An approach to contour extraction and feature point detection in the 3-D fragment reassembly is proposed. A simple and effective technique is used for building the intrinsic topology of the fragment data suitable for ...An approach to contour extraction and feature point detection in the 3-D fragment reassembly is proposed. A simple and effective technique is used for building the intrinsic topology of the fragment data suitable for contour extraction. For the scanned data in which the topology is difficult to be achieved, the corresponding solutions are given to manage this problem. A robust approach is used for the curvature and torsion calculation of the discrete contour in a 3-D space. Finally, a method is developed for detecting feature points of the fragment contour based on total curvature. Therefore, the contour description combines the simple global information with local feature points. Experiments with real contour curves extracted from 3-D fragments demonstrate that the proposed method is robust and efficient.展开更多
A systematic scheme is proposed to automatically extract geometric surface features from a point cloud composed of a set of unorganized three-dimensional coordinate points by data segmentation. The key technology is a...A systematic scheme is proposed to automatically extract geometric surface features from a point cloud composed of a set of unorganized three-dimensional coordinate points by data segmentation. The key technology is a algorithm that estimates the local surface curvature properties of scattered point data based on local base surface parameterization. Eight surface types from the signs of the Gaussian and mean curvatures provide an initial segmentation, which will be refined by an iterative region growing method. Experimental results show the scheme's performance on two point clouds.展开更多
Seismic data contain random noise interference and are affected by irregular subsampling. Presently, most of the data reconstruction methods are carried out separately from noise suppression. Moreover, most data recon...Seismic data contain random noise interference and are affected by irregular subsampling. Presently, most of the data reconstruction methods are carried out separately from noise suppression. Moreover, most data reconstruction methods are not ideal for noisy data. In this paper, we choose the multiscale and multidirectional 2D curvelet transform to perform simultaneous data reconstruction and noise suppression of 3D seismic data. We introduce the POCS algorithm, the exponentially decreasing square root threshold, and soft threshold operator to interpolate the data at each time slice. A weighing strategy was introduced to reduce the reconstructed data noise. A 3D simultaneous data reconstruction and noise suppression method based on the curvelet transform was proposed. When compared with data reconstruction followed by denoizing and the Fourier transform, the proposed method is more robust and effective. The proposed method has important implications for data acquisition in complex areas and reconstructing missing traces.展开更多
[Objective] This study aimed to clarify the correlation between changes of Apis mel ifera and the nectar secretion characteristics of nectariferous plants. [Method] Considering the nectar secretion characteristics of ...[Objective] This study aimed to clarify the correlation between changes of Apis mel ifera and the nectar secretion characteristics of nectariferous plants. [Method] Considering the nectar secretion characteristics of major and auxiliary nec-tariferous plants, six Apis mel ifera colonies were selected for measure the number of eggs, larvae, pupae and adult bees from Jan. to Dec. in 2012; based on that, their annual change curves were also plotted. [Result] The results showed that there were three peaks of the total number of A. mel ifera workers throughout the year:the first occurred on May 15th, with bees developed into an ideal population for col-lecting pomegranate nectar, and the second and third peaks occurred on July 15th and Oct. 15th, respectively, with bees developed into an ideal population for col ect-ing E. ciliate (Thuab) Hyland. [Conclusion] Prevention of Varroa jacobsoni should be carried out with two or more types of acaricides at the late nectar flow stages of the two nectariferous plants(pomegranate and E. ciliate (Thuab) Hyland) when there was a nectar deficiency. Prevention of Tropilaelaps clareae should be timely per-formed with sublimed sulfur in conjunction with acaricides. This study provides a theoretical basis for the high-quality and high-yielding production of honey, as wel as for the product safety.展开更多
