X-ray is an electromagnetic wave with short wave length and high energy, which is produced by the deceleration of high-energy electrons or the orbital electron transition in the inner layer of atoms.
Its wavelength is between optical ultraviolet light and K wave of Y-ray (see Figure 7-1), ranging from -6 power nm of 10 to l0nm. In the traditional X-ray spectrum analysis, the wavelength range involved is from 0.0 1 nm (UK.
Line) to 2 nanometers (FK. Line).
X-rays can be produced by an X-ray tube. The inside of the X-ray tube is evacuated, and it has a cathode (filament), an anode (target) and an exit window, and a DC high voltage of several thousand volts is applied between the anode and the cathode.
Electrons heated in the cathode circuit are attracted by the high voltage of the anode and are emitted to the anode at a very high speed. At this time, X-rays are emitted from the anode and emitted to the outside of the tube through an extremely thin beryllium window.
2. What are the tips for preventing radiation life?
First: about 30cm away from the monitor. This is to protect eyes and skin.
Second: the first thing to do when sitting in front of the computer every day is to wipe the screen. Dust on the screen tends to accumulate radiation particles. It's bad for the body and skin.
Third: it is a matter of pure face. It is necessary to apply cream every day. Be sure to clean your face systematically and comprehensively after leaving the computer. But I am lazy. I just wash my face at best. I will take good care of it before going to bed at night.
Fourth: You can put some green plants, cactus and aloe in front of the computer. Let's not talk about whether it will absorb radiation particles. Seeing green after fatigue has a relaxing effect on eyes and brain nerves.
Fifth: eat more green and natural food. Drink more water. Good health, strong natural resistance, the human body has its own immune system.
Sixth: The keyboard radiates the most. If you don't need to be close to the computer, try to stay away from the keyboard.
Seventh: You left the radiation master. . . Ha ha. . When something happens, don't forget to stretch, get up and walk, which is good for bones and nerves and prevents any problems in arteries and veins. This is medical knowledge. I just took it with me. Anyway, doing these actions is beneficial and harmless.
Eighth:
. . . . . To be continued.
Distribute common sense
The harm of radiation is as follows: With the development of wireless communication technology, more and more people use mobile phones, and the related health problems brought by mobile phones are also getting more and more attention.
How harmful the radiation of mobile phones is to human body, and how to minimize the harm has become the most concerned issue for mobile phone users. When people use mobile phones, they will send radio waves to the transmitting base station, and the human body will absorb these radio waves more or less. These radio waves are the radiation of mobile phones.
Generally speaking, mobile phones radiate less when they are in standby and more when they are talking. When the mobile phone number is dialed but not connected, the radiation is the largest, and the radiation amount is about three times that of standby. These radiations may change human tissues and adversely affect human health.
1, don't put it near the head. Cell phone radiation is harmful to people's heads. It will cause dysfunction of people's central nervous system, causing headaches, dizziness, insomnia, dreaminess, hair loss and other symptoms, and some people will feel * * * on their faces.
Therefore, when using mobile phones, it is recommended that you use headphones, because using headphones can effectively reduce the impact of mobile phone radiation. If you don't have headphones, you'd better put your mobile phone away from your body and talk into your ear.
In addition, try not to chat with your mobile phone, and be careful not to put your mobile phone on the pillow when you sleep. There are many examples of brain cancer caused by long-term use of mobile phones at home and abroad.
2. Many girls like to hang their mobile phones on their chests, but research shows that hanging them on their chests will have a certain impact on the heart and endocrine system, and electromagnetic radiation will also affect endocrine function, leading to menstrual disorders in women. Even in the standby state with less radiation, the electromagnetic wave radiation around the mobile phone will cause harm to the human body.
People with cardiac insufficiency and arrhythmia should pay special attention not to hang their mobile phones on their chests. Mobile phones are generally equipped with shielding equipment, which can reduce the harm of radiation to human body, and shielding equipment containing heavy metals such as aluminum and lead has better protection effect.
However, for the sake of beauty, girls often choose compact mobile phones, and the protection function of such mobile phones may not be perfect enough. Therefore, female friends had better not hang their mobile phones on their chests. 3. Male friends rarely hang their mobile phones on their chests, but they generally don't put them on their waists or pockets.
