166 results about "Hexagonal crystal system" patented technology

A fuel injection valve has a valve guide, a valve member movable in a center opening of the valve guide along an axial direction of the valve guide, and a covering layer disposed on a surface of the valve guide. The valve guide has a valve seat placed on an inner surface thereof and a nozzle hole from which fuel is injected. The valve member is seated on the valve seat to close the nozzle hole and leaves the valve seat to open the nozzle hole. The covering layer is placed around an outlet opening of the nozzle hole. The covering layer is made of boron nitride in a hexagonal crystal system so as to have a hydrophilic property higher than that of the surface of the valve guide.

A method of manufacturing a nitride semiconductor substrate according to example embodiments may include forming a buffer layer on a (100) plane of a silicon (Si) substrate. The buffer layer may have a hexagonal crystal system and a (1010) plane. A nitride semiconductor layer may be epitaxially grown on the buffer layer. The nitride semiconductor layer may have a (1010) plane. Accordingly, because example embodiments enable the use of a relatively inexpensive Si substrate, a more economical nitride semiconductor substrate having a relatively large diameter may be achieved.

The invention provides a vanadium selenide/carbon-based composite material, a preparation method of the material, and a negative electrode of a lithium ion battery. Vanadium selenide in the vanadium selenide/carbon-based composite material is of a hexagonal crystal system and is deposited on the surface of a carbon-based material, or the surfaces of vanadium selenide particles are at least partially coated with the carbon-based material to form vanadium selenide/carbon particles of a core shell-like structure; the vanadium selenide/carbon particles are connected through carbon nets to obtain the high conductivity. In the negative electrode of the power lithium ion battery, prepared from the vanadium selenide/carbon-based composite material provided by the invention, since selenide with the relatively large specific capacity is combined with the carbon-based material, the negative electrode has the characteristics of large capacity, high rate and high cyclic stability. Therefore, the negative electrode made of the composite material has the relatively large capacity, relatively long service life and relatively low price when applied to the lithium ion battery.

The invention provides a highly active potassium base solid absorbent for CO2 in the process of removing flue gas and a preparation method thereof. The solid absorbent takes hexagonal crystal system potassium carbonate as the active component, coal activated carbon or wood activated carbon or silochrom as a carrier; and the solid absorbent is made by a method of impregnation. The materials required by the absorbent is chemical medicine and carrier which are cheap and easy to be obtained; the preparation of the absorbent has simple process and low cost, the carbonatation temperature ranges from 60 DEG C to 80 DEG C, while the regeneration temperature ranges from 100 DEG C to 200 DEG C, and the absorbent belongs to a low-temperature absorbent. Under the temperature, the absorbent is not easy to lose activity, and can maintain a higher transformation ratio after multiple circulations. The highly active potassium base solid absorbent for CO2 in the process of removing flue gas and the preparation method provide a key technology for the application of the technique about removing the CO2 by a dry method for an alkali metal base absorbent and has a wide application prospect.

The invention relates to a flower-shaped MoS<2>@graphene nanocomposite and a preparation method therefor. The nanocomposite is prepared by adopting a one-step hydrothermal synthesis method; graphene oxide, sodium molybdate and sulfourea are taken as the raw materials, and purified water is taken as the solvent; and then the flower-shaped and uniformly-loaded MoS<2>@graphene nanocomposite is obtained under the auxiliary effect of glucose or glucosamine hydrochloride. A TEM/SEM result proves that the ultra-thin MoS<2> nanosheets form the special flower shape, and are loaded to the high-quality graphene in a mono-dispersion manner; and an XRD spectrogram can prove that the MoS<2> is good in crystallization, and belongs to a hexagonal crystal system 2H-MoS<2> crystal phase. The graphene nanocomposite is simple in process, controllable in conditions, and high in load uniformity of the materials; and the prepared MoS<2>@graphene nanocomposite has a wide application prospect in the fields of new energies, such as the negative electrode material of lithium ion batteries, and the like.

The invention relates to a numerical modeling method for a magnesium alloy dendritic structure, which aims at solving the problems that the dendritic growth of magnesium alloy cannot be accurately predicted at present and a kinetic model of close-packed hexagonal crystal system dendritic crystal growth is unclear. The method comprises the following steps: firstly, splitting a magnesium alloy dendritic mesh; secondly, distributing odd lines and even lines in a dislocating manner; thirdly, determining the computational domain of a model; fourthly, determining the number of hexagonal mesh crystalline form cores, the positions of the cores, the degree of super-cooling delta T and the solid fraction of meshes; fifthly, obtaining the growth rate Vtip of magnesium alloy dendritic arms; and sixthly, establishing a function shown in the specification. The method is applied to the field of numerical modeling of magnesium alloy dendritic structures.

