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基于MaxEnt模拟三叶海棠的地理分布 被引量:5
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作者 杨俊仙 王雷宏 徐小牛 《西北农林科技大学学报(自然科学版)》 CSCD 北大核心 2013年第7期172-176,182,共6页
【目的】用已有的采集标本分布记录,模拟三叶海棠的地理分布。【方法】从中国4个标本馆获取三叶海棠的291个分布数据,从WorldClim网站下载1950-2000年生物气候数据,用最大熵模型(MaxEnt)模拟其地理分布。【结果】①三叶海棠的潜在分布... 【目的】用已有的采集标本分布记录,模拟三叶海棠的地理分布。【方法】从中国4个标本馆获取三叶海棠的291个分布数据,从WorldClim网站下载1950-2000年生物气候数据,用最大熵模型(MaxEnt)模拟其地理分布。【结果】①三叶海棠的潜在分布地区有:巴基斯坦东北部;不丹中部、东北部;印度东北部;中国西藏东南部、河北省东北部和北京西部山区。②依据模拟分布值0.5~0.7标定的三叶海棠分布区域,排除其潜在分布区域,再结合这些区域的地理间隔性,从宏观景观上将三叶海棠的地理分布格局划分为4个区块:中国四川、甘肃、陕西三省交界地区;中国重庆大部分地区,贵州大部分地区,湖北西南部,湖南大部分地区,广西与贵州、湖南交界地区,江西,广东与湖南、江西交界地区,福建东北部,浙江大部分地区,安徽南部;韩国南部沿海地区;日本岛大部分地区。③刀切法检测表明,温暖季节平均降雨量对三叶海棠的分布增益贡献最大,三叶海棠喜生于温暖季节平均降雨量在450~800mm的地区。【结论】用MaxEnt模拟三叶海棠的地理分布有一定的准确性,反映出了三叶海棠基本的地理分布格局和潜在分布区域,并阐明了主导其地理分布的生物气候因子。 展开更多
关键词 三叶海棠 MaxEnt模型 地理分布
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Approximate Generalized Conditional Symmetries for the Perturbed General KdV-Burgers Equation 被引量:3
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作者 张顺利 五鹏洲 屈长征 《Chinese Physics Letters》 SCIE CAS CSCD 2006年第10期2625-2628,共4页
The approximate generalized conditional symmetry (AGCS) approach we previously proposed [Chin. Phys.Lett. 23 (2006) 527] is applied to study the perturbed general KdV-Burgers (KdVB) equation. Complete classifica... The approximate generalized conditional symmetry (AGCS) approach we previously proposed [Chin. Phys.Lett. 23 (2006) 527] is applied to study the perturbed general KdV-Burgers (KdVB) equation. Complete classification of those perturbed general KdVB equations which admit certain types of A GCSs is obtained. Approximate solutions to the perturbed equations can be derived from the corresponding unperturbed ones. 展开更多
关键词 SOLITARY-WAVE SOLUTIONS de-vries EQUATION DECOMPOSITION METHOD PARAMETER
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Grammian Solutions to a Non-Isospectral Kadomtsev-Petviashvili Equation 被引量:1
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作者 张大军 《Chinese Physics Letters》 SCIE CAS CSCD 2006年第9期2349-2351,共3页
Solutions in the Crammian form for a non-isospectral Kadomtsev-Petviashvili equation are derived by means of Pfaffian derivative formulae. Explicit entries of the Crammian are given. Non-isospectral dynamics of the so... Solutions in the Crammian form for a non-isospectral Kadomtsev-Petviashvili equation are derived by means of Pfaffian derivative formulae. Explicit entries of the Crammian are given. Non-isospectral dynamics of the solutions generated from the Crammian are investigated in an analytic way. The solutions obtained can describe line solitons in non-uniform media travelling with time-dependent amplitude and time-dependent direction. In addition, some other solutions have singularities. 展开更多
关键词 N-SOLITON SOLUTIONS de-vries EQUATION WRONSKIAN TECHNIQUE KORTEWEG-DEVRIES TERMS FORM
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Exact Solutions for a Nonisospectral and Variable-Coefficient Kadomtsev-Petviashvili Equation 被引量:1
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作者 邓淑芳 《Chinese Physics Letters》 SCIE CAS CSCD 2006年第7期1662-1665,共4页
The bilinear form for a nonisospectral and variable-coefficient Kadomtsev-Petviashvili equation is obtained and some exact soliton solutions are derived by the Hirota method and Wronskian technique. We also derive the... The bilinear form for a nonisospectral and variable-coefficient Kadomtsev-Petviashvili equation is obtained and some exact soliton solutions are derived by the Hirota method and Wronskian technique. We also derive the bilinear Backlund transformation from its Lax pairs and find solutions with the help of the obtained bilinear Bgcklund transformation. 展开更多
关键词 de-vries EQUATION NONUNIFORMITY TERMS KORTEWEG-DEVRIES SOLITONS
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