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800 results about "Microwave technology" patented technology

Apparatus of generating microwave phase coding signals in an optical manner

InactiveCN105162523AWide frequency adjustable rangeLarge time-bandwidth productPhase-modulated carrier systemsElectromagnetic transmissionOptical communicationFrequency shift
The invention discloses an apparatus of generating microwave phase coding signals in an optical manner, and relates to the microwave technology field and the optical communication technology field. The apparatus is mainly applied to generating pulse compression signals in pulse compression radar. By means of the frequency shift characteristics of two parallel Mach-Zehnder modulators, the optical wavelength modulated by coding signals and the optical wavelength after a frequency shift are coupled to each other and then are detected through a photoelectric detector, in this way, phase coding microwave signals can be generated. The apparatus can produce binary, quaternary or multi-nary phase coding microwave signals. The generated phase coding microwave signals are wide in frequency adjustable scope, and have a great time-bandwidth product. A conventional phase coding microwave signal generation mode in the electric field is restricted by the bottleneck of the rate and the bandwidth of an electronic device, and the cost of generation of high frequency signals is extremely high or high frequency signals cannot be produced, the time-bandwidth product is limited, the reconstructiblity and the frequency adjustability of a system are poor, etc. The apparatus of the invention helps to overcome the above problems.
Owner:XIDIAN UNIV

Method for preparing resistant starch employing microwave technology

The invention belongs to the field of deep processing of starch, and particularly relates to a method for preparing resistant starch employing a microwave technology. The method is characterized by comprising the following steps: (1) preparing a starch emulsion from raw starch, and pregelatinizing the starch by virtue of microwave; (2) carrying out autoclaving treatment on the pregelatinized material at proper temperature and pressure, cooling materials, and hydrolyzing the starch with heat-resistant alpha-amylase and pullulanase until the chain length is 20-120DP; (3) paving the material on a flat plate, storing at 4 DEG C for 3-5 hours, heating the material to 30-50 DEG C by virtue of the microwave, cooling to a room temperature, repeating the temperature circulating process for 2-4 times until the moisture content of the starch is smaller than 14%, crushing and sieving to obtain resistant starch A; and (4) adding water to the resistant starch A, carrying out thermal treatment, adjusting the pH to be 1.5-2, carrying out oscillating reaction, adjusting the pH to be 7-8, adding pancreatin for enzymolysis, filtering and drying a filter cake by airflow until the moisture content is smaller than 14%, and crushing and sieving through a 100-mesh sieve, so as to obtain high-purity resistant starch B.
Owner:HUAZHONG AGRI UNIV

Method and device for preparing low-tar combustible gas through biomass gasification

ActiveCN101906323AHigh cracking rateMake up for the problem of low conduction rateGranular/pulverulent flues gasificationFixed bedCombustible gas
The invention discloses a method and a device for preparing a low-tar combustible gas through biomass gasification. The method comprises the followings steps of: pulverizing and gasifying biomass, and rapidly separating obtained gasification gas products and biomass char; heating and activating the biomass char in a microwave field; catalytically cracking tar in the gasification gas products by introducing the gasification gas products to pass through a treated biomass char layer, and carrying out secondary reaction on the gasification gas and the biomass char to produce the combustible gas. The device comprises a spiral-flow gasifier 1, a fixed bed reactor 2 and a microwave generator 3 which are connected through ducts, and the middle part of the fixed bed reactor is connected with the microwave generator 3 through a microwave duct 11. The microwave technology is applied to tar cracking, so that the problem of low heat transfer speed due to porous and loose biomass char is solved. Meanwhile, the cracking rate of tar and the secondary reaction activity between the char and the gasification gas are increased by using the 'hot spot effect' of microwaves. The device has the advantages of strong adaptability, simple and compact structure and easy enlargement.
Owner:GUANGZHOU INST OF ENERGY CONVERSION - CHINESE ACAD OF SCI

