Information about the sun

The celestial bodies in the universe are constantly moving, forming celestial bodies systems at all levels. For example, the moon revolves around the earth to form the earth-moon system, and the earth is the central celestial body in earth-moon system. The earth and other planets in the solar system revolve around the sun, which is the central celestial body in the solar system. The solar system is a small part of the Milky Way. In the Milky Way, there are over 200 billion stars like the sun.

Outside the Milky Way, there are about 654.38+billion celestial systems similar to the Milky Way, which we call extragalactic galaxies. The Milky Way and the extragalactic galaxy * * * together constitute the main galaxy. The total galaxy is the part of the universe that people can observe at present.

In order to understand the starry sky, people imagine the universe as a sphere with infinite radius, called the celestial sphere.

In order to understand the stars, people divide the celestial sphere into several regions, which are called constellations. For example, the Big Dipper is the main part of the constellation Ursa major. According to international regulations, the world is divided into 88 constellations. Every star belongs to a constellation. For example, Polaris is a star in Ursa minor.

Therefore, the solar system and constellation are completely different concepts and cannot be confused.

Supplement:

The origin of 12 constellation and 88 constellation

Constellation 88: In ancient times, people connected the scattered stars in the sky through imagination in order to facilitate navigation and observe the astronomical phenomena. Half of them were named in ancient times, and the naming method was based on the myths and forms of ancient civilizations (including the myths and epics of Mesopotamia, Babylon, Egypt and Greece). The other half (mostly in the night sky in the southern hemisphere) was named only in modern times, and is often named after navigation instruments. In ancient times, because of different regions, the way of "Lianliankan" was different! Now the world has unified the constellation map into 88 constellations and divided the sky into 88 regions.

12 constellation: what we usually call "constellation" refers to "sun constellation"; That is to say, people on the earth are the center, and at the same time, we can see which constellation the sun is in orbit (Greek zodiac: meaning ~ circle made by animals, also known as "zodiac"), so we can say what constellation that person is. More than 2000 years ago, the Greek astronomer Hipparchus (190 ~ 120 BC) divided the ecliptic into twelve segments, with spring divided into zero, and every 30 degrees from the vernal equinox (that is, the zero degree of the ecliptic) as a palace, taking the main constellations contained in each palace at that time. There are twelve constellations in all. Babies born when the earth moves to every fraction (constellation) will always have some similar characteristics when they grow up, including behavioral characteristics. By connecting these associations (rich imagination and creativity) in series, these constellations are visualized; It also adds the color of myth and becomes an important part of culture (mainly Greek and Roman mythology). This set of numerology has been developed and circulated for at least five thousand years, represented by these twelve constellations respectively. But these constellations do not represent a certain "star", but can only be regarded as "representative symbols of the same name".

A little information about 12 constellation:

1. Sun (Sun)

A circle symbolizing the spirit, with a dot in it, represents the bud of life in chaos.

● The sun guards Leo; The meaning of personal birth chart is self-expression. As the source of all the stars, it affects personality. Looking at Leo from the sun, we can find its love and photometric characteristics; In addition, the sun is often compared to an emperor, which is also related to Leo's love of face and the wind of kings.

Does this mean that the sun belongs to Leo in 12 constellation? -American police)

A little information about 88 constellations:

Andromeda

Andromeda has already mentioned it when talking about the autumn quadrangle (see the constellation introduction of Pegasus). The alpha star that constitutes this quadrilateral is the brightest star in Andromeda, which extends northeast from the diagonal line from Alpha Pegasus to Alpha Andromeda in the quadrilateral, and the three bright stars of Andromeda (except δ is 3m, the other two are 2m stars) are almost all on this extension line. Further on, you will meet the great spirit of Perseus. Daling V, Perseus α and Andromeda γ form a right triangle.

This Andromeda gamma star is a binary star, in which the main star is an orange star with a length of 2.3m and the companion star is a yellow star with a length of 5.1m.. Interestingly, this companion star is a "chameleon", which changes from yellow and gold to orange and blue, just like a clever magician.

