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Revealing the correlation between adsorption energy and activation energy to predict the catalytic activity of metal oxides for HMX using DFT
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作者 Xiurong Yang Chi Zhang +6 位作者 Wujing Jin Zhaoqi Guo Hongxu Gao Shiyao Niu Fengqi Zhao Bo Liu Haixia Ma 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期262-270,共9页
Traditional selection of combustion catalysis is time-consuming and labor-intensive.Theoretical calculation is expected to resolve this problem.The adsorption energy of HMX and O atoms on 13 metal oxides was calculate... Traditional selection of combustion catalysis is time-consuming and labor-intensive.Theoretical calculation is expected to resolve this problem.The adsorption energy of HMX and O atoms on 13 metal oxides was calculated using DMol3,since HMX and O are key substances in decomposition process.And the relationship between the adsorption energy of HMX,O on metal oxides(TiO_(2),Al_(2)O_(3),PbO,CuO,Fe_(2)O_(3),Co_(3)O_(4),Bi_(2)O_(3),NiO)and experimental T30 values(time required for the decomposition depth of HMX to reach 30%)was depicted as volcano plot.Thus,the T30 values of other metal oxides was predicted based on their adsorption energy on volcano plot and validated by previous experimental data.Further,the adsorption energy of HMX on ZrO_(2)and MnO_(2)was predicted based on the linear relationship between surface energy and adsorption energy,and T30 values were estimated based on volcano plot.The apparent activation energy data of HMX/MgO,HMX/SnO_(2),HMX/ZrO_(2),and HMX/MnO_(2)obtained from DSC experiments are basically consistent with our predicted T30 values,indicating that it is feasible to predict the catalytic activity based on the adsorption calculation,and it is expected that these simple structural properties can predict adsorption energy to reduce the large quantities of computation and experiment cost. 展开更多
关键词 Density functional theory HMX Metal oxides Adsorption energy activation energy
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Integrating the valence theory and the norm activation theory to understand consumers’ e-waste recycling intention
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作者 Hong Thi Thu Nguyen 《Chinese Journal of Population,Resources and Environment》 2023年第1期26-36,共11页
Electrical and electronic waste(e-waste)is a growing challenge,matching the widespread boom in the use of information and communication technology.Opposite to an alarming increasing amount of e-waste,a low rate of con... Electrical and electronic waste(e-waste)is a growing challenge,matching the widespread boom in the use of information and communication technology.Opposite to an alarming increasing amount of e-waste,a low rate of consumer engagement in ensuring the proper disposal of such materials intensifies the pressure on the exist‐ing e-waste crisis.To deal with this thorny problem,it is of great interest to grasp consumers’disposal and re‐cycling behavioral intentions.Therefore,this study attempts to understand complementary perspectives around consumers’e-waste recycling intention based on the integration of the valence theory and the norm activation theory.Four data mining models using classification and prediction-based algorithms,namely Chi squared automatic interaction detector(CHAID),Neural network,Discriminant analysis,and Quick,unbiased,efficient statistical tree(QUEST),were employed to analyze a set of the 398 data collected in Vietnam.The re‐sults revealed that the social support value is by far the most critical predictor,followed by the utilitarian value,task difficulty,and monetary risk.It is also noteworthy that the awareness of consequences,education background,the ascription of responsibility,and age were also ranked as critical affecting factors.The lowest influential predictors found in this study were income and gender.In addition,a comparison was made in terms of the classification performance of the four utilized data mining techniques.Based on several evalua‐tion measurements(confusion matrix,accuracy,precision,recall,specificity,F-measure,ROC curve,and AUC),the aggregated results suggested that CHAID and Neural network performed the best.The findings of this research are expected to assist policymakers and future researchers in updating all information surround‐ing consumer behavioral intention-related topics focusing on e-waste.Furthermore,the adoption of data min‐ing algorithms for prediction is another insight of this study,which may shed the light on data mining applica‐tions in such environmental studies in the future. 展开更多
关键词 CHAID Discriminant analysis E-waste recycling intention Neural network Norm activation theory QUEST Sustainable development goals Valence theory
