Before the discovery of atomic energy, humans only know of mechanical energy, such as the kinetic energy of the motor sport in the world; chemical energy, such as the burning of alcohol into carbon dioxide and water to release heat; has the power, when the current through the electric wire after emits heat and light, etc. . The release of energy, will not change the quality of the material, the only change in the form of energy.
For example, two identical cars are 5 tons, in a sports car is stationary, if the movement of the vehicle when a collision occurs with the vehicle stationary, suddenly stopped, although the loss of kinetic energy, but we found that become very hot in the car collided place. This is what causes it? Kinetic energy into heat energy point of the car crash into the metal. However, the release of atomic energy than chemical reactions nearly 5,000 times larger: This release form atomic fission of uranium is about 200 million electron volts (a unit of energy), and the chemical reaction of combustion of carbon emitted energy only 4.1 electron volts. Atomic how is it? After uranium nuclear fission fragments, but all these pieces add up to less than the quality of the nuclear fission of uranium before, then the quality of less gone out, because transformed into atomic energy. Einstein's equation E = mc2, ie: energy equals mass times the speed of light squared. Because of the speed of light is a very large number (c = 299792458m / s), so the quality will be converted into energy after a very great number, the energy released is ΔE = Δmc2. In the nuclear reaction process, the nucleus changes in the structure of the energy released, also known as nuclear energy, the late 1930s, scientists discovered that uranium nuclei bombarded with neutrons, an incident neutron fission of uranium into two to make a number of quality with moderate debris, while releasing large amounts of energy and two or three neutrons; two three neutrons can cause other uranium fission, producing more neutrons split more uranium nuclei. The thus formed a self-sustaining chain reaction can be instantaneously all the nuclear fission of uranium, a huge amount of energy is released. U-235 can be split in any particular movement energy neutrons slowest thermal neutron. Uranium-238 can be split fast neutron velocity of slow neutrons and thermal neutron capture not only the division. Commonly referred to as nuclear fission, mainly refers to uranium-235 fission. A release of uranium-235 fission nuclear fission energy is 200 million electron volts. This is a way to change the structure of the atomic nucleus, called fission reaction. Another way is called fusion reaction. As a deuteron and a tritium nucleus aggregated into one helium nucleus release of fusion energy as 17.6 million electron volts. Able to release the size of the same quality compared reactants, nuclear fission and fusion energy are able to chemical energy 250 times and 1000 times, 1 kg of uranium 235 is equivalent to 2500 tons of coal, equivalent to 1 kg of deuterium and tritium 10,000 tons of coal.
Atomic known as "nuclear." Changes when the nucleus of energy released. Such tremendous energy when heavy nuclear fission and nuclear fusion of light released. Radioisotope emits radiation applications in health care, food preservation is also an important aspect of the application of atomic energy.
Nuclear Power Plant
The use of uranium, plutonium, thorium nuclear fission in a nuclear reactor the release of heat, the water is heated to a high temperature and high pressure steam to drive a turbine generator to generate electricity power generation.
Consideration of ignorance in the beginning of this century, people of radium and other radioactive substances are also ignorant of the dangers. Manufacturing shop in New Jersey, USA, a watch, the women with a very sharp paint brush to paint containing radium needles coated surface of the watch. Some women with his lips straight bristles to keep paintbrushes sharp. They have to swallow a little less and less of radium is absorbed by the bones. A few years later, it was due to radium poisoning and death. This is typical because of the ignorance of the tragedy caused by radioactive substances. Some infected bones have been preserved in the laboratory for further research.
As human deepen the understanding of radioactivity and atomic energy, especially after the advent of the atomic bomb, a large number of scientists began to study the peaceful uses of atomic energy. It is now known that not only can be used to make atomic bomb, can also be used to develop production, improve people's lives, alleviate human suffering.
Atomic power is not a dream
The easiest way to think of it is the use of atomic energy to design a nuclear reactor, and then use the thermal power generated inside. However, with the much more expensive than nuclear power using traditional methods. Not primarily because of the fuel used is expensive, but because of the construction of nuclear power plant to be very safe, to prevent the escape of radiation. Only under technical conditions are ripe, the cost of nuclear power plant will be reduced.
