What Is Microwave Digestion?

Microwave refers to electromagnetic waves with a frequency of 300MHz-300GHz. It is an abbreviation for a limited frequency band in radio waves, that is, electromagnetic waves with a wavelength between 1 millimeter and 1 meter. The microwave frequency is higher than the average radio wave frequency, and is often called "ultra-high frequency electromagnetic waves". Microwave as an electromagnetic wave also has wave-particle duality. The basic properties of microwaves are generally three characteristics: transmission, reflection, and absorption. For glass, plastic, and porcelain, microwaves pass through almost without being absorbed. For water and food, it absorbs microwaves and heats itself. For metallic things, microwaves are reflected.

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Microwave refers to electromagnetic waves with a frequency of 300MHz-300GHz. It is an abbreviation for a limited frequency band in radio waves, that is, electromagnetic waves with a wavelength between 1 millimeter and 1 meter. The microwave frequency is higher than the average radio wave frequency, and is often called "ultra-high frequency electromagnetic waves". Microwave as an electromagnetic wave also has wave-particle duality. The basic properties of microwaves are generally three characteristics: transmission, reflection, and absorption. For glass, plastic, and porcelain, microwaves pass through almost without being absorbed. For water and food, it absorbs microwaves and heats itself. For metallic things, microwaves are reflected.

Microwave transmission meets optical principles, linear propagation

Chinese name

microwave

Foreign name

Microwave

Pinyin

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Zhuyin

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1. Tiny waves. Han Liu Xiang's "New Preface · Miscellaneous II": "Introducing fiber, raising microwaves, breaking the wind." Tang Xuhun's "Pan Wuyunxi" poem: "Axe screaming axles, microwave fishing rods." Song Zhuxi The poem "Xiqing": "The Gao Liu is impulse, and the water simmers in the microwave." Jun Qing, "Futurism and Sea Niangniang": "Every sunny morning or a quiet moonlight, the sea is calm and the waves are unpopular."

2. Still aftermath. Han Sima Xiangru's "Feng Chanwen": "Every time you have a clear stream, raise the microwave, the sound of Ying Ying, Tengmao Shi." Liang Qiao in the Southern Dynasties "Poetry" Volume: "Yongjia, noble and old, slightly unreal Talk. In the time of the article, I have ignored the words, faintly tasted, and the Jiang table, the microwave is still spreading. "Volume " preface of the shelter Lu Cong Zhi> ":" Jing Cong Zhi and stand up, I am interested in microwave."

3. Refers to women's eye waves. The Three Kingdoms Wei Caozhi's "Luo Shen Fu": "The unscrupulous media used to meet the joys and talked about the microwave." Qing Huang Zunxian's "Dongge Song": "Some people pass the microwave, and the lotus! Let me feed me with green Snail, lotus, lotus! "Gao Xu's poem" Shen Xiaoze for Gift ":" The beautiful lady leaves a movie, and is willing to put her mind in the microwave. "

4. Physics nouns. Refers to short-wavelength electromagnetic waves. Such as:

The frequency of microwave is between 300MHz-300GHz (0.3THz), and the wavelength is between 1m (excluding 1m) and 0.1cm. It is a collective term for decimeter wave, centimeter wave, millimeter wave and sub-millimeter wave. Microwave frequencies are higher than ordinary radio waves, and are often referred to as "UHF radio waves." Microwave as an electromagnetic wave also has wave-particle duality. The energy of the microwave quantum is 1 99 × l0 ^-25 to 1.99 × 10 ^-21 joules.

The basic properties of microwaves are generally three characteristics: transmission, reflection, and absorption. For glass, plastic, and porcelain, microwaves pass through almost without being absorbed. For water and food, it absorbs microwaves and heats itself. For metallic things, microwaves are reflected.

From the point of view of electronics and physics, the electromagnetic spectrum of microwave has the following important characteristics that are different from other wavebands:

Penetrability

Microwave is more than other electromagnetic waves used for radiant heating, such as

Microwave energy is usually caused by

Use micro

Microwave pair

The non-thermal effect of microwaves refers to other effects besides thermal effects, such as electrical effects, magnetic effects, and chemical effects. Under the action of the microwave electromagnetic field, some molecules in the organism will deform and vibrate, which will affect the function of the cell membrane, change the electrical state of the liquid inside and outside the cell membrane, cause changes in biological effects, and then affect the center

Microwaves have frequencies between 300MHz and 300GHz

Microwaves are electromagnetic waves with a wavelength of about 1m ~ 0.1mm (corresponding frequency is about 300MHz to 0.3THz). This electromagnetic spectrum includes decimeter waves, centimeters

24GHZ radar sensor

Wave, millimeter wave and sub-millimeter wave band. In radar and conventional microwave technology, the Latin alphabetic codes are often used to indicate finer band divisions.