Andromeda's most famous celestial body is probably the Big Nebula. Near Andromeda υ, on a clear moonless night, we can see a small blue and white cloud, which is the Andromeda Nebula. This nebula was discovered by astronomers as early as 16 12, but it was not until the 1920s that American astronomer Hubble made it clear that it was completely different from the nebula in Sagittarius. It is a large galaxy 2.2 million light years away from us, so its correct name should be "Andromeda Extragalactic Galaxy".

Andromeda, an extragalactic galaxy, has a diameter of 65.438+0.7 billion light years and contains more than 300 billion stars. Much like our Milky Way, it is also a vortex, and there are also many variable stars, clusters and nebulae. Interestingly, there are two small galaxies beside them, which together form a triple galaxy. (Nothing about the sun-American police)

Le Signe du Lion

Once I mentioned Leo when I introduced Capricorn and Virgo in the spring night sky. The constellations of beta star in Leo, arcturus in Capricorn and Virgo form an important "Spring Triangle" in spring night.

Leo is also the zodiac sign. Due to precession, the apparent motion of the sun just passed Leo in June every year more than 4,000 years ago. It's June, and the obvious movement of the sun has reached between Taurus and Gemini. At that time, people in the ancient Persian Gulf country of Chaldea thought that the sun got a lot of heat from Leo, so the weather became hot. The ancient Egyptians felt the same way, because at this time of year, many lions moved to the Nile Valley for the summer.

Ancient Egypt worshipped Leo very much. It is said that the famous Sphinx is shaped by the body of a lion and the head of a maid. The star of Leo was also highly valued in ancient China, and was called the God of the Yellow Emperor and Xuanyuan.

After we found the beta star of Leo through the spring triangle on a spring night, a big star to its east was all Leo's. In Leo, delta, theta and beta stars form a remarkable triangle, which is the lion's back and tail. These six stars from ε to α form the shape of a sickle, which is also like a reverse question mark. This is the lion's head. When the Polaris connecting the constellation Ursa major (that is, the two stars in the spoon mouth) extends in the opposite direction to Polaris, you can find it. Alpha star is called Xuanyuan XIV in China, and its apparent magnitude is1.35m. It is the brightest star in Leo, and it is the 2nd1in the whole day. It forms an isosceles triangle with arcturus and arcturus, and can be found by extending the δ and γ stars of Ursa Major ten times. In ancient times, navigators often used it to determine the position of ships in the sea, so Alpha Leo was awarded the title of "one of the nine navigation planets".

Leo's Xuanyuan XIV is located near the ecliptic, which is about 90 degrees away from the four bright stars Taurus, Scorpio Antares and Nanyu's Beiluoshimen. They are called the "four heavenly kings" of the zodiac.

Every year in June165438+1mid-October, especially in the nights of June 14 and June 15, a large number of meteors will appear near ζ star with question marks written on Leo. This is the famous Leonid meteor shower. It peaks every 33 years. As early as 93 1 year, it was recorded in China in the Five Dynasties. At the peak of 1833, meteors exploded near zeta star like fireworks, with tens of thousands of them every hour. Therefore, the next night, a farmer hurried outside to see if all the stars in the sky had fallen out. Can you explain that the sun belongs to Leo? -American police)

Summary: Does the sun belong to Leo in 12 and 88 constellations? I don't know much about constellations. Go to the following website and have a look again, or ask an expert.

References:

/BBS/archive/o _ t/t _ 36 182/start _ 0//art/twdg/index 4 . htm

solar cell

Introduction Solar energy is an inexhaustible renewable energy source for human beings, and it is also a clean energy source, which will not produce any environmental pollution. Effective use of solar energy; The photoelectric utilization of ocean energy is the fastest developing and most dynamic research field in recent years, and it is also one of the most striking projects. Therefore, people have developed solar cells. The manufacture of solar cells is mainly based on semiconductor materials, and its working principle is that photoelectric materials absorb light energy and then undergo photoelectric conversion reaction. According to the different materials used, solar cells can be divided into: 1, silicon solar cells; 2. Batteries made of inorganic salts, such as gallium arsenide III-V compounds, cadmium sulfide, copper indium selenium and other multicomponent compounds; 3. Large solar cells made of functional polymer materials; 4. Nanocrystalline solar cells, etc. No matter what kind of material is used as the battery, the general requirements for solar cell materials are: 1, and the band gap of semiconductor materials should not be too wide; ② High photoelectric conversion efficiency: 3. The material itself does not pollute the environment; 4. The material is convenient for industrial production and has stable performance. Based on the above considerations, silicon is the most ideal material for solar cells, which is also the main reason why solar cells are mainly made of silicon. However, with the continuous development of new materials and related technologies, solar cells based on other village materials show more and more attractive prospects. This paper briefly introduces the types and research status of solar cells, and discusses the development and trend of solar cells. 1 silicon solar cell 1. 1 monocrystalline silicon solar cell Among silicon solar cells, monocrystalline silicon solar cells have the highest conversion efficiency and the most mature technology. High-performance monocrystalline silicon battery is based on high-quality monocrystalline silicon material and related heating processing technology. At present, the electrical grounding technology of monocrystalline silicon is close to maturity. In the production of batteries, technologies such as surface texturing, passivation of emitter region and zoning doping are generally adopted. The developed batteries mainly include planar monocrystalline silicon batteries and trench buried gate electrode monocrystalline silicon batteries. Improving the conversion efficiency mainly depends on the surface microstructure treatment and zoning doping process of monocrystalline silicon. In this respect, Flawn Hof Solar Energy System Research Institute maintains a world-leading level. In this study, the surface of the battery is textured by lithography and photography to make an inverted pyramid structure. And put a 13nm on the surface. The thick oxidation passivation layer combined with two anti-reflective coatings improves the aspect ratio of grid by improved electroplating process: the conversion efficiency of the battery made by the above method exceeds 23%, but the maximum value can reach 23.3%. The conversion efficiency of large-area (225cm2) single crystal solar cells prepared by Kyocera Corporation is 19.44%, and China Beijing Solar Research Institute is also actively engaged in the research and development of high-efficiency crystalline silicon solar cells. The conversion efficiency of planar high efficiency monocrystalline silicon battery (2cm×2cm) is 19.79%, and that of trench buried gate electrode crystalline silicon battery (5cm×5cm) is 8.6. The conversion efficiency of monocrystalline silicon solar cell is undoubtedly the highest, and it still occupies a dominant position in large-scale application and industrial production. However, due to the influence of the price of monocrystalline silicon material and the corresponding complicated battery technology, the cost of monocrystalline silicon remains high, and it is very difficult to greatly reduce its cost. In order to save high-quality materials and find alternative products of monocrystalline silicon cells, thin-film solar cells have been developed, among which polycrystalline silicon thin-film solar cells and amorphous silicon thin-film solar cells are typical representatives. 1.2 polycrystalline silicon thin film solar cell The usual crystalline silicon solar cell is made on a high-quality silicon wafer with a thickness of 350 ~ 450μ m, which is sawed from a drawn or cast silicon ingot. More silicon material is actually consumed. In order to save materials, people began to deposit polycrystalline silicon thin films on cheap substrates in the mid-1970s, but due to the grain size of the grown silicon films, they failed to make valuable solar cells. In order to obtain films with large grain size, people have never stopped studying and put forward many methods. At present, chemical vapor deposition (CVD) is widely used to prepare polycrystalline silicon thin film batteries, including low pressure chemical vapor deposition (LPCVD) and plasma enhanced chemical vapor deposition (PECVD). In addition, liquid phase epitaxy (LPPE) and sputtering