34 results about "Hexagonal crystal system" patented technology

The invention discloses a preparation method of a manganese-doped iron-based sulfide / nitrogen-doped reduced graphene oxide composite electrode material for a sodium-ion battery, a simple solvothermal method is combined with annealing treatment, and iron atoms in a hexagonal system are replaced by part of manganese atoms in a hydrothermal process to form multivalent iron-based sulfide, so that the composite electrode material is prepared. The manganese-doped iron-based sulfide / nitrogen-doped reduced graphene oxide composite electrode material for the sodium-ion battery is successfully prepared by uniformly compounding the manganese-doped iron-based sulfide and the nitrogen-doped reduced graphene oxide, and the manganese-doped iron-based sulfide / nitrogen-doped reduced graphene oxide composite electrode material can effectively regulate and control the electronic state density, reduce the sodium ion migration energy barrier and promote the electron / ion transmission; meanwhile, continuous growth of iron-based sulfide particles is limited, so that the iron-based sulfide particles are uniformly dispersed on the surface of the graphene, more active sites are exposed, the electrochemical reaction activity is improved, and the structural stability is enhanced. The composite electrode material disclosed by the invention can be widely applied to a negative plate for a sodium-ion battery, and has excellent adaptability and application prospect in a wide temperature range and under a high-current working condition.

The invention provides a sodium-ion battery positive electrode material as well as a preparation method and application thereof, and belongs to the technical field of sodium-ion batteries. The chemical formula of the positive electrode material is NamAxByCzFe (0.5-x-y) Mn (0.5-z) O2, m is 0.67-1.0, x + y is equal to 0.05-0.2, z is equal to 0.01-0.05, and A, B and C are different elements and are respectively selected from one of Li, Al, Mg, Si, Ti, Cr, Co, Ni, Cu, Zn, Zr and Sn. The positive electrode material is a P2-type ferro-manganese-based layered oxide, is a P2-phase hexagonal crystal system and contains a plurality of superlattice elements; according to the multiple superlattice elements, A, B and C atoms serve as centers, the peripheries of the A, B and C atoms are surrounded by six Mn atoms, and three honeycomb-shaped superlattice elements are formed in the crystal. The sodium ion layered positive electrode material provided by the invention is good in structural stability, high in capacity, good in cycling stability and excellent in rate capability.

The invention provides a chromium-titanium bimetallic layered sulfide positive electrode material and a preparation method and application thereof, and belongs to the technical field of lithium ion battery materials. The chemical general formula of the material is LiCrxTiyS2, x + y = 1, the material belongs to a hexagonal crystal system O1 type structure, and the space group is Pm1. Microtopography analysis shows that the material is granular, the particle size distribution is 2-15 [mu] m, the particle surface has a layered structure characteristic, and each element is uniformly distributed on the particle surface and in a bulk phase. The capacity of the material mainly comes from oxidation reduction between titanium and sulfur, and chromium has the effect of stabilizing a structural framework and does not participate in the charge compensation process. Electrochemical analysis shows that the reversible capacity of the LiCr2 / 3Ti1 / 3S2 positive electrode material reaches up to 223 mAh g <-1 > and is close to the theoretical value of the positive electrode material of the system. In addition, the material shows excellent rate capability and cycling stability, and still keeps the capacity retention ratio of 80% after 330 times of cycling.

The invention discloses a high-entropy O3 phase layered oxide material, a preparation method, application and a battery. The chemical formula of the material is Na < 1-x-y > Ca < y > Li Ni Cu < c > Fe < d > Co < e > Mn < f > Ti < g > O < 2 >, the material belongs to a hexagonal system, and the space group is R-3m; wherein 0 lt; x is less than or equal to 0.1, 0lt; a + b + c + d + e + f + g = 1, 0 < a < = 0.1, 0.15 < = b < = 0.3, 0 < c < = 0.1, 0.08 < = d < = 0.25, 0 < e < = 0.08, 0.3 < = f < = 0.5, and 0 < g < = 0.1. The high-entropy O3-phase layered oxide material prepared by the invention has relatively good structural stability and air stability, and the preparation method is simple and easy for large-scale production; the sodium ion battery formed by using the lithium ion battery positive electrode material as a positive electrode active material has the characteristics of high cycling stability, high rate capability and fast charge.

