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应用欧拉φ函数研究带电粒子在磁场中的一类特殊运动——基于2023年高考全国理综甲卷第20题的深度思考
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作者 岳国联 《物理通报》 CAS 2024年第7期134-137,共4页
深度研究2023年高考全国理综甲卷第20题,给出带电粒子能够穿出圆筒的条件;应用欧拉φ函数对带电粒子运动轨迹进行了深入研究,给出粒子运动的可能轨迹数目确定表达式,对轨迹形状予以详细讨论;分析了带电粒子在磁场中运动的总时间问题,给... 深度研究2023年高考全国理综甲卷第20题,给出带电粒子能够穿出圆筒的条件;应用欧拉φ函数对带电粒子运动轨迹进行了深入研究,给出粒子运动的可能轨迹数目确定表达式,对轨迹形状予以详细讨论;分析了带电粒子在磁场中运动的总时间问题,给出这一总时间跟粒子与圆筒碰撞次数和粒子在圆筒中绕圆筒轴心运动的圈数之间的约束关系. 展开更多
关键词 欧拉φ函数 轨迹数量 轨迹形状 运动总时间
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Limiting stand density and basal area projection models for even-aged Tecomella undulata plantations in a hot arid region of India
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作者 Vindhya Prasad Tewari 《Journal of Forestry Research》 SCIE CAS CSCD 2010年第1期13-18,I0001,共7页
This paper presents equations for estimating limiting stand density for Z undulata plantations grown in hot desert areas of Raj asthan State in India. Five different stand level basal area projection models, belonging... This paper presents equations for estimating limiting stand density for Z undulata plantations grown in hot desert areas of Raj asthan State in India. Five different stand level basal area projection models, belonging to the path invariant algebraic difference form of a non-linear growth function, were also tested and compared. These models can be used to predict future basal area as a function of stand variables like dominant height and stem number per hectare and are necessary for reviewing different silvicultural treatment options. Data from 22 sample plots were used for modelling. An all possible growth intervals data structure was used. Both, qualitative and quantitative criteria were used to compare alternative models. The Akaike's information criteria differ- ence statistic was used to analyze the predictive ability of the models. Results show that the model proposed by Hui and Gadow performed best and hence this model is recommended for use in predicting basal area development in 12 undulata plantations in the study area. The data used were not from thinned stands, and hence the models may be less accurate when used for predictions when natural mortality is very significant. 展开更多
关键词 model evaluation path invariant algebraic difference form growth function potential density qualitative and quantitative criteria RAJASTHAN
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A unified criterion for yielding behavior of metallic glasses
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作者 宋旼 贺跃辉 《Journal of Central South University》 SCIE EI CAS 2011年第1期1-5,共5页
The yield behavior of metallic glasses was studied. Three yield criteria, including von Mises yield criterion, Mohr-Coulomb yield criterion and the unified yield criterion were used to describe the yield phenomena of ... The yield behavior of metallic glasses was studied. Three yield criteria, including von Mises yield criterion, Mohr-Coulomb yield criterion and the unified yield criterion were used to describe the yield phenomena of the metallic glasses. Two classes of the experimental data were chosen to draw the yield loci using the unified yield criterion. It is shown that the unified yield criterion can be used to describe the yield behavior of the metallic glasses no matter whether the metallic glasses show strength- different effect or non-strength-different effect. Almost all the widely accepted yield criteria are the subsets of the unified yield criterion if the intermediate principle stress and/or the intermediate principle shear stress are not considered at all. 展开更多
关键词 metallic glasses yield criterion unified criterion
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Identification and mapping of quantitative trait loci controlling cold-tolerance of Chinese common wild rice (O. rufipogon Griff.) at booting to flowering stages 被引量:29
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作者 LIU Fengxia, SUN Chuanqing, TAN Lubin, FU Yongcai, LI Dejun & WANG Xiangkun Department of Plant Genetics and Breeding, China Agricultural University, National Key Laboratory of Agrobiology, Key Laboratory of Crop Genetic Improvement and Genome of the Ministry of Agriculture, Beijing 100094, China 《Chinese Science Bulletin》 SCIE EI CAS 2003年第19期2068-2071,共4页
An advanced backcross population of rice was used to identify the quantitative trait locus (QTL) controlling the cold-tolerance at booting to flowering stages. The recipient, Guichao 2 (GC2), was a commercial Indica r... An advanced backcross population of rice was used to identify the quantitative trait locus (QTL) controlling the cold-tolerance at booting to flowering stages. The recipient, Guichao 2 (GC2), was a commercial Indica rice; the donor Dongxiang common wild rice, was an accession of common wild rice (DXCWR, Oryza rufipogon Griff.). Three QTLs for cold-tolerance were detected on chromosomes 1, 6 and 11. Two of them coming from DXCWR could enhance the cold-tolerance of the backcross progenies. Moreover, one sterility QTL that could reduce the seed set rate of the backcross progenies by 78% was mapped on chromosome 5. 展开更多
关键词 耐寒性 水稻 开花期 播种设备 回交杂种 QTL分析 数量特点轨迹
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