钼蓝分光光度法快速测定硅在硅铝钙钡合金中的应用

将经典的氟硅酸钾沉淀碱滴定法改为钼蓝分光光度法快速测定硅。试样熔融酸化浸取，定容后，在0．15—0．6mol／L的微酸性溶液中，钼酸铵与硅酸作用生成黄色硅钼络离子，以草酸配位铁使溶液透明并破坏磷、砷等元素与钼酸铵生成的杂多酸，消除其干扰。用硫酸亚铁铵还原剂将生成的黄色硅钼络离子还原为硅钼蓝，其蓝色的强度与硅含量成一定比例关系，借此可用分光光度法测定硅含量，方法选择性强，且缩短了分析周期。     

钼蓝光度法快速测定高碳铬铁中的硅

将经典的高氯酸脱水重量法测定硅改为以碱性熔剂过氧化钠,在高温条件下熔融酸化处理试样后定容,在C（H^＋）=0．1～0．6mol／L酸度时,加入钼酸铵与正硅酸生成硅钼杂多酸（硅钼黄）,用草酸配位铁使溶液透明并破坏磷、砷等元素与钼酸铵生成的杂多酸消除干扰。用硫酸亚铁铵还原硅钼黄为硅钼蓝,测量吸光度求得硅量。方法操作简便、快速,分析结果准确,缩短了分析周期,提高工效24倍。     

分光光度法测定分子筛中的磷

采用磷铋钼蓝光度法建立了测定分子筛中磷含量的新方法。方法基于在１．２ｍｏｌ／Ｌ高氯酸介质中，磷（Ⅴ）、铋（Ⅲ）、钼（Ⅵ）形成杂多酸后，籍抗坏血酸还原形成杂多蓝原理进行磷的测定。本体系λｍａｘ＝６９０ｎｍ，εｍａｘ＝１．９９×１０４Ｌ／ｍｏｌｃｍ，磷（Ⅴ）量在０～０．０７μｇ／ｍＬ范围内符合比尔定律。本法已成功地用于分子筛中磷含量的测定，结果良好。     

ICP光谱法测定硅锰合金中的磷

介绍了ICP光谱法测定硅锰合金中磷元素的方法。制备试样溶液，溶液的酸度控制在0．1—1．0mol／L，磷元素的分析谱线178．2nm，测量结果RSD（n=11）为0．51％-0．89％。与国标方法测定结果对照，差值均在国标允许差之内，该方法准确、快速，能够满足硅锰合金中磷元素的日常测定。     

铁矿石中低含量磷和砷的同时测定

目前矿石中砷的测定大多采用蒸馏—钼蓝法;苯萃取钼蓝法和铜试剂银—三氯甲烷萃取光度法等,但操作都比较繁琐。在锑(Ⅲ)存在下,锑磷钼蓝,锑砷钼蓝三元络合物测定钢铁中的磷和砷已有报导,本文着重介绍铁锰矿石中磷和砷的同时测定。采用硫代硫酸钠还原砷(Ⅴ)为砷(Ⅲ),以抗坏血酸—锑磷钼蓝测定磷;再以磷为参比液,测定磷砷合量中的砷。方法简单、快速准确。 一、试剂 混合熔剂:无水碳酸钠:草酸:硝酸钾     

电感耦合等离子体原子发射光谱法测定钨铁中砷、铜、锰、钼、磷、硅含量

建立了一种同时测定钨铁中砷、铜、锰、钼、磷、硅含量的电感耦合等离子体发射光谱法。以草酸-过氧化氢溶解试样,基体元素W、Fe和其他共存元素对待测元素的分析测定没有干扰。通过优化分析条件,得到砷、铜、锰、钼、磷、硅的检出限分别为0.009、0.006、0.000 1、0.000 3、0.005和0.002 μg/mL。该法加标回收率在95％～108%之间,相对标准偏差（n＝3）为0.1％～3.3％。方法用于标准样品的测定,所得结果与认定值相符。     

弹簧钢（65Si2MnWA）中高硅的快速测定

本文介绍了用硝酸溶样，硅钼蓝比色法测定弹簧钢中高硅的测定方法和影响因素的讨论。本方法操作简便，易于掌握，分析结果准确可靠，适用于弹簧铜及其它钢中0．1—4．5％的硅含量的测定。     

