A reactive molecular dynamics simulation of the silica-water interface

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物理学英文词汇

物理专业英语词汇(M)Favorite m center m 中心mach angle 马赫角mach cone 马赫锥mach number 马赫数mach wave 马赫波mach zehnder interferometer 马赫曾德耳干涉仪mach's principle 马赫原理machine language 机骑言machine oriented language 面向机颇语言macleod gage 麦克劳计macro crystal 粗晶macrography 宏观照相术macroinstability 宏观不稳定性macromolecule 高分子macron 宏观粒子macroparticle 宏观粒子macrophysics 宏观物理学macroscopic brownian motion 宏观布朗运动macroscopic particle 宏观粒子macroscopic quantization 宏观量子化macroscopic system 宏观系统macrostate 宏观态macrostructure 宏观结构macrosystem 宏观系统magdeburg hemispheres 马德堡球magellanic clouds 麦哲伦星系magellanic galaxy 麦哲伦星系magic eye 光党指示管magic lantern 幻灯magic number 幻数magic t t 形波导支路magma 岩浆magneli structure 马格涅利结构magnesium 镁magnet 磁铁magnetic 磁的magnetic amplifier 磁放大器magnetic analyzer 磁分析器magnetic anisotropy 磁蛤异性magnetic anomaly 磁异常magnetic axis 磁轴magnetic balance 磁力天平magnetic birefringence 磁双折射magnetic breakdown 磁哗magnetic bubble 磁泡magnetic bubble storage 磁泡存储器magnetic character figure 磁特正magnetic charge 磁荷magnetic chart 磁图magnetic circuit 磁路magnetic conductance 磁导magnetic core storage 磁芯存储器magnetic current 磁流magnetic declination 磁偏角magnetic deflection 磁偏转magnetic deflection mass spectrometer 磁偏转型质谱仪magnetic dip 磁倾角magnetic dipole 磁偶极子magnetic dipole moment 磁偶极矩magnetic dipole radiation 磁偶极辐射magnetic disk 磁盘magnetic disturbances 磁扰magnetic domain 磁畴magnetic domain walls 磁畴壁magnetic drum 磁鼓magnetic elements 磁元magnetic energy 磁能magnetic entropy 磁熵magnetic equator 磁赤道magnetic field 磁场magnetic field energy 磁场能量magnetic field intensity 磁场强度magnetic field strength 磁场强度magnetic fluid 磁铃magnetic flux 磁通量magnetic flux compression 磁通量紧缩magnetic flux density 磁通密度magnetic flux quantization 磁通量量子化magnetic fluxmeter 磁通量计magnetic focusing 磁致聚焦magnetic force 磁力magnetic head 磁头magnetic hysteresis 磁滞magnetic image 磁象magnetic inclination 磁倾角magnetic induction 磁感应magnetic induction flux 磁感应束magnetic kerr effect 克尔氏磁效应magnetic latitude 磁纬度magnetic leakage 磁漏magnetic lens 磁透镜magnetic line of force 磁力线magnetic loss 磁损耗magnetic map 磁图magnetic material 磁性材料magnetic memory 磁存储器magnetic mirror 磁镜magnetic moment 磁矩magnetic monopole 磁单极子magnetic needle 磁针magnetic north 磁北magnetic permeability 磁导率magnetic perturbation 磁扰magnetic point group 磁点群magnetic polarization 磁极化magnetic polaron 磁极化子magnetic pole 磁极magnetic potential 磁势magnetic pressure 磁压magnetic prism 磁棱镜magnetic probe 磁探针magnetic prospecting 磁法勘探magnetic quantum number 磁量子数magnetic recorder 磁记录器magnetic recording 磁记录magnetic refrigeration 磁冷却magnetic refrigerator 磁致冷机magnetic relaxation 磁弛豫magnetic reluctance 磁阻magnetic remanence 顽磁magnetic resistance 磁阻magnetic resonance 磁共振magnetic reynolds number 磁雷诺数magnetic rigidity 磁刚性magnetic rotatory dispersion 磁致旋光色散magnetic saturation 磁饱和magnetic semiconductor 磁性半导体magnetic separation 磁力选矿magnetic shell 磁壳magnetic shield 磁屏蔽magnetic sound recording 磁录音magnetic space group 磁空间群magnetic spectrometer 磁谱仪magnetic spin quantum number 自旋磁量子数magnetic star 磁星magnetic store 磁存储器magnetic storm 磁暴magnetic structure 磁结构magnetic substance 磁体magnetic superconductor 磁超导体magnetic surface 磁面magnetic susceptibility 磁化率magnetic tape 磁带magnetic thermometer 磁温度计magnetic thin film 磁薄膜magnetic torque 磁转矩magnetic transition 磁跃迁magnetic trap 磁阱magnetic variable 磁变星magnetic variable star 磁变星magnetic variations 磁变magnetic viscosity 磁粘滞性magnetics 磁学magnetism 磁magnetization 磁化magnetization curve 磁化曲线magnetization vector 磁化矢量magnetized black hole 磁化黑洞magnetizing 磁化magnetizing coil 磁化线圈magnetizing current 磁化电流magnetizing force 磁化力magneto aerodynamics 磁空气动力学magneto optic effect 磁光效应magneto oscillatory absorption 磁振荡吸收magneto rotation 磁致旋光magneto volume effect 磁体积效应magnetoacoustic effect 磁声效应magnetoacoustic wave 磁声波magnetocaloric effect 磁热效应magnetochemistry 磁化学magnetocircular dichroism 磁圆二向色性magnetodielectric 磁性电介质magnetodiode 磁敏二极管magnetoelastic effect 磁弹性效应magnetoelastic wave 磁弹性波magnetoelectricity 磁电学magnetogram 磁强记录图magnetograph 磁强记录仪magnetohydrodynamic instability 磁铃力学不稳定性magnetohydrodynamic wave 磁铃波magnetohydrodynamics 磁铃动力学magnetology 磁学magnetomechanical factor 磁力学因数magnetomechanics 磁力学magnetometer 磁强计magnetomotive force 磁通势magneton 磁子magnetooptics 磁光学magnetophotophoresis 磁光致泳动magnetoplasma 磁等离子体magnetoplasmadynamics 磁等离子体动力学magnetoplumbite 氧化铅铁淦氧磁体magnetopolaron 磁极化子magnetoreflection 磁反射magnetoresistance 磁阻效应magnetoresistor 磁致电阻器magnetosphere 磁层magnetostatic field 静磁场magnetostatics 静磁学magnetostriction 磁致伸缩magnetostriction oscillator 磁致伸缩振荡器magnetostrictive effect 磁致伸缩效应magnetothermal effect 磁致热效应magnetothermoelectric effect 磁致热电效应magnetron 磁控管magnetron vacuum gage 磁控管真空计magnification 放大率magnifier 放大镜magnifying glass 放大镜magnitude 量magnitude of the eclipse 食分magnon 磁振子magnus effect 马格努斯效应main quantum number 挚子数main sequence 烛main sequence stars 烛星main storage 宙储器major planets 大行星majorana force 马约喇纳力majorana neutrino 马约喇纳中微子majorana particle 马约喇纳粒子majorana spinor 马约喇纳旋量majority carrier 多数载劣majoron 马约喇纳量子maksutov telescope 马克苏托夫望远镜malleability 展性malter effect 马尔特效应malus law 马吕斯定律man made satellite 人造卫星mandelstam representation 曼德尔斯坦表象mandrin 细探针manganese 锰manganin 锰镍铜合金manifold 廖manipulator 机械手manometer 压力表manoscope 气体密度计manoscopy 气体密度测定manostat 稳压器mantle 地幔mantle convection 地幔对流mantle rayleigh wave 地幔瑞利波manual 手册many body force 多体力many body problem 多体问题many body system 多体系many wave approximation 多波近似mare 海margin 余量margin of error 误差范围margin of safety 安全因子marginal rays 边缘光线marine physics 海洋物理学mariner project 马里纳计划marisat system 海洋卫星系统mark 标记markoff chain 马尔柯夫链markoff process 马尔柯夫过程marriage of cable and satellites 电缆和人造卫星的联接mars 火星martensite 马氏体maser 微波激射器脉塞mass 质量mass absorption coefficient 质量吸收系数mass analysis 质量分析mass analyzer 质谱仪mass defect 质量筐mass effect 聚集效应mass energy conversion formula 质能换算公式mass energy equivalence principle 质能相当性原理mass energy relation 质能关系mass filter 滤质器mass flowmeter 质量量计mass formula 质量公式mass luminosity relation 质量发光度关系mass number 质量数mass renormalization 质量重正化mass separator 质量分离器mass shell 质壳mass spectrograph 质谱仪mass spectrometer 质谱仪mass spectroscopy 质谱法mass spectrum 质谱mass stopping power 质量阻止本领mass transfer 质量传递mass unit 质量单位massey criterion 梅涡据master equation 纸程master gyroscope 自由陀螺仪matching 匹配material 物质material point 质点material wave 物质波materials science 材料科学materials testing reactor 材料试验反应堆mathematical crystallography 数学晶体学mathematical expectation 数学期望值mathematical pendulum 单摆mathematical physics 数学物理mathematical programming 数学规划mathieu functions 马提厄函数matrix mechanics 