期刊文献+

二次检索

题名
关键词
文摘
作者
第一作者
机构
刊名
分类号
参考文献
作者简介
基金资助
栏目信息

年份

学科

期刊收录

共找到148篇文章
< 1 2 8 >
每页显示 20 50 100
Effects of surface roughness of substrate on properties of Ti/TiN/Zr/ZrN multilayer coatings 被引量:6
1
作者 林松盛 周克崧 +6 位作者 代明江 胡芳 石倩 侯惠君 韦春贝 李福球 佟鑫 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第2期451-456,共6页
Ti/TiN/Zr/ZrN multilayer coatings were deposited on Cr_17Ni_2 steel substrates with different surface roughnesses by vacuum cathodic arc deposition method. Microstructure, micro-hardness, adhesion strength and cross-s... Ti/TiN/Zr/ZrN multilayer coatings were deposited on Cr_17Ni_2 steel substrates with different surface roughnesses by vacuum cathodic arc deposition method. Microstructure, micro-hardness, adhesion strength and cross-sectional morphology of the obtained multilayer coatings were investigated. The results show that the Vickers hardness of Ti/TiN/Zr/ZrN multilayer coating, with a film thickness of 11.37 μm, is 29.36 GPa. The erosion and salt spray resistance performance of Cr_17Ni_2 steel substrates can be evidently improved by Ti/TiN/Zr/ZrN multilayer coating. The surface roughness of Cr_17Ni_2 steel substrates plays an important role in determining the mechanical and erosion performances of Ti/TiN/Zr/ZrN multilayer coatings. Overall, a low value of the surface roughness of substrates corresponds to an improved performance of erosion and salt spray resistance of multilayer coatings. The optimized performance of Ti/TiN/Zr/ZrN multilayer coatings can be achieved provided that the surface roughness of Cr_17Ni_2 steel substrates is lower than 0.4μm. 展开更多
关键词 Ti/TiN/zr/zrN multilayer coatings surface roughness sand erosion resistance corrosion resistance vacuum cathodicarc deposition TIN zrN
下载PDF
Adsorption of fluorine and chlorine on Mg(0001) surface:A density functional theory investigation 被引量:3
2
作者 段永华 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第6期1844-1852,共9页
The adsorption of low-coverage of F and Cl adatoms on the Mg(0001) surface was investigated using first-principles calculations based on the density functional theory(DFT).The stability of the(2×2) structur... The adsorption of low-coverage of F and Cl adatoms on the Mg(0001) surface was investigated using first-principles calculations based on the density functional theory(DFT).The stability of the(2×2) structures formed by halogen atoms adsorbed at different sites was determined.The difference between the adsorption of F and Cl on Mg(0001) surface was also discussed.The calculation results show that hollow sites are the energetically most favorable at the low-coverage.It can be concluded from the Mulliken charges and density of states that electrons transfer from the substrate Mg atoms to the adatoms,which leads to the formation of adsorbate bond and further causes the stronger interaction between Mg atom and adatom.The interaction between Cl and Mg atoms is weaker than the interaction between F and Mg. 展开更多
关键词 first principles HALOGENS F Cl Mg(0001 surface adsorption energy
下载PDF
DFT Study of the Effect of Temperature on ZnO Adsorbed on α-AI_2 O_3(0001)Surface
3
作者 杨春 余毅 李来才 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2006年第2期137-142,共6页
The adsorption and the growth of ZnO on α-Al2O3(0001) surface at various temperatures were theoretically calculated by using a plane wave pseudopotentials (USP) method based on density functional theory.The avera... The adsorption and the growth of ZnO on α-Al2O3(0001) surface at various temperatures were theoretically calculated by using a plane wave pseudopotentials (USP) method based on density functional theory.The average adsorption energy of ZnO at 400, 600 and 800 ℃ is 4.16±0.08, 4.25±0.11 and 4.05±0.23 eV respectively. Temperature has a remarkable effect on the structure of the surface and the interface of ZnO/α-Al2O3(0001). It is found that the Zn-hexagonal symmetry deflexion does not appear during the adsorption growth of ZnO at 400 ℃, and that the ZnO[10^-10] is parallel with the [10^-10] of the α-Al2O3(0001), which is favorable for forming ZnO film with the Zn-terminated surface. It is observed from simulation that there are two kinds of surface structures in the adsorption of ZnO at 600 ℃: one is the ZnO surface that has the Zn-terminated structure, and whose [10^-10] parallels the [10^-10] of the substrate surface, and the other is the ZnO[10^-10] //sapphire [11-20] with the O-terminated surface. The energy barrier of the phase transition between these