In seismic prospecting, fi eld conditions and other factors hamper the recording of the complete seismic wavefi eld; thus, data interpolation is critical in seismic data processing. Especially, in complex conditions, ...In seismic prospecting, fi eld conditions and other factors hamper the recording of the complete seismic wavefi eld; thus, data interpolation is critical in seismic data processing. Especially, in complex conditions, prestack missing data affect the subsequent highprecision data processing workfl ow. Compressive sensing is an effective strategy for seismic data interpolation by optimally representing the complex seismic wavefi eld and using fast and accurate iterative algorithms. The seislet transform is a sparse multiscale transform well suited for representing the seismic wavefield, as it can effectively compress seismic events. Furthermore, the Bregman iterative algorithm is an efficient algorithm for sparse representation in compressive sensing. Seismic data interpolation methods can be developed by combining seismic dynamic prediction, image transform, and compressive sensing. In this study, we link seismic data interpolation and constrained optimization. We selected the OC-seislet sparse transform to represent complex wavefields and used the Bregman iteration method to solve the hybrid norm inverse problem under the compressed sensing framework. In addition, we used an H-curve method to choose the threshold parameter in the Bregman iteration method. Thus, we achieved fast and accurate reconstruction of the seismic wavefi eld. Model and fi eld data tests demonstrate that the Bregman iteration method based on the H-curve norm in the sparse transform domain can effectively reconstruct missing complex wavefi eld data.展开更多
Digital elevation model (DEM) is the most popular product for three-dimensional (3D) digital representation of bare Earth surface and can be produced by many techniques with different characteristics and ground sa...Digital elevation model (DEM) is the most popular product for three-dimensional (3D) digital representation of bare Earth surface and can be produced by many techniques with different characteristics and ground sampling distances (GSD). Space-borne opti- cal and synthetic aperture radar (SAR) imaging are two of the most preferred and modern techniques for DEM generation. Using them, global DEMs that cover almost entire Earth are produced with low cost and time saving processing. In this study, we aimed to assess the Satellite pour robservation de la Terre-5 (SPOT-5), High Resolution Stereoscopic (HRS), the Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER), and the Shuttle Radar Topography Mission (SRTM) C-band global DEMs, produced with space-borne optical and SAR imaging. For the assessment, a reference DEM derived from 1 : 1000 scaled digital photogrammetric maps was used. The study is performed in 100 km2 study area in Istanbul including various land classes such as open land, forest, built-up land, scrub and rough terrain obtained from Landsat data. The analyses were realized considering three vertical accuracy types as fundamental, supplemental, and consolidated, defined by national digital elevation program (NDEP) of USA. The results showed that, vertical accuracy of SRTM C-band DEM is better than optical models in all three accuracy types despite having the largest grid spacing. The result of SPOT-5 HRS DEM is very close by SRTM and superior in comparison with ASTER models.展开更多
The CifNet network multi-well data management system is developed for 100MB or 1000MB local network environments which are used in Chinese oil industry. The kernel techniques of CifNet system include: 1, establishing ...The CifNet network multi-well data management system is developed for 100MB or 1000MB local network environments which are used in Chinese oil industry. The kernel techniques of CifNet system include: 1, establishing a high efficient and low cost network multi-well data management architecture based on the General Logging Curve Theory and the Cif data format; 2, implementing efficient visit and transmission of multi-well data in C/S local network based on TCP/IP protocol; 3,ensuring the safety of multi-well data in store, visit and application based on Unix operating system security. By using CifNet system, the researcher in office or at home can visit curves of any borehole in any working area of any oilfield. The application foreground of CifNet system is also commented.展开更多