The invention discloses a high magnetic-energy-product M type calcium series permanent magnetic ferrite material and a preparation method thereof. The high magnetic-energy-product M type calcium series permanent magnetic ferrite material is a hexagonal crystal system, and the chemical structural formula is R1-x-yCaxLayO.nFe(12-z)/nCoz/nO3, wherein x is greater than or equal to 0.001 and smaller than or equal to 0.4, y is greater than or equal to 0.001 and smaller than or equal to 0.5, z is greater than or equal to 0.01 and smaller than or equal to 2.0, 1-x-y is greater than 0.2 and smaller than or equal to 0.998, n is greater than or equal to 5.0 and smaller than or equal to 6.5. R is Sr or adopts Sr as the main component, and also contains one, two or three of Ba, lanthanide series Ce, Pr, La, Nd and Sm. When R is Sr and Ba, the content of Sr and Ba is less than or equal to 0.998. In addition to high residual magnetism and intrinsic coercivity, the high magnetic-energy-product M type calcium series permanent magnetic ferrite material provided by the invention also has higher magnetic induction coercivity and maximum magnetic energy product, and is particularly in favor of miniaturization of permanent magnetic ferrite devices.

The invention relates to a two-dimensional sheet MoS<2>@ graphene composite nano-material and a preparation method thereof. Pyrolysis reduced graphene oxide, polymine, sodium molybdate and thiourea are used as raw materials; water is used as a solvent; and thus, by means of a simple hydrothermal synthesis method, the sheet MoS<2>@ graphene composite nano-material having uniform morphologies and structures can be prepared under the auxiliary action of polymine. An electron microscope result shows that an ultra-thin MoS<2> nano-sheet is loaded on high-quality graphene vertically and uniformly and the dispersity is good. An XRD spectrogram shows that: compared with an unheated precursor, the crystallinity of a roasted MoS<2> material is obviously increased; and the roasted MoS<2> material belongs to a typical 2H-MoS<2> crystalline phase of a hexagonal crystal system. According to the two-dimensional sheet MoS<2>@ graphene composite nano-material and the preparation method thereof disclosed by the invention, a synthesis process is simple and controllable; the morphology homogeneous degree and the load rate of the material are high; the repeatability is good; and thus, the two-dimensional sheet MoS<2>@ graphene composite nano-material and the preparation method thereof disclosed by the invention have a certain application prospect in new energy fields, such as lithium ion batteries.

The invention discloses a calcium permanent magnetic ferrite material and a preparation method thereof. The calcium permanent magnetic ferrite material belongs to the hexagonal crystal system and has the following chemical structural formula: R1-x-yCaxLay.nFe2-zCoz/nO3, wherein 0.01<=x<=0.4, 0.1<=y<=0.75, 0.07<=z<=0.82, 5.0<=n<=6.5, 0<=1-x-y<=0.5; R is one or two or three of Ba, Sr and total 16 lanthanide series chemical elements not containing La; and when R is Ba and Sr, the content of Ba and Sr is smaller than 0.2. Compared with the traditional permanent magnetic ferrite, the permanent magnetic ferrite material provided by the invention only contains a small quantity of Ba and Sr; and under the temperature of 1150 DEG C or lower sintering temperature, the value of residual magnetism Br can reach 4200-4700Gs, and the value of intrinsic coercivity HJC reaches 4500-6200kOe. The calcium permanent magnetic ferrite of the invention has high residual magnetism and intrinsic coercivity, and can maintain high residual magnetic flux density after a sintered type magnet is diminished and thinned.

The invention discloses a silica dioxide porous material and process for preparation, wherein the material is provided with pure-projector helical band or hollow ball appearance. The invention uses the acid or salt of chiral anion surface activator as main structure guiding agent, under alkali or acid, uses the alkali silane with amido group as auxiliary structure guiding agent, and uses organic silane as silicon source, under different reaction temperatures to prepare two silica dioxide porous materials with different appearances, wherein the invention prepares silica dioxide porous material with pure-projection helical band appearance under 0-5DEG C, and forms silica dioxide porous material with hollow ball appearance under 8-15DEG C, which has two-dimension hexagonal crystal system p6mm structure. In addition, the wall of hole of the material is uniformly distributed with amido function group, to expand application range in the technical fields as drug separation, drug load, and catalysis or the like.