From 1956 Britain's Queen Elizabeth II by pressing the switch button, the world's first large-scale nuclear power plant supply starts to 1965, the UK has 19 nuclear power plant, there are many power plants are designed to process. Many countries now have nuclear power plant.
When scientists talk about the first portable nuclear power plant, many people think they are dreaming. Today, some motorized nuclear power plant, or by car or by air to a location within 12 hours of use can be launched. And a pound of uranium is equivalent to 6,000 barrels of oil. For the desolate Arctic and Antarctic regions, under the conditions below freezing temperatures, light generation nuclear reactors seem to be the best way to solve the problem of electricity and heat supply. If the United States had a large box filled with 27 parts atomic power plants, each weighing about 15 tons, to a remote Wyoming mountains, to where to install up to become a medium-sized power plants for radar use.
In addition to power generation, smaller atomic reactors have other uses, the United States in 1955 launched the first nuclear submarine "Nautilus" is to use a piece of the same size and golf uranium driven. "Nautilus" in the first year tens of thousands of miles at sea, did not add any fuel.
Atomic reactors produce large amounts of heat, while also produce large amounts of neutron flux. There are some elements in the neutron flux bombardment can capture live one neutron, become radioactive elements. However, these elements are not commonly referred to as radioactive elements, they are only due to the absorption of a neutron radioactive, so people call them artificial radioactive elements. One more neutron, the mass of the atom has changed, people are also known as radioactive isotopes of these elements.
No matter what kind of radioactive elements, their performance is the same. It can continuously emit rays and particles. Radioisotope is relying on this performance was worth a hundred times.
Atomic Age "Sherlock Holmes"
Imagine a thief hurriedly fled from the scene. After his exit, rub out, but it is inevitable that a little paint almost imperceptible attached to his clothes, or maybe a little oil stains from the stolen car, or take away from the scene of crime strand of hair. Activation analysis using a radioactive atom can identify these tiny things, and let them pleaded guilty. Although different people's hair contains the same ingredients a little, but the number of all of its various components, but may vary.
Activation analysis, atomic energy in the industrial sector is the most interesting applications. When something upon radiation exposure, which each constituent element will become one isotope, but each isotope has its own unique way of radiation. With this method, scientists can identify the type of material in the object, and the precise amount of each ingredient.
Activation analysis has two advantages, one of which is available within minutes accurately identify substances. If using old methods in the past, it may take several days or even weeks.
Radioisotopes can be used as a screening tool to look for damage to the aircraft fuselage parts, and electrical systems coupled bad place. Some parts of the body is not easy to achieve, but the use of radioactive isotopes such as cesium-137 can be checked, and easy.
You can also protect the safety of radioactive reconnaissance machine operator. For example, hand-stamping machine operators available to protect radioactive cuffs, hand out when he did not come, because the relationship between the radiation machine will automatically stop.
Some cartons from the production line at the time, you can use radioisotopes to check if a cargo container loaded properly, when the container is provided through both sides of each isotope and radiation Geiger counter channels increases, a warning light will be lit up, or you can adjust the machine so that it can be excised timely poor packaging cartons.
Radioactivity in the industry as well as an application that tests the quality and effectiveness of the product. Soap and detergents for example. Bacterial smaller and smaller, you can not see them without a microscope. However, if the use of radioisotopes to cultivate bacteria, they have become radioactive, it can be easily measured with a Geiger counter. In order to check if the cleaning ability of various soaps and detergents, the radioactivity of bacteria on the clothes, and then each with a different soap and detergent, measuring residual bacteria can know every kind of soap and detergents good or bad.
Doctor's good "helper"
Everyone knows to treat cancer with radiation is very effective. American doctors had in a metal projectile, making it radioactive, and then use a special gun projectiles launched into entrenched inside the tumor.
After circumcision cancerous tumor, surgeons suture the wound with radioactive cobalt silk, not only can play the role of general stitched, radiation to kill cancer cells but also functional sense.
The use of radioactive carbon atoms traceable whereabouts in life processes. As rats eat radioactive carbon (carbon-14) of sugar, through the Geiger counter can detect sugar whereabouts. If you find a radioactive carbon atoms in the fatty rat, you can determine the sugar has been converted to fat.
