交织型层级复杂网

为研究两个异质关联网络复合后的结构特征与节点中心性特征,本文提出了交织型层级复杂网络的概念,可描述由两个具有部分相同节点,连接边属性近似的子网所构成的层级复杂网络,并定义了节点交织系数、路径交织系数和网络交织系数3种测度用于衡量两个子网之间的密切程度.针对该类网络,研究并改进了节点度中心性和介数中心性的计算方法,同时提出一种新的中心性指标—助联性,用于衡量子网的某一节点对另一子网联通性和流通性的助益.通过实验分析,验证了本文各类指标的有效性.     

Stable anticipation synchronization in mutually coupled vertical-cavity surface-emitting lasers system

Two vertical-cavity surface-emitting lasers(VCSELs) are mutually coupled through a partially transparent mirror (PTM) placed in the pathway. The PTM plays the role of external mirror,which controls the feedback strength and coupling strength.We numerically simulate this system by establishing a visible SIMULINK model.The results demonstrate that the anticipation synchronization is achieved and it can tolerate some extent frequency detuning.Moreover,the system shows similar chaos-pass filtering effect on unidirectionally coupled system even both VCSELs are modulated.This system allows simultaneously bidirectional secure message transmission on public channels.     

石墨炉原子吸收光谱法测定硬聚氯乙烯饮水管中痕量锡

本文按标准GB／T10002．1－1996方法前处理样品,硝酸钙作基体改进剂,使锡的灰化温度提高并消除干扰。方法简便,快速,准确,灵敏度和精密度高,相对标准偏差为4．55％,回收率在90％－104％范围内。     

Magnetic behavior of the bond random mixed compound FE(BR x I1−x )2(x = 0.9) with Mössbauer spectroscopy

The bond random mixed compound Fe(Br_0.9I_0.1)₂ has been studied by magnetization and Mössbauer measurements. Although the zero-field cooled and field-cooled magnetization variations are not like a typical spin glass one, the Mössbauer spectrum below Néel temperature shows a hyperfine field distribution. It implies that the 10% FeI₂ mixed in FeBr₂ can be induced by the bond random effect which causes the sample to exhibit a spin glass-like behavior.     

Photoionization thresholds and structures of third group metals clustered with ammonia

A photoionization study of the Me(NH₃) clusters formed in the reaction of photoablated third group metal vapor with gaseous ammonia is reported. The photoionization spectra exhibit some features due to vibrational excitation of ionic clusters and to transitions to neutral Rydberg states leading to autoionization. DFT quantum chemical calculations are performed on the Me(NH₃). The cluster geometries are fully optimized imposing the C_3v symmetry. The calculated values of the IPs are in agreement with those experimentally determined. Received: 16 February 1998 / Revised and Accepted: 7 May 1998     

Symmetry properties and renormalization group in the stable superfluid phase of bosons at zero temperature

The appearence of divergences in perturbation theory for a system in a stable phase requires the existence of an underlying symmetry and related Ward identities to remove exactly these singularities in the physical response functions. In this paper we consider explicitly the Ward identities associated with the (gauge) symmetry of the interacting neutral Bose gas at zero temperature to solve the old-standing problem of infrared divergencies due to Bose- Einstein condensation. The exact infrared behavior of the system is achieved for any dimension d > 1. For 1 < d ? 3 the system is controlled by a non trivial line of fixed point distant from the Bogoliubov solution, while above d = 3 the Bogoliubov fixed point is found to be stable.     

A Construction of Multiresolution Analysis on Interval

We present a concrete method of constructing multiresolution analysis on interval. The method generalizes the corresponding results of Cohen, Daubechies and Vial [Appl. Comput. Harmonic Anal., 1（1993）, 54-81]. By the use of the subdivision operator, the expressions of the constructed functions are more compact. Furthermore, the method reveals more clearly some properties of multiresolution analysis with certain approximation order.     

Development and characterisation of an XeCl excimer laser-generated soft-X-ray plasma source and its applications

Summary A large-aperture, long-pulse XeCl excimer laser has been used to generate a soft-X-ray plasma source. Several laser optical configurations have been employed to optimise X-ray emission, including positive-branch unstable resonators and injection by seeding the gain region of the laser with a small commercial excimer laser, resulting in power densities in the range 10¹²–10¹⁴ W cm⁻². The characteristics of the plasma source for each different laser configuration and for different target materials are investigated. The most suitable source conditions (spectral energy distribution, time duration, etc.) for specific applications are discussed. Supported by the Royal Society, UK. Supported by INFM, Italy.     

VALUE-AT-RISK的核估计理论

如何根据历史数据估计Value-at-Risk（VaR）;是风险分析与管理中一个重要的基本问题.木文基于非参数核估计方法,通过拟合实际数据过程的分布,构造了VaR的估计.在合适的相依数据条件下,证明了该估计量的渐近正态性,并给出了渐近方差的估计.由此表明:本文所构造的估计量不仅比参数模型具有更广泛的适应性,而且如同参数模型具有n~（-1/2）的收敛速度.本文假设的数据过程避免使用混合性,可很好地适用于金融管理中广泛应用的ARMA与GARCH模型族及非线性模型.     

强流脉冲离子束辐照靶材烧蚀效应二维数值研究

对强流脉冲离子束(IPIB)辐照Ti靶的烧蚀效应进行了二维数值研究.得到了表面烧蚀物质随脉冲时间的变化关系.得出TEMP Ⅱ 型加速器产生的脉冲束流辐照靶材时引起的汽、液化均是从表面开始、并且汽化过程中表面物质被层层烧蚀的结论.同时，得到中心区的平均烧蚀速度为10m/s 数量级，它远小于产生的烧蚀等离子体的喷发速度.得到脉冲期间靶材内部不同位置烧蚀斑痕形状的时间演化过程，以及束流中含有的离子种类分额不同时IPIB辐照过程产生的不同效果. 关键词： 强流脉冲离子束 靶 烧蚀过程 二维数值模拟