A novel laboratory bench for practical evaluation of catalysts useful for simultaneous conversion of NOx and soot in diesel exhaust

This study deals with the development of a laboratory bench for the practical evaluation of catalysts that are useful for the direct conversion of NO_x and soot in the exhaust of diesel engines. The employed model exhaust is generated by using a diffusion burner with additionally dosing some gaseous components to the burner gas to obtain a realistic feed composition. The produced soot is extensively characterized by employing thermogravimetry, transmission electron microscopy, N₂ physisorption and temperature programmed techniques. The results of the different characterization methods show that the present soot is suitable for the intended catalytic investigations. The simultaneous conversion of NO_x and soot is examined like in practice, i.e. the soot is separated from the tail gas by a diesel particulate filter (DPF) that is coated with the catalyst. The deposited soot is then catalytically converted by NO_x and O₂ to form N₂ and CO₂. The conversions of NO_x and soot are measured by exclusively applying gas analysers, whereby a special experimental procedure is developed to determine the soot removal. Hence, additional soot related analytics are not required. To show the suitability of the constructed bench a Pt/Fe₂O₃/β-zeolite sample is taken as test catalyst that is reported to be very active in NO_x/soot reaction. The measurements performed with and without catalyst clearly show the effect of the used sample in simultaneous NO_x/soot conversion. We therefore consider the constructed laboratory bench to be a useful tool for testing and ranking catalytic materials.     

钛及钛合金中氧和氢的联合测定

叙述了用红外吸收法对钛及钛合金中氧和氢联合测定的方法，取得了测定的最佳条件。连续测定6次的相对标准偏差在10％以下，作加标回收试验的回收率为95．6％～103．9％。分析时间在3min以内，可应用于日常分析，结果满意。     

Experience with Siberian Centralized Dispatch Regulation regarding location determination of damages sustained by intersystem high-voltage transmission lines

A set of measures that can be implemented by the Relay-Protection and Automated-Equipment Service for Centralized Dispatch Regulation (CDR) in Siberia to determine the location of damage sustained by inter-system 550-and 220-kV transmission lines maintained by the United Power System (UPS) of Siberia, and the methodology and technology of damage-location determination (DLD) are described. The damage sustained by the 500-kV high-voltage lines (HL), and the accuracy of DLD relative to zero-sequence emergency parameters are analyzed statically. __________ Translated from élektricheskie Stantsii, No. 5, pp. 59–62, May, 2006.     

丙酰芸苔素内酯的气相色谱分析

采用毛细管柱气相色谱法,以(22E,24S) 2,22 二烯 5α 豆甾 6 酮为内标,对丙酰芸苔素内酯进行定量分析。色谱条件为12m× 0.53mm,膜厚1.5μm(CBP 1固定液)熔融石英毛细管柱,柱温为305℃,检测器、汽化室温度为320℃,载气流速为20mL/min。该方法检测丙酰芸苔素内酯质量分数的平均标准偏差为0.39%,平均回收率为100.4%。方法操作简便,定量准确。     

用双波长分光光度法同时测定锡镍合金镀液中的钴和镍

为研究新型环保锡镍合金镀液中钴和镍含量同时测定的方法,在pH=4.5的醋酸-醋酸钠介质中,采用1%tween-80增溶,经0.02%5-Br-PADAP显色,以双波长分光光度法对Co2 与Ni2 含量进行了同时测定.试验表明,Co2 、Ni2 含量在0～6μg/(25 mL)范围内符合比尔定律.该方法方便、快速、准确,结果令人满意.     

过渡金属元素催化羟自由基反应机理研究

针对显色剂－过渡金属元素－过氧化氢体系，用分光光度法间接测定羟自由基。通过大量试验，确定了三苯甲烷类酸性酚醌吡喃类为有效显色剂，并确定了溴邻苯三酚红－亚铁离子－过氧化氢体系测定羟自由基的最佳条件，首次推测出其最可能的反应机理为：亚铁离子催化过氧化氢产生羟自由基，羟自由基氧化溴邻苯三酚红上的羰基碳氧双键，破坏其显色的共轭结构，使其褪色，此法可作为筛选羟自由基清除剂的有效方法。     

食品中病原菌检测技术研究进展

介绍了许多食品安全检测新技术和新方法,包括生化检测技术、免疫学技术、PCR检测技术、生物芯片技术、传感器技术、流式细胞术和基因探针技术,并且阐述了食品安全检测技术的发展趋势,这些技术的发展将会在食品卫生检验方面起到越来越重要的作用,最终将达到预防肠道传染病和食物中毒发生的目的。     

A new amperometric biosensor for fructose determination based on epoxy-graphite-TTF-TCNQ-FDH-biocomposite

In this work a novel amperometric biosensor for fructose determination in solutions was developed. The device was constructed by the incorporation of a tetrathiofulvalene-tetracyanoquinodimethane organic conducting salt and fructose dehydrogenase enzyme, include in a polymeric matrix of epoxy resin and graphite powder. Because of the electrocatalytic function of the salt, the direct transfer of the electron between the reduced prosthetic group (PQQH₂) of the enzyme and the transducing material, was verified at a low working potential (150 mV vs. Ag/AgCl), where the interfering reactions were minimized. The response time at 90% of the steady state value was less than 20 s. The current response was directly proportional to the D-fructose concentration from 0.01 to 0.3 mmol/l with a detection limit of 0.005 mmol/l (signal/noise of 3) and a sensitivity of 1.9985 μA/mmol. The biosensor sensitivity diminishes when its surface is not polished between successive determinations, and remains constant (rsd=1.85, n=10) when the surface is polished between determinations. The effects of temperature and pH on the biosensor response were studied and analyzed; also the properties of the enzyme (Km _ap, I _max, Q₁₀) were determinate in this work. The biosensor was used to determine fructose in high fructose syrups and there were not significant differences between these results and those obtained by HPLC (p≤0.05). During 4 months, in intermittent determinations the biosensor kept 100% of its original sensitivity and after 18 months stored at 4°C, it only lost 32% of its sensitivity. The simplicity, low working potential, high stability and good performance of this biosensor shows a great potential for its use in the fructose determination.     

EASY2000色谱处理系统在酒样色谱分析中的运用

介绍了EASY2000色谱处理系统在酒类产品分析实际应用过程中的方法，步骤，特点及注意事项等。     

XRF法测定高岭土中的主次量元素

采用X射线荧光光谱法取代原有的化学法，分析了高岭土中的9种主次量元素。通过对测定条件的选择以及样品制备等方面的考察，制定出最佳分析方案。分析结果表明，该方法准确、可靠，分析周期由原来的6h缩短为10min.