FAN7310电子镇流器控制电路的工作原理与应用

本文介绍了FAN7310的特点、工作原理，并对其典型应用电路进行了分析。     

脱β层梯度硬质合金的制备及组织结构

采用1步烧结法,在原料粉末中添加中颗粒Ti(C,N)的情况下制备表面含脱β层的梯度结构硬质合金。分别采用扫描电镜(SEM)、X射线衍射(XRD)及能谱技术(EDS)分析合金样品的微观组织、相组成及成分分布。结果表明,在1 420℃下真空烧结时,初始成分不含Ti(C,N)的合金样品的组织为均质结构,由WC,Co基粘结相及(Ti,W)C三相组成;初始成分含有Ti(C,N)的合金样品表层形成了脱β层,脱β层中仅存在WC,Co基粘结相2相,芯部的组织除WC,Co基粘结相及(Ti,W)C 3相以外,还存在少量近球形未溶解的Ti(C,N)核心。脱β层既是1个缺立方相层,也是1个富钴层。     

Analytical model for CHF in narrow gaps with surface orientation effects

The CHF in rectangular narrow gaps has been investigated to develop a reasonable predictive model for CHF, accounting for the surface orientation effects. The model was based on Wallis formulation of the counter current flow limitation (CCFL) for flooding of the flow entrance gap. The results by the predictive model were compared with the experimental data by Kim and Suh (2003), and a good agreement was obtained for gap sizes of 1 mm and 2 mm with surface inclination angles ranging from 15° to 90°. However, when the surface inclination angle was less than 15° (nearly downward-facing position), the predictive model underestimated the CHF. A modified Katto–Kosho correlation based on Kutateladze approach was further proposed and it could predict the CHF well for inclination angles less than 15°, due to the surface tension effects. For the gap sizes of 5 mm and 10 mm, the predictive results were far larger than experimental data by Kim and Suh. And the large differences between the predictive results and experimental data were attributed to the fact that the mechanism of CHF in large gap is quite different from a narrow gap. It indicated that the validity of the model based on CCFL was limited to gaps of less than 5 mm. The present work is instructive for the safety analysis of the lower head of PWR in case of core meltdown during severe accident.     

Development of counter-current flow limitation model applicable to a sharp-edged liquid entrance

There are many industrial machines that function by operation of multi-phase fluids. Some of them take advantage of the characteristics of counter-current two-phase flow. The maximum flow rates of gas and liquid phases which flow in opposite-directions (counter-current flow) are limited by a phenomenon known as a Counter-Current Flow Limitation (CCFL or flooding). The mass and momentum conservation equations for two phases were established to build a system of first-order partial derivative equations (PDE). A new CCFL model was developed based on the characteristic equation of the first-order PDE system. The present model applies to the case in which a non-uniform flow is developed around a square or sharp-edged entrance of liquid phase. The model can be used to predict the operating-limit of components in which mass and heat transfer are taking place between liquid and gas phases.     

浅谈由灯管光线利用率估算背光模组表面辉度的一般方法

提高背光模组灯管光线的利用率是增加背光模组表面辉度的有效方法之一。本文主要介绍当已知背光模组中灯管光线的利用率后，对背光模组的表面辉度进行估算的一般办法。     

液晶背光用冷阴极荧光灯劣化老化原因及对策研究

冷阴极荧光灯（CCFL）是液晶背光模组的主要部件之一,它的优劣会直接影响背光模组的光学性能。文章较为全面地分析了冷阴极荧光灯亮度衰减的常见原因,并对延长冷阴极荧光灯使用寿命的方法做了深入的研究和总结。     

LCD背光用LED的封装技术

We design a package patterned with red and green emitting phosphors excited by a blue LED to emit tri-basic mixing color.For high backlight display quality, we compare several phosphors.According to our measurements, green phosphors 0752G, 0753G and red phosphor 0763R are preferred for producing a good backlight source.Compared to RGB-LED backlight units, this frame typically benefits the lighting uniformity, and can sim-plify the structures.It also provides higher color render and better CCT than the traditional package method of a yellow phosphor with a blue chip.However, its light efficiency needs to be further improved for the use of backlights for LCDs.     

Experimental CFD grade data for stratified two-phase flows

Stratified two-phase flows were investigated at two test facilities with horizontal test-sections. For both, rectangular channel cross-sections were chosen to provide optimal observation possibilities for the application of optical measurement techniques. In order to show the local flow structure, high-speed video observation was applied, which delivers the high-resolution in space and time needed for CFD code validation.The first investigations were performed in the Horizontal Air/Water Channel (HAWAC), which is made of acrylic glass and allows the investigation of air/water co-current flows at atmospheric pressure and room temperature. At the channel inlet, a special device was designed for well-defined and adjustable inlet boundary conditions. For the quantitative analysis of the optical measurements performed at the HAWAC, an algorithm was developed to recognise the stratified interface in the camera frames. This allows to make statistical treatments for comparison with CFD calculation results. As an example, the unstable wave growth leading to slug flow is shown from the test-section inlet. Moreover, the hydraulic jump as the quasi-stationary discontinuous transition between super- and subcritical flow was investigated in this closed channel. The structure of the hydraulic jump over time is revealed by the calculation of the probability density of the water level. A series of experiments show that the hydraulic jump profile and its position from the inlet vary substantially with the inlet boundary conditions due to the momentum exchange between the phases.The second channel is built in the pressure chamber of the TOPFLOW test facility, which is used to perform air/water and steam/water experiments at pressures of up to 5.0 MPa and temperatures of up to 264 °C, but under pressure equilibrium with the vessel inside. In the present experiment, the test-section represents a flat model of the hot leg of the German Konvoi pressurised water reactor scaled at 1:3. The investigations focus on the flow regimes observed in the region of the elbow and of the steam generator inlet chamber, which are equipped with glass side walls. An overview of the experimental methodology and of the acquired data is given. These cover experiments without water circulation, which can be seen as test cases for CFD development, as well as counter-current flow limitation experiments, representing transient validation cases of a typical nuclear reactor safety issue.     

采用冷阴极荧光灯的液晶背光源设计

目前ＬＣＤ用背光源中，冷阴极荧光灯是主流，本文从ＬＣＤ对背光源的要求出发，重点介绍了冷阴极荧光灯的设计要点。为提高发光效率和改善启动特性，需合理确定灯管直径、适当选择充入气体的种类和压力，以满足ＬＣＤ低功耗，低电压启动等方面的实用需要。