89 results about "Quantum chemistry" patented technology

The invention belongs to the technical field of quantum chemistry, and particularly relates to a molecular structure and chemical reaction energy function building method based on a neural network. The method comprises the steps of performing sampling on each degree of freedom of a molecular or chemical reaction; searching for a low-energy conformation structure through quantitative calculation; performing energy calculation on the structure, and preparing a training set and a test set; selecting a proper coordinate representation structure; according to different coordinates, constructing different features to describe the structure; selecting a proper neural network; selecting a proper method to train the neural network; after the training is completed, performing error statistics on thetest set, and when an error is smaller than 1.0 kcal/mol, ending the training; and if the error is greater than 1.0 kcal/mol, following a re-searching model. The precision of obtained conformation energy, reaction energy and the like is higher; the method can be widely applied to the quantum dynamics and molecular dynamics processes; and not only a single molecule conformation but also the chemical reaction including intramolecular or intermolecular bond breaking and generating can be simulated.

The invention discloses a method for forecasting the acute toxicity of organic compounds by building a quantitative structure-activity relationship model with a quantum chemistry method. The method fully geometrically optimizes compound structures by using a Gaussian procedure so as to obtain quantum chemistry parameters including molecular volume, relative molecular mass, highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy, energy gaps of frontier molecular orbital, dipole moment, solvation energy, electron energy and the like; using the quantum chemistry parameters and a hydrophobicity parameter as structural descriptors; in combination with toxicity data, quantitative relationship equations between various structural descriptors and toxicity are established according to a written procedure based on partial least square stepwise linear regression to obtain the multiple correlation coefficient, F-test value and sum of squared residuals, and then the model is verified so as to guarantee the external predictive ability. Therefore, the method can quickly and effectively forecast the toxicity of organic compounds to be studied, and provide necessary basic data for risk assessment and supervision of chemicals.

Embodiments of the present invention provide, among other things, methods, apparatus, and systems for tuning a semiempirical process for predicting energy for different molecular configurations. In an example method, an energy value and an energy gradient are determined for each of a plurality of molecular configurations using an accurate method. A functional form of the semiempirical process is optimized using the determined energy values and energy gradients via multiobjective optimization. The functional form relates one or more parameters to energy values and energy gradients.

The invention provides a molecular property prediction method and system, and relates to the fields of quantum chemistry/computational chemistry, chemical informatics and machine learning/artificial intelligence. Under the framework of chemical multi-world explanation, a density functional theory, chemical informatics and machine learning/artificial intelligence means are used, information such asa molecular structure, a base group, a functional and the like is used as input, and a prediction result of molecular property is output through a machine learning model. According to the method, anytype of molecular structure and any calculation strategy can be predicted, and the method is more accurate than a common experience method and a regression analysis method.

The invention provides a quantum chemistry reaction optimization multi-relay selection method of a cognitive relay network. The method comprises steps of: 1, establishing a cognitive system relay selection model; 2, initializing a quantum molecule set and a system parameter; 3, evaluating the potential energy of all quantum molecules in the set and selecting the measurement state of the quantum molecule with the lowest potential energy as a global optimal solution; 4, arranging the kinetic energy of quantum molecules in a descending order, and performing decomposition reaction, invalid collision, and synthetic reaction; 5, evaluating the potential energy of newly generated quantum molecules, and if the minimum potential energy of the newly generated quantum molecules is less than the minimum potential energy of the previous generation, marking the newly generated quantum molecules as a new global optimal solution; and 6, if the number of iteration times is less than a preset maximum number of iteration times, returning to step 4, otherwise, outputting the global optimal solution. The method balances the primary user constraint condition and non-primary user constraint condition of the cognitive relay network, and chooses a relay selection scheme that maximizes the system throughput based on a quantum chemistry reaction mechanism.