AIM To investigate whether promoter methylation is re-sponsible for the silencing of formin 2 ( FMN2) in colorectal cancer (CRC) and to analyze the association between FMN2 methylation and CRC.METHODSWe frst ident...AIM To investigate whether promoter methylation is re-sponsible for the silencing of formin 2 ( FMN2) in colorectal cancer (CRC) and to analyze the association between FMN2 methylation and CRC.METHODSWe frst identifed the expression levels and methylation levels of FMN2 in large-scale human CRC expression data-sets, including GEO and TCGA, and analyzed the relation-ship between the expression and methylation levels. Then, the methylation levels in four CpG regions adjacent to the FMN2 promoter were assessed by MethylTarget? assays in CRC cells and in paired colorectal tumor samples and adjacent nontumor tissue samples. Furthermore, we inhibited DNA methylation in CRC cells with 5-Aza-2’-deoxycytidine and assessed the expression of FMN2 by qRT-PCR. Last, the association between FMN2 methylation patterns and clinical indicators was analyzed.RESULTSA statistically significant downregulation of FMN2 ex-pression in large-scale human CRC expression datasets was found. Subsequent analysis showed that a high frequency of hypermethylation occurred in the FMN2 gene promoter in CRC tissues; operating characteristic curve analysis revealed that FMN2 gene methylation had a good capability for discriminating between CRC and nontumor tissue samples (AUC = 0.8432, P 〈 0.0001). MethylTarget? assays showed that CRC cells and tissues displayed higher methylation of these CpG regions than nontumor tissue samples. Correlation analysis showed a strong inverse correlation between methylation and FMN2 expression, and the inhibition of DNA methylation with 5-Aza significantly increased endogenous FMN2 expression. Analysis of the association between FMN2 methylation patterns and clinical indicators showed that FMN2 methylation was signifcantly associated with age, N stage, lymphovascular invasion, and pathologic tumor stage. Notably, the highest methylation of FMN2 occurred in tissues from cases of early-stage CRC, including cases with no regional lymph node metastasis (N0), cases in stages Ⅰ and Ⅱ, and cases with no lymphovascular inva-sion, but the methylation level began to decrease with tumor progression. Additionally, FMN2 promoter hyper-methylation was more common in patients 〉 60 years old and in colon cancer tissue.CONCLUSIONFMN2 promoter hypermethylation may be an important early event in CRC, most likely playing a critical role in cancer initiation, and can serve as an ideal diagnostic biomarker in elderly patients with early-stage colon cancer.展开更多
A novel Hilbert-curve is introduced for parallel spatial data partitioning, with consideration of the huge-amount property of spatial information and the variable-length characteristic of vector data items. Based on t...A novel Hilbert-curve is introduced for parallel spatial data partitioning, with consideration of the huge-amount property of spatial information and the variable-length characteristic of vector data items. Based on the improved Hilbert curve, the algorithm can be designed to achieve almost-uniform spatial data partitioning among multiple disks in parallel spatial databases. Thus, the phenomenon of data imbalance can be significantly avoided and search and query efficiency can be enhanced.展开更多
Research into the characteristics of geothermal fields is important for the control of heat damage in mines. Based on measured geothermal data of boreholes from 200 m to 1200 m in a Jiahe Coal Mine, we demonstrate non...Research into the characteristics of geothermal fields is important for the control of heat damage in mines. Based on measured geothermal data of boreholes from 200 m to 1200 m in a Jiahe Coal Mine, we demonstrate non-linear but increasing relations of both geo-temperatures and geothermal gradients with increases depth. Numerically, we fitted the relationship between geo-temperatures and depth, a first-order exponential decay curve, formulated as: T(h) = 4.975 + 23.08 exp(h/1736.1).展开更多
An assistant surface was constructed on the base of boundary that being auto-matically extracted from the scattered data.The parameters of every data point corre-sponding to the assistant surface and their applied fie...An assistant surface was constructed on the base of boundary that being auto-matically extracted from the scattered data.The parameters of every data point corre-sponding to the assistant surface and their applied fields were calculated respectively.Inevery applied region,a surface patch was constructed by a special Hermite interpolation.The final surface can be obtained by a piecewise bicubic Hermite interpolation in the ag-gregate of applied regions of metrical data.This method avoids the triangulation problem.Numerical results indicate that it is efficient and accurate.展开更多
