Development of high magnetic field superconducting magnet technology and applications in China
机械专业外文文献翻译
翻译部分英文原文High-speed machining and demand for the development ofHigh-speed machining is contemporary advanced manufacturing technology an important component of the high-efficiency, High-precision and high surface quality, and other features. This article presents the technical definition of the current state of development of China's application fields and the demand situation.High-speed machining is oriented to the 21st century a new high-tech, high-efficiency, High-precision and high surface quality as a basic feature, in the automobile industry, aerospace, Die Manufacturing and instrumentation industries gained increasingly widespread application, and has made significant technical and economic benefits. contemporary advanced manufacturing technology an important component part.HSC is to achieve high efficiency of the core technology manufacturers, intensive processes and equipment packaged so that it has a high production efficiency. It can be said that the high-speed machining is an increase in the quantity of equipment significantly improve processing efficiency essential to the technology. High-speed machining is the major advantages : improve production efficiency, improve accuracy and reduce the processing of cutting resistance.The high-speed machining of meaning, at present there is no uniform understanding, there are generally several points as follows : high cutting speed. usually faster than that of their normal cutting 5 -10 times; machine tool spindle speed high, generally spindle speed in -20000r/min above 10,000 for high-speed cutting; Feed at high velocity, usually 15 -50m/min up to 90m/min; For different cutting materials and the wiring used the tool material, high-speed cutting the meaning is not necessarily the same; Cutting process, bladed through frequency (Tooth Passing Frequency) closer to the "machine-tool - Workpiece "system the dominant natural frequency (Dominant Natural Frequency), can be considered to be high-speed cutting. Visibility high-speed machining is a comprehensive concept.1992. Germany, the Darmstadt University of Technology, Professor H. Schulz in the 52th on the increase of high-speed cutting for the concept and the scope, as shown in Figure 1. Think different cutting targets, shown in the figure of the transition area (Transition), to be what is commonly called the high-speed cutting, This is also the time of metal cutting process related to the technical staff are looking forward to, or is expected to achieve the cutting speed.High-speed machining of machine tools, knives and cutting process, and other aspects specific requirements. Several were from the following aspects : high-speed machining technology development status and trends.At this stage, in order to achieve high-speed machining, general wiring with high flexibility of high-speed CNC machine tools, machining centers, By using a dedicated high-speed milling, drilling. These equipment in common is : We must also have high-speed and high-speed spindle system feeding system, Cutting can be achieved in high-speed process. High-speed cutting with the traditional cutting the biggest difference is that "Machine-tool-workpiece" the dynamic characteristics of cutting performance is stronger influence. In the system, the machine spindle stiffness, grip or form, a long knife set, spindle Broach, torque tool set, Performance high-speed impact are important factors.In the high-speed cutting, material removal rate (Metal Removal Rate, MRR), unit time that the material was removed volume, usually based on the "machine-tool-workpiece" whether Processing System "chatter." Therefore, in order to satisfy the high-speed machining needs, we must first improve the static and dynamic stiffness of machine spindle is particularly the stiffness characteristics. HSC reason at this stage to be successful, a very crucial factor is the dynamic characteristics of the master and processing capability.In order to better describe the machine spindle stiffness characteristics of the project presented new dimensionless parameter - DN value, used for the evaluation of the machine tool spindle structure on the high-speed machining of adaptability. DN value of the so-called "axis diameter per minute speed with the product." The newly developed spindle machining center DN values have been great over one million. To reduce the weight bearing, but also with an array of steel products than to the much more light ceramic ball bearings; Bearing Lubrication most impressive manner mixed with oil lubrication methods. In the field of high-speed machining. have air bearings and the development of magnetic bearings and magnetic bearings and air bearings combined constitute the magnetic gas / air mixing spindle.Feed the machine sector, high-speed machining used in the feed drive is usually larger lead, multiple high-speed ball screw and ball array of small-diameter silicon nitride (Si3N4) ceramic ball, to reduce its centrifugal and gyroscopic torque; By using hollow-cooling technology to reduce operating at high speed ball screw as temperature generated by the friction between the lead screw and thermal deformation.In recent years, the use of linear motor-driven high-speed system of up to'' Such feed system has removed the motor from workstations to Slide in the middle of all mechanical transmission links, Implementation of Machine Tool Feed System of zero transmission. Because no linear motor rotating components, from the role of centrifugal force, can greatly increase the feed rate. Linear Motor Another major advantage of the trip is unrestricted. The linear motor is a very time for a continuous machine shop in possession of the bed. Resurfacing of the very meeting where avery early stage movement can go, but the whole system of up to the stiffness without any influence. By using high-speed screw, or linear motor can greatly enhance machine system of up to the rapid response. The maximum acceleration linear motors up to 2-10G (G for the acceleration of gravity), the largest feed rate of up to 60 -200m/min or higher.2002 world-renowned Shanghai Pudong maglev train project of maglev track steel processing, Using the Shenyang Machine Tool Group Holdings Limited McNair friendship company production plants into extra-long high-speed system for large-scale processing centers achieve . The machine feeding system for the linear guide and rack gear drive, the largest table feed rate of 60 m / min, Quick trip of 100 m / min, 2 g acceleration, maximum speed spindle 20000 r / min, the main motor power 80 kW. X-axis distance of up to 30 m, 25 m cutting long maglev track steel error is less than 0.15 mm. Maglev trains for the smooth completion of the project provided a strong guarantee for technologyIn addition, the campaign machine performance will also directly affect the processing efficiency and accuracy of processing. Mold and the free surface of high-speed machining, the main wiring with small cut deep into methods for processing. Machine requirements in the feed rate conditions, should have high-precision positioning functions andhigh-precision interpolation function, especially high-precision arc interpolation. Arc processing is to adopt legislation or thread milling cutter mold or machining parts, the essential processing methods. Cutting Tools Tool Material developmenthigh-speed cutting and technological development of the history, tool material is continuous progress of history. The representation ofhigh-speed cutting tool material is cubic boron nitride (CBN). Face Milling Cutter use of CBN, its cutting speed can be as high as 5000 m / min, mainly for the gray cast iron machining. Polycrystalline diamond (PCD) has been described as a tool of the 21st century tool, It is particularly applicable to the cutting aluminum alloy containing silica material, which is light weight metal materials, high strength, widely used in the automobile, motorcycle engine, electronic devices shell, the base, and so on. At present, the use of polycrystalline diamond cutter Face Milling alloy, 5000m/min the cutting speed has reached a practical level. In addition ceramic tool also applies to gray iron of high-speed machining; Tool Coating : CBN and diamond cutter, despite good high-speed performance, but the cost is relatively high. Using the coating technology to make cutting tool is the low price, with excellent mechanical properties, which can effectively reduce the cost. Now high-speed processing of milling cutter, with most of the wiring between the Ti-A1-N composite technology for the way of multi-processing, If present in the non-ferrous metal or alloy material dry cutting, DLC (Diamond Like Carbon) coating on thecutter was of great concern. It is expected that the market outlook is very significant;Tool clamping system : Tool clamping system to support high-speed cutting is an important technology, Currently the most widely used is a two-faced tool clamping system. Has been formally invested as a commodity market at the same clamping tool system are : HSK, KM, Bigplus. NC5, AHO systems. In the high-speed machining, tool and fixture rotary performance of the balance not only affects the precision machining and tool life. it will also affect the life of machine tools. So, the choice of tool system, it should be a balanced selection of good products.Process ParametersCutting speed of high-speed processing of conventional shear velocity of about 10 times. For every tooth cutter feed rate remained basically unchanged, to guarantee parts machining precision, surface quality and durability of the tool, Feed volume will also be a corresponding increase about 10 times, reaching 60 m / min, Some even as high as 120 m / min. Therefore, high-speed machining is usually preclude the use of high-speed, feed and depth of cut small cutting parameters. Due to the high-speed machining cutting cushion tend to be small, the formation of very thin chip light, Cutting put the heat away quickly; If the wiring using a new thermal stability better tool materials and coatings, Using the dry cutting process for high-speed machining is the ideal technology program. High-speed machining field of applicationFlexible efficient production lineTo adapt to the needs of new models, auto body panel molds andresin-prevention block the forming die. must shorten the production cycle and reduce the cost of production and, therefore, we must make great efforts to promote the production of high-speed die in the process. SAIC affiliated with the company that : Compared to the past, finishing, further precision; the same time, the surface roughness must be met, the bending of precision, this should be subject to appropriate intensive manual processing. Due to the extremely high cutting speed, and the last finishing processes, the processing cycle should be greatly reduced. To play for machining centers and boring and milling machining center category represented by the high-speed machining technology and automatic tool change function of distinctions Potential to improve processing efficiency, the processing of complex parts used to be concentrated as much as possible the wiring process, that is a fixture in achieving multiple processes centralized processing and dilute the traditional cars, milling, boring, Thread processing different cutting the limits of technology, equipment and give full play to the high-speed cutting tool function, NC is currently raising machine efficiency and speed up product development in an effective way. Therefore, the proposed multi-purpose tool of the new requirements call for a tool to complete different partsof the machining processes, ATC reduce the number of ATC to save time, to reduce the quantity and tool inventory, and management to reduce production costs. More commonly used in a multifunctional Tool, milling, boring and milling, drilling milling, drilling-milling thread-range tool. At the same time, mass production line, against the use of technology requires the development of special tools, tool or a smart composite tool, improve processing efficiency and accuracy and reduced investment. In the high-speed cutting conditions, and some special tools can be part of the processing time to the original 1 / 10 below, results are quite remarkable. HSC has a lot of advantages such as : a large number of materials required resection of the workpiece with ultrafine, thin structure of the workpiece, Traditionally, the need to spend very long hours for processing mobile workpiece and the design of rapid change, short product life cycle of the workpiece, able to demonstrate high-speed cutting brought advantages.中文译文高速切削加工的发展及需求高速切削加工是当代先进制造技术的重要组成部分，拥有高效率、高精度及高表面质量等特征。
铁芯在新能源电机中的应用
铁芯在新能源电机中的应用Iron cores play a critical role in the development and operation of new energy motors. 铁芯在新能源电机中发挥着至关重要的作用。
As the central component of the motor, the iron core is responsible for creating a magnetic field that drives the rotation of the motor. 作为电机的核心组件，铁芯负责产生磁场，驱动电机的旋转。
Its high magnetic permeability and low core loss make it an ideal material for use in electric motors. 其高磁导率和低核心损耗使之成为电动机中的理想材料。
One of the key advantages of iron cores in new energy motors is their ability to efficiently convert electrical energy into mechanical energy. 铁芯在新能源电机中的一个关键优势是其能够高效地将电能转化为机械能。
This efficiency is crucial for maximizing the performance and longevity of electric vehicles and other green technologies. 这种效率对于最大化电动车辆和其他绿色技术的性能和寿命至关重要。
By reducing energy loss and improving power output, iron cores help enhance the overall efficiency and effectiveness of new energy motors. 通过减少能量损失和提高功率输出，铁芯有助于提高新能源电机的整体效率和性能。
隧穿磁阻效应磁传感器 绝缘强度技术参数
隧穿磁阻效应磁传感器绝缘强度技术参数1.隧穿磁阻效应磁传感器的工作原理是利用磁阻效应来检测磁场的变化。
The working principle of tunneling magnetoresistance magnetic sensor is to detect the change of magnetic field using the tunneling magnetoresistance effect.2.这种磁传感器具有灵敏度高、响应速度快等优点。
This type of magnetic sensor has the advantages of high sensitivity and fast response speed.3.绝缘强度是指磁传感器内部的绝缘材料能够承受的最高电压。
Insulation strength refers to the maximum voltage that the insulation material inside the magnetic sensor can withstand.4.绝缘强度是磁传感器的重要技术参数之一，直接关系到产品的安全性和可靠性。
Insulation strength is one of the important technical parameters of magnetic sensor, which is directly related to the safety and reliability of the product.5.通常情况下，磁传感器的绝缘强度应该能够承受额定工作电压的1.5倍以上。
Generally, the insulation strength of the magnetic sensor should be able to withstand at least 1.5 times the rated operating voltage.6.除了绝缘强度外，磁传感器的环境温度范围也是一个重要的技术参数。
南理工_new energy technology_Research and development of controlled nuclear fusion
