46results about How to "Improve loss performance" patented technology

The present invention provides a method and a system of packet communication queuing and selective pushout. In the packet communication module, the quasi-longest-queue pointer is set up to point to the quasi-longest queue within the shared buffer to implement selective pushout. When an in-coming packet enters its destination queue, or an out-going packets leaves one of the output queues, the quasi-longest-queue pointer is maintained by comparing the length of the quasi-longest queue and that of the destination or output queue, respectively. The longer one of the current quasi-longest queue and the length-varied queue becomes the new quasi-longest queue. In addition, a flag and a pointer are used to indicate the presence of a damaged upper-layer packet and the queue the damaged packet belongs to, respectively When the shared buffer is full and packet discarding is to be performed, the packet to be discarded is first selected from the queue storing the damaged upper-layer packet, and then, the quasi-longest queue. The present invention implements the selective pushout packet discarding discipline with significantly reduced number of queue length comparisons, and employs the upper-layer packet discarding control to achieve better upper layer packet loss performance.

The invention discloses a W-band even-order sub-harmonic mixer, which comprises a radio-frequency broadband band-pass filter, an anti-parallel diode pair, a phase adjusting transmission line, a local oscillator low-pass filter and a duplexer, wherein one end of the local oscillator low-pass filter is connected with a common port of the duplexer while the other end of the local oscillator low-pass filter is connected with the phase adjusting transmission line, and the anti-parallel diode pair is bridged between the radio-frequency broadband band-pass filter and the phase adjusting transmission line. The W-band even-order sub-harmonic mixer realizes mutual isolation of radio-frequency signals, local oscillator signals and intermediate frequency signals by means of the radio-frequency broadband band-pass filter, the local oscillator low-pass filter and the duplexer, and the mixer can realize wide operation bandwidth as the radio-frequency broadband band-pass filter, the local oscillator low-pass filter and the duplexer have wide bandwidth.

The invention discloses usage of manganese dioxide coated carbon particle dielectric materials as electromagnetic wave absorption materials and belongs to the technical field of wave absorption materials. A preparation method comprises the steps of adding carbon particles into a mixed solution and absolute ethyl alcohol for ultrasonic treatment, wherein the mixed solution is obtained by mixing sodium dodecyl benzene sulfonate and 10%-concentration diluted hydrochloric acid according to a mass ratio of 1 to 10; performing ultrasonic treatment for 2 hours in deionized water, adding potassium permanganate, subjecting manganese dioxide generated under the action of water bath to nucleation and growing on the surfaces of the carbon particles to form a manganese dioxide coated carbon composite structure. According to the usage, the preparation process is simple and easy to operate, and the manganese dioxide is coated evenly. The manganese dioxide coated carbon particle composite structure has outstanding conductive performance and a dielectric loss property, can be used as a dielectric loss medium and has good application prospects in the field of electromagnetic wave absorption materials.

The invention relates to a quick preparation method of a wave-absorbing ceramic-based composite material with an electromagnetic-impedance gradient matrix. The quick preparation method comprises the following steps of firstly adopting a CVI (Chemical Vapor Infiltration) or PIP (Polymer Infiltration and Pyrolysis) process to prepare a porous carbon-based composite material, then adopting an RMI (Reactive Melt infiltration) process to obtain a C-SiC-based composite material, finally adopting a nitriding process to transform residual Si in the composite material into Si3N4, and obtaining the wave-absorbing ceramic-based composite material, wherein the phase composition of the matrix is C, SiC and Si3N4 from inside to outside, and the matching property with electromagnetic impedance of a freespace is gradually improved; the phase composition of the matrix is Si3N4, SiC and C from outside to inside, and the loss capability to electromagnetic waves is gradually enhanced. The quick preparation method has the beneficial effects that the process controllability is strong, and compared with the CVI and PIP methods, the quick preparation method is short in preparation period and low in production cost. In the aspect of electromagnetic property of the composite material, the matching property of the matrix material with the impedance of the free space is gradually improved, the loss capability to the electromagnetic waves from outside to inside is gradually enhanced, so that the benefit to improving the wave-absorbing property of the composite material is achieved.

