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911.
电镀锌—镍合金的影响因素和反应机理 总被引:1,自引:1,他引:1
用原子发射光谱和扫描电镜等仪器研究了电镀锌-镍合金过程中诸多因素对镀层组成、性能的影响,探讨了施镀机理并了异常共沉积结论。 相似文献
912.
流动注射氢化物发生原子吸收光谱法测定发铅 总被引:4,自引:0,他引:4
发样消化液用铁氰化钾预先氧化处理将二价铅氧化为四价形态铅,以硼氢化钾为还原剂,稀盐酸为载液,用流动注射氢化物发生原子吸收光谱法测定铅。方法的检出限为0.26ng·ml-1,线性范围为0.60~35ng·ml-1,相对标准偏差为2.5%~4.7%,样品加标回收率为96.8%~104.4%,对人发标准物质进行测定,结果与标准值符合。方法灵敏度高、选择性好、试剂及样品用量少、操作方便快速,有推广应用价值。 相似文献
913.
Methylotrophic yeast Pichia pastoris is convenient for the expression of eukaryotic foreign proteins owing to its potential for posttranslational modifications,
protein folding, and facile culturing. In this work, human interleukin (hIL)-2 was successfully produced as a secreted fusion
form in recombinant P. pastoris. By employing green fluorescent protein (GFP) as a monitoring fusion partner, clear identification of fusion protein expression
and quantification of intracellular hIL-2 were possible even though there was no correlation between culture supernatant fluorescence
and secreted hIL-2 owing to high media interference. Importantly, by the addition of casamino acids in basal medium, we were
able to enhance threefold amount of secreted hIL-2, which was present both as a fusion and as a clipped fragment. 相似文献
914.
《Electroanalysis》2006,18(2):152-157
Capillary electrophoresis (CE) with contactless conductivity detection (CCD) represents a viable alternative to liquid chromatography in the analysis of amino acids (AA) in human plasma. After optimizing the composition of the background electrolyte (BGE), and introducing simple plasma pretreatment to remove spurious protein components, the CE/CCD methods allows determination of 18 from 20 proteinogenic AAs, three nonproteinogenic AAs and creatinine in 60 minutes. AAs are separated in their cationic forms in BGE containing 1.7 M acetic acid and 0.1% hydroxyethylcellulose, pH 2.2. LODs for individual AAs vary in an acceptable range with minimum of 4.3 μM for Arg and maximum of 42.9 μM for Cys. Mean concentrations and concentrations ranges for AAs in human plasma samples from 9 healthy individuals are found to agree well with those determined by an LC method in other two laboratories. 相似文献
915.
本文综述了在DNA测序方面分析化学的最新进展,包括电泳,毛细管电泳(CE),质谱(MS),电喷雾电离-质谱(ESI-MS),荧光光谱、共振离子谱(RIS)和单分子测定,同时还叙述了两维技术和多段测序方法的进展。 相似文献
916.
Phenol, catechol, and hydroquinone, are urinary end-products of the metabolism of benzene, nutrients, drugs, and endogenous substances. Recent research demonstrated that phenol, catechol, and hydroquinone, may have themselves a role in the carcinogenicity of benzene and in mechanisms that lead to leukemia. In this respect there is the need of rapid, low-cost, and possibly direct methods to quantitate these phenolic metabolites. Three single-residue coupled-column HPLC methods with fluorimetric detection (LC-LC-FLD) are described for the direct quantitation of phenol, catechol, and hydroquinone, in human urine. After enzymatic hydrolysis of the corresponding beta-glucuronoconjugates and sulfates, urine was directly injected into the LC-LC analyzer. The LC-LC-FLD procedure allowed base-to-base separation of the target compounds from urine interferents and good linearity (r2 = 0.998) within the ranges studied (0.5–50 mg L−1 for phenol, 0.35–35 mg L−1 for catechol and 0.2–10 mg L−1 for hydroquinone). Despite the high background levels of these metabolites in human urine, within- and inter-session precision expressed as RSD% was better than 20% on spiked and on authentic urine samples obtained from benzene-exposed workers. Accuracy expressed as the recovery ratio between measured and nominal concentration in spiked urine was comprised between 93% and 115% for the three metabolites. The column switching system was fully automated and computer-controlled, and was applied to the determination of phenol, catechol, and hydroquinone in urine samples showing a sample throughput of at least 20–30 samples per day.Revised: 21 February and 7 April 2005 相似文献
917.
用吸光光度法研究了水溶苯胺蓝(AnB)与牛血清白蛋白(BSA)在Britton-Robinson广泛pH缓冲介质中的结合反应,在最佳试验条件下,以试剂空白为参比,AnB-BSA复合物在600nm波长处的吸光度,与BSA的浓度呈良好的线性关系,BSA的线性范围为1.6×10-8~2.4×107mol.L-1,摩尔吸光系数ε=1.34×106L·mol-1·cm-1,Sandell灵敏度为0.051μg·cm-2,BSA的检出限为1.0×10-8mol·L-1,方法具有灵敏度较高、选择性好等特点,用于人血清样品中蛋白质的测定,与溴甲酚绿方法结果一致。 相似文献
918.
The complex interactions between human behaviors and social economic sciences is critically analyzed in this paper in view of possible applications of mathematical modeling as an attainable interdisciplinary approach to understand and simulate the aforementioned dynamics. The quest is developed along three steps: Firstly an overall analysis of social and economic sciences indicates the main requirements that a contribution of mathematical modeling should bring to these sciences; subsequently the focus moves to an overview of mathematical tools and to the selection of those which appear, according to the authors bias, appropriate to the modeling; finally, a survey of applications is presented looking ahead to research perspectives. 相似文献
919.
A sensible media simulation system for automobiles is introduced to open up new possibilities for an in‐car entertainment system. In this paper, the system architecture is presented, which includes a virtuality‐to‐reality adaptation scheme. Standard data schemes for context and control information from the International Standard MPEG‐V (ISO/IEC 23005) are introduced to explain the details of data formats, which are interchangeable in the system. A sensible media simulator and the implementation of a sensory device are presented to prove the effectiveness of the proposed system. Finally, a correlation between learning styles and sensory effects (that is, wind and vibration effects) is statistically analyzed using the proposed system. The experiment results show that the level of satisfaction with the sensory effects is unaffected overall by the learning styles of the test subjects. Stimulations by vibration effects, however, generate more satisfaction in people with a high tactile perception level or a low visual perception level. 相似文献
920.
Cory A. Hawkins Ilya A. Shkrob Carol J. Mertz Mark L. Dietz Michael D. Kaminski 《Analytica chimica acta》2012
A method has been developed for the isolation of strontium from human urine for subsequent determination in sample volumes as low as 5–20 mL. This method involves the acidification of the sample using methanesulfonic acid and its decolorization using charcoal, treatment of the filtrate with Diphonix® resin, and subsequent concentration of strontium on Sr resin. Data from retention model simulations provided the initial conditions which were then optimized by actual column separations. Diphonix® resin was shown to be effective at removing alkali metal ions from the urine matrix under conditions that retain higher valence ions. The suggested processing method provides 99% recovery of Sr2+, a concentration factor of 50, and an expected per sample processing time of less than 1 h. 相似文献