Metal-C60 Interface Interaction: Effects on Metal Dispersion in Co-Deposited Films

Abstract

In case of a metal finely dispersed in a C₆₀ matrix, the metal-to-C₆₀ charge transfer lowers the interface energy. The total cohesive energy per metal atom E_tot was estimated for Au clusters in fullerite. The results show that, for a charge Q_f ≥ 1 electron (e) transferred from the metal clusters to each C₆₀ cage, a minimum appears in E_tot, defining a most stable cluster size. Thereby, the equilibrium dispersion state of the metal in the fullerite matrix depends on Q_f.     

Thermomechanical Interaction in Metal Films during Ultrashort Laser Heating

An ultrafast thermoelasticity based on a hyperbolic two-step heat conduction model with electron-phonon interaction is applied to investigate the thermomechanical response of five immense homogeneous, isotropic gold films (20 nm, 100 nm, 200 nm, 500 nm, and 2 μm) impacted under femtosecond laser pulses by using finite element method (FEM). Finite element governing equations are established and solved in the time domain directly. The results, including electron temperature, lattice temperature, displacements, stresses, and strains, are presented graphically. The effect of thickness of thin films is studied; in addition, characteristics of stress evolution and displacement development in thin films are obtained. Finally, the influence of hot-electron blast force and thermal-mechanical coupling term are studied.     

五种二元过渡金属氧化物界面上的相互作用、非晶相结构及催化性能(Ⅰ) 界面非晶相分散作用及体相晶相剩余率的提出

通过固相热反应，以十种不同配比和不同的焙烧制度，在MoO3中分别掺杂Fe2O3、V2O5、TiO2(锐钛矿型）、WO3和ZrO2，制得五种二元氧化物的系列试样。应用XRD、BET、FT-IR、DSC、半导体气敏特性和催化反应探针等表征技术，较系统地研究了这些组分氧化物形成二元氧化物时界面的非晶相分散结构及催化性能，并提出了相应的亚单层的非晶相分散模型。本文首先报道应用XRD，FT-IR和BET表征界面的非晶相分散。研究结果发现，各个组分氧化物的表面大小不同，但每一对组分氧经物在相互掺杂时，在界面上发生了组分氧化物的亚单分子层（meta-monolayer)的非晶相分散以及某些表面化学反应，前者在非晶相含量具有本征性的分散阈值，后者则生成新的化学物种。根据BET比表面积，求算了各组分氧化物在不同二元氧化物中每100m^2的不同的非晶相分散阈值。XRD晶相定量分析和FT-IR差谱法（the differential spectra method)联合证明了非晶相新物种的存在，首次发现非晶相新物种的IR特征吸收峰与分子键价结构的关联。     

Effects of Annealing on the Conductivity of C60 Thin Films

Films of C₆₀, at different stages of annealing of T_t=200°and 300°C have been electrically characterized over the temperature domain from -130°C to T_t. X-ray diffraction revealed a random polycrystalline fee structure with stacking defects of an intrinsic nature, due to deposition conditions. The value of room-temperature conductivity was found to be in the range (6.3-1.0) *10^-10 (0cm)^-1. In the stable annealed state the conductivity showed an activated temperature dependence above 423 K and a non-activated dependence below 330-280 K. The activation energies E_a = 0.8 eV (film thickness 0.70 μm) and E_a = 1.0 eV (film thickness 2.40 μm) were in good agreement with the energy gap values (1.63 eV and 2.08 eV) which were deduced from the absorption spectral dependence. Annealing decreased the non-activated contribution to conduction, extending the intrinsic conduction temperature range.     

Magnetic Anisotropy Dispersion in FeCo Films

We report on our study of magnetic and nonmagnetic parameters such as coercivity, anisotropy , magnetic dispersion, and stress on FeCo films of various thicknesses from 25 A to 500 A . We used 10 A Ru or NiFe seed layers for two sets of FeCo films. All films showed so-called hard-axis coercivity rocking, i.e., the hard-axis coercivity exhibits two local minima close to the nominal hard axis. Magnetic properties and stress change dramatically with FeCo thickness, but with little difference between the two types of seed materials. We found a correlation between the angular separation of the two local coercivity minima and easy-axis coercivity. The results stress the need to differentiate between two levels of dispersion, one at the microscopic and the other at the macroscopic level.     

Stacking Defects in C60 Films

The structure of pollycrystalline C₆₀ films prepared by sublimation from 99.9% pure C₆₀ powder and from graphite soot was investigated by X-ray diffraction. A complex fcc (111) line was found in the former samples. Comparison of experimental and simulated (111) profiles allowed to assess quantitatively the degree of stacking disorder introduced during the growth of the film. Probabilities could be derived for continuation of already started fcc and hep sequences, thereby characterizing the statistical microstructure of the C₆₀ films. Also, the relative magnitudes of inter- and intra-layer disorder can be estimated. The films deposited from graphite soot show a high structural disorder.     

