[ultraviolet ray]
Ultraviolet light was discovered by the German scientist Ritter.
Ultraviolet ray is the electromagnetic spectrum of wavelengths from 0.01-0.40 micron radiation. The shorter the wavelength of ultraviolet light, the greater the harm to human skin. Short-wave ultraviolet light can pass through the dermis, medium-wave can enter the dermis.
Ultraviolet classification
Ultraviolet light is the wavelength of 100 ~ 400nm electromagnetic waves. It is subdivided into: near-ultraviolet UVA, far-ultraviolet UVB and ultra-short ultraviolet UVC. ultraviolet rays penetrate the human skin to different degrees.
UVA: can be transmitted to the dermal tissue below, resulting in skin laxity, wrinkles emerge and other evils. It also makes the skin dull and darkens the skin. UVA is equally fierce all year round, regardless of the time of the year.
UVB: will make the skin dry, accelerate skin aging. The human body is subjected to UVB radiation for a long time will cause the skin melanin cells to cause mutation, which is difficult to eliminate the sun spots. But it is easily blocked by clouds and other coverings, and has less penetrating power than UVA.
UVC: UVC is basically absorbed by the ozone layer before it reaches the ground and has little effect on the human body.
Harm of ultraviolet rays
When ultraviolet rays act strongly on the skin, light dermatitis can occur, with erythema, itching, blisters, edema and so on on the skin; serious skin cancer can also be caused.
Ultraviolet light acts on the central nervous system, can appear headache, dizziness, temperature rise. Acting on the eyes, can cause conjunctivitis, keratitis, known as photophthalmitis, and may induce cataracts.
Although ultraviolet rays are present throughout the year, winter sunlight appears to be relatively mild and foggy in the north, but ultraviolet rays are only about 20% weaker than in summer, and still cause great harm to human skin and eyes and other parts of the human body, so you still need to avoid ultraviolet radiation in winter. Long-term ultraviolet radiation is most likely to cause the skin to produce a variety of pigmentation. Therefore, even in the cold winter, outdoor activities should be applied barrier cream or sunscreen. Of course, an SPF of 15 is enough. If you are going out for skiing or staying in the snow for a long time, it is better to wear eye protection to prevent the irritation of ultraviolet rays and strong white light from the snow on the eyes.
In recent years, a large number of chemicals have damaged the ozone layer in the atmosphere, destroying this natural barrier that protects human health. According to a report provided by the National Meteorological Center, the total amount of atmospheric ozone layer in China has been decreasing year by year since 1979, and the ozone layer has decreased by 14% in 20 years. For every 1% decrease in the ozone layer, the incidence of skin cancer will increase by 3%. Currently, the Beijing Meteorological Bureau has released the city's ultraviolet index to help people properly prevent ultraviolet radiation.
The Beijing Municipal Bureau of Meteorology reminds people that when UV rays are the weakest (0-2 levels), there is no great impact on the human body, and you can wear a sun hat when you go out; when UV rays reach 3 levels, you need to prepare sunglasses in addition to a sun hat when you go out and put sunscreen on your body to avoid the harm of the sun's radiation on your skin; when the UV intensity reaches 5-6 levels, you can avoid the harm of the sun's radiation on your skin. UV intensity reaches 5-6 level, when going out must walk in the shade; UV up to 7-9 level, in the morning from 10 am to 4 pm this period of time it is best not to sunbathe on the beach site; when the UV index is greater than or equal to 10, you should try to avoid going out, because at this time the ultraviolet radiation is extremely injurious
The application aspects are as follows:Chemistry: paint curing, pigment curing, photolithography
Biology: sterilization
Instrumental analysis: ore, drugs, food analysis
Application: human health care irradiation, trapping and killing of pests, fume oxidation, photocatalytic enzymes (titanium dioxide)
★ Chemistry - photochemical
Unsaturated polyester UV curing coatings
Advantages: drying and curing time is very short
No volatile solvents, harmless
No heat curing
The paint does not need to be sealed and stored
★ Biological - Sterilization
Deoxyribonucleic Acid (DNA) in bacteria. The strongest peak of UV absorption of DNA, ribonucleic acid (RNA) and nuclear proteins is at 254-257nm.
