A Method of Quantitative Measurement of Fluorescence Intensity by Confocal Laser Scanning Microscopy

We present a method of quantitative measurement, by laser scanning microscope, of intensity of fluorescence in assays on concentration of fluorochromes in a sample. This method can be used to evaluate the DNA content or the concentration of any protein, marked by an appropriate fluorescent dye, in single cells or groups of cells, isolated or in a tissue. Confocal laser scanning microscopy provides optical serial sections through thick biological sample that give accurate information about the intensity of fluorescence. The method we propose consists in scanning the sample by juxtaposition of optical sections and displaying it as a suitable projection. Multiplying the fluorescence intensity in such projection by the number of sections we obtain an estimate of the concentration of fluorochrome in the sample. We tested this method on fluorescent beads and on biological samples stained for DNA. We evaluated and corrected the measure for the photobleaching effect and for the beam theoretical distortion. Our results show that this method is accurate and suitable to compare samples of variable thickness and for multiple stained samples, and is less time consuming than the method based on the scanning of the sample according to the Nyquist principle.     

连翘苷的共焦显微拉曼光谱与普通拉曼光谱

目的：分别采用共焦显微激光拉曼光谱仪和普通拉曼光谱仪测定连翘苷对照品固体粉末的拉曼图谱,对比两种仪器所获得的图谱,总结两种拉曼光谱的优缺点。方法：采用RM-1000型共焦显微激光拉曼光谱仪和国产某型号激光拉曼光谱仪检测连翘苷对照品粉末的拉曼谱图,对其拉曼图谱进行比较并对结果进行分析。结果：两种拉曼光谱中均显示出了连翘苷的主要拉曼特征峰,可以用于定性鉴别;普通拉曼光谱图未显示出连翘苷的指纹峰,且其拉曼峰强明显弱于共焦显微拉曼图谱。结论：采用共焦显微激光拉曼光谱仪用于连翘苷的定性研究比普通拉曼具有明显优势,可以用于中药有效成分的鉴别。     

A Precision Device for the Positioning of the Probe in Scanning-Probe Microscopy

A device for positioning of a probe over an area of 1000 × 1000 m with an accuracy of 1 m is described. The device is compatible with scanning-probe microscopes available from the NT-MDT Co. (Zelenograd, Russia). It is shown that the device can be used for the examination of large objects and objects with highly developed surface topography.     

一个自动扫描电子显微镜系统方法

扫描电子显微镜对于材料研究来说是一个很好的工具,该工具在较大扫描尺度上需要在人工操作下探索材料的形貌和组成.当前其发展重点是:通过无需仪器设置的完全自动的仪器操作方法快速地检测出大量的不同性质的样品,例如颗粒样品.技术领域的不断创新与仪器领域关键区域的革新带来一个新层次的操作,其具有的可靠性和准确性开创了一个新的应用领域.     

Measured Viscous and Dry Friction Forces in Nanometer-Thick Lubricant Film by Friction Force Microscopy with Micromechanical Probe

A new method for measuring the contribution of the local viscous and dry friction forces on the micrometer scale is described. The velocity dependence of the local friction force is obtained using a dual-axis micromechanical probe with an electrostatic actuator. It is used to obtain the local damping coefficient and dry friction force of nm-thick lubricant films patterned on the micrometer scale. This method is useful for clarifying the mechanism of thin-film-based and boundary lubrications.     

现代人才观念新探

现代人才观念的特征、结构和内容     

Effect of Oxygen Adsorption on Adhesion of W to Au Studied by Field Ion Microscopy

A field ion microscope has been used to investigate the influence of oxygen adsorption on adhesion of W to Au. An adhesion contact in ultrahigh vacuum of the field ion microscope was carried out using a W tip either with or without oxygen adsorption. It was found that adhesion force decreased with increasing oxygen exposures up to 60 Langmuirs (L). With an oxygen exposure of 16 L, an intermediate adhesion resulted. Adhesion is thus dependent upon the coverage of oxygen. The depth of adhesion-induced lattice defects was studied using the field evaporation technique. Over 200 L, adhesion force was not detectable, nor was distortion of W atoms.     

Multivariate Statistical Techniques to Determine Essential and Toxic Elements in Biological Samples by X-Ray Fluorescence

X-ray fluorescence spectrometry was used to determine essential and toxic elements in tea leaves. Quantitative measurements were obtained for K, Mg, Cu, Zn, As, Sr, Fe, Co, Ca, P, S, Pb, Rb, and Mn. Pearson's product moment correlation coefficient with principal component analysis and hierarchical clustering analysis were performed to investigating the relationships between essential and nonessential elements in the dry herbal mass. From multivariate statistical analysis, Ca, Fe, P, Zn, and Mn were found to have strong positive correlations. While principal component analysis demonstrates that tea leaves were dominated by Fe and Cl in the first principal component, Pb and As were in the second principal component with cumulative variability of 84.4%. However, hierarchical clustering analysis indicated the presence of a cluster of four essential elements, one cluster containing toxic and essential elements, and one cluster composed of toxic elements. The results of this study improve understanding of the correlation between essential and toxic elements in biological samples such as tea leaves.     

