含铁化合物的Fe2p和Fe3s电子能谱研究

选择了十几种常见的含铁化合物,分另采集了它们的Fe2p和Fe3s谱。从峰位和峰形上讨论了它们各自的特点,结果表明Fe2p和Fe3s峰的峰形分析（如,shake-up卫星峰及多重分裂峰）像其结合能值一样可以提供化学状态分析的重要信息。     

Variability in the Formation and Framework Polymorphism of Metal-organic Frameworks based on Yttrium(III) and the Bifunctional Organic Linker 2,5-Dihydroxyterephthalic Acid

Depending on the solvothermal reaction conditions, we obtained three different metal-organic frameworks with yttrium(III) as metal component and 2,5-dihdyroxyterepthalic acid (H₄dhtp) as bifunctional organic linker: Y₂(H₂dhtp)₃(dmf)₄ · (dmf)₂ (CPO-29) contains dinuclear, paddle-wheel like inorganic secondary building units (SBUs) connected by the organic linker to a network with α-Po topology, while Y₂(H₂dhtp)(dhtp)(dmf)₂ (CPO-30) and Y₂(H₂dhtp)(dhtp)(dmf)₂(H₂O)₂ · (H₂O)₄ (CPO-31) contain one-dimensional inorganic SBUs that differ in how the half- and fully deprotonated ligands are connected to and arranged around them. Only the carboxylic acid groups of the organic linker are deprotonated in CPO-29, while CPO-30 and CPO-31 contain both 2,5-dihydroxyterephthalate (H₂dhtp^2–) linkers and fully deprotonated 2,5-dioxidoterephthalate (dhtp^4–) linkers. All three compounds contain large volumes filled with solvent, but we were able to demonstrate permanence of porosity only for CPO-30. Variable temperature powder X-ray diffraction reveals that CPO-29 and CPO-31 undergo discontinuous phase transitions upon heating, and the flexibility of the framework structure indicated by these might be the reason for the inability to access the pore volume. Desolvated CPO-30 and CPO-31 are polymorphs, whose network structures differ in whether the H₂dhtp^2– and dhtp^4– linkers are located in cis or trans arrangement around the inorganic SBU.     

Quantification of flupirtine maleate polymorphs using X-ray powder diffraction

Flupirtine maleate,a pharmaceutical compound for treating psychotic disease in clinics,has seven polymorphs.Form A,with better crystal stability and bioavailability,has been widely used as the pharmaceutical crystal form.Unfortunately,it is usually found in a polymorphic mixture with form B.In this study,pure crystal forms of A and B were prepared and characterized by X-ray powder diffraction (XRPD),Fourier transform infrared spectroscopy (FT-IR) and thermal analysis.An XRPD-based method for the quantitative determination of the amount of the flupirtine maleate polymorphs form A and form B was also established through a systematic optimization of instrumental parameters.The results of the analytical methodology validation showed that the XPRD method had a broad quantitative range of 0-100%(w/w),good linear relationship,with R²=0.999,excellent repeatability and precision and low limits of detection (LoD) of 0.15%(w/w) and quantification (LoQ) of 0.5%(w/w).The results also showed that the single-peak method was not as good as the whole pattern in reducing the influence of the preferred orientation,but this can be compensated for by a systematic optimization of instrumental parameters and validating the analytical methodology to reduce errors and obtain a good,repeatable,sensitive,and accurate method.This XRPD method can be used to analyze mixtures of flupirtine maleate polymorphs (forms A and B) quantitatively and control the quality of the bulk drug.     

DKDP晶体的柱面形貌与缺陷分析

采用原子力显微镜观测全方位生长的DKDP晶体的{100}面形貌,发现有螺旋位错,由此推断DKDP晶体{100}面以螺旋位错机制生长;利用同步辐射X射线白光形貌术观测了DKDP晶体缺陷,探讨了不同生长条件及生长阶段对晶体完整性的影响.     

Application of a synchrotron microprobe to the analytical characterization of ion-implanted material

A synchrotron microprobe has been used to characterize ion implantations of nickel and cobalt in silicon (100) or (111) wafers. The synchrotron radiation is collimated by means of a rigid cylindrical glass capillary of 110 mm length, 5 mm outer and 30 μm or 10 μm inner diameter. The beam is pointed at the wafer sample and the emitted radiation of X-rays is detected by an energy dispersive spectrometer. Line scans are recorded step by step over the implantation areas and across their borders. The sharpness of the borders is characterized at a lateral resolution of 13 μm and the edge lengths ranging from 0.6 to 8 mm are determined with an accuracy better than ± 20 μm. The signal intensity and implantation dose of cobalt ranging from 1 × 10¹⁵ to 1 × 10¹⁷ ions cm⁻² show a linear relationship as is to be expected for the micrometre thin implanted layers.     

