27 research outputs found

    Theoretical Investigations on Homogenous Organic Gold-Catalysis

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    近年来,金均相催化反应的研究进展迅速。从化学键的类型看,金催化剂能催化各种键C-X(X=C,Si,N,O,S,F,Cl,Br,I)的生成及断裂;从反应类型看,金催化剂可以催化烯炔环化、烯炔的亲核加成、C-H官能化、选择氧化、选择加氢等等反应。然而,在一些金均相催化反应中,催化活性物种不明,所涉及的高活性有机金中间体十分复杂,难以分离表征,还有反应本身具有环境敏感性,导致其反应机理难以理解,不利于利用和控制金催化反应。这些困难非现有实验技术能有效解决,从而给基于电子结构理论的量子化学手段提供了发挥的舞台,据此我们开展理论研究试图理解1)金催化物种的形成、结构及化学性质;2)一些复杂且难以分离表征...In recent years, great achievements have been scored in homogenous gold-catalysis, involving various kinds of substrates/products (e.g. C-X bond cleavage/formation, X=C, Si, N, O, S, F, Cl, Br, I) and types of reactions (e.g. cyclization, C-H functionlization, selective oxidation). However, to some gold-catalytical reactions, the active catalytic species are unknown, and the active organo-gold int...学位:理学博士院系专业:化学化工学院_物理化学(含化学物理)学号:2052008015017

    A Theoretical Study of the Mechanism for Allylic Ether Isomerization

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    采用MP2和密度泛函M06-2X方法,在6-31++g(d,P)基组水平上对烯丙基类不对称醚异构化反应机理进行了计算研究.揭示了其可能的反应途径,预测了互变异构吉布斯自由能,活化能等性质.计算结果表明,在没有金催化剂的条件下,尽管有醇溶剂时异构化活化能垒有所降低,异构化反应依然不容易进行.相反,存在金催化剂并且有醇溶剂情况下,烯丙基类不对称醚异构化反应活化自由能大大降低,仅为7.5 kCAl/MOl.通过比较有无醇溶剂和金催化剂对异构化的影响,揭示了金烯烃络合和醇分子参与反应以质子转移的异构化反应机理,很好解释了实验中观察的现象.计算结果还表明:醇分子不仅参与反应提供质子转移,它还能与醚竞争金催化剂络合,因此在高浓度醇条件下会抑制异构化反应进行.The reaction mechanism of allylic ether isomerization has been investigated by MP2 and DFT method(different functionals) with 6-31++G(d,p) basis set.The calculated results show that M06-2X method that designed to treat dispersion and hydrogen-bonded systems do better than traditional functional-B3LYP for the calculated energetic and structural properties of allylic ether isomerization.The optimal structures of allylic ether and transition states were located and the reaction Gibbs free energy barriers were predicted at the MP2 and M06-2X level.Furthermore, the possible reaction pathways and mechanisms were proposed to explain the origin of regioselectivity observed in experiment.The calculation results show that the isomerization reaction will not readily occur in the absence of catalysis by Au.The computed potential energy barrier is quite high, and things get better when alcohol molecules are introduced, resulting in the decrease of calculated activation free energy from 67.1 to 48.6 kcal/mol.However, the Au(I)-catalyzed addition of another molecule of alcohol to an allylic ether can occur readily.A protonated diether intermediate was stabilized by a hydrogen bond and the activation energies of allylic ether isomerization were dramatically decreased, only 7.5 kcal/mol.By contrast the isomerization effect under with and without alcohol, gold catalysis, the results indicate that the allylic ether isomerization involve cationic gold coordination and proton shift reaction process, which form the intermediate that allows the interconversion of the products.This reaction mechanism can successfully explain the observed regioselectivity for the thermodynamic product.Meanwhile, the results also show that the isomerization was completely inhibited with the excess alcohol due to competing gold coordination between alcohol and ether.The discovery of gold catalysts in allylic ether isomerization not only contributes to the development of catalysts from the usual transition metals to noble metals, but also shows the potential catalytic activities by switching the reaction conditions.国家自然科学基金(No.21273177); 西部之光计划资助~

