Fe~(3+)掺杂TiO_2薄膜材料的制备与光催化性能研究

以载玻片为基材,通过溶胶-凝胶技术制备Fe3+离子掺杂的TiO2薄膜。采用甲基橙作为目标降解物,研究Fe3+掺杂薄膜的光催化活性,采用X-射线衍射、扫描电镜和紫外-可见光吸收谱等技术对薄膜相关特征进行了表征。研究表明,当Fe/Ti物质量比为0.25%时,光催化活性最高。经500℃焙烧2h制备TiO2薄膜具有锐钛矿结构,TiO2粒子大小均匀,有孔隙结构。掺杂Fe3+使薄膜TiO2粒子减小,孔隙率增加,而粒子粒径分布不均匀增加,且吸收强度增加吸收边有一定的红移。     

煤矿矿井安全培训仿真系统

在煤矿管理和生产中,要降低事故风险和减少事故死亡人数,就要求管理人员和井下工作人员能够熟练掌握安全生产和防灾避灾的知识和技能,要达到这样的要求,经济、高效的安全培训是必不可少的,而仿真训练是最好的方法。针对上述问题,在此讨论了现有安全培训系统存在的问题,并提出具体的解决方案,基于VisualC＋＋开发工具,开发了煤矿矿井安全培训仿真系统,实现了井下巷道系统模块、灾害再现系统模块和工作安全培训模块等功能,很好地解决了上述问题。     

MIMO技术及在3G中的应用

介绍MIMO技术的定义和历史,从空间复用、传输分集技术、波束成型等方面对MIMO技术进行说明,并对MIMO在3G(HSPA+)中的应用做了简单的描述。     

NAD^＋的多形态和不规则

此研究采用理论计算得出NAD^＋的优化结构为环形。NAD^＋中有五个较强的O-H和N—H拉伸振动方式。经研究,由于O-H…O和N-H…N氢键的方向不同,发现了NAD^＋许多重要形式中的五种多形态。NAD^＋呈环状,能与一些分子反应。应用剪切力的概念,讨论了NAD^＋多形态的机理。说明了NAD^＋的作用机理。NAD^＋是一种辅酶,由于形状的改变而成为不规则,即NAD^＋呈现多形态。在NAD^＋的多形态中,最稳定的结构具有最小的熵。经热力学研究发现,NAD^＋的多形态和低熵值归因于反应中的负Gibbs自由能。讨论了NAD^＋的多形态对其与食物反应的影响。至于NAD^＋的不规则,它取决于NAD^＋分子周围分子的本身性质。     

DFT Study of the Solvent Effects on the Structure, UV-Vis Spectra and the Antioxidant Activity of Caffeic Acid Phenethyl Ester and Some of Its Derivatives

In this study, the antioxidative （3-methyl-2-butenyl caffeate）, BC efficiency of CAPE （caffeic acid phenethyl ester） and four of its derivatives （MBC （benzoic caffeate）, P3HC （phenethyl-3-hydroxy-cinnamate） and P4HC （phenethyl-4-hydroxy-cinnamate）） are compared in vacuum and in seven solvents. It turned out that the AA （antioxidant activity） in increasing order was P3HC 〈 P4HC 〈 CAPE 〈 MBC. Effects of solvents on the structure and the antioxidant activity of P3HC, P4HC, BC, MBC and CAPE, were studied at 133LYP/6-31G （d, p） then B3LYP/6-3 I＋G （d, p） level of theory using the conductor polarized continuum model methods. Thermodynamically, the authors showed that solvent effects on bond dissociation enthalpy are very weak （within 25 kJ/mol）, but sufficient to influence hydrogen bonds, O-H bond lengths and showed the preferential sites of hydrogen atom cleavage. In addition, solvent notably influences and changes the nature of the scavenging process of ROS （reactive oxygen species）, favouring by this way the HHAT （homolytic hydrogen atom transfer） in non polar solvents, the SPLET （sequential proton loss electron transfer） in polar solvents. Moreover, in chloroform and for the five molecules studied the SET-PT （sequential electron transfer proton transfer） mechanism is preferred compared to the HHAT, because in this solvent the IP is lower than the BDE. TD-DFT calculations revealed that solvent induce a bathochromic effect （red-shift of the wavelengths） coupled to hyperchromic or hypochromic effects.     

