Generalized chaos synchronization of a weighted complex network with different nodes

This paper proposes a method of realizing generalized chaos synchronization of a weighted complex network with different nodes. Chaotic systems with diverse structures are taken as the nodes of the complex dynamical network, the nonlinear terms of the systems are taken as coupling functions, and the relations among the nodes are built through weighted connections. The structure of the coupling functions between the connected nodes is obtained based on Lyapunov stability theory. A complex network with nodes of Lorenz system, Coullet system, Rõssler system and the New system is taken as an example for simulation study and the results show that generalized chaos synchronization exists in the whole weighted complex network with different nodes when the coupling strength among the nodes is given with any weight value. The method can be used in realizing generalized chaos synchronization of a weighted complex network with different nodes. Furthermore, both the weight value of the coupling strength among the nodes and the number of the nodes have no effect on the stability of synchronization in the whole complex network.     

Optical properties of Mg~(2+),Yb~(3+),and Ho~(3+) tri-doped LiNbO_3 crystals

A series of LiNbO_3 crystals tri-doped with Mg~(2+),Yb~(3+),and Ho~(3+) are grown by the conventional Czochraski technique.The concentrations of Mg~(2+),Yb~(3+),and Ho~(3+) ions in Mg:Yb:Ho:LiNbO_3 crystals are measured by using an inductively coupled plasma atomic emission spectrometry.The x-ray diffraction is proposed to determine the lattice constant and analyze the internal structure of the crystal.The light-induced scattering of Mg:Yb:Ho:LiNbO_3 crystal is quantitatively described via the threshold effect of incident exposure energy flux.The exposure energy(E_r) is calculated to discuss the optical damage resistance ability.The exposure energy of Mg(7 mol):Yb:Ho:LiNbO3 crystal is 709.17 J/cm~2,approximately 425 times higher than that of the Mg(l mol):Yb:Ho:LiNbO_3 crystal in magnitude.The blue,red,and very intense green bands of Mg:Yb:Ho:LiNbO_3 crystal are observed under the 980-nm laser excitation to evaluate the up-conversion emission properties.The dependence of the emission intensity on pumping power indicates that the up-conversion emission is a two-photon process.The up-conversion emission mechanism is discussed in detail.This study indicates that Mg:Yb:Ho:LiNbO_3 crystal can be applied to the fabrication of new multifunctional photoluminescence devices.     

六硼化铕亚微米管的电子场发射性能(英文)

以铕(Eu)粉末和三氯化硼(BCl3)作为前驱体,用简单的化学气相沉积方法制备了六硼化铕(EuB6)亚微米管。用XRD,SEM拉曼光谱,和TEM来表征EuB6微米管的形貌和晶体结构。场发射测试结果表明:根据F-N公式,场发射电流和电场之间在不同的阶段分别满足直线关系。     

美国大学先修(AP)物理课程分析

大学先修物理课程是美国的大学先修(AP)课程中的重要组成部分,课程由AP物理1、AP物理2、AP物理C-力学和AP物理C-电磁学4门子课程组成。本文基于现行的AP物理课程大纲,解读其课程理念和知识框架,并结合其评价考核方式分析AP物理课程体系的优点,以期对国内大学物理先修课程的建设予以启示。本文还以附录的形式给出一道AP物理C-电磁学原题。     

正色散激光器中的增益导引孤子

采用非线性薛定谔方程模拟了全正色散介质激光器中实现脉冲锁模输出的动态过程,理论表明,不同于工作于净色散为负的孤子锁模激光器以及腔内具有色散延迟线净色散为正的色散管理孤子和自相似脉冲锁模激光器,在纯正色散介质构成的锁模激光器中,增益饱和和增益窄化对形成稳定的锁模脉冲起重要的作用,在两者的作用下脉冲形成增益导引孤子.采用不同的锁模方式在纯正色散光纤锁模激光器中得到了稳定的增益导引孤子锁模,实验结果与理论模拟一致. 关键词： 锁模 正色散 增益导引孤子     

