468results about How to "Good performance and stability" patented technology

According to one embodiment, a neurological stimulation system is adapted for implantation into a person's body for electrical, chemical, or combined electrical and chemical stimulation of target nerve tissue in the person's brain stem. For electrical stimulation, the system includes an electrical stimulation lead adapted for implantation on, in, or near the brain stem, and including electrodes adapted to be positioned on, in, or near target nerve tissue in the brain stem, for delivering electrical stimulation energy to the target nerve tissue. For chemical stimulation, the system includes an infusion catheter adapted for implantation on, in, or near the brain stem, and including openings adapted to be positioned on, in, or near target nerve tissue in the brain stem, for delivering a chemical to the target nerve tissue. The system also includes a stimulation source adapted for implantation in the person's body and operable to generate pulses of electrical stimulation energy or pulses of the chemical, for delivery to the target nerve tissue in the brain stem.

The invention belongs to the technical field of battery materials, and discloses a preparation method of an aluminum oxide coated lithium nickel manganese cobalt cathode material. The method comprises the steps of raw material mixing, primary sintering, doping, secondary sintering, coating and size stabilization treatment, wherein the step of raw material mixing comprises the steps that a three-dimensional efficient titled mixer is adopted, polyurethane balls serve as a mixing medium, dispersing, even mixing and smashing are conducted on lithium carbonate, a nanometer spherical nickel cobalt manganese hydroxide precursor and polyethylene glycol, and a uniform intermediate mixture is formed. The preparation method of the aluminum oxide coated lithium nickel manganese cobalt cathode material is low in primary sintering temperature, short in sintering time, simple in technology, large in specific capacity and good in cycling performance. The preparation method further has the advantages of being low in investment, reliable in technology, low in operating cost and the like, and the good economic benefit and market promotion value are achieved.

The application provides a method and device for automatically deploying a cluster. The method comprises steps of: obtaining the role information of each cluster member in a cluster to be deployed; obtaining, based on the role information of each cluster member, cluster configuration information corresponding to the cluster members; generating a configuration file required to execute a script based on the cluster configuration information of each cluster member; executing the configuration file and configuring the cluster members by using the cluster configuration information of each cluster member so as to complete the cluster deployment. The method and device can facilitate cluster deployment, install the service of the required roles on different machine nodes according to different roles, can conveniently and quickly achieve cluster installation, deployment, use and management, and is good in performance and stability.

A catalyst and process is disclosed to selectively upgrade a paraffinic feedstock to obtain an isoparaffin-rich product for blending into gasoline. The catalyst comprises a support of a tungstated oxide or hydroxide of a Group IVB (IUPAC 4) metal, a phosphorus component, and at least one platinum-group metal component which is preferably platinum. The catalyst has a structure other than a hetropoly anion structure.

The invention discloses a hot rolling wire rod for a 60 kg-stage high-strength welding wire and a production method thereof. The hot rolling wire rod comprises the following chemical components including, by mass, 0.06% to 0.12% of C, 0.40% to 0.80% of Si, 1.50% to 2.00% of Mn, 0.020% or less of P, 0.020% or less of S, 0.040% to 0.060% of V, 0.050% to 0.090% of Ti, 0.20% to 0.45% of Cr and the balance Fe and unavoidable impurities. The production method comprises steel making, continuous casting, heating, rolling, spinning and cooling procedures. According to the hot rolling wire rod for the 60 kg-stage high-strength welding wire and the production method thereof, the hot rolling wire rod for high-strength welding is produced through vanadium and titanium alloying, microstructures of equiaxial ferrite and pearlite are obtainedin cooperation with control over the finish rolling temperature, spinning temperature, cooling temperature and winding temperature, the hot rolling wire rod is processed into a gas shielded welding rod, the deposited metal tensile strength is 600 MPa to 700 MPa, and the wire rod is low in cost and good in performance stability.

The invention relates to a low-loss high-voltage ceramic capacitor dielectric which is characterized by comprising the following raw materials in percentage by weight: 58-91% of BaTiO3, 1-3% of SrTiO3, 4-20% of BaZrO3, 3-12% of CaZrO3, 0.03-1.0% of CeO2, 0.1-1.5% of ZnO and 0.5-4.5% of Bi2TiO5. The low-loss high-voltage ceramic capacitor dielectric provided by the invention has the advantages of high voltage resistance, low dielectric loss and no environment pollution in the preparation and use process, can lower the cost of the ceramic capacitor, and is suitable for preparing single-chip ceramic capacitors and multilayer chip ceramic capacitors.