矩阵力学matrix representation 矩阵表示matter 物质matter dominated universe 物质为诸宙matter wave 德布罗意波matthias rule 马赛厄斯定则matthiessen rule 马苇定则maupertuis' principle 莫佩尔秋原理maximum deviation 最大偏差maximum load 最大负载maximum lyapunov index 最大李亚普诺夫指数maximum permissible concentration 最大容许浓度maximum permissible dose 最大容许剂量maximum postulated accident 最大假设事故maximum speed 最大速度maximum stress 最大应力maximum temperature 最高温度maximum thermometer 最高温度表maximum velocity 最大速度maxwell 麦克斯韦maxwell boltzmann distribution 麦克斯韦玻耳兹曼分布maxwell boltzmann statistics 麦克斯韦玻耳兹曼统计maxwell bridge 麦克斯韦电桥maxwell demon 麦克斯韦妖maxwell field 麦克斯韦场maxwell relations 麦克斯韦关系maxwell velocity distribution 麦克斯韦的速度分布maxwell's distribution law 麦克斯韦分布律maxwell's equations 麦克斯韦方程maxwellian distribution 麦克斯韦分布maxwellmeter 磁通计mb 微巴mean acceleration 平均加速度mean deviation 平均偏差mean ergodic theorem 平均脯历经定理mean error 平均误差mean free path 平均自由程mean life 平均寿命mean lifetime 平均寿命mean solar day 平太阳日mean solar time 平太阳时mean square error 均方误差mean sun 平太阳mean value 平均值mean velocity 平均速度mean velosity 平场速度measure 测度measurement 测量measurement error 测量误差measuring 测量measuring apparatus 测量仪器measuring eyepiece 目镜测微计measuring instrument 测试仪器度量仪表measuring method 测量法measuring technique 测量技术mechanical energy 力学能mechanical equivalent of heat 热功当量mechanical filter 机械滤波器mechanical monochromator 机械单色器mechanical motion 力学运动mechanical system 力学系mechanical vibrations 机械振动mechanical world view of nature 机械的自然观mechanics 力学mechanism 机构mechanocaloric effect 机械热效应mechanochemistry 机械化学mechanoelectric conversion 机电变换mechanostriction 机致伸缩mechnical equivalent of light 光功当量medical electronics 医疗电子学medical physics 医用物理学medium 介质medium energy electron diffraction 中能电子衍射medium energy electron scattering spectroscopy 中能电子散射能谱学mega 兆mega electron volt 兆电子伏megacycle 兆周megawatt 兆瓦megger 高阻表megohm 兆欧meissner effect 迈斯纳效应meldometer 熔点测定计melt growth 熔体生长melting 熔化melting heat 熔化热melting point 熔点melting temperature 熔解温度membrane 膜memory 存储;记忆memory capacity 存储容量memory cell 存储单元memory effect 记忆效应memory register 存储寄存器mendeleev's periodic law 门捷列夫周期律mendelevium 钔meniscus 弯月面meniscus lens 弯月透镜mensa 山案座mercury 水星;水银mercury arc lamp 水银灯mercury arc rectifier 汞弧整流mercury barometer 水银气压表mercury cell 汞电池mercury diffusion pump 汞扩散泵mercury i chloride structure 氯化汞i型结构mercury relay 水银继电器mercury telemetry 水星遥测术mercury thermometer 水银温度表mercury vacuum gage 水银真空计mercury vapor lamp 水银灯meridian 子午线meridian passage 中天meridian transit 中天meridional ray 子午光线mesa transistor 台面型晶体管mesoatom 介子原子mesodynamics 介子动力学mesomolecule 介子分子mesomorphic state 介晶态meson 介子meson factory 介子工厂meson theory 介子理论meson theory of nuclear forces 核力的介子理论mesonic atom 介子原子mesonic molecule 介子分子mesopic vision 黄昏黎糜觉mesoscopic effect 介观效应mesosphere 中间层messier catalog 梅味星云星团表metacenter 定倾中心metal 金属metal film resistor 金属薄膜电阻器metal foil 金属箔metal insulator semiconductor light emitting diod 金属绝缘膜半导体发光二极管metal insulator transition 金属绝缘体跃迁metal nonmetal transition 金属非金属跃迁metal organic compound 有机金属化合物metal oxide semiconductor structure mos 结构metal vapor laser 金属蒸汽激光器metallic 金属的metallic binding 金属键metallic bond 金属键metallic crystal 金属晶体metallic element 金属元素metallic glass 金属玻璃metallic lustre 金属光泽metallic microcluster 金属微簇metallic reflection 金属反射metallic thin film 金属薄膜metallic valence 金属原子价metallized paper capacitor 镀金属纸介电容器metallography 金相学metallomicroscope 金相显微镜metallurgy 冶金学metamagnetism 亚磁性metastability 亚稳定性metastable atom 亚稳原子metastable equilibrium 亚稳平衡metastable level 亚稳能级metastable molecule 亚稳分子metastable nucleus 亚稳核metastable phase 亚稳相metastable state 亚稳状态meteor 燎meteor astronomy 燎天文学meteor camera 燎照相机meteor shower 燎雨meteor stream 燎群meteoric dust 燎尘meteoric iron 陨铁meteoric stone 石陨星meteorite 陨星meteorite crater 陨星坑meteoritic iron 陨铁meteoritics 陨石学meteorological acoustics 气象声学meteorological optics 气象光学meteorological radar 气象雷达meteorological satellite 气象卫星meteorological thermodynamics 气象热力学meteorology 气象学meter 米meter convention 米条约meter standard 米原器meter wave 米波metering 计量metglass 金属玻璃method 方法method of approximation 近似法method of crystal projection 晶体投影法method of difference 差分法method of images 镜象法method of iteration 迭代法method of least squares 最小二乘法method of measurement 测量法method of molecular orbitals 分子轨迹法method of perturbation 微扰法method of steepest descent 最陡下降法method of successive approximation 逐次逼近法method of undetermined coefficients 待定系数法metonic cycle 太阴周metre 米metre wave 米波metric 度规metric space 度量空间metric system 米制metric tensor 度规张量metrology 计量学metronome 节拍器mhd arc mpd 弧光mho 闻子mica 云母micelle 胶体微粒michel parameter 米歇尔参数michelson interferometer 迈克耳逊干涉仪michelson morley experiment 迈克耳逊莫雷实验michelson stellar interferometer 迈克耳逊恒星干涉计micro 微microaccelerometer 微加速计microaerotonometer 微量气体张力计microampere 微安microanalysis 微量化字分析microbalance 微量天平microbar 微巴microcanonical ensemble 微正则系综microchemical analysis 微量化字分析microchemistry 微量化学microcomputer 微型计算机microcrystal 微晶microcrystalline 微晶的microcrystallography 微观结晶学microengineering 微工程学microfarad 微法microfield 微场microfilm 缩微胶片micrography 显微照相术microinstability 微不稳定性microlaser 微型激光器microlock 卫星遥测系统micromagnetics 微磁学micromanometer 微压力计micrometer 测微计micrometer microscope 测微显微镜micrometron 自动显微镜micromicrocurie 微微居里micromicrofarad 微微法micron 微米microoscillograph 显微示波仪microparticle 微观粒子microphone 传声器microphotograph 显微镜照片microphotometer 测微光度计microphysics 微观物理学microplasma 微等粒子体microprobe 微探针microprogram 微程序microprojector 显微投影仪micropyrometry 微测高温术microscope 显微镜microscopic brownian motion 微观布朗运动microscopic particle 微观粒子microscopic state 微观状态microscopic system 微观系统microscopium 显微镜座microsecond 微秒microseismics 微地震学microseismograph 微震记录仪microspectrofluorimeter 显微荧光光谱仪microspectrograph 显微光谱仪microspectrophotometry 显微分光光度学microspectroscope 显微分光镜microspectroscopy 显微光谱学microstate 微观状态microstructure 显微结构microsystem 微观系统microtelescope 显微望远镜microthermometer 微温度计microthermometry 显微温度学microtron 电子回旋加速器microwave 微波microwave circuit 微波电路microwave diode 微波二极管microwave method 微波法microwave resonator 微波谐振器microwave spectroscopy 微波谱学microwave spectrum 微波频谱microwave transistor 微波晶体管microwave tube 微波电子管microwave ultrasound 微波超声microwave weapon 微波武器mie scattering 米散射migdal approximation 米格达尔近似migration length 迁移长度mil 密耳mile 英里milky way 银河miller index 密勒指数miller's notation 密勒记号milli 毫milliampere 毫安millibar 毫巴millimeter 毫米millimeter wave 毫米波millimetre 毫米million electorn volt 兆电子伏millisecond 毫秒millivolt 毫伏millivoltmeter 毫状计mimosa seismic foreteller 含羞草地震预报器miniature tube 微型管miniature valve 微型管minicomputer 小型计算机miniinfraredtracer 微型红外示踪器minilaser 微型激光器minimal interaction 最小耦合相互酌minimax principle 极大极小原理minimum b field 