The invention relates to a graphite paper-based zinc negative electrode and a preparation method and application thereof, and belongs to the technical field of novel battery energy storage. The preparation method of the graphite paper-based zinc negative electrode comprises the following steps: by taking graphite paper as a negative electrode, a zinc foil as a positive electrode and a zinc salt aqueous solution as an electrolyte, carrying out electro-deposition by applying constant current, so that zinc ions are subjected to reduction reaction on the surface of the graphite paper to form a zinc deposition layer, and the graphite paper-based zinc negative electrode is obtained. The graphite paper substrate and a hexagonal crystal system of zinc have good lattice matching performance, and zinc can be induced to preferentially deposit along the (002) crystal face. The Zn (002) crystal face has higher electrochemical stability and lower interface energy, and dendritic crystal growth and side reaction are effectively inhibited. Compared with a traditional copper foil substrate, the surface of a zinc deposition layer of the graphite paper substrate is uniform and compact, is rich in metallic luster and has no obvious dendritic crystal protrusions.

The invention provides a two-dimensional material solar hydrogen production efficiency prediction method and device based on machine learning. The method comprises the following steps: reading a non-magnetic hexagonal crystal system single-layer material in a database to construct an initial data set; for samples with complete labels in the data set, training a single-layer material band edge position prediction model by adopting a feature engineering and gradient boosting decision tree algorithm; next, predicting and complementing samples with missing labels by using the trained model so as to generate a complete data set and further construct heterojunction double layers; carrying out data enhancement on a heterojunction sample of literature investigation through a CVAE-GAN hybrid architecture, and optimizing a feature vector; then training the new model by adopting a random forest algorithm to realize accurate prediction of the band edge position of the previously constructed heterojunction; and finally, the heterojunction type is judged in combination with a work function and a band edge position, the solar hydrogen production efficiency is calculated in batches by utilizing a program, and a high-efficiency heterojunction material is screened out.

The application discloses a low-frequency broadband seismic metamaterial filled with a five-mode dot array core and a design method thereof. The seismic metamaterial is composed of a five-mode dot array core, a concrete hollow pipe and an outermost soil layer. The five-mode dot array core is composed of a plurality of hexagonal crystal system units arranged periodically. The hexagonal crystal system unit is connected by an axial direction and is obtained by space structure conversion. The hexagonal crystal system unit is arranged periodically to form a three-dimensional dot array core structure composed of a plurality of hexagonal crystal system units. The low-frequency broadband seismic metamaterial filled with the five-mode dot array core can form a low-frequency broadband in a target frequency band. The seismic metamaterial is arranged in a vibration isolation area underground. When a seismic Rayleigh wave propagates to the area, the wave energy is significantly weakened under the action of a forbidden band, so that effective isolation and attenuation of the Rayleigh wave can be realized under the condition of a limited space.

This invention relates to a germanium-based chiral perovskite second-order nonlinear optical crystalline material, its preparation and application, wherein the chemical formula of the material is ( R -C7H 10 NO)GeI3 and ( S -C7H 10 NO)GeI3, where R -C7H 10 NO is a (R)-2-(1-hydroxyethyl)pyridine cation. S -C7H 10 NO is a (S)-2-(1-hydroxyethyl)pyridine cation. This crystal belongs to the hexagonal crystal system, space group [space group number missing]. P 63, cell parameters a =17.0~18.0 Å, b =17.0~18.0 Å, c =7.0~8.0 Å, unit cell volume V =2000~2200 Å 3 , α = β =90°, gamma =120° Z= 2. Under 1200 nm laser irradiation, the nonlinear optical crystal of the present invention ( R -C7H 10 NO)GeI3 and ( S -C7H 10 The frequency doubling effect of GeI3 powder is 15 times that of KH2PO4; under 2000 nm laser irradiation, the frequency doubling effect of the crystalline material powder is 1.0 times that of KTiOPO4, and both can achieve phase matching. The crystalline material also has a large birefringence, wherein ( R -C7H 10 NO)GeI3 is 0.518 @ 546 nm, ( S -C7H 10 The NO)GeI3 has a wavelength of 0.529 nm at 546 nm and a moderate optical band gap (2.68 eV). The crystalline material of this invention shows significant engineering application value in nonlinear optical applications such as near-infrared laser frequency conversion, optical parametric amplification, and electro-optic signal processing.