The invention relates to a thermoplastic composite solid propellant and a preparation method thereof, and belongs to the technical field of composite solid propellant preparation. The invention relates to the thermoplastic composite solid propellant and the preparation method thereof. The melting temperature of the thermoplastic composite solid propellant is lower than 95 DEG C on the premise thata solvent and a liquid plasticizer are not added, the viscosity of molten slurry is low, the safety performance is excellent, and additive manufacturing of the composite solid propellant can be achieved through a fused deposition technology; the energy level of the thermoplastic composite solid propellant is equivalent to that of a medium-energy thermosetting propellant, and the thermoplastic composite solid propellant can be used as a power source of a complex-drug-type solid engine and a layered variable-thrust solid engine in the future.

The invention realtes to a high-stability recyclable surface-enhanced Raman substrate and a preparation method and belongs to the technical field of trace-amount organic substance detection. In the method, a silver nanorod array thin film is prepared through an inclined growing method and then an amorphous-state titanium oxide thin film is uniformly deposited onto a surface of the silver nanorod array thin film through an atomic layer deposition method to obtain a silver-at-titanium oxide composite nanorod array thin film as the surface-enhanced Raman substrate. By means of the substrate, a surface-enhanced Raman signal is free from being attenuated greatly due to the ultrathin titanium oxide layer. The substrate is excellent in enhancement effect. Meanwhile, the titanium oxide thin film enables silver nanorods to be isolated from external environment so that the silver nanorods are enhanced in anti-oxidizing and anti-vulcanizing performance, thereby greatly enhancing stability of the substrate. The titanium oxide, as a photocatalytic material, can catalytically decomposing organic substances adsorbed on the surface of the substrate with combination of an ultraviolet light. The substrate, after being irradiated by the ultraviolet light, can be recycled as a clean substrate. The substrate has a wide application prospect in the field of the trace-amount organic substance detection.

The invention belongs to the field of oxygen preparation through photocatalysts by decomposing water with visible lights and discloses a nickel titanium hydrotalcite and graphene composite photocatalyst responsive to visible lights and a method for preparing the same. Grapheme serves as an electric transmission body template, the nickel titanium hydrotalcite and graphene composite photocatalyst of uniform partical sizes and good dispersibility is deposited on the surface, and large surface areas and more active centers are provided. A series of photocatalysts with superior performances and efficient water decomposition oxygen preparation effects under visible lights can be obtained by regulating composition ratios of metals of different valence states on hydrotalcite laminate and load amounts of carrier grapheme, and photocatalytic performances of the photocatalyst are superior to those of traditional WO3 photocatalysts.

The invention discloses a method for preparing phthalide through phthalic anhydride liquid phase hydrogenation under the action of au-base catalyst. The gold-base catalyst used in the preparation method takes SiO2, ZnO, La2O3, CeO2, TiO2, ZrO2 or Fe2O3 as a carrier and takes gold as an active component, and the loading of gold is between 0.05 and 20 percent. As the gold-base catalyst used in the preparation method has excellent hydrogenation activity and selectivity under mild catalytic reaction conditions, the conversion rate of phthalic anhydride can be more than 95 percent, and the selectivity of phthalide can be more than 93 percent, thereby the single pass yield of the target product phthalide is high. Moreover, the gold-base catalyst is very good in performance stability, and more particularly, the gold-base catalyst after metal oxide modification can still maintain the selectivity over 92 percent even through the activity of the gold-base catalyst declines slightly after repeated recycling use. In addition, the gold-base catalyst provided is simple to prepare and does not pollute the environment. Therefore, the preparation method has significant advantages.

The invention discloses a thermal insulation silicon dioxide aerogel / hydroxylation glass fiber felt composite and a preparation method thereof. The thermal insulation silicon dioxide aerogel / hydroxylation glass fiber felt composite is characterized in that silicon dioxide aerogel accounts for 50-80 weight parts of a matrix, and hydroxylation glass fiber felt accounts for 70-120 weight parts of a reinforcing body. The thermal insulation silicon dioxide aerogel / hydroxylation glass fiber felt composite is prepared by preparing a silica sol system of an MQ structure (M represents (CH3)3SiO1 / 2, Q represents SiO4 / 2) through raw materials including absolute ethyl alcohol, deionized water, hexamethyldisiloxane and the like under the acid catalysis environment, then adding gel catalysts, submerging preprocessed glass fiber in the silica sol system to form a wet gel and fiber felt composite, conducting soaking through normal hexane after ageing is conducted for 12-24 h so that water in the system can be removed, and conducting drying to obtain the silicon dioxide aerogel / hydroxylation glass fiber felt composite at temperature of 50-120 DEG C and pressure of 0.01-5 Pa for 1-5 h.

