Kinetics of H→P cross-polarization in human trabecular bone

Bloch-decay and cross-polarization (CP) ³¹P nuclear magnetic resonance (NMR) spectra of healthy human trabecular bone were acquired under magic-angle spinning (MAS) at 3 kHz. A single peak at 3.1 ppm was detected. Variable-contact time ¹H → ³¹P CP experiments revealed three signal components growing at various rates. The fast, moderate and slow components were assigned and assessed in P atom % to proton-rich (24%), hydroxyapatite (58%) and proton-deficient (18%) phosphate domains, respectively. Examination of CP kinetics is useful for the chemical characterization of bone tissue.     

On Ions Transport during Drying in a Porous Medium

Salt crystallisation at the surface or in a porous medium has been recognised as a major mechanism of deterioration of buildings and historical monuments. Often crystallisation occurs when the concentration of salt dissolved in the water contained in the porous medium reaches the saturation concentration as the result of evaporation. In order to predict the evolution of the ion distribution during drying, we develop a simple volume averaged model combining a semi-analytical model of drying with the numerical computation of the ions transport. The model is used to analyse the influence of the drying rate, size of the porous medium, average pore size and initial ion concentration on the ion distribution during drying and therefore the possible location of crystallisation.     

三足苯甲酰基硫脲类离子受体的合成及识别性能

本文设计并合成了两种新型含酰基硫脲结构单元的三足受体1和2,并对其结构进行了表征确证。研究表明该类受体化合物对F^-、Ac^-和CN-表现出良好的紫外识别能力,由于受体1分子内电荷转移作用较强,故对阴离子表现出裸眼识别性能。紫外滴定表明,该类化合物对F^-和CN^-具有更好的结合能力;核磁滴定表明,阴离子通过分子间氢键与受体化合物结合形成主客体配合物,在高浓度F^-时受体化合物发生脱质子行为。此外,该类化合物对Hg^2+具有一定的荧光选择性识别能力。     

荧光法研究恩诺沙星与牛血清白蛋白的结合作用

应用荧光光谱法、吸光光度法研究了生理条件下(pH=7.4)恩诺沙星(ENR)与牛血清白蛋白(BSA)的相互作用.实验表明,ENR对BSA内源性荧光的猝灭机制属于形成了复合物的单一静态猝灭过程,其结合常数为2.60×105 L·mol-1,结合位点数为1.07.根据Forster非辐射能量转移理论,计算出恩诺沙星与BSA结合位置距色氨酸残基的距离为 2.57 nm.能量转移效率为0.279.此外,探讨了共存Cu (Ⅱ)、Zn (Ⅱ)对药物与血清白蛋白结合作用的影响.     

How To Tame Planar and Main Group Metal-Substituted Onium Ions of Phosphorus and Arsenic

The P + -transfer abilities of 1,1,1,3,3,3-hexakis(dimethylamino)-triphosphenium tetraphenylborate were investigated. Reaction with Schwartz reagent lead to the first planar tetracoordinated phosphonium salt P[ZrCp 2 H] 4 + BPh 4 + . The theoretical background of this unusual planar geometry at the phosphorus atom is discussed. The first arsenic analogue [As(P(NMe 2 ) 3 )2] + BPh 4 m of the respective triphosphenium salt was prepared, which surprisingly can act as a P + - and As + -transfer reagent at the same time. Furthermore, the synthesis of perstannylated ([(Me 3 Sn) 4 E]OSO 2 CF 3 , E = N, P) and persilylated ([(Me 3 Si) 4 E] + B(C 6 F 5 ) 4 m , E = P, As) onium ions of nitrogen, phosphorus, and arsenic are reported, which are potential starting materials for an independent access to E[ZrCp 2 X] 4 salts.     

二氧化硅吸附铝离子的X射线光电子能谱(XPS)表征

用X射线光电子能谱技术研究了不同pH条件下二氧化硅对铝离子的吸附作用。在pH分别为3.74、4.25和4.88条件下,吸附在二氧化硅表面的铝离子的Al2p电子结合能依次为74.30、74.90、75.10eV。根据Al3 在水溶液中的一级水解常数pK1=4.99,认为在pH=3.74条件下,吸附在二氧化硅表面的铝离子的形态为Al3 ,而在其余两种pH条件下表面铝离子的形态为Al(OH)2 。     

钙钛矿/银电极界面降解和离子迁移的原位研究

本文对CH_3NH_3PbI_3钙钛矿层与Ag电极之间的界面降解和离子迁移过程进行了全面地研究.利用原位光电子能谱检测于段,发现了Ag电极会诱导钙钛矿层的降解,导致PbI_2和AgI物种的形成以及Pb~(2+)离子在界面处还原成金属Pb物种.I 3d谱峰强度的反常增强为碘离子从CH_3NH_3PbI_3下表面迁移到Ag电极提供了直接的实验证据.此外,Ag电极和钙钛矿层接触会在CH_3NH_3PbI_3/Ag界面处诱导0.3 eV的界面偶极,这可能进一步促进碘离子扩散迁移,导致钙钛矿层的分解和Ag电极的侵蚀.     

Thin-film analysis by 100 keV proton beam

Summary 100 keV proton beams have been used for measuring thickness, implanted doses, ion-mixing process and sputtering yield in thin films. The method potentiality and the possibility to executein situ measurements are shown. Calibration methods, based on proton-induced X-ray emission, have been determined by using Rutherford backscattering analysis.

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Riassunto Fasci di protoni a bassa energia (100 keV) sono stati adoperati per eseguire misure di spessori di film sottili, misurein situ di dosi impiantate, studio di processi di mescolamento di ioni e determinazioniin situ di fattori di sputtering di diversi materiali. Il lavoro si propone di mostrare le capacità del metodo e la possibilità di poter eseguire misurein situ. La calibrazione dei vari metodi di analisi, basati sulla fluorescenza X indotta dal fascio di protoni incidente, è stata eseguita comparandone i risultati con quelli ottenuti dalla tradizionale tecnica del Rutherford backscattering.

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Резюме Пучки протонов с энергий 100 кэВ используются для измерения толщины, дозы имплантации, процесса смешивания ионов и выхода распыления в тонких пленках. Обсуждаются возможности метода. Методы градуировки, основанные на рентгеновском излучении, индуцированном протонами, детерминируются с помощью анализа обратного резерфордовского рассеяния.

     

原子簇离子产生的动力学方程与分布函数

由激光等离子体反应产生的原子簇分子与离子，经历了分子-离子反应的过程．本文尝试将Smoluchowski方程加以扩展，用于描述原子簇离子的生成过程．通过应用解析方法，求解不可逆聚合过程的动力学方程，推导出了原子簇离子统计分布的函数关系式，证实了实验中观察到的原子簇的统计分布规律．     

稀土元素在玻璃和石英及塑料容器内壁上吸附研究

用原子发射光谱法，对不同浓度的硝酸或盐酸溶液中微量稀土离子在不同容器材料内壁上的吸附行为进行研究。结果表明，稀土元素在试验酸浓度范围内（0．13.0mol.L^-1)，酸浓度越高，吸附量越少，在所选择的3种材料中，石英材料上的吸附量最少，其次是玻璃，吸附量最多的是塑料；对于相同浓度的盐酸和硝酸，吸附量相近。