Visible light responsive photocatalysts developed by substitution with metal cations aiming at artificial photosynthesis

To solve resource, energy, and environmental issues, development of sustainable clean energy system is strongly required. In recent years, hydrogen has been paid much attention to as a clean energy. Solar hydrogen production by water splitting using a photocatalyst as artificial photosynthesis is a promising method to solve these issues. Efficient utilization of visible light comprised of solar light is essential for practical use. Three strategies, i.e., doping, control of valence band, and formation of solid solution are often utilized as the useful methods to develop visible light responsive photocatalysts. This mini-review introduces the recent work on visible-light-driven photocatalysts developed by substitution with metal cations of those strategies.     

Effects of AIN Additions and Atmosphere on the Synthesis of Cubic Boron Nitride

Aluminum nitride was found to act as the catalyst for the synthesis of cubic BN by sealing the mixture of hexagonal BN and AIN in a pressure cell under the inert or reducing atmosphere. No conversion of hexagonal BN to cubic BN was observed under pressures below 7×10⁹ Pa (7 GPa, 70 kbar) without AIN addition. All hexagonal BN could be completely converted to cubic BN under 6.5 GPa at 1600°C by the addition of 20 mol% AIN. The cubic BN thus synthesized was a typical tetrahedron (grain size ≅2 μm). The pressure-temperature diagram for the synthesis of cubic BN was determined at >7 GPa and T <1700°C.     

TiO2 Produced by Vapor-Phase Oxygenolysis of TiCI4

The formation of TiO₂ powders by oxygenolysis of TiCI₄ was studied with emphasis on the effects of reaction conditions on the particle size of the products. The particle size of TiO₂(anatase) decreased with increasing reaction temperature or O₂concentration and with decreasing TiCI₄ concentration. The results are compared with those for the oxygenolysis of AlBr₃and SiCI₄. It was found that the reactivity of metal halides with O₂ is closely related to the ease of dissociation of the first halogen atom.     

基于自然对流PCR与毛细管电泳技术的牙周病原菌检测

细菌种类的快速识别在牙病防治中具有重要的应用价值。以牙周病原菌为研究对象,建立了DNA快速扩增的自然对流聚合酶链式反应(PCR)方法及毛细管电泳荧光光学检测系统。研究表明,当毛细管有效长度为8cm、电场强度为100V/cm时,50bp DNA ladder在筛分介质为0.5%HEC(羟乙基纤维素)(1 300K)中的分离效果最佳。毛细管电泳结果表明,采用自然对流法可以在25min内在圆柱腔体中实现牙周病原菌的快速PCR。     

Characteristics and Problem of Chrome-containing Refractory

One of characteristics of Cr2O3-containing refractory is excellent corrosion resistance. However, there is a problem of hexavalent chromium, which is noxious to the human body, and easily formed by the reactions among the refractory and CaO, Na2O and/or K2O in slag. In this article, the reason why the Cr2O3-containing refractory has excellent corrosion resistance, the forming conditions of hexavalent compounds, and the methods for suppressing generation of the compound, are described as a base of further development of excellent refractories.     

层片状双相TiAl合金拉伸与压缩变形行为差异

本文研究了层片状双相TiAl合金的室温拉伸压缩变形行为与断裂行为,发现在拉压变形条件下,其室温塑性有显著差异.并且这种差异与裂纹扩展路径有关.在室温拉伸与压缩变形时,该合金的拉压屈服应力随外载与层片界面间的夹角φ的变化趋势一致,而拉压断裂应变εf随夹角φ的变化趋势正好相反.外载与层片界面垂直时(φ=90°),拉伸断裂应变最小(εf≈0);压缩断裂应变最大(εf≈38%).夹角φ减小时,拉伸断裂应变增加,压缩断裂应变减小.在拉、压变形时裂纹的扩展路径不同.     

X-Ray Photoelectron Spectroscopy Analysis of Antiwear Tribofilms Produced on Boundary-Lubricated Steel Surfaces from Sulfur- and Phosphorus-Containing Additives and Metal Deactivator Additive

X-ray photoelectron spectroscopy (XPS) was performed on AISI 52100 steel surfaces subjected to sliding in the boundary lubrication regime at 32 and 100°C. The specimens were lubricated with base oil blended with individual additives containing sulfur (S), phosphorus (P), or metal deactivator, as well as base oil with all the previous additives in the same amounts as in the single blends. XPS spectra were analyzed to confirm the formation and determine the chemical composition of the antiwear tribofilms produced on the steel surfaces during sliding. The use of S- and P-containing additives on the tested disk surfaces revealed that tribochemical reactions resulted in the formation of antiwear tribofilms containing S- and P-rich components. Results for the multi-additive blend provided evidence for two components in the produced tribofilm, appearing to consist primarily of sulfide and phosphate. This investigation provides new insight into the competing roles of these compounds on the tribological properties of the antiwear tribofilms. The significance of the sulfide components is demonstrated by the more pronounced antiwear effect of the S-containing additive in the multi-additive formulation.     

Electrical and mechanical properties of ZrO2(2Y)/TiN composites and laminates made from these materials

High density composites with the compositions of ZrO₂(2Y):TiN=40:60 and 70:30 mol% have been fabricated by hot isostatic pressing for 2 h at 1500°C and 196 MPa. The electrical resistivities (ρ) of the two composites are very different; showing metallic behaviour in the first case and insulating behaviour in the latter case. These properties are highly dependent on the sample texture. Laminated materials with compositions of ZrO₂(2Y)/TiN=(40:60)/(70:30)/(40:60) mol% have been prepared by hot isostatic pressing. The electrical resistivities in the perpendicular and parallel to the interface directions have been determined to be ρ⊥≈1×109 and ρ∥≈ 1×10^-6 Ωm, respectively. A residual stress of as much as ≈ 150 MPa is induced in the interfaces. The fracture toughness is greatly affected by the residual stress. This revised version was published online in November 2006 with corrections to the Cover Date.