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一种有非对称束形成区的高性能彩色CRT电子枪
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作者 Chen,H,Y 郁辉 《电子束器件》 1989年第28期45-49,44,共6页
关键词 彩色 CRT 电子枪 非对称束 形成区
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声学超表面的非对称声分束特性研究
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作者 宋爱玲 孙超彧 +2 位作者 陈天宁 项延训 轩福贞 《人工晶体学报》 CAS 北大核心 2021年第7期1362-1370,共9页
非对称声分束超表面是由人工微单元结构按照特定序列构建的二维平面结构,可将垂直入射的声波分成两束传播方向和分束比自由调控的透射波,在声功能器件设计及声通信领域具有广泛的应用前景。本文系统研究了一种实现非对称声分束的设计理... 非对称声分束超表面是由人工微单元结构按照特定序列构建的二维平面结构,可将垂直入射的声波分成两束传播方向和分束比自由调控的透射波,在声功能器件设计及声通信领域具有广泛的应用前景。本文系统研究了一种实现非对称声分束的设计理论和实现方法,基于局域声功率守恒条件研究了声分束器的设计理论、阻抗矩阵分布、法向声强分布、声压场分布等。利用遗传算法对四串联共振腔结构进行参数优化实现了声分束器所需的阻抗矩阵分布,声压场分布表明声波入射到声分束器后在入射侧激发出两列传播方向相反且幅值和衰减系数均相同的表面波,实现了入射侧与透射侧的局域声功率相互匹配。声波经过声分束器后被分为两束透射波,两束透射波的折射角和透射系数与理论值十分吻合,证明了设计理论及实现方法的正确性和可行性。本文的研究工作可以为新型非对称声分束结构设计提供理论参考、设计方法和技术支持,并促进其在工程领域的实际应用。 展开更多
关键词 非对称声分 声学超表面 局域声功率 阻抗矩阵 共振腔
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用形状双折射实现零耦合器声光开关偏振不敏感
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作者 吴磊 郑远 +1 位作者 濮宏图 陈树强 《半导体光电》 CAS CSCD 北大核心 2001年第5期327-330,共4页
对光纤型非对称束腰横截面耦合器进行了理论分析 ,并在实验上证明了耦合器的形状双折射随光纤的熔融程度从正到负的变化 ,最终可以达到偏振不敏感的目的。
关键词 零耦合器 非对称束腰横截面 偏振不敏感 声光开关
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非对称腹板束设计方法在地铁大跨变宽变高连续梁中的应用
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作者 曾一帆 《交通科技与管理》 2022年第8期81-83,共3页
文章以跨石清大道(46+60+40)m变宽变高连续梁为工程背景,研究了多种桥梁结构方案。因宽窄侧边跨结构特性差异较大,采用腹板通长束可能造成宽侧预应力不足或窄侧预应力冗余。该项目结合分段现浇施工,采用非对称腹板束设计方法,结构受力... 文章以跨石清大道(46+60+40)m变宽变高连续梁为工程背景,研究了多种桥梁结构方案。因宽窄侧边跨结构特性差异较大,采用腹板通长束可能造成宽侧预应力不足或窄侧预应力冗余。该项目结合分段现浇施工,采用非对称腹板束设计方法,结构受力及经济指标合理。目前该桥已运营一年有余,运营情况良好。研究成果可为类似轨道交通桥梁工程的设计和施工提供参考。 展开更多
关键词 变宽变高连续梁 非对称腹板 地铁桥梁
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Wavepacket Dynamics in a Non-Hermitian PT Symmetric Tight-Binding Chain 被引量:1
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作者 金亮 宋智 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第7期73-78,共6页
We examine the time development of a wavepacket in a Non-Hermitian PT symmetric tight-bindingchain based on the Bethe ansatz solutions.The complete orthogonal sets in both unbroken and broken PT symmetryregions are es... We examine the time development of a wavepacket in a Non-Hermitian PT symmetric tight-bindingchain based on the Bethe ansatz solutions.The complete orthogonal sets in both unbroken and broken PT symmetryregions are established with respect to an inner product in terms of CPT conjugation.The dynamical development ofa stationary wavepacket is exhibited,showing the impacts from additional imaginary potentials within unbroken andbroken symmetric regimes.Our result indicates that there are distinct dynamic characteristics for both two regions.Theunbroken symmetric imaginary end potentials can be regarded as a special kind of boundary condition in the sense ofHermitian quantum mechanics. 展开更多
关键词 NON-HERMITIAN PT symmetric CPT
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Lie-Form Invariance of a Type of Non-holonomic Singular Systems
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作者 WANG Jing LI Yuan-Cheng HOU Qi-Bao XIA Li-Li 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第3期409-412,共4页
In this paper, the Lie-form invariance of a type of non-holonomic singular systems is studied. The differential equations of motion of the systems are given. The definition and the criterions of the Lie-form invarianc... In this paper, the Lie-form invariance of a type of non-holonomic singular systems is studied. The differential equations of motion of the systems are given. The definition and the criterions of the Lie-form invariance for the systems are presented. The Hojman conserved quantity and the Mei conserved quantity are obtained. An example is given to illustrate the application of the results. 展开更多
关键词 non-holonomic constraint singular system SYMMETRY conserved quantity
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Unified Symmetry of Nonholonomic Mechanical Systems of Non-Chetaev's Type with Unilateral Constraints
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作者 XIA Li-Li LI Yuan-Cheng WANG Jing HOU Qi-Bao 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第6X期1081-1084,共4页
The definition and the criterion for a unified symmetry of nonholonomic mechanical systems of non- Chetaev's type with unilateral constraints are presented based on the total time derivative along the trajectory of t... The definition and the criterion for a unified symmetry of nonholonomic mechanical systems of non- Chetaev's type with unilateral constraints are presented based on the total time derivative along the trajectory of the system. A new conserved quantity, as well as the Noether conserved quantity and the Hojman conserved quantity, deduced froth the unified symmetry, is obtained. An example is given to illustrate the application of the results. 展开更多
关键词 unilateral constraints nonholonomic mechanical system of non-Chetaev's type unified symmetry conserved quantity
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Solution of an Inverse Eigenvalue Problem by Newton's Method on a Fibre Bundle with Structure Group SO(n)
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作者 Kwasi Baah Gyamfi Francis T. Oduro Anthony Y. Aidoo 《Journal of Mathematics and System Science》 2013年第3期131-135,共5页
We present a differential geometric perspective of the IEP for symmetric matrices in the framework of a fibre bundle with structure group SO(n). In particular, a Newton type algorithm is developed to construct a non... We present a differential geometric perspective of the IEP for symmetric matrices in the framework of a fibre bundle with structure group SO(n). In particular, a Newton type algorithm is developed to construct a non singular symmetric matrix for given target eigenvalues using a singular symmetric matrix as the initial matrix for the iteration. Explicit computations are performed for 2 x 2 non singular symmetric matrix to illustrate the result. 展开更多
关键词 Inverse eigenvalue problem MANIFOLD Lie group Lie algebra tangent bundle
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