The beam-to-column semirigid connection in a steel frame structure is represented by a zero-length rotational spring at the end of the beam element. The beam-to-column semirigid connection behavior is represented by i...The beam-to-column semirigid connection in a steel frame structure is represented by a zero-length rotational spring at the end of the beam element. The beam-to-column semirigid connection behavior is represented by its moment-rotation relationship. Several traditional mathematical models have been proposed to fit the moment-rotation curves from the experimental database,but they may be more reliable within certain ranges. In this paper, the intellectualized analytical model is proposed in the semirigid connections for top and seat angles with double web angles using the feed-forward back-propagation artificial neural network (BP-ANN) technique. the intellectualized analytical model from experimental results based on BP-ANN is more reliable and it is a better choice to the moment-rotation curves for beam-to-column semirigid connection. The results are found to provide effectiveness to the experimental response that is satisfactory for use in steel structural engineering design.展开更多
This paper investigates the regional distribution and pollution of energyintensive industries in China. Through the analysis of provincial panel data collected during 1998-2008, this work estimates the drivers of poll...This paper investigates the regional distribution and pollution of energyintensive industries in China. Through the analysis of provincial panel data collected during 1998-2008, this work estimates the drivers of pollution in 30 of China's provincial-level divisions. The paper concludes that while China's energy-intensive industries are heavily distributed in eastern and central China, the speed of development toward central and western China has, in recent years, risen continuously. Industries located in eastern China do, however, remain the primary polluters in the country. Notably, regional agglomeration of energy-intensive industries plays a positive role in energy conservation and pollution control in China. This paper also finds that patterns of pollution in China follow the environmental Kuznets curve (EKC) with strong inter-provincial discrepancies.展开更多
The critical curves for binary systems of methane combined with nitrogen, carbon monoxide, carbon dioxide, ethane, propane, butane and water at temperatures from 125 K to 650 K and pressures from 3.5 MPa to 250 MPa we...The critical curves for binary systems of methane combined with nitrogen, carbon monoxide, carbon dioxide, ethane, propane, butane and water at temperatures from 125 K to 650 K and pressures from 3.5 MPa to 250 MPa were calculated by using Heilig-Franck equation of state. This equation of state contains a repulsion term and an attraction term for intermolecular interaction. With pairwise combination rules for these potentials, three adjustable parameters are needed. The results showed that the critical curves of the former six binary systems belonged to type I, and CH4+H2O system belonged to type III. The calculated data were compared with the experimental data,which yielded good results for the pressure-temperature, pressure-composition and temperature-composition behaviors of the seven systems. Moreover, the values of the adjustable parameters were obtained from the calculation of the critical curves. They can also be used for other relevant calculation.展开更多
Based on the L,B and V statistics of the 106 ground feature groups or the 769 ground feature class units in the world presented in the part I of the paper,the distribution of the world ground features on the axes of L...Based on the L,B and V statistics of the 106 ground feature groups or the 769 ground feature class units in the world presented in the part I of the paper,the distribution of the world ground features on the axes of L,B and V,in the planes of L-B,L-V and B-V and in the space of L-B-V was discussed.And the typical numerical characteristics of the various ground features were also summarized.展开更多
On the basis of the historical statistics on power consumption, this paper anal)yes the power consumption trends in China by means of analyzing methods based on consumption proportion curve, fixed base curve, month-o...On the basis of the historical statistics on power consumption, this paper anal)yes the power consumption trends in China by means of analyzing methods based on consumption proportion curve, fixed base curve, month-on-month increase curve and fixed base index curve. Special attentions are paid to the consumption trend in the first half of 2010, and policy strategies are suggested targeting the problems reflected by the consumption trend.展开更多
