The “super-ring high-speed rail” advocated by the tech madman Musk has been recognized in the United States. Feasibility study is underway. The super ring high-speed rail utilizes low-vacuum pipelines and magnetic levitation technology, and the speed will be close to the aircraft’s speed of 1,000 kilometers per hour. This high-speed rail can not only It is also possible to excavate underground tunnels built on the surface. In China, this experiment is also under way. The Economic Half-Hour reporter saw a Chinese scientist working hard in a laboratory in Chengdu.
China announces high-temperature superconducting magnetic levitation technology
The world's first vacuum pipeline super high-speed magnetic levitation train annular experimental line platform built by Chengdu Southwest Jiaotong University is the first manned high-temperature superconducting magnetic levitation ring experimental line in China. The total length of the line is 45 meters. The design load is 300 kilograms and the maximum load can be reached. 1 ton, with a net suspended height of more than 20 mm, is the superconducting suspension system with the same international load capacity, the smallest cross section, and the smallest amount of permanent magnetic materials. It can perform 0-50 km/h actual dynamic operation experiments. Complex machinery and equipment, in the vacuum pipeline ideally, this technical innovation can increase the theoretical speed of the train to a higher speed of more than one thousand kilometers. In other words, the experimental equipment in front of this building will be The prototype of the future super high-speed rail that humanity can touch now.
Dr. Deng Zigang, Associate Professor of Southwestern Jiaotong University's State Key Laboratory of Traction Power Dr.: Many of the indicators are internationally leading. Our core stuff, its actual load capacity, is capable of suspending a ton of weight. The cross-sectional area of our track is now the smallest in the world. Its width is only 120 mm, its thickness is only 25 mm, and its permanent magnet material is particularly small.
The publication of this high-temperature superconducting magnetic levitation technology by Chinese scientists has attracted the attention of the IEEE, the largest association of electrical and electronic engineers in the world, and they reported the results of the Chinese scientific research in two full-page texts. The British BBC, the United States CNN, European public TV stations and other media rushed to the Southwest Jiaotong University to conduct field investigations and reports. The birth of this technology may not have caused much public concern, but in the eyes of many scientists in the world, China This time, people have done almost a revolutionary technological creation.
Deng Zigang: At the time, its title was called Super Pipeline. Then there were reviews. It felt that this subversive technology could have revolutionary implications for people's way of travel in the future, or space applications.
How can this “Super Pipeline”, which has been called a disruptive technology by many scientists in the world, be suspended on the track? The 37-year-old project leader Deng Zigang told reporters that for decades, Southwest Jiaotong University, a domestic research institute, and The experts of many manufacturing companies are constantly relaying R&D experiments to produce today's results.
Magnetic levitation technology was first proposed by Germans in the 1920s and is almost 100 years old. In the following decades, Germany was guided by permanent magnetic levitation, and Japan has maintained its leading position in low-temperature superconducting magnetic levitation; China has been in the past century. The catch-up began in the mid-eighties, but it is undoubtedly a huge challenge to catch up with the technological gap of six decades.
If we want to complete the research and manufacturing of magnetic levitation trains, we need to go through many thresholds in advance, such as where the high-temperature superconducting materials come from? How do special tracks be constructed? How do the car bodies design and how do they go from scratch? The challenge is whether Chinese scientists can succeed in research and development.
Superconductivity in high-temperature superconducting magnetic levitation refers to a superconducting material that has a zero-resistance effect, that is, no heat loss occurs when a current flows through a conductor, and a strong current can be formed in the wire without resistance, thereby generating Super magnetic field. Superconducting magnetic levitation is the use of superconductors to achieve magnetic susceptibility. And the so-called high temperature superconductivity, refers to the liquid nitrogen environment at minus 196 degrees Celsius, superconductivity has characteristics; low temperature superconductivity is at minus 269 The characteristics of superconductivity in the liquid helium environment in degrees Celsius.
Compared with low temperature superconductivity and room temperature superconductivity, high temperature superconductivity has one of the biggest characteristics: It has self-stability, in other words, after placing a high-temperature superconductor on a permanent magnet orbit, it can be suspended and suspended, regardless of motion. Still standing, it can be suspended; and in the permanent magnet track, the high temperature superconductor also provides a stable guiding force and levitation force, that is, does not shake up and down, like a nail, firmly on the top of the permanent magnet track.
Superconducting layer thickness is only one percent of hair
Can be suspended or suspended, it looks a bit like changing the magic. Where is the secret? The introduction of Deng Zigang, the first is the permanent magnet material laid on the track. In fact, high-performance permanent magnetic materials, have been developed abroad for many years, but These product technologies have been blocked for a long time in China, do not say buy, just want to visit will not work. The only way is for the Chinese to make their own. The magnetic levitation laboratory in Chengdu, but the magnetic levitation material, but a company in Hangzhou quietly R & D and production.
