2740 results about "Crystal structure" patented technology

The invention discloses a catalyst used for preparing acrylic acid and butyl ester by the dehydration of butyl lactate and a preparation method thereof. The catalyst is a composite catalyst, comprising a main catalyst A and auxiliary catalysts B, C, D and E, wherein, A is calcium sulphate, B is sulphuric acid, C is phosphate, D is alkaline matter and E is promoter. The preparation method comprises the steps as follows: five compositions A, B, C, D and E are sufficiently mixed, baked for 2-10 hours at the temperature of 200-800DEG C and formed for standby. The catalyst has high catalytic activation; under the catalysis of the catalyst, the molar yield reaches 75.1 percent and the molar selectivity of the acrylic acid and butyl ester reaches 71.5 percent. The preparation method has the advantages that the crystal structure of the main catalyst can be improved so as to be beneficial for carrying out the reaction; and the introduction of different auxiliary catalysts and quantities is helpful to improve the conversion ratio of the raw material and the product selectivity and is beneficial for improving the strength of the catalyst.

The invention discloses a high-purity quartz sand reinforced chlorination purification method, and belongs to the technical field of inorganic non-metallic material processing. The method comprises the following steps: putting a quartz sand raw material containing crystal structure impurities into a roasting furnace, and synchronously introducing a gas chlorinating agent and a gas reducing agent into the roasting furnace for roasting to obtain purified quartz sand. According to the method, on the basis of conventional chloridizing roasting purification, a gas reducing agent is introduced to regulate and control the reaction atmosphere, efficient dissociation and chlorination of crystal structure impurities difficult to remove are promoted, and deep efficient purification of quartz sand is achieved. The method has the advantages of simple process equipment, high raw material applicability, high impurity removal efficiency and the like, and can be widely applied to production of 4N5-grade and above high-purity quartz sand.

The invention provides a piezoelectric device and a preparation method thereof. The piezoelectric device comprises a substrate material layer; the single crystal seed layer is arranged on the substrate material layer, and the single crystal seed layer is made of a six-membered ring structure carbon material; the electrode layer is arranged on the single crystal seed layer; and the single crystal piezoelectric film is arranged on the electrode layer. According to the preparation method of the piezoelectric device, the cost is lower, the material price is lower, the film deposition efficiency is higher, and the crystal structure of the single crystal piezoelectric film is more stable.

The invention provides a multi-dimensional adsorbent performance evaluation method, and belongs to the technical field of performance evaluation, and the method comprises the following steps: carrying out a first test on an adsorbent, recording the mass change of the adsorbent after each cycle, and evaluating the adsorption performance of the adsorbent to obtain a first test result; and carrying out a second test on the adsorbent to determine the anti-sintering capability and the cycling stability of the adsorbent so as to obtain a second test result. Microscopic form change, influence condition and crystal structure of the adsorbent before and after the test are observed, and microscopic characterization of the adsorbent is obtained. And performing multi-scale simulation on the adsorbent according to the microscopic representation, and performing life cycle evaluation on the adsorbent by using a simulation result to obtain a life cycle evaluation result. And an optimization direction is provided for comprehensive performance evaluation of the adsorbent. The invention aims to realize an efficient and low-cost carbon capture technology and promote effective utilization of solid waste resources, and provides a systematic evaluation method to promote the development of the carbon capture technology.

The invention belongs to the technical field of superfine tungsten powder, and particularly relates to superfine tungsten powder and a preparation method thereof.The preparation method includes the steps that an ammonium tungstate solution, hydrochloric acid and carbon black serve as raw materials to prepare a mixture of tungstic acid and a carbon precursor; calcining the tungstic acid and carbon precursor mixture in a nitrogen atmosphere to obtain a tungsten oxide and carbon mixture; a tungsten oxide and carbon mixture is calcined in an argon atmosphere, the argon atmosphere is kept for natural cooling, the superfine tungsten powder is obtained, the superfine tungsten powder is uniform in dispersion, complete in grain development, smooth in surface, free of pores and complex in morphology, the crystal structure of the superfine tungsten powder is a body-centered cube, the average particle size is smaller than or equal to 0.7 micrometer, and the specific surface area is smaller than or equal to 1.0 m < 2 > / g.

