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Weak type heterodimensional cycle bifurcation with orbit-flip 被引量:4
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作者 LU QiuYing ZHU DeMing GENG FengJie 《Science China Mathematics》 SCIE 2011年第6期1175-1196,共22页
In this paper, we study the weak type heterodimensional cycle with orbit-flip in its non-transversal orbit by using the local moving frame approach. For the first two subcases, we present the sufficient conditions for... In this paper, we study the weak type heterodimensional cycle with orbit-flip in its non-transversal orbit by using the local moving frame approach. For the first two subcases, we present the sufficient conditions for the existence, uniqueness and non-coexistence of the homoclinic orbit, heteroclinic orbit and periodic orbit. Based on the bifurcation analysis, the bifurcation surfaces and the existence regions are located. And for the third subcase, we theoretically established both the coexistence condition for the homoclinic loop and the periodic orbit and the coexistence condition for the persistent heterodimensional cycle and multiple periodic orbits due to the weak type of the transversal heteroclinic orbit. Moreover, an analytical example is presented for this subcase. 展开更多
关键词 local moving frame weak heterodimensional cycle orbit-flip
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“双原子分子结构”量子化学模拟实验翻转课堂教学初探 被引量:2
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作者 庾弘朗 《广东化工》 2025年第7期167-169,共3页
本案例建议将简单量子化学计算实验融入“双原子分子结构”的翻转课堂教学之中。基于超星慕课平台,教师预先构建在线学习资源,学生课前自主学习。实验课中学生自主采用B3LYP理论方法与AUG-cc-pV5Z基组,对目标双原子分子进行结构优化与... 本案例建议将简单量子化学计算实验融入“双原子分子结构”的翻转课堂教学之中。基于超星慕课平台,教师预先构建在线学习资源,学生课前自主学习。实验课中学生自主采用B3LYP理论方法与AUG-cc-pV5Z基组,对目标双原子分子进行结构优化与频率计算,确定分子基态并获取基态的总电子能、键长、能级、键能等参数,并借助GaussView5.0软件辨析N2基态的分子轨道类型。然后通过自然键轨道分析,探究N2的分子轨道组成与成键性质。最后,根据计算结果,学生绘制N2的分子轨道能级图。 展开更多
关键词 结构化学 翻转课堂 Gaussian09 自然键轨道分析 本科生
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具有共振特征值的轨道翻转双同宿环分支
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作者 张天四 朱德明 《应用数学和力学》 CSCD 北大核心 2007年第11期1353-1362,共10页
该文研究了具有轨道翻转的双同宿环四维系统,在主特征值共振和沿轨道奇点处切方向共振下的两种分支.我们分别在系统奇点小邻域内利用规范型的解构造一个奇异映射,再在双同宿环的管状邻域内引起局部活动坐标架,利用系统线性变分方程的解... 该文研究了具有轨道翻转的双同宿环四维系统,在主特征值共振和沿轨道奇点处切方向共振下的两种分支.我们分别在系统奇点小邻域内利用规范型的解构造一个奇异映射,再在双同宿环的管状邻域内引起局部活动坐标架,利用系统线性变分方程的解定义了一个正则映射,通过复合两个映射而得到分支研究中一类重要的Poincaré映射,经过简单的计算最终得到后继函数的精确表达式.对分支方程细致地研究,我们给出了原双同宿环的保存性条件,并证明了"大"1-同宿环分支曲面,2-重"大"1-周期轨分支曲面,"大"2-同宿环分支曲面的存在性、存在区域和近似表达式,及其分支出的"大"周期轨和"大"同宿轨的存在性区域和数量. 展开更多
关键词 双同宿轨 轨道翻转 周期轨 共振
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倾斜翻转同宿分支中的同宿轨与周期轨的共存性
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作者 水树良 傅新楚 《上海大学学报(自然科学版)》 CAS CSCD 北大核心 2006年第5期473-476,480,共5页
在同宿轨附近建立活动坐标架可研究向量场的同宿轨分支.该文在已有的关于1-周期轨的存在条件、个数及与倾斜翻转强度的相关依赖性方面结论的基础上,进一步研究这类分支的同宿轨与周期轨的共存性.主要结论为这类系统在分支出一个同宿轨... 在同宿轨附近建立活动坐标架可研究向量场的同宿轨分支.该文在已有的关于1-周期轨的存在条件、个数及与倾斜翻转强度的相关依赖性方面结论的基础上,进一步研究这类分支的同宿轨与周期轨的共存性.主要结论为这类系统在分支出一个同宿轨的同时所能分支出的周期轨的个数也依赖于倾斜翻转的强度. 展开更多
关键词 分支 同宿轨 倾斜翻转 1-周期轨
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Rashba自旋-轨道相互作用对一维谐振子势场中电子性质的影响
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作者 公卫江 范爽 +2 位作者 魏国柱 杜安 刘国良 《大学物理》 北大核心 2011年第10期11-14,共4页
分析了Rashba自旋-轨道相互作用对一维谐振子势场中电子性质的影响,发现该自旋-轨道相互作用能够导致能级之间的自旋翻转,并且自旋翻转的性质明显依赖于自旋-轨道耦合系数和参考系坐标之间的关系.
