目的探讨(1-3)-β-D葡聚糖联合降钙素原(procalcitonin,PCT)、CD4^(+)T淋巴细胞多指标在艾滋病患者马尔尼菲篮状菌感染早期诊断临床研究。方法回顾性选取我院2020年1月—2022年6月住院的120例艾滋病患者为研究对象。依据实验室结果,将...目的探讨(1-3)-β-D葡聚糖联合降钙素原(procalcitonin,PCT)、CD4^(+)T淋巴细胞多指标在艾滋病患者马尔尼菲篮状菌感染早期诊断临床研究。方法回顾性选取我院2020年1月—2022年6月住院的120例艾滋病患者为研究对象。依据实验室结果,将其分为马尔尼菲篮状菌感染确诊组(血或组织液培育养出马尔尼菲篮状菌),简称A组(62例),及马尔尼菲篮状菌感染临床诊断组[根据临床症状、体征、血常规及(1-3)-β-D葡聚糖、PCT、CD4^(+)T淋巴细胞多指标诊断],简称B组(58例)。检测患者(1-3)-β-D葡聚糖、PCT、CD4^(+)T淋巴细胞的表达水平,采用受试者工作特征(receiver-operating characteristic,ROC)曲线下面积(area under the curve,AUC)评估上述指标联合检测对艾滋病患者感染马尔尼菲篮状菌的诊断效能。结果A组的(1-3)-β-D葡聚糖和PCT水平均高于B组,CD4^(+)T淋巴细胞个数低于B组(P<0.05);(1-3)-β-D葡聚糖、PCT、CD4^(+)T淋巴细胞联合检测的AUC为0.933,(1-3)-β-D葡聚糖单独检测的AUC是0.812,PCT单独检测的AUC为0.883,CD4^(+)T淋巴细胞单独检测的AUC是0.810,(1-3)-β-D葡聚糖、PCT和CD4^(+)T淋巴细胞联合检测的AUC皆优于三项单独检测,表明(1-3)-β-D葡聚糖、PCT和CD4^(+)T淋巴细胞联合检测的诊断价值皆优于单一指标诊断,且联合检测的特异度、约登指数分别为92.43%和0.580,均高于三项单独检测。结论(1-3)-β-D葡聚糖联合PCT和CD4^(+)T淋巴细胞多指标对艾滋病马尔尼菲篮状菌感染具有非常高的临床诊断价值,能够帮助医生分析出高危风险患者,及时制定治疗方案,同时也承担预后效果的判断依据,对治疗艾滋病马尔尼菲篮状菌感染具有非常重要的研究价值。展开更多
The synthesis of new 4-imino-4H-chromeno[2,3-d]pyrimidin-3(5H)-amine in four steps including one step under microwave dielectric heating is reported. The structural identity of the synthesized compounds was establishe...The synthesis of new 4-imino-4H-chromeno[2,3-d]pyrimidin-3(5H)-amine in four steps including one step under microwave dielectric heating is reported. The structural identity of the synthesized compounds was established according to their spectroscopic analysis, such as FT-IR, NMR and mass spectroscopy. These new compounds were tested for their antiproliferative activities on seven representative human tumoral cell lines (Huh7 D12, Caco2, MDA-MB231, MDA-MB468, HCT116, PC3 and MCF7) and also on fibroblasts. Among them, only the compounds 6c showed micromolar cytotoxic activity on tumor cell lines (1.8 50 50 > 25 μM). Finally, in silico ADMET studies ware performed to investigate the possibility of using of the identified compound 6c as potential anti-tumor compound.展开更多
A novel algorithm of 3-D surface image registration is proposed. It makes use of the array information of 3-D points and takes vector/vertex-like features as the basis of the matching. That array information of 3-D po...A novel algorithm of 3-D surface image registration is proposed. It makes use of the array information of 3-D points and takes vector/vertex-like features as the basis of the matching. That array information of 3-D points can be easily obtained when capturing original 3-D images. The iterative least-mean-squared (LMS) algorithm is applied to optimizing adaptively the transformation matrix parameters. These can effectively improve the registration performance and hurry up the matching process. Experimental results show that it can reach a good subjective impression on aligned 3-D images. Although the algorithm focuses primarily on the human head model, it can also be used for other objects with small modifications.展开更多
Accurate 3-dimensional(3-D)reconstruction technology for nondestructive testing based on digital radiography(DR)is of great importance for alleviating the drawbacks of the existing computed tomography(CT)-based method...Accurate 3-dimensional(3-D)reconstruction technology for nondestructive testing based on digital radiography(DR)is of great importance for alleviating the drawbacks of the existing computed tomography(CT)-based method.The commonly used Monte Carlo simulation method ensures well-performing imaging results for DR.However,for 3-D reconstruction,it is limited by its high time consumption.To solve this problem,this study proposes a parallel computing method to accelerate Monte Carlo simulation for projection images with a parallel interface and a specific DR application.The images are utilized for 3-D reconstruction of the test model.We verify the accuracy of parallel computing for DR and evaluate the performance of two parallel computing modes-multithreaded applications(G4-MT)and message-passing interfaces(G4-MPI)-by assessing parallel speedup and efficiency.This study explores the scalability of the hybrid G4-MPI and G4-MT modes.The results show that the two parallel computing modes can significantly reduce the Monte Carlo simulation time because the parallel speedup increment of Monte Carlo simulations can be considered linear growth,and