The invention provides a solid electrolyte material screening method based on a physical constraint diagram attention network, and the method comprises the steps: calculating an ionic conductivity parameter corresponding to a solid electrolyte material through dynamic Monte Carlo simulation, and constructing an initial data set containing a mapping relation between a crystal structure and ionic conductivity; constructing a physical constraint graph attention network prediction model; performing iterative training and hyper-parameter adjustment on the physical constraint graph attention network prediction model by adopting the initial data set based on cross validation and Bayesian optimization to obtain an optimal physical constraint graph attention network prediction model; a novel crystal structure is generated through a generative large language model, and a candidate material data set is constructed; and taking the candidate material data set as input, utilizing the optimal physical constraint diagram attention network prediction model to predict the ionic conductivity of the material, and screening to obtain the solid electrolyte material with high ionic conductivity. The method breaks through the inherent mode that a traditional prediction method is limited to known materials, the material exploration space is greatly expanded, and development of solid electrolyte key materials is accelerated.

The invention discloses a reverse design method applied to a solid electrolyte material. The method comprises the following steps: firstly, constructing an inorganic solid electrolyte material field knowledge base; generating a chemical formula conforming to physical and chemical rationality through a chemical formula generator based on guidance of a domain knowledge base; based on the generated chemical formula, further utilizing a large language model to generate a candidate crystal structure information file, and performing optimization in combination with a Monte Carlo tree search method; in the optimization process, in order to evaluate the performance of the generated candidate crystal structure, a graph neural network model driven by domain knowledge is cooperated to carry out multi-target performance prediction, a prediction result is used as reward feedback, and then the generation quality of the candidate crystal structure is optimized; and finally, by taking activation energy and convex hull energy as indexes, screening out a potential novel inorganic solid electrolyte material meeting performance requirements. The development efficiency of the inorganic solid electrolyte material is improved.

Provided are: a crystalline sulfide solid electrolyte, which has an improved ionic conductivity while adopting a liquid phase method, contains predetermined atoms, has a diffraction peak in X-ray diffractometry using a predetermined CuKα ray, and has a thio-LISICON Region II-type crystal structure as a basic structure; and a method for producing a crystalline sulfide solid electrolyte, the method including mixing using predetermined complexing agents and an instant drying step.

The present invention discloses an amorphous curcumin nanoparticle and its preparation method and application. In the present invention, an absolute ethanol solution of curcumin and apple polyphenol is dropped into water under stirring, and then left standing for treatment to remove ethanol and adjust the pH to obtain amorphous curcumin nanoparticles. Through the bottom-up antisolvent precipitation method and the interaction between curcumin and polyphenol, and by optimizing the important conditions in the preparation process, the present invention effectively reduces the particle size of curcumin and transforms its crystal structure into an amorphous structure. At the same time, the amorphous curcumin nanoparticles can be used as an emulsifier for Pickering emulsions to prepare curcumin emulsions. Compared with curcumin nanoparticles, the curcumin emulsions have higher stability. The present invention has low energy consumption, reduced particle size, can improve solubility, enhance its bioavailability, improve its emulsifying properties, and has good application prospects.

The invention discloses an application of a molybdenum disulfide-based piezoelectric catalytic material in a seawater uranium extraction material, and relates to the technical field of seawater uranium extraction, thiourea and sodium molybdate are used as precursors, and a MoS2 nanoflower with a specific 1T / 2H composite crystal structure is constructed through a hydrothermal synthesis technology. The method is placed in a uranyl nitrate solution, ultrasonic treatment is combined, efficient extraction of uranium can be achieved, and the method has potential application to extraction of uranium from seawater. The method is simple in process and environment-friendly, almost does not generate harmful waste in the synthesis process, does not need complex operation, and has good amplification preparation potential.

The invention discloses a sodium ferric pyrophosphate material with a sodium storage dominant crystal face regulated and controlled by cation doping as well as a preparation method and application of the sodium ferric pyrophosphate material. The chemical formula of the prepared sodium ferric pyrophosphate material with the regulated and controlled crystal structure is Na < 4 > Fe < 2.97 > M < 0.03 > (PO4) < 2 > P < 2 > O < 7 >. Wherein M = Sr, or Sr and a second doping element, and the second doping element is selected from one of Cd, Bi, Mo, Ni and Al. The material is prepared by adopting a sol-gel method, an iron source, a chelating agent, a sodium source, a phosphorus source and doping elements are dissolved in deionized water, and stirring is performed until a gel state is formed; and drying and calcining twice to obtain a final product. The sodium ferric pyrophosphate electrode material prepared by the invention has more sodium storage dominant crystal faces, shows good electrochemical performance, has the advantages of simple preparation process, easily available raw materials and low cost, has remarkable industrial application value, and is easy for large-scale production.

