共查询到20条相似文献,搜索用时 62 毫秒
1.
微小器件热特性具有快速产生、不可逆、易损坏器件等性质,较难在瞬间捕捉到它变化的一些信息.为了研究微小器件热特性,本文引入了一种测试器件热性能的新方法——反射率热成像法,并对该种方法的成像原理、功能应用作了简单介绍.在实际测试小器件热特性过程中,应用反射率热成像系统与红外热像仪进行了对比测试,结果表明:反射率热成像系统空间分辨率更高,达到亚微米量级;时间分辨率更高,达到百纳秒级;对样品温度要求低,温度范围更大,不需要对样品加热;只需对新材料进行校准,无需对样品表面进行逐点校准.在要求高分辨率、超快速的微小尺寸热测试领域,反射率热成像仪有着很好的应用前景. 相似文献
2.
3.
《中国新技术新产品》2017,(19)
现在人们对于供电企业的供电安全稳定性提出了较高的要求,所以供电企业为了最大限度地满足人们生产生活的实际需求,尽可能地减少停电对大家造成的不变影响,所以经常会对电力设备进行带电检修的操作,在这一过程中,借助红外热成像技术就可以实现对电力设备的带电检修操作,借助该技术可以很好地检测出电力设备内部的绝缘介质温度高低,以及电力设备在实际运行中是否存在问题故障,或是设备缺陷等,对于发现的问题可以采取及时的修正措施,避免造成对电力设备运行稳定性的更大影响,维护设备的正常运转,为用户提供可靠安全的供电需求。本文就次展开论述,仅供参考。 相似文献
4.
5.
采用红外热成像技术研究了聚酯(PET)纤维的冷拉颈缩现象,选用一种特殊的18μm微焦镜头,形变过程中纤维的温度和直径变化能被同时检测到。红外热像图显示冷拉生热温度变化仅发生在纤维成颈区域,而且随着拉伸速率的提高,成颈区域温度升高可超过环境温度50℃~85℃。通过热力学的方法分析形变过程内能的变化,结果发现,内能随着拉伸不断减小,显示PET纤维在形变过程引发诱导结晶。 相似文献
6.
[摘要]随着时代的发展,电网规模迅猛增长,社会对供电可靠性的要求越来越高,同时一些新型设备在电网中开始使用,一些新的检修试验方法得到推广应用。红外热成像技术具有技术先进实用性强,普查效率高,检测灵敏度可靠,不停电,安全性好等特点,而成为输变电设备状态检修的一项重要内容,成为电力系统管理和检修的主要手段和方法。本文主要采用红外热成像技术分析运行设备热故障,同时对工作中存在的各种问题加以总结和探索。 相似文献
7.
高炉炉顶红外成像监测系统是有效监控高炉内部运转情况的设备,对高炉上部环境进行监控,能全面地了解高炉内部空间的物料环境、气流情况和布料情况等,对于整个工业生产过程有着较大意义。本文以实际案例分析了高炉炉顶热成像存在的问题,并在此基础上对其进行热成像的系统改造,有效地解决了炉顶红外热成像系统技术性问题,并提出一系列的安全防护措施,以期为我国高炉炉顶红外热成像系统使用能力的快速提升带来更多经验参考。 相似文献
8.
9.
目的采用红外热成像系统对压印接触区域橡皮布的动态应变进行测试。方法建立压印接触区域几何模型,结合热弹性效应与热辐射理论分析温度与应变之间的函数关系,并采用红外热像系统测得压印接触区域橡皮布的温度分布情况,最后通过有限元仿真得到橡皮布压痕处的应变云图。结果沿轴线方向,压印接触区域橡皮布温度、应变均呈不均匀分布,轴端温度高于中间区域温度;轴端应力集中,节点位移大,变形量大,中间区域节点位移小,变形量小,中间区域应变量低于轴端区域应变量。结论采用红外热成像技术测试印刷过程中橡皮布动态应变的方法是可行的。 相似文献
10.
11.
针对多孔夹层圆柱壳的主动散热性能以及等效热导率的计算问题,通过推导多孔结构的等效热导率和主动散热状态下的稳态温度控制方程,在对流换热条件下,计算了考虑主动散热后所折减的等效热导率,及其与结构相对密度和流体流速之间的关系。采用考虑主动散热的等效热导率,计算结构瞬态温度分布,并与有限元结果进行对比。同时,计算了夹层圆柱壳相对密度和结构散热性能的关系以及最大散热性能相对应的最优相对密度和最优杆件厚度。通过瞬态温度分布结果与有限元结果对比,得到采用考虑主动散热的等效热导率所得结果与有限元结果吻合,说明了计算等效热导率方法的有效性,并且可以准确地计算瞬态温度分布;同时分析得到等效热导率随着流体流速的增大而减小,随着结构相对密度的增大而增大;在相同结构质量下,正方形和正六边形构型具有较好的主动散热性能。 相似文献
12.
