9 results about "Coordination number" patented technology

The invention discloses a theoretical calculation method for solid formation enthalpy of an energetic material. The theoretical calculation method comprises the following steps: calculating enthalpy of the energetic material; calculating enthalpy of reference molecules with different coordination numbers of each element in the energetic material; according to the enthalpy of the reference molecule, calculating the equivalent enthalpy value of each element in the energetic material at different coordination numbers; and calculating the solid formation enthalpy of the energetic material. The theoretical calculation method has the characteristics of simplicity and high precision, does not depend on any empirical parameter, does not need a high-precision density functional group, does not need fitting or machine learning, does not need experimental measurement data, can directly calculate the solid formation enthalpy of any CHON structure, and is very easy to expand to other elements and systems.

The present application belongs to the field of chemical thermodynamics, and particularly relates to a thermodynamic model for predicting the thermodynamic properties of a salt-solvent system. The model first obtains the coordination number n of cations and anions in the salt-solvent system through molecular dynamics simulation, then obtains the initial configuration of the cation-n solvent molecule-anion through configuration optimization, and obtains the most stable structure through quantum chemistry calculation program optimization, and finally obtains the VLE (vapor-liquid equilibrium) data prediction value of the salt-solvent system based on the COSMO-RS theory. The model can obtain the prediction value with high accuracy without experiment, thereby saving a large amount of manpower, material resources and financial resources. Meanwhile, the present application also discloses the phenomenon that the salt in the salt-solvent system is volatile.

The invention relates to the technical field of analytical chemistry and hydrometallurgy, in particular to a method for measuring coordination number of organic acid and RE < 3 + > by using a molar ratio method. The method comprises the following steps: S1, preparing a plurality of organic acid solutions of CY with different concentrations, preparing a RE3 + solution of CM, mixing the organic acid solutions and the RE3 + solution in an isovolumetric manner, adjusting the pH value, and carrying out a complexation reaction; s2, carrying out ultraviolet spectrophotometric measurement, determining the maximum absorption wavelength, and determining the absorbance A of the solutions after the complexation reaction under the maximum absorption wavelength; s3, drawing by taking the molar ratio n = [CY] / [CM] as a horizontal coordinate and the absorbance A as a vertical coordinate, and finding out an interval in which the absorbance linearly rises along with the increase of n and an interval in which the absorbance reaches a platform or the slope is obviously changed; linear fitting is conducted on the data points of the two intervals, two straight lines are obtained, and the value of an abscissa n corresponding to the intersection point of the two straight lines is the coordination ratio of the complex. The method is reliable in result, low in cost, easy to popularize, convenient and fast.

The invention relates to the technical field of material science, in particular to a full-coordination covalent organic framework material as well as preparation and application thereof. The full-coordination covalent organic framework material provided by the invention has a double-layer close packing structure with a main hole of 9.5 angstroms, a narrow hole of 3.0 angstroms and an interlayer spacing of 4.1 angstroms; the nitrogen content is 51.85%, and the phosphorus content is 26.50%. Nitrogen and phosphorus elements serve as multiple coordination sites and are directly coordinated with lanthanide ions, the close packing structure amplifies the influence of the ion radius and the coordination number on the coordination effect, the adsorption capacity of europium (Eu < 3 + >) of 334 mg / g is achieved, and the separation factor of the europium (Eu < 3 + >) to cesium (Cs < + >) and strontium (Sr < 2 + >) reaches up to 7153 and 9660. The full-coordination covalent organic framework material structure is proved to have good selectivity on the lanthanide elements, and high-capacity adsorption and enrichment of the lanthanide elements can be realized.

