CdSe四脚状纳米晶粒的光荧光研究

采用高温微乳液的化学方法,在溶液中合成了高产率的CdSe四脚状纳米晶粒。高分辨透射电镜(HRTEM)分析结果表明,CdSe四脚状纳米晶粒是由1个立方的核心和4个六方的臂所组成。研究了该四脚晶粒的变激发功率光荧光(PL)谱和变温的PL谱,分析发现低温时四脚晶粒的光荧光主要来自于被表面缺陷所局域的激子的辐射复合,而随着温度升高,束缚激子被热激发,室温时光荧光主要来自于自由激子的贡献。CdSe纳米量子点的退局域化温度比四脚纳米晶粒的高,而12K时CdSe纳米量子点的局域化能量比四脚纳米晶粒的也大得多,并对这一现象作了解释。     

高钙粘性飞灰对SCR催化剂的影响分析

为预测液态排渣炉产生的高钙粘性飞灰对选择性催化还原(SCR)催化剂的影响,通过分析烟气中飞灰浓度、粒度分布及成分组成,同时于电厂烟道中进行催化剂小样测试,表明高钙飞灰中的活性CaO与SO3的化学反应产物及粘性细灰在催化剂表面的沉积是影响催化剂活性的主要原因。对此,提出采用高效吹灰器、提高烟气流速等改善催化剂表面清洁状况的措施。     

Genome-Wide Identification and Analysis of the VQ Motif-Containing Protein Family in Chinese Cabbage (Brassica rapa L. ssp. Pekinensis)

Previous studies have showed that the VQ motif–containing proteins in Arabidopsis thaliana and Oryza sativa play an important role in plant growth, development, and stress responses. However, little is known about the functions of the VQ genes in Brassica rapa (Chinese cabbage). In this study, we performed genome-wide identification, characterization, and expression analysis of the VQ genes in Chinese cabbage, especially under adverse environment. We identified 57 VQ genes and classified them into seven subgroups (I–VII), which were dispersedly distributed on chromosomes 1 to 10. The expansion of these genes mainly contributed to segmental and tandem duplication. Fifty-four VQ genes contained no introns and 50 VQ proteins were less than 300 amino acids in length. Quantitative real-time PCR showed that the VQ genes were differentially expressed in various tissues and during different abiotic stresses and plant hormone treatments. This study provides a comprehensive overview of Chinese cabbage VQ genes and will benefit the molecular breeding for resistance to stresses and disease, as well as further studies on the biological functions of the VQ proteins.     

基于标值点过程改进的遥感道路提取新算法

研究了标值点过程的道路提取算法,针对传统数据模型提取道路不够准确的缺点,改进了数据模型。提出了基于边缘检测的生灭转移核,避免了传统的生灭过程搜索的盲目性,大大加快了算法的收敛速度。针对传统转移核容易破坏线段的连接性的缺点,定义了多种新型的RJMCMC转移核,重新设计了基于邻域的生灭转移核及线段参数转移核。仿真结果表明,改进算法大大提高了收敛速度,并且提取的道路网络更准确,更连续。     

Recovery escalation with load balancing and backup resources sharing in survivable WDM optical networks

In this paper, we propose a new survivable algorithm, called Enhanced Shared-Path Protection (ESPP), to tolerate multi-link failures in WDM optical networks. In ESPP, we consider the load balancing method to reduce the blocking probability for computing the primary paths, and we also use the idea of backup resources sharing to save backup resources for computing the backup paths. In order to tolerate multi-link failures, we perform the recovery escalation mechanism to establish new routes for carrying the traffic affected by the failures. Simulation results show that, compared with the conventional algorithm, ESPP has better resource utilization ratio, lower blocking probability, and higher protection ability.     

Study on extraction efficiency of natural antioxidant in coffee by capillary electrophoresis with amperometric detection

Capillary electrophoresis with amperometric detection (CE-AD) has been used for the determination of catechin, rutin, ferulic acid, o-dihydroxybenzene, chlorogenic acid, caffeic acid, gallic acid, and protocatechuic acid in coffee. Comparison of extraction efficiency of antioxidants using different polar solvents was also conducted by this method. Effects of several important factors including the acidity and concentration of running buffer, separation voltage, and working electrode potential, were evaluated to obtain the optimum analysis conditions. The working electrode was a 300 um carbon disc electrode at an applied potential of +0.95 V (vs. saturated calomel reference electrode). Under the optimum conditions, the analytes can be well separated within 26 min in a 75 cm length fused-silica capillary (i.d. 2.5 × 10⁻⁵ m). The current response was linear over three orders of magnitude with detection limits (S/N = 3) ranging from 6.0 × 10⁻⁸ to 3.6 × 10⁻⁷ g/mL for all analytes.     

Mailbox-based scheme for mobile agent communications

In various situations, mobile agents at different hosts must cooperate with one another by sharing information and making decisions collectively. To ensure effective interagent communication, communication protocols must track target agent locations and deliver messages reliably. Researchers have proposed a wide range of schemes for agent tracking and reliable message delivery. However, each scheme has its own assumptions, design goals, and methodology. As a result, no uniform or structured methods exist for characterizing current protocols, making it difficult to evaluate their relative effectiveness and performance. The authors propose a mailbox-based scheme for designing mobile agent communication protocols. This scheme assigns each agent a mailbox to buffer messages, but decouples the agent and mailbox to let them reside at different hosts and migrate separately.     

塔楼地下室顶板作为嵌固端条件的层刚度比计算改进方法的探讨

在工程设计实践中,由于住宅塔楼地下室的层高远大于地上一层层高,较难满足剪切刚度比要求,一般将嵌固端下移至底板.这种处理方式既不符合规范旨意,又会影响对上部结构指标的分析与处理.笔者对《JGJ3-2010《高层建筑混凝土结构技术规程》》附录一剪切刚度比公式进一步分析,考虑住宅楼塔楼与周边地下车库中墙柱构件实际高度的不同,按实建模能得到比较真实的剪切刚度比,其结果能较好地满足规范将嵌固端设计在地下室顶板的期望与要求.     

智能机械设计集成环境MIEC的研制

论述了机械设计集成环境MIEC,它是以类工程自然语言ENL解释系统为核心,利用机械设计知识、系统软件及集成环境技术研制的新型CAD系统软件。所提出的数据组织形式及对典型设计步骤保留字化的方法,在系统软件级为机械CAD引入人工智能和专家系统提供了新的条件。其中示教性的ENL语言使CAD开发工作从传统的跨学科作业转变为单学科作业,进而使CAD开发与应用结为一体。     

SiCf/SiC复材表面Sc2O3-Y2O3-ZrO2基梯度可磨耗涂层设计及性能研究

SiC_f/SiC陶瓷基复合材料是未来航空发动机重要材料之一,其表面涂层是保护SiC_f/SiC陶瓷基复合材料关键技术。针对陶瓷基复材表面的Sc₂O₃-Y₂O₃-ZrO₂基可磨耗涂层与EBC涂层结合力不够高、应力匹配性差等问题,开展Sc₂O₃-Y₂O₃-ZrO₂基梯度可磨耗涂层设计、制备与考核技术研究,并且与非梯度可磨耗涂层进行性能对比。研究结果表明:梯度可磨耗涂层比非梯度可磨耗涂层结合强度提高了6.7%;在(1 250±50)℃高温冲击1 000次后,梯度可磨耗涂层剥落面积仅为非梯度可磨耗涂层剥落面积的1/6。因此,梯度可磨耗涂层具有更好的力学性能,有望在未来航空发动机中得到广泛应用。