In this paper, by using adequate stress-strain relationship, mesh elements, boundary conditions and loading conditions, the finite element ANSYS analysis on the behavior of circular tubes subjected to symmetrical cycl...In this paper, by using adequate stress-strain relationship, mesh elements, boundary conditions and loading conditions, the finite element ANSYS analysis on the behavior of circular tubes subjected to symmetrical cyclic bending with or without external pressure is discussed. The behavior includes the moment-curvature and ovalization-curvature relationships. In addition, the calculated ovalizations at two different sections, middle and right cross-sections, are also included. Experimental data for 6061-T6 aluminum alloy tubes subjected to cyclic bending with or without external pressure were compared with the ANSYS analysis. It has been shown that the analysis of the elastoplatic moment-curvature relationship and the symmetrical, ratcheting and increasing ovalization-curvature relationship is in good agreement with the experimental data.展开更多
文摘An approach to contour extraction and feature point detection in the 3-D fragment reassembly is proposed. A simple and effective technique is used for building the intrinsic topology of the fragment data suitable for contour extraction. For the scanned data in which the topology is difficult to be achieved, the corresponding solutions are given to manage this problem. A robust approach is used for the curvature and torsion calculation of the discrete contour in a 3-D space. Finally, a method is developed for detecting feature points of the fragment contour based on total curvature. Therefore, the contour description combines the simple global information with local feature points. Experiments with real contour curves extracted from 3-D fragments demonstrate that the proposed method is robust and efficient.
文摘A systematic scheme is proposed to automatically extract geometric surface features from a point cloud composed of a set of unorganized three-dimensional coordinate points by data segmentation. The key technology is a algorithm that estimates the local surface curvature properties of scattered point data based on local base surface parameterization. Eight surface types from the signs of the Gaussian and mean curvatures provide an initial segmentation, which will be refined by an iterative region growing method. Experimental results show the scheme's performance on two point clouds.
基金sponsored by the National Natural Science Foundation of China(Nos.41304097 and 41664006)the Natural Science Foundation of Jiangxi Province(No.20151BAB203044)+1 种基金the China Scholarship Council(No.201508360061)Distinguished Young Talent Foundation of Jiangxi Province(2017)
文摘Seismic data contain random noise interference and are affected by irregular subsampling. Presently, most of the data reconstruction methods are carried out separately from noise suppression. Moreover, most data reconstruction methods are not ideal for noisy data. In this paper, we choose the multiscale and multidirectional 2D curvelet transform to perform simultaneous data reconstruction and noise suppression of 3D seismic data. We introduce the POCS algorithm, the exponentially decreasing square root threshold, and soft threshold operator to interpolate the data at each time slice. A weighing strategy was introduced to reduce the reconstructed data noise. A 3D simultaneous data reconstruction and noise suppression method based on the curvelet transform was proposed. When compared with data reconstruction followed by denoizing and the Fourier transform, the proposed method is more robust and effective. The proposed method has important implications for data acquisition in complex areas and reconstructing missing traces.
基金Supported by the Key New Products Development Program of Science and Technology Agency of Yunnan Province(2011BB012)~~
文摘[Objective] This study aimed to clarify the correlation between changes of Apis mel ifera and the nectar secretion characteristics of nectariferous plants. [Method] Considering the nectar secretion characteristics of major and auxiliary nec-tariferous plants, six Apis mel ifera colonies were selected for measure the number of eggs, larvae, pupae and adult bees from Jan. to Dec. in 2012; based on that, their annual change curves were also plotted. [Result] The results showed that there were three peaks of the total number of A. mel ifera workers throughout the year:the first occurred on May 15th, with bees developed into an ideal population for col-lecting pomegranate nectar, and the second and third peaks occurred on July 15th and Oct. 15th, respectively, with bees developed into an ideal population for col ect-ing E. ciliate (Thuab) Hyland. [Conclusion] Prevention of Varroa jacobsoni should be carried out with two or more types of acaricides at the late nectar flow stages of the two nectariferous plants(pomegranate and E. ciliate (Thuab) Hyland) when there was a nectar deficiency. Prevention of Tropilaelaps clareae should be timely per-formed with sublimed sulfur in conjunction with acaricides. This study provides a theoretical basis for the high-quality and high-yielding production of honey, as wel as for the product safety.