the parallel efficiency is maintained at a high level.The hybrid mode has strong scalability,as the overall run time of the 180 simulations using 320 threads is 15.35 h with 10 billion particles emitted,and the parallel speedup can be up to 151.36.The 3-D reconstruction of the model is achieved based on the filtered back projection(FBP)algorithm using 180 projection images obtained with the hybrid G4-MPI and G4-MT.The quality of the reconstructed sliced images is satisfactory because the images can reflect the internal structure of the test model.This method is applied to a complex model,and the quality of the reconstructed images is evaluated.展开更多
3-dimension(3-D)printing technology is growing strongly with many applications,one of which is the garment industry.The application of human body models to the garment industry is necessary to respond to the increasin...3-dimension(3-D)printing technology is growing strongly with many applications,one of which is the garment industry.The application of human body models to the garment industry is necessary to respond to the increasing personalization demand and still guarantee aesthetics.This paper proposes amethod to construct 3-D human models by applying deep learning.We calculate the location of the main slices of the human body,including the neck,chest,belly,buttocks,and the rings of the extremities,using pre-existing information.Then,on the positioning frame,we find the key points(fixed and unaltered)of these key slices and update these points tomatch the current parameters.To add points to a star slice,we use a deep learning model tomimic the form of the human body at that slice position.We use interpolation to produce sub-slices of different body sections based on the main slices to create complete body parts morphologically.We combine all slices to construct a full 3-D representation of the human body.展开更多
This paper concerns the sonic-supersonic structures of the transonic crossflow generated by the steady supersonic flow past an infinite cone of arbitrary cross section.Under the conical assumption,the three-dimensiona...This paper concerns the sonic-supersonic structures of the transonic crossflow generated by the steady supersonic flow past an infinite cone of arbitrary cross section.Under the conical assumption,the three-dimensional(3-D)steady Euler equations can be projected onto the unit sphere and the state of fluid can be characterized by the polar and azimuthal angles.Given a segment smooth curve as a conical-sonic line in the polar-azimuthal angle plane,we construct a classical conical-supersonic solution near the curve under some reasonable assumptions.To overcome the difficulty caused by the parabolic degeneracy,we apply the characteristic decomposition technique to transform the Euler equations into a new degenerate hyperbolic system in a partial hodograph plane.The singular terms are isolated from the highly nonlinear complicated system and then can be handled successfully.We establish a smooth local solution to the new system in a suitable weighted metric space and then express the solution in terms of the original variables.展开更多
Feature extraction is the most critical step in classification of multispectral image.The classification accuracy is mainly influenced by the feature sets that are selected to classify the image.In the past,handcrafte...Feature extraction is the most critical step in classification of multispectral image.The classification accuracy is mainly influenced by the feature sets that are selected to classify the image.In the past,handcrafted feature sets are used which are not adaptive for different image domains.To overcome this,an evolu-tionary learning method is developed to automatically learn the spatial-spectral features for classification.A modified Firefly Algorithm(FA)which achieves maximum classification accuracy with reduced size of feature set is proposed to gain the interest of feature selection for this purpose.For extracting the most effi-cient features from the data set,we have used 3-D discrete wavelet transform which decompose the multispectral image in all three dimensions.For selecting spatial and spectral features we have studied three different approaches namely overlapping window(OW-3DFS),non-overlapping window(NW-3DFS)adaptive window cube(AW-3DFS)and Pixel based technique.Fivefold Multiclass Support Vector Machine(MSVM)is used for classification purpose.Experiments con-ducted on Madurai LISS IV multispectral image exploited that the adaptive win-dow approach is used to increase the classification accuracy.展开更多