最小磁场minimum deviation 最小偏向minimum entropy production 最小熵产生minimum thermometer 最低温度表minkowski space time 闵科夫斯基时空minor planet 小行星minority carrier 少数载劣minus 减minus sign 减号minute 分mira stars 刍藁变星mira type variables 刍藁变星mirage 蜃景mirror field 磁镜场mirror nuclei 镜象核mirror reflection 镜反射mirror surface 镜面mirror telescope 反射望远镜misfit dislocation 错配位错missile 导弹missing line 丢失线missing mass 暗物质mistake 错误mixed crystal 混合晶体mixed state 混合态mixer diode 基模mixer tube 混频管mixing length 混合长度mixing ratio 混合比mixture 混合物mks system of units mks 单位制;mks单位制mksa system of units mksa 单位制mobile laser tracking station 移动激光追踪站mobility 迁移率mobility of ions 离子迁移率mode 模mode coupling 模耦合mode locked laser 锁模激光器mode locking 锁模mode of oscillation 振动型mode of vibration 振动型mode pulling 波模牵引model 模型model of nucleus 核模型model of the galaxy 银河系模型moderated neutron 慢化中子moderation 减速moderation of neutrons 中子减速moderator 减速剂modern biology 现代生物学modern physics 现代物理学modification 变形modular invariance 模数不变性modulated structure 灯结构modulation 灯modulation method 灯法modulation spectroscopy 灯光谱学modulation transfer function 灯传递函数modulator type vacuum gage 灯仆真空计module 模件modulus 模数modulus of elasticity 弹性模数modulus of rigidity 剪切殚性模量moffatt's vortex 莫法特涡旋mohoroviris discontinuity 莫霍洛维奇不连续性mohs hardness 莫氏硬度moist labile energy 潮湿不稳能moisture examining instrument 水气检查仪mol 克分子molar fraction 克分子分率molar heat 分子热molar polarization 克分子极化molar refraction 分子折射molar susceptibility 克分子磁化率molar volume 克分子体积molding 制模mole 克分子mole fraction 克分子分率molectronics 分子电子学molecular absorption coefficient 分子吸收系数molecular acoustics 分子声学molecular astronomy 分子天文学molecular beam 分子束molecular beam epitaxy 分子束外延molecular beam magnetic resonance 分子束磁共振molecular beam maser 分子束微波激射器molecular beam scattering 分子束散射molecular beam spectroscopy 分子束光谱学molecular biology 分子生物学molecular bond 分子键molecular chaos 分子混沌态molecular clock 分子钟molecular cloud 分子云molecular compound 分子化合物molecular conductivity 分子导电率molecular crystal 分子晶体molecular diffusion 分子扩散molecular dynamics 分子动力学molecular electronics 分子电子学molecular field 分子场molecular field approximation 分子场近似molecular flow 分子流molecular force 分子力molecular force field 分子力场molecular gas laser 分子气体激光器molecular heat 分子热molecular image 分子图象molecular integral 分子积分molecular inversion 分子倒转molecular ion 分子离子molecular kinetic theory 分子运动论molecular lattice 分子晶格molecular magnet 分子磁铁molecular mass 分子质量molecular motion 分子运动molecular orbital 分子轨函数molecular physics 分子物理学molecular polarizability 分子极化度molecular polarization 分子极化molecular pump 分子泵molecular radius 分子半径molecular rays 分子束molecular reaction 分子反应molecular refraction 分子折射molecular rotation 分子转动molecular scattering 分子散射molecular science 分子科学molecular sieve 分子筛molecular structure 分子结构molecular structure theory 分子结构论molecular viscosity 分子粘性molecular volume 克分子体积molecular weight 分子量molecule 分子moletron 分子加速器molten high polymer 熔融高聚物molybdenum 钼moment 矩moment of couple 力偶矩moment of force 力矩moment of impulse 冲量矩moment of inertia 转动惯量moment of momentum 角动量momentum 动量momentum space 动量空间momentum transfer 动量转移momentum transfer cross section 动量转移截面momentum transfer theory 动量转移理论monaural audition 单耳听力monitor 监测器监视器monoatomic gas 单原子气体monoatomic layer 单原子层monoceros 座monochord 弦音计monochromat 单色透镜monochromatic aberration 单色象差monochromatic light 单色光monochromatic radiation 单色辐射monochromatic rays 单色射线monochromaticity 单色性monochromatization of neutron 中子的单色化monochromatization of x rays x 射线单色化monochromator 单色器单色光镜monoclinic system 单斜晶系monocrystal 单晶monocular 单筒望远镜monodispersive system 单分散系monolithic circuit 单片电路monomer 单体monomode laser 单模激光器monomolecular film 单分子膜monopole 单极monopole moment 单极子矩monopole transition 单极跃迁monostable multivibrator 单稳多谐振荡器monotectic 偏晶体monte carlo method 蒙特卡罗法month 月moon 月球moon power station 月球发电站moon's age 月龄morning star 晨星morphophysics 形态物理学morse potential curve 莫尔斯势能曲线mos diode mos 二极管mos field effect transistor mos 金属氧化物半导体场效应晶体管mos integrated circuit mos 集成电路mos structure mos 结构mosaic crystal 嵌镶晶体mosaic structure 嵌镶结构moseley's law 莫塞莱定律mosfet mos 金属氧化物半导体场效应晶体管motion 运动motion equation 运动方程motor 电动机mott insulator 莫脱绝缘体mott scattering 莫脱散射mott transition 莫脱跃迁mottelson valatin effect 莫特尔逊瓦拉廷效应movement of the pole 极运动movement stability 运动的稳定性moving cluster 移动星团moving coil galvanometer 动圈检疗moving iron vane instrument 动叶式仪表moving magnet galvanometer 动磁型电疗moving magnet instrument 动磁式仪表moving medium acoustics 运动介质声学moving striation 活动条纹mpd arc mpd 弧光mtller scattering 摩利尔散射mts system of units mts单位制mu factor 放大系数multi color photometry 多色测光multi crystal x ray spectrometer 多晶x 射线光谱仪multi function observer 多功能观测器multichannel interferometric spectrometer 多道干涉光谱仪multichannel pulse height analyzer 多道脉冲高度分析器multienzymatic reaction 多酶反应multifilament composite wire 多丝结构复合线multigroup model 多群模型multilayer film 多层胶片multilayer mirror 多层反射镜multimode laser 多模激光器multimolecular layer 多分子层multiparticle correlation 多粒子关联multiparticle production 多粒子产生multiphase flow 多相流multiphoton absorption 多光子吸收multiphoton dissociation 多光子离解multiphoton process 多光子过程multiphoton transition 多光子跃迁multiple beam interference 多光束干涉multiple beam interferometry 多光束干涉测量法multiple collision 多次碰撞multiple correlation 多重相关multiple coulomb scattering 多次库仑散射multiple electrode tube 多栅管multiple electrode valve 多栅管multiple excitation 多次激发multiple galaxy 多重星系multiple ionization 多次电离multiple mirror telescope 多镜望远镜multiple periodic motion 多周期运动multiple process 多重过程multiple production 多重产生multiple reflection 多次反射multiple refraction 多次折射multiple scattering 多次散射multiple star 聚星multiple structure 多重结构multiplet 多重线multiplet term 多重项multiplication 增殖multiplication factor 倍增系数multiplicity 多重性multiplier 倍增器multiply connected region 多连通域multiply periodic motion 多重周期运动multiply twinned particle 多重孪晶粒子multiplying factor 倍率multipole 多极multipole expansion 多极展开multipole moment 多极矩multipole radiation 多极辐射multipurpose minicamera 多功能缩微照相机multipurpose reactor 多用堆multislit spectrometry 多狭缝能谱测定法multispectral photography 多谱照像术multispectral satellite data 多谱卫星数据multitarget tracking 多目标跟踪multivariate analysis 多变量分析multivibrator 多谐振荡器multiwire chamber 多丝室multiwire counter 多丝计数管mumeson 介子muon 介子muon beam 子束muon capture 子俘获muon catalyzed fusion 子催化聚变muon neutrino 子中微子muon number 子数muon spin rotation 子自旋转动muonic atom 原子muonic catalysis 子催化muonium 子偶素murchison meteorite 默基森陨星musca 苍蝇座musical acoustics 音乐声学musical scale 音阶musical sound 乐音muspace 空间mutarotation 变旋mutation 突变mutual conductance 互导mutual inductance 互感mutual induction 互感应mutual neutralization 互中性化myopia 近视myria 万myriad 一万myriads 无数myriameter 万米myriametric wave 超长波。

