One‐Dimensional Spin Chains from CuII Ions and 2,5‐Bis(pyrazol‐1‐yl)‐1,4‐dihydroxybenzene

The purple colored coordination polymer [1 Cu]_n was obtained from 2,5‐bis(pyrazol‐1‐yl)‐1,4‐dihydroxybenzene and CuBr₂ in aqueous ammonia. The crystal structure of [1 Cu]_n was determined from high resolution X‐ray powder diffraction data using the method of simulated annealing. In the solid state, [1 Cu]_n features largely independent linear chains, all of them being oriented parallel to the c‐axis of the crystal. The Cu ions are coordinated in a square‐planar fashion by two nitrogen atoms and two anionic oxygen donors. Magnetic susceptibility and magnetization measurements indicate the Cu ions in [1 Cu]_n to be antiferromagnetically coupled with a coupling constant of about 20 K.     

Iod‐katalysierte Herstellung von intermetallischen Verbindungen der Edelmetalle: Die Kristallstrukturen von BePd2 und BePd3

Iodine‐Catalyzed Production of Noble Metal‐Rich Intermetallics: The Crystal Structures of BePd₂ and BePd₃ The two Pd‐richest phases of the Be—Pd system are accessible 400 °C below the eutectic temperature within 48 h through an iodine‐catalyzed reaction of the metals. The crystal structures of BePd₂ and BePd₃ have been determined by means of X‐ray powder diffractometry. BePd₃ is isotypic to BRe₃. BePd₂ adopts a MoSi₂ type related structure.     

Synthesis,spectroscopic characterization and Antibacterial screening of some new cefotaxime sodium derivatives

Biologically active compounds with heteroaromatic ring system of cefotaxime sodium have been synthesized via aminomethylation reaction. The aminomethylation of cefotaxime sodium with various biologically potent sulphonamides/secondary amines was carried out and then characterized by elemental analysis and spectral studies – IR, ¹H NMR, ¹³C NMR, Powder X-ray diffraction and Scanning Electron Microscopy. The compounds were screened for their antibacterial activity against various pathogenic bacteria at varying concentrations. The antibacterial activity of cefotaxime sodium derivatives was compared with parent sulphonamides. The toxicity of synthesized cefotaxime sodium derivatives was ascertained by LD₅₀ test.     

ICP-MS测定章松八味沉香散中的微量元素

采用电感耦合等离子体-质谱法（ICP-MS）分析藏药章松八味沉香散中铬、钴、铜、锰、锌、钼、铁、镍等8种微量元素的含量,其中铁、铜、镍、锰含量较高,其他元素含量较低,藏药章松八味沉香散中元素的分布特点与章松八味沉香散具有消心热、宁心安神、行气降压之功效有关,为现代用药提供了参考数据。     

Magnetic and structural properties of NaLnMnWO6 and NaLnMgWO6 perovskites

We have prepared 14 new AA′BB′O₆ perovskites which possess a rock salt ordering of the B-site cations and a layered ordering of the A-site cations. The compositions obtained are NaLnMnWO₆ (Ln=Ce, Pr, Sm, Gd, Dy, and Ho) and NaLnMgWO₆ (Ln=Ce, Pr, Sm, Eu, Gd, Tb, Dy, and Ho). The samples were structurally characterized by powder X-ray diffraction which has revealed metrically tetragonal lattice parameters for compositions with Ln=Ce, Pr and monoclinic symmetry for compositions with smaller lanthanides. Magnetic susceptibility vs. temperature measurements have found that all six NaLnMnWO₆ compounds undergo antiferromagnetic ordering at temperatures between 10 and 13 K. Several compounds show signs of a second magnetic phase transition. One sample, NaPrMnWO₆, appears to pass through at least three magnetic phase transitions within a narrow temperature range. All eight NaLnMgWO₆ compounds remain paramagnetic down to 2 K revealing that the ordering of the Ln³⁺ cations in the NaLnMnWO₆ compounds is induced by the ordering of the Mn²⁺ sub-lattice.     

Synthesis and structure of the ternary and quaternary strontium nitride halides, Sr2N(X, X′) (X, X′=Cl, Br, I)

A number of new, layered nitride mixed halides have been synthesised in the quaternary phase systems Sr-N-Cl-Br and Sr-N-Br-I. The variation in structure with composition has been investigated by powder X-ray and powder neutron diffraction techniques and the structure of strontium nitride iodide, Sr₂NI, has been determined for the first time (rhombohedral space group R-3m, , , Z=3). A continuous solid solution exists between Sr₂NCl and Sr₂NBr with intermediate compounds adopting the same anti-α-NaFeO₂ structure (rhombohedral space group R-3m) as the ternary end members. A similar smooth and linear relationship between structure and composition is seen from Sr₂NBr to Sr₂NI and hence cubic close packing of metal-nitrogen layers is adopted regardless of halide, X (X′). While nitride and halide anions occupy distinct crystallographic sites, there is no ordering of the halides in the quaternary materials irrespective of stoichiometry or temperature (between 3 and 673 K).     

The non-centrosymmetric borate oxides, MBi2B2O7 (M=Ca, Sr)

Two novel noncentrosymmetric borates oxides, MBi₂B₂O₇ or MBi₂O(BO₃)₂ (MCa, Sr), have been synthesized by solid-state reactions in air at temperatures in the 600-700 °C range. Their crystal structures have been determined ab initio and refined using powder neutron diffraction data. CaBi₂B₂O₇ crystallizes in the orthorhombic Pna2₁ space group with a=8.9371(5) Å, b=5.4771(3) Å, c=12.5912(7) Å, Z=4, R_wp=0.118, χ²=2.30. SrBi₂B₂O₇ crystallizes in the hexagonal P6₃ space group with a=9.1404(4) Å, c=13.0808(6) Å, Z=6, R_wp=0.115, χ²=4.15. Large displacement parameters suggest the presence of disorder in SrBi₂B₂O₇ as also revealed by diffuse 2×a superstructure reflections in electron diffraction patterns. Both structures are built of identical (001) neutral layers of corner-sharing BO₃ triangles and MO₆ trigonal prisms forming six-membered rings in which Bi₂O groups are located. Adjacent layers are stacked in a staggered configuration and connected through weak Bi-O bonds. A moderate efficiency for second harmonic generation (SHG) has been measured for a powder sample of CaBi₂B₂O₇ (d_eff=2d_eff(KDP)).     

Dissolution and reconstitution of casein micelle containing dairy powders by high shear using ultrasonic and physical methods

The effect of shear on the solubilization of a range of dairy powders was investigated. The rate of solubilization of low solubility milk protein concentrate and micellar casein powders was examined during ultrasonication, high pressure homogenization and high-shear rotor–stator mixing and compared to low-shear overhead stirring. The high shear techniques were able to greatly accelerate the solubilization of these powders by physically breaking apart the powder agglomerates and accelerating the release of individual casein micelles into solution. This was achieved without affecting the structure of the solubilized proteins. The effect of high shear on the re-establishment of the mineral balance between the casein micelles and the serum was examined by monitoring the pH of the reconstituted skim milk powder after prior exposure to ultrasonication. Only minor differences in the re-equilibration of the pH were observed after sonication for up to 3 min, suggesting that the localized high shear forces exerted by sonication did not significantly affect the mass transfer of minerals from within the casein micelles.     

X射线荧光光谱分析中的粉末压片制样法

本文是一篇关于XRF光谱分析中粉末压片制样法的综述。根据70多篇文献和一些常见的资料，作者从样品制备、方法应用、理论校正等三个方面介绍了粉末压片制样法的现状和进展。