方波激发下Ho3+上转换绿色发光粉的激发机理

采用溶胶-凝胶法制备了BaGd2ZnO5:Yb3+,Ho3+的发光材料,测量了样品在不同激发密度下的上转换光发射光谱。用方波调制的971 nm LD激光激发样品得到上转换绿光发射的上升和衰减变化曲线,通过建立Ho3+离子5F4(5S2)和5I6能级及Yb3+离子2F5/2能级的速率方程,并利用速率方程对绿光的上升和衰减过程进行拟合,确定了Yb3+离子2F5/2能级寿命及Ho3+离子5F4(5S2)和5I6的能级寿命,并证实在Ho3+离子能级粒子数布居趋于稳定时,Yb3+→Ho3+的能量传递是Ho3+离子5F4(5S2)能级粒子的主要布居途径,而激发态吸收对粒子布居数的贡献较小。     

新型抗HIV-1蛋白GRFT的构建、表达及活性研究

根据已知的新型抗HIV-1蛋白GRFT基因氨基酸序列,推测其DNA编码序列,密码子优化及修饰后进行全基因化学合成,连接到原核表达载体pET28a（+）中,转化大肠杆菌BL21(DE3),IPTG诱导表达,获得目的蛋白. SDS-PAGE、Western Blot分析结果表明,目的蛋白得到良好表达并具有抗原活性;对表达条件进行优化,在最佳表达条件下,目的蛋白的表达量可占菌体总蛋白的55.84%;利用Ni2+-NTA柱亲和层析法进行目的蛋白的复性和纯化,凝胶成像系统扫描分析表明,纯度可达94.06%;运用Dot-ELISA法进行复性蛋白的抗原结合活性检测,结果显示,目的蛋白能够与HIV-1膜蛋白抗原特异性结合,初步证明所表达的重组蛋白具有良好的体外结合活性;基于制备的能够表达HIV-1 gp120基因的靶细胞模型,运用IFA法开展目的蛋白的细胞结合活性研究,结果显示,目的蛋白能够与靶细胞发生特异性反应,表明成功制备并获得了具有生物活性的新型抗HIV-1蛋白GRFT,为进一步研制新型抗HIV-1基因工程药物及其靶向治疗制剂奠定了坚实基础.     

Geometry optimizations of benzene clusters using a modified genetic algorithm

A modified genetic algorithm with real-number coding, non-uniform mutation and arithmetical crossover operators was described in this paper. A local minimization was used to improve the final solution obtained by the genetic algorithm. Using the exp-6-1 interatomic energy function, the modified genetic algorithm with local minimization (MGALM) was applied to the geometry optimization problem of small benzene clusters (C6H6)N(N = 2-7) to obtain the global minimum energy structures. MGALM is simple but the structures optimized are comparable to the published results obtained by parallel genetic algorithms.     

密闭环境中人体自身代谢挥发性有机化合物气相色谱/质谱分析

参考EPA TO－14方法,以稍加改装热解析装置Tekmar6000和吹扫捕集装置Tekmar 3000作为进样系统,对密闭环境中人体挥发性有机化合物（VOCs)进行了GC／MS定性分析和外标定量,初步确定了密闭环境中的生活人员给密闭的生活环境带来的污染成分,为密闭环境的气体净化提供了依据。     

Influence of nitrogen implantation into the buried oxide on the radiation hardness of silicon-on-insulator wafers

In order to improve the total-dose radiation hardness of the buried oxide of separation by implanted oxygen silicon-on-insulator wafers, nitrogen ions were implanted into the buried oxide with a dose of 1016 cm-2 , and subsequent annealing was performed at 1100°C. The effect of annealing time on the radiation hardness of the nitrogen implanted wafers has been studied by the high frequency capacitance-voltage technique. The results suggest that the improvement of the radiation hardness of the wafers can be achieved through a shorter time annealing after nitrogen implantation. The nitrogen-implanted sample with the shortest annealing time 0.5 h shows the highest tolerance to total-dose radiation. In particular, for the 1.0 and 1.5 h annealing samples, both total dose responses were unusual. After 300-krad(Si) irradiation, both the shifts of capacitance-voltage curve reached a maximum, respectively, and then decreased with increasing total dose. In addition, the wafers were analysed by the Fourier transform infrared spectroscopy technique, and some useful results have been obtained.     

