Удачи, дорогие ученики
пятница, 15 мая 2015 г.
Вопрос
Сколько нужно времени, чтобы изучить английский?
Все зависит от вашей силы воли.
Вот, для разнообразия текст на английском:
Nuclear fusion reaction is a potentially infinite (in human capacity of grasping the infinity) source of energy. We know that nuclear fusion is possible, we see it going on in the sky every day and every night, when the weather is not cloudy – nuclear fusion is the source of light and other forms of energy of our Sun and other stars. We can reproduce nuclear fusion. Well, some of us can, you cannot do nuclear fusion in your kitchen or living room; it's not French fries or piña colada, not even Christmas turkey or Bloody Mary. We can even get energy out of it sometimes, destructive energy, unfortunately, in the form of explosions of very powerful thermonuclear bombs. But we cannot produce a sustainable and controllable nuclear fusion reaction so far.
The first man-made nuclear fusion reactions date back to 1933, when scientists accelerated two nuclei of deuterium (a heavy isotope of hydrogen with one proton and one neutron) and made them collide. Those nuclei formed an isotope of helium known as helium-3 – two protons and one neutron in its nucleus – and emitted a neutron and a small amount of energy. However, scientists immediately recognized that this energy could be huge if this reaction could be reproduced on massive scale. If it were possible to make one gram of those nuclei fuse, the output of energy would be equal to that of several tons of burned carbon fuels.
Quite soon scientists found out the conditions necessary for nuclear fusion reactions. You need to create hot plasma – gas, in which atoms move so fast that they lose all their electrons when colliding with each other, and there is a cloud consisting of nuclei and electrons moving independently. Then you have to heat the plasma even further, when the nuclei move so fast that when any two of them collide, they fuse in another nucleus, while emitting some particles and energy. Quite soon after that, in 1952, the first thermonuclear bomb was created and tested. Basically, a thermonuclear bomb is a capsule with deuterium and tritium (the latter is the heaviest isotope of hydrogen, with one proton and two neutrons). This capsule is put inside a nuclear fission bomb (or very close to it) of relatively low power. When the nuclear fission bomb explodes, it creates conditions for nuclear fusion, and the main and much more powerful explosion follows in nanoseconds.
The first attempts to create a sustainable and controllable nuclear fusion reaction were made in 1958. The idea of scientist was to put atoms of deuterium and tritium into a confined space and to heat them up with magnetic field to the point at which they would become hot plasma, all nuclei separated from electrons, and nuclei colliding at such speed that some of them could fuse. Also it was important to keep that plasma from contacting with the walls of the confined space. When this contact happens, plasma cools down immediately, and there are no conditions for nuclear fusion anymore. For technical reasons, the confined space was made in the form of a torus. The fusion was achieved, but the output of the energy was much smaller than the input, and the fusion reaction lasted microseconds. At least, it was controlled, and no explosions followed.
Then many years of development followed. Several torus installations were built. Other methods of creation of high temperature plasma were tested, including particle accelerators and lasers. But not a single installation has been able to produce more energy than was used for initiating the nuclear fusion reaction.
The project ITER (originally an acronym of International Thermonuclear Experimental Reactor and Latin for "the way" or "the road") began in 1985 as a Reagan-Gorbachev initiative of international cooperation on developing something very important and useful for the whole humankind. The initial participants were the USA, the USSR, Japan and the countries that later formed the EU. More countries, like Canada, China, South Korea, India and some others joined in.
After many years of preparation and designing the actual construction of a new torus reactor began. After many discussions about the location of the new reactor (many countries wanted to have it on their territory) the place for the reactor was chosen at Cadarache, a research center in South France.
The reactor is being built on a mountain. The top of the mountain had to be removed, and a big pit, 20 meters deep, was made in it. As there is some seismic activity in French Alps, all measures for protecting the future reactor from earthquakes were taken. The reactor needs very powerful magnets in order to keep plasma from contact with the walls of the torus. These magnets are to be superconductive. Such magnets are not new, but no one has ever built before so big and powerful superconductive magnets. It is not possible to build them at a plant and then deliver them to the construction site. They have to be built in situ. Also the magnets need a very powerful cooling system. Superconductivity occurs at very low temperature, something like 3 kelvins (minus 270 degrees Celsius). You have to cool those magnets with liquid helium. And, in order to protect this cooling system from outside heat, another cooling system based on liquid nitrogen is being created, which produces temperature of 80 kelvins (minus 193 degrees Celsius). The temperature of the plasma is to be several million kelvins. Extreme cold and extreme heat will be very close to each other in that reactor.
Scientists and engineers working on this project make many things which humankind has never made before. This project can create a useful spin-off in other industries even before it achieves its goals.
The construction phase is expected to be finished in 2019. Then testing, preparation and cooling down of huge magnets will require another year, therefore the first attempts to create and hold hot plasma in the reactor are expected in 2020. Attempts to launch deuterium-tritium fusion are expected no earlier than in 2027. Scientists hope to achieve output of energy that will exceed input in a controllable and sustainable fusion reaction lasting 1000 seconds or more. If this happens, it will be a very important breakthrough for the whole humankind. The previous records were from microseconds to 5 seconds.