1INTRODUCTIONEnergy and life are closely related. We have to admit that we are facing an unprecedented energy crisis. It is an urgent task that we develop and use new energy. At present, nuclear energy is an important leading role in the development of new energy. Nuclear energy comes from fission and fusion. Fission has been widely used in the field of power generation. The nuclear power station has more than 400. As the nuclear fusion reaction requires a very high temperature, so the realization of nuclear fusion is very complicated and very difficult. But there are two major advantages of nuclear fusion: One is that nuclear fusion does not produce long-term and high levels of nuclear radiation, the other one is the nuclear fusion materials more than nuclear fission materials on the earth. According to the current world energy consumption, it can let the human use for 10 billions years that the earth has the nuclear fusion energy.Now, we are faced with how to control the process of nuclear fusion and how to use the heat to generate electricity. Once these complex technical problems are solved, the entire world's energy problem will be solved thoroughly. The developed countries continue to invest a lot of manpower, material resources and financial resources to study and develop it because of the long-term significance of nuclear fusion.2 DEVELOPMENT BACKGROUND OF CONTROLLED NUCLEAR FUSIONNuclear fusion released a great energy and people did not stop it from the beginning of the 50's in twentieth Century. The ultimate goal of nuclear fusion is not to make a hydrogen bomb. The long-term goal is the peaceful use of nuclear fusion. 2.1Nuclear fusion reactionThe nuclear fusion fuel is light atoms, such as hydrogen isotope deuterium and tritium. Under certain conditions (such as high temperature and high pressure), the nuclear of atoms interact with each other and form a new reaction of heavy nuclei. There is loss of mass. So there is a release ofenergy in the reaction. As shown in figure 1.Fig 1. nuclear fusion reaction. It describes the fusion reaction The equation reaction is as follows when deuterium and tritium has fusion reaction:MeVnHeTD6.17142++→+The mass of the reactants is more than the mass of the product from this reaction equation. And the reaction takes place with a mass loss, which is converted to 17.6MeV energy in the middle of the process. The content of deuterium is very rich on the earth. 1L of water contains 0.03 grams of deuterium. Our earth has 1.3 billion and 86 million cubic kilometers of water. It contains J311047.11⨯energy. These energies are enough for us to use ten billion years.2.2Controlled nuclear fusionThe explosion of a hydrogen bomb is primarily nuclear fusion. But it is the high temperature and high pressure environment produced by the atomic bomb explosive. Then the deuterium and tritium had a nuclear fusion reaction, and released a great energy. But the explosive energy of this moment is not controlled. If we can control the energyResearch and development of controlled nuclear fusionE-mail:Abstract: This paper tells the development of controlled nuclear fusion energy at the first. Then it analyzes the definition and the main research methods and the problems of controlled nuclear fusion. Magnetic confinement fusion and inertial confinement fusion are two main research approaches in the study of controlled nuclear fusion. This paper explains the principle of magnetic confinement fusion firstly. Then it analysis the working principle of tokamak. It also analyzes the development of magnetic confinement nuclear fusion in China. In the inertial confinement fusion, the paper firstly explains the basic principle of the method. Then this paper introduces the development of the NIF device in American and SG engineering in nuclear fusion research in China. People still insist on the study of nuclear fusion, people will be able to achieve controlled nuclear fusion in the future.Key Words: Controlled nuclear fusion; Magnetic confinement fusion; Inertial confinement fusionreleased by the fusion, and use it to social production and human life. Then we achieve controlled nuclear fusion. In “Spider Man 2”, the energy used by Dr. octopus, is controlled nuclear fusion.2.3 Research way of controlled nuclear fusionFrom the last century 50's to now, people poured a lot of energy to study nuclear fusion. We still believe that there is still a long way to go before we achieve controlled nuclear fusion. Scientists estimate that we have to wait for more than 30 years before building nuclear fusion power station. In this study, people put forward various ideas and the construction of the device is also various. But from the current point of view, the way to controlling nuclear fusion is divided into two major categories: magnetic confinement fusion (MCF) and inertial confinement fusion (ICF). This paper will introduce and analyze them in the third and fourth sections. However, both MCF and ICF, they are just the experimental device. It is quite a long distance away from the real economy. And there are also a variety of technical problems to solve.2.4 The problem of controlled nuclear fusionDeuterons and tritons are positively charged under normal conditions. And they are mutually exclusive. So if we want to put them aggregate. We need to use a lot of energy to enable them to overcome the repulsion. The deuteron and Triton have a large enough kinetic energy when the nuclear fusion material is heated to a high temperature (one hundred million degrees ). But it only provides the speed of the collision, we should also restrict the nuclear material, so that they reach a high enough density. This would make it possible for the fusion of deuterium and tritium. This is the realization method of deuteron and triton polymerization. From the above conditions for the occurrence of fusion, it can be found that controlled nuclear fusion is very difficult. This paper will discuss the problem of controlled nuclear fusion:1) Constraint problem of plasma. Fusion nuclear material format plasma after high temperature and high pressure treatment. Due to the plasma is a highly complex multibody system, which has the electromagnetic interaction, various wave particle interactions and nonlinear turbulent flow problems. Figure 2 shows the complexity of the internal structure of the plasma. If we want to master the laws of these plasmas, we must need a lot of manpower, materialresources and financial resources.Fig 2. Four states of matter2) Ignition problem and material problem. It requires 100 millions degrees of high temperature environment to start the fusion reaction. After the occurrence of nuclear fusion, its own energy can be maintained by the control. First ,it is a very difficult technical problem how to produce 100 millions degrees of high temperature. Another is the material problem, what material can withstand thetemperature of 100 millions degrees. A strong magnetic field is required in the confinement of the plasma. The strong magnetic field is produced by high current, which requires the conductor to be superconducting material, and it has not solved the problem of high temperature superconducting materials. Fig 3 lists the high temperature superconductor materials. The highest critical temperature of high temperature superconductor material is 165K. It isstill very low.FIG 3.Development of high temperature superconducting materials. It shows the critical temperature of high temperature superconductor material.3) Neutron radiation problem. A large number of neutrons will be produced when deuterium and tritium occur fusion. The radiation problem is produced when the material is irradiated by neutron. And these neutrons will damage the reactor material. This is a problem that must be considered. There are 3 major challenges controlled nuclear fusion, the technology problem of controlled nuclear fusion is still more than these.3 MCFMagnetic confinement fusion process is generally as follows:First, deuterium and tritium and their free electron format aplasma in the ultra-high temperature. Then, we use the magnetic field of the special shape to constrain and compress the plasma, so that they can achieve the ignition condition of controlled nuclear fusion. Ignition condition is: 1) Reactor temperature is higher than 100 millions degrees. 2) The density of the plasma is greater than 1020 per cubic metre.3) The time of the constraint should be more than 1s.So far, MCF is a nuclear fusion approach which people spend most research and money on it. Tokamak device is one of the important roles of magnetic confinement nuclear fusion. 3.1 TokamakTokamark was invented in the 50's of last century. It is a circular container for controlled nuclear fusion by magnetic confinement. Its name is made up of the first 2 letters of 4 words. They are toroidal ,kamera, magnet and kotushka. It is feasible that uses Tokamak to start nuclear fusion .But its related results are generated in the form of a broken pulse, which is still a big gap in the real life. Now, the superconducting technology has been used in the Tokar Mark coil. This is a major breakthrough of controllednuclear fusion. At present, the study of the Tokamak has become a hot international craze.3.2 Working principle of TokamakFig. 4 Schematic diagram of Tokamak device ，it shows the principle ofTokamak.Fig. 5 Physical structure of Tokamak ，it shows the vacuum chamber of the Tokamak.From Fig4 and fig 5, it can be seen that the main body of the Tokamak device is composed of 2 parts, namely, the magnetic field system and the vacuum system.Magnetic field system has 2 main functions. The main effect of the longitudinal field coil is used to produce a strong longitudinal magnetic field. And then the plasma is confined in a vacuum tube. So they maybe start to react. The first step is to make the material become the plasma state. Plasma state is the fourth state of matter. The material is a fully ionized in this state. Its whole is electrically neutral. And due to the high temperature, it has enough kinetic energy to get rid of the shackles of the atomic nucleus. At this time, the atomic nucleus is completely exposed, and prepare for the conditions for the collision of the nucleus. When the plasma is heated to tens or hundreds of millions of degrees, nuclei can get rid of repulsion, gather together and form a fusion reaction. If there is enough density and enough heat to restrain them, the reaction will be able to run steadily.Common heating systems are as follows:1) Ohmic heating. The change of the magnetic field generates an electric potential, which generates an electric current in the plasma. The plasma has a resistance, whichcan be heated by ohmic heating. It is such as resistance element.2) Microwave heating. We use electromagnetic waves to heat plasma. The principle is same as the electromagnetic microwave.3) Neutral beam heating. Neutral beam heating is actually an energy transfer process. The energy of the particles is passed to the plasma after injecting the energetic particles into the Tokamak. And the heating is realized. We need to speed up the particles with the accelerator, so the cost is relatively high.Vacuum system. The vacuum chamber is the ring. The wall of the vacuum chamber is made of stainless steel. We must consider the mechanical strength. The wall must have a certain gap, in order to ensure the penetration of magnetic field. Gas pumping system generally is a turbo molecular pump. This device can make the vacuum chamber pressure less than Pa 610 .3.3 Development of magnetic confinement nuclear fusion in ChinaFrom the last century 50's, China began the research of nuclear fusion, mainly concentrated in the Southwest Institute of physics and the Institute of plasma physics in Chinese Academy of sciences. HL-1 was on operation in 1984. China developed a HT-7 superconducting Tokamak, marking China become the world's fourth superconducting Tokamark in 1994. In 2005, China completed the first non circular cross section Tokamak device - EAST. Then, in 2006, China's first EAST achieved the first ignition, whichis an unprecedented achievement.Fig 6.EAST .The graph shows its shapeEAST has a first set of neutral beam injection (NBI) in 2012. This marks the EAST upgrade to EAST-NBI. 3.4 ITERThe International Thermonuclear Experimental Reactor program called ITER. The proposal originated in 1985 .It was designed to work in 1988. The design of the project was completed in 2001, and it has cost $1.5 billion. Our government insists on participating in the ITER program for the sake of our country's energy. In 2003, our country decided to formally participate in ITER negotiations. Now ITER has 7 member countries - China, the EU, South Korea,Russia, Japan, India and the United States. Scientists assessthe construction of ITER will cost $5billions in 1998.Fig. 7 Schematic diagram of ITER.It is actually a nuclear fusion power stationAs shown in Figure 7, the reactor unit in the ITER project is a large Tokamak device. ITER device not only reflects the latest achievements in the field of fusion energy research, but also the world's top technology, such as high current accelerator technology, superconducting technology, complex control technology and so on.4 ICFInertial confinement fusion is proposed in the 60's of the last century. This fusion technique utilizes a laser. So as to achieve the conditions of ignition, we first use a laser to heat the deuterium and tritium fuel to reach the temperature of the reaction, and let it be compressed. Then we will get the energy gain.4.1 Principle of inertial confinement fusionFigure 8 Inertial confinement nuclear fusion. It describes the basic principles of ICFAs shown in Figure 8, the fuel ball is the main component of the inertia constraint. Spherical shell material can be metal or glass, etc. The ball is equipped with deuterium and tritium gas. The principle of inertia is as follows:1) With the laser irradiation, The surface of the shell will absorb energy and evaporation.2) According to Newton's third law, the inner layer of the sphere will be squeezed because of the effect of reaction force. At this time, the pressure increases in the gas, the temperature is also rising.3) With the continuous irradiation of the laser, the fuel isconstantly squeezed into the center. If the radius of the ball is R1 and the compression ratio is R2 .So the compression ratio is R1/R2.4) When R1/R2 can reach about 30. So the temperature can be reached very high. When the temperature reaches the ignition temperature, the mixture of the small ball will explode. The process is very short. There are more than three such explosions per second, and can continue to go on. The energy is equivalent to a million kilowatt class of power stations.4.2 Technical difficulties of inertial confinement nuclear fusionWhy don ’t we still use this technology to build power stations today? This paper will analyze the causes.1) No matter whether the laser beam or the particle beam, , their power has not yet reached the power to build power stations.2) Irradiation problems. Laser irradiation must be uniform. And fuel balls must also be clean. Once the technical problems occur, it will lead to the compression is not uniform, the explosion rate is not high.3) Improvement of explosive method. The method of center explosion is not necessarily the best solution. Whether there are better and more economical plan. Many countries are trying to study and explore the optimal method of ignition.4.3 NIF devices in the United StatesU.S. National Ignition Facility began to construct in 1997. Because of a lot of power and serious over budget, so that it was originally planned for 5 years to complete the project. Thus it was completed in February 2009. Figure 9 for the construction of NIF. From the picture, we can see a lot ofholes for the laser meter.Figure 9: NIFThe whole set of NIF device has 6000 different kinds ofhigh-tech equipment. And the construction of the plant is as long as a kilometer. In Fig 9, the device is designed to allow the 192 laser device to launch a laser at the same time in10-9 seconds and focus on the size of a pencil head. As shown in Figure 10, it is the fuel ball in the NIF device.Allowable error can not be greater than 30ps. In order to achieve such a high precision, manufacturing and installation of 6000 kinds of equipment is very important. All of the equipment is nearly perfect. According to theofficial announcement, NIF has cost $3.5billion.Fig 10.Installation of fuel ballsThe United States NIF successfully realized the ignition. Its output is greater than the input of energy in July 5, 2012. This is a landmark breakthrough in controlled nuclear fusion. But unfortunately, due to various external factors, the study of NIF turned to the study of nuclear weapons. 