Microwave photonic zero-intermediate-frequency receiving device and method

The invention discloses a microwave photonic zero-intermediate-frequency receiving device and method. The method relates to the technical field of microwave and the technical field of optical communication. The method is as shown in the drawings. The device comprises a laser (LD), a polarization multiplexing Mach-Zehnder modulator (PDM-MZM), an erbium-doped optical fibre amplifier (EDFA), a wavelength division multiplexer (WDM), polarization controllers (PCs), a polarization beam splitter (PBS) and balance photoelectric detectors (BPDs). Modulation and polarization multiplexing of radio-frequency (RF) and local oscillator (LO) signals are carried out by utilization of the PDM-MZM; the WDM separates upper and lower optical sidebands; the PCs are respectively utilized for adjusting the polarization states of optical signals; and finally, the two BPDs respectively output I-channel and Q-channel baseband signals. By means of the microwave photonic zero-intermediate-frequency receiving device and method disclosed by the invention, zero-intermediate-frequency receiving is realized through a photonic method; the electronic bottleneck in the traditional electric field technology can be overcome; and the microwave photonic zero-intermediate-frequency receiving device has the advantages of being wide in working band, high in IQ balance degree, inhibited in direct-current offset and even-order distortion, electromagnetic-interference-resistant and the like.
Owner:XIDIAN UNIV

Process method for quickly preparing soybean antioxidant peptide

The invention discloses a process method for quickly preparing a soybean antioxidant peptide, belonging to the technical fields of deep processing of agricultural and sideline products and comprehensive utilization of byproducts thereof, and relating to the process method for quickly preparing the soybean antioxidant peptide by using a microwave technology. According to the process method, soybean protein concentrate powder with protein content of 70 percent is used as a raw material, the material passes through a microwave extractor through processes of preparing the soybean protein concentrate powder, pretreating soybean protein concentrate powder emulsion, performing microwave auxiliary enzymatic treatment on the soybean protein concentrate powder emulsion, deactivating enzymatic hydrolysate, centrifuging, performing ultrafiltration treatment and performing vacuum freeze drying treatment by using the microwave auxiliary enzymatic hydrolysis technology; the enzymatic hydrolysis time is shortened to 35-38 minutes; and compared with the conventional enzymatic hydrolysis, the efficiency is increased by 3-4 times, and the ABTS (2, 2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid)) free radical clear rate is over 72 percent and is equivalent to that of the conventional enzyme. According to the process method, a new idea is provided for technical research for quickly preparing the soybean antioxidant peptide, and a new approach is provided for development and application of soybean series products of high antioxidant activity.
Owner:JILIN UNIV

Dual-band wave absorption frequency selective surface system, design method and aircraft

The invention belongs to the technical field of a microwave technology and an aircraft stealth technology, and discloses a dual-band wave absorption frequency selective surface system, a design methodand an aircraft. The dual-band wave absorption frequency selective surface system is provided with a dielectric support plate, resistant thin film square rings and a circular-groove frequency selective surface, wherein the resistant thin film square rings are periodically arranged on an upper surface of the dielectric support plate, the circular-groove frequency selective surface is arranged on alower surface of the dielectric support plate and comprises a dielectric plate and a metal layer, the metal layer is arranged on an upper surface of the dielectric plate, the thickness of the metal layer is not considered, and circular grooves are periodically formed in the metal layer. By the dual-band wave absorption frequency selective surface system, k-band wave transparent/dual-band wave absorption can be achieved, an array pattern is compact, and good stability is achieved under an oblique incidence condition; the dual-band wave absorption frequency selective surface system is simple instructure; compared with a multi-layer structure, the dual-band wave absorption frequency selective surface system is only provided with the upper-layer resistant film, the intermediate-layer dielectric support plate and the lower-layer frequency selective surface, and is lighter and is lower in profile; and a transition band between the wave transparent band and the wave absorption band is small, and the wave absorption effect is good.
Owner:XIDIAN UNIV

