamentally, and its properties become completely different from those of gases. In order to distinguish it from the three states of solid, liquid and gas, we call this state of matter the fourth state of matter, also called the plasma state. Around us, we often see plasma-like matter. Traces of it can be found in fluorescent lamps and neon lamps, and in the dazzling incandescent arcs. In addition, wonderful plasma states can also be found in the ionosphere around the Earth, in beautiful aurorae, flash discharges in the atmosphere and the tails of meteors.
Edit this paragraph Plasma state
In the vast and endless space of the universe, plasma state is a ubiquitous state. Most of the luminous planets in the universe have high internal temperatures and pressures, and the material inside these planets is almost always in a plasma state. Solid, liquid, and gaseous materials can only be found in dim planets and scattered interstellar matter. Around us, we often see plasma-like matter. Traces of it can be found in fluorescent lamps and neon lamps, and in the dazzling incandescent arcs. In addition, wonderful plasma states can also be found in the ionosphere around the Earth, in beautiful aurorae, flash discharges in the atmosphere and the tails of meteors.
Concept
When this ionization process occurs frequently and the concentration of electrons and ions reaches a certain value, the state of the substance changes fundamentally, and its properties also change. Become completely different from gas. In order to distinguish it from the three states of solid, liquid and gas, we call this state of matter the fourth state of matter, also called the plasma state.
Features
Substances in the plasma state have properties similar to those in the gaseous state, such as good fluidity and diffusion. However, since the basic constituent particles of plasma are ions and electrons, it also has many properties that are different from gaseous states, such as good electrical conductivity and thermal conductivity.
In particular, according to scientific calculations, the specific heat of plasma is directly proportional to the temperature. The specific heat of plasma at high temperatures is often hundreds of times that of gas.
Uses
What are the uses of plasma? oh! Its uses are very versatile. It has very important application value from our daily life to industry, agriculture, environmental protection, military, medicine, aerospace, energy, celestial bodies, etc.
Plasma cutting machine
Plasma cutting machine is used in industry. Plasma cutting can be used with different working gases to cut various oxygen cutting machines
It has better cutting effect on metals that are difficult to cut, especially non-ferrous metals (stainless steel, aluminum, copper, titanium, nickel); its main advantage is that when cutting metals with small thickness, plasma cutting speed is fast, especially when cutting ordinary carbon When cutting steel sheets, the speed can reach 5 to 6 times that of oxygen cutting, the cutting surface is smooth, the thermal deformation is small, and there is almost no heat-affected zone. An important study is high-temperature plasma and controlled thermonuclear fusion reactions: If the lightest element in matter, such as hydrogen isotope deuterium, is used to form a high-temperature plasma of tens of millions of degrees Celsius, then these atomic nuclei will undergo nuclear reactions. ． As a result, huge amounts of energy will be released, and scientists call it a thermonuclear fusion reaction. The hydrogen bomb is such an explosive thermonuclear fusion reaction. However, humans hope to have a thermonuclear fusion reaction that slowly releases energy and can generate electricity to build an "artificial small sun". However, this goal has not yet been achieved.
Condensed to form a slender arc column, the temperature can reach 18000-24000K, which is higher than the conventional free arc, such as argon arc welding only reaches 5000-8000K. Because plasma arc has the characteristics of slender arc column and high energy density, it is widely used in the field of welding. The plasma welding machine has the following obvious characteristics: 1. High-efficiency and high-quality plasma welding process method, which uses the ability of the plasma arc to penetrate good small holes to ensure single-sided welding and double-sided forming while maximizing the welding speed, which is the most efficient TIG welding 5~7 times. 2. Using plasma and TIG hybrid welding, plasma primer and TIG cover can more effectively improve welding quality and efficiency. The free arc of TIG welding has good covering ability, and when combined with an appropriate amount of filler metal remelting, it can achieve a beautiful front-facing effect, which is 1.3-1.5 times more efficient than single-gun plasma welding. 3 Mainly targeted at thin-walled 3~10mm stainless steel plates Longitudinal circumferential seam welding of containers made of materials such as , titanium alloy plates, etc. 4 For stainless steel plates with a wall thickness of less than 8 mm and titanium alloy plates with a wall thickness of less than 10 mm, single-sided welding and double-sided forming can be achieved without beveling
Edit this section Stealth aircraft
Another important application is that some special chemical elements form a low-temperature plasma whose macroscopic temperature is not high, but the electron temperature can reach tens of thousands of degrees Celsius. At this time, special interactions will occur between substances. Chemical reactions can therefore be used to develop new materials. For example, coating tools such as drill bits with a thin layer of titanium nitride to improve the strength of the tools, manufacturing solar cells, and coating the surface of aircraft with a material that specifically absorbs radar waves can avoid radar tracking (i.e., stealth aircraft). ...These are called plasma thin film technologies. In addition, plasma can also be used to remove sulfur from smoke, use plasma to irradiate seeds to increase crop yields, develop large-screen plasma TVs, and develop plasma rocket engines to travel to distant universes such as Mars... Plasma The applications are really numerous. In addition, plasma has also received attention in medical surgical treatment. For example, plasma low-temperature ablation surgery, which has become popular in recent years, is used to treat rhinitis, pharyngitis, snoring and other diseases.
