Pressure and temperature effects on the excess deuteron and proton conductance

The limiting molar conductances ° of deuterium chloride DCl in D₂O were determined as a function of pressure and temperature in order to examine the proton-jump mechanism in detail. The excess deuteron conductances °_E(D ⁺), as estimated by the equation [°_E(D ⁺) = °(DCl/D ₂ O) – °(KCl/D ₂ O)], increases with an increase in the pressure and temperature as well as the excess proton conductance [°_E(H ⁺) = °(HCl/H ₂ O) – °(KCl/H ₂ O)]. The isotope effect on the excess conductances, however, depends on the pressure and temperature contrary to the model proposed by Conway et al.: °_E(H ⁺)/°_E(D ⁺) decreases with increasing pressure and temperature. The magnitude of the decrease with pressure becomes more prominent at lower temperature. These results are discussed in terms of the pre-rotation of adjacent water molecules, the bending of hydrogen bonds with pressure, and the difference in strength of hydrogen bonds between D₂O and H₂O.     

电位滴定法测定模拟高放废液中的游离酸

本文研究了用电位滴定法测定模拟高放废液中游离酸的方法。用草酸钾做络合剂以消除Ｆｅ＾３＋、Ａｌ＾３＋、Ｎｄ＾３＋等多种水解离子的影响，用标准碱直接进行电位滴定，即可快速准确地测定模拟高放废液中游离酸的含量。方法的相对标准偏差为１．８％，标准加入回收率为１００－１０１％，能为放射性废物固化试验提供可靠的分析数据。     

XPS investigations of ink‐jet printed paper

Different ink‐jet printed paper materials were investigated using X‐ray photoelectron spectroscopy (XPS) yielding the elemental composition of the near‐surface region of the papers. We found significant differences with respect to the detected elements and their atomic concentrations in the different inks studied here. Two different groups of inks could be identified by means of a lower ratio of the O and C atomic concentrations and lower concentrations in specific trace elements like Mg, Na and Si. High‐resolution spectra of C 1s and O 1s core levels allowed a detailed determination of the chemical state of the respective elements. On the basis of a detailed deconvolution of these XPS signals, significant differences between all the investigated ink‐jet printed papers were found, thereby allowing their discrimination. The applicability of the measurements and, more generally, the XPS technique for forensic investigations of paper are discussed. Copyright © 2007 John Wiley & Sons, Ltd.     

固体基质室温燐光法测定L-色氨酸

本文提出在Na_2 CO_3存在下,以NaI为重原子微扰剂,以滤纸为基质的L-色氨酸的室温燐光(RTP)测定法。本法不需通干燥气体,工作曲线的线性范围较宽,用于谷物试样分析,得到了满意的结果。     

X射线荧光光谱滤纸片法测定矿石中的铜

我们用Ｘ射线荧光光谱滤纸片法分析了古今１３铜矿石样品中的铜含量，测量结果与化学法一致。此法不需要铜矿石的标样，而且手续简单，方便，检出限低，灵敏度高，测量结果正确可靠，是分析矿石中单一或几个元素的含量较好的方法之一。     

兖州高硫煤的加氢热解脱硫及脱硫动力学

在加压热天平上，考察了氢气和氮扬气氛下高硫煤的热解脱硫。利用气相色谱在线分析研究了硫化氢氢气的逸出规律。结果表明，加氢热解比氮气下的热解有着更显著的脱友作用，脱硫率可达９０％以上。而且加氢热解下６５％的脱除硫转化为气相硫化氢，而氮气下热解是有８０％的硫转化为液相。     

Nanoscale organization of the pathogen receptor DC-SIGN mapped by single-molecule high-resolution fluorescence microscopy.

DC-SIGN, a C-type lectin exclusively expressed on dendritic cells (DCs), plays an important role in pathogen recognition by binding with high affinity to a large variety of microorganisms. Recent experimental evidence points to a direct relation between the function of DC-SIGN as a viral receptor and its spatial arrangement on the plasma membrane. We have investigated the nanoscale organization of fluorescently labeled DC-SIGN on intact isolated DCs by means of near-field scanning optical microscopy (NSOM) combined with single-molecule detection. Fluorescence spots of different intensity and size have been directly visualized by optical means with a spatial resolution of less than 100 nm. Intensity- and size-distribution histograms of the DC-SIGN fluorescent spots confirm that approximately 80 % of the receptors are organized in nanosized domains randomly distributed on the cell membrane. Intensity-size correlation analysis revealed remarkable heterogeneity in the molecular packing density of the domains. Furthermore, we have mapped the intermolecular organization within a dense cluster by means of sequential NSOM imaging combined with discrete single-molecule photobleaching. In this way we have determined the spatial coordinates of 13 different individual dyes, with a localization accuracy of 6 nm. Our experimental observations are all consistent with an arrangement of DC-SIGN designed to maximize its chances of binding to a wide range of microorganisms. Our data also illustrate the potential of NSOM as an ultrasensitive, high-resolution technique to probe nanometer-scale organization of molecules on the cell membrane.     

MgO•3B2O3-18%MgSO4-H2O过饱和溶液析出固相组成和机理研究

针对青藏高原盐湖卤水析盐过程的特点, 模拟合成MgO•3B₂O_3-18%MgSO_4-H₂O过饱和溶液, 在150 ℃水热条件下对析出固相进行研究. 用化学分析方法、X射线衍射、红外光谱进行物相鉴定. 提出了可能的结晶反应机理, 分析了水热温度对析出物相的影响及MgSO₄对硼酸镁盐的盐溶效应随水热温度的变化.     

Effect of pressure on the solubilities ofo-,m- andp-xylene in water

The solubilities of o-, m- and p-xylene in water were measured at 25.0°C up to 250, 385, and 50 MPa, respectively. The solubility increased with increasing pressure up to 120 MPa (50 MPa for p-xylene) and then decreased. The reaction volumes, V^o accompanying the dissolution at 0.1 MPa were estimated as –3.6±0.5, –3.4±0.5, and –4.1±0.5 cm³-mol^–1 for o-, m-, and p-xylene, respectively, from the pressure dependences of the solubilities. The limiting partial molar volumes, of p- and o-xylene in water under high pressure were estimated from V^o and the molar volume of the xylene. The partial molar volumes decreased with increasing pressure. The reaction volume for the formation of intra-molecular pairwise hydrophobic interaction between the methyl groups, as proposed by Ben-Naim, is discussed for the V^o of p- and o-xylene at 0.1 MPa.