deposition can also be used to prepare polycrystalline silicon thin film batteries. Chemical vapor deposition mainly uses SiH2Cl2, SiHCl3, Sicl4 or SiH4 as reaction gases, which react in a certain protective atmosphere to generate silicon atoms and deposit them on heated substrates. The substrate material is usually silicon, silicon dioxide, silicon nitride, etc. However, it is found that it is difficult to form large grains on non-silicon substrates, and it is easy to form gaps between grains. The solution to this problem is to deposit a thin amorphous silicon layer on the substrate by LPCVD, then anneal the amorphous silicon layer to obtain larger grains, and then deposit a thick polysilicon film on the seed crystal. Therefore, recrystallization technology is undoubtedly a very important link. At present, the main technologies used are solid-state crystallization and zone melting recrystallization. In addition to recrystallization process, polycrystalline silicon thin film battery adopts almost all the processes for preparing monocrystalline silicon solar cells, which obviously improves the conversion efficiency of the prepared solar cells. The conversion efficiency of polycrystalline silicon cells prepared by Freiburg Solar Energy Research Institute in Germany on FZ Si substrate is 19%, and that of Mitsubishi Corporation in Japan is 16.42%. The principle of liquid phase epitaxy (LPE) is to melt the silicon in the matrix and lower the temperature to precipitate the silicon film. The efficiency of the battery prepared by LPE of Astropower Company in the United States reached 12.2%. Chen Zheliang of China Photoelectric Development Technology Center used liquid phase epitaxy to grow silicon grains on metallurgical grade silicon wafers, and designed a new type of solar cell similar to crystalline silicon thin-film solar cell, called "silicon grain" solar cell, but no reports about its performance have been seen. The amount of silicon used in polycrystalline silicon thin film battery is far less than that of monocrystalline silicon, so there is no problem of efficiency decline, and it can be prepared on cheap substrate materials. Its cost is much lower than that of monocrystalline silicon battery, but its efficiency is higher than that of amorphous silicon thin film battery. Therefore, polycrystalline silicon thin film batteries will soon occupy a dominant position in the solar energy market. 1.3 amorphous silicon thin film solar cell Two key issues in developing solar cells are: improving conversion efficiency and reducing cost. Amorphous silicon thin film solar cells have attracted people's attention and developed rapidly because of their low cost and convenience for mass production. In fact, as early as the early 1970s, Carlson and others had started the research and development of amorphous silicon batteries, and in recent years, their research and development work has developed rapidly. At present, many companies in the world are producing this battery product. Although amorphous silicon is a good solar cell material, its optical band gap is 1.7eV, which makes the material itself insensitive to the long-wave region of solar radiation spectrum, thus limiting the conversion efficiency of amorphous silicon solar cells. In addition, its photoelectric efficiency will decrease with the extension of illumination time, which is the so-called photo-induced attenuation S-W effect, which makes the battery performance unstable. The solution to these problems is to prepare laminated solar cells, which are made by depositing one or more P-i-n daughter cells on the prepared P, I and N single-junction solar cells. The key problems to improve the conversion efficiency and solve the instability of single-junction solar cells are as follows: ① it combines materials with different band gaps to improve the spectral response range; (2) The I layer of the top battery is thin, and the intensity of the electric field generated by illumination changes little, which ensures the extraction of photogenerated carriers in the I layer; (3) The carrier generated by the bottom battery is about half that of the single battery, and the photo-induced fading effect is reduced; (4) Each sub-cell of the laminated solar cell is connected in series. There are many methods to prepare amorphous silicon thin film solar cells, including reactive sputtering, PECVD, LPCVD and so on. The reactant gas is SiH4 diluted with H2, and the substrate is mainly glass and stainless steel sheets. Amorphous silicon thin films can be made into single junction cells and laminated solar cells by different cell processes. At present, two major advances have been made in the research of amorphous silicon solar cells: the conversion efficiency of the first and third stacked amorphous silicon solar cells reached 13%, setting a new record; The annual production capacity of the second and third-tier solar cells reaches 5MW. The maximum conversion efficiency of single-junction solar cells manufactured by United Solar Corporation (VSSC) is 9.3%, and the maximum conversion efficiency of three-band-gap three-layer solar cells is 13%, as shown in Table 1. The maximum conversion efficiency is achieved on a small area (0.25cm2) battery. It is reported that the conversion efficiency of single-junction amorphous