基于并联神经网络的烤烟内在质量分析方法

提出了一种并联神经网络，能直接将烤烟主要化学成分测量数据转换为与香气，吃味，杂气，刺激性等人的感官评定指标相一致的结果。该方法不必预先假定数学模型，较常规数据处理方法有更广泛的适用性。应用实例表明，与感官评定方法相比，该方法在客观性，准确性等方面有显著出优越性。     

水中总氮的测定预处理方法改进

采用COD消解管和COD消解仪代替标准方法中具塞比色管和高压灭菌器进行消解，调整了取样体积，减少了碱性过硫酸钾加入量和其中氢氧化钠的用量.试验结果表明，改进预处理方法后绘制的标准曲线，相关系数为0.999 5，检出限为0.05 mg/L，相对标准偏差小于5%，样品加标回收率为98.0%~102%.与标准方法相比，改进后的方法精密度和准确度都有一定的提高，并且分析时间缩短，过程得到简化.改进后的方法和标准方法进行t检验比较无明显差异，可满足水中总氮的快速、准确测定.     

卤代化合物的碳—13化学位移模拟

用人工神经网络和多元回归方法对含２个碳的２１个卤代化合物的３５个化学位移进行计算机图像模拟，结果表明，人工神经网络方法优于多元回归方法，同时此种方法处理这类问题有明显的优势，波谱模拟技术在有机化合物结构解析中是非常有用的方法。     

三元络合物分光光度法测定微量元素锗

介绍了用三元络合物分光光度法测定粮食，植物，药材中微量锗的方法，方法简单，快速，适合基层实验室采用。     

NH_2基态和激发态的SAC－CI和量子拓扑方法研究

ＮＨ_２基态和激发态的ＳＡＣ－ＣＩ和量子拓扑方法研究郑世钧，蔡新华，宋天乐，孟令鹏，中迁博，波田雅彦（河北师范学院化学系，石家庄，０５００９１）（京都大学工程学院京都，日本）关键词ＳＡＣ－ＣＩ方法，激发态，电子密度，拓扑分析用量子拓扑学方法研究激发态...     

氯化亚锡还原-硫氰酸铵快速光度法测定合金钢中的钨

建立了氯化亚锡还原－硫氰酸铵快速光度法测定合金钢中钨的方法，方法的线性范围为2－400μg/50mL，相对标准偏差为0．24％－1．22％，方法简便，快速，测定结果准确。     

重力场热力学分析和重力化学势

用分析比较的方法对重力场热力学作了新思考，建立了重力场中的Ｇｉｂｂｓ方程和重力化学势，使处理方法简单通用，与普通热力学方法衔接起来，应用大为方便。     

有限元方法在量子化学中的应用

简述了有限元方法发展的历史，介绍了有限元方法在量子化学中的应用现状，详细讨论了有限元方法在量子化学计算中的优点、存在的困难，以及解决问题的可能途径，并指出了最新发展动向。     

褶合光谱法测定肌苷口服液中的肌苷含量

建立褶合光谱法测定肌苷口服液中肌苷含量的方法。方法的线性范围为6.00-14.00μg/ml，线性回归方程为Qj=0.004233c-0.002597，相关系数r=0.99999，平均回收率为99.99%，RSD为0.20%。t检验结果证明，该方法与吸光系数法之间无显著性差异。该方法简便、快速，用于实际样品分析，结果准确、可靠。     

iR降近于零的长光程薄层光谱电化学池的设计

ｉＲ降近于零的长光程薄层光谱电化学池的设计庞代文，王宗礼，张敏（武汉大学化学系，４３００７２）光谱电化学方法是光谱方法与电化学方法的有机结合，已成为将电化学研究层次提高到分子水平的强有力的手段。实现此方法的前提是先设计出简单方便的电化学接口，即光谱电...     