一种基于Chimera软件的分子动力学模拟方法

2021.13科学技术创新一种基于Chimera 软件的分子动力学模拟方法马学婧*李俊甫宋立立张兆英王悦孙琳琳（沧州师范学院生命科学学院，河北沧州061001）Chimera 由美国加州大学旧金山分校的生物计算可视化和信息学中心开发，并得到了美国国立卫生研究院的部分支持[1]。

作为一个可高度延伸的程序，它可应用于密度图、超分子组装、序列比对、对接结果、轨迹和构象集合，也可以生成高质量图像和动画[2-4]。

Chimera 的官方网站(/chimera/)上可以查阅快速入门、用户手册、命令行索引和一些教程与视频，还可以观赏用该软件制作的图片和动画。

在下载页面，它还提供了Windows ，Mac 和Linux 三个版本供学术、政府和非营利机构和个人使用者免费下载使用。

Chimera 功能强大，界面友好，可帮助没有编程基础的教师和科研人员利用其提供的多种模块化工具进行简单的分子动力学模拟，并且可用于多种操作系统，无需购买昂贵的服务器也可以满足基本的分析需求。

因此，本文将对基于Chimera 软件的分子动力学模拟方法进行阐述。

1蛋白质结构准备1.1蛋白质结构可视化首先打开一个已经下载的蛋白质结构文件（后缀为.PDB ）或选择Fetch by ID ，输入蛋白质结构的ID 调入蛋白质结构文件。

在Presets 中根据需要选择展示模式。

在Select 中，Chain 选项可以选择蛋白质复合物不同的链；Chemistry 选项可以根据化学性质，如元素、功能基团和原子轨道对蛋白质进行选择；Residue 选项可以对20种标准氨基酸进行选择，也可以按照性质对某一类氨基酸进行选择；Structure 选项可以对蛋白质的骨架、离子、配体、核酸和特定的二级结构等进行选择。

选择完毕后，可应用Actions 中的工具对选定的对象进行编辑，如：Atoms/Bonds 选项可以隐藏或显示原子或键，设置显示模式为棍型、球棍型等；Ribbon 选项可以隐藏或显示蛋白质的某一部分，还可以改变带状模式的类型；Surface 选项可以隐藏或显示蛋白质的表面，并设置显示模式和透明度；Color 选项可以对选中的对象进行上色；Label 选项可以对原子、氨基酸残基进行标注，且可自主选择标注的格式。

固态离子导体新突破 ceder组面心立方氧化物超快锂离子传导-概述说明以及解释

固态离子导体新突破ceder组面心立方氧化物超快锂离子传导-概述说明以及解释1.引言1.1 概述固态离子导体是一种具有高离子迁移率和稳定性的材料，可以作为高性能电池和传感器的关键组件。

近年来，人们对固态离子导体的研究越来越深入，推动了纳米科技和电子技术的发展。

Ceder组面心立方氧化物作为一类新型固态离子导体材料，引发了广泛的研究兴趣。

与传统的液态电解质相比，Ceder组面心立方氧化物具有更高的离子传导率和较好的化学稳定性。

这使得固态离子导体的应用更加广泛，可用于高能量密度的锂离子电池、固态电解质超级电容器以及化学传感器等领域。

本文将重点介绍Ceder组面心立方氧化物在超快锂离子传导方面的研究进展和机制。

通过深入分析材料的结构特点和离子传导机制，探索实现高效能量转换和存储的新途径。

同时，对固态离子导体新突破的意义和Ceder组面心立方氧化物在锂离子传导方面的应用前景进行了综述和展望。

通过本文的研究，我们可以更好地理解固态离子导体的性能和应用前景，为高效能源转换和储存技术的发展提供有力支持。

同时，这对于推动新型材料的创新和应用具有重要的科学和实践价值。

1.2文章结构文章结构部分的内容可以描述文章的主要组成部分和每个部分的内容概要。

下面是参考内容：2. 正文2.1 固态离子导体的定义和意义在本节中，将介绍固态离子导体的概念和其在能源领域中的重要性。

将阐述固态离子导体相对于传统液态电解质的优势，并且探讨其应用于锂离子电池、固态超级电容器等领域的前景。

2.2 Ceder组面心立方氧化物的特点本节将探讨Ceder组面心立方氧化物在固态离子导体领域的独特特点。

将介绍该氧化物的晶体结构、较高的离子导电性以及优异的化学稳定性，并且讨论这些特点如何促进其在锂离子传导方面的应用。

2.3 超快锂离子传导的机制本节将深入研究Ceder组面心立方氧化物中超快锂离子传导的机制。

将介绍其中的离子扩散与空位迁移机制、晶体结构调控对离子传导性能的影响等内容。

细胞器之间相互作用在非酒精性脂肪性肝病发生发展中的作用

2 ＤＯＩ：１０．３９６９／ｊ．ｉｓｓｎ．１００１－５２５６．２０２３．０１．０２８细胞器之间相互作用在非酒精性脂肪性肝病发生发展中的作用刘天会首都医科大学附属北京友谊医院肝病中心，北京１０００５０通信作者：刘天会，ｌｉｕ＿ｔｉａｎｈｕｉ＠１６３．ｃｏｍ（ＯＲＣＩＤ：００００－０００１－６７８９－３０１６）摘要：细胞器除了具有各自特定的功能外，还可与其他细胞器相互作用完成重要的生理功能。

细胞器之间相互作用的异常与疾病的发生发展密切相关。

近年来，细胞器之间相互作用在非酒精性脂肪性肝病（ＮＡＦＬＤ）发生发展中的作用受到关注，特别是线粒体、脂滴与其他细胞器之间的相互作用。

关键词：非酒精性脂肪性肝病；细胞器；线粒体；脂肪滴基金项目：国家自然科学基金面上项目（８２０７０６１８）ＲｏｌｅｏｆｏｒｇａｎｅｌｌｅｉｎｔｅｒａｃｔｉｏｎｉｎｔｈｅｄｅｖｅｌｏｐｍｅｎｔａｎｄｐｒｏｇｒｅｓｓｉｏｎｏｆｎｏｎａｌｃｏｈｏｌｉｃｆａｔｔｙｌｉｖｅｒｄｉｓｅａｓｅＬＩＵＴｉａｎｈｕｉ．（ＬｉｖｅｒＲｅｓｅａｒｃｈＣｅｎｔｅｒ，ＢｅｉｊｉｎｇＦｒｉｅｎｄｓｈｉｐＨｏｓｐｉｔａｌ，ＣａｐｉｔａｌＭｅｄｉｃａｌＵｎｉｖｅｒｓｉｔｙ，Ｂｅｉｊｉｎｇ１０００５０，Ｃｈｉｎａ）Ｃｏｒｒｅｓｐｏｎｄｉｎｇａｕｔｈｏｒ：ＬＩＵＴｉａｎｈｕｉ，ｌｉｕ＿ｔｉａｎｈｕｉ＠１６３．ｃｏｍ（ＯＲＣＩＤ：００００－０００１－６７８９－３０１６）Ａｂｓｔｒａｃｔ：Ｉｎａｄｄｉｔｉｏｎｔｏｉｔｓｏｗｎｓｐｅｃｉｆｉｃｆｕｎｃｔｉｏｎｓ，ａｎｏｒｇａｎｅｌｌｅｃａｎａｌｓｏｉｎｔｅｒａｃｔｗｉｔｈｏｔｈｅｒｏｒｇａｎｅｌｌｅｓｔｏｃｏｍｐｌｅｔｅｉｍｐｏｒｔａｎｔｐｈｙｓｉｏｌｏｇｉｃａｌｆｕｎｃｔｉｏｎｓ．Ｔｈｅｄｉｓｏｒｄｅｒｓｏｆｏｒｇａｎｅｌｌｅｉｎｔｅｒａｃｔｉｏｎｓａｒｅｃｌｏｓｅｌｙａｓｓｏｃｉａｔｅｄｔｈｅｄｅｖｅｌｏｐｍｅｎｔａｎｄｐｒｏｇｒｅｓｓｉｏｎｏｆｖａｒｉｏｕｓｄｉｓｅａｓｅｓ．Ｉｎｒｅｃｅｎｔｙｅａｒｓ，ｔｈｅｒｏｌｅｏｆｏｒｇａｎｅｌｌｅｉｎｔｅｒａｃｔｉｏｎｓｈａｓａｔｔｒａｃｔｅｄｍｏｒｅａｔｔｅｎｔｉｏｎｉｎｔｈｅｐｒｏｇｒｅｓｓｉｏｎｏｆｎｏｎａｌｃｏｈｏｌｉｃｆａｔｔｙｌｉｖｅｒｄｉｓｅａｓｅ，ｅｓｐｅｃｉａｌｌｙｔｈｅｉｎｔｅｒａｃｔｉｏｎｓｂｅｔｗｅｅｎｍｉｔｏｃｈｏｎｄｒｉａ，ｌｉｐｉｄｄｒｏｐｌｅｔｓ，ａｎｄｏｔｈｅｒｏｒｇａｎｅｌｌｅｓ．Ｋｅｙｗｏｒｄｓ：Ｎｏｎ－ａｌｃｏｈｏｌｉｃＦａｔｔｙＬｉｖｅｒＤｉｓｅａｓｅ；Ｏｒｇａｎｅｌｌｅｓ；Ｍｉｔｏｃｈｏｎｄｒｉａ；ＬｉｐｉｄＤｒｏｐｌｅｔｓＲｅｓｅａｒｃｈｆｕｎｄｉｎｇ：ＮａｔｉｏｎａｌＮａｔｕｒａｌＳｃｉｅｎｃｅＦｏｕｎｄａｔｉｏｎｏｆＣｈｉｎａ（８２０７０６１８）细胞器可以通过膜接触位点与其他细胞器相互作用，完成物质与信息的交换，形成互作网络［１］。

