Physical parameters extraction from current–voltage characteristic for diodes using multiple nonlinear regression analysis

In this work, the two-step iteration combined with the nonlinear multiple regression technique to extract physical parameters for diodes, using a simple physical-based current–voltage (I–V) model is demonstrated. This statistical method can be applied for sampling for a wide variety of diodes including light-emitting diodes (LEDs) and Schottky diodes. Our results show the technique is an accurate and systematic approach for extracting diode parameters. The calculated recombination currents indicate the recombination efficiency for LEDs and the quality for Schottky diodes.     

不同功率氮激光穴位照射镇痛作用研究

作者以不同功率的氮澈光对大白鼠分组进行穴位照射。照射前后测痛，照射后动物痛阈都有提高，说明不同功率的氮激光均有镇痛作用。高、低功率氮澈光穴位照射后动物产生的痛阈变化经统计学处理，差异性不显著。提示使用低功率氮激光同样可达提高痛阈的目的。     

Estimation of High-Frequency Currents From Near-Field Scan Measurements

High-frequency currents on the pins of integrated circuits (ICs) and on printed circuit board (PCB) traces are needed to predict and analyze electromagnetic interference in high-speed devices. These currents can, however, be difficult to measure when traces are buried within the PCB or chip-package, especially when several current-carrying traces are in close proximity. Techniques for estimating high-frequency currents from near-field scan data are proposed in this paper. These techniques are applied to find currents on the pins of an IC, on traces buried beneath other traces in a PCB, and on traces over a slot in the ground plane. Methods of dealing with the ill-posed nature of the current-estimation problem are discussed, as are applications to electrically large structures. A study of the sensitivity of the technique to errors in the measured fields, errors in the circuit geometry, and errors in the estimated dielectric constant of the PCB or chip package show that, for reasonable errors in these parameters, currents can be estimated to within an average of 20% (1.6 dB) or less of their correct values.     

A Linear Phase Condition for Volterra Filters

In linear finite-impulse-response filter design, it is desirable that the filter frequency response has linear phase (LP). In this brief, we investigate the LP concept for nonlinear Volterra filters. The LP condition of Volterra filters is defined in terms of its output spectrum in which the phase term introduced by the Volterra kernels is linear. It is shown that under certain symmetry conditions, the LP condition is satisfied by Volterra filters. Moreover, the LP condition for Volterra filters can be considered as an extension to the linear filter case.     

Tailored and Highly Stretchable Sensor Prepared by Crosslinking an Enhanced 3D Printed UV-Curable Sacrificial Mold

Taking advantage of unlimited geometry design, 3D printed sacrificial mold cast with highly conductive polymer composites is used to prepare a sensor with designed structures. However, the disposal of the mold in a mild condition while the refined structures can be maintained is still a challenge. Herein, a bifunctional monomer hydrolyzable hindered urea acrylate is synthesized to create a cross-linked polymer network, preventing the dissolution of printed parts in the uncured resin. 3D printed scaffolds can be hydrolyzed in hot water, which provides an attractive option for sacrificial molds. Also, a porous flexible strain sensor (PFSS) is fabricated by casting polyurethane/carbon nanotubes composites into the sacrificial molds, which demonstrates a high stretchability (≈510%) and an excellent recoverability. Meantime, the pressure sensitivity (0.111 kPa⁻¹) and a long-term electrical resistance of PFSS is characterized. The resistance response signal remains nearly unchanged after 100 compressive loading cycles at a large strain of 60%. Benefiting from the design freedom of 3D printing, a practical application of the PFSS with a complex and customized structure to monitor human motion is demonstrated. These results prove that the sacrificial molding process has great potential for user-specific stretchable wearable devices.     

虚拟专用网络技术

对ＶＰＮ的基本概念作简要介绍后,着重分析了ＶＰＮ的三种典型的应用方式,即Ｉｎｔｒａｎｅｔ ＶＰＮ,远程接入ＶＰＮ和Ｅｘｔｒａｎｅｔ ＶＰＮ,并对现有的一些ＶＰＮ技术进行了总结,提出了一个一般的ＶＰＮ体系结构模型。     

基于IPSec的网络层VPN技术

文章就ＩＰＳｅｃ提供的、与网络层ＶＰＮ技术密切相关的协议隧道封装,用户信息加密,用户认证等关键技术及与之相关的系统管理等方面的技术细节进行分析,并就利用ＩＰＳｅｃ技术实现ＶＰＮ的具体方式进行了归纳。     

ATM中话音源的统计模型分析

本文根据ＡＴＭ网的传输特点,从统计的角度分析话音源的特点,建立统计模型并对其统计特性进行分析。     

低气压激光介质氦氖共振转移速率系数的测量

为了对Ｈｅ－Ｎｅ激光器的放电机理进行动力学研究，本文报导采用脉冲余辉法测量Ｈｅ－Ｎｅ共振转移速率系数，我们的测量方法比流动余辉法简单，我们测量的情况完全类似于Ｈｅ－Ｎｅ激光器的工作条件。     

在MS—Windows环境下显示汉字的方法

在ＤＯＳ操作系统下，对速度和空间要求严格的一些测控系统，可选用常驻内存的专用小汉字库解决汉字信息显示问题，在使用越来越流行的Ｗｉｎｄｏｗｓ操作环境时，讨论西文Ｗｉｎｄｏｗｓ操作系统下显示汉字方法仍有实用价值。