When bacteria absorb UV, it causes DNA strand breaks, resulting in the rupture of cross-linking of nucleic acids and proteins,
killing the biological activity of nucleic acids and causing bacterial death.
Advantages: fast
Secondary pollution
Bactericidal efficiency of UV on common bacterial viruses (radiation intensity: 30000?W/cm2)
Killing object Seconds(S)*
Bacteria Anthrax Bacillus anthracis 0.3
Tetanus Bacillus 0.3
Dysentery bacillus 1.5
Escherichia coli 0.4
Staphylococcus spp. 1.3
Mycobacterium tuberculosis 0.4
Viruses Influenza virus 0.3
Poliovirus 0.8
Hepatitis B virus 0.8
Bacteriophage virus 0.2
Mold spores Aspergillus niger 0.3-6.7
Trichoderma spp. 4.6
Penicillium spp. 0.9-3.0
Algae Orchid green algae 10-40
Nematode eggs 3.4
Green algae 1.2
Protozoa 4.0-6.7
Fish diseases Leukoplakia 2.7
Infectious pancreatic necrosis 4
Viral hemorrhagic disease 1.6
Instrumental Analysis
A certain intensity and wavelength of ultraviolet light, irradiation of substances (some substances need to be added to the fluorescent dyes), the material elements will emit fluorescence (photoluminescence), according to the color of the fluorescent light, you can determine the content of the element. Such as lead, mercury and other heavy metals, pesticide residues, etc. can be detected in this way. The fluorescent lamp is the use of this principle.
★ Black light (ultraviolet lamp) to attract insects
Most of the compound eyes of insects are particularly sensitive to 365nm ultraviolet light, in the evening, light a UV lamp, as if the world of light for insects.
★ human health care irradiation
280 ~ 320nm of ultraviolet light is called health care ultraviolet.
After irradiating the skin, the 7-dehydroergot cholesterol in the skin, converted to vitamin D3 and D2, to prevent rickets and occupational diseases (miners, etc.).
There are already health-care UV lamps available on the market.
★ Oil smoke oxidation - photolysis oxidation technology
With ultraviolet light to change the molecular chain of its oil and grease, at the same time, this ultraviolet light reacts with the oxygen in the air and produces ozone, which will be cold combustion of the oil and grease molecules to generate carbon dioxide and water, and the organic matter in the oil and grease is photolysed and oxidized, and the odor is eliminated.
★ Photocatalytic enzyme (titanium dioxide)
In the building materials or household appliances material surface to add (or coating) a small amount of nanoscale titanium dioxide powder, in the process of use, can be adsorbed volatile organic compounds VOC (eg, formaldehyde, benzene, toluene, ethanol, chloroform, etc.), UV irradiation can be used to decompose these organic compounds.
infrared ray]
Infrared ray is one of the many invisible light in the sun's rays, by the German scientists H?sschel in 1800, also known as infrared radiation, he will be the sunlight with a prism to break down the position of a variety of different colors of color bands placed on the thermometer, attempting to measure the various colors of the light of the heating effect. It was found that the thermometer located on the outside of the red light heated up the fastest. Therefore, it was concluded that in the solar spectrum, there must be invisible light on the outside of red light, which is infrared light. This is infrared light, which can also be used as a transmission medium. The wavelength of infrared light on the solar spectrum is greater than that of visible light, with a wavelength of 0.75 to 1000 μm. Infrared light can be divided into three parts, namely, near-infrared, with a wavelength of 0.75 to 1.50 μm; mid-infrared, with a wavelength of 1.50 to 6.0 μm; far-infrared, with a wavelength of 6.0 to l000 μm between.
