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基于信息熵的用水系统结构演化研究 被引量:49
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作者 刘燕 胡安焱 邓亚芝 《西北农林科技大学学报(自然科学版)》 CSCD 北大核心 2006年第6期141-144,共4页
将熵的概念引入水资源系统中,构造了水资源利用结构特征的信息熵和均衡度定量计算公式,用其来表征水资源开发利用的合理性,结合熵变理论给出了水资源系统结构演化的判别标准,并在渭河流域关中地区进行应用。使用结果表明:渭河流域水资... 将熵的概念引入水资源系统中,构造了水资源利用结构特征的信息熵和均衡度定量计算公式,用其来表征水资源开发利用的合理性,结合熵变理论给出了水资源系统结构演化的判别标准,并在渭河流域关中地区进行应用。使用结果表明:渭河流域水资源开发利用结构正向着更加合理、均衡的方向演化。该结果表明信息熵能为人类水资源利用规划调控提供依据。 展开更多
关键词 水资源系统 信息熵 系统结构演化 渭河流域
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悬铃木幼苗的初生维管系统演化结构研究
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作者 王桂文 高伟 +6 位作者 张立秋 王世东 李岩 由继红 刘丹丹 朱军 陆静梅 《东北师大学报(自然科学版)》 CAS 北大核心 2021年第1期110-115,共6页
利用石蜡连续切片方法对悬铃木(Platanus acerifolia Willd.)幼苗初生维管系统进行了研究.结果表明:二球悬铃木具有较长的子叶节区,几乎占幼苗下胚轴的全部;根端为外始式二原型(或真二原假四原)辐射中柱;子叶节区下部的结构较原始,具有... 利用石蜡连续切片方法对悬铃木(Platanus acerifolia Willd.)幼苗初生维管系统进行了研究.结果表明:二球悬铃木具有较长的子叶节区,几乎占幼苗下胚轴的全部;根端为外始式二原型(或真二原假四原)辐射中柱;子叶节区下部的结构较原始,具有中始式二原型单中柱;中部出现具髓的中始式二原型管状中柱阶段;上部与茎的内始式真中柱极为相似且较短,所以只存在子叶节区茎结构连接区;上胚轴的苗区具有内始式真中柱;由于二球悬铃木幼苗子叶节区结构具有中始式二原型单中柱,子叶为二叶迹;而胚芽起源的营养叶为三叶迹;幼苗子叶节区类型属于顶枝伸长型,结构原始. 展开更多
关键词 悬铃木 幼苗 子叶节区 系统结构演化
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A New Liouville Integrable Hamiltonian System 被引量:1
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作者 郭福奎 张玉峰 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第5期809-811,共3页
With the help of a Lie algebra, an isospectral Lax pair is introduced for which a new Liouville integrable hierarchy of evolution equations is generated. Its Hamiltonian structure is also worked out by use of the quad... With the help of a Lie algebra, an isospectral Lax pair is introduced for which a new Liouville integrable hierarchy of evolution equations is generated. Its Hamiltonian structure is also worked out by use of the quadratic-form identity. 展开更多
关键词 Lie algebra Hamiltonian structure quadratic-form identity
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Evolution of Spiral Waves in Excitable Systems
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作者 REN Ji-Rong ZHU Tao MO Shu-Fan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第4期621-626,共6页
Spiral waves, whose rotation center can be regarded as a point defect, widely exist in various two-dimensional excitable systems. In this paper, by making use of Duan's topological current theory, we obtain the charg... Spiral waves, whose rotation center can be regarded as a point defect, widely exist in various two-dimensional excitable systems. In this paper, by making use of Duan's topological current theory, we obtain the charge density of spiral waves and the topological inner structure of its topological charge. The evolution of spiral wave is also studied from the topological properties of a two-dimensional vector field. The spiral waves are found generating or annihilating at the limit points and encountering, splitting, or merging at the bifurcation points of the two-dimensional vector field. Some applications of our theory are also discussed. 展开更多
关键词 topological current spiral wave bifurcation theory of spiral wave
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New Homoclinic and Heteroclinic Solutions for Zakharov System
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作者 王传坚 戴正德 母贵 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第11期749-753,共5页
A new type of homoclinic arid heteroclinic solutions, i.e. homoclinic and heteroclinic breather solutions, for Zakharov system are obtained using extended homoclinic test and two-soliton methods, respectively. Moreove... A new type of homoclinic arid heteroclinic solutions, i.e. homoclinic and heteroclinic breather solutions, for Zakharov system are obtained using extended homoclinic test and two-soliton methods, respectively. Moreover, the homoclinic and heteroclinic structure with local oscillation and mechanicaL feature different from homoclinic and heterocliunic solutions are investigated. Result shows complexity of dynamics for complex nonlineaR evolution system. Moreover, the similarities and differences between homoclinic (heteroclinic) breather and homoclinic (heteroclinic) tube are exhibited. These results show that the diversity of the structures of homoclinic and heteroclinic solutions. 展开更多
关键词 homoclinic wave heteroclinic wave breather type homoclinic test Zakharov system
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