军用电子设备电源线传导发射抑制方法设计及实现

针对某内场测试设备在CE102项(10 kHz~10 MHz电源线传导发射)测试中超差的问题,对超差原因进行了分析,然后结合电磁兼容设计原则,设计了一系列抑制传导发射的改进方法,包括电源线接线关系优化和滤波器安装接线优化等,最后通过试验进行验证。测试结果表明,改进后的设备电源线传导发射电平在低频段(10~30 kHz)和高频段(6~10 MHz)有超过10 dB的下降。所设计的方法容易实施且具有通用性,可为类似军用电子设备的设计提供参考。     

RFW102无线收发芯片组的原理和应用

RFW102芯片组是一种半双工DSSS(直接序列扩频技术 )的无线收发两用IC ,它采用ASK调制方式 ,工作频率在2.4GHz。文中详细介绍了该芯片组的特点、性能、管脚功能和工作原理 ,给出了RFW102的应用电路     

(Z)-9-tetradecen-1-OL formate

Concentrations in air of (Z)-9-tetradecen-1-ol formate (Z-9-tdf), a mating disruptant ofHeliothis moths, were measured intermittently over a 22-day period in a corn field. The chemical was emitted from laminated plastic (Hercon^®) dispensers arranged in a square grid with 10-m spacing. Measurements were made at three heights near the center of the treated plot and 1 m downwind from disruptant dispensers. Concurrent measurements were made of wind speed, air temperature, and temperature gradient.Z-9-tdf concentrations ranged from below detectable levels to 195 ng/m³ and were generally highest in the horizontal plane of the dispenser. As wind speed decreased near sunset, concentrations increased sharply, then decreased again near midnight. SinceHeliothis moths mate in the evening and early night, the concentration pattern was favorable for mating disruption. Strong temperature inversions within the crop canopy, which occurred daily before sunset, did not apparently affectZ-9-tdf concentrations. Concentrations decreased steadily on successive sampling days after application, and, by day 27, ranged from 0 to 30% of those on day 6. The data suggest that the corn plants and the soil may act as sinks for the chemical vapor at night.     

电站锅炉受热面涂层抗高温氧化性能的研究

针对电站锅炉受热面因高温氧化而导致的爆漏,采用Q235低碳钢作为基体,分别喷涂PS45、FeCrAl、4Cr13等3种涂层,与没有涂层保护的钢研102钢管材进行抗高温氧化试验。结果表明,没有涂层保护的钢研102钢抗氧化能力较差,而Q235低碳钢经电弧喷涂保护后其抗氧化性能得到大幅度的提高。其中,PS45涂层中由于Cr、Ni含量较高,在试样表面可持续形成结构致密、性质稳定的Cr2O3保护层,具有优异的抗氧化性能,使试样得到充分保护。     

USB数字电视接收棒的设计与实现

对一种基于USB2．0的国标DMB—TH数字电视接收棒的系统实现方案进行了研究,采用ADMTV102高频头,凌汛DMB—TH信道解调器,CY7C68013-USB2．0传输控制芯片和基于DirectShow技术的媒体播放器。介绍了系统各部分相应的软硬件构成以及整个系统的实现过程。经验证,该方案体积小、功耗低、支持热插拔、接收播放效果良好,有很好的市场前景。     

Stabilization of the Reductase Domain in the Catalytically Self‐Sufficient Cytochrome P450BM3 by Consensus‐Guided Mutagenesis

The multidomain, catalytically self‐sufficient cytochrome P450 BM‐3 from Bacillus megaterium (P450_BM3) constitutes a versatile enzyme for the oxyfunctionalization of organic molecules and natural products. However, the limited stability of the diflavin reductase domain limits the utility of this enzyme for synthetic applications. In this work, a consensus‐guided mutagenesis approach was applied to enhance the thermal stability of the reductase domain of P450_BM3. Upon phylogenetic analysis of a set of distantly related P450s (>38 % identity), a total of 14 amino acid substitutions were identified and evaluated in terms of their stabilizing effects relative to the wild‐type reductase domain. Recombination of the six most stabilizing mutations generated two thermostable variants featuring up to tenfold longer half‐lives at 50 °C and increased catalytic performance at elevated temperatures. Further characterization of the engineered P450_BM3 variants indicated that the introduced mutations increased the thermal stability of the FAD‐binding domain and that the optimal temperature (T_opt) of the enzyme had shifted from 25 to 40 °C. This work demonstrates the effectiveness of consensus mutagenesis for enhancing the stability of the reductase component of a multidomain P450. The stabilized P450_BM3 variants developed here could potentially provide more robust scaffolds for the engineering of oxidation biocatalysts.     

ZL102铝合金在3% NaCl溶液中的微区电化学特性

采用扫描电化学显微镜技术(SECM)深入研究了ZL102铝合金在3%NaCl(质量分数)溶液中的腐蚀行为,用光学显微镜和扫描电镜观察其腐蚀形貌,用能谱仪对夹杂物和腐蚀产物进行分析。结果表明:在3%NaCl溶液中,金属间化合物与ZL102铝合金基体形成微电池,金属间化合物的电位高于基体的,使基体优先腐蚀溶解;腐蚀过程中铝合金表面活性不稳定,是因为尺寸较小的金属间化合物因周围基体溶解容易脱落,并在其他区域沉淀,只有尺寸较大的金属间化合物周围基体产生持续腐蚀溶解,最终形成点蚀。     

The role of the conserved threonine in P450 BM3 oxygen activation: substrate-determined hydroxylation activity of the Thr268Ala mutant

The hydroxylation activity of the Thr268Ala mutant of P450(BM3) has been shown to occur to varying degrees with small alterations in the structure of a fatty-acid substrate. Ten substrates were investigated, including straight chain, branched chain and cis-cyclopropyl substituted fatty acids with a straight-chain length that varied between 12 and 16 carbon atoms. The efficacy of the hydroxylation activity appeared to be governed by the chain length of the substrate. Substrates possessing 14 to 15 carbons afforded the highest levels of activity, which were comparable with the wild-type enzyme. Outside of this window, straight-chain fatty acids showed reduced activity over the other substrate types. These results provide a cautionary tale concerning the loss of ferryl activity in such cytochrome P450 threonine to alanine mutants, as the nature of the substrate can determine the extent to which hydroxylation chemistry is abolished.     

浅谈M102-M低压电动机综合保护装置

随着自动化生产的要求,电动机智能保护器要能够实现剥生产过程和大型机械的遥控、遥测、遥调、故障诊断以及集中控制等功能。而文章主要简述了某石油化工厂区域变使用的能够实现此一系列功能的M102－M智能电动机综合保护器的硬件结构、系统功能、参数设置和常见故障及处理。     

“海洋石油102”FPSO生产系统工艺流程改造与实践

随着渤中28-2南油田群新油井的投产,“海洋石油102”FPSO货油舱原油进舱量增加,使得原来的原油入舱管线不能满足现状,从而导致了生产系统处理能力下降.对“海洋石油102”FPSO生产系统工艺流程进行了改造,利用原有设备新增入舱管线使FPSO生产系统处理的原油与上游平台输送来的合格原油分别进入货油舱.实践效果表明,“海洋石油102”FPSO生产系统工艺流程的改造,在大幅提高了FPSO生产系统处理能力的同时,也增加了上游平台的原油处理能力和输送能力,为渤中28-2南油田群进一步提高产量成功解决了瓶颈难题.