By use of a three-dimensional compressible non-hydrostatic convective cloud model with detailed microphysics featuring spectral bins of cloud condensation nuclei （CCN）, liquid droplets, ice crystals, snow and graupe...By use of a three-dimensional compressible non-hydrostatic convective cloud model with detailed microphysics featuring spectral bins of cloud condensation nuclei （CCN）, liquid droplets, ice crystals, snow and graupel particles, the spatial and temporal distributions of hydrometeors in a supercell observed by the （Severe Thunderstorm Electrification and Precipitation Study） STEPS triple-radar network are simulated and analyzed. The bin model is also employed to study the effect of CCN concentration on the evolution characteristics of the supercell. It is found that the CCN concentration not only affects the concentration and spectral distribution of water droplets, but also influences the characteristics of ice crystals and graupel particles. With a larger number of CCN, more water droplets and ice crystals are produced and the growth of graupel is restrained. With a small quantity of CCN the production of large size water droplets are promoted by initially small concentrations of water droplets and ice crystals, leading to earlier formation of small size graupel and restraining the recycling growth of graupel, and thus inhibiting the formation of large size graupel （or small size hail）. It can be concluded that both the macroscopic airflow and microphysical processes influence the formation and growth of large size graupel （or small size hail）. In regions with heavy pollution, a high concentration of CCN may restrain the formation of graupel and hail, and in extremely clean regions, excessively low concentrations of CCN may also limit the formation of large size graupel （hail）.展开更多
The testing on the bearing strength of single-shear bolt jointed composite laminates structure is done.And the effect of the fixture on the testing results is analyzed. Then a macro-micro multi-scale analytical model ...The testing on the bearing strength of single-shear bolt jointed composite laminates structure is done.And the effect of the fixture on the testing results is analyzed. Then a macro-micro multi-scale analytical model combined with the improved"Generalized Method of Cells( GMC) "is developed,which is used to predict the macro bearing strength and to characterize the micro constitute material failure of the bolt jointed composite laminates structure. Both the contact conditions at the bolt/hole boundary and the contact conditions at the specimen/fixture boundary,progressive damage,and the material properties degradation are all taken account into the analytical model. Thus,the numerical simulation results agree well with the experimental results.Finally,the effect of the fixture on the testing results is characterized. The results show that the incomplete contaction between the fixture and the specimen or the lack of the lateral constraint on the specimen will affect the limited bearing strength and the offset bearing strength of the bolt jointed composite laminates structure. In addition,the lower support rigid of the fixture will affect the rigid of the bolt jointed composite laminates structure.展开更多
The macro and micro cloud physics structures and their evolution with time are the core of describing cloud fields in essence.They are necessary atmospheric environment not only in aviation and spaceflight activities ...The macro and micro cloud physics structures and their evolution with time are the core of describing cloud fields in essence.They are necessary atmospheric environment not only in aviation and spaceflight activities but also for atmos- pheric radiation transfer and acid rain formation research.Unfortunately it is difficult to obtain an entire environmental cloud field by using observation methods directly.Thus,by use of computation physics method to build a cloud-system model may be an indispensable way for this topic.This paper presented a cloud-system model for this goal,and simu- lated a real case.The results of computation showed that the macro structure of the cloud field was better consistent with real observation,and the micro structure was fairly reasonable.The output of model could provide all the information about the cloud field:(1)size-distribution spectrum of hydrometeor particles (point),(2)vertical profile (line),(3)hori- zontal or vertical section of macro and micro parameters (surface),and (4)cloud cover,pattern of cloud and configura- tion of cloud,etc.(body).展开更多
