一种可靠多播认证方案及其C语言实现

传统的认证技术对于多播认证并不适用,因为多播认证有它自身的特殊要求。论文介绍了两种针对多播认证特点的解决方案,并结合两种方案的特点阐述了一种改进的适合可靠多播的认证方案,最后给出了C语言的实现。     

Real-time homogenous translucent material editing

This paper presents a novel method for real-time homogenous translucent material editing under fixed illumination. We consider the complete analytic BSSRDF model proposed by Jensen et al. [ [JMLH01] ], including both multiple scattering and single scattering. Our method allows the user to adjust the analytic parameters of BSSRDF and provides high-quality, real-time rendering feedback. Inspired by recently developed Precomputed Radiance Transfer (PRT) techniques, we approximate both the multiple scattering diffuse reflectance function and the single scattering exponential attenuation function in the analytic model using basis functions, so that re-computing the outgoing radiance at each vertex as parameters change reduces to simple dot products. In addition, using a non-uniform piecewise polynomial basis, we are able to achieve smaller approximation error than using bases adopted in previous PRT-based works, such as spherical harmonics and wavelets. Using hardware acceleration, we demonstrate that our system generates images comparable to [ [JMLH01] ]at real-time frame-rates.     

3G室内分布系统设计与优化关键问题

首先对3G室内分布系统特点进行介绍,然后对其设计过程中的关键问题进行分析,并给出在后续网络优化过程中的常见问题和相应解决方案。     

低频UWB SAR的冲击响应函数

提取系统的冲击响应函数(impulse response function,IRF)是测量雷达系统性能指标的前提,IRF来自理想点目标的雷达图像。对于低频超宽带合成孔径雷达(ultra wide band synthetic aperture radar,UWB SAR),参考点目标的电磁散射特性是频率和方位角的函数,不满足理想点目标的散射特性要求。本文从IRF的定义出发,结合低频UWBSAR系统处理模型,利用二维数字聚焦方法消除杂波的影响,同时利用低频电磁散射数值建模的方法计算参考点目标的电磁散射特性,最后给出了计算系统IRF的方法。     

一种精准数控STC设计方法

介绍了雷达接收机中STC控制的产生背景、原理及方法,采用MATLAB语言进行仿真,重点介绍了一种基于电控衰减器作为受控部件的数字STC控制曲线的精确设计方法,并提出了雷达STC的设计和使用原则。     

Geographic epidemiology of gonorrhea in Baltimore, Maryland, using a geographic information system

Ws/Ws rats are deficient in both mucosal- and connective tissue-type mast cells. To study the role of mast cells in active anaphylaxis, changes in vascular permeability in the trachea upon intravenous antigen challenge with Evans blue dye were examined in Ws/Ws, heterogenic Ws/+, and normal +/ + rats sensitized with the nematode Nippostrongylus brasiliensis. Antigen challenge resulted in fatal anaphylactic shock in some +/+ and Ws/+ rats, but not in Ws/Ws rats. Marked dye leakage developed within 30 min in the trachea of +/+ and Ws/+ rats, while Ws/Ws rats showed no substantial increases in the levels of vascular permeability. Ex vivo stimulation of sensitized lung fragments from +/+ animals with specific antigen induced significant releases of histamine and leukotriene (LT) C4, while sensitized Ws/Ws rat-lung fragments did not. In Ws/Ws rats, levels of nematode-specific IgE, IgG1 and IgG2a antibodies as well as levels of lung eosinophilia were not significantly different from those in +/+ rats. These results show that mast cell-deficient Ws/Ws rats fail to develop active anaphylaxis, and this is mediated probably by the lack of mast cell-derived mediators required for initiation of the reaction.     

硫磷化丙烯酸酯的合成及应用

以硫磷化合物和丙烯酸酯为原料，合成了硫磷化丙烯酸酯极压抗磨剂，该剂具有良好的热氧化安定性，水解安定性及抗乳化性能。用该剂复配抗氧剂，金属钝化剂，防锈剂及其它抗磨剂所调制的复合剂应用于32^#HM抗磨液压油中模拟数据全部达到标准要求指标。     

Tay-Sachs disease in persons of French-Canadian heritage in northern New England

This study sought to determine whether persons of French-Canadian heritage in northern New England are at high risk for the lethal infantile form of Tay-Sachs disease. In order to accomplish this, death records and laboratory diagnostic records were surveyed to ascertain Tay-Sachs deaths in a cohort of 372,000 live births between 1977-1986. The proportion of the total population with French-Canadian or Jewish heritage was determined from census and birth records, and the ethnic background of Tay-Sachs cases was determined from the corresponding birth records. In 1,860 births, both parents were of Ashkenazi Jewish heritage. One of those children was diagnosed with Tay-Sachs disease. In 41,000 births, both parents were of French-Canadian heritage, and in an additional 93,000 births, one parent was of French-Canadian heritage. No cases of Tay-Sachs disease were identified in the offspring of those individuals. Approximately 14 cases (95% confidence interval 8-20) would be expected, if the gene frequency approximated that reported for individuals of Ashkenazi Jewish heritage. Based on the results of this study, routine testing for Tay-Sachs disease heterozygosity is not indicated for persons of French-Canadian heritage in northern New England. This conclusion may not necessarily be valid for persons of French-Canadian heritage residing in other states. Further studies of Tay-Sachs disease mutations and prevalence among persons of French-Canadian heritage will be important to determine possible regional variations in gene frequencies.     

OPS和OPC系列稠油乳化降黏剂的研制

以工业品烷基酚聚氧乙烯醚OP-n（n=4,6,8,10,15）为起始原料,合成了烷基酚聚氧乙烯醚乙酸盐OPC-n和磺酸盐OPS-n两个系列的阴-非离子表面活性剂。以酸值和黏度不同的胜利单家寺和陈庄稠油为实验油样。将OPC-n和OPS-n溶于矿化度5811 mg/kg的胜利标准盐水和NaCl、CaCl2盐水中作为水相,按油、水质量比7∶3在50℃用玻棒搅拌混合,观察是否形成水包油乳状液并测黏度进行确认。在胜利标准盐水溶液中,OPC-n和OPS-n乳化稠油所需的最低质量分数,随稠油、表面活性剂类型及氧乙烯链节数n而变,一般而言,OPC-n系列中的OPC-8和OPS-n系列中的OPS-4乳化稠油的性能最好,该最低质量分数值分别为0.05%或0.025%和0.025%。在NaCl盐水溶液中,OPC-n的该最低质量分数值与稠油和n有关,均随盐含量增加而增大,在盐含量≤15%时,抗盐性最好的OPC-8和OPC-10的该值≤0.05%;OPS-n的抗盐性好于OPC-n。OPC-n的抗钙性良好,钙盐含量为2%时该最低质量分数≤0.1%;OPS-n的抗钙性更好,钙盐含量为2%和3%时该最低质量分数仅为0.025%或0.05%。表6参5。     

Clinical effects of longitudinal division of the corpus callosum in normal dogs

Longitudinal division of the corpus callosum was performed in six normal beagles to determine surgical morbidity. The corpus callosum was divided sagittally on the midline and the effect on neurological function was determined. Five of six dogs were clinically normal within 14 days or less after surgery. One dog had persistent but improving clinical signs consistent with a forebrain disturbance at 30 days after surgery. Overall, minimal morbidity and no mortality was associated with this surgical procedure. Further study is indicated to determine the efficacy of this surgical treatment for seizure control in dogs with idiopathic epilepsy.