期刊文献+
共找到628篇文章
< 1 2 32 >
每页显示 20 50 100
基于DFT的氢基竖炉内H_(2)和CO在Fe_(2)O_(3)(0001)表面反应的机理
1
作者 唐珏 储满生 +1 位作者 刘西财 刘杰 《东北大学学报(自然科学版)》 北大核心 2025年第7期139-147,共9页
氢基竖炉工艺可显著减少CO_(2)排放,是钢铁工业绿色低碳发展的有效途径.本研究基于密度泛函理论(DFT),深入研究了氢基竖炉冶炼过程中H_(2)和CO与Fe_(2)O_(3)的反应机理.结果表明:H_(2)分子最稳定吸附构型的吸附能为-1.65 eV,CO分子为-2.... 氢基竖炉工艺可显著减少CO_(2)排放,是钢铁工业绿色低碳发展的有效途径.本研究基于密度泛函理论(DFT),深入研究了氢基竖炉冶炼过程中H_(2)和CO与Fe_(2)O_(3)的反应机理.结果表明:H_(2)分子最稳定吸附构型的吸附能为-1.65 eV,CO分子为-2.10 eV,CO分子吸附占优.H_(2)分子反应时的能垒为0.64 eV,CO分子为1.40 eV,H_(2)分子与Fe_(2)O_(3)反应在动力学上占优.升高温度虽然不利于气体分子的吸附,但有利于还原反应的进行,因此升高温度可以弥补H_(2)分子吸附及反应在热力学上的劣势.对于富氢或纯氢竖炉,可以提高操作压力,同时适当提高还原温度以加快反应速率,但应确保吸附效率. 展开更多
关键词 氢基竖炉 密度泛函理论(dft) Fe_(2)O_(3) 反应机理 吸附能 能垒
在线阅读 下载PDF
甲醇在Cu_(4)-C_(5)N_(2)H_(2)表面吸附和裂解机理的DFT研究 被引量:2
2
作者 王婉楠 任瑞鹏 吕永康 《分子催化(中英文)》 北大核心 2025年第1期34-40,I0002,共8页
开发高效稳定的甲醇制甲醛催化剂意义重大,但催化剂稳定性差和甲醛选择性低的问题仍然存在.以嵌入氮化碳中的铜四原子团簇(Cu_(4)-C_(5)N_(2)H_(2))催化剂作为模型,基于DFT-D3探索了甲醇在催化剂表面吸附和裂解反应机理.结果表明,Cu_(4)... 开发高效稳定的甲醇制甲醛催化剂意义重大,但催化剂稳定性差和甲醛选择性低的问题仍然存在.以嵌入氮化碳中的铜四原子团簇(Cu_(4)-C_(5)N_(2)H_(2))催化剂作为模型,基于DFT-D3探索了甲醇在催化剂表面吸附和裂解反应机理.结果表明,Cu_(4)-C_(5)N_(2)H_(2)具有优异的稳定性和高的甲醛选择性,甲醇在Cu_(4)-C_(5)N_(2)H_(2)表面裂解的最优路径为CH_(3)OH→CH_(3)O→CH_(2)O,电荷分析结果显示催化剂与甲醇之间的电子转移使得甲醇得以活化.这些结果为合理设计高效甲醇制甲醛催化剂提供了理论指导. 展开更多
关键词 甲醇 甲醛 dft Cu_(4)-C_(5)N_(2)H_(2) 裂解机理
在线阅读 下载PDF
FeMo双原子催化CO_(2)氧化C_(3)H_(8)反应机理的DFT研究
3
作者 高鑫海 王婉楠 +2 位作者 石涛 任瑞鹏 吕永康 《分子催化(中英文)》 北大核心 2025年第3期208-215,I0001,I0002,共10页
CO_(2)氧化C_(3)H_(8)脱氢反应可有效抑制过度脱氢现象并提高丙烯产率,但如何设计高效催化剂是关键.本研究构建了Fe/Mo-C_(2)N和Fe/MoS-C_(2)N两种催化剂模型,并基于密度泛函理论探索了C_(3)H_(8)和CO_(2)在催化剂表面的反应机理.研究... CO_(2)氧化C_(3)H_(8)脱氢反应可有效抑制过度脱氢现象并提高丙烯产率,但如何设计高效催化剂是关键.本研究构建了Fe/Mo-C_(2)N和Fe/MoS-C_(2)N两种催化剂模型,并基于密度泛函理论探索了C_(3)H_(8)和CO_(2)在催化剂表面的反应机理.研究结果表明,所构建的催化剂可以实现FeMo双原子同步活化C_(3)H_(8)和CO_(2),C_(3)H_(8)+CO_(2)→CH_(3)CHCH_(3)+COOH→CH_(3)CHCH_(2)+CO+H_(2)O为最优路径.差分电荷分析结果显示,S掺杂促进了Mo原子向CO_(2)的电荷转移,从而提升催化活性.本研究可为设计CO_(2)氧化C_(3)H_(8)脱氢反应催化剂提供理论依据. 展开更多
关键词 双原子催化 FeMo dft C_(3)H_(8) CO_(2) C_(2)N
在线阅读 下载PDF
Multi-attribute group decision making method under 2-dimension uncertain linguistic variables 被引量:4
4
作者 JIANG Kexin ZHANG Quan YAN Manting 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2020年第6期1254-1261,共8页
A method is proposed to deal with the uncertain multiple attribute group decision making problems,where 2-dimension uncertain linguistic variables(2DULVs)are used as the reliable way for the experts to express their f... A method is proposed to deal with the uncertain multiple attribute group decision making problems,where 2-dimension uncertain linguistic variables(2DULVs)are used as the reliable way for the experts to express their fuzzy subjective evaluation information.Firstly,in order to measure the 2DULVs more accurately,a new method is proposed to compare two 2DULVs,called a score function,while a new function is defined to measure the distance between two 2DULVs.Secondly,two optimization models are established to determine the weight of experts and attributes based on the new distance formula and a weighted average operator is used to determine the comprehensive evaluation value of each alternative.Then,a score function is used to determine the ranking of the alternatives.Finally,the effectiveness of the proposed method is proved by an illustrated example. 展开更多