4.4 SG projectThe device belongs to the Nd: glass laser system. It ranks fourth in the world's laser device. We get the result of a lot of physical experiments in our country from it. SG II provides an irreplaceable means of experiment in inertial confinement fusion, X laser and other high-tech fields. It is an important experimental platform in this field. SG Ⅲ has successfully completed the construction. It can reach the level of "8 beams of light, pulse - 10000J". These achievements mark our country to become the third country to master high power laser driver technology. At the same time, it also makes China become the second country with independent research and construction of a new generation of high power laser driver.The ultimate goal of the SG series device is to realize ignition of controlled thermonuclear fusion by our country independently.Fig 11. SG experimental device It is the independent research and development of China. 5 SUMMARYWe consume fossil energy within 100 years. People are looking for new energy. One of them is nuclear power. Today, people has realized the commercialization of nuclear fission. But the fission of the raw material is very limited, the fuel of nuclear fusion is inexhaustible. In order to achieve the dream of fusion energy, people have paid great efforts.Although the realization of controlled nuclear fusion is so difficult, people has overcame considerable difficulties by REFERENCES[1]K. M. Feng. Liberal controlled nuclear fusion and theInternational Thermonuclear Experimental Reactor (ITER) program [J]. Chinese nuclear power, 2009, 2 (3): 212-219.[2] B. L. Tan, C. H. Pan. Rethinking on the research approachesof controlled nuclear fusion [J]. Journal of nature, 2002, 24(6): 348-351.[3]G. C. Wang, Z. H. Yuan. ICF [J]. Chinese science, 1995, 6: 0[4]H. Liu. ICF[J]. modern physics knowledge, 2002, 14 (01):13-15.[5]J. M. Zhang. The force and structure analysis of the ring tothe field coil in a typical Tokamak device [D]. Electronic Technology University, 2009[6]Y. Qi. Controlled nuclear fusion: the ultimate energy [J].world science, 2010 (10): 20-22.[7]X. T. Xian. Inertial confinement fusion research progress andProspect [J]. nuclear science and engineering, 2000, 20 (3): 248-251.[8]S. Y. Zhu. important frontier of modern physics, [J]. modernphysics, 1991, 3 (03): 3-2.[9]H. Y. Jiang,D. L. Cu. fusion energy and controlled nuclearfusion research of [J]. modern physics, 2004, 16 (05): 17-18.[10]Q. Sun. SG-III laser device reliability research [D]. nationaldefense science and Technology University, 2005。
电子信息工程论文(英文)
Electronic and information engineering is the application of the computer and modem technology for electronic information control and information processing the discipline， the main research information acquisition and processing，electronic equipment and information system design， development， application and integration. Now， electronic and information engineering has covered many aspects of the society，like telephone exchange station how to deal with various phone signal， a mobile phone is how to transfer our voice even image， the network around us how to transfer data， and even of the army of the information age how to confidential information transmission， are involved in electronic and information engineering application technology. We can through some basic knowledge learning know these things， and able to apply more advanced technology in new product research and electronic and information engineering is professional This program is to cultivate master the modern electronic technology theory， familiar with electronic system design principle and design method， have stronger computer, foreign language and corresponding engineering technology application ability， facing the electronictechnology， automatic control and intelligent control，computer and network technology， electronic, information, communication field of broad caliber, the high quality，comprehensive development of integrated with innovation ability engineering technology talent development.Electronic information engineering major is learning the basic circuit of knowledge, and master the computer processing with the method of information。
JJF1023电学计量名词术语(修改稿9)
6.1.1 真空磁导率(permeability of vacuum) 6.1.2 介电系数，电容率(permittivity)0也称电常数(electric constant)。
6.1.3电动势(electromotive force)6.1.4接触电动势(contact electromotive force) 6.1.5感应电(动)势(induced electromotive force)6.1.6导体(conductor)6.1.7绝缘体(insulator)6.1.8半导体(semiconductor)6.1.9超导体(superconductor)6.1.10接触电位(差)（contact potential[difference]）6.1.11热电效应(thermoelectric effect)6.1.12塞贝克效应(Seebeek effect)6.1.13珀耳帖效应(Polfier effect)6.1.14汤姆逊效应(Thomson effect)6.1.15约瑟夫森效应(Josephson effect)6.1.16量子化霍尔效应(quantum Hall effect) 6.1.17单电子隧道效应(single electron tunnel effect)6.1.18 功率天平（Watt balance）6.1.19交流电阻时间常数(time constant of ac resistor)6.1.20介电强度(dielectric strength)6.1.21绝缘电阻(insulation resistance)6.1.22 电流(electric current)6.1.23 电压(voltage)6.1.24 电阻(resistance)6.1.25 电导(conductance)6.1.26 阻抗(impedance)6.1.27 导纳(admittance)6.1.28 电容(capacitance)6.1.29 电感(inductance)6.1.30 电阻率(resistivity)6.1.31 电导率(conductivity)6.1.32 磁导率（permeability）6.1.33 静电场(electrostatic field)6.1.34 电场强度(electric field intensity)6.1.35 电位(electric potential)6.1.36 电荷(electric charge)6.1.37 库伦定律(Coulomb’s law)6.1.38 电位移(electric displacement)6.1.39 拉普拉斯方程(Laplace’s equation) 6.1.40 静电感应(electrostatic induction)6.1.41 恒定电场(steady electric field)6.1.42 欧姆定律(Ohm law)6.1.43 焦耳定律(Joule’s law)6.1.44 安培(ampere)6.1.45 伏特(volt)6.1.46 库仑(couomb)6.1.47 欧姆(ohm)6.1.48 西门子(siemens)6.1.49 法拉(farad)6.1.50 亨利(henry)6.1.51 瓦特(watt)6.1.52 电路(electric circuit)6.1.53 激励(excitation)6.1.54 响应(response)6.1.55 电路元件(electric circuit elements) 6.1.56 无源二端元件(passive two-terminal elements)6.1.57 电压源(voltage sources)6.1.58 电流源(current sources)6.1.59 受控源(controlled sources)6.1.60 开路(open circuit)6.1.61 短路(short circuit)6.1.62 理想变压器(ideal transformer)6.1.63 基尔霍夫定律(Kirchhoff’s law)6.1.64 直流(direct current)6.1.65 交流(alternating current)6.1.66 正弦电流(sinusoidal current)6.1.67 频率(frequency)6.1.68 赫兹(hertz)6.1.69 相位(phase)6.1.70 相量(phasor)6.1.71相量图(phasor diagram)6.1.72 谐振(resonance)6.1.73 铁磁谐振电路(ferro- resonance circuit)6.1.74 三相电路(three-phase circuit)6.1.75 三相电源(three-phase sources)6.1.76 三相负载(three-phase loads)6.1.77 相电压(phase voltages)6.1.78 线电压(line voltages)6.1.79 相电流(phase currents)6.1.80 线电流(line currents)6.1.81 对称三相电路(symmetricalthree-phase circuit)6.1.82 非对称三相电路(unsymmetrical three-phase circuit)6.1.83 三相电路功率(power of three-phase circuit)6.1.84 非正弦周期电流电路(non-sinusoidal periodic current circuits)6.1.85 基波电流(fundamental current)6.1.86 谐波电流(harmonic current)6.1.87 频谱(frequency spectrum)6.1.88 瞬时值(instantaneous value)6.1.89 平均值(average value)6.1.90有效值(effective value)6.1.91 峰值（peak [value]）6.1.92波形因数(wave factor)6.1.93 总谐波畸变率(total harmonic distortion)6.1.94 平均功率(average power)6.1.95视在功率(apparent power)6.1.96无功功率(reactive power)6.1.97 复功率(complex power)6.1.98 谐波功率(harmonic power)6.1.99 畸变功率(distortion power)6.1.100 伏安(volt ampere)6.1.101 乏(var)6.1.102 瓦特小时(watt hour)6.1.103 串联(series connection)6.1.104 并联(parallel connection)6.1.105 星形阻抗与三角形阻抗的变换(transformation between star-connected and delta connected impedances)6.1.106电源的等效变换(equivalent transformation between sources)6.1.107回路法(loop analysis)6.1.108节点法(node analysis)6.1.109叠加定理(superposition theorem)6.1.110替代定理(substitution theorem)6.1.111 互易定理(reciprocity theorem)6.1.112戴维南定理(Thevenin theorem)6.1.113诺顿定理(Norton theorem)6.1.114 二端口(2-port)6.1.115 特性阻抗(characteristic impedance) 6.1.116 输入阻抗(input impedance)6.1.117 输出阻抗(output impedance) 6.1.118 传播常数(propagation constant)6.1.119 品质因数(quality factor )6.1.120 阻抗匹配(impedance matching)6.1.121 网络函数(network functions)6.1.123 分布参数电路(distributed parameter circuit)6.1.124 一阶电路(first order circuit)6.1.125 二阶电路(second order circuit)6.1.126 高阶电路(high order circuit)6.1.127 非线性电路(nonlinear electric circuit)6.1.128 端子（terminal）6.1.129 端变量（terminal variable）6.1.130 两端(2T) (2-terminal)6.1.131 三端(3T) (3-terminal)6.1.132 四端(4T) (4-terminal)6.1.133五端(5T) (5-terminal)6.1.134四端对(4TP)(4-terminal pair)6.1.135磁场(magnetic field)6.1.136 磁感应强度(magnetic induction)6.1.137磁通量(magnetic flux)6.1.138 磁导率(permeability)6.1.139 相对磁导率(Reletive permeability) 6.1.140磁矩（Magnetic(area) moment）6.1.141 磁化强度（Magnetization）6.1.142 磁极化强度(magnetic polarization) 6.1.143 磁场强度（magnetic intensity）6.1.144磁偶极矩（magnetic dipole moment）6.1.145 磁通势（magnetomotive force）6.1.146 磁阻（reluctance）6.1.147 磁导（permeance）6.1.148 磁化率（magnetic susceptibility）6.1.149 磁共振（magnetic resonance）6.1.150核磁共振（nuclear magnetic resonance）6.1.151霍尔效应（hall effect）6.1.152 波尔磁子（Bohr magneton）6.1.153 质子旋磁比（Proton gyro magnetic ratio）6.1.154 磁通量子（F1ux quantum (F1uxon)）6.2 电学计量6.2.1.1直流电压基准(Primary Standard of DC V oltage)6.2.1.2直流电动势基准(Primary Standard of DC Electromotive Force)6.2.1.3直流电阻基准(Primary Standard of DC Resistance)6.2.1.4电容基准(Primary Standard of Capacitance)6.2.1.5电容器损耗因数基准(Primary Standard of Dissipation Factor)6.2.1.6电感基准(Primary Standard of Inductance)6.2.1.7交流电流基准(Primary Standard of AC Current)6.2.1.8交流电压基准(Primary Standard of AC V oltage)6.2.1.9交流功率基准(Primary Standard of AC Power)6.2.1.10工频电能基准(Primary Standard of AC Energy at Industrial Frequency)6.2.1.11磁感应强度基准(Primary Standard of Magnetic Flux Density)6.2.1.12数字阻抗电桥标准(Standard for LCR meter)6.2.1.13数字多用表检定装置(Standard of Multimeter)6.2.1.14超导强磁场标准(Standard of Supper Conducting High Magnetic Field)6.2.1.15非铁磁金属电导率标准(Standard of Conductivity for Nonferrous Metals)6.2.1.16模/数、数/模转换测量标准（Standard of ADC and DAC）6.2.1.17标准电池(standard cell)6.2.1.18固态电压标准(solid state voltage standard)6.2.1.19标准电阻(standard resistor)6.2.1.20计算电容(cross capacitor)6.2.1.21感应分压器(inductive voltage divider)6.2.1.22分流器(shunt)6.2.1.23直流电流比较仪(direct current comparator)6.2.1.25多功能校准源(multifunction calibrator)6.2.1.26数字阻抗电桥(LCR meter)6.2.1.27 电压表（voltmeter）6.2.1.28 电流表(amperometer)6.2.1.29 电阻表(ohnneter)6.2.1.30 功率表(Watt meter)6.2.1.31 电能表(kWh meter)6.2.2电学计量常用测量方法6.2.2.1 直接测量（法）(direct (method of) measurement)6.2.2.3组合测量（法）(combination (method of) measurement)6.2.2.4 比较测量（法）(comparison (method of) measurement)6.2.2.5 零值测量（法）(null (method of) measurement)6.2.2.6 差值测量（法）(differential (method of) measurement)6.2.2.7 替代测量（法）(substitution (method of) measurement)6.2.2.8 不完全替代法(semi-substitution method of measurement)6.2.2.9 内插测量（法）(interpolation (method of) measurement)6.2.2.10 互补测量（法）(complementary (method of) measurement)6.2.2.11 差拍测量（法）(beat (method of) measurement)6.2.2.12 谐振测量（法）(resonance (method of) measurement)6.2.2.13 模数转换(analogue to digital conversion)6.2.2.14 数模转换(digital to analogue conversion)6.2.2.15 静电屏蔽(electrostatic screen)6.2.2.16 磁屏蔽(magnetic screen)6.2.2.17 泄漏电流(leakage current)6.2.2.18 电位屏蔽(potential screen)6.2.2.19 等电位屏蔽(equip—potential screen)6.2.2.20 无定向结构(astatic construction)6.2.2.21交流-直流转换(AC-DC conversion) 6.2.2.22交流-直流转换器<AC-DC converter) 6.2.2.23交流-直流比较仪(AC-DC comparator)6.2.2.24热电变换器(thermal converter)6.2.2.25 共模电压(common mode voltage)6.2.2.26 串模电压(series mode voltage)6.2.2.27 共模抑制比(common mode rejection ratio ———CMRR)6.2.2.28 串模抑制比(series mode rejection ratio——SMRR)6.2.2.29 非对称输入(asymmetrical input) 6.2.2.30 非对称输出(asymmetrical output) 6.2.2.31 对称输入(symmetrical input)6.2.2.32 对称输出(symmetrical output)6.2.2.33 差分输入电路(differential input circuit)6.2.2.34 接地输入电路(earthed input circuit 或grounded input)6.2.2.35 接地输出电路(earthed output circuit或grounded output)6.2.2.36 浮置输入电路(floating input circuit)6.2.2.37 浮置输出电路(floating output circuit)6.2.3.1 模拟（测量）仪表（analogue (measuring) instrument）模拟指示仪表（analogue indicating instrument）6.2.3.2 数字（测量）仪表（digital (measuring) instrument）6.2.3.3 热电系仪表（electrothermal instrument）6.2.3.4 双金属系仪表（bimetallic instrument）6.2.3.5 热偶式仪表（thermocouple instrument）6.2.3.6 整流式仪表（rectifier instrument）6.2.3.7 振簧系仪表（vibrating reed instrument）6.2.3.8 多用表、万用表（multimeter）6.2.3.9（测量）电桥（(measuring) bridge）6.2.3.10（测量）电位差计（(measuring) potentiometer）6.2.3.11 分压器（voltage divider）6.2.3.12 比较仪（comparator）6.2.3.13 指针式仪表（pointer instrument）6.2.3.14 光标式仪表（instrument with optical index）6.2.3.15 动标度仪表（moving-scale instrument）6.2.3.16 影条式仪表（shadow column instrument）6.2.3.17 静电系仪表（electrostatic instrument）6.2.3.18 磁电系仪表（(permanent magnet) moving-coil instrument）6.2.3.19 动磁系仪表（moving magnet instrument）6.2.3.20 电磁系仪表（moving-iron instrument）6.2.3.21 电动系仪表（electrodynamic instrument）6.2.3.22 铁磁电动系仪表（ferrodynamic instrument）6.2.3.23 感应系仪表（induction instrument）。
磁导率的英文
磁导率的英文一、“磁导率”的英文“磁导率”：permeability或magnetic permeability。
二、英语释义1. The measure of the ability of a material to support the formation of a magnetic field within itself.（一种材料支持其内部磁场形成能力的度量。
）三、短语1. relative permeability（相对磁导率）2. magnetic permeability of free space（真空磁导率）3.plex permeability（复磁导率）四、单词1. permeate（动词，渗透；弥漫；扩散。
与磁导率相关是因为磁导率体现了磁通量在材料中的渗透情况）- The magnetic field can permeate the ferromagnetic material easily.（磁场能轻易地渗透铁磁材料。
）2. magnetic（形容词，磁的；有磁性的）- magnetic field（磁场）五、用法1. 作主语- The permeability of this material is very high.（这种材料的磁导率非常高。
）2. 作介词宾语- Scientists are studying the change of permeability in different environments.（科学家正在研究不同环境下磁导率的变化。
）3. 与形容词搭配使用- The relative permeability of the alloy is an important parameter.（这种合金的相对磁导率是一个重要参数。
）六、双语例句1. The magnetic permeability of iron is much higher than that of air.（铁的磁导率比空气的磁导率高得多。
新干线的英语介绍
新干线的英语介绍The Introduction of Shinkansen (1500 words)Shinkansen, also known as the “Bullet Train”, is a network of high-speed railway lines in Japan. Since its introduction in 1964, the Shinkansen has revolutionized the way people travel, offering a safe, efficient, and comfortable transportation option. This article aims to provide an English introduction to the Shinkansen, discussing its history, technology, features, and impact on Japanese society.1. History of the ShinkansenThe Shinkansen's development was driven by Japan's need for reliable and fast transportation. The first line, known as the Tokaido Shinkansen, was inaugurated in 1964, connecting Tokyo and Osaka. Since then, the network has expanded, covering major cities across the country.2. Shinkansen TechnologyThe Shinkansen utilizes advanced technology to achieve remarkable speed and safety. The trains operate on dedicated tracks, allowing for speeds of up to 320 km/h (200 mph). The tracks are equipped with an Automatic Train Control System, which ensures precise control and maintains a safe distance between trains. The trains themselves are designed with aerodynamic features, reducing air resistance and noise during operation.3. Features of the ShinkansenThe Shinkansen offers a range of features that distinguish it from conventional trains. Firstly, the seats are ergonomically designed formaximum comfort, with ample legroom and adjustable armrests. The trains are equipped with spacious luggage storage areas, providing convenience for travelers. Additionally, the Shinkansen provides a smooth and stable ride, minimizing discomfort and motion sickness.4. Safety and ReliabilityThe Shinkansen has an exceptional safety record, with no passenger fatalities in its history. This is achieved through rigorous maintenance and inspection procedures, as well as advanced safety systems onboard the trains. The track infrastructure is regularly checked for any abnormalities, ensuring a safe and reliable journey for passengers.5. Impact on SocietyThe introduction of the Shinkansen has had a profound impact on Japanese society. It has significantly reduced travel times between major cities, thus promoting economic development and regional integration. The Shinkansen has encouraged people to travel more frequently, leading to increased tourism and cultural exchange. Moreover, the environmental benefits of the Shinkansen, such as reduced carbon emissions and traffic congestion, contribute to a sustainable transportation system.6. Future ExpansionsThe Shinkansen continues to expand its network, with new lines and extensions being planned. The Hokkaido Shinkansen, which extends the line to Japan's northernmost island, was completed in 2016. Furthermore, Japan is actively working on the development of a Maglev (magnetic levitation)train, aiming to achieve even higher speeds and further enhance the transportation system.In conclusion, the Shinkansen is a remarkable achievement in the field of high-speed rail, providing a safe, efficient, and comfortable mode of transportation. Its history, technology, features, and impact on Japanese society make it an integral part of Japan's infrastructure. Whether for business or leisure, the Shinkansen offers travelers an exceptional travel experience.。
