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101.
刚性圆板自由落体在水面上的冲击压力 总被引:2,自引:0,他引:2
本文对一个刚性圆板自由落体在水面上的冲击过程建立了比较精确的理论模型,并建立了相应的数值格式。计算结果与已有的实验结果符合良好,通过计算进一步给出了下落质量和下落高度对冲击压力峰值的影响。 相似文献
102.
Conducted 2 laboratory experiments with 117 undergraduates to examine (1) the effect of assigned goal difficulty on arousal (self-report and heart rate), cognition (perceived norm, self-efficacy strength, and personal goal), and behavioral (task performance) measures and (2) the role of heart rate as a mediator of the goal-difficulty–performance relation. All Ss performed a task requiring cognitive and physical responses. Results of both experiments demonstrate that assigned goal difficulty affected heart rate, cognition, and task performance and that heart rate change was positively related to the cognitive and behavioral measures. Regression analyses suggested that a cognitive–affective mechanism may mediate the goal-difficulty–performance relation. Discussion is focused on the theoretical and practical implications of integrating an arousal concept within goal-setting theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
103.
结合西气东输管道工程燃气轮机驱动压缩机组设备订货及验收中对性能试验项目的确定、工厂试验及见证过程,介绍了燃压机组性能试验项目所涉及的主要内容、执行标准、需要达到的技术指标,各种性能试验的基本情况,买方参加工厂试验见证中需要重点处理好的问题等。以期为我国其他大型长输天然气管道机组订货及试验见证工作提供借鉴。 相似文献
104.
An observer-based robust adaptive nonlinear position and speed tracking controller is developed for a permanent magnet synchronous motor with initial rotor angle uncertainty. The unknown initial rotor position is treated as a constant motor parameter in the development of the controller. An incremental encoder, which provides relative position variation of the rotor, is used along with stator current signals to achieve stable control. However, the controller does not require the knowledge of motor parameters and it only assumes friction, external disturbances, and model uncertainties are bounded. By using state observers, the measurement of acceleration and load torque, which is required usually in the nonlinear controller design with high tracking performance, is avoided. The stability of the control system and tracking convergence are guaranteed using Lyapunov theory. Finally, the stability and efficacy of the proposed drive system are verified by experimental results. 相似文献
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The public information signs ( The term public information signs will be abbreviated to public signs in the following text.)in the urban areas not only offer convenience for people to move around, but also reflect the level of development and progress of those areas. It is essential to the creative development and uplifting of the New Costal Area (thereafter, NCA) to have a good understanding of its present situation with regard to its public signs, to discuss the related issues in the development, to work out a system that is up to international standard and develop its own standards in the course of implementing the national strategies on standardizing public signs. 相似文献
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108.
水平管路清管过程流动参数变化规律模拟研究 总被引:4,自引:0,他引:4
混输管路清管技术的研究对混输管道的运行管理具有非常重要的意义。在分析清管器清管物理模型的基础上 ,建立清管器的特征参数计算模型、动态数学模型和数值计算方法 ,并进行数值模拟 ,计算出测压点压力随时间变化的数据 ,并把它们与试验数据进行比较 ,得到清管过程中压力的变化规律。通过数学模拟 ,可以计算清管过程中管道的压力分布状况 ,利用压力分布状况就可跟踪清管球在管道内的运行情况 相似文献
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110.
Lowe Rob; Bennett Paul; Walker Ian; Milne Sarah; Bozionelos George 《Canadian Metallurgical Quarterly》2003,22(5):464
The theory of planned behavior suggests attitudes are a product of salient beliefs. This study examined whether aggregating salient beliefs was plausible within a more biologically centered information-processing environment. A neural network was used to examine associations among beliefs relating to exercise intention. Data on intentions and behavioral, normative, and control beliefs from 114 respondents were used to train (by error backpropagation) a neural network to associate beliefs with intention. The R2 between the network's estimated and self-reported intention was .66. The network's representation comprised 6 belief profiles associated with high, moderate, or low behavioral intention. The neural network accommodated complex relationships among beliefs and belief-intention associations and indicated how high-level constructs such as attitudes may be viewed as the best fit (compromise state) between aroused beliefs. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献