大尺寸磷酸盐激光钕玻璃批量制备技术研发及应用

为满足神光装置发展和未来国家专项工程对大尺寸激光玻璃的大量需求,上海光学精密机械研究所研发了以磷酸盐激光钕玻璃连续熔炼技术为核心的大尺寸激光钕玻璃批量制备技术.大尺寸磷酸盐激光钕玻璃批量制备技术是全新的工艺技术,先后攻克了除杂质、动态除羟基、除铂颗粒、小流量大尺寸成型、隧道窑退火过程玻璃易炸裂以及包边和性能检测等一系列关键单元技术,激光玻璃的所有指标包括荧光寿命、光学损耗、光学均匀性、包边剩余反射率等均达到神光装置的使用要求.使中国成为继美国之后第二个拥有大尺寸激光钕玻璃批量制造能力的国家.采用该技术已成功研制了一千多片米级尺寸N31型激光钕玻璃,并且应用于我国的神光系列装置,在中国工程物理研究院实现了1 053 nm激光波长5 ns脉冲宽度单束能量19.6 kJ激光输出.采用本技术研制的激光钕玻璃在国防、强场激光科技前沿、激光加工和医疗领域都得到推广应用.     

Reverse-transformation austenite structure control with micro/nanometer size

To control the reverse-transformation austenite structure through manipulation of the micro/nanometer grain structure, the influences of cold deformation and annealing parameters on the microstructure evolution and mechanical properties of 316L austenitic stainless steel were investigated. The samples were first cold-rolled, and then samples deformed to different extents were annealed at different temperatures. The microstructure evolutions were analyzed by optical microscopy, scanning electron microscopy (SEM), magnetic measurements, and X-ray diffraction (XRD); the mechanical properties are also determined by tensile tests. The results showed that the fraction of stain-induced martensite was approximately 72% in the 90% cold-rolled steel. The micro/nanometric microstructure was obtained after reversion annealing at 820-870℃ for 60 s. Nearly 100% reversed austenite was obtained in samples annealed at 850℃, where grains with a diameter ≤ 500 nm accounted for 30% and those with a diameter >0.5 μm accounted for 70%. The micro/nanometer-grain steel exhibited not only a high strength level (approximately 959 MPa) but also a desirable elongation of approximately 45%.     

Effect of vanadium carbide on commercial pure aluminum

The effect of vanadium carbide (VC) on the grain size of commercial pure aluminum was experimentally investigated by varying the content of VC, the holding time, and casting temperature. The refining efficiencies of VC and Al5Ti1B were also compared. The refined samples of commercial pure aluminum were examined using optical microscopy, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The results suggest that VC is a good refiner of commercial pure aluminum. The addition of only 0.3wt% VC can decrease the grain size of aluminum to 102 μm, whereas the casting temperature and holding time have little effect on the grain size. The refining efficiency of VC is better than that of Al5Ti1B. The VC particles in molten aluminum act as nuclei and the grain refinement of aluminum alloys by VC particles is achieved via heterogeneous nucleation.     

Investigation of the deterioration of passive films in H<Subscript>2</Subscript>S-containing solutions

The effect of H₂S on the corrosion behavior of 316L stainless steel was investigated using electrochemical methods by changing the gas condition from CO₂ to H₂S and then back to CO₂. The presence of H₂S showed an acceleration effect on the corrosion of 316L stainless steel in comparison with CO₂. The acceleration effect remained even after the complete removal of H₂S by CO₂, indicating that the passive film was irreversibly damaged. X-ray photoelectron spectroscopy (XPS) analysis indicated that the passive film was composed of Cr₂O₃, Fe₂O₃, and FeS₂ after being immersed in H₂S-containing solutions. The semiconducting property of the passive film was then investigated by using the Mott-Schottky approach. The presence of sulfides resulted in higher acceptor and donor densities and thus was responsible for the deterioration of passive films.     

