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INTERFACIAL ATOMIC-REACTION MODEL FOR DIFFUSION BONDING OF METALS
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作者 HUANC Yan CUI Jianzhong MA Longxiang Northeast University of Technology,Shenyang 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1992年第10期268-273,共6页
According to probability theory and atomic activation on bonding interface of metals, a mathematical model was developed for the atomic interfacial reaction during diffusion bonding.The effect of parameters of bonding... According to probability theory and atomic activation on bonding interface of metals, a mathematical model was developed for the atomic interfacial reaction during diffusion bonding.The effect of parameters of bonding processing and material on the bonding strength was then gained.It was suggested that the activation centre of atomic interfacial reaction of bonding may be,in situ,the boundary dislocation and its elastic stress field. A substantial agreement about the quantitative prediction of the model was made with the results of diffusion bonding experiments for 7075Al alloy 展开更多
关键词 diffusion bonding atomic reaction Al alloy
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Laser Ablation Atomic Beam Apparatus with Time-Sliced Velocity Map Imaging for Studying State-to-State Metal Reaction Dynamics
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作者 董常武 刘嘉兴 +1 位作者 李芳芳 王凤燕 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2016年第1期99-104,I0002,共7页
We report a newly constructed laser ablation crossed molecular beam apparatus, equipped with time-sliced velocity map imaging technique, to study state-to-state metal atom reaction dynamics. Supersonic metal atomic be... We report a newly constructed laser ablation crossed molecular beam apparatus, equipped with time-sliced velocity map imaging technique, to study state-to-state metal atom reaction dynamics. Supersonic metal atomic beam is generated by laser vaporization of metal rod, and free expansion design without gas flow channel has been employed to obtain a good quality of metal atomic beam. We have chosen the crossed-beam reaction Al+O2 to test the performance of the new apparatus. Two-rotational-states selected AIO(X^2∑+, v=0, N and N+I4) products can be imaged via P(N) and R(N+14) branches of the Av=l band at the same wavelength, during (1+1) resonance-enhanced multi-photon ionization through the AIO(D2E+) intermediate state. In our experiment at 244.145 nm for simultaneous transitions of P(15) and R(29) branch, two rings in slice image were clearly distinguishable, corresponding to the AiO(v=0, N=IS) and AIO(v=0, N=29) states respectively. The energy difference between the two rotational levels is 403 cm^-1. The success of two states resolved in our apparatus suggests a better collisional energy resolution compared with the recent research study [J. Chem. Phys. 140, 214304 (2014)]. 展开更多
关键词 Time-sliced velocity map imaging Crossed beam Laser ablation Metal atom reaction dynamics
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Visualization of atomic scale reaction dynamics of supported nanocatalysts during oxidation and ammonia synthesis using in-situ environmental(scanning) transmission electron microscopy
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作者 Michael R.Ward Robert W.Mitchell +1 位作者 Edward D.Boyes Pratibha L.Gai 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第6期281-290,I0007,共11页
Reaction dynamics in gases at operating temperatures at the atomic level are the basis of heterogeneous gas-solid catalyst reactions and are crucial to the catalyst function.Supported noble metal nanocatalysts such as... Reaction dynamics in gases at operating temperatures at the atomic level are the basis of heterogeneous gas-solid catalyst reactions and are crucial to the catalyst function.Supported noble metal nanocatalysts such as platinum are of interest in fuel cells and as diesel oxidation catalysts for pollution control,and practical ruthenium nanocatalysts are explored for ammonia synthesis.Graphite and graphitic carbons are of interest as supports for the nanocatalysts.Despite considerable literature on the catalytic processes on graphite and graphitic supports,reaction dynamics of the nanocatalysts on the supports in different reactive gas environments and operating temperatures at the single atom level are not well understood.Here we present real time in-situ observations and analyses of reaction dynamics of Pt in oxidation,and practical Ru nanocatalysts in ammonia synthesis,on graphite and related supports under controlled reaction environments using a novel in-situ environmental(scanning) transmission electron microscope with single atom resolution.By recording snapshots of the reaction dynamics,the behaviour of the catalysts is imaged.The images reveal single metal atoms,clusters of a few atoms on the graphitic supports and the support function.These all play key roles in the mobility,sintering and growth of the catalysts.The experimental findings provide new structural insights into atomic scale reaction dynamics,morphology and stability of the nanocatalysts. 展开更多