This text was inspired by the information presented in the "Discovery" BBC radio program.
Все зависит от вашей силы воли.
Вот, для разнообразия текст на английском:
Nuclear fusion reaction is a potentially infinite (in human capacity of grasping the infinity) source of energy. We know that nuclear fusion is possible, we see it going on in the sky every day and every night, when the weather is not cloudy – nuclear fusion is the source of light and other forms of energy of our Sun and other stars. We can reproduce nuclear fusion. Well, some of us can, you cannot do nuclear fusion in your kitchen or living room; it's not French fries or piña colada, not even Christmas turkey or Bloody Mary. We can even get energy out of it sometimes, destructive energy, unfortunately, in the form of explosions of very powerful thermonuclear bombs. But we cannot produce a sustainable and controllable nuclear fusion reaction so far.
The first man-made nuclear fusion reactions date back to 1933, when scientists accelerated two nuclei of deuterium (a heavy isotope of hydrogen with one proton and one neutron) and made them collide. Those nuclei formed an isotope of helium known as helium-3 – two protons and one neutron in its nucleus – and emitted a neutron and a small amount of energy. However, scientists immediately recognized that this energy could be huge if this reaction could be reproduced on massive scale. If it were possible to make one gram of those nuclei fuse, the output of energy would be equal to that of several tons of burned carbon fuels.
Quite soon scientists found out the conditions necessary for nuclear fusion reactions. You need to create hot plasma – gas, in which atoms move so fast that they lose all their electrons when colliding with each other, and there is a cloud consisting of nuclei and electrons moving independently. Then you have to heat the plasma even further, when the nuclei move so fast that when any two of them collide, they fuse in another nucleus, while emitting some particles and energy. Quite soon after that, in 1952, the first thermonuclear bomb was created and tested. Basically, a thermonuclear bomb is a capsule with deuterium and tritium (the latter is the heaviest isotope of hydrogen, with one proton and two neutrons). This capsule is put inside a nuclear fission bomb (or very close to it) of relatively low power. When the nuclear fission bomb explodes, it creates conditions for nuclear fusion, and the main and much more powerful explosion follows in nanoseconds.
The first attempts to create a sustainable and controllable nuclear fusion reaction were made in 1958. The idea of scientist was to put atoms of deuterium and tritium into a confined space and to heat them up with magnetic field to the point at which they would become hot plasma, all nuclei separated from electrons, and nuclei colliding at such speed that some of them could fuse. Also it was important to keep that plasma from contacting with the walls of the confined space. When this contact happens, plasma cools down immediately, and there are no conditions for nuclear fusion anymore. For technical reasons, the confined space was made in the form of a torus. The fusion was achieved, but the output of the energy was much smaller than the input, and the fusion reaction lasted microseconds. At least, it was controlled, and no explosions followed.
Then many years of development followed. Several torus installations were built. Other methods of creation of high temperature plasma were tested, including particle accelerators and lasers. But not a single installation has been able to produce more energy than was used for initiating the nuclear fusion reaction.
The project ITER (originally an acronym of International Thermonuclear Experimental Reactor and Latin for "the way" or "the road") began in 1985 as a Reagan-Gorbachev initiative of international cooperation on developing something very important and useful for the whole humankind. The initial participants were the USA, the USSR, Japan and the countries that later formed the EU. More countries, like Canada, China, South Korea, India and some others joined in.
After many years of preparation and designing the actual construction of a new torus reactor began. After many discussions about the location of the new reactor (many countries wanted to have it on their territory) the place for the reactor was chosen at Cadarache, a research center in South France.
The reactor is being built on a mountain. The top of the mountain had to be removed, and a big pit, 20 meters deep, was made in it. As there is some seismic activity in French Alps, all measures for protecting the future reactor from earthquakes were taken. The reactor needs very powerful magnets in order to keep plasma from contact with the walls of the torus. These magnets are to be superconductive. Such magnets are not new, but no one has ever built before so big and powerful superconductive magnets. It is not possible to build them at a plant and then deliver them to the construction site. They have to be built in situ. Also the magnets need a very powerful cooling system. Superconductivity occurs at very low temperature, something like 3 kelvins (minus 270 degrees Celsius). You have to cool those magnets with liquid helium. And, in order to protect this cooling system from outside heat, another cooling system based on liquid nitrogen is being created, which produces temperature of 80 kelvins (minus 193 degrees Celsius). The temperature of the plasma is to be several million kelvins. Extreme cold and extreme heat will be very close to each other in that reactor.
Scientists and engineers working on this project make many things which humankind has never made before. This project can create a useful spin-off in other industries even before it achieves its goals.
The construction phase is expected to be finished in 2019. Then testing, preparation and cooling down of huge magnets will require another year, therefore the first attempts to create and hold hot plasma in the reactor are expected in 2020. Attempts to launch deuterium-tritium fusion are expected no earlier than in 2027. Scientists hope to achieve output of energy that will exceed input in a controllable and sustainable fusion reaction lasting 1000 seconds or more. If this happens, it will be a very important breakthrough for the whole humankind. The previous records were from microseconds to 5 seconds.
This text was inspired by the information presented in the "Discovery" BBC radio program.
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