共查询到20条相似文献,搜索用时 15 毫秒
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采用N2O-C2H2火焰原子吸收光谱法对变形钛合金中的铝进行分析.考察了铝的最佳测定条件、线性浓度范围以及样品分析中的干扰因素.实验表明,该方法测定结果的相对标准偏差小于0. 5%(n=6),加标回收率为97. 6%~99. 0%.该方法适用于变形钛合金中铝的分析,满足实验室化学分析技术与分析质量的控制要求. 相似文献
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采用火焰原子吸收分光光度法(AAS)和快速碘量法对工业污泥中铜含量进行测定,并对结果做了对比分析.结果表明两种方法的准确性和可操作性均较好,回收率在91.0%~99.0%之间,相对标准偏差均低于7%.碘量法分析简单,结果准确可靠,但不适合分析大批量的样品.火焰原子吸收分光光度法分析速度较快,灵敏度高,可以同时进行大批量的样品分析. 相似文献
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免疫分析是临床上检测生理相关蛋白质指标的主要方法. 与单一指标的免疫分析相比, 临床体外诊断对多指标的生理相关蛋白质免疫分析有着更为广泛的需求. 通过在固相载体上完成免疫反应的非均相免疫分析具有灵敏度高的优点, 是当前多指标免疫分析的主流方法. 本文按照固相载体的不同, 对近年来的多指标免疫分析系统分别从技术原理、 实现方法、 各自特点等方面的研究进展进行综合阐述. 最后对比总结了不同系统的优势与不足, 并展望了微流控多指标免疫分析在即时检测领域的发展前景. 相似文献
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酶解是蛋白质分析的重要前处理方法.微流控芯片具有样品耗样量小,可以实现样品的预处理、分离、富集、鉴定等分析过程于一体等特点.将酶固定在微流控分析芯片上,可以为蛋白质样品的分析提供一个高通量的技术平台. 相似文献
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刘佳蓉 《分析测试技术与仪器》2023,(1):93-100
变压器是变配电站的核心设备,其运行状况显著影响电网的安全与稳定.绝缘油是变压器中重要的工作介质,其在变压器运行中起到绝缘、散热等作用.矿物绝缘油是当前广泛使用的变压器绝缘油种类.绝缘油组分特性对变压器的工作性能影响很大.随着运行时间延长,绝缘油易出现氧化、老化,导致绝缘可靠性降低.准确分析绝缘油组分、早期发现绝缘油氧化、老化状况,对提高变压器运行安全水平有重要意义.质谱分析法在绝缘油组分特性分析、氧化产物及老化指示物分析中,展示了良好的应用潜力.综述了近年来质谱分析技术在绝缘油性能品质检测,氧化、老化产物检测及过程机理分析等方面的研究进展,提出了未来进一步提高绝缘油特性及故障分析准确度的建议. 相似文献
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用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%. 相似文献
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Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments. 相似文献
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The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines. 相似文献
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KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
The review contains a concise historical account and information on the most significant researches undertaken by the staff
at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry
of Heterocyclic Compounds.
Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008. 相似文献
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A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL. 相似文献
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Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products. 相似文献
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A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions. 相似文献