GPS/INS组合技术在山区丛林中的导航定位方法

本文首先简要介绍了惯性导航系统的工作原理、基本组成及其与GPS相比较的优缺点,重点讨论了GPS/INS组合技术及其在山区丛林中导航定位的方法.     

电气设备接地引下线导通测试及分析

介绍了利用接地引下线导通测试仪测试电力设备接地引下线的方法及注意事项，并对若干测试数据进行了分析，给出了判定导通状况的参考值。     

Thermal analysis,glass transition temperature and rheological behaviour of emulsion copolymers of methyl methacrylate with styrene

Poly(MMA‐ran‐St) samples were synthesized under monomer‐starved conditions (drop feeding method) by emulsion copolymerization. Their thermostability was determined by thermogravimetric analysis. The glass transition temperature (T_g) of the copolymers was determined by differential scanning calorimetry (DSC) and torsional braid analysis (TBA). The results showed that the MMA–St copolymers exhibit an asymmetric T_g versus composition curve, which could not be interpreted by Johnston's equation, taking the different contributions of the diads to the T_g of the copolymer into consideration. A new sequence distribution equation taking into account the different contributions of the triads was proposed to predict the copolymer T_g. The new equation fitted the experimental data exactly. The T_g determined by torsional braid analysis (TBA) is higher than the one determined by DSC, but the difference is not constant. The rheological behaviour of the copolymers was also studied and T_gTBA‐T_gDSC increased with the increasing flow index of the copolymer. © 2003 Society of Chemical Industry     

纯净水中病毒三种富集方法的比较

目的 比较膜吸附法、膜吸附-PEG法和膜吸附-超滤法对纯净水中病毒的富集效果,并对优选的富集方法的实验条件进行比对,旨在寻找高效的方法,为其他水体中病毒富集检测提供技术借鉴。方法 本文以MS2噬菌体为目标病毒,制作高、低浓度水样,建立逆转录-荧光定量聚合酶链式反应(RT-qPCR)方法的标准曲线,进行定量检测。使用膜吸附法、膜吸附-PEG法和膜吸附-超滤法富集水样,并比较不同过滤膜、不同超滤管及两种核酸提取方法的回收率,选择最适方法。结果 膜吸附-超滤法、膜吸附-PEG法和膜吸附法回收率均值分别为19.80%±12.19%、12.71%±9.09%和9.05%±4.89%,各因素对回收率的影响顺序为:膜吸附-超滤法>膜吸附-PEG法>膜吸附法;高浓度>低浓度。混合纤维素酯膜的富集效果优于尼龙膜。100 K和50 K的超滤管富集效果无差异。硅胶离心柱法和磁珠法核酸提取效果无差异。结论 通过二次富集可提高富集效率,膜吸附-超滤法优于另两种方法,且其操作简单、耗时短、对设备依赖性低,易于推广。膜吸附-超滤法的实验条件仍可优化、完善,拓展其在不同水体和不同病毒富集中的应用。     

益生菌延长秀丽隐杆线虫寿命分子机制研究进展

益生菌通过改善宿主肠道微生态平衡,抵抗有害菌,增强宿主黏膜屏障完整性及免疫调节等多种作用机制对宿主健康产生有益作用。秀丽隐杆线虫(简称线虫),因生命周期短以及具有保守的调节宿主寿命的信号通路和宿主防御机制,而成为宿主-微生物相互作用和衰老研究的理想模型。本文总结线虫中益生菌通过作用于常见的分子信号通路,如胰岛素(IIS)、p38丝裂原激活蛋白激酶(p38 MAPK)和压力应激等,发挥抗衰老作用的研究进展,为开发益生菌菌株提供新的见解。     

影响文胸产品美观性的主要因素

通过真人试穿试验,对目前市场上有代表性的3款文胸进行了美观性评价,获得了专家及试穿者对文胸美观性评价的主观数据;此外,利用三维人体扫描仪对分别穿着3款文胸的试穿者进行扫描,获得相关的客观数据;最后运用数理统计的方法,对文胸美观性主观评价数据和扫描获得的穿着不同款文胸时胸部形态数据进行综合分析,提取影响文胸美观性的主要因素。通过对主观评价结果的分析,得出文胸的塑型效果和文胸款式是影响文胸美观性的两个重要因素;通过对试穿者试穿3款文胸时胸部形态的数据的分析,得出胸高和胸高与胸长比值是影响胸部形态的两个重要因素。     

关于机械化深松有关问题的探讨

介绍了机械化深松的作用、进行机械化深松作业的条件及要求,阐述了机械化深松机具的使用以及保护性耕作地块的深松.     

传感器网络节点随机调度算法的覆盖度分析

节点随机调度算法,是一种研究网络局部覆盖的重要方法,它无需知道节点位置信息、简单易用并有较高的实用价值。但是目前对该算法的研究成果均是基于布尔感知模型设计。布尔感知模型尽管简单,但不能真实地反映节点的感知能力。文中首次在概率感知模型下,分析了随机调度算法中网络覆盖度与节点数之间的关系,给出了节点数的下界值,并通过仿真验证了分析的正确性。     

广西钦州保税港区二号路主卡口结构设计

本文通过广西钦州保税港区二号路主卡口工程结构分析表明,其结构的周期、位移以及承载力均满足规范要求,并总结了结构设计中采取的构造措施,可供类似工程参考.     

Rapid detection of Vibrio parahaemolyticus strains and virulent factors by loop-mediated isothermal amplification assays

A loop-mediated isothermal amplification (LAMP) method for rapid detection of the foodborne Vibrio parahaemolyticus strains and related virulent factors had been developed and evaluated in this study. Six primers, including outer primers, inner primers, and loop primers, were specially designed for recognizing 8 distinct sequences on 3 target genes, which were tlh, tdh, and trh. The detection limits were found to be 100, 100 fg, and 1 pg DNA/tube for tlh, tdh, and trh, respectively. Application of LAMP assays were performed on 368 foodborne V. parahaemolyticus strains, the sensitivities of LAMP assays for the tlh, tdh, and trh were 100, 95.6, and 96.4%, and the negative predictive values (NPV) were 100, 84.7, and 93.1%, respectively; with a 100% specificity and positive predictive value (PPV) for all 3 target genes.