相干光纤传象束串象性质分析

本文报道了关于相干柔软光纤传象束(FIB)串象特性的研究.提出一种采用定标的光学视频系统定量测量相干柔软光纤传象束串象率的新方法.在光纤传象束的输入端,借助高精度的光学耦合系统,使光线仅对单根光纤输入耦合,而在传象束的输出端,由CCD阵列相机对被激光纤作大面积范围的检测.并且,测量了光纤传象束的静态调制传函数(MTF),用于描述串象率对传象束传象特性的影响,比较了多种传象束样品的测量结果.     

A simple method to prepare miniature quartz fiber boats with superhydrophobicity

According to the reformed Cassie-Baxter equation, a superhydrophobic quartz fiber bundle boat was fabricated from mimicking the lotus leaf venation using chemical surface modifications and roughness introductions. Water contact angles as high as 165.8° were achieved for quartz fiber cloths. The loading capacities of the miniature boats made from the superhydrophobic quartz fiber bundles were measured. The highest loading weight, 10.19 g, was obtained by the boats with 2.0 mm spacing distance between fiber bundles. The striking loading capacities were believed to stem from the air film surrounding the superhydrophobic surfaces of the boats. The results of this study presented new applications of artificial hydrophobic surfaces in areas of aquatic devices.     

基于多导体传输线理论的差模激励新型线束串扰模型研究

传统的线束串扰模型只是在系统内共模激励的基础上建立的, 没有考虑系统间差模激励下线束串扰的情况. 针对差模激励下系统独立回路间线束串扰的物理问题, 提出了一种基于多导体传输线理论的差模激励新型线束串扰的计算方法.该方法根据差模激励下线间的耦合机理, 利用传输线传播横向电磁模式得到新型三导体传输线寄生参数电路及数学矩阵模型, 通过镜像法以及诺埃曼公式推导出寄生参数的计算公式, 并在频域内得到新型线束串扰的链参数矩阵方程, 根据新型差模串扰模型始端、终端边界条件最终得到串扰电压的频域解.以差模激励下平行双线回路对其他回路受扰线的串扰为例, 通过仿真受扰线不同布置情况下的串扰电压, 得到了差模激励源的线束间串扰的物理规律, 即受扰线位于差模回路之间时所受的串扰要远大于位于回路外时所受的串扰, 并验证所提出的模型及方法可以计算不同频率差模激励引起的干扰. 利用解析的方法解决了线束串扰中差模激励下的导线串扰问题, 为实际中如大量导线的捆扎以及导线干扰的预测等电磁兼容问题提供了理论依据, 具有指导意义, 完善了多导体传输线理论在线束串扰中的应用.     

序排列光纤传像束光特性的测量研究

目前，柔软光纤显微镜已广泛应用于工业，医学等领域，光纤显微镜的光学特性，取决于其核心元件“光纤传像束”的光不质量。迄今为止，有关这方面的研究尚未完善，据此，本文报道了我们最新的关于序排列柔软光纤传像束光特性的理论分析和实验研究结果。     

Non-holonomic and semi-holonomic frames in terms of Stiefel and Grassmann tangent bundles

We prove that the bundles of non-holonomic and semi-holonomic second-order frames of a real or complex manifold M can be obtained as extensions of the bundle F²(M) of second-order jets of (holomorphic) diffeomorphisms of into M, where or . If and is the bundle of -linear frames of M we will associate to the tangent bundle two new bundles and with fibers of type the Stiefel manifold and the Grassmann manifold , respectively, where . The natural projection of onto defines a -principal bundle. We have found that the subset of given by the horizontal n-planes is an open sub-bundle isomorphic to the bundle of semi-holonomic frames of second-order of M. Analogously, the subset of given by the horizontal n-bases is an open sub-bundle which is isomorphic to the bundle of non-holonomic frames of second-order of M. Moreover the restriction of the former projection still defines a -principal bundle. Since a linear connection is a horizontal distribution of n-planes invariant under the action of it therefore determines a -reduction of the bundle , in a bijective way. This is a new proof of a theorem of Libermann.     