五种二元过渡金属氧化物界面上的相互作用、非晶相结构及催化性能(Ⅱ)DSC、半导体气敏特性、催化活性与亚单层分散模型

应用DSC、半导体气敏特性、催化活性及亚单(分子)层分散模型共四项表征技术,进一步研究了五种二元氧化物的界面结构及其特性.DSC曲线的放热峰及吸热峰分别与界面化学反应、晶格畸变和瓦解、熔化、烧结以及固溶体的形成相关.导电性能的测试证明这些二元氧化物属于N-型半导体,对邻二甲苯具有气敏特性,其灵敏度在化学吸附的初期阶段与邻二甲苯蒸气浓度呈线性关系.催化选择性及转化率的测定证明V2O52MoOs及WO3-MoOs体系对邻二甲苯选择性氧化为苯酐具有催化活性,其非晶相MoOs及V2O5的活性较为显著,尤其当二元氧化物的组成接近分散阈值Dt时,选择性最佳.为了解释大的分散阈值Dt与小的比表面积之间的关系,经计算机编程计算,在分子水平及纳米尺度上提出了球形八面体密置的亚单层分散模型并求得了模型的七个参数.通过讨论亚单层分散与非晶相结构之间的关系,提出了晶相损失的机理以及作为催化剂的非晶相结构对热的亚稳特性.     

C_（60）－AALB膜光学累积和记录效应的研究

Ｃ＿（６０）是碳的第三种同素异构体。本文将Ｃ＿（６０）和花生酸混合制得高质量的Ｃ＿（６０）－花生酸复合ＬＢ多层膜，在对其光学非线性特性的研究中首次发现这种ＬＢ膜具有光学累积和记录效应。采用布居光栅模型，分析了这种ＬＢ膜中的光学累积和记录效应的机制。     

Electrons Above Helium Films on Metal Substrates

We report about our investigations on two-dimensional electron ensembles floating above thin helium films supported by metallic substrates. We found a surprisingly high stability of these electrons, although the substrates were conducting which allows breakthrough at weak spots of the helium film due to roughness peaks. We have measured the electron densities and corresponding relaxation times. By pulling the electrons from the area above the loading electrode to the area above a separate electrode one can enhance the lifetime of these surface state electrons. PACS numbers: 67.70.+n, 73.90.+f, 73.50.-h     

基于意象的交互界面动效设计方法研究

目的提出基于意象的动效设计方法,强化品牌调性,丰富并优化用户体验。方法分析交互动效表现的5个元素,及构成意象的3个特征,根据格式塔主张的"同形同构"说,提出了实现动效意象化的设计方法。结果通过智能电视设计案例,初步验证了基于意象的交互动效设计流程的可行性。结论基于意象的交互设计是在产品与用户之间建立想象空间,使得体验更加感性,交互行为更易于理解和学习,交互过程更富趣味,在用户与产品之间建立更深刻的互动。     

Interface Study of Metal Electrode and Semiconducting Carbon Nanotubes: Effects of Electrode Atomic Species

Presented herein are the first-principle calculations of the transport and other pertinent electronic properties of metal contacted semiconducting carbon nanotubes (CNTs). The investigation is focused on elucidating access resistance as a function of the work function difference and the chemical nature of the metal atomic species. Our results show that, for simple end-contact geometries, the Fermi level position within the gap differs between palladium-contacted CNTs and gold-contacted CNTs. This is interesting since both of these metals possess similar work functions. The role of the metal-CNT coupling is examined in light of the resulting - behavior of the system.     

钼片上CVD金刚石膜的界面研究

借助金相显微镜，ＳＥＭ、ＥＤＸＡ对钼片上ＣＶＤ金刚石膜的界面形貌和成分进行了研究，对比了加磁场与不加磁场所沉积的金刚石膜的横民面形态特征，结果表明：加磁场与否在ＣＶＤ金刚石膜和钼基体之间均存在数μｍ厚的Ｍｏ２Ｃ中间层，它呈细小柱状昌方式生长，该层以下的钼基体发生了再结晶细化；加磁场沉积的金刚石膜较致密，（显微）空隙数量较小、金刚石颗粒尺寸较小、金刚石膜背面粘附较多的Ｍｏ２Ｃ聚集物。压痕试验法评定的     

A Self-Healing Amalgam Interface in Metal Batteries

Poor cyclability and safety concerns caused by the uncontrollable dendrite growth and large interfacial resistance severely restrict the practical applications of metal batteries. Herein, a facile, universal strategy to fabricate ceramic and glass phase compatible, and self-healing metal anodes is proposed. Various amalgam-metal anodes (Li, Na, Zn, Al, and Mg) show a long cycle life in symmetric cells. It has been found that liquid Li amalgam shows a complete wetting with the surface of lanthanum lithium titanate electrolyte and a glass-phase solid-state electrolyte. The interfacial compatibility between the lithium metal anode and solid-state electrolyte is dramatically improved by using an in situ regenerated amalgam interface with high electron/ion dual-conductivity, obviously decreasing the anode/electrolyte interfacial impedance. The lithium-amalgam interface between the metal anode and electrolyte undergoes a reversible isothermal phase transition between solid and liquid during the cycling process at room temperature, resulting in a self-healing surface of metal anodes.     