The invention provides a metal ore artificial intelligence sorting method based on lithofacies analysis, and relates to the technical field of data processing, and the method comprises the steps: obtaining a unified image of an ore sample, extracting a crystal structure contour, and calculating texture direction consistency, particle distribution density and color concentration degree in each region; constructing a lithofacies analysis model based on a two-channel neural network; training the lithofacies analysis model according to the training data set to obtain a fusion recognition model; obtaining an ore image to be sorted, and inputting the ore image to be sorted into the fusion recognition model to obtain predicted mineral distribution data; and extracting a boundary confidence factor and a region type probability, carrying out re-calibration on predicted mineral distribution data, generating a sorting control instruction, and driving sorting equipment to carry out physical sorting operation. The rock facies analysis is carried out on the ore image sample through artificial intelligence, and the types of symbiotic minerals can be accurately distinguished.

The invention discloses a powder metal particle removing system and method, and the method comprises the steps that powder is transferred into a preset container; mixing the powder materials in the container; putting the mixed powder into a sagger, and sintering to form a crystal structure; the sintered crystal structure is crushed and ground to the required particle size; and metal particles in the crushed particles are subjected to microwave oxidation. According to the scheme provided by the invention, after the powder is transferred into the preset container to be mixed, the powder is sintered in the sagger, then the sintered powder is ground, and finally the ground powder is subjected to microwave heating by utilizing the microwave oxidizer. After the microwave irradiates the powder, the metal particles contained in the powder can be quickly oxidized, the heating speed is high, the efficiency is high, the corresponding metal particles can be effectively removed, and the removal efficiency is high.

The invention relates to the technical field of electrochemistry, and provides a sulfide solid electrolyte, a preparation method thereof, a battery and application. The chemical formula of the sulfide solid electrolyte is Li7-aPS6-aXa, X is halogen, and a is greater than or equal to 1 and less than or equal to 2; wherein the peak area of a diffraction peak corresponding to a (111) crystal plane of the sulfide solid electrolyte is I1, the peak area of a diffraction peak corresponding to a (311) crystal plane of the sulfide solid electrolyte is I2, and I1 / I2 is larger than or equal to 0.2 and smaller than or equal to 0.3. The I1 / I2 of the sulfide solid electrolyte disclosed by the invention is within the range, a good crystal structure and a relatively large interface area can be provided, and ion movement is promoted, so that relatively high ionic conductivity is obtained. Furthermore, according to the method disclosed by the invention, the high ionic conductivity of the product is ensured by reducing the solvent dosage and optimizing the sintering step, and meanwhile, the environmental pollution, the energy consumption and the production cost are remarkably reduced.

The invention relates to the technical field of zero-crystallization silicon quartz stone production, in particular to an artificial environment-friendly zero-crystallization silicon quartz stone forming process and manufacturing equipment thereof. The invention discloses a forming process of artificial environment-friendly zero-crystalline silicon quartz stone. The forming process comprises the following steps: heating silica-containing quartz sand and quartz powder to a molten state (gt); then adding glass sand and glass powder, completely melting the glass sand and the glass powder, conveying the glass sand and the glass powder into a cooling kettle, rapidly cooling the glass sand and the glass powder so as to destroy a crystal structure to generate an amorphous quartz block, grinding the amorphous quartz block into amorphous quartz powder and / or sand by utilizing a grinding kettle, mixing the amorphous quartz powder and / or sand with unsaturated resin, a curing agent, a dispersing agent, a coupling agent and water, pressing and curing to obtain a finished product. The artificial environment-friendly zero-crystal silicon quartz stone is obtained, so that silicosis caused by inhalation of silicon dioxide dust by workers in the processing process of the quartz stone plate is effectively reduced.

Provided are a polariton device, a polariton system, a method of manufacturing the polariton device, and a method of controlling the polariton device. The polariton device includes a cavity including a gain layer including a ferroic material that undergoes a phase transition into an asymmetrical crystal structure in response to an external stimulus, an upper reflective layer formed on top of the cavity, a lower reflective layer formed below the cavity, and a Rabi frequency controller configured to control a Rabi frequency of the polariton device by providing a stimulus to the gain layer.