The present invention provides a nonaqueous electrolyte secondary cell having a positive electrode comprising mainly of a positive electrode active material, a negative electrode, and a nonaqueous electrolyte. The positive electrode active material is a lithium-containing transition metal composite oxide of a hexagonal crystal system that includes a compound represented by the general formula LiCo_1-xM_xO₂, where M is at least one species selected from the group consisting of V, Cr, Fe, Mn, Ni, Al, and Ti, and x is a decimal number in a range 0<x<1, magnesium, and halogen. In a nonaqueous electrolyte secondary cell having such a construction, the high-temperature characteristics are improved without reducing the cell capacity.

The invention relates to a preparation method of a novel WO3 nanosphere, and pertains to the technical field of nanometer material manufacturing processes. The preparation method is characterized in that: tungstic acid sol is controlled at a certain pH value condition, different ratios of a mineralizer and raw materials are selected, reaction conditions such as different reaction vessel filling degrees, reaction time and the like are maintained, and the novel WO3 nanosphere one-dimensional material is prepared by using a hydrothermal method. Crystalline phase, morphology, size and the like of the product are analysed by using characterization methods such as X- ray powder diffraction (XRD), scanning electron microscope (SEM) and the like. The analysis result shows that the novel WO3 nanosphere one-dimensional material formed by stacking hexagonal crystal system WO3 ingots can be prepared successfully by using the method provided in the invention, and the radius of the prepared WO3 nanosphere is 2-2.5mum.

The invention provides a preparation method of permanent magnetic ferrite low-temperature pre-sintering powder. The ferrite pre-sintering material is a permanent magnetic ferrite material of a hexagonal crystal system taking strontium as one of the major raw materials, and the molecular formula is SrO.mFe2O3, wherein m is greater than 5 and less than 6; and a low-melting sintering aid is a mixture of two or more of CaCO3, SiO2 and ZrO2, wherein the dosage of CaCO3 (z%) accounts for 1-10% of the total material weight, the dosage of SiO2 (y%) accounts for 0.1-10% of the total material weight, and the dosage of ZrO2 (wt%) accounts for 0-5% of the total material weight. The preparation method comprises the following steps of: (1) mixing Fe2O3 and strontium carbonate powder; (2) performing wet-process ball milling on the mixture to obtain slurry; (3) pressing the slurry into a cake and drying and directly pre-sintering; and (4) performing dry-type coarse grinding on the pre-sintered material. By adopting the processes such as optimization of a raw material formula, a superfine powder ball milling technology, addition of a low-melting sintering aid and the like, the preparation method provided by the invention produces high-performance strontium ferrite low-temperature pre-sintering powder, and the pre-sintering temperature is 100 DEG C lower than that of a conventional pre-sintering material; and meanwhile, the preparation method has the advantages of simple production technology and low energy consumption, and brings broad social and economic benefits.

The invention provides a nickel nitride nanometer composite electrocatalytic material, and a preparation method and application thereof. The structure of the nickel nitride nanometer composite electrocatalytic material belongs to a hexagonal crystal system, and the nickel nitride nanometer composite electrocatalytic material has a particle size of 100-200 nm. The preparation method comprises the following steps: preparation of a nickel nitride nanomaterial; sintering of nickel nitride nanomaterial; and deposition of platinum nanoparticles. The catalyst is prepared by compounding the nickel nitride nanomaterial and metal platinum particles (Ni3N/Pt); nickel nitride has high electrical conductivity and can form an electronic channel without hindrance by the Schottky barrier after compoundingwith Pt; and appropriate metal hydroxide catalytic active sites are cooperatively utilized so as to effectively improve electron transfer efficiency during electrolysis of water, so startup overpotential and the consumption of the precious metal Pt in electrolysis of water for hydrogen production can be reduced.

The invention provides a scintillation crystal magnesium tantalum oxide. The chemical formula of the crystal is Mg4Ta2O9, the crystal belongs to a hexagonal crystal system and has an ilmenite structure, the scintillation light yield is 16000 photons/M eV, the decay time is 5 [mu]s, and the energy resolution is 6.2%. The invention also provides a use of the Mg4Ta2O9 as a scintillation crystal material, and a preparation method of the Mg4Ta2O9. The preparation method comprises the following steps: MgO and Ta2O5 which are used as initial powders are uniformly mixed according to a molar ratio of 4.04:1, and are processed to form a raw material rod, the raw material rod is pre-sintered to obtain a pure-phase, dense and uniform polycrystalline rod, and the colorless and transparent rod-shaped crystal having a size of phi 4 mm * L 62 mm grows by adopting an optical floating zone technology. The method has the advantages of stable melting zone, simplicity in operation, effectiveness in inhibition of the volatilization of MgO, and maintenance of uniform composition and stable crystal quality.