The principle of plasma cryogenic ablation surgery is to form a thin plasma layer between the electrode and the tissue. The ions in the layer are accelerated by the electric field and transfer the energy to the tissue. At low temperature (40℃-70℃), the molecular bonds between cells are opened and the target is released. The cells in the tissue decompose into carbohydrates and oxides, causing the diseased tissue to liquefy and ablate, which is called plasma (not a thermal effect), thereby achieving the effect of reducing the volume of the target tissue.
Edit this paragraph Plasma display screen and TV
Plasma color TV PDP (Plasma Display Panel) is a wall-mounted plasma TV that injects mixed gas between two ultra-thin glass plates
A device that uses phosphor to emit light and image by applying voltage. A mixed gas is filled between thin glass plates, a voltage is applied to generate ion gas, and then the plasma gas is discharged and reacts with the phosphor in the substrate to produce a color image. Plasma color TV, also known as "wall-mounted TV", is not affected by magnetism and magnetic fields. It has the advantages of slim body, light weight, large screen, bright colors, clear picture, high brightness, low distortion and space saving. Plasma is a new generation display device using plasma flat screen technology that has developed rapidly in recent years. There are two types of products currently on the market, one is plasma display screen and the other is plasma TV. Both are essentially the same. There isn't much of a difference, the only difference is the lack of a built-in TV reception tuner. Since PDP was mainly developed for commercial display purposes in the early stages of development, there are still many PDPs that do not have built-in TV reception tuners, which means they cannot directly receive TV signals. Therefore, if you choose this product, you can only use other equipment such as a satellite decoder or video recorder to double as a TV signal tuning receiver, or you can purchase an additional TV receiver. Nowadays, plasmas have begun to be designed and produced for home users. Some of the plasmas currently produced have built-in TV receivers. These models are pre-equipped with RF radio frequency connection terminals and can directly play TV programs. Most domestic PDPs have built-in TV receivers, such as many products from Hisense, SVA and TCL. As for foreign manufacturers, some products use external TV receivers, and some products use built-in TV receivers. PDPs with external TV receivers are generally called plasma displays, and PDPs with built-in TV receivers are called plasma TVs. When purchasing, you should ask whether it has a TV reception function. Plasma display screen PDP is a display device that utilizes gas discharge. This screen uses a plasma cavity as a light-emitting element. A large number of plasma chambers are arranged together to form a screen. The screen body of the plasma display screen is composed of two glass plates several hundred microns apart, which are isolated from the air. Each plasma cavity is filled with inert gases such as neon and xenon, and the gas in the plasma cavity is sealed between the two layers of glass. Ultraviolet light is produced, thereby stimulating the red, green and blue primary color phosphors on the flat panel display to emit visible light. Each ion cavity acts as a pixel and its working mechanism is similar to that of an ordinary fluorescent lamp. The combination of light and dark and color changes of these pixels produces images of various grayscales and colors, and TV color images are synthesized by the light emitted by individual pixels.
