Ah, the radiation of radioactive materials is just gamma flow, alpha flow and beta flow, but the consequences of exposure to radioactive materials such as uranium, iridium and plutonium are the same as those of you under the desk lamp. ............
Supplement: Just check the information:
1.γ rays are produced by radioactive isotopes such as 60Co or 137Cs. It is a kind of high-energy electromagnetic wave, with short wave length (0.00 1-0.000 1nm), strong penetration and long range, which can irradiate many substances at one time, and the dose is relatively uniform and dangerous, so it must be shielded (a few centimeters of lead plate or a few meters of concrete wall).
X-rays are high-energy electromagnetic waves generated by X-ray machines. The wavelength is longer than gamma rays, the range is slightly shorter, and the penetration is not as good as gamma rays. If there is danger, shield (a few millimeters of lead plate).
3. When beta rays decay from radioactive isotopes (such as 32P, 35S, etc.). ), releasing negatively charged particles. Short range, weak air penetration. Ionization in organisms is stronger than gamma rays and x-rays.
4. Neutron uncharged particle flow. The radiation source is a nuclear reactor, accelerator or neutron generator. When the nucleus is bombarded by foreign particles and released from the nucleus, a nuclear reaction occurs.
Neutrons are divided into fast neutrons, slow neutrons and thermal neutrons according to energy.
Neutron ionization density is high, which often causes big mutation.
Thermal neutrons and fast neutrons are widely used in radiation breeding.
5. Ultraviolet is a kind of non-ionizing radiation with weak penetration.
Nucleic acid is excited after absorbing ultraviolet energy of a certain wavelength, which strengthens the activity of organic compounds and causes variation. Can be used for treating pollen of microorganisms and plants.
6. Laser is a new light source developed in 1960s.
Laser is also an electromagnetic wave. Longer wavelength and lower energy. Because of its good directivity, it is only 0. 1. Left-right deviation, high brightness per unit area, good monochromaticity, can make biological cells absorb * * * vibration, leading to atomic and molecular energy state excitation or atomic and molecular ionization, thus causing biological internal variation.
Because of the different ionization density, the biological effects of various rays are different, and the change rate is also different. In order to obtain higher favorable mutation, it is necessary to choose appropriate rays, but due to factors such as ray source, equipment conditions and safety, gamma rays and X rays are the most commonly used at present.
Add one more thing:
All objects in nature always transfer heat to the outside world in the form of electromagnetic waves as long as the temperature is above absolute zero. This way of transmitting energy is called radiation. The energy released by an object through radiation is called radiant energy. Radiation is calculated in roentgen per hour (r)
An important feature of radiation is "equivalence". Objects (gases) radiate outward regardless of temperature. Object A can radiate to object B, and object B can also radiate to object A ... This is different from conduction, which is unidirectional. Anyone exposed to radiation should wash his whole body thoroughly with soap and plenty of water, and seek the help of a doctor or expert immediately! (The picture shows the warning sign "Danger of radioactive materials, beware of radiation")
When radiant energy is absorbed by an object, it will produce a thermal effect. Different radiant energy absorbed by objects leads to different temperatures. Therefore, radiation is an important way to convert energy into heat. Radiation heat transfer is a process of transferring heat between hot and cold objects by electromagnetic radiation, which belongs to non-contact heat transfer and can also be carried out in vacuum. Theoretically, the electromagnetic waves emitted by objects are distributed in the whole spectral range, but in the temperature range encountered in industry, the practical significance is the thermal radiation with the wavelength of 0.38 ~ 1000 micron, and in the infrared (also known as thermal radiation) section, most of them are in the range of 0.76 ~ 20 micron. The so-called infrared heating is to use the thermal radiation of this section. It is very important to study the law of thermal radiation for the reasonable design of heat transfer in the furnace, and it is also of positive significance for the labor protection of operators in the high temperature furnace. When a system needs heat preservation, even if the temperature of the system is not high, the influence of radiation heat transfer can not be ignored. For example, silver plating on thermos bottles is to reduce the heat loss caused by radiation heat transfer. The basic concept of thermal radiation Any object continuously absorbs the radiant energy of the surrounding objects while emitting radiant energy. The difference between the energy radiated by an object and the energy absorbed is the net energy it transmits. The radiation ability of an object (that is, the energy radiated from the surface per unit time) increases rapidly with the increase of temperature. Generally speaking, when an object is radiated by other objects (energy is Q), the part that is absorbed and converted into heat energy is QA, the part that is reflected is QR and the part that passes through the object is QD. Obviously, these parts are related to the total energy: QA+QR+QD=Q If A=QA/Q is called absorption rate, R=QR/Q is called reflectivity, and D = QD.
