检索结果-南通市图书馆

molecular dynamics simulations of the interaction between OH radicals in plasma with poly-β-1–6-N-acetylglucosamine

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2020年第12期22卷 59-69页

作者： Shuhui YANG Tong ZHAO Jingxian CUI Zhiyun HAN Liang ZOU Xiaolong WANG Yuantao ZHANG School of Electrical Engineering Shandong UniversityJi'nan 250061People's Republic of China State Grid Shandong Electric Power Construction Company Ji'nan 250061People's Republic of China

Cold atmospheric plasma shows a satisfactory ability to inactivate bacterial biofilms that are difficult to remove using conventional methods in some cases. However, the researches on the inactivation mechanism are not quite sufficient. Poly-β-1–6-N-acetylglucosamine(PNAG),which is one of the important components in some biofilms, was used as the research subject,and the related mechanism of action triggered by different concentrations of the OH in plasma was studied using reactive molecular dynamics simulations. The results showed that OH radicals could not only trigger the hydrogen abstraction reaction leading to cleavage of the PNAG molecular structure, but undergo an OH addition reaction with PNAG molecules. New reaction pathways appeared in the simulations as the OH concentration increased, but the reaction efficiency first increased and then decreased. The simulation study in this paper could, to some extent, help elucidate the microscopic mechanism of the interaction between OH radicals in plasma and bacterial biofilms at the atomic level.

关键词： cold atmospheric plasma molecular dynamics reactive oxygen species bacterial biofilm

molecular dynamics study of coupled layer thickness and strain rate effect on tensile behaviors of Ti/Ni multilayered nanowires

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第9期30卷 400-411页

作者： Meng-Jia Su Qiong Deng Lan-Ting Liu Lian-Yang Chen Meng-Long Su Min-Rong An Fundamental Science on Aircraft Structural Mechanics and Strength Laboratory Northwestern Polytechnical UniversityXi'an 710072China School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China 1001 Factory of the Chinese People's Liberation Army Xi'an 710119China College of Materials Science and Engineering Xi'an Shiyou UniversityXi'an 710065China

Novel properties and applications of multilayered nanowires(MNWs)urge researchers to understand their mechanical behaviors *** the molecular dynamic simulation,tensile behaviors of Ti/Ni MNWs are investigated under a series of layer thickness values(1.31,2.34,and 7.17 nm)and strain rates(1.0×10^(8)s^(-1)≤ε≤5.0×10^(10)s^(-1)).The results demonstrate that deformation mechanisms of isopachous Ti/Ni MNWs are determined by the layer thickness and strain *** distinct strain rate regions in the tensile process can be discovered,which are small,intermediate,critical,and large strain rate *** the strain rate increases,the initial plastic behaviors transform from interface shear(the shortest sample)and grain reorientation(the longest sample)in small strain rate region to amorphization of crystalline structures(all samples)in large strain rate *** evolutions reveal that the disparate tensile behaviors are ascribed to the atomic fractions of different structures in small strain rate region,and only related to collapse of crystalline atoms in high strain rate region.A layer thickness-strain rate-dependent mechanism diagram is given to illustrate the couple effect on the plastic deformation mechanisms of the isopachous *** results also indicate that the modulation ratio significantly affects the tensile properties of unequal Ti/Ni MNWs,but barely affect the plastic deformation mechanisms of the *** observations from this work will promote theoretical researches and practical applications of Ti/Ni MNWs.

关键词： molecular dynamics Ti/Ni multilayered nanowires coupled layer thickness-strain rate effect plastic deformation mechanisms

molecular dynamics and Phase Behavior of Polystyrene/Poly(vinyl methyl ether) Blend in the Presence of Nanosilica

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2017年第12期35卷 1524-1539页

作者： Qi Chen 左敏 Yi-hu Song Qiang Zheng Ministry of Education Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering Zhejiang University