关键词 2-dimension uncertain linguistic variables(2DULVs) multi-attribute group decision making problem score function distance formula
在线阅读 下载PDF
Boosting nitrogen electrocatalytic fixation by three-dimensional TiO_(2-δ)N_δnanowire arrays 被引量:4
5
作者 Jianjia Mu Xuan-Wen Gao +4 位作者 Zhaomeng Liu Wen-Bin Luo Zhenhua Sun Qinfen Gu Feng Li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第12期293-300,I0008,共9页
Owing to the environmental and inherent advantages,nitrogen reduction reaction(NRR)by electrocatalysts attracts global attention.The surface engineering is widely employed to enhance the electrocatalytic activity by a... Owing to the environmental and inherent advantages,nitrogen reduction reaction(NRR)by electrocatalysts attracts global attention.The surface engineering is widely employed to enhance the electrocatalytic activity by atomic defects and heterostructure effects.A three-dimensional(3D)free-standing integrated electrode was fabricated by numerous nearly-single-crystal TiO_(2-δ)N_δnanowire arrays.Based on the high electronic conductivity network,it exposes numerous active sites as well to facilitate the selective nitrogen adsorption and*H adsorption suppression.The synergistic effects between Ti^(3+)and oxygen vacancy(O_v)boost the intrinsic catalytic activity,in which Ti^(3+)acquired electrons via Ovcan effectively activate the N≡N bond and make it easy to bind with protons.The energy barrier of primary protonation process(*N_(2)+H^(+)+e^(-)→*NNH)can be dramatically decreased.The highest ammonia yield rate(14.33μg h^(-1)mgcat^(-1))emerges at-0.2 V,while the optimal ammonia Faradaic efficiency(9.17%)is acquired at-0.1 V.Density functional theory(DFT)calculation reveals that the Ti^(3+)can be served as the active sites for nitrogen adsorption and activation,while ammonia synthesis is accomplished by the distal pathway.The high electronic conductivity integrated network and synergistic effects can significantly facilitate nitrogen absorption and accelerate electrocatalytic reaction kinetic,which are responsible for the excellent NRR performance at room temperature. 展开更多
关键词 Nanowires TiO_(2-δ)N_δ Electrocatalysis NRR dft
在线阅读 下载PDF
Multisoliton Solutions of the (2+1)-Dimensional KdV Equation 被引量:1
6
作者 ZHANG Jie-Fang HUANG Wen-Hua 《Communications in Theoretical Physics》 SCIE CAS CSCD 2001年第11期523-524,共2页
Using the extension homogeneous balance method,we have obtained some new special types of soliton solutions of the (2+1)-dimensional KdV equation.Starting from the homogeneous balance method,one can obtain a nonlinear... Using the extension homogeneous balance method,we have obtained some new special types of soliton solutions of the (2+1)-dimensional KdV equation.Starting from the homogeneous balance method,one can obtain a nonlinear transformation to simple (2+1)-dimensional KdV equation into a linear partial differential equation and two bilinear partial differential equations.Usually,one can obtain only a kind of soliton-like solutions.In this letter,we find further some special types of the multisoliton solutions from the linear and bilinear partial differential equations. 展开更多