If A= 1 and R=D=0 of an object, that is, the thermal radiation energy reaching the surface of the object is completely absorbed, then the object is called an absolute blackbody, or blackbody for short. If R= 1 and A=D=0, that is, all the thermal radiation energy reaching the surface of the object is reflected; When this reflection is regular, this object is called a mirror; If it is random reflection, it is called absolute white body. If D= 1 and A=R=0, that is, all the energy of thermal radiation reaching the surface of the object passes through the object, which is called a diatherm. In fact, there is no absolute blackbody or absolute white body, only some objects are close to absolute blackbody or absolute white body. For example, the surface of dark black paint is close to blackbody, and the absorption rate is 0.97 ~ 0.98; The polished copper surface is close to the white body, and the reflectivity can reach 0.97. The absorption and reflection characteristics of solid surface are mainly influenced by surface condition and color, and the influence of surface condition is often greater than color. Solids and liquids are generally unaffected by heat. The energy of thermal radiation is completely absorbed only after passing through the solid or liquid surface for a short distance (generally less than 1mm, and after passing through the metal surface 1μm). Gases have little ability to reflect thermal radiation energy. Monoatomic and symmetric diatomic gases (such as argon, helium, H2, N2, oxygen, etc. ) can be regarded as a diathermant at general temperature, while polyatomic gases (such as CO2, H2O, SO2, NH3, CH4, etc. ) has a considerable absorption capacity in a specific wavelength range.
Radiation is emitted in the form of electromagnetic waves and particles (such as alpha particles and beta particles). Radio waves and light waves are electromagnetic waves. Their propagation speed is very fast, which is the same as that of light wave in vacuum (3× 10 10 cm/s), but slightly slower in air.
Electromagnetic wave is a composite wave composed of waves with different wavelengths. Its wavelength ranges from cosmic rays of10e-10μ m (1μ m =10e-4cm) to radio waves of several kilometers wavelength. X-rays, X-rays, ultraviolet rays, visible light, infrared rays, ultrashort waves and long-wave radio waves all belong to the scope of electromagnetic waves. Visible to the naked eye is a short electromagnetic wave, which is called visible light from 0.4-0.76 micron. Visible light, after being split by a prism, becomes a light band composed of seven colors: red, orange, yellow, green, cyan, blue and purple. This band of light is called spectrum. Among them, the wavelength of red light is the longest, the wavelength of purple light is the shortest, and the wavelengths of other colors are in between. There are infrared and radio waves whose wavelength is longer than red light (>: 0.76 micron); The wavelength is shorter than violet light (
The wavelength of solar radiation is mainly 0. 15-4 micron, and the maximum radiation wavelength is 0.5 micron on average. The radiation wavelength of ground and atmosphere is mainly 3- 120 micron, and the maximum radiation wavelength is 10 micron on average. It is customary to call the former short-wave radiation and the latter long-wave radiation.
Third supplement: Oh, the information is relatively complete.
A: What's the difference between electromagnetic radiation and electromagnetic radiation pollution?
Q: Actually, electromagnetic radiation and electromagnetic radiation pollution are two concepts. Any charged body has electromagnetic radiation. When the intensity of electromagnetic radiation exceeds the national standard, it will have negative effects and cause different diseases and harms to the human body. This part of radiation that exceeds the standard electromagnetic field strength is called electromagnetic radiation pollution.
A: What's the effect of mobile phone base station radiation on people's health?