A III-V group nitride system semiconductor self-standing substrate has III-V group nitride system semiconductor single crystal with a hexagonal crystal system crystalline structure. The substrate is provided with a polished surface at every position of which crystal orientation perpendicular to the substrate surface is inclined 0.09 degrees or more from the C-axis direction of the substrate.

The invention relates to compound chlorine boron barium silicate and chlorine boron barium silicate nonlinear optical crystal and a preparation method and use thereof. The compound chlorine boron barium silicate has the chemical formula of Ba7SiB3O13Cl and the molecular weight of 1265.35, and the compound chlorine boron barium silicate is synthesized by use of solid reaction process; the chlorine boron barium silicate nonlinear optical crystal has the chemical formula of Ba7SiB3O13Cl and the molecular weight of 1265.28, has a crystal structure belonging to hexagonal crystal system, and has the space group of P63mc, the unit cell parameters of a= 11.195(4), c = 7.263(6), Z = 2 and V = 788.3<3>. The crystal has a wide light transmitting range, and the powder frequency multiplication effect is 1 time of KDP (potassium dihydrogen phosphate). The chlorine boron barium silicate nonlinear optical crystal is grown by a high temperature melt method, is high in mechanical hardness and easy in cutting, polishing processing and preservation, and can be widely used in preparation of frequency doubling generators, upper frequency converters, lower frequency converters or optical parametric oscillators and other nonlinear optical devices.

The invention relates to single-phase nano layered ceramic power and a preparation method, in particular to nano layered Ta₂AIC ceramic power prepared by in-situ reaction and a preparation method. The nano layered Ta₂AIC ceramic belongs to a hexagonal crystal system, the space group is P6₃/mmc, the constant a of the unit cell crystal lattice is 3.08, and the constant c is 13.85. The nano layered Ta₂AIC ceramic is a good heat conductor and can be the reinforced phase of a metal matrix composite material as well as the weak interphase of a ceramic matrix composite material to increase tenacity. In the specific preparation method of the single-phase Ta₂AIC powder, tantalum powder, aluminium powder and graphite powder as materials are milled in a resin pot for five to thirty hours under a dry condition, are loaded into a graphite powder die for cold pressing shaping under the pressure of 5 to 20 Mpa after being sifted out and are thermally treated in a vacuum stove or a stove filled with argon, the temperature-raising speed rate is 5 to 20 DEG C per minute, the processing time under the temperature of 1500 to 1650 DEG C is twenty to one hundred and twenty minutes, and after the surface impurities of the cooled sample are removed and the cooled sample is broken up and sifted out, the powder is produced. The Ta₂AIC ceramic power prepared by the invention is characterized in high purity, small particle size and good uniformity.

The invention relates to a compound lead borate hydrate nonlinear optical crystal and a preparation method and use thereof. The crystal has a chemical molecular formula of Pb6B11O27H9, belongs to a hexagonal crystal system, has the space group of P32, has the molecular weight of 1803.182, and has the unit cell parameters that a is equal to 11.85 angstroms, b is equal to 11.85 angstroms, c is equal to 13.40 angstroms, and Z is equal to 3. The lead borate hydrate nonlinear optical crystal is obtained through hydrothermal reaction by adopting a hydrothermal method. The nonlinear optical effect of the crystal is 1.2 times that of a KDP crystal, the ultraviolet absorption cutoff edge is smaller than 190nm, and the transmission range in ultraviolet and visible regions is wide. A growth process of the crystal has the advantages of simplicity in operation, low cost, low used raw material toxicity, short growth cycle, stable physicochemical properties and the like. The nonlinear optical conversion crystal disclosed by the invention is extensively applied to nonlinear optical devices, such as frequency doubling converters and optical parametric oscillators.

The invention provides a laminated structure capable of obtaining an epsilon-phase gallium oxide semiconductor crystal membrane and a corresponding preparation method. The laminated structure mainly comprises a sapphire substrate and the epsilon-phase gallium oxide semiconductor crystal membrane. The laminated structure is prepared in a manner of depositing the epsilon-phase gallium oxide semiconductor crystal membrane on the sapphire substrate by use of chemical vapor deposition. The sapphire substrate is 100 to 1,000 [mu]m thick. The real surface of the sapphire substrate forms a deviation angle of 0 to 10 degrees with the crystal face c of the sapphire substrate. The gallium oxide semiconductor crystal membrane is epsilon-phase gallium oxide with a hexagonal crystal system and is 0.1 to100 [mu]m thick. According to the laminated structure and the corresponding preparation method, the problem of difficulty in preparation of a pure-phase epsilon-Ga2O3 crystal membrane is solved and anovel technical way is provided for preparation of a gallium oxide semiconductor material.

