Alteration of the Route to Menaquinone towards Isochorismate-Derived Metabolites

Chorismate and isochorismate constitute branch-point intermediates in the biosynthesis of many aromatic metabolites in microorganisms and plants. To obtain unnatural compounds, we modified the route to menaquinone in Escherichia coli. We propose a model for the binding of isochorismate to the active site of MenD ((1R,2S, 5S,6S)-2-succinyl-5-enolpyruvyl-6-hydroxycyclohex-3-ene-1-carboxylate (SEPHCHC) synthase) that explains the outcome of the native reaction with α-ketoglutarate. We have rationally designed variants of MenD for the conversion of several isochorismate analogues. The double-variant Asn117Arg–Leu478Thr preferentially converts (5S,6S)-5,6-dihydroxycyclohexa-1,3-diene-1-carboxylate (2,3-trans-CHD), the hydrolysis product of isochorismate, with a >70-fold higher ratio than that for the wild type. The single-variant Arg107Ile uses (5S,6S)-6-amino-5-hydroxycyclohexa-1,3-diene-1-carboxylate (2,3-trans-CHA) as substrate with >6-fold conversion compared to wild-type MenD. The novel compounds have been made accessible in vivo (up to 5.3 g L⁻¹). Unexpectedly, as the identified residues such as Arg107 are highly conserved (>94 %), some of the designed variations can be found in wild-type SEPHCHC synthases from other bacteria (Arg107Lys, 0.3 %). This raises the question for the possible natural occurrence of as yet unexplored branches of the shikimate pathway.     

负载型复合载体及其镍基催化剂的性能

采用溶胶-凝胶法制备了负载型ZrO_2/Al_2O_3和ZrO_2/Al_2O_3-SiO_2复合载体,研究了不同复合载体对Ni基催化剂CO_2重整甲烷反应和性能的影响,并用XRD、IR、TPR、TPD和BET等方法对复合载体及催化剂进行了表征。结果表明,ZrO_2负载在基载体后比表面积、碱性、活性组分Ni的分散度和Ni与ZrO_2的相互作用增大。NiO在复合载体表面的分散容量与ZrO_2的负载量有关,ZrO_2的负载量为37．5%时NiO的分散容量达最高值(24．0%)。与Ni/ZrO_2相比,Ni/ZrO_2/Al_2O_3-SiO_2和Ni/ZrO_2/Al_2O_3催化剂对CO_2的吸附能力增大,CO_2吸附量增加,酸强度降低,CO_2重整CH_4反应活性提高,其中以Ni/ZrO_2/Al_2O_3催化剂的活性最好。     

捞油车自动排绳控制装置

针对部分油田采用捞油的采油方式，介绍的自动排绳装置，是双通道化例闭环控制系统，特点是按照输入的给定、误差信号方向、大小变化，输出信号的方向、大小随之变化，自动跟踪，自动补偿，输出速度连续无级变速，可以手动和自动工作。     

Sicherheitstechnische Maßnahmen bei der thermischen Abluftreinigung

Safety measures in thermal waste air purification units . Safety problems may arise in thermal waste air purification units from the occasional explosive nature of the exhaust gases, which may cause a flashback into the production plant. This must be avoided by the installation of safety devices that arrest a flashback. The number of such safety devices is determined by the probability of formation of explosive waste air, according to the zone classification of the explosion-protection guide. The principal explosion arrestor devices installed between combustion chamber and production plant are liquid submersion systems, detonation barriers, and dynamic flashback-free inlets into the combustion chamber, all of which must be operated under instrumental surveillance. This report presents a state-of-the-art summary of all suitable procedures and safety devices permitting safe design of systems for thermal air cleaning problems encountered in practice.     

n-Al2O3P/Ni复合刷镀层的组织和摩擦磨损特性

研究了镍基纳米Al2O3复合电刷镀层（n-Al2O3^p/Ni）的组织特征及擦磨损特性，并与快镍刷镀（Ni)进行了比较。结果表明：n-Al2O3^p/Ni复合刷镀层表面粗糙度更小，组织更致密，镀层摩擦系数随镀液中纳米粒子含量增加稍有增大；n-Al2O3在复合刷镀层中弥散分布，与基相良好结合；复合镀的耐磨性能明显优于Ni刷镀层，镀液中n-Al2O3含量为20g/L时，复合刷镀层具有最佳耐磨性能。     

Putting it all together – Formal verification of the VAMP

In the verified architecture microprocessor (VAMP) project we have designed, functionally verified, and synthesized a processor with full DLX instruction set, delayed branch, Tomasulo scheduler, maskable nested precise interrupts, pipelined fully IEEE compatible dual precision floating point unit with variable latency, and separate instruction and data caches. The verification has been carried out in the theorem proving system PVS. The processor has been implemented on a Xilinx FPGA. A shorter version of this article with the title “Instantiating uninterpreted functional units and memory system: functional verification of the VAMP” appeared in [8]. The work reported here was done while all the authors were with Saarland University.     

电控平行排列液晶光栅的光衍射特性研究

对电控平行液晶光栅的理论进行了分析,并配以结构原理图。通过对平行排列及90°扭曲排列液晶指向矢的计算,得出液晶盒中相应的折射率、相位差与电压之间的关系图,两者经比较证明平行排列更具适用性,并在实验中观测到了平行排列液晶光栅衍射特性与电压的关系。     

基于网络的家电产品故障诊断系统研究

介绍了基于网络的家电产品故障诊断系统的硬件拓扑结构、软件平台及系统开发。系统在硬件上采用了多种网络平台搭建方式及综合连接技术，软件上采用了IDRS诊断模型和基于事例的最新诊断技术。这也是诊断研究和应用的新领域。     

油气输送管线冰堵定位检测技术的开发与应用

冬季油气输送管线的冰堵时刻威胁着高寒地区石油化工装置的安全运行，带式传感器动态应变定位检测技术的研制与开发解决了这一难题，它能迅速而准确地查找冰堵点，从而保证炼化装置的冬季正常运行。