功能材料相关文献翻译(中文+英文)
功能材料相关文献翻译（中文+英文）功能材料功能材料是新材料领域的核心，是国民经济、社会发展及国防建设的基础和先导。
它涉及信息技术、生物工程技术、能源技术、纳米技术、环保技术、空间技术、计算机技术、海洋工程技术等现代高新技术及其产业。
功能材料不仅对高新技术的发展起着重要的推动和支撑作用，还对我国相关传统产业的改造和升级，实现跨越式发展起着重要的促进作用。
功能材料种类繁多，用途广泛，正在形成一个规模宏大的高技术产业群，有着十分广阔的市场前景和极为重要的战略意义。
世界各国均十分重视功能材料的研发与应用，它已成为世界各国新材料研究发展的热点和重点，也是世界各国高技术发展中战略竞争的热点。
在全球新材料研究领域中，功能材料约占 85 % 。
我国高技术(863)计划、国家重大基础研究[973]计划、国家自然科学基金项目中均安排了许多功能材料技术项目(约占新材料领域70%比例)，并取得了大量研究成果。
当前国际功能材料及其应用技术正面临新的突破，诸如超导材料、微电子材料、光子材料、信息材料、能源转换及储能材料、生态环境材料、生物医用材料及材料的分子、原子设计等正处于日新月异的发展之中，发展功能材料技术正在成为一些发达国家强化其经济及军事优势的重要手段。
超导材料以NbTi、Nb3Sn为代表的实用超导材料已实现了商品化，在核磁共振人体成像(NMRI)、超导磁体及大型加速器磁体等多个领域获得了应用;SQUID作为超导体弱电应用的典范已在微弱电磁信号测量方面起到了重要作用，其灵敏度是其它任何非超导的装置无法达到的。
但是，由于常规低温超导体的临界温度太低，必须在昂贵复杂的液氦(4.2K)系统中使用，因而严重地限制了低温超导应用的发展。
高温氧化物超导体的出现，突破了温度壁垒，把超导应用温度从液氦( 4.2K)提高到液氮(77K)温区。
同液氦相比，液氮是一种非常经济的冷媒，并且具有较高的热容量，给工程应用带来了极大的方便。
另外，高温超导体都具有相当高的上临界场[H c2 (4K)>50T]，能够用来产生20T以上的强磁场，这正好克服了常规低温超导材料的不足之处。
地球物理学新方法新技术
地球物理学新方法新技术英文回答：In recent years, there have been significant advancements in new methods and technologies in the field of geophysics. These developments have revolutionized the way we study and understand the Earth's physical properties and processes.One of the new methods that has gained popularity is seismic tomography. This technique involves using seismic waves generated by earthquakes or man-made sources to create images of the Earth's interior. By analyzing the travel times and amplitudes of these waves, scientists can map out the subsurface structures and identify geological features such as faults, magma chambers, and mineral deposits. Seismic tomography has been instrumental in improving our understanding of plate tectonics and earthquake hazards.Another exciting development is the use of remote sensing techniques for geophysical exploration. Remote sensing involves collecting data from a distance, typically using satellite imagery or aerial surveys. This approach has proven to be a valuable tool for mapping and monitoring various geophysical parameters, such as land surface temperature, vegetation indices, and soil moisture content. For example, thermal infrared remote sensing can be used to identify areas of potential geothermal energy resources by detecting temperature anomalies at the Earth's surface.Furthermore, advancements in geophysical instrumentation have greatly enhanced data collection and analysis capabilities. For instance, the development of high-resolution magnetometers has allowed for more accurate mapping of the Earth's magnetic field, which is crucial for studying processes such as plate tectonics and geomagnetic reversals. Similarly, the use of ground-penetrating radar (GPR) systems has revolutionized subsurface imaging, enabling scientists to detect buried archaeological structures, underground utilities, and even underground water resources.In addition to these new methods and technologies, computer modeling and data analysis have become indispensable tools in geophysics. Sophisticated software programs can now simulate and analyze complex geophysical processes, such as the behavior of fluids in porous media or the propagation of seismic waves through different geological formations. These models help scientists make predictions and interpret field observations more accurately.Overall, the advancements in new methods and technologies in geophysics have significantly improved our ability to study and understand the Earth's physical properties and processes. These tools have not only enhanced our scientific knowledge but also have practical applications in various fields, such as resource exploration, environmental monitoring, and hazard assessment.中文回答：近年来，地球物理学领域的新方法和新技术取得了重大进展。
Halbach阵列同心式磁力齿轮磁场全局解析法分析
Halbach阵列同心式磁力齿轮磁场全局解析法分析井立兵;章跃进【摘要】针对Halbach阵列同心式磁力齿轮这种内外转子非接触传递的传动装置,运用全局解析法对磁力齿轮内外两层气隙磁场进行分析计算.求解场域划分为内外转子永磁体、内外两层气隙和调磁定子的槽形区域,各子区域的拉普拉斯方程和泊松方程通过边界连续条件建立联系.得到内外两层气隙区域的矢量磁位磁通密度解析表达式,并用计算了内外转子电磁转矩,将气隙磁场波形和内外转子电磁转矩波形分别与二维有限元法计算波形作比较,结果吻合,证明了方法的正确性和有效性.【期刊名称】《电机与控制学报》【年(卷),期】2014(018)010【总页数】6页(P50-54,67)【关键词】全局解析法;Halbach阵列;磁力齿轮;气隙磁场;电磁转矩【作者】井立兵;章跃进【作者单位】三峡大学电气与新能源学院,湖北宜昌443002;新能源微电网湖北省协同创新中心,湖北宜昌443002;上海大学机电工程与自动化学院,上海200072【正文语种】中文【中图分类】TM3510 引言同心式磁力齿轮是一种新型磁力传动装置，其内、外转子为同心式结构，中间采用调磁环对内外转子形成的磁场进行调制，使其具有一定的传动比。
磁力齿轮较传统齿轮具有噪声小、稳定性强、维护成本低和过载自我保护等优点。
所以磁力齿轮已经越来越受到科研人员的重视［1－2］，目前国内外对磁力齿轮进行的理论与实验研究已取得了一些进展［3－4］。
但这种磁力齿轮配备旋转电机更适合用在低转速大转矩的电动汽车［5］和风力发电机上［6］。
气隙磁场分析是电机设计和性能计算的基础。
气隙磁场可以采用解析法或半解析法或数值法(有限元法)求解得到。
有限元法计算精确度高，但计算时间长，且需要以良好的网格品质保证其高精确度。
文献［7］首次提出磁场调制式磁力齿轮机械结构及运行原理，采用磁密频谱分析法研究了气隙中调制磁场的谐波数目及所对应的传动比;文献［8－9］研究了磁力齿轮的结构参数对气隙磁密及转矩特性的影响;文献［10］则基于电动机齿槽转矩原理研究了磁力齿轮如何避免齿槽转矩的产生。
高三科技创新与人类未来英语阅读理解30题
高三科技创新与人类未来英语阅读理解30题1<背景文章>In recent years, technological innovation has been making remarkable strides in the medical field. This has brought about profound changes and also some ethical challenges that are closely related to the future health of humanity.One of the most significant applications of technological innovation in healthcare is in the area of diagnosis. Advanced imaging technologies such as MRI (Magnetic Resonance Imaging) and CT (Computed Tomography) scans have revolutionized the way doctors detect diseases. These high - tech devices can provide detailed internal images of the human body, allowing for earlier and more accurate diagnosis of various conditions. For example, in the case of cancer, early detection through these imaging techniques can significantly increase the chances of successful treatment.Another area where technology has had a great impact is in treatment methods. Robotic - assisted surgeries have emerged as a game - changer. Surgeons can now perform complex procedures with greater precision using robotic arms. These robotic systems are equipped with high - definition cameras and precise instruments, which reduce the risk of humanerror during surgery. Additionally, telemedicine has become increasingly popular. It enables patients in remote areas to receive medical advice from specialists without having to travel long distances.However, along with these great advancements, there are also ethical challenges. For instance, the use of artificial intelligence (AI) in diagnosis raises questions about liability. If an AI - based diagnostic system makes a wrong diagnosis, who should be held responsible? Is it the developers of the algorithm, the medical institution that implemented it, or the doctor who relied on the diagnosis? Another ethical concern is related to gene editing technologies like CRISPR. While it has the potential to cure genetic diseases, there are fears about its misuse, such as creating "designer babies" with specific genetic traits chosen by parents.In conclusion, technological innovation in the medical field is a double - edged sword. It offers great opportunities for improving human health in the future but also requires careful consideration of the ethical implications to ensure that these advancements are used for the benefit of all mankind.1. What is one of the main applications of technological innovation in healthcare according to the passage?A. Developing new drugs.B. Improving hospital facilities.C. Diagnosis.D. Training more medical staff.答案：C。
高梯度立环磁选机选矿工艺流程
高梯度立环磁选机选矿工艺流程英文回答：The high gradient magnetic separator (HGMS) is a mineral processing technique used to separate and concentrate magnetic materials from non-magnetic ones. It utilizes a high gradient magnetic field generated by a magnet to capture and retain magnetic particles while allowing non-magnetic particles to pass through.The process flow of the HGMS mineral processing technique involves several steps. First, the ore is crushed and ground to a suitable size. Then, it is fed into the HGMS system, where the magnetic particles are attracted to the magnetic matrix in the presence of the high gradient magnetic field. The non-magnetic particles pass through the system and are collected separately.Once the magnetic particles are captured by the magnetic matrix, a flushing process is performed to removethe non-magnetic particles and impurities. This istypically done by applying a high-pressure water jet or a combination of water and air. The flushing process helps to clean the magnetic matrix and ensure the efficient separation of magnetic and non-magnetic particles.After the flushing process, the magnetic particles are released from the magnetic matrix and collected in a separate container. This can be achieved by reducing the magnetic field strength or by applying a reverse magnetic field. The collected magnetic concentrate can then undergo further processing or be used directly as a final product.The HGMS mineral processing technique has several advantages. Firstly, it allows for the efficient separation and concentration of magnetic materials, which can be valuable resources. Secondly, it can be used to remove impurities and improve the quality of the final product. Lastly, it is a relatively simple and cost-effective process compared to other mineral processing techniques.中文回答：高梯度立环磁选机（HGMS）是一种用于从非磁性材料中分离和浓缩磁性材料的矿物处理技术。
英语作文介绍东湖高新区
英语作文介绍东湖高新区Introduction to Donghu High-tech Zone。
Donghu High-tech Zone, located in Wuhan, is a national-level high-tech industrial development zone. It covers an area of 50 square kilometers and is home to over 2,000 enterprises, including 18 Fortune 500 companies. It is one of the most important high-tech zones in China.Industry。
Donghu High-tech Zone is a hub for advanced manufacturing, biomedicine, and information technology. It has formed a complete industrial chain in these fields, from research and development to production and sales. The zone has attracted many leading companies, such as Foxconn, Huawei, and China Unicom, to set up research and development centers and production bases here.Innovation。
Innovation is the driving force behind the developmentof Donghu High-tech Zone. The zone has established an innovation ecosystem that integrates industry, academia,and research. It has set up a number of innovation platforms, including the Wuhan National Laboratory for Optoelectronics, the National Engineering Research Centerfor Laser Processing, and the Wuhan National High Magnetic Field Center. These platforms have made significant contributions to the development of high-tech industries in China.Living Environment。
高铁未来的发展中英文作文
高铁未来的发展中英文作文The Future Development of High-speed RailIntroductionHigh-speed rail, also known as bullet train, is a type of rail transport that operates significantly faster than traditional railroads. The development of high-speed rail has been rapid in recent years, with countries around the world investing in this mode of transportation to improve connectivity, reduce travel times, and lower carbon emissions. In this essay, we will explore the future development of high-speed rail and the potential impact it may have on the global transportation industry.Current State of High-speed RailHigh-speed rail has been in operation in several countries for decades, with Japan being the pioneer in this field. The Shinkansen network in Japan began operation in 1964 and has since expanded to cover most major cities in the country. China has also made significant investments in high-speed rail, with the development of the world's largest high-speed rail network. Other countries with extensive high-speed rail networks include France, Germany, Spain, and South Korea.Benefits of High-speed RailHigh-speed rail offers several benefits over other modes of transportation, including:1. Faster travel times: High-speed trains can reach speeds of up to 350 km/h, significantly reducing travel times between cities.2. Environmental benefits: High-speed rail is a more sustainable mode of transportation compared to air travel or driving, as it produces lower carbon emissions per passenger.3. Economic development: High-speed rail can promote economic development by improving connectivity between cities and regions, leading to increased business and tourism opportunities.Future Developments in High-speed RailThe future of high-speed rail looks promising, with several developments and technologies on the horizon:1. Maglev technology: Maglev (magnetic levitation) technology allows trains to float above the tracks, reducing friction and enabling higher speeds. Countries like Japan and China have already implemented maglev trains on certain routes, with plans for further expansion.2. Hyperloop technology: Hyperloop is a proposed mode of transportation that uses magnetic levitation and low-pressure tubes to propel pods at ultra-high speeds. While still in the testing phase, hyperloop technology has the potential to revolutionize long-distance travel in the future.3. Sustainable energy sources: As part of efforts to lower carbon emissions, high-speed rail systems are increasingly turning to sustainable energy sources such as solar and wind power to power their trains.4. Integration with other modes of transportation:High-speed rail networks are being integrated with other modes of transportation, such as airports and metro systems, to provide seamless connectivity for passengers.Challenges and OpportunitiesDespite the many benefits of high-speed rail, there are also challenges that need to be addressed for its future development:1. Cost: Building high-speed rail infrastructure is expensive and requires significant investments from governments and private investors.2. Land acquisition: Acquiring the land needed to build high-speed rail lines can be a complex and time-consuming process, especially in densely populated areas.3. Competition from other modes of transportation:High-speed rail faces competition from airlines, cars, and buses, which offer lower fares and greater flexibility in terms of routes and schedules.4. Safety concerns: Ensuring the safety and reliability of high-speed trains is crucial to gaining public trust and encouraging ridership.ConclusionHigh-speed rail has the potential to transform transportation networks and improve connectivity between cities and regions. With ongoing developments in technology and infrastructure, high-speed rail is set to play a key role in the future of transportation. By addressing challenges and seizing opportunities, countries can harness the full potential ofhigh-speed rail to create a more sustainable and efficient transportation system for future generations.。
乳腺弥散加权成像的原理和临床应用-医学精品
Introduction
• Diffusion-weighted imaging was initially applied in the clinical setting in the mid-1990s for the diagnosis of acute stroke. At that time, diffusion-weighted imaging demonstrated a high diagnostic utility, not only in the investigation of acute stroke, but also in developing the differential diagnosis for other brain abnormalities, including tumors and abscesses.
Diffusion-weighted Imaging of the Breast: Principles and Clinical Applications
乳腺弥散加权成像：原理和临床应用
何杰 2019年12月25日
Introduction