The development of high-performance permanent magnet materials, especially for permanent magnets on high-temperature superconducting magnetic levitation orbits, first requires the fusion of dozens of raw materials, including multiple rare earth materials, to be uniformly distributed.
Yongsong Dong, vice president of Hangzhou Permanent Magnet Group Co., Ltd., told reporters in the "economic half-hour" that this process is like kneading dough, but it is difficult, but it is critical to the performance of magnetic steel.
After more than a dozen kinds of raw materials are precisely arranged, it is necessary to use current to magnetize the magnet steel. This is also a relatively dangerous link. If the magnetization is not sufficiently charged, it may easily cause its performance to be unstable. Sometimes it cannot be controlled. Magnets can easily fly to the ceiling.
After repeated trials, high-performance permanent magnetic materials have been successfully developed, but then another problem arises: How do you stitch the permanent magnets together to form a magnetic suspension guide rail? Because the magnetic force between the permanent magnets is repulsive, a small magnetic force Blocks can generate more than 300 kilograms of thrust. If they are not careful, they can run away. Then, what methods can effectively solve the problem of splicing and combination?
Gu Shoudong, vice president of Hangzhou Permanent Magnet Group Co., Ltd.: It depends on a series of designed toolings. It is mechanically fixed little by little. A magnetic steel is fixed and a magnetic steel is installed.
Dr. Deng Zigang from Southwest Jiaotong University's State Key Laboratory of Traction Power: At that time, it was also a very thorough design in the previous period. After the fixtures were designed, the site continued to explore and continuously improve, and finally found a better way. With our last 84 permanent magnet tracks, the installation took only one day.
After solving the problems of the permanent magnet guide rail material, Deng Zigang's team began to face the test of the second difficult problem. This is the core high-temperature superconducting material for magnetic levitation trains in the world.
Deng Zigang: Our superconducting materials are installed in the four corners of our car. Inside this black cover plate. This superconducting material replaces the four wheels of our car. This superconducting material is in our liquid nitrogen. In a low-temperature environment, it can be suspended.
In the first 10 years of this century, there were only 3 second-generation HTS superconducting material suppliers in the world, 2 in the United States selling to the world at an expensive price, and another in Japan, but banned exports. By importing, China's development of high-temperature superconductor industry will be 'card neck'. After many searches, Deng Zigang's eyes locked in Shanghai Superconductor Technology Corporation.
Wu Xiang, deputy general manager of Superconducting Materials Division of Shanghai Superconducting Technology Co., Ltd.: Why do we do this? There is also a feeling of emotion. Because before we went to an international conference, the superconducting materials we reported were all made by others. When it comes to superconductivity in China, there is very little questioning. There is a feeling that no one in China has made this thing. Our idea is that, no matter what, we must make this out and we must fight for it. This tone.
In 2011, Shanghai Superconductor Technology Co., Ltd. was formally established and started research and development. The first difficulty they encountered was how to connect different coatings and superconducting tapes together. Superconducting tapes consist of several layers of different materials. For processing and painting together, the superconducting layer is located in the middle core layer, and is mainly divided into machine belts, isolation layers, buffer layers, etc. The seven and eight layers are added so many layers, and they mainly act as protection, buffering, and are equivalent to the middle. The layer of superconducting tape, wear a protective armor, so that the performance of the superconducting tape to maintain stability and consistency. However, these layers of raw materials are different, the thickness of the coating, needs to be very thin, very uniform. Big.
Zhao Yue, Special Researcher, Department of Electrical Engineering, Shanghai Jiaotong University, National Energy Smart Grid (Shanghai) R&D Center: It is a 50-micron-thick stainless steel strip coated with a superconducting thin film. What is the concept of 50 micron thick? It is our approximate hair thickness, but the most important superconducting layer that they play is only about 1% of the thickness of the hair.
Wu Xiang, deputy general manager of Superconducting Materials Division of Shanghai Superconducting Science and Technology Co., Ltd.: The superconducting layer is actually plainly white, and it is the most difficult to plate now, because its process is very special. We use laser deposition to deposit the coating.
But the most difficult is the technology that connects the superconducting tape together. Although the length of the superconducting tape has now reached the current kilometer-class length from the first hundred meters, it is limited by the existing technology and the world has not. Superconducting tapes without joints. When superconducting tapes have joints, they will have electrical resistance. How to reduce the electrical resistance to the lowest value is not only a problem for Chinese people, but also a problem faced by enterprises in various countries around the world.