关键词 multisoliton (2+1)-dimensions KdV EQUATION
在线阅读 下载PDF
On Boolean elements and derivations in 2-dimension linguistic lattice implication algebras
7
作者 ZHU Hua ZHAO Jian-bin 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2023年第2期274-292,共19页
A 2-dimension linguistic lattice implication algebra(2DL-LIA)can build a bridge between logical algebra and 2-dimension fuzzy linguistic information.In this paper,the notion of a Boolean element is proposed in a 2DL-L... A 2-dimension linguistic lattice implication algebra(2DL-LIA)can build a bridge between logical algebra and 2-dimension fuzzy linguistic information.In this paper,the notion of a Boolean element is proposed in a 2DL-LIA and some properties of Boolean elements are discussed.Then derivations on 2DL-LIAs are introduced and the related properties of derivations are investigated.Moreover,it proves that the derivations on 2DL-LIAs can be constructed by Boolean elements. 展开更多
关键词 DERIVATION Boolean element Lattice implication algebra(LIA) 2-dimension linguistic lattice implication algebra(2DL-LIA) 2-dimension fuzzy linguistic information
在线阅读 下载PDF
2-Dimension Interleaver Design for IDMA Systems 被引量:1
8
作者 Jian-Hao Hu Cheng-Hai Zhang Ling Xiang 《Journal of Electronic Science and Technology of China》 2009年第2期97-103,共7页
A new design method interleavers,2-dimension interleavers,are proposed for interleave division multiple access(IDMA)systems.With a same interleaving rule named I',the row indices and column indices of a traditiona... A new design method interleavers,2-dimension interleavers,are proposed for interleave division multiple access(IDMA)systems.With a same interleaving rule named I',the row indices and column indices of a traditional block interleaving matrix are scrambled to obtain an interleaver,which is marked as the master interleaver.F is produced by a loworder PN sequence generator.Two ways are provided for generating different interleavers.One is that all interleavers are generated by the circular shifting master interleaver.The other is that different inter leavers are generated by different Ts.Besides,we prove that the minimum distance between two adjacent bits resulted from 2-dimension interleaves is much larger than that of other schemes,such as random interleavers,power interleavers,and shiffting interleaves.The simulation results show that 2-dimension interleavers can achieve much better performance with much less resource consumption than random interleavers in IDMA systems. 展开更多
关键词 Index Terms-2-dimension interleavers interleave-division multiple access minimum distance randominterleavers shifting interleavers.