• Diffusion-weighted imaging is a modality that makes use of magnetic resonance (MR) imaging to depict the diffusivity of water molecules in a defined voxel by means of the application of motion-probing gradients. This imaging property is unique and provides a different contrast mechanism than that observed on conventional T1- and T2weighted MR images. Evaluation of breast images acquired with sensitization to the diffusion of water molecules has the potential to play an adjunct role in the assessment of breast tissue.
关于电动机的英语论文
Introduction of motorAbstractMotor is a device that converts electrical energy into mechanical energy. It is through the coil (is the stator windings) generated rotating magnetic field and the role of forming a magnetic force rotating torque to the rotor (such as the mouse cage closed aluminum frame). Motor by using the power of DC motor and AC motor, motor power system mostly AC motor and can be synchronous motor or is asynchronous motor (motor stator magnetic field speed and rotor rotating speed does not maintain synchronous speed). The motor is mainly composed of stator and rotor, the direction of the force movement in the magnetic field is related to the direction of the current and the direction of the magnetic field (magnetic field). The working principle of the motor is the effect of the magnetic field on the current force, which makes the motor rotate.Key words: Motor ; power ; magnetic field ; currentBasic parameterProcess of inventionMotor using the pass electrical conductor in a magnetic field by the principle of force (this is different on the argument that the magnetic effect of electric current, the current teaching version of ninth grade physics clearly to separate the two), found that this principle is the Danish physicist, OE, 1777 August 14, was born in Lange Ron Arudejobbin a pharmacist family. Admitted to University of Copenhagen in 1799, received a doctorate in 1794. From 1801 to 1803 to Germany, France and other countries to visit, met many physicists and chemists. In 1806 he was appointed professor of physics at the University of Copenhagen, in 1815 he was appointed Permanent Secretary of the Royal Society of denmark. In 1820 due to current magnetic effect this extraordinary discovery by the British Royal Society Copley medal.Since 1829, he served as president of the Copenhagen Institute of technology. Died in Copenhagen in March 9, 1851. He has studied physics, chemistry and philosophy in many aspects. Owing to the influence of Kant's philosophy and the natural philosophy of Xie Lin, it is believed that natural forces can be transformed into each other, and to explore the relationship between electricity and magnetism in the long term. April 1820 finally found the current of the magnetic needle, namely current magnetic effect. In July 21st of the same year with the theme of "the effect of electric needle on the conflict" published his findings. This short paper caused great shock to the European physics community, which led to the emergence of a large number of experimental results, which opened up a new field of Physics - a new field of physics.In 1812, he first proposed the idea of the connection between light and electromagnetism. In 1822, he studied the compressibility of liquids and gases. 1825 refined aluminum, butthe purity is not high. In the study of acoustics, he tried to find out the electric phenomenon caused by sound. His last research work was magnetic. He is an enthusiastic attention to scientific research and experiment of the teacher, he said: "I don't like the way that no experimental boring lectures, all scientific research from the beginning of the experiment of". So popular with students. He was also an excellent speaker and natural science popularization worker, in 1824, the establishment of the Danish Association for the promotion of science, created the first Danish physics laboratory. In 1908 the establishment of the association "oersted Medal" to promote the Danish Natural Sciences, in recognition of the significant contribution of physicists. Named 1934 unit of magnetic field in the CGS unit to "OE". 1937 American Association of physics teachers set up a "oersted Medal", physics teacher reward to make a contribution in physics teaching.In 1821, Faraday completed the first major electric invention. In the past two years before, OE have been found if current passes through the circuit, it in the vicinity of the ordinary compass needle will shift. Faraday was inspired by the thought that if the magnet is fixed, the coil may be moving. According to this idea, he succeeded in inventing a simple device. In the device, as long as there is current through the line, the line will turn around a magnet. In fact Faraday invented the first electric motor, which was the first device to use electric current to move the body. Although the device is simple, but it is today in the world to use the ancestors of all motors.This is a major breakthrough. But its practical use is very limited, because at that time there is no other way to generate electricity in addition to the simple battery.Development present situationChina's motor production began in 1917, the industry has formed a relatively complete industrial system in the country. With the development of electric power industry, the electric motor manufacturing industry in our country has shown great vitality, and the scale of production and marketing and the economic efficiency have been greatly improved.2005-2011 years, China's motor manufacturing industry sales revenue increased by an average of 36.92%. In addition to the affected by the financial crisis in 2009, general downturn in manufacturing, motor year-on-year growth rate fell to 11.20% outside, other years, the market size of China's motor growth rate are in high level, an average in more than 20%, even in 2011, China's manufacturing industry, the pace of development of a general slowdown in under, motor year-on-year growth still reached 21.87%.Motor manufacturing enterprises should establish their own brands, the force of high-end, expand overseas markets, guarantee product quality and after-sales service, to the development of navigation, aviation, military industry, nuclear power and special motors, such as new areas, in order to in the fierce market competition in an invincible position.In the whole society electricity consumption, about 70% of consumption in the industrial field, and the power consumption of the motor industry and occupy the entire industry of electricity 70%. To improve the efficiency of the motor can be mainly through 2ways, through a frequency converter, AC motor to improve the operation efficiency; two is the use of high efficiency motors. The frequency converter is different such main industry, energy efficiency is more than 30%, in some of the industry even as high as 40%-50%. Efficient motor market application proportion is still relatively low, but the minimum energy efficiency standards and subsidies to support future efficient motor market application proportion will rise sharply.2012 1-12 months, China's total exports of electric motors and generators 3 billion 96 million units, compared with the same period in 2011 reduced by 8.2%, total exports amounted to $9 billion 224 million, an increase of 5%. The month of December, China's exports of electric motors and generators for 274 million 800 thousand Taiwan, exports amounted to $818 million. In the investment, it should be before the introduction of favorable policies in advance layout. Efficient motor market applications are still low, but in the minimum energy efficiency standards and subsidies to support the future, the future efficiency of the market will be a substantial increase in the proportion of motor market. The motor system comprises a control device, motor, drag device, transmission device and network load, is a complex system involving multidisciplinary and multi field.Strategic emerging industries, contract energy management policy, market-oriented energy-saving environmental protection service system construction, comprehensive utilization of resources and remanufacturing and energy-saving products Huimin engineering, motor is extended to the motor industry development has brought great opportunities, and the motor manufacturers and motor supporting enterprises also ushered in the renewal of product market growth potential. Especially in order to adapt to the low carbon economy era of energy saving technology innovation trend, high efficiency motor has gradually become the mainstream of the future market.China's motor more than 2 trillion kwh electricity, accounting for about 60% of electricity consumption and industrial consumption 80%. High efficiency motor energy consumption than ordinary motor lower 20% ~ 30%, but in our country, motor market share of only 10%, so vigorously promote efficient motor will be for the country to promote energy-saving emission reduction has a certain significance, the potential market opportunities also emerging.Although there are many kinds of motor products in our country, but the efficiency is not high, there is a serious phenomenon of "big horse drawn cart", and the promotion and application of high efficiency motors have no time to delay. China's "Twelfth Five Year Plan" period will concentrate around the motor system energy-saving projects, equipment manufacturing restructuring and revitalization, new energy technical field vigorously promote optimization development of a group of highly efficient energy saving and environmental protection of key products, eliminated a number of general efficiency of motor products, to promote the upgrading of products. In the high energy behind the mechanical and electrical equipment ministry announced the "(product) out of the directory (second batch)", the electrical equipment list, indicating that China's motor industry will face a new development of the market and technology.To effectively eliminate inefficient motors, speed up the promotion of efficient motors, the National Standardization Management Committee issued version of the small three-phase asynchronous motor energy efficiency limit value of energy efficiency andenergy efficiency grades "in the implementation of the national standard in September 2012, small motor industry faced with greater impact. At present, China's mass production of Y, Y2, Y3 series three-phase asynchronous motor will be prohibited from production, enjoy the national Hui Min project YX3 series of high efficiency three-phase asynchronous motor will likely no longer receive policy subsidies. Efficient motor research and development and promotion is like the arrow, the industry is concerned about an unprecedented degree of attention.Startup modeMotor starting methods include: full pressure direct start, self coupling decompression starting, y- delta starter, soft starter, inverter.Full pressure direct start：In the power grid capacity and load two are allowed to direct starting pressure, total pressure can be used direct starting. Manipulation of advantage is easy to control, simple maintenance, and more economical. Mainly used for small power motor starting, from the point of view of energy conservation, more than 11kw of the motor is not suitable to use this method.Self coupling decompression starting：By using the multi tap decompression of the self coupling transformer, it can not only adapt to the need of different load starting, but also get a larger starting torque. It is a reduced starting method which is often used to start large capacity motor. The biggest advantage is that the starting torque is larger, when the winding tap in 80%, the starting torque can reach 64%. And the starting torque can be adjusted by the tap. So far is still widely used.Y- Delta starting：For the normal operation of the stator winding is connected in a triangle method of squirrel cage asynchronous motor, if the stator windings are connected into a star at the start, after waiting for after the start and delta connected, you can reduce the starting current, and reduce its impact on the power grid. This starting method is called star delta decompression starting, or short for star delta starting (y- delta starting). When starting the star delta, the starting current is the original 1/3. If the starting current is 6 to 7ie, the starting current is 2 to 2.3 times. This means that the starting torque is reduced to 1/3 when the starting torque is directly started by the triangle method. Suitable for no load or light load starting. And compared with any other decompression starter, the structure is simple and the price is the cheapest. In addition, the star delta starting mode has an advantage, that is, when the load is light, the motor can be operated in the star connection method. At this point, the rated torque and the load can be matched, so that the efficiencyof the motor can be improved, and the power consumption is saved.Soft starter：This is the use of a phase shifted controlled silicon pressure principle to realize motor voltage starting, mainly used for motor starting control, start effect is good but the cost is high. Because of the use of SCR thyristor when the harmonic interference is large, has a certain impact on the power grid. In addition the grid fluctuations will also affect the thyristor conduction, especially a plurality of controllable silicon in the same power grid equipment. So the SCR fault rate is higher, because it involves the power electronic technology, so the maintenance staff requirements are also higher.Frequency converter：Inverter is the highest technology content in the field of modern motor control, control function of the most complete, the best control effect of the motor control device, which by changing the frequency of the power grid to adjust the speed and torque of the motor. Because it involves power electronic technology, computer technology, high cost, maintenance of technical personnel is also high, so it is mainly used in the need for speed control and high speed control requirements of the field.Speed regulating methodA lot of motor speed control method, can adapt to the change of the speed of different production machinery. The general motor speed when the output power will change with speed. From the point of view of energy consumption, speed control can be roughly divided into two kinds:(1) Keeping the input power constant. By changing the energy consumption of thespeed regulating device, the output power is adjusted to adjust the speed of the motor.(2) Control the input power of the motor to adjust the speed of the motor. Motor, motor,brake motor, variable frequency motor, variable speed motor, three-phase asynchronous motor, high voltage motor, multi speed motor, two speed motor and explosion proof motor.Structure classificationBasic structure一、The structure of a three-phase asynchronous motor is composed of a stator, a rotor and other accessories.