单纤光纤探针测量空泡份额的实验研究

1前言气（汽）液两相流广泛应用于工业过程中。空泡份额是气（汽）液两相流的重要参数，它与流场、压力、热流密度和流型等密切相关。由于目前的理论计算模型还有较大的局限性，因此实验测量是研究气（汽）液两相流空泡份额的最主要的研究手段。经过近几十年的研究，各国学者开发出了许多有价值的空泡份额测量方法，其中包括平均空泡份额测量方法和局部空泡份额测量方法，这些测量方法本身各有各的局限性和一定的针对性。本文研究水平管束间汽液两相流流动和沸腾传热特性，流道中加热管柬的存在对流体流动产生强烈的影响，使管束间汽液两相…     

Coherent state map quantization in a Hermitian-like setting

For vector bundles having an involution on the base space, Hermitian-like structures are defined in terms of such an involution. We prove a universality theorem for suitable self-involutive reproducing kernels on Hermitian-like vector bundles. This result relies on pullback operations involving the tautological bundle on the Grassmann manifold of a Hilbert space and exhibits the aforementioned reproducing kernels as pullbacks of universal reproducing kernels that live on the Hermitian-like tautological bundle. To this end we use a certain type of classifying morphisms, which are geometric versions of the coherent state maps from quantum theory. As a consequence of that theorem, we obtain some differential geometric properties of these reproducing kernels in this setting.     

Preparation of superhydrophobic poly-p-phenylenebenzobisoxazole (PBO) fiber bundles

According to the reformed Cassie-Baxter equation, the superhydrophobic phenylenebenzobisoxazole (PBO) fiber bundle boats were fabricated from mimicking the lotus leaf venation using chemical surface modifications and roughness introduction. Water contact angles as high as 152.3° were achieved for PBO fiber bundles. Furthermore, the loading capacities of the superhydrophobic PBO fiber bundle boats were also measured. And the highest loading weight, 8.36 g, was obtained by the boats treated with 2.0 wt.% (heptadecafluoro-1,1,2,2,-tetradecyl)trimethoxysilane (HFTES). The large loading capacities were believed to arise from the air film surrounding the superhydrophobic surfaces of boats. The results of this study presented new applications of artificial hydrophobic surfaces in areas of miniature aquatic devices.     

Energy bands: Chern numbers and symmetry

Energy bands formed by rotation–vibrational states of molecules in the presence of symmetry and their qualitative modifications under variation of some control parameters are studied within the semi-quantum model. Rotational variables are treated as classical whereas a finite set of vibrational states is considered as quantum. In the two-state approximation the system is described in terms of a fiber bundle with the base space being a two-dimensional sphere, the classical phase space for rotational variables. Generically this rank 2 complex vector bundle can be decomposed into two complex line bundles characterized by a topological invariant, the first Chern class. A general method of explicit calculation of Chern classes and of their possible modifications under variation of control parameters in the presence of symmetry is suggested. The construction of iso-Chern diagrams which split the space of control parameters into connected domains with fixed Chern numbers is suggested. A detailed analysis of the rovibrational model Hamiltonian for a D₃ invariant molecule possessing two vibrational states transforming according to the two-dimensional irreducible representation is done to illustrate non-trivial restrictions imposed by symmetry on possible values of Chern classes.     

The Einstein evolution equations as a first-order quasi-linear symmetric hyperbolic system,I

A systematic presentation of the quasi-linear first order symmetric hyperbolic systems of Friedrichs is presented. A number of sharp regularity and smoothness properties of the solutions are obtained. The present paper is devoted to the case ofR ⁿ with suitable asymptotic conditions imposed. As an example, we apply this theory to give new proofs of the existence and uniqueness theorems for the Einstein equations in general relativity, due to Choquet-Bruhat and Lichnerowicz. These new proofs usingfirst order techniques are considerably simplier than the classical proofs based onsecond order techniques. Our existence results are as sharp as had been previously known, and our uniqueness results improve by one degree of differentiability those previously existing in the literature.Partially supported by AEC Contract AT(04-3)-34.Partially Supported by NSF Contract GP-8257.     

