Three-dimensional thermal analysis of heat sinks with circular cooling micro-channels

The pressure drop and thermal characteristics of heat sinks with circular micro-channels are investigated using the continuum model consisting of the conventional Navier-Stokes equations and the energy conservation equation. Developing flow (both hydrodynamically and thermally) is assumed in the fluid region and three-dimensional conjugate heat transfer is assumed in the solid region. Thermal results based on this approach are shown to be in good agreement with existing experimental data. Effects of various geometrical parameters, material properties, and Reynolds number on the thermal performance of the sink were investigated. A comparison between circular and rectangular channels at the same Reynolds number and hydraulic diameter showed that sinks with rectangular channels have lower thermal resistance, while sinks with circular channels dissipate more heat per unit pumping power.     

信息化测绘技术在资源环境发展中的应用

随着时代的进步和技术的发展,中国的测绘技术进入新的发展时期即信息化测绘.主要论述了信息化测绘技术在资源、环境、环保等方面的发展应用.     

Fabrication of three-dimensional nanoporous nickel films with tunable nanoporosity and their excellent electrocatalytic activities for hydrogen evolution reaction

Three-dimensional (3D) nanoporous nickel films were fabricated by a novel and facile method. The fabrication process involved the heat treatment of the electrodeposited zinc layer on nickel substrate and the subsequent electrochemical dealloying. The mutual diffusion of Ni and Zn during the heat treatment resulted in the formation of the Ni₂Zn₁₁ alloy surface film. The 3D nanoporous nickel films with open pores and interconnected ligaments were obtained by the electrochemical dealloying of relatively active zinc from the alloy surface film. As the electrodeposited zinc amount increased, the thickness, pore diameter and pore density of the nanoporous nickel films became larger. In our experimental range, the thickest nanoporous nickel film presented a thickness of 8 μm and an average pore diameter of 700 nm. The as-prepared 3D nanoporous nickel films exhibited much higher electrocatalytic activity for hydrogen evolution reaction (HER) than smooth nickel foil, and their electrocatalytic activities for HER enhanced with increase in the porosity and thickness. It was concluded that the enhanced electrocatalytic activity and excellent electrochemical stability for HER of the as-prepared 3D nanoporous nickel films can be ascribed to their unique nanostructured characteristics.     

RTK技术在黄土塬地震勘探测量中的应用

在对RTK技术进行简要介绍的基础上，叙述了这一技术在黄土塬地区地震勘探测量中的应用，及所取得的良好测量资料。     

在广西全面开展悬移质泥沙简测的可行性和重要性

通过对百色等水文站泥沙资料分析 ,并结合广西河流及泥沙特性和社会对泥沙资料的精度要求 ,得出了在广西实行悬移质泥沙简测的可行性。为满足广西国民经济可持续发展需要 ,提出了在广西改革悬移质泥沙测验方式的必要性和紧迫性     

屯留矿井测量工作必要精度的确定

在生产矿井中所进行的全部测量工作,是指导采矿生产正确、安全和顺利进行的保证。矿井测量工作是否及时,测量精度是否能满足采矿生产的要求,会给矿井生产以直接的影响。因此,必须对矿井测量工作的必要精度进行确定,从而提出正确的测量方案,克服盲目性。     

浅析房地产测量与地形测量的区别

通过对房地产测量和地形测量的区别进行分析,以及对房地产专业知识的诠译,总结出房地产测量的特点,为更好地从事房地产测量工作创造了条件.     

一步测绘法在数字化测图中的应用

对不同类型工程所用大比例尺地形图测绘方法进行了总结,并通过宝鸡陈仓区潘溪河水库加固及施工道路的测绘实例,说明了"一步测绘法"采用一定精度的仪器设备,具有成图速度快,精度满足工程要求,降低测绘成本等优点.可供小区域工程测绘大例尺地形图进行参考.     

自动化立体仓库消防给水设施设计探讨

立体仓库采用智能化出入库管理,集自动入库、智能化储存和自动化出库于一体,物品高度集中,火灾负荷集中的建筑。立体仓库的消防给水设施是其中重要的消防设施之一,本文主要分析立体仓库消防水系统的设计及参数的选择。     

基于MATLAB GUI的色域平台设计与开发

为了实现色域算法一体化集成和数据的可视化分析,基于Matlab GUI设计开发了色域平台,能够完成二维和三维色域数据的处理,且能够实现与用户的交互.实验结果表明,本平台能够较快地处理数据,计算结果较为准确,且操作简单易行,对色域研究工作者提供了很大的方便.