The application discloses a method for preparing hexagonal hydroxyl carbonate lanthanum by hydrothermal synthesis, which comprises the following steps: diluting lanthanum chloride solution as a bottom liquid with deionized water and adding lanthanum carbonate as a crystal seed in a precipitation reactor; adding a feed liquid and a precipitator into the precipitation reactor by using a parallel flow precipitation mode, generating lanthanum carbonate after precipitation reaction, controlling the input speed of the feed liquid and the precipitator to control the precipitation reaction time and adjust the pH value; taking out the precipitate lanthanum carbonate in the precipitation reactor, drying after filtration to obtain lanthanum carbonate as a precursor; adding the lanthanum carbonate and deionized water into a reactor to perform a hydrothermal synthesis reaction, washing the obtained final product with deionized water, and performing suction filtration or centrifugation to obtain a white solid; and placing the white solid in an oven, drying to obtain hexagonal hydroxyl carbonate lanthanum. The production process is simple, and the method is suitable for industrialized batch production of hexagonal hydroxyl carbonate lanthanum.

The invention relates to iron phosphate and a preparation method thereof, and a graded iron phosphate and lithium iron phosphate positive electrode material, the iron phosphate is hexagonal crystal system anhydrous iron phosphate, and the crystallinity is more than 98%; the particle size Dv10 of the iron phosphate is more than or equal to 0.5 mu m, the particle size Dv50 is 1.6 mu m-2 mu m, the particle size Dv90 is less than or equal to 5 mu m, and ((Dv90-Dv10) / Dv50) is less than or equal to 2.22; the tap density is 1g / cm < 3 >-1.2 g / cm < 3 >, the specific surface area is 1m < 2 > / g-3. 0m < 2 > / g, the atomic ratio of iron to phosphorus is 0.97 or above, and the sphericity is 0.806 or above; the iron phosphate is high in sphericity degree, high in dispersity among particles and easier to disperse in the lithium iron phosphate preparation process, and a better grading effect is formed; the iron phosphate is low in specific surface area, good in fluidity, easier to filter and not prone to agglomeration; the particle size of iron phosphate is small, so that the grading structure is more compact, and the method is suitable for preparing the high-pressure and high-energy-density lithium iron phosphate positive electrode material.

The application discloses a rare earth magnesium gallium sulfur bifunctional material, a crystal thereof, a preparation method and application. The material has a chemical formula of LnMg6Ga6S 16 , wherein Ln is Nd or Sm, is crystallized in a hexagonal crystal system, and has a space group of P-6; the unit cell parameters of NdMg6Ga6S 16 are a=b=16.6585 Å, c=7.4046 Å; the unit cell parameters of SmMg6Ga6S 16 are a=b=16.653 Å, c=3.702 Å. The material has nonlinear optical performance and near-infrared luminescence performance. The polycrystalline powder of the material can be prepared by a vacuum high-temperature solid phase reaction method, and the crystal can be grown by a high-temperature melt method or a crucible lowering method. The obtained crystal can be used for preparing nonlinear optical devices such as a laser frequency doubling generator, a frequency converter, an optical parametric oscillator or an optical parametric amplifier, and can also be used for preparing near-infrared luminescence devices such as a near-infrared luminescence diode or a near-infrared laser.

This invention relates to a series of alkali metal rare earth chalcogenides and a series of alkali metal rare earth chalcogenide nonlinear optical crystals, their preparation methods, and their applications. The general chemical formula for both the series of halides and the nonlinear optical crystals is A3Ln. 11 Ga 19 Q 45 X3, where A = K, Rb, Cs; Ln = La, Pr, Nd; Q = S, Se; X = Cl, Br, I, all belong to the hexagonal crystal system with space group and cell parameter Z = 1. This series of halides is synthesized using a high-temperature solid-state method, while this series of nonlinear optical crystals is grown using a high-temperature solution method or the Bridgman process. This material can be used to manufacture second harmonic generators, up- and down-frequency converters, optical parametric oscillators, etc.

