信令网关在软交换中的应用

软交换技术是下一代网络(NGN)的核心技术,其中信令网关(SG)是软交换中的重要组成部分。文章主要研究了软交换中SG的应用。首先介绍了软交换技术以及软交换在NGN中的应用,接着从SG的介绍和SG的应用两方面,对SG技术作了全面的阐述,着重讲述了如何通过不同的信令适配层协议实现SG与软交换的互通。     

基于Multi—agent的物流管理系统规划求解

为实现物流管理系统中的资源分配问题,分析了物流管理中任务的特点,提出了在应用multi-agent的物流系统中规划的表示方法,并提出了一种分布式求解方法。这种分布式方法是在对状态空间的层次分析基础上,利用状态空间结点之间的联系,实现求解中多agent相互促进的合作。     

Comparison of reconstruction methods of depth distribution of tritium in materials based on BIXS

Three reconstruction methods based on Tikhonov regularization are used to solve the ill-posed inverse problem when incorporating Monte Carlo calculations into the β-ray induced X-ray spectrometry (BIXS) for analyzing the tritium content and depth distribution in the material surface. These methods are implemented by the GENEREG, CONTIN and REGUTOOLS codes, respectively. The tritium sample is assumed to be a molybdenum slab of 5 μm thickness, and an argon gas of 5 mm thickness is filled in front of the molybdenum slab. The Monte Carlo code PENELOPE is used to simulate the X-ray energy spectra induced by tritium’s β-decays. The reconstruction results for tritium depth distributions by these three codes are compared and the comparison shows that the code GENEREG can give satisfactory results. Some discussions are made.     

化工原理精馏过程的计算机辅助计算

精馏过程为化工原理教学过程中的重点和难点部分,公式多,计算过程复杂,采用传统的板书讲解方式难以达到较好的授课效果。本文利用MATLAB语言强大的运算与图形表达功能,通过剖析精馏计算过程中的典型例题,给出了计算机辅助计算精馏过程的具体思路和方法。论文中还充分展现了采用计算机进行图解法解题的优越性,从而增强教学过程的直观性和可视性,加深学生对精馏单元的理解。     

The effect of umbrella-type branching on the blood circulation and tumor targeting of star-branched PLA-PMPC copolymer micelles

The effect of branching on the blood circulation and tumor targeting of polymer nanovehicles in vivo was investigated in this study. For the purpose, star-branched poly(lactic acid) and poly(2-methacryloyloxyethyl phosphorylcholine)(PLA-PMPC)copolymers with umbrella-type AB_3,(AB_3)_2, and(AB_3)_3 architecture were synthesized by branching at the PLA core. Micelles self-assembled from these copolymers were used to evaluate the effect of core branching on blood circulation and tumor targeting. The results showed that branching changed the behavior of polymeric self-assembly in solution, thereby changing the size and surface anti-fouling performance of the polymeric micelles. Moreover, star-branched copolymer micelles with a higher branching degree allowed their payload to persist better in blood(half-time prolonged from 7.1, 8.6 to 13.8 h) and for a 1.72-fold higher content at the tumor site. These studies suggest that raising the branching degree of amphiphilic copolymer potentially offers a promising strategy for the design of carriers capable of enhanced circulation and targeting in vivo.     

Global bifurcations of strongly nonlinear oscillator induced by parametric and external excitation

The global bifurcation of strongly nonlinear oscillator induced by parametric and external excitation is researched. It is known that the parametric and external excitation may induce additional saddle states, and result in chaos in the phase space, which cannot be detected by applying the Melnikov method directly. A feasible solution for this problem is the combination of the averaged equations and Melnikov method. Therefore, we consider the averaged equations of the system subject to Duffing-Van der Pol s...     

Improvements on voltage-resistant performance of bipolar static induction transistor (BSIT) with buried gate structure

The breakdown mechanism of power bipolar static induction transistor (BSIT) with buried gate structure is analyzed in depth.A power BSIT sample with high voltage-resistant capability has been designed and fabricated in this paper.The technological methods for improving high voltage performances are represented.The active region of BSIT is surrounded with a deep trench to avoid any probable influences of various defects on device performances.Two field-limiting ring-shape junctions and one channel termination ring-shape junction are arranged around the gate region to reduce the electric field intensity.The gate-source breakdown voltage BV GS of power BSIT has been increased to 110 V from previous value of 50-60 V,and its blocking voltage is increased to 1700 V.The optimal geometrical dimensions for achieving the maximum breakdown voltage BV GS and blocking voltage V block are also represented in the paper.     

氚老化对海绵钯吸、放氕氘热力学性质的影响

钯是氚处理工艺中的关键功能材料,氚衰变及其产生的氦会引起钯的贮氢性能下降。对室温下贮氚老化1.6年的海绵钯进行了预处理,采用变温法获得了老化钯吸、放氕和氘的PCT曲线,作为对比,同时给出了新鲜钯的实验结果。在此基础上,进行了氚老化钯吸、放氕和氘热力学性质分析。结果显示,氚老化会导致钯氢体系的α相右移、坪台压降低、坪台区变窄,且老化效应对钯氢体系的滞后效应、焓变及熵变产生影响。     

基于PPP模式的建筑垃圾资源化产业研究

为解决建筑垃圾资源化产业项目融资不足、管理困难的难题,提出在建筑垃圾产业中引入PPP模式可实现政府和企业"双赢"的效果。经过对比分析,BOO是最适合建筑垃圾处理产业项目的模式。通过对建筑垃圾资源化产业PPP运行模式和效益分析,得出PPP模式应用于建筑垃圾资源化产业项目是切实可行的。     

基于Mirman模型的镀通孔焊盘应力评估有效性研究

Mirman焊盘挠应模型只考虑镀通孔(plated through hole,PTH)焊盘与孔壁结合处完全弹性或完全塑性的两种极限边界条件,而实际上该结合处通常是处于两种极限条件之间的某种状态.文中在Mirman模型的基础上,通过变动表征焊盘与孔壁结合处约束程度的边界条件系数(B)的方法,得到一般边界条件下的焊盘挠度模型,进而得到镀通孔焊盘应力评估模型.采用解析和有限元两种方法对镀通孔焊盘应力进行计算,结果表明B的取值对应力计算结果有很大的影响,这种影响与环境参数(如温度)无关,而与镀通孔的几何参数有关.