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《物体的平衡》学习导引
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作者 袁培耀 《物理教学探讨(高一年级学研期)》 2003年第2期37-39,共3页
关键词 《物体平衡》 学习导引 高中 物理 教学 解题 力学
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《物体的平衡》检测题
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作者 任会常 《物理教学探讨(高一年级学研期)》 2003年第2期77-80,96,共4页
关键词 《物体平衡》 检测题 中学 物理 教学 解题 试题 考试
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《物体的平衡》检测题
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作者 王超良 《物理教学探讨(高一年级学研期)》 2004年第2期51-54,共4页
关键词 《物体平衡》 高一 物理 参考答案
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高中物理教材(试验本)第一册第四章《物体的平衡》教学体会
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作者 汪马生 《中小学教材教学(中学文科)》 2000年第16期39-41,共3页
关键词 高中 物理第一册 教学体会 《物体平衡》
全文增补中
A Hypothesis Regarding the Origin of Additional Surface Acidity in Solid Complexes with Same Metal Cations
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作者 SHAO Bo TONG Chaoli +5 位作者 WANG Jiaqian HAN Zhongkang ZHANG Yan GE Wenfeng WANG Yong YANG Hangsheng 《材料科学与工程学报》 CAS CSCD 北大核心 2024年第5期718-722,共5页
Based on the criteria for additional surface acidity generation in composite oxides and composite fluorides proposed by Tanabe and Kemnitz et al.A hypothesis for the origin of additional surface acidity in solid compo... Based on the criteria for additional surface acidity generation in composite oxides and composite fluorides proposed by Tanabe and Kemnitz et al.A hypothesis for the origin of additional surface acidity in solid composites with the same metal cations is proposed.The surface acidsites of We analyze three types of solid composite systems,that is,CrF_(3)/Cr_(2)O_(3),MgF_(2)/MgO,and ZnF_(2)/ZnO,is systematically analyzed,which agrees with experimental results.Accordingly,the origin of additional surface acidity in these solid composites is reasonably explained,and the types of acidic sites are also predicted. 展开更多
关键词 Surface acidity Solid composite Local charge imbalance
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Gibberellin homeostasis and plant height control by EUI and a role for gibberellin in root gravity responses in rice 被引量:13
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作者 Yingying Zhang Yongyou Zhu +5 位作者 Yu Peng Dawei Yan Qun Li Jianjun Wang Linyou Wang Zuhua He 《Cell Research》 SCIE CAS CSCD 2008年第3期412-421,共10页
The rice Eui (ELONGATED UPPERMOST INTERNODE) gene encodes a cytochrome P450 monooxygenase that deactivates bioactive gibberellins (GAs). In this study, we investigated controlled expression of the Eui gene and its... The rice Eui (ELONGATED UPPERMOST INTERNODE) gene encodes a cytochrome P450 monooxygenase that deactivates bioactive gibberellins (GAs). In this study, we investigated controlled expression of the Eui gene and its role in plant development. We found that Eui was differentially induced by exogenous GAs and that the Eui promoter had the highest activity in the vascular bundles. The eui mutant was defective in starch granule development in root caps and Eui overexpression enhanced starch granule generation and gravity responses, revealing a role for GA in root starch granule development and gravity responses. Experiments using embryoless half-seeds revealed that RAmylA and GAmyb were highly upregulated in eui aleurone ceils in the absence of exogenous GA. In addition, the GA biosynthesis genes GA3oxl and GA20ox2 were downregulated and GA2oxl was upregulated in eui seedlings. These results indicate that EUI is involved in GA homeostasis, not only in the internodes at the heading stage, but also in the seedling stage, roots and seeds. Disturbing GA homeostasis affected the expression of the GA signaling genes GID1 (GIBBERELLIN INSENSITIVE DWARF 1), GID2 and SLR1. Transgenic RNA interference of the Eui gene effectively increased plant height and improved heading performance. By contrast, the ectopic expression of Eui under the promoters of the rice GA biosynthesis genes GA3ox2 and GA2Oox2 significantly reduced plant height. These results demonstrate that a slight increase in Eui expression could dramatically change rice morphology, indicating the practical application of the Eui gene in rice molecular breeding for a high yield potential. 展开更多
关键词 ectopic expression EUI gibberellin homeostasis gravity responses plant height rice
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Mass Loss from Glaciers in the Chinese Altai Mountains between 1959 and 2008 Revealed Based on Historical Maps, SRTM, and ASTER Images 被引量:10
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作者 WEI Jun-feng LIU Shi-yin +4 位作者 XU Jun-li GUO Wan-qin BAO Wei-jia SHANGGUAN Dong-hui JIANG Zong-li 《Journal of Mountain Science》 SCIE CSCD 2015年第2期330-343,共14页
