镁钴铝类水滑石催化合成安息香甲醚

采用共沉淀法制备了镁钴铝类水滑石化合物(MgCoAl-HTLcs),并用 X 射线衍射、扫描电子显微镜、NH_3程序升温脱附等方法对 MgCoAl-HTLcs 进行了表征,并以 MgCoAl-HTLcs 为催化剂催化苯甲醛与甲醇反应合成安息香甲醚,研究了n(Mg):n(Co):n(Al)、催化剂用量、原料配比、反应温度、反应时间对合成反应的影响。表征结果显示,MgCoAl-HTLcs 的晶相完整,表面主要为弱酸、弱碱性。催化合成安息香甲醚的适宜条件为:MgCoAl-HTLcs 催化剂用量0.10 g(约为原料总质量的0.23%),n(Mg):n(Co):n(Al)=0.4:1.6:1.0,V(苯甲醛):V(甲醇)=3:50,反应温度50℃,反应时间150 min。在此条件下,苯甲醛的平衡转化率达77.49%,安息香甲醚选择性接近100%。为洁净合成安息香甲醚开辟了一条新的途径。     

How Meta-Analysis Increases Statistical Power.

One of the most frequently cited reasons for conducting a meta-analysis is the increase in statistical power that it affords a reviewer. This article demonstrates that fixed-effects meta-analysis increases statistical power by reducing the standard error of the weighted average effect size (T?.) and, in so doing, shrinks the confidence interval around T?.. Small confidence intervals make it more likely for reviewers to detect nonzero population effects, thereby increasing statistical power. Smaller confidence intervals also represent increased precision of the estimated population effect size. Computational examples are provided for 3 effect-size indices: d (standardized mean difference), Pearson's r, and odds ratios. Random-effects meta-analyses also may show increased statistical power and a smaller standard error of the weighted average effect size. However, the authors demonstrate that increasing the number of studies in a random-effects meta-analysis does not always increase statistical power. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Genetic Dissociation of Learning and Recall in Caenorhabditis elegans.

A learning event can be dissociated into 3 components: acquisition, storage, and recall. When the laboratory wild-type strain of Caenorhabditis elegans (N2 strain) is exposed to benzaldehyde in the absence of food, the worms display a reduction of their attractive response to this volatile odorant. This results from the association between benzaldehyde and a nutrient-deficient environment. Another wild-type isolate, the CB4856 strain, fails to display this decreased response to benzaldehyde after exposure to benzaldehyde in the absence of food. However, like the N2 strain, when tested to isoamyl alcohol after benzaldehyde conditioning, the CB4856 strain displays a decreased isoamyl alcohol response. Therefore, the CB4856 strain does not have an acquisition deficit, but it suffers from a recall deficit specific to benzaldehyde. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Determining pheromone content of hairpencils from individual virgin males ofPseudaletia unipuncta (Haw.) (Lepidoptera: Noctuidae)

Levels of benzaldehyde recovered from virginPseudaletia unipuncta (Haw.) males were not influenced by (1) the time hairpencils remained in the solvent (1-72 hr), (2) anesthetization or agitation of males prior to excision of hairpencils, or (3) the time (photophase or scotophase) that hairpencils were excised. Thus the interindividual variability observed is not a methodological artifact. Most males had similar concentrations in both hairpencils, although in some cases only one hairpencil contained pheromone. In one case, a male with partially extruded hairpencils had no benzaldehyde at all. Neither pupal weight nor hairpencil length proved to be reliable indicators of pheromone content.Contribution No. 373, Département de biologie, Université Laval.     

PCC载体氧化剂的制备及应用研究

制备得到各种有代表性的氯铬酸吡啶(PCC)无机载体氧化试剂,以苯甲醇选择性氧化成苯甲醛为探针反应,考察了载体、反应条件对氧化反应效率的影响,控制各载体氧化剂中PCC的负载量均为1.8 mmol/g。室温下反应,搅拌时间为30 m in,苯甲醇的氧化反应产率为:分子筛65.8%,活性炭75.4%,氧化铝94.6%,硅胶96.9%,相同条件下PCC的产率为65.8%。硅胶是制备负载PCC的优良载体,在载体氧化剂对苯甲醇的氧化反应中,一定范围内增加反应时间和载体加入量都可以提高氧化产率。     