定量电子显微学方法与氧化钛纳米结构研究获国家自然科学二等奖

据介绍，包括美国、Ｈ本、欧盟、俄罗斯在内的５０多拓宽，释许多传统理论无法描述的物质体系，且将理论解并
个国家和地区都有各自明确的纳米科技发展战略，投入巨成果成功应用到纳米结构的研究领域。在科学家眼中，食盐不是食盐，而是一种典型的离子资、抢占战略制高点。美国国家纳米讨‘ （划ＮＮＩ）２１０１晶体。么一种最最普通的东西，电子显微镜去观察它的这用年财政预算ｌ美元，历年投入稳定增长。日本尤其重视８亿结构时，也没有好的理论去描述电子在这种离子晶体表面纳米技术在信息、金属、环境、能源、生命科学以及基础技的衍射现象。彭练矛团队给出了描述诸如离子晶体表面衍
仿生智能纳米界面材料、碳纳米管宏观薄膜及纤维结构的贝尔物理学奖就颁发给了成功地分离出单层石墨烯材料的
制备与性能研究、纳米结构金属材料达到高性能极限等诸两名英国物理学家。
多方面取得突破。
像科技研发和产业化的整体协调。同时，入并持续开展纳米重，多数情况下我们在电子显微镜中所看到的 ‘ ’不能直深接反映物体的真正结构。练矛说，用量子力学的原理， ”彭利科技领域战略研究，提高决策能力；整合资源，形成在纳米

单原子催化剂在电化学非酶葡萄糖传感应用研究

单原子催化剂在电化学非酶葡萄糖传感应用研究下载提示：该文档是本店铺精心编制而成的，希望大家下载后，能够帮助大家解决实际问题。

文档下载后可定制修改，请根据实际需要进行调整和使用，谢谢！本店铺为大家提供各种类型的实用资料，如教育随笔、日记赏析、句子摘抄、古诗大全、经典美文、话题作文、工作总结、词语解析、文案摘录、其他资料等等，想了解不同资料格式和写法，敬请关注！Download tips: This document is carefully compiled by this editor. I hope that after you download it, it can help you solve practical problems. The document can be customized and modified after downloading, please adjust and use it according to actual needs, thank you! In addition, this shop provides you with various types of practical materials, such as educational essays, diary appreciation, sentence excerpts, ancient poems, classic articles, topic composition, work summary, word parsing, copy excerpts, other materials and so on, want to know different data formats and writing methods, please pay attention!单原子催化剂在电化学非酶葡萄糖传感应用研究1. 引言在现代传感器技术的发展中，电化学传感器因其高灵敏度、快速响应和低成本而备受关注。

V-型三能级原子与双模腔场共振相互作用时原子纠缠特性的研究(英文)

V-型三能级原子与双模腔场共振相互作用时原子纠缠特性的
研究(英文)
胡明亮;田东平;柳海
【期刊名称】《量子光学学报》
【年(卷),期】2007(13)2
【摘要】提出了一种利用V—型三能级原子与双模腔场的共振相互作用制备多原子及多腔场纠缠W态的新方案。

【总页数】6页(P92-97)
【关键词】V-型三能级原子;双模腔场;纠缠W态;共生纠缠;热纠缠
【作者】胡明亮;田东平;柳海
【作者单位】西安交通大学理学院;西安邮电学院
【正文语种】中文
【中图分类】O431
【相关文献】
1.利用双模腔场与V型三能级原子共振作用隐形传送腔场纠缠态 [J], 卢道明
2.利用V-型三能级原子与双模腔场的共振相互作用制备纠缠W态 [J], 胡明亮;田东平;柳海
3.V-型三能级原子与双模腔场模型中的纠缠交换方案 [J], 张蕾;杨洁
4.利用Ξ型三能级原子与腔场的非共振相互作用制备原子纠缠态 [J], 林秀;李洪才
5.纠缠Ⅴ-型三能级原子与纠缠双模腔场相互作用的纠缠特性 [J], 张蕾;强稳朝;郝丹辉
因版权原因，仅展示原文概要，查看原文内容请购买。

新型电子皮肤实现各尺度人体活动检测

姻傅昭仪【摘要】电子皮肤是一种与人体皮肤具有相容性的电子设备，近日，中国科研团队在电子皮肤领域取得新突破，他们提出了一种一体式自供能全透明柔性电子皮肤，改变了传统电子皮肤穿戴不方便、不美观的缺点，并实现了对人体微弱生理信号和大范围肢体运动在内的多尺度人体活动的检测。

【关键词】电子皮肤；新突破；应用前景新型电子皮肤实现各尺度人体活动检测当今社会，可穿戴智能设备已经普及开来，智能眼镜、智能手表、智能腕带等已经被大众所熟知。

电子皮肤是一种与人体皮肤具有相容性的电子设备，它可以“穿”在身上，模仿人类皮肤感知功能，感受外界刺激，并且把这些刺激转化成不同的输出信号。

电子皮肤被认为是实现无创人机交互和可穿戴设备的理想电子设备，在智慧医疗领域能发挥很大的作用。

电子皮肤主要是由三部分元件构成：传感器、信号转换与传输电路、具有特殊蛋白的神经细胞。

理想的柔性电子皮肤应该是其所有组成部件具有可拉伸性、透明性且高度集成，有独立稳定可靠的能源供应组件以及无线信息传输功能。

传统电子皮肤通常依靠笨重的刚性电池或能量收集装置来运行，前者机械刚性大、重量大、体积大，后者受位置、机体或环境机械活动水平等特殊条件的限制，不能提供持续稳定的能源供给。

此外，除了传感部分外，传统电子皮肤大多组件都是刚性的，极大地影响了美感、舒适性和安全性，也对信号采集产生了不利影响。

且目前大多数电子皮肤多为不透明或部分透明，这主要是受限于结构设计、材料选择和渗流理论。

因此，迫切需要开发和构建一款轻薄、柔软、高透明度和高稳定性的一体化自供电透明电子皮肤。

近日，兰州大学物理科学与技术学院兰伟教授领衔的柔性电子科研团队在电子皮肤领域取得新突破。

团队提出了一种一体式自供能全透明柔性电子皮肤，改变了先前穿戴不方便、不美观的缺点。

兰伟教授介绍，该系统由透明超级电容器、可拉伸透明应变传感器和蛇形电阻组成。

由一维银纳米线和二维MXene纳米片构建的“岛桥结构”应变传感器具有极高的灵敏度，超级电容器作为“隐身”电源可为一体式电子皮肤系统进行供电。

高通量分子动力学模拟在药物分子设计中的应用

高通量分子动力学模拟在药物分子设计中的应用随着药物化学的发展，药物分子的设计成为了药物研究领域的重要方向之一。

而分子动力学模拟技术，作为分子计算中的一种主要方法，可以探究分子体系中复杂的结构、动态和相互作用。

这种基于原子级的分子模拟技术被广泛应用于药物分子的设计和研发，特别是在高通量筛选中的应用更是日益突出和重要。

一、高通量分子动力学模拟简介高通量分子动力学模拟技术是实验室筛选药物分子的一种计算方法。

它运用基于牛顿力学的分子动力学理论，对药物分子的物理和化学性质进行模拟。

通过引入随机力和温度因素，模拟分子在三维空间中的运动，得出分子的动力学性能参数，诸如稳定性、亲水性、亲油性、活性位点等，进而指导药物分子结构的设计和构建。

分子动力学模拟技术广泛运用于药物分子的研究，是药物研究领域的重要组成部分。

通过分子动力学模拟，可以获得药物分子构象及结合状态的信息，优化药物分子的稳定性、亲合性和药效等性质。

同时，这项技术也可以预测分子的动力学行为，为后续药物分子的细胞及动物实验提供可参考的理论依据。

二、分子动力学模拟在药物分子设计中的应用2.1 研究药物分子的结构、特性和动态行为分子动力学模拟广泛应用于药物分子的结构、特性和动态行为的研究。

它可以提供关于药物分子的构象结构和稳定性等信息。

如今，分子动力学模拟技术的发展越来越复杂和精细，利用这些模型，可以模拟药物分子在溶液中的运动状态，揭示其与溶剂分子的相互作用。

此外，这种基于分子层面的理论研究将使我们更好地理解药物分子与细胞和体内过程之间的作用机制。

2.2 大规模的高通量筛选药物研究领域中的高通量技术的引入，改变了传统的药物筛选方式，提高了研究效率。

基于分子动力学模拟的高通量筛选技术，旨在通过计算和预测的方式，指导药物分子的设计和优化。

这种筛选技术可以同时对数百万个原子进行模拟，从而显著提高筛选速度和效率，较准确地预测药物分子的活性和亲和性属性。

通过这种技术，研究人员可以更快速地筛选出具有潜在药物效果的物质，实现高效、快捷和准确的药物分子筛选。

分子动力学加电场;lammps

分子动力学加电场；lammpsEnglish Response:Introduction.Molecular dynamics simulations with applied electric fields are widely used to investigate the behavior of charged materials, such as ions in electrolyte solutions or proteins in biological systems. LAMMPS (Large-scaleAtomic/Molecular Massively Parallel Simulator) is a popular molecular dynamics simulation package that offers a versatile platform for performing simulations with applied electric fields.Setting up the Simulation.To set up a molecular dynamics simulation with an applied electric field in LAMMPS, several key steps are involved:1. Define the System: The first step is to define the simulation system, including the molecular structure, atomic charges, and simulation box.2. Create the Input Script: An input script is created to specify the simulation parameters, such as the force field, timestep, and simulation length.3. Apply the Electric Field: An electric field is applied to the system using the "fix efield" command. This command specifies the magnitude and direction of the electric field.4. Run the Simulation: The simulation is run using the "run" command.Analysis of Results.Once the simulation is complete, the results can be analyzed to understand the effect of the electric field on the system. Some common analysis methods include:1. Particle Trajectories: The trajectories ofindividual particles can be tracked to observe their motion under the influence of the electric field.2. Radial Distribution Functions: Radial distribution functions can be calculated to analyze the distribution of particles around a central particle.3. Electric Potential: The electric potential distribution within the simulation box can be computed to visualize the effect of the electric field on the system.Example Input Script.Below is an example input script for a molecular dynamics simulation with an applied electric field in LAMMPS:units real.atom_style full.read_data mmps.fix efield all efield 0.0 0.0 1.0 1.0e5 v_global #Apply electric field along z-axis with magnitude 1e5 V/m.run 100000。

