一类非线性半定规划问题改进的序列线性化算法

针对一类非线性半定规划问题，提出一个改进的序列线性化算法．该方法能用于求解较大规模的优化问题，因为它处理的是比较简单的子问题．该算法利用l1-精确罚函数和信赖域型的全局优化方法，每步迭代需要解的子问题是一个二次半定规划问题，它可以用已有的半定规划软件有效的解决．在某些假定条件下，证明了算法是全局收敛的．     

Crystal structure of <Emphasis Type="Italic">Enterobacter cloacae</Emphasis> 908R class C β-lactamase bound to iodo-acetamido-phenyl boronic acid,a transition-state analogue

The structures of the class C &lt;img src="/content/l85cu2pxqcg306ye/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-lactamase from &lt;i>Enterobacter cloacae&lt;/i> 908R alone and in complex with a boronic acid transition-state analogue were determined by X-ray crystallography at 2.1 and 2.3 Å, respectively. The structure of the enzyme resembles those of other class C &lt;img src="/content/l85cu2pxqcg306ye/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-lactamases. The structure of the complex with the transition-state analogue, iodo-acetamido-phenyl boronic acid, shows that the inhibitor is covalently bound to the active-site serine (Ser64). Binding of the inhibitor within the active site is compared with previously determined structures of complexes with other class C enzymes. The structure of the boronic acid adduct indicates ways to improve the affinity of this class of inhibitors. This structure of 908R class C &lt;img src="/content/l85cu2pxqcg306ye/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-lactamase in complex with a transition-state analogue provides further insights into the mechanism of action of these hydrolases.Received 16 May 2003; accepted 4 June 2003     

时序规则分布挖掘方法

发现时序规则的有效时间段,即规则的分布,有助于对序列行为进行更深入的了解.论文介绍了一种时序规则分布的挖掘方法描述了相应的分割选择策略、频繁度量算法、知识表示生成方法、以及针对时间序列数据的规则分布挖掘系统的体系结构.该方法对于序列长度来说,时间消耗是线性增长的,并且支持在线的知识发现.使用人工生成数据与真实数据进行了实验,结果表明该方法可以有效地生成符合问题定义的规则分布表示,以应用于发现新奇的有用知识.     

关于一个非交换的格序群

群Ｇ有三个无穷阶生成元ａ,ｂ,ｃ,并且定义着关系ａ＋ｂ＝ｂ＋ａ,ａ＋ｃ＝ｃ＋ｂ,ｂ＋ｃ＝ｃ＋ａ,Ｇ＋包含ｍａ＋ｍ′ｂ＋ｎｃ（ｍ,ｍ′,ｎ为整数）当且仅当ｎ＞０或ｎ＝０而ｍ≥０,ｍ′≥０。将其中的等式改写成ａ＋（±ｂ）＝（±ｂ）＋ａ,ａ＋（±ｃ）＝（±ｃ）＋ｂ,ｂ＋（±ｃ）＝（±ｃ）＋ａ,并且给出生成元是独立的。在此基础上给出详细的证明,然后给出有关它的一些性质。     

相转移催化1,2,3-苯并三唑N-烷基化的研究

本文报道了在相转移催化(PTC)条件下1,2,3-苯并三唑的N-烷基化反应.合成了七个1,2,3-苯并三唑衍生物,实验结果表明:在以PEG800为相转移催化剂,K_2CO_3为硷的固-液PTC条件下,用各种不同的卤代烃为烷基化剂都得到满意的结果.1,2,3-苯并三唑的N-烷基化生成1-位和2-位取代的两种产物.我们比较了固-液和液-液两种PTC方法对生成1-位或2-位取代产物的影响;分离并测定了这些取代产物的红外光谱(IR),~1H核磁共振谱(~1HNMR)和质谱(MM);并对实验的结果进行了讨论.     

Substance P-induced fibrinolysis in the forearm of healthy humans

Physiological saline with or without substance P (50 ng/ml) was infused into the humeral artery in 6 healthy males. Indices of fibrinolytic activity (whole blood diluted lysis time, euglobulin lysis time, lysis areas in non-heated fibrin plates produced by plasma or euglobulin precipitate, plasminogen plasma levels, &lt;img src="/content/r5u618l266775334/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">&lt;sub>2&lt;/sub>-macroglobulin, Cl-inhibitor, and &lt;img src="/content/r5u618l266775334/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">&lt;sub>2&lt;/sub>-antiplasmin) were evaluated in the homolateral antecubital vein before and after 5 min of substance P or saline infusion. After substance P the fibrinolytic activity increased, as can be seen from the shortening of lysis times (p&lt;0.01) and enlargement of the lysis areas (p&lt;0.01). A reduction of plasminogen plasma levels (p&lt;0.01), associated with a decrease in &lt;img src="/content/r5u618l266775334/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">&lt;sub>2&lt;/sub>-anitplasmin (p&lt;0.01), was also found. Alpha&lt;sub>2&lt;/sub>-macroglobulin and Cl-inhibitor were instead unaltered by the peptide. The saline infusion, on the other hand, was unable to modify any of the examined indices. We concluded that exogenous substance P given intra-arterially increases fibrinolytic activity in locally-sampled venous blood through a mechanism which remains to be elucidated.     

Double-Talk Detection Algorithm Based on the l_2 Norm

0　IntroductionInmultimediacommunicationsystems,thecomplexcouplingbetweenaloudspeakerandamicrophonecanproduceechowhichwillseriouslycutdownthecommunicationquality .Soitiscrucialtocanceltheechowithsomeeffectivemethods.Acousticechocancellers(AEC)areusuallyusedtoeliminatelongdelayechointerferences.Typicalapplicationsareinlongdistancetelephonecircuitsorinterminalswherelongprocessingdelayexists.Fig .1showsthebasicstructureofanadaptivevoiceechocanceller.Fig .1　Thebasicstructureofanadaptivevoiceec…     

混凝土外墙与无网外保温板整体浇注施工技术

针对高层剪力墙住宅保温节能技术，介绍了现浇混土外墙与无网聚苯乙烯外保温板一次浇筑成型的保温体系，围绕这一体系，提出了施工过程中的施工工艺流程及质量控制措施。     

石蒜科6属6种植物叶表皮的初步比较研究

对石蒜科(Amaryllidaceae)中石蒜属(Lycoris Herb)，朱顶红属(Hippeastrum Herb)，文殊兰属(Crinum，L)，龙舌兰属(Agare L)，网球花属(Haemanthus L)，和君子兰属(Clivia Lindl)6属共6种植物的叶表皮结构在光学显微镜下进行了观察与比较研究。结果表明：石蒜科表皮细胞形状多数为长矩形，椭圆形或近圆形，无副卫细胞，但表皮细胞形状，大小以及气孔器分布密度在种属间存在一定的差异，可以作为鉴定该植物种及属的性状之一，同时也为石蒜科植物的系统演化提供了实验依据。     

基于有限元方法的CF/PTFE复合材料界面应力

经表面改性和未经改性的碳纤维（CF）增强聚四氟乙烯（PTFE）复合材料的弹性强度均随着碳纤维含量的增加而增强．以碳纤维增强聚四氟乙烯（CF／PTFE）复合材料弯曲强度试验结果作为依据，开展CF／PTFE复合材料界面应力的研究工作．采用各向异性等参单元，推导出在平面载荷作用下多层纤维增强复合板的层间应力分布．进一步利用有限元方法对CF／PT—FE复合材料的界面进行应力分析，并得到与试验结果相一致的结论．