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1.
Ab initio method under the effective core potential (ECP) approximation is employed to study the reaction mechanism of carbonyl migration of the cycle of olefin hydroformylation catalyzed by a carbonyl cobalt HCo(CO)3 at Hartree-Fock (HF) level. The structures of the reactant, transition state and product for the reaction are determined. The energy of each stationary point is corrected at MP2/LAN2DZ//LANL2DZ+ZPE (zero-point energy) level. The calculated activation barrier is 28.89 kJ/mol.  相似文献   

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He-HCl和Ne-HCl分子间势的从头计算研究   总被引:1,自引:0,他引:1  
本文在CCSD(T)理论水平下,采用aug-cc-pVQZ基函数对He-HCl和Ne-HCl的分子间势进行了系统的研究。结果表明:He-HCl和Ne-HCl均以线形结构存在。复合物He-HCl和He-Cl-H及其Ne-H-Cl和Ne-Cl-H的相互作用能几乎相等。文章的最后还对基函数及理论方法对分子间势的影响进行了详细的分析。  相似文献   

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采用从头算方法研究了异氰酸与甲醛环加成反应的机理,并研究了BH3对此反应的催化效应。结果表明,非催化反应基本上为同步的协同反应,而BH3催化的反应则为非同步的协同反应,且BH3催化反应比非催化反应容易进行得多。  相似文献   

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The molecular model of Trifluoromethylthiosulphenyl Chloride, CF3SSCl, was presented.Ab initio method was used to calculate the structure and Raman and Infrared spectra. The results show that CF3SSCl possess stereoscopic structure ofC 1 symmetry with a torsional angle of 94.2°. The potential energy distribution and isotope replacement methods were applied to determine the vibrational assignment. The vibrational frequencies and corresponding modes of the molecule were obtained. The calculated vibrational frequencies are in good agreement with experiments. Supported by the National Natural Science Foundation of China Zou Xianwu: born in Apr, 1938, Professor  相似文献   

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TheP-T paths of the Xiaoqinling metamorphic core complex (XMCC) have been investigated with the Gibbs method by researching the compositional changing of zoned epidotes which formed during syn-deformation metamorphism. TheseP-T paths indicate that the XMCC had experienced the following thermodynamics processes: firstly, near isobaric falling slightly in temperature in lower crust; secondly, fast decompression and rising in temperature during extensional uplifting to middle crust level; and finally, isobaric falling in temperature in middle crust. The upwelling and emplacement of the deep magma may be a major factor during the uplifting processes of the metamorphic core complex.  相似文献   

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Using Mn(OH)2 as precursor, LiOH as lithiating agent and (NH4)2S2O8 as oxidant, layeredo-LiMnO2 was obtained by a novel method—in situ oxidation-intercalation under mild conditions (80 °C). The product was characterized by XRD, ICP, TEM and7Li-NMR. The results reveal that orthorhombic LiMnO2 with high purity and good crystallinity can be obtained by this method. During electrochemical tests, a LiMnO2/Li cell shows an initial reversible capacity of 208 mAh · g−1 and a reversible capacity of 180 mAh · g−1 after 30 cycles at room temperature.  相似文献   

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A coupled chemiluminescence method for the determination of some carboxylic acids was developed, based on their enhancement the chemiluminescence light emission of the reaction of tirs (2,2′-bipyridine) ruthenium(II) and Ce(IV) in sulfuric acid medium. The conditions for their determination were optimized. The following detection limits were obtained: oxalic acid, 2.67×10−8 mol/L; propandioic acid, 1.20×10−6 mol/L; pyruvic acid, 1.35×10−8 mol/L; citric acid, 5.10×10−8 mol/L; barbituric acid, 2.48×10−7 mol/L. The proposed method was successfully applied to determination of oxalic acid. The coupled chemiluminescent reaction mechanism and rate equation are proposed. Foundation item: Supported by the National Natural Science Foundation of China and the Natural Science Foundation of Hubei Province Biography: HAN He-you (1962-), male, Associate professor, phD, graduate candidate  相似文献   

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氧硫化碳(OCS)是大气中含量丰富的含硫气体,也是唯一一种能通过扩散进入平流层的含硫物种. 采用高水平分子轨道理论方法研究了OCS与CN自由基在2A′势能面上的反应机理. 在B3LYP/6-31G(2df)水平下优化了反应物、中间体、过渡态及产物的构型参数,并进行了振动频率分析. 单点能计算采用QCISD(T)/-311+G(3df)理论水平. 在QCISD(T)/6-311+G(3df)//B3LYP/6-31G(2df)水平下构筑了反应的势能剖面. 计算结果表明:在通常的大气条件下,NCS和CO是主要反应产物. 然而,随着温度的升高,生成CNS和CO的反应通道可能变成竞争反应通道.  相似文献   

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Reflection mechanism for reuse software architecture (RMRSA) divides a software architecture into base-level architecture and meta-level architecture logically. Base-level architecture is the ordinary architecture; meta-level represents and manipulates the reusable meta-information of base-level architecture explicitly. Through reflection, the modification of meta-level architecture will result in the modification of the architecture in base-level. Then we can gain a new base-level architecture design. In this paper, we use π-calculus to define the constituents and their interaction processes of RMRSA, by these definition, we specify the business function in base-level at runtime, and illustrate the reflection mechanism between the base-level architecture and meta-level architecture.  相似文献   