Mass loss of glaciers in the Chinese Altai was detected using geodetic methods based on topographical maps(1959), the Shuttle Radar Topography Mission(SRTM) Digital Elevation Model(DEM)(2000), and the Advanced Space-b... Mass loss of glaciers in the Chinese Altai was detected using geodetic methods based on topographical maps(1959), the Shuttle Radar Topography Mission(SRTM) Digital Elevation Model(DEM)(2000), and the Advanced Space-borne Thermal Emission and Reflection Radiometer(ASTER) stereo images(2008). The results indicate that a continued and accelerating shrinkage has occurred in the Chinese Altai Mountains during the last 50 years, with mass deficits of 0.43 ± 0.02 and0.54 ± 0.13 m a-1 water equivalent(w.e.) during the periods 1959-1999 and 1999-2008, respectively.Overall, the Chinese Altai Mountains have lost 7.06 ±0.44 km3 in ice volume(equivalent to-0.43 ± 0.03 m a-1 w.e.) from 1959-2008. The spatial heterogeneity in mass loss was potentially affected by comprehensive changes in temperature and precipitation, and had a substantial correlation withglacier size and topographic settings. Comparison shows that in the Chinese Altai Mountains glaciers have experienced a more rapid mass loss than those in the Tianshan and northwestern Tibetan Plateau(TP), and the mass balance of glaciers was slightly less negative relative to those in the Russian Altai, Himalaya, and southern TP. 展开更多
关键词 Altai Mountains Geodetic method Glacier change Mass balance
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Nutritive Equilibrium in Rice Plant Populations for High Yield 被引量:3
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作者 WANG BOLUN LIU XINAN +1 位作者 YU GUIRUI SU ZHENGSHU and WANG SU (Shenyang Agricultural University, Shenyang 110161, China) 《Pedosphere》 SCIE CAS CSCD 1999年第1期77-82,共6页
The effects of nitrogen, phosphorus and potassium application level, seed rate and transplanting density on the growth and development of rice plants were studied to find out nutrient status in high-yielding rice plan... The effects of nitrogen, phosphorus and potassium application level, seed rate and transplanting density on the growth and development of rice plants were studied to find out nutrient status in high-yielding rice plants and to increase grain yield by adequate fertilization. There was an equilibrium relationship among nutrient elements for high-yielding rice plant populations. The equilibrium index of nutrient amount, content and distribution in high-yielding rice plants should be generally greater than-2 but less than 2. The optimum nutritive proportion of nitrogen: phosphorus: potassium assimilated by the plants was about 10: 2: 9 at the ripening stage. But the content and the proportion varied with the growth stages. Therefore, the nutrient in rice plant populations should be in a dynamic equilibrium, so as to achieve high yield. 展开更多
关键词 high yield nutritive equilibrium rice plant populations
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Influence of Pore Size,Salinity and Gas Composition upon the Hydrate Formation Conditions 被引量:17
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作者 杨明军 宋永臣 +2 位作者 刘瑜 陈拥军 李清平 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2010年第2期292-296,共5页
An experimental device was set up to study the hydrate formation conditions.Effects of pore size,salinity,and gas composition on the formation and dissociation of hydrates were investigated.The result indicates that t... An experimental device was set up to study the hydrate formation conditions.Effects of pore size,salinity,and gas composition on the formation and dissociation of hydrates were investigated.The result indicates that the induction time for the formation of hydrates in porous media is shorter than that in pure water.The decrease in pore size,by decreasing the size of glass beads,increases the equilibrium pressure when the salinity and temperature are kept constant.In addition,higher salinity causes higher equilibrium pressure when the pore size and temperature are kept constant.It is found that the effects of pore size and salinity on the hydrate equilibrium are quite different.At lower methane concentration,the hydrate equilibrium is achieved at lower pressure and higher temperature. 展开更多
关键词 HYDRATE EQUILIBRIUM pore size SALINITY gas composition
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Application of Equilibrium Partitioning Approach to the Derivation of Sediment Quality Guidelines for Metals in Dianchi Lake 被引量:9
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作者 CHEN Yun-Zeng YANG Hao +3 位作者 ZHANG Zhen-Ke QIN Ming-Zhou JIN Feng LU Jun-Jie 《Pedosphere》 SCIE CAS CSCD 2007年第3期284-294,共11页
For the past 20 years, numerous studies have been carried out on the application of equilibrium partitioning approach (EqPA) for the derivation of sediment quality guidelines (SQGs). However, for metals, few Equil... For the past 20 years, numerous studies have been carried out on the application of equilibrium partitioning approach (EqPA) for the derivation of sediment quality guidelines (SQGs). However, for metals, few Equilibrium-partitioning- based numerical SQGs have been developed or are currently available because of the confounding factors mediating the bioavailability of metals. A study was conducted at Dianchi Lake, which is a heavily eutrophicated lake on the Yunnan- Guizhou Plateau, China with the focus on the measurement of partitioning coefficient (Kp) and SQGs derivation and normalization to acid volatile sulfide (AVS), fine material, and organic carbon. Using new normalization methods, SQGs were formulated for seven metals including copper, zinc, lead, cadmium, chromium, mercury, and arsenic in Dianchi Lake. In Dianchi Lake sediments, the fine material contributed 25.4%-36.0% to the SQG values, with the largest contribution to the SQG value of mercury; AVS contributed 2.9%-75.0% to the SQG values, with the largest contribution to the SQG value of cadmium. This indicated that the fine material and the AVS were the most important controlling factors to the bioavailability of mercury and caximium, respectively. The contribution of total organic carbon (TOC) to the SQG values of copper and leaxi was 3.8% and 7.1%, respectively, indicating that at relatively lower concentrations, the contribution of TOC was not significant. In addition to normalization methods, appropriate procedures for the application of EqPA including sample collection, storage, and analysis are also essential to improve the reliability of SQGs. The normalized Dianchi Lake SQGs were higher than most of the empirically based SQGs developed in North America, but lower than Hong Kong interim SQGs except for cadmium and arsenic. The differences could be attributed to the approaches used for derivation of SQGs and the water quality criteria adopted and the differences in the physical and chemical characteristics of the sediments. 展开更多
关键词 acid volatile sulfide fine material normalization method organic carbon sediment quality guidelines
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中学物理中有关静力学的极值问题及求值方法
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作者 李贵儒 《甘肃教育》 2006年第01B期53-53,共1页
关键词 中学 物理 静力学 极值问题 求值方法 例题解析 《物体平衡》
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Electromotive Force for Solid Oxide Fuel Cells Using Biomass Produced Gas as Fuel 被引量:2
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作者 Wei Zhu Yan-hong Yin +2 位作者 Cen Gao Chang-rong Xia Guang-yao Meng 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2006年第4期325-328,共4页
The electromotive force (e.m.f.) of solid oxide fuel cells using biomass produced gas (BPG) as the fuels is calculated at 700-1,200 K using an in-house computer program, based on thermodynamic equilibrium analysis... The electromotive force (e.m.f.) of solid oxide fuel cells using biomass produced gas (BPG) as the fuels is calculated at 700-1,200 K using an in-house computer program, based on thermodynamic equilibrium analysis. Tour program also predicts the concentration of oxygen in the fuel chamber as well as the concentration of equilibrium species such as H2, CO, CO2 and CH4. Compared with using hydrogen as a fuel, the e.m.f. for cells using BPG as the fuels is relative low and strongly influenced by carbon deposition. To remove carbon deposition, the optimum amount of H2O to add is determined at various operating temperatures. Further the e.m.f, for cells based on yttria stabilized zirconia and doped ceria as electrolytes are compared. The study reveals that when using BPG as fuel, the depression of e.m.f, for a SOFC using doped ceria as electrolyte is relatively small when compared with that using Yttria stabilized zirconia. 展开更多
关键词 Biomass produced gas Electromotive force Solid oxide fuel cells Thermodynamic equilibrium
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Hepatic expression and cellular distribution of the glucose transporter family 被引量:5
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作者 Sumera Karim David H Adams Patricia F Lalor 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第46期6771-6781,共11页
Glucose and other carbohydrates are transported into cells using members of a family of integral membrane glucose transporter (GLUT) molecules. To date 14 members of this family, also called the solute carrier 2A prot... Glucose and other carbohydrates are transported into cells using members of a family of integral membrane glucose transporter (GLUT) molecules. To date 14 members of this family, also called the solute carrier 2A proteins have been identified which are divided on the basis of transport characteristics and sequence similarities into several families (Classes 1 to 3). The expression of these different receptor subtypes varies between different species, tissues and cellular subtypes and each has differential sensitivities to stimuli such as insulin. The liver is a contributor to metabolic carbohydrate homeostasis and is a major site for synthesis, storage and redistribution of carbohydrates. Situations in which the balance of glucose homeostasis is upset such as diabetes or the metabolic syndrome can lead metabolic disturbances that drive chronic organ damage and failure, confirming the importance of understanding the molecular regulation of hepatic glucose homeostasis. There is a considerable literature describing the expression and function of receptors that regulate glucose uptake and release by hepatocytes, the most import cells in glucose regulation and glycogen storage. However there is less appreciation of the roles of GLUTs expressed by non parenchymal cell types within the liver, all of which require carbohydrate to function. A better understanding of the detailed cellular distribution of GLUTs in human liver tissue may shed light on mechanisms underlying disease pathogenesis. This review summarises the available literature on hepatocellular expression of GLUTs in health and disease and highlights areas where further investigation is required. 展开更多