基金supported by the National Natural Science Foundation of China(Nos.41274119,41174080,and 41004041)the 863 Program of China(No.2012AA09A20103)
文摘In seismic prospecting, fi eld conditions and other factors hamper the recording of the complete seismic wavefi eld; thus, data interpolation is critical in seismic data processing. Especially, in complex conditions, prestack missing data affect the subsequent highprecision data processing workfl ow. Compressive sensing is an effective strategy for seismic data interpolation by optimally representing the complex seismic wavefi eld and using fast and accurate iterative algorithms. The seislet transform is a sparse multiscale transform well suited for representing the seismic wavefield, as it can effectively compress seismic events. Furthermore, the Bregman iterative algorithm is an efficient algorithm for sparse representation in compressive sensing. Seismic data interpolation methods can be developed by combining seismic dynamic prediction, image transform, and compressive sensing. In this study, we link seismic data interpolation and constrained optimization. We selected the OC-seislet sparse transform to represent complex wavefields and used the Bregman iteration method to solve the hybrid norm inverse problem under the compressed sensing framework. In addition, we used an H-curve method to choose the threshold parameter in the Bregman iteration method. Thus, we achieved fast and accurate reconstruction of the seismic wavefi eld. Model and fi eld data tests demonstrate that the Bregman iteration method based on the H-curve norm in the sparse transform domain can effectively reconstruct missing complex wavefi eld data.
基金Under the auspices of Scientific Research Project Coordinatorship of Yildiz Technical University,Turkey(No.20100503KAP01)
文摘Digital elevation model (DEM) is the most popular product for three-dimensional (3D) digital representation of bare Earth surface and can be produced by many techniques with different characteristics and ground sampling distances (GSD). Space-borne opti- cal and synthetic aperture radar (SAR) imaging are two of the most preferred and modern techniques for DEM generation. Using them, global DEMs that cover almost entire Earth are produced with low cost and time saving processing. In this study, we aimed to assess the Satellite pour robservation de la Terre-5 (SPOT-5), High Resolution Stereoscopic (HRS), the Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER), and the Shuttle Radar Topography Mission (SRTM) C-band global DEMs, produced with space-borne optical and SAR imaging. For the assessment, a reference DEM derived from 1 : 1000 scaled digital photogrammetric maps was used. The study is performed in 100 km2 study area in Istanbul including various land classes such as open land, forest, built-up land, scrub and rough terrain obtained from Landsat data. The analyses were realized considering three vertical accuracy types as fundamental, supplemental, and consolidated, defined by national digital elevation program (NDEP) of USA. The results showed that, vertical accuracy of SRTM C-band DEM is better than optical models in all three accuracy types despite having the largest grid spacing. The result of SPOT-5 HRS DEM is very close by SRTM and superior in comparison with ASTER models.
文摘The CifNet network multi-well data management system is developed for 100MB or 1000MB local network environments which are used in Chinese oil industry. The kernel techniques of CifNet system include: 1, establishing a high efficient and low cost network multi-well data management architecture based on the General Logging Curve Theory and the Cif data format; 2, implementing efficient visit and transmission of multi-well data in C/S local network based on TCP/IP protocol; 3,ensuring the safety of multi-well data in store, visit and application based on Unix operating system security. By using CifNet system, the researcher in office or at home can visit curves of any borehole in any working area of any oilfield. The application foreground of CifNet system is also commented.