A 3-D digital core describes the pore space microstructure of rocks. An X-ray micro CT scan is the most accurate and direct but costly method to obtain a 3-D digital core. In this study, we propose a hybrid method whi...A 3-D digital core describes the pore space microstructure of rocks. An X-ray micro CT scan is the most accurate and direct but costly method to obtain a 3-D digital core. In this study, we propose a hybrid method which combines sedimentation simulation and simulated annealing (SA) method to generate 3-D digital cores based on 2-D images of rocks. The method starts with the sedimentation simulation to build a 3-D digital core, which is the initial configuration for the SA method. We update the initial digital core using the SA method to match the auto-correlation function of the 2-D rock image and eventually build the final 3-D digital core. Compared with the typical SA method, the hybrid method has significantly reduced the computation time. Local porosity theory is applied to quantitatively compare the reconstructed 3-D digital cores with the X-ray micro CT 3-D images. The results indicate that the 3-D digital cores reconstructed by the hybrid method have homogeneity and geometric connectivity similar to those of the X-ray micro CT image. The formation factors and permeabilities of the reconstructed 3-D digital cores are estimated using the finite element method (FEM) and lattice Boltzmann method (LBM), respectively. The simulated results are in good agreement with the experimental measurements. Comparison of the simulation results suggests that the digital cores reconstructed by the hybrid method more closely reflect the true transport properties than the typical SA method alone.展开更多
3-D geological modeling plays an increasingly important role in Petroleum Geology, Mining Geology and Engineering Geology. The complexity of geological conditions requires different modeling methods in different situa...3-D geological modeling plays an increasingly important role in Petroleum Geology, Mining Geology and Engineering Geology. The complexity of geological conditions requires different modeling methods in different situations. This paper summarizes the general concept of geological modeling; compares the characteristics of borehole-based modeling, cross-section based modeling and multi- source interactive modeling; analyses key techniques in 3-D geological modeling; and highlights the main difficulties and directions of future studies.展开更多
Western Yunnan is a region with intensive tectonic activity and serious earthquake risk. It is of significant importance to study three dimensional crustal structure of this region to understand the tectonic setting a...Western Yunnan is a region with intensive tectonic activity and serious earthquake risk. It is of significant importance to study three dimensional crustal structure of this region to understand the tectonic setting and disaster mechanism. Densification and digitalization of seismic networks in this region provides an opportunity to study the velocity structure with bulletin data. In this study, we collect P-wave data of 10 403 regional earthquakes recorded by 79 seismic stations from January 2008 to December 2010. In addition to first arrivals data (Pg with epieentral distance less than 200 km and Pn), the Pg (or P) data with epicentral distance more than 200 km are also considered as later direct arrivals in the tomographic inversion. We also compare the quantity and the quality of the seismic data before 2010 and after 2010. The test results show that adding the follow-up Pg phase can effectively improve the inversion ability of crustal imaging, and quantity and the data quality are significantly improved since 2010. The tomographie results show that: (1) The Honghe fault zone, which is the major fault systems in this region, may cut through the entire crust, and the velocity contrasts between two sides at lower crust beneath the Honghe fault are estimated at higher than 10%, while the velocity difference below Nujiang fault zone extends only in the upper crust; (2) Most of the earthquakes in the region occurred at the interface of high-velocity media and low-velocity media, i.e., the areas with high velocity gradient, which has been validated in other areas.展开更多
Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is deter...Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is determined, incorporating with previous deep geophysical data. In the upper crust, a positive anomaly velocity zone exists in the Sichuan basin, whereas a negative anomaly velocity zone exists in the western Sichuan plateau. The boundary between the positive and negative anomaly zones is the Longmenshan fault zone. The images of lower crust and upper mantle in the Longmenshan fault, Xianshuihe fault, Honghe fault and others show the characteristic of tectonic boundary, indicating that the faults likely penetrate the Moho discontinuity. The negative velocity anomalies at the depth of 50 km in the Tengchong volcanic area and the Panxi tectonic zone appear to be associated with the temperature and composition variations in the upper mantle. The overall features of the crustal and the upper mantle structures in the SichuanYunnan region are the lower average velocity in both crust and uppermost mantle, the large crustal thickness variations, and the existence of high conductivity layer in the crust or/and upper mantle, and higher geothermal value. All these features are closely related to the collision between the India and the Asia plates. The crustal velocity in the SichuanYunnan rhombic block generally shows normal value or positive anomaly, while the negative anomaly exists in the area along the large strike-slip faults as the block boundary. It is conducive to the crustal block side-pressing out along the faults. In the major seismic zones, the seismicity is relative to the negative anomaly velocity. Most strong earthquakes occurred in the upper-mid crust with positive anomaly or normal velocity, where the negative anomaly zone generally exists below.展开更多
Ethnic mountain settlements are living heritage of varied vernacular cultures.The preservation of both the built form and the intangible socio-cultural associations with them are global concern in process of urbanizat...Ethnic mountain settlements are living heritage of varied vernacular cultures.The preservation of both the built form and the intangible socio-cultural associations with them are global concern in process of urbanization,and in the notion of sustainable development.However,there is a lack of multi-dimensional and cross-cultural quantitative research in settlement morphology,making it difficult to guide practice effectively.Therefore,this study focuses on exploring an automatic or semi-automatic quantification and classification method for the morphological identity of ethnic mountain settlements.We introduce and combine 3-D morphological indicators with existing 2-D indicators to build and test three different sets of indication systems for semi-automatic classification for the settlements’ethnic attribute basing on spatial morphology.Taking the Miao,Dong,and Tunpu(Han)ethnic settlements in Guizhou province,southwest China as research samples,we applied factor analysis and hierarchical clustering methods to compare the classification accuracy under the three systems using data from topographic map,field investigation map,satellite imageries,and ethnography or local chronicle.The results showed that,the 3-D indication system has succeeded in semi-automatic quantification and classification of settlement morphology and ethnic identity by greatly increasing the classification accuracy to 96.30%,which is a huge improvement compared with the basic 2-D indication system(42.59%)and the advanced 2-D indication system(61.11%).The settlement samples are further divided into two sub-types with significant morphological differences in each major ethnic category under the 3-D indication system.We then discussed the potential improvement and future large-scale application of this method with the help of machine learning and other smart techniques.We hope to provide a comprehensive quantitative perspective and a more scientific reference for the future preservation and sustainable development of the massive and diverse vernacular heritages across the world.展开更多