The invention provides a medium of a high-voltage ceramic capacitor with high performance and middle-low temperature sintering, which relates to the technical field of inorganic non-metal material. The invention adopts the prior method for preparing the medium of the high-voltage ceramic capacitor to prepare the medium of the high-voltage high-stability ceramic capacitor containing no lead, cadmium or other toxicities, and having high performance and middle-low temperature sintering (the sintering temperature is between 1,100 and 1,150 DEG C) by the prior chemical raw materials of capacitor ceramics. The medium is applicable to the preparation of single-chip ceramic capacitor and multi-layer tablet ceramic capacitor so as to greatly reduce the cost for the ceramic capacitor and avoid environmental pollution during preparation and application. The medium is characterized in that the medium comprises the following compositions (in weight percentage): 58 to 92 percent of BaTiO3, 2 to 19 percent of SrTiO3, 0.5 to 10 percent of CaZrO3, 0.05 to 1 percent of Nb2O5, 0.03 to 1.0 percent of Y2O3, 0.03 to 1.0 percent of Co2O3, and 6 to 30 percent of Bi2Sn2O7, wherein each of the BaTiO3, the SrTiO3 and the CaZrO3 is synthesized by a solid phase method by the prior chemical materials. The medium has high voltage resistance reaching over 10kilovolt / millimeter, specific inductive capacity of between 2,200 and 3,500 and small variance ratio of capacitance temperature, accords with the requirement on X7R property, Y5T and Y5U property, has excellent stability and high security when used, and does not pollute environment.

The present invention discloses a weathering resistance modified asphalt waterproof coiled material, wherein a glass fiber felt or polyester felt is adopted as a reinforcement, a weathering resistance modified asphalt layer is coated on the upper surface of the reinforcement, a modified asphalt layer with the characteristic of easy hot melting is coated on the lower surface of the reinforcement, a mineral particle layer is covered on the upper surface of the weathering resistance modified asphalt layer, and a polyethylene film is covered on the lower surface of the modified asphalt layer with the characteristic of easy hot melting. According to the present invention, the weathering resistance modified asphalt waterproof coiled material has characteristics of long service life, high waterproof performance, low construction temperature, reduction of aging of the modified asphalt at the high temperature, and reduction of environment pollution, and can be used for industrial and civil building roofing waterproof projects at different temperatures in different regions.

The invention discloses conductive ink which comprises, in weight percentage, 5-50% of silver nano-wire dispersion liquid, 0.1-5% of conductive macromolecules, 0.01-0.5% of silane coupling agents, 0.1-5% of viscosity adjusting agents, 5-40% of organic solvents, 5-40% of deionized water, 0.1-5% of macromolecule resins, 0.1-5% of pH (potential of hydrogen) value adjusting agents, 0.1-0.5% of non-ionic surface active agents, 0.01-0.5% of wetting dispersants, 0.01-0.5% of leveling agents, 0.01-0.5% of defoaming agents and 0.01-1% of metal nano-particles. The invention further discloses a preparation method of the conductive ink, a reel-to-reel conductive film and a preparation method of the reel-to-reel conductive film. The conductive film prepared by the conductive ink has the advantages of low resistance, haze and production cost, good conductivity and high light transmittance and can be optionally bent and twisted, and the requirements of flexible touch screens can be met.

The invention relates to the technical field of inorganic nonmetallic materials, in particular to a barium calcium zirconate titanate leadless piezoelectric ceramic material. A formula comprises components as follows: 91wt.%-98 wt.% of (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3, 0.1 wt.%-7.0wt.% of BiFeO3, 0.01 wt.%-1wt.% of Bi2WO6, 0.1wt.%-4wt% of Ba(Yb1 / 2Nb1 / 2)O3 and 0.01wt.%-1.8wt.% of Co2O3, wherein (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 is prepared from ordinary chemical raw materials for piezoelectric ceramics, the leadless piezoelectric ceramics which are cadmium-free and have a high-tension electricity property are prepared, the sintering temperature of the piezoelectric ceramics can be greatly reduced, the barium calcium zirconate titanate leadless piezoelectric ceramic material is suitable for preparing a piezoelectric ceramic sensor, and the cost of the piezoelectric ceramics can be greatly reduced.

