Taking the traditional residential street space in Pingtan Comprehensive Experimental Area as an example,the factors influencing the formation and development of lane space and the distribution characteristics of lane...Taking the traditional residential street space in Pingtan Comprehensive Experimental Area as an example,the factors influencing the formation and development of lane space and the distribution characteristics of lanes were analyzed in this paper.Subsequently,an analysis was conducted on the scale and proportion of street and lane space enclosed in the settlement,the experiential aspects of street and lane space,as well as the node space.Lastly,a systematic summary of the street space characteristics in the settlements of Pingtan Island and Dongxiang Island is presented.展开更多
L3414 mechanized mining working face (No.14 coal seam) of Lingxin Mine is under the Xitian River.The mining disturbed zone where rock properties and conditions have been changed due to mining, the safety and environme...L3414 mechanized mining working face (No.14 coal seam) of Lingxin Mine is under the Xitian River.The mining disturbed zone where rock properties and conditions have been changed due to mining, the safety and environmental protection were con- cemed greatly. Based on engineering geological environment of L3414 working face and mining factors, the color bore-bole TV inspecting, leakage of drilling fluid monitoring, simulation experiment, numerical computing, in-situ ground stress measurement and subsidence measurement, etal, these programs contribute to the formation of a scientific basis for control water safe mining and normal mining or environmental protection in the condition of existing fully-mechanized mining.展开更多
The explosive reaction degree and protection from explosions are concerns in the military field.In this work,the reaction degree of the composition B explosive was investigated experimentally.Multi-layered compound st...The explosive reaction degree and protection from explosions are concerns in the military field.In this work,the reaction degree of the composition B explosive was investigated experimentally.Multi-layered compound structures were used as barriers to weaken the blast loads.A comprehensive experiment using a high-speed camera and image processing techniques,side witness plates,and bottom witness plates was presented.Using the experimental fragment velocities,fragment piercing patterns,and damage characteristics,the reaction degree of the explosive impeded by different multi-layered compound structures could be precisely differentiated.Reaction parameters of the explosive obstructed by compound structures were obtained by theoretical analysis and numerical simulations.Unlike the common method in which the explosive reaction degree is only distinguished based on the initial pressure amplitude transmitted into the explosive,a following shock wave reflected from the side steel casing was also considered.Different detonation growth paths in the explosive formed.Therefore,all these shock wave propagation characteristics must be considered to analyze the explosive response impeded by compound structures.展开更多
Pharmaceutical comprehensive study(PCS) is a new system of experimental teaching in China, which integrates multidisciplinary pharmaceutical knowledge and covers the basic process of new drug discovery. To explore the...Pharmaceutical comprehensive study(PCS) is a new system of experimental teaching in China, which integrates multidisciplinary pharmaceutical knowledge and covers the basic process of new drug discovery. To explore the feasibility of this experiment teaching system and mode, we developed PCS as an elective course. The PCS is designed with two sections: pharmaceutical comprehensive design(PCD) and pharmaceutical comprehensive experiment(PCE). The PCD section includes literature review, comprehensive project design and oral examination. PCE can be divided into four parts: synthesis, quantitative determination, pharmacodynamic evaluation, and formulation and quality determination. Course grade was determined by experimental performance, written report, literature review, new project design and oral examination. The learning interest, experimental ability, theoretical level and literature retrieval ability, team spirit and interpersonal skills have been all significantly improved among students taking this course. A survey was administered at the end of the semester to the enrolled students. The responses were reported as percentages, and the feedback was positive. The course was highly recommended by the teaching inspection committee. This new course plays an important role in developing students’ creativity and comprehensive ability. It could help students understand the focus and features of every secondary discipline, as well as establish scientific and reasonable knowledge system. Most students can better understand the process of drug research after this course.展开更多
Using data on leaf area density and wind profiles above and within canopies of wheat,rice,soybean and corn,the center-of-pressure method (CPM),originally proposed by Thom (1971),is first validated in the field.A physi...Using data on leaf area density and wind profiles above and within canopies of wheat,rice,soybean and corn,the center-of-pressure method (CPM),originally proposed by Thom (1971),is first validated in the field.A physically-based model for directly calculating zero-displacement height (d) is derived.The comparison between the friction velocity (u_*) estimated with CPM and that with eddy correlation technique shows that CPM not only works well in the field,but also produces more steady and accurate estimates of aerodynamic parameters (which are hardly affected by atmospheric thermal stability),than those with the widely-used log-profile fitting method in diabatic atmosphere. The results presented in this paper also demonstrate that the ratios of d,z_0 to crop height h usually vary with canopy ar- chitecture,atmospheric stratification and turbulent exchange intensity,and are not just constants as commonly assumed or used.d/h raises with an increase of relative height of the maximum foliage layer and wind extinction coefficient within the canopy.Only for crops with short stem and moderate foliage density,can the relations d= 0.64h,z_0=0.08h keep stable.In addition,for long stem crops or sparse canopies,the fairly large shear stress at the soil surface and the va- riation of the exponent in the relationship between drag coefficient and wind speed undoubtedly influence the accuracy of CPM to a certain extent.展开更多
文摘Taking the traditional residential street space in Pingtan Comprehensive Experimental Area as an example,the factors influencing the formation and development of lane space and the distribution characteristics of lanes were analyzed in this paper.Subsequently,an analysis was conducted on the scale and proportion of street and lane space enclosed in the settlement,the experiential aspects of street and lane space,as well as the node space.Lastly,a systematic summary of the street space characteristics in the settlements of Pingtan Island and Dongxiang Island is presented.
