Spectroscopic and Structural Study of the 1：2 Aluminium（Ⅲ） Complex of Quercetin

Complex formation between aluminium and quercetin（Q） in methanol was investigated by means of 27^Al solid-state, 13^C and 1^H NMR and MS（ESI）, UV and IR spectra. Formation of the 1：2 complex was favored in methanol relative to all other solvent and the predominant species observed of Al（Ⅲ） has a 1：2 stoichiometry. The fine structure of 1：2 aluminum complex of quercetin was that the aluminum central atom chelated with two quereetin molecules and two methoxyl groups between two five membered rings, its coordination is six, the chelated site was 3-hydroxy-4-carbonyl.     

矩孔金属光栅矢量模式理论的数值计算

根据矩孔金属光栅的矢量模式理论，计算了不同入射方向，波长及偏振态情况下衍射场的分布，研究了不同光栅结构对衍射效率，偏振态变化的影响；同时，根据实际需要，加工制作了一批不同深度的矩孔光栅样品，进行了实验测量，并将计算值与实验值进行了比较，两者基本相符。     

The magnetic properties of Be-codoped GaMnN grown via molecular beam epitaxy

GaMnN and Be-codoped GaMnN were grown via molecular beam epitaxy using a single GaN precursor and their structural and magnetic properties were examined. X-ray diffraction and superconducting quantum interference device (SQUID) measurements revealed that the grown layers are homogeneous without precipitates. The saturation magnetization of GaMnN has increased from ∼4 to ∼16 emu/cm³ via codoping of Be. The d–d exchange interaction between Mn atoms was discussed for the ferromagnetism of GaMnN.     

Effect of γ-ray irradiation on the magnetic properties of NdFeB and Fe–Cr–Co permanent magnets

The effect of γ-ray irradiation on the magnetic properties of NdFeB and Fe–Cr–Co permanent magnets has been investigated. The magnetic flux loss of two kinds of magnets before and after irradiation was measured. Results show that the effect of γ-ray irradiation on the magnetic properties of sintered NdFeB is not so obvious as that on Fe–Cr–Co magnet. Irradiation-induced damage from γ-ray for the Fe–Cr–Co magnets was characterized for the first time. The decline of permanent magnetic properties of Fe–Cr–Co magnet induced by γ-ray irradiation is reversible except for the maximum energy product (BH)_max. The difference of coercivity mechanism between these two kinds of permanent magnets is responsible for the different dependence of magnetic properties loss induced by γ-ray irradiation.     

Urn模型的B网及其应用

Urn模型的离散概率分布被用于构造逼近格式,具有Bernstein多项式的许多特性。本文用B网技术对Urn模型概率分布给出新的解释,指出了Urn模型B网的诸多性质,导出分布函数曲线的导数公式,构造了Urn分布的对偶基及与此相关的拟插值算子。     

Difference in micellar properties of sodium dodecyl sulfonate from sodium 4-decyl naphthalene sulfonate in D2O solution studied by 1H NMR relaxation and 2D NOESY

¹H chemical shift changes of sodium 4-decyl naphthalene sulfonate (SDNS) at 313 K show that its critical micellar concentration lies between 0.82 and 0.92 mmol/dm³, which is in the same range as that of the previous study at 298 K. The spin–lattice relaxation time, spin–spin relaxation time and two-dimensional nuclear Overhauser enhancement spectroscopy experiments give information about the structure of the SDNS micelle and the dynamics of the molecules in the micelle. The size of the SDNS micelle remains almost unchanged in the temperature range from 298 to 313 K as deduced by analyzing the self-diffusion coefficient. Special arrangement of the naphthyl rings of SDNS in the micelles affects the packing of these hydrophobic chains. The methylene groups of the alkyl chain nearest the naphthalene groups penetrate into the aromatic region, which results in a more tightly packed hydrophobic micellar core than that of sodium dodecyl sulfonate.     

Speciation analysis of arsenic in traditional Chinese medicines by hydride generation-atomic fluorescence spectrometry.

A method has been described for the determination of arsenic species (arsenite and arsenate) by hydride generation-atomic fluorescence spectrometry (HG-AFS). The experimental conditions that influence the fluorescence intensity and the reduction of arsenic were investigated and optimized, and the influences from foreign ions and their elimination were studied. The detection limit was found to be 79.7 ng L(-1). The proposed method was applied to the determination of arsenic species in water leachate of traditional Chinese medicines with a recovery range of 91.1-109.5%.     

Synthesis of graft copolymers with “V‐shaped” and “Y‐shaped” side chains via controlled radical and anionic polymerizations

A combination of nitroxide‐mediated radical polymerization and living anionic polymerization was used to synthesize a series of well‐defined graft (co)polymers with “V‐shaped” and “Y‐shaped” branches. The polymer main chain is a copolymer of styrene and p‐chloromethylstyrene (PS‐co‐PCMS) prepared via nitroxide‐mediated radical polymerization. The V‐shaped branches were prepared through coupling reaction of polystyrene macromonomer, carrying 1,1‐diphenylethylene terminus, with polystyryllithium or polyisoprenyllithium. The Y‐shaped branches were prepared throughfurther polymerization initiated by the V‐shaped anions. The obtained branches, carrying a living anion at the middle (V‐shaped) or at the end of the third segment (Y‐shaped), were coupled in situ with pendent benzyl chloride of PS‐co‐PCMS to form the target graft (co)polymers. The purified graft (co)polymers were analyzed by size exclusion chromatography equipped with a multiangle light scattering detector and a viscometer. The result shows that the viscosities and radii of gyration of the branched polymers are remarkably smaller than those of linear polystyrene. In addition, V‐shaped product adopts a more compact conformation in dilute solution than the Y‐shaped analogy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4013–4025, 2007     

新型菲涅尔线聚焦聚光太阳电池组件研究

以聚甲基丙烯酸甲脂为材料,采用热压成型工艺加工成型线聚焦菲涅尔聚光透镜(8×),可用于空间、地面光伏系统太阳电池组件的聚光系统,并对在其聚光条件下,太阳电池的电流电压特性进行测试,结果表明,该菲涅尔线聚焦棱镜能有效提高太阳电池的单位输出功率.模具的机械加工精度和光学抛光精度低,是造成其部分聚光率损失的原因.