新一轮教育改革和远程开放教育的发展(三)

正如很多专家学者和业内人士所认为的,在"现代远程教育工程试点"十年之际,讨论普通高校远程教育的发展问题,系统的总结与深入的反思是不可回避的。试点目标的实现与落实情况如何,十年试点中积累的主要经验、形成的主要特色有哪些,试点过程中遭遇的深层次问题是什么、有哪些矛盾至今尚未解决,远程教

共溅射和离子注入制备的SiO_2（Eu）薄膜中Eu~（3＋）到Eu~（2＋）的转变

采用共溅射方法和Eu离子注入热生长的SiO_2方法得到SiO_2(Eu)薄膜，Eu离子的浓度为4%和0.5%。对样品X射线吸收近边结构(XANES)的研究和分析表明，在高温氮气中发生了Eu~(3+)向Eu~(2+)的转变。SiO_2(Eu)薄膜高温氮气退火下蓝光的发射证明了这一结论

铕离子注入氧化硅膜光发射的研究

采用铕离子注入热生长SiO_2薄膜的方法，获得掺杂剂量为10~(14) cm~(-2)及10~(15)cm~(-2)的SiO_2:Eu~(3+)硅基复合膜，研究了该薄膜的光致发光退火特性。经1000℃退火后观察到Eu~(3+)的红光发射。在1200℃下氮气中退火观察到Eu~(2+)450 nm的强光发射。讨论了Eu~(3+)向Eu~(2+)的转变

掺Sn的In_20_3透明导电膜生长优先取向对其光电性能的影响

采用反应热蒸发法制备掺sn的In_20_3（ITO）透明导电膜，系统研究了ITO薄膜生长的优先取向对其光电性能的影响，结果表明，ITO薄膜（400）取向的优先生长对其透过率影响很小，但可明显增加载流子迁移率，从而有效降低了薄膜的方块电阻。在两个相同的薄膜硅／单晶硅太阳能电池上分别沉积（222）和（400）ITO优先取向膜，光电转换效率分别为10．3％和12．9％，表明（400）取向更有利于提高电池效率。经优化，最佳衬底温度（T_s）为225℃，最佳氧流量（fo_2）为4sccm。在优化的沉积条件下制备ITO薄膜，其电阻率可达到4.8x10~(-4)Ω·cm，可见波段的透过率大于90％，性能指数为3.8×10~(-2)□/Ω

利用x射线小角散射技术研究微晶硅薄膜的微结构

采用x射线小角散射(SAXS)技术研究了由射频等离子体增强化学气相沉积(rf-PECVD)、热丝化学气相沉积(HWCVD)和等离子体助热丝化学气相沉积(PE-HWCVD)技术制备的微晶硅(μc-Si:H)薄膜的微结构.实验发现,在相同晶态比的情况下,PECVD沉积的μc-Si:H薄膜微空洞体积比小,结构较致密,HWCVD沉积的μ-Si:H薄膜微空洞体积比大,结构较为疏松,PE-HWCVD沉积的μc-Si:H薄膜,由于等离子体的敲打作用,与HWCVD样品相比,微结构得到明显改善.采用HWCVD二步法和PE-HWCVD加适量Ar离子分别沉积μc-Si:H薄膜,实验表明,微结构参数得到了进一步改善.45°倾角的SAXS测量显示,不同方法制备的μc-Si:H薄膜中微空洞分布都呈各向异性.红外光谱测量也证实了SAXS的结果

低温制备微晶硅薄膜生长机制的研究

采用热丝化学气相沉积技术制备了一系列处于不同生长阶段的薄膜样品,用原子力显微镜系统地研究生长在单晶硅衬底和玻璃衬底上薄膜表面形貌的演化.按照分形理论分析得到:在玻璃衬底上的硅薄膜以零扩散随机生长模式生长;而在单晶硅衬底上,薄膜早期以有限扩散生长模式生长,当膜厚超过某一临界厚度时转变为零扩散随机生长模式.岛面密度与膜厚的依赖关系表明,在临界厚度时硅衬底和玻璃衬底上的岛面密度均出现了极大值.Raman谱的测量证实,玻璃衬底上薄膜临界厚度与非晶/微晶相变之间存在密切的关系.不同的衬底材料直接影响反应基元的表面扩散能力,从而造成薄膜早期生长模式的差异

NMR-based metabolomic analysis on the extracts of whole tissue from flounder Paralichthys olivaceus

As an-omic technique in system biology, nuclear magnetic resonance(NMR) -based metabolomics has been widely used in marine biology in recent years.Due to the high salinity of marine environment, there exists substantial differences of metabolite abundances in marine organisms compared with other organisms.To deal with the high salinity of seawater, marine organisms use very high concentrations of osmolytes, such as taurine, betaine and trimethylamine N-oxide, to balance the osmolarity.Generally, the concentrations of osmolytes are hundreds of times higher than other metabolites, leading to extreme imbalance of weights of metabolites.Therefore, a suitable data preprocessing was the key procedure to accurately analyze the metabolomic data from marine organisms.In this work, the juvenile flounder Paralichthys olivaceus was exposed to a reduced salinity(50 % normal salinity, 15.6 psu).After exposure for 48 h, the one dimensional ~1H NMR spectroscopy was used to analyze the metabolomes of flounder samples.To investigate the influences of data preprocessing, the metabolomic data of founder samples were subjected to three different data preprocessing methods(unit variance scaling, Pareto scaling and generalized log transformation -mean centering) before pattern recognition analysis.Results indicated that the concentration of osmolyte, trimethylamine N-oxide, was approximately 200 times higher than other metabolites in flounder samples.The reduced salinity induced significant metabolic responses in juvenile flounder.After orthogonal partial least squares-discriminant analysis(OPLS-DA), generalized log transformation-mean centering was found to be the best data preprocessing method, presenting 8 significantly altered metabolites induced by reduced salinity, which was consistent with the quantitative analysis of metabolites.Overall, this study provided a suitable data preprocessing method to analyze the metabolomic data of flounder P.olivaceu