Basing on the analysis of the traits of the roll forging process, a system-model of computer simulation has been established. Three-dimensional rigid-plastic FEM has been used for the simulation of the deformation pro...Basing on the analysis of the traits of the roll forging process, a system-model of computer simulation has been established. Three-dimensional rigid-plastic FEM has been used for the simulation of the deformation process in the oval and round pass rolling, including the entering, rolling, and separating stages. The analysis was conducted using the Deform-3D ver.5.0 code. The important information concerned with the deformation area characteristic, material flow, and velocity field has been presented. Otherwise, the location of the neutral plane in the deformation area was shown clearly.展开更多
3-D rigid visco-plastic finite element method (FEM) is used in the analysisof metal forming processes, including strip and plate rolling, shape rolling, slab edging, specialstrip rolling. The shifted incomplete Choles...3-D rigid visco-plastic finite element method (FEM) is used in the analysisof metal forming processes, including strip and plate rolling, shape rolling, slab edging, specialstrip rolling. The shifted incomplete Cholesky decomposition of the stiffness matrix with thesolution of the equations for velocity increment by the conjugate gradient method is combined. Thistechnique, termed the shifted ICCG method, is then employed to solve the slab edging problem. Theperformance of this algorithm in terms of the number of iterations, friction variation, shiftedparameter psi and the results of simulation for processing parameters are analysed. Numerical testsand application of this technique verify the efficiency and stability of the shifted ICCG method inthe analysis of slab edging.展开更多
文摘目的探讨(1-3)-β-D葡聚糖联合降钙素原(procalcitonin,PCT)、CD4^(+)T淋巴细胞多指标在艾滋病患者马尔尼菲篮状菌感染早期诊断临床研究。方法回顾性选取我院2020年1月—2022年6月住院的120例艾滋病患者为研究对象。依据实验室结果,将其分为马尔尼菲篮状菌感染确诊组(血或组织液培育养出马尔尼菲篮状菌),简称A组(62例),及马尔尼菲篮状菌感染临床诊断组[根据临床症状、体征、血常规及(1-3)-β-D葡聚糖、PCT、CD4^(+)T淋巴细胞多指标诊断],简称B组(58例)。检测患者(1-3)-β-D葡聚糖、PCT、CD4^(+)T淋巴细胞的表达水平,采用受试者工作特征(receiver-operating characteristic,ROC)曲线下面积(area under the curve,AUC)评估上述指标联合检测对艾滋病患者感染马尔尼菲篮状菌的诊断效能。结果A组的(1-3)-β-D葡聚糖和PCT水平均高于B组,CD4^(+)T淋巴细胞个数低于B组(P<0.05);(1-3)-β-D葡聚糖、PCT、CD4^(+)T淋巴细胞联合检测的AUC为0.933,(1-3)-β-D葡聚糖单独检测的AUC是0.812,PCT单独检测的AUC为0.883,CD4^(+)T淋巴细胞单独检测的AUC是0.810,(1-3)-β-D葡聚糖、PCT和CD4^(+)T淋巴细胞联合检测的AUC皆优于三项单独检测,表明(1-3)-β-D葡聚糖、PCT和CD4^(+)T淋巴细胞联合检测的诊断价值皆优于单一指标诊断,且联合检测的特异度、约登指数分别为92.43%和0.580,均高于三项单独检测。结论(1-3)-β-D葡聚糖联合PCT和CD4^(+)T淋巴细胞多指标对艾滋病马尔尼菲篮状菌感染具有非常高的临床诊断价值,能够帮助医生分析出高危风险患者,及时制定治疗方案,同时也承担预后效果的判断依据,对治疗艾滋病马尔尼菲篮状菌感染具有非常重要的研究价值。
文摘The synthesis of new 4-imino-4H-chromeno[2,3-d]pyrimidin-3(5H)-amine in four steps including one step under microwave dielectric heating is reported. The structural identity of the synthesized compounds was established according to their spectroscopic analysis, such as FT-IR, NMR and mass spectroscopy. These new compounds were tested for their antiproliferative activities on seven representative human tumoral cell lines (Huh7 D12, Caco2, MDA-MB231, MDA-MB468, HCT116, PC3 and MCF7) and also on fibroblasts. Among them, only the compounds 6c showed micromolar cytotoxic activity on tumor cell lines (1.8 50 50 > 25 μM). Finally, in silico ADMET studies ware performed to investigate the possibility of using of the identified compound 6c as potential anti-tumor compound.
文摘A novel algorithm of 3-D surface image registration is proposed. It makes use of the array information of 3-D points and takes vector/vertex-like features as the basis of the matching. That array information of 3-D points can be easily obtained when capturing original 3-D images. The iterative least-mean-squared (LMS) algorithm is applied to optimizing adaptively the transformation matrix parameters. These can effectively improve the registration performance and hurry up the matching process. Experimental results show that it can reach a good subjective impression on aligned 3-D images. Although the algorithm focuses primarily on the human head model, it can also be used for other objects with small modifications.