（一）stator (stationary part)1、 stator coreFunction: part of the magnetic circuit of the motor, and the stator winding is arranged on the motor.Structure: the stator core is made of silicon steel sheet with insulation layer on the surface of 0.35~0.5 mm thick, which is formed by punching and laminating.There are several types of stator core slot：Semi closed type slot：motor efficiency and power factor is higher, but the winding embedding and insulation are more difficult. Generally used in small low voltage motor.Semi open slot：can be embedded into the shape of the winding, generally used for large, medium and low voltage motor. The winding is winding can advance through insulating treatment and then into the groove.The opening slot: to embed the winding insulation, convenient method, mainly used in high voltage motor.2、 stator windingFunction：is the circuit of the motor, through the three-phase alternating current, generating a rotating magnetic field.Structure：120 in the space of each other three degrees electric angle, symmetrical arrangement of the structure of the same winding connection, the coils of these coils are embedded in the stator slot.The main insulation of the stator winding project has the following three kinds: (to ensure that the conductive part of the windings and the reliable insulation between the core and the reliable insulation between the windings).a、 Ground insulation：insulation between stator windings and stator core.b、 Interphase insulation：insulation between the stator windings of each phase.c、 Turn to turn insulation：insulation between turns of each line of each phase of thestator winding.Connection in motor terminal box：Motor terminal box has a wiring board, three-phase windings of the six thread arranged on two rows, and the provisions of row three wiring pile from left to right order number for 1 (U1), 2 (V1), 3 (W1), row three wiring pile from left to right order number for 6 (W2), 4 (U2), 5 (V2). The three-phase windings are connected into a wye connected or connected in a triangle. Where manufacturing and maintenance should be in accordance with this sequence number.3、 seatFunction:：the fixed stator core and the front and back end cover to support the rotor, and the role of protection, heat dissipation and so on.Structure:：frame is usually cast iron parts, large asynchronous motor base general welding steel plate into, the miniature motor base used aluminum pieces. Closed type motor base outside the radiating ribs to increase the heat dissipation area, protection ofthe motor frame at both ends of the end cover is provided with a ventilation hole, inside and outside the motor of air forced convection direct, to facilitate heat dissipation.（二）Rotor (rotating part)1、 Rotor core of three phase asynchronous motor：Role:：as part of the magnetic circuit of the motor and the rotor winding in the iron core slot.Structure：the material used is the same as the stator, by the 0.5 mm thick steel sheet punching, lamination, silicon steel sheet with a uniform distribution of the hole, used to place the rotor winding. The stator core is usually used to flush the rotor core with the inner circle of the silicon steel sheet which is backward in the stator core. The rotor iron core of the general small asynchronous motor is directly pressed on the rotating shaft, and the rotor core of the large and medium-sized asynchronous motor (rotor diameter is in 300~400 mm or more) is pressed on the rotating shaft by means of the support and the rotor support.2、 Rotor winding of three-phase asynchronous motor：Function：cutting stator rotating magnetic field generated induction electromotive force and current, and the formation of electromagnetic torque and the motor rotation.Structure：divided into squirrel cage rotor and wound rotor.a：The squirrel cage rotor, rotor winding by inserting a plurality of rotor in the groove of the guide bar and two ring end ring. If you get rid of the rotor core, the winding is shaped like a squirrel cage type winding, it said. Small squirrel cage motor with cast aluminum rotor winding, the above 100KW motor adopts copper and copper end rings welded.b：Wound rotor type: winding rotor winding and the stator windings is similar, is a symmetrical three-phase winding, general access into a star and three outlet end is connected with a rotating shaft of the three collector, through the brush is connected with the external circuit.Features: the structure is more complex, so the application of wire wound motor is not as wide as the squirrel cage motor. But the collector ring and brush in rotor winding loop on into additional resistance element, to improve the asynchronous motor, braking performance and speed regulation performance, so in a certain range of smooth speed regulation equipment, as above, such as cranes, elevators, air compressor used.（三）Other accessories for a three phase asynchronous motor1、 end cap: support.2、 bearing: connecting the rotating parts and fixed parts.3、 bearing cover bearing protection.4、 fan cooled motor.二、The DC motor is used in the automatic control technology of the positive and reverse automatic control technology. According to the needs of users can also be madewith a series of winding. The center of 100 ~ 280mm without compensation winding motor, but the center of the motor with high 250mm, 280mm according to the specific circumstances and needs can be made with compensation winding, center height of 315 ~ 450mm motor with compensation winding. The center height of 500 ~ 710mm motor dimensions and technical requirements are in line with the international standard of IEC, the mechanical tolerances of motor in accordance with the ISO international standard.matters needing attention（1）Before removing, use compressed air to blow the dust on the surface of the motor, and clean the surface of the dirt.（2）Select the motor disintegration of the work place, clean up the site environment. （3）Familiar with motor structure characteristics and maintenance technical requirements.（4）Ready to collapse the required tools (including special tools) and equipment. （5）In order to further understand the defects in the motor operation, the conditions can be done before the demolition of a check test. Therefore, the motor load test, detailed examination of the motor parts temperature, sound, vibration and test voltage, current, speed, then disconnect the load, alone with a no-load test, measure the no-load current and no-load loss, make a record.（6）Cut off the power supply, remove the motor external connection, do a good job of recording.（7）Choose the appropriate voltage megger insulation resistance test. In order to repair the insulation resistance with the last measured value compared to determine the motor insulation insulation and trends, should be measured under different temperature of the insulation resistance value is converted into the same temperature, the general conversion to 75 DEG C.（8）Test absorption ratio K. When the ratio of absorption is greater than 1.33, it shows that the insulation of the motor is not affected with damp or damp. In order to compare with the previous data, the same to be measured at any temperature absorption ratio is converted to the same temperature.Application applicationAmong all kinds of motor, the most widely used is the AC asynchronous motor (also known as induction motor). It is easy to use, reliable operation, low price, strong structure, but the power factor is low, the speed is also more difficult. The synchronous motor not only has high power factor, but also has nothing to do with its speed and load, and only depends on the frequency of the power grid. Work more stable. Multi use DC motor in the demand of wide range speed regulation. But it has commutator, complex structure, expensive, difficult to maintain, not suitable for harsh environment. After 1970s, with the development of power electronics technology, AC motor speed control technology is becoming mature, the price of equipment is increasingly lower, has begun to be applied. Motor under the provisions of the standard (continuous, short-term operation system,intermittent cycle run) can bear so as not to cause the maximum mechanical output power of the motor overheating said its rated power, use need attention to the provisions on the nameplate. When the motor is running, it is necessary to pay attention to the characteristics of the load to match the characteristics of the motor. The motor can provide a wide range of power, from the MW level to the million kilowatt class. The use and control of the motor is very convenient, self starting, acceleration, braking, reverse, brake live ability. General motor speed, the output power will change with the speed.Over the past decade, the Chinese government is committed to promoting the motor speed control technology, all walks of life to a certain extent, the use of the motor speed. According to the oil, electricity, building materials, steel, nonferrous metals, coal, chemical, paper, textile and other departments of the enterprise sampling survey results, petroleum, building materials, chemical industry, the application of motor speed. In the 400 million kW motor load, about 50% is the load change, 30% of which can be solved by the motor speed adjustment of the load changes. Therefore, only on the market capacity considerations, about 60 million kW of the motor market. China's various types of motor installed capacity has more than 400 million kW, which accounts for about 90% of asynchronous motor, small and medium motors accounted for about 80%, drag the fan pump and compressor machinery of the motor about kW. Medium and small motors have more than 152 series, 842 varieties, more than 4000 specifications. In the past 10 years, machinery industry and other relevant departments to vigorously grasping energy saving work of the motor, organization and leadership of the relevant research institutes and enterprises, has designed and manufactured a variety of energy-saving motor, and explicitly issued out of the 63 species of high energy motor and promotion of 24 kinds of energy-saving motor and achieved certain results. These energy-saving products are mainly divided into two categories: one is to improve the efficiency of motor efficient motor, and the other is the speed control motor.advantageBrushless DC motor from the main motor and drive components, is a kind of typical mechatronic products. Motor stator windings made more symmetrical three-phase star connection, with the three-phase asynchronous motor is very similar. The rotor of the motor is stuck have been magnetized permanent magnet. In order to detect motor rotor polarity, in the motor with position sensor. Drive is composed of power electronic devices and integrated circuit, its function is to accept the motor start and stop, brake signal, to control the motor start and stop and braking; accept the position sensor signals and positive and negative signals, used to control on-off of the inverter power tube, continuous torque; accept speed instructions and speed feedback signal, used to control and adjust the speed; provide protection and display and so on.Because the brushless DC motor is controlled, so not like frequency control under heavy load starting of synchronous motor as on the rotor plus the startup winding nor in the mutation load produced vibration and losing step. The small volume of Brushless DC motor with permanent magnet, NdFeB rare earth high magnetic energy product (Nd-Fe-B) materials. Therefore, the rare earth permanent magnet brushless motor reduce thevolume of a frame size than the same capacity of three-phase asynchronous motor. Nearly thirty years for asynchronous motor variable frequency speed regulation research, in the final analysis, is looking for asynchronous motor torque control, rare earth permanent magnet brush DC motor is bound to its wide speed, small volume, high efficiency and steady state speed error small characteristics appeared in the field of speed advantages. Brushless DC motor because with DC brush motor characteristics, and also the device as well as the change of frequency, so also known as DC inverter, the general term for the BLDC no brush DC motor operating efficiency, low speed torque speed precision are than any control technique of inverter better, so it is worth of concern to the industry. This product has already produced more than 55kW, can be designed to 400kW, can solve the industrial sector power saving and high performance driven demand.参考文献【1】李光中《电机及电力拖动》机械工业出版社2013-1 【2】孙克军《电动机的使用与维修》化学工业出版社2008-5 【3】王益全《电动机原理与实用技术》科学出版社2005-7ConclusionMotor from the development so far, the advent of a generation of products is around the basic working principle and development and how to operation and maintenance of the motor is the top priority of our working on at the moment. Motor plays an important role in our country's economic construction. As our country joins WTO, the international community's great competitive pressure and challenge of the international community is becoming more and more important. From the energy conservation, environmental protection, high efficiency motor is currently the trend of international development. It appears that the promotion of China's high efficiency motor is very necessary.。
材料化学英文
材料化学英文Material Chemistry。
Material chemistry is a branch of chemistry that focuses on the study and development of materials with desirable properties. It is an interdisciplinary field that combines principles of chemistry, physics, and engineering to design and create new materials for various applications. The understanding of the structure-property relationships of materials is crucial in material chemistry, as it allows scientists to tailor the properties of materials to meet specific needs.One of the key areas of interest in material chemistry is the development of advanced materials for energy storage and conversion. With the increasing demand for clean and sustainable energy sources, there is a growing need for high-performance materials for batteries, fuel cells, and solar cells. Material chemists are working on the design and synthesis of new materials with improved energy storage and conversion efficiency, as well as enhanced stability and durability.Another important aspect of material chemistry is the development of functional materials for electronics and optoelectronics. The rapid advancement of technology has led to the demand for materials with unique electronic and optical properties. Material chemists are exploring the synthesis of novel semiconducting, magnetic, and photonic materials for applications in electronic devices, sensors, and displays.In addition to energy and electronics, material chemistry also plays a crucial role in the development of advanced materials for healthcare and biotechnology. Biomaterials, such as biodegradable polymers and tissue-engineering scaffolds, are being designed to improve medical implants and drug delivery systems. Furthermore, the development of nanomaterials for diagnostic imaging and targeted therapy is a growing area of research in material chemistry.The field of material chemistry is constantly evolving, driven by the demand for new materials with improved performance and functionality. Advances in synthesistechniques, characterization methods, and computational modeling have enabled material chemists to design and create materials with unprecedented properties. The integration of nanotechnology and advanced manufacturing processes has also opened up new possibilities for the development of next-generation materials.In conclusion, material chemistry is a dynamic and interdisciplinary field that plays a critical role in the development of advanced materials for various applications. From energy storage and electronics to healthcare and biotechnology, material chemists are at the forefront of creating innovative materials with tailored properties. The ongoing research and development in material chemistry will continue to drive the advancement of technology and address the global challenges of the 21st century.。
高新技术转化成果 英语
