用X光射线衍射法定量分析碳化硅砖的矿物组成

X光射线衍射法是定性定量分析、检测耐火材料矿物组成中同质异象、多晶转变等准确简便的方法 ,而且它可以完成光学显微镜和图像分析仪等因晶粒太小或在灰度上难以区别等不能定量工作的一些问题。在这种情况下 ,用X光射线衍射法既不损坏物质原有的矿物结构 。

Preparations of Complex Bimetallic Oxides from Bimetallic Assemblies Containing Different Copper（Ⅱ） Precursors and Comparison of Some Related Systems

This is a mini-review-like article including our recent results and methods for （new） metal oxides and （previously reported） composite materials composed of metal complexes and metal oxides for comparison to enhance anisotropic structural changes intentionally. Some complex inorganic oxides are known that they may be promising color materials （absorbing visible light of certain wavelengths region） having potential application for environmentally benign catalysts, for example, photocatalysts. Chiral copper（Ⅱ） complexes having bidentate amine ligands （[CuL2]2＋） can be acted as cationic building blocks of bimetallic metal complexes. We have prepared some chiral bimetallic complexes with various anionic metal complexes such as [PtCl4]2-, [M02O7]2 and Mn12 clusters （typical single-molecule magnets） which characterized by means of solid-state electronic and CD （circular dichroism） spectra, IR （infrared） spectra, synchrotron XRD （X-ray diffraction） and XAS （soft X-ray absorption spectroscopy）. By sintering these precursor chiral bimetallic complexes, we have prepared complex inorganic oxides from them. The IR spectra indicated substituting metal-ligand bonds and losing organic moieties. The XRD pattern indicated complete changes of crystal structures. The XAS revealed replacing coordination atoms as well as oxidation of valences of metal ions. Furthermore, we will also investigate possibility of patterning by homogeneous precipitation method as bimetallic complexes to prepare desirable complex inorganic oxides.

Preparation and Characterization of High Purity Enriched 10B Boric Acid via Anti-Solvent Recrystallization

Self-made enriched IUB boric acid as raw material was purified by recrystallization. The effects of final crystallization temperature, crystallization time, stirring speed, crystallization frequency and other factors on the purity were investigated. The appropriate operating condition was that the final crystallization temperature and time were 5 ℃ and 10 h respectively under a low-speed stirring for crystallizing twice, which would make the purity and yield of boric acid reach 99.94% and 95.36%, respectively. Taking this as foundation, recrystallization process was optimized with acetone as anti-solvent, whose amount was the most important index. The boric acid solution was added into acetone and recrystallized under the same condition, and the purity and yield of boric acid would reach 99.98% and 99.61%, respectively. The product detected by XRD was confirmed as boric acid crystal. Main ion concentration in the product was detected by ICP, which basically met the national standard of high purity. Crystal morphology of boric acid was observed by SEM.

Molecular Fundaments of Mechanical Properties of Spider Silk

Dragline,framework and cocoon silk fibers of Araneus Ventricosus were used for this study.To investigate the microstructure mechanisms of stress-strain behavior of spider silk,firstly,amino acid compositions were analyzed and molecular conformations and crystallinity were measured with Raman spectra and X-ray diffraction respectively.The results showed that there were more amino acids with large side groups and polar ones in spider silk than those of Bombyx silk,and the amino acid distribution varied with different spider silk.The molecular structures were mainly α-helix and β-sheet,and random coil and β-turn existed as well.The proportions and arrangement of these conformations of dragline silk were different from framework and cocoon silk fibers.Microstructure was one of important factors of excellent mechanical properties of spider silk.Crystallinity of spider silk was very low,which implied that the roles of crystal on spider silk were not as great as other protein fibers.

