Preparation and characterization of PEGDE crosslinked silk fibroin film

To obtain water-insoluble silk fibroin(SF) materials, polyethylene glycol diglycidyl ether(PEG-DE) was selected as a crosslinking agent to prepare SF films(blends). The reaction conditions were optimized for the crosslinking of the SF molecules. The hot water stability of the blends was measured using BCA protein assay and gravimetric analysis. The molecular conformation and crystalline structure of the blends were analyzed by FTIR and XRD, respectively. When the mass ratio of SF:PEG-DE was 1.0:0.8, the hot water loss rate of the SF blends was minimized. PEG-DE could induce SF molecules to form β-sheets during the gel reaction process, resulting in improved crystallinity and hot water dissolved resistance of the blend films. In order to demonstrate the cytotoxicity of the chemical reagents used to crosslink SF, L929 cells were seeded on the blend film(SF:PEG-DE = 1:1) and cultured for 3 days. Cells of L929 readily adhered and spread in the fusiform on the blend film resulting in high cell viability. The extracted liquid from the SF porous film did not inhibit cell proliferation, as estimated by the MTT assay.     

纳米TiO2碳热氮化制备纳米晶Ti(C0.7,N0.3)固溶体

在封闭系统中,对纳米TiO2碳热还原氮化反应合成纳米晶Ti(C,N)固溶体粉末进行研究。结果表明,当以C/Ti值为2.7配料,氮气压力为0.005 MPa时,一定量纳米TiO2/纳米碳黑混合料在1600℃下保温4 h,可以合成晶粒尺寸为32 nm的球形Ti(C0.7,N0.3)固溶体粉末。     

电铸金刚石-镍复合膜微观应力分析

用电铸方法，采用低应力电镀液，研制出了金刚石-金属复合膜。该复合膜的厚度为20-45μm，可用于制作超薄切割刀具。介绍了用X射线衍射法（xRD）测量多晶体微观应力的基本原理和用X射线衍射法测量镍多晶体显微应变的程序。用单波法计算了电铸金刚石-镍复合膜的显微应变，并用扫描电镜（SEM）观察了该复合膜的表面形貌。结果发现：阴极电流密度严重影响复合膜的显微应变，在实验所用电流密度范围内（0．6-3．5A／dm^2），随着电流密度的增加，显微应变减小。     

Influence of chromium on the local structure and morphology of ferric oxyhydroxides

The extended X-ray absorption fine structure (EXAFS) method and transmission electron microscopy (TEM) have been used for characterizing the local structure and morphology of ferric oxyhydroxides, α-FeOOH and γ-FeOOH, with and without chromium. These ferric oxyhydroxide powders were prepared from aqueous solutions containing iron and chromium ions. Radial structural functions for iron obtained by Fe K edge EXAFS spectra showed that the linkage of structural units formed by FeO₆ octahedra in γ-FeOOH is distorted by chromium addition, while such distortion in α-FeOOH is not clearly detected. On the other hand, Cr K edge EXAFS spectra showed that the local structure around chromium does not necessarily correspond to the local structure around of iron, which is observed by Fe K edge EXAFS spectra. This suggests that the structural units containing iron and chromium are heterogeneously distributed in these ferric oxyhydroxides. The local structural information was discussed coupled with morphological features of these ferric oxyhydroxides observed by TEM.     

基于XRD的薄膜界面结合强度试验研究

利用X射线衍射技术（XRD）分析了薄膜结合界面应力及其变化规律，通过对薄膜界面结合状态的检测，建立了X衍射法测量薄膜界面结合强度的原理、方法与过程。其检测界面结合强度方法可对薄膜试样进行非接触检测，适用于晶体或多晶体薄膜的界面结合强度测量，是一种研究无损检测薄膜结合强度的试验新方法。     

Evolution of patinas on copper exposed in a suburban area

Copper plates were exposed under sheltered outdoor conditions for up to one year, starting in September 2001 in Musashino City, Tokyo, a suburban area. Following various periods of exposure, the patinas on the plates were characterized to investigate their evolution by using X-ray fluorescence analysis, X-ray diffraction, field emission scanning electron microscopy, and glow discharge optical emission spectroscopy. The difference in the roles of sulfur and chlorine in the early stages of copper patination were identified by analyzing the depth profiles of these two elements. Sulfur was found on top of the patina as cupric sulfates such as posnjakite (Cu₄SO₄(OH)₆ · H₂O) or brochantite (Cu₄SO₄(OH)₆). Brochantite appeared only after 12 months of exposure. In contrast, chlorine was found on the surface after only one month of exposure. It gradually penetrated the patina as the exposure period lengthened, forming copper chloride complexes. Chloride ions accumulated at the patina/copper interface, forming nantokite (CuCl), which promoted corrosion.     

