辐射烧蚀区电子温度研究

此文叙述了采用晶体谱仪测量辐射烧蚀区电子温度的方法.在"星光Ⅱ”激光装置上,以波长为0.35μm,能量～70J,脉宽～700ps的强激光注入辐射烧蚀靶,实验首次测到了辐射烧蚀样品自发射谱,配合理论计算,给出了碳氢样品电子温度29eV.另外用空间分辨晶体谱仪研究了发泡铝靶电子温度空间分布;用双示踪元素等电子谱线法研究了Formvar(CHO)膜平面靶的电子温度.     

Consecutive Single-Crystal-to-Single-Crystal Isomerization of Novel Octamolybdate Anions within a Microporous Hybrid Framework with Robust Water Sorption Properties

The 3D hybrid framework [{Cu(cyclam)}₃(κ-Mo₈O₂₇)] ⋅ 14H₂O ( 1 ) (cyclam=1,4,8,11-tetraazacyclotetradecane) undergoes sequential single-crystal-to-single-crystal transformations upon heating to afford two different anhydrous phases ( 2 a and 3 a ). These transitions modify the framework dimensionality and enable the isomerization of κ-octamolybdate (κ-Mo₈) anions into λ ( 2 a ) and μ ( 3 a ) forms through metal migration. Hydration of 3 a involves condensation of one water molecule to the cluster to afford the γ-Mo₈ isomer in 4 , which dehydrates back into 3 a through the 6 a intermediate. In contrast, 2 a reversibly hydrates to form 5 , exhibiting the same Mo₈ cluster as that of 1 . It is remarkable that three of the Mo₈ clusters (κ, λ and μ) are new and that up to three different microporous phases can be isolated from 1 ( 2 a , 3 a , and 6 a ). Water vapor sorption analyses show high recyclability and the highest uptake values for POM-based systems. The isotherms display an abrupt step at low humidity level desirable for humidity control devices or water harvesting in drylands.     

Tailored polymers by free radical processes

This paper describes a versatile and effective method for the control of free radical polymerization and its use in the preparation of narrow polydispersity polymers of various architectures. Living character is conferred to conventional free radical polymerization by the addition of a thiocarbonylthio compound of general structure S=C(Z)SR, for example, S=C(Ph)SC(CH₃)₂Ph. The mechanism involves Reversible Addition-Fragmentation chain Transfer and, for convenience of referral, we have designated it the RAFT polymerization. The process is compatible with a very wide range of monomers including functional monomers such as acrylic acid, hydroxyethyl methacrylate, and dimethylaminoethyl methacrylate. Examples of narrow polydispersity (≤1.2) homopolymers, copolymers, gradient copolymers, end-functional polymers, star polymers, A-B diblock and A-B-A triblock copolymers are presented.     

ChemInform Abstract: Stabilization of a Germanium—Oxygen Double Bond: A Theoretical Study.

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