高新技术转化成果英语High-Tech Transformation AchievementsWith the rapid development of science and technology, high-tech achievements are constantly emerging in various fields. These achievements not only promote technological progress but also bring about tremendous changes in people's lives. In this article, we will explore some remarkable high-tech transformation achievements and their impact on society.One of the most significant high-tech transformation achievements is in the field of healthcare. Advanced medical imaging technologies, such as magnetic resonance imaging (MRI) and computed tomography (CT), have revolutionized the way diseases are diagnosed. These technologies provide detailed images of internal organs, allowing doctors to accurately identify and treat various conditions. Furthermore, the development of robotic surgery has made minimally invasive procedures possible, reducing patient trauma and improving surgical outcomes.In the field of transportation, the emergence of electric vehicles (EVs) has brought about a major revolution. EVs are powered by electricity stored in rechargeable batteries,eliminating the need for fossil fuels. This not only reduces greenhouse gas emissions but also helps to tackle the issue of air pollution. Moreover, the advancement of self-driving technology has the potential to transform the entire transportation industry. Autonomous vehicles can enhance road safety, improve traffic efficiency, and provide more accessible transportation options for people with limited mobility.Another notable high-tech transformation achievement lies in the realm of communication. The invention of smartphones has completely changed the way people connect and access information. With a smartphone, individuals can make calls, send messages, browse the internet, and use various applications all in one device. This has greatly increased the efficiency of communication and has made information more accessible than ever before. Additionally, the development of 5G technology promises faster and more reliable internet connections, enabling seamless communication and facilitating the Internet of Things (IoT) revolution.In the field of energy, renewable energy technologies havemade remarkable progress in recent years. Solar energy, wind energy, and hydropower are all clean and sustainable alternatives to traditional fossil fuels. The widespread adoption of these renewable energy sources has the potential to reduce greenhouse gas emissions and mitigate the impacts of climate change. Moreover, the advancements in energy storage technologies, such as lithium-ion batteries, have made it possible to store and utilize renewable energy more efficiently, further promoting the transition towards a greener future.In conclusion, high-tech transformation achievements have had a profound impact on various aspects of society. From healthcare to transportation, communication to energy, these advancements have brought about significant improvements and positive changes. However, it is important to recognize that the responsible and ethical use of these technologies is equally crucial. As we continue to embrace and develop high-tech innovations, it is essential to ensure that they are utilized for the betterment of humanity and the sustainability of our planet.。
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
Development of high magnetic field superconducting magnettechnology and applications in ChinaQiuliang Wang a,*,Yingming Dai a ,Baozhi Zhao a ,Shouseng Song a ,Yuanzhong Lei a ,Houseng Wang a ,Bai Ye a ,Xinning Hu a ,Tianbing Huang a ,Hui Wang a ,Chu He a ,Muxi Shang a ,Chao Wang a ,Chunyan Cui a ,Shangwu Zhao a ,Quan Zhang a ,Yanhua Diao a ,Yan Peng a ,Guoxin Xu a ,Fanping Deng a ,Peide Weng b ,Guangli Kuang b ,Bingjun Gao b ,Liangzhen Lin a ,Luguang Yan aaApplied Superconductivity Laboratory,Institute of Electrical Engineering,Chinese Academy of Sciences,P.O.Box 2703,Beijing 100080,PR ChinabInstitute of Plasma Physics,Chinese Academy of Sciences,PR ChinaReceived 1June 2006;received in revised form 8October 2006;accepted 25April 2007AbstractHigh magnetic field superconducting magnet technology has been developed in the recent years for all kinds of applications in China.The superconducting magnets on the basis of the conduction-cooled high (HTS)and lower temperature superconductor (LTS)through GM cryocooler are designed,fabricated and operated for the magnetic separator,superconducting magnet energy storage system (SMES),material processing,gyrotron,electromagnetic launcher,space anti-matter detection,magnetic surgery system (MSS),heavy ion accelerator dipole magnet and test bed for characteristics of superconducting material in Institute of Electrical Engineering,Chinese Academy of Sciences (IEECAS).The EAST superconducting Tokamak is being fabricated in Institute of Plasma Physics,Chinese Acad-emy of Sciences.In the paper,we report the successful development of high magnetic field superconducting magnet technology in China.Some new research projects,such as 40T hybrid magnet,25T high magnetic field superconducting magnet,split-pair magnets for the pallation Neutron Source,high temperature superconducting coils for MSS and MRI are introduced.Ó2007Elsevier Ltd.All rights reserved.Keywords:High magnetic field;Superconducting magnet;Conduction-cooled;High temperature superconductor1.IntroductionThe superconducting magnets generated the high mag-netic field for some special applications have been devel-oped since 1970in IEECAS,China.Significant progress on high magnetic field superconducting magnet has been achieved for the practical applications.In the recent years,the conduction-cooled superconducting magnets have been rapidly developed to lead to a lots of new applications.This technology provides access to high magnetic fields in appli-cations or locations where the use of liquid helium is diffi-cult or expensive [1].Many areas of research have benefited from the applications of this kind of superconducting magnets.The superconducting magnets on the basis of the conduction-cooled high (HTS)and lower tempera-ture superconductor (LTS)through GM cryocooler are designed,fabricated and operated for the magnetic separa-tor,SMES,material processing,gyrotron,electromagnetic launch,space anti-matter detection,MSS and heavy ion accelerator dipole magnet by IEECAS.The development of the first conduction-cooled super-conducting magnet was finished in 1999in China.After that,the conduction-cooled superconducting magnets for the material processing devices,the high power microwave0011-2275/$-see front matter Ó2007Elsevier Ltd.All rights reserved.doi:10.1016/j.cryogenics.2007.04.023*Corresponding author.Tel.:+861062657243;fax:+861062542034.E-mail addresses:qiuliangw@ ,qiuliang@ (Q.Wang)./locate/cryogenicsCryogenics 47(2007)364–379applications and electromagnetic launcher have been designed,fabricated and tested.The high temperature superconducting(HTS)magnets of Bi-2223tape based on the double-pancakes were fabricated and tested for the high gradient magnetic separator in the industry wasted-water treatment and small scale SMES magnet cooled by solid-nitrogen.The projects were supported by the national high technology program in China(863program).IEE-CAS is taking part in the international cooperation pro-gram about the alpha magnetic spectroscopy(AMS)to develop aluminum stabilized superconducting magnet based on super-fluid helium with heat exchanger cooled. The magnet with12racetrack-shaped and dipole coils will be used in the space anti-matter detection.It will be launched through space shuttle to send to international space station in2008.A large test cryostat for super-fluid helium has been designed and fabricated for ground test of the AMS magnet.A cryogenic test bed for high-amper-age characteristics of high temperature superconducting wires and test coils has been designed and will be fabri-cated.EAST fusion device is a national large scientific pro-ject for fabricating a superconducting Tokamak.The device is designed and fabricated by the Institute of Plasma Physics,Chinese Academy of Sciences.A New National Program will be started in next5years in China.Some new projects for the high magneticfield technology,such as40T hybrid magnet,25T high magneticfield supercon-ducting magnet,split-pair superconducting magnet for the HTSpallation Neutron SourceTH(SNS),HTS magnet sur-gery system with hemi-spherical shaped coils,MgB2super-conductor for medical MRI and special applications will be supported by the government.2.Development of conduction-cooled superconducting magnet system for material processingThe10T superconducting magnet system consists of a Nb3Sn coil fabricated using/1.0mm superconducting wire generating a centerfield of3.96T and two NbTi coils with inner and outer coils fabricated using/1.0mm,0.65mm superconducting wire,respectively.Fig.1shows the config-uration of the conduction-cooled superconducting magnet[2].The NbTi coils can provide the centerfield of6.04T.A stainless steel former is employed for the Nb3Sn coil to support the electromagnetic force.In order to improve the thermal connection for between the superconducting coils and GM cryocooler,a brass former is used for the NbTi superconducting coils.The former is with a2mm width slot along axis to reduce the eddy losses during the charge of the magnets.The Nb3Sn and NbTi superconduc-ting coils are connected to the same power supply.The operating current of magnet system is116A.The main parameters of the magnet system are listed in Table1. The maximum operating temperature in the superconduc-ting magnet is defined as5K due to ramping rate to gener-ate the AC losses in superconducting wire[3].The operating currents to its critical currents for NbTi super-conducting coils are79.2%for inner coil and59%for the outer coil.The operating current for Nb3Sn is equal to about75.5%I C(where I C is the critical current of short sample in Nb3Sn).The NbTi superconducting coils are fab-ricated by wet winding technology and impregnated with epoxy resin DW-3.The outer size of the vacuum cryostat is about742mm in diameter and558mm in height.The total weight of the system is about180kg.The superconducting magnet is sus-pended in the vacuum cryostat by epoxy-resin bars.The Bi-2223high temperature oxide superconducting current leads are used to reduce heat conduction to the superconducting magnet and are directly cooled by a Gifford–McMahon two stages refrigerator.The second-stage is used for cool-ing magnet.The temperature of the superconducting mag-net is monitored to protect the magnet from the damage caused by quench of the superconductors.The magnet is maintained at the temperature blow4.2K during the oper-ation.The cryostat consists of cooling shield,superinsula-tion,pull rod,thermal connection and inner dewar pipes. The cryostat is constructed using stainless steel.It has an outer vacuum vessel on which is mounted the cryocooler which cools the40K radiation shield and the magnet to 4K or less.The total heat load at the second stage of cryo-cooler is about0.4W.The total heat leak in thefist stage of the cryocooler is about14.0W.The GM cryocooler used in the magnet is conventional and commercially available from Sumimoto RDK-408D.The cooling capacity of the refrigerator is31W at40K on thefirst stage and1W at 4.2K on the second stage,respectively.In order to reduce the temperature rise during charging the magnet,a thermal reservoir which consists of the helium gas under pressure in a vessel connected by afine tube between the vessel and the magnet is employed.The helium gas in the vessel will be cooled to the liquid helium while the magnet is cooled to operating temperature.During charging the magnet to gen-erate the AC losses in superconducting magnet,the heat will remove from the magnet to the thermal reservoir.The cold-press technology is used for the superconduc-ting joint for NbTi-to-NbTi.The joint was testedunder Fig.1.Configuration of the superconducting magnet.Q.Wang et al./Cryogenics47(2007)364–379365the backgroundfield of5T and operating temperature of 4.2K.The critical current for the joint is over130A.A HTS pipe around the joint is used to shield the magnetic field.Five temperature sensors are attached on the radia-tion shield,first stage,top and bottom of superconducting magnet.There is an electronic instrumentation port for magnet current leads and temperature sensors.The central bore of the magnet may be at room temperature or it can befitted with a high temperature furnace for material processing.The superconducting magnet system includes the power supply,protection,cryocooler and control.The vacuum of cryostat was measured to9·10À4Pa before the supercon-ducting magnet is cooled.Fig.2shows the cooling process for magnet system.The temperatures of the magnet are about4.17K for top and4.16K for bottom of the super-conducting magnet after about76h,and the temperatures of thefirst and second stage cool-head are about3.4K and 32.88K,respectively.Fig.3shows the profiles of tempera-tures in the magnet,cryocooler and charging current with respect to time.The maximum charging current is115A. After operation of40h,a mistake active from protection circuit results in the current decaying in magnet.After 5s,the superconducting magnet quenches due to the very fast current changing rate to generate the AC losses.The maximum hotspot temperature of superconducting magnet is about50K.It shows that the protection system can protect the superconducting magnet in very low hot-spot temperature.The magnet can be recovered to superconduc-ting state in about2.5h.It is expected to reduce cooling time through1.5W4K Sumitomo GM cryocooler.The temperature rise in the magnet is less than0.1K for oper-ating current to120A with40min,the current versus time is shown in Fig.4.The magnet has been stably operated in the Laboratory providing all kind of physical experiments. The superconducting magnet with the high temperature heat treatment device can generate the maximum tempera-ture of1200°C for material processing,such as metal and magnetism material etc.3.Superconducting magnet for gyrotron with homogenous regions of150mm and250mmBased on the requirements of the gyrotron,the super-conducting magnet has the following specifications:theTable1Design parameters for Nb3Sn and NbTiNb3Sn InnerNbTi Outer NbTiDiameter of wire(mm)0.9/1.05 1.0/1.050.65/0.69Short samplecharacteristics(4.2K)280A/10T670A/5T280A/5.6T 210A/12T400A/7T120A/8TInner diameter(mm)138232294 Outer diameter(mm)220290329 Height(mm)260288288 Total turn864069689744 Current density(A/mm2)133133308 Centerfield(T) 3.96 2.60 3.44 Inductance(H) 5.807.3020.2366Q.Wang et al./Cryogenics47(2007)364–379warm bore is over than/80mm,there are two homoge-nous regions with lengths of150mm and250mm,the homogeneity of magneticfield is0.25%and the magnetic field will be decayed1/6–1/7of its centerfield from the ori-ginal point to195mm,the centerfield is about4T[4].In order to design the superconducting magnet for the appli-cation of gyrotron,we take the trial-to-test method for the optimal design.In the design,it is necessary to select the safety factor for the magnet operated by the GM refrig-erator.The operating current safety factor in0.7and the maximum operating temperature of5.5K are selected for the magnet design.Fig.5shows the arrangement of super-conducting coils.There are four coils employed for the magnet with two homogenous regions,each region consists of three coils.The specifications for the superconducting magnet are listed in Table2.The coils can be divided into two layers.The internal coil referred as the main coil which is utilized to yield background magneticfield,can supply magneticfield of about4T along the axis of the magnet. The external layer is employed to compensate for homoge-neity in magneticfield.The external layer includes two sec-tions that are located at the top and bottom of the main coils,respectively,so that they are used in the compensa-tion for the250mm homogeneity region.The second part consists of a pair of compensation coils,one located in the middle and the other one located at the bottom of the main coil,which is employed for compensating the150mm homogeneity region.The same size superconducting wire is employed to wind the superconducting coils.The mag-neticfield homogeneity for the regions of150mm and 250mm is plotted in Fig.6.It shows that the magneticfield inhomogeneity j D B/B j is lower than0.2%.When the magnet system is designed,we should ensure that