The variation of phase morphology, critical temperature of demixing, and molecular dynamics for polystyrene/poly（vinyl methyl ether）（PS/PVME） blends induced by hydrophilic nanosilica（A200） or hydrophobic nanosilica（R974） was investigated. With the phase separation of blend matrix, A200 migrated into PVME-rich phase due to strong interaction between A200 and PVME, while R974 moved into PS-rich phase. The thermodynamic miscibility and concentration fluctuation during phase separation of blend matrix were remarkably retarded by A200 nanoparticles due to the surface adsorption of PVME on A200, verified by the correlation length ξ near the critical region from rheological measurement and the weakened increment of reversing heat capacity（ΔCp） during glass transition via modulated differential scanning calorimetry（MDSC）. The restricted chain diffusion induced by nanosilica still occurred despite no influence of A200 and R974 on the segmental dynamics of homogenous blend matrix. The interactions between nanosilica and polymer components could restrict the terminal relaxation of blend matrix and further manipulate their phase behavior.

关键词： Phase separation Nanoparticles Rheology molecular dynamics

molecular dynamics simulation of effects of nanoparticles on frictional heating and tribological properties at various temperatures

在线全文

学校读者我要写书评

暂无评论

Friction 2020年第3期8卷 531-541页

作者： Chengzhi HU Jizu LV Minli BAI Xiaoliang ZHANG Dawei TANG Laboratory of Ocean Energy Utilization of Ministry of Education School of Energy and Power EngineeringDalian University of TechnologyDalian 116024China

The temperature of a friction pair exerts considerable influence on the tribological behavior of a *** two cases,one with and the other without Cu(copper)nanoparticles,the temperature increase in friction pairs caused by frictional heating and its tribological properties at various temperatures are studied by using the molecular dynamics *** results show that temperature distribution and surface abrasion are significantly improved by the presence of Cu *** is one of the reasons for the improvements in tribological properties achieved in the presence of *** temperature and range of influence of frictional heating for the model without nanoparticles are significantly increased with the increase in the sliding velocity;however,in the model with nanoparticles,the temperature gradient is confined to the area near the Cu *** an increase in the temperature of the friction pair,the improvement in anti-wear properties associated with the presence of Cu nanoparticles becomes more significant.

关键词： nanoparticles molecular dynamics temperature tribological properties

molecular dynamics simulation of the response of bi-disperse polyelectrolyte brushes to external electric fields

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2017年第8期26卷 521-528页

作者：张芬丁欢达段超赵双良童朝晖 Department of Physics Ningbo University College of Chemical Engineering East China University of Science and Technology

Langevin dynamics simulations have been performed to investigate the response of bi-disperse and strong polyacid chains grafted on an electrode to electric fields generated by opposite surface charges on the polyelectrolyte （PE）-grafted electrode and a second parallel electrode. Simulation results clearly show that, under a negative external electric field, the longer grafted PE chains are more strongly stretched than the shorter ones in terms of the relative change in their respective brush heights. Whereas under a positive external electric field, the grafted shorter chains collapse more significantly than the longer ones. It was found that, under a positive external electric field, the magnitude of the total electric force acting on one shorter PE chain is larger than that on one longer PE chain, or vice versa. The effects of smeared and discrete charge distributions of grafted PE chains on the response of PE brushes to external electric fields were also examined.

关键词： polyelectrolyte brushes electric fields polydispersity molecular dynamics

molecular dynamics study of hydrogen-induced cracking behavior of ferrite–pearlite gas transmission pipeline steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第2期31卷 488-500页

作者： Tao-long Xu Si-han Guo Gong-zhen He Hao-yu Han Petroleum Engineering School Southwest Petroleum UniversityChengdu610500SichuanChina Sichuan East Gas Transmission Sales Center of Sinopec Natural Gas Branch Wuhan430074HubeiChina

Hydrogen embrittlement of pipelines depends on the hydrogen-induced cracking behavior of the pipeline steel *** on molecular dynamics analysis,the ferrite–cementite(α-Fe/Fe3C)lamellar atomic structure with the Bagaryatskii orientation relationship was established,and stepwise relaxation of the conjugate gradient energy minimization and constant-temperature and constant-pressure relaxation were performed under NPT(the isothermal–isobaric)*** mechanical property curves of theα-Fe/Fe3C models were obtained under different cementite terminal plane structures,and the evolution of the atomic structure was analyzed in *** addition,the influence of different hydrogen concentrations,different temperatures,different strain rates,changes in voids,and different micro-degrees of freedom on the deformation and failure mechanism of the model was investigated,aiming to provide a reliable way to explore the micro-mechanism of macro-cracking behavior of pipeline steel.

