Missing data are a problem in geophysical surveys, and interpolation and reconstruction of missing data is part of the data processing and interpretation. Based on the sparseness of the geophysical data or the transfo...Missing data are a problem in geophysical surveys, and interpolation and reconstruction of missing data is part of the data processing and interpretation. Based on the sparseness of the geophysical data or the transform domain, we can improve the accuracy and stability of the reconstruction by transforming it to a sparse optimization problem. In this paper, we propose a mathematical model for the sparse reconstruction of data based on the LO-norm minimization. Furthermore, we discuss two types of the approximation algorithm for the LO- norm minimization according to the size and characteristics of the geophysical data: namely, the iteratively reweighted least-squares algorithm and the fast iterative hard thresholding algorithm. Theoretical and numerical analysis showed that applying the iteratively reweighted least-squares algorithm to the reconstruction of potential field data exploits its fast convergence rate, short calculation time, and high precision, whereas the fast iterative hard thresholding algorithm is more suitable for processing seismic data, moreover, its computational efficiency is better than that of the traditional iterative hard thresholding algorithm.展开更多
The inversions of complex geophysical data always solve multi-parameter, nonlinear, and multimodal optimization problems. Searching for the optimal inversion solutions is similar to the social behavior observed in swa...The inversions of complex geophysical data always solve multi-parameter, nonlinear, and multimodal optimization problems. Searching for the optimal inversion solutions is similar to the social behavior observed in swarms such as birds and ants when searching for food. In this article, first the particle swarm optimization algorithm was described in detail, and ant colony algorithm improved. Then the methods were applied to three different kinds of geophysical inversion problems: (1) a linear problem which is sensitive to noise, (2) a synchronous inversion of linear and nonlinear problems, and (3) a nonlinear problem. The results validate their feasibility and efficiency. Compared with the conventional genetic algorithm and simulated annealing, they have the advantages of higher convergence speed and accuracy. Compared with the quasi-Newton method and Levenberg-Marquardt method, they work better with the ability to overcome the locally optimal solutions.展开更多
A comprehensive study of the data profiles, including the 2D seismic data, single channel seismic data, shallow sections, etc., reveals that gas hydrates occur in the East China Sea. A series of special techniques are...A comprehensive study of the data profiles, including the 2D seismic data, single channel seismic data, shallow sections, etc., reveals that gas hydrates occur in the East China Sea. A series of special techniques are used in the processing of seismic data, which include enhancing the accuracy of velocity analysis and resolution, estimating the wavelet, suppressing the multiple, preserving the relative amplitude, using the DMO and AVO techniques and some special techniques in dealing with the wave impedance. The existence of gas hydrates is reflected in the subbottom profiles in the appearance of BSRs, amplitude anomalies, velocity anomalies and AVO anomalies, etc. Hence the gas hydrates can be identified and predicted. It is pointed out that the East China Sea is a favorable area of the gas hydrates resource, and the Okinawa Trough is a target area of gas hydrates reservoir.展开更多
Recent geochemical and geophysical data from the Moon enable a revision of earlier interpretations regarding lunar origin, structure and bulk composition. Earth and Moon show many similarities among their isotopic com...Recent geochemical and geophysical data from the Moon enable a revision of earlier interpretations regarding lunar origin, structure and bulk composition. Earth and Moon show many similarities among their isotopic compositions, but they have evolved in totally dissimilar ways, probably related to the deficiency of water and volatile elements in the Moon as well as the vast differences in size and internal pressure. Some global geochemical differences from the Earth such as volatile depletion based on K/U ratios have been established. However, all current lunar samples come from differentiated regions, making the establishment of a bulk composition more reliant on bulk geophysical properties or isotopic similarities; it remains unclear how the latter arose or relate to whole Moon composition. The lack of fractionation effects among the refractory and super-refractory elements indicates that the proto-lunar material seems unlikely to have been vaporized while the presence of volatile elements may place lower limits on proto-lunar temperatures. The apparent lack of geochemical evidence of an impacting body enables other possible impactors, such as comets, to be considered. Although the origin of the Moon remains currently unknown, it is generally believed that the Moon originated as the result of a giant impact on the Earth.展开更多