13.
Abstract Functional analytic methods have been applied to the analysis of the extended Graetz problem with prescribed wall flux and viscous dissipation between parallel plates. First, the non‐self‐adjoint elliptic energy equation is decomposed into a set of first order partial differential equations to obtain a self‐adjoint formulism. Next, the induced eigenvalue problems are solved by applying an approximation method in a Hilbert space, and an algebraic characteristic equation is obtained. In addition, the expansion coefficients of the solutions on upstream and downstream regions can be explicitly obtained and unnecessary to match at the entrance. 相似文献
14.
Bo Zhou Yin Luo Mei Yang Baoguo Chen Mingchang Wang Li Peng 《Journal of Modern Optics》2019,66(1):33-46
Detail enhancement algorithms are important for raw infrared images to improve their overall contrast and highlight important information in them. To solve the problems that current algorithms like GF&DDE have, an improved adaptive detail enhancement algorithm for infrared images based on a guided image filter is proposed in this paper. It chooses the threshold for the base layer image adaptively according to the histogram statistical information and adjusts the mapping range of the histograms according to the dynamic range of the image. Besides, the detail layer is handled by a simpler adaptive gain control method to achieve the good detail enhancement effect. Finally, the base layer and the detail are merged according to the approximate proportion of the background and the details. Experimental results show that the proposed algorithm can adaptively and efficiently enhance different dynamic range images in different scenarios. Moreover, this algorithm has high real-time performance. 相似文献
15.
Jie Zhang 《International journal for numerical methods in engineering》2020,121(1):54-92
A comprehensive study of A-stable linear two-step time integration methods for structural dynamics analysis is presented in this paper. An optimal A-stable linear two-step (OALTS) time integration method is revealed with desirable performance on low-frequency accuracy and high-frequency numerical dissipation properties. The OALTS time integration method is implemented in a direct integration manner for the second-order equations of structural dynamics; is implicit, A-stable, and second-order accurate in displacement, velocity, and acceleration, simultaneously; is easily started; and is numerical dissipation controllable. The OALTS time integration method shows desirable performance on spectral radius distribution, dissipation and dispersion errors, and overshooting behavior, where the results of some typical algorithms in the literature are also compared. Benchmark examples with/without physical damping are performed to validate the accuracy, stability, and efficiency of the OALTS time integration method. 相似文献
16.
低温下导热系数测定对生物器官的低温保存、低温外科医学及数值模拟计算至关重要.在分析探针法测量原理的基础上,用探针法对低温下猪主动脉的导热系数进行了测量研究.实验表明探针在用甘油和蒸馏水进行标定后,可以方便准确地测量-90~-35℃温区下猪主动脉的导热系数. 相似文献
17.
A new family of unconditionally stable integration methods for structural dynamics has been developed, which possesses the favorable numerical dissipation properties that can be continuously controlled. In particular, it can have zero damping. This numerical damping is helpful to suppress or even eliminate the spurious participation of high frequency modes, whereas the low frequency modes are almost unaffected. The most important improvement of this family method is that it involves no nonlinear iterations for each time step, and thus it is very computationally efficient when compared with a general second‐order accurate integration method, such as the constant average acceleration method. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
18.
Abstract A solution of the extended Graetz problem with prescribed wall heat flux and viscous dissipation in a semi‐infinite axial region of a tube is obtained by functional analytic methods. The energy equation is split into a set of partial differential equations to obtain a self‐adjoint formulism. Then, an algebraic characteristic equation of the eigenvalue problem for an arbitrary velocity profile is obtained by an approximation method in L 2[0, 1]. In addition, a backward recursive formula for calculating the expansion coefficients of the solution is developed. 相似文献
19.
20.
通过推导2种不同换热边界条件下平板夹层多孔材料的散热指标, 研究了考虑对流换热因素的平板夹层多孔材料主动散热性能, 得到了影响材料散热性能的因素。分析了在确定的相对厚度下, 不同构型多孔材料的相对密度与散热指标的关系, 并得出正六边形构型的散热指数最大。随着相对厚度的增大, 最大散热指标和最优相对密度增大较快, 当相对厚度大于20时, 最大散热指标和最优相对密度变化较小并最终趋于定值。由上述结果可以得到相对应的最小质量, 随着最小质量的增大, 最大散热指标增大并最终趋于定值。在相同的最大散热指标下, 随着表面换热系数比值的增大, 最小质量逐渐减小。最后考虑承载因素对结构进行了优化分析, 正六边形构型的多孔材料具有明显的综合性能优势。 相似文献