钼蓝分光光度法联合测定钢铁中磷砷

基于磷、砷具有相似的化学性质,在一定的酸度条件下,磷、砷都与钼酸铵和铋盐形成磷铋钼杂多酸、砷铋钼杂多酸,在抗坏血酸的作用下还原成磷铋钼蓝和砷铋钼蓝,且其吸光度值具有加合性,测定磷、砷合量的吸光度值后,用亚硫酸钠-硫代硫酸钠-溴化钾复合还原剂还原掩蔽砷,测定磷的吸光度值,从而可以分别测定磷、砷的含量。大多数的金属离子不干扰磷、砷的测定,只有硅在一定的酸度下产生干扰,可以用提高显色酸度的方法来消除,对于高含量硅可以通过分离除去。方法的线性范围为磷:0~0.75μg/mL;砷:0~1.25μg/mL。掩蔽还原砷后磷的显色稳定性较差,加入乳酸得到了改善。本方法用于实验室快速测定钢铁中的磷和砷。     

脱氧铜中磷的测定

本文建立了脱氧铜中磷的分析方法：在稀H2S04介质中,单独用SnCl^2还原磷钼黄为磷钼蓝,此法的最大吸收波长为680nm,磷含量在1．0-50μg／25ml范围内符合比尔定律。研究了十几种可能存在的共存离子对磷的影响,并将此法用于铜合金标样和脱氧铜中磷的测定,结果满意。     

磷钼蓝－罗丹明B－聚乙烯醇光度法测定氟化稀土中微量磷

磷钼蓝－罗丹明Ｂ－聚乙烯醇光度法测定氟化稀土中微量磷王金秀（湖南稀土金属材料研究所长沙,４ｌｍ１４）本文采用磷钼蓝－罗丹明Ｂ－聚乙烯醇三元配合物光度法,试样以铝盐与盐酸分解,酒石酸抑制硅的干扰等条件试验。测定下限０．３μｇ／５０ｍｌ,ε＿５８５＝１．...     

ICP-AES法测定铍铜合金中Be, Ni, Ti, Co, Fe, Al, Si, Mg和Pb

通过操作条件的试验研究，用基体匹配法校正基体干扰，并选择了最佳工作条件。样品加标回收率为96％～110％，方法快速、简便、可靠，适用于铍铜合金的快速检验。     

Regional mapping panels for chromosomes 3, 4, 5, 11, 15, 17, 18, and X

The erm family of 23S rRNA adenine-N6-methyltransferases confers resistance to all macrolide-lincosamide-streptograminB (MLS) antibiotics, but not all MLS antibiotics induce synthesis of Erm methyltransferase with equal efficiency in a given organism. The induction efficiency of a test panel of MLS antibiotics was studied by using two translational attenuator-lac reporter gene fusion constructs, one based on ermSV from Streptomyces viridochromogenes NRRL 2860 and the other based on ermC from Staphylococcus aureus RN2442. Four types of responses which were correlated with the macrolide ring size were seen, as follows: group 1, both ermSV and ermC were induced by the 14-membered-ring macrolides erythromycin, lankamycin, and matromycin, as well as by the lincosamide celesticetin; group 2, neither ermSV nor ermC was induced by the 12-membered-ring macrolide methymycin or by the lincosamide lincomycin or the streptogramin type B antibiotic ostreogrycin B; group 3, ermSV was selectively induced over ermC by the 16-membered-ring macrolides carbomycin, chalcomycin, cirramycin, kitasamycin, maridomycin, and tylosin; and group 4, ermC was selectively induced over ermSV by the 14-membered-ring macrolide megalomicin. These data suggest that the leader peptide determines the specificity of induction by different classes of MLS antibiotics and that for a given attenuator, a major factor which determines whether a given macrolide induces resistance is its size.     