La-OMS-2催化剂催化甲苯氧化制苯甲醛

合成了氧化锰八面体(OMS-2)分子筛,采用离子交换法和浸渍法制备了稀土金属La改性的OMS-2分子筛(La-OMS-2)催化剂,并用于甲苯液相选择性氧化制苯甲醛,考察了催化剂用量、反应温度、反应时间、氧气流量及溶剂种类对甲苯转化率和苯甲醛选择性的影响,对La-OMS-2催化剂进行了X射线衍射表征和BET比表面积测定。实验结果表明,离子交换法制备的La-OMS-2-A催化剂的活性高于浸渍法制备的La-OMS-2-B催化剂,在甲苯0.1mol、溶剂冰乙酸10mL、氧气流量60mL/min、La-OMS-2-A催化剂用量0.10g、反应温度353K、反应时间1.0h的条件下,甲苯转化率达61%,苯甲醛收率为56%。加入La对OMS-2分子筛中的MnO晶格结构产生了影响,提高了苯甲醛的收率。     

面向动态任务合作求解的联盟模型

多Agent系统中,Agent间通过形成联盟达到提高任务求解能力,获取更多收益的目的。主要关注联盟模型的改进和联盟形成阶段的改进,基于ARG(agent,role,group)元模型和学习机制提出了一种采用角色和学习机制的新联盟模型CLAR(coalition model based on learnin gagent and role);在采用合同网协议的CLAR联盟模型中提出了两阶段联盟形成机制;通过捕食者问题实验验证了角色和学习机制的作用,以及两阶段联盟形成机制在减少通讯代价上的作用。     

Interpreting the negative mood-helping literature via "mega"-analysis: A contrary view.

"Mega"-analysis was developed by M. Carlson and N. Miller (see record 1987-31249-001) as an extension of traditional meta-analytic procedures for conducting integrative reviews of existing research literatures. One such mega-analysis was conducted by Carlson and Miller to synthesize the literature on the relation between negative mood states and helping. That analysis found no support for a theoretical account (negative state relief) that had been confirmed previously by using various experimental approaches. In an attempt to reconcile the discrepancy, the logic and methods used in Carlson and Miller's mega-analysis of the negative mood-helping literature were examined, and several serious problems were found. These problems are discussed, and data are presented to show that the results of that mega-analysis, and perhaps all mega-analyses, should not be viewed with confidence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mn/Ti-Zr复合氧化物催化苯甲酸甲酯选择性加氢

以硝酸锆和钛酸四丁酯为原料,采用共沉淀法制备Ti-Zr-O氧化物载体,采用浸渍法制备了Mn/Ti-Zr催化剂;采用XRD、N2物理吸附、H2-TPR、NH3-TPD和TG-DTA对Mn/Ti-Zr催化剂进行了表征,并考察了催化剂组成、结构和反应条件对苯甲酸甲酯（MB）加氢性能的影响,以及催化剂的长周期稳定性、失活和再生行为。结果表明：TiO2含量和Mn负载量分别为12% 和8% （二者均以Ti-Zr-O氧化物的质量为基准,下同）时制备的Mn/Ti-Zr催化剂性能最优,该催化剂在θ = 390 ℃, p = 1.0 MPa,n(H2)∶n(MB) = 9∶1和重时空速（WHSV）= 0.5 h-1的优化条件能够实现98.0% 的苯甲酸甲酯转化率和89.7%的苯甲醛和苯甲醇选择性;苯甲酸甲酯加氢反应的活性和选择性分别与Mn/Ti-Zr表面MnOx物种的氧化还原性和催化剂的酸性密切相关。此外,Mn/Ti-Zr催化剂具有良好的结构稳定性,在反应1000 h后仅因积碳而丧失11% 的活性,且轻微失活的催化剂可以通过焙烧恢复其初始活性和选择性。     

准贝氏体铸钢正火热处理工艺的研究

研究了准贝氏体铸钢不同奥氏体温度正火对其组织与力学性能的影响 ,结果表明 ,随奥氏体化温度的提高 ,准贝氏体铸钢的强韧性改善 ,在 10 4 0℃正火 ,准贝氏体铸钢具有最佳强韧性配合。分析了高温奥氏体化正火强韧性提高的原因。