Why do electric fans, washing machines, refrigerators and other household appliances mostly use three-wire plugs? What is the difference between a three-wire plug and a three-phase plug?
Three-phase electrical appliances refer to three different live wires, and the voltage between each two wires is 380 volts. They are generally used in power systems and are more common in industrial electricity consumption. Single-phase power supply is generally used in household appliances, and its three wires are live wire, neutral wire and ground wire. The voltage between the live wire and the neutral wire is 220 volts, so this is not three-phase electricity, and its plug socket is not a three-phase plug socket. The grounding wire is to ensure safety.
Fruit with antihypertensive effect
Hawthorn; Hawthorn can dilate blood vessels and lower blood pressure and cholesterol. You can choose 10 wild hawthorn (fresh is better), mash it with 30 grams of white sugar, and take it after decocting in water, which has a good effect of lowering blood pressure and invigorating stomach.
Bananas; Bananas contain a variety of vitamins, which can clear away heat and lower blood pressure and can be eaten regularly. It is also effective to decoct with 30~60 grams of banana peel or fruit stalk. Take a proper amount of plantain flowers and take them with water, and the curative effect is better.
Water chestnut; It has the effect of clearing away heat and lowering blood pressure. You can use fresh water chestnut (washed, mud removed) and jellyfish (washed and salt removed) to cook soup three times a day. It can not only lower blood pressure, but also reduce phlegm and relieve cough.
Pineapple basket: Eating pineapple regularly can strengthen the hydrolysis of fibrin in the body, which has a good effect on improving blood circulation and eliminating edema and inflammation in hypertension, edema and thrombosis.
Mume: Rich in citric acid, malic acid and succinic acid. For those with hypertension, dizziness, insomnia, and difficulty sleeping at night, 3 pieces of dark plum and appropriate amount of rock sugar can be stewed in boiling water, which has the functions of lowering blood pressure, sleeping peacefully, clearing away heat and promoting fluid production.
Apple: contains malic acid, citric acid, vitamins A, B, C and other nutrients 10. Eating apples often can improve arteriosclerosis.
Five secrets of drinking milk scientifically
Drinking milk is good for health, but many people still have some conceptual misunderstandings about drinking milk. This article introduces some common sense of drinking milk scientifically.
1. It is not advisable to drink milk on an empty stomach in the morning. Because the gastrointestinal peristalsis is fast when the human body is on an empty stomach, the nutrients in milk often rush into the large intestine before being absorbed. In addition, the method of swallowing milk is not feasible, because it will reduce the chance of mixing with saliva in the mouth, which is not conducive to digestion and absorption. You'd better eat some biscuits, cakes, etc. Before drinking milk, or eating snacks while drinking milk.
Drinking milk at night is more beneficial. Scientific research has found that there is a special law of calcium metabolism in human body: at night, especially at midnight, the plasma calcium content will appear a "trough", forcing the body to transport part of calcium in bones to supplement it through regulation mechanism. Although this temporarily maintains the calcium in the blood, the calcium in the bones is reduced. Milk is rich in calcium. Drinking a glass of milk before going to bed can compensate the body's demand for calcium at night.
Milk should not be cooked with sugar. Milk is rich in amino acids. At high temperature, lysine in milk reacts with sugar to produce a new compound-fructosyl amino acid. This substance can't be digested and absorbed by human body, but it affects human health. It is best to drink fresh milk. If it is too cold, you can heat it a little.
If you don't like milk, you can drink yogurt. Most people who hate milk suffer from lactose intolerance. These people can try to drink yogurt. The lactose content in yogurt is greatly reduced, but almost all the nutrients in milk are retained. Among them, lactic acid bacteria can survive and reproduce in human body, which is beneficial to the absorption and utilization of nutrients and improves immunity. Yogurt contains no antibiotics, is easy to digest and absorb, and can be drunk on an empty stomach.
5. Yogurt can't be heated for drinking. Drinking yogurt is mainly about eating its nutrients and living bacteria. For example, when yogurt is heated, the human body can only drink nutrients but lose bioactive lactic acid bacteria, so don't drink it after heating.
Mercury is the smallest earth-like planet in the solar system. It is difficult to observe because it is blocked by the strong light of the sun. On his deathbed, Copernicus regretted that he had never seen Mercury in his life. Since the 1970s, people have learned more about water quantity.
Mercury is the smallest earth-like planet in the solar system. It is difficult to observe because it is blocked by the strong light of the sun. On his deathbed, Copernicus regretted that he had never seen Mercury in his life. Since the 1970s, people have learned more about water quantity.