The invention relates to the technical field of microwave absorption composite materials, in particular to a structure and function integrated continuous fiber resin-based wave-absorbing stealth composite material and a preparation method thereof. The structure and function integrated continuous fiber resin-based wave-absorbing stealth composite material is formed by compounding a wave-transparent layer, a wave-absorbing layer and a reflecting layer in sequence. The upper wave-transparent layer can provide good impedance matching performance; the middle wave-absorbing layer can endow the composite material with strong electromagnetic wave loss capability by means of dielectric loss, magnetic loss, one fourth wavelength loss and multiple scattering and edge scattering among carbon fiber bundles through array staggered arrangement of multiple layers of the continuous carbon fiber bundles or cooperative use of the middle wave-absorbing layer and wave-absorbing functional particles; and the bottom reflecting layer can reflect electromagnetic waves and is secondarily lost, so that the electromagnetic wave absorption performance of the composite material is further improved. According to the structure and function integrated continuous fiber resin-based wave-absorbing stealth composite material and the preparation method thereof, raw materials are wide in source, the forming process is stable, operation is convenient and fast, and the prepared composite material is excellent in wave absorbing performance and mechanical performance and has good application prospects in the military and civil fields.

The invention discloses a high-order mode single-pulse antenna based on substrate integrated waveguide. A feed network, an upper layer medium base plate and a substrate integrated waveguide cavity aresequentially arranged from top to bottom. The feed network comprises a difference port network and a port network respectively arranged at two ends of an antenna; the substrate integrated waveguide cavity is divided into four independent symmetrical sub waveguide cavities through a first metal through hole in a shape like a Chinese character 'tian'; the difference port network and the port network respectively correspond to two sub waveguide cavities and respectively correspond to one row of second metal through holes; 180-degree phase differences are formed in the sub waveguide cavity corresponding to the difference port network, so that difference beams are obtained; and sum beams are obtained in the sub waveguide cavity corresponding to the port network. The single-pulse antenna provided by the invention has the advantages of simple structure, high radiation efficiency and low profile. The feed network design of the single-pulse antenna is greatly simplified.

The invention discloses a composite material based on lignocellulose and bacterial cellulose as well as a preparation method and application of the composite material, and belongs to the technical field of biomass cellulose materials. The method comprises the steps of adding wood chips into a mixed solution of sodium chlorite and glacial acetic acid for pretreatment, and performing sterilization treatment to obtain sterilized delignified wood chips; preliminarily forming a bacterial cellulose film by adopting static culture, paving the sterilized delignified wood chips on the surface of the preliminarily formed bacterial cellulose film, and continuing standing fermentation culture to obtain a lignocellulose-bacterial cellulose composite material; and carbonizing at high temperature to obtain a carbon fiber composite material. The raw materials used in the preparation method are all from natural renewable biomass materials, so that the preparation method has the characteristics of low raw material cost, simple technical method and the like; and complementation of the plant fibers and the bacterial fibers in spatial orientation is achieved, and the material has high electromagnetic wave absorption capacity.

Disclosed are a terahertz signal generation apparatus and a terahertz signal generation method using the same. The terahertz signal generation apparatus includes first and second resonators configured to respectively output an optical signal of a first resonant frequency and an optical signal of a second resonant frequency from an optical signal input through a gain medium, an optical modulator configured to optically modulate the output optical signal of the second resonant frequency, an optical combiner configured to combine the CW optical signal of the first resonant frequency and the modulated optical signal of the second resonant frequency, and a signal generator configured to generate a terahertz signal using heterodyne beating between the CW optical signal of the first resonant frequency and the modulated optical signal of the second resonant frequency, wherein the first resonant frequency and the second resonant frequency are processed to have a predetermined frequency difference.

