氟离子选择电极法测啤酒中的氟

本文采用氟离子电极法测定啤酒中的氟 ,测量溶液的酸度为PH5— 6,用总离子强度调节缓冲液 ,消除干扰离子及酸度的影响 ,方法回收率 96.1 2 %～ 99.2 4 % ,线性范围为 1 0 - 1 mol/L～ 5× 1 0 - 7mol/L ,最低检出浓度 0 .0 1 μg/ml,本法操作简单、快速 ,适合作常规测定 .     

《河南植物志》虎耳草科补遗

报道了《河南植物志》中未记录的虎耳草科植物9种5变种(均采有标本)。     

Understanding of the influence of process parameters on the heat transfer behavior at the metal/die interface in high pressure die casting process

The current paper focuses on the influence of the process parameters on the peak values of the interfacial heat transfer coefficient(IHTC)at metal/die interface during high pressure die casting(HPDC)process.A"step shape"casting and AM50 alloy were used during the experiment.The IHTC was determined by solving the inverse thermal problem based on the measured temperature inside the die.Results show that the initial die surface temperature(IDST,TDI)has a dominant influence while the casting pressure and fast shot velocity have a secondary influence on the IHTC peak values.By curve fitting,it was found that the IHTC peak value(hmax)changes as a function of the IDST in a manner of hmax=e αTγ DI .Such relationship between the IHTC peak value and the IDST can also be found when the casting alloy is ADC12,indicating that this phenomenon is a common characteristic in the HPDC process.     

ESTIMATION OF CHAIN REACTION BANKRUPTCY STRUCTURE BY CHANCE DISCOVERY METHO—WITH TIME ORDER METHOD AND DIRECTED KEYGRAPH

Chain reaction bankruptcy is regarded as common phenomenon and its effect is to be taken into account when credit risk portfolio is analyzed.But consideration and modeling of its effect leave much room for improvement.That is mainly because method for grasping relations among companies with limited data is underdeveloped.In this article,chance discovery method is applied to estimate industrial relations that are to include companies' relations that transmit chain reaction of bankruptcy. Time order method and directed KeyGraph are newly introduced to distinguish and express the time order among defaults that is essential information for the analysis of chain reaction bankruptcy.The steps for the data analysis are introduced and result of example analysis with default data in Kyushu, Japan,2005 is presented.The structure estimated by the new method is compared with the structure of actual account receivable holders of bankrupted companies for evaluation.     

磁泡研究有新突破——在磁畴壁上读取信息

本文报告了最新重要科技信息.利用外加磁场控制布洛赫畴壁(简记BL)可产生磁化矢量复杂扭转.其中能形成一些磁化方向垂直指向膜面的小区域.称为垂直布洛赫线(或VBL).利用这些成对的布洛赫线,可以制成存储密度极高的计算机存储器,因为信息是在布洛赫线内被编码寄存的,而不是在磁泡本身内.因此,极限信息密度可达到10~(10)bit/cm~2,从布洛赫线存储器中检索信息只需要约2/1000s、而目前检索信息要10s.     

我国轿车工业面临的若干选择

本文参考了世界各国轿车工业发展的经验，在分析我国轿车工业现状的基础上，对我国轿车工业所面临的若干选择作了探索性的研究。     

微机在机械故障诊断方面的应用

本文简要地论述了利用微机对机械设备故障进行在线监测诊断的重要性，设计了AppleⅡ微机在线故障诊断系统，并以CW6140万能车床主轴箱为例给出主轴箱故障诊断结果。     

Determination of surface topography of biological specimens at high resolution by scanning tunnelling microscopy

Although techniques are available for the determination of the three-dimensional structure of biological specimens, for example scanning electron microscopy, they all have some serious drawback, such as low resolution, the requirement for crystals or for the sample to be analysed in a high vacuum. In an attempt to develop a technique for high-resolution three-dimensional structure analysis of non-crystalline biological material, we have tested the applicability of scanning tunnelling microscopy (STM), a method that has been used successfully in the analysis of metal and semiconductor surface structures. We report here that scanning tunnelling electron microscopy can be used to determine the surface topography of biological specimens at atmospheric pressure and room temperature, giving a vertical resolution of the order of 1 A. Our results show that quantum mechanical tunnelling of electrons through biological material is possible provided that the specimen is deposited on a conducting surface.     

一种新的用于群组排序的最小平方逼近法

本文将文献[1,2]所给的最小平方逼近法推广应用于层次分析法中的群决策排序。文中对由多个判断决策者给出的多个不同的判断矩阵,提出通过求解群组判断矩阵最小平方偏差的方法得出判断矩阵的最佳排序和理想综合判断矩阵;通过对群组判断矩阵进行一致性讨论,据此又给出了一种用于群组判断矩阵排序的最小加权平方逼近法。理论分析和应用实例表明,应用最小平方逼近法和最小加权平方逼近法对群组判断矩阵进行排序是可行的和有效的。     

利用高钙复合球化剂和空气吹炼法制取球墨铸铁的研究

本文介绍了用高钙复合球化剂和干燥空气吹炼法制取球墨铸铁的试验研究情况。这种方法工艺简单、设备投资少、适于在中小铸造厂推广使用。