基金Supported by the National Nature Science Foundation of China,No.81773130the Fundamental Research Funds for the Central Universities of Central South University(the Key Projects of Postgraduate Independent Exploration and Innovation of Central South University,No.2018zzts050)the New Xiangya Talent Projects of the Third Xiangya Hospital of Central South University,No.JY201508
文摘AIM To investigate whether promoter methylation is re-sponsible for the silencing of formin 2 ( FMN2) in colorectal cancer (CRC) and to analyze the association between FMN2 methylation and CRC.METHODSWe frst identifed the expression levels and methylation levels of FMN2 in large-scale human CRC expression data-sets, including GEO and TCGA, and analyzed the relation-ship between the expression and methylation levels. Then, the methylation levels in four CpG regions adjacent to the FMN2 promoter were assessed by MethylTarget? assays in CRC cells and in paired colorectal tumor samples and adjacent nontumor tissue samples. Furthermore, we inhibited DNA methylation in CRC cells with 5-Aza-2’-deoxycytidine and assessed the expression of FMN2 by qRT-PCR. Last, the association between FMN2 methylation patterns and clinical indicators was analyzed.RESULTSA statistically significant downregulation of FMN2 ex-pression in large-scale human CRC expression datasets was found. Subsequent analysis showed that a high frequency of hypermethylation occurred in the FMN2 gene promoter in CRC tissues; operating characteristic curve analysis revealed that FMN2 gene methylation had a good capability for discriminating between CRC and nontumor tissue samples (AUC = 0.8432, P 〈 0.0001). MethylTarget? assays showed that CRC cells and tissues displayed higher methylation of these CpG regions than nontumor tissue samples. Correlation analysis showed a strong inverse correlation between methylation and FMN2 expression, and the inhibition of DNA methylation with 5-Aza significantly increased endogenous FMN2 expression. Analysis of the association between FMN2 methylation patterns and clinical indicators showed that FMN2 methylation was signifcantly associated with age, N stage, lymphovascular invasion, and pathologic tumor stage. Notably, the highest methylation of FMN2 occurred in tissues from cases of early-stage CRC, including cases with no regional lymph node metastasis (N0), cases in stages Ⅰ and Ⅱ, and cases with no lymphovascular inva-sion, but the methylation level began to decrease with tumor progression. Additionally, FMN2 promoter hyper-methylation was more common in patients 〉 60 years old and in colon cancer tissue.CONCLUSIONFMN2 promoter hypermethylation may be an important early event in CRC, most likely playing a critical role in cancer initiation, and can serve as an ideal diagnostic biomarker in elderly patients with early-stage colon cancer.
基金Funded by the National 863 Program of China (No. 2005AA113150), and the National Natural Science Foundation of China (No.40701158).
文摘A novel Hilbert-curve is introduced for parallel spatial data partitioning, with consideration of the huge-amount property of spatial information and the variable-length characteristic of vector data items. Based on the improved Hilbert curve, the algorithm can be designed to achieve almost-uniform spatial data partitioning among multiple disks in parallel spatial databases. Thus, the phenomenon of data imbalance can be significantly avoided and search and query efficiency can be enhanced.
基金Financial support for this project,provided by the National Basic Research Program of China (No.2006CB202200)the Key Project of National Natural Science Foundation of China+1 种基金the Program for Changjiang Scholars,Innovative Research Team in University of China (No.IRT0656)the Fundamental Research Funds for the Central Universities (No.2010QL04)
文摘Research into the characteristics of geothermal fields is important for the control of heat damage in mines. Based on measured geothermal data of boreholes from 200 m to 1200 m in a Jiahe Coal Mine, we demonstrate non-linear but increasing relations of both geo-temperatures and geothermal gradients with increases depth. Numerically, we fitted the relationship between geo-temperatures and depth, a first-order exponential decay curve, formulated as: T(h) = 4.975 + 23.08 exp(h/1736.1).
文摘An assistant surface was constructed on the base of boundary that being auto-matically extracted from the scattered data.The parameters of every data point corre-sponding to the assistant surface and their applied fields were calculated respectively.Inevery applied region,a surface patch was constructed by a special Hermite interpolation.The final surface can be obtained by a piecewise bicubic Hermite interpolation in the ag-gregate of applied regions of metrical data.This method avoids the triangulation problem.Numerical results indicate that it is efficient and accurate.