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The Role of Trait Activation Theory in Occupational Behavior:A Systematic Review
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作者 Paraskevi Tasoula Michael Galanakis 《Psychology Research》 2023年第2期83-87,共5页
The Trait Activation Theory(TAT)is widely regarded as the most influential personality theory approach in psychology.The purpose of this study is to analyze the TAT’s role in the contemporary workplace.Which personal... The Trait Activation Theory(TAT)is widely regarded as the most influential personality theory approach in psychology.The purpose of this study is to analyze the TAT’s role in the contemporary workplace.Which personality traits are more likely to predict work success?Which characteristics should businesses prioritize throughout the recruiting and selection processes?According to the Trait Activation Theory,what is the significance of motivation in the workplace and how can employers find employees who can be more productive,efficient,and involved in the organization’s goals?A systematic review of past recent research was used to answer the questions raised above.Following the gathering and examination of multiple recent publications on the issue,it was determined that the use of this model had a favorable impact on individual and group performance,working relationships,manager job performance,and workplace creativity. 展开更多
关键词 Trait activation theory Big Five theory WORKPLACE personality traits work behavior job performance leadership group innovation core self-evaluation autonomy
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The New Foundation of Organizational Psychology.Trait Activation Theory in the Workplace:Literature Review 被引量:1
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作者 Maria Manteli Michael Galanakis 《Psychology Research》 2022年第12期939-945,共7页
Trait Activation Theory(TAT)is a comprehensive examination of the personality-job fit and is based on the model of job performance.This theory’s main argument is how individuals express their personal traits when exp... Trait Activation Theory(TAT)is a comprehensive examination of the personality-job fit and is based on the model of job performance.This theory’s main argument is how individuals express their personal traits when exposed to trait-relevant situational cues.The trait-relevant situation can be assessed through the cues that play a role in the manifestation of trait-relevant behaviors.The situational cues may originate from social,task,and organization.These cues may provoke or trigger the behaviors related to traits but not related to performance measures.The three central principles suggested in TAT are:(1)personal traits are expressed in the behaviors related to work as responses to the situation cues that are trait-relevant,(2)trait-relevant situation cues originate from social,task,and organization,(3)job performance and work behaviors that are trait expressive are distinct,with job performance to be discussed as valued work behavior.The research conducted and presented below includes articles that are in the majority of the last two decades and the findings suggest that TAT was reviewed usually against managerial roles and qualities.In some articles,TAT was also reviewed and researched together with other major personality theories to explain behavior. 展开更多
关键词 Trait activation theory(TAT) personality traits situational cues job-fit performance
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Preliminary Explanation on "Natural Activation Theory" Based on "Fenlong"
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作者 Benhui Wei 《Agricultural Biotechnology》 CAS 2019年第3期112-115,共4页
Based on action mechanism of "Fenlong technology" with the maximum activation potential of global natural resources,"natural resources activation theory"("activation theory") is proposed ... Based on action mechanism of "Fenlong technology" with the maximum activation potential of global natural resources,"natural resources activation theory"("activation theory") is proposed firstly.Its connotation contains two parts.One is directly activating some natural resources in land,such as unutilized plough bottom of existing cultivated land and soil resources below it,saline-alkali land,degraded grassland,ecological reconstruction of desertification land,inter-row of fruit trees,lawn of sponge city,etc.The other is indirectly activating some natural resources in ground space,such as natural precipitation,solar energy,oxygen,terrestrial eco-environment,soil resources,river waters and even climate change factors.It could release and generate huge physical endogenous force and cyclic force,and increase food source and available water resources,which is favorable for human survival,nature's own ecological balance,harmonious coexistence and balance between man and nature,without harming nature itself.Moreover,its supporting theoretical system is explained from five aspects.It is pointed that the "activation theory" is deep derivation of "Fenlong technology" and "Fenlong science".By sufficiently playing the potential of natural resources,it could reach human-dominated comprehensive balance and coordinated development of air,sunshine,water,soil,nutrient,microorganism,plant,livestock and poultry,marine organism in the nature.The "activation theory" is concrete embodiment of respecting,changing and using the nature,and new channel of realizing sublimation of "life community of human and nature" and benefiting mankind. 展开更多
