In this paper,Fe-Al solid solution was prepared by mechanical alloying technology,and Fe-Al powder was dispersed into unsaturated polyester (UP) with different contents as absorber to form mixture Fe-Al-UP.The result...In this paper,Fe-Al solid solution was prepared by mechanical alloying technology,and Fe-Al powder was dispersed into unsaturated polyester (UP) with different contents as absorber to form mixture Fe-Al-UP.The results indicate that the alloying process is almost accomplished and most of the particles are nanometer.Meanwhile,the microwave absorbability of Fe-Al-UP samples in frequency from 0.3 MHz to 1.5 GHz was studied.The results indicate that the more the absorber,the better the absorbing property.The absorbing property of Fe-50Al-UP was slightly higher than Fe-28Al-UP.展开更多
Carbonate-bearing fluids widely exist in different geological settings,and play important roles in transporting some elements such as the rare earth elements.They may be trapped as large or small fluid inclusions(with...Carbonate-bearing fluids widely exist in different geological settings,and play important roles in transporting some elements such as the rare earth elements.They may be trapped as large or small fluid inclusions(with the size down to<1μm sometimes),and record critical physical-chemical signals for the formations of their host minerals.Spectroscopic methods like Raman spectroscopy and infrared spectroscopy have been proposed as effective methods to quantify the carbonate concentrations of these fluid inclusions.Although they have some great technical advantages over the conventional microthermometry method,there are still some technical difficulties to overcome before they can be routinely used to solve relevant geological problems.The typical limitations include their interlaboratory difference and poor performance on micro fluid inclusions.This study prepared standard ion-distilled water and K_(2)CO_(3)aqueous solutions at different molarities(from 0.5 to 5.5 mol/L),measured densities,collected Raman and infrared spectra,and explored correlations between the K_(2)CO_(3)molarity and the spectroscopic features at ambient P-T conditions.The result confirms that the Raman O-H stretching mode can be used as an internal standard to determine the carbonate concentrations despite some significant differences among the correlations,established in different laboratories,between the relative Raman intensity of the C-O symmetric stretching mode and that of the O-H stretching mode.It further reveals that the interlaboratory difference can be readily removed by performing one high-quality calibration experiment,provided that later quantifying analyses are conducted using the same Raman spectrometer with the same analytical conditions.Our infrared absorption data were collected from thin fluid films(thickness less than~2μm)formed by pressing the prepared solutions in a Microcompression Cell with two diamond-II plates.The data show that both the O-H stretching mode and the O-H bending mode can be used as internal standards to determine the carbonate concentrations.Since the IR signals of the C-O antisymmetric stretching vibration of the CO32ion,and the O-H stretching and bending vibrations from our thin films are very strong,their relative IR absorbance intensity,if well calibrated,can be used to investigate the micron-sized carbonate-bearing aqueous fluid inclusions.This study establishes the first calibration of this kind,which may have some applications.Additionally,our spectroscopic data suggest that as the K_(2)CO_(3)concentration increases the aqueous solution forms more large water molecule clusters via more intense hydrogen-bonding.This process may significantly alter the physical and chemical behavior of the fluids.展开更多
Near-infrared (NIR) spectroscopy was applied to reagent-free quantitative analysis of polysaccharide of a brand product of proprietary Chinese medicine (PCM) oral solution samples. A novel method, called absorbance up...Near-infrared (NIR) spectroscopy was applied to reagent-free quantitative analysis of polysaccharide of a brand product of proprietary Chinese medicine (PCM) oral solution samples. A novel method, called absorbance upper optimization partial least squares (AUO-PLS), was proposed and successfully applied to the wavelength selection. Based on varied partitioning of the calibration and prediction sample sets, the parameter optimization was performed to achieve stability. On the basis of the AUO-PLS method, the selected upper bound of appropriate absorbance was 1.53 and the corresponding wavebands combination was 400 - 1880 & 2088 - 2346 nm. With the use of random validation samples excluded from the modeling process, the root-mean-square error and correlation coefficient of prediction for polysaccharide were 27.09 mg·L<sup>-</sup><sup>1</sup> and 0.888, respectively. The results indicate that the NIR prediction values are close to those of the measured values. NIR spectroscopy combined with AUO-PLS method provided a promising tool for quantification of the polysaccharide for PCM oral solution and this technique is rapid and simple when compared with conventional methods.展开更多
In this article, we investigate the global behavior of weak solutions of a simplified Ericksen-Leslie system for compressible flows of nematic liquid crystals in time in a bounded three-dimension domain-arbitrary forc...In this article, we investigate the global behavior of weak solutions of a simplified Ericksen-Leslie system for compressible flows of nematic liquid crystals in time in a bounded three-dimension domain-arbitrary forces. By adapting the arguments for the compressible Navier-Stokes equations, and carefully analyzing the direction field of liquid crystals in the equations of angular momentum, we show the existence of bounded absorbing sets, global bounded trajectories, and global attractors to weak solutions of compressible flows of nematic liquid crystals with the adiabatic constant γ〉5/3.展开更多
