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冬小麦丰抗13缺体系和双单体系研究
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作者 孙荣锦 杨之刚 《作物品种资源》 1996年第4期18-18,20,共2页
冬小麦丰抗13缺体系和双单体系研究孙荣锦杨之刚(中国农业科学院作物所,北京100081)1丰抗13缺体系小麦染色体组成是2n=6x=42,小麦缺体是2n-2=40,即缺少了某对染色体的单株,称缺体株。它的减数分裂中期... 冬小麦丰抗13缺体系和双单体系研究孙荣锦杨之刚(中国农业科学院作物所,北京100081)1丰抗13缺体系小麦染色体组成是2n=6x=42,小麦缺体是2n-2=40,即缺少了某对染色体的单株,称缺体株。它的减数分裂中期Ⅰ染色体构型是20″即20个二价体... 展开更多
关键词 冬小麦 丰抗13 染色体 体系 双单体系
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行波输入下双单自由度体系结构的最大振动相对位移
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作者 周光伟 李建中 陈昌萍 《中南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2013年第8期3512-3519,共8页
在地震行波输入下,双单自由度体系结构由于行波激励引起的不同向振动会导致较大的相对位移。基于随机振动理论方法,首先推导行波输入下双单自由度体系结构最大振动的相对位移公式,然后分析该结构的结构动力特性对相关系数的影响。研究... 在地震行波输入下,双单自由度体系结构由于行波激励引起的不同向振动会导致较大的相对位移。基于随机振动理论方法,首先推导行波输入下双单自由度体系结构最大振动的相对位移公式,然后分析该结构的结构动力特性对相关系数的影响。研究结果表明:结构的相关系数及其幅值会随着两相邻结构基本周期数值的接近而增大,相关系数会随着结构阻尼比的增大而增大。然后在相关系数的幅值特性进行研究和参数分析结果的基础上提出了最小周期比限值拟合曲线,结果表明当双单自由度体系结构的最小周期比小于最小周期比限值时,系统的最大振动相对位移计算公式中可以忽略相关系数的影响,从而使计算大为简化。最后通过工程实例描述最大振动相对位移计算公式的工程应用。研究结果对该类体系结构在实际工程中的应用具有一定的理论和指导意义。 展开更多
关键词 双单自由度体系结构 振动相对位移 行波 相关系数 地震
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A new reaction system to determine nonlinear chemical fingerprint and its use in Panax ginseng identification method based on double reaction system 被引量:4
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作者 TAN Xue-ying DENG Fei-yue +2 位作者 ZHANG Tai-ming HUANG Jian CHEN Chun-nan 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第8期1895-1903,共9页
A new reaction system to determine nonlinear chemical fingerprint(NCF)and its use in identification method based on double reaction system was researched.Panax ginsengs,such as ginseng,American ginseng and notoginseng... A new reaction system to determine nonlinear chemical fingerprint(NCF)and its use in identification method based on double reaction system was researched.Panax ginsengs,such as ginseng,American ginseng and notoginseng were identified by the method.The NCFs of the three samples of Panax ginsengs were determined through two nonlinear chemical systems,namely system 1 consisting of sample components,H2SO4,MnSO4,NaBrO3,acetone and the new system,system 2 consisting of sample components,H2SO4,(NH4)4Ce(SO4)2,NaBrO3 and citric acid.The comparison between the results determined through systems 1 and 2 shows that the speed to determine NCF through system 2 is much faster than that through system 1;for systems 1 and 2,the system similarities of the same kind of samples are≥98.09%and 99.78%,respectively,while those of different kinds of samples are≤63.04%and 86.34%,respectively.The results to identify the kinds of some samples by system similarity pattern show that both the accuracies of identification methods based on single system 1 and 2 are≥95.6%,and the average values are 97.1%and 96.3%,respectively;the accuracy of the method based on double system is≥97.8%,and the average accuracy is 99.3%.The accuracy of the method based on double system is higher than that based on any single system. 展开更多
关键词 nonlinear chemical fingerprint double reaction system single reaction system authenticity identification Panax ginsengs
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Analyzing Nonstationary Random Response of a SDOF System under the Evolutionary Random Excitation by Wavelet Transform
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作者 李方兵 张天舒 《Journal of Donghua University(English Edition)》 EI CAS 2006年第4期94-97,共4页
For evolutionary random excitations, a general method of analyzing nonstationary random responses of systems was presented in this paper. Firstly, for the evolutionary random excitation model, the evolutionary power s... For evolutionary random excitations, a general method of analyzing nonstationary random responses of systems was presented in this paper. Firstly, for the evolutionary random excitation model, the evolutionary power spectrum density function (EPSD) of a random excitation was given by wavelet transform. Based on the EPSD, the nonstationary responses of a SDOF system subjected to evolutionary random excitations were studied. The application and validity of presented method were illustrated by numerical examples. In numerical examples, the recently developed stochastic models for El Centro (1934) and Mexico City (1985) earthquakes which preserve the nonstationary evolutions of amplitude and frequency content of ground accelerations were used as excitations. The nonstationary random mean-square responses of a SDOF system under these two excitations were evaluated and compared with simulated results. 展开更多
关键词 evolutionary random excitation wavelet transform nonstationary random response.
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