A method for realizing microwave signal photonics frequency conversion and multi-channel phase shift by using a dual-polarization quadrature phase shift keying modulator

The invention discloses a method for realizing photonic frequency conversion and multi-channel phase shift of a microwave signal by using a dual-polarization quadrature phase shift keying (DP-QPSK) modulator, relates to the technical field of microwaves and the technical field of optical communication, and can be mainly applied to beam forming, IQ demodulation and the like of the signal. As shownin an attached drawing, the scheme comprises a light source, a local oscillation source, an erbium-doped optical fiber amplifier, an optical splitter, a polarization controller, a polarizer and a photoelectric detector. According to the invention, the DP-QPSK modulator is used for carrying out modulation and polarization multiplexing on a radio frequency signal and a microwave local oscillator, after light amplification, power is divided into multiple paths, each path controls the amplitude and phase of an output signal through the polarization controller and the polarizer, and finally a phase-changed intermediate frequency signal is obtained through the photoelectric detector. According to the invention, the up-down frequency conversion and phase shift functions of signals can be realizedat the same time, the influence caused by periodic power fading is avoided, the system gain is large, and the system has the characteristics of simple structure, flexible tuning, large bandwidth, multiple functions and the like.
Owner:XIDIAN UNIV

Relativistic backward-wave oscillator with collector shaped as Chinese character chang

The present invention relates to a microwave source of the high-power microwave technology field, and provides a relativistic backward-wave oscillator with a collector shaped as a Chinese character chang. The relativistic backward-wave oscillator comprises a cathode base, a cathode, an anode outer cylinder, a cut-off neck, a slow wave structure, a tapered waveguide, a reflector, an output waveguide and a solenoidal magnetic field. The collector shaped as the Chinese character chang is arranged behind the tapered waveguide, a stepped reflection cavity is arranged between the cut-off neck and the slow wave structure, and double extraction cavities are also arranged between the tail end of the slow wave structure and the tapered waveguide. The relativistic backward-wave oscillator of the present invention overcomes the disadvantage that the conventional relativistic backward-wave oscillator is difficult to consider the long output microwave pulse width and the high power conversion efficiency simultaneously, solves the problem that a coaxial extraction structure is easy to generate the plasmas to thereby influence the working efficiency, and realizes the microwave output that the pulse width is greater than 100 ns, the efficiency is greater than 40%, and the power is 6 GW, on the condition of using less slow wave blades. Moreover, a high-power microwave source is compact in structure, and is easy for the repeated frequency operation.
Owner:NAT UNIV OF DEFENSE TECH

Method for self-coherence detection of optical carrier radio frequency link based on polarization multiplexing

The invention discloses a method for self-coherence detection of an optical carrier radio frequency link based on polarization multiplexing. The invention relates to the technical field of optical communication and microwaves. The method is shown in the attached drawing, and comprises a laser source, a vector signal source, a polarization controller, a polarization beam splitter, a polarization multiplexing Mach-Zehnder modulator, a single-mode fiber, an erbium-doped fiber amplifier, a 90-degree optical coupler and a balance photoelectric detector. According to the method, two paths of different radio frequency electric signals are used for respectively carrying out intensity modulation and phase modulation on two optical carriers with orthogonal polarization states in a polarization multiplexing Mach-Zehnder modulator; frequency mixing is carried out through a 90-degree optical coupler; signal processing is performed on the electric signal output by the balance photoelectric detectorto recover an original electric signal; the polarization multiplexing mode is used for improving the utilization rate of spectrum and light source power; self-coherent detection is used at the receiving end; and a local oscillation light source and a complex phase noise elimination algorithm are avoided, so that the system cost is reduced, and the requirement for the line width of the laser is lowered.
Owner:XIDIAN UNIV