高剂量注氮对注氧隔离硅材料埋氧层中正电荷密度的影响

为研究注氮改性对注氧隔离硅材料中埋氧层性质的影响,向其埋氧层内注入了10¹⁶ cm^-2的高剂量氮.实验结果表明,与未注氮的埋氧层相比,所有注氮的埋氧层中的正电荷密度显著增加.实验还发现,注氮后的退火可使埋氧层内的正电荷密度进一步上升.但与注氮导致的埋氧层内正电荷密度的显著上升相比,退火时间对注氮的埋氧层内正电荷密度的影响不大.电容-电压测量结果显示,在埋氧层内部,注氮后未退火的样品与在1100 ℃的氮气气氛下退火2.5 h的样品相比,二者具有近似相同的等效正电荷 关键词： 注氧隔离 埋氧 注氮 正电荷密度     

Total dose radiation response of modified commercial silicon-on-insulator materials with nitrogen implanted buried oxide

Nitrogen ions of various doses are implanted into the buried oxide(BOX) of commercial silicon-on-insulator(SOI) materials,and subsequent annealings are carried out at various temperatures.The total dose radiation responses of the nitrogen-implanted SOI wafers are characterized by the high frequency capacitance-voltage(C-V) technique after irradiation using a Co-60 source.It is found that there exist relatively complex relationships between the radiation hardness of the nitrogen implanted BOX and the nitrogen implantation dose at different irradiation doses.The experimental results also suggest that a lower dose nitrogen implantation and a higher post-implantation annealing temperature are suitable for improving the radiation hardness of SOI wafer.Based on the measured C-V data,secondary ion mass spectrometry(SIMS),and Fourier transform infrared(FTIR) spectroscopy,the total dose responses of the nitrogen-implanted SOI wafers are discussed.     

银胶体系中吖啶橙、吡啶共吸附竞争的研究

本文利用光学多道分析仪,着重研究了吖啶橙—银胶—吡啶体系;观察了吖啶橙荧光的两次瞬间增强的时间效应荧光谱;分析了吖啶橙与吡啶在银表面上共吸附竞争以及氯化钾在这一竞争中所起的作用。对于表面与分子间相互作用的这一规律作了初步探讨。     

大庆油田物资采购及库存优化机制设计与模型研究

本文结合大庆油田物资采购中的实际问题, 考虑物资市场、需求、库存三方之间的不确定性和复杂性,分别讨论了物资采购价格时变、物资需求时变、以及不同仓储容量限制下的库存优化模型的研究进展。进一步,设计了针对大庆油田物资的采购及库存优化机制,并选取大庆油田实际采购中的4种A类物资,基于时间序列方法和0-1混合整数规划,分别对机制中的价格预测部分和策略优化部分进行了数值试算,结果表明,基于准确度较高的预测价格,运用混合0-1整数规划模型制定的多品种物资的最优联合采购策略,可以实现采购成本的节省,相比于4种物资2009年的实际采购成本,节约比率高达7.66%,同时价格预测的精度也得到了用户的认可。该机制为油田物资采购和库存优化管理项目中的辅助决策支持系统原型设计提供了参照。但考虑到大庆油田实际采购中的各种复杂因素的影响,还需进一步完善该优化机制,并对相关模型进行改进。     

染料分子荧光淬灭规律研究

本文研究了若丹明B、若丹明6G和吖啶橙三种染料分子吸附于银表面上时的荧光变化规律,发现在银胶颗粒表面的吸附均造成了其荧光强度急剧而大幅度的淬灭,淬灭随时间呈双曲线型衰减。同时利用这一实验结果对分子在表面间的吸附系数与脱附系数——这些表征分子与表面相互作用的重要参数——表达式进行了初步推导。