Mercury is the closest to the sun, only 57.9 million kilometers, which is 0.387 times the distance between the sun and the earth. Mercury's equatorial radius is about 2/5 of that of the earth. Mercury has no air. Mercury looks very similar to the moon, and its surface is covered with craters of all sizes. Volcanic activity may have occurred hundreds of millions of years ago. Now there are several plains that look like volcanic lava on the surface of the star, and there are craters everywhere, large and small. Mercury has a huge concentric structure with a radius of about 1300 km. It is located at 30 degrees north latitude and 0/95 degrees west longitude of Mercury. Because it is extremely hot, it was named "Calorie Basin" by scientists. There are more than 100 craters with radial stripes on the surface of Mercury, and a large number of cliffs three or four kilometers high, some of which are hundreds of kilometers long.
The density of mercury is close to that of the earth. Its center may be a core of iron and nickel similar to the size of the moon, and it also has a magnetic field, but its intensity is only1100 of that of the earth. Mercury's orbital speed is 48km/s, which is faster than the Earth's 18km. It only takes 88 Earth Days, and less than three months after the Earth, Mercury will be 1 year. However, Mercury's "day" is very long. Mercury rotates 1 nearly 58.65 earth days, which means that 1 day of mercury is nearly two months of the earth, and only two sunrises and sunsets can be seen in 1 year on mercury. Mercury, like Venus, has no satellites.
Scientific and technological figures
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Hua is one of the main mathematicians in number theory. But he would rather start a new stove and leave number theory to study algebra and complex analysis that he is not familiar with.
As early as 1940s, he proposed that "genius lies in accumulation, and cleverness lies in diligence". Although Hua is brilliant, he never mentions his own talent. Instead, he regards "diligence" and "accumulation", which are much more important than cleverness, as the key to success, and repeatedly educates young people to learn mathematics so that they can exercise themselves all the time.
In the mid-1950s, Hua proposed: "There should be speed and acceleration." The so-called "speed" means producing results, and the so-called "acceleration" means constantly improving the quality of results. 1978, he earnestly put forward at the Chengdu conference in chinese mathematical society: "Early publication, late evaluation."
Later, it was further put forward: "Efforts are in me, and evaluation is in people." This actually puts forward the objective law of scientific development and scientific work evaluation, that is, scientific work can gradually determine its true value after historical test, which is an objective law that is independent of human subjective will. "
In the 1950s, in the preface to Introduction to Number Theory, Hua compared mathematics to playing chess, and called on everyone to find a master, that is, to compete with great mathematicians. There is a rule in China chess, that is, "Don't tell a true gentleman when watching chess, and have no regrets." .
198 1 year, in a speech in Huainan coal mine, Hua pointed out: "Watching chess is not a gentleman, help each other; I regret the gentleman and change my shortcomings. "
1979 when he was in England, he pointed out: "The village is old and easy to empty, and people are old and easy to disperse. The scientific approach is to abstain from empty and scattered. I am willing to stick to it all my life. "
Einstein is an epoch-making great scientist, the pioneer and founder of modern physics.
1March 879 14 was born in Ulm, Germany, and spent his youth in Switzerland. 1900 graduated from Zurich University of Technology. Unemployment after graduation. After two years of hard work, I found a permanent job in the patent office in Bern. His early series of historic contributions were all completed here.
1909 began to teach in universities. 19 14 was invited to return to Germany as the director of the Royal William Institute of Physics and a professor at the University of Berlin. 1933 when Hitler came to power, Einstein was persecuted for the first time because he was a Jew and resolutely defended democracy, and was forced to move to Princeton, USA. 1940 American citizenship. 1955 April 18 died in Princeton.
One of Einstein's pioneering contributions is the development of quantum theory, and his iconic career is his theory of relativity. In his paper entitled "On Electrodynamics of Moving Objects" published in 1905, he put forward the special theory of relativity completely. After the establishment of special relativity, Einstein began to devote himself to the study of gravity theory. Einstein's cosmology has a great influence on astronomy. 19 17, Einstein published his first paper on the universe, Cosmological Investigation Based on General Relativity, which announced the birth of relativity.
He once said: "Scientific research can dispel superstition because it encourages people to think and observe things according to causality." His study of cosmology embodies this spirit of opposing superstition.
The national 863 project "Research on Key Technologies of Rotary Steering Drilling System" undertaken by Shengli Oilfield Drilling Institute, after nearly three years of tackling key problems, was successfully tested in Shengli Oilfield at the end of September, marking a breakthrough in this research.
Rotary steering drilling technology is a new automatic drilling technology developed at the end of last century, which is an effective technology to reduce the cost of oil and gas development and improve oil and gas recovery. Known as the highest level of drilling technology at present. The international research and development of rotary steering drilling technology began in the early 1990s, and more than 20 companies have participated in the research and development of this technology. So far, only three of the world's largest technical service companies have formed field application capabilities.