The invention discloses a structure evolution method and system for phase change recrystallization coupling of a multiphase metal material, the orientation during martensite generation is calculated through martensite crystallography, martensite growth is carried out, and then the martensite phase change result of the material in a multiphase state is predicted through a metallographic structure determination method. The method is established by utilizing a geometrical relationship between different crystal structures of alpha and beta titanium during martensite phase transformation of the titanium alloy, so that the method can be suitable for predicting martensite phase transformation and dynamic recrystallization coupling of the two-phase titanium alloy. The method can be used for predicting the proportion of martensite phases generated in the actual production process of titanium alloys of different marks, further predicts the surface performance, can remarkably reduce the cost and improve the simulation and analysis efficiency in the actual industrial production, and has important significance on computer-aided analysis and design in the part machining deformation process.

The invention relates to a design method of a novel crystal structure based on a large language model, and belongs to the crossing field of artificial intelligence and material science. According to the design method, design requirements are recognized through a large language model, a first crystal design constraint is extracted, then an example crystal structure is retrieved from a crystal structure database, a second crystal design constraint is output, and the large language model learns the example structure and generates a first target crystal structure according to the second crystal design constraint. The structure is determined as a second target crystal structure after being checked, then the second target crystal structure is subjected to structural relaxation to obtain a candidate structure set, and the novel crystal structure is obtained through stability screening. According to the design method, dependence on large-scale training can be effectively eliminated, novel crystal structure discovery without additional training is realized, adaptive conversion oriented to diversified novel crystal discovery scenes is realized, a design target is automatically analyzed according to different user intentions and crystal generation task types, and a generation strategy is flexibly adjusted.

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for predicting crystal structures. One of the methods includes providing an indication of the one or more molecules; generating a set of crystal structures based on the indication; generating a reliability metric of a machine learning model for generating a property metric for each crystal structure in the set of crystal structures; calculating the property metric for each crystal structure in the set of crystal structures to generate a set of property metrics, by (i) using the machine learning model if the reliability metric for the crystal structure is within a predetermined threshold, and (ii) using a ground truth calculation of the crystal structure if the reliability metric for the crystal structure is not within the predetermined threshold; and taking an action based on the set of crystal structure indications for the one or more molecules, wherein the set of crystal structure indications is based on the set of crystal structures and the set of property metrics.

The invention relates to the technical field of machine learning potential molecular simulation, and provides a montmorillonite thermal conductivity prediction method based on NEP machine learning potential, and the method comprises the following steps: constructing a montmorillonite crystal structure model, carrying out first principle molecular dynamics calculation on the montmorillonite crystal structure model, introducing lattice distortion and atomic disturbance, and generating an initial structure set; performing static single-point DFT calculation on the initial structure set, and constructing a training data set; based on an NEP machine learning framework, utilizing the training data set to train and generate a potential function; optimizing the generation process of the potential function by adopting an active learning strategy; and performing thermal conductivity prediction verification on the potential function, and obtaining a thermal conductivity prediction result of the montmorillonite based on the potential function passing the verification. The defect that a traditional classical potential function depends on an empirical or semi-empirical model and is limited in precision and applicability is overcome, the problem that the dynamic behavior and the heat conduction mechanism of a complex material are difficult to accurately capture is solved, the calculation cost is reduced, and meanwhile the precision is kept.

The invention belongs to the field of computational chemistry, and particularly relates to a multi-parameter collaborative dynamic screening method for adsorbed species on the surface of a catalyst. Comprising the following steps that an initial crystal structure is constructed and optimized through VESTA software, and a stable crystal structure model is obtained through density functional theory optimization; integrating working condition parameters such as a solvent, pH and potential, and drawing a Bayer diagram to label adsorption species and a mapping relation; and calculating a zero charge point and capacitance to obtain electrochemical parameters, and determining stable adsorption species under actual reaction through constant potential molecular dynamics simulation. According to the scheme, a deep structure-activity relationship between an active site structure and catalytic activity under a working condition is established through integration of all working condition parameters, labeling of adsorption species by a Boubye diagram, constant potential molecular dynamics simulation and the like; the problems that a systematic method combined with actual working condition parameters is lacked in prediction of the adsorbed substances on the surface of the catalyst, and real adsorbed species are difficult to accurately screen are solved, and accurate capture and efficient screening are achieved.