This is not good either. The biggest headache for men is that mobile phone radiation may affect men's reproductive function ~ ~ ~ It is recommended to keep the mobile phone as far away from the waist and abdomen as possible, and not to hang it on the waist or put it in the coat pocket. When in the office, at home or in the car, it's best to put your mobile phone aside.
When you go out, you can put your mobile phone in your purse and stay away from your body.
4. Radiation safety knowledge and radiation protection knowledge are more detailed.
Large power station.
In the far field. In order to avoid exposing yourself to the danger of over-dose radiation, radiation dosimetry studies radiation dose and its measurement.
Radiation protection standard is the basis of implementing radiation protection. The focus of distance protection is to maximize the distance between human body and radiation source, radiation safety, radiation pollution to the environment and so on. The electromagnetic field intensity of near-field radiation is relatively large, so.
● Keep a safe distance when using all kinds of electrical appliances. There are also many phenomena of excessive radioactivity. The electric field is much stronger than the magnetic field. Electromagnetic protection should focus on the near field, satellite earth communication stations, subway trains and electric trains, as well as most household appliances, which can produce various forms. ● The electromagnetic radiation released by the mobile phone at the moment of power-on is the largest.
Don't put the household appliances too concentrated. 1 the near field and its characteristics are centered on the field source, and the area within a wavelength range is usually called near field or induced field. The near field usually has the following characteristics: in the near field, there is no definite proportional relationship between the electric field intensity and the magnetic field intensity.
Namely: e? The principle is as follows: pregnant women and children should stay away from the microwave oven as much as possible. The far field is a weak field, so listen carefully after receiving the mobile phone: the principle of time protection is that the cumulative dose of radiation received by people in the radiation field is proportional to time, so.
A staff member surnamed Song of the Pollution Management Office of the Municipal Environmental Protection Bureau said that radiation sources hidden in our homes are also everywhere. At present, some natural decorative stones used in household decoration have radioactive pollution, while coal ash bricks made of industrial waste residue are perpendicular to the propagation direction of electromagnetic waves.
The intensity of electromagnetic field in the near field is much greater than that in the far field. Under the condition of constant irradiation rate, shortening the irradiation time can reduce the accepted dose, or work at a certain distance, so that the radiation dose received by people is lower than the maximum allowable dose, or people work in a limited time. Protect the near field of electromagnetic radiation, which is the enemy of maternal and infant health, and strengthen the body's ability to resist electromagnetic radiation. Don't hang your mobile phone on your chest when pregnant women answer the phone. Try not to use electric blankets when it is cold, especially for expectant mothers who cover them. The electromagnetic wave of light bulb is lower than that of fluorescent lamp, so fluorescent lamp can be used less.
5. Conditional pregnant women can wear radiation protection suits when they go to work, and they can take a shower and change clothes after work; Use computer, TV radiation screen, etc. 6. Microwave ovens and induction cookers are electrical appliances in the electromagnetic radiation market at home, and pregnant women should try to avoid using them.
The coil and motor of the refrigerator are behind the refrigerator, so when you open the refrigerator door to get something, don't use it for too long and keep a safe distance. 7. There is radiation in general wires at home. In modern families, the general fixed wires are "hidden wires", which is not a big problem, but if very dense wiring boards or plugs are placed at the bedside or in the most frequent places, it may affect health.
Therefore, the bedside should not be equipped with electrical appliances or plugs. Radiation protection in working environment 1. X-ray radiation of computer screen: This radiation can usually be blocked by only one piece of glass fiber. If there is no glass fiber, pregnant women should try to keep a distance of more than 30 cm from the computer screen.
Radiation from the electric coil on the back of the computer: This radiation is harmful, but most people don't work behind the computer. If there is a mother-to-be working in the computer room, pay attention to it and try to avoid doing homework behind the computer.
2. The radiation of mobile phone is also tiny. Although its efficacy is not as strong as that of microwave oven, it will also cause harm to human body. Therefore, it is best for expectant mothers to reduce the chances of using mobile phones and try to avoid hanging them around their waists.
At present, there is still a debate about "CDMA mobile phone or GSM mobile phone, which is more radiation." Therefore, no matter what mobile phone the expectant mother uses, she should be as careful as possible. It is suggested that mothers use hands-free when using mobile phones, or wear radiation-proof headphones.
3. Copier When the expectant mother uses the copier, the body is 30 cm away from the machine as a safe distance. At present, the newer copiers on the market all install the radiation parts on the chassis, which does little harm to the body.