关键词 自旋-轨道相互作用 自旋翻转 能级移动
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翻转课堂与PBL教学法相结合在杂化轨道理论教学中的应用 被引量:2
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作者 秦秀英 马献力 《广东化工》 CAS 2018年第4期181-182,174,共3页
无机化学是大学化学专业及其相关专业的第一门化学课程,是化学人生漫漫不归路的开始。学好无机化学,才能为后续化学课程奠定基础。本文结合翻转课堂与PBL教学法的优点与缺陷,将两者结合应用到无机化学的杂化轨道理论的教学中,进行了设... 无机化学是大学化学专业及其相关专业的第一门化学课程,是化学人生漫漫不归路的开始。学好无机化学,才能为后续化学课程奠定基础。本文结合翻转课堂与PBL教学法的优点与缺陷,将两者结合应用到无机化学的杂化轨道理论的教学中,进行了设计与应用,为教师的教学和学生的自学提供一定的参考。 展开更多
关键词 翻转课堂 PBL教学法 结合 无机化学 杂化轨道理论
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External Bifurcations of Double Heterodimensional Cycles with One Orbit Flip 被引量:1
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作者 Huimiao Dong Tiansi Zhang 《Applied Mathematics》 2021年第4期348-369,共22页
In this paper, external bifurcations of heterodimensional cycles connecting three saddle points with one orbit flip, in the shape of “∞”, are studied in three-dimensional vector field. We construct a poincaré ... In this paper, external bifurcations of heterodimensional cycles connecting three saddle points with one orbit flip, in the shape of “∞”, are studied in three-dimensional vector field. We construct a poincaré return map between returning points in a transverse section by establishing a locally active coordinate system in the tubular neighborhood of unperturbed double heterodimensional cycles, through which the bifurcation equations are obtained under different conditions. Near the double heterodimensional cycles, the authors prove the preservation of “∞”-shape double heterodimensional cycles and the existence of the second and third shape heterodimensional cycle and a large 1-heteroclinic cycle connecting with P<sub>1</sub> and P<sub>3</sub>. The coexistence of a 1-fold large 1-heteroclinic cycle and the “∞”-shape double heterodimensional cycles and the coexistence conditions are also given in the parameter space. 展开更多
关键词 Double Heteroclinic Loops Orbit Flip Heteroclinic Bifurcation Bifurcation Theory
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自旋轨道耦合对铁磁/半导体/绝缘体多层膜结构中隧穿性质的影响
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作者 王文军 何雷 王亚新 《河北师范大学学报(自然科学版)》 CAS 北大核心 2007年第2期191-194,共4页
利用传递矩阵方法,计算了自旋轨道耦合对铁磁/半导体/绝缘体多层膜结构中隧穿性质的影响.结果表明,当半导体和铁磁体之间是绝缘接触时,体系的输运性质发生明显改变,同时出现了自旋反转效应.
