液晶显示驱动电路中Fibonacci型电荷泵单元

本文中所设计的电荷泵将用于手机液晶显示驱动模块中.通过对Fibonacci型电荷泵上升时间的估算,对减小上升时间和动态功耗进行折中考虑,本文提出优化开关频率的方法.用1.2μm CMOS双阱工艺参数对所设计的电荷泵进行模拟,结果表明这个电荷泵具有较快的上升速度和较高的效率.通过提高V_GS电平和保证开关管的衬底始终接在最高电位上,文中提出了一种新型Fibonacci电荷泵,它可以正常工作在从1.2V到5V变化的多种电源电压下.     

罗茨真空泵机组抽气速率分析

罗茨真空泵机组因配用前级泵不同和所处工作压力范围的差异，相应其抽气速率变化较大，设计中应根据具体工况条件及真空系统使用要求，力求使罗茨真空泵机组体现好的适用性和经济性。     

螺旋槽管强化传热原理及在石化装置上的应用前景

详细介绍了螺旋槽管换热器的强化传热原理 ,阐明了在无相变和有相变两种工况下 ,螺旋槽管换热器的强化作用 ,并介绍了螺旋槽管换热器的设计计算方法。说明了在石油化工装置上应用的必要性     

双跨换热器传热管在静水中阻尼特性的研究

本文对双跨换热器传热管在静水中的结构阻尼与粘滞阻尼作了简介,并对在总阻尼中占主导地位的挤压膜阻尼作了较深入的讨论。Mulcahy 于80年代初提出的挤压膜阻尼数学模型是较为完善的,其缺陷是未计入管子振幅的影响,本文对它进行了修正。为了验证理论分析的结果,笔者对双跨传热管在静水中的挤压膜阻尼作了实验研究,得出挤压膜阻尼与中间支承板厚度、管子-中间支承板间隙以及管子振幅之间的关系。     

电潜泵中压变频调速系统的改进

电潜泵中压变频器输出端产生高次谐波和脉冲电流 ,对电潜泵电动机的绝缘性能和轴承寿命造成不利影响。为此 ,提出 3项改进对策 :①采用谐振软性开关逆变电路 ,使功率开关器件在零电压条件下导通 ;②在变频器逆变输出端设置电抗滤波器抑制高次谐波电流 ;③改变电动机内部结构 ,如加大定子槽宽 ,增加转子导条尺寸 ,变星接法为星 角接法 ,采用绝缘轴承等。实践证明 ,采取改进对策后 ,不仅提高了电潜泵的产量 ,而且变频器滤波后电动机端的过电压明显减小 ,电潜泵和电缆的寿命延长     

测距仪中新型的脉冲激光光源

针对现有测距仪中脉冲激光器存在寄生多脉冲的问题，提出并实现新型的采用同步泵浦声光调Q方法的测距仪用激光器、消除了寄生脉冲并提高了激光器的峰值功率。     

地源热泵——辐射地板联供试验

通过地源热泵－辐射地板系统冬夏联供试验，讨论了该系统作为新型环保节能空调方式的可行性及优越性，并对运行中出现的问题进行分析。     

The Clausius inequality corrected for heat transfer involving radiation

The objective of this paper is to prove that the Clausius inequality must be re-stated to have general applicability for heat transfer involving radiative fluxes. The integrand (đQ/T) of the Clausius expression applies to heat conduction and convection, but does not hold for most radiative transfer scenarios, with the exception of reversible infinitesimal net blackbody radiation transfer. In other cases involving radiative transfer, the equality holds for a cycle even though irreversible heat addition by radiative transfer occurs. This is without the erroneous presumption of entropy destruction anywhere in the cycle. Thus, the Clausius inequality indicates reversibility for a cycle that includes an irreversible process. Further, in some radiative cases the quantity đQ/T, where T is the boundary temperature, is not the entropy transfer at the system boundary, and in fact, primarily represents entropy production within the system. It is also clear that in another case considered, the quantity đQ/T had no physical meaning whatsoever. Consequently, the Clausius expression has been re-stated so that it is applicable to cycles with processes involving any form of heat transfer. A new integrand (đQ_cc/T + đS_Net,Rad) is presented, allowing the Clausius inequality to generally apply to all heat transfer scenarios. The work in this paper emphasizes the need to re-state other fundamental equations allowing applicability to all heat transfer processes, and draws attention to the unique character of radiative entropy calculations.     

Cooling and Solidification of Melted Drops in an Immiscible Cooling Medium

The cooling and solidification of melted drops during their movement in an immiscible cooling medium is widely employed for granulation in the chemical industry, and a study of these processes to provides a basis for the design of the granulation tower height and the temperature of the cooling medium is reported. A physical model of the cooling and solidification of the drop is established and the numerical calculation is performed. The influences of the key factors in the solidification, i.e., Bi number, drop diameter, temperature of the cooling medium, etc. are presented. The cooling and solidification during wax granulation in a water‐cooling tower and during urea granulation in an air‐cooling tower (spraying tower) are described in detail. Characteristics of the solidification and temperature distribution within the particle at different times are shown. The model and calculations can be used for structure design of the granulation tower and optimization of the operation parameters.     

Thermal-lens and photo-acoustic methods for the determination of SiC thermal properties

In this paper we report the use of photothermal techniques such as Thermal lens (TL) spectrometry, Photoacoustic and heat capacity, ρc_p, to determine the thermo-optical parameters, such as thermal conductivity (K), thermal diffusivity (D), specific heat (c_p) and the optical path dependence with temperature (ds/dT), of an undoped polycrystalline 3C-SiC. To our knowledge, this is the first time that Thermal lens technique is used for wide band-gap systems. Results obtained for the polycrystalline sample with TL technique indicates that ds/dT is negative at room temperature. Moreover, the obtained values of thermal diffusivity and thermal conductivity are in good agreement with that found in the literature, indicating that the phototermal techniques can be used to obtain the referred parameters in circumstances where other techniques cannot be used, for example, in harsh environments.