BAMO-THF复合推进剂能量特性计算与分析

利用最小自由能法研究了以3,3-二叠氮甲基氧丁环(BAMO)与四氢呋喃(THF)共聚醚(PBT)为粘结剂,高氯酸铵(AP)、黑索今(RDX)、铝粉(Al)、二硝酰胺铵(ADN)为固体填料,不同增塑剂条件下推进剂比冲变化规律.理论计算表明: 以2,2-二硝基丙醇缩甲醛与2,2-二硝基丙醇缩乙醛等质量比混合物(A3)、硝化甘油与二乙二醇二硝酸酯等质量比混合物(NG/DEGDN)作增塑剂时,推进剂比冲随RDX含量变化呈抛物线形,固体填料存在最佳添加比; NG/DEGDN增塑体系推进剂比冲高于A3体系.15% ADN取代AP时,由于燃烧产物平均相对分子质量降低,推进剂比冲显著提高.     

渗透蒸发技术在肼类燃料脱水中的应用研究进展

针对肼类燃料传统脱水方法效率低、安全性差等问题,分析了渗透蒸发(pervaporaion, PV)技术的原理,回顾了该技术应用于醇/水混合物脱水研究中适用的膜材料类型和性能.综述了该技术应用于肼类燃料脱水的研究进展.分析表明,该技术可克服传统肼类燃料脱水方法的不足.根据肼类燃料的特殊性质,膜材料可选用壳聚糖、陶瓷及沸石.提出可采用多级串联脱水以提高效率.肼类燃料渗透蒸发脱水的关键研究领域包括: 低浓度水溶液中回收肼类燃料; 高浓度肼类燃料脱水; 开发高性能膜材料等方面.     

东濮凹陷砂岩储集层物性参数关系研究及随钻应用方法

储集层的物性参数是评价储集层的重要基础数据,对储集层评价的准确程度有较大影响,文章统计分析结果表明砂岩储集层岩石密度与储集层主要物性参数之间有良好的相关性。以区域统计规律为基础,建立了东濮凹陷砂岩储集层体积密度与孔隙度和渗透率的关系方程。介绍了录井施工现场应用岩屑样品体积置换法、泥岩密度计法两种常规检测方法,能较准确的获取砂岩储集层的体积密度,反演计算孔隙度和渗透率数据,合理评价储集层物性参数,为准确评价储集层提供了可信度高的重要基础数据,从而弥补了录井现场物性参数获取不足的缺陷,在随钻评价油气储集层过程中有一定的实用价值。     

Self-reported neck symptoms and use of personal computers,laptops and cell phones among Finns aged 18–65

The purpose of this study was to investigate the possible relation between self-reported neck symptoms (aches, pain or numbness) and use of computers/cell phones. The study was carried out as a cross-sectional study by posting a questionnaire to 15,000 working-age persons, and 15.1% of all respondents (6121) reported that they very often experienced physical symptoms in the neck. The results showed that they also had many other symptoms very often, and 49% used a computer daily at work and 83.9% used cell phones. We compared physical/mental symptoms of persons with symptoms in the neck quite often or more, with others. We found significant differences in the physical/mental symptoms and use of cell phones and computers. The results suggest taking into account in the future that those persons' symptoms in the neck can be associated with use of cell phones or computers.

Practitioner Summary: We investigated the possible relation between neck symptoms and use of computers/cell phones. We found that persons, who very often had symptoms in the neck, had also other symptoms very often (e.g. exhaustion at work). Their use of information and communication technology (e.g. computers) can associate with their symptoms.     

氧化芋头淀粉理化性质研究

以芋头淀粉为原料、过氧化氢为氧化剂,在碱性介质中制备了低氧化度芋头淀粉。经扫描电镜分析,氧化芋头淀粉颗粒呈多角状,平均颗粒直径18.09μm。X-射线衍射确定其晶体形貌为A型结构。流变学分析其糊化温度为79.5℃、特性粘度为2.505 Pa.s,粘弹性曲线显示其粘性大于弹性。其塑性测定结果符合Croass模型,稠度指数为85.56 s。     

以系统的理念,有效防治建筑裂渗病害

分析了导致建筑渗、漏、裂质量问题的主要原因;指出建筑渗、漏、裂问题很大程度上与业界过于依赖以物理屏障将水隔绝或封堵的技术理念有很大关系;提出要以系统的理念处理好建筑的渗、漏、裂质量问题.     

物理升华法生长ZnO晶体的研究

Zinc oxide（ZnO） has a wide band gap, high stability and a high thermal operating range that makes it a suitable material as a semiconductor for fabricating light emitting diodes（LEDs） and laser diodes, photodiodes, power diodes and other semiconductor devices. Recently, a new crystal growth for producing ZnO crystal boules was developed, which was physical vapor transport（PVT）, at temperatures exceeding 1500 ？C under a certain system pressure. ZnO crystal wafers in sizes up to 50 mm in diameter were produced. The conditions of ZnO crystal growth, growth rate and the quality of ZnO crystal were analyzed. Results from crystal growth and material characterization are presented and discussed. Our research results suggest that the novel crystal growth technique is a viable production technique for producing ZnO crystals and substrates for semiconductor device applications.     

PUF‐based solutions for secure communications in Advanced Metering Infrastructure (AMI)

Advanced metering infrastructure (AMI) provides 2‐way communications between the utility and the smart meters. Developing authenticated key exchange (AKE) and broadcast authentication (BA) protocols is essential to provide secure communications in AMI. The security of all existing cryptographic protocols is based on the assumption that secret information is stored in the nonvolatile memories. In the AMI, the attackers can obtain some or all of the stored secret information from memories by a great variety of inexpensive and fast side‐channel attacks. Thus, all existing AKE and BA protocols are no longer secure. In this paper, we investigate how to develop secure AKE and BA protocols in the presence of memory attacks. As a solution, we propose to embed a physical unclonable function (PUF) in each party, which generates the secret values as required without the need to store them. By combining PUFs and 2 well‐known and secure protocols, we propose PUF‐based AKE and BA protocols. We show that our proposed protocols are memory leakage resilient. In addition, we prove their security in the standard model. Performance analysis of both protocols shows their efficiency for AMI applications. The proposed protocols can be easily implemented.     

基于数据库查找表技术的实时红外场景仿真

为实时仿真红外场景,提出将数据库查找表技术引入红外场景仿真过程,用数据库存储表征场景景物的几何数据、热物理特征数据、光学特性数据等各类信息。在渲染红外场景时,直接访问数据库,将相关数据读入内存缓冲区,并在渲染过程中对内存中的数据进行处理,从而加快处理速度,提高仿真图像刷新帧频,增强仿真实时性。仿真实验表明,简单场景仿真图像帧频达60 Hz以上,复杂场景仿真图像帧频达20 Hz以上,仿真图像具有一定的红外特征,与实际场景基本相似。     

单元式偏光分束棱镜分束角和光强分束比

为了研究单元式偏光分束棱镜分束角和光强分束比与棱镜结构的关系,采用从理论上分析o光、e光的分束角和光强分束比与光轴取向、棱镜结构角及入射角的关系,并从实验上测量分束角和光强分束比随入射角变化的方法,进行了理论分析和实验验证,取得了分束角和光强分束比随光轴取向、棱镜结构角及入射角的变化关系的数学表达式,并得到了二者随入射角变化的实验数据。结果表明,在误差所允许的范围内,实验所测的光强分束比和分束角随入射角的变化与理论计算是一致的,且分束角的变化约为入射角的1/2。