In this paper, the physical education information teaching design system is researched and developed based on VB6.0 optimization platform. According to the national physical education and health course standards and t...In this paper, the physical education information teaching design system is researched and developed based on VB6.0 optimization platform. According to the national physical education and health course standards and the fundamental theories of the constructivisrn, the author adopts the modular-design development method to design two functional areas which are the displaying of the teaching design contents and the online information database (nine modules in total) on the basis of the P.E. teaching design flow. Importantly, this system features the compatibility, scalability and practical applicability, and can effectively improve the ability of P.E. teachers to design their teaching, and hence provides a guarantee for the improvement of teaching quality and efficiency.展开更多
A set of experimental data obtained at the Institute of Physics and Power Engineering in a vertical bundle cooled with supercritical R-12 was analyzed. The test section was a 7-element bundle installed in a hexagonal ...A set of experimental data obtained at the Institute of Physics and Power Engineering in a vertical bundle cooled with supercritical R-12 was analyzed. The test section was a 7-element bundle installed in a hexagonal flow channel with three grid spacers. Data was collected at pressures of approximately 4.65 MPa for several different combinations of wall and bulk-fluid temperatures that were below, at, or above pseudocritical conditions. Analysis of the data has confirmed that there are three distinct heat-transfer regimes for forced convention in supercritical fluids: (1) normal heat transfer, (2) deteriorated heat transfer, and (3) enhanced heat transfer. It was also confirmed that the effects of spacers are evident which was previously observed in sub-critical experimental data. This work compares the wall and bulk fluid temperature data of the experiments to predictions based upon current 1-D correlations for heat transfer in supercritical fluids.展开更多
An equation of state (EOS) for high-pressure liquids, i.e., Tait EOS, is deduced according to isothermal 1 3V compressibility KT= -1/V· (2V/2p)T·.Based on the equation, a generalized EOS for high pressu...An equation of state (EOS) for high-pressure liquids, i.e., Tait EOS, is deduced according to isothermal 1 3V compressibility KT= -1/V· (2V/2p)T·.Based on the equation, a generalized EOS for high pressure-liquids is established by using the reduced state principle and introducing a characteristic parameter-configuration factor ξ. Reasonably satisfactory P-V-T data for many organic compounds, including some polar components, were calculated by using the equation.展开更多
The present study was designed to determine the chemical constituents of the stem tuber of Pinellia pedatisecta. The chemical constituents were isolated and purified by various chromatographic techniques, and their st...The present study was designed to determine the chemical constituents of the stem tuber of Pinellia pedatisecta. The chemical constituents were isolated and purified by various chromatographic techniques, and their structures were elucidated on the basis of physicochemical properties and spectral data. Three new alkaloids(compounds 1, 2, and 3) were obtained and identified as 9-((5-methoxypyridin-2-yl)methyl)-9 H-purin-6-amine(1), 4-(2-(2, 5-dioxopyrrolidin-1-yl)ethyl)phenyl acetate(2), and N-(9-((5-methoxypyridin-2-yl)methyl)-9 H-purin-6-yl)acetamide(3). These compounds were evaluated for their cytotoxicity against human cervical cancer He La cells. Compounds 1 and 3 significantly inhibited the proliferation of He La cells with IC_(50) values being 3.02 ± 0.54 and 7.16 ± 0.62 μmol·L^(-1), respectively.展开更多
Accurate estimation of evapotranspiration(ET),especially at the regional scale,is an extensively investigated topic in the field of water science. The ability to obtain a continuous time series of highly precise ET va...Accurate estimation of evapotranspiration(ET),especially at the regional scale,is an extensively investigated topic in the field of water science. The ability to obtain a continuous time series of highly precise ET values is necessary for improving our knowledge of fundamental hydrological processes and for addressing various problems regarding the use of water. This objective can be achieved by means of ET data assimilation based on hydrological modeling. In this paper,a comprehensive review of ET data assimilation based on hydrological modeling is provided. The difficulties and bottlenecks of using ET,being a non-state variable,to construct data assimilation relationships are elaborated upon,with a discussion and analysis of the feasibility of assimilating ET into various hydrological models. Based on this,a new easy-to-operate ET assimilation scheme that includes a water circulation physical mechanism is proposed. The scheme was developed with an improved data assimilation system that uses a distributed time-variant gain model(DTVGM),and the ET-soil humidity nonlinear time response relationship of this model. Moreover,the ET mechanism in the DTVGM was improved to perfect the ET data assimilation system. The new scheme may provide the best spatial and temporal characteristics for hydrological states,and may be referenced for accurate estimation of regional evapotranspiration.展开更多