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A reactive molecular dynamics simulation of the silica-water interfaceJoseph C.Fogarty,1,a͒Hasan Metin Aktulga,2Ananth Y.Grama,2Adri C.T.van Duin,3and Sagar A.Pandit1,b͒1Department of Physics,University of South Florida,Tampa,Florida33620-9951,USA2Department of Computer Science,Purdue University,West Lafayette,Indiana47907-2107,USA3Department of Mechanical and Nuclear Engineering,Pennsylvania State University,University Park,Pennsylvania16802-1414,USA͑Received8January2010;accepted31March2010;published online4May2010͒We report our study of a silica-water interface using reactive molecular dynamics.Thisﬁrst-of-its-kind simulation achieves length and time scales required to investigate the detailedchemistry of the system.Our molecular dynamics approach is based on the ReaxFF forceﬁeld ofvan Duin et al.͓J.Phys.Chem.A107,3803͑2003͔͒.The speciﬁc ReaxFF implementation͑SERIALREAX͒and forceﬁelds areﬁrst validated on structural properties of pure silica and watersystems.Chemical reactions between reactive water and dangling bonds on a freshly cut silicasurface are analyzed by studying changing chemical composition at the interface.In our simulations,reactions involving silanol groups reach chemical equilibrium inϳ250ps.It is observed that watermolecules penetrate a silicaﬁlm through a proton-transfer process we call“hydrogen hopping,”which is similar to the Grotthuss mechanism.In this process,hydrogen atoms pass through theﬁlmby associating and dissociating with oxygen atoms within bulk silica,as opposed to diffusion ofintact water molecules.The effective diffusion constant for this process,taken to be that of hydrogenatoms within silica,is calculated to be1.68ϫ10−6cm2/s.Polarization of water molecules inproximity of the silica surface is also observed.The subsequent alignment of dipoles leads to anelectric potential difference ofϳ10.5V between the silica slab and water.©2010AmericanInstitute of Physics.͓doi:10.1063/1.3407433͔I.INTRODUCTIONAmorphous silica͑a-SiO2͒,its surface properties,and hydrolysis have been topics of research in diverse applica-tion domains ranging from geosciences to nanoelectronics. The high dielectric constant and selectivity for chemical modiﬁcation make silica among the most widely used sub-strates in the design of nanoelectronic devices.Recent ad-vances in molecular biology have demonstrated its use in devices capable of performing in vivo screening of biomol-ecules and biomolecular processes,along with other applica-tions in biotechnology that rely on surface modiﬁcation of silica.Silica can serve as a substrate for biosensors,elec-tronic components,and enzymes.1,2Since these devices are often required to function in inhospitable aqueous cellular environments,a detailed understanding of their interactions with water is crucial.Experimental methods such as infrared spectroscopy,3–5 x-ray crystallography,6,7nuclear magnetic resonance,8and electron microscopy do not sufﬁciently describe the pro-cesses by which silica is corroded by water at an atomic scale.9Molecular dynamics͑MD͒techniques,due to their ability to probe nanoscale spatiotemporal processes,can pro-vide valuable insights into this problem.Conventional clas-sical MD has the ability to simulate bulk properties of a-SiO2.10–13It lacks,however,the ability to model chemical reactions,speciﬁcally the dissociation of water and the re-sulting recombination of O and OH units with the silica sur-face.Consequently,while conventional MD simulations can yield reliable data on bulk silica,they do not sufﬁciently describe interfacial properties of interest.10In a signiﬁcant effort,Garofalini et al.simulated water-silica interaction us-ing MD with a dissociative water model.14In this paper,we put forth several new observations using a more general re-active potential that incorporates variable charges as well as conﬁrm a number of observations of Garofalini et al.A re-active potential allows changes in bond order,which coin-cide with changes in electron densities,thereby implying modiﬁcation of partial charges.The current work also ex-tends the scale of reactive simulations.Quantum mechanical ab initio methods have been used to simulate chemical reactions at the silica-water interface.10,15These simulations are typically limited to sub-nanometer length and picosecond time scales.For this rea-son,ab initio approaches are unable to simultaneously de-scribe bulk systems and interfaces.Due to limitations on scalability,surface characteristics of silica in ab initio simu-lations are artiﬁcially constructed,as opposed to being de-rived from an annealing process.16These ab initio simula-tions generally also ignore the interaction of the interfacial section with the silica bulk.Attempts have been made to bridge this gap using hybrid simulation techniques,whereby the surface sites are simulated using quantum calculations and bulk sections are simulated using classical MD.17This approach has potential drawbacks due to the interface be-tween the ab initio and MD regions of the system.Classicala͒Electronic mail:jcfogart@.b͒Electronic mail:pandit@.THE JOURNAL OF CHEMICAL PHYSICS132,174704͑2010͒0021-9606/2010/132͑17͒/174704/10/$30.00©2010American Institute of Physics132,174704-1forceﬁelds must be tuned not only toﬁt experimental results but also to interface with the ab initio calculations.Inconsis-tencies between MD forceﬁelds and quantum calculations can result in unwanted changes in the structure of the system.15In this work,we use a novel MD forceﬁeld,ReaxFF, developed by van Duin et al.18This method relies on the development of empirical forceﬁelds that mimic the quan-tum mechanical variation of bond order.ReaxFF replaces the harmonic bonds of conventional MD with bond orders and energies that depend on interatomic distances.Valencies,ex-plicitly satisﬁed in MD simulation,necessitate many-body calculations in ReaxFF.The approach allows bond order and all bonded interactions to decay smoothly to zero,allowing chemical reactions within a MD framework.Consequently, ReaxFF can overcome many of the limitations inherent to nonreactive MD while retaining,in large part,the desirable scalability.The applicability of ReaxFF to large scale silica systems has been questioned on the basis of its computa-tional cost.19State-of-the-art implementations͑SERIALREAX͒, however,have demonstrated excellent computational efﬁ-ciencies,thereby greatly alleviating scalability concerns.In this paper,we present the results of a reactive MD simulation of a water-silica system.We show that ReaxFF is able to reproduce bulk properties of silica and water to a high degree of accuracy,silica surface properties in agreement with that of ab initio calculations,and predict chemical re-actions at the interface.To the best of our knowledge,no other computational approach satisfactorily addresses all three aspects of this problem simultaneously.II.METHODSAll of the MD simulations in the paper are performed using SERIALREAX molecular simulation software version 2.0.0.20ReaxFF differs from a classical MD approach in sev-eral fundamental ways.•Although no statistical mechanical approach would ever formally assume distinguishability,indistinguishability is completely required in the analysis of reactive simu-lations.ReaxFF allows atoms to move from one chemi-cal species to another.Consequently,interpretation of ReaxFF data must assume the indistinguishability of particles,inherent to any quantum mechanical system, even though the assumption is not explicit in the simu-lation technique itself.Speciﬁcally,for our system,oxy-gen atoms may transition between water and silica and hence cannot be labeled as members of speciﬁc chemi-cal species.•The bond order term and its corrections force the Re-axFF potential to be inherently many-body.Conse-quently,all forceﬁeld terms dependent on bond order become many-body interactions.This makes the calcu-lation of a reactive potential more computationally ex-pensive than a classical MD approach.•The SERIALREAX model incorporates a charge equilibra-tion technique͑QEq͒introduced by Rappéand Goddard.21This approach seeks to minimize electro-static energy by assigning partial charges based on ion-ization potential,electron afﬁnities,and atomic radii.The total electrostatic energy and atomic chemical po-tential are given byE Q͑Q1...Q N͒=͚A͑E A0+␹A0Q A͒+1/2͚A,B Q A Q B J AB,͑1͒␹A͑Q1...Q N͒=␹A0+J AA0Q A+͚B A J AB Q B.͑2͒Total energy is then minimized with the constraints that total charge remains constant and that all atomic chemi-cal potentials remain equal.Implementation of QEq re-quires the solution of a large system of linear equations with constraints.In SERIALREAX,this large system of equations is solved at every step using an efﬁcient pre-conditioned linear solver͓GMRES͑Ref.22͔͒.