User Interfaces for Applications on a Wrist Watch

Advances in technology have made it possible to package a reasonably powerful processor and memory subsystem coupled with an ultra high-resolution display and wireless communication into a wrist watch. This introduces a set of challenges in the nature of input devices, navigation, applications, and other areas. This paper describes a wearable computing platform in a wrist watch form-factor we have developed. We built two versions: one with a low resolution liquid crystal display; and another with a ultra high resolution organic light emitting diode display. In this paper we discuss the selection of the input devices and the design of applications and user interfaces for these two prototypes, and the compare the two versions.     

Full-Scale Testing of Procedures for Assembling Trunnion-Hub-Girder in Bascule Bridges

To simulate a trunnion-hub-girder (THG) assembly for bascule bridges, two full-scale laboratory tests were conducted for quantifying stresses at previously observed failure locations and for identifying a favorable assembly procedure. One assembly procedure, AP#1, cools the trunnion for a shrink fit into the hub, followed by cooling of the trunnion-hub assembly to shrink fit it into the girder. Using AP#1, development of cracks on the hub was observed in one THG assembly, and, in yet another assembly, the trunnion got stuck in the hub before full insertion could take place. Large hoop stresses and low temperatures were observed at the trunnion-hub interface when the trunnion-hub assembly was cooled for insertion into the girder. Since fracture toughness of THG parts decreases with temperature, allowable crack lengths were small. In an alternative assembly procedure, AP#2, where the hub is shrink fitted into the girder first, followed by cooling the trunnion and shrink fitting it into the hub-girder assembly, the allowable crack length was determined to be double the allowable crack length of AP#1. Hence, for the given full-scale geometry and interference values, assembly procedure AP#2 was found to be better than AP#1.     

Investigation of the atomic-scale friction and energy dissipation in diamond using molecular dynamics

We have used molecular dynamics simulations to examine friction when two diamond (111) surfaces are placed in sliding contact. The essence of atomic-scale friction was shown to be the mechanical excitation (in the form of vibrational and rotational energy) of the interface lattice layers upon sliding. This excitation was propagated to the rest of the lattice, and eventually dissipated as heat. In general, this excitation increases with increasing applied load; therefore, the atomic-scale friction also increases with load. Flexible hydrocarbon species, chemically bound to the diamond surface, can lead to a significant reduction of mechanical excitation upon sliding at high loads, leading to lower friction. In addition to clarifying the effects of chemically-bound hydrocarbon groups on atomic-scale friction at diamond interfaces, these simulations might also yield insight into more complicated systems, e.g. Langmuir-Blodgett films, and aid in the design of low-friction coatings.     

同时反演两个三维密度界面的拟神经网络BP算法

两个界面或多界面重力异常的显著特点是异常的不可分离性，即不能简单地根据异常的幅值和水平宽度等数理特点将两个界面或多个界面的异常区分开来，直接用两个三维密度界面的叠加重力异常同时反演两个界面埋深和起伏形态是本文的特色之一，借助于快速正演算法，对界面进行详细的单元划分，使反演结果更为精细，由于采用带输出反馈抑制策略和拟神经网络ＢＰ算法，使本反方法收敛性好，收敛速度快，拟ＢＰ算法借用了神经网络的并行，自     

Non-linear optical spectroscopy of interfaces: adsorption sites of a self-assembled alkyl thiol monolayer/Au(111)

We have used infrared-visible sum-frequency generation (SFG) to probe spectroscopically the interfacial structure of a self-assembled monolayer of alkyl thiol on a Au(111) surface. The SFG spectra of the CH₃ group, measured as a function of azimuthal angle, is not consistent with sulfur atoms being situated at sites of a single type, e.g. hollow or bridge, but is consistent with a mixed arrangement.     

X-ray techniques using synchrotron radiation in materials analysis

The extraordinary properties of SR have opened up new horizons for all techniques which use vacuum ultraviolet light and X-rays. In this article, some applications of SR in materials science have been discussed. X-ray absorption spectroscopy is a local, atom specific probe of the geometrical and electronic structure of the absorbing species. As an example, the lattice site location and the valence of Co in a doped high-T_c, superconductor YBa₂Cu_2–5Co_0–5O_7–4 has been discussed.     

MoSi_2硅化物的形成及电子结构的研究

利用XPS、UPS、AES、X-光衍射和拉曼散射等技术,研究了在稳态热退火条件下共溅射的Mo-Si合金膜,硅化物的形成及电子结构特性.     

The analysis of the current–voltage characteristics of the high barrier Au/Anthracene/n-Si MIS devices at low temperatures

The Au/Anthracene/n-Si/Al MIS device was fabricated on the basis of anthracene film covalently bonded to a Si substrate. The MIS device showed Schottky behavior with barrier heights of 0.85 eV and ideality factors of 1.88 at 300 K. The barrier height of the Au/n-Si has increased after deposition of the anthracene layer onto Si. Temperature dependent current–voltage (I–V) measurements were performed on the Au/Anthracene/n-Si/Al MIS diodes in the range 140–300 K. From the temperature dependence of forward bias I–V, the barrier height was observed to increase with temperature. However, the ideality factor decreased with increasing temperature. The values of activation energy (E_a) and Richardson constant (A*) were determined as 0.24 eV and 7.57 × 10⁻⁶ A cm⁻² K⁻² from the slope and the intercept at ordinate of the linear region of Richardson plot, respectively. The increase of the series resistance R_s with the fall of temperature was attributed to lack of free carrier concentration at low temperatures.     

Electrical and rheological properties of PMMA/LDPE blends filled with carbon black

Conductive immiscible multiphase blends of PMMA/LDPE filled with carbon black (CB) were studied in this work. Thermo-electrical behavior of the blends was compared with the composites made up of individual polymers in the blend, PMMA and LDPE filled with CB. The conductivity of the immiscible binary blend at different CB content was followed and modeled using a model circuit in which resistors resembling different phases and the interface between them present in the blend. Electrical percolation threshold was measured for the blend and compared with the single component polymers in order to judge the preferred phase for CB distribution in it. Rheological network formation by CB particles in the blend was also studied using dynamic rheology. The effect of CB loading on the morphology of the multiphase blend was also studied using FESEM images. Theoretical models were also used to predict the percolation thresholds for electrical and rheological network formation and compared with the experimental values.