Ligaments are densely connective soft tissues capable of maintaining stability and function of knee joint.As an important factor,the constitutive relation of ligament would affect its biomechanics and further play an ...Ligaments are densely connective soft tissues capable of maintaining stability and function of knee joint.As an important factor,the constitutive relation of ligament would affect its biomechanics and further play an essential role in the research on ligament injury,healing and treatment.The objective of this paper is to provide an overview of the current research on ligament constitutive relations on the macro,meso,and micro levels as well as the anatomy and histological structure of ligament.Some studies of biomechanical behaviors during ligament injury and healing periods have also been investigated.Based on the research on ligament constitutive relation in the past three decades,a discussion of some research perspectives is also presented,such as a validated accurate measuring method of in situ strain in ligament,a new constitutive relation involving the distribution of ultra-structural properties,and a rational estimation of ligament injury and healing process by the change of its ultra-structural or histological characteristics.展开更多
Abstract:This article endeavors to investigate the difference and similarities between English abstracts in the field of petroleum written by native academicians and Chinese scholars by means of comparison.It is resea...Abstract:This article endeavors to investigate the difference and similarities between English abstracts in the field of petroleum written by native academicians and Chinese scholars by means of comparison.It is researched from two aspects:macro-genre structure and micro-linguistic features based on corpus study in order to find out the reason why some articles are good enough to be employed in the international research organization such as EI or SCI,and propose constructive instructions for informative abstract writing.展开更多
目的探究3D打印多孔结构陶瓷材料外科植入物孔隙结构的宏微观特征分析及评价方法。方法基于微米X射线CT(Micro-CT)扫描获取的多孔样品图像数据,利用VG Studio MAX 3.0软件及Mimics 16.0软件的多孔结构分析功能,对多孔结构的宏观结构特...目的探究3D打印多孔结构陶瓷材料外科植入物孔隙结构的宏微观特征分析及评价方法。方法基于微米X射线CT(Micro-CT)扫描获取的多孔样品图像数据,利用VG Studio MAX 3.0软件及Mimics 16.0软件的多孔结构分析功能,对多孔结构的宏观结构特征包括总孔隙率、宏孔孔径、内连接、开/闭孔率等进行测量和分析;同时,采用扫描电子显微镜对样品表面微观多孔形貌进行特征分析和评价。结果基于Micro-CT和SEM扫描及影像学分析实现了针对3D打印多孔结构陶瓷样件的孔隙结构的宏微观特征表征和统计分析,并验证了其可行性和准确性,形成了一套面向3D打印多孔结构陶瓷材料外科植入物形貌宏微结构尺寸特征的有效的测量和评价方法。结论本文提出的基于Micro-CT和SEM扫描成像进行3D打印多孔结构陶瓷样件的孔隙结构的宏微观特征表征和分析的统计方法,有利于实现多孔结构宏微观特征的相关测试内容和试验过程的规范统一,确保测试过程方法有据可依,结果评价准确有效,有利于提升产品的加工精度,便于不同企业同种工艺制造的多孔结构特征参数之间等同比较,为医疗器械行业多孔结构宏微观特征的数据积累奠定基础,有利于提高与人体生命安全息息相关的外科植入物产品的研发和制造水平。展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.40537034, 40805057)Jiangsu Province Qinglan Project"cloud fog precipitation and aerosol research group", Foun-dation of Key Laboratory for Cloud Physics and Weather Modification of CMA (Grant No. 2009Z0036)Foun-dation of Nanjing University of Information Science &Technology
文摘By use of a three-dimensional compressible non-hydrostatic convective cloud model with detailed microphysics featuring spectral bins of cloud condensation nuclei （CCN）, liquid droplets, ice crystals, snow and graupel particles, the spatial and temporal distributions of hydrometeors in a supercell observed by the （Severe Thunderstorm Electrification and Precipitation Study） STEPS triple-radar network are simulated and analyzed. The bin model is also employed to study the effect of CCN concentration on the evolution characteristics of the supercell. It is found that the CCN concentration not only affects the concentration and spectral distribution of water droplets, but also influences the characteristics of ice crystals and graupel particles. With a larger number of CCN, more water droplets and ice crystals are produced and the growth of graupel is restrained. With a small quantity of CCN the production of large size water droplets are promoted by initially small concentrations of water droplets and ice crystals, leading to earlier formation of small size graupel and restraining the recycling growth of graupel, and thus inhibiting the formation of large size graupel （or small size hail）. It can be concluded that both the macroscopic airflow and microphysical processes influence the formation and growth of large size graupel （or small size hail）. In regions with heavy pollution, a high concentration of CCN may restrain the formation of graupel and hail, and in extremely clean regions, excessively low concentrations of CCN may also limit the formation of large size graupel （hail）.