关键词 自旋轨道耦合 铁磁体 半导体 绝缘体 自旋反转
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Bifurcations of double homoclinic flip orbits with resonant eigenvalues
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作者 张天四 朱德明 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2007年第11期1517-1526,共10页
Concerns double homoclinic loops with orbit flips and two resonant eigenvalues in a four-dimensional system. We use the solution of a normal form system to construct a singular map in some neighborhood of the equilibr... Concerns double homoclinic loops with orbit flips and two resonant eigenvalues in a four-dimensional system. We use the solution of a normal form system to construct a singular map in some neighborhood of the equilibrium, and the solution of a linear variational system to construct a regular map in some neighborhood of the double homoclinic loops, then compose them to get the important Poincaré map. A simple calculation gives explicitly an expression of the associated successor function. By a delicate analYSiS of the bifurcation equation, we obtain the condition that the original double homoclinic loops are kept, and prove the existence and the existence regions of the large 1-homoclinic orbit bifurcation surface, 2-fold large 1-periodic orbit bifurcation surface, large 2-homoclinic orbit bifurcation surface and their approximate expressions. We also locate the large periodic orbits and large homoclinic orbits and their number. 展开更多
关键词 double homoclinic orbits orbit flip periodic orbit resonance
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运载火箭任务降级轨迹规划问题特性分析研究 被引量:5
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作者 周鼎 梁艳迁 +2 位作者 梁建国 陈尔康 赵俊淇 《上海航天(中英文)》 CSCD 2020年第S02期53-58,70,共7页
对运载火箭非致命故障下的任务降级轨迹规划问题进行了研究。考虑降级轨道目标点未知带来的终端状态不确定情况,利用离散配点选取时考虑终端状态的flipped Radau伪谱法将连续最优控制问题转化为代数约束的非线性规划问题。分别针对某型... 对运载火箭非致命故障下的任务降级轨迹规划问题进行了研究。考虑降级轨道目标点未知带来的终端状态不确定情况,利用离散配点选取时考虑终端状态的flipped Radau伪谱法将连续最优控制问题转化为代数约束的非线性规划问题。分别针对某型运载火箭三子级推力下降无滑行和考虑滑行的情况,从初始轨迹敏感度、求解收敛精度等方面对任务降级轨迹规划问题的特性展开数值实验与分析,为后续工程实施提供基础支撑。 展开更多
关键词 运载火箭 任务降级 轨迹规划 推力下降 flipped Radau伪谱
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Bifurcation Analysis of Homoclinic Flips at Principal Eigenvalues Resonance
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作者 Tiansi Zhang Deming Zhu 《Applied Mathematics》 2013年第2期271-278,共8页
One orbit flip and two inclination flips bifurcation is considered with resonant principal eigenvalues. We introduce a local active coordinate system to establish bifurcation equation and obtain the conditions when th... One orbit flip and two inclination flips bifurcation is considered with resonant principal eigenvalues. We introduce a local active coordinate system to establish bifurcation equation and obtain the conditions when the original homoclinic orbit is kept or broken. We also prove the existence and the existence regions of double 1-periodic orbit bifurcation. Moreover, the complicated homoclinic-doubling bifurcations are found and expressed approximately, and are well located. 展开更多
关键词 ORBIT FLIP INCLINATION Flips HOMOCLINIC ORBIT RESONANCE
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Resonant Homoclinic Bifurcations with Orbit Flips and Inclination Flips
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作者 Tiansi Zhang 《Applied Mathematics》 2013年第2期279-284,共6页
Homoclinic bifurcation with one orbit flip, two inclination flips and resonance in the tangent directions of homoclinic orbit is considered. By studying the associated successor functions constructed from a local acti... Homoclinic bifurcation with one orbit flip, two inclination flips and resonance in the tangent directions of homoclinic orbit is considered. By studying the associated successor functions constructed from a local active coordinate system, we prove the existence of double 1-periodic orbit, 1-homoclinic orbit, and also some coexistence conditions of 1-periodic orbit and 1-homoclinic orbit. 展开更多