Q: This is a common phenomenon. Many residential buildings in the city have installed mobile phone base stations. Some citizens are worried about whether the electromagnetic radiation generated by this equipment will cause harm to the human body. In fact, there is no need to worry about this problem. The difference between cell phone radiation and cell phone base station radiation. Generally, the electromagnetic radiation value of mobile phone is between 0.03 and 0.7, while the radiation value of mobile phone base station is 10 microwatt. The radiation value generated by the mobile phone base station is not much higher than that of the mobile phone! In addition, the closer the electromagnetic radiation, the longer the radiation time and the deeper the damage! Moreover, the distance between the mobile phone base station installed on the roof of our general residents' home and us is a safe distance, so don't worry!
Radiation index of electrical appliances
The radiation index of electrical appliances is divided into five points. Anyone who is rated as five points is seriously exceeding the standard, so you should pay attention. Samsung and above also belong to the over-standard range, which should also attract your attention; One star is safe and can be used with confidence.
There are two levels of electromagnetic radiation, among which the unit of power frequency band is μT, and the radiation above 0.4μT belongs to strong radiation, which is harmful to human body and prone to leukemia after long-term contact. If the radiation is below 0.4μT, it is relatively safe. The unit of radio frequency electromagnetic wave is μW/㎝2.
1. TV
The traditional cathode ray tube TV cathode ray tube was tested first. First, we test it at close range. Within the first half of a meter, the radiation value generated during normal startup is 0. 12μT, 0.30μT during normal viewing, 0.27μT during channel changing, 0.1/μ t during standby, and the radiation value on the side is 0.0 during normal viewing.
Because most people watch TV at a distance of about 3 meters, we also made a test on the front 3 meters, and found that the radiation has a great degree of attenuation: the startup, normal viewing, channel changing and standby state are all 0. 12μT, and the test results show that the normal viewing of traditional CRT TV will not cause harm. But to our surprise, the radiation intensity behind it is relatively high, and the radiation value reaches 4.8μT within half a meter after starting the machine, and the radiation through glass and wooden boards has not decreased, even through the wall with a thickness of 10 cm, the radiation value is 0.9 μ t. Please be careful if the back of your TV is facing the bedside of your bedroom. But usually people have different time to rest and watch TV, so it is not a big problem.
Look at the plasma TV again, the front is half a meter, the starting, watching and channel changing are 0. 1 1μT, the standby is 0. 12μT, and the side is 0.11μ t; The front is 3 meters, and the TV is 0. 12μT when turned on, 0. 14μT when viewed normally, and 0. 1 1μT when turned on or on standby. According to the test results, the radiation intensity of plasma is less than that of traditional TV.
When the rear projection TV is viewed normally, it is 0. 12μT, 0. 19μT and 0. 14μ t near the front, side and back of the fuselage, respectively. First half meter 0.11μ t; 3 meters ahead is 0.1μ t.
The most reassuring thing in TV series is LCD TV. No matter whether the front is half a meter or three meters, the instantaneous test results at startup, normal viewing, channel changing and standby state are all 0. 1μT, while the side is only 0. 1 1μT, and basically the radiation intensity has not changed.
Test results: Comparing the three kinds of TVs, we can easily find that LCD TV and rear projection TV have the smallest radiation, plasma TV has a little stronger radiation, and CRT TV is bigger, but it is mainly behind TV. It is recommended that you keep a certain distance when watching, especially for children.
2.DVD player and home theater
The popular home theater in recent years, that is, DVD player plus sound system, is closely related to the test results, such as DVD 1.2μT, OK player 1.2μT, power amplifier 1.24μT, small speaker 1.5μT, and large speaker 0.49 μ t.
Tip: I suggest you use home theater as little as possible. If you want to sing, you'd better go to KTV.
CRT monitor LCD monitor desktop computer host small speaker notebook computer
People always think that CRT monitors emit a lot of radiation. Is it what everyone thinks? We tested it first. The front of the display is close to 1.00μT, and the side of the display is close to 0.55μT, which is not small! Look at the center of the display screen, the distance is 0.03 meters, and the radiation is still 0.55 μ t. Is this CRT monitor really as big as we thought? To further confirm, we began to look for its safe distance. In this way, when the distance is 0.2 meters, the radiation in front of the display screen will be attenuated to 0.18 μ t, and it seems that the CRT display can be used safely as long as the distance is 0.2 meters. Some viewers asked if it was as big as CRT TV, and it was not big after the test. Some people like to use radiation screensavers, so is it effective? We also specially tested it, and the screensaver radiation only decreased by 10%. Screen saver doesn't seem to have much effect.