High temperature corrosion mechanisms and effect of alloying elements for materials used in waste incineration environment

Corrosion products on two typical materials, SA213-T12 steel and alloy 625 exposed to the actual combustion gas, were analyzed in addition to laboratory tests for penetration of corrosive matter. It has been clarified that corrosion products of oxides containing a little chlorides and sulphides show lamellar structures and that at the alloy-scale interface, chlorination, sulphidation, and oxidation occur under a low P_O2-high P_Cl2 condition. The formation of scale structures and the effect of corrosion-resistant alloying elements can be explained according to the stability tendencies of metals, chlorides, and oxides in the M-Cl-O equilibrium diagrams. The severity of corrosion environments at the interface is influenced by the penetration extent of corrosive matters through deposits and scales, and the protective effects of oxide films derived from alloying elements play an important role in preventing the corrosion. On the other hand, it has been shown that thermal fluctuation characterized in this kind of environment makes the lamellar scale structures and sometimes breaks and peels off the scale, and thus accelerates the corrosion. On the basis of the above mentioned knowledge, a new corrosion model is presented.     

Differences between corrosion products formed on copper exposed in Tokyo in summer and winter

We analyzed the copper corrosion products that formed during a month in summer and a month in winter at three sites in Tokyo using several analytical techniques. The X-ray diffraction patterns revealed that cuprite Cu₂O and posnjakite Cu₄SO₄(OH)₆·H₂O formed on copper exposed in summer. By contrast, only cuprite was found in winter exposed copper. The X-ray fluorescence results indicated that the amounts of sulfur and chlorine on the copper plates exposed in summer were much greater than those in winter. This could be explained by the change in particulate sulfate and sea salt concentrations. Depth profiling analysis by Auger electron spectroscopy revealed that the oxide layer formed in summer was thicker than that in winter. This difference in oxide layer thickness could have been due to the differences in temperature, relative humidity, and the amount of sulfur and chlorine on the copper plate.     

有机大阳离子与HnXW12O40·nH2O（X=B，Si，P）多金属氧酸盐的合成及热行为

合成了3种新的多金属氧酸盐(CTMA)5BW12O40·8H2O,(CTMA)4SiW12O40·3H2O,(CTMA)3PW12O40·2H2O,利用元素分析、IR光谱和TG-DTA技术对其进行了表征.IR光谱表明这些化合物不仅含有Keggin型结构,而且存在有机大阳离子的特征吸收峰;TG-DTA曲线显示它们的热行为是一个多步分解过程,首先这些化合物在大约269℃以下脱去水分子,然后它们的无水多金属氧酸盐经历了两步或3步的分解过程,分别脱去CTMA分子及其碎片,并伴随Keggin型结构的塌陷.通过XRD和IR光谱确证其最终分解产物是一个含有WO3与B2O3,SiO2或P2O5的混合物.同时还提出了这些化合物可能的热分解过程.     

Mechanical activation-assisted electro-thermal explosion synthesis of the Ti2AlC phase

This study deals with the synthesis of the Ti₂AlC phase using the Electro-Thermal Explosion under Pressure with Confinement (ETEPC) technique. The effects of the ETEPC technique and the milling process parameters on the TiC_x phase content and the formation mechanism of the Ti₂AlC phase were investigated. The latter is mainly affected by the morphology of the powder mixture and aluminum melted amount. The optimization of the above parameters allowed the achievement of the desired reaction, leading to the formation of the Ti₂AlC phase with a purity of about 97?wt%. The results clearly demonstrate that the ETEPC process enables one to control both time and material synthesis temperature.