关键词 In-situ visualization atomic scale reaction dynamics In-situ environmental scanning transmission electron microscopy with single atom resolution Supported nanoparticles Ammonia synthesis Oxidation reactions
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Imaging Reaction Dynamics of Y+SO2
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作者 Dong Yan Yu-jie Ma +3 位作者 Fang-fang Li Jia-xing Liu Guan-jun Wang Feng-yan Wang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2020年第2期239-242,I0003,共5页
The reaction dynamics of yttrium atoms with sulfur dioxide molecules at a high collision energy of 36 kcal/mol was studied using time-sliced velocity map ion imaging,crossed molecular beam and laser-ablation method.Th... The reaction dynamics of yttrium atoms with sulfur dioxide molecules at a high collision energy of 36 kcal/mol was studied using time-sliced velocity map ion imaging,crossed molecular beam and laser-ablation method.The product YO was detected via multiphoton ionization at various wavelengths in the region of 482-615 nm.The slice images of YO show a broad velocity distribution and forward-backward peaking angular distribution.The forward scattering signal is stronger than its backward distribution.This indicates that the reaction proceeds via an intermediate complex and the lifetime of the intermediate state is less than one rotational period.The formation of complex suggests that electron transfer occurs in the oxidation reaction. 展开更多
关键词 Time-sliced velocity map imaging CROSSED-BEAM Laser ablation Metal atom reaction dynamics SO2
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Advanced Techniques for Quantum-State Specific Reaction Dynamics of Gas Phase Metal Atoms
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作者 Ang Xu Yu-jie Ma +3 位作者 Dong Yan Fang-fang Li Jia-xing Liu Feng-yan Wang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2021年第1期61-70,I0011,共11页
One of the themes of modern molecular reac tion dynamics is to charac terize elementary chemical reactions from“quan tum state to quan tum stat e”,and the study of molecular reaction dynamics in excited states can h... One of the themes of modern molecular reac tion dynamics is to charac terize elementary chemical reactions from“quan tum state to quan tum stat e”,and the study of molecular reaction dynamics in excited states can help test the validi ty of modern chemical t heories and provide met hods to cont rol chemical reactions.The subject of this review is to describe the recent experimental techniques used to study the reaction dynamics of metal atoms in the gas phase.Through these techniques,information such as the internal energy distribution and angular distribution of the nascent products or the three-dimensional stereodynamic reactivity can be obtained.In addition,by preparing metal at oms wi th specific exci ted elec tronic states or orbi tal arrangemen ts,information about the reactivity of the electronic states enriches the relevant understanding of the electron transfer mechanism in metal reaction dynamics. 展开更多
关键词 Time-sliced ion velocity map imaging Crossed molecular beams Laser ablation Metal atom reaction dynamics STEREODYNAMICS
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Laser Polarization Orientations in(e,2e)Reactions in Atoms
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作者 Ajana I. Makhoute A. Khalil D. 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第8期62-65,共4页
Second-order Born calculations are performed to investigate the triple differential cross sections of coplanar asymmetric laser-assisted (e, 2e) collisions for hydrogen and helium targets. The incident electron is c... Second-order Born calculations are performed to investigate the triple differential cross sections of coplanar asymmetric laser-assisted (e, 2e) collisions for hydrogen and helium targets. The incident electron is considered to be dressed by the laser field in a nonperturbative manner by choosing the Volkov solutions in both the initial and final channels. Detailed calculations of the scattering amplitudes are performed using the Sturmian basis expansion. The state of the ejected electron is described by a Coulomb-Volkov wave function. Two geometries are investigated in which the laser polarization vector is either parallel to the incident momentum of the projectile or parallel to the momentum transfer. Our numerical results show that, in the low energy range, these two laser polarization orientations give the same shape and the same order of magnitude of laser-assisted ionization cross sections of helium and hydrogen targets. 展开更多
关键词 Laser Polarization Orientations in e 2e)reactions in Atoms
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Hydrogen Abstraction Reaction Mechanisms and Rate Constants for Isoflurane with a Cl Atom at 200~2000 K:A Theoretical Investigation
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作者 任宏江 杨晓慧 +2 位作者 李小军 李江涛 杨菊香 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2015年第9期1317-1327,共11页