The real infrared night vision is photomultiplier tube imaging, and the principle of the telescope is completely different, can not be used during the day, expensive and need power to work.
Physical properties of infrared light
In the spectrum of wavelengths from 0.76 to 400 microns of a section called infrared, infrared is invisible light. All substances above absolute zero (-273°C) can produce infrared rays. Modern physics calls them heat rays. Medical infrared can be divided into two categories: near-infrared and far-infrared.
Near-infrared or short-wave infrared, wavelength 0.76 ~ 1.5 microns, penetrate into the human body tissue is deeper, about 5 ~ 10 mm; far-infrared or long-wave infrared, wavelength 1.5 ~ 400 microns, more than absorbed by the surface skin, the depth of penetration of the tissue is less than 2 mm.
Physiological and therapeutic effects of infrared rays
Reflection and absorption of infrared rays
After infrared radiation is irradiated on the body surface, part of it is reflected, and the other part is absorbed by the skin. The degree of skin reflection of infrared radiation is related to the condition of pigmentation, with a wavelength of 0.9 microns of infrared radiation, no pigmentation of the skin to reflect about 60% of its energy; and there is pigmentation of the skin to reflect about 40% of its energy. Long-wave infrared (wavelength 1.5 microns or more) irradiation, the vast majority of the reflected and absorbed by the superficial skin tissues, the depth of penetration of the skin is only up to 0.05 ~ 2 mm, and thus can only act on the skin's surface tissues; short-wave infrared (wavelength of 1.5 microns or less) as well as the red light of the near infrared part of the deepest infrared into the tissues, the depth of penetration of up to 10 millimeters, and can be directly effected by blood vessels in the skin, The infrared rays penetrate deepest into the tissues, penetrating up to 10 millimeters, and can directly affect the skin's blood vessels, lymphatic vessels, nerve endings and other subcutaneous tissues.
Infrared erythema
Infrared erythema can appear when sufficient intensity of infrared radiation is irradiated to the skin, and the erythema disappears soon after irradiation is stopped. Large doses of infrared light irradiation of the skin for many times, can produce brown marble-like pigmentation, which is related to the thermal effect of strengthening the vascular wall basal cell layer in the melanocyte pigment formation.
The therapeutic effect of infrared rays
The therapeutic effect of infrared rays is based on the warming effect. Under infrared irradiation, the tissue temperature rises, capillary expansion, blood flow accelerates, material metabolism is enhanced, and the vitality and regenerative capacity of tissue cells increases. When infrared light treats chronic inflammation, it improves blood circulation, increases the phagocytosis of cells, eliminates swelling and promotes the dissipation of inflammation. Infrared rays can reduce the excitability of the nervous system, have analgesic, relieve the spasm of transverse and smooth muscles as well as promote the recovery of nerve function. In the treatment of chronic infected wounds and chronic ulcers, it improves tissue nutrition, eliminates granulomatous edema, promotes granulomatous growth and accelerates wound healing. Infrared irradiation has the effect of reducing the exudation of burn wounds. Infrared light is also often used in the treatment of sprains and contusions, to promote tissue swelling and hematoma dissipation as well as reduce postoperative adhesions, promote scar softening, reduce scar contracture.
Infrared light on the role of the eye
As the eye contains more liquid, the infrared absorption is strong, and thus a certain intensity of infrared light directly irradiation of the eye can cause cataracts. The production of cataracts is related to the role of short-wave infrared; infrared wavelengths greater than 1.5 microns do not cause cataracts.
The role of the light bath on the body
The role of the light bath factors are infrared rays, visible light and hot air. Light bath can make a larger area, even the whole body sweating, thus reducing the burden on the kidneys, and can improve the blood circulation of the kidneys, which is conducive to the recovery of kidney function. Light bath action can increase hemoglobin, red blood cells, neutrophils, lymphocytes, eosinophils, and mild nuclear left shift; strengthen immunity. Localized baths can improve the blood supply and nutrition of nerves and muscles, thus promoting the return of their function to normal. Whole-body light bath can significantly affect the metabolic processes in the body and increase the burden of systemic thermal regulation; it also has a certain effect on the vegetative nervous system and cardiovascular system.