在线阅读 下载PDF
LOCALIZED COHERENT STRUCTURES OF THE (2+1)-DIMENSIONAL HIGHER ORDER BROER-KAUP EQUATIONS
9
作者 ZHANG Jie-fang(张解放) +1 位作者 LIU Yu-lu(刘宇陆) 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2002年第5期549-556,共8页
By using the extended homogeneous balance method, the localized coherent structures are studied. A nonlinear transformation was first established, and then the linearization form was obtained based on the extended hom... By using the extended homogeneous balance method, the localized coherent structures are studied. A nonlinear transformation was first established, and then the linearization form was obtained based on the extended homogeneous balance method for the higher order (2 + 1)-dimensional Broer-Kaup equations. Starting from this linearization form equation, a variable separation solution with the entrance of some arbitrary functions and some arbitrary parameters was constructed. The quite rich localized coherent structures were revealed. This method, which can be generalized to other (2 + I) -dimensional nonlinear evolution equation, is simple and powerful. 展开更多
关键词 higher order Broer-Kaup equation (2+1)-dimension coherent structure homogeneous balance method
在线阅读 下载PDF
Two-dimensional C_(2)N-based single-atom catalyst with complex microenvironment for enhanced electrochemical nitrogen reduction:A descriptor-based design
10
作者 Enduo Dai Wei An +4 位作者 Ruixian Guo Xugen Shi Yunyi Li Yibo Wang Mingming Liu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第10期110-119,I0003,共11页
The catalytic descriptor with operational feasibility is highly desired towards rational design of high-performance catalyst especially the electrode/electrolyte solution interface working under mild conditions.Herein... The catalytic descriptor with operational feasibility is highly desired towards rational design of high-performance catalyst especially the electrode/electrolyte solution interface working under mild conditions.Herein,we demonstrate that the descriptorΩparameterized by readily accessible intrinsic properties of metal center and coordination is highly operational and efficient in rational design of single-atom catalyst(SAC)for driving electrochemical nitrogen reduction(NRR).Using twodimensional metal(M)-B_(x)P_(y)S_(z)N_m@C_(2)N as prototype SAC models,we reveal that^(*)N_(2)+(H~++e~-)→^(*)N_(2)H acts predominantly as the potential-limiting step(PLS)of NRR on M-B_(2)P_(2)S_(2)@C_(2)N and M-B_(1)P_(1)S_(1)N_(3)@C_(2)N regardless of the distinction in coordination microenvironment.Among the 28 screened M active sites,withΩvalues close to the optimal 4,M-B_(2)P_(2)S_(2)@C_(2)N(M=V(Ω=3.53),Mo(Ω=5.12),and W(Ω=3.92))and M-B_(1)P_(1)S_(1)N_(3)@C_(2)N(M=V(Ω=3.00),Mo(Ω=4.34),and W(Ω=3.32))yield the lowered limiting potential(U_(L))as-0.45,-0.54.-0.36,-0.58,-0.25,and-0.24 V,respectively,thus making them the promising NRR catalysts.More importantly,these SACs are located around the top of volcano-shape plot of U_(L) versusΩ,re-validatingΩas an effective descriptor for accurately predicting the high-activity NRR SACs even with complex coordination.Our study unravels the relationship between active-site structure and NRR performance via the descriptorΩ,which can be applied to other important sustainable electrocatalytic reactions involving activation of small molecules viaσ-donation andπ^(*)-backdonation mechanism. 展开更多