The invention discloses an optical coherence tomography detection method for aero-engine thermal growth oxides, and relates to the field of optical detection. The method comprises the following steps: acquiring interference signals of a reference light field and a sample scattering light field, and performing adaptive polarization state compensation on the interference signals based on a dynamic polarization matching factor to obtain compensated interference signals; anisotropic filtering is carried out on the compensation interference signal, oxide layer columnar crystal structure features are separated, and a filtering signal is obtained; performing time-frequency joint analysis on the filtering signal, optimizing a time-frequency transformation kernel parameter by using an adaptive window width adjustment factor, and extracting oxide layer thickness and frequency band energy distribution; and fusing the columnar crystal structure characteristics and the frequency band energy distribution, constructing a cross-scale thermodynamic inversion model, and outputting a prediction result of the residual life of the thermal growth oxide layer of the engine. By introducing polarization compensation, frequency domain analysis optimization and a multi-field coupling inversion model, the imaging definition, the thickness extraction precision and the residual life prediction capability of the thermal growth oxide layer are remarkably improved.

The invention belongs to the technical field of energy materials, and provides a multi-functional-layer lithium manganate positive electrode material and a preparation method thereof and a lithium battery, the multi-functional-layer lithium manganate positive electrode material comprises a core body and a coating layer, the core body sequentially comprises a bulk-phase-doped lithium manganate matrix, an induction doping layer and a modification doping layer from inside to outside, the chemical general formula of the core body is Li < 1 + a > Mn < 2-b-c-d > M R < c > X < d > O < 4-e > Z < e >, bulk phase doping elements of the matrix are M and Z, a crystal face induction element is X, and a modification doping element is R; the coating layer is a compound comprising a coating element M '; a supported crystal face inducer is also adopted for further inhibiting the growth of the crystal face (111) and reducing the area of the crystal face (111) so as to form the positive electrode material of a polyhedral spinel crystal structure comprising at least 26 crystal faces, and the crystal face inducer comprises a phosphorus-containing compound, a boron-containing compound or at least + 5 valence metal salt; the Mn dissolution reaction is reduced, and the electrochemical performance of the lithium manganate is improved.

The invention relates to the field of material preparation, and discloses a preparation method and system for realizing a silylene heating material, and the method comprises the following steps: firstly, obtaining a high-purity silicon raw material, analyzing purity factors, screening basic raw materials, measuring key components, then constructing a synthesis process route according to the components, proportioning reaction aids to optimize active parameters, and finally preparing a silylene heating material. The method comprises the following steps: preparing a silylene initial product by using chemical vapor deposition equipment, analyzing a crystal structure, evaluating lattice quality based on structural data, formulating a post-treatment process to remove impurities, detecting a heating performance index to calculate heating efficiency, constructing a material heating framework, querying a heat conduction factor to generate a preparation process flow, and finally establishing a quality control system according to the process flow. And querying heat fluctuation mining data, and generating a preparation management strategy. The material preparation efficiency of the silylene heating material can be improved.

The invention provides a Si-based InGaAs photoelectric detector and a preparation method thereof. The Si-based InGaAs photoelectric detector comprises a Ge transition layer, a GaAs transition layer and a non-doped InP buffer layer, wherein the Ge transition layer, the GaAs transition layer and the non-doped InP buffer layer sequentially grow on the surface of a silicon substrate; the lower doped InP layer, the non-doped InGaAs absorption layer and the upper doped InP layer are sequentially grown on the surface of the non-doped InP buffer layer. The Si-based Ge epitaxial layer, the Ge-based GaAs epitaxial layer and the GaAs-based InP epitaxial layer which are mature in process are sequentially inserted between the Si substrate and the III-V group heteroepitaxial thin film, the crystal structure type difference of direct epitaxial growth of InGaAs on Si is eliminated, the lattice constant mismatch degree is reduced, the defects of the InGaAs epitaxial layer are reduced, the quality is improved, and a high-performance detector is better prepared.