关键词 Fenlong technology NATURAL RESOURCES activation theory Life COMMUNITY
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Theoretical Study on the C-H Activation in Decarbonylation of Acetaldehyde by NiL_2(L=SO_3CH_3) Using Density Functional Theory
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作者 刘红飞 JIA Tiekun MIN Xinmin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第6期1170-1172,共3页
Density functional theory calculations were carried out to explore the potential energy surface(PES) associated with the gas-phase reaction of Ni L2(L=SO3CH3) with acetone. The geometries and energies of the react... Density functional theory calculations were carried out to explore the potential energy surface(PES) associated with the gas-phase reaction of Ni L2(L=SO3CH3) with acetone. The geometries and energies of the reactants, intermediates, products and transition states of the triplet ground potential energy surfaces of [Ni, O, C2, H4] were obtained at the B3LYP/6-311++G(d,p) levels in C,H,O atoms and B3LYP/ Lanl2 dz in Ni atom. It was found through our calculations that the decabonylation of acetaldehyde contains four steps including encounter complexation, C-C activation, aldehyde H-shift and nonreactive dissociation. The results revealed that C-C activation induced by Ni L2(L=SO3CH3) led to the decarbonylation of acetaldehyde. 展开更多
关键词 density functional theory decarbonylation transition state energy C-C activation
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The Activation and Application of Schema Theory in Pre-listening Activity
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作者 程晓燕 马媛 《科技视界》 2016年第2期136-136,共1页
In this paper,the author will base on the important function of schema applied in teaching English listening,analyze the definition and classification of schema theory.Then,explain how important it is in pre-listening... In this paper,the author will base on the important function of schema applied in teaching English listening,analyze the definition and classification of schema theory.Then,explain how important it is in pre-listening activities to activate students’schema. 展开更多
关键词 英语 听力教学 教学方法 教育学
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Computation of Diffusion Activation Energies of C, N in γFe 被引量:2
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作者 苏文勇 张瑞林 邵彬 《Journal of Beijing Institute of Technology》 EI CAS 2002年第1期105-108,共4页
A structure relaxation model based on the empirical electron theory of solids and molecules is developed to compute the diffusion active energies of C, N in γFe. First, adding a restriction, the lattice maintains rig... A structure relaxation model based on the empirical electron theory of solids and molecules is developed to compute the diffusion active energies of C, N in γFe. First, adding a restriction, the lattice maintains rigidity when solute atom migrates to the saddle point. In this step, the hybridization classes of every atom do not change. Then, the restriction is loosed and the atoms are relaxed under the coulomb repulsive forces. It is supposed that the energy needed in the first step would be compensated partly by the second step. In this way, the diffusion active energies of C, N in γFe are computed. Compared with the experiment data, the relative errors are less than 5%, which are good results in the computation of activation energy of diffusion. 展开更多
关键词 diffusion active energy empirical electron theory electronic structure
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The Application of Goal-Setting Theory in the Second Classroom Teaching Activities of College English
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作者 宋琳琳 胡春华 《英语广场(学术研究)》 2012年第5期93-95,共3页
Interest is the precondition and motivation for people's accomplishment.However,due to the exam-oriented system,millions of parents and teachers neglect the interests of children,and our children nearly forget the... Interest is the precondition and motivation for people's accomplishment.However,due to the exam-oriented system,millions of parents and teachers neglect the interests of children,and our children nearly forget their interests or hobbies.Based on different interests of children,the thesis analyzes how to apply the goal-setting theory in the second classroom teaching activities of College English,using the example of Lushan College of Guangxi University of Technology. 展开更多