The invention discloses an acetylene gas sensor, and belongs to the technical field of gas detection, the acetylene gas sensor is made based on a photonic crystal fiber, a gas hole structure in the photonic crystal fiber is formed by six large elliptical gas holes and a plurality of small circular gas holes, and the six elliptical gas holes and the plurality of circular gas holes are periodically arranged. A hexagonal lattice of a target lattice period is formed to restrain a transmission light field, on one hand, light field regulation and gas adsorption are optimized by utilizing anisotropy and large inner surface area of six large oval air holes, and the performance is improved; on the other hand, the actual operation difficulty of internal film coating and sensitive material coating processes is greatly reduced due to the large pore size, accurate control over the thickness of the nanogold film and the thickness of the acetylene gas sensitive film is facilitated, the manufacturing complexity of the acetylene gas sensor based on the photonic crystal fiber is reduced, and the yield is increased.

The application relates to a compound arsenic-silicon-gallium-strontium and an infrared nonlinear optical crystal of arsenic-silicon-gallium-strontium, a preparation method and application, the compound has a molecular formula of SrGa3Si4As 11 , a molecular weight of 1233.26 g / mol, an asymmetric center, and is crystallized in a hexagonal crystal system P , a 63 space group, a cell parameter of a=b=9.2604(3) A, c=11.6484(5) A, Z=2, and V=865.08(7) A 3 , and is prepared into a crystal by using a high-temperature melt method, a chemical vapor phase transmission method or a flux method. The crystal has strong laser damage resistance, large nonlinear optical effect, wide infrared transmission range, and simultaneously has the advantages of large hardness, good mechanical property, not easy to break and deliquesce, easy to process and store and the like, and can be used for manufacturing infrared nonlinear optical devices.

This invention provides a three-dimensional covalent organic framework material, its preparation method, and its applications. The material is constructed by the condensation of biphenyl-3,3',5,5'-tetraaldehyde and p-phenylenediamine via imine bonds; it possesses a hexagonal crystal system, P6 space group, and a qtz topology with triple interpenetrating atom (AA) packing, and a BET specific surface area of ​​1408 m². 2 The material exhibits a high adsorption capacity ( / g), thermal stability up to 410℃; and at 298 K and 1.0 bar, it achieves an adsorption capacity of 18.8 mmol / g for pure NO2, 7.41 mmol / g for pure SO2, and 5.52 mmol / g for pure NH3. It can deeply purify 2500 ppm NO2 / SO2 to <0.1 ppm, with an NO2 / SO2 selectivity >5000. Under humid conditions, its NO2 capture efficiency not only does not significantly decrease but also shows a certain degree of improvement. Cyclic tests of the material's NO2 enrichment and conversion show excellent capture and conversion effects over three cycles, effectively converting captured NO2 into nitric acid. With its extremely high NO2 / SO2 / NH3 adsorption capacity, selectivity, and stability, it is suitable for the efficient capture and deep purification of toxic gases in the atmosphere.

The present application relates to the technical field of nano energy storage material preparation, and particularly relates to a two-dimensional molybdenum nitride and crystalline Mo2N nanosheet ammonia-free preparation method. A two-dimensional molybdenum boride compound derived from a rare earth molybdenum aluminum boride compound is used as a precursor to prepare two-dimensional molybdenum nitride and crystalline Mo2N nanosheet with a six-fold symmetric layered structure under an ammonia-free condition. A compound with a hexagonal crystal system formed by metal molybdenum, heavy rare earth metal, metal aluminum and boron is used as a precursor. After wet etching of an aluminum atom layer and a rare earth atom in the compound by using a fluorine-containing acid solution, intercalation and exfoliation are performed to form a two-dimensional derivative with a certain energy storage density. The two-dimensional derivative is annealed at different temperatures under nitrogen to control the atomic layer spacing, surface chemical state, surface functional group and chemical bond in the two-dimensional derivative, realize in-situ conversion from the two-dimensional molybdenum boride to the two-dimensional molybdenum nitride and crystalline Mo2N with a six-fold symmetric layered structure, and significantly improve the specific capacitance.

