一种改进的ALOHA防碰撞算法

针对现有动态帧时隙ALOHA防碰撞算法在射频识别系统中的标签识别效率最高只能达36.8%的问题,利用标签码元序列的唯一性,改进经典的动态帧时隙ALOHA防碰撞算法中随机选择时隙的方式,提出一种基于标签码元的碰撞序列进行时隙选择的方法,有效降低了标签碰撞的概率,从而提高系统识别效率。仿真结果表明改进的ALOHA标签防碰撞算法识别效率最低为37.5%,随着实际标签数目与碰撞位序列所能确定的标签数目越接近,识别效率越高,最高能达到100%,明显优于现有的动态帧时隙ALOHA算法。     

Could SGLT2 Inhibitors Improve Exercise Intolerance in Chronic Heart Failure?

Despite the constant improvement of therapeutical options, heart failure (HF) remains associated with high mortality and morbidity. While new developments in guideline-recommended therapies can prolong survival and postpone HF hospitalizations, impaired exercise capacity remains one of the most debilitating symptoms of HF. Exercise intolerance in HF is multifactorial in origin, as the underlying cardiovascular pathology and reactive changes in skeletal muscle composition and metabolism both contribute. Recently, sodium-related glucose transporter 2 (SGLT2) inhibitors were found to improve cardiovascular outcomes significantly. Whilst much effort has been devoted to untangling the mechanisms responsible for these cardiovascular benefits of SGLT2 inhibitors, little is known about the effect of SGLT2 inhibitors on exercise performance in HF. This review provides an overview of the pathophysiological mechanisms that are responsible for exercise intolerance in HF, elaborates on the potential SGLT2-inhibitor-mediated effects on these phenomena, and provides an up-to-date overview of existing studies on the effect of SGLT2 inhibitors on clinical outcome parameters that are relevant to the assessment of exercise capacity. Finally, current gaps in the evidence and potential future perspectives on the effects of SGLT2 inhibitors on exercise intolerance in chronic HF are discussed.     

My personal history in the early explorations of computer graphics

Gary Demos discovered computer graphics while hearing a computer-generated film presentation at CalTech in 1970 by John Whitney Sr. Gary then began working under the direction of Ivan Sutherland in Utah to develop early computer graphics hardware and software. In 1974 Gary and John Whitney Jr. started the “Motion Picture Project” at Information International to produce computer generated simulated scenes for movies (Futureworld, Looker, and Tron) and commercials. These early computer-generated visuals were quite challenging given the level of software and hardware technology available in the 1970’s. In 1981 Gary and John left Information International to form Digital Productions, where they produced effects for the movies Last Starfighter and “2010”, which were both released in 1984. Digital Productions used the Cray XMP computer, together with the Digital Film Printer that they had developed at Information International. Following a hostile takeover by Omibus of Digital Productions in 1986, Whitney/Demos Productions was formed, using a Thinking Machine parallel computer. This paper describes the technical challenges and achievements of this early visual computing.     

基于随机森林回归的清防垢加药量预测方法

复合驱由于强碱化学剂的注入易造成严重的结垢现象,而预测清防垢加药量是制定科学的清防垢方案的关键.为了获得一种具有较强实用价值和较高预测精度的复合驱清防垢加药量的预测方法,该文将随机森林回归算法应用到复合驱清防垢加药量预测.首先,分析并处理影响清防垢加药量的20维特征,利用随机森林回归的特征重要性评估功能对影响加药量的众...     

A computer program for internal conversion coefficients and particle parameters

Title of program: CATAR Catalogue number: ABGP Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland (see application form in this issue) Computer: UNIVAC 1108; Installation: Sandoz A.G., Basel, Switzerland Operating system: EXEC 8 Programming language used: FORTRAN IV High speed store required: 26K words No. of bits in a word: 36 Overlay structure: None Number of magnetic tapes required: None Other peripherals used: Card reader, line printer Number of cards in combined program and test deck: 3136 Card punching code: BCD     

一种伪随机码引信对TBM目标的电磁散射特性分析

分析了 TBM目标特点 ,针对一种伪随机码引信 ,计算了该目标的镜面反射点的位置和强度 ,建立了目标近区电磁散射的数学模型 ,给出了针对该引信的目标回波信号的表达式     

一个在线考试系统的设计与实现

网上考试作为网络教学和校园信息化建设的较为重要的部分,有其独特的需求和作用。本文论述了采用生成随机数方法的一个在线考试系统的功能和数据库的设计与实现过程。     

LD端面抽运激光介质热效应的有限元分析

针对激光介质的通光面为方形、抽运光为高斯光束的情况,以Nd:YAG激光介质为例,用ANSYS有限元软件模拟了激光介质的热效应,精确地给出了激光介质中各点的温度和温度分布。分别对提高介质侧面对流换热系数、降低冷却液温度、抽运端面水冷这3种情况下的温度场进行了模拟。结果表明,通过提高晶体侧面的热对流换热系数和降低冷却液温度,几乎不能降低激光介质的热效应,而通过抽运端面水冷,可有效地降低激光介质的热效应。     

纳米限域材料的制备及其在污染治理中的应用研究进展

纳米技术在环境污染治理中具有广泛前景,然而其在应用过程中存在纳米颗粒及活性中心易团聚失活的问题。将纳米粒子的活性中心限制在载体的孔道内,构建出新型纳米限域材料可以有效克服这一缺点。同时,凭借材料的纳米限域效应,一定程度上可影响水的氢键网络结构,并会影响反应中中间活性粒子的演化、传质速率、晶体的生长和成核阶段过程,以及提高局部空间内反应底物的浓度。本文系统梳理了纳米限域材料的制备方法,并对比分析了各种制备方法的优缺点,归纳总结了近年来纳米限域材料在吸附和高级氧化降解污染物中的研究进展,展望了未来纳米限域材料在环境污染物治理领域的研发及应用前景。     

传爆序列飞片起爆理论研究及应用

在考虑受主炸药盖片对撞击入射冲击波衰减作用的基础上，得到了改进的飞片起爆计算模型，经与实验结果对比表明这一改进模型更符合实际系统。