基金Supported by National Science Foundation(10402033) Ministry of Education Key Lab.of West Mining and Hazard Control Key Research Founda-tion(04JS19) and Shaanxi Province Natural Science (2003E213)
文摘L3414 mechanized mining working face (No.14 coal seam) of Lingxin Mine is under the Xitian River.The mining disturbed zone where rock properties and conditions have been changed due to mining, the safety and environmental protection were con- cemed greatly. Based on engineering geological environment of L3414 working face and mining factors, the color bore-bole TV inspecting, leakage of drilling fluid monitoring, simulation experiment, numerical computing, in-situ ground stress measurement and subsidence measurement, etal, these programs contribute to the formation of a scientific basis for control water safe mining and normal mining or environmental protection in the condition of existing fully-mechanized mining.
基金The authors are very grateful for the support received from the National Natural Science Foundation of China(No.11872121).
文摘The explosive reaction degree and protection from explosions are concerns in the military field.In this work,the reaction degree of the composition B explosive was investigated experimentally.Multi-layered compound structures were used as barriers to weaken the blast loads.A comprehensive experiment using a high-speed camera and image processing techniques,side witness plates,and bottom witness plates was presented.Using the experimental fragment velocities,fragment piercing patterns,and damage characteristics,the reaction degree of the explosive impeded by different multi-layered compound structures could be precisely differentiated.Reaction parameters of the explosive obstructed by compound structures were obtained by theoretical analysis and numerical simulations.Unlike the common method in which the explosive reaction degree is only distinguished based on the initial pressure amplitude transmitted into the explosive,a following shock wave reflected from the side steel casing was also considered.Different detonation growth paths in the explosive formed.Therefore,all these shock wave propagation characteristics must be considered to analyze the explosive response impeded by compound structures.
基金The Education and Teaching Research Project of Peking University Health Science Center
文摘Pharmaceutical comprehensive study(PCS) is a new system of experimental teaching in China, which integrates multidisciplinary pharmaceutical knowledge and covers the basic process of new drug discovery. To explore the feasibility of this experiment teaching system and mode, we developed PCS as an elective course. The PCS is designed with two sections: pharmaceutical comprehensive design(PCD) and pharmaceutical comprehensive experiment(PCE). The PCD section includes literature review, comprehensive project design and oral examination. PCE can be divided into four parts: synthesis, quantitative determination, pharmacodynamic evaluation, and formulation and quality determination. Course grade was determined by experimental performance, written report, literature review, new project design and oral examination. The learning interest, experimental ability, theoretical level and literature retrieval ability, team spirit and interpersonal skills have been all significantly improved among students taking this course. A survey was administered at the end of the semester to the enrolled students. The responses were reported as percentages, and the feedback was positive. The course was highly recommended by the teaching inspection committee. This new course plays an important role in developing students’ creativity and comprehensive ability. It could help students understand the focus and features of every secondary discipline, as well as establish scientific and reasonable knowledge system. Most students can better understand the process of drug research after this course.
文摘Using data on leaf area density and wind profiles above and within canopies of wheat,rice,soybean and corn,the center-of-pressure method (CPM),originally proposed by Thom (1971),is first validated in the field.A physically-based model for directly calculating zero-displacement height (d) is derived.The comparison between the friction velocity (u_*) estimated with CPM and that with eddy correlation technique shows that CPM not only works well in the field,but also produces more steady and accurate estimates of aerodynamic parameters (which are hardly affected by atmospheric thermal stability),than those with the widely-used log-profile fitting method in diabatic atmosphere. The results presented in this paper also demonstrate that the ratios of d,z_0 to crop height h usually vary with canopy ar- chitecture,atmospheric stratification and turbulent exchange intensity,and are not just constants as commonly assumed or used.d/h raises with an increase of relative height of the maximum foliage layer and wind extinction coefficient within the canopy.Only for crops with short stem and moderate foliage density,can the relations d= 0.64h,z_0=0.08h keep stable.In addition,for long stem crops or sparse canopies,the fairly large shear stress at the soil surface and the va- riation of the exponent in the relationship between drag coefficient and wind speed undoubtedly influence the accuracy of CPM to a certain extent.