two different surface structures is about 1.6 eV, and the latter is more stable. Therefore,the suitable temperature for the thin film growth of ZnO on sapphire is about 600 ℃, and it facilitates the formation of wurtzite structure containing Zn-O-Zn-O-Zn-O double-layers as a growth unit-cell. At 600 ℃, the average bond length of Zn-O is 0.190±0.01 nm, and the ELF value indicates that the bond of (substrate)-O-Zn-O has a distinct covalent character, whereas the (Zn)O-Al (substrate) shows a clear character of ionic bond. However, at a temperature of 800 ℃, the dissociation of Al and O atoms on the surface of the α-Al2O3(0001) leads to a disordered surface and interface structure. Thus, the Zn-hexagonal symmetry structure of the ZnO film is not observed under this condition. 展开更多
关键词 ZNO α-Al2O3(0001 surface ADSORPTION Density functional calculations
下载PDF
First-principles Calculations of H_2O Adsorption Reaction on the GaN(0001) Surface 被引量:2
4
作者 胡春丽 陈勇 李俊篯 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2009年第2期240-244,共5页
The adsorption and decomposition of H2O on GaN(0001) surface have been explored employing density functional theory (DFT). Two distinct adsorption features of H2O on GaN(0001) corresponding to molecular adsorpti... The adsorption and decomposition of H2O on GaN(0001) surface have been explored employing density functional theory (DFT). Two distinct adsorption features of H2O on GaN(0001) corresponding to molecular adsorption and H-OH dissociative adsorption are revealed by our calculations. The activities of the surface reactions of H2O on GaN(0001) surface are investigated. For the stepwise processes of H2O decomposition into H2 in gas phase and adsorbed O atom (H2O(g)→H2O(chem)→OH(chem) + H(chem)→2H(chem) + O(chem)→H2(g) + O(chem)), the first and second steps are facile and can even occur at room temperature; while the last two have high barriers and thus are difficult to proceed, especially the fourth step is endothermic. In short, H2O adsorption and decomposition into H2 in gas phase and adsorbed O atom on GaN(0001) surface are exothermic by -43.98 kcal/mol. 展开更多
关键词 H2O GaN(0001 surface DFT ADSORPTION REACTION
下载PDF
Water adsorption on the Be(0001) surface:from monomer to trimer adsorption 被引量:2
5
作者 Ning Hua Tao Xiang-Ming Tan Ming-Qiu 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第1期389-398,共10页
In this paper, the density functional theory has been used to perform a comparative theoretical study of water monomer, dimer, trimer, and bilayer adsorptions on the Be(0001) surface. In our calculations, the adsorb... In this paper, the density functional theory has been used to perform a comparative theoretical study of water monomer, dimer, trimer, and bilayer adsorptions on the Be(0001) surface. In our calculations, the adsorbed water molecules are energetically favoured adsorbed on the atop sites, and the dimer adsorption is found to be the most stable with a peak adsorption energy of - 437 meV. Further analyses have revealed that the essential bonding interaction between the water monomer and the metal substrate is the hybridization of the water 3al-like molecular orbital with the (s, P2) orbitals of the surface beryllium atoms. While in the case of the water dimer adsorption, the lbz-like orbital of the H2O molecule plays a dominant role. 展开更多
关键词 Be(0001)/H2O surface adsorption energy electronic structure
下载PDF
The First-principles Calculations of H_2S Adsorption and Decomposition on the ZnO(0001) Surface 被引量:1
6
作者 尹改玉 丁开宁 李俊篯 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2010年第8期1139-1146,共8页
The adsorption and decomposition of H2S on the ZnO(0001) surface have been investigated with first-principles calculations.The results reveal that H2S is dissociatively adsorbed on the clean ZnO(0001) surface to g... The adsorption and decomposition of H2S on the ZnO(0001) surface have been investigated with first-principles calculations.The results reveal that H2S is dissociatively adsorbed on the clean ZnO(0001) surface to generate HS-and hydrogen species.To our interest,as indicated by Mulliken charge and density of states of the configuration calculation,the bonding mechanism of H2S on the ZnO(0001) surface can involve the donation of charge from the "s lone pairs" into the surface and the back donation of surface electrons to H2S.Therefore,the electrons should play an important role in decomposition.Furthermore,the reactivity of H2S adsorption and further thermal decomposition reactions on the ZnO(0001) surface have also been discussed by calculating the possible reaction pathways.As expected,H2 will be easily generated during the decomposition process. 展开更多
