An improved and provable self‐certified digital signature scheme with message recovery

This paper presents a self‐certified digital signature scheme with message recovery that is proven to be secure. So far, many schemes of this kind have been proposed to keep message secret in the transmission. But Zhang et al. has proposed the man‐in‐middle attack to Shao's self‐certified signature scheme, which is based on discrete logarithm. The attacker can make a new signature by using an old one, but the reason of such man‐in‐middle attack was not referred. We present the scheme of Yoon et al., which is also based on discrete logarithm, that cannot resist man‐in‐middle attack either, give the analysis of the attack, and propose a new scheme. The proposed scheme can resist forgery attack in the random oracle model and avoid message leakage, the man‐in‐middle attack, and meanwhile has several security characters. Compared with some self‐certified schemes, our scheme is the best because of the time cost. Copyright © 2013 John Wiley & Sons, Ltd.     

A modified rain attenuation prediction model for tropical V‐band satellite earth link

Radio wave propagation plays a very important part in the design and eventually dictates performance of space communication systems. Over time, the requirements of satellite communication have grown extensively where higher capacity communications systems are needed. Escalating demands of microwave and millimetre wave communications are causing frequency spectrum congestion. Hence, existing and future satellite system operators are planning to employ frequency bands well above 10 GHz. The challenge in operating at such high frequencies for communication purposes is that there exists stronger electromagnetic interaction between the radio signals and atmospheric hydrometeors. Such instances will degrade the performance of such high frequency satellite communication systems. The development of a revised model for a better‐improved rain fade prediction of signal propagations in tropical region is considered very important. Researchers and engineers can employ the model to accurately plan the future high frequencies satellite services. Copyright © 2014 John Wiley & Sons, Ltd.     

Failure Deformation and Stress Relaxation of Heated Egg White Gels

Stress-strain relationships were determined for heated egg white gels. Compressive strain at failure was independent of protein concentration, while stress at failure increased with protein concentration. Between the length ratios of 1.6 and 2.4 before and after compression, the heated egg white gels followed the Mooney Rivlin model. In stress relaxation, the asymptotic hypothetical equilibrium modulus increased with protein concentration.     

开关磁阻电机稳态特性的等效磁网络模型分析方法Ⅰ.数学模型

本文利用开关磁阻电机的等效磁网络模型,推导出了电机绕组满足的以绕组磁链为状态变量的微分方程,建立了电机稳态运行分析的数学模型。本文成功地将非线性磁参数法的思想从单相电流系统推广到了多相电流系统,对开关磁阻电机的理论研究具有重要的意义。     

NMR investigation of experimental chemical induced brain tumors in rats, potential of a superparamagnetic contrast agent (MD3) to improve diagnosis

The different steps of development of chemically induced brain tumors were investigated in rats by MRI using a superparamagnetic contrast agent, magnetite-dextran nanoparticles (MD3). Sprague-Dawley strain pregnant female rats were injected intravenously with ethynitrosourea solution at the end of pregnancy. Offspring whelped by the inoculated mother were followed. MRI examinations were performed at 0.5 T. MD3 nanoparticles were injected intravenously at a dose of 5 mg Fe kg^-1 body weight 30 min before rat sacrifice. After sacrifice, histological slices were stained with hematoxylin-eosin. Relaxation times were measured at 40 MHz and 37°. MD3 nanoparticles act differently according to the step of the tumor development. Before tumor appearance, at a step characterized by the presence of abnormal cell clusters, relaxation time T2 increased significantly. The T2-weighted image showed a small increase in signal intensity in the lesion. Image contrast was improved by MD3 nanoparticles injection because of the decrease in healthy tissue signal intensity. The Tl-weighted image did not provide any additional information. In presence of a minute tumor, relaxation times decreased in tumor but increased in surrounding tissue. The Tl-weighted image showed a hypersignal on the border of an hyposignal. T2-weighted image showed a hypersignal in the same area. Signal intensity was not modified after MD3 nanoparticles injection. When new vascular capillaries developed in the tumor, MD3 nanoparticles cross into the cerebral parenchyma. Transmission electron microscopy showed magnetite crystals in this specific area on cytoplasm vesicles of glial cells and in tumor-specific membrane arrangements. On T2-weighted image, the hypersignal consisted of a well defined part and a second more fuzzy part, its signal being extinguished after MD3 nanoparticles injection. Necrotic areas and edema can be discriminated. The use of such a superparamagnetic contrast agent would be helpful in early detection of tumor development and in improving distinction of tumor mass from its vascular environment in patients. © 1998 Elsevier Science B.V. All rights reserved.     

用于PSPICE仿真的IGBT宏模型

介绍了一种可用于ＰＳＰＩＣＥ的ＩＧＢＴ宏模型。采用程序设计的方法,将该模型加入到ＰＳＰＩＣＥ的模型库中,并由相关测试电路对此模型进行仿真测试。该模型的仿真值与实际器件测试值相比,无论是ＤＣ特性还是开关特性均吻合较好,表明该模型可用于工程ＣＡＤ中。     

柳林泉水同位素地球化学分析及水质模型

柳林电厂水源地是以岩溶泉水作为供水水源,根据泉水温度和水质资料,同位素地球化学分析表明：柳林泉岩溶水系统可划分为受现代降水补给的浅循环子系统和由古地热水组成的深循环子系统。初步建立岩溶水对流──弥散模型,预测水源地开采条件下的水质变化。     

延河泉水源地水资源评价

依据延河泉泉域和泉区水文地质条件,计算延河泉流量,并建立二维泉域数学模型,计算上游水源地开采后对延河泉流量的削减值,从而评价延河泉的B级允许开采量。     

基于案例、规则和模型推理的电站智能诊断系统

介绍了基于案例、规则和模型的诊断推理方法,讨论了相似度计算、规则表示和复合故障的诊断等问题,论述了基于案例、规则和模型的混合推理策略,并在电站设备故障诊断系统中得到了应用。     

振动故障模糊诊断方法的研究

在建立故障机理研究和故障诊断的数学模型的基础上,分析了振动故障模糊诊断方法存在的问题。根据征兆对故障的肯定和否定程度,提出了模糊筛选矩阵,建立了反映故障诊断本质的数学模型。