The medical environment is protected from the influence of X-ray radiation on the fetus, which is more likely to lead to embryonic disability, fetal malformation, brain dysplasia and an increase in the probability of childhood cancer. But usually in the early stage of pregnancy, exposure to X-rays is more likely to cause major injuries, and the closer to the expected date of delivery, the smaller the impact.
According to the staff of the radiology department of Jilin City Hospital, if a pregnant woman receives 5 thunder X-rays, it is equivalent to taking 20 abdominal X-rays. Doctors suggest that unless there is an emergency, you should choose to take X-rays within 10 days after menstruation begins, so you don't have to worry about taking X-rays after pregnancy.
So, what about pregnant women who have already taken X-rays? It is understood that pregnant women who are unknowingly exposed to X-ray radiation should try their best to keep filming records so that doctors can help you judge the safety of the fetus. Generally, during pregnancy, if you just take an abdominal X-ray, the exposure will be about 0.5 rays, and the impact on the fetus is not enough to require pregnant women to have an abortion; However, only a small amount of radiation, such as chest X-rays or dental X-rays, has even less impact on the fetus.
Therefore, as long as it is not aimed at high-dose X-ray radiation in or near the abdomen, expectant mothers need not worry too much. Radiation granite marble steps that may be encountered when going out: Many people will regard the marble steps in front of department stores as reclining chairs, but they don't know that this granite marble is a high radiation material.
If a closed room is decorated with such materials, it is likely to lead to nasopharyngeal carcinoma or lung cancer. Substations and high-voltage electricity: No matter where you choose to live or play, it is best to stay away from substations and high-voltage electricity, especially nuclear power plants.
Airplane: Flight attendants are most likely to miscarry or have an impact on the fetus in the early pregnancy due to long-term exposure to cosmic waves. Studies have pointed out that long-term flight during pregnancy should not exceed 100 hours, so as not to affect the health of the fetus.
The experience of users using "radiation protection suits" is different. Now it has entered the fourth generation. For example, the radiation of PHS widely used by citizens is about 30-50db, while the radiation of mobile phones is above 250db. Now the fourth generation of radiation protection suits are different in style, but there is one thing.
5. Some common sense about mobile phone radiation, don't get into the water.
1. Although the phone is turned off, the functions such as clock, incoming call information and alarm clock are still running.
So there will still be some radiation, which will still have a certain impact on the human body. The radiation is strongest in the first five seconds when the mobile phone is turned on, because the radio reception is still unstable at that time. It is recommended to put your mobile phone in a drawer when you sleep, which can effectively isolate radiation. Don't put it on the pillow.
Second, if you carry your mobile phone with you, you'd better hold it in your hand or put it in your backpack. If placed near the heart, it will affect the heart and endocrine system for a long time.
Putting it on the waist will have a bad effect on the liver, and putting it in the trouser pocket will kill sperm and affect men's health. So it's best to put that bag inside, and the radiation of the mobile phone should also be prevented.
Third, the pen is hungry ... someone answered it upstairs ... I don't understand this either. I hope the above can give you some help.
6. Knowledge about radiation
Radiation is a kind of energy that propagates in the form of energy beams such as waves or particles. In fact, radiation is not always so terrible. Radioactive radiation can be divided into natural radiation and artificial radiation. There are three main sources of natural radiation: cosmic rays, earth radiation sources and radioactive substances in the body. Artificial radiation sources include radiation sources used for radiological diagnosis and radiotherapy, radioactive drugs, radioactive waste, dust falling from the explosion of nuclear weapons and radiation generated by nuclear reactors and accelerators.
In daily life, radioactivity always exists, such as the use of electrical products, X-ray inspection and so on. Are all man-made radiation that people will come into contact with in modern society. When eating food, the human body will receive about 0.02 millisieverts of radiation every year, while smoking 20 cigarettes every day will receive 0.038~0.075 millisieverts of radiation every year. It can be said that human beings will be exposed to a small amount of radioactive radiation in their life.
■ tips
The recent explosion of nuclear power plants in Japan has aroused the concern of ordinary people about "nuclear radiation". In fact, people will also be exposed to a small amount of radioactive radiation in their daily lives, which will generally not cause harm to the human body. Today, this newspaper introduces you to the knowledge about radioactive radiation.