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 考虑了碱金属原子高激发态价电子与原子实电子coulomb相互作用、交换相互作用以及极化相互作用(长程关联效应),计算了碱金属原子Li,Na,K高激发态(6≤N≤15,l≤2)波函数及能级.计算结果表明:交换势取为GKS势时,能级计算值比实验值偏低;取为hammerling势时,计算值与实验值符合很好.  相似文献   

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利用生物柴油副产物甘油和CO2干重整制取高附加值合成气,关键是高性能催化剂的选择和研究。通过胶体溶液燃烧法制备了CoFe/CeO2催化剂,在固定床反应器中,温度范围650~800 ℃条件下,研究了CO2与甘油干重整过程中的催化活性和稳定性。结果表明,胶体溶液燃烧法制备的CoFe/CeO2催化剂具有典型的介孔结构,比表面积为33.4~40.8 m2/g,表现出了活性组分Co-Fe与载体CeO2较强的相互作用。 7CoFeCe显示出了较好的干重整催化性能,750 ℃下甘油转化率达84.8%,CO2转化率达19.9%。随着温度的升高,CO2转化率提高,在800 ℃下,CO2转化率达到了30.3%,表明高温有利于逆水汽变换反应。稳定性实验表明,介孔CoFe/CeO2催化剂具有较好的干重整稳定性。  相似文献   

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The interactively interfacial reactions between the iron-reducing bacterium (Shewanella decolorationis, S12) and iron oxide (α-FeOOH) were investigated to determine reductive dechlorination transformation of chlorinated organic compounds (chloroform and pentachlorophenol). The results showed that the interactive system of S12+ α-FeOOH exhibited relatively high dechlorination rate. By comparison, the S12 biotic system alone had no obvious dechlorination, and the α-FeOOH abiotic system showed low dechlorination rate. The enhanced dechlorination of chloroform and pentachlorophenol in the interactive system of S12+α-FeOOH was derived from the promoted generation of adsorbed Fe(Ⅱ) by S12. A decrease in redox potential of the Fe (Ⅲ)/Fe (Ⅱ) couple in the interactive reaction system was determined by cyclic voltammetry. Our results will give new insight into interactively interfacial reaction between iron-reducing bacterium and iron oxides for degradation of chlorinated organic compounds under anaerobic condition.  相似文献   

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In situ time-resolved FTIR spectroscopy was used to study the reaction mechanism of partial oxidation of methane (POM) to synthesis gas and the reaction of CH4/O2/He (2/1/45, molar ratio) gas mixture with adsorbed CO species over Rh/SiO2, Ru/γ-Al2O3 and Ru/SiO2 catalysts at 500—600℃. It was found that CO is the primary product of POM reaction over reduced and working state Rh/SiO2 catalysts. Direct oxidation of CH4 is the main pathway of synthesis gas formation over Rh/SiO2 catalyst. CO2 is the primary product of POM over Ru/γ-Al2O3 and Ru/SiO2 catalysts. The dominant reaction pathway for synthesis gas formation over Ru/γ-Al2O3 catalyst is via the reforming reactions of CH4 with CO2 and H2O. For the POM reaction over Rh/SiO2 and Ru/γ-Al2O3 catalysts, consecutive oxidation of surface CO species is an important pathway of CO2 formation.  相似文献   

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运用求积分的方法研究了含有一维p-Laplacian算子的二阶三点边值问题:{(|u′(t)|p-2 u′(t))′+λf(u(t))=0,t∈(0,1),u(0)=0,u(1)=u(η)多重正解的存在性,其中p∈(1,2],0η1是常数,λ∈(0,+∞)是一个参数,对于常数r0时,f∈C1([0,r),[0,+∞)),在(0,r)上f(s)0,且lim s→r-(r-s)p-1 f(s)=+∞。  相似文献   

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为探究南方红豆杉(Taxus wallichiana var.mairei)中10-去乙酰基巴卡亭Ⅲ(10-DAB)的最佳提取工艺,本研究以南方红豆杉中10-DAB含量为指标,以料液比、提取时间及超声温度为考察因素,采用单因素试验结合响应面法优化10-DAB的提取工艺,并采用超高效液相色谱(UPLC)法检测不同采摘部位、不同生长年限及不同采收时节的10-DAB含量差异。结果表明,南方红豆杉中10-DAB的最佳提取工艺条件为料液比1∶15(g/mL)、提取时间23 min、超声温度40℃,该工艺条件下10-DAB的含量为1.18%,与理论值相对偏差为0.42%。UPLC检测结果表明,南方红豆杉叶的10-DAB含量显著高于枝和树皮,且10-DAB全年累积含量受季节影响明显,10月份达到最高值。该研究可为南方红豆杉中10-DAB的提取利用提供参考依据。  相似文献   

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提出了一种改进的乘子交替方向法(ADMM)算法,基于松弛技术和预测-校正框架,将松弛算子引入子问题x和对偶变量λ,使得每次迭代的步长大于1,从而提高了算法的收敛性,并在变分不等式的框架下证明了该算法的收敛性。此外,数值实验中通过图像去模糊问题验证了算法的有效性,并基于多组对照实验,综合考虑收敛效率和图像质量,选取适当的收敛准则。  相似文献   

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