The invention provides a dielectric medium of a ceramic capacitor, which is prepared from the following raw materials in percentage by weight: 54 to 91 percent of BaTiO3, 2 to 13 percent of SrTiO3, 2 to 15 percent of BaZrO3, 0.05 to 1 percent of Nb2O5, 0.03 to 1.0 percent of CeO2, 0.1 to 1.0 percent of ZnO, 0.03 to 1.0 percent of Co2O3, and 2 to 15 percent of BaSiO3. The invention also provides apreparation method of the dielectric medium of the ceramic capacitor. The dielectric medium of the ceramic capacitor has high dielectric constant and high withstand voltage, generates no pollution tothe environment in the process of preparation and use, and can reduce the cost of the ceramic capacitor, so the dielectric medium is suitable for preparing monolithic ceramic capacitors and multilayer chip ceramic capacitors.

The invention provides pump concrete doped with low-quality recycled micropowder and low-quality recycled aggregate, and belongs to the field of building materials. The pump concrete is composed of the following raw materials including cement, the low-quality recycled micropowder, slag powder, fly ash, mixed fine aggregate, mixed coarse aggregate, a compound pumping agent and water, wherein the mixed fine aggregate is composed of low-quality recycled fine aggregate and common fine aggregate; the mixed coarse aggregate is composed of low-quality recycled coarse aggregate and common coarse aggregate; and the compound pumping agent comprises a salt of sulfonated polystyrene-acrylic acid copolymer and a salt. The pump concrete has the characteristics of good work performance and excellent mechanical properties and durability, and can be pumped easily.

The invention discloses a high-stability surface-enhanced Raman substrate and a preparation method thereof and belongs to the technical field of detection on trace organic substances. The preparation method of the high-stability surface-enhanced Raman substrate comprises the following steps: preparing a silver nanorod array by an oblique growth method and then uniformly coating the surface of silver nanorods with an amorphous-state aluminum oxide film by a low-temperature atom layer deposition technology. Due to the adoption of relatively low deposition temperature in the substrate prepared by the method, the shape of the silver nanorods is unchanged; meanwhile, by virtue of the ultrathin aluminum oxide film, a surface-enhanced Raman effect is not greatly attenuated, so that the substrate has a good surface-enhanced Raman effect; the surface of the silver nanorods is uniformly coated with the aluminum oxide film, so that the silver nanorods are isolated from an outside environment, the oxidation resistance and the vulcanization resistance of the silver s are improved, and the stability of the surface-enhanced Raman effect of the silver nanorods is greatly improved; the high-stability surface-enhanced Raman substrate has wide application prospects in the aspects of trace and fast detection on organic substances.

The invention discloses a self temperature limiting heat tracing strip of a PTC (positive temperature coefficient) high polymer conductive composite material, which comprises a flat strip that comprises a polyethylene PTC conductive complex layer. Two conductive core wires are extrusion coated inside the polyethylene PTC conductive complex layer. A polyethylene insulating layer, a shielding layer and a polyethylene reinforced protective layer closed in periphery are arranged orderly outside the polyethylene PTC conductive complex layer from inside to outside. The invention further discloses a preparation method of the self temperature limiting heat tracing strip, which comprises the steps of preparing the polyethylene PTC conductive complex layer; extrusion coating the two conductive core wires; and arranging the polyethylene insulating layer, the shielding layer and the polyethylene reinforced protective layer closed in periphery orderly outside the polyethylene PTC conductive layer from inside to outside. The self temperature limiting heat tracing strip provided by the invention will not generate bubbles, and is stable in electrothermal performance, safe and reliable. The preparation method provided by the invention has simple process flows and low cost, and is easy to realize.

The invention provides a Ni-Fe-Mn-Al alloy material, which has a chemical formula of Ni<50-x>Fe<x>Mn<50-y>Al<y> (2=<x=<9, 16<=y<=18). The preparation comprises the following steps: (1) weighting pure elements according to the ratio of the chemical formula, mixing the pure elements together; (2) placing the mixed material in a water-cooling copper crucible, and repeatedly smelting the mixed material through a conventional electric arch smelting method so as to obtain a uniform alloy casting ingot. The obtained polycrystalline casting ingot can be made into Ni<50-x>Fe<x>Mn<50-y>Al<y> rapidly-quenched strips with a certain texture through a melt quick quenching method. Compared to that of the conventional Ni-Mn base ferromagnetic shape-memory alloy, the binding strength among the crystals of the Ni-Fe-Mn-Al alloy is higher, and thus the mechanical property of the Ni-Fe-Mn-Al alloy is better. The Ni-Fe-Mn-Al alloy is prepared through a conventional method, the raw materials are cheap, and furthermore, the Ni-Fe-Mn-Al alloy has a strong magneto-thermal effect under a low magnetic field, so the Ni-Fe-Mn-Al alloy can be applied to the magnetic refrigeration field.