•Reordering of chemical species within ReaxFF requires dynamic neighbor lists,even for bonded interactions, such as bond,angle,and torsion.This requires careful design and orchestration of dynamic data structures within SERIALREAX to minimize computational over-head with regard to classical MD.These differences add signiﬁcant complexity to ReaxFF implementations when compared to a classical MD ap-proach.SERIALREAX relies on a range of sophisticated algo-rithms,data structures,and numerical techniques to mini-mize the cost of these computations.As a result,ReaxFF retains much of desirable scalability of classical MD but adds considerable simulation power.A.System preparation1.Preparation of a-SiO2systemSince ReaxFF updates bond order and bond order depen-dent quantities at every time-step,it requires a smaller time-step than conventional MD approaches.23Chemical reactions occur over subpicosecond time scales.Thus,all simulations were performed with a0.5fs time-step.All simulations, unless otherwise noted,were performed at a temperature of 300K.A Nosé–Hoover thermostat was used in each case to couple the system to a heat reservoir.24Whenever a constant pressure and temperature͑NPT͒ensemble was utilized,a Berendsen barostat and thermostat were used to couple to a bath.25,26A Berendsen barostat was preferred over a Parrinello–Rahman barostat to avoid large pressureﬂuctua-tions,which can lead to unrealistic chemical reactions.The amorphous silica system was constructed by ini-tially placing2000silica͑SiO2͒molecules randomly in a 67.4ϫ67.4ϫ20.0Å3box,resulting in a silica system with an initial density of2.2g/cm3.To eliminate atomic overlaps and bad contacts,the system was energy-minimized in a mi-crocanonical͑NVE͒ensemble for50ps.The bulk and sur-face properties of a silica system are highly dependent on the annealing procedure.27Simulation of an amorphous silica slab with the correct structural properties requires very high temperature annealing.28Hence,the system was annealed174704-2Fogarty et al.J.Chem.Phys.132,174704͑2010͒twice from 4000to 300K.In the ﬁrst annealing simulation,the system was heated to 4000K and gradually cooled to 300K with steps of 100K per 4ps using NVT ensemble.The system was again heated to 4000K using an NPT ensemble for ϳ75ps until the system completely melted and formed a uniform block with dimensions of 52.110ϫ50.174ϫ36.477Å3.The system was again cooled,still in an NPT ensemble,to 300K in steps of 100K per 4ps.All NPT simulations were conducted at a constant pressure of 1atm.The ﬁnal annealed system was used to perform a continuous simulation of 185ps for validation of silica properties.The same system was also used for the silica-water interface simulation.Figure 1shows a freshly cut surface of annealed silica.2.Preparation of pure water systemThe water system was prepared by ﬁlling a box of size 51.800ϫ49.900ϫ23.600Å3͑chosen to ﬁt the silica sys-tem ͒with 2025water molecules.This resulted in a density of 0.99g /cm 3.Water molecules were added with random alignment and location ͑avoiding overlap ͒.The system was then thermalized under an NVT ensemble for 664ps.A NPT ensemble was not used due to the need to ﬁt the water box to the silica slab.Although semi-isotropic pressure coupling would have allowed for a NPT ensemble,it was not avail-able in the SERIALREAX version used in this work.This sys-tem was used both for the interface simulation and the vali-dation of water properties.Position,bond,and angle data were output every 500steps for water veriﬁcation analysis.3.Preparation of silica-water interfaceThe water and silica systems described above were com-bined by positioning copies of the water system normal to the z-axis and adjacent to the silica system,resulting in total system dimensions of 52.110ϫ50.174ϫ83.700Å3.The system was then simulated under the NVT ensemble.NVT was used instead of NPT because the difference in compress-ibility between a-SiO 2and water would cause unrealisticpressure effects.After 70ps,the simulation was then re-started with velocities randomly generated to ﬁt the set tem-perature.Velocities were reset in order to remove any arti-facts from the system construction.The simulation was then run for a total of 580ps.The system maintained thermal equilibrium with the heat bath for the ﬁnal 150ps.Therefore,these steps were used for structural and electrostatic analysis.As the reactions between water and the silica slab took place in the ﬁrst 150ps of the run,chemical analysis was per-formed on these initial steps.For the ﬁnal 370ps of simula-tion,position,velocity,bond,and angle data were written every 250steps.Figure 2shows a snapshot of the simulated system.B.Force ﬁeld parametersTo obtain a ReaxFF description capable of describing the reactions at the SiO 2/water interface we modiﬁed the ReaxFF Si/O/H parameters described by van Duin et al.30While these parameters could describe Si /SiO 2interfaces,they were solely based on quantum mechanical ͑QM ͒data de-scribing radical reactions and were thus unable to describe the energetics related to proton-transfer reactions at the water/silica interface.To extend ReaxFFSiO ͑2003͒to these reactions,we ﬁrst replaced the O/H parameters with a set of ReaxFF O/H parameters ﬁtted against water-clusters and proton-transfer reactions in H 3O +͓H 2O ͔n and OH −͓H 2O ͔n systems.31Keeping the O/H parameters ﬁxed,we subse-quently reﬁtted the Si/O,Si/Si,and Si/H bond and angle parameters against the QM-based training set data used to ﬁt ReaxFFSiO ͑2003͒.These data included bond dissociation curves for all Si/O/H bond combinations,angle distortion energies for all Si/O/H angle combinations,and equations of state for bulk-Si and bulk-SiO 2-data.To augment this train-ing set for water/silica cases,we added two additional sets of QM-based data ͑at the DFT /B3LYP /6-311G ءء++level of theory ͒to the training set.These sets described ͑i ͒the bind-ing and dissociation of a single water molecule from a Si ͑OH ͒4molecules and ͑ii ͒reaction energies for the Si ͑OH ͒4polymerization.32Figure 3and Table I compare the ReaxFFFIG.1.Surface of annealed silica.Undercoordinated silicon atoms are bound to only three oxygen atoms.Undercoordinated oxygen atoms are bound to only one silicon atom.͓Image generated with QUTEMOL ͑Ref.29͒.͔FIG.2.System snapshot:z-axis shown as horizontal.Oxygen ͑red ͒,hydro-gen ͑white ͒,and silicon ͑yellow ͒atoms shown.͓Image generated with QU-TEMOL ͑Ref.29͒.͔174704-3A reactive silica-water interface J.Chem.Phys.132,174704͑2010͒results to the QM-data for these two cases,indicating that ReaxFF can successfully describe both the nonreactive inter-action of a water molecule with a hydroxylated silica surface and the reaction energies associated with silica formation.III.RESULTSA.Validation of models 1.WaterValidation of the water model involves computation of the average structural properties of a single water molecule and the static and dynamic properties of bulk water.Table II shows a comparison of water properties computed using our model with those of ab initio simulations and experiments.In spite of several approximating assumptions,our model reproduces several key properties of water.The oxygen-hydrogen bond length ͑d OH ͒in the ﬁrst line is the average distance between oxygen and hydrogen atoms that share abond order Ն12.We note that the model reproduces experi-mental data for bond length and angle within the standard deviations.The partial charges ͑lines 3and 4͒on oxygen and hydrogen atoms ͑q O and q H ͒result from the QEq process.These charges ͑please see Fig.4͒are lower than the popular ﬁxed charge water models,such as simple point charge ͑SPC ͒and extended simple point charge ͑SPC/E ͒.Lower charges are expected since ﬁxed charge models rely on a mean ﬁeld approximation of large partial charges to repro-duce bulk properties of liquid water.42Coordinate independence of the dipole moment vector requires molecular charge neutrality.While the QEq method implemented in SERIALREAX software imposes a constant charge constraint on the entire system,it does not requiremolecules to be charge neutral.Hence,computation of the electrical dipole moment of water in ReaxFF is nontrivial.To enforce neutrality,half of the oxygen charge was assigned to each hydrogen atom,ignoring the hydrogen charge computed by QEq.Figure 4shows the distribution of charge on water molecules.The standard deviation of water charge about a neutral molecule is 4.1ϫ10−2e ,which indicates that a sub-stantial number of water molecules are not neutral.However,the distribution suggests that the molecular charge constraint is only marginally violated by the QEq procedure.Conse-quently,approximations involved in computation of dipole moment introduce negligible error.The average dipole mo-ment in a water cluster has been established by both experiment 37and theory 43to be larger than that of an isolated molecule.The dipole moment reported for ab initio simula-tion is for an isolated molecule,while the value presented here is for bulk water.The structure factor describes the scattering interaction between incident particles and the form of the scattering me-dium.Structure factor is not dependent on the nature of the interaction itself but rather on the geometry of the system alone.A