基金Sponsored by the National Natural Science Foundation of China(Grant No.11272105)the Heilongjiang Province Science Foundation for Youths(Grant No.QC2015003)the Harbin Science and Technology Bureau Young Talent Reserve Project(Grant No.RC2016QN001011,RC2016QN017023)
文摘The testing on the bearing strength of single-shear bolt jointed composite laminates structure is done.And the effect of the fixture on the testing results is analyzed. Then a macro-micro multi-scale analytical model combined with the improved"Generalized Method of Cells( GMC) "is developed,which is used to predict the macro bearing strength and to characterize the micro constitute material failure of the bolt jointed composite laminates structure. Both the contact conditions at the bolt/hole boundary and the contact conditions at the specimen/fixture boundary,progressive damage,and the material properties degradation are all taken account into the analytical model. Thus,the numerical simulation results agree well with the experimental results.Finally,the effect of the fixture on the testing results is characterized. The results show that the incomplete contaction between the fixture and the specimen or the lack of the lateral constraint on the specimen will affect the limited bearing strength and the offset bearing strength of the bolt jointed composite laminates structure. In addition,the lower support rigid of the fixture will affect the rigid of the bolt jointed composite laminates structure.
基金the National Natural Science Foundation of China State Key Projects for Science and Technology during the 8th Five-Year Plan 85906-04-03
文摘The macro and micro cloud physics structures and their evolution with time are the core of describing cloud fields in essence.They are necessary atmospheric environment not only in aviation and spaceflight activities but also for atmos- pheric radiation transfer and acid rain formation research.Unfortunately it is difficult to obtain an entire environmental cloud field by using observation methods directly.Thus,by use of computation physics method to build a cloud-system model may be an indispensable way for this topic.This paper presented a cloud-system model for this goal,and simu- lated a real case.The results of computation showed that the macro structure of the cloud field was better consistent with real observation,and the micro structure was fairly reasonable.The output of model could provide all the information about the cloud field:(1)size-distribution spectrum of hydrometeor particles (point),(2)vertical profile (line),(3)hori- zontal or vertical section of macro and micro parameters (surface),and (4)cloud cover,pattern of cloud and configura- tion of cloud,etc.(body).
基金supported by the National Natural Science Foundation of China(No.51275267)
文摘Ligaments are densely connective soft tissues capable of maintaining stability and function of knee joint.As an important factor,the constitutive relation of ligament would affect its biomechanics and further play an essential role in the research on ligament injury,healing and treatment.The objective of this paper is to provide an overview of the current research on ligament constitutive relations on the macro,meso,and micro levels as well as the anatomy and histological structure of ligament.Some studies of biomechanical behaviors during ligament injury and healing periods have also been investigated.Based on the research on ligament constitutive relation in the past three decades,a discussion of some research perspectives is also presented,such as a validated accurate measuring method of in situ strain in ligament,a new constitutive relation involving the distribution of ultra-structural properties,and a rational estimation of ligament injury and healing process by the change of its ultra-structural or histological characteristics.
文摘Abstract:This article endeavors to investigate the difference and similarities between English abstracts in the field of petroleum written by native academicians and Chinese scholars by means of comparison.It is researched from two aspects:macro-genre structure and micro-linguistic features based on corpus study in order to find out the reason why some articles are good enough to be employed in the international research organization such as EI or SCI,and propose constructive instructions for informative abstract writing.
文摘目的探究3D打印多孔结构陶瓷材料外科植入物孔隙结构的宏微观特征分析及评价方法。方法基于微米X射线CT(Micro-CT)扫描获取的多孔样品图像数据,利用VG Studio MAX 3.0软件及Mimics 16.0软件的多孔结构分析功能,对多孔结构的宏观结构特征包括总孔隙率、宏孔孔径、内连接、开/闭孔率等进行测量和分析;同时,采用扫描电子显微镜对样品表面微观多孔形貌进行特征分析和评价。结果基于Micro-CT和SEM扫描及影像学分析实现了针对3D打印多孔结构陶瓷样件的孔隙结构的宏微观特征表征和统计分析,并验证了其可行性和准确性,形成了一套面向3D打印多孔结构陶瓷材料外科植入物形貌宏微结构尺寸特征的有效的测量和评价方法。结论本文提出的基于Micro-CT和SEM扫描成像进行3D打印多孔结构陶瓷样件的孔隙结构的宏微观特征表征和分析的统计方法,有利于实现多孔结构宏微观特征的相关测试内容和试验过程的规范统一,确保测试过程方法有据可依,结果评价准确有效,有利于提升产品的加工精度,便于不同企业同种工艺制造的多孔结构特征参数之间等同比较,为医疗器械行业多孔结构宏微观特征的数据积累奠定基础,有利于提高与人体生命安全息息相关的外科植入物产品的研发和制造水平。