silicon solar cells exceeds 65,438+02.5%. Academia Sinica of Japan has adopted a series of new measures, and the conversion efficiency of amorphous silicon solar cells is 13.2%. There is little research on amorphous silicon thin film batteries, especially laminated solar cells in China. Geng Xinhua of Nankai University and others have prepared A-Si/A-Si laminated solar cell with an area of 20X20cm2, conversion efficiency of 8.28% and aluminum back electrode by using industrial materials. Amorphous silicon solar cells have great potential because of their high conversion efficiency, low cost and light weight. But at the same time, its low stability directly affects its practical application. If we can further solve the stability problem and improve the conversion rate, then amorphous silicon solar cells will undoubtedly be one of the main development products of solar cells. 2 Multi-compound thin film solar cells In order to find a substitute for monocrystalline silicon cells, people have developed solar cells made of other materials except polycrystalline silicon and amorphous silicon films. These mainly include gallium arsenide III-V compounds, cadmium sulfide, cadmium sulfide and copper indium selenium thin film batteries. Among the above batteries, polycrystalline thin-film batteries of cadmium sulfide and cadmium telluride have higher efficiency than amorphous silicon thin-film solar cells, lower cost than monocrystalline silicon batteries, and are easy for mass production. However, cadmium is highly toxic and will cause serious pollution to the environment. Therefore, it is not the most ideal substitute for crystalline silicon solar cells for gallium arsenide III-V compounds and copper indium selenium thin film cells, and people pay more attention to it because of its high conversion efficiency. GaAs belongs to group III-V compound semiconductor materials, and its energy gap is 1.4eV, which is just the value of high solar absorption rate, so it is an ideal battery material. MOVPE and LPE technologies are mainly used to prepare III-V compound thin film batteries such as GaAs, among which the preparation of GaAs thin film batteries by MOVPE method is affected by many parameters such as substrate dislocation, reaction pressure, III-V ratio, total flow rate and so on. Besides GaAs, other III-V compounds have been developed, such as Gasb, GaInP and other battery materials. From 65438 to 0998, the conversion efficiency of GaAs solar cells manufactured by Frejborg Solar System Research Institute was 24.2%, setting a European record. The conversion efficiency of GaInP battery prepared for the first time is 14.7%. See Table 2. In addition, the institute also used stacked structure to prepare GaAs and Gasb batteries. This battery is composed of two independent batteries stacked, with GaAs as the upper battery and Gasb as the lower battery. The battery efficiency reached 3 1. 1%. Copper indium selenium CuInSe2 is abbreviated as CIC. The energy of cis-substances is reduced to 1. Lev, suitable for photoelectric conversion of sunlight. In addition, there is no photodegradation problem in CIS thin film solar cells. Therefore, the use of CIS as a thin film solar cell material with high conversion efficiency has also attracted people's attention. The preparation of CIS battery film mainly includes vacuum evaporation and selenization. Vacuum evaporation method uses evaporation sources of copper, indium and selenium respectively, and selenization method uses H2Se laminated film for selenization, but it is difficult to obtain CIS with uniform composition by this method. The conversion efficiency of CIS thin film battery has developed from 8% in the 1980s to about 15% at present. The photoelectric conversion efficiency of gallium-doped CIS battery developed by Matsushita Electric Co., Ltd. in Japan is 15.3% (area 1cm2). 1995, the American Institute of Renewable Energy developed a CIS solar cell with a conversion efficiency of 17. L%, which is by far the highest conversion efficiency in the world. It is estimated that by the year 2000, the conversion efficiency of CIS batteries will reach 20%, which is equivalent to that of polysilicon solar cells. CIS, as a semiconductor material for solar cells, has the advantages of low price, good performance and simple process, and will become an important direction for the development of solar cells in the future. The only problem is the source of the materials. Because indium and selenium are relatively rare elements, the development of such batteries is bound to be limited. 