采油微生物YM4中试发酵培养基配方优化

对一株采油铜绿假单胞菌YM4发酵生产鼠李糖脂的培养基组成及培养条件进行了优化,优化后培养基组成为:糖蜜粉4%,玉米浆0.5%(V/V);最佳培养条件为:500 m L三角瓶装液量为100 m L,接种量10%,初始p H 7.2,35℃,180 r/min摇床培养24 h。在此条件下,发酵液的表面张力可达到28.08 m N/m,界面张力达到10-2 m N/m,比优化前节约原料成本74%。     

羧基配位剂对电镀镍–磷合金的影响

以羧基类物质作配位剂,在A3钢板表面电沉积制备Ni–P合金镀层。镀液基础组成和工艺参数为:NiSO4·6H2O 240 g/L,NiCl2·6H2O 45 g/L,NaH2PO2·H2O 50 g/L,H3BO3 35 g/L,NaF30 g/L,pH 2.0,温度70°C,电流密度2.5 A/dm2,时间20 min。研究了镀液中羧基配位剂含量对Ni–P镀层沉积速率和耐蚀性的影响。结果表明,随羧基配位剂含量增大,沉积速率减小,镀层耐蚀性先改善后变差。其适宜含量为20~30 g/L。羧基配位剂含量为25 g/L时,镀层外观光亮、结合力良好,耐蚀性和耐磨性优于未加配位剂的镀层。镀层的P含量为18.11%,属于高磷非晶态Ni–P镀层。羧基配位剂具有细化镀层晶粒的作用,使镀层表面更为平整、致密。     

深水管道复合聚氨酯弹性体保温工艺与设备

叙述了深水复合聚氨酯弹性体保温管道涂层结构、保温层涂敷预制工艺和主要设备,给出了深水管道复合聚氨酯弹性体保温生产线典型的工艺流程,并对主要设备的组成及工作原理进行了介绍。     

荷负电手性壳聚糖纳复合滤膜的制备与性能研究

以聚砜超滤膜作为基膜,以壳聚糖和壳聚糖衍生物的混合物为功能层制备纳滤膜。P2-5复合纳滤（NF）膜对Na2SO4的截留率为93%,相应的通量501.3 L/（m2·h）。电荷效应对NaCl几乎没有影响,而对Na2SO4影响显著。该膜为典型的荷负电膜,适合分离高价阴离子。     

TS-271清洗剂在清洗预膜案例中的应用

石家庄某公司循环冷却水系统停车检修期间进行了系统清洗预膜维护,通过对现场垢样的分析,进行了筛选清洗剂的一系列评价实验,现场清洗预膜效果良好,保障了循环水系统的正常运行。     

Hydrogen Acceptor‐ and Base‐Free N‐Formylation of Nitriles and Amines using Methanol as C1 Source

An N‐formylation method using methanol as the C₁ source without a stoichiometric amount of activating reagent is described. Nitriles as well as amines can be directly used as substrates. The reaction is catalyzed by an N‐heterocyclic carbene coordinated ruthenium(II) dihydride complex, which mediates methanol dehydrogenation, nitrile reduction, and C N bond formation without any external base, hydrogen acceptor, or oxidant.

     

基于混沌粒子群优化算法的NOMA功率分配研究

非正交多址接入(NOMA)技术使多个用户共享一个时频资源块,显著地提高了频谱利用率,已成为5G多址技术的研究热点。针对NOMA系统能量效率最大化问题,对非正交多址接入技术中功率分配进行了研究,提出了基于混沌粒子群优化算法的NOMA功率分配方案。建立了能量效率最大化的NOMA优化模型,利用混沌粒子群优化算法对系统功率进行分配,使NOMA系统的能量效率得到优化。仿真结果表明,当发射功率为36 dBm时,系统能量效率最大,且与传统粒子群算法相比所需迭代次数更少,获得的能量效率更优。     

Fabrication of Titanium Bipolar Plates by Rubber Forming Process and Evaluation Characteristics of TiN coated Titanium Bipolar Plates

In this study, the rubber forming process is used to fabricate a micro‐channel titanium plate for a PEM fuel cell. The micro‐channel plate is fabricated using a 200 ton hydraulic press, and various parameters (punch speed, press pressure, rubber thickness, rubber hardness) are investigated in order to evaluate the formability. TiN films are deposited by reactive DC magnetron sputtering (DCMS) with an electromagnetic field system (EMFS). For the uncoated titanium and TiN‐coated titanium substrates, the hardness, surface roughness, and corrosion resistance are estimated by nano‐indentation and electrochemical methods, respectively. The improved corrosion resistance of the TiN films can be attributed to the densification of the film caused by enhancement of nitrification with increasing high reactive nitrogen radicals. The uncoated titanium and TiN‐coated titanium bipolar plates are combined with a unit cell for a performance test, and respective current densities of 0.396 and 0.888 A cm⁻² at 0.6 V are obtained.     

激光驱动器与数控电位器/电阻之间接口分析

本文主要通过图表对激光驱动器和控制它的数控电位器/电阻之间不同方式电路接口与应用进行讨论与分析.     

一种小型化多频段天线的研究

针对移动终端小型化多功能的要求,研究了一种小型多频工作的天线。该天线由两部分构成,分别馈电,实现了无线通信中天线的小型化和多频段的要求。对其进行了仿真和测试,结果表明该天线可工作于850MHz、900MHz、1800MHz、1900MHz及2．4GHz 5个频段,覆盖频段较宽,性能较好。