Sine-Gordon模型的重整化与相变行为

采用高斯波泛函方法，讨论了连续场论和格点化场论的Ｓｉｎｅ－Ｇｏｒｄｏｎ模型的基态性质和相变现象，分析比较了两种不同重整化方法结果的异同。     

自对偶引力的局部对称性与约束

在Ashtekar形式下，广义相对论的相空间被嵌入到复SU（2）Yang-Mils理论的相空间里．将一般场论中分析局部对称性与约束的方法推广到复的场论，从自对偶Palatini形式的位形空间构造出Ashtekar形式的相空间，进而讨论了位形空间上的局部对称性与相空间上的约束的关系． 关键词：     

Krichever-Novikov弦的BRST量子化及拟自由弦场论

在Krichever-Novikov(简称KN)弦的BRST量子化的基础上,采用Siegel的方法构造了任意给定亏格的KN弦的拟自由场论,并提出了一种非微扰拟自由弦场论的尝试。 关键词：     

F－L模型的状态方程与退禁闭相变图象

用温度场论方法计算了Ｆ－Ｌ模型在有限温度和密度下的状态方程，分析了压强对净重子数密度的等温线．结果表明，在平均场近似下，Ｆ－Ｌ模型所给出的退禁闭相变为一级相变．     

有限温度QED中的轫致辐射修正

用有限温度场论方法,通过计算费曼图分析了在QED中由于温度效应导致的新红外发散.结果表明零温场论中的红外发散和由温度效应引起的红外发散可以用描写虚过程的费曼图同时消除.计算了轫致辐射中光子的辐射几率,在Eikonal近似下所得到的结果和半经典近似给出的结果一致.     

规范场论的发展和超对称性

对称性是宇宙间普遍存在的一种性质,在物理学中它表现为物理定律在某种对称变换下的不变性.现代物理学的两大支柱——量子力学和相对论的发展使这种对称性占有了特殊重要的地位. 最近二十多年里发展起来的规范场论便是以规范变换群下的不变性为特征来说明各种基本物理现象的理论.由于这一理论为描述各种基本自然力提供了一个适当的框架,自六十年代末期起,它在统一描述基本自然力的方面取得了重大进展,使爱因斯坦在晚期从事多年而未获得成功的统一场论研究在新的条件下重新获得了生命,因此很多人也把规范场论直接叫做统一场论.不过,规范场论…     

90年代理论物理学重大前沿课题系列报道（IV）

９０年代理论物理学重大前沿课题系列报道（ＩＶ）低维物理和场论方法研讨会简讯由国家科学技术委员会攀登计划重大项目“９０年代理论物理学重大前沿课题”和山西大学资助的低维物理和场论方法研讨会于１９９３年８月５日至１８日在山东省戚海市举行。１８名物理工作者参...     

根据介子场论探讨低速运动下的核力形式

本文仿效依万甯柯和苏科洛夫在“古典场论”一书中所给予的白莱脱作用推导法来推导低速运动下核子间的势能形式。这个方法可以应用到各种介子场和几种介子的混合场上去。所得结果很复杂,进一步的讨论尚待以后的工作。 一.核势能形式的推导 依万甯柯和苏科洛夫在“古典场论”一书中曾用古典方法导出两个电子间的白菜脱作用。其要略如下:按照通常的场论方法,运动方程可从以下作用函数的变分式导出:     

c＝3，N＝2超共形场论的Z2 0rbifold—Prime模型

讨论了二维环面上中心荷c＝3，N＝2的超共形场论。特别给出该理论的配分函数，进一步，为了产生新的模型，回顾了一般的orbifold方法，然后构造了模不变的Z2 0rbifold—Prime模型。     

Minkowski空间有限温度QCD的讨论

在Niemi和Semenoff提出的实时有限温度标量场论的基础上,将其推广到规范场的情形,使之适用于闵氏空间的有限温度QCD。利用本文引入的有限温度传播子,计算了高温QCD自由能的二圈修正,结果和Kapusta用欧氏空间场论方法得到的结果一致。 关键词：     

Aerial Video Trackers Review

Target tracking technology that is based on aerial videos is widely used in many fields; however, this technology has challenges, such as image jitter, target blur, high data dimensionality, and large changes in the target scale. In this paper, the research status of aerial video tracking and the characteristics, background complexity and tracking diversity of aerial video targets are summarized. Based on the findings, the key technologies that are related to tracking are elaborated according to the target type, number of targets and applicable scene system. The tracking algorithms are classified according to the type of target, and the target tracking algorithms that are based on deep learning are classified according to the network structure. Commonly used aerial photography datasets are described, and the accuracies of commonly used target tracking methods are evaluated in an aerial photography dataset, namely, UAV123, and a long-video dataset, namely, UAV20L. Potential problems are discussed, and possible future research directions and corresponding development trends in this field are analyzed and summarized.     

Parametric excitation of subharmonic oscillations

Subharmonic oscillations of order one-half for a single-degree-of-freedom system with quadratic, cubic, and quartic nonlinearities under parametric excitation are investigated. Two approximate methods (multiple scales and generalized synchronization) are used for comparison. The modulation equations (reduced equations) of the amplitudes and the phases are obtained. Steady-state solutions (periodic solutions) and their stability are determined. Numerical solutions are carried out, and graphical representations of the results are presented and discussed. The results obtained by the two methods are in excellent agreement.     

