Vanishing torsion of parametric curves

We consider the class of parametric curves that can be represented by combination of control points and basis func- tions. A control point is let vary while the rest is held fixed. It’s shown that the locus of the moving control point that yields points of zero torsion is the osculating plane of the corresponding discriminant curve at its point of the same parameter value. The special case is studied when the basis functions sum to one.     

借助MATLAB软件理解初等复变函数

复变函数由实部和虚部两个二元函数组成,其图形需要在四维空间中显示,与二元实变函数相比,复变函数相对不容易理解,并且一些复变函数有着与实变函数截然不同的特征。借助MATLAB软件将复变函数可视化,使抽象问题具体化、直观化,从而加深学生对复变函数特征的理解。     

Effect of heat-treatment on LiZn ferrite hollow microspheres prepared by self-reactive quenching technology

Lithium-zinc ferrite hollow microspheres (LiZn FHMs) containing special surface crystals were synthesized by self-reactive quenching technology. The samples were heat-treated at 1200 °C and held for 4 h. The influence of the heat-treatment on LiZn FHMs was studied. The results show that the surface of hollow microspheres is smooth without heat-treatment. The phase components are Fe₂O₃, Fe₃O₄, Li_0.435Zn_0.195Fe_2.37O₄, and Li_0.5Fe_2.5O₄. The minimum reflectivity is ?13.5 dB, and the corresponding frequency is 7.5 GHz. The effective absorption band lower than ?10 dB is 6.2–8.5 GHz, and the bandwidth is 2.3 GHz. After heat-treatment, crystals on the surface of hollow microspheres grow significantly. Multiple-shape micro-nano crystals containing triangular, polygonal, and irregular crystal are generated. However, the phase composition does not change. The real part of the permittivity (ε′), the imaginary part of permittivity (ε″), the real part of permeability (μ′), and the imaginary part of permeability (μ″) all increase, and the microwave absorption properties at low frequency are significantly increased, with the absorption peak moving to a lower frequency range. The minimum reflectivity is ?26.5 dB, and the corresponding frequency changes to 3.4 GHz. The effective absorption band is 2.6–4 GHz, and the bandwidth is 1.4 GHz.     

C.-R.方程的推广及其应用

利用多元函数方向导数的概念与矩阵变换等方法推广了C.-R.方程,给出了解析函数f（z）=u（x,y）＋iv（x,y）的实部与虚部关于任意两个方向v1,v2的方向导数（偏du/偏dv1,偏dv/偏dv1）与（偏du/偏dv2,偏dv/偏dv2）之间的关系.利用所得结果对复变函数可微的一个充要条件做了改进.相应的结论对解析函数也成立.     

具有复介电常量对称结构一维三元光子晶体透射谱的研究

利用传输矩阵法理论,研究含复介电常量对称结构一维三元光子晶体的光传输特性。结果表明:当各层介质的介电常量均为实数时,在较宽的禁带范围内出现一条透射率为100%的透射峰;当介质介电常量含正虚部时,禁带中的透射峰出现透射衰减现象,若含有负虚部时,透射峰则出现透射增益现象;随着复介电正虚部的增大,透射峰出现单调衰减,而随着复介电负虚部绝对值的增大,透射增益达到一极大值,随后减小;在不同介质层引入复介电常量引起透射峰的透射率衰减或增益强度不同。这些特性对设计光放大器、衰减器等新型光学器件有一定的参考价值。     

关于Krein空间上J-正常算子可定化性的一个注记

利用可定化J-自伴算子的谱函数,对于Krein空间上J-正常算子N的可定化性与其实部、虚部的可定化性之间的关系做了讨论.指出若N的实部或虚部中有一个为可定化算子（强可定化算子、一致可定化算子）,则N是可定化的（强可定化的、一致可定化的）,且通过例子说明该结论的逆命题并不成立.     

具有复介电常量一维光子晶体的特性研究

借助传输矩阵法,数值模拟了具有实介电常量和复介电常量一维光子晶体的带隙结构,发现具有复介电常量一维光子晶体的带隙出现增益,并对此作出了Imεα-R,Imεα-λ的关系曲线．这对研究和设计二、三维光子晶体具有一定的指导意义．     

高斯整数环上矩阵的平方和表示

本文主要研究可表示成高斯整数矩阵的平方和的高斯整数矩阵能表示高斯整数矩阵的平方和的个数,得出了     

关于高校后勤企业文化的诌议

企业文化是一种新的管理理论,在现代企业建设中有着极其重要的功用。具体到高校后勤企业来讲,如何界定高校后勤企业文化?高校后勤企业应建设一种什么样的企业文化?文章从校园亚文化角度初步阐述了高校后勤企业文化的内涵和应具备的育人、导向、激励等基本功能。     

关于残数定理的一些应用

残数定理是复变函数论中的基本理论，它有着十分重要的应用。本文阐述了残数定理在计算定积分，广义积分，级数求和等方面的应用。     

一维无限深势阱的辛算法解分析

利用辛算法计算一维无限深势阱的含时薛定谔方程，解得的波函数的图象与其绝时误差的图象完全相似，这说明各点的相时误差趋向于一个固定值。经计算相时误差在各个X格点处完全相同。波函数相时误差随时间的演变表现出一定的规律性，其实数部分和虚数部分的相时误差周期性地在正负之间来回变化。波函数的实数部分和虚数部分的相时误盖之间有类似于测不准原理的关系，一个相时误差趋向于极小时另一个相时误差趋向于极大，两的乘积为一稳定的小数，随着时间的推进这一小数的绝时值缓慢增大。     

