排序方式： 共有151条查询结果，搜索用时 15 毫秒
71.
田宝忠 《天津职业院校联合学报》2010,12(2):76-77,80
在匀速转动参照系下,当某一理想流体作定常流动时,选取一个任意形状流管,可以推导出其伯努利方程式：1/2ρv^2＋ρ（gy-1/2x^2ω^2）＋P=常数,利用该方程可以简便地处理流体匀速转动问题。 相似文献
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DYAKOWSKI Tom 《浙江大学学报(A卷英文版)》2005,6(12):1374-1378
INTRODUCTION In recent years, developments in the technology have led to widespread use of electrical tomography for industrial applications. Electrical tomography i based on the use of an array of the sensors located along the pipe axis or the reactor circumference Images obtained from electrical tomography show th cross-sectional spatial variation of dielectric constan or resistivity. With proper calibration these image depict the distribution of phase density or phas concentration in t… 相似文献
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Conclusions The putt-putt boat’s operation has two phases, ejection and suction. During ejection water is thrown out of the pipes, and
dur-ing suction an equal quantity of water is injested. Even though the net mass flow is zero, the differences in the flow
patterns during outflow and inflow cause a net forward thrust; thrust is mainly produced during ejection phase.
Neglecting the suction part of the cycle for dynamic analysis of the boat agrees quite well with the experimental data obtained.
Moreover, modeling the boat as a kayak, rather than a flat plate gives a better drag estimate. The diaphragm just makes the
puttputt sound and is not involved in the propulsion.
In the second part, the thermodynamic process involved in generating the thrust and drag forces will be dealt with. 相似文献
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通过对工程流体力学的教学现状进行分析,从以工程案例为导向开展教学、注重开展实验教学活动、灵活采用丰富的教学方式、充分发挥在线教学平台的优势、建立起全面的成绩考核机制等方面,提出了推进工程流体力学教学改革的具体建议。 相似文献
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研究目的：求斛双圆盘转了-密封系统的非线性振动特性和运动响应 创新要点：采用有限元法（FEM）和拉格朗目方程求解双圆盘转子-密封系统,进而为研究多级转了系统的非线性振动问题提供有效方法。研究方法：基于有限元法（FEM）和拉格朗目方程。同时利用四阶龙格-库塔法求解系统动特性运动响应情况,利用风岔图、时间历程图、轴心轨迹图、庞加莱映射和幅值谱等分析图研究双圆盘转子-密封系统的非线性振动特性。重要结论：随着转速的增大,双圆盘转子-密封系统呈现丰富的非线性运动形式,包括周期性运动、多周期运动,准周期运动以及混沌运动。在右端圆盘不平衡质量小于34kg、密封间隙范围为0.376mm-0.54mm、密封长度大于0.13m或者密封压差高于0.104MPa的情况下均有利于提高双圆盘转子-密封系统的稳定性。 相似文献
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《流体输配管网》是建筑环境与设备工程专业的重要核心课程,为改进教学方法,总结归纳了作者多年的教学经验,形成了基本设计法,指出了教学的关键是构建系统的理论构架和知识的应用,提出了工程案例教学法。同时,教材和实验室建设也是该课程教学重要的内容。 相似文献
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Using a sample of 171 children, we examined classroom quality as a potential moderator of the link between three distinct but related aspects of cognition (fluid intelligence, crystallized intelligence, and executive functioning) and math achievement across the kindergarten year. Multilevel modeling analyses were conducted to account for nesting of students within classrooms. Results revealed significant aptitude by treatment interactions for fluid and crystallized intelligence, suggesting that classroom practices may affect children differently depending on their abilities. Children with higher levels of fluid intelligence and of crystallized intelligence fared better in higher quality classrooms. Results also provide some support for Cattell's investment hypothesis. Implications of the results are discussed. 相似文献
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由于工业上大量应用了三通管,确定三通管后的温度对于定位三通管后的附件和仪表有非常重要的指导意义。本文定性分析了三通混合后的混合特性,并给出一般性结论。 相似文献
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研究了紫外可见分光光度计在301.7nm处测定铜及铜合金抛光液中硝酸根的浓度。方法的线性范围为0.9662—9.6621g/L,适合于该类型抛光液中硝酸根的检测。该方法快速简便、准确度高、精密度好。 相似文献
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