理化试验室仪器设备的计量管理

仪器设备计量管理的主要内容是通过不确定度、M_(cp)值计算或重复性试验判断仪器设备配备的合理性,开展仪器设备的计量检定、校验和检验,建立标志和技术档案等管理,使仪器设备始终处于正常的工作状态。     

理化试验室的分析质量评价

化学计量是理化试验室分析质量保证的基础,没有化学计量,也就没有分析质量保证。本文从五个方面对理化试验室的分析质量评价工作进行了论述。     

化学计量在产品质量保证中的重要作用

阐述在化学分析中,由于增强了化学计量意识,满意地解决了粘胶基碳布质量问题,显示出化学计量在产品质量保证中的重要作用。     

质量控制图的修正及其在化学计量测试中的应用

质量控制图是制造业控制产品规格质量过程中经常使用的一项技术工具[1],等同采用ISO 8258-1991的GB/T 4091-2001《常规控制图》[2]中提供了常规控制图的绘制方法。近年来,随着对化学分析测试过程质量控制要求的不断提高,起源于制造业的GB/T 4091-2001广泛被检测实验室用于分析和控制测试系统的稳定状态。但因制造和分析测     

化学计量中的质量保证

从化学计量的特点出发,根据测量保证原理的基本要求,简述了化学计量中保证量值准确可靠的几个重要环节的过程控制。     

化学计量检定管理信息系统

介绍了一种以计算机关系型数据库作为开发平台研制开发的 ,应用于化学计量检定工作管理的管理信息系统。该系统能方便、快捷地检索、统计、汇总和打印下属工厂的信息及各种计量器具的受检情况     

化学计量有助于液相色谱最佳化

介绍高效液相色谱(HPLC)采用联用技术和化学计量方法,从而使色谱分离获得最简单、最佳实验条件     

化学计量及分析测试技术发展动态

介绍国内外标准物质、分析测试技术的发展状况,重点介绍了美国、加拿大近几年在痕量有机分析、光谱化学分析、高准确度库仑分析、电感耦合等离子质谱、炉内原子化等离子体发射光谱等方面的研究动态。     

A LASER FLASH KINETIC SPECTROPHOTOMETRIC EXAMINATION OF THE DYNAMICS OF SINGLET OXYGEN IN UNILAMMELLAR VESICLES

Abstract— The kinetic properties of O₂(₁Δ_g) have been examined in unilamellar vesicle dispersions composed of didodecyldimethylammonium bromide, di- n -octadecyl phosphate and egg lecithin. Light absorbing sensitizers 2-acetonaphthone, methylene blue and a methylene blue derivative of enhanced water-solubility were used. The rate parameters for singlet oxygen were monitored by observing the time profile of the bleaching of the reactive substrates diphenylisobenzofuran and anthracene dipropionate. The natural lifetime of O₂(₁Δ_g) in D₂O-based suspensions was shown to be 46/JS in good agreement with that found earlier for D₂O alone and D₂O-based micelle systems. The bimolecular rate constants for reaction with diphenylisobenzofuran and dimethylindole (both lipid-bound) and histidine (water-bound) were also in close conformity with the values found earlier in micellar media. Kinetic spectrophotometry has been shown to be a useful technique for examining rate parameters in these heterogeneous media.     

COMPARTMENTALIZATION OF ZINQII) TETRAPHENYLPORPHYRIN IN A HYDROPHOBIC MICRODOMAIN OF AN AMPHIPHILIC POLYELECTROLYTE: A PHYSICOCHEMICAL MODEL OF BIOLOGICAL METALLOPORPHYRIN SYSTEMS

Abstract— Small mole fractions of zinc(II) tetraphenylporphyrin (ZnTPP) moieties were covalently incorporated into amphiphilic polysulfonates having bulky hydrophobic groups such as lauryl, cyclododecyl, and (2-naphthyi)methyl (Np) groups in their side chains. The ZnTPP moieties are "compartmentalized" in the hydrophobic domains of these amphiphilic polyelectrolytes in aqueous solution. For comparison, the ZnTPP moieties were covalently incorporated into a polysulfonate without hydrophobic groups. The ZnTPP moieties in this reference polymer are exposed to water in aqueous solution. The compartmentalized ZnTPP systems in aqueous fluid solution emitted phosphorescence and thermally activated delayed fluorescence at room temperature. This is due to an extremely long-lived triplet excited state in the compartmentalized systems at room temperature in aqueous solution, e.g. 19 ms for ZnTPP compartmentalized in Np domains, compared with 3 ms for ZnTPP in the reference polymer. These remarkable compart-mentalization effects may be attributed to a restriction of motional freedom of the ZnTPP moiety isolated in a rigid and hydrophobic microenvironment provided by the amphiphilic polyelectrolytes in aqueous solution.     