Ga2O3 Schottky diode device structure and manufacturing method thereof

The invention discloses a Ga2O3 Schottky diode device structure and a manufacturing method thereof, and mainly aims at solving the problems that a present Schottky diode device is low in reverse breakdown voltage and the parasitic capacitance in a field plate structure is high. The Ga2O3 Schottky diode device structure comprises a cathode electrode, a heavily-doped n type Ga2O3 substrate, a low-doped n type Ga2O3 epitaxial layer and an anode electrode from bottom to top; Schottky contact is formed in the part where the anode makes contact with the epitaxial layer, the cathode and the substrate make ohmic contact, grooves are distributed separately in the low-doped n type Ga2O3 epitaxial layer, intervals of grooves are increased progressively within the range of 0.3 to 0.5 micron, the first groove is positioned below the edge of the anode, the distance between the last groove and the first groove ranges from 10 to 15 micron, and AlGaO layers in which the Al component is greater than 20% are grown in an epitaxial manner in the grooves respectively. Thus, the reverse breakdown voltage is improved, the parasitic capacitance is reduced, positive characteristic is kept unchanged, and the structure and manufacturing method thereof can be used for high-speed integration circuits and microwave technologies.
Owner:XIDIAN UNIV

System and method for free-space method dielectric constant measurement through addition of polarization grid

InactiveCN107202942AReduce the impactReduce back-and-forth reflectionsTesting dielectric strengthDielectricComputational physics
The present invention discloses a system and method for free-space method dielectric constant measurement through addition of a polarization grid, belonging to the electromagnetic field and microwave technology field. On the basis of the current free-space method measurement system, a polarization grid mesh is added next to one side of a sample to be measured, a changing curve of reflection parameters and transmission parameters of the network with the angle of the polarization grid mesh is measured to distinguish the electromagnetic wave penetrating into the electromagnetic wave of the grid mesh from the invariable electromagnetic waves of other paths; and the changing signals carry the dielectric information of the sample to be measured, and the coefficients such as the amplitude in the changing curve are employed to perform evolution of the dielectric constant of the sample to be measured. In a stable environment, the changing of the network parameters with the polarization grid angle is not sensitive to the electromagnetic environment, and therefore the influences of the electromagnetic wave diffraction and diffraction in the experiment environment is effectively reduced. Besides, focusing lens antennas employ lossy material polylactic acid (PLA) to effectively reduce the multiple reflection of electromagnetic wave between the antennas to allow an experiment result to be more accurate.
Owner:BEIHANG UNIV

Low permeability coal seam electricity explosion vibration and microwave assisting liquid nitrogen freeze-thawing permeability increasing device and method

PendingCN108361061AIncreased number of riftsEasy to crackFluid removalGas removalFreeze thawingPorosity
The invention provides a low permeability coal seam electricity explosion vibration and microwave assisting liquid nitrogen freeze-thawing permeability increasing device. The low permeability coal seam electricity explosion vibration and microwave assisting liquid nitrogen freeze-thawing permeability increasing device comprises a pulse discharging reactor, a cable, a high voltage pulse generator,a fracturing pipe, a mining pipe, a high pressure rubber pipe, a microwave transmitter, a coaxial waveguide, a microwave converter, a microwave generator, a first hole packer, a second hole packer, anitrogen inflating pipe, a water box, a high pressure water pump, a liquid nitrogen pump and a liquid nitrogen tank. The invention further discloses a low permeability coal seam electricity explosionvibration and microwave assisting liquid nitrogen freeze-thawing permeability increasing method. A hydraulic fracturing technology, an electricity explosion vibration technology, a liquid nitrogen freeze-thawing technology and a microwave technology are harmoniously integrated, the permeability and the porosity of a coal seam are increased to a great extent, coal seam fractures can be increased, the liquid nitrogen freeze-thawing efficiency is improved, circular work is conducted, ice in the fractures is easily molten, the permeability of a low-permeability coal seam is greatly improved, the effect of mining and exhausting methane gas is improved, expected time needed for mining the methane gas is shortened by a large margin, and a superior premise is provided for mining the methane gas ofa mine.
Owner:HENAN POLYTECHNIC UNIV
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