The invention discloses application of a hexagonal crystal system material GdAl3 (BO3) 4 in the field of extremely low temperature magnetic refrigeration, and relates to the technical field of magnetic refrigeration materials. The hexagonal crystal system material GdAl3 (BO3) 4 applied to the field of extremely low temperature magnetic refrigeration, provided by the invention, can show excellent magnetocaloric performance and stability under the condition of extremely low temperature (less than or equal to 300mK). According to the material, Gd < 3 + > is introduced as magnetic ions, Al < 3 + >, borate ions and other ions with small relative molecular mass are introduced as ligands, the mass ratio of the magnetic ions is guaranteed, and the material has a higher magnetic entropy change value. The phase change temperature is low, no phase change occurs at the temperature of 300 mK or above, lambda phase change occurs at the temperature of 300 mK, and the magnetic entropy is well reserved in an extremely low temperature region. Crystal water is not contained, and the structural stability and thermal stability are high. The magnetic refrigeration device has a remarkable magnetothermal effect in an extremely low temperature region, and can realize efficient, stable and convenient magnetic refrigeration application in sub-Kelvin or even lower temperature regions.

The invention discloses a bimetallic MXene TiVCTx / Fe3O4 composite material as well as a preparation method and application thereof, and belongs to the field of electromagnetic wave absorbing materials. The invention aims to solve the problem that the existing MXene cannot meet the requirements of thin thickness, wide bandwidth and low reflection loss of a new electromagnetic wave absorber. The diameter of Fe3O4 is 30nm, the Fe3O4 is stably loaded on a TiVCTx nanosheet, a TiVCTx crystal structure is a hexagonal crystal system structure (space group P63 / mmc), and the sheet diameter of the TiVCTx nanosheet is 5 + / -2 [mu] m. Compared with common Ti3C2Tx, the introduction of V causes lattice distortion and forms a defect which can be used as a polarization center in MXene, changes the distribution of charges around metal atoms, forms a local electric field, generates a large number of dipoles, and greatly enhances the polarization loss of the material. The fabric has good electromagnetic wave absorption performance.

The application belongs to the field of covalent organic framework materials, and particularly relates to synthesis of a compound, a covalent organic framework material containing bimetal units, a preparation method and use thereof. The structural unit belongs to a hexagonal crystal system P3 space group, and cell parameters are alpha=90°, beta=90°, gamma=120°. Due to the uniqueness of the material structure, the material can be used as a photocatalyst, and can directly perform a gas-liquid catalytic reaction under visible light driving to reduce carbon dioxide into carbon monoxide, with a yield of 320 micromoles per gram ‑1 , and an average of 64 micromoles per gram ‑1 h ‑1 per hour.

This invention discloses a phosphorus compound, its nonlinear optical crystal, its preparation method, and its uses. The phosphorus-silicon-gallium-calcium compound and the phosphorus-silicon-aluminum-calcium compound of this invention can both be prepared using a high-temperature solid-state method. The phosphorus-silicon-gallium-calcium nonlinear optical crystal of this invention is CaGa3Si4P. 11 Phosphorus-silicon-aluminum-calcium nonlinear optical crystal CaAl3Si4P 11 Both belong to the hexagonal crystal system. The nonlinear optical crystals of phosphorus silicon gallium calcium and phosphorus silicon aluminum calcium of the present invention have large nonlinear optical effects (the frequency doubling output intensity is about 3.1 and 2.9 times that of AgGaS2 under the same conditions, respectively), wide optical band gap (2.41-2.49 eV), good infrared transmission performance in the 2.510 micrometer band, large nonlinear optical effects, good mechanical properties, and easy processing. They can be widely used in various nonlinear optical fields and the mid-infrared band.

This invention relates to the compounds strontium lanthanum chloroborate and barium lanthanum chloroborate, as well as nonlinear optical crystals of strontium lanthanum chloroborate and barium lanthanum chloroborate, their preparation methods, and their uses. The general chemical formula for both the compounds and crystals is A3La4B3O. 13 Cl, where A = Sr, Ba, space group P63, belongs to the hexagonal crystal system, and cell parameter Z = 2. The compounds lanthanum strontium chloroborate and lanthanum barium chloroborate are synthesized by a solid-state reaction method. The nonlinear optical crystals of lanthanum strontium chloroborate and lanthanum barium chloroborate are grown using a high-temperature melt method. This material can be used to manufacture second harmonic generators, up-down frequency converters, optical parametric oscillators, etc.