The invention discloses a method for adopting a quantitative structure-activity relation model to predict a reaction rate constant of chlorine free radical of organic chemicals. According to the method, a quantum chemistry descriptor with structural characters is figured out only by means of basic molecular structure information of the organic chemicals, and by adopting a constructed QSAR prediction model, a kCl value of the organic chemicals can be predicted quickly and efficiently. The method follows a guide rule issued for the construction and verification of a QSAR model by the Organization For Economic Co-Operation And Development (OECD). According to the method, by adopting a genetic algorithm-multiple linear stepwise regression analysis combination use method (GA-MLR) and a supportvector machine-multiple linear stepwise regression analysis combination use method (SVM-MLR), the transparency degree is high and more convenience is provided for application; since quantum chemistrydescriptors are adopted in all GA-MLR models, the physical meaning of the descriptors is clear; the method has a specific application domain, and is applicable to abundant organic varieties, excellentin goodness of fit, robustness and prediction capability, easy to program and capable of supplying important data support to environmental risk evaluation and management of the organic chemicals.

A luminescent material includes transition metal complex comprising a ligand in which an electron density of a p orbital of a highest occupied molecular orbital level is higher than 0.239 and lower than 0.711 when the electron density is calculated according to quantum chemical calculation (Gaussian09/DFT/RB3LYP/6-31G), the p orbital being in the outermost shell of an element coordinated to the metal.

The invention discloses a method for designing flotation reagent molecules based on fragments. With the help of a computer auxiliary molecule design technique, molecular mechanics and quantum chemistry calculation, the active fragments which are small in molecular weight and high in relative combination efficiency are obtained by sieving through detection, then flotation reagent molecular structures high in activity are obtained after the methods of producing, splicing and fusing are utilized for optimizing the active fragments, and the flotation reagent molecules are obtained through the steps that a fragment molecular compound library is established, active fragment molecules are sieved, and lead compounds are sieved. The dual advantages of high efficiency of the computer auxiliary molecule design technique and the flexibility of a molecule assembly technology are combined; the inspection range for the molecules is scaled to the inspection range for the molecular fragments, in this way, the success rate of reagent formulation is greatly increased for the reagent molecules, the designing efficiency is effectively promoted for the flotation reagent molecules, and the new method isfurther provided for designing flotation reagent.

The invention relates to a method of for evaluating the collecting performance of a floatation collecting agent to andalusite. The technical scheme is: firstly establishing an andalusite crystal structural model and a floatation collecting agent molecular structural model, so that total energy ET (andalusite) and ET (collecting agent) of the andalusite crystal structural model and the floatation collecting agent molecular structural model can be obtained by adopting a specific Hareree-Fock-Roothaan method of quantum chemistry Ab initio method; then carrying out molecule geometry optimization calculation on the structural models of an andalusite-floatation collecting agent system, thus the total energy ET (andalusite-collecting agent) of the andalusite-floatation collecting agent system isobtained; and finally acquiring the emitted heat amount delta ET when the floatation collecting agent is absorbed on the andalusite, if the absolute value of the delta ET is greater, the collecting capability of the floatation collecting agent to the andalusite is high. According to the size of the bond order of the andalusite-floatation collecting agent, the property and instensity of the bond formed by the surface of the andalusite and the floatation collecting agent are evalued. The method provided by the invention is simple and reasonable, is easy to operate, has low cost, and has practical value.

The invention relates to a method for constructing a complex organic macromolecular average molecular structure model and belongs to a method for constructing an organic macromolecular structure model. The method for constructing the complex organic macromolecular average molecular structure model by adopting an in-situ process comprises the following steps: (1) analyzing elements; (2) analyzing peak slit of an infrared spectrum; (3) performing thermal gas chromatography and mass spectrometry analysis; and (4) performing quantum chemistry calculation. According to the method, the construction for the complex organic macromolecular average molecular structure model, such as, coal, can be realized. The invention has the advantages that an in-situ structure presentation method is utilized to acquire the parameters and segments of a complex macromolecular structure; a comprehensive theoretical calculation method is adopted for constructing a complex macromolecular structure model; the infrared spectrum information acquired through theoretical calculation is compared with experimental spectrum information and the macromolecular structure model is constantly corrected, so that the constructed macromolecular structure is more objective and can reflect the true structure information of the macromolecular structure model; and the research on the property, utilization and conversion of the complex macromolecular material, such as, coal, can be benefited.