关键词 ZnO 0001 surface hydrogen sulfide DFT DECOMPOSITION thermal decomposition
下载PDF
Surface modifications of biometallic commercially pure Ti and Ti–13Nb–13Zr alloy by picosecond Nd:YAG laser 被引量:2
7
作者 Slađana Laketić Marko Rakin +3 位作者 MilošMomčilović Jovan Ciganović Đorđe Veljović Ivana Cvijović-Alagić 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2021年第2期285-295,共11页
The effects of picosecond Nd:YAG laser irradiation on chemical and morphological surface characteristics of the commercially pure titanium and Ti–13Nb–13Zr alloy in air and argon atmospheres were studied under diffe... The effects of picosecond Nd:YAG laser irradiation on chemical and morphological surface characteristics of the commercially pure titanium and Ti–13Nb–13Zr alloy in air and argon atmospheres were studied under different laser output energy values.During the interaction of laser irradiation with the investigated materials,a part of the energy was absorbed on the target surface,influencing surface modifications.Laser beam interaction with the target surface resulted in various morphological alterations,resulting in crater formation and the presence of microcracks and hydrodynamic structures.Moreover,different chemical changes were induced on the target materials’surfaces,resulting in the titanium oxide formation in the irradiation-affected area and consequently increasing the irradiation energy absorption.Given the high energy absorption at the site of interaction,the dimensions of the surface damaged area increased.Consequently,surface roughness increased.The appearance of surface oxides also led to the increased material hardness in the surface-modified area.Observed chemical and morphological changes were pronounced after laser irradiation of the Ti–13Nb–13Zr alloy surface. 展开更多
关键词 commercially pure titanium Ti-13Nb-13zr alloy surface modification Nd:YAG laser laser-induced damage hard oxidized surface
下载PDF
Density Functional Theory Study for Adsorption of Oxygen and Water Molecules on 6H-SiC(0001) Surface 被引量:2
8
作者 Chun-he Fu Hui-li Lu Shao-rui Sun 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2019年第4期451-456,I0002,I0003,共8页
6H-SiC is an important semiconductor material. The 6H-SiC wafer is always exposed to a high-humidity environment and the effect from the absorbed water molecule and some relative adsorbates is not negligible. Here, th... 6H-SiC is an important semiconductor material. The 6H-SiC wafer is always exposed to a high-humidity environment and the effect from the absorbed water molecule and some relative adsorbates is not negligible. Here, the oxygen and water molecules absorbed on the 6H-SiC(0001) surface and the dissociation process were studied with density functional theory. On the 6H-SiC(0001) surface, absorbed O2 is spontaneously dissociated into O*, which is absorbed on a hollow site, and further transforms the 6H-SiC(0001) surface into SiO2. The absorbed H2O is spontaneously broken into OH*and H*, which are both absorbed on the top of the Si atom, and OH* is further reversibly transformed into O* and H*. The H* could saturate the dangling Si bond and change the absorption type of O*, which could stabilize the 6H-SiC(0001) surface and prevent it from transforming into SiO2. 展开更多
关键词 6H-SiC(0001) surface H2O absorption Dangling Si bond Stability Density functional theory
下载PDF
Photocatalytic Dissociation of CH3OH on ZnO(0001) Surface
9
作者 Peng-xiao Liang Fei Xu +4 位作者 Zhen-xing Li Zhi-wen Luan Xing-an Wang Qing Guo Xue-ming Yang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2019年第5期525-530,共6页
Photocatalysis of CH3OH on the ZnO(0001) surface has been investigated by using temperature-programmed desorption (TPD) method with a 266 nm laser light. TPD results show that part of the CH3OH adsorbed on ZnO(0001) s... Photocatalysis of CH3OH on the ZnO(0001) surface has been investigated by using temperature-programmed desorption (TPD) method with a 266 nm laser light. TPD results show that part of the CH3OH adsorbed on ZnO(0001) surface are in molecular form, while others are dissociated. The thermal reaction products of H2, CH3·, H2O, CO, CH2O, CO2 and CH3OH have been detected. Experiments with the UV laser light indicate that the irradiation can promote the dissociation of CH3OH/CH3O· to form CH2O, which can be fu- ture converted to HCOO- during heating or illumination. The reaction between CH3OHZn and OHad can form the H2O molecule at the Zn site. Both temperature and illumination promote the desorption of CH3· from CH3O·. The research provides a new insight into the photocatalytic reaction mechanism of CH3OH on ZnO(0001). 展开更多