关键词 Hepatic Liver Glucose transporters Glucose Transport Hepatocyte
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Vapor-Liquid Equilibrium of Copolymer+ Solvent Systems: Experimental Data and Thermodynamic Modeling with New UNIFAC Groups
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作者 Roégrio A.G.Sé Martín Aznar 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第4期605-611,共7页
Vapor-liquid equilibrium (VLE) data for copolymer solutions are necessary for several chemical processes. However, VLE data for copolymer solutions in the published report are rare. In this study, experimental VLE d... Vapor-liquid equilibrium (VLE) data for copolymer solutions are necessary for several chemical processes. However, VLE data for copolymer solutions in the published report are rare. In this study, experimental VLE data for binary systems copolymer+solvent were obtained using a gravimetric-sorption apparatus. The studied systems were hexane+poly (21% acrylonitrile-co-butadiene), hexane+poly (33% acrylonitrile-co-butadiene), hexane+poly (51% acrylonitrile-co-butadiene), hexane+poly (23% styrene-co-butadiene), hexane+poly (45% styrene-co-butadiene), and benzene+poly (44% styrene-co-methyl methacrylate) in the range 50-70℃. The experimental data were correlated with the UNIFAC and Elbro-FV group contribution models for the activity coefficient. Two sets of functional groups had been used to represent the monomers in copolymers: literature groups and new proposed groups. The mean deviations between experimental and calculated mass fractions about 2.4% with Elbro- FV and 13.3% with Zhong were observed when the groups proposed in this study were used, and of 3.5% for E1- bro-FV and 13.2% for Zhong, when literature grouns were used. 展开更多
关键词 COPOLYMERS gravimetric sorption vapor-liquid equilibrium
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Computation of three-finger equilibrium and force-closure grasps
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作者 李家炜 刘宏 蔡鹤皋 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2003年第2期157-162,共6页
We proved a new necessary and sufficient condition for 2D three finger equilibrium grasps and implemented an geometrical algorithm for computing force closure grasps of arbitrary 2D objects in this article. The algori... We proved a new necessary and sufficient condition for 2D three finger equilibrium grasps and implemented an geometrical algorithm for computing force closure grasps of arbitrary 2D objects in this article. The algorithm is quite simple and only needs some algebraic calculations. Finally, we implemented the algorithm and confirmed its usefulness by an example. 展开更多
关键词 force closure GRASP dextrous hand
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Prediction of Phase Behavior for Styrene/CO2/Polystyrene Mixtures 被引量:1
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作者 吴家龙 潘勤敏 G.L.Rempel 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2002年第6期706-710,共5页
A lattice fluid model, Sanchez-Lacombe equation, is used to predict the phase behavior for a styrene/CO2/polystyrene ternary sys-tem. The binary parameters involved in the equation were optimized using experimental da... A lattice fluid model, Sanchez-Lacombe equation, is used to predict the phase behavior for a styrene/CO2/polystyrene ternary sys-tem. The binary parameters involved in the equation were optimized using experimental data. Phase diagrams and the distribution coefficients of styrene between polymer phase and fluid phase are obtained over a wide range of pressure, temperature and composition. The analysis of ter-nary phase diagrams indicates that this system at relatively high pressure or low temperature may display two-phase equilibrium, and at low pressures or high temperatures three-phase equilibrium may appear. The distribution coefficients of styrene between the fluid phase and the polymer phase increase asymptotically to unity when the concentration of styrene increases. The results provide thermodynamic knowledge for further exploitation of supercritical carbon dioxide assisted devolatilization and impregnation. 展开更多
关键词 ternary phase diagram distribution coefficient POLYSTYRENE supercritical fluid
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Impact of Solid / Vapour Equilibria on Conditions of Crystallization of Pharmaceutical Compounds
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作者 Cartigny Yohann Coquerel Gerard 《Transactions of Tianjin University》 EI CAS 2013年第1期53-57,共5页