The invention provides a protective fabric, a preparation method and application thereof. The protective fabric comprises an antistatic base cloth layer, a waterproof and moisture permeable layer, anantibacterial layer and an antiviral coating which are arranged in sequence. The material of the antiviral coating comprises a compound of graphene and nano titanium dioxide. The antistatic base clothlayer is obtained through a weaving method, then the antistatic base cloth layer is compounded with the waterproof and moisture permeable layer, then the antibacterial layer is obtained through a padding process, and finally the antiviral coating is sprayed. The protective fabric achieves performance balance in the aspects of antibacterial properties, antiviral properties, antistatic properties,waterproof and moisture-permeable properties and comfort level; the antiviral coating has photocatalytic oxidation bacteriostatic and antiviral activity, and cooperates with the antibacterial layer, so that the protective fabric has lasting, stable and broad-spectrum antibacterial and antiviral performance, the protective performance cannot be attenuated along with repeated washing, the protectivefabric has good performance stability and can be used repeatedly, the cost of protective clothing is effectively reduced, and the protective fabric is more energy-saving and environment-friendly.

The invention provides a method for preparing a medical tracheal catheter capable of resisting bacterial adhesion and performing photo-induced sterilization. The method includes the preparation of TiO2 and a composite oxide coating liquid, and the film forming of a coating liquid on the inner surface of a PVC tracheal catheter. Specifically, the preparation method comprises the following steps: a suspension coating liquid is formed by mixing and dissolving an organic polymer binder in a crystalline state semiconductor oxide sol or a suspension characterized by photo-catalytic activity; and then a thin film with the advantages of high bonding strength, good anti-bacterial performance and excellent lighting sterilization performance is formed by plating the coating liquid uniformly on the surface of the inner wall of a tracheal catheter with a modified surface. The preparation technology can enable the medical PVC tracheal catheter to resist bacterial adhesion and to retain the effectiveness and stability of the photo-induced sterilization performance for a long period.

The invention discloses a processing method for smelting TC4 alloy ingots by an electron beam cold-bed furnace. The method includes steps: adopting the electron beam cold-bed furnace for primary smelting to obtain the TC4 alloy ingots; subjecting the TC4 alloy ingots to direct rolling treatment to obtain TC4 alloy plates. A final-state structure of the TC4 alloy plates is an equiaxed structure, and small grain size and excellent mechanical property stability are realized. The method is free of a forging step, has the advantage of short processing route and is especially suitable for preparation of large-size wide plates. Stability and reliability in application of the electron beam cold-bed furnace to TC4 alloy smelting are guaranteed.

The invention discloses a method for preparing modified lithium nickel manganese oxide which is the anode material of a lithium ion battery. The method comprises the following steps: mixing a manganese salt material and a nickel salt material, and preparing a nickel manganese precursor through a sol-gel method; mixing the nickel manganese precursor and the nickel salt by using a three-dimensional oblique type mixing machine; presintering and high temperature sintering, and doping F- or F- and metal cations, then adding a metallic oxide and performing wet coating; and finally, acquiring a lithium nickel manganese oxide finished product by low temperature sintering, fluid energy milling and grading. The method provided by the invention uses an ion doping modification technology to improve the cycle performance and high temperature stability of the lithium nickel manganese oxide, and uses a wet coating technology to improve the high pressure cycle performance and high temperature stability of the lithium nickel manganese oxide.

The invention relates to the technical field of magnetic materials, and discloses a preparation method of a nanocrystalline magnetic sheet for wireless charging. The method comprises the steps of 1, coiling; 2, annealing; 3, single-layer laminating; 4, multi-layer laminating; 5, roll cutting; 6, splintering; 7, cutting, wherein silica gel weak mucosa on a nanocrystalline strip is stripped and cutinto nanocrystalline articles; 8, coating, wherein colloid mixed with nanoscale solid insulation powder is coated on the nanocrystalline articles and subjected to vacuum plastic packaging through a vacuum bag; 9, isostatic pressing, wherein plastic-packaged nanocrystalline articles are laminated through warm water isostatic pressing, and the nanoscale solid insulation powder enters cracks of the nanocrystalline articles; 10, laminating; 11, die cutting. Accordingly, the technology of conducting laminating first and then conducting splintering is adopted, the production efficiency can be effectively improved, in the splintering process, the problems of corrugation, centipede grains, off tracking and the like cannot occur easily, and the splintering performance stability is good. In addition, laminating is conducted before splintering, a magnetic sheet is not likely to be shredded, and the yield is higher.