    The Java Multi-threading Application about Mandelbrot Set

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    分析了java多线程环境下算法设计的特点,介绍了绘制Mandelbrot集的计算机算法,定义了Mandelbrot集的几个主要变量,并在此基础上给出了计算机算法的实现过程。应用java的多线程机制,良好的实现了对Mandelbrot集的图形绘制。The paper analyses the characteristic of algorithm design in Java multi-threading,introduce the algorithm about Mandelbrot det drawing on computer. Give the realization process and the Graphics

    不产子实体蛹虫草单孢子分离株的获得及RAPD分析

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    对优势蛹虫草原始菌株WWM04进行单孢子分离,共获得9个单孢子分离株,采用米饭培养基培养确证并且获得6个完全不产子实体的单孢子分离株。利用随机扩增多态性DNA(RAPD)分子标记方法对菌落差异的4个菌落特征典型的不产子实体单孢子分离株(SSP2、SSP7、SSP19和SSP21)、原始菌株以及由原始菌株12次转接后退化的菌株进行遗传多样性分析。结果表明,引物S37、S61对6个菌株的扩增谱带具有非常明显的特异性,该结果为蛹虫草退化分子标记奠定基础,并且在一定程度上也印证了蛹虫草异核现象和准性生殖理论

    HDST 技术应用于卵巢癌新辅助化疗中的效果分析

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    【目的】探讨卵巢癌患者新辅助化疗效果以及在卵巢癌常用化疗方案筛选中应用 HDST 技术的可行性。【方法】回顾性分析于中山大学孙逸仙纪念医院妇科肿瘤专科收治的 11 例按照 NCCN 指南推荐的行新辅助化疗的晚期卵巢癌患者,采集其社会人口学、临床资料及组织标本,并应用HDST 技术进行药敏检测。按照HDST 药敏结果进行分组,比较组间CA125、HE4 与Fagotti 评分指标总下降率的差异,探讨HDST 结果与患者肿瘤指标下降率的关系。【结果】HDST 结果显示6 例患者对选用的铂类药(顺铂或卡铂)不敏感,1 例患者对紫杉醇不敏感;经3次新辅助化疗后患者肿瘤指标均呈现明显的逐次下降趋势。HDST    结果与临床疗效间一致性较好(Kappa=1.000,P0.05)。【结论】HDST 技术在卵巢癌的新辅助化疗方案筛选上具有快速方便、经济实惠,结果与临床疗效一致的优势,有望为卵巢癌患者提供精准的个体化化疗方案

    Separation and Characterization of C70(C14H10) and C70(C5H6) from an

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    通讯作者地址: Xie, SY (通讯作者), Xiamen Univ, Coll Chem & Chem Engn, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, Coll Chem & Chem Engn, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Xiamen Univ, Coll Chem & Chem Engn, Dept Chem, Xiamen 361005, Peoples R China 3. Xiamen Univ, Fujian Prov Key Lab Theoret & Computat Chem, Xiamen 361005, Peoples R China 4. Xiamen Univ, Sch Life Sci, Xiamen 361005, Peoples R China 电子邮件地址: [email protected], [email protected] derivatives of fullerenes are prevalent in the fullerene-producing flame, the chemistry of these derivatives has rarely been discussed in the previous literature. In this paper, two D-Sh-C-70 derivatives, C-70(C14H10) and C-70(C5H6), were isolated from the soot of an acetylene benzene combustion. On the basis of detailed MS, NMR, IR, and UV/vis analyses in combination with DFT calculations, the cycloadduct structures of C-70(C14H10) and C-20(C5H6) were identified. Both the anthracene (C14H10) and the cyclopentadiene (C5H6) adducts, supposed as the intermediate species produced during the combustion process, were characterized to bond at a [6,6] ring junction at the end of the olivary C-70 cage. The present work exemplifies the capture of possible intermediates by the C-70 fullerene from the flame and thus provides insight into the mechanism responsible for the formation of fullerene-containing soot.NSFC21031004 20973137 21021061 973 projects 2007CB815301 2007CB81530