The invention discloses a method for testing activity of a methanol fuel cell anode material. The method is characterized in that the activity of the cell anode material is tested through special quantum chemistry calculation simulation for improving the accuracy of judging the activity and the efficiency of a cell. The method comprises the following steps: firstly, analyzing an adsorption structure, thermodynamics and kinetics parameters of an elementary reaction, and the like by researching the adsorption of the methanol on the surface of the anode material and three broken bond reaction principles of methanol; and secondly, performing comparative analysis on an energy barrier obtained by using calculation, a PDOS (Partial Density Of States) graph and an electrochemical potential to judge the activity of a catalyst. The activity of the methanol fuel cell anode material is conveniently, rapidly and accurately researched by using the method; resources are saved.

The invention relates to a construction method and application for a food-borne polypeptide antioxidant activity three-dimensional quantitative structure-activity relationship model. The method comprises the steps of using a food-borne polypeptide with known activity as a research object, utilizing the three-dimensional quantitative structure-activity relationship technology for establishing the food-borne polypeptide antioxidant activity three-dimensional quantitative structure-activity relationship model, and adopting the MM+ method the semi-empirical quantum chemistry method AM1, the DFT method and other quantum chemistry technologies to obtain quantum chemistry parameters. According to the construction method, analysis and statistics are carried out on the food-borne polypeptide quantum chemistry parameters, the antioxidant activity sites of the food-borne polypeptide are determined, and quantitative structure-activity model is constructed by utilizing the bond length, charge distribution, frontier molecular orbit energy parameters of the activity sites and food-borne polypeptide antioxidant activity values. The constructed model can rapidly and accurately predict the activity value of the food-borne polypeptide with the unknown activity, and the relationship between the antioxidant activity and structural features can be reasonably explained; compared with a traditional high throughput screening technology, the screening efficiency is greatly improved, and the cost is reduced.

The invention discloses a calculation method and device for a molecular ionization collision cross-section. On the basis of a DM formula, the calculation level of quantum chemistry is determined, andan optimal method for a specific system is proposed. The method comprises the steps that S1, modeling is performed on a molecular structure, and quantum chemistry calculation is utilized to solve a self-consistent field equation to obtain an optimal structure of molecules; S2, wave function analysis is performed on the optimal structure of the molecules through a Hartree-Fock method, a Mulliken population of the molecules is obtained, and energy of each molecular orbit is determined; S3, weight values of the molecular orbits composed of all valence electrons are acquired; and S4, the ionization collision cross-section of the molecules is obtained through calculation by use of a preset first formula and a preset second formula.

A synthetic route evaluation system extracts an optimal synthetic route from a plurality of synthetic routes for a target compound to be synthetically produced. The synthetic route evaluation system includes an arithmetic processing device, which is composed of a quantum chemistry calculation unit, a reaction mechanism analysis unit, and a synthetic route ranking unit, and a storage device for storing data relative to the synthetic routes.

The invention discloses an evaluation method for simulating oil-water interface characteristics of an alkylbenzene sulfonate surfactant based on molecular dynamics. The method comprises establishing amolecular structure model of alkylbenzene sulfonate by adopting software; then, performing quantum chemistry calculation by utilizing software to obtain optimized molecular conformation and all-atomic structure charge parameters of alkylbenzene sulfonate; optimizing the molecular structure of alkylbenzene sulfonate to obtain optimized molecular topological structure parameters of the bond length,the bond angle and the dihedral angle; establishing a system model of oil-phase molecules, water molecules and alkylbenzene sulfonate by utilizing molecular accumulation software; and finally carrying out molecular dynamics calculation on a simulation system by utilizing molecular dynamics calculation software to evaluate the oil-water interface characteristics of alkylbenzene sulfonate. According to the method, the oil-water interface microcosmic action mechanism of the alkylbenzene sulfonate surfactant for chemical flooding can be clarified from molecular and atomic scales, and certain theoretical guidance is provided for application of alkylbenzene sulfonate in the field of oilfield chemical flooding.