Features
Compared with traditional CRT TVs, the most prominent feature of PDP TVs is that they are “big and thin”. Other features include: (1) Thin and light structure. Since the PDP display module is thin and light, it determines the overall structural characteristics of the display screen. At the same time, the increase in display size does not require a corresponding increase in the thickness of the screen body. (2) Wide viewing angle. PDP can achieve the same wide viewing angle as CRT, more than 160 degrees up, down, left, and right. The viewing angle of liquid crystal (LCD) is generally about 120 degrees in the horizontal direction, and even less in the vertical direction. (3) Anti-electromagnetic interference. Due to differences in display principles, electromagnetic interference from the outside, such as motors, speakers, etc., has almost no impact on the PDP image. In contrast, CRT is much more affected by electromagnetic fields. (4) Flat images without distortion. The RGB grid of the PDP is evenly distributed on the plane, while the inner surface of the flat CRT is not flat, which will cause typical pincushion distortion.
And when the local brightness of the picture is uneven, CRT will often produce corresponding image distortion, while PDP does not have this phenomenon. (5) There are no convergence and focus problems. Plasma TVs are high-tech and cutting-edge electronic products that are relatively unfamiliar to many customers. Many people are cautious when using them because they do not understand its principles, so they cannot fully enjoy the enjoyment brought by plasma TVs. In fact, the service life of plasma TVs is about twice that of ordinary TVs. If the service life of an ordinary TV is 10 years, then plasma can be used for about 20 years, and plasma TV is superior to ordinary TV in many aspects such as display, color, appearance, etc., so plasma TV is the development of future TV direction.
Working principle
It is a display technology that uses gas discharge, and its working principle is very similar to that of fluorescent lamps. It uses plasma tubes as light-emitting elements. Each plasma tube on the screen corresponds to a pixel. The screen uses glass as the substrate. The substrates are spaced at a certain distance and are air-tightly sealed around them to form discharge spaces. The discharge space is filled with mixed inert gases such as neon and xenon as the working medium. The luminescence principle of PDP (the operating principle of plasma display screen)
The inner surfaces of two glass substrates are coated with metal oxide conductive films as excitation electrodes. When a voltage is applied to the electrode, a plasma discharge occurs in the mixed gas in the discharge space. The gas plasma discharge generates ultraviolet light, which excites the fluorescent screen, and the fluorescent screen emits visible light to display an image. When using a fluorescent screen coated with phosphors of three primary colors (also called three primary colors), ultraviolet light excites the fluorescent screen, and the light emitted by the fluorescent screen appears in the three primary colors of red, green, and blue. When each primary color unit achieves 256 levels of grayscale and then mixes colors, color display is achieved. Plasma display technology can be divided into two categories according to its working method: DC-type PDP, in which the electrodes are in direct contact with the gas, and AC-type PDP, in which the electrodes are covered with a dielectric layer. There are three main types of color PDP currently being researched and developed: single substrate type (also known as surface discharge type) AC PDP, dual type (also known as opposite discharge type) AC PDP and pulse storage DC PDP.
Edit this paragraph Plasma Surgery System
"Plasma" technology uses a specific ultra-low frequency 100Khz electric energy to excite the medium (Nacl) to generate plasma, and the high-speed charged particles in the plasma Directly breaks molecular bonds, cracking and vaporizing proteins and other tissues into low molecular weight gases such as H2, O2, CO2, N2 and methane. Under ordinary high-frequency 500-4000KHz changeable electric fields, on the one hand, particles cannot obtain sufficient acceleration time and are in a state of reciprocating oscillation; on the other hand, the increased molecular friction at high frequencies will produce a strong thermal effect, and the higher the frequency, the greater the heat generation. many. However, under a low-frequency stable electric field of 100KHz, particles will gain a longer acceleration time, eventually forming high-speed charged particles with greater kinetic energy, directly breaking molecular bonds. In addition, due to the low frequency, the frictional heat generation between molecules is greatly reduced compared to high frequency, so that cutting, ablation, hemostasis and other processes can be completed within 40℃~70℃, thereby achieving minimally invasive effects. Electrosurgical equipment has gone through the development stages of "electrosurgery" - "ordinary radio frequency" - "plasma radio frequency", from low to high. "Plasma" technology has completely changed the "thermal energy" working method of traditional "radio frequency" with direct "vaporization" working method. Tissue vaporization at 40℃~70℃ has replaced the traditional "cutting", "hemostasis" and other processes. The burn and destruction effect of high-temperature pile tissue greatly reduces the trauma during the operation. The minimally invasive effect produced by "plasma" technology in clinical treatment is the trend of future medical development.