The invention discloses a high-frequency high-magnetic-field low-loss manganese-zinc ferrite material and a preparation method thereof. The high-frequency high-magnetic-field low-loss manganese-zinc ferrite material is prepared from a main component and an additive. The main component comprises the following components in percentage by mole: 53-55% of Fe2O3, 39-43% of MnO and 4-6% of ZnO; and the additive comprises Co3O4 and TiO2. The preparation method comprises the following steps: (1) burdening and sanding; (2) pre-sintering; (3) carrying out secondary sanding; (4) granulating and forming; and (5) sintering, namely sintering a blank at the temperature of 1,200 to 1,250 DEG C under the condition that the oxygen partial pressure is controlled to be 3-5 vol% to obtain the high-frequency high-magnetic-field low-loss manganese-zinc ferrite material. According to the invention, through formula development, trace element modification and improvement of the preparation method, the loss of the high-frequency high-magnetic-field manganese-zinc ferrite at high temperature is reduced.

The invention discloses an iron-silicon composite magnetic powder core with a surface coating structure and a preparation method of the iron-silicon composite magnetic powder core. The method comprises the steps of dropwise adding a silane coupling agent into iron-silicon composite magnetic powder dispersed with absolute ethyl alcohol, conducting surface activation on the iron-silicon composite magnetic powder for 1-2 h, then slowing dropwise adding an alkaline solution, then slowing dropwise adding silicate ester, and carrying out surface modification on the activated iron-silicon composite magnetic powder by using the silicate ester to obtain the SiO2-coated iron-silicon composite magnetic powder core. The iron-silicon composite magnetic powder core with the surface coating structure prepared by the method is low in raw material cost, and the preparation process is clean and environment-friendly by adopting a chemical coating method. The coated composite magnetic powder core particles are insulated, so that the loss can be reduced under the condition of keeping the high frequency of the magnetic powder core, the service life is prolonged, and finally, the composite magnetic powder core can be widely applied in the high-frequency and high-power application fields.

The invention is suitable for the technical field of wireless communication. The invention discloses a flexible metasurface film capable of reducing an SAR value. The film comprises a wave-absorbing metal structure layer and a base material fixed with the wave-absorbing metal structure layer in sequence, and the wave absorbing metal structure layer is provided with a periodic resonance unit. When electromagnetic waves are incident to the periodic resonance unit, the electromagnetic response generated by the periodic resonance unit generates a new electromagnetic loss. Due to the special electromagnetic characteristic of absorbing the electromagnetic waves, incident waves completely enter the periodic resonance unit, the loss effect of the interior of the wave absorbing metal structure layer on the electromagnetic waves is improved, energy is completely consumed in the wave absorbing metal structure layer, a reflection coefficient and a transmission coefficient are both 0, wave absorption is achieved, and an SAR peak value is effectively reduced. By adjusting the size of the periodic resonance unit and the interval between the periodic resonance units, the SAR value absorption of different frequency bands can be realized, the contradiction between the radiation index of the antenna and the SAR peak value is avoided, and the film can be widely applied to 5G terminal products.

The present invention solves the problem of providing a rubber composition for anti-vibration rubber which has excellent high loss properties and maintains a good low dynamic amplification ratio. In order to solve this problem, the present invention is characterized by comprising: a rubber component containing a diene rubber; carbon black of greater than 0 parts by mass and 10 parts by mass or less with respect to 100 parts by mass of the rubber component; and with respect to 100 parts by mass of The rubber component is 50-70 parts by mass of oil.

