Laser radiation

Researches workers paid attention, that influence of laser radiation on biological fabrics can result in|to| thermal, shock action|act| and light|photic| pressure. Depending on the different|diverse| circumstances, displays of every effect separately whether their total action|act| the enough different|diverse| values|importances,meaning| can acquire|buys|.

At large|great,big| intensity and small to the duration | impulse look after shock action|act| of laser radiation, which|what| spreads|widened| quickly enough and results in|to| the damage of internal|inlying| fabrics. Thus quite the external displays are unnoticeable. On an organism a thermal effect which|what| burns can appear through|from,because of| is|appears| the almost staple of action|act| of laser radiation. Also there can be more serious consequences, such as destruction, deformation and even partial evaporation of cellular structures. At action|act| of laser radiation of less|lesser,smaller| intensities it is possible to look after the visible changes|changing| at an organism, namely violation of pigmentation, turning red with clear enough borders| of area|zone|, that tested|feels| the defeat.

Skinning|skins| shells to a great extent|largely| protect|defends| the internal|inlying| systems of organism from the serious defeats as a result of|because of,owing to| action|act| to the laser. But some|certain| researches rotined an interesting|curious| result - sometimes the irradiation of areas of skin can result in|to| violation of row|file| of the systems of organism, in particular|including| nervous and cardiovascular |. By investigation|result| even not very much high doses of laser radiation can become|becomes|

almost such symptoms, as well as at SHF-irradiation. This and the unstable state|figure,camp,mill| of arteriotony, and violation of cardiac|hearty,kind| rhythm, and also fatigue, irritation and other. These violations are reverse|return| and are a characteristic to disappear in course of time after some|certain| rest.

As well as SHF |, most the laser radiation harms to the eyes. Most danger is observed|exists| in an ultraviolet range. On such conditions coagulation of albumen can happen corneas and burn of mucus shell that can entail blindness. Rays|beams| from a visible range are a characteristic to influence on the cages|cells| of retina. From|because of| it there can be both temporal blindness and loss of eyesight as a result of|because of,owing to| burn. The radiation of infra-red range is|appears| more dangerous and also can result in|to| blindness.

That it is possible to re-done|accomplishes| a conclusion|inference,withdrawal|, that the laser irradiation can injure|damages| all structures of eye. By virtue of that an eye is|appears| the optical system, it is possible to look after the indirect | influencing and second-rate effects which|what| are|appears| the reaction of organism on the irradiation also.

At the laser irradiation there are free radicals in biological fabrics. They participate actively in co-operation with molecules and violate|excite| the normal process of exchange of matters in an organism at the level of cages|cells| This leads to a general deterioration of health and accelerates the process of ageing of organism.

2.2 Defence|protection| of organism from the negative influencing of electromagnetic

Fields

For defence|protection| of man from the harmful influencing of the electromagnetic fields norms and standards are adopted. It is needed to mark|notes| that any|some| norms|standards| and standards related|tied| to defence|protection| of man from the harmful effect, always show itself a compromise between advantages of the use of new technologies and new technique and possible risk caused|called| this use.

Pursuant to гост| of 12.1.006-84,ГДР №4131-86, The СН№5802-91 "Electromagnetic fields of radio frequencies" are engulfed|embraced| by the range of frequencies 60 kHz|...300 MHz. Estimation|appraisal| of ЕMF| in a range 60 kHz |...300 MHz is conducted separately from the electric and magnetic constituents of the field. Possible levels during|for| a working day on an electric constituent not must exceed 50 V/m going down by degrees 5 V/m on the measure of increase|rise| of frequency. On a magnetic constituent levels are set only for the separate areas of range: 5 А/m for frequencies 60 kHz |...1,5 MHz and 0,3 And|but| for frequencies 30...50 Mhz. Exceeding of these standards is assumed, but no more than double, at reduction|abbreviation,shortening| of working day no less as on 50%.