Optical Transition in Reduced C60 Thin Films

Absorption spectra of C60 thin film reduced in an electrochemical cell are studied. The results are compared with data of chemically reduced C60 anions. Absorption with relatively broad line-width below the energy of 1 eV is observed in the film besides the peaks at 1.14 ∼ 1.4 eV observed in C60 anion solution. The electronic states of reduced COT are discussed in terms of the solid state effect.     

C60-PMMA复合膜的纳米结构研究

采用化学有机沉积法,在Ｓｉ（１００）、ＫＢｒ压片及微栅衬底上分别制备了 Ｃ_６０／ＰＭＭＡ重量比不同的Ｃ_６０－ＰＭＭＡ复合膜．红外光谱分析表明,Ｃ_６０分子已均匀地分布在Ｃ_６０－ＰＭＭＡ复合膜中．利用Ｘ射线衍射（ＸＲＤ）谱和透射电子显微镜（ＴＥＭ）研究了该复合膜的结构,结果显示原来均匀分布在ＰＭＭＡ中的Ｃ_６０分子经过扩散趋向于形成非晶或晶化的Ｃ_６０颗粒．经过退火,以面心立方结构单晶形式存在的Ｃ_６０颗粒的尺寸为３０～１００ｎｍ,且以规则的几何形体分散在ＰＭＭＡ连续相中．玻耳兹曼能量分布规律能够较好地解释,提高Ｃ_６０含量或退火温度,晶化Ｃ_６０颗粒尺寸增大的现象．     

Structure and Defects in Thin C60 Films

Thin C₆₀ films were deposited by vacuum sublimation of soot on single-crystal and amorphous substrates. The absence of higher fullerenes was confirmed by IR, Raman and UV-VIS spectroscopy. X-ray diffraction revealed a high density of stacking faults (probabilities in the range 10^-2), correlated with lattice distortions. Analysis of the UV-VIS absorption bands yielded values of the h_u → t_1g and h_u → t_1u optical gaps.     

Interface and Bulk Charge Localization in Manganite Thin Films

Nuclear magnetic resonance (NMR) is utilized to map the hyperfine fields acting on ⁵⁵Mn nuclei of La_2/3Sr_1/3MnO₃ (LSMO) epitaxial thin films. In contrast to early thoughts, we show that phase separation (PS) in LSMO is not restricted to an interface‐related dead‐layer only a few nm thick. Instead, it propagates much deeper into the films, thus signalling different origins for the PS. These results indicate that both, surfaces and defects contribute to promote distinguishable PS effects. This view has been confirmed by detailed ⁵⁵Mn NMR analysis of LSMO films where engineered bulk‐like defects have been created by appropriate irradiation by energetic He⁺ ions. Moreover, from the analysis of the restoring fields sensed by the spins of the ⁵⁵Mn nuclei, we infer two sources of magnetic anisotropy. More specifically, a surface magnetic anisotropy –linked to the interfacial dead layer– is predominant for ultrathin samples (t < 10 nm), whereas structural film relaxation, provides a second mechanism for anisotropy. These findings provide guidelines for the growth of electric and magnetic homogeneous manganite films.     

家用打印机人机界面信息交互设计的探讨

综合叙述了界面、人机界面概念,分析了硬件界面和软件界面信息交互设计的要点,探索新时代背景下界面信息交互的方向,总结了软件和硬件界面信息交互之间的关系,为家用打印机界面信息交互设计提出新的设计原则。     

Multiscale Modeling of Deformation in Polycrystalline Thin Metal Films on Substrates

The time‐dependent irreversible deformation of a thin metal film constrained by a substrate is investigated by a mesoscopic discrete dislocation simulation scheme incorporating information from atomistic studies of dislocation nucleation mechanisms. The simulations take into account dislocation climb along the grain boundaries in the film as well as dislocation glide along slip planes inclined and parallel to the film/substrate interface. The calculated flow stress and other features are compared with relevant experimental observations. The work is focused on deformation of a polycrystalline film without a cap layer, for which diffusive processes play an important role. The dislocation‐based simulations reveal information on the prevailing deformation mechanisms under different conditions and for different film thicknesses. Despite of the limitations of the two‐dimensional dislocation model, the simulations exhibit a film thickness dependent transition between creep dominated and dislocation glide dominated deformation, which is in good agreement with experimental observations.