The invention provides a zinc oxide concentrate purifying technology. According to the technology, zinc oxide concentrate is dissolved with concentrated acid, impurities are purified and removed by a filtering method, and then, zinc ions in the solution are precipitated to obtain pure zinc oxide. The pure zinc oxide is dried, baked and calcinated to obtain zinc oxide powder. The zinc oxide product has pure-phase ZnO of a hexagonal crystal system wurtzite structure, does not have other impurities, and has relatively sharper diffraction peaks and excellent crystallinity.

The invention provides a ZnCo doped hexagonal crystal system W-type barium ferrite gyromagnetic material and a preparation method thereof. The chemical formula of the material is Ba (Zn1-xCOx) 2Fe16O27. The preparation method includes the steps: selecting BaCO3, ZnO, Co2O3 and Fe2O3 as raw materials and weighing components of the raw materials by calculation according to Ba (Zn1-xCOx) 2Fe16O27; grinding and pre-sintering all the raw materials, globules of a ball mill, large balls of the ball mill and water for the first time; grinding calcined materials, the globules of the ball mill, the large balls of the ball mill and the water for the second time, drying the grinded mixture, adding glue into the mixture, grinding the mixture into small particles and pressing the small particles into sample rings or sample wafers for measurement; heating the formed rings and the formed wafers, preserving heat in an air furnace, and hermetically calcining the formed rings and the formed wafers to prepare samples. The hexagonal crystal system W-type barium ferrite gyromagnetic material is prepared by an improved traditional oxide method, the method is stable and mechanical and more applicable to large-scale industrial production and popularization as compared with a sol-gel method, and stable gyromagnetic characteristics of the samples are obtained.

The invention provides a layered high-entropy MAX phase ceramic thermoelectric material and a preparation method thereof. A molecular formula of the layered high-entropy MAX phase ceramic thermoelectric material is Mn+1AXn, M is at least three elements selected from IIIB, IVB, VB and VIB group elements, A is at least one element selected from IIIA, IVA, VA and VIA group elements, X is a carbon element, and n is 1, 2 or 3. The layered high-entropy MAX phase ceramic thermoelectric material is advantaged in that an element ratio in the same position can be regulated and controlled according to actual requirements, the material has a hexagonal crystal system structure, the space group is P63/mmc, a crystal cell is formed by alternately stacking Mn+1Xn units and A-layer atoms in the c direction, and the high-entropy alloy is formed through the design of the combination of more than three M elements so that the high-entropy MAX-phase ceramic thermoelectric material has very wide applicationprospects in the fields of manned spaceflight, national defense war industry, automobile manufacturing, micro-nano electronics and the like, particularly in the fields of thermoelectric power generation, thermoelectric refrigeration and the like.

The invention relates to a substrate for epitaxial growth of semiconductor materials, in particular to a method for growing gallium nitride crystals by utilizing a coating silicon lining, wherein the coating silicon lining are bonded together by a silicon substrate and doping boron nitride slices through high pressure thermal treatment, the doping boron nitride slices comprise aluminum and high-melting metal doping hexagonal crystal system boron nitride nanosheets, and aluminum ions and high-melting metal ions are all inserted into a boron nitride laminated structure through a reaction of a co-rotating twin screw extruder. The method for growing the gallium nitride crystals by utilizing the coating silicon lining reduces lattice mismatch stress and thermal mismatching stress of the silicon lining and the gallium nitride crystals, reduces dislocation density gallium nitride (GaN) single crystals, obviously improves quality of GaN crystals, does not need to prepare gallium nitride base plates with special structures by adopting complex and expensive process, is simple in process, low in cost and low in growth temperature, and is suitable for volume production.

The invention discloses a magnetic aluminum nitride thin film material of a sphalerite structure and a preparation method and an application. In Sc-doped aluminum nitride, the crystal structure of the Sc-doped aluminum nitride is the sphalerite structure, and Sc elements occupy the position of part of Al elements in crystal lattice. The molar ratio of Sc to Al is 76:24. The molar ratio of the Al elements and the Sc elements to nitrogen elements is 1:1. The material prepared through the method is a diluted magnetic spin semiconductor material with sphalerite, the Curie temperature of the material of the sphalerite structure is high, the room temperature stability is good, and the spin injection efficiency is high; the crystal structure of reported diluted magnetic semiconductor GaN belongs to a hexagonal crystal system, the magnetism is weak and close to the super paramagnetic properties, and therefore application prospects are broad.