The invention relates to a positive electrode material containing an O2-phase single crystal lithium-rich material, a pole piece, a preparation method and application. The positive electrode material containing the O2-phase single crystal lithium-rich material is a mixed composite material of an O2-phase single crystal lithium-rich positive electrode material and an O3-phase polycrystal lithium-rich positive electrode material, and in the positive electrode material containing the O2-phase single crystal lithium-rich material, the O2-phase single crystal lithium-rich positive electrode material and the O3-phase polycrystal lithium-rich positive electrode material keep respective crystal structure independence; the mass ratio of the O2-phase single crystal lithium-rich positive electrode material to the O3-phase polycrystal lithium-rich positive electrode material is (1: 1)-(1: 10); the O2-phase single-crystal lithium-rich positive electrode material is of a micron-grade pure-phase structure, the particle size is 1-5 microns, the chemical structural formula is LimLi < x > < 1 > Ni < y > < 1 > Co < z > < 1 > Mn < 1-x-y-z > < 1 > O2, m ranges from 0.72 to 0.75, x1 ranges from 0.17 to 0.22, y1 ranges from 0.04 to 0.08, and z1 ranges from 0 to 0.05; the particle size of the O3-phase polycrystalline lithium-rich positive electrode material is 8-10 [mu] m, the chemical structural formula of the O3-phase polycrystalline lithium-rich positive electrode material is Li < x > < 2 > Ni < y > < 2 > Co < z > < 2 > Mn < 1-x-y-z > < 2 > O < 2 >, the range of x < 2 > is 1-1.2, the range of y < 2 > is 0.13-0.4, and the range of z < 2 > is 0-0.13.

The invention relates to the technical field of material testing, and discloses a phase change temperature calibration method and system for a phase change material, and the method comprises the steps: collecting the surface temperature distribution data and crystal structure parameters of the phase change material based on a bimodal synchronous monitor, and building a temperature-structure incidence matrix; when the parameters of the crystal structure suddenly change, determining surface temperature distribution data corresponding to a sudden change moment based on the temperature-structure incidence matrix, and calculating an initial phase change temperature interval; constructing a nonlinear mapping model of the initial phase-change temperature interval and the heating rate, and performing dynamic compensation on the initial phase-change temperature interval based on the nonlinear mapping model to obtain a corrected phase-change temperature; inputting the corrected phase change temperature into a gradient temperature control module containing a standard sample; and comparing the offset of the actual phase change position and the theoretical position of the reference material, and reversely correcting and correcting the phase change temperature based on the offset to obtain the final calibration temperature. The calibration accuracy of the phase change temperature of the phase change material can be improved.

The invention relates to the technical field of heat-conducting materials, in particular to a heat-conducting silica gel sheet and a preparation process thereof, and the heat-conducting silica gel sheet is prepared from the following components in parts by weight: 100 parts of organic silicon rubber; 300-500 parts of a heat conducting filler; 3-8 parts of a curing agent; 1-3 parts of a catalyst; according to the invention, a composite system of silicon carbide particles with a specific crystal structure, surface-modified graphene sheets and nano-diamond particles is used as a heat-conducting filler, and the filler is subjected to accurate proportioning and surface treatment, so that not only is the heat-conducting efficiency greatly improved, but also the internal binding force and heat stability of the material are effectively enhanced; compared with a traditional heat-conducting silica gel sheet, the heat-conducting silica gel sheet can more effectively transfer heat and reduce thermal resistance under the same condition, so that the heat dissipation performance and operation reliability of electronic equipment are improved, and in addition, the heat-conducting silica gel sheet has good mechanical performance and machinability and is easy to adapt to various complex application scenes.

The invention relates to a nonlinear optical crystal structure, a preparation method thereof and optical equipment. The nonlinear optical crystal structure comprises a plurality of material layers which are stacked in the direction perpendicular to the two-dimensional plane of the material layers. Each material layer is of a crystal structure with y-weight rotational symmetry and has a predetermined crystal lattice direction in a direction parallel to a two-dimensional plane; a non-zero deflection angle is formed between the adjacent material layers, and the deflection angle is an included angle of the preset crystal lattice directions of the adjacent material layers; wherein y is 1, 2, 3, 4 or 6. According to the nonlinear optical crystal structure and the preparation method thereof, the rotational symmetry crystals are stacked, and nonlinear enhancement of second harmonics and even higher harmonics is achieved by controlling the deflection angle between the material layers. Compared with a traditional nonlinear metasurface scheme, the nonlinear optical crystal structure can achieve higher accuracy, higher operability and higher efficiency.

The present invention relates to a niobium metal oxide, niobium metal oxide secondary particles and a method for preparing the same, and a working electrode and an electrochemical cell comprising the niobium metal oxide secondary particles. The niobium metal oxide has the formula (I): NbxMyOz, where M is a metal selected from the group consisting of Ti, Zr, V, Cr, W and Mo, x is 2 to 18, z is 2.5 x + 3y and x / y is 1 to 3, and the crystal structure of the niobium metal oxide is a tetragonal tungsten bronze structure having four or eight pentagonal channels per cell, and a portion of the pentagonal channels is filled with-Nb-O-Nb-O-chains, and the remainder of the pentagonal channel is optionally embedded with lithium.