关键词 ORBIT FLIP INCLINATION FLIP RESONANCE
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Numerical simulation study on spin resonant depolarization due to spin-orbit coupling
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作者 蓝杰钦 徐宏亮 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第8期295-301,共7页
The spin polarization phenomenon in lepton circular accelerators had been known for many years. It provides a new approach for physicists to study the spin feature of fundamental particles and the dynamics of spin-orb... The spin polarization phenomenon in lepton circular accelerators had been known for many years. It provides a new approach for physicists to study the spin feature of fundamental particles and the dynamics of spin-orbit coupling, such as spin resonances. We use numerical simulation to study the features of spin under the modulation of orbital motion in an electron storage ring. The various cases of depolarization due to spin-orbit coupling through an emitting photon and misalignment of magnets in the ring are discussed. 展开更多
关键词 spin polarization and resonant depolarization spin orbit coupling spin flip numericalsimulation
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Nonlocal Andreev reflection with Rashba spin-orbital interaction in a triple-quantum-dot ring
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作者 彭菊 郁华玲 左芬 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第12期489-494,共6页
We theoretically studied the nonlocal Andreev reflection with Rashba spin-orbital interaction in a triple-quantumdot (QD) ring, which is introduced as Rashba spin-orbital interaction to act locally on one component ... We theoretically studied the nonlocal Andreev reflection with Rashba spin-orbital interaction in a triple-quantumdot (QD) ring, which is introduced as Rashba spin-orbital interaction to act locally on one component quantum dot. It is found that the electronic current and spin current are sensitive to the systematic parameters. The interdot spin-flip term does not play a leading role in causing electronic and spin currents. Otherwise the spin precessing terra leads to shift of the peaks of the the spin-up and spin-down electronic currents in different directions and results in the spin current. Moreover, the spin-orbital interaction suppresses the nonlocal Andreev reflection, so we cannot obtain the pure spin current. 展开更多
关键词 aonlocal Andreev reflection Rashba spin-orbital interaction spin flip spin precess
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关于Guzowska-Luís-Elaydi模型的分岔(英文)
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作者 钟吉玉 《数学杂志》 CSCD 北大核心 2016年第3期465-473,共9页
本文考虑了一个离散的Logistic竞争模型。为了讨论分岔,给出了不动点的拓扑类型及非双曲的情况.应用中心流行约化定理,证明了跨临界分岔会在三个不动点上发生.本文还证明了在两个不动点处,跳跃分岔会发生,同时稳定的周期2轨会出现.
关键词 Logistic竞争模型 跨临界分岔 跳跃分岔 周期2轨 中心流行
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面向星地通信的低复杂度通用编译码技术 被引量:3
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作者 张可 林文超 王野 《中兴通讯技术》 北大核心 2024年第5期30-40,共11页
面向高动态、大尺度变化的低轨星地链路,具有强大纠错能力的速率兼容(RC)信道编码方案对保障星地时敏业务的信息时效性是至关重要的。提出了一种适用于任意短线性分组码的新型译码思想,称为基于翻转重量的阶序统计译码(FWB-OSD)。FWB-OS... 面向高动态、大尺度变化的低轨星地链路,具有强大纠错能力的速率兼容(RC)信道编码方案对保障星地时敏业务的信息时效性是至关重要的。提出了一种适用于任意短线性分组码的新型译码思想,称为基于翻转重量的阶序统计译码(FWB-OSD)。FWB-OSD可以达到比传统译码算法更优秀的误码性能水平。在此基础上,针对3GPP标准低密度奇偶校验(LDPC)码的速率兼容编码方案,提出了一种将迭代译码算法与FWB-OSD进行级联的译码算法,称为多层置信组合译码(MBCD)算法。相比于现有置信传播(BP)及级联译码算法,所提MBCD算法在短码长LDPC编码方案下能够展现更优的译码性能。最后,基于星地信道模拟器及相关前端信号处理方法,在桌面端开发了所提编译码方案在星地链路下的半实物验证系统。 展开更多
关键词 低轨星地链路 速率兼容信道编码 翻转重量辅助 多层置信 译码性能
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Spin flip in single quantum ring with Rashba spin–orbit interation
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作者 Duan-Yang Liu Jian-Bai Xia 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第3期397-400,共4页