Radiation index of CRT display: ★★★☆☆
Now liquid crystal display is replacing the traditional display, and we have also tested it. The front of the display screen is 0. 1 1μT, the instant of startup is 0. 12μT, the time of shutdown is 0.1/μ t, and the side of the display screen is 0.12μ t. It seems that LCD is really reassuring.
Radiation index of LCD: ★ ☆ ☆ ☆.
Let's look at the mainframe of the desktop computer again. The front is 0. 17μT, but the central radiation of the console panel is slightly stronger, with distances of 0.03m and 0.26 μ t; The side of the main engine is 0.29μT, and the center of the left side of the chassis is 0.03 m and 0.23μT apart. The back is 0.46μT, but we are usually at a certain distance from the back of the mainframe, so the impact is not great. Also, the startup moment and standby state are both 0.17 μ t, and one more thing to say is that if the power connection of the desktop computer is reconnected, the radiation is 0.47μT, so keep a distance when using the desktop computer again.
Radiation index of desktop computer host: ★★★☆☆
But the next test is not very optimistic, subwoofer speaker, the center of the operation panel, the distance is 0.03 meters, 0.63 μ t; The center of the right side of the speaker is 0.03m and 5.68 μ t away; Radiation is not small, so what is its safe distance? After careful testing, it is found that when the distance is 0.4 meters, its radiation is reduced to 0. 17μT ... So the subwoofer speaker has serious radiation, and it should be kept at least half a meter away when using it.
Radiation index of subwoofer speaker: ★★★★★☆.
Finally, I want to talk about the notebook computer, which is 0. 1. 13μT in front of the display screen, 0.3 m in front of the display screen, 0. 13μT on the side of the display screen, 0. 19μT on the keyboard and 0.22μT on the power adapter. The test results show that the radiation of notebook keyboard is slightly stronger, and the power adapter is the largest.
Notebook radiation index: ★ ☆ ☆ ☆.
Tip: the radiation of LCD screen is very small, and the CRT monitor is slightly larger, but they are all within the safe range; The radiation on the back and side of the host is large, so it is strongly recommended that you do not open the chassis for the convenience of heat dissipation. The subwoofer has serious radiation, so keep a distance of at least half a meter when using it. The radiation of the notebook is concentrated above the keyboard, so keep a distance from the power adapter when using the notebook.
Oh, yes, it is said that this computer and notebook don't radiate much, but the photoelectric mouse turns red and blue, which is very scary. Is there radiation? Are the radiation of wireless mouse and keyboard less than that of ordinary ones? And that WLAN transmitter! There are digital devices, digital cameras, MP3 and MP4.
To tell you the truth, this battery-powered DC appliance is the safest.
Ordinary mouse: 0. 1μT
Ordinary keyboard: 0. 1 1μT
Wireless mouse: 0.53μT (above the mouse)
Wireless keyboard: 0.96μT (above the keyboard)
Wireless gateway: 0. 15μT (above the gateway)
And the printer: 0.11μ t.
Digital camera power adapter: 0. 1 1μT
MP4 power adapter: 0. 16μT
Radiation index of power adapter for ordinary mouse, keyboard, wireless gateway, printer, digital camera and MP4: ★☆☆☆☆;
Radiation index of wireless mouse and keyboard: ★★★☆☆
Tip: Ordinary keyboard and mouse, as well as wireless gateway, printer, digital camera and MP4 power supply have little radiation, so you can use them safely. However, wireless keyboards and wireless mice radiate a lot.
3. Refrigeration and heating equipment, electric blanket
The air conditioner in the bedroom has the longest time and the largest power. Fortunately, its radiation is only 0. 1μT at the moment of switching on and off and in normal use, and the radiation value does not change much in various modes such as mute and sleep.
In winter, some families like to use small electric heaters, heaters and other heating appliances, but the radiation is not small. Let's look at the infrared electric heater first. Test results of distance 1. 8μT means that the radiation above is 1.8 μ t, and the side is 5.4μT, so the radiation intensity is very high. We tested at a distance of 1mm, and the radiation decreased to 0.65438. The test result of heater close contact is 9. 3μT, that is, 0.34μT on the front and 0.25μT on the back at half a meter. However, the most reassuring thing is the Youting electric heater, which is 0.19 μ t in the center when it is used in high grade; The center of the side is 0. 18μT when it is near, and 0. 18μT when it is half a meter.