基金the China Natural Science Fund(No.52171253)the Natural Science Foundation of Sichuan(No.2022NSFSCO949).
文摘Accurate 3-dimensional(3-D)reconstruction technology for nondestructive testing based on digital radiography(DR)is of great importance for alleviating the drawbacks of the existing computed tomography(CT)-based method.The commonly used Monte Carlo simulation method ensures well-performing imaging results for DR.However,for 3-D reconstruction,it is limited by its high time consumption.To solve this problem,this study proposes a parallel computing method to accelerate Monte Carlo simulation for projection images with a parallel interface and a specific DR application.The images are utilized for 3-D reconstruction of the test model.We verify the accuracy of parallel computing for DR and evaluate the performance of two parallel computing modes-multithreaded applications(G4-MT)and message-passing interfaces(G4-MPI)-by assessing parallel speedup and efficiency.This study explores the scalability of the hybrid G4-MPI and G4-MT modes.The results show that the two parallel computing modes can significantly reduce the Monte Carlo simulation time because the parallel speedup increment of Monte Carlo simulations can be considered linear growth,and the parallel efficiency is maintained at a high level.The hybrid mode has strong scalability,as the overall run time of the 180 simulations using 320 threads is 15.35 h with 10 billion particles emitted,and the parallel speedup can be up to 151.36.The 3-D reconstruction of the model is achieved based on the filtered back projection(FBP)algorithm using 180 projection images obtained with the hybrid G4-MPI and G4-MT.The quality of the reconstructed sliced images is satisfactory because the images can reflect the internal structure of the test model.This method is applied to a complex model,and the quality of the reconstructed images is evaluated.
基金Funding for this study from Sai Gon University(Grant No.CSA2021–08).
文摘3-dimension(3-D)printing technology is growing strongly with many applications,one of which is the garment industry.The application of human body models to the garment industry is necessary to respond to the increasing personalization demand and still guarantee aesthetics.This paper proposes amethod to construct 3-D human models by applying deep learning.We calculate the location of the main slices of the human body,including the neck,chest,belly,buttocks,and the rings of the extremities,using pre-existing information.Then,on the positioning frame,we find the key points(fixed and unaltered)of these key slices and update these points tomatch the current parameters.To add points to a star slice,we use a deep learning model tomimic the form of the human body at that slice position.We use interpolation to produce sub-slices of different body sections based on the main slices to create complete body parts morphologically.We combine all slices to construct a full 3-D representation of the human body.
基金the two referees for very helpful comments and suggestions to improve the quality of the paper.This work was partially supported by the Natural Science Foundation of Zhejiang province of China(LY21A010017)the National Natural Science Foundation of China(12071106,12171130).
文摘This paper concerns the sonic-supersonic structures of the transonic crossflow generated by the steady supersonic flow past an infinite cone of arbitrary cross section.Under the conical assumption,the three-dimensional(3-D)steady Euler equations can be projected onto the unit sphere and the state of fluid can be characterized by the polar and azimuthal angles.Given a segment smooth curve as a conical-sonic line in the polar-azimuthal angle plane,we construct a classical conical-supersonic solution near the curve under some reasonable assumptions.To overcome the difficulty caused by the parabolic degeneracy,we apply the characteristic decomposition technique to transform the Euler equations into a new degenerate hyperbolic system in a partial hodograph plane.The singular terms are isolated from the highly nonlinear complicated system and then can be handled successfully.We establish a smooth local solution to the new system in a suitable weighted metric space and then express the solution in terms of the original variables.
文摘Feature extraction is the most critical step in classification of multispectral image.The classification accuracy is mainly influenced by the feature sets that are selected to classify the image.In the past,handcrafted feature sets are used which are not adaptive for different image domains.To overcome this,an evolu-tionary learning method is developed to automatically learn the spatial-spectral features for classification.A modified Firefly Algorithm(FA)which achieves maximum classification accuracy with reduced size of feature set is proposed to gain the interest of feature selection for this purpose.For extracting the most effi-cient features from the data set,we have used 3-D discrete wavelet transform which decompose the multispectral image in all three dimensions.For selecting spatial and spectral features we have studied three different approaches namely overlapping window(OW-3DFS),non-overlapping window(NW-3DFS)adaptive window cube(AW-3DFS)and Pixel based technique.Fivefold Multiclass Support Vector Machine(MSVM)is used for classification purpose.Experiments con-ducted on Madurai LISS IV multispectral image exploited that the adaptive win-dow approach is used to increase the classification accuracy.