With unique physical and chemical properties, aqueous solutions in the mantle may play important roles for a number of geochemical and geodynamical processes. However, since experimental data available are very limite...With unique physical and chemical properties, aqueous solutions in the mantle may play important roles for a number of geochemical and geodynamical processes. However, since experimental data available are very limited, people still know little about the aqueous solutions and their interactions with surrounding rocks and melts. From the perspective of thermodynamics, equation of state(EOS) is the key to push forward the modeling of aqueous solutions. Nevertheless, up to now accurate EOSs suitable for the mantle conditions are still in shortage. With discussions over several recognized EOSs, we summarize several ways to enhance the predictability of EOS: utilizing high quality data from molecular simulations, choosing functions with sound physical background, and improving the regression procedures for the empirical parameters. In the meantime, we find that the ion-bearing systems are still the focus of challenges in this area. New developments of experiments and computer simulations effectively deal with these challenges and in-depth understandings of aqueous solutions in the mantle are expected in the near future.展开更多
Functional proteomics can be defined as a strategy to couple proteomic information with biochemical and physiological analyses with the aim of understanding better the functions of proteins in normal and diseased orga...Functional proteomics can be defined as a strategy to couple proteomic information with biochemical and physiological analyses with the aim of understanding better the functions of proteins in normal and diseased organs.In recent years,a variety of publicly available bioinformatics databases have been developed to support protein-related information management and biological knowledge discovery.In addition to being used to annotate the proteome,these resources also offer the opportunity to develop global approaches to the study of the functional role of proteins both in health and disease.Here,we present a comprehensive review of the major human protein bioinformatics databases.We conclude this review by discussing a few examples that illustrate the importance of these databases in functional proteomics research.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.41074133)
文摘Missing data are a problem in geophysical surveys, and interpolation and reconstruction of missing data is part of the data processing and interpretation. Based on the sparseness of the geophysical data or the transform domain, we can improve the accuracy and stability of the reconstruction by transforming it to a sparse optimization problem. In this paper, we propose a mathematical model for the sparse reconstruction of data based on the LO-norm minimization. Furthermore, we discuss two types of the approximation algorithm for the LO- norm minimization according to the size and characteristics of the geophysical data: namely, the iteratively reweighted least-squares algorithm and the fast iterative hard thresholding algorithm. Theoretical and numerical analysis showed that applying the iteratively reweighted least-squares algorithm to the reconstruction of potential field data exploits its fast convergence rate, short calculation time, and high precision, whereas the fast iterative hard thresholding algorithm is more suitable for processing seismic data, moreover, its computational efficiency is better than that of the traditional iterative hard thresholding algorithm.
基金supported by the 973 Program(Grant No 2007CB209600)Open Fund(No.GDL0706) of the Key Laboratory of Geo-detection(China University of Geosciences,Beijing),Ministry of Education
文摘The inversions of complex geophysical data always solve multi-parameter, nonlinear, and multimodal optimization problems. Searching for the optimal inversion solutions is similar to the social behavior observed in swarms such as birds and ants when searching for food. In this article, first the particle swarm optimization algorithm was described in detail, and ant colony algorithm improved. Then the methods were applied to three different kinds of geophysical inversion problems: (1) a linear problem which is sensitive to noise, (2) a synchronous inversion of linear and nonlinear problems, and (3) a nonlinear problem. The results validate their feasibility and efficiency. Compared with the conventional genetic algorithm and simulated annealing, they have the advantages of higher convergence speed and accuracy. Compared with the quasi-Newton method and Levenberg-Marquardt method, they work better with the ability to overcome the locally optimal solutions.
