一氧化二氮的光电离质谱研究

在入射电子能量2500eV、能量分辨200meV的条件下测量了一氧化二氮分子在7.8～24.5 eV的光学振子强度密度谱和光电离质谱,报道了N2O+、NO+、O+、N2+和N+等离子在较高能量分辨下的部分光学振子强度密度,首次给出了一氧化二氮分子在13.0～21.0 eV能区中性解离的振子强度密度.并在对这些数据进行分析的基础上阐述了一氧化二氮分子超激发态的不同退激发道的竞争过程.     

Distribution of charged lunar dust in the south polar region of the moon

Lunar dust is one of the most threatening problems confronting the return of human beings to the moon. In this work we studied the spatial distribution behavior of charged lunar dust in the solar wind plasma environment in the south polar region of the moon and considered the influence of a mini-crater using Spacecraft Plasma Interactions Software. The distribution of dust and plasma at low solar altitude angles of 20° and 0° was studied, and the spatial density of lunar dust was ~10^10.4 m^-3 and ~10^11.5 m^-3, respectively. This is because a higher surface potential will result in transportation of small dust particles and photoelectrons can also neutralize positively charged lunar dust. The dust density in the plasma void region created by a mini-crater with a 5 m high wall was studied. We obtained a quasi-neutral electric environment in the plasma void region of the mini-crater, and the dust density was about a magnitude lower than that in other regions. The dust risk to a spacesuit is much lower on the nightside than on the dayside, but there is severe charged lunar dust transport in the region between light and shade, which is dominated by the difference in surface and plasma potential caused by photoelectrons.     

大有效面积的高Tc rf SQUID

关键词： c rf SQUID')" href="#">高T_c rf SQUID 新型结构 大有效面积 磁通聚焦器     

苯-水-乙醇三元溶液体系的临界行为

通过等体积滴定法测定了苯-水-乙醇三元部分互溶溶液体系的会溶点曲线；测定了29.00±0.05 ℃时,等溶点附近的等温共存曲线；拟合得到苯-水-乙醇体系序参量临界指数β= 0.38 ± 0.04,序参量临界指前因子K= 1.3 ± 0.2. 说明三元部分互溶溶液体系在等温会溶点附近有非经典临界溶液理论行为, 符合Fisher重正化模型.     

聚合物膜与自组装膜法制备电化学DNA传感器的研究进展

介绍了DNA电化学生物传感器的研究现状、原理和结构,对DNA探针固定(尤其是聚合物与自组装膜法固定DNA)以及应用方面的最新研究进展进行了综述。     

α，α′－二乙酰基二苄硫基缩烯酮的晶体结构

用Ｘ射线衍射法测定了标题化合物Ｃ_（２０）Ｇ_（２０）Ｏ_２Ｓ_２的晶体结构。该晶体属单斜晶体，空间群为Ｃ_２／Ｃ，晶胞参数α＝１．１５０４（２）ｎｍ，ｂ＝１．１７８１（２）ｎｍ，ｃ＝１．４４４３（３）ｎｍ，β＝１０１．１４（３）°；Ｖ＝１．９２０６（７）ｎｍ~３，ｚ＝４，Ｄ_ｘ＝１．２３３ｍｇ／ｍｍ~３，Ｆ（０００）＝７５２．最终偏离因子Ｒ＝０．０４３６．化合物中碳氧双键键长为０．１１９３ｎｍ，碳碳双键（Ｃ（１）－Ｃ（２））键长为０．１３３８ｎｍ，Ｓ－Ｃ_（ｓｐ）~２键键长为０．１７６２ｎｍ。     

4,4'-二（羟甲基）联苯的合成

以4,4'-二（氯甲基）联苯为原料,经水解生成苄醇类化合物4,4'-二（羟甲基）联苯。采用¹HNMR, IR, HPLC对产物进行了表征。研究讨论了反应条件、催化剂等因素对产物含量和收率的影响,并且优化了4,4'-二（羟甲基）联苯的合成工艺,提出了可能的催化反应机理。结果表明：聚乙二醇作为催化剂,可与溶液中的阳离子发生络合,增强了亲核试剂的反应活性,提高了反应速率。在优化工艺下反应12 h,粗产品HPLC含量可达97.2%,收率93.9%。     

基于气溶胶光学参数的拉曼激光雷达重叠因子校正方法

提出了一种稳定的拉曼激光雷达重叠因子计算和校正算法,适用于含有拉曼散射通道的激光雷达系统的重叠因子校正。此算法基于大气气溶胶光学参数的拉曼反演算法,通过分析消光系数和后向散射系数的反演特点,发现后向散射系数在过渡区中不受重叠因子的影响。用后向散射系数和激光雷达比的乘积对消光系数缺失信号进行初步校正,进而正演出初步校正后的拉曼散射回波信号,将实际拉曼散射回波信号与正演的拉曼散射回波信号相除即可得到重叠因子廓线。对回波信号和气溶胶光学参数进行了过渡区信号校正和盲区信号补充。分别用单组和连续的激光雷达实验观测数据进行了重叠因子的计算和校正,并与能见度仪观测的近地面数据进行了对比,呈现良好的一致性。结果表明,此算法对重叠因子计算较为稳定。     

A 10Gb/s Directly-Modulated 1.3μm InAs/GaAs Quantum-Dot Laser

We demonstrate 10 Gb/s directly-modulated 1.3 μm InAs quantum-dot （QD） lasers grown on GaAs substrates by molecular beam epitaxy. The active region of the QD lasers consists of five-stacked InAs QD layers. Ridge-waveguide lasers with a ridge width of 4 μm and a cavity length of 600 μm are fabricated with standard lithography and wet etching techniques. It is found that the lasers emit at 1293 nm with a very low threshold current of 5 mA at room temperature. Furthermore, clear eye-opening patterns under 10 Gb/s modulation rate at temperatures of up to 50oC are achieved by the QD lasers. The results presented here have important implications for realizing low-cost, low-power-consumption, and high-speed light sources for next-generation communication systems.     

食品中氨基甲酸酯农药残留的分析方法

综述了近年来食品中氨基甲酸酯农药残留的分析方法。分别对样品预处理、色谱检测方法以及近年来发展起来的新技术,如超临界流体色谱、色质联用及一些非色谱技术如免疫检测、生物传感器等进行了讨论,并对农残检测的发展前景进行了展望。