Solar energy is an electromagnetic wave, which are divided into several parts of the spectrum:
- X-rays - with the shortest wavelength (below 2 nm);
- wavelength ultraviolet radiation range from 2 to 400 nm;
- visible part of the light that is captured by the human eye and animal (400-750 nm);
- warm oxidative (infrared) radiation (above 750 nm).
Each piece finds its application and is of great importance in the life of the planet and all of its biomass.We consider that the rays are in a range from 2 to 400 nm, where they are used and what role in people's lives.
history of the discovery of UV radiation
first mention dating back to the XIII century in the descriptions of the philosopher from India.He wrote about the invisible violet light, which they have been detected.However, the technical possibilities of the time clearly lacking to confirm this experiment and explore in detail.
succeeded is it five centuries later, German physicist Ritter.It was he who conducted experiments on the silver ch
Thus, in 1842 it was discovered ultraviolet radiation, properties and applications which subsequently underwent a thorough review and study by different scholars.A great contribution to this is made by people like Alexander Becquerel, Varshaver, Dantzig, Macedonio Melloni, Frank, Parfenov, Galanin and others.
What is ultraviolet radiation, the use of which today is so widely in different sectors of human activity?Firstly, it should indicate that there is this kind of light spectrum only at very high temperatures between 1500 and 20000S.It is in this range of UV peak activity affected.
On the physical nature of this electromagnetic wave, the length of which varies quite widely - between 10 (sometimes 2) to 400 nm.The entire range of the radiation is divided into two areas:
- Middle spectrum.It comes to Earth through the atmosphere and the ozone layer from the sun.The wavelength - 380-200 nm.
- Far (vacuum).Actively absorbed by ozone, oxygen, atmospheric components.Explore manages only by special vacuum device, for which he received his name.Wavelength - 200-2 nm.
There is a classification of its own, which is ultraviolet radiation.Features and applications is one of them.
- longwave black light (UV-A).
- germicidal shortwave (UV-C).
- medium wave UV-B.
wavelength of ultraviolet radiation in each species has its own, but they are all in general have previously identified limits.
interesting is UV-A, or the so-called black light.The fact that the spectrum has a wavelength of 400-315 nm.It is located on the border of the visible light that the human eye can capture.Therefore such radiation passing through certain objects or tissue can be transferred to the visible violet light, and people distinguish it as black, dark blue or dark purple.
spectra, which provide sources of ultraviolet radiation can be of three types:
- molecular (Way).
first characteristic of atoms, ions, gases.The second group - for recombination, bremsstrahlung.Sources of the third type are most often found in the study of rarefied molecular gases.
sources of ultraviolet radiation
main sources of UV rays are divided into three broad categories:
- natural or nature;
- artificial, man-made;
The first group includes the only kind of the hub and the emitter - the sun.This orb gives you the most powerful charge of this type of waves that can pass through the ozone layer and reach the Earth's surface.However, not all weight.Scientists have theorized that life on Earth originated only when the ozone shield has become to protect it from excessive penetration of harmful in high concentrations of UV radiation.
It was during this period were able to exist protein molecules, nucleic acids and ATP.Until today, the ozone layer comes into close cooperation with the bulk of UV-A, UV-B and UV-C, neutralizing them and not letting pass through.Therefore, the protection against ultraviolet radiation of the planet - its only merit.
What determines the concentration of UV light penetrating the Earth?There are several key factors:
- ozone holes;
- height solstice;
- atmospheric dispersion;
- degree of reflection rays from the Earth's natural surfaces;
- state vapor cloud.
range of ultraviolet radiation penetrating the Earth from the Sun varies from 200 to 400 nm.
following sources - is artificial.These include all those instruments, devices, technical facilities, which were constructed by man to obtain the desired spectrum of light with a wavelength of specified parameters.This was done in order to obtain the ultraviolet radiation, the use of which can be extremely useful in various fields.For artificial sources include:
- erithema lamps having the ability to activate the synthesis of vitamin D in the skin.It prevents rickets and diseases cures it.
- Apparatus for tanning salons, where people get not only a beautiful natural tan, and treated for diseases arising from the lack of openness of sunlight (so-called winter depression).
- Lighting attractants allows you to fight against insects in a space safe for humans.
- Mercury quartz devices.
- luminescent device.
- Xenon lamp.
- HID device.
- -temperature plasma.
- synchrotron radiation accelerators.
Another type of sources - lasers.Their work is based on the generation of various gases - both inert and not.The sources can be:
- organic scintillators;
recently, about 4 years ago, was invented laser operating in the free electrons.The length of the ultraviolet radiation it is equal to that observed in vacuum.Laser UV distributors used in biotechnological, microbiological studies, mass spectrometry and so forth.
biological effects on organisms
effect of ultraviolet radiation on living beings in two ways.On the one hand by its lack of disease may occur.It became clear only at the beginning of the last century.Artificial radiation special UV-A in the required standards capable of:
- intensify the work of immunity;
- cause the formation of important vasodilator compounds (histamine, for example);
- strengthen the skin and muscular system;
- improve lung function, increase the intensity of gas exchange;
- affect the speed and quality of metabolism;
- improve the tone of the body, activating the production of hormones;
- increase the permeability of blood vessels in the skin.
If UV-A in a sufficient amount is ingested, then it does not occur for diseases such as depression or winter light deprivation, and significantly reduced the risk of developing rickets.
Effect of ultraviolet radiation on the organism can be of the following types:
These properties largely explains the widespread use of UV in medical facilities of any type.
