两种电动助力转向传动机构的分析和助力曲线比较

从转向轴助力式电动助力转向系统减速传动方案出发,对可行的蜗杆传动和蜗轮蜗杆-NGW差动轮系传动两种方案进行运动学和动力学分析,总结各自优缺点.并基于两种传动机构的电动助力转向系统设计直线型助力特性曲线,分析两种机构在曲线设计中所具有的特点,为具体车型如何选择减速传动机构提供了理论依据.     

2018年广东省河源市人群乙型病毒性肝炎血清流行病学调查

目的 对2018年广东省河源市人群进行乙型病毒性肝炎血清流行病学调查,了解目标人群免疫水平,为制定免疫策略和措施提供科学依据.方法 随机采集300名门诊患者或体检人员血清,检测乙型病毒性肝炎(简称乙肝)抗体水平,并对不同性别、年龄组人群的乙肝抗体阳性率进行分析.结果 300名调查者中,乙肝表面抗原(HBsAg)、乙肝表...     

来自生活的DV灵感

如何能拍摄出一部优秀的DV作品，并且能获得业内大奖，这是许多DV发烧友梦寐以求的事。多看，多学是一条有用的途径。不过，与其向大师求教，不如借鉴身边同龄人的经验。看过杨芬的创作过程，大家是不是有了更多的灵感?     

利用HPLC-MS/MS技术进行羟自由基检测的分析方法研究

Hydroxyl radical (•OH) can cause severe damage to cells and tissues. However, its analysis is very difficult for its high reactivity and very short life. This paper present a HPLC-MS/MS method for indirectly detecting •OH by determining DMPO-OH, its addut with spin trap DMPO ( 5,5-dimethyl-1-pyrroline N-oxide ), with the N-Methyl-2-Pyrrolidone (NMP) used as internal standard. The ratio of the peak area of the DMPO-OH and NMP negatively correlate with the concentration of •OH. The results show that the method is simple, rapid, precise in both the determination of •OH and evaluation of •OH scavenging activities of antioxidants.     

Preparation of highly dispersed antimony-doped tin oxide nanopowders by azeotropic drying with isoamyl acetate

Antimony-doped tin hydroxide colloid precipitates were prepared by hydrolysis of SnCl4·5H2O and SbCl3 ethanol solutions. Isoamyl acetate was selected as azeotropic drying solvent and was compared with the most commonly used n-butanol solvent on treating precipitate for low hard agglomeration precursor powders. The FT-IR, BET, XRD, and TEM results of the precursor powders and calcinated antimony-doped tin oxide powders were recorded. The results demonstrate that isoamyl acetate is an excellent azeotropic drying solvent that can effectively prevent the agglomeration of particles and greatly improve the fluffiness of the obtained dried powders. After these precursor powders are calcined, antimony-doped tin oxide nanopowders with tetragonal futile structure and high dispersivity can be obtained.     

基于物理参数水文模型的水资源评价UCMV方法

“还原失真”和“还原失效”是变化条件下水资源评价中的棘手问题之一。本文提出基于物理参数的分布式水文模型用于变化环境下水资源评价的原理和假定，以及基于此的UCMV(Up-reach for Calibration and Mid-reach for Validation) Process水资源评价方法。以永定河山区流域为实例，进行了不同时期下垫面的水资源评价。结果表明，流域1990年代和2000年代下垫面条件下多年平均地表水资源量分别为10.799亿m3和9.892亿m3，后者相对于前者产流能力降低了8.0%，清楚地表现出下垫面变化对流域产流能力的影响，也进一步证实了“还原失效”现象的存在以及基于物理分布式水文模型进行变化环境下的水资源评价的有效性。     

矿井互逆双环光纤主干通信网研究

结合下一代矿区通信网分层模型和矿井通信网的总体架构,提出矿井通信网的整体拓扑结构应该是:主干部分沿主要巷道构成光纤自愈环,在地面与矿区通信环网相切,井下其它部分则根据巷道分布特点、信息流量和可靠性等要求,构成分支树型或局部环型,就近连接到主干环的结点上.矿井主干环采用互逆双环拓扑结构,通过空间重利用技术提高带宽利用率,采用插入缓冲技术实现数据的快速转发.     

关于做好新形势下女干部培养选拔工作的思考

培养选拔女干部是建设高素质干部队伍的重要组成部分,也是实现男女平等、构建社会主义和谐社会的必然要求。社会主义市场经济体制的不断完善,既使妇女面临比以往任何一个时代更加严峻的挑战,又为其施展才华提供了更多的机遇。要制定培养选拔使用女干部的措施,必须认清形势,分析有利条件和困难,根据女性成长规律,创新工作方法,切实把优秀的妇女干部培养选拔出来。