关键词： Ferrite-cementite lamellar structure Pipeline steel Failure mechanism Crack propagation molecular dynamics

molecular dynamics study of plastic deformation mechanism in Cu/Ag multilayers

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2017年第12期26卷 444-449页

作者：田圆圆李甲胡泽英王志鹏方棋洪 State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Changsha 410082 China College of Mechanical and Vehicle Engineering Hunan University Changsha 410082 China

The plastic deformation mechanism of Cu/Ag multilayers is investigated by molecular dynamics （MD） simulation in a nanoindentation process. The result shows that due to the interface barrier, the dislocations pile-up at the interface and then the plastic deformation of the Ag matrix occurs due to the nucleation and emission of dislocations from the interface and the dislocation propagation through the interface. In addition, it is found that the incipient plastic deformation of Cu/Ag multilayers is postponed, compared with that of bulk single-crystal Cu. The plastic deformation of Cu/Ag multilayers is affected by the lattice mismatch more than by the difference in stacking fault energy （SFE） between Cu and Ag. The dislocation pile-up at the interface is determined by the obstruction of the mismatch dislocation network and the attraction of the image force. Furthermore, this work provides a basis for further understanding and tailoring metal multilayers with good mechanical properties, which may facilitate the design and development of multilayer materials with low cost production strategies.

关键词： Cu/Ag multilayers nanoindentation molecular dynamics interface

molecular dynamics Study on the Diffusion Properties of Hydrogen Atoms in Bulk Tungsten

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2013年第7期15卷 710-715页

作者：余新刚苟富均 School of Physics University of Chinese Academy of Sciences Institute of Nuclear Science and Technology Sichuan University

molecular dynamics simulations were performed to study the diffusion behavior of hydrogen atoms in body-centered cubic（bcc） tungsten（W）. The energy distribution of a single hydrogen atom in the （001） plane of tungsten lattice was computed. The values of diffusion barriers agree well with other theoretical and experimental results. The interaction between an H atom and a vacancy was simulated, which shows effect on the diffusion behavior of hydrogen an H atom to diffuse in bulk W with and evidence of strong binding effect. The temperature atoms was investigated. The critical temperature for without vacancies were calculated to be 950 K and 450 K, respectively, which is supported by several experimental results. In addition, the diffusion coefficient of hydrogen atoms in tungsten was evaluated and analyzed.

关键词： molecular dynamics tungsten hydrogen diffusion

molecular dynamics study of temperature-dependent ripples in monolayer and bilayer graphene on 6H-SiC surfaces

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2012年第6期21卷 413-420页

作者：唐超魏晓林谭歆彭向阳孙立忠钟建新 Department of Physics&Key Laboratory for Quantum Engineering and Micro-Nano Energy Technology Xiangtan University

Using classical molecular dynamics and a simulated annealing technique, we show that microscopic corrugations occur in monolayer and bilayer graphene on 6H-SiC substrates. From an analysis of the atomic configurations, two types of microscopic corrugations are identified, namely periodic ripples at room temperature and random ripples at high temperature. Two different kinds of ripple morphologies, each with a periodic structure, occur in the monolayer graphene due to the existence of a coincidence lattice between graphene and the SiC terminated surface （Si- or C-terminated surface）. The effect of temperature on microscopic ripple morphology is shown through analysing the roughness of the graphene. A temperature-dependent multiple bonding conjugation is also shown by the broad distribution of the carbon-carbon bond length and the bond angle in the rippled graphene on the SiC surface. These results provide atomic-level information about the rippled graphene layers or~ the two polar faces of the 6H-SiC substrate, which is useful not only for a better understanding of the stability and structural properties of graphene, but also for the study of the electronic properties of graphene-based devices.

关键词： ripples graphene molecular dynamics