基金sponsored by NSFC(Grant No.40574030)CNPC Research Project(Grant No.06A30102)
文摘A 3-D digital core describes the pore space microstructure of rocks. An X-ray micro CT scan is the most accurate and direct but costly method to obtain a 3-D digital core. In this study, we propose a hybrid method which combines sedimentation simulation and simulated annealing (SA) method to generate 3-D digital cores based on 2-D images of rocks. The method starts with the sedimentation simulation to build a 3-D digital core, which is the initial configuration for the SA method. We update the initial digital core using the SA method to match the auto-correlation function of the 2-D rock image and eventually build the final 3-D digital core. Compared with the typical SA method, the hybrid method has significantly reduced the computation time. Local porosity theory is applied to quantitatively compare the reconstructed 3-D digital cores with the X-ray micro CT 3-D images. The results indicate that the 3-D digital cores reconstructed by the hybrid method have homogeneity and geometric connectivity similar to those of the X-ray micro CT image. The formation factors and permeabilities of the reconstructed 3-D digital cores are estimated using the finite element method (FEM) and lattice Boltzmann method (LBM), respectively. The simulated results are in good agreement with the experimental measurements. Comparison of the simulation results suggests that the digital cores reconstructed by the hybrid method more closely reflect the true transport properties than the typical SA method alone.
文摘3-D geological modeling plays an increasingly important role in Petroleum Geology, Mining Geology and Engineering Geology. The complexity of geological conditions requires different modeling methods in different situations. This paper summarizes the general concept of geological modeling; compares the characteristics of borehole-based modeling, cross-section based modeling and multi- source interactive modeling; analyses key techniques in 3-D geological modeling; and highlights the main difficulties and directions of future studies.
基金supported by China National Special Fund for Earthquake Scientific Research in Public Interest (Grant 201208004)National Natural Science Foundation of China (grant 41174040)Scientific Research Institutes’ Basic Research and Development Operations Special Fund of Institute of Geophysics,China Earthquake Administration (grant DQJB10A01)
文摘Western Yunnan is a region with intensive tectonic activity and serious earthquake risk. It is of significant importance to study three dimensional crustal structure of this region to understand the tectonic setting and disaster mechanism. Densification and digitalization of seismic networks in this region provides an opportunity to study the velocity structure with bulletin data. In this study, we collect P-wave data of 10 403 regional earthquakes recorded by 79 seismic stations from January 2008 to December 2010. In addition to first arrivals data (Pg with epieentral distance less than 200 km and Pn), the Pg (or P) data with epicentral distance more than 200 km are also considered as later direct arrivals in the tomographic inversion. We also compare the quantity and the quality of the seismic data before 2010 and after 2010. The test results show that adding the follow-up Pg phase can effectively improve the inversion ability of crustal imaging, and quantity and the data quality are significantly improved since 2010. The tomographie results show that: (1) The Honghe fault zone, which is the major fault systems in this region, may cut through the entire crust, and the velocity contrasts between two sides at lower crust beneath the Honghe fault are estimated at higher than 10%, while the velocity difference below Nujiang fault zone extends only in the upper crust; (2) Most of the earthquakes in the region occurred at the interface of high-velocity media and low-velocity media, i.e., the areas with high velocity gradient, which has been validated in other areas.
基金Foundation item: National Scientific and Technological Development Program (95-973-02-02) the Climb Program (95-S-05-01) of National Scientific and Technological Ministry of China and the State Natural Sciences Foundation of China (49874021).