The invention belongs to the field of covalent organic framework materials, and particularly relates to a preparation method and application of a covalent organic framework material. The material is characterized in that a structural unit belongs to a hexagonal crystal system P6 space group, and cell parameters alpha = 90 degrees, beta = 90 degrees and gamma = 120 degrees. Due to the uniqueness of the material structure, the material can be used as a photocatalyst, a gas-liquid catalytic reaction is directly carried out under the driving of visible light, and the average yield of the reduction product hydrogen peroxide is 1980 micromoles / g <-1 > per hour.

The invention discloses a preparation method of polyester based on a tetragonal system germanium dioxide catalyst. The preparation method comprises the following steps: binary acid and dihydric alcohol are taken as raw materials, esterification and polycondensation reaction are carried out in the presence of a catalyst, the catalyst adopted in the polycondensation reaction is tetragonal crystal system germanium dioxide, and the tetragonal crystal system germanium dioxide is synthesized by a hydrothermal method, has more oxygen vacancies and higher catalytic activity than traditional hexagonal crystal system germanium dioxide. The method provided by the invention can efficiently catalyze and synthesize PET. The obtained polyester product has high intrinsic viscosity, high light transmittance, low yellowness and excellent thermal stability, and the comprehensive performance of the polyester product is obviously superior to that of a product prepared by adopting a hexagonal crystal system germanium dioxide catalyst. The method is particularly suitable for producing high-end optical-grade polyester materials.

The invention discloses a magnetic refrigeration material, a preparation method thereof and application of the magnetic refrigeration material in magnetic refrigeration in an extremely low temperature region. The chemical formula of the magnetic refrigeration material is Gd5 (C3N3O3) (OH) 12, the magnetic refrigeration material belongs to a hexagonal system, the space group is # imgabs 0 #, the cell parameter is # imgabs 1 #, the magnetic refrigeration material has relatively high magnetization intensity and a high-thermal-stability magnetic structure, and still shows superparamagnetic characteristics without magnetic phase change at extremely low temperature, and when the temperature T of the material is 2K and the applied magnetic field delta H is 7T, the maximum magnetic entropy change-delta Sm is 58.1 J * kg <-1 > * K <-1 >, and the maximum magnetic entropy change-delta Sm is 58.1 J * kg <-1 > * K <-1 >. The material is an ideal magnetic refrigeration material in an extremely low temperature region.

The invention relates to a calcium-doped phase composite high-temperature thermistor material and a preparation method thereof. The chemical formula of the phase composite high-temperature thermistor material is 0.7 Y2O3-0.3 CaxY (1-x) Cr0. 5Mn0. 5O3 (x is more than or equal to 0 and less than or equal to 0.5), the structure of the phase composite high-temperature thermistor material is a composite structure of a wurtzite structure high-resistance phase Y2O3 of a hexagonal system and a perovskite structure low-resistance phase CaxY < 1-x > Cr < 0.5 > Mn < 0.5 > O < 3 >. Compared with the prior art, the material has obvious negative temperature resistance coefficient characteristics in the temperature range of 25-500 DEG C, the material constant is B25 DEG C / 500 DEG C = 2930K-3890K, the resistivity is 1.67 * 10 < 4 >-2.26 * 10 < 5 > omegacm at the temperature of 25 DEG C, the electrical property of the material system is stable, the linearity of the lnrho-1 / T relation of the temperature resistance characteristic of the material is good, and the material is suitable for manufacturing high-temperature thermistors.

Provided are composite tungsten oxide particles which contain a composite tungsten oxide represented by general formula MxWyOz (0.20 < = x / y < = 0.37, 2.2 < = z / y < = 3.3) and having a hexagonal crystal system, and which are obtained by dispersing the composite tungsten oxide particles in a dispersion liquid of a liquid medium, or in a molar absorption coefficient curve in the range of 0.5 eV to 2.0 eV of a dispersion in which the composite tungsten oxide particles are dispersed in a solid medium, the peak value of an absorption curve in which surface plasma absorption exists locally in an orientation parallel to the c-axis of the composite tungsten oxide crystals contained in the composite tungsten oxide particles is less than the peak value of an absorption curve in which surface plasma absorption exists locally in the orientation parallel to the c-axis of the composite tungsten oxide crystals contained in the composite tungsten oxide particles. And the peak value of the absorption curve of polaron absorption is low.