关键词 ELECTROCATALYSIS N_(2) reduction Single-atom catalyst DESCRIPTOR dft
在线阅读 下载PDF
Bifurcation of travelling wave solutions for(2+1)-dimension nonlinear dispersive long wave equation
11
作者 RONG Ji-hong TANG Sheng-qiang 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2009年第3期291-297,共7页
In this paper,the bifurcation of solitary,kink,anti-kink,and periodic waves for(2+1)-dimension nonlinear dispersive long wave equation is studied by using the bifurcation theory of planar dynamical systems.Bifurcation... In this paper,the bifurcation of solitary,kink,anti-kink,and periodic waves for(2+1)-dimension nonlinear dispersive long wave equation is studied by using the bifurcation theory of planar dynamical systems.Bifurcation parameter sets are shown,and under various parameter conditions,all exact explicit formulas of solitary travelling wave solutions and kink travelling wave solutions and periodic travelling wave solutions are listed. 展开更多
关键词 solitary wave kink and anti-kink wave periodic wave (2+1)-dimension nonlinear dispersive long wave equation
在线阅读 下载PDF
New Exact Solutions for the Generalized (2 + 1)-dimensional Nonlinear Schroedinger Equation with Variable Coefficients
12
作者 JIANG Zhi-ping 《Chinese Quarterly Journal of Mathematics》 CSCD 2012年第2期224-231,共8页
With the help of the variable-coefficient generalized projected Ricatti equation expansion method, we present exact solutions for the generalized (2+1)-dimensional nonlinear SchrSdinger equation with variable coeff... With the help of the variable-coefficient generalized projected Ricatti equation expansion method, we present exact solutions for the generalized (2+1)-dimensional nonlinear SchrSdinger equation with variable coefficients. These solutions include solitary wave solutions, soliton-like solutions and trigonometric function solutions. Among these solutions, some are found for the first time. 展开更多
关键词 2+1)-dimensions nonlinear SchrSdinger equation variable coefficients projected Ricatti equation expansion method
在线阅读 下载PDF
Brief investigations on Cu_(x)Ta_(2-x)O_(5) for thermoelectric and optical responses using density functional and experimental techniques
13
作者 Laiba Ashraf Salma Waseem +4 位作者 Maria Khalil Naveed Ahmad Pervaiz Ahmad Imen Kebaili Murtaza Saleem 《Chinese Physics B》 2026年第2期620-629,共10页
Cu_(x)Ta_(2-x)O_(5) compositions were investigated for advanced thermoelectric and optical applications,using both simulations and experimental approaches.Density functional theory calculations were performed before t... Cu_(x)Ta_(2-x)O_(5) compositions were investigated for advanced thermoelectric and optical applications,using both simulations and experimental approaches.Density functional theory calculations were performed before the experimental observations to predict the trends of various parameters.Crystal structure analysis confirmed the presence of the orthorhombic Ta_(2)O_(5) phase in all the compositions.The