The influence of solvent (in its gaseous state) on the stability of crystallized organic compounds was investigated. Through two examples of studies on the solid/vapour equilibria made in our lab, several behaviors we... The influence of solvent (in its gaseous state) on the stability of crystallized organic compounds was investigated. Through two examples of studies on the solid/vapour equilibria made in our lab, several behaviors were highlighted: (i) a new hydrated phase (thermodynamically stable) of an active pharmaceutical ingredient (API) was detected after the recrystallization starting from a deliquescent state, (ii) a spontaneous resolution of a hydrated racemic compound towards an anhydrous conglomerate can occur during the desolvation under the precise conditions of temperature and humidity. This study illustrates that knowledge about solid/vapour equilibrium is a crucial step during the complete characterization of solid organic compounds. 展开更多
关键词 solid/vapour equilibria hydrates deliquescence pharmaceutical solids dynamic vapour sorption
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Experimental and simulation study of nylon 6 solid–liquid extraction process
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作者 Chunxi Qin Jie Tang +2 位作者 Fenglei Bi Zhenhao Xi Ling Zhao 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第5期1022-1030,共9页
The solid–liquid extraction process of nylon 6 to eliminate small molecules, i.e., caprolactam(CL), cyclic dimers(CD) and cyclic trimers(CT), is investigated in detail by both batch extraction experiments and numeric... The solid–liquid extraction process of nylon 6 to eliminate small molecules, i.e., caprolactam(CL), cyclic dimers(CD) and cyclic trimers(CT), is investigated in detail by both batch extraction experiments and numerical simulations. In the batch extraction experiments, due to the small molecules attaching to the polymeric surface, the basic physical mechanism shifts from surface diffusion to internal diffusion as the extraction proceeded. The experimental data are well reproduced by a diffusion model consisting of two distinct steps, characterized as surface diffusion and internal diffusion. Furthermore, based on the established mass transfer mechanism and diffusion model of the two distinct steps, the equilibrium constants and internal diffusion coefficients of CL, CD and CT are acquired. An industrial countercurrent extraction tower is further simulated. It is found that the extraction efficiency of CL can be significantly improved by increasing the temperature at the bottom portion of the tower. The elimination of CD, which can be greatly promoted by a high-concentration CL-water solution, is controlled by mass transfer resistance, whereas the removal of CL is mainly affected by the equilibrium. 展开更多
关键词 Solid-liquid extraction EQUILIBRIUM DIFFUSION Numerical simulation
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Two New Solutions of Non-constant-α Force-Free Magnetic Field
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作者 XIE Bai-Song 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第3X期561-562,共2页
Two new solutions for non-constant-α force-free magnetic field are found analytically. Implications of the results to astrophysical solar plasmas as well tokamak plasmas are discussed.
关键词 MAGNETOHYDRODYNAMICS magnetic confinement and equilibrium
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Optimal scenario balance of reduction in costs and greenhouse gas emissions for municipal solid waste management 被引量:1
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作者 邓娜 张强 +4 位作者 陈广武 齐长青 崔文谦 张于峰 马洪亭 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第3期887-894,共8页
To reduce carbon intensity, an improved management method balancing the reduction in costs and greenhouse gas(GHG)emissions is required for Tianjin's waste management system. Firstly, six objective functions, name... To reduce carbon intensity, an improved management method balancing the reduction in costs and greenhouse gas(GHG)emissions is required for Tianjin's waste management system. Firstly, six objective functions, namely, cost minimization, GHG minimization, eco-efficiency minimization, cost maximization, GHG maximization and eco-efficiency maximization, are built and subjected to the same constraints with each objective function corresponding to one scenario. Secondly, GHG emissions and costs are derived from the waste flow of each scenario. Thirdly, the range of GHG emissions and costs of other potential scenarios are obtained and plotted through adjusting waste flow with infinitely possible step sizes according to the correlation among the above six scenarios. And the optimal scenario is determined based on this range. The results suggest the following conclusions. 1) The scenarios located on the border between scenario cost minimization and GHG minimization create an optimum curve, and scenario GHG minimization has the smallest eco-efficiency on the curve; 2) Simple pursuit of eco-efficiency minimization using fractional programming may be unreasonable; 3) Balancing GHG emissions from incineration and landfills benefits Tianjin's waste management system as it reduces GHG emissions and costs. 展开更多
关键词 fractional programming greenhouse gas(GHG) emissions eco-efficiency waste management
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