约束对Birkhoff系统Noether对称性和守恒量的影响

研究约束对Birkhoff系统的Noether对称性和守恒量的影响．首先，建立了Birkhoff系统的运动微分方程．其次，给出了系统Noether对称性的判据．然后，讨论了受约束作用后，Birkhoff系统的Noether对称性发生的变化，并给出了系统的Noether对称性以及守恒量保持不变的条件．最后，举例说明结果的应用． 关键词： 分析力学 Birkhoff系统 约束 Noether对称性 守恒量     

过渡金属原子掺杂的锯齿型磷烯纳米带的磁电子学特性

利用基于密度泛函理论的第一性原理方法,研究了掺杂铁、钴和镍原子的锯齿型磷烯纳米带(ZPNR)的磁电子学特性.研究表明,掺杂和未掺杂ZPNR的结构都是稳定的.当处于非磁态时,未掺杂和掺杂钴原子的ZPNR为半导体,而掺杂铁或者镍原子的ZPNR为金属.自旋极化计算表明,未掺杂和掺杂钴原子的ZPNR无磁性,而掺杂铁或者镍原子的ZPNR有磁性,但只能表现出铁磁性.处于铁磁态时,掺杂铁原子的ZPNR为磁性半导体,而掺杂镍原子的ZPNR为磁性半金属.掺杂铁或者镍原子的ZPNR的磁性主要由杂质原子贡献,产生磁性的原因则是在ZPNR中存在未配对电子.掺杂位置对ZPNR的磁电子学特性有一定的影响.该研究对于发展基于磷烯纳米带的纳米电子器件具有重要意义.     

亲水性材料固相萃取-紫外导数光谱法检测血中茚满二酮灯抗凝 …

本文报导了血中茚满二酮类抗凝血杀鼠剂敌鼠、氯敌鼠、杀鼠酮的亲水性材料固相萃取－紫外导数光谱检测法。血样用pＨ５缓冲液等体积稀释后加于西雷脱硅藻土柱上,柱用乙酸乙 酯洗脱,将洗脱液挥发干净,剩余物用pＨ１０缓冲液溶解,测定所得溶液的二阶导数光谱进行定性和定量分析。三种杀鼠剂以１０mg／Ｌ的量加于空白血中测得萃取率为８５％以上,血中三种杀鼠剂的检出限低于２ｍｇ／Ｌ。萃取中亲水性硅藻土可用硅胶和氧化铝代替,     

便携式近红外光谱仪器现状及展望

近红外光谱分析技术具有速度快、操作简单等优点,在农业、制药等行业得到了大量应用,其中一些应用需要将仪器携带到分散的分析现场使用,为满足这一需求,很多体积小、便于移动的便携式近红外光谱仪被研制出来。这些仪器的种类较为繁多,采用了很多不同的基本原理,使用了不同的光路结构。文章综述了国内外便携式近红外光谱仪的技术现状,根据光路结构的不同将仪器分成滤光片型、光栅型、傅里叶变换型、声光可调滤波器型以及使用微机电系统(MEMS)的新型光谱仪等类型,重点介绍各类仪器的原理和主要部分的结构,同时简要介绍不同类型仪器的特点,并列举典型产品。也对测量附件、操作、显示等外围部分的设计作简要介绍,这些附件针对便携应用采取了特殊的设计。通过介绍,为新型便携式近红外光谱仪的研制提供借鉴。最后,对便携式近红外光谱仪器的现状作总结,并对未来国内外技术的发展进行展望。     

毛细芯热管蒸汽流动特性研究

热管内蒸发和凝结时工质会径向迁移,导致蒸汽流动特性与管流有很大不同。对热管内蒸汽流动的速度分布和压降特性进行了分析,比较了现有热管蒸汽压降的计算方法。同时考虑蒸汽流动时黏性力和惯性力的作用,提出了计算蒸汽流动速度和压降的改进方法,消除了前人方法应用范围的限制。利用此计算方法,蒸汽速度分布随径向雷诺数变化较大。与钠热管的数值模拟结果对比表明,此计算方法应用范围广,准确度较高。     

Ablation of Transparent Materials Using Excimer Lasers for Photonic Applications

For many years, the development of effective ablation or laser machining techniques for making micro-optical components has been the key factor in the birth of new photonic devices and systems. In this article, the ablation characteristics of two types of the most important transparent materials, transparent polymers and glasses, are studied. Simple shaped microcavities are first machined for studying the fundamental ablation parameters, including threshold fluence, effective absorption coefficient, and ablation rate. In studying polymer ablation, five standard grades and five proprietary polymeric compounds are selected. Ablation techniques using these transparent polymers for making arrayed ferrules and curved microlenses are presented. Applications of these ablated microstructures for optical fiber connectors, optical fiber coupling and alignment, and transparent chip encapsulants, are introduced and demonstrated with emphasis on the quality of the ablated profiles and dimensions to satisfy the required performance. In glass ablation, borosilicate glasses are considered and their associated ablation behaviors are studied. The procedures to ablate glass-based arrayed microstructures with flat and curved surfaces are described. The utilizations of these arrayed microstructures for optical waveguide, wave absorber, and beam guider, are specifically discussed. Finally, concluding remakes for future trends are presented.     

Semiclassical elementary particle models

Some simple models of elementary particles are discussed; they may be described as semiclassical, quark, shell models. Particles are assumed to be composed of spherical concentric charged shells. Three basic types of shell are allowed, quantum numbers are associated with each type such as to establish a quantum number correspondence between the shell types and the (p, n, ) quarks. Particles are identified through the quantum numbers of their constituent shells (quarks).The basic assumptions underlying the models considered are relationships between the electromagnetic energy associated with elementary particles (quark systems) and particle masses. The electromagnetic energy is represented classically; the models are semiclassical in that the shell radii are related to particle Compton wavelengths.Particle mass and magnetic moment formulas are derived, possible values for quark masses are suggested, and possible connections of the models considered with particle symmetry schemes are discussed.