32results about How to "High structural symmetry" patented technology

The invention discloses a wideband rotating magnetic characteristic measuring system and method based on a flexible excitation coil. The measuring system comprises a detection device, a digital signal processing unit, a power amplifier, and a differential amplification circuit. The digital signal processing unit is connected with the power amplifier and the differential amplification circuit. The detection device is connected with the power amplifier and the differential amplification circuit. The detection device comprises a three-stage frustum-shaped excitation winding, a sample holder, a horizontal structure magnetic ring, a center pillar, a buckle, a corner pillar and a base. The excitation winding of the measuring system is designed as a multi-stage frustum-shaped structure to realize a wideband magnetic characteristic test. The measuring method comprises first giving an excitation signal with a low frequency, gradually increasing the frequency of the excitation signal until the sample is saturated; replacing the excitation winding connection mode after the sample is completely measured in the excitation winding connection method, and repeating the measurement process until the highest detection band.

The invention relates to a halogen-free thermosetting resin composition and a prepreg and a printed circuit laminate employing the halogen-free thermosetting resin composition. An organic condensate of the halogen-free thermosetting resin composition comprises the ingredients in parts by weight (based on 100 parts): (A) 5-50 parts of cyanate resin; (B) 5-40 parts of polyphenylether resin; (C) 5-30 parts of phosphoric bisphenol polymer; (D) 30-60 parts of halogen-free epoxy resin. The prepreg and the printed circuit laminate made from the halogen-free thermosetting resin composition, provided by the invention, have high glass transition temperature, excellent dielectric properties, low water absorption rate, high heat resistance, high peel strength, excellent humidity resistance and good process processability, can achieve no halogen and flame retardance and reaches UL94 V-0.

The invention provides a halogen-free thermosetting resin composition, a prepreg comprising the same, a laminated board and a printed circuit board. The halogen-free thermosetting resin composition comprises the following substances serving as necessary components, in 100 parts of organic solid matters by weight: (A) 35-65 parts of halogen-free epoxy resin; (B) 10-35 parts of poly-phosphonate; (C) 10-30 parts of cyanate ester. The halogen-free thermosetting resin composition, the prepreg comprising the same, the laminated board and the printed circuit board have high glass transition temperature, excellent dielectric property, high peeling strength, high heat resistance, low water absorption and good process machinability, can realize halogen-free flame resistance and reach UL94 V-0.

The invention provides a micro inertial switch with a Z-shaped beam structure. The micro inertial switch has a micro inertial switch chip which is processed according to MEMS technology and has a low g-value. The micro inertial switch is mainly composed of a glass cover plate, a mass block and spring beam silicon structure, a glass substrate, etc. The spring beam structure is a symmetrical Z-shaped beam. In operation, on the condition an overload function exists in a sensitive direction, the Z-shaped beam deforms elastically, and the mass block moves to contact bump points in the groove of the glass substrate. On the condition that overload reaches a certain threshold, a metal electrode on the mass block contacts with two random adjacent contact pump points in the groove of the substrate, so that the micro inertial switch is on. The micro inertial switch with the Z-shaped beam structure has advantages of high transverse overload resistance, high productivity, high reliability, etc. The micro inertial switch with the Z-shaped beam structure is suitable for the fields such as automobile and industrial production safety control and aeronautics and astronautics.

The invention uses ethylenediamine as cationic donor, uses nitrophenols which have different numbers of nitro groups and are substituted in different sites, as anionic donor, uses one or more of water, ethanol, methanol, propanol, isopropanol and acetone as reaction medium and utilizes the acid-base reaction to synthesize a series of ethylenediamine-dinitrophenol type ionic liquids. The synthesized ionic liquids have higher structural symmetry, higher thermal stability and good compatibility to metals, high polymer materials and other inorganic materials, contain more coordination centers and belong to a new type of materials with broad application prospect.

The invention discloses a high-heat-stability locking joint. The high-heat-stability locking joint comprises a first connecting piece 1, a second connecting piece 2, fixed-pressure locking devices 3,a rotating shaft module 4 and low-impact release devices 5; the first connecting piece 1 and the second connecting piece 2 are fixedly connected with rod pieces, and form a rotating pair through a rotating shaft 42 and a bearing 43; the hinging between the first connecting piece 1 and the second connecting piece 2 is realized; and the fixed-pressure locking devices 3 with constant pressing force are arranged at two ends of the rotating shaft 42, and can realize locking through the low-impact release devices 5. Through reasonable layout of the fixed-pressure locking devices 3, the rotating shaft module 4 and the low-impact release devices 5, the whole joint is symmetrical relative to two planes passing through the axles of the rod pieces, so that the problem of weak symmetry of a traditional locking joint is overcome; through deformation of flexible supports 36, the axial gapless locking is realized, the locking gap of the traditional locking joint is eliminated, and the locking rigidity is improved; and through arrangement of the fixed-pressure locking devices 3 and the low-impact release devices 5, the same pretightening force at two ends of the rotating shaft 42 is guaranteed, and the problem of weak heat stability of the traditional locking joint is solved.