氢化物原子荧光法测定水中硒优化条件选择

参考我国卫生部生活用水卫生规范及检验规范，采用模糊正交设计法，建立氢化物原子荧光法测定水中硒的优化实验方法。根据实验优化条件进行水中硒测定，硒浓度在0-0．20mg／L范围内有良好线性关系，r=0．9997，检出限为0．78μg／L，相对标准偏差为2．396～7．9％，回收率为96％～105％。利用该优化的实验条件进行氢化物原子荧光法水中硒测定，方法更加准确、灵敏、稳定。     

宽量程测量系统多档增益设定及实时标定方法探讨

文章对宽量程测量系统多档增益设定及实时标定方法进行了较深入的探讨，提出了在宽量程测量范围内分区间分别处理的方法，科学地解决了究竞怎样进行放大器档位的设置以及各档位放大器增益怎样确定这个长期以来困扰在测量领域的难题，在此基础上还提出了经济实用的增益实时标定方法。     

用Vizi CAD设计计算时几个问题的探讨及综合实例

本文先介绍了ＶｉｚｉＣＡＤ有限元软件,然后结合作用的使用经验就用ＶｉｚｉＣＡＤ６设计计算时的几个问题进行的探讨,如文件管理、建模、量纲系统、图形输等。最后,本文给出一个温度场和应力场计算的综合实例。     

冷原子吸收法测定汞标准溶液保存时间探讨

通过对冷原子吸收法测定汞所用的标准溶液保存时间的试验 ,发现汞标准液也可以和其它标液一样可以保存至少一个月 ,可为平时工作减少工作量     

Comparison of Two Methods of Methyl Group Grafting to the Silica Thin Film Surface and Its Tribological Properties Measured by Atomic Force Microscopy

Two different methods are used to modify silica surfaces and the results of the different modification methods on the frictional properties are presented in this paper. Methyl groups were introduced to the silica film directly during the synthesis step with the use of triethoxymethylsilane or by post-synthesis grafting from solution using trimethylchlorosilane. Atomic Force Microscopy (AFM) was used to compare the frictional behaviour of samples after modifiying the silica surface using the two methods. It was found, that depending on the presence of methyl groups on the surface or in bulk, the frictional properties are strongly influenced not only by methyl groups but also by elasticity of final material.     

应用探针式电容传感器检测发动机润滑油品质的研究

应用探针式电容传感器测量润滑油中固体颗粒含量的原理,是根据固、液体混合物在电容器两极板之间介质的介电常数变化而使电容发生变化。应用该原理设计出了一套润滑油油品监测系统,简称为YPT系统。应用该系统,对发动机润滑油中的铁、硅固体微粒含量变化与电容变化的相互关系进行了初步探讨,并建立起来了一种新的润滑油品质YPT评价标准。这个新的评定标准,为确定发动机润滑油的更换周期及预测发动机的使用寿命等方面的研究,提供了一种比较简便实用的科学依据。     

溅射法制备InSb薄膜工艺探索—In与Sb的原子比问题

介绍一种基于原子比为1：1的InSb靶制备原子比为1：1的InSb薄膜的方法,实验结果表明,该方法能较好地解决类似化合物溅射制膜过程中膜成分与靶偏离问题。     

数字化高灵敏度荧光显微镜在AS2O3诱导MGC-803细胞核凋亡产生钙振荡研究中的应用

利用数字化高灵敏度荧光显微镜对As2O3诱导MGC-803细胞核凋亡过程中的钙振荡进行研究,通过图像中荧光强度随时间变化的规律反应钙振荡的频率和强度变化.结果证实As2O3诱导MGC-803细胞核凋亡过程中,的确引发了钙振荡,说明核钙参与了凋亡过程,并且钙振荡的频率以低频为主.对两相邻细胞核的钙振荡信号观察分析发现,两核钙强度变化曲线低频部分异常相似,几乎在同一时刻达到最高点和最低点.尽管钙波动的幅度不同,但基本频率相同,由此可初步预测钙信号以频率变化为表达特征.两细胞核凋亡呈同步化趋势,证明在受到As2O3刺激后,细胞核的凋亡不是个别现象.     

调节方向盘转速的电动助力转向系统回正控制

针对已有电动助力转向(EPS)系统高速回正超调,低速回正不足的问题,提出了基于控制方向盘转速的回正控制策略。建立了齿条式电动助力转向系统动力学模型;阐述了回正特性曲线的获取方法;通过Adams/Simulink对控制策略进行了仿真试验。在控制策略方面跳出了以往的基于方向盘转角的模糊PID控制的局限,仿真分析表明基于方向盘转速控制的回正控制策略实现了理想的回正效果,较已有的回正控制不存在回正不足或超调现象,且回正过程无方向盘震荡现象,达到了迅速、准确的回正效果。