The kinetics and mechanisms of H abstraction reaction between isoflurane and a CI atom have been investigated using DFT and G3(MP2) methods of theory. The geometrical structures of all species were optimized by the ... The kinetics and mechanisms of H abstraction reaction between isoflurane and a CI atom have been investigated using DFT and G3(MP2) methods of theory. The geometrical structures of all species were optimized by the wB97XD/6-311++G** method. Intrinsic reaction coordinate (IRC) analysis has been carried out for the reaction channels. Thermochemistry data have been obtained by utilizing the high accurate model chemistry method G3(MP2) combined with the standard statistical thermodynamic calculations. Gibbs free energies were used for reaction channels analysis. Two channels were obtained, which correspond to P(1) and P(2). The rate constants for the two channels over a wide temperature range of 200-2000 K were also obtained. The results show that the barriers of P(1) and P(2) reaction channels are 50.36 and 50.34 kJ/mol, respectively, predicting that it exists two competitive channels. The calculated rate constant is in good agreement with the experiment value. Additionally, the results also show that the rate constants also increase from 1.85x10^-16 to 2.16x 10^12 cm3.moleculel.s-1 from 200 to 2000 K 展开更多
关键词 isoflurane CI atom reaction mechanisms rate constants G3(MP2)
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Kinetics Characteristics and Bremsstrahlung of Argon DC Discharge Under Atmospheric Pressure 被引量:4
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作者 何为 刘兴华 +4 位作者 咸日常 陈素红 廖瑞金 杨帆 肖汉光 《Plasma Science and Technology》 SCIE EI CAS CSCD 2013年第4期335-342,共8页
An improved self-consistent, multi-component, and one-dimensional plasma model for simulating atmospheric pressure argon glow discharge is presented. In the model, both the plasma hydrodynamics model and chemical mode... An improved self-consistent, multi-component, and one-dimensional plasma model for simulating atmospheric pressure argon glow discharge is presented. In the model, both the plasma hydrodynamics model and chemical model are considered. The numerical simulation is carried out for parallel-plate geometry with a separation of 0.06 cm. The results show that Ar* plays a major role in the discharge, which is mainly produced by ground state excitation reaction. The electron temperature reaches its maximum in the cathode sheath but maintains a low value (0.23 eV) in bulk plasma. Elastic collision is the dominant volumetric electron energy loss in atmosphere argon glow discharge, which is negligible in low pressure argon glow discharge. The metastable step-wise ionization is the main mechanism for electron production to sustain the discharge. However, the highest contribution to electron production rate is ground state ionization reaction. The bremsstrahlung power density is related to electric voltage. With the increase of the electric voltage, the bremsstrahlung power density increases, namely, the strength of ultraviolet radiation spectrum enhances in the cathode sheath. 展开更多
关键词 atmospheric pressure glow discharge plasma model metastable argon atom ionization reaction bremsstrahlung power density
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Mechanism and rate constants for complete series reactions of 19 fluorophenols with atomic H 被引量:1
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作者 Rui Gao Xiaoyan Sun +2 位作者 Wanni Yu Qingzhu Zhang Wenxing Wang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2014年第1期154-159,共6页
Fluorine-containing halogenated fluorophenol may have effect as intermediate species involved in the formation of polyfluorinated dibenzo-p-dioxin/dibenzofurans (PFDDs/Fs). The mechanism for the atomic H initiated r... Fluorine-containing halogenated fluorophenol may have effect as intermediate species involved in the formation of polyfluorinated dibenzo-p-dioxin/dibenzofurans (PFDDs/Fs). The mechanism for the atomic H initiated reactions with complete series of nineteen fluorophenol congeners was studies using the density functional theory. At the MPWB1K,/6-31+G(d,p) level, the geometries and frequencies of reactants, transition states, and products were obtained, and the accurate energetic values were acquired at the MPWB 1K/6-311 +G(3df,2p) level. The rate constants were evaluated by the canonical variational transition-state theory with the small curvature tunneling contribution over a wide temperature range of 600-1000 K. The study shows that the intramolecular hydrogen-bond in the ortho-substituted FPs as well as the inductive effect of the electron-withdrawing fluorine and steric repulsion of multiple substitutions may ultimately be responsible for the relative strength of the O-H bonds in FPs. The results can be used for further studies on PFDD/Fs formation mechanism. 展开更多
关键词 fluorophenols fluorophenoxy radicals atomic H hydrogen bond reaction mechanism rate constants
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Theoretical study on the degradation reaction of octachlorinated dibenzo-p-dioxin with atomic oxygen o(3P) in dielectric barrier discharge reactor 被引量:1