关键词 Methanol Photocatalysis ZnO(0001) surface Temperature-programmed DESORPTION
下载PDF
A DFT Study of Alkenes and Alkynes Reacting with H-GaN (0001) Surface
10
作者 胡春丽 陈勇 +1 位作者 李俊篯 章永凡 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2009年第1期125-131,共7页
The addition reactions of alkenes and alkynes to the H-terminated GaN (0001) surface with a Ga dangling-bond have been studied employing periodic density functional theory (PDFT) calculations. Detailed information... The addition reactions of alkenes and alkynes to the H-terminated GaN (0001) surface with a Ga dangling-bond have been studied employing periodic density functional theory (PDFT) calculations. Detailed information on the reaction pathways of these alkenes and alkynes with H-GaN (0001) surface is provided, which indicates that the reactions contain two steps separated by the metastable intermediates: elementary addition reaction and H-abstraction process. From the energy curves, the reactions are clearly viable in the cases of ethene, styrene and phenylacetylene; while for ethyne, the H-abstraction barrier is higher than the desorption barrier of the intermediate, so the adsorbed C2H2 in intermediate is more likely to be desorbed back into the gas phase than to form a stable adsorbed species. Furthermore, it is obvious that for either alkenes or alkynes, the systems substituted by phenyl have more stable intermediates because π conjugation could improve their stabilities. 展开更多
关键词 ALKENES ALKYNES H-GaN 0001 surface DFT reaction pathway
下载PDF
First-principles study on properties and electron structure of CrB_2(0001) surface
11
作者 ZHUO Zi-ming MAO Hong-kui XU Hong 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2018年第1期98-102,共5页
Based on a first-principles density functional plane-wave ultrasoft pseudopotential method,the surface properties of two different types of terminated CrB2(0001)are calculated and compared,such as surface relaxation,s... Based on a first-principles density functional plane-wave ultrasoft pseudopotential method,the surface properties of two different types of terminated CrB2(0001)are calculated and compared,such as surface relaxation,surface energy and electricity structure.The results of surface relaxation show surface interlayer distance converges rapidly for both terminated CrB2(0001)when the number of the atoms layers reaches 9.Through analysis of charge density difference and partial density of states(PDOS),it can be concluded that CrB2(0001)models with B termination have smaller interface energy,stronger electronic interaction than another models and the form of termination is more stable. 展开更多
关键词 density functional calculations(DFT) surface relaxation surface energy CrB2(0001)
下载PDF
Influence of Rolling Temperature in Supercooled Liquid Region on the Surface Morphology of Zr_(52.5)Al_(10)Ni_(10)Cu_(15)Be_(12.5) Bulk Metallic Glass
12
作者 王国明 方守狮 +1 位作者 华勤 肖学山 《Journal of Shanghai University(English Edition)》 CAS 2005年第5期458-461,共4页
Surface morphologies of Zr52.5 Al10 Ni10 Cu15 Be12.5 bulk metallic glass after being rolled at both a temperature around T9 and near ( Tx - 50) K were investigated with a scanning electron microscopy. Macroscopic an... Surface morphologies of Zr52.5 Al10 Ni10 Cu15 Be12.5 bulk metallic glass after being rolled at both a temperature around T9 and near ( Tx - 50) K were investigated with a scanning electron microscopy. Macroscopic and microscopic observation results show that squamae, cracks, steps and wedges exist on the surface when the samples were rolled at temperatures around Ty. However, a smooth and fiat surface appears when the samples were rolled at temperatures near ( Tx - 50) K. These results indicate that the mode of deformation in the supercooled liquid region is a partially homogeneous flow at a temperature around T9, and a fully homogeneous one at temperatures near ( Tx - 50) K. According to the results, it is more feasible to roll the amorphous alloys at temperatures near ( Tx - 50) K to obtain parts with smooth and fiat surface. 展开更多
关键词 rolling temperature supercooled liquid region surface morphology zr52.5Al10Ni10Cu15Be12.5 deformation mechanism.