The invention relates to a special amino modified perfluorosulfonic membrane for a fuel cell, and a preparation method, belongs to the technical field of a fuel cell diaphragm and aims to solve the technical problems. The preparation method comprises the steps of performing sulfonation of tetrafluoroethylene, fluorination of 3-amino propylene, a condensation reaction, a condensation polymerizationand acidizing and the like; by virtue of combination of N atoms and dual-short sulfonic acid group branch chains, grafted polymerization on the main chain is realized, so that the sulfonic acid groupcontent and structural symmetry are improved; therefore, the membrane material structure in the swelling process is more stable, and ion clusters can be formed in the membrane material more easily, thereby improving proton adsorption and mobility capabilities; the method is simple in process and high in feasibility; and the prepared amino modified perfluorosulfonic membrane is high in structuralsymmetry, high in regularity, easy to crystallize, relatively high in membrane material mechanical strength, high in proton conductivity and suitable for a high-temperature and low-moisture environment.

The invention discloses a production process of a hydrophobic polyimide film, which belongs to the technical field of modified polyimide film preparation. The production process of the hydrophobic polyimide film comprises the following steps of preparing a diamine monomer A, reacting a diamine monomer A with a dianhydride monomer to prepare a polyamic acid solution, and performing imidization to obtain a polyimide film. A diamine monomer A is prepared, so that the prepared polyimide has a C-F bond and a siloxane chain with excellent hydrophobic performance, the diamine monomer A is provided with an ester group in the middle, the structural symmetry degree of the diamine monomer A is relatively high, a polymer can locally form microcrystals, and due to the existence of the local microcrystals, the diffusion of water molecules in the polymer is hindered; when water molecules encounter local microcrystals of a macromolecular chain, macromolecular chain segments in a crystalline structure are tightly piled, so that the water molecules cannot permeate and diffuse, the advancing of the water molecules is blocked finally, and the hydrophobic performance of the film is further improved.

The invention relates to the field of grinding media, and aims at solving the problems that raw material powder used by an existing ceramic grinding body is poor in dispersity and easy to agglomerate, so that the internal density of the ceramic grinding body obtained through final sintering is not uniform enough, the hardness of the ceramic grinding body is poor, abrasion is large, and the grinding cost is high. According to the composite grinding medium for the grinding machine and the preparation method of the composite grinding medium, the grinding medium prepared by taking modified silicon carbide as a main raw material is good in mechanical property and high in wear resistance, so that the service life of the grinding medium is prolonged, and the grinding cost can be reduced while the grinding effect can be guaranteed; the modified silicon carbide has better performance and has a forward promotion effect on the performance of the grinding medium, and the dispersity of the silicon carbide can be modified by using the ball milling accelerant, so that the phenomenon that the internal connection of the grinding medium is not tight enough due to agglomeration of the modified silicon carbide is avoided, and the service life of the grinding medium is prolonged. And the mechanical property and wear resistance of the grinding medium are further improved.

The invention discloses a mass balance processing device for a hemispherical resonator and a working method. The mass balance processing device comprises a shaft sleeve and a vessel; one end of the shaft sleeve is connected with a shaft handle end of a hemispherical resonator to be subjected to balance processing, and the other end of the shaft sleeve is connected with a rotation shaft; the otherend, connected with the shaft sleeve, of the rotation shaft is connected with a rotating shaft of a rotation motor; the shaft handle end of the hemispherical resonator to be subjected to balance processing, the shaft sleeve, the axis of the rotation shaft and the axis of the rotating shaft of the rotation motor are located on the same extension line; a lifting structure capable of driving the whole mass balance processing device to ascend or descend is arranged on the rotation shaft; and chemical corrosive liquid capable of corroding the hemispherical resonator to be subjected to balance treatment is placed in the vessel. According to the technical schemes of the invention, the geometric deviation of the hemispherical resonator can be corrected, so that the nonuniformity of mass distribution of the hemispherical resonator is reduced.