共查询到20条相似文献,搜索用时 734 毫秒
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分析了电加热器对流动氦气的加热过程,从能量平衡和热传导的角度建立了系统数学模型,用解析的方法表达了热量的传递过程,得到了传递函数。用Matlab的Simulink模块搭建了PID的控制框架,用积分分离的策略改进了温度控制的效果。仿真结果显示流体在进口温度不断变化的情况下,通过加热器的功率调节获得了比较稳定的气体出口温度,表现出了良好的控制结果。 相似文献
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众所周知,伊萨克•牛顿(IsaacNewton,1642~1727)是英国伟大的科学家,其研究领域包括了物理学、数学、天文学、自然哲学、炼金术和神学。牛顿发明了微积分,发现了万有引力定律,创建了经典力学,设计并制造了第一架反射式望远镜等,被誉为人类历史上最有影响力的科学家。正如恩格斯所说:"牛顿由于发明了万有引力定律而创立了科学的天文学;由于进行了光的分解,而创立了科学的光学;由于创立了二项式定理和无限理论而创立了科学的数学;由于认识了力的本质,而创立了科学的力学"。假如牛顿生活的时代就有诺贝尔奖的话,他无疑会多次获得诺贝尔奖。为了纪念牛顿的杰出成就,以牛顿的姓氏命名力的单位,国际天文学联合会还把662号小行星命名为牛顿小行星。 相似文献
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用分光计测光栅光谱,实验光源除了普遍用的钠光灯、低压汞灯外,还选用了节能灯,使学生在学习的过程中不仅对常用光源有一定的了解,而且也对其他的光源进行了探索,拓展了学生的知识面,培养了学生的观察能力、创新能力,并且开阔了学生的科学思维,提高了教学质量与效率. 相似文献
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In the last decade there has been an enormous progress in the mathematical understanding of one-dimensional polymer measures, which are path measures that suppress self-intersections. We are currently in the situation that many interesting questions have either been answered, or that essential new ideas are needed. In this survey paper, we discuss the most relevant results, open questions, and heuristics. 相似文献
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A.S. Holevo 《Reports on Mathematical Physics》1977,12(2):273-278
In this paper a survey of some basic concepts of the general communication theory including both classical and quantum case is given. Some open questions are formulated and discussed. 相似文献
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Ulvi Yurtsever 《Foundations of Physics》1983,13(5):529-537
Among the problems C. D. Bailey has questioned in a recent paper (Ref. 1) are a precise and general formulation of Hamilton's variational principle and the establishment of a sufficiency criterion for this to be a minimum principle. In this paper, we will try to answer these questions using the geometric theory of classical mechanics. 相似文献
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激光制导寻的导引头的应用 总被引:4,自引:1,他引:3
综述半主动激光制导武器中导引头的制导原理、发展和现状,着重介绍导引头的结构形式、功能及其特点。针对目前存在的问题,评述导引头今后的发展趋势和方向。 相似文献
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In the studying of fibers microstructure of brain white matter, many reconstruction methods have been proposed to interpret the diffusion-weighted signal. Those methods can be categorized into model-based and model-free methods. In this paper, the diffusion configuration of water molecules are discussed, and two questions are put forward to analyze the performance of the current algorithms about diffusion configuration. The first question is what the diffusion profile looks like in voxel? The second question is what is the location of fibers in a voxel? As a result, firstly, most of model-based algorithms ignore much information coming from the isotropic diffusion, which will lead to an inaccurate estimation. Secondly, model-free algorithms just provide direction information of fibers, ignore or cannot provide location information of fibers. So unfortunately, neither model-based methods nor model-free methods can resolve those two questions very well. How to resolve those questions is still an open problem, and it may be an interesting direction in the future research. 相似文献
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Jae-Kwan Shim 《Journal of Geometry and Physics》2003,44(4):475-480
In this paper, we address one of the questions raised by Rieffel in his collection of questions on deformation quantization. The question is whether the K-theory groups remain the same under flabby strict deformation quantizations. By “deforming” the question slightly, we produce a negative answer to the question. 相似文献
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We consider the problem of super-resolution reconstruction (SRR) in MRI. Subpixel-shifted MR images were taken in several fields of view (FOVs) to reconstruct a high-resolution image. A novel algorithm is presented. The algorithm can be applied locally and guarantees perfect reconstruction in the absence of noise. Results that demonstrate resolution improvement are given for phantom studies (mathematical model) as well as for MRI studies of a phantom carried out with a GE clinical scanner. The method raises questions that are discussed in the last section of the paper. Open questions should be answered in order to apply this method for clinical purposes. 相似文献