For frequencies 300 MHz...30 GHz| maximum the legitimate values of closeness concerne as a result of division of the rationed size|value| of the power loading for|after| a working day in a time of influencing. The power loading during|for| a working day not must exceed 200 mkWh/ | -

We see that the electromagnetic fields so much|like hell,like sin| influence on a human organism. They negatively influence almost on all systems of organism. That is why|that is why|

it is needed to create the certain|definite| methods of defence|protection| from their action|act|. From such methods such are|appears| most widespread:

· reducing of density of a stream of energy if the given technological process or the equipment allows;

· protection by time (that is restriction of time of a finding in a zone of source of EMF|);

· protection by distance;

· screening of workplace|job| or source|spring|;

· rational planning of workplace|job|;

· application of facilities of the preventive signaling;

· application of facilities of the personal|private| defence|protection|.

For diminishing of influencing of the electromagnetic fields on a personnel which|what| to be in the area|zone| of action|act| of some|certain| radios electronic facilities the row of protective measures|steps| is|appears| a necessity: organizational, nonproduction and treatment and preventive.

Screening is the most effective method of defence|protection|. The electromagnetic field relaxes by a screen as a result of|because of,owing to| origin in the thickness of his|its| field of opposite direction. The degree of easing | of ЕМF| depends on the depth of penetration of boundary-permissible levels of thickness of screen. Than greater permeance of screen and high-frequency of the field which|what| is screened, the less|lesser,smaller| depth of penetration and necessary thickness of screen.

Screen a radiant|spring,source| or workplace|job|. Screens are beating back and suctive.

For defence|protection| of workers from ЕМF| apply grounding screens, sheepskin coats, protective peaks which|what| are set|established| in place of radiation. Facilities of defence|protection| with radio of suctive materials|fabrics| will set in the type of thin rubber carpets, flexible or hard pieces of paralon |, ferromagnetic layers.

For defence|protection| from the electric fields by frequency of 50Гц it is necessary to multiply the height of hanging of phases explorers of power lines (PL) | high tension.

2.3 Defence|protection| from the laser radiation.

Laser safety is the aggregate of technical, sanitary - hygienical|sanitary| and organized measures which|what| provide|secures| the safe terms of labour of personnel at used lasers. Methods of defence|protection| from the laser radiation under divide into collective and individual.

Collective facilities of defence|protection| of radiations: use of the televisional systems of supervision after motion of process; protective screens (sheepskin coats), systems of blocking|locking,deadlock| in signaling; barrage of unsafe zone of the laser|zone|. For the control of laser radiation and determination|definition| of borders

of unsafe zone of the laser apply colorimeteries, photo-electric|photovoltaic| et al devices.

In quality facilities of individual defence|protection| the special against laser glasses, corymbs, masks, technological sidebars and mittens, are used.

For diminishing of danger of impression due to diminishing of diameter of pupil of eye of operator in the apartments there must be good luminosity of workplaces|jobs|. The coefficient|ratio| of natural illumination|lighting| of KLI| must be no less 1,5%, and|but| common lamplight must be evened 300 lx |.

3 Key questions

1. What are the basic|main| sources|springs| of ЕМF| natural origin?

2. What factors influence on changing of parameters of ЕМF| | Earth?

3. How does ЕМF| | influence on the organism of man in HF and UHF | ranges?

4. What features of influencing on a health man of ЕМF| | in a SHF | range?

5. Does the danger of laser irradiation of man consist in what?

6. What does a compromise consist in at certain|definite| norms on the possible levels of constituents of ЕМF| |?

7. What are the most widespread methods of defence|protection| of man from the negative influencing of ЕМF| |?

8. What features of defence|protection| of man from the laser irradiation?

4 Domestic|home| tasks|task|

1. For successful implementation and defence|protection| of practical work of students it is needed in theory to prepare after literature [3,4,9; ap|.: 7,28,31] by the с basic|main| types of ЕМF| and radiations and their influences on living organisms; note| substantive provisions.

2. To prepare to|by| the discussion on key questions.

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