The invention provides a server case, a composite material of the server case, a forming method, equipment and a medium, and an aluminum-based composite material comprises the following components in percentage by mass: 3-5% of ceramic nanoparticles, 2-4% of a hexagonal crystal system flaky material, 0.5-1% of rare earth oxide and the balance of an aluminum matrix. The ceramic nanoparticles, the hexagonal system flaky material and the rare earth oxide are reasonably proportioned, so that the comprehensive performance of the aluminum-based composite material is improved, the ceramic nanoparticles enhance the mechanical strength, the hexagonal system flaky material optimizes a heat conduction path, and the rare earth oxide improves the interface bonding strength of a reinforced phase and an aluminum matrix; according to the method, a collaborative strategy of three-dimensional modeling, thermal field simulation, truss structure design and partition printing is adopted, partition and customization of truss lattice parameters are carried out according to the internal heat flux density of the case, corresponding printing process parameters are matched, and performance optimization of a bearing area and a heat dissipation area is achieved; through collaborative innovation of materials and the process, the mechanical property, the heat dissipation performance and the overall light weight level of the case are improved.

This invention discloses a room-temperature negatively expanding Laves phase intermetallic compound, its preparation, and its applications. The chemical formula of this room-temperature negatively expanding Laves phase intermetallic compound is Hf. x ,Ta a‑ x Nb b Fe2+, where 0.8525≤x≤0.875, 0.94≤a≤0.95, 0.05≤a≤0.06, has a hexagonal crystal system with space group P63 / mmc. It exhibits negative expansion characteristics in the temperature range of 219K~325K, with a linear expansion coefficient α. l ≤23×10 ‑6 K ‑1 This invention enhances negative expansion by introducing Ta into Hf-Fe2Laves metal and effectively broadens its negative expansion temperature range by introducing Nb. The synthesis method of this invention is simple and easy to implement, and it can be combined with positive expansion materials to achieve zero thermal expansion of the composite material at room temperature, thus possessing potential for room temperature applications.

The invention belongs to the technical field of magnetic refrigeration materials, and particularly relates to a rare earth chloride borate magnetic refrigeration material, a preparation method thereof and application of the rare earth chloride borate magnetic refrigeration material in magnetic refrigeration. The chemical formula of the rare earth chloride borate magnetic refrigeration material is Eu5RE (III) (BO3) 4Cl, metal RE is Eu, Gd, Tb, Dy, Ho, Er or Tm and belongs to a hexagonal crystal system, and the space group is P63mc. The rare earth chloride borate magnetic refrigeration material has a magnetothermal effect with low magnetic field drive near the temperature of liquid helium, the maximum magnetic entropy change of the rare earth chloride borate magnetic refrigeration material is larger than or equal to 19.6 J.kg <-1 >. K <-1 > at the temperature of 2.5 K when the magnetic field change is 0-1 T, the maximum magnetic entropy change of the rare earth chloride borate magnetic refrigeration material is larger than or equal to 31.7 J.kg <-1 >. K <-1 > at the temperature of 3.5 K when the magnetic field change is 0-2 T, and the maximum magnetic entropy change of the rare earth chloride borate magnetic refrigeration material is larger than or equal to 31.7 J.kg <-1 >. K <-1 >. The maximum magnetic entropy change is greater than or equal to 52.0 J.kg <-1 >. K <-1 > when the magnetic field change is 0-5 T at the temperature of 3.5 K, the magnetic refrigeration material is obviously superior to many disclosed magnetic refrigeration materials at present, and the magnetic refrigeration material is expected to be applied to a liquid helium temperature region magnetic refrigeration technology on the basis that the magnetic refrigeration material shows excellent magnetocaloric performance near the liquid helium temperature.

The present invention relates to a preparation method and application of a compound of lanthanum magnesium aluminum sulfide and lanthanum magnesium aluminum sulfide phosphor. The molecular formula of the compound is LaMg6Al6S 16 , the molecular weight is 958.22, the unit cell parameters are prepared by high temperature solid phase method, the sulfur aluminum magnesium lanthanum phosphor, the molecular formula is LaMg6Al6S 16 The structure belongs to the hexagonal crystal system, the space group is , and the unit cell parameter is . The phosphor prepared by the method of the present invention has good crystallinity, high luminous efficiency, strong brightness, stable chemical properties, and long life. The method is simple and easy to implement, has a wide process window, and is suitable for large-scale industrial production.