下载PDF
Zr(0001)初始氧化的表面结构变化
13
作者 周牧易 Y.M.Wang +3 位作者 P.C.Wong W.T.Moore D.T.V.U Grimsby K.A.R.Mitchell 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 1992年第2期170-175,共6页
LEED和XPS实验观察到了Zr(0001)初始氧化的表面结构变化,多重散射理论分析结构表明,Zr(0001)表面的初始氧化形成的(2×2)表面结构,为表面FCC重构的underlayer的C(B) A(C)BAB的结构形式,并存在纵向的原子的Relaxation,使Zr原子移向O... LEED和XPS实验观察到了Zr(0001)初始氧化的表面结构变化,多重散射理论分析结构表明,Zr(0001)表面的初始氧化形成的(2×2)表面结构,为表面FCC重构的underlayer的C(B) A(C)BAB的结构形式,并存在纵向的原子的Relaxation,使Zr原子移向O原子,计算的最佳模型中的位移量为d_(11)=0.005nm,d_(22)=0.005 nm。 展开更多
关键词 低能电子衍射 表面结构
下载PDF
Keggin Structure and Surface Acidity of 12-Phosphotungstic Acid Grafted Zr-MCM-48 Mesoporous Molecular Sieves
14
作者 Zhiqi Wang Juan Navarrete 《World Journal of Nano Science and Engineering》 2012年第3期134-141,共8页
A zirconium modified MCM-48 mesoporous material was synthesized by surfactant-templated method. Surface grafting Zr-MCM-48 with tungstophosphoric acid led to a great enhancement of both the number of the Br?nsted acid... A zirconium modified MCM-48 mesoporous material was synthesized by surfactant-templated method. Surface grafting Zr-MCM-48 with tungstophosphoric acid led to a great enhancement of both the number of the Br?nsted acid sites and acidity strength in comparison with the bare support. At 100°C, the 30 wt% H3PW12O40/Zr-MCM-48 contained 174 μmol/g Br?nsted acid sites which were 14.5 times greater than that of Zr-MCM-48. The Keggin structure of the grafted heteropolyacid was rather stable after calcination at 400°C for 2 h, approximately 93.3% of Keggin structure in the dispersed heteropolyacid were remained without destruction but slightly distorted in some degree, as evidenced by FTIR characterization and 31P NMR-MAS analysis. This H3PW12O40/Zr-MCM-48 solid with three dimensional mesoporous system, large surface area and very strong Br?nsted acidity will be a promising catalyst for acid catalytic reactions. 展开更多
关键词 zr-MCM-48 surface ACIDITY HETEROPOLYACID SPECTROSCOPIC CHARACTERIZATION
下载PDF
Crack elimination and strength enhancement mechanisms of selective laser melted Si-modified Al−Mn−Mg−Er−Zr alloy
15
