引导部分本科生较早进入科研工作刍议

文章从引导部分本科生较早进入科研工作的必要性、方法和应注意的问题几个方面进行了讨论。作者认为,引导部分本科生在大学二年级后即逐步进入科研工作,有利于从本科生中培养科研尖子,从而提高全体学生在大学四年级进行毕业论文或设计工作时的水平,符合素质教育的要求。     

精细化工专业实验教学改革浅探

针对当前地方本科院校精细化工专业自身的特点,结合近几年的实验教学经验,分析了实验教学存在的问题与不足,从更新教学内容、改革实验方法、合理安排教学时间、改进教学手段、改革教学途径等5个方面对精细化工专业实验教学改革进行了探索与实践,对培养学生创新意识、应用能力,提高学生综合素质和科研素养具有重要的意义。     

氟代碳酸乙烯酯的合成方法综述

综述了氟代碳酸乙烯酯的制备方法。其制备方法主要有两种:一、直接氟化法:以氟气、氮气和碳酸乙烯酯为原料在高温高压条件下的一步合成法;二、卤素交换法:碳酸乙烯酯先经过氯代反应生成氯代碳酸乙烯酯,然后与氟化试剂进行卤素取代反应制备氟代碳酸乙烯酯。并重点介绍了卤素取代反应中使用不同的催化剂用来合成氟代碳酸乙烯酯。     

Modeling photon transport in fluorescent solar concentrators

Fluorescent solar concentrators (FSC) can concentrate light onto solar cells by trapping fluorescence through total internal reflection. In an ideal FSC, the major obstacle to efficient photon transport is the re‐absorption of the fluorescence emitted. In order to decompose the contribution of different photon flux streams within a FSC, the angular dependent re‐absorption probability is introduced and modeled in this paper. This is used to analyze the performance of different FSC configurations and is also compared with experimental results. To illustrate the application of the modeling, the collection efficiency of ideal devices has also been calculated from the re‐absorption probability and is shown to be useful for estimating non‐ideal losses such as those due to scattering or reflection from mirrors. The results also indicate that among the FSCs studied, the performance of those surrounded by four edge solar cells is close to ideal. The rapid optimization of FSCs has also been presented as another practical application of the models presented in this paper. © 2014 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons, Ltd.     

Anodizing of etched aluminum foil coated with modified hydrous oxide film for aluminum electrolytic capacitor

Prior to galvanostatical anodization in boric acid solution, aluminum capacitor foil with a tunnel etch structure is treated in a two-step process in which a non-dense hydrous oxide film is first formed on foil in neutral boiling water for 10 min [namely, conventional hydration (CH)] and the hydrous oxide is then modified in a 80 °C weakly acidic solution containing trace amount of citric acid for 3 min [namely, modified conventional hydration (MCH)]. After modification, the hydrous oxide film becomes dense and thin. Time variations in the anode potential during anodizing were monitored, and the structure and dielectric properties of the anodic oxide films were examined by transmission electron microscopy, X-ray diffraction and electrochemical impedance spectroscopy measurements. It was found that the MCH-induced hydrous oxide film results in a decreased power consumption during anodization and an increased crystallized anodic oxide film, which has a high specific capacitance and a low specific resistance, comparing with the CH-induced hydrous oxide film.     

Effects of rotating magnetic fields on thermocapillary flow: Comparison of the infinite and the Φ1–Φ2 models

Convection control of three-dimensional thermocapillary flow by a rotating magnetic field (RMF) was simulated numerically, and the RMF infinite and RMF Φ₁–Φ₂ models were compared. The results of using both RMF models demonstrate that the transverse RMF stirs convection in an azimuthal direction and suppresses convection in the axial direction, which is helpful for the three-dimensional melt convection to become axisymmetric. Compared to the RMF Φ₁–Φ₂ model, however, the over-simplified RMF infinite model leads to a relatively large deviation. With the same magnetic field (7 mT, 50 Hz), the RMF infinite model results in a larger azimuthal velocity and a smaller axial velocity.     

A low-cost method of fabricating hybrid micro-nano fluidic chip by double-layer PDMS mold and UV–thermal nanoimprinting

Micro-nano fluidic chips have become important tools in biomedical testing and research, their more frequent and diverse application being hampered mainly by their high cost, reflective of complex and expensive production methods. Our study introduces a simple, cost-effective new procedure whereby a sturdy PDMS mold consisting of two layers of poured PDMS with a photomask film bonded between them is used for replicating a hybrid micro-nano structure on a SU-8 substrate. The bottom surface of the mold receives a pattern of nano-ridges by pouring the first layer of PDMS on a 2D silicon nano-mold obtained by plasma etching after inclined Cu deposition. Using the double-layer PDMS mold, nano-channels can be imprinted with micro-channels cross-linked through the photomask in a single step of UV–thermal imprinting. The advantages of our end product, a chip with 205-μm-wide and 10-μm-deep micro-channels, cross-linked with 158-nm-wide and 90-nm-deep nano-channels, are its high precision and low cost.     

伊敏三号露天矿疏干防排水设计

为了保障采矿工作的安全顺利进行,并且可以给电厂用水提供稳定水源,通过类比等方法估算出三号矿地下水赋存情况,并对与一号矿交叉开采时的防排水提出了建议。