The above is a conventional convention regarding the wavelength or frequency range of microwaves. From the perspective of the development of modern microwave technology, it is generally considered that electromagnetic waves shorter than 1 mm (that is, sub-millimeter waves) belong to the microwave range, and are an important area of modern microwave research.

From the point of view of electronics and physics, the electromagnetic spectrum of microwaves has some characteristics that are different from other wavebands. Microwaves are characterized by electronics in that their wavelengths are much smaller than many objects on Earth and commonly used in laboratories, or at the same order of magnitude. This is different from ordinary radio waves that people are already familiar with, because the wavelength of ordinary radio waves is much larger than the size of ordinary objects on the earth. When the wavelength is much smaller than the size of objects (such as airplanes, ships, rockets, buildings, etc.), the characteristics of microwaves are similar to geometric optics. With this feature, a highly directional system (such as a parabolic reflector) can be made in the microwave band. When the wavelength and the size of objects (such as radio equipment in the laboratory) have the same order of magnitude, the characteristics of microwave are similar to those of sound waves. Flute; resonant cavity is similar to resonance box and so on. The characteristics of wavelength and object size in the same order provide a series of typical electromagnetic field boundary value problems.

In physics, many resonance phenomena exhibited by molecules, atoms and nuclear systems occur in the range of microwaves, so microwaves provide an effective research means for exploring the basic characteristics of matter.

Due to these characteristics, a series of technologies such as microwave generation, amplification, transmission, reception, transmission, control, and measurement are different from other wavebands (see microwave tube, microwave measurement, etc.).

Microwaves became a technological science, beginning in the 1930s. The formation of microwave technology is marked by the practical application of waveguides. The invention of several forms of microwave electron tubes (klystrons, magnetrons, traveling wave tubes, etc.) is another sign.

In the Second World War, microwave technology was developed by leaps and bounds. Because of the need for war, the focus of microwave research was on radar, which led to the

Microwave sensor

Research and development of wave components and devices, high-power microwave tubes, microwave circuits, and microwave measurement technologies. So far, microwave technology has become a discipline that is quite mature both in theory and technology, and is a discipline that continues to develop in depth.

The solidification of microwave oscillation source and the integration of microwave system are two important directions for the development of modern microwave technology. Advances in solid-state microwave devices in terms of power and frequency have made conventional microwave electron tubes in many microwave systems replaced or to be replaced by solid-state sources. The development of solid-state microwave sources has also promoted the research of microwave integrated circuits.

The continuous advancement of frequencies to higher ranges is still a major trend in microwave research and development. The research and development of lasers in the 1960s have crossed the gap between sub-millimeter waves and infrared and penetrated into the electromagnetic spectrum of visible light. Using conventional microwave technology and quantum electronics, it has been possible to generate radiant power in the entire electromagnetic spectrum from microwave to light. However, at certain frequencies and bands in the millimeter wave-infrared gap, coherent radiant power sufficient for practical systems has not been obtained.

The development of microwave is also reflected in the expansion of the scope of application. The most important applications of microwaves are radar and communications. Radar is not only used in national defense, but also used in navigation, meteorological survey, geodetic survey, industrial inspection and traffic management. Communication applications are mainly modern satellite communications and conventional relay communications. Radio telescopes and microwave accelerators are of great significance to the research of physics and astronomy. Millimeter-wave microwave technology provides an effective method for controlling plasma measurements of thermonuclear reactions. Microwave remote sensing has become an important method for studying celestial bodies, meteorology and geodesy, and resource exploration. The research of microwave in industrial production, agricultural science, etc., as well as the research and development of microwave in biology, medicine, etc. have been paid more and more attention (see microwave applications, microwave energy applications, microwave medical applications, etc.).

Microwaves and other disciplines interpenetrate to form a number of important marginal disciplines, such as microwave astronomy, microwave meteorology, microwave spectroscopy, quantum electrodynamics, microwave semiconductor electronics, and microwave superconductivity. The research and application of microwave acoustics has become an active field. The development of microwave optics, especially the development of fiber optic technology since the 1970s, has the significance of technological change (see microwave and radio frequency spectroscopy).

Commonly used wireless transmission media are microwave, laser, and infrared. Communication media are also called transmission media and are used to connect network devices in computer networks. Transmission media can be generally divided into wired transmission media and wireless transmission media!

In theory, microwaves can act as a weapon that can strike any electronic system and paralyze cars, aircraft and nuclear power plants. In addition, microwave weapons can cause a burning sensation without causing casualties and can be used to disperse people. ^[1]

Transmitter mounted on a control waveguide. The waveguide structure in the electromagnet applicator (cavity) comes from energy coupling. The reflected electromagnetic energy is a heating product that depends on the size of the cavity and the dielectric heating. By using a tuner, the amount of reflected electromagnetic energy can be minimized to improve efficiency optimally.