作者 Jiang YU Yao-xiang GENG +2 位作者 Hong-bo JU Zhi-jie ZHANG Jun-hua XU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第8期2431-2441,共11页
In order to increase the processability and process window of the selective laser melting(SLM)-fabricated Al−Mn−Mg−Er−Zr alloy,a novel Si-modified Al−Mn−Mg−Er−Zr alloy was designed.The effect of Si alloying on the sur... In order to increase the processability and process window of the selective laser melting(SLM)-fabricated Al−Mn−Mg−Er−Zr alloy,a novel Si-modified Al−Mn−Mg−Er−Zr alloy was designed.The effect of Si alloying on the surface quality,processability,microstructure,and mechanical properties of the SLM-fabricated alloy was studied.The results showed that introducing Si into the Al−Mn−Mg−Er−Zr alloy prevented balling and keyhole formation,refined the grain size,and reduced the solidification temperature,which eliminated cracks and increased the processability and process window of the alloy.The maximum relative density of the SLM-fabricated Si/Al−Mn−Mg−Er−Zr alloy reached 99.6%.The yield strength and ultimate tensile strength of the alloy were(371±7)MPa and(518±6)MPa,respectively.These values were higher than those of the SLM-fabricated Al−Mn−Mg−Er−Zr and other Sc-free Al−Mg-based alloys. 展开更多
关键词 selective laser melting Al−Mn−Mg−Er−zr−Si alloy surface roughness PROCESSABILITY mechanical properties
下载PDF
氢原子在Ru(0001)表面的化学吸附 被引量:5
16
作者 陈鑫 陈文斌 +3 位作者 尚学府 陶向明 戴建辉 谭明秋 《物理化学学报》 SCIE CAS CSCD 北大核心 2007年第6期861-866,共6页
用密度泛函理论研究了氢原子的污染对于Ru(0001)表面结构的影响.通过PAW(projector-augmented wave)总能计算研究了p(1×1)、p(1×2)、(3~(1/2)×3~(1/2))R30°和p(2×2)等几种氢原子覆盖度下的吸附结构,以及在... 用密度泛函理论研究了氢原子的污染对于Ru(0001)表面结构的影响.通过PAW(projector-augmented wave)总能计算研究了p(1×1)、p(1×2)、(3~(1/2)×3~(1/2))R30°和p(2×2)等几种氢原子覆盖度下的吸附结构,以及在上述结构下Ru(0001)面fcc(面心立方)格点和hcp(六方密堆)格点的氢原子吸附.所得结果表明,在p(1×1)-H、p(1×2)-H、(3~(1/2)×3~(1/2))R30°-H和p(2×2)-H几种H原子覆盖度下,以p(1×1)-H结构单个氢原子吸附能为最大.在p(1×1)-H吸附结构下,由于氢原子吸附导致的Ru(0001)表面第一层Ru原子收缩的理论计算数值分别为-1.11%(hcp吸附)和-1.55%(fcc吸附),因此实际上最有可能的情况是两种吸附方式都有一定的几率.而实验中观察到的“清洁”Ru(0001)表面实际上是有少量氢原子污染的表面.不同覆盖度和氢分压下氢原子吸附的污染对Ru(0001)表面结构有极大的影响,其表面的各种特性都会随覆盖度的不同而产生相应的变化. 展开更多
关键词 Ru(0001)表面 氢原子吸附 表面污染
下载PDF
机械研磨处理Zr-4合金表面纳米化研究 被引量:13
17
作者 张聪惠 兰新哲 +1 位作者 赵西成 段晓鸽 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2010年第3期511-514,共4页
