松花江干流名称的历史演变和源头的变革

随着历史的进步和流域内少数民族部落国的兴衰，松花江干流的名称随之发生演变．在历史的长河中，嫩江和第二松花江都曾经做过松花江的干流，其源头都曾经当过松花江的源头．本文从历史的角度论述了松花江干流名称的演变和对源头认定的变革，并得出结论：仅从河流名称的历史演变是不能确定松花江源头的，松花江源头只能根据现代河流理论确定．     

非晶态Fe_(90-x)V_xZr_(10)合金吸氢现象及磁性变化的研究

利用Mossbauer谱、磁测量技术,X射线衍射以及二次离子质谱分析(SIMS)技术,对三元非晶合金Fe_(90-x)V_xZr_(10)吸氢现象及磁性变化进行了研究.实验结果表明:随充氢时间(相同的充氢电流密度)的增加,非晶态合金同质异能移位增加,表明充氢后Fe核处电子密度发生变化.随充氢量增加,室温下合金由顺磁状态转变为铁磁状态,超精细分布逐渐展宽,其最大值也向高场方向移动.吸氢后合金原子磁矩及Curie温度T_C有大幅度增加.0K时饱和磁化强度从未充氢合金的120emu/g增加到174emu/g.Curie温度T_C从257K增加到384K.吸氢导致磁性变化的机理,利用杂化理论模型能够给出很好的解释.     

Parallel in-core and out-of-core solution of electrically large problems using the RWG basis functions

Currently, the problem size that can be solved in reasonable time using the Method of Moments is limited by the amount of memory installed in the computer. This paper offers a new development that not only breaks this memory constraint, but also maintains the efficiency of running the problem in-core. In this paper, highly efficient parallel matrix-filling schemes are presented for parallel in-core and parallel out-of-core integral-equation solvers with subdomain RWG basis functions. The parallel methodology for matrix filling is quite different when using a subdomain basis as opposed to using a higher-order basis. The parallel in-core solver uses memory, which is often expensive and limited in size. The parallel out-of-core solver is introduced to extend the capability of MoM to solve larger problems that can be as large as the amount of storage on the hard disk. Numerical results on several typical computer platforms show that the parallel matrix-filling schemes and matrix-equation solvers introduced here are highly efficient and achieve theoretical predictions. The implementation of these advancements with the widely used RWG basis functions creates a powerful tool for efficient computational electromagnetics solution of complex real-world problems.     

Performance Evaluation of Single-Wavelength Fiber Delay Line Buffer With Finite Waiting Places

The performance of single-wavelength fiber delay line buffer with finite waiting places is evaluated in this paper. For Poisson arriving packets with arbitrarily distributed lengths, the generating function of delay time distribution can be derived from the quantized delay buffer model. Then queue length distributions, loss probability, and other important performance measures can be figured out. Specifically, two important cases of negative-exponentially distributed packet lengths and fixed packet lengths are considered and compared. The accuracy of the proposed approach is verified through simulation. It is also observed that the buffer system performs more effectively for the fixed-length packets.     

卫星传感器网络的定位算法及在应急通信中应用

针对应急通信系统的需求,提出了一种基于卫星传感器网络的应急监测与通信系统.介绍了卫星传感器网络的基本概念和网络结构,基于RSSI信息的多重覆盖策略,提出了一种适于卫星传感器网络的非测距定位算法-MOLA.仿真结果表明,该定位算法能够满足应急通信与监测系统对定位性能的需要.     

一种基于模版的抗仿射变换数字水印算法

文中提出了一种基于模版匹配的抗仿射变换的数字水印算法。首先对要嵌入的消息进行RS纠错编码,以增加水印提取时的抗噪能力,并在傅里叶普中频的环上且靠近十字架附近的矩形区域中嵌入水印。然后使用一个单向HASH函数来确定图像DFT变换后水印嵌入具体位置。用两条线段作为模版嵌入图像DFT变换后再做极坐标变换的域中,水印的检测及提取则采用相关系数检测。实验结果表明该算法对JPEG压缩和各种几何变换都具有较好的鲁棒性。     

MOCVD生长AlGaN/GaN/Si(111)异质结材料

利用MOCVD在Si(111)衬底上生长了无裂纹的GaN外延薄膜和AlGaN/GaN异质结构。通过优化Si衬底的浸润处理时间、AlN层厚度等参数获得了无裂纹的GaN外延薄膜,研究了SiN缓冲层和插入层厚度对AlGaN/GaN异质结电学性质的影响,2DEG的迁移率和面密度分别达到1410cm2/V.s和1.16×1013cm-2。     

基于VC-DRSA的信息系统多属性群决策安全评估

以某高校校园网络系统作为评估样本,在建立了信息系统安全属性模型的基础上,提出了基于变一致性优势关系粗糙集（VC—DRSA）的多属性群决策的安全评估方法。该方法将VC-DRSA与层次分析法（AHP）相结合,利用VC-DRSA分类质量的概念挖掘出隐含在数据背后的内在规律,在确定安全属性权重的基础上,对信息系统进行了综合安全评估。实例计算证明,该方法可以有效地解决多属性群决策的“瓶颈”问题,在信息系统安全评估中具有实际意义。     

Ultradense GaN nanopillar and nanopore arrays by self-assembly nanopatterning

We report on the details of controlled fabrication of highly crystalline gallium nitride (GaN) two-dimensional highly periodic ultradense nanopore and nanopillar arrays by self-assembly nanopatterning. Nanopore synthesis relies on the use of anodized alumina oxide template as a mask for dry etching of GaN top surface using chlorine gas. The inverse patterning is accomplished by site-selective deposition of metal nanodot array by e-beam evaporation of Ni through the pores of the template; after which the template is removed and dry etching is performed. The formed patterns demonstrate an excellent hexagonal order and uniformity according to fast Fourier transformation performed. The presented approach is robust, highly reproducible, and technically undemanding. Moreover, unreduced crystallinity of the produced nanopillars and nanopores was confirmed with Raman measurements, which suggests their possible use as future substrates for engineering advanced nano-optoelectronic devices and sensors.     

基于麻雀搜索算法的摄像机标定优化方法

针对传统摄像机标定方法标定精度低且标定可重复性差等问题,提出了一种基于麻雀搜索算法(SSA)的摄像机标定方法.首先,利用MATLAB软件中的标定工具箱,获得摄像机内参和外参的初估值,并以求出的初估值为基础,确定SSA的运行区间.然后,通过建立平均重投影误差方程,利用SSA对确定区间内的摄像机参数进行优化,获得了较小的平...