液液萃取-GC-MS法测定水中硝基苯质量控制指标研究

采用液液萃取–气相色谱–质谱法测定水中硝基苯,通过统计全国多家实验室的测定数据,对平行样测定结果相对偏差、空白加标回收率、样品加标回收率、空白加标回收率相对偏差及样品加标回收率相对偏差5个质控指标进行分析,得出质控指标评价标准。在概率P,γ均为0.90时,平行样测定结果允许最大相对偏差应控制在11.0%;当空白加标浓度为0.2～30μg/L时,回收率控制范围为59%～113%;当样品未检出、加标浓度在0.25～50μg/L时,样品加标回收率控制范围为56%～110%;空白加标、样品加标回收率最大相对偏差应分别控制在10.0%和11.1%。在概率P和γ均为0.95时,平行样测定结果允许最大相对偏差应控制在13.5%;当空白加标浓度为0.2～30μg/L时,回收率的控制范围为50%～122%;当样品未检出、加标浓度在0.25～50μg/L时,样品加标回收率控制范围为49%～117%;空白加标、样品加标回收率最大相对偏差应分别控制在12.6%和14.6%。     

Measurement of near zero concentration: recording and reporting results that fall close to or below the detection limit

Issues relating to the recording and reporting of analytical data obtained where the concentration of analyte is around or below the detection limit are discussed. The following recommendations are proposed. Analytical results should be recorded by the analyst exactly as they occur, including any negative results, and such records retained for an appropriate length of time. For the purposes of quality assurance in the laboratory (including method validation, internal quality control, and proficiency testing), negative results should be used as they stand. Analytical results reported to a customer should be accompanied by a statement of uncertainty including, in the present context, uncertainty at low concentrations of analyte. The method of editing of reported results must be a contractual matter between the analyst and the customer, but a statement of the procedure used should accompany the results and should be explicit. Normally such editing should be restricted to setting negative results to zero. The customer should be encouraged to pass on the statement to all end users. Data intended for the public domain should be accompanied by a statement detailing the uncertainty, the method of editing, and the location of the unedited data. Most types of statistical processing of datasets containing low concentrations of analyte should be undertaken on the unedited data.     

液体样品对核磁图谱质量影响因素探讨

结合样品核磁测试结果,以具体实例的形式,总结了核磁样品分析的基本要求,分析了核磁管和氘代试剂的选择、样品制备及pH值等因素对核磁测试结果的影响,并提出了样品最优测试条件:核磁管管体内外表面要足够光洁均匀,在高温条件下,优先选用升温核磁管.尽量选择小支封装氘代试剂,降低水峰的影响,并且应考虑样品的性质,避免试剂与测试样品发生反应.样品必须与溶剂充分混合均匀,样品量要在溶液粘度与灵敏度之间做好平衡.在分析与氧、氮和硫共价相连的氢原子时,应该选择恰当的pH溶液.以上研究结果可以为其它样品核磁测试提供借鉴指导.     

Quality assurance and instrumentation

 The quality process for commercial analytical equipment starts with the selection of the vendor. It is recommended that vendors be selected who are recognized as having quality processes in place for instrument design, development, manufacturing, testing, service, and support, for example, ISO 9001 registration. When the instrument arrives in the laboratory, the installation process should follow well-documented procedures. This includes a visual inspection that the instrument is not damaged and checking that the instrument, documentation and accessories such as cables and tubings are complete. Before the instrument is used it should be verified that it meets functional and performance specification. During operation the instruments should be periodically inspected and tested, verified to meet performance, and calibrated. The instrument should be labeled with the calibration status, indicating the dates of the last successful and the next performance verification and calibration. Defective instruments should be removed from the testing area or should at least be labeled as being "out of order." Received 23 August 1995 Accepted 6 September 1995     