We theoretically investigate spin transport in the elliptical ring and the circular ring with Rashba spin-orbit interaction. It is shown that when Rashba spin-orbit interaction is relatively weak, a single circular ri... We theoretically investigate spin transport in the elliptical ring and the circular ring with Rashba spin-orbit interaction. It is shown that when Rashba spin-orbit interaction is relatively weak, a single circular ring can not realize spin flip, however an elliptical ring may work as a spin-inverter at this time, and the influence of the defect of the geometry is not obvious. Howerver if a giant Rashba spin-orbit interaction strength has been obtained, a circular ring can work as a spin-inverter with a high stability. 展开更多
关键词 Rashba spin-orbit interaction quantum waveguide Aharonov-Bohm ring spin flip spin device
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具有轨道翻转和倾斜翻转的退化异维环分支 被引量:1
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作者 刘兴波 《中国科学:数学》 CSCD 北大核心 2013年第11期1113-1129,共17页
本文研究4维系统中一类具有轨道翻转和倾斜翻转的退化异维环分支问题.通过在未扰异维环的小管状邻域内建立局部活动坐标系,本文建立Poincar′e映射,确定分支方程.由对分支方程的分析,本文讨论在小扰动下,异宿环、同宿环和周期轨的存在... 本文研究4维系统中一类具有轨道翻转和倾斜翻转的退化异维环分支问题.通过在未扰异维环的小管状邻域内建立局部活动坐标系,本文建立Poincar′e映射,确定分支方程.由对分支方程的分析,本文讨论在小扰动下,异宿环、同宿环和周期轨的存在性、不存在性和共存性,且给出它们的分支曲面以及共存区域,推广了已有结果. 展开更多
关键词 局部活动坐标系 异维环 轨道翻转 倾斜翻转 POINCARE映射
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Homoclinic Bifurcation of Orbit Flip with Resonant Principal Eigenvalues 被引量:7
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作者 Tian Si ZHANG De Ming ZHU 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2006年第3期855-864,共10页
Codimension-3 bifurcations of an orbit-flip homoclinic orbit with resonant principal eigenvalues are studied for a four-dimensional system. The existence, number, co-existence and noncoexistence of 1-homoclinic orbit,... Codimension-3 bifurcations of an orbit-flip homoclinic orbit with resonant principal eigenvalues are studied for a four-dimensional system. The existence, number, co-existence and noncoexistence of 1-homoclinic orbit, 1-periodic orbit, 2n-homoclinic orbit and 2n-periodic orbit are obtained. The bifurcation surfaces and existence regions are also given. 展开更多
关键词 Orbit flip Homoclinic orbit Periodic orbit RESONANCE Principal eigenvalues
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Nongeneric Bifurcations Near a Nontransversal Heterodimensional Cycle 被引量:2
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作者 Xingbo LIU Xiaofei WANG Ting WANG 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2018年第1期111-128,共18页
In this paper bifurcations of heterodimensional cycles with highly degenerate conditions are studied in three dimensional vector fields,where a nontransversal intersection between the two-dimensional manifolds of the ... In this paper bifurcations of heterodimensional cycles with highly degenerate conditions are studied in three dimensional vector fields,where a nontransversal intersection between the two-dimensional manifolds of the saddle equilibria occurs.By setting up local moving frame systems in some tubular neighborhood of unperturbed heterodimensional cycles,the authors construct a Poincar′e return map under the nongeneric conditions and further obtain the bifurcation equations.By means of the bifurcation equations,the authors show that different bifurcation surfaces exhibit variety and complexity of the bifurcation of degenerate heterodimensional cycles.Moreover,an example is given to show the existence of a nontransversal heterodimensional cycle with one orbit flip in three dimensional system. 展开更多
关键词 Local moving frame Nontransversal heterodimensional cycle Orbit flip Poincare return map
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