3 polymer multilayer modified electrode solar cell It is a research direction of solar cell manufacturing to replace inorganic materials with polymers in solar cells. Its principle is to make use of different redox potentials of different redox polymers to make multilayer composite on the surface of conductive materials (electrodes) to make unidirectional conductive devices similar to inorganic P-N junctions. The inner layer of an electrode is modified with a polymer with a lower reduction potential, while the outer layer has a higher reduction potential, and the electron transfer direction can only be transferred from the inner layer to the outer layer; The modification of the other electrode is just the opposite, and the reduction potential of the two polymers on the first electrode is higher than that of the latter two polymers. When two modified electrodes are put into electrolytic wave containing photosensitizer, the electrons generated after the photosensitizer absorbs light are transferred to the electrode with lower reduction potential, and the electrons accumulated on the electrode with lower reduction potential cannot be transferred to the outer polymer, but can only return to the electrolyte through the electrode with higher reduction potential through the external circuit, thus generating photocurrent in the external circuit. Organic materials are of great significance to the large-scale utilization of solar energy and the provision of cheap electricity because of their good flexibility, easy manufacture, wide sources of materials and low cost. However, the research on the preparation of solar cells from organic materials has just begun, and it can not be compared with inorganic materials, especially silicon cells, in terms of service life and battery efficiency. Whether it can be developed into a product with practical significance needs further research and exploration. 4 Nanocrystalline Chemical Solar Cells Among solar cells, silicon-based solar cells are undoubtedly the most mature, but due to the high cost, they are far from meeting the requirements of large-scale popularization and application. For this reason, people have been exploring battery technology, new materials and thin films, and the newly developed nano-TiO2 _ 2 crystal chemical energy solar cell has attracted the attention of scientists at home and abroad. Since Gratzel, a professor in Switzerland, successfully developed nano-TiO2 _ 2 _ 2 chemical solar cells, some domestic units are also conducting research in this field. Nanocrystalline chemical solar cells (hereinafter referred to as NPC cells) are formed by modifying a semiconductor material with a band gap and assembling it on another semiconductor material with a large band gap. The narrow band gap semiconductor material uses organic compound sensitizing dyes such as transition metal Ru and Os, and the large band gap semiconductor material is nano-polycrystalline TiO2 and made into electrodes. In addition, an appropriate redox electrolyte is selected for NPC batteries. The working principle of nanocrystalline TiO _ 2: dye molecules absorb solar energy and jump to excited state, and the excited state is unstable. Electrons are quickly injected into the adjacent TiO _ 2 conduction band, and the electrons lost in the dye are quickly compensated from the electrolyte. The electricity entering the TiO _ 2 conduction band finally enters the conductive film, and then the photocurrent is generated through the outer loop. Nanocrystalline TiO2 _ 2 solar cells have the advantages of low cost, simple process and stable performance. Its photoelectric efficiency is stable above 10%, its manufacturing cost is only1/5 ~1/and its service life can reach more than 20 years. However, since the research and development of this battery has just started, it is estimated that it will gradually enter the market in the near future. 5 Development trend of solar cells As can be seen from the above discussion, as materials of solar cells, III-V compounds and CIS are all made of rare elements. Although the conversion efficiency of solar cells made of them is very high, from the perspective of material sources, this kind of solar cells cannot occupy a dominant position in the future. However, the other two types of batteries, nanocrystalline solar cells and polymer modified electrodes, have some problems, such as their research has just started, their technology is not very mature, and their conversion efficiency is still relatively low. These two kinds of batteries are still in the exploration stage, and it is impossible to replace solar cells in a short time. Therefore, from the perspective of conversion efficiency and material source, the focus of future development is still silicon solar cells, especially polycrystalline silicon and amorphous silicon thin film cells. Because of the high conversion efficiency and relatively low cost, polycrystalline silicon and amorphous silicon thin film batteries will eventually replace monocrystalline silicon batteries and become the leading products in the market. Improving conversion efficiency and reducing cost are two main factors to be considered when preparing solar cells. It is difficult to further improve the conversion efficiency for the current silicon-based solar cells. Therefore, in addition to continuing to develop new battery materials, the focus of future research should also focus on how to reduce costs. The existing solar cells with high conversion efficiency are made on high-quality silicon wafers, which is the most expensive part of manufacturing silicon solar cells. Therefore, it is particularly important to reduce the cost of the substrate under the condition of ensuring high conversion efficiency. It is also an urgent problem to be solved in the future development of solar cells. Recently, foreign countries have used some technologies to make silicon strips into the substrate of polycrystalline silicon thin film solar cells, in order to achieve the purpose of reducing costs, and the effect is still ideal.