关键词 goal-setting theory second class teaching activities College English
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Project-based Language Learning: an Activity Theory Analysis in SOE Language Learning
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作者 陈苡晴 《海外英语》 2016年第10期215-217,220,共4页
This study focuses on the effectiveness of the project-based language learning(PBLL) in a college Secretarial Oral English(SOE) Module. Student reflections of the language project work have been analyzed through Activ... This study focuses on the effectiveness of the project-based language learning(PBLL) in a college Secretarial Oral English(SOE) Module. Student reflections of the language project work have been analyzed through Activity Theory. Moreover,Data has been collected and categorized based on the components of complex human activity: the subject, object, tools(signs,symbols, and language), the community in which the activity take place, division of labor, and rules. The findings theoretically support the outcome of project-based language learning which align with the object of the activity. 展开更多
关键词 activITY theory PROJECT-BASED LEARNING SOE LANGUAGE LEARNING
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Effect of vacancy defects on electronic properties and activation of sphalerite(110) surface by first-principles 被引量:11
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作者 陈建华 陈晔 李玉琼 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第3期502-506,共5页
The electronic properties of sphalerite(110) surface with Zn-vacancy and S-vacancy were calculated by using density-functional theory,and the effects of vacancy defect on the copper activation of sphalerite were inves... The electronic properties of sphalerite(110) surface with Zn-vacancy and S-vacancy were calculated by using density-functional theory,and the effects of vacancy defect on the copper activation of sphalerite were investigated.The calculated results indicate that surface state occurs in the band gap of Zn-vacancy sphalerite,which is from the contribution of S 3p orbital at the first layer of the surface.The presence of S-vacancy results in surface state appearing near the Fermi level and the bottom of conductor band,which are composed of S 3p and Zn 4s orbital,respectively.The surface structure of Zn-vacancy sphalerite is more stable than S-vacancy surface due to the occupation of Zn-vacancy by Cu atoms;hence,the substitution reaction of Cu for Zn vacancy is easier than the substitution of Cu for Zn atoms with S-vacancy surface. 展开更多
关键词 SPHALERITE vacancy defect Density Functional theory calculations copper activation
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Physical activity during pregnancy and the role of theory in promoting positive behavior change:A systematic review 被引量:1
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作者 Erika L.Thompson Cheryl A.Vamos Ellen M.Daley 《Journal of Sport and Health Science》 SCIE 2017年第2期198-206,共9页
Background: Physical activity(PA) during pregnancy provides physical and psychological benefits for mother and child. U.S. guidelines recommend ≥30 min of moderate exercise for healthy pregnant women most days of the... Background: Physical activity(PA) during pregnancy provides physical and psychological benefits for mother and child. U.S. guidelines recommend ≥30 min of moderate exercise for healthy pregnant women most days of the week; however, most women do not meet these recommendations. Theory assists in identifying salient determinants of health behavior to guide health promotion interventions; however, the application of theory to examine PA among pregnant women has not been examined cohesively among multiple levels of influence(e.g.,intrapersonal, interpersonal, neighborhood/environmental, and organizational/political). Subsequently, this systematic review aims to identify and evaluate the use of health behavior theory in studies that examine PA during pregnancy.Methods: Articles published before July 2014 were obtained from Pub Med and Web of Science. Inclusion criteria applied were:(1) empiricallybased;(2) peer-reviewed;(3) measured factors related to PA;(4) comprised a pregnant sample; and(5) applied theory. Fourteen studies were included. Each study's application of theory and theoretical constructs were evaluated.Results: Various theories were utilized to explain and predict PA during pregnancy; yet, the majority of these studies only focused on intrapersonal level determinants. Five theoretical frameworks were applied across the studies—all but one at the intrapersonal level. Few determinants identified were from the interpersonal, neighborhood/environmental, or organizational/political levels.Conclusion: This systematic review synthesized the literature on theoretical constructs related to PA during pregnancy. Interpersonal, community,and societal levels remain understudied. Future research should employ theory-driven multi-level determinants of PA to reflect the interacting factors influencing PA during this critical period in the life course. 展开更多
