色谱峰纯度的定性方法

较系统地介绍了近年来国内外文献中有关色谱峰纯度的定性方法──仪器方法和化学计量学方法。仪器方法重点介绍了归一化比较光谱、吸收比法、光谱抑制法及导数技术。化学计量方法介绍了主成分分析法和渐近因子分析法。通过对文献方法和应用的简单介绍,比较了各种方法的特点及优缺点,总结了规律。     

非连续分子动力学模拟方法及其在大分子研究中的应用

计算机模拟技术已成为大分子构象等基础研究的一种重要手段。非连续分子动力学模拟(DMD)与传统的分子动力学模拟(MD)方法有所不同,基于不连续势能和相关的模拟编程方法,运行速度大大提高。本文讨论了DMD方法的特点,总结了DMD方法的应用,重点以蛋白质折叠为例介绍了如何使用DMD方法,最后对DMD方法的发展前景进行了展望。     

烟草制品及烟气中重金属检测方法的研究进展

从烟草制品及其烟气的前处理方法和检测方法两方面对烟草中重金属含量测定的研究进展进行了综述。重点介绍了湿法消解、微波消解、萃取和悬浮进样技术等样品前处理方法,以及原子光谱法、质谱法和液相色谱法等测定方法。列举了不同方法的灵敏度、准确性和适用范围,对各方法的优缺点进行了比较,并对烟草中重金属检测方法的发展进行了展望。     

重要性采样方法与自由能计算

分子动力学模拟与自由能计算已经在化学、生物学与材料学等领域得到广泛的应用。然而,由于在传统分子动力学模拟的时间尺度内,体系很难跨越较高的自由能能垒,在相空间内的采样大大受限,采样困难使自由能计算难以收敛。增强采样是解决这一问题的有效途径,重要性采样方法就是其中一类。本文综述了四种广泛应用的重要性采样方法--伞状采样方法、metadynamics方法、自适应偏置力方法和温度加速分子动力学方法的原理和进展,其中重点概述了自适应偏置力方法的最新发展--扩展自适应偏置力方法和扩展广义自适应偏置力方法,并对这四种重要性采样方法的优缺点进行了比较。最后,讨论和展望了重要性采样与自由能计算方法面临的挑战和前景,并提出了对自适应偏置力方法可能的改进,如与加速分子动力学（aMD）或弦方法结合以提高在高维度空间中的采样效率。     

利用电子表格自动处理数据高效检定常用玻璃量器

建立利用电子表格自动处理数据高效检定常用玻璃量器的方法。设计电子表格,利用表格处理数据,对常用玻璃量器检定数据自动检索、自动计算以及自动修约。该方法与传统衡量法相比,实现了数据自动计算处理,而且自动修约符合规定,消除了人为计算失误,提高了计算准确率,检定时间比传统方法缩减了约42%,统计学方法表明统计结果具有显著性差异（P<0.01）。该方法不仅成本低,而且提高了检定效率,降低了计算的差错率。     

微流控芯片设计方法研究进展

本文综述了微流控芯片设计方法的研究进展,归纳和总结了目前主要的设计方法,包括数值模拟法和基于宏模型的设计方法。最后介绍了宏-微模型设计方法,通过建立宏-微接口,实现了数值模拟和宏模型的灵巧桥接,有助于改善微流控芯片设计方法的兼容性和自适应性。     

自由基检测技术进展

重点对主要的几种自由基检测技术的发展情况进行了讨论,并评价了各种方法的优缺点。涉及的自由基检测技术主要有分光光度吸收法与荧光方法、高效液相色谱法、化学发光法、电化学方法、自旋捕集技术和毛细管电泳方法,按间接检测方法和直接检测方法分类进行了评价。     

高效液相色谱法测定水产品中喹乙醇的残留量

建立了水产品中喹乙醇残留量的测定方法。主要研究了样品的预处理方法,提出了以水为提取剂,以硼砂一硫酸锌为高效蛋白去除剂的样品处理方法。该方法灵敏、准确,适合于水产品中微量喹乙醇残留量的测定。方法的检出限为40μg／kg。     

基于凝固点下降的高纯有机物纯度定值技术研究进展

介绍凝固点测量方法的研究进展。阐述了凝固点下降技术用于高纯有机物纯度定值的基本原理和适用条件,详细介绍了静力学方法和动力学方法这两种凝固点的测量方法,并介绍了两种方法在纯度定值方面的应用情况,且对两种方法的特点进行了对比,展望了凝固点下降纯度定值技术的发展趋势。     

高效液相色谱-荧光法测定对虾组织中红霉素的残留量

建立了高效液相色谱-荧光法测定对虾组织中红霉素残留量的检测方法。主要研究了样品前处理方法。提出了以乙腈为提取剂,正己烷去脂、二氯甲烷反萃的新的样品处理方式。该方法简单,灵敏度高,方法检出限为150μg／kg,回收率≥75％。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

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%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

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.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

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.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.