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消失模铸造借用型腔作浇道研究 被引量:3
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作者 刘立中 《铸造技术》 CAS 2019年第9期985-988,共4页
为了减少消失模铸造浇注过程金属液带人的热量损失,简化浇注系统是有效措施之一。铸钢件排碳法浇注工艺,钢液从冒口注入,从形式上而言,无浇注系统,实际上是将型腔作为浇注系统,是借用型腔作浇道。结果表明,借用型腔作浇道,浇口从冒口或... 为了减少消失模铸造浇注过程金属液带人的热量损失,简化浇注系统是有效措施之一。铸钢件排碳法浇注工艺,钢液从冒口注入,从形式上而言,无浇注系统,实际上是将型腔作为浇注系统,是借用型腔作浇道。结果表明,借用型腔作浇道,浇口从冒口或铸件的顶部直接引入实现了顶注优先工艺。金属液进入型腔后,直接落底,然后液面水平上升,实现铸件下部温度低,顶部温度高的正向热场。这是消失模铸造值得研究和推荐的工艺。 展开更多
关键词 消失模铸造 三场理论 借用型腔作浇道
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基于三场协同原理的动力机车电池冷却冷板结构优化研究
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作者 石达 李冬 +3 位作者 张延蕾 阎凯 张凯 何雅玲 《工程热物理学报》 EI CSCD 北大核心 2023年第10期2818-2825,共8页
本文以某型动力机车电池冷却冷板为研究对象,利用数值仿真方法对其换热性能进行了分析研究,发现该冷板的回环式流道长度过长,冷板中部区域流体温差较小,不足以使该区域温度降低,整体换热性能较差。基于三场协同理论,提出了互联折返式和... 本文以某型动力机车电池冷却冷板为研究对象,利用数值仿真方法对其换热性能进行了分析研究,发现该冷板的回环式流道长度过长,冷板中部区域流体温差较小,不足以使该区域温度降低,整体换热性能较差。基于三场协同理论,提出了互联折返式和“W”型间断流道两种新型冷板结构,计算结果表明两种新型结构可有效提升冷板换热性能,受热面平均温度最高下降近6 K,所提出的新型冷板结构可为动力机车电池冷却系统冷板设计提供参考和指导。 展开更多
关键词 动力机车电池冷却 冷板 协同理论 结构优化
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Uniqueness of First Order Post-Newtonian Collinear Solutions for Three-Body Problem under a Scalar-Tensor Theory
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作者 曹伟光 周天倚 谢懿 《Communications in Theoretical Physics》 SCIE CAS CSCD 2017年第10期455-462,共8页
As a continuing investigation of an earlier work that establishes the cofiinear solutions to the three-body problem with general masses under a scalar-tensor theory, we study these solutions and prove their uniqueness... As a continuing investigation of an earlier work that establishes the cofiinear solutions to the three-body problem with general masses under a scalar-tensor theory, we study these solutions and prove their uniqueness up to the first order post-Newtonian approximation. With the help of observed bounds on the scalar field in the Solar System, we show that the seventh-order polynomial equation determining the distance ratio among the three masses has either one or three positive roots. However, in the case with three positive roots, it is found that two positive roots break down the slow-motion condition for the post-Newtonian approximation so that only one positive root is physically valid. The resulting uniqueness suggests that the locations of the three masses are very close to their Newtonian positions with post-Newtonian corrections of general relativity and the scalar field. We also prove that, in the framework of the scalar-tensor theory, the angular velocity of the collinear configuration is always less than the Newtonian one when all other parameters are fixed. These results are valid only for three-body systems where upper-bounds on the scalar field are compatible with those of the Solar System. 展开更多
关键词 scalar-tensor theory THREE-BODY
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