The invention discloses a method for characterizing water distribution uniformity of a porous material in water and application, and belongs to the technical field of porous material performance characterization. The method comprises the following steps: 1) constructing a porous material simulation system, inserting water molecules, and starting an NVT ensemble to carry out pre-balancing and finished product simulation; 2) calculating a coordination number function N1 (r) of oxygen atoms of water molecules based on the finished product simulation trajectory, and obtaining a first water molecule density rho1 (r) within a radius r range by combining the sphere volume; (3) subtracting N1 (r) and the sphere volume from the total water molecule number and the total volume of the system respectively, and calculating the second water molecule density rho2 (r) outside the range of r; and 4) calculating the density ratio R (r) = rho1 (r) / rho2 (r), and judging the uniformity according to the mean value of the R (r) within the range from 0.3 nm to half of the minimum side length of the box. The method realizes quantitative evaluation of water distribution uniformity, has the advantages of convenient operation, high quantification precision, wide applicability and reliable data, can be applied to performance evaluation of porous materials such as UiO-67 and graphene, and provides theoretical support for material design optimization in the fields of drying, atmospheric water collection and the like.

The invention discloses a two-dimensional material, which is characterized in that the molecule of the material is a double-element three-layer sandwich planar macromolecule with an (AMA) N structure formed by combining any transition element atom M containing an unfilled d track or f track in the periodic table of elements and a main group active metal element atom A, the coordination number of atoms of the M atomic layer is saturated coordination 12, the coordination number of the M atoms is smaller than or equal to 12 at the edge of a molecular plane, and subscript N is a natural number larger than or equal to 4 and represents the number of atoms of the same kind in each layer of macromolecules. According to the invention, the practical problems of small size, high manufacturing cost, difficulty in industrial production technology development and the like of the current two-dimensional material are solved by the rotational symmetry of intramolecular atom saturated coordination bonds, the extension ductility of endogenous electron cloud flat bands and the ductility of the macroscopic two-dimensional material formed by splicing and laminating.

The invention discloses a method for regulating the coordination environment of a single atom and nitrogen; the invention aims to provide a method for regulating the coordination environment of a single atom and nitrogen, and opens up a path for rationally designing a catalyst with high activity, high selectivity and high stability for use in certain demanding reactions; the technical scheme comprises the following steps: 1) adding different ligands to change the coordination regulation of the metal active center during the preparation process of dispersing and loading or encapsulating the metal active center on a carrier material at the atomic level, such as using ball milling, atomization and impregnation methods to achieve atomic-level dispersion of the metal active center; 2) changing the coordination number of the metal active center by adjusting the calcination temperature, calcination time, calcination atmosphere and calcination times; the invention belongs to the field of materials science and engineering technology.

This invention relates to a method for predicting the occupancy of alloying elements in metallic nanopores, belonging to the field of metallic material defect prediction technology. The method includes the following steps: Simulated annealing to obtain a stable structure: obtaining the most stable structure of nanopores of different sizes through a simulated annealing model of stable metallic pore structures; Coordination number analysis and screening: analyzing the coordination distribution of the inner walls of the nanopores and classifying and screening the inner wall atoms according to the coordination number; DFT energy calculation and induction: using VASP software based on the DFT method to calculate the energy property parameters of candidate lattice points after being occupied by alloying elements, and summarizing the correlation between the energy property parameters and the coordination distribution information. This invention avoids the shortcomings of high-symmetry point selection methods and manual random selection methods, while significantly reducing the computational load of all calculation methods, exhibiting significant advantages in both efficiency and reliability.

The invention discloses a phase structure identification method of a fluorite structure polycrystal multiphase body, and mainly solves the problems of incomplete phase identification and unclear component statistics of a fluorite structure ferroelectric body in the prior art. According to the scheme, the method comprises the following steps: 1) based on an atomic structure of a standard fluorite structure ferroelectric, modeling unit cell structures of an M phase, a T phase, a C phase and a PO phase; 2) summarizing an atomic structure descriptor, and determining a phase structure judgment standard based on the descriptor; 3) on the basis of neighbor atom identification, determining a neighbor atom identification radius through a radial distribution function of a multiphase structure, and respectively calculating coordination number, bond length and bond angle; the method comprises the following steps of (1) carrying out primary division on atoms through atomic coordination numbers, distinguishing a T phase and a C phase based on bond length, distinguishing an M phase and a PO phase based on bond angle, and introducing an unknown structure for characterization, and (5) completing quantitative statistics and visualization of a local region, and can obviously improve the recognition accuracy of various phase structures, and realize phase structure statistics and visualization analysis.