composition and morphology demonstrated impurity-free contents with uniform and crack-free surfaces.Thermoelectric analysis depicted a decrease in Seebeck coefficient from 3.66??V·K^(-1)to 1.91??V·K^(-1)and an increase in the value of specific heat from 0.73 J·K^(-1)·kg^(-1)to 11.6 J·K^(-1)·kg^(-1)upon Cu incorporation in structure.The bandgap was found to reduce from 2.61 to 1.38 e V with Cu-induced electronic states.The real epsilon and static refractive index increased from 3.75 to 4.57 and from 1.93 to 2.11,respectively,with increment in Cu content.The enhanced parameters,focusing on the thermoelectric and optical responses,make these compositions potential candidates for advanced optoelectronic applications. 展开更多
关键词 Ta_(2)O_(5) dft electronic properties thermoelectric properties optical properties
原文传递
A magnetically recyclable CoFe_(2)O_(4)/BiOBr S-scheme heterojunction for efficient photocatalytic degradation of diuron:Performance,durability and mechanism exploration
14
作者 Guie Li Chunyan Yang +4 位作者 Qiu Yang Qingzhu Zheng Menghan Li Jianhua Qu Guangshan Zhang 《Chinese Chemical Letters》 2026年第1期584-597,共14页
The excessive use of pesticides has exacerbated environmental pollution due to herbicide residues,while their persistent toxicity poses serious challenges to global ecological security.A magnetically recyclable CoFe_(... The excessive use of pesticides has exacerbated environmental pollution due to herbicide residues,while their persistent toxicity poses serious challenges to global ecological security.A magnetically recyclable CoFe_(2)O_(4)/BiOBr S-scheme heterojunctions was prepared by microwave-assisted co-precipitation method for photocatalytic degradation of Diuron(DUR) in water.The formation of S-scheme heterojunction enhances electron transfer and charge separation,which was demonstrated by free radical trapping,electrochemical experiments,and DFT calculations.The magnetic CoFe_(2)O_(4)/BiOBr catalysts can achieve 99.9 %removal of diuron in 50 min under visible light irradiation.Furthermore,the system maintains stable performance across a broad p H range(3-9),enabling adaptation to diverse water environments,effective elimination of multiple pollutants,and strong resistance to ionic interference.Using magnetic recovery,CoFe_(2)O_(4)/BiOBr exhibits a high removal rate of 99 % and a markedly low ion leaching rate(<20 μg/L) after six cycles photocatalytic process,confirming its excellent stability and durability.According to HPLCQTOF-MS and DFT calculation,the main ways of DUR degradation include dechlorinated hydroxylation,dealkylation and hydroxylation of aromatic ring and side chain.Toxicity analysis showed that the toxicity of the intermediates generated during degradation was generally lower than that of DUR.The magnetic CoFe_(2)O_(4)/BiOBr S-scheme heterojunction developed in this study exhibits excellent photocatalytic performance,high applicability,good stability,and durability,providing an effective magnetic for the removal of refractory pollutants. 展开更多
关键词 CoFe_(2)O_(4)/BiOBr DIURON DURABILITY dft calculations Photocatalytic degradation
原文传递
不饱和类硅烯H_2C=SiNaF的DFT研究 被引量:6
15
