Studies on Natural CXN Zeolite： Modification, Framework De-alumination and Ion-exchange

A natural CXN zeolite (stilbite, type code-STI) discovered in China was modified with NH4^ exchange by using ammonium salt and calcinations (procedure Ⅰ), or with NH4 exchange followed by treatment with acid (procedure Ⅱ). The coordination state of Si and A1 atoms in the framework, the property of ion exchange, and the adsorption of the H-STI zeolite samples prepared by different modification procedure were investigated with XRD,EDX,^29Si and ^27Al MAS NMR, Ag^ ion exchange and Ne adsorption. The results of the investigations indicate that different procedure of the modification made variety on the distribution of the framework Si atoms and A1 atoms,the content of non-framework aluminum, and the blocking channels and the shielding effect to the positions of the exchangeable cations. The H-STI zeolite prepared by the procedure Ⅱ possesses high ion exchange capacity, open and perfect pore system, and high thermal stability.     

Ni的掺入对复合氧化物LaFeO3的结构及性质的影响

合成子Ｎｉ替代铁酸稀土复合氧化物ＬａＦ３１－ｘＮｉｘＯ３（ｘ＝０．１－０．６），对样品进行了ＸＲＤ、ＩＲ及Ｍｏｓｓｂａｕｅｒ谱测试，结果表明：ｘ＝０＼１，０＼２，０＼３的样品为正交相，ｘ＝０．５，０．６的样品为菱方相；伴随相结构从正交向菱方结构的转变，ＩＲ谱上Ｆｅ（Ｎｉ）－Ｏ键伸振动谱带向高频移动近２０ｃｍ＾－１，Ｍｏｓｓｂａｕｅｒ谱测试表明Ｆｅ均处于＋３自旋态，Ｎｉ离子以＋３价进入晶格。     

Synthesis and Crystal Structure of 〔P(CH_2Ph)Ph_3〕〔PdWS_4(S_2CNC_4H_8)〕

1INTRoDUCTIoNThiomolybdate(thiotungstate)isafundamentalunitoPsomemolybdenumen-zymesandplaysanimportantroleincoordinationchemistryasaligandforothermet-alstoformanalogouscompoundsofmetalloproteinst'3.Recentlyinterestingnonlinearoptical(NLO)propertieshavebeendiscoveredforthetypeofMo(W)-Cu(Ag)-Sclusterst2.33.Bythevarioussyntheticmethodsseveralhundredmixedmetalclustersandcomplexes,Mo(W)-M-S(M=transitionmetal),havebeensynthesizedt'i.AmongthesecompoundsthecasesofMbeingCu,Ag,Feareusualwhile…     

Novel Water Soluble Fluorescent Trimethine Indocyanines Containing N-ρ-Carboxybenzyl Group

Indocyanine dyes as fluorescent labeling reagents have been used in bioanalysis1,2. Arylsulfonate indocyanine dyes 1d and 1e developed by Waggoner A. S. et al.3,4 have excellent fluorescent properties combined with good aqueous solubility, are a new generation of fluorescent label compounds for proteins, oligonucleotides and other compounds containing hydroxyl, mercaptol or primary amine groups5. However, photostability of these dyes has been a problem. Z. G. YAO et al.6 reported that p…     

Effect of ligand structure of stationary phase of high performance hydrophobic interaction chromatography on renaturation efficiency of GuHCl-denaturedα-chymotrypsin

The renaturation of the denaturedα-chymotrypsin (α-Chy) with 1.7 mol·L-1 gua-nidine hydrochloride (GuHCI) by three kinds of stationary phase of high performance hydropho-bic interaction chromatography (STHIC) with a comparable hydrophobicity but different ligand structures was investigated. The obtained result indicates that the ligand structures of the three STHIC contribute to the renaturation efficiency ofα-Chy in the order of the end ligands PEG-600< phenyl group < tetrahydrofurfuryl alcohol (THFA).     

Preparation and characterization of dendrimer-star PNIPAAM using dithiobenzoate-terminated PPI dendrimer via RAFT polymerization

Two dendritic reversible addition-fragmentation transfer (RAFT) agents with 8 and 16 terminal dithiobenzoate (DTB) groups on the surface of poly(propylene imine) (PPI) dendrimers (generation 2.0 and 3.0, respectively) were successively prepared, and they were used in the RAFT polymerization of N-isopropylacrylamide (NIPAAM). The polymerization kinetics was confirmed to pseudo-first-order behavior. The ¹H NMR and GPC analyses show that the dendrimer-star den (NIPAAM)_x (x = 8 or 16) prepared by RAFT method has well-defined structure, controlled molecular weight and low polydispersities (PDI < 1.3). The aqueous solution prepared from dendrimer-star PNIPAAM showed reversible changes in optical properties: transparent below a lower critical solution temperature (LCST) and opaque above the LCST.     

Butterfly and Nest-Shaped Tp*-W-Cu-S Cluster Monomers and Dimers with Hexamethylenetetramine as Ligand: Anion-Dependent Structures and Nonlinear Optical Properties

The assembly of[Et4N][Tp*WS3](1) with CuX (Tp* =hydridotris(3,5-dimethylpyrazol-1-yl)borate;X =Cl,Br,and I) or[Cu(MeCN)4][PF6]in the presence of tetratopic liga...     

量子数字签名研究进展

量子数字签名是量子理论与经典数字签名的结合,其目的是利用量子效应达到无条件安全的信息交互。介绍了目前提出的几种量子数字签名协议,详细分析了这几种协议的优缺点和效率,提出了量子数字签名协议设计的具体要求,并展望了此领域今后的发展方向。     

Suppression of Phase and Amplitude Damping Decoherence in a Three-Level Atom in A-Configuration Using Bang-Bang Controls

In this paper, we present decoupling bang-bang operations for the suppression of general decoherence, both amplitude and phase damping, in a three-level system in A-configuration. We give a program to design a sequence of periodic twinborn pulses to suppress the decoherence in such the system.