Boundary procedure is an important phenomenon in numerical simulation. To reduce or eliminate the spurious reflections significantly which is occurred in boundary is a challenging and vital approach. The appropriate a...Boundary procedure is an important phenomenon in numerical simulation. To reduce or eliminate the spurious reflections significantly which is occurred in boundary is a challenging and vital approach. The appropriate artificial numerical boundaries can be applied to eliminate the effect of unnecessary spurious reflections in case of the numerical simulations of wave propagation phenomena problems. Typically, to reduce the artificial reflections, the absorbing boundary conditions are necessary. In this paper, we overview and investigate the appropriate typical absorbing boundary conditions and analyzed the boundary effect of two dimensional wave equation numerically. Reflections over the wide-ranging incident angles are complicated to eliminate, but the absorbing boundary conditions that we have applied are computationally cost efficient, easy to apply and able to reduce reflections significantly. For numerical solution, finite difference method is applied to develop numerical scheme using 2D wave equation. Using the developed numerical scheme, we obtain the numerical solution of the governing equation as an initial boundary value problem and realize the qualitative behavior of the solution in infinite space. The finite difference numerical scheme has been investigated by developing MATLAB programming language code. Numerical results have been discussed and analyzed with presenting different qualitative behavior of the numerical scheme. The accuracy and efficiency of the numerical scheme has been illustrated. The stability analysis was discussed and verified stability condition. Using the numerical scheme and absorbing boundary conditions, the boundary effects and absorption of spurious reflection of boundary have been demonstrated.展开更多
11 oxides (MgO, CaO, BaO, TiO2, V2O5, MnO2, Fe2O3, CuO, ZnO, PbO2 and B2O3), often found in coal-derived carbon materials, were loaded into the coal-derived carbon material by two methods such as adsorbing oxides thro...11 oxides (MgO, CaO, BaO, TiO2, V2O5, MnO2, Fe2O3, CuO, ZnO, PbO2 and B2O3), often found in coal-derived carbon materials, were loaded into the coal-derived carbon material by two methods such as adsorbing oxides through solution onto the surface of coke and adding oxides into the coal before carbonization. The effects of oxides on carbon solution reaction of carbon material were investigated and compared. The results show that the effect trends are similar but the effect of oxides by adsorbing is remarkably greater than that of the oxides by adding oxides as BaO, MgO, Fe2O3, CuO, ZnO, MnO2, PbO2 and B2O3. And the effect trends are similar. BaO, CaO and Fe2O3 are the greatest affecting oxides. The saturation point of addition content is 3% and that of adsorption is 1%.展开更多
文摘In this paper,Fe-Al solid solution was prepared by mechanical alloying technology,and Fe-Al powder was dispersed into unsaturated polyester (UP) with different contents as absorber to form mixture Fe-Al-UP.The results indicate that the alloying process is almost accomplished and most of the particles are nanometer.Meanwhile,the microwave absorbability of Fe-Al-UP samples in frequency from 0.3 MHz to 1.5 GHz was studied.The results indicate that the more the absorber,the better the absorbing property.The absorbing property of Fe-50Al-UP was slightly higher than Fe-28Al-UP.
基金the DREAM project of MOST,China(Grant No.2016YFC0600408)the Strategic Priority Research Program(B)of Chinese Academy of Sciences(Grant No.XDB18000000)the Program of the National Mineral Rock and Fossil Specimens Resource Center from MOST,China.
文摘Carbonate-bearing fluids widely exist in different geological settings,and play important roles in transporting some elements such as the rare earth elements.They may be trapped as large or small fluid inclusions(with the size down to<1μm sometimes),and record critical physical-chemical signals for the formations of their host minerals.Spectroscopic methods like Raman spectroscopy and infrared spectroscopy have been proposed as effective methods to quantify the carbonate concentrations of these fluid inclusions.Although they have some great technical advantages over the conventional microthermometry method,there are still some technical difficulties to overcome before they can be routinely used to solve relevant geological problems.The typical limitations include their interlaboratory difference and poor performance on micro fluid inclusions.This study prepared standard ion-distilled water and K_(2)CO_(3)aqueous solutions at different molarities(from 0.5 to 5.5 mol/L),measured densities,collected Raman and infrared spectra,and explored correlations between the K_(2)CO_(3)molarity and the spectroscopic features at ambient P-T conditions.The result confirms that the Raman O-H stretching mode can be used as an internal standard to determine the carbonate concentrations despite some significant differences among the correlations,established in different laboratories,between the relative Raman intensity of the C-O symmetric stretching mode and that of the O-H stretching mode.It further reveals that the interlaboratory difference can be readily removed by performing one high-quality calibration experiment,provided that later quantifying analyses are conducted using the same Raman spectrometer with the same analytical conditions.Our infrared absorption data were collected from thin fluid films(thickness less than~2μm)formed by pressing the prepared solutions in a Microcompression Cell with two diamond-II plates.The data show that both the O-H stretching mode and the O-H bending mode can be used as internal standards to determine the carbonate concentrations.Since the IR signals of the C-O antisymmetric stretching vibration of the CO32ion,and the O-H stretching and bending vibrations from our thin films are very strong,their relative IR absorbance intensity,if well calibrated,can be used to investigate the micron-sized carbonate-bearing aqueous fluid inclusions.This study establishes the first calibration of this kind,which may have some applications.Additionally,our spectroscopic data suggest that as the K_(2)CO_(3)concentration increases the aqueous solution forms more large water molecule clusters via more intense hydrogen-bonding.This process may significantly alter the physical and chemical behavior of the fluids.