Equipment and therapeutic methods
Infrared light source
1. Infrared emitter
The resistance wire wrapped around the porcelain rod, the resistance wire after power generation heat production, so that the cover in the resistance wire outside the carbon rod temperature (generally not more than 500 ℃), the emission of long-wave infrared rays are mainly.
Infrared radiators have two types of standing and portable. Standing infrared emitter power up to 600 ~ 1000 watts or more.
In recent years, some areas of China made far-infrared radiators for medical use, for example, with high silica oxygen as a component, made of far-infrared radiators.
2. incandescent lamp
In the medical treatment of a variety of different power incandescent bulbs are widely used as infrared light source. The tungsten filament inside the bulb can reach a temperature of 2,000 to 2,500 degrees Celsius when energized.
Incandescent lamps are used in phototherapy in the following forms:
Floor-standing incandescent lamps: incandescent bulbs with a power of 250-1000W, in the reflector installed between a metal mesh, for protection. Ground-based incandescent lamps, usually called sun lamps.
Portable incandescent lamps: with less power (more than 200W or less) incandescent bulbs, installed in a small reflector, the reflector is fixed in a small bracket.
3. Light bath device
Can be localized or whole body irradiation with two kinds. According to the different sizes of the light bath box, installed in the box 40 ~ 60W bulb 6 ~ 30. Light bath box is semicircular, the fixed bulb part of the box can add a small metal reflector. Whole body light bath box should be attached to the thermometer, in order to observe the temperature inside the box, adjusted at any time.
Infrared therapy operation
1. The patient to take the appropriate position, bare irradiated parts.
2. Check whether the irradiation site is normal to the warmth.
3. Move the lamp to the top or side of the irradiation site, the distance is generally as follows:
Power 500W or more, the lamp distance should be more than 50-60cm; power 250-300W, the lamp distance of 30-40cm; power 200W or less, the lamp distance of about 20cm.
4. Application of local or whole-body light bath, the two ends of the light bath box need to be covered with a cloth sheet. Three to five minutes after the power is turned on, the patient should be asked whether the warmth is appropriate; the temperature in the light bath box should be maintained at 40 to 50 ℃.
5. Each irradiation 15 ~ 30 minutes, 1 ~ 2 times a day, 15 ~ 20 times for a course of treatment.
6. At the end of the treatment, dry the sweat on the irradiated area, and the patient should rest indoors for 10 to 15 minutes before going out.
[Attachment] Precautions
(1) The patient should not move the position during treatment to prevent burns.
(2) If you feel overheating, panic, dizziness and other reactions during the irradiation process, you need to inform the staff immediately.
(3) When the irradiation part is close to the eyes or the light can be shot to the eyes, the eyes should be covered with gauze.
(4) The affected area has warmth and heat sensation disorder or irradiation of the fresh scar site, implantation site, the application of small doses, and closely observe the local reaction to avoid burns.
(5) blood circulation obstacle parts, more obvious capillaries or vasodilatation parts generally do not use infrared irradiation.
Selection of irradiation mode and irradiation dose
1. Selection of different irradiation modes
Infrared irradiation is mainly used for local treatment, in individual cases, such as pediatric whole-body ultraviolet irradiation can also be used with the application of infrared radiation to do whole-body irradiation. Local irradiation, such as the need for deeper thermal effects, the preferred choice of incandescent lamps (i.e., sun lamps). Treatment of chronic rheumatoid arthritis can be localized light bath; treatment of multiple peripheral neuritis can be used whole body light bath.
2. irradiation dose to determine the size of the infrared therapy dose, mainly based on the characteristics of the lesion, site, patient age and functional status of the body. Infrared irradiation when the patient has a comfortable sense of warmth, the skin can appear light red uniform erythema, such as the appearance of marbled erythema is overheating performance. The skin temperature should not exceed 45℃, otherwise it can cause burns.