1
Radiation in life:
The total radiation dose of air, food and water consumed by people every year is about 0.25 millisieverts.
Wearing a night watch has 0.02 millisieverts a year.
Traveling 2000 kilometers by air is about 0.0 1 millisievert.
An X-ray examination is 0. 1 millisieverts.
Please note the following points:
Wearing metal-framed glasses for a long time may cause radiation damage to the brain and around the eyes.
Try to reduce the time of using small household appliances such as hair dryer, electric shaver and vacuum cleaner every time, and try to stay away from your body when switching power supply.
People who use computers for a long time should put a glass of water in a plastic cup or glass and put it next to the computer to reduce radiation.
Because the mobile phone calls at the moment of connection and charging, it releases the largest electromagnetic radiation, so it is best to answer the phone after the phone rings for one or two seconds.
It is not appropriate to answer the phone when the mobile phone is charging.
How harmful is it? Trace radiation does not affect health.
Trace radiation will not cause harm to human body, because the human body itself has the ability to repair mild radiation damage. Only high radiation exceeding the dose will cause pathological changes in human organs.
Millisievert is one of the basic units for measuring radiation dose, and 1 millisievert is equal to 1000 microsievert. People who are not engaged in radioactive work are exposed to natural radiation of 1000~2000 microsieverts every year. Radiation below 100 microsieverts has no effect on human body. 2000 millisieverts is the watershed to determine the damage degree, beyond which radiation will cause irreversible damage. 4000 millisieverts of radiation at a time will kill you. The radiation in life basically belongs to trace radiation and belongs to the scope of human body repair.
2
How to avoid radiation? Answer the phone in a second or two.
Although the trace radiation in life does little harm to the human body, in line with the life philosophy of "less radiation, more health", we should try our best to plan ahead and reduce the possible negative impact of life radiation. In particular, "mobile phone owners" and "computer owners" receive more radiation doses than ordinary people, which may cause cumulative damage to physical function. We can do a good job of "radiation protection" in our daily life of eating, wearing and living.
Eating: Modern medicine has confirmed that eating nutritious food through diet can effectively reduce or even resist the harm of radiation to human body. Black sesame, amaranth, green tea, lycopene, spirulina food, pollen food and ginkgo products are all considered as radiation-proof foods. White-collar workers who often face computers should pay attention to the intake of such foods in order to resist radioactive substances through a healthy diet.
Wear: Research shows that metal spectacle frames can also significantly enhance the electromagnetic field and increase the radiation absorption rate of users. After a long time, the radiation of electromagnetic field may spread around the brain and eyes through glasses with metal frames, causing some damage; Pregnant women should minimize the use of computers, mobile phones, microwave ovens and other high-frequency radiation appliances, and wear reliable radiation protection clothing for pregnant women when necessary.
Usage: For small household appliances with close contact with human body and high frequency of use, such as hair dryer, electric shaver and vacuum cleaner, experts suggest to minimize the use time and stay away from the body as far as possible when switching power supply; Household appliances should not be concentrated or often used together, especially televisions, computers and refrigerators, which should not be concentrated in the bedroom to avoid long-term exposure to excessive radiation; People who use computers for a long time can put a glass of water in a plastic cup or glass and put it next to the computer. Because the mobile phone calls at the moment of connection and charging, it releases the largest electromagnetic radiation, so it is best to answer the phone after the phone rings for one or two seconds, and it is not appropriate to answer the phone when the phone is charging.
7. Questions and answers about nuclear knowledge and radiation protection knowledge
1. What is nuclear radiation? The energy emitted by radioactive substances in the form of waves or particles is called nuclear radiation.
2. What are the main rays of radiation? What is its essence? What's the impact? Radiation is mainly α, β and γ rays: α rays are helium nuclei, which can be blocked by a piece of paper, but they are harmful if inhaled into the body; β -ray is an electron flow, which has obvious burning sensation after irradiating the skin. Because of their small penetrating power, these two kinds of rays have a close influence distance, and as long as the radiation source does not enter the body, the influence will not be too great; Gamma rays have strong penetrating power and are short-wavelength electromagnetic waves.
Gamma radiation, similar to X-rays, can penetrate human bodies and buildings, and the harm is far away. There are many radioactive substances in the universe and nature, but the harm is not too great. Only radioactive materials leaked from nuclear explosions or nuclear power plant accidents will cause large-scale casualties.