文摘Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is determined, incorporating with previous deep geophysical data. In the upper crust, a positive anomaly velocity zone exists in the Sichuan basin, whereas a negative anomaly velocity zone exists in the western Sichuan plateau. The boundary between the positive and negative anomaly zones is the Longmenshan fault zone. The images of lower crust and upper mantle in the Longmenshan fault, Xianshuihe fault, Honghe fault and others show the characteristic of tectonic boundary, indicating that the faults likely penetrate the Moho discontinuity. The negative velocity anomalies at the depth of 50 km in the Tengchong volcanic area and the Panxi tectonic zone appear to be associated with the temperature and composition variations in the upper mantle. The overall features of the crustal and the upper mantle structures in the SichuanYunnan region are the lower average velocity in both crust and uppermost mantle, the large crustal thickness variations, and the existence of high conductivity layer in the crust or/and upper mantle, and higher geothermal value. All these features are closely related to the collision between the India and the Asia plates. The crustal velocity in the SichuanYunnan rhombic block generally shows normal value or positive anomaly, while the negative anomaly exists in the area along the large strike-slip faults as the block boundary. It is conducive to the crustal block side-pressing out along the faults. In the major seismic zones, the seismicity is relative to the negative anomaly velocity. Most strong earthquakes occurred in the upper-mid crust with positive anomaly or normal velocity, where the negative anomaly zone generally exists below.
基金supported by the National Key R&D Program of China(No.2018YFD1100303)。
文摘Ethnic mountain settlements are living heritage of varied vernacular cultures.The preservation of both the built form and the intangible socio-cultural associations with them are global concern in process of urbanization,and in the notion of sustainable development.However,there is a lack of multi-dimensional and cross-cultural quantitative research in settlement morphology,making it difficult to guide practice effectively.Therefore,this study focuses on exploring an automatic or semi-automatic quantification and classification method for the morphological identity of ethnic mountain settlements.We introduce and combine 3-D morphological indicators with existing 2-D indicators to build and test three different sets of indication systems for semi-automatic classification for the settlements’ethnic attribute basing on spatial morphology.Taking the Miao,Dong,and Tunpu(Han)ethnic settlements in Guizhou province,southwest China as research samples,we applied factor analysis and hierarchical clustering methods to compare the classification accuracy under the three systems using data from topographic map,field investigation map,satellite imageries,and ethnography or local chronicle.The results showed that,the 3-D indication system has succeeded in semi-automatic quantification and classification of settlement morphology and ethnic identity by greatly increasing the classification accuracy to 96.30%,which is a huge improvement compared with the basic 2-D indication system(42.59%)and the advanced 2-D indication system(61.11%).The settlement samples are further divided into two sub-types with significant morphological differences in each major ethnic category under the 3-D indication system.We then discussed the potential improvement and future large-scale application of this method with the help of machine learning and other smart techniques.We hope to provide a comprehensive quantitative perspective and a more scientific reference for the future preservation and sustainable development of the massive and diverse vernacular heritages across the world.
基金supported by the National Natural Science Foundation of China(No.50675014).
文摘Basing on the analysis of the traits of the roll forging process, a system-model of computer simulation has been established. Three-dimensional rigid-plastic FEM has been used for the simulation of the deformation process in the oval and round pass rolling, including the entering, rolling, and separating stages. The analysis was conducted using the Deform-3D ver.5.0 code. The important information concerned with the deformation area characteristic, material flow, and velocity field has been presented. Otherwise, the location of the neutral plane in the deformation area was shown clearly.
基金supported by Huo Yingdong Young Teachers Foundation,Ministry of State Education of ChinaNational Natural Science Foundation of China(No.59904003).
文摘3-D rigid visco-plastic finite element method (FEM) is used in the analysisof metal forming processes, including strip and plate rolling, shape rolling, slab edging, specialstrip rolling. The shifted incomplete Cholesky decomposition of the stiffness matrix with thesolution of the equations for velocity increment by the conjugate gradient method is combined. Thistechnique, termed the shifted ICCG method, is then employed to solve the slab edging problem. Theperformance of this algorithm in terms of the number of iterations, friction variation, shiftedparameter psi and the results of simulation for processing parameters are analysed. Numerical testsand application of this technique verify the efficiency and stability of the shifted ICCG method inthe analysis of slab edging.