Wu Xiang: Our company has developed a superconducting joint technology, its resistance can reach about two nano-ohms, and now everyone in the world can normally do about ten nano-ohms. Two nano-ohms are currently relatively low.
After more than three years of hard work, superconducting materials in the world's advanced level have finally been successfully developed in Shanghai, China.
Zhao Yue: Our same condition, compared with some similar products in the world, its performance and current carrying capacity increase by 25%. Under this condition, we are absolutely leading.
This kind of advanced superconducting material has broad application prospects, not only for magnetic levitation traffic, but also for superconducting cables, new energy car radio charging systems, and even defense military, such as the missile's new launch technology - cold launch.
Zhao Yue: The traditional missile method is the ignition launch. During the initial firing of the missile, it will generate a lot of heat and be detected by the enemy. This will take certain measures for the missile. If we use superconducting energy storage devices, In a short period of time, the huge energy can be quickly released. This weapon can be thrown into the air and reach a certain height and then ignite. The enemy can hardly find it. This is a very popular technology. Various developed countries are studying it.
The material and the track passed through the two difficulties. Deng Zigang in the Southwest Jiaotong University's laboratory began to face the final problem of the levitation test vehicle.
Like other material R & D models, the research and development of the magnetic levitation test car was transferred from Chengdu to the CRRC Tangshan locomotive company. How to make the car levitate and keep the magnetic levitation car safe and smooth, no matter whether it is a turn or a downhill slope? No noise? The researcher of CRRC Tangshan Locomotive Company took over the baton for R&D.
Wu Huichao, Ph.D., senior engineer, China National Vehicles, Tangshan Locomotive & Rolling Stock Co., Ltd.: Each of our bogies is equivalent to a row of concrete legs. When we turn, we can flexibly rotate each module when we go through corners. We are very flexible when we suspend the car through the entire small bend.
In 2014, the vacuum high-temperature superconducting magnetic levitation experimental line was successfully built in the Chengdu laboratory of Southwest Jiaotong University. Several generations of scholars from Southwest Jiaotong University have made unremitting efforts to create one after another miracle in the field of magnetic levitation. At the same time, they are engaged in scientific research. The theoretical contribution has also received great international and domestic responses. In 2016, Deng Zigang’s university teachers, Wang Jiasu and Wang Suyu, wrote their own lifelong research work and wrote it down for publication in Germany. At this time, a maglev was proposed by German scholars. Nearly a hundred years of technology, this is the first time that Chinese scholars have published the English-launched superconductor monograph in Germany, where magnetic levitation originated.
Dr. Deng Zigang, Ph.D., National Traction Power, State Key Laboratory of Southwest Jiaotong University: These two books embodies a process of high-temperature superconducting magnetic levitation, from leading to being chased to leading again.
The research achievements of Southwest Jiaotong University in the field of high-temperature superconducting magnetic levitation also strongly attracted foreign counterparts. Deng Zigang told reporters that several months later, in July 2018, several Brazilian scholars would come to study at the Southwestern Jiaotong University.
Zhang Weihua, chief professor of Southwestern Jiaotong University's national key laboratory for traction power: With the speed of 400 kilometers and 400 kilometers per hour this year, the completion of such a test platform, we can achieve the highest speed. Next we also do the speed of 1,500 kilometers per hour. Therefore, I think that we should go ahead in the world whether high-temperature superconducting magnetic levitation or vacuum piping.
At present, China, Germany, Japan, the United States, and Brazil are stepping up efforts to promote the practical application of superconducting magnetic levitation vehicles. The US Hyperloop one company built a 500 m long vacuum pipeline test line in the desert of Nevada, and achieved a 310 in 2017. The highest speed in km/h. In China, CRRC Qingdao Sifang Locomotive Co., Ltd. was officially launched in October 2016 to develop a high-speed maglev train with a speed of 600 kilometers per hour. In August 2017, China Aerospace Science and Industry Corporation announced that the fifth human species The “high-speed flying train” project for transportation has been researched and demonstrated. The maximum speed can reach 4,000 kilometers per hour. It is 10 times faster than the 350 kilometers per hour that the Beijing-Shanghai high-speed rail operates.
Half hour observation
At the most critical moment of technological development, our lens can record the hardships and boringness of the process. But as the President of Southwest Jiaotong University said, today’s era is an era of miracles. China’s high-speed rail has already taken a step into the world today. At the forefront of this, and the next generation of revolutionary technology research and development, Chinese scientists have not slackened in the slightest. Perhaps in the near future, when you and I are on a high-speed railway with a speed of 1000 kilometers per hour, we will recall the hard work of these scientists today. The process is such boring, but in the end it is a miracle made in China.