Stereoisomeric Tris-BINOL-Menthol Bulky Monophosphites: Synthesis,Characterisation and Application in Rhodium-Catalysed Hydroformylation

Four stereoisomeric monoether derivatives, based on axially chiral (R)- or (S)-BINOL bearing a chiral (+)- or (−)-neomenthyloxy group were synthesised and fully characterised by NMR spectroscopy and X-ray crystallography. The respective tris-monophosphites were thereof prepared and fully characterised. The coordination ability of the new bulky phosphites with Rh(CO)₂(acac), was attested by ³¹P NMR, which presented a doublet in the range of δ = 120 ppm, with a ¹J(¹⁰³Rh-³¹P) coupling constant of 290 Hz. The new tris-binaphthyl phosphite ligands were further characterised by DFT computational methods, which allowed us to calculate an electronic (CEP) parameter of 2083.2 cm⁻¹ and an extremely large cone angle of 345°, decreasing to 265° upon coordination with a metal atom. Furthermore, the monophosphites were applied as ligands in rhodium-catalysed hydroformylation of styrene, leading to complete conversions in 4 h, 100% chemoselectivity for aldehydes and up to 98% iso-regioselectivity. The Rh(I)/phosphite catalytic system was also highly active and selective in the hydroformylation of disubstituted olefins, including (E)-prop-1-en-1-ylbenzene and prop-1-en-2-ylbenzene.     

Effect of heat treatment on the structure and morphology of ZnO nanorod array and its composite with titania precursor

ABSTRACT

Effects of the elevated temperature on the structure evolution of the ZnO nanorod array (ZNA) and their hybrid nanocomposite with layered (tetramethyl)ammonium titanate (LTMAT) prepared by the liquid phase deposition were investigated. The vertically oriented ZnO nanorods were deposited on a quartz plate by a chemical bath deposition method and then they were penetrated by the LTMAT using the dip-coating method from the water solution. As a result of such an experimental procedure, an assembly composed of the ZNA with LTMAT was obtained and called hybrid nanocomposite. Since the LTMAT converts to TiO₂ upon subsequent sintering at 350 °C, it can be regarded as TiO₂ precursor for the thermal treatment experiments. The experiments with ZNA and their hybrid nanocomposite at the elevated temperature revealed coalescence of the deposited ZnO nanorods and crystallization of zinc titanate with Zn₂TiO₄ stoichiometry.     

XRD,Raman and magnetic studies of Bi1−xLaxFeO3 solid solution obtained by mechanochemical synthesis

ABSTRACT

Bi_{1 ? x}La_xFeO₃ single-phase solid solution with 0 ≤ x ≤ 0.3 was obtained by mechanochemical synthesis and characterized by X-ray diffraction, FT NIR Raman spectroscopy and magnetic studies. The nanocrystalline powders of rhombohedrally distorted perovskite structure R3c were studied ‘as synthesized’ by mechanosynthesis and after annealing at 500 °C for 1 h. The annealing, which resulted in recrystallization of the amorphous shell of the nanograins, was found to modify the external lattice modes of Bi_1?xLa_xFeO₃ and resulted in changes in the temperature variation of the magnetization.     

Segregation of Pt at clean surfaces of (Pt, Ni)3Al

Experimental evidence for surface segregation of Pt at (1 1 1) surfaces of ternary (Pt, Ni)₃Al alloys is presented, based upon Auger electron spectroscopy, low energy ion scattering, and angle-resolved X-ray photoelectron spectroscopy. Density functional calculations in the dilute limit confirm that Pt segregation is energetically favored.     

Surface oxidation behavior of MgNd alloys

The oxidation kinetics of MgNd alloys oxidized in pure O₂ at high temperatures has been investigated. The results revealed two stages of the reaction: A fast initial oxidation was followed by a slow oxide growth with a parabolic kinetics. For MgNd alloys (Nd = 25 wt.%), the oxidation rate increased with the enhancement of the oxidation temperature. A sudden ignition was found for this alloys oxidized at 873 K up to about 80 min. Moreover, the increase of the Nd content would harm the oxidation resistance of the MgNd alloys. By Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis, it was found that a triplex structure of oxide film formed. The outer layer was composed of MgO, Nd₂O₃ and Nd(OH)₃, the middle layer mainly consisted of MgO and Nd₂O₃, and the inner layer was the transitional layer made of MgO, Nd₂O₃ and the content of the substrate. The protective oxidation was associated with the formation of the dense Nd₂O₃/MgO layer during isothermal oxidation process. The oxidation mechanisms for the formation of oxide film are discussed.