文摘Near-infrared (NIR) spectroscopy was applied to reagent-free quantitative analysis of polysaccharide of a brand product of proprietary Chinese medicine (PCM) oral solution samples. A novel method, called absorbance upper optimization partial least squares (AUO-PLS), was proposed and successfully applied to the wavelength selection. Based on varied partitioning of the calibration and prediction sample sets, the parameter optimization was performed to achieve stability. On the basis of the AUO-PLS method, the selected upper bound of appropriate absorbance was 1.53 and the corresponding wavebands combination was 400 - 1880 & 2088 - 2346 nm. With the use of random validation samples excluded from the modeling process, the root-mean-square error and correlation coefficient of prediction for polysaccharide were 27.09 mg·L<sup>-</sup><sup>1</sup> and 0.888, respectively. The results indicate that the NIR prediction values are close to those of the measured values. NIR spectroscopy combined with AUO-PLS method provided a promising tool for quantification of the polysaccharide for PCM oral solution and this technique is rapid and simple when compared with conventional methods.
文摘In this article, we investigate the global behavior of weak solutions of a simplified Ericksen-Leslie system for compressible flows of nematic liquid crystals in time in a bounded three-dimension domain-arbitrary forces. By adapting the arguments for the compressible Navier-Stokes equations, and carefully analyzing the direction field of liquid crystals in the equations of angular momentum, we show the existence of bounded absorbing sets, global bounded trajectories, and global attractors to weak solutions of compressible flows of nematic liquid crystals with the adiabatic constant γ〉5/3.
文摘Boundary procedure is an important phenomenon in numerical simulation. To reduce or eliminate the spurious reflections significantly which is occurred in boundary is a challenging and vital approach. The appropriate artificial numerical boundaries can be applied to eliminate the effect of unnecessary spurious reflections in case of the numerical simulations of wave propagation phenomena problems. Typically, to reduce the artificial reflections, the absorbing boundary conditions are necessary. In this paper, we overview and investigate the appropriate typical absorbing boundary conditions and analyzed the boundary effect of two dimensional wave equation numerically. Reflections over the wide-ranging incident angles are complicated to eliminate, but the absorbing boundary conditions that we have applied are computationally cost efficient, easy to apply and able to reduce reflections significantly. For numerical solution, finite difference method is applied to develop numerical scheme using 2D wave equation. Using the developed numerical scheme, we obtain the numerical solution of the governing equation as an initial boundary value problem and realize the qualitative behavior of the solution in infinite space. The finite difference numerical scheme has been investigated by developing MATLAB programming language code. Numerical results have been discussed and analyzed with presenting different qualitative behavior of the numerical scheme. The accuracy and efficiency of the numerical scheme has been illustrated. The stability analysis was discussed and verified stability condition. Using the numerical scheme and absorbing boundary conditions, the boundary effects and absorption of spurious reflection of boundary have been demonstrated.
基金Project(50473064) supported by the National Natural Science Foundation of China Project(040A02) supported by the Key Science Foundation of Shanghai Higher Education, China
文摘11 oxides (MgO, CaO, BaO, TiO2, V2O5, MnO2, Fe2O3, CuO, ZnO, PbO2 and B2O3), often found in coal-derived carbon materials, were loaded into the coal-derived carbon material by two methods such as adsorbing oxides through solution onto the surface of coke and adding oxides into the coal before carbonization. The effects of oxides on carbon solution reaction of carbon material were investigated and compared. The results show that the effect trends are similar but the effect of oxides by adsorbing is remarkably greater than that of the oxides by adding oxides as BaO, MgO, Fe2O3, CuO, ZnO, MnO2, PbO2 and B2O3. And the effect trends are similar. BaO, CaO and Fe2O3 are the greatest affecting oxides. The saturation point of addition content is 3% and that of adsorption is 1%.
