An object of the present invention is to provide a novel method for determining the structure of a target substance contained in a multicomponent sample. The present invention provides a method of determining the structure of a target substance contained in a mixture of two or more substances, wherein the method includes the steps of: isolating the target substance from the mixture by means of supercritical fluid chromatography, soaking the isolated target substance into a crystalline sponge to produce a sample for crystallography, and performing a crystallographic analysis on the sample for crystallography. A volatile solvent can be used as a mobile phase in the supercritical fluid chromatography.

An object of the present invention is to provide a novel method for determining the structure of a target substance contained in a multicomponent sample. The present invention provides a method of determining the structure of a target substance contained in a mixture of two or more substances, wherein the method includes the steps of: isolating the target substance from the mixture by means of supercritical fluid chromatography, soaking the isolated target substance into a crystalline sponge to produce a sample for crystallography, and performing a crystallographic analysis on the sample for crystallography. A volatile solvent can be used as a mobile phase in the supercritical fluid chromatography.

Methods for determining a weathering index using x-ray diffraction (XRD) data are provided. An exemplary method includes obtaining XRD data of a weathered rock sample, and calculating the weathering index using a formula developed to use the XRD data.

Methods for determining a weathering index using x-ray diffraction (XRD) data are provided. An exemplary method includes obtaining XRD data of a weathered rock sample, and calculating the weathering index using a formula developed to use the XRD data.

A stable Crystalline Form II of non-solvate of Apremilast (Formula I), methods of making Form II, pharmaceutical compositions comprising Form II, and their uses are disclosed. Also discloses are mixed crystals comprising Form Hand Form B and methods of making the same. The crystalline forms are characterized using X-ray powder diffractometry (XRPD), infrared spectroscopy (IR), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TG). As compared with Forms A, B, C, D, E, F, and G reported in prior art references, Apremilast Form II of the present invention is more stable to temperature, light, and humidity, and is more suitable for long term storage; the crystallization solvents are safe and can be easily removed; the Form II has a white or off white appearance, and can be directly used in preparation processing; the preparation methods are simple and easy to reproduce, and are suitable for industrialized production.

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The present invention provides a method to calculate refinement parameters from an observed diffraction pattern for powder samples accurately. A method to calculate a best solution of the crystal structural parameters from a diffraction pattern, comprising: a third calculating step of the converged values 600 to calculate at least three converged values; a third judging step of the best converged values 700 to calculate at least three criteria from the peak-shift parameters in the converged values and to judge whether the converged values are a true solution of not by using the criteria; and a first calculating step of a global solution 800 to calculate a global solution of which is the true value by using the criteria.

The present invention provides a method to calculate refinement parameters from an observed diffraction pattern for powder samples accurately. A method to calculate a best solution of the crystal structural parameters from a diffraction pattern, comprising: a third calculating step of the converged values 600 to calculate at least three converged values; a third judging step of the best converged values 700 to calculate at least three criteria from the peak-shift parameters in the converged values and to judge whether the converged values are a true solution of not by using the criteria; and a first calculating step of a global solution 800 to calculate a global solution of which is the true value by using the criteria.

Disclosed, is a sample preparation apparatus which is configured to prepare a material sample suitable for X-ray diffraction. The apparatus comprises a dished sample holder bottom configured to fit within an annular sample holder. The dished sample holder bottom has a concave dished surface which is adapted to distribute sample material under pressing forces. A method of preparing a material sample suitable for X-ray diffraction is also disclosed. The method comprises dosing a dished sample holder bottom which is configured to fit within an annular sample holder with sample material, wherein the dished sample holder bottom preferably has a concave dished surface which is adapted to distribute sample material under pressing forces.

The present disclosure provides a method for determining free radicals of CaO—Al.sub.2O.sub.3 series oxide melts. The method includes dividing the CaO—Al.sub.2O.sub.3 series oxide powder to into two aliquots by mass, putting into two identical corundum crucibles and tamping. The method also includes heating the two aliquots at the same high temperature in furnaces with and without a static magnetic field, respectively. Cylindrical samples with the same diameter and height, and only containing the melt at the bottom of the crucible and the slag reaction interface are drilled out from said two crucibles and ground into powder samples. The free radical relative content of the CaO—Al.sub.2O.sub.3 series oxide melts can be calculated from a ratio between the difference of the reaction mass contents of CaO in the two powder samples and the total mass content of CaO.

Methods for determining mineral compositions of materials are described. The methods include obtaining elemental data associated with a geologic sample, calculating a measurement correlation matrix of the geologic sample from the elemental data, calculating an artificial correlation matrix, comparing the measurement correlation matrix and the artificial correlation matrix to determine an error value, minimizing the error value by updating the artificial correlation matrix and comparing the measurement correlation matrix to the updated artificial correlation matrix, and determining a mineral composition of the geologic sample based on the minimized measurement correlation matrix.