Main indications and contraindications
(I) Indications
Rheumatoid arthritis, chronic bronchitis, pleurisy, chronic gastritis, chronic enteritis, radiculitis, neuritis, polypoidal peripheral neuritis, spasmodic paralysis, flaccid paralysis, peripheral nerve trauma, soft-tissue trauma, chronic wounds, frostbite, burns, decubitus ulcers, chronic lymph node inflammation. Chronic phlebitis, post-injection sclerosis, postoperative adhesions, scar contracture, postpartum lack of milk, nipple fissure, vulvodynia, chronic pelvic inflammatory disease, eczema, neurodermatitis, skin ulcers and so on.
(2) Contraindications
Bleeding tendency, high fever, active tuberculosis, severe arteriosclerosis, occlusive vasculitis, etc.
[Attachment] Examples of prescriptions
(1) Infrared irradiation of both knee joints: lamp distance 40cm, 30 minutes, once a day, 7 times. Indications: chronic rheumatoid arthritis
(2) infrared irradiation of the right side of the thorax (lower half) lamp distance 50cm, 20 minutes, once a day, 8 times. Indications: right-sided dry pleurisy
(3) Sun lamp irradiation of the lumbosacral region: lamp distance 40cm, 20-30 minutes, once a day, 6 times. Indications: lumbosacral radiculitis
(4) Whole-body light bath: box temperature 40 to 45 ℃, 20 to 30 minutes, once a day, 8 times. Indications: multiple peripheral neuritis
(5) localized light bath of the left calf: 20 to 30 minutes, once a day, 8 times. Indications: left common peroneal nerve trauma
Infrared pollution
Infrared rays in recent years in the military, artificial satellites, and industry, health, scientific research and other aspects of the application of the increasingly wide range of infrared rays, and therefore infrared pollution problems have arisen. Infrared is a kind of thermal radiation, the human body can cause high-temperature damage. Stronger infrared rays can cause skin injuries similar to scalds, initially burning and then causing burns. Infrared damage to the eye has several different situations, the wavelength of 7500 ~ 13000 ? of infrared light on the cornea of the cornea of the higher transmittance rate, can cause damage to the retina of the fundus of the eye. Especially near 11000 ? infrared, can make the front of the eye medium (corneal crystal, etc.) is not damaged and directly caused by the fundus retinal burns. Infrared rays with a wavelength of 19,000? or more are almost completely absorbed by the cornea, causing corneal burns (clouding, white spots). Infrared energy with wavelength greater than 14000? is mostly absorbed by the cornea and intraocular fluid, and does not penetrate the iris. Only infrared rays with wavelengths below 13,000 angstroms can penetrate the iris and cause iris damage. If the human eye is exposed to infrared light for a long time, it may cause cataracts.
Infrared rays can be created by humans and are widely found in nature. All living things radiate infrared rays, and the macroscopic effect of infrared rays is heat.
We know that the cause of heat is the irregular motion of the particles that make up matter. This movement also radiates electromagnetic waves, most of which are infrared.
1. It is true that the sun's rays are almost absent at night, but all substances on earth radiate infrared rays, some strongly and some calmly. Infrared photography is through the reception of infrared rays emitted by various substances, and then show them, but it is not itself through the emission of infrared rays to take pictures.
2. Infrared vision and night vision are different properties of infrared light. The first night vision is because the human eye can not see infrared light, while the special design of the camera and night vision device is specialized in receiving infrared light. That's why it looks dark to us, but the camera picks it up. Because there is infrared light everywhere, infrared cameras and night vision devices are bright.
Perspective is the use of infrared wavelengths longer than visible light, can pass through some visible light can not pass through the fabric (such as mixed cotton and nylon), so through a certain selection of filtering, you can get these fabrics behind the image.