In order to meet the needs of oil and gas development, improve the domestic drilling technology level and participate in the worldwide drilling market competition, Shengli Drilling Institute started the preliminary research of rotary steering drilling technology on 1998, and entered the key technology research and prototype development stage of rotary steering drilling system in 2002. The rotary steering project team of Drilling Institute and Xi 'an Anyou University established a joint development project team, which realized the complementary technical advantages. The Drilling Institute and Xi Anyou University jointly carried out hundreds of design changes and dozens of indoor simulation tests of key units, developed three sets of rotary steering drilling downhole tool system prototypes, and carried out more than 20 ground tests in four rounds. On August 22-23, 2006, the joint field test of the whole rotary steering drilling system, including rotary steering drilling downhole tool system, MWD measurement while drilling system, information uploading system and ground monitoring system, was carried out in Ying 12- Xie 225 well, with the purpose of testing the function of keeping the original orientation in the deviated well to realize deflection, testing the control and storage during deflection, and testing the comprehensive performance of the mechanical structure.
It is understood that the drilling institute of Shengli Oilfield will improve its technology in the next step to lay the foundation for the commercial application of rotary steering drilling system.
On February 24th, 2005, 65438, the "863" major project of electric vehicles —— "Research on the Network, Bus and Communication Protocol of Electric Vehicles" undertaken by Institute of Electrotechnics of Chinese Academy of Sciences passed the acceptance organized by the Energy Technology Office of the 863 Program of the Ministry of Science and Technology in Beijing.
The main goal of the project "Research on the Network, Bus and Communication Protocol of Electric Vehicles" is to study the technical characteristics of the network bus of electric vehicles, provide bus and related technical support for the internal units of electric vehicles, promote the standardization and standardization of the communication protocol of electric vehicles, and lay the foundation for the industrialization of electric vehicles in China.
Through the unremitting efforts of the researchers, the task was successfully completed. A relatively complete database system of electric vehicle communication protocol is established, and a special internal recommendation draft of electric vehicle CAN bus communication protocol is formulated, which can be applied to various types of electric vehicles such as pure electric vehicles, hybrid electric vehicles and fuel cells, and is an important step towards the standardization of electric vehicle communication protocol. The test specification of electric vehicle bus is revised to make it more suitable for the practical application of electric vehicle bus system. A common platform of high-speed bus of power system, low-speed CAN bus of body network and LIN bus is established, which can develop various buses and communication protocols for electric vehicles. Through the research of electromagnetic compatibility, the electromagnetic compatibility test platform of electric vehicle bus system is initially established. At the same time, the automotive electronics group also conducted in-depth research on other advanced automotive bus technologies such as TTCAN and LIN, and conducted theoretical discussion on FLEXRAY bus, which provided sufficient technical reserves for the subsequent development of bus technology.
At the acceptance meeting, the expert group spoke highly of the work of the Institute of Electrical Engineering, unanimously agreed that the project passed the acceptance, and suggested further strengthening cooperation with the whole vehicle unit, perfecting the content of the agreement and making it a national standard; Improve the public test platform of electric vehicle communication network, deeply study key technologies, and promote the development of vehicle bus technology in China.
A few days ago, the project "Research and Application of Key Technologies of Parallel Machining Center for Complex Curved Surfaces and Blades" undertaken by Harbin Measuring Tool Group Co., Ltd. passed the acceptance of the robot technology theme organization.
The project "Research and Application of Key Technologies of Parallel Machining Center for Machining Complex Curved Surfaces and Blades" has deeply studied the key technologies such as the structure of parallel machine tool, the development of digital servo system, the application of CAD/CAM, the machining of complex curved surfaces, the machining error and precision analysis of parallel structure, the calibration of mechanism structural parameters, and the improvement of machine tool stiffness. It has overcome the overall layout of machine tool, the numerical control system of seven-axis parallel machine tool and the precision guarantee of parallel machining center, and made some progress in the structural parameter detection and machine tool calibration of parallel machine tool.
According to the requirements of the contract, the research group developed a 1 commercial prototype suitable for the parallel machining center for machining complex curved blades. Not only the main technical indicators have reached the requirements specified in the task book, but also four kinds of products have been put into practical production in Harbin Steam Turbine Factory, which are used to process small and medium-sized moving blades and guide vanes. The machining accuracy and efficiency are equivalent to those of imported machine tools, which better meet the production and technological requirements of users.
Engelberg, an American robot elder, was born in Brooklyn, USA in July, 1925. Graduated from Columbia University. After World War II, I worked in a company. 1956, he started working closely with Devall to design an industrial robot. They raised enough funds to start manufacturing in 1959, and finally manufactured the world's first industrial robot, named "Unimet", which means "general automation".
Engelberg and De Waal organized "Unimet" company, which is the first factory in the world specializing in the production of robots.
In order to promote robots, engelberg went to Japan on 1967 to publicize and introduce robots. More than 600 people in Japan listened to his speech. Since then, engelberg has been known as "the patriarch of American robots".