When high-grade electric blanket is used, it is 0.7 1μT near the power supply, 1. 1.5μT at the left corner of the opposite side of the power supply, 0.7 1μT at the right corner of the opposite side of the power supply, and 0.55 μ t at the center of the electric blanket. At low gear, the left corner of the reverse side of the power supply is 0.70μT, and the right corner of the reverse side of the power supply is 0.49μT t. It seems that the radiation of the electric blanket is really not small.
Another big radiation source in the bedroom is the electric fan, with low-grade wind of 2.6μT and high-grade wind of 0.9 μ t. But over 2m, the radiation decays to 0.11μ t.
Tip: The air conditioner has little radiation, so you can use it safely. However, infrared tube electric heaters, heaters and electric fans radiate a lot, so it is recommended to keep a distance of at least one meter when using them. Electric blankets also radiate a lot, so it is recommended to use them less.
Humidifier, air purifier
In the test, we found that this fan humidifier has the largest radiation, and the test results close to it are 49μT, low-grade 15μT and high-grade 32μT, but when it exceeds 1m, it drops to 0.52 μ t. The test result of the ultrasonic spray humidifier is 9μT and 0.22μT outside 1 meter. The test result of the air purifier close to it is 0.35μT, which drops to 0. 12μT in the range of 0.5m m.
Tip: Humidifier and air purifier should not be too close to human body.
Humidifier radiation index: ★★★★★
Radiation index of air purifier: ★★★☆☆
Induction cooker electric hot pot microwave oven
People who like to eat hot pot with an induction cooker should pay attention. Its radiation is not small. Look at the test results 0. 1 m 2.80μT above the induction cooker, 0.3 m 1.40μT above the induction cooker, 8.70μT in front of the induction cooker, and 0.3 m 1.00μT in front of the induction cooker. Looking at the test of electric hot pot, the high-end startup is 0.53μT and the shutdown is 0.13 μ t.
The test results show that the electromagnetic oven has a large radiation, and the electric hot pot is better than the electromagnetic oven.
Then we first tested the microwave oven that everyone was most concerned about, and found that the radiation at the door of the microwave oven was the biggest, so we made a detailed test:
Mid-range fire time: 0.03 m17.32 μ w/2 before crack,
0.3m before the crack: 2.01μ w/㎝ 2
Before crack 1m:0.4 1μW/㎝2
Center of microwave oven door: 1m away from the door 150.7μW/㎝2.
The test results show that the microwave oven radiates the most when it is started (the value (0.05 m away from the door) is about 18 to 22μW/㎝2).
Tip: the electromagnetic oven has a large radiation, while the electric hot pot has a relatively small radiation. It is suggested that the use time of induction cooker and electric hot pot should not be too long, and a certain distance should be kept when using. The microwave oven radiates the most when it is started. It is recommended not to get too close when cooking in the microwave oven.
Radiation index: ★★★★★★★★★★
Refrigerator, range hood, ozone disinfection cabinet ozone machine, rice cooker, electric baking pan, electric kettle, juicer, soymilk machine.
Refrigerator: 0.13μ t outside the door; 0. 16μT inside the door (open the door).
Range hood: 0. 1m on the front is 0.38μT, and 0. 1m on the front is 0.1μ t at the moment of power failure.
Ozone disinfection cabinet: Open the door 0.14 μ t t.
Ozone machine: (open cover) 0.55μT
Rice cooker: (front) 0. 16μT
Electric baking pan: (near the top) 3.60μT t t.
Electric kettle: (close to)1.20μ t; (0. 1m) 0.30 μ t
Juicer: 10.00μT
Soymilk machine: (close to) 0.86 μ t; (0. 1m) 0.30 μ t
Tip: Refrigerators, ozone disinfection cabinet and rice cookers can be used with confidence, with less radiation; The radiation of electric baking pans and range hoods is slightly larger, which belongs to the early warning range. Be careful not to stick them too close when using. Ozone machine, soymilk machine and juicer all have relatively high radiation, so it is best not to let children use them.
