Determination of the embedded electronic states at nanoscale interface via surface-sensitive photoemission spectroscopy

The fabrication of small-scale electronics usually involves the integration of different functional materials. The electronic states at the nanoscale interface ...     

Molecular dynamics study on nanotube-resonators with mass migration applicable to both frequency-tuner and data-storage-media

We investigated the cantilevered carbon-nanotube-resonator including electromigratively movable nanoparticle via classical molecular dynamics simulations and continuum model. The change of the effective mass value, which was closely correlated with the position change of the encapsulated nanoparticle, could be regressed by a power function, the resonance frequency of the carbon-nanotube-resonator could be tuned by controlling the nanoparticle’s position, and the possible frequency-shift-ranges then reached 18–85%. The suggested device could be served as a data-storage-media for electromechanical nonvolatile-memory as well as a frequency-tuner.     

Degenerate problems of optimal control. II

The paper is the second part of the review of the results obtained by the special theory of the degenerate problems of optimal control and its applications, including the newest ones. Consideration was given to the methods based on the rearrangement of the degenerate problems in the smaller-order regular derivative problems, the main types of solutions of the derivative problems, and the issues of their realization as the generalized solutions of the original problems. The generalized conditions for their optimality were derived. Examples, both methodological and applied, were presented to demonstrate the efficiency of these methods.     

Tooling device design for vibration-assisted high speed shaping of PMMA

PMMA optical components that are used as one of the most important parts of high precision equipments and machines are increasingly replacing the glass due to the various advantages of PMMA. Especially in Light Guide Panels, the PMMA sheet that is used in Liquid Crystal Displays plays an important role in scattering the incident light and requires very fine machining as the sheet is directly related to the optical characteristics of the panels. The High Speed End milling and High Speed Shaping processes that are widely adopted and applied to the precise machining of Light Incident Plane still have quality problems, such as cracks, breakages, poor waviness, and straightness. This paper presents the tooling device design for machining a Light Incident Plane through vibration-assisted High Speed Shaping for increasing the optical quality by minimizing the above-mentioned problems. The cutting tool and the tool post presented in this paper are designed by the authors to increase the magnitude of the cutting stroke by adopting the resonant frequency without weakening the stiffness and to reduce vibrations during even high speed feeding. The dynamic characteristics of the cutting tool and the tool post are evaluated through simulation and experiment as well. The results reveal very appropriate dynamic characteristics for vibration-assisted High Speed Shaping.     

A study on tension behavior considering thermal effects in roll-to-roll E-printing

The mathematical model for tension in a moving web by Shin [1] was extended by considering thermal strain due to temperature fluctuations in the drying of a roll-to-roll system. The extended model describes variations in tension and includes terms that represent the change of the Young’s Modulus, the thermal coefficient, and the thermal strain. In this paper, a new control scheme based on the extended model is proposed for mitigation of tension disturbances due to thermal strain in the drying process. Tension feedback control logic generally is not be applied due to the fact that register errors can be induced by speed alterations that help to compensate for tension disturbances. But in our approach, the thermal strain in the web is compensated for by means of velocity adjustments without adding extra register errors in the steady state. A computer simulation followed by an experimental validation was carried out to confirm the performance of the proposed method. The results show that the proposed model is useful for describing tension behavior and suggest that tension control logic improves control precision for the drying module of a roll-to-roll e-printing system.     

精英荟萃,深度交流,推进煤矿瓦斯综合治理与利用——记“2010年中国煤矿瓦斯治理国际研讨会”

初夏的安徽省城合肥,气候宜人、绿色醉人.在习习和风的吹拂下,市树广玉兰张开婀娜的花瓣迎接着参加2010中国煤矿瓦斯治理国际研讨会的中外客人.5月29日,来自世界各地约350名中外代表在热情周到的志愿者的带领下步入安徽省合肥市政府小礼堂,参加国际煤矿瓦斯治理领域级别最高的一次会议--2010中国煤矿瓦斯治理国际研讨会.     

A physics-based simulation approach for cooperative erection activities

Cooperative erection activities are critical to projects which involve the erection of heavy loads or the installation of special equipment. Detailed simulation on computer prior to construction can identify constructability problems, and subsequently avoided during actual erections. This paper describes an integrated approach for simulating the detailed motions of cranes. This research develops a physics-based model that follows the principle of closed-form forward kinematics and constraint-based dynamics to present the dual-crane mechanism mathematically — a non-trivial task. This model can be used to analyze the inputs from the users (i.e. virtual crane operators) and simultaneously compute the cables sway and reaction of collisions. We also implemented the model on computer and developed a simulation system, Erection Director, to render realistic cooperative erection activities. A demonstration of simulating two-crane lift has been built and three performance tests including a small building (840 elements), a medium building (1937 elements) and a large building (2682 elements) validate the feasibility of the proposed approach. The test results indicate that Erection Director can support real-time and physics-based visualization of cooperative erections.     

大规模风电接入对江苏电网安全稳定性的影响

大规模风电接入后对江苏电网的安全稳定运行带来了挑战,有必要分析研究大规模风电接入后对江苏电网安全稳定性的影响。基于江苏电网和风电2015年的规划数据,分析研究不同风电接入比例下,江苏电网断面潮流和枢纽节点电压的变化及其对电压稳定性的影响;根据潮流计算和N-1校验的结果,分析电网内重载线路故障时的极限切除时间,考核电网的暂态稳定性。针对大规模风电并网后,江苏电网存在的安全稳定隐患提出了相关的改善措施。     

基于内模原理的自适应电流检测系统研究

传统自适应电流检测方法因受到低信噪比检测环境引起的交互式误差干扰的严重影响,难以兼顾检测方法的快速性和精确性。本文提出了一种新颖的自适应电流检测方法,引入滑动积分滤波器(SIF)消除谐波电流的干扰,并获取基波有功、无功电流幅值估算误差。基于内模控制原理构成有功、无功电流的自适应检测闭环系统,快速、准确地分离提取畸变负载电流中的目标电流分量。文中对所提出的自适应电流检测方法建立了数学模型,并基于控制理论中的方法对本文电流检测方法的收敛性及其快速性、精确性进行了理论分析,为自适应电流检测方法的性能设计提供了理论指导。最后,通过仿真和实验证明本文所提出理论和方法的正确性与有效性。