铂饰品中Pt, Pd, Au, Ag, Cu, Ni, Zn, Fe的测定

试验研究建立了同一试料溶液连续、同时测定铂饰品中各成分的分析方法。主体Pt以氯铂酸铵称量法及火焰原子吸收光谱(FAAS)法或电感耦合等离子发射光谱(ICP-AES)法测定滤液中残留Pt进行补差而测定。主成分Pd,Au,Ag,Cu和焊料成分Ni,Zn,Fe以FAAS法或ICP-AES法测定。其方法回收率分别为:Pt99.9%~100%;Pd99.3%~99.7%;Au99.5%~l01.5%;Ag98.0%~100%;Cu97.7%~99.3%;Zn98.0%~99.0%;Ni94.0%~105%;Fe95.0%~99.0%。实际试样分析时,各成分质量分数之和一般在99.12%~l01.2%之间,接近于100%,间接说明方法的可靠性。本法适用于Pt-Pd二元体系和Pt-Pd-Au-Cu多元复杂体系的铂饰品的破坏分析,可用于校正X荧光光谱法无损检测铂饰品的分析结果。     

稀土金属中14种非稀土杂质的ICP-MS法同时测定

本文研究了用 ICP- MS仪器同时测定稀土金属中 Mg、Al、Ti、Cr、Mo、Mn、Co、Ni、Cu、Zn、Pb、W、Nb、Ta等 14种非稀土杂质。研究了各稀土基体对被分析元素的基体效应 ,选择了相匹配的内标元素。比较了标准曲线法与标准加入法的测定结果。确定了用内标元素校正基体效应及仪器漂移 ,以标准曲线法直接测定。进行了加料回收和精密度实验 ,回收率在 94%～ 113%之间 ,RSD<10 %。被分析元素的检出限为 0 .0 1～ 0 .2 0 ng/ m L,测定下限为1～ 2 0 μg/ g。     

Increased-contrast, high-spatial-resolution, diffusion-weighted, spin-echo, echo-planar imaging

An insertable head gradient coil with a maximum gradient amplitude of 45 mT/m and a rise time of 150 musec along all three major axes was used to collect high-spatial-resolution, single-shot, spin-echo, echo-planar, diffusion-weighted magnetic resonance images with b values ranging from 0 to 2,200 sec/mm2. Improvements in spatial resolution allowed better visualization of large white matter tracts and their relation to adjacent anatomic structures. Excellent contrast and anatomic detail were revealed for most structures in the brain when a sufficient number of acquisitions were collected.     

原子荧光光谱法测定土壤中的铅、铬、镉、汞、砷、锌、铜、镍等元素研究

土壤无机污染物铅、铬、镉、汞、砷、锌、铜、镍这八大重金属,是一般土壤检测中的必检项目。金属元素在土壤中积累富集后,有可能通过雨水迁移,造成地下水,地表水污染,或者通过农作物进入食物链,进而影响食品安全和人体健康,因此,对这些元素的检测显得尤为重要。本文采用原子荧光光谱法对土壤中的金属元素进行测量,同时结合微波消解技术对样品进行处理,确保测量数据的准确性。     

Susceptibilities of non-Pseudomonas aeruginosa gram-negative nonfermentative rods to ciprofloxacin, ofloxacin, levofloxacin, D-ofloxacin, sparfloxacin, ceftazidime, piperacillin, piperacillin-tazobactam, trimethoprim-sulfamethoxazole, and imipenem

Agar dilution MICs of 10 agents against 410 non-Pseudomonas aeruginosa gram-negative nonfermentative rods were determined. MICs at which 50 and 90% of the isolates were inhibited, respectively, were as follows (in micrograms per milliliter): sparfloxacin, 0.5 and 8.0; levofloxacin, 1.0 and 8.0; ciprofloxacin, 2.0 and 32.0; ofloxacin, 2.0 and 32.0; D-ofloxacin, 32.0 and > 64.0; ceftazidime, 8.0 and 64.0; piperacillin with or without tazobactam, 16.0 and > 64.0; trimethoprim-sulfamethoxazole, 0.5 and > 64.0; imipenem, 2.0 and > 64.0. With the exception of those for Stenotrophomonas maltophilia, Burkholderia cepacia, and Alcaligenes faecalis-A. odorans, agar dilution MICs for all strains tested were within 1 dilution of inhibitory (bacteriostatic) levels as determined by time-kill methodology.