文摘A comprehensive study of the data profiles, including the 2D seismic data, single channel seismic data, shallow sections, etc., reveals that gas hydrates occur in the East China Sea. A series of special techniques are used in the processing of seismic data, which include enhancing the accuracy of velocity analysis and resolution, estimating the wavelet, suppressing the multiple, preserving the relative amplitude, using the DMO and AVO techniques and some special techniques in dealing with the wave impedance. The existence of gas hydrates is reflected in the subbottom profiles in the appearance of BSRs, amplitude anomalies, velocity anomalies and AVO anomalies, etc. Hence the gas hydrates can be identified and predicted. It is pointed out that the East China Sea is a favorable area of the gas hydrates resource, and the Okinawa Trough is a target area of gas hydrates reservoir.
文摘Recent geochemical and geophysical data from the Moon enable a revision of earlier interpretations regarding lunar origin, structure and bulk composition. Earth and Moon show many similarities among their isotopic compositions, but they have evolved in totally dissimilar ways, probably related to the deficiency of water and volatile elements in the Moon as well as the vast differences in size and internal pressure. Some global geochemical differences from the Earth such as volatile depletion based on K/U ratios have been established. However, all current lunar samples come from differentiated regions, making the establishment of a bulk composition more reliant on bulk geophysical properties or isotopic similarities; it remains unclear how the latter arose or relate to whole Moon composition. The lack of fractionation effects among the refractory and super-refractory elements indicates that the proto-lunar material seems unlikely to have been vaporized while the presence of volatile elements may place lower limits on proto-lunar temperatures. The apparent lack of geochemical evidence of an impacting body enables other possible impactors, such as comets, to be considered. Although the origin of the Moon remains currently unknown, it is generally believed that the Moon originated as the result of a giant impact on the Earth.
文摘In this paper, the physical education information teaching design system is researched and developed based on VB6.0 optimization platform. According to the national physical education and health course standards and the fundamental theories of the constructivisrn, the author adopts the modular-design development method to design two functional areas which are the displaying of the teaching design contents and the online information database (nine modules in total) on the basis of the P.E. teaching design flow. Importantly, this system features the compatibility, scalability and practical applicability, and can effectively improve the ability of P.E. teachers to design their teaching, and hence provides a guarantee for the improvement of teaching quality and efficiency.
文摘A set of experimental data obtained at the Institute of Physics and Power Engineering in a vertical bundle cooled with supercritical R-12 was analyzed. The test section was a 7-element bundle installed in a hexagonal flow channel with three grid spacers. Data was collected at pressures of approximately 4.65 MPa for several different combinations of wall and bulk-fluid temperatures that were below, at, or above pseudocritical conditions. Analysis of the data has confirmed that there are three distinct heat-transfer regimes for forced convention in supercritical fluids: (1) normal heat transfer, (2) deteriorated heat transfer, and (3) enhanced heat transfer. It was also confirmed that the effects of spacers are evident which was previously observed in sub-critical experimental data. This work compares the wall and bulk fluid temperature data of the experiments to predictions based upon current 1-D correlations for heat transfer in supercritical fluids.
文摘An equation of state (EOS) for high-pressure liquids, i.e., Tait EOS, is deduced according to isothermal 1 3V compressibility KT= -1/V· (2V/2p)T·.Based on the equation, a generalized EOS for high pressure-liquids is established by using the reduced state principle and introducing a characteristic parameter-configuration factor ξ. Reasonably satisfactory P-V-T data for many organic compounds, including some polar components, were calculated by using the equation.
