Towards an understanding of the behavioral intention to use 3G mobile value-added services

As profit margins gradually decline, and market competition becomes increasingly intensive, 3G telecom operators must provide various mobile value-added services, as well as traditional voice services, to attract new subscribers and retain old ones. However, for many 3G mobile value-added services, whether ARPU (average revenue per user) can be effectively enhanced depends on the consumer behavioral intentions. Therefore, this study uses the Technology Acceptance Model as the foundation and incorporate personal innovativeness and perceived cost to further understand consumer’s behavioral intention to use 3G mobile value-added services. The following conclusions can be reached from the research findings: (1) consumer usage rate of current 3G value-added services remains low; (2) increased personal innovativeness will directly enhance the perceived ease of use of 3G mobile value-added services; (3) the perceived usefulness is enhanced when consumers perceive higher ease of use of value-added services; (4) perceived usefulness has the strongest effect on consumer attitude, followed by perceived ease of use and perceived cost, and (5) the most important factor in increasing consumer’s behavioral intention to use 3G mobile value-added services is attitude, followed by perceived ease of use, perceived cost and perceived usefulness. Results of this study provide a valuable reference for service providers to develop mobile value-added services.     

Fuzzy Sliding Mode Control for the Vehicle Height and Leveling Adjustment System of an Electronic Air Suspension

The accurate control for the vehicle height and leveling adjustment system of an electronic air suspension(EAS) still is a challenging problem that has not been effectively solved in prior researches. This paper proposes a new adaptive controller to control the vehicle height and to adjust the roll and pitch angles of the vehicle body(leveling control) during the vehicle height adjustment procedures by an EAS system. A nonlinear mechanism model of the full?car vehicle height adjustment system is established to reflect the system dynamic behaviors and to derive the system optimal control law. To deal with the nonlinear characters in the vehicle height and leveling adjustment processes, the nonlinear system model is globally linearized through the state feedback method. On this basis, a fuzzy sliding mode controller(FSMC) is designed to improve the control accuracy of the vehicle height adjustment and to reduce the peak values of the roll and pitch angles of the vehicle body. To verify the effectiveness of the proposed control method more accurately, the full?car EAS system model programmed using AMESim is also given. Then, the co?simulation study of the FSMC performance can be conducted. Finally, actual vehicle tests are performed with a city bus, and the test results illustrate that the vehicle height adjustment performance is effectively guaranteed by the FSMC, and the peak values of the roll and pitch angles of the vehicle body during the vehicle height adjustment procedures are also reduced significantly. This research proposes an effective control methodology for the vehicle height and leveling adjustment system of an EAS, which provides a favorable control performance for the system.     

声桥系统压电植入振子力学建模及参数优化

根据作用于圆窗的压电式振动声桥的工作原理,建立了压电振子与圆窗耦合的动力学模型,由此推导出该模型的电-机能量转化的传递函数.通过在Matlab环境中进行仿真试验,讨论了压电应变常数、振子支座质量及支座刚度等参数对传递函数的影响,并分别优化了各个参数.研究结果为新型振动压电植入振子的研制奠定了理论基础.     

气体钻井椭圆井眼应力分布规律研究

利用复变函数方法对椭圆井眼井壁附近岩石的应力分布模型进行求解,研究了气体钻井条件下椭圆
井眼的扩径机理。结果表明,在气体钻井过程中椭圆井眼井壁岩石受到周向应力影响较大,受到的径向应力和切
向应力影响较小。在最小水平主应力方向上椭圆井眼附近岩石受到的周向应力最大,径向应力最小;在最大水平
主应力方向上椭圆井眼附近岩石受到的周向应力最小,并且井眼附近岩石受到的切向应力状态发生改变,由压缩
状态变为拉伸状态;径向应力在井眼一定范围内保持最大值。此外,随着椭圆长短轴之比变大,最小水平主应力方
向上椭圆井壁处的周向应力快速变大,井壁处应力集中加剧,最大水平主应力方向上周向应力快速变小,井壁处应
力集中减弱。     

汽提塔顶冷却器浮头螺栓失效分析

通过对某炼油厂汽提塔顶冷却器已断裂的浮头螺栓进行化学成分分析，金相（裂纹）分析，断口分析，腐蚀产物X衍射分析试验，硬度测试等试验研究工作，讨论了导致浮头螺栓断裂的主要原因，并提出相应的预防建议。     

Morphology control of cathodically deposited TiO2 films

This work demonstrates that the microstructure of TiO₂ film can be designed and controlled by adjusting the temperature and cycle number of cathodic deposition in a solution containing TiCl₃ and NaNO₃. The redox interactions between TiCl₃ and NO₃⁻ are investigated by in situ ultraviolet-visible (UV-vis) absorption spectroscopy. Linear sweep voltammetry (LSV) is employed to study the NO₃⁻ reduction and to clarify the deposition behavior of TiO₂ in the designed plating solution. The decrease in TiO₂ deposition rate with the TiO₂ thickness may be due to the poor electron conductivity of TiO₂ depressing the generation rate of OH⁻ from the NO₃⁻ reduction. The morphology and size of TiO₂ aggregates are strongly influenced by varying the deposition temperature from 5 to 50 °C and a maximal rate of TiO₂ deposition is obtained at 25-35 °C. TiO₂ deposited at 25 °C is the roughest with a roughness factor (Ra) of ca. 67 nm. This study provides a useful method to control the morphology and deposition rate of TiO₂ film for practical photoelectrochemical applications.     

Carrier Transport Mechanism and Band Offsets at the Interface of ZnS/<Emphasis Type="Italic">n</Emphasis>-Si (111) Heterojunctions Fabricated by Vacuum Thermal Evaporation

The electrical properties and band offset of ZnS/n-Si(111) heterojunctions with and without annealing were analyzed. The result showed that the rectifying characteristics of ZnS/n-Si(111) heterojunctions became better and the leakage current increased after annealing. This phenomenon is mostly due to the volatilization of S atoms of ZnS films and leads to defect levels appearing at the interface of the ZnS/n-Si(111) hetrojunctions. The valence band offset (ΔE _V) of the ZnS/n-Si(111) heterojunctions can be calculated to be ?0.7 ± 0.15 eV by means of photoelectron spectroscopy, indicating that the band offsets of ZnS/n-Si(111) heterojunctions show a type-II band alignment.     

基于栅控二极管研究碲镉汞器件表面效应

采用不同工艺生长了CdTe/ZnS复合钝化层,制备了相应的长波HgCdTe栅控二极管器件并进行了不同条件下I-V测试分析.结果表明,标准工艺制备的器件界面存在较高面密度极性为正的固定电荷,在较高的反偏下形成较大的表面沟道漏电流,对器件性能具有重要的影响.通过钝化膜生长工艺的改进有效减小了器件界面固定电荷面密度,使HgCdTe表面从弱反型状态逐渐向平带状态转变,表面效应得到有效抑制,器件反向特性获得显著改善.此外,基于最优的工艺条件制备的器件界面态陷阱数量得到大幅降低,器件稳定性增强;同时器件R_0A随栅压未发生明显地变化.     

活塞销清洁度超差原因探讨

本文重点介绍了影响活塞销产品清洁度的几个重要方面，为解决清洁度超差、满足顾客要求找到了一个途径。