Correction to the Article “Deformation of Plates of Small Condensers and Belinskii's Problem”

A corrected proof is given of Lemma 4.1 of the above-mentioned article.     

平行板电容器演示实验装置的改进

介绍一种具有干燥、照明和充电系统的演示实验装置，该装置使平行板电容器在演示时能保持所带电荷基本不变。     

Determination of pharmaceutically related compounds by suppressed ion chromatography: I. Effects of organic solvent on suppressor performance

This overall study aims to investigate gradient elution ion-exchange chromatography of pharmaceutically relevant compounds using universal nebulisation detectors, such as evaporative light scattering detection (ELSD). Addition of organic solvents to the eluent is necessary to minimise hydrophobic adsorption on the polymeric stationary phase and improve solubility of analytes. It is also necessary to de-salt the eluent prior to detection, and in this work, ion chromatography suppressors were used for this step. Such suppressors have been designed for aqueous eluents, so the purpose of the present study was to investigate the effects of methanol and acetonitrile on suppressor performance. Chemical and electrolytic suppressors were evaluated for baseline drift, noise and efficiency of suppression using aqueous/organic eluents containing up to 40% (v/v) methanol or acetonitrile. Chemical suppression of aqueous/organic eluents showed minimal noise levels, uniform low baseline and low gradient drift. Electrolytic suppression gave good performance, but with higher baseline conductivity levels and baseline drift than chemical suppression. The elevated baseline was found not to be caused by incomplete suppression of the eluent, but was attributed to chemical reactions involving the organic solvents and facilitated by high electric currents and heat generation. It was demonstrated that suppressed ion-exchange separation using a complex KOH elution profile could be coupled with ELSD, with the suppressor effectively de-salting the eluent, producing a stable baseline. Finally, complementary separation selectivity was demonstrated using a set of pharmaceutically related organic acids separated by reversed-phase and ion-exchange methods.     

菲涅尔太阳能聚光镜的设计

讨论并设计了一种超薄的菲涅尔聚光镜,根据费玛原理设计出以非球面为截面的中心折射区域和T IR(内部全反射)棱镜为锯齿部分的折反区域,用ZEMAX软件优化得到最佳聚光态,并利用ZEMAX软件模拟出菲涅尔聚光镜聚光性及其能量分布,最终得到总厚度仅为30 mm的折反复合型菲涅尔聚光镜。实验结果表明:折反复合型菲涅尔聚光镜不仅能提高太阳能的利用率,同时也使会聚到光电池表面上的能量分布更均匀,复合式菲涅尔聚光镜的性能优于传统的菲涅尔聚光镜。     

湍流参数对凝汽器数值模拟的影响

通过对一凝汽器的二维数值模拟,研究了湍流黏性系数和湍流扩散系数对凝汽器流动与传热特性的影响。结果表明,湍流参数的取值,对凝汽器不凝结率的计算影响较大,对壳侧压降也有一定影响。在凝汽器数值模拟中,采用两方程的RNGκ-ε模型米确定湍流参数,在管束区内部形成湍流参数较大的区域,能更准确描述凝汽器内的复杂流动。与常湍流参数的...     

Performance Analysis of HFC-404A Vapor Compression Refrigeration System Using Shell and U-Tube Smooth and Micro-Fin Tube Condensers

Performance analyses of an HFC-404A refrigeration system for a smooth U-tube condenser and a micro-fin U-tube condenser are carried out for various operating conditions. This article mainly reports performance testing of the above-mentioned condensers for various operating parameters and their effect on the performance of refrigeration systems. The condensers used are shell and U-tube types, with refrigerant through a tube and cooling water through a shell. It also reports the performance enhancement of the system using a micro-fin tube condenser relative to a smooth-tube condenser system. The cooling capacity of the system is increased by 10%, and the coefficient of performance of the system is improved up to 17% using a micro-fin tube condenser.     

凝汽器三维汽相流场与传热特性的数值预测及改善

在采用准三维数值计算方法计算与分析一台双流程凝汽器的三维汽相流动与传热特性的基础上,针对由于冷却 水温度沿流向上升引起的汽流偏斜对传热特性的不利影响,提出一种利用导流板改善流动与传热特性的措施,通过计算证 实了措施的有效性。     

太阳模拟器中椭球面聚光镜参数的确定

椭球面聚光镜是太阳模拟器设备的重要组成部分,其能量收集的效率决定着太阳模拟系统的能量传递效率,而太阳模拟器光学系统中的椭球面聚光镜参数一直没有理论上的设计依据,结合氙灯的发光特性并通过对MATLAB 中建立的椭球面聚光镜聚光过程数值分析模型给出了椭球面聚光镜包括第一焦距、最大成像放大倍率、包容角范围及前后开口直径的确定依据,并通过在Lighttools 中建立的4种仿真模型验证了理论分析的正确性。第一焦距由光源光中心高确定,最大成像放大倍率由光学积分器相对孔径及椭球镜包容角范围共同确定,椭球镜包容角范围不小于30～120,前开直径口由椭球镜的最大孔径角确定,后开口直径由最小孔径角和光源的径向调节量共同确定。该结论给椭球面聚光镜的设计提供了理论支撑,有利于设计完成高能量收集效率的椭球面聚光镜。     

自然复叠制冷系统——一种简易高效分凝器的设计与实验研究

在套管换热器内管中封装干燥剂颗粒制成自然复叠制冷系统的分凝器,系统运行时在分凝器内管中形成气液固三相流化传热传质现象,通过实验发现该种分凝器具有简易高效的特点。还对干燥剂的种类、颗粒大小及体积分率对分凝器性能的影响进行了研究和分析。