Study on the Influence of Ni Modifying on Phase Transformation and Photocatalytic Activity of TiO_2

The Ni-modified TiO2 was synthesized using two methods including co-precipitation(Ni doped TiO2, Ni-TiO2) and wet impregnation(Ni loaded TiO2, Ni/TiO2). The surface and bulk crystalline phases of Ni-modified TiO2 were investigated by using X-ray diffractometry(XRD), UV Raman spectroscopy, TEM, and SEM. It is observed that Ni doping can promote the phase transition and grain size growth of TiO2. Moreover, the propagation of the rutile phase from the bulk into the surface region of TiO2 is increased when the Ni doping amount reaches up to 3%. However, in Ni/TiO2, it is found out that the surface and bulk phase transformation of TiO2 can be inhibited after impregnation of 1% of Ni on the TiO2. Compared with the co-precipitation method, Ni species may be more enriched in the surface of the Ni/TiO2 sample upon adoption of the impregnation method, and the direct contact of anatase particles of TiO2 is avoided. As a consequence, the phase transition in the surface and bulk region of TiO2 can be effectively inhibited by Ni loading. Additionally, the activity of the photocatalytic degradation of RhB on the 3Ni-TiO2-600 ℃ sample is higher than that on the 3 Ni/TiO2-600 ℃ sample. The phase junction formed between anatase and rutile in the surface region of 3Ni-TiO2-600 ℃ may the main reason for its high photocatalytic activity.

Mg and Ni Incorporated ZnO Diluted Magnetic Semiconductor for Magnetic and Photo-Catalytic Applications

Zinc oxide is recently being used as a magnetic semiconductor with the introduction of mag-netic elements.In this work,we report phase pure synthesis of Mg and Ni co-substituted ZnO to explore its structure,optical,magnetic and photo-catalytic properties.X-ray di raction analysis reveals the hexagonal wurtzite type structure having P63mc space group without any impurity phase.UV-Vis spectrophotometry demonstrates the variation in bandgap with the addition of Mg and Ni content in ZnO matrix.Magnetic measurements exhibit a clear boosted magnetization in Ni and Mg co-doped compositions with its stable value of bandgap corroborating the structural stability and magnetic tuning for its advanced applications in modern-day spintronic devices.Photo-catalytic measurements performed using methyl green degradation demonstrate an enhanced trend of activity in Mg and Ni co-doped compositions.

Surface Na2CO3 etching induced activity enhancement of 2D BiOI photocatalyst working under visible light

The visible light photocatalytic activity of two-dimensional （2D） BiOl microplates was intensively enhanced through simply dipping in Na2CO3 solutions at room temperature. The X-ray powder diffrac- tion （XRD） and scanning electron microscopy （SEM） investigations suggest that little amount of （BiO）2CO3 phase was formed on the surface of 2D BiOI via the in situ chemical conversion. The concen- tration of Na2CO3 solutions affected the structure, morphology, light absorption and surface element component of 2D BiOl. The surface loaded （BiO）2CO3 mainly trapped the photoinduced electrons of BiOI, improved the separation efficiency of photocharges and finally raised the photocatalytic activity of BiOl under visible light （λ 〉 420 nm）. Furthermore, the product of the as-prepared （BiO）2CO3/BiOI displayed excellent stability in the repeated experiment. This study provides a facile way to improve the photocatalytic activity of BiOX （X = CI, Br, I） by means of surface treatment with Na2CO3 solutions.

Green and low temperature synthesis of nanocrystalline transition metal ferrites by simple wet chemistry routes

Crystalline and nanostructured cobalt （CoFe2O4）, nickel （NiFe2O4）, zinc （ZnFe2O4） and manganese （MnFe2O4） spinel ferrites are synthesized with high yields, crystallinity and purity through an easy, quick, reproducible and low-temperature hydrothermal assisted route starting from an aqueous suspension of copredpitated metal oxalates. The use of water as a reaction medium is a further advantage of the chosen protocol. Additionally, the zinc spinel is also prepared through an alternative route combining copredpitation of oxalates from an aqueous solution with thermal decomposition under reflux conditions. The nanocrystalline powders are obtained as a pure crystalline phase already at the extremely low tem- perature of 75 ℃ and no further thermal treatment is needed. The structure and microstructure of the prepared materials is investigated by means of X-ray powder diffraction （XRPD）, while X-ray photoelectron spectroscopy （XPS） and inductively coupled plasma-atomic emission spectroscopy （ICP-AES） analyses are used to gain information about the surface and bulk composition of the samples, respectively, confirming the expected stoichiometry. To investigate the effect of the synthesis protocol on the morphology of the obtained ferrites, transmission electron microscopy （TEM） observations are performed on selected samples. The magnetic properties of the cobalt and manganese spinels are also investigated using a superconducting quantum device magnetometer （SQUID） revealing hard and soft ferrimagnetic behavior, respectively.