    Separation and Characterization of C70(C14H10) and C70(C5H6) from an Acetylene–Benzene–Oxygen Flame

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    [email protected], [email protected] derivatives of fullerenes are prevalent in the fullerene-producing flame, the chemistry of these derivatives has rarely been discussed in the previous literature. In this paper, two D(Sh)-C(70) derivatives, C(70)(C(14)H(10)) and C(70)(C(5)H(6)), were isolated from the soot of an acetylene benzene combustion. On the basis of detailed MS, NMR, IR, and UV/vis analyses in combination with DFT calculations, the cycloadduct structures of C(70)(C(14)H(10)) and C(20)(C(5)H(6)) were identified. Both the anthracene (C(14)H(10)) and the cyclopentadiene (C(5)H(6)) adducts, supposed as the intermediate species produced during the combustion process, were characterized to bond at a [6,6] ring junction at the end of the olivary C(70) cage. The present work exemplifies the capture of possible intermediates by the C(70) fullerene from the flame and thus provides insight into the mechanism responsible for the formation of fullerene-containing soot.NSFC 21031004 ,20973137,21021061 973 projects 2007CB815301 ,2007CB81530

    Simple Combustion Production and Characterization of Octahydro[60]fullerene with a Non-IPR C-60 Cage

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    1. Xiamen Univ, State Key Lab Phys Chem Solid Surface, Xiamen 361005, Peoples R China 2. Xiamen Univ, Dept Chem, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 3. Xiamen Univ, Sch Life Sci, Xiamen 361005, Peoples R ChinaFor the first time an easier, operable combustion method is employed for the synthesis of non-IPR fullerene, and an octahydro[60)fullerene with a non-IPA C-60 cage (C-60 isomer C-#1809(60)) produced by combustion is isolated and characterized by MS, UV vis, IR, and NMR spectroscopies in combination with DFT calculations. This finding shows that, in addition to chlorine, hydrogen can be an ample cataloreactant for the production of non-IPR fullerene derivatives under such conditions as arc-burning and diffusion combustion.NSFC 20525103 20673088 20973137 20721001 20423002 21031004 973 projects 2007CB815301 2007CB81530

    Combustion Synthesis and Electrochemical Properties of the Small Hydrofullerene C50H10

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    通讯作者地址: Xie, SY (通讯作者),Xiamen Univ, Coll Chem & Chem Engn, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, Coll Chem & Chem Engn, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Xiamen Univ, Coll Chem & Chem Engn, Dept Chem, Xiamen 361005, Peoples R China 3. Xiamen Univ, Sch Life Sci, Xiamen 361005, Peoples R China 电子邮件地址: [email protected]; [email protected] hydrofullerene C50H10 is synthesized by low-pressure benzeneoxygen diffusion combustion. The structure of C50H10 is identified through NMR, mass spectrometry, and IR and Raman spectroscopy as a D5h symmetric closed-cage molecule with five pairs of fused pentagons stabilized by ten hydrogen atoms. UV/Vis and fluorescence spectrometric analyses disclose its optical properties as comparable with those of its chloride cousin (C50Cl10). Cyclic and square-wave voltammograms reveal that the first reduction potential of C50H10 is more negative than that of C50Cl10 as well as C60, with implications for the utilization of C50H10 as a promising electron acceptor for photovoltaic applications.973 projects 2011CB935901 NSFC 21031004 21021061 2077310

    On lipid accumulation in oleaginuous microalgae affected by light intensity and its application in scale up cultivation