文摘The beam-to-column semirigid connection in a steel frame structure is represented by a zero-length rotational spring at the end of the beam element. The beam-to-column semirigid connection behavior is represented by its moment-rotation relationship. Several traditional mathematical models have been proposed to fit the moment-rotation curves from the experimental database,but they may be more reliable within certain ranges. In this paper, the intellectualized analytical model is proposed in the semirigid connections for top and seat angles with double web angles using the feed-forward back-propagation artificial neural network (BP-ANN) technique. the intellectualized analytical model from experimental results based on BP-ANN is more reliable and it is a better choice to the moment-rotation curves for beam-to-column semirigid connection. The results are found to provide effectiveness to the experimental response that is satisfactory for use in steel structural engineering design.
基金This paper was made possible by grants from the Modern Business Research Center of Zhejiang Gongshang University, Zhejiang Provincial Natural Science Foundation.
文摘This paper investigates the regional distribution and pollution of energyintensive industries in China. Through the analysis of provincial panel data collected during 1998-2008, this work estimates the drivers of pollution in 30 of China's provincial-level divisions. The paper concludes that while China's energy-intensive industries are heavily distributed in eastern and central China, the speed of development toward central and western China has, in recent years, risen continuously. Industries located in eastern China do, however, remain the primary polluters in the country. Notably, regional agglomeration of energy-intensive industries plays a positive role in energy conservation and pollution control in China. This paper also finds that patterns of pollution in China follow the environmental Kuznets curve (EKC) with strong inter-provincial discrepancies.
基金Supported by National Natural Science Foundation of China (No 20476071)
文摘The critical curves for binary systems of methane combined with nitrogen, carbon monoxide, carbon dioxide, ethane, propane, butane and water at temperatures from 125 K to 650 K and pressures from 3.5 MPa to 250 MPa were calculated by using Heilig-Franck equation of state. This equation of state contains a repulsion term and an attraction term for intermolecular interaction. With pairwise combination rules for these potentials, three adjustable parameters are needed. The results showed that the critical curves of the former six binary systems belonged to type I, and CH4+H2O system belonged to type III. The calculated data were compared with the experimental data,which yielded good results for the pressure-temperature, pressure-composition and temperature-composition behaviors of the seven systems. Moreover, the values of the adjustable parameters were obtained from the calculation of the critical curves. They can also be used for other relevant calculation.
文摘Based on the L,B and V statistics of the 106 ground feature groups or the 769 ground feature class units in the world presented in the part I of the paper,the distribution of the world ground features on the axes of L,B and V,in the planes of L-B,L-V and B-V and in the space of L-B-V was discussed.And the typical numerical characteristics of the various ground features were also summarized.
文摘On the basis of the historical statistics on power consumption, this paper anal)yes the power consumption trends in China by means of analyzing methods based on consumption proportion curve, fixed base curve, month-on-month increase curve and fixed base index curve. Special attentions are paid to the consumption trend in the first half of 2010, and policy strategies are suggested targeting the problems reflected by the consumption trend.
文摘In this paper, by using adequate stress-strain relationship, mesh elements, boundary conditions and loading conditions, the finite element ANSYS analysis on the behavior of circular tubes subjected to symmetrical cyclic bending with or without external pressure is discussed. The behavior includes the moment-curvature and ovalization-curvature relationships. In addition, the calculated ovalizations at two different sections, middle and right cross-sections, are also included. Experimental data for 6061-T6 aluminum alloy tubes subjected to cyclic bending with or without external pressure were compared with the ANSYS analysis. It has been shown that the analysis of the elastoplatic moment-curvature relationship and the symmetrical, ratcheting and increasing ovalization-curvature relationship is in good agreement with the experimental data.