Electromagnetic wave is a very common radiation, and its influence on human body is mainly determined by power (related to field strength) and frequency. Radio waves used for communication are low-frequency electromagnetic waves. If arranged from low frequency to high frequency (from long wavelength to short wavelength), electromagnetic waves can be divided into: long wave, medium wave, short wave, ultrashort wave, microwave, far infrared ray, infrared ray, visible light, ultraviolet ray, X ray, gamma ray and cosmic ray.
Taking visible light as the boundary, electromagnetic waves with frequencies lower than (longer than) visible light mainly have thermal effects on human body, while rays with frequencies higher than visible light mainly have chemical effects on human body. 3. What are the sources of artificial radiation? Artificial radiation sources include radiation sources used for radiological diagnosis and radiotherapy, radioactive drugs, radioactive waste, dust generated by nuclear weapon explosion and radiation generated by nuclear reactors and accelerators.
Facing the threat of nuclear radiation, how should we protect ourselves and our families? First, enter the room, close the doors and windows to prevent radioactive substances from floating in, and then take anti-radiation drugs such as potassium iodide. If it is necessary to go out, in order to prevent radioactive dust from being inhaled into the body and contaminated on the skin, people in polluted areas should wear gas masks or masks as soon as possible, tie up pants, cuffs and necklines, and cover exposed skin with raincoats and plastic sheets. They shouldn't eat in the open air or sit on the ground. If you don't touch contaminated objects, avoid raising dust. When clothes are contaminated by radioactive substances, you can use a broom or branches to stand in the direction of headwind or crosswind, sweep from top to bottom, from outside to inside, or rinse with water. Adding a small amount of detergent can improve the elimination effect. Of course, if conditions permit, you can give the changed clothes to rescuers and throw them away completely.
5. How to treat after receiving nuclear radiation? At present, there is no drug that can completely protect the human body from radiation. The best way to prevent the threat of nuclear radiation is to keep yourself in a relatively isolated environment to avoid radiation damage caused by nuclear pollutants from damaging the hematopoietic and immune systems of the human body. If you have received radiation injury, the rehabilitation method can refer to the course of treatment after tumor radiotherapy. 6. What radiation-resistant foods are there in daily life? According to the traditional Chinese medicine theory of black sesame, black enters the kidney, "the kidney dominates the bone and ascends the marrow to the brain". All kinds of radiation hazards mainly affect the brain and bone marrow of people and damage the immune system.
Eating more foods that tonify the kidney can enhance the body's cellular immunity and humoral immunity and effectively protect human health. Amaranth Amaranth can resist radiation, mutation and oxidation, which is related to its selenium content.
Selenium is an important trace element, which can enhance immune function and protect human health. Eating amaranth rich in selenium often can improve the anti-radiation ability of human body.
Tea polyphenols in green tea are anti-radiation substances, which can reduce the adverse effects of various radiation on human body. Tea also contains lipopolysaccharide, which can improve human hematopoietic function and increase platelets and white blood cells.
Vegetables and Fruits Eat more fresh fruits and vegetables, and you can get a lot of vitamins A, B, C, E ... These vitamin-rich foods can reduce the subtle influence of electromagnetic radiation on the human body and avoid nervous system disorders.
Spicy food Chili and other spicy foods are common seasonings and natural food with radiation resistance. Eating pepper can not only mobilize the whole immune system, spices such as pepper, black pepper, curry and ginger, but also protect the DNA of cells from radiation damage.
Therefore, eating spicy food often will make you healthy.
8. Nuclear radiation knowledge
Nuclear radiation means that radioactive nuclei (such as uranium and plutonium) emit "α", "β" or "γ" rays.
Nuclear leakage affects people's general situation. In nuclear radiation, it is also called radioactive material. Radioactive substances can be inhaled through breathing, absorbed into the body through skin wounds and digestive tract, causing internal radiation, and gamma radiation can penetrate a certain distance and be absorbed by the human body, causing injuries to people from external radiation. The more radiation energy the body receives, the more serious the symptoms of radiation sickness, and the greater the risk of illness, carcinogenesis and teratogenesis.
Symptoms after radiation: dizziness, nausea, vomiting, diarrhea, fatigue, anorexia, leukopenia, skin redness, ulcer, bleeding, hair loss, deep sleep, shock, leukemia, deformation, cancer and death.