CS2团簇增强的激光多价电离现象的质谱研究

利用脉宽为25ns的脉冲Nd:YAG 532 nm的激光,在8×1010W/cm2的强度下,用飞行时间质谱对CS2的激光电离过程进行了研究.观察到了较强的C2+和S2+高价离子信号,这些高价离子C2+,S2+的最可几平动能高达144eV,112 eV.不同进样方式,激光延迟以及束源压力的实验结果表明,这些高价离子可能来源于CS2团簇的库仑爆炸过程.多光子电离引发,逆韧致吸收加热-电子碰撞电离模型可能是高价离子产生的机理.     

双电层相互作用时胶体表面电位的分布及电荷密度的计算

本文以实验为基础,运用计算机数值解解出双电层相互作用时平面胶体表面电位ψ随距离X的分布,依据作者导出的双电层相互作用时胶体表面阴离子负吸附方程,计算出胶体表面外Hclmhotz面(OHP)处的表面电荷密度σ_δ;讨论了双电层相互作用程度(ψ_d/ψ_δ)对胶体表面电位分布及其表面电荷密度的影响。     

Helical nanocables with SiC core and SiO2 shell

A novel one-dimensional helical nanocable structure has been synthesized through the reaction of carbon fiber with SiO vapor. The crystalline SiC core typically has diameters of 10–20 nm with a helical periodicity of 30–40 nm and is covered by a uniform layer of 10–20 nm thick amorphous SiO₂. A growth mechanism is proposed on the basis of difference in the growth rate between crystalline SiC core and amorphous SiO₂ shell.     

Crystallographic report: Crystal structure of a homoleptic lanthanide guanidinate complex: [Ph2NC(NCy)2]3Yb·2PhCH3

The title complex, [Ph₂NC(NCy)₂]₃Yb·2PhCH₃ is a monomer with a six‐coordinate ytterbium center ligated by six nitrogen atoms of three chelating bidentate guanidinate ligands. The coordination geometry around the lanthanide ion is best described as a distorted trigonal prism. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis and characterization of A1 doped δ-laminar crystal sodium silicate

An modified laminar crystal sodium silicate(A1-SKS-6) was synthesized by spray drying and high temperature crystallization using sodium silicate as silicon source,Al atom as inorganic source and hexadecyltrimethy ammonium bromide(CTMAB) as the structure template.The hydrothermal stability of product was at least 1 h.The synthesized material was characterized by XRD and SEM.The results indicated that shape and intensity of XRD diffraction peak at 2θtook changes,but raw materialδphase crystal form kept unc...     

Construction of different supramolecular polymer systems by combining the host–guest and hydrogen‐bonding interactions

Poly(ethylene glycol) (PEG) can form either the inclusion complex with α‐cyclodextrins (α‐CDs) through host–guest interactions or the interpolymer complex with poly(acrylic acid) (PAA) through hydrogen‐bonding interaction. Mixing α‐CD, PEG, and PAA ternary components in an aqueous solution, the competition between host–guest and hydrogen‐bonding interactions occurs. Increasing feed ratio of α‐CD:EG:AA from 0:1:1 to 0.2:1:1 (molar ratio), various interesting supramolecular polymer systems, such as hydrogen‐bonding complex, dynamic polyrotaxane, crystalline inclusion complex, and thermoresponsive hydrogel, are successively obtained. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1114–1120, 2008     

Synthesis of a New Type of Amphilic and Water—soluble Tertiary Phosphine Ligands Substituted by an Ethoxylated Phosphonic Acid Chain and Their Palladium Complexes

The highly water-soluble phosphine ligands Na2O3PCH2CH2NH(CH2CH2O)nCH2CH2N-(CH2PPh)22(n=1,2,3) were prepared by a new and simple route under mild conditions in good yield; the palladium (Ⅱ） complexes of the ligands 3a-c with 2:1 or 4:1 -PPh2 to Pd^2 molar ratio were also prepared and characterized.     

长焦距光学系统杂光系数测试仪

报告了一种新的长焦距光学系统杂光系数测量装置,该装置除具有避免了制作大直径积分球的优点外,还能精确测量轴外杂光系数,分析各部分杂光源对杂光系数的影响.     

空间两维指向摆镜的成象分析

本文分析了航天摄影相机的指向摆镜统二轴摆动时的成家关系,讨论了摆镜引起的象倾斜及象倾斜角与摆镜摆角的关系,并论述了象倾斜的校正方法;本文还讨论了摆镜对地面的扫描轨迹和覆盖范围.     

大平面二极管虚阴极振荡器的宽脉冲微波辐射

给出了产生宽脉冲微波辐射的大平面天鹅绒二极管虚阴极振荡器的结构和测试装置，测得了二极管中阴－阳极等离子体的闭合速率为３０～４３ｋｍ／ｓ，获得了微波辐射的最大脉宽为１．５μｓ，产生的微波峰值功率约为１５ＭＷ，频率为０．５ＧＨＺ，指出这种平面二极管型虚阴极振荡器在辐射脉宽，辐射频率和辐射功率三者之间存在着物理上的制约关系，认为同轴型虚阴极振荡器是突破这种制约关系的一个新途径．