关键词 Physical activity PREGNANCY theory
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Comparative study of different theories on active earth pressure 被引量:1
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作者 S.P.Yap F.A.Salman S.M.Shirazi 《Journal of Central South University》 SCIE EI CAS 2012年第10期2933-2939,共7页
Determination of distribution and magnitude of active earth pressure is crucial in retaining wall designs. A number of analytical theories on active earth pressure were presented. Yet, there are limited studies on com... Determination of distribution and magnitude of active earth pressure is crucial in retaining wall designs. A number of analytical theories on active earth pressure were presented. Yet, there are limited studies on comparison between the theories. In this work, comparison between the theories with finite element analysis is done using the PLAXIS software. The comparative results show that in terms of distribution and magnitude of active earth pressure, RANKINE's theory possesses the highest match to the PLAXIS analysis. Parametric studies were also done to study the responses of active earth pressure distribution to varying parameters Increasing soil friction angle and wall friction causes decrease in active earth pressure. In contrast, active earth pressure increases with increasing soil unit weight and height of wall. RANK/NE's theory has the highest compatibility to finite element analysis among all theories, and utilization of this theory leads to proficient retaining wall design. 展开更多
关键词 active earth pressure retaining wall PLAXIS comparative study RANKINE's theory COULOMB's theory
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Mode-Coupling Theory for Glass Transition of Active-Passive Binary Mixture 被引量:1
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作者 Meng-kai Feng Zhong-huai Hou 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2018年第4期584-594,616,共12页
Collective behaviours of active particle systems have gained great research attentions in re- cent years. Here we present a mode-coupling theory (MCT) framework to study the glass transition of a mixture system of a... Collective behaviours of active particle systems have gained great research attentions in re- cent years. Here we present a mode-coupling theory (MCT) framework to study the glass transition of a mixture system of active and passive Brownian particles. The starting point is an eff)ctive Smoluchowski equation, which governs the dynamics of the probability dis- tribution function in the position phase space. With the assumption of the existence of a nonequilibrium steady state, we are able to obtain dynamic equations for the intermediate scattering functions (ISFs), wherein an irreducible memory function is introduced which in turn can be written as functions of the ISFs based on standard mode-coupling approximations. The effect of particle activity is included through an effective difIusion coefficient which can be obtained via short time simulations. By calculating the long-time limit of the ISF, the Debye-Waller (DW) factor, one can determine the critical packing fraction ηc of glass transition. We find that for active-passive (AP) mixtures with the same particle sizes, ηc increases as the partial fraction of active particle xA increases, which is in agreement with previous simulation works. For system with different active/passive particle sizes, we find an interesting reentrance behaviour of glass transition, i.e., ηc shows a non-monotonic dependence on xa. In addition, such a reentrance behaviour would disappear if the particle activity is large enough. Our results thus provide a useful theoretical scheme to study glass transition behaviour of active-passive mixture systems in a promising way. 展开更多
关键词 Glass transition Mode-coupling theory active particles active-passive par ticle mixture
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A Mechanistic Switch in C-H Bond Activation by Elusive Fe^(V)(O)(TAML)Reaction Intermediate:A Theoretical Study 被引量:1
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作者 Anran Zhou Zhiqiang Fu +2 位作者 Xuanyu Cao Yufen Zhao Yong Wang 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2022年第2期383-389,I0032-I0064,I0004,共41页