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    限制微藻生物质能源发展的最大瓶颈是规模化培养中低油脂产率所带来的高成本。强光能有效提高油脂产率,是既清洁又可持续的环境因素。因此,本文从高产油藻株的筛选,不同光强下藻株生长生理、生化组分变化,高光强下转录组、代谢组分析及规模化培养的应用等方面,围绕光强对微藻油脂积累展开了探究。主要结果如下: 从沙漠土壤结皮筛选到2株优良产油藻株Chlorella sp. L1和M. dybowskii Y2,室内的生理生化分析发现,高光强 (HL,400 mmol photons m-2s-1)虽然使它们的ROS含量上升,光合活性降低,叶绿体降解, 蛋白和碳水化合物含量下降,但脂质含量普遍升高,细胞体积整体变大,而且极性脂含量均下降,中性脂(NL)含量升高,产率分别达51.36 mg L-1d-1和 49.71 mg L-1d-1。室外波动光强下,高波动光强也显著利于油脂积累和NL的大幅提高,只是来源于膜脂重塑的TAG比例较低(11%-20%),大部分来自脂肪酸(FA)的从头合成或其它物质的转化。 转录组学(RNA-Seq)进一步分析发现,1) HL下M.dybowskii Y2的光合作用表达明显下调,但氧化磷酸化、ATP转运酶上调弥补了ATP生成的减少,TCA循环(sucB、CS、MDH)的上调表达提供了更多还原力。2) 参与C3固定、 糖酵解、戊糖磷酸和淀粉代谢的基因 第1d 显著上调,之后下降(如PFK、TPI、PGM、ENO、GAPDH、及淀粉和蔗糖合成酶等);而糖异生途径中的PCK和PPDK,及戊糖磷酸途径中RPE、G6PD、rpiA、PGM均明显上调,这为FA的生物合成提供了更多的中间 代谢物及能量。3) 氮代谢中谷氨酸脱氢酶转录水平剧烈上调,将谷氨酸氧化成α-酮戊二酸并释放,为TCA循环提供碳骨架;说明氮代谢通过增强TCA循环向碳代谢转化。4) FA合成相关的Accase、ACSL、FASN、FAB和TAG积累的PAP、DGAT和PDAT等基因均显著上调表达,这说明从头合成和膜脂转化是TAG大量积累的主要来源。首次在产油微藻中探究并揭示了强光影响油脂和TAG积累机制。鉴于盐诱导与光调控的互补性,本研究利用HL与盐(20 g L-1 NaCl)胁迫结合的两步诱导方法,使M. dybowskii XJ-15的油含量提高到50.37%,产率达76.72 mg L-1d-1,油脂品质均显著提高。代谢组学分析进一步发现,氨基酸、胺类、蛋白均被分解重新利用,碳水化合物在后期也被分解,海藻糖、多元醇等参与渗透平衡的调节;TCA循环中间代谢产物的明显下降,意味着它们是FA合成中乙酰CoA的主要来源;而C16:0和C18:1比例的显著升高、及C18:2和C18:3比例的显著下降,证明膜脂的重塑和FA从头合成促进了TAG的大量积累。在光强调控的规模化应用中,温度常伴随作用;本研究首先探究了温度对M. dybowskii Y2油脂积累的影响。发现15 oC和35 oC条件均能促进油脂积累,35 oC下油脂产率最高;油脂组成方面,15 oC促进极性脂积累,而35 oC促进NL积累。然后将HL与15oC、25oC和35 oC联合诱导油脂积累;结果显示各组均能促进NL积累,中性脂产率都超过40 mg L-1 d-1 ,且HL与 35 oC下的产率最高。 最后,将多株候选产油微藻在强光下进行了规模化培养,发现柱状反应器(140 L)中,Chlorella sp. L1和M.dyboswkii Y2批量培养的油脂产率分别为9.06 和8.05 g m-2d-1 ;平板生物反应器下,可多次半连续培养,且使油脂产率分别达16.22和13.17 g m-2d-1(15 L),24.31 和16.36 g m-2d-1 (96 L);开放池(200 m2 ORP)中,半连续培养也较批量培养更高(前者为5.15 vs 4.06 g m-2d-1;后者为 5.35 vs 3.00 g m-2d-1);高光强与盐诱导下(5 m2 ORP),使M. dybowskii XJ-151的油脂产率(3.74 g m-2d-1)提高了27.21%。然后,基于两年200 m2 ORP的培养数据,对Chlorella sp. L1和M. dybowskii Y2的生产工艺做了生命周期评价和经济成本分析
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