基金supported by the National Natural Science Foundation of China(No.81373964)Introduction Program of Scientific Researcher of Sichuan University of Science&Engineering(Nos.2016RCL07 and 2017RCL61)+2 种基金the Opening Project of Key Laboratory of Green Chemistry of Sichuan Institutes of Higher Education(No.LYJ1302)the Scientific Research Fund of the Sichuan Provincial Education Department(No.13ZB0133)the Science and Technology Program Project of Sichuan(No.2015JY0024)
文摘The present study was designed to determine the chemical constituents of the stem tuber of Pinellia pedatisecta. The chemical constituents were isolated and purified by various chromatographic techniques, and their structures were elucidated on the basis of physicochemical properties and spectral data. Three new alkaloids(compounds 1, 2, and 3) were obtained and identified as 9-((5-methoxypyridin-2-yl)methyl)-9 H-purin-6-amine(1), 4-(2-(2, 5-dioxopyrrolidin-1-yl)ethyl)phenyl acetate(2), and N-(9-((5-methoxypyridin-2-yl)methyl)-9 H-purin-6-yl)acetamide(3). These compounds were evaluated for their cytotoxicity against human cervical cancer He La cells. Compounds 1 and 3 significantly inhibited the proliferation of He La cells with IC_(50) values being 3.02 ± 0.54 and 7.16 ± 0.62 μmol·L^(-1), respectively.
基金National Key Basic Research Program of China(973 Program),No.2015CB452701National Natural Science Foundation of China,No.41271003+1 种基金No.41371043No.41401042
文摘Accurate estimation of evapotranspiration(ET),especially at the regional scale,is an extensively investigated topic in the field of water science. The ability to obtain a continuous time series of highly precise ET values is necessary for improving our knowledge of fundamental hydrological processes and for addressing various problems regarding the use of water. This objective can be achieved by means of ET data assimilation based on hydrological modeling. In this paper,a comprehensive review of ET data assimilation based on hydrological modeling is provided. The difficulties and bottlenecks of using ET,being a non-state variable,to construct data assimilation relationships are elaborated upon,with a discussion and analysis of the feasibility of assimilating ET into various hydrological models. Based on this,a new easy-to-operate ET assimilation scheme that includes a water circulation physical mechanism is proposed. The scheme was developed with an improved data assimilation system that uses a distributed time-variant gain model(DTVGM),and the ET-soil humidity nonlinear time response relationship of this model. Moreover,the ET mechanism in the DTVGM was improved to perfect the ET data assimilation system. The new scheme may provide the best spatial and temporal characteristics for hydrological states,and may be referenced for accurate estimation of regional evapotranspiration.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41590620 & 41473060)
文摘With unique physical and chemical properties, aqueous solutions in the mantle may play important roles for a number of geochemical and geodynamical processes. However, since experimental data available are very limited, people still know little about the aqueous solutions and their interactions with surrounding rocks and melts. From the perspective of thermodynamics, equation of state(EOS) is the key to push forward the modeling of aqueous solutions. Nevertheless, up to now accurate EOSs suitable for the mantle conditions are still in shortage. With discussions over several recognized EOSs, we summarize several ways to enhance the predictability of EOS: utilizing high quality data from molecular simulations, choosing functions with sound physical background, and improving the regression procedures for the empirical parameters. In the meantime, we find that the ion-bearing systems are still the focus of challenges in this area. New developments of experiments and computer simulations effectively deal with these challenges and in-depth understandings of aqueous solutions in the mantle are expected in the near future.
基金supported by the National Basic Research Program of China (Grant Nos. 2010CB912700 and 2011CB910601)
文摘Functional proteomics can be defined as a strategy to couple proteomic information with biochemical and physiological analyses with the aim of understanding better the functions of proteins in normal and diseased organs.In recent years,a variety of publicly available bioinformatics databases have been developed to support protein-related information management and biological knowledge discovery.In addition to being used to annotate the proteome,these resources also offer the opportunity to develop global approaches to the study of the functional role of proteins both in health and disease.Here,we present a comprehensive review of the major human protein bioinformatics databases.We conclude this review by discussing a few examples that illustrate the importance of these databases in functional proteomics research.