Vacuum cleaner, electric iron, hair dryer, power wiring board
We have tested this big vacuum cleaner before, and the radiation under normal use is 15μT, but it is not small. This small hand-held vacuum cleaner is still very popular now. How much radiation does it have? We also did the test, and the distance from the handle was 0.03 m: 6.64 μ t; Left center: 4.22 μ t; But if you use it like this, its radiation will decay to a safe range, and the back is 0.2m: 0.15 μ t T. ..
Radiation index of large vacuum cleaner: ★★★★★
Radiation index of small vacuum cleaner: ★★★★★☆.
The radiation of the electric iron is also quite large. We made a detailed test and found that the radiation of the electric iron will increase when it is heated. In the heating state, the handle is1.22μ t; However, under the condition of constant temperature, the radiation decays to 0. 12 μ t, so if ironing clothes, it is best to heat them once and then continue heating them later. Never iron clothes while heating.
Radiation index of electric iron: ★★★★★☆.
Hair dryer is also a big radiation source we found. In the previous test, the low grade was 4.20μT and the high grade was10.00 μ t. After that, the different parts of the hair dryer were tested in detail under the condition of hot air, and the handle was 0.03 m,10.95 μ t; Air outlet, 7. 16μT, it seems that the hair dryer is really going to be used less.
Radiation index of hair dryer: ★★★★★
Another thing to remind everyone is that if the power terminal board is not connected to electrical equipment, the radiation is only 0. 1 1μT, which is not large; However, when connecting high-power electrical equipment, when the distance is 0.03m, its radiation can be 1.25μT ... which will attract your attention.
Radiation index of power terminal board (in use): ★★★★★☆.
Text: The radiation of vacuum cleaner and hair dryer is large, and the radiation of electric iron is not small. Keep away from children when using, and the radiation of power terminal board should also attract your attention, so don't put it on the bedside.
Electric footbath, treadmill, fat exercise machine
This is a popular electric footbath. Let's see how much radiation it has. 0.03m from the power line, 2.20μT t t. ..
Radiation index of electric footbath: ★★★☆☆
Others like exercising at home. How much radiation does this treadmill have? When the treadmill works, the panel is 0. 15μT, the front of the conveyor belt is 3.90μT, and the tail of the conveyor belt is 0.11μ t. ..
Treadmill radiation index: ★★☆☆.
Ladies love beauty and always like to lose weight. Let's see how much radiation the fat exercise machine has. Fat fitness machine, side, high gear, 0.03 m, 5.48 μ t.
Radiation index of fat exercise machine: ★★★★★
Tip: The electric footbath and fat exercise machine radiate greatly, and the front part of the conveyor belt of the treadmill radiates greatly.
What kind of spectrograph is not too radioactive?
In fact, as long as it is infrared, it is not within the scope of our test, and it is not electromagnetic radiation. So, you can use it with confidence.
4. lamps and lanterns
Let's start with the desk lamp. This is the desk lamp in the master bedroom, with a radiation value of 0.17 μ t, which is an energy-saving eye protection desk lamp for children, and the radiation value is also 0. 1 1μ t, and the old desk lamp is used in the study, with a radiation value of 0.1μ t.
The detection results of fluorescent lamps are: master bedroom 0. 12μT, living room 0. 18μT, study room 0. 1 1 μ t, and a cartoon wall lamp that children like, with radiation value of 0.11.
Tip: All kinds of lamps are qualified in radiation and can be used safely.
It can be avoided without spending a penny. One of the most effective ways is to keep a distance, and it must be a safe distance of more than 3 meters.
If you are at home, make reasonable arrangements, because experts suggest that it is best not to wear protective clothing. The human body itself is a big conductor, and wearing it can only introduce shielded radiation into the human body. Moreover, there is no clear material standard for protective clothing, and the price is uneven. Therefore, it is recommended that you do not trust the role of protective clothing.
Sweat! ! !
All objects in nature always transfer heat to the outside world in the form of electromagnetic waves as long as the temperature is above absolute zero. This way of transmitting energy is called radiation. The energy released by an object through radiation is called radiant energy.
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