PRELIMINARY EXAMINATION OF THE CONCURRENT SYNTHESIS OF METHANOL IN SLURRY PHASE

本文报道了ｌ升浆液搅拌釜内一体化甲醇合成反应过程中涉及的甲醇连续羰基化、甲酸甲酯氢解和低温甲醇合成反应的初步考察结果。     

晶体中离子的电子极化率的新计算法

极化效应对晶体的宏观性质影响很大,人们对它进行了大量的研究工作。利用Lorentz公式确定分子极化率的方法已较为成熟,但是该方法只能给出分子、元胞和键体积等单位体积的极化率,在这些单位体积中至少包括两种离子,所以它不能确定每个离子的极化行为。为了求得离子的电子极化率曾提出过许多近似方法,如假定阳离子极化小,它和自由状态差别不大,主要是阴离子极化,故用自由状态阳离子的极化率代替其在晶体中的极化率进而求     

APPLICATION OF 2D-NMR TECHNIQUES IN THE STRUCTURE DETERMINATION OF HYPODEMATINE

An alkaloid with a novel structure,named Hypodematine,was isolatedfrom Hypodematium sinense Iwatsuki(belonging to Thelypterdaceae).Itsstructure was elucidated by means of the ~1H-~1H COSY' ~1H-~(13)C COSY and long-range~1H-~(13)C COSY spectroscopy to have the skeleton of benzo-aza-cyclooctatetraenewith a phenyl substituent.Such basic structure has not been found in the na-tural product before.     

A STUDY OF CHLOROPHYLL FLUORESCENCE IN VIVO BY A FLOW METHOD

Abstract— A flow method has been devised for the study of fluorescence transients during the induction period of photosynthetic systems. The principle of transformation of time-transients into space-transients is quantitatively worked out and the characteristics and mode of operation of the apparatus is described and illustrated with experimental results.
With this method spectroscopic and kinetic investigation of in vivo chlorophyll fluorescence have been undertaken. The fluorescence emission can be split into two componmts—a variable part and a constant part—with different spectral distributions. The excitation spectrum of the light induced fluorescence changes shows that the variable part is sensitized by system 11, whereas the constant part mainly sensitized by system II has a small component originating from system I. The light-induced fluorescence change decays in darkness with half-time of about 10 ^-2 s; this decay is highly sensitive to the action of inhibitors of oxygen evolution.
The flow method can be extended to measurements of oxygen, luminescence, absorption differences. It permits using high-intensity analytic beams with no actinic action; it is well suited for the integration of low level signals.     

APPLICATION OF TIME-RESOLVED DIFFUSE REFLECTANCE TECHNIQUES IN STUDIES OF REACTION INTERMEDIATES IN SUSPENSIONS OF BACILLUS SUBTILIS

Short lived reaction intermediates such as triplet states and free radicals can be detected in vivo using laser photolysis techniques with time-resolved diffuse reflectance detection. This novel approach is illustrated for bacterial suspensions of Bacillus subtilis.     

A METHOD FOR THE CORRECTION OF QUANTUM YIELDS OF FLUORESCENCE IN SOLUTIONS

Abstract— The correction factors due to the overlap of absorption and emission spectra have been calculated for various concentrations of fluorescein dye at pH 12 by using the experimentally obtained value of apparent molar absorptivity, ε₂, for the fluorescence radiation. The observed fluorescence intensities for the same-surface detection for a given geometry have been corrected for the secondary emission effect thus calculated, and also for refraction and dilution effects, to give corrected relative quantum yields for the solutions. These have been converted to the absolute values by comparison of the integrated fluorescence quantum spectrum of a dilute solution of fluorescein with that for quinine sulphate in 0.1 N H₂SO₄. The corrected quantum yields compare well with values given in the literature.     

食品中氯丙醇测定方法研究进展

对食品中氯丙醇的检测方法进行了探讨,包括气相色谱法、气相色谱-质谱联用法、顶空-气相色谱法等,并针对样品处理所用衍生化方法作了详细介绍及对比。