NiMn2O4 spinel as an alternative coating material for metallic interconnects of intermediate temperature solid oxide fuel cells

In an effort to improve the performance of SUS 430 alloy as a metallic interconnect material, a low cost and Cr-free spinel coating of NiMn₂O₄ is prepared on SUS 430 alloy substrate by the sol-gel method and evaluated in terms of the microstructure, oxidation resistance and electrical conductivity. A oxide scale of 3-4 μm thick is formed during cyclic oxidation at 750 °C in air for 1000 h, consisting of an inner layer of doped Cr₂O₃ and an outer layer of doped NiMn₂O₄ and Mn₂O₃; and the growth of Cr₂O₃ and formation of MnCr₂O₄ are depressed. The oxidation kinetics obeys the parabolic law with a rate constant as low as 4.59 × 10⁻¹⁵ g² cm⁻⁴ s⁻¹. The area specific resistance at temperatures between 600 and 800 °C is in the range of 6 and 17 mΩ cm². The above results indicate that NiMn₂