The divergent behavior of C-H bond oxidations of aliphatic substrates compared to those of aromatic substrates shown in Gupta’s experiment was mechanistically studied herein by means of density functional theory calc... The divergent behavior of C-H bond oxidations of aliphatic substrates compared to those of aromatic substrates shown in Gupta’s experiment was mechanistically studied herein by means of density functional theory calculations.Our calculations reveal that such difference is caused by different reaction mechanisms between two kinds of substrates(the aliphatic cyclohexane,2,3-dimethylbutane and the aromatic toluene,ethylbenzene and cumene).For the aliphatic substrates,C-H oxidation by the oxidant Fe^(V)(O)(TAML)is a hydrogen atom transfer process;whereas for the aromatic substrates,C-H oxidation is a proton-coupled electron transfer(PCET)process with a proton transfer character on the transition state,that is,a proton-coupled electron transfer process holding a proton transfer-like transition state(PCET(PT)).This difference is caused by the strongπ-πinteractions between the tetra-anionic TAML ring and the phenyl ring of the aromatic substrates,which has a“pull”effect to make the electron transfer from substrates to the Fe=O moiety inefficient. 展开更多
关键词 C-H bond activation Hydrogen atom transfer Proton coupled electron transfer Density functional theory
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Simulation and reliability analysis of shunt active power filter based on instantaneous reactive power theory 被引量:1
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作者 CUI Yu-long LIU Hong +1 位作者 WANG Jing-qin SUN Shu-guang 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第3期416-421,共6页
This paper first discusses the operating principle of instantaneous reactive power theory. Then, the theory is introduced into shunt active power filter and its control scheme is studied. Finally, Matlab/Simulink powe... This paper first discusses the operating principle of instantaneous reactive power theory. Then, the theory is introduced into shunt active power filter and its control scheme is studied. Finally, Matlab/Simulink power system toolbox is used to simulate the system. In the simulation model, as the most common harmonic source, 3-phase thyristor bridge rectifier circuit is constructed. The simulation results before and after the shunt active filter was switched to the system corresponding to different firing angles of the thyristors are presented and analyzed, which demonstrate the practicability and reliability of the proposed shunt active filter scheme. 展开更多
关键词 Shunt active filter Instantaneous reactive power theory HARMONIC 3-phase thyristor bridge rectifier Matlab/ Simulink
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Lattice oxygen activation in transition metal doped ceria 被引量:1
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作者 Ya-Qiong Su Long Zhang +1 位作者 Valery Muravev Emiel J.M.Hensen 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第6期977-984,共8页
Density functional theory calculations were carried out to investigate the influence of doping transition metal(TM) ions into the ceria surface on the activation of surface lattice oxygen atoms. For this purpose, the ... Density functional theory calculations were carried out to investigate the influence of doping transition metal(TM) ions into the ceria surface on the activation of surface lattice oxygen atoms. For this purpose, the structure and stability of the most stable(111) surface termination of CeO2 modified by TM ions was determined. Except for Zr and Pt dopants that preserve octahedral oxygen coordination, the TM dopants prefer a square-planar coordination when substituting the surface Ce ions. The surface construction from octahedral to square-planar is facile for all TM dopants, except for Pt(1.14 e V) and Zr(square-planar coordination unstable). Typically, the ionic radius of tetravalent TM cations is much smaller than that of Ce4+, resulting a significant tensile-strained lattice and explaining the lowered oxygen vacancy formation energy. Except for Zr, the square-planar structure is the preferred one when one oxygen vacancy is created. Thermodynamic analysis shows that TM-doped CeO2 surfaces contain oxygen defects under typical conditions of environmental catalysis. A case of practical importance is the facile lattice oxygen activation in Zr-doped CeO2(111), which benefits CO oxidation. The findings emphasize the origin of lattice oxygen activation and the preferred location of TM dopants in TM-ceria solid solution catalysts. 展开更多
关键词 Lattice oxygen activation TM-doped CeO2(111) Density functional theory calculations Oxygen vacancy Square-planar coordination Coordination transformation CO oxidation
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Reaction mechanism of hydrogen activation by frustrated Lewis pairs