选用表面机械研磨技术(SMAT)处理密排六方结构Zr-4合金的表面,实现Zr-4表面纳米化,并利用X射线衍射(XRD)对比分析不同时间SMAT处理Zr-4合金表面平均晶粒尺寸。SMAT处理15min时Zr-4合金表面平均晶粒尺寸最小,约为20nm。利用光学显微镜(OM... 选用表面机械研磨技术(SMAT)处理密排六方结构Zr-4合金的表面,实现Zr-4表面纳米化,并利用X射线衍射(XRD)对比分析不同时间SMAT处理Zr-4合金表面平均晶粒尺寸。SMAT处理15min时Zr-4合金表面平均晶粒尺寸最小,约为20nm。利用光学显微镜(OM)、透射电镜(TEM)、高分辨透射电镜(HRTEM)对其纳米化表层结构进行表征,并研究了其表面纳米化机制。 展开更多
关键词 zr-4合金 表面机械研磨 表面纳米化 位错 孪晶
下载PDF
水在石墨(0001)面簇模型桥位上吸附的量子化学研究 被引量:6
18
作者 傅爱萍 冯大诚 邓从豪 《高等学校化学学报》 SCIE EI CAS CSCD 北大核心 1998年第5期792-795,共4页
用从头计算方法对水在石墨(0001)面桥位上的吸附进行了研究.用C6H8原子簇模拟石墨表面,在6-31G*水平上计算了水在不同方向和位置上的吸附能量.研究表明:水在石墨面上的吸附很弱,属于物理吸附;在中性或带负电荷的... 用从头计算方法对水在石墨(0001)面桥位上的吸附进行了研究.用C6H8原子簇模拟石墨表面,在6-31G*水平上计算了水在不同方向和位置上的吸附能量.研究表明:水在石墨面上的吸附很弱,属于物理吸附;在中性或带负电荷的石墨表面,当水分子中的氢原子靠近石墨面时,体系存在能量最小值,而在带正电荷的表面,当氧原子靠近石墨面时存在稳定的吸附点;不论表面带正电荷还是带负电荷,均对水分子的吸附起增强作用. 展开更多
关键词 从头计算 石墨(0001)表面 吸附 石墨表面
下载PDF
氢原子在Ti(0001)表面吸附的密度泛函理论研究 被引量:3
19
作者 陈文斌 陶向明 +1 位作者 赵新新 谭明秋 《物理化学学报》 SCIE CAS CSCD 北大核心 2006年第4期445-450,共6页
用密度泛函理论研究了氢原子的污染对于Ti(0001)表面结构的影响.通过PAW总能计算研究了p(1×1)、p(1×2)、("3×"3)R30°和p(2×2)等几种氢原子覆盖度下的吸附结构,以及在上述结构下Ti(0001)面fcc格点和... 用密度泛函理论研究了氢原子的污染对于Ti(0001)表面结构的影响.通过PAW总能计算研究了p(1×1)、p(1×2)、("3×"3)R30°和p(2×2)等几种氢原子覆盖度下的吸附结构,以及在上述结构下Ti(0001)面fcc格点和hcp格点的氢原子吸附.结果表明,在p(1×1)-H、p(1×2)-H、("3×"3)R30°-H和p(2×2)-H几种H原子覆盖度下,以p(1×1)-H结构的单个氢原子吸附能为最大.在p(1×1)-H吸附结构下,由于氢原子吸附导致的Ti(0001)表面Ti原子层收缩的理论计算数值分别为-2.85%(hcp吸附)和-4.31%(fcc吸附),因此实际上最有可能的情况是两种吸附方式都有一定的几率.而实验中观察到的所谓“清洁”Ti(0001)表面实际上是有少量氢原子污染的表面.不同覆盖度和氢分压下,氢原子吸附的污染对Ti(0001)表面结构有极大的影响,其表面的各种特性都会随覆盖度的不同而产生相应的变化. 展开更多
关键词 Ti(0001)表面 氢原子吸附 表面污染
下载PDF
α-Al_2O_3(0001)表面弛豫及其对表面电子态的影响 被引量:8
20
作者 杨春 余毅 +1 位作者 李言荣 刘永华 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2004年第5期537-542,共6页
在周期边界条件下的κ空间中 ,采用基于密度泛函理论的局域密度近似平面波超软赝势法 ,对最外表面终止层为单层Al的α Al2 O3 超晶胞 (2× 2 ) (0 0 0 1)表面结构进行了弛豫与电子结构计算研究 .结果表明 ,最外表面Al-O层有较大的弛... 在周期边界条件下的κ空间中 ,采用基于密度泛函理论的局域密度近似平面波超软赝势法 ,对最外表面终止层为单层Al的α Al2 O3 超晶胞 (2× 2 ) (0 0 0 1)表面结构进行了弛豫与电子结构计算研究 .结果表明 ,最外表面Al-O层有较大的弛豫 ,明显地影响了表面原子与电子结构 ,布居分析表明表面电子有更大的几率被定域在O原子的周围 ,表现出O的表面态 .进一步分析了表面弛豫前后表面电子密度、态密度变化 ,表面能级分裂主要来自于O的 2 p轨道电子态变化 .通过对比弛豫前后的表面电子局域函数 (ELF)图 ,分析了表面成键特性 . 展开更多
关键词 表面弛豫 态密度 a-Al2O3 电子密度
下载PDF
上一页 1 2 8 下一页 到第
使用帮助 返回顶部