Generalized holomorphic structures

We define the notion of generalized holomorphic principal bundles and establish that their associated vector bundles of holomorphic representations are generalized holomorphic vector bundles defined by M. Gualtieri. Motivated by our definition, several examples of generalized holomorphic structures are constructed. A reduction theorem of generalized holomorphic structures is also included.     

棒束通道CHF预测方法研究

本文采用实验和数值计算分析相结合的方法,研究了带定位格架棒束通道内过冷流动沸腾工况下临界热流密度(CHF)发生情况.提出了通过采用CFX4.4程序对带定位格架棒束通道内过冷流动沸腾计算来预测CHF发生位置的方法.结果表明,随着程序的发展和物理模型的完善,计算流体动力学方法(CFD)将成为核燃料棒束组件临界热流密度实验、设计和安全评估强有力的计算分析工具.     

线束干扰响应的精简计算模型

将电缆束等效方法与传统的传输线方法相结合,提出了多芯电缆束的精简SPICE分析模型。首先采用有限元法求解等效电缆束的模型参数,然后在SPICE环境中进行时域分析。以14芯电缆束的串扰问题和4芯电缆束的辐射干扰问题为例,对精简分析模型的有效性进行了验证。全模型与精简模型分析结果表明,精简模型线缆芯线数减少了一半以上,仿真幅度误差在5%以内,分析效率提高50%以上。该方法适用于大线束传导耦合分析、串扰分析和辐射分析。     

固体单相催化剂CVD法制备成束或分散MWCNT*

CVD法制备纳米碳管的催化剂多是以Al2 O3、SiO2 或MgO作载体 ,Fe、Ni或Co等过渡族金属为活性组分[1- 3] .催化剂与载体之间的关系存在多种形式[1] ,其中固溶体催化剂[4 ,5] 使过渡金属离子能均匀地分布在载体的内部和表面 .在后续反应过程中 ,均匀分布在表面或体内的金属离子被还原成具有催化活性的金属微粒 .此法称为“原位催化分解法 (insituCVD法 )” ,常用于制备直径分布较为均匀的纳米碳管 ,但以往的这些固溶体催化剂在制备纳米碳管的产量上并没有明显的改善 .本工作报道用燃烧法制备的Fe Mo Mg O固溶体 ,不但在用于CVD法生长…     

A proof of the Nielsen-Ninomiya theorem

The Nielsen-Ninomiya theorem asserts the impossibility of constructing lattice models of non-selfinteracting chiral fermions. A new proof is given here. This proof fills a technical gap in the two proofs presented by the authors of the theorem. It also serves as prelude to an investigation of the chiral properties of the general lattice model.     

规范场理论和金融市场模型

文章介绍近年理论物理在金融学市场建模中的应用的一个新方向，与一般的数学建模不同，它是应用几何结构的模型，建立在规范场的物理思想和纤维丛的几何结构的基础上，文章介绍了规范场的物理概念思想原则，也介绍纤维丛数学概念和几何结构，然后说明规范场理论与纤维丛理论的相结合，成为与金融市场概念和运作相匹配的市场模型，举出这一模型成功引导出金融市场产品定价的Black—Scholes方程和公式。文章对象以物理学者为主，对于理论经济学、金融理论和系统科学的读者来说可略去数学推导。     

Application of Connection in Molecular Dynamics

The evolution of electronic states in molecule has two origins: dynamical one produced by Schr¨odinger equation and kinematical one caused by base transformation due to nuclear motion.In current theories,the former gets analytic expression; the latter depends on heavy numerical calculation,which contains uncertainty.By using connection of fiber bundles,this paper establishes an analytic formula for the latter,and the numerical work is simplified.It shows the mathematical structure of molecule is fiber bundle.     

Comment on: Ising models on hyperbolic graphs

New proofs are given for Propositions 1 and 2 of C. C. Wu,J. Stat. Phys. 50:251 (1996). The propositions involved upper and lower bounds on the critical temperature for these models. Besides being more direct than the previous proofs, the new proofs improve both bounds.