Fourier transform on the density function produces the structure factor.44Since the radial distribution function ͑RDF ͒is dependent on the density function,it can be used to predict the results of scattering experiments.The RDF be-tween two atomic species is deﬁned asg ͑r ͒=N ͑r ͒4␲r 2␳␦r,͑3͒where N ͑r ͒is the number of type 2atoms in the shell be-tween r and r +␦r around the type 1atoms and ␳is the number density of type 2atoms,taken as the ratio of the number of atoms to the volume of the simulation cell.Table II ͑rows 8and 9͒lists the properties derived from O–O RDF.The RDF for water is presented in Fig.5.The diffusion coefﬁcient ͑row 10of Table II ͒of oxygen in water is representative of its translational mobility.It can be calculated from the long time behavior of the mean square displacement ͑MSD ͒of the atom using the EinsteinrelationO-Si distance (Å)E n e r g y d i f f e r e n c e (k c a l /m o l )FIG.3.Reax force ﬁeld validation.TABLE I.Water data.ReactionReaxFF QMaSi ͑OH ͒4+Si ͑OH ͒3O −→͑OH ͒3Si–O–Si ͑OH ͒2O −+H 2O ͑dimer anion ͒+H 2OϪ23.0Ϫ20.8͑OH ͒3Si–O–Si ͑OH ͒2O −+Si ͑OH ͒4→͑OH ͒3Si–O–Si ͑OH ͒2–O–Si ͑OH ͒2O −+H 2O ͑trimer anion+H 2O ͒Ϫ18.9Ϫ14.3͑OH ͒3Si–O–Si ͑OH ͒2–O–Si ͑OH ͒2O −+Si ͑OH ͒4→branched quadrimer anion+H 2OϪ24.0Ϫ28.9aReference 32.2468101214161820−0.7362320.36545−101charge(e )Water Charge Distibution Water Oxygen HydrogenFIG.4.Water charge distribution.Water molecule charge is distributed about neutral,with oxygen and hydrogen charges distributed about −0.736e and 0.365e ,respectively.174704-4Fogarty et al.J.Chem.Phys.132,174704͑2010͒D=limt→ϱ͉͗rជ͑t͒−rជ͑t0͉͒2͘6͑t−t0͒,͑4͒where rជis the position of the atom.The MSD of each atom was calculated over166ps intervals in the664ps productionrun.A least-squares straight-lineﬁt of the trajectory averagedMSD was then performed over the subinterval from40to166ps within the166ps interval.Figure6shows the MSDof water oxygen and hydrogen as a function of time.Thediffusion coefﬁcients of these two atomic species do notshow signiﬁcant difference.This indicates that water diffusesin bulk water mostly as entire molecules without dissocia-tion.2.SilicaThe validation of the amorphous silica model involvescomputation of structural properties including mass density,bond lengths,bond angles,and RDFs.Table III reports theseproperties for the simulated model and a comparison with abinitio and experimental values.Though the reported density for silica in ReaxFF islower than that from classical MD and experiments,the spe-ciﬁcs of the annealing process have an effect on the struc-tural properties of theﬁnal system.The silicon-oxygen bondlength͑d SiO͒,calculated as the average distance between bonded silicon and oxygen atoms,is in agreement with bothexperiment and MD.Angles within a tetrahedra͑O–Si–Oangles͒and between two tetrahedra͑Si–O–Si angles͒aregiven,along with full width at half maximum͑in parenthe-ses͒.There is a wide range of Si–O–Si angles from120to180,which is a fundamental difference between crystallinesilica and a-SiO2.6Important aspects of the RDF for a-SiO2are also re-ported in Table III.The maximum values in the RDF͑RDFmax.͒show the most likely distance between the two atomicspecies in a speciﬁc coordination shell.A minimum valueindicates the radius of the shell.The average coordinationnumbers for silicon and oxygen͑Si and O coordination,re-spectively͒,which are determined by counting the number of atoms within theﬁrst coordination shell,reﬂect the high level of coordination in bulk silica.The RDFs are presented in Fig.7.B.Silica-water interfaceReaxFF allows the application of a broad range of ana-lytical techniques.This approach yields information about the change in concentration of chemical species,which oth-erwise would not be available to MD simulation.ReaxFF is capable of probing length and time scales that permit utili-zation of thermodynamic and statistical tools.As a result,the silica-water interface described produces a large amount of information.The data can be interpreted to determine the structural properties of the system,i.e.,system geometry, bond characteristics,and molecular orientations.The scope of this analysis cannot be reached by ab initio calculations. Unlike other classical MD approaches,ReaxFF generates data regarding the chemical composition of the system.Start-ing with pure water and pure silica,we end with a hydroxy-lated silica surface covered by silanol͑Si–OH͒groups.TheTABLE II.Water data.Reax results compared with ab initio,SPC/E,and experimental.Water bond length is given as d OH.RDF minimum and maximum values are local min and max.Diffusion is atomic self-diffusion. Property ReaxFF SPC/E a Ab initio BLYP b Experimentald OH͑Å͒0.98Ϯ0.04 1.0000.9730.957c HOH angle͑°͒104Ϯ4109.47104.4104.5dq O͑e͒−0.73Ϯ0.03Ϫ0.8476¯¯q H͑e͒0.36Ϯ0.030.4238¯¯␮͑D͒ 2.1Ϯ0.2 2.35 1.81 2.9eOO distance͑Å͒ 2.88Ϯ0.2¯ 2.95 2.98fOHO angle͑°͒168Ϯ6¯173174gOO RDFﬁrst max.͑Å͒ 2.77¯ 2.80 2.82hOO RDFﬁrst min.͑Å͒ 3.35¯ 3.35 3.51hD O͑Å2/ps͒0.290.2490.130.24iD H͑Å2/ps͒0.29¯¯¯a Reference33.b Reference34.c Reference35.d Reference36.e Reference37.f Reference38.g Reference39.h Reference40.i Reference41.1020300123456 r(Å2)g(r)Water RDFO−OH−HO−HFIG. 5.Water RDF:RDF between oxygen-oxygen͑O–O͒,hydrogen-hydrogen͑H–H͒,and oxygen-hydrogen͑O–H͒shown for bulk water.174704-5A reactive silica-water interface J.Chem.Phys.132,174704͑2010͒orientation of the water dipole moment gives rise to electric polarization along silica-water surface.This charge distribu-tion gives rise to a measurable potential difference between the water bulk and the silica bulk.ReaxFF facilitates predic-tions for new experimental techniques to investigate this.Since ReaxFF is able to simulate chemical reactions,the approach yields statistically valid samples of reactants pro-duced by the silica-water interface,mostly notably silanol.We are also able to calculate the bond lengths and angles in SiOH units.1.Structural propertiesFigure 8shows the mass density for the interfacial sys-tem as well as its constituent atoms.The system was cut into 0.5Åslabs along the z-axis,and a mass was calculated for each.The large variations seen in the silica bulk result from the lack of ﬂuidity at room temperature in a-SiO 2,which prevents the averaging out of local density extrema.A peakin the total mass density near the surface results from an increase in the oxygen mass density.This local maximum is a result of the strong alignment of water dipole moment with the silica surface.As is clearly illustrated in Fig.8,a sharp boundary between water and silica does not exist.Thus,in order to clearly describe the interfacial area,a Gibbs dividing surface ͑z G ͒was deﬁned on each water-silica interfacial area ͑Fig.9͒.The dividing surface is chosen such that 49͵−ϱz G͑n ͑z ͒−n 1͒dz =−͵z Gϱ͑n ͑z ͒−n 2͒dz ,͑5͒where n is the number density of silicon atoms and the bounds at −ϱand ϱare deﬁned as the points at which n is randomly distributed about n 1or n 2,respectively.Silicon at-oms located outside of these boundaries are deﬁned as being located in the interface,while hydrogen atoms located within these boundaries are deﬁned as being part of the silica bulk.The silica system had a width of 36.5Åbefore the addition of water.An identical analysis was performed using hydro-gen number density,which yielded results that differed by less than 0.5Å.The width of bulk silica,deﬁned as theTABLE III.Silica data.Pure silica in Reax computed with MD and experi-ment.Silicon oxygen bond is given as d SiO .Max and min RDF values are local min and max values.Coordination is calculated as the average number with the ﬁrst coordination shell.Full width at half maximum is given in parentheses.PropertyReaxFF MD Experiment Density ͑g /cm 3͒ 2.14 2.23a2.20bd SiO ͑Å͒1.59Ϯ0.07 1.62Ϯ0.05c1.608Ϯ.004dSi–Si dist.͑Å͒ 3.0Ϯ0.2¯¯O–O dist.͑Å͒ 2.7Ϯ0.3¯ 2.65bSi–O–Si angle ͑°͒150͑21.5͒152͑35.7͒e 144͑38͒,b 153f O–Si–O angle ͑°͒109.2͑20.9͒108.3͑12.8͒e109.4,f 109.5b Si–O RDF ﬁrst max.͑Å͒ 1.56 1.595e 1.608,d 1.620bSi–O RDF ﬁrst min. 2.5¯¯Si–O RDF second max. 3.90 4.12e 4.15bO–O RDF ﬁrst max. 2.53 2.590e 2.626,d 2.65b Si–Si RDF ﬁrst max. 3.06 3.155e 3.077,3.12bSi coordination 3.98¯¯O coordination1.99¯¯aReference 45.b Reference 6.cReference 46.d Reference 47.eReference 27.fReference 48.10203040506070800.10.20.30.40.50.60.7M e a n S q u a r e d D i s p l a c e m e n t (Å2)Time (ps)Mean−Squared Displacement Hydrogen OxygenFIG.6.Water MSD:mean squared displacement shown for oxygen and hydrogen atoms within a pure water system.102030012345678g (r )r (Å2)Bulk Silica RDF O−O Si−Si Si−OFIG.7.Silica RDF:RDFs in pure silica shown for oxygen-oxygen ͑O–O ͒,silicon-silicon ͑Si–Si ͒,and silicon-oxygen ͑Si–O ͒.0.511.522.5301020304050607080ρz (g /c m 3)z(Å)Silica−Water Mass DensitiesOxygen Total Hydrogen SiliconGibbs DividersFIG.8.Mass densities:Mass densities for the interfacial system,illustrating the locations of the Gibbs dividers ͑dashed ͒.Included is density of oxygen ͑red ͒,hydrogen ͑teal ͒,silicon ͑blue ͒,and the total ͑green ͒.174704-6Fogarty et al.J.Chem.Phys.132,174704͑2010͒。