the requirements for magneticfield distribution and center magneticfield are satisfied.Under the condition of some unexpected quench in magnet,the protect devices should be used to protect the magnet.The total induc-tances including in the self-inductance and mutual induc-tance for250mm and150mm homogeneous regions are about11.5H and10.2H,respectively.The total storage energies of250mm and150mm homogeneous regions are about51kJ and45kJ for the center magneticfield of 4T,respectively.The energy will change into the heat energy that is released through a diode in the external cir-cuit during the quench of the magnet.An open loop circuit is strictly prohibited due to high voltage in coils.Based on the numerical analysis code[5],the process of quench occurred in the250mm homogeneity region is simulated. The protection circuit using a diode can convert about 51kJ energy stored into the heat energy which is dissipated in the normal zone resistance.The cooling capacity of the refrigerator is38W at40K at thefirst stage and1.5W at4.2K at the second stage,respectively.There is the vac-uum in the cryostat while the superconducting magnet is electrically connected with the external source and measur-ing system.There should be a part of refrigeration power to overcome the heat caused by the AC losses in current wires and coils.When we design the cryostat,the heat leak should be reduced as much as we can,otherwise it will lead to larger refrigeration power allowance.According to the requirements of the gyrotron,the con-duction-cooled superconducting magnet system has to sup-ply two uniform magneticfield regions.We need to consider the change in size of the warm bore in the cryostat along the axial direction.Fig.7shows the configuration of the cryostat and control system.It has an outer vacuum vessel on which is mounted the refrigerator which cools the40K thermal radiation shield and the magnetto Fig.5.Configuration of coil arranged for completed coil fabrication.Table2Specifications of superconducting magnetR1(cm)R2(cm)H(cm)Turn I(A)Safety factor Coil150mm homogeneous region6.48.624515,45894.32469.7219.1211.26 3.9129694.32447.1229.129.67216194.32424.153250mm homogeneous region6.48.624515,45894.15869.7319.1211.26 3.9129694.15847.0929.1211.26 3.9129694.15847.094Q.Wang et al./Cryogenics47(2007)364–3793674.0K.There is the vacuum in the cryostat while the super-conducting magnet is electrically connected with the exter-nal source and measuring system.There should be a part of refrigeration power to overcome the heat caused by the AC losses in current wires and coils.When we design the cryo-stat,the heat leak should be reduced as much as we can,otherwise it will lead to larger refrigeration power allow-ance.The dimensions of the cryostat which can meet the practical requirements are the following:external diameter 640mm,the height 770mm.There is an extensive warm bore at the bottom,which the diameter of extensive warm bore is about 290mm,and the depth is 75mm.The heat leak load of the first-class cold heat is about 18.6W,while the heat leak load of the second cold head is about 0.32W.Therefore,the superconducting magnet can stably operate.After the GM cryocooler is operating about 48h,the temperature of superconducting magnet is cooled to about 4K.Typical charging current with time is plotted in Fig.8.The maximum ramping rate is about 0.0506A/s,the charg-ing time is about 30min.During charging the supercon-ducting magnet,the maximum temperature rise is lower than 1K.The maximum temperature difference in the mag-net is lower than 0.01K.The quench characteristics are tested.During the quench of the magnet in operating cur-rent of 94A,the maximum temperature rise is lower than 30K.The test results show that the superconducting mag-net is reliably protected during quench,and the maximum hot-spot temperature can be pressed.The magnetic field inhomogeneity is about 0.19–0.21%for homogenous regions of 150mm and 250mm .4.Development of conduction-cooled high temperature superconducting magnet for separatorWe are carrying out a National High Technology Pro-gram in China to build a magnetic separator by using the conduction-cooled high temperature superconducting mag-net.The reciprocating magnetic separators are used in waste water treatment for special steel factory [6].The superconducting magnet should generate the magnetic field over 3T with the diameter of 120mm and operating tem-perature of 10–20K.The first HTS magnetic separator is experimental system.The HTS magnet has been designed with the length of 202.8mm and 120mm in inner diameter.The central mag-netic field is a nominal 3.2T with a design operating current of 120A.The specific parameters of the HTS magnet are listed in Table 3.The configuration for the magnet is illus-trated in Fig.9.The system operates in a vacuum and is conduction cooled via two-stage GM cryocooler with a nominal operating temperature of 20K.The HTS conduc-tor uses Bi-2223tape and coils were reinforced by a stainless steel tape.The HTS magnet is made of 3960m of Bi-2223superconducting tape.The HTS tape was tested in liquid nitrogen with critical current of 90A at self-magnetic field.The HTS current leads to be used in the magnetic separator were designed to improve shock resistance.The current leads were designed to operate with the warm end at about 40–50K and the cold end at 20K.The HTS magnet,cur-rent leads,and thermal shield are supported by G-10tubes and hung from the lid of the vacuum vessel.The cryocooler is mounted on the vessel lid and connected to the thermal shield top plate and the magnet cooling plate with flexible links to provide vibration isolation.The upper stage ofFig.7.Configuration for cryostat and control system.Fig.8.Charging current with respect to time.368Q.Wang et al./Cryogenics 47(2007)364–379the cryocooler cools the thermal shield and the heat pipe thermal intercepts.The heat pipe thermal intercepts com-bine high thermal conductivity with good electrical insula-tion and ensure that the upper end of the HTS portion of the current leads is adequately cooled.The lower stage of the cryocooler cools the HTS magnet and the bottom of the HTS current leads.The bottom of the leads is con-nected to the cooling plate by copper braid.The magnet is bolted to the cooling plate.The bottom plate of the HTS magnet and the magnet bore tube are made of copper and provide the conductive path into the windings for cooling.The magnet consists of individual double pancake windings stacked on the copper bore tube.Current lead mounting pads are provided to bolt the current leads to the magnet.For the turn-to-turn coil insulation,a coating of 0.01mm in thickness was applied to the Bi-2223tape as the tape was being wound into its double pancake coil.The double pancake coil was separated from its winding mandrel and spiral wrapped with glass insulation.The wrapped pancake coil was then placed on top of a copper sheet.The purpose of the copper sheet was to improve axial thermal conduction.The double pancake coil and its cop-per insert were then epoxy impregnated.After epoxy resin DW-3impregnation,the double pancake coils were stacked and spliced together on the inner diameter to form a con-tinuous double pancake coil.The double pancakes were then stacked in a precision fixture and subsequently spliced at the outer diameter using a copper transition piece.The HTS magnet is tested by conduction-cooled meth-ods.The cooling processing of HTS magnet is shown in Fig.10.The superconducting coil is cooled to its operating temperature takes about 24h.The operating characteristics of the coils were measured in operating temperature of 10K.In order to test the HTS magnet,various ramping rates for the HTS are studied.The typical charging current versus time with ramping rate of 1.6A/s is shown in Fig.11.The operating current of the coil was measured to be 120A and center field of 3.22T at the temperature of 10K.We have tested the magnet stability with the ramp-ing rates from 0.1A/s to 5.6A/s to the maximum operating current of 134A,there is no quench to occur in the HTS magnet during fast charging and discharging.In order to use the HTS magnetic separator to study the separating efficiency for industrial waste water treatment in iron steel factory,we employed the sample from the heat roll steel cooling waste-water from the Beijing special Iron-steel company.The operating magnetic field of 1T,1.5T and 2.0T is used to experiment research.We tested under magnetic field of 2T to deal with the waste-water from Beijing special iron-steel company with content in Fe 3O 4of 4.39mg/L.After treatment of waste-water,the content of Fe 3O 4is reduced from 4.39mg/L to 0.82mg/L.It shows the separating efficiency about 81.3%.Under magnetic field of 1.5T,the sample is separated two times.The content of FeB 3O 4is reduced from 4.39mg/L to 0.70mg/L.The separating efficiency is about 84.1%.5.Small-scale HTS magnet cooled by solid nitrogen for SMESSMES with the efficient energy storage capability,fast response and independent controllability over active andTable 3Model hts magnet parameters Design parameterValue Peak radius B r -field 1.72T Central B-field (B op ) 3.24T Operating current (I op )120A Operating temperature (T op )10KHTS conductorBi-2223PIT No.of double pancakes12Length of the HTS tape needed in a double pancake coils (m)200Total conductor length (km)$2.4Coil height (mm)119Coil inner diameter (mm)120.0Coil outer diameter (mm)207.1Fig.9.Configuration and assembled the HTS coils in cryostat.Q.Wang et al./Cryogenics 47(2007)364–379369reactive power has the potential to be applied to load lev-eling and power system control.SMES is particularly sui-ted in applications that rate high repetition rates (pulsating electrical loads).The critical current density of Bi-based superconducting tape is J C=104–105A/cm2at the operating temperature of20–30K and self-field.The applications of HTS tapes for the superconducting magnet have been employed in fabrication of SMES system.The design and fabrication of a conduction-cooled HTS magnet with solid nitrogen protection for a30kJ/30kW SMES are presented for the experimental research.This magnet sys-tem will be used to investigate fast discharging perfor-mances.The magnet is constructed with20double pancakes.Each pancake is wound with Bi-2223tape.The magnet has an outer diameter of250mm and heigh of 220mm.Cryogenic system for the magnet system is designed to cool the coils with a GM cryocooler together with the solid nitrogen.It is expected to operate the magnet system stand-alone.Totally4000m varnish coated super-conducting tapes are used to manufacture the magnet. The thickness of the varnish insulation is10l m.The criti-cal current of the superconducting tapes is90A at77K and selffield.The break-down voltage of the varnish coat-ing is guaranteed by the supplier as400V.Each of the20 piece superconducting tapes is tested using a non-contact detection device to examine the structure uniformity.Cryogenic system of the HTS superconducting magnet consists of a vertical cryostat,a solid nitrogen vessel,a liquid nitrogen vessel,a thermal shielding,current lead and a GM cryocooler.The thermal shielding with superin-sulation is connected to thefirst stage of the GM cryoco-oler inside the cryostat.The liquid nitrogen vessel is also connected to thefirst stage of the cryocooler.In this case, the thermal shielding can be anchored to the liquid nitro-gen temperature when the magnet system is operating at the stand-alone condition.The cryostat has an outer diam-eter of510mm and a height of810mm.The HTS magnet is located inside the solid nitrogen vessel.The solid nitro-gen vessel is made of stainless steel.It has an outer diame-ter of445mm and a height of276mm.Total volume is 26l.It is expected to contain18.5l liquid nitrogen for solidification.The liquid nitrogen vessel is on the top plate of the thermal shielding.Good thermal contact is guaran-teed by bolt fastening with the top plate.The diameter of the liquid nitrogen vessel is290mm and the height is 120mm.Total volume of the vessel is7.25l.It is expected to host5l liquid nitrogen to keep the thermal shielding at 77K when the magnet system is in stand-alone condition. The thermal shielding is made of copper material.Dimen-sions of the thermal shielding are designed with an outer diameter of490mm and a height of556mm.The inner shielding tube is set as82mm in diameter,which is installed between the warm bore and the solid nitrogen ves-sel.The solid nitrogen vessel is suspended by four FRP rod which can sustain the125kg cold weight.Thefinished solid nitrogen vessel together with the GM cryocooler is shown in Fig.12.The GM cryocooler has a cooling capacity of 1.5W at4.2K.The experiment test shows that the magnet system cooled from room temperature to10K takes about60h. The ramping rate for the superconducting magnet is about 25A/s to operating current144A.After the GM cryocoler stops working,the temperature rise of superconducting magnet from5.6K to40K takes about60h.6.Cryogenic test bed for characteristic study on high current HTS conductorThe cryogenic test bed for high-amperage critical cur-rent measurement with improved performance,without need of liquid helium logistics,large warm bore size super-conducting magnet without helium for more samples lengths and an improved and safe procedure for sample mounting and measurement is designed and will fabricated and tested on the basis of conduction-cooled superconduc-ting magnet technology[7].The development of a conduc-tion-cooled superconducting magnet technology generates the highfield to be operated without liquid helium and370Q.Wang et al./Cryogenics47(2007)364–379nitrogen.This technology provides access to high magnetic fields in applications or locations where the use of liquid helium is difficult or expensive.The conduction cooled superconducting magnet with requirements is listed as following:•warm bore size P 180mm;•central field B 0P 5T;•D B /B 61%(U 50·50mm);•D B /B 65%(U 100·100mm);•ramping rate:0.12T/min,0–5T (42min);•cool-down time <90h;and•operating mode with signal power supply.The operating temperature of superconducting magnet is defined at the 5.5K for the conduction-cooled supercon-ducting to take into account the temperature rise during charging.The thermal equilibrium of superconducting magnet and cryogenic system is analyzed to define ramping rate,operating current and margin of superconducting magnet for 1.5W cooling capacity at 4.2K.Two kinds of superconducting wires are used in the background mag-net design.One wire is chosen as a /1.0NbTi/Cu wire to wind the inner layers,another is a /0.65NbTi/Cu wire to wind the outer layers.The two compensating coil are to be wound with thinner wire.Critical currents of the two wires are characterized with 670A and 280A,respec-tively at 5T,4.2K liquid helium temperature.The detailed magnetic field calculation is shown in Fig.13.When theoperating current is set as 104.88A,the central magnetic field of the magnet is 5T,which is the requirement for HTS sample space.The maximum magnetic field for coil 1and coil 2are 5.5653T and 4.6T,respectively.For the two compensating coil,the maximum magnetic field is only 3.756T.The sample cryostat and sample holder should be designed and fabricated in a way to enable:easy mount-ing/change of the sample (one sample per day);no degra-dation of the sample due to mounting,cool-down and warm-up;reliable and reproducible measurements of the current-voltage.The sample of temperature range is 20–110K,and temperature measurement accuracy and stabil-ity are ±0.1K and T <±0.5K during the I –V-curve,Fig.12.Solid nitrogen vessel,liquid vessel and the GMcryocooler.Fig.13.magnetic field distribution for background magnet.Q.Wang et al./Cryogenics 47(2007)364–379371。