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作者 Lei Liu Binit Lukose +1 位作者 Pablo Jaque Bernd Ensing 《Green Energy & Environment》 SCIE CSCD 2019年第1期20-28,共9页
Typically, a Lewis acid and a Lewis base can react with each other and form a classical Lewis adduct. The neutralization reaction can however be prevented by ligating the acid and base with bulky substituents and the ... Typically, a Lewis acid and a Lewis base can react with each other and form a classical Lewis adduct. The neutralization reaction can however be prevented by ligating the acid and base with bulky substituents and the resulting complex is known as a "frustrated Lewis pair"(FLP). Since the Lewis acid and base reactivity remains in the formed complex, FLPs can display interesting chemical activities, with promising applications in catalysis. For example, FLPs were shown to function as the first metal-free catalyst for molecular hydrogen activation. This, and other recent applications of FLPs, have opened a new thriving research field. In this short-review, we recapitulate the computational and experimental studies of the H_2 activation by FLPs. We discuss the thus-far uncovered mechanistic aspects, including pre-organization of FLPs,the reaction paths for the activation, the polarization of He H bond and other factors affecting the reactivity. We aim to provide a rather complete mechanistic picture of the H_2 activation by FLPs, which has been under debate for decades since the first discovery of FLPs. This review is meant as a starting point for future studies and a guideline for industrial applications. 展开更多
关键词 Frustrated LEWIS PAIRS Hydrogen activation Reaction mechanisms Density FUNCTIONAL theory MOLECULAR dynamics simulations
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Thermal Wave Effect and Sintering Activation Energy at the Initial Stage of Field Assisted Sintering Process for Non-conductive Al_2O_3 Powders
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作者 ZHANG Long 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2018年第6期1416-1421,共6页
The effect of thermal wave at the initial stage for non-conductive Al_2 O_3 powders compact in field assisted sintering technique(FAST) was investigated. The Lord and Shulman type generalized thermoselastic theory was... The effect of thermal wave at the initial stage for non-conductive Al_2 O_3 powders compact in field assisted sintering technique(FAST) was investigated. The Lord and Shulman type generalized thermoselastic theory was introduced to describe the influence of thermal-mechanical interaction, as well as the heat transport and thermal focusing caused by thermal wave propagation. The expression of vacancy concentration difference of the particles was deduced by considering transient thermal stress. Subsequently, the relationship between activation energy and vacancy concentration difference was obtained. The mechanism of surface diffusion, volume diffusion, simultaneous surface and volume diffusion was analyzed. The numerical simulations indicate that low sintering temperature can obtain high local temperature by the superposition effect of thermal wave. Vacancy concentration differences were improved during FAST compared with hot-pressure and pressureless sintering, thereby decreasing the sintering time. By contrast, the activation energy declined with the decrease of vacancy concentration difference in the neck growth process. 展开更多
关键词 field assisted sintering technique generalized thermoelastic theory thermal wave vacancy concentration difference sintering activation energy
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DFT research on activation of sphalerite 被引量:1
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作者 孙伟 胡岳华 覃文庆 《中国有色金属学会会刊:英文版》 CSCD 2004年第2期376-382,共7页
Activation of sphalerite ZnS, (Zn, Fe)S, (Zn, Cu)S were carried out using the density functional theory(DFT) method. The electronic structures and related properties of three kind of zinc sulfide compounds were invest... Activation of sphalerite ZnS, (Zn, Fe)S, (Zn, Cu)S were carried out using the density functional theory(DFT) method. The electronic structures and related properties of three kind of zinc sulfide compounds were investigated. In addition, the relation between electronic structure and flotation behavior was discussed. The results show that, ZnS has a broader band gap than (Zn,Cu)S and (Zn,Fe)S do, and it has low electrochemistry activity to react with flotation collectors to render the surface hydrophobic. When the Zn atom in ZnS is replaced by Cu atom, the band gap will be reduced, and the top valence band will be occupied by Cu 3d orbit, thus it is beneficial to the interaction between mineral surface and collector. 展开更多
关键词 闪锌矿 活化 DFT 密度功能理论 铁闪锌矿 浮选 选矿
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