Top-Seeded Melt-Growth of YBa2Cus3Ox Crystals for Neutron Diffraction Studies

We have grown cubic centimeter-size crystals of YBa₂Cu₃O _x suitable for neutron studies, by a top-seeded melt-growth technique. Growth conditions were optimized with an eye toward maximizing phase purity. It was found that the addition of 2% Y₂BaCuO₅ and 0.5% Pt (by mass) were required to prevent melt loss and to obtain the highest crystallinity. A neutron diffraction study on a mosaic of six such crystals found that the final Y₂BaCuO₅ concentration was 5%, while other impurity phases comprised less than 1% by volume. The oxygen content was set to x = 6.5, the crystals were detwinned, and then carefully annealed to give the well-ordered ortho-II phase. The neutron study determined that 70% of the mosaic's volume was in the majority orthorhomic domain. The neutron (006) and (110) rocking curve widths were ～1° per crystal and ～2.2° for the mosaic, and the oxygen chain correlation lengths were >100 Å in the a- and b-directions and ～50 Å in the c-direction.     

Nitrogen management in reservoir catchments through constructed wetland systems.

In this study, nitrogen removal was investigated in pilot-scale subsurface flow (SSF) and in free water surface flow (FWS) constructed wetlands installed in the campus of TUBITAK-Marmara Research Center, Gebze, near Istanbul, Turkey. The main purposes of this study are to apply constructed wetlands for the protection of water reservoirs and to reuse wastewater. Experiments were carried out at continuous flow reactors. The effects of the type of plants on the removal were investigated by using emergent (Canna, Cyperus, Typhia spp., Phragmites spp., Juncus, Poaceae, Paspalum and Iris.), submerged (Elodea, Egeria) and floating (Pistia, Salvina and Lemna) marsh plants at different conditions. During the study period HLRs were 30, 50, 70, 80 and 120 L m(2)d(-1) respectively. The average annual NH4-N, NO(3)-N, organic N and TN treatment efficiencies in SSF and FWS wetlands are 81% and 68%, 37% and 49%, 75% and 68%, 47% and 53%, respectively. Nitrification, denitrification and ammonification rate constant (k20) values in SSF and FNS systems have been found as 0.898 d(-1) and 0.541 d(-1), 0.488 d(-1) and 0.502 d(-1), 0.986 d(-1) and 0.908 respectively. Two types of the models (first-order plug flow and multiple regression) were tried to estimate the system performances.     

家用电器纳米抗菌材料

家用电器已经成为越来越多家庭中不可或缺的生活品,同时由于电器使用过程中细菌滋生导致的健康问题越来越受到人们的关注,因此,家用电器的抗菌效果成为了大众评判健康生活的指标之一.而纳米材料由于其成本低廉并拥有较好的抗菌效果,可以作为解决这一问题的途径之一.对家电行业已经初步应用的三种成本低、无需附加苛刻条件、抗菌效果好的纳米材料进行分析并研究,指出开发更加优异的纳米抗菌材料是当前抗菌行业的热点.     

基于卡口上下文和深度置信网络的车辆轨迹预测模型研究

针对车辆轨迹预测中节点序列的时序特性和实际路网中的空间关联性,该文提出一种基于深度置信网络和SoftMax (DBN-SoftMax)轨迹预测方法.首先,考虑到轨迹在节点集合中的强稀疏性和一般特征学习方法对新特征的泛化能力不足,该文利用深度置信网络(DBN)较强的无监督特征学习能力,达到提取轨迹局部空间特性的目的;然后,针对轨迹的时序特性,该文采用逻辑回归的预测思路,用当前轨迹集在路网特征空间中的线性组合来预测轨迹;最后,结合自然语言处理领域中的词嵌入的思想,基于实际轨迹中节点存在的上下文关系,运用节点的向量集表征了节点间的交通时空关系.实验结果表明该模型不仅能够有效地提取轨迹特征,并且在拓扑结构复杂的路网中也能得到较好的预测结果.     

星上一体化电子系统的FDIR框架设计与研究

传统的卫星往往要在硬件设计开发后,才能针对具体硬件平台进行星载故障检测隔离恢复(FDIR)设计,这就使得整个卫星系统开发周期增长,FDIR软件也无法重用.首先分析了星上故障检测隔离和恢复的特殊性和必要性,在概述FDIR的基本概念、相关技术方法以及卫星数据模型(SDM)平台的基础上,提出了一个基于SDM平台的星上一体化综合电子系统FDIR框架,既克服传统卫星针对"一星一平台"的FDIR设计,又能方便整星的信息融合,提高FDIR能力.     

基于MCF52223USB数据采集系统的实时性研究

详细分析了基于USB传输的数据采集系统的实时特性。针对实时工业控制环境,研究了采用32位微处理器MCF52223进行AD采集,并通过USB总线通信方式向PC机传送AD数据的多路数据采集系统的实时特性,并从软件滤波、数据传输等方面提出了提高系统实时性的有效方法,最后较为具体地给出了MCU方和PC方的编程方法。     

LU分解和Laplace算法在GPU上的实现

随着图形处理器(GPU)性能的大幅度提升以及可编程性的发展,已经有许多算法成功地移植到GPU上.LU分解和Laplace算法是科学计算的核心,但计算量往往很大,由此提出了一种在GPU上加速计算的方法.使用Nvidia公司的统一计算设备架构(CUDA)编程模型实现这两个算法,通过对CPU与GPU进行任务划分,同时利用GP...     

Production of single-chain Fv antibodies against melamine from a rabbit phage display library for the development of a melamine immunoassay

A rabbit phage display library of single chain Fv (scFv) antibodies was constructed to screen specific scFv antibodies against melamine. Rabbits were immunized with melamine immunogens prepared via glutaraldehyde method. Two recombinant scFv antibodies with high specificity for melamine, termed A9 and B4, were isolated via library panning. SDS-PAGE analysis showed that the soluble A9-scFv and B4-scFv antibodies were expressed successfully and the scFvs showed good sensitivity with an IC₅₀ of 12.64 and 10.32 μM to melamine, respectively. The cross-reactivity of 2 scFv antibodies with cyanuric acid and chloromycetin were below 1%. The high similarity of 2 scFv nucleotide sequences indicated that they may originate from 1 B cell clone that had undergone somatic diversification. As a consequence, the conjugation synthesis was successful and the selected scFvs could be used for sensitive detection of melamine in foods and feeds by immunoassay.     

一种高效的模拟覆盖率分析方法研究

在覆盖率驱动的模拟验证方法中,模拟覆盖率分析时间直接影响模拟验证的效率．针对现有基于值变化导出(VCD)文件覆盖率分析方法中模拟重放效率低的问外,对模拟重放过程进行了改进,提出一种高效的基于VCD文件的模拟覆盖率分析方法．该方法模拟重放时只针对HDL描述中的控制语句进行求解．实现了模拟覆盖率分析系统原型和各种覆盖率测度的分析方法．实验结果表明该方法在获得与现有方法同等覆盖率分析精度的同时,模拟重放效率提高2倍多．