机插秧田杂草防除试验研究

2013年进行了机插秧田杂草防除试验研究。结果表明:55%吡嘧·丙草胺WP 1125.0 g/hm2封闭效果最理想,药后20,45 d,封闭综合防效分别为93.75%、92.63%,与55%吡嘧·丙草胺WP 750.0~937.5 g/hm2的防效54.38%~75.00%、51.48%~72.88%及对照药剂50%苄·丁·异丙隆WP 1200.0 g/hm2、53%苄嘧·苯噻酰WP 1200.0 g/hm2的防效76.87%~87.50%、72.07%~85.31%差异极显著。在试验剂量条件下,药剂对水稻安全。     

论“白＋黑”路面反射裂缝的防治与处理

本文主要针对旧水泥混凝土路面加铺沥青层的问题进行论述,并着重阐述“白＋黑”路面反射裂缝的防治与处理问题,提出合理化的建议和措施。     

基于ETM＋数据的广西甘蔗信息提取方法初探

利用ETM＋高分辨遥感数据对甘蔗监测的研究,在遥感数据中提取甘蔗空间分布信息,同时进行面积估算。在分区范围内采用决策树分类和监督分类相结合的方法,取得了理想的效果,以供读者学习和参考。     

Optical Spectra and Gain Properties of Ho3＋/Pr3＋ Co-doped LiYF4 Crystal

The LiYF4 single crystals singly doped Ho3＋ and co-doped Ho3＋, Pr3＋ ions were grown by a modified Bridgman method. The Judd-Ofelt strength parameters （Ω2, Ω4, Ω6） of No3＋ were calculated according to the absorption spectra and the Judd-Ofelt theory, by which the radiative transition probabilities （A）, fluorescence branching ratios （β） and radiative lifetime （τ rad） were obtained. The radiative lifetimes of 5/6 and 5/7 levels in Ho3＋ （1 mol%）：LiYF4 are 10.89 and 20.19 ms, respectively, while 9.77 and 18.50 ms in Ho3＋/pr3＋ doped crystals. Hence, the τ rad of 5/7 level decreases significantly by introduction of Pr3＋ into Ho3＋：LiYF4 crystal which is beneficial to the emission of 2.9 μm. The maximum emission cross section of Ho3＋：LiYF4 crystal located at 2.05 μm calculated by McCumber theory is 0.51 ×10-20 cm2 which is compared with other crystals. The maximum emission cross section at 2948 nm in Ho3＋/pr3＋ co-doped LiYF4 crystal obtained by Fuchtbauer- Ladenburg theory is 0.68 × 10-20 cm2, and is larger than the value of 0.53 × 10-20 cm2 in Ho3＋ singly doped LiYF4 crystal. Based on the absorption and emission cross section spectra, the gain cross section spectra were calculated. In the Ho3- ions singly doped LiYF4 crystal, the gain cross sections for 2.05 μm infrared emission becomes positive once the population inversion level reaches 30%. It means that the pump threshold for obtaining 2.05 μm laser is probably lower which is an advantage for Ho3＋-doped LiYF4 2.05 μm infrared lasers. The calculated gain cross section for 2.9 μm mid-infrared emission does not become positive until the population inversion level reaches 40% in Ho3＋/pr3＋：LiYF4 crystal, but 50% in Ho3＋ singly doped LiYF4 crystal, indicating that a low pumping threshold is achieved for the H03＋：5/6 → 5/7 laser operation with the introduction of Pr3＋ ions. It was also demonstrated that Pr3＋ ion can deplete rapidly the lower laser Ho3＋：5/7 level and has influence on t     

热处理温度及EDTA对β-NaYF_4:Yb~(3+),Er~(3+)材料结构与性能的影响

采用共沉淀法合成了Yb3+、Er3+共掺杂的NaYF4粉体,重点研究了热处理温度和螯合剂EDTA对所合成粉体的晶相、表面形貌以及上转换发光性能的影响,并利用X射线衍射、扫描电镜及荧光光谱对其结构组成、晶体表面形貌及发光性能进行了研究。结果表明:随着热处理温度的升高,NaYF4:Yb3+,Er3+粉体由立方相向六方相转变,当温度高于600℃时又从六方相逐渐转变为立方相,而且颗粒的尺寸逐渐变大,从近似球形到无规则形状;NaYF4:Yb3+,Er3+发光强度与热处理温度密切相关,热处理温度对于β-NaYF4:Yb3+,Er3+的发光性能有着重要的影响。经过600℃热处理后的粉体具有较高的发光强度;螯合剂EDTA的添加对所合成粉体的发光性能有着明显的影响,螯合剂的添加降低了其发光强度;在1 000℃以内,NaYF4:Yb3+,Er3+具有良好的热稳定性。