A Fe-C-Cr-W-Mo-Mn-V-Si-Ni high carbon medium-alloy steel relates to an alloy steel. The alloy steel is determinated according to matrix martensite cell binding energy calculation, yield strength prediction, quenching and tempering hardness calculation, toughness estimation and non-carbide forming elements alloy components by the use of quantum chemistry procedure combined with interatomic potentials. The alloy steel contains the following components of: by weight, 93.08% of Fe, 0.56% of C, 1.42% of Cr, 2.21% of W, 0.95% of Mo, 0.34% of Mn, 0.53% of V, 0.62% of Si and 0.29% of Ni. The alloy steel can be quenched at a low temperature, has carbides with fine microstructure distribution, simultaneously has high hardness and toughness, and is a high carbon medium-alloy tool and die steel which can satisfy the demand of using performance.

The invention belongs to the crossing field of energetic material and quantum chemistry and particularly relates to a bis(tetrazole-2-oxy-4-hydro)amine, a design method, and an application thereof. 1-hydro-tetrazole-3-oxy is employed as a mother compound and two 1-hydro-tetrazole-3-oxy compounds are combined through connection of an NH bridge group, and then through structure optimization, a planar conjugated molecule is formed; through energy containing property calculation, thermostability calculation and sensitivity calculation, comprehensive performance of the product is evaluated. The bis(tetrazole-2-oxy-4-hydro)amine has high energy and low sensitivity and can be used as a substitute of hexogen and octogen.

The invention discloses a method for calculating the crystal morphology of an energetic material in a solution. According to the method, an adsorption site of a solvent on a growth crystal face is found through molecular dynamics simulation, binding energy at the adsorption site is calculated through adoption of a quantum chemistry method, and the binding energy is used for replacing 'averaged' solvent-crystal face interaction energy in an adhesion energy model, so that the inhibition effect of the solvent on solute growth is described more reasonably. Compared with the prediction result of the original adhesion energy model, the crystal morphology predicted based on the method is greatly improved, and is well matched with experimental data. The method provides an early-stage theoretical prediction and scientific basis for crystallization morphology control of energetic materials.

Quantum computations based on second quantization are performed by applying one body and two body terms in a selected order. Typically, terms associated with operators that commute are applied prior to application of other terms. In a particular example, one body terms of the form h pp are applied first, followed by two body terms of the form h prrp .

Disclosed herein are a method for quantitatively analyzing a molecular orbital distribution, and a quantitative analysis system of molecular orbital distributions using the same. The method comprise a) selecting two molecular orbitals to be compared for molecular orbital distributions and computing molecular orbital distributions by quantum chemistry calculation; b) calculating structural properties of each molecular orbital by means of an RDM (radially discrete mesh) calculation method, followed by matching with the molecular orbital distributions computed in step a) to obtain molecular orbital distributions according to the structural properties; and c) comparing the two molecular orbital distributions according to structural properties, obtained by RDM in step b), using a profiling method.

The invention discloses a 3,6,7-triamino-1,2,4-triazolocycle ionic type nitroazole compound and a preparation method thereof. The preparation method of the 3,6,7-triamino-1,2,4-triazolocycle ionic type nitroazole compound comprises the following steps: dispersing a 3,6,7-triamino-1,2,4-triazolocycle compound and a nitroazole type-1H compound in right amount of deionized water, heating, reacting, then standing, filtering out a solid after temperature is reduced to normal temperature, washing the solid, and drying, so that the 3,6,7-triamino-1,2,4-triazolocycle ionic type nitroazole compound is obtained, wherein the nitroazole type-1H compound is one of 2,4-dinitroimidazole-1H, 4,5-dinitroimidazole-1H, 3,5-dinitroparazole-1H, 3-amino-5-nitro-1,2,4-triazole-1H, 3-nitro-1,2,4-triazole-5-one and 5,5'-dinitro-3,3'-bi-triazole-1H,1'H. The preparation method of the 3,6,7-triamino-1,2,4-triazolocycle ionic type nitroazole compound is simple, no toxic substance or byproduct is produced, conditions are mild, yield is high, and detonation velocity, through quantum chemistry calculation, of the obtained product is 8500-9200m/s.