Radioisotope sometimes help doctors make important judgments. A woman in the event of an accident crushed his arm, was lying in a hospital operating table awaiting surgery. However, the surgeon must be identified as soon as possible in her arms if there is enough blood circulating through in order to decide either to do amputations. Doctors put radioactive sodium salt form of radioactive braced ordinary table salt inside, injected into the blood vessels of this woman, and then use a Geiger counter to track. The results show that this arm still quite adequate blood circulation exists. So within a few seconds, this will enable doctors to determine radioisotope do not need amputation.
Radioisotopes in the diagnosis of cancer is also helpful. Harvard Medical School and Massachu_set_ts, many hospitals are using a "positron examination machine" to check the brain, rather than craniotomy. A small amount of radioactive arsenic is injected into the patient's vein, after a few hours, with a radioactive label arsenic became apparent in the Geiger counter, and shows where the maximum number of arsenic. Since cancer tissue than the normal absorption of many radioactive arsenic, in most cases, physicians can accurately determine the size and location of cancer. The breast cancer can be diagnosed using radioactive potassium, because radioactive potassium concentration and partial breast tumors than in other parts of many.
Obviously, you can not only radioactive deadly, but also make the patient freed from sickness.
Farmer's friend
With the development of biotechnology, radioisotopes in agriculture are also widely used.
Farmers across the United States each year for money on fertilizer to more than 10 million U.S. dollars. Radioisotopes can guide them how to use the investment to obtain greater benefits. For each crop, farmers can use radioisotopes to determine what and how much fertilizer application rate is the most appropriate and the best time and the best way to be able to determine fertilization. Previously it was believed that all plant nutrients are absorbed by the roots, but the use of radioactive isotopes as a tracer to prove that this is not the case. Fruit, tomatoes, potatoes and other plants leaves can also be quickly and effectively absorb fertilizer. According to this, the farmer is not only applied to the fertilizer land, sprayed on the leaves, such a plant fertilizer uptake increased more than about 10 times. You can also use radioisotopes improved varieties of plants.
Scientists have long known that the material exposed to radiation can mutate, and this variation can be passed on to the next generation. Currently, the use of improved plant varieties radioisotope great progress has been made. Radiation makes apples, pears, grapes and other mutations. With these experiments, humans can get arbitrary color, aroma and taste of fruits and vegetables. Further studies showed that scientists use radioactive scientific breeding, so that some plants can be grown in arid zones, some plants can grow in wetter areas. And in the near future, both in the alpine zone, or in poor soil areas, there will be suitable for growing crops.
In plant research scientists have successfully bred new varieties of barley, the variety of barley grain and straw yields are high. By radioactive seed peanut processing can yield per acre increased by 30%. Additionally, a need to adapt now bred seeds just one year and a half, if using traditional plant breeding methods, at least spent a decade and a considerable amount of money.
Radiation or a weapon to deal with pests. Male screwworm after cobalt irradiation, it can not give birth, female screwworm and loss of fertility in male screwworm mate the eggs will not develop adult. Agricultural scientists have been using this method to destroy a large number of pests.
The advent of the new animal fattening agents are harmful radiation can also be used to experiment. A new food for fattening pigs and chickens to pigs and chickens agent after eating, can slow down thyroid function, so that in the case of pigs and chickens eat the same, grow fast and fat. However, in pig muscles, if they contain ingredients such fatten agent? After people eat this meat, whether they would affect their health? In the chicken and scrambled eggs are also contained inside this fattening agents do? This is a worrying problem. However, the use of radioactive experimentally derived the answer is no. Farmers can safely use this agent to increase the weight of fattening pigs and chickens.
The use of animal drugs can slow the thyroid function of the human body does not cause any damage to this principle, scientists have become gentle disposition makes cows up and make more milk production.
We are entering the atomic age, the human crossroads. One way is to create the miracle of atomic energy for peaceful purposes is used in order to seek social progress. Another way is leading to the death and destruction of life on Earth, manufacture larger more terrible bomb. We believe that human beings would choose the former, not the latter. |