TEA CO2激光器序列带的输出特性

 采用双光栅谐振腔和增长放电增益区,进行了TEA CO₂激光器弱线输出特性研究。在CO₂,N₂,He气体体积比为0.16∶0.21∶0.63,总压强为57.3 kPa情况下,获得6条11 μm波长附近弱线(序列带和热带)激光输出,谱线脉宽为400 ns左右。研究了011-030带的P19线的输出波形和能量,结果表明：谱线输出能量随光栅中心的位移变化而变化,当光栅中心在放电区中心轴线上时输出最强,最大输出能量达几百mJ。     

槲皮素-锡(Ⅳ) 荧光光度法的研究及其应用

研究了槲皮素－锡（Ⅳ）荧光体系的形成条件,建立了测定了槲皮素的荧光度法。在０．００８ｍｏｌ／ＬＨＣｌ介质中,形成ｎ（槲皮素）：ｎ「锡（Ⅳ）」＝２：１的荧光络合物。ＴｒｉｔｏｎＸ－１００对体系有强烈的增敏作用,激发波长为４４３ｎｍ。发射波长为４９５ｎｍ。     

HfO2／SiO2高反射膜的缺陷及其激光损伤

用原子力、Normaski和扫描电子显微镜等分析仪器,对高损伤阈值薄膜常采用HfO2/SiO2薄膜进行了表面显微图象研究,分析了薄膜常见的表面缺陷,如节瘤,孔洞和划痕等。薄膜表面缺陷的激光损伤实验表明,不同缺陷的抗激光损伤能力不大相同。节瘤缺陷最低,约为15J/cm^2,薄膜的损伤阈值主要由其决定,孔洞的激光损伤能力与节瘤相比较高,约为节瘤的2－3倍。节瘤缺陷在低能量密度的激光损伤所形成的孔洞,与镀制过程中形成的孔洞形貌相似,激光再损伤能力也相似。低能量密度的激光把瘤缺陷变为孔洞缺陷是激光预处理提高薄膜损伤阈值的原因之一。     

BIFURCATION IN A TWO-DIMENSIONAL NEURAL NETWORK MODEL WITH DELAY

IntroductionForunderstandingthedynamicsofneuralnetworks ,thepropertiesofstabilityandbifurcationinasimplifiednon_self_connectionneuralnetwork u1(t) =-μ1u1(t) aF(u2 (t-τ2 ) ) , u2 (t) =-μ2 u2 (t) bG(u1(t-τ1) ) ( 1 )hasbeenstudied .Forexample ,inRef.[1 ]ChenandWustudiedtheexistenceoftheslowlyoscillatingperiodicsolutionbyusingthemethodofdiscreteLiapunovfunction .InRef.[2 ]thesumoftimedelaysτ=τ1 τ2 beingregardedasabifurcationparameter,theexistenceoflocalHopfbifurcationandthepropertiesof…     

哈氏合金X和C-276的力学性能及其在氢燃料电池双极板的应用研究

双极板是氢燃料电池的核心部件,由于其工作环境具有腐蚀性,要求双极板材料既具有良好力学性能,又具有良好耐腐蚀性能。本研究主要对两种典型哈氏合金Hastelloy X和Hastelloy C-276的力学性能及其作为氢燃料双极板材料的耐腐蚀性能进行测试,作为参照,也对典型不锈钢材料304 SS进行相同测试。力学性能测试结果表明,Hastelloy X,Hastelloy C-276和304 SS这3种合金材料均展现良好的延展性、较高的强度和硬度,其中Hastelloy C-276的均匀伸长率可达51.6%、硬度可达361.2 HV,Hastelloy X的屈服强度高达444.8 MPa;耐腐蚀性能测试结果表明,Hastelloy C-276在模拟的氢燃料电池腐蚀溶液(0.5 mol/L H₂SO₄+2 mg/L HF,80℃)中呈现出良好的耐腐蚀性。综合来看,Hastelloy C-276的服役性能明显高于Hastelloy X和304 SS,是最有潜力的氢燃料电池金属双极板材料。