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作者 Chen Gong Xiaomin Sun +2 位作者 Chenxi Zhang Jingtian Hu Chuansong Qi 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2014年第11期2283-2289,共7页
Dielectric barrier discharges (DBD) have been used in the degradation of dioxins due to the large number of excimers and free radicals produced in discharge process. In this article, the density functional theory (... Dielectric barrier discharges (DBD) have been used in the degradation of dioxins due to the large number of excimers and free radicals produced in discharge process. In this article, the density functional theory (DFT) is used to study the degradation mechanism of octachlorinated dibenzo-p-dioxin (OCDD) with the atomic oxygen O(3P) in DBD reactor. The reactants, intermediates, transition states and products are optimized at the MPWB1K/6- 31 + G(d,p) level. The vibrational frequencies have been calculated at the same level. The reaction pathways and mechanisms are analyzed in detail. The effect of removing the chlorine atom on environment also has been discussed. 展开更多
关键词 OCDD Dechlorination reaction Dielectric barrier discharge atomic oxygen
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Metallurgical microstructure control in metal-silicon reactions 被引量:3
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作者 TU KingNing TANG Wei 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第3期505-519,共15页
A comprehensive review on interfacial reactions to form silicides between metal and Si nanowire or wafer is given.Formation of silicide contacts on Si wafers or Si nanowires is a building block needed in making curren... A comprehensive review on interfacial reactions to form silicides between metal and Si nanowire or wafer is given.Formation of silicide contacts on Si wafers or Si nanowires is a building block needed in making current-based Si devices.Thus,the microstructure control of silicide formation on the basis of kinetics of nucleation and growth has relevant applications in microelectronic technology.Repeating events of homogeneous nucleation of epitaxial silicides of Ni and Co on Si in atomic layer reaction is presented.The chemical effort on intrinsic diffusivities in diffusion-controlled layer-typed intermetallic compound growth of Ni2Si is analyzed. 展开更多
关键词 NUCLEATION atomic layer reaction nano-gap intermetallic compound Wagner diffusivity
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Solvent effects on oxygen atom transfer reaction between manganese(V)-oxo corrole and alkene 被引量:1
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作者 Lan Yu Qi Wang +5 位作者 Lu Dai Wei-Ying Li Rong Chen Mian HR Mahmood Hai-Yang Liu Chi-Kwong Chang 《Chinese Chemical Letters》 SCIE CAS CSCD 2013年第6期447-449,共3页
Pseudo-first order reaction rate constants of 5,10,15-tris(pentafluorophenyl)corrole Mn(V)-oxo (F_(15)CMn(V)-oxo),5,15-bis(pentafluorophenyl)-10-(phenyl)corrole Mn(V)-oxo(F_(10)CMn(V)-oxo),5,15- ... Pseudo-first order reaction rate constants of 5,10,15-tris(pentafluorophenyl)corrole Mn(V)-oxo (F_(15)CMn(V)-oxo),5,15-bis(pentafluorophenyl)-10-(phenyl)corrole Mn(V)-oxo(F_(10)CMn(V)-oxo),5,15- bis(phenyl)-10-(pentafluorophenyl)corrole Mn(V)-oxo(F_5CMn(V)-oxo) and 5,10,15-tris(phenyl)corrole Mn(V)-oxo(F_0CMn(V)-oxo) with a series of alkene substrates in different solvents were determined by UV-vis spectroscopy.The results indicated that the oxygen atom transfer pathway between Mn(V)-oxo corrole and alkene is solvent-dependent. 展开更多
关键词 Corrole Mn(V)-oxo corrole Oxygen atom transfer reaction Solvent effect
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Exact quantum calculations on the collinear hydrogen atom transfer reaction——I. Study on oscillations of the reaction probabilities of Cl+HCl
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作者 JU Guan-Zhi CHEN De-Zhan 《Acta Chimica Sinica English Edition》 SCIE CAS CSCD 1989年第6期496-503,共1页
1-D quantum calculations of reaction probabilities have been carried out for the col- linear reaction Cl+HCl (v≤3)→ClH (v'≤3)+Cl using hyperspherical coordinates. An LEPS po- tential energy surface with a shallow ... 1-D quantum calculations of reaction probabilities have been carried out for the col- linear reaction Cl+HCl (v≤3)→ClH (v'≤3)+Cl using hyperspherical coordinates. An LEPS po- tential energy surface with a shallow well depth of -3.22 KJ/mol has been used in the calculations. The state-to-state reaction probabilities have been calculated. According to the results obtained we found that the diagonal (v=v') reaction probabilities dominate over the off-diagonal (vv') reaction probabilities and the largest off-diagonal reaction probabilities are smaller than 0.1. The reaction probabilities show oscillation as a function of energy. Dynamic resonances strengthen for the potential energy surface with a well. 展开更多
关键词 Exact quantum calculations on the collinear hydrogen atom transfer reaction HCI Study on oscillations of the reaction probabilities of Cl+HCl
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