The invention provides a high strength steel for a thick wall water pipe. The steel comprises the following components: 0.040%-0.070% of C, 0.10%-0.40% of Si, 1.50%-1.65% of Mn, 0.050%-0.080% of Nb, 0.030%-0.050% of V, 0.20%-0.30% of Cr, 0.005%-0.025% of Ti, 0.015%-0.050% of Als, less than or equal to 0.020% of P, less than or equal to 0.008% of S, less than or equal to 0.008% of N, less than or equal to 0.002% of O, and the balance Fe and inevitable impurities. The manufacturing method of the steel includes: conducting continuous casting to make a continuous casting plate blank, subjecting the continuous casting plate blank directly to hot charging furnace heating at 500-850DEG C, heating the continuous casting plate blank by a reheating furnace to 1150-1230DEG C, discharging it, then carrying out two-stage controlled rolling by roughing rolling and finish rolling units, controlling the initial rolling temperature of rough rolling at 1180-1100DEG C and the final rolling temperature of rough rolling at 1010-960DEG C, keeping the initial rolling temperature of finish rolling at 980-920DEG C and the final rolling temperature of finish rolling at 780-850DEG C, and maintaining the compression ratio of finishing rolling greater than 60%; then subjecting a steel strip to rapid cooling by means of laminar cooling at a speed of 10-20DEG C / s; and performing reeling at 500-580DEG C.

The invention discloses an asphalt tile. The asphalt tile is of a multilayer structure, and consists of a mineral particle layer, a glass fiber felt, modified asphalt coating layers and an isolation material layer from top to bottom, wherein the mineral particle layer and the glass fiber felt are arranged on the upper surface, the modified asphalt coating layers are arranged at the two surfaces of the glass fiber felt, and the isolation material layer is arranged on the lower surface. The asphalt tile has the advantages that the good mineral particle adhering performance, anti-aging performance and flame-retardant performances are realized; the asphalt tile can be applied to various types of building roofs, especially the slope roofs of civil houses and villas.

The invention relates to the technical field of inorganic nonmetallic materials, in particular to low-temperature-sintered giant-dielectric ceramic capacitor dielectric with the low capacitor temperature change rate.The low-temperature-sintered giant-dielectric ceramic capacitor dielectric is prepared from 88 wt%-96 wt% of CaCu3Ti4O12, 0.01 wt%-7.0 wt% of (Ba0.65Sr0.35)TiO3, 0.01 wt%-6 wt% of Bi2WO6, 0.01 wt%-0.6 wt% of Nd2O3, 0.1 wt%-4 wt% of SiO2-Li2O-B2O3 glass powder (ZLB), 0.01 wt%-0.5 wt% of BiMnO3 and 0.5 wt%-4 wt% of (Li(1 / 2)Bi(1 / 2))TiO3.The lead-free cadmium-free giant-dielectric ceramic capacitor dielectric with the low capacitor temperature change rate is prepared by adopting the ordinary chemical raw materials of capacitor ceramic, and the sintering temperature of the capacitor ceramic can be greatly lowered.

The invention relates to the field of semiconductor devices, and provides a HEMT device with a sandwich grid medium structure and a preparation method thereof. The HEMT device includes a substrate, a buffer layer arranged on the substrate, a GaN layer arranged on the buffer layer, a barrier layer, a source electrode, and a drain electrode that are arranged on the GaN layer, a passivation layer arranged on the source electrode, the drain electrode, and the barrier layer except a groove, a first dielectric layer coating the groove surface and the passivation layer surface, a second dielectric layer arranged on the first dielectric layer, a third dielectric layer arranged on the second dielectric layer and the first dielectric layer except the second dielectric layer, a gate electrode in contact with the third dielectric layer, a source electrode pad in contact with the source electrode, and a drain electrode pad in contact with the drain electrode, wherein one side, far away from the GaN layer, of the barrier layer is provided with the groove, and the second dielectric layer contains fluorinion. The high-threshold voltage normally off operation of the HEMT device can be realized, and the breakdown voltage of the device can be effectively improved.