作者 李文佐 宫宝安 程建波 《物理化学学报》 SCIE CAS CSCD 北大核心 2006年第6期653-656,共4页
用密度泛函理论方法,在B3LYP/6-31+G(d,p)水平上研究了不饱和类硅烯H2C=SiNaF的结构.结果表明,不饱和类硅烯H2C=SiNaF共有四种平衡构型,其中非平面的p-配合物型构型能量最低,是不饱和类硅烯H2C=SiNaF存在的主要构型.对平衡构型间异构化... 用密度泛函理论方法,在B3LYP/6-31+G(d,p)水平上研究了不饱和类硅烯H2C=SiNaF的结构.结果表明,不饱和类硅烯H2C=SiNaF共有四种平衡构型,其中非平面的p-配合物型构型能量最低,是不饱和类硅烯H2C=SiNaF存在的主要构型.对平衡构型间异构化反应的过渡态进行了计算,求得了转化势垒.计算预言了最稳定构型的振动频率和红外强度. 展开更多
关键词 不饱和类硅烯H2C=SiNaF dft 异构化
在线阅读 下载PDF
AlCl_3催化歧化制备二甲基二氯硅烷的DFT和MP2研究(II) 被引量:6
16
作者 徐文媛 何忠义 +2 位作者 陈玉 李凤仪 洪三国 《化学学报》 SCIE CAS CSCD 北大核心 2005年第16期1474-1478,共5页
研究一甲基三氯硅烷与三甲基氯硅烷分别与三氯化铝作用并得到中间体后,中间体分别与一甲基三氯硅烷和三甲基氯硅烷作用的机理,反应的IRC(Intrinsicreactioncoordinate)曲线,各关键原子沿IRC的变化曲线及产物的理论产率.结果发现,中间体... 研究一甲基三氯硅烷与三甲基氯硅烷分别与三氯化铝作用并得到中间体后,中间体分别与一甲基三氯硅烷和三甲基氯硅烷作用的机理,反应的IRC(Intrinsicreactioncoordinate)曲线,各关键原子沿IRC的变化曲线及产物的理论产率.结果发现,中间体趋于与一甲基三氯硅烷作用生成二甲基二氯硅烷,且三甲基氯硅烷的转化率高于一甲基三氯硅烷.实验结果与计算结果吻合. 展开更多
关键词 二甲基二氯硅烷 歧化 DFF MP2 ALCL3 催化歧化 甲基三氯硅烷 dft 三甲基氯硅烷 制备
在线阅读 下载PDF
一种利用短时DFT分析实现全数字2DPSK接收机解调的新算法 被引量:8
17
作者 欧阳喜 葛临东 《电讯技术》 北大核心 2001年第1期59-62,共4页
本文提出了一种简单而实用的利用短时DFT(ST -DFT)分析实现全数字 2DPSK接收机的解调算法。该算法对由多谱勒效应引起的时变频率漂移具有鲁棒性。由于该算法是通过检测在载频处的瞬时能量谱的跳变来实现 2DPSK信号的解调 ,所以该算法不... 本文提出了一种简单而实用的利用短时DFT(ST -DFT)分析实现全数字 2DPSK接收机的解调算法。该算法对由多谱勒效应引起的时变频率漂移具有鲁棒性。由于该算法是通过检测在载频处的瞬时能量谱的跳变来实现 2DPSK信号的解调 ,所以该算法不需要进行专门的载波相位恢复、符号定时 ,且具有较好的抗噪性能 ,实现起来简单。 展开更多
关键词 全数字接收机 2DPSK 短时dft 解调算法
在线阅读 下载PDF
水溶液环境下手性配合物Phe·Ca^(2+)对映异构机理的DFT研究 被引量:11
18
作者 赵丽红 彭国强 +3 位作者 郝成欣 苏丹 姜春旭 王佐成 《中山大学学报(自然科学版)(中英文)》 CAS CSCD 北大核心 2023年第6期50-60,共11页
采用DFT(density functional theory)的M06-2X、MN15方法和处理溶剂效应的SMD模型方法,研究了水溶液中S-苯丙氨酸(S-Phe)与二价钙(Ca^(2+))配合物(Phe·Ca^(2+))的对映异构。反应通道研究发现,S-Phe·Ca^(2+)的对映异构可在质子... 采用DFT(density functional theory)的M06-2X、MN15方法和处理溶剂效应的SMD模型方法,研究了水溶液中S-苯丙氨酸(S-Phe)与二价钙(Ca^(2+))配合物(Phe·Ca^(2+))的对映异构。反应通道研究发现,S-Phe·Ca^(2+)的对映异构可在质子以N和O分别为桥以及O和N联合为桥迁移的3个通道上实现。计算表明:最优势通道是质子以N为桥迁移,隐性水溶剂效应下决速步自由能垒是227.5 kJ/mol,显性水溶剂效应下该能垒降至108.0~117.6 kJ/mol。结果表明:水溶液中手性Phe·Ca^(2+)的消旋过程十分缓慢,将其用于生命体同补苯丙氨酸和钙元素可能比较安全。 展开更多
关键词 苯丙氨酸 二价钙 dft(density functional theory) 对映异构 自由能垒
在线阅读 下载PDF
[Ru(bpy)2(phen)]^2+主配体上双取代效应DFT法研究 被引量:3
19
作者 郑康成 王菊平 +2 位作者 沈勇 匡代彬 云逢存 《化学学报》 SCIE CAS CSCD 北大核心 2001年第8期1283-1289,共7页
对钌联吡啶菲咯啉配合物[Ru(bpy)2(phen)]2+及其主配体(phen)上5,6-双取代衍生物,用密度泛函(DFT)法在B3LYP/LanL2DZ水平上进行理论计算研究.探讨供电子基团(OH)和拉电子基团(F)在主配体上的取代对配合物的电子结构及相关性质,如配合物... 对钌联吡啶菲咯啉配合物[Ru(bpy)2(phen)]2+及其主配体(phen)上5,6-双取代衍生物,用密度泛函(DFT)法在B3LYP/LanL2DZ水平上进行理论计算研究.探讨供电子基团(OH)和拉电子基团(F)在主配体上的取代对配合物的电子结构及相关性质,如配合物前沿分子轨道的能量、组成、光谱性质、原子的净电荷布居及配位键长键角等的影响规律.计算结果表明,取代基对该系列取代衍生物的电子结构,特别是第一激发态的电子云分布影响较大,拉电子基团(F)能活化主配体,钝化辅助配体;而供电子基团(OH)则相反.无论是供电子基团(OH),还是拉电子基团(F)都导致取代衍生物的电子基谱带红移.此外,用基于极性交替规律及极性叠加概念的多系列箭头的图示方法对主配体上的原子净电荷布居的特征作了讨论.计算结果能较好地解释有关的实验现象与规律. 展开更多
关键词 2 2′-联吡啶 钌(Ⅱ)联吡啶配合物 1 10-菲咯啉 密度泛函数 双取代效应
在线阅读 下载PDF
反式共轭类碳烯CH_2CH—CHC∶LiF氢迁移反应的DFT研究 被引量:5
20
作者 李文佐 宫宝安 程建波 《分子科学学报》 CAS CSCD 2007年第1期28-32,共5页
应用密度泛函理论DFT方法,在B3LYP/6-31G*水平上研究了反式共轭类碳烯CH2CH—CHC∶LiF的氢迁移反应.计算优化了反应过程中的所有反应物、中间体、过渡态和产物的几何构型,通过频率振动分析确定中间体和过渡态.结果表明,在β位上的H... 应用密度泛函理论DFT方法,在B3LYP/6-31G*水平上研究了反式共轭类碳烯CH2CH—CHC∶LiF的氢迁移反应.计算优化了反应过程中的所有反应物、中间体、过渡态和产物的几何构型,通过频率振动分析确定中间体和过渡态.结果表明,在β位上的H原子迁移过程中,经历一个带有三元环结构的中间体和两个带有三元环结构的过渡态.第一步反应势垒较大. 展开更多
关键词 反式共轭类碳烯CH2=CH-CH=C:LiF dft B3LYP 氢迁移反应
在线阅读 下载PDF
上一页 1 2 32 下一页 到第
使用帮助 返回顶部