拉格朗日微分中值定理在复变函数论中的推广

给出了拉格朗日微分中值定理在解析区域D内整体性推广、向实部和虚部上的推广。     

“TM”入射情况含双缝平面导体电磁散射特性研究

研究由横磁场(TM)激励含两个孔缝的无限平面导体的散射特性．孔缝另一端构成一微波网络．我们用基于格林函数的矩量法计算这一问题．用波导模函数展开未知函数，采用伽略金法和三角形基函数．给出了扩展的归一化网络参数．由一平面波激发，通过求解归一化网络参数和散射场的场强模式计算，给出几组不同参数情况下的散射圃图和数值结果．一些计算实例可以和“TE”情况进行比较．我们认为在导体内部微波网络和两孔缝是互相连通的．     

浅析房地产广告策略——Soho沸城广告策略个案研究

Soho沸城房地产广告改写了成都房地产销售周期的历史记录,该广告主要采用平面广告,整体画面以红色为基调,视觉冲击力大,概念简洁,设计唯美。在策略上,通过广告宣传加大促销力度,启动多种宣传媒介以全面覆盖目标消费群,宣传量达到一定的饱和度,努力塑造品牌形象,获得了极大的成功,提升了国内房地产的品牌形象。     

Preschool Children's Symbolic Representation of Objects through Gestures

To investigate the symbolic quality of preschoolers' gestural representations in the absence of real objects, 48 children (16 3-, 4-, and 5-year-olds) performed 2 tasks. In the first task, they were asked to pretend to use 8 common objects (e.g., "pretend to brush your teeth with a toothbrush"). There was an age-related progression in the symbolic quality of gestural representations. 3- and 4-year-olds used mostly body part gestures (e.g., using an extended finger as the toothbrush), whereas 5-year-olds used imaginary object gestures (e.g., pretending to hold an imaginary toothbrush). To determine if children's symbolic skill is sufficiently flexible to allow them to use gestures other than those spontaneously produced in the first task, in the second task children were asked to imitate, for each object, a gesture modeled by an experimenter. The modeled gesture was different from the one the child performed on the first task (e.g., if the child used a body part gesture to represent a particular object, the experimenter modeled an imaginary object gesture for that object). Ability to imitate modeled gestures was positively related to age but was also influenced by the symbolic mode of gesture. 3-year-olds could not imitate imaginary object gestures as well as body part gestures, suggesting that young preschoolers have difficulty performing symbolic acts that exceed their symbolic level even when the acts are modeled. Results from both tasks provide strong evidence for a developmental progression from concrete body part to more abstract imaginary object gestural representations during the preschool years.     

排列函数和组合函数的性质与应用

引入了排列函数与组合函数,推广了排列数与组合数的概念,获得了排列函数与组合函数的若干性质,得到了广义组合(或排列)数与普通组合(或排列)数的关系式.依据推广的二项式级数获得了一批新的组合恒等式.推导出了关于排列函数、组合函数的线性表示式、表示式系数的递推关系式和系数新公式,获得了等幂和的四个表示公式.     

Three Routes to Chaos in Electrical Power Systems

Study on power systemchaotic phenomena is oneimportant aspect in power system stability stu-dies[1—3]. Early studies, such as Lee[4], Chiang[5],Wang[6]and Tan[7], mainly focused on interpretingthe behavior of chaotic oscillations. Later researches,such as Wu[8], Rajesh[9], Jia[10,11], Srivastava[12]and Abed[13]began to concern the following topics,such as interaction of chaotic motion and system dy-namics, the relationship of power system stability re-gion and chaos, and the methods to eli…     

主体地位的缺失与回归--对教育主体地位确立的一个思考

相对于教育本身而言，教师与学生共同扮演了教育中的弱势群体角色。这一主体地位的缺失，如果说在以应试教育为代表的传统的教育体系中还能得以默认的话，那么，在以素质教育为代表的现代教育体系中，这一现象就不容再存在了。素质教育从根本上不仅要求突出学生在教育中的主体地位，同时也要求突出教师在教育中的主体地位，只有将二者的主体地位同时确立，才是真正意义上的教育主体地位的确立。     

论全平面Hilbert型积分不等式及其算子刻画

引入独立参量,应用权函数的方法及实分析技巧,建立一个具有最佳常数因子的全平面非齐次核Hilbert型积分不等式,考虑了其等价式、逆式及相关的齐次式与Hardy型不等式;定义了全平面Hilbert型积分算子,还求出了一些特殊核的算子范数.     

Morphological processing during visual word recognition in Hebrew as a first and a second language

The present study examined whether sublexical morphological processing takes place during visual word-recognition in Hebrew, and whether morphological decomposition of written words depends on lexical activation of the complete word. Furthermore, it examined whether morphological processing is similar when reading Hebrew as a first language (L1) or as a second language (L2), and whether L1’s morphological background, Semitic or Indo-European, modulates morphological processing in L2 Hebrew (a Semitic language), among proficient readers. To reveal the sublexical processing of the Hebrew morphemes, the Root (R) and the Pattern (P), a lexical-decision task was conducted, in which all critical stimuli were non-word letter-strings manipulated to include or exclude real Hebrew morphemes. Different combinations of real (+) and pseudo (?) morphemes yielded four types of non-words (+R+P; +R?P; ?R+P, ?R?P). Three groups of proficient Hebrew readers were tested: L1 Hebrew, L1 English-L2 Hebrew, and L1 Arabic-L2 Hebrew. Results demonstrated significant differences in latency and accuracy of responses to the four morphological conditions, indicating that sublexical morphological processing occurs during visual word-recognition of morphologically structured letter-strings in Hebrew. Importantly, the activation of real Hebrew morphemes occurred in non-word stimuli, indicating that morphological processing in Hebrew is separable from lexical activation. Moreover, the same pattern of results was observed in all three L1 groups, indicating that proficient L2 readers exhibit morphological processing strategies that are tuned to the L2 morphology, regardless of their L1 background.