Environmental and resource aspects of sustainable biocomposites

This review critically discusses the environmental and resource implications for the design of sustainable biocomposites. Sustainable biocomposites should satisfy several requirements: (i) renewable and/or recycled resources should be utilized for their manufacture; (ii) the synthetic, modification, and processing operations should be benign and energy effective; (iii) no hazardous environmental or toxicological effects should arise during any stage of their life cycle; and (iv) their waste management options should be implemented. The future integration of biorefineries and green chemistry will guarantee the availability of a wide range of raw materials for their preparation. The emission of volatile organic compounds and the release of nanoparticles should be evaluated from a toxicological and environmental point of view. Finally, the susceptibility of sustainable biocomposites towards degradation, including abiotic effects (water absorption, thermo- and photo-oxidation) and biofilm formation and biodegradation, must be considered, to guarantee their structural and functional stability during service life, and to ensure their biodegradability and assimilation during composting.     

Optimal conditions for the reversed-phase chromatography of proteins

Summary Optimum stationary phases for reversed phase chromatography should be based on a silica with a large average pore diameter, preferably above 30nm. To exclude anormalous elution behaviour of proteins, octadecyl groups should be bonded to the surface and the residual silanol groups should be reacted with a highly active silanization agent like bistrimethylsilyl acetamide. The total amount of bonded carbon should not exceed 5% w/w. Because of the low diffusion coefficients of proteins, the particle diameter should be as small as possible. Protein retention can hardly be influenced by changes of the organic modifier or by temperature. Because of solubility and viscosity, however, acetonitrile is to be prefered. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

直读光谱法测定钢铁中常规元素结果准确性的探讨

为提高ARL 4460直读光谱仪测定钢铁中8种常规元素分析结果的准确性,对一些主要的影响因素特别对碳及硫量测定的影响因素做了试验,并对其结果作了探讨,从中得到了一些有利于提高测定准确性和精密度的方法和措施,主要有以下几点:①改变了仪器出厂时设定的光源参数(冲洗时间由10s降为2s,预燃时间由7s降为6s,曝光时间由8s降为3s);②测定碳、硫、磷须用99.999%的高纯氩,且应控制其压力在0.30 MPa左右;③试样表面要干净平整,纹路清晰,应用细砂砂轮机处理试样表面;④制备定碳样品时,样品温度不能高于40℃,且保持其起始状态的纹路粗细程度;⑤分析室环境温度应保持恒定(25℃左右),每8h进行一次工作曲线的校正;⑥测定硫的试样若温度过高,宜先将其冷却至接近室温再作分析,且在分析时应至少取3个分布均匀的激发点,且需根据试样特点作现场校正曲线,用控制试样进行类型标准化。     

总氮测定过程中空白吸光值偏高的原因分析

使用HJ 636-2012测定水质总氮时,空白吸光值往往偏高.为了寻找最佳的实验条件,使用多元线性回归模型定性评价过硫酸钾和氢氧化钠的纯度、实验用水、碱性过硫酸钾溶液的存放时间、消解条件、冷却时间、消解器皿等因素对空白吸光值的重要性.结果表明:过硫酸钾纯度对空白吸光值影响最显著.为了保证总氮空白吸光值小于0.030,测...     

扫描电子显微镜对样品的要求及样品的制备

扫描电子显微镜对样品的要求很严,要求样品必须是固体,且做到五无:无毒、无放射性、无污染、无磁、无水分,成分稳定,块状样品大小要适中,粉末样品要进行特殊处理,对不导电和导电性能差的样品要进行镀膜,且要选择适当的镀膜仪,方能达到理想的分析效果.     

Inorganic Crystal Structure Data to be Presented in a Form More Useful for Further Studies

To make inorganic structure data more useful for further studies a five-point list of simple procedures to be followed by authors of crystal structure papers is proposed. 1. A crystal structure should be described with the space group corresponding to its true symmetry. 2. A new structure proposal should be tested, if it is realistic in principle. 3. A structure should be described with a space group in a setting given in the International Tables. 4. For a comparison with other structures the structure data should be standardized with the program STRUCTURE TIDY. 5.“New” structure data should be checked in the databases, Chemical Abstracts or on-line intemet resources, if they are really new. The list is supplemented with many explanations, commentaries, examoles and references.