The invention discloses a method for quantitatively analyzing hydrogen evolution activity of an MCNT catalyst. The method quantitatively analyzes the hydrogen evolution activity of the MCNT catalyst on the basis of quantum chemistry density functional theory simulation. Through stability study of an MCNT model, stable existence of the model in a hydrogen evolution reaction process is determined; the specific position of a hydrogen evolution reaction on the surface of the catalyst is determined according to adsorption potential screening; the hydrogen evolution activity of the MCNT catalyst isquantitatively analyzed in combination with calculation of hydrogen adsorption free energy and a hydrogen evolution reaction route. The method comprises steps including construction of an MCNT catalyst model, optimization of the model structure, stability calculation, adsorption potential screening, calculation of hydrogen adsorption free energy and the hydrogen evolution reaction route as well asanalysis and representation of the hydrogen evolution activity. The hydrogen evolution activity of the MCNT catalyst can be quantitatively analyzed without actual experiments and actual synthesis ofthe catalyst.

The invention discloses a simulation method for optimizing molecular structure of biosurfactant. Through a specific quantum chemistry geometry optimization method, the molecular structure of the biosurfactant is optimized for making the stable configuration of a biosurfactant molecule in molecular dynamics simulation clear. The method comprises the following steps: firstly, through Materials Studio software, constructing an initial configuration of the biosurfactant molecule; secondly, utilizing Calculation in the DMol3Tools module of the Materials Studio software to carry out a molecular structure optimization process on the biosurfactant; and finally, through vibration frequency obtained by calculation, judging the stable configuration of the biosurfactant. The simulation method provides a stable and accurate molecular model for the molecular dynamics simulation of biosurfactant property, and guarantees the accuracy and the reliability of simulation.

A method for predicting activity of an angiotensin converting enzyme inhibitor comprises the steps of selecting quantum chemistry parameters of natural amino acids, obtaining 19 principal components by principal component analysis, enabling the principal components to serve as principal component amino acid quantization parameters for describing every amino acid, utilizing amino acid quantum chemistry parameter scores to perform representation on an amino acid sequence of the angiotensin converting enzyme inhibitor, enabling medicine activity of the angiotensin converting enzyme inhibitor to serve as to a dependent variable for establishing a model, utilizing a step-by-step linear regression method to perform variable selection, finding out amino acid quantum chemistry parameter components remarkably associated with the dependent variable, utilizing step-by-step linear regression to process all the quantum chemistry parameter components of the amino acids obtained in every step, sequentially utilizing a method of partial least squares to construct medicine activity models of the angiotensin converting enzyme inhibitor according to an importance sequence of all the quantum chemistry parameter components, and adopting a leave-one-out method to perform cross check and external validation on predicating capability of the evaluation models. The method for predicting the activity of the angiotensin converting enzyme inhibitor has the advantages of being simple to operate and uniform in form and enabling data to be obtained easily and the like.

The invention discloses a global search method based on genetic algorithm, which takes small molecular complexes as objects, and aims to find the structure with the lowest energy and consistent with experimental facts. Including the following steps: building a complex model, chromosome coding; initialization, generating the possible structure of the complex; local optimization using quantum chemical methods; genetic operations, including replication, hybridization, mutation, etc.; repeating the above two steps until the number of iterations is reached ; Read the result and analyze it. This method limits the generation of new structures, and selects a more reasonable method during genetic manipulation, so it can search a wider range in a shorter time and find the correct structure of the corresponding small molecule complexes more effectively.

The invention discloses an absolute configuration identification method for metconazole diastereomer. The method includes the following steps: in the inertia matrix, performing the compressed tablet film-preparing on the metconazole diastereomer to be measured, performing the test on a vibration circular spectrometer (VCD) under the condition of instrument resolution 4 cm<-1> and modulator optimization wave number 1400 cm<-1>, and obtaining the vibration circular spectrum (VCD experiment spectrum) of the metconazole diastereomer; then using quantum chemistry calculation software Gauss View 5.0and Gaussian 09W, after the method is set, respectively regarding four metconazole isomers as a molecule model, and calculating to obtain the VCD theory spectrum; comparing and analyzing the VCD experiment spectrum of the metconazole diastereomer and the signal, frequency and relative strength of the main VCD belt of the theory spectrum, and identifying the absolute configuration of the metconazole diastereomer. The four absolute configurations of the metconazole diastereomer are identified by firstly adopting the VCD spectrum technology, the method is rich in molecular structure information,and is a favorable means used for identifying the absolute configuration of chiral compounds in a high efficiency.