However, besides these advantages, there are downsides.There are a number of diseases and ailments that can be purchased, if not dopoluchaet or, conversely, to take in excessive amounts considered wave.
- skin cancer.This is the most dangerous effects of ultraviolet radiation.Melanoma is able to be formed by excessive influence of waves from any source - both natural and created by human beings.This is especially true lovers of tanning.In all necessary measure and caution.
- devastating effect on the retina of the eyeball.In other words, can develop cataracts, pterygium, or burns shell.The harmful effects of excessive UV on the eye has been proven by scientists for a long time and is confirmed by experimental data.Therefore, when using such sources should observe safety rules.On the street, you can protect yourself by using sunglasses.However, in this case, should be wary of fakes, because if the glass is not equipped with UV-repellent filters, the destructive effect will be even stronger.
- burns on the skin.In the summer, they can earn if uncontrolled long time to expose yourself to UV.In winter, you can get them out of the features of the snow almost entirely reflect these waves.Therefore irradiation occurs from the sun and from the snow.
- Aging.If people had long been under the influence of UV, then they start to show signs of early skin aging: slackness, wrinkles, laxity.It comes from the fact that the protective barrier function of sheets weakened and broken.
- impact of the effects of time.Is to show negative impacts not at a young age, and closer to retirement.
All of these results are the consequences of violations of the UV dose, ieThey arise when the use of ultraviolet radiation is carried out rationally, correctly, and without complying with the security measures.
Ultraviolet radiation: application
The main areas of use are repelled from the properties of the substance.This is true for spectral wave radiation.So, the main characteristics of UV on which to base its application are:
- reactivity high level;
- bactericidal effect on the organisms;
- ability to cause the glow of various substances in different shades, visible to the human eye (luminescence).
It makes extensive use of ultra-violet radiation.Applications include:
- spectrometric analysis;
- astronomical research;
- disinfection of drinking water;
- analytical study of minerals;
- UV filters;
- for catching insects;
- to get rid of bacteria and viruses.
each of these areas uses a certain type of UV spectrum and with its wavelength.Recently, this type of radiation is widely used in chemical and physical studies (determination electron configuration of the atoms, molecules and crystalline structure of various compounds, the work with the ions, analysis physical transformations at different space objects).
There is another feature of the effects of UV on the matter.Some polymeric materials capable of decomposing under the influence of intense permanent source of these waves.For example, such as:
- any pressure polyethylene;
- polymethyl methacrylate or acrylic glass.
What has been the impact?Products from these materials lose their color, crack, fade and eventually destroyed.Therefore, they are called sensitive polymers.This feature of the carbon chain degradation under conditions of solar irradiance are actively using nanotechnology, X-ray lithography, transplantation and other areas.This is done mainly to smooth the surface roughness products.
Spectrometry - the main area of analytical chemistry, which specializes in the identification of compounds and formulations of ability to absorb ultraviolet light of a certain wavelength.It turns out that the spectra are unique to each substance, so you can classify them according to the results spectrometry.
Also, the use of ultraviolet germicidal radiation is to attract and kill insects.The action is based on the ability of the eye to capture the insect invisible man shortwave spectrum.Therefore, the animals are flying to the source, and where exposed to destruction.
use of solariums - special units of vertical and horizontal type in which the human body is exposed to UV-A.This is done to enhance the production of melanin in the skin, giving it a darker color, smoothness.Furthermore, in this it is dried inflammation and destroy harmful bacteria on the surface of the sheets.Particular attention should be given to protecting the eyes, sensitive areas.
Application of UV radiation in medicine is also based on its ability to destroy the invisible living organisms - bacteria and viruses, and on the features that occur in the body during literate lighting artificial or natural radiation.
main indications for the treatment of UV can be described in a few paragraphs:
- All kinds of inflammation, wounds, open type, open and festering stitches.
- For injuries of tissues and bones.
- burns, frostbite and skin diseases.
- treatment of respiratory ailments, tuberculosis, bronchial asthma.
- When the origin and development of various kinds of infectious diseases.
- When ailments, accompanied by severe pain, neuralgia.
- diseases of the throat and nasal cavity.
- rickets and trophic ulcer.
- dental diseases.
- Regulation bloodstream pressure, normalization of the heart.
- development of cancerous tumors.
- atherosclerosis, renal failure, and some other states.
All of these diseases can have very serious consequences for the organism.Therefore, treatment and prevention of the use of UV - it is a real medical discovery, save thousands and millions of human lives, preserves and restores their health.
Another usage UV medical and biological point of view - is the disinfection of premises, sterilization of instruments and working surfaces.The action is based on the ability to inhibit the development of UV and replication of DNA molecules, which leads to their extinction.Bacteria, fungi, protozoa and viruses are killed.
The main problem when using such radiation for sterilization and disinfection of the premises is the area of lighting.After all, are killed only with the direct effects of direct waves.All that remains outside, continues to exist.
Analytical work with minerals
ability to induce luminescence from substances allows the use of UV for the analysis of qualitative composition of minerals and precious rocks.In this regard, very interesting are the precious, semi-precious and precious stones.There are all shades they do not bombarded with cathode waves!Very interesting about this wrote Malakhov, a famous geologist.His work describes observations of the glowing color palette, which is capable of producing minerals in different sources of exposure.
example, topaz, which is in the visible spectrum has a beautiful deep blue color when irradiated lights bright green and emerald - red.Pearls do not give any specific color and shimmering multicolored.The spectacle of the result is simply fantastic.
If the composition of the studied rocks includes impurities of uranium, it will show the flashing green.