保护医学——一个正在兴起的交叉学科

保护医学作为一门新兴的交叉学科已受到广泛瞩目。保护医学涉及人类健康、动物健康和生态系统健康3个层面,它们构成有机的整体,相互影响,相互作用,缺一不可。保护医学研究的最终目标是实现生态的健康,这是保证包括人类在内的生命健康的根本前提。它强调健康与生态、环境之间的联系,体现了多学科的交叉,如人类健康和公共卫生、流行病学、兽医学、毒物学、生态学和保护生物学等,而且其研究方法也体现出多学科交叉的特点。     

新型掺铒硼铋锶酸盐玻璃的J-O参数计算

用高温熔融法制备了成分为：B2O3-Bi2O3-SrO的新型掺铒硼铋锶酸盐玻璃．测试了样品的发射光谱和吸收光谱．利用Judd—Ofelt理论计算了该玻璃样品的J-O参数（Ω2,Ω4,Ω6）和Er^3＋各相关能级的理论振子强度、实验振子强度等发光参数,并对其发光特性进行了研究．计算结果表明：该硼铋锶酸盐玻璃的共价性强于已被报道的大多数玻璃,且其跃迁几率最大的两个能级为^4I13/2和^4I15／2能级．     

mRNA detection in living cell using phosphorothioate-modified molecular beacon

In this study, GFP mRNA in COS-7 cell and GFP-transfected COS-7 cell was detected in real time using phosphorothioate-modified molecular beacon based on living cell imaging method. Results showed that phosphorothioate-modified molecular beacon still kept the advantages of molecular beacon, such as, excellent selectivity, high sensitivity, and no separation detection. In addition, this modification could significantly increase the nuclease resistance of molecular beacon. Phosphorothioate-modified molecular beacon can efficiently reduce the false positive signal and improve the accuracy of living cell mRNA detection. Supported by the National Key Basic Research Program (Grant No. 2002CB513110), International Technologies Collaboration Program of China (Grant No. 2003DF000039), and National Natural Science Foundation of China (Grant Nos. 90606003 and 20620120107)     

银纳米粒子在聚苯乙烯球表面的异相成核与生长

采用原位化学还原法,将银纳米颗粒直接沉积到没有进行任何活化处理的聚苯乙烯（Polysty-rene,PS）亚微米球的表面.运用X射线衍射（XRD）、透射电子显微观察（TEM）和X射线能谱（EDS）等分析手段对产物的成分、形态、尺寸、以及分布等特征进行了详细表征.结果表明,产物为大量均匀的PS-Ag复合粒子,银纳米粒子以带状为主,并沿着球形基体的弧形表面不连续分布.高分辨电子显微分析（HRTEM）表明,银粒子均为结晶度较高的单晶,它们与非晶PS球形基体之间结合的很好,这应归因于银在基体表面的异相成核及沿着与球面切向方向的生长.此外,研究了反应物浓度、温度等因素对银纳米粒子在PS球表面沉积的影响.根据实验结果,详细探讨了原位化学还原过程中银纳米粒子在非晶PS球表面的异相成核与生长的机理.     

锂离子在混凝土碱集料反应过程中的作用

在采用X射线衍射分析、化学组成分析和偏光显微镜分析对硅质碳酸盐集料的矿物学特征充分研究的基础上,研究了锂离子迁移渗透在混凝土碱集料反应过程中的行为特征.混凝土棱柱法(CSA A23.2-14A或ASTM C 1293)所测的膨胀结果表明:掺加[Li]/[Na+K]摩尔比1.11的LiNO3-能有效抑制混凝土碱集料反应膨胀;锂玻璃不仅不能抑制碱集料反应膨胀甚至会在一定程度上促进膨胀;与单一掺加混合材(粉煤灰或矿渣)相比,LiNO3与混合材的复合在一定程度上增强了相应的膨胀抑制效果;在混凝土碱集料反应过程中,存在Li+与Na+,K+之间的竞争.相对而言,Li+具有一定的优势.这与锂盐能表现出一定的混凝土碱集料反应膨胀抑制效果相一致.此外,强度对比研究结果表明,掺加锂盐一定程度上降低了混凝土的强度.     

闭孔泡沫铝特征统计及其变形行为实验研究

以椭圆拟合长方体闭孔多边形泡沫铝表面孔截面,运用统计学的方法研究了泡沫铝试件表面孔的大小、形状和方位等分布特征.统计结果表明:上述孔的各项几何特征参数除方位外服从高斯分布. 应用图像处理技术,获取了单轴压缩变形前后泡沫铝试件的表面图像.利用序列数字图像相关方法对泡沫纯铝变形前后的图像进行相关计算,获得了静态单向压缩条件下闭孔泡沫铝材料表面全场变形及局部孔结构的变形,同时根据试验结果计算了试件的名义应力-应变曲线,给出了压缩过程中孔壁的失效顺序和破坏规律.对块体材料的压缩实验表明,泡沫纯铝是以多个断裂带的形式破坏和吸收能量.