The invention provides a current interruption characteristic optimization circuit of a current injection type DC circuit breaker. The optimization circuit comprises a vacuum switch, a discharge branchcircuit and an LC resonance branch circuit, wherein the LC resonance branch circuit is connected with the vacuum switch in parallel, the discharge branch circuit is connected with a capacitor of theLC resonance branch circuit in parallel, and the capacitor of the LC resonance branch circuit realizes the discharge voltage reduction during the low current interruption process of the DC circuit breaker through the discharge branch circuit. The optimization circuit not only improves the low current interruption characteristic under the premise of maintaining the high fault current interruption characteristic, but also avoids the increased equipment complexity, high loss and low reliability caused by a series saturable reactor in the prior art at the same time. Meanwhile, the invention can further omit a buffer branch circuit structure of the novel current injection type DC circuit breaker at present, and greatly increases the equipment reliability.

Provided is a compact waveguide termination including: a waveguide, a termination coupled with the waveguide and formed with a groove, and a thin film resistor part coupled with the groove and configured to attenuate an input signal at a central region of the waveguide, thereby improving frequency performance.

The invention discloses a polypyrrole coated ferroferric oxide nanoflower wave-absorbing material as well as a preparation method and application thereof. The preparation method comprises the following steps: dissolving an inorganic trivalent iron salt in an organic alcohol solvent, adding an alkaline substance to obtain a mixed solution, heating the mixed solution to 160-200 DEG C, and keeping the temperature for 2-6 hours to obtain a precursor with a hierarchical nanoflower structure; the precursor is subjected to calcination treatment, and ferroferric oxide with a hierarchical nanoflower structure is obtained; the ferroferric oxide is dispersed in deionized water, pyrrole is added, then an oxidizing agent is added, pyrrole cation free radicals are subjected to coupling polymerization along the surface of the ultrathin sheet, and the polypyrrole-coated ferroferric oxide nanoflower wave-absorbing material is obtained. The ferroferric oxide with the hierarchical nanoflower structure is coated with the in-situ polymerized polypyrrole, impedance matching is improved, more incident electromagnetic waves are captured, multiple reflection and scattering of the electromagnetic waves in the composite material are promoted, the transmission path of the electromagnetic waves is prolonged, and the loss capacity of the electromagnetic waves is enhanced.

The invention relates to a high-temperature-resistant transition metal high-entropy oxide wave-absorbing filler and a preparation method thereof. The composition of the high-temperature-resistant transition metal high-entropy oxide wave-absorbing filler is (1) a spinel structure (Fea/(4+a)Co1/(4+a)Ni1/(4+a)Cr1/(4+a)Mn1/(4+a))3O4, wherein a is greater than or equal to 1 and less than or equal to 3.5; or (2) a corundum-type structure ((Feb/(4+b)Co1/(4+b)Ni1/(4+b)Cr1/(4+b)Mn1/(4+b))2O3, wherein 5 < = b < = 6; or a combination of (1) + (2).

The invention discloses a yarn-based threading needle block hot-pressing rolling online stain removing machine. The machine structurally comprises an industrial control panel, a power distribution box, a hot-pressing needle block inner groove, a nonwoven fabric guide belt, a motor framework, a start and stop battery box and a bottom rod supporting frame base. According to the machine, the effect that sliding block cloth needles which are inserted and threaded through a stain-removing needle tube are dropped for sliding and removing is achieved through cooperation of the hot-pressing needle block inner groove and the nonwoven fabric guide belt; a hot tube pressing frame arm achieves the effect of hot-pressing loose and soft yarn through an electrical heating tube, convenience is brought tocooperative operation of thermization on seams among internal yarn of nonwoven fabric and needle liquid removal, droplet holes are distributed in the whole tube wall of the needle tube, and yarn sliding hook laying and alcohol washing on the overall nonwoven fabric are improved; and then the hot tube pressing frame arm is lifted in cooperation with a lifting arm sliding column block to remove stains one by one from left to right, the effect of uniform carpet-like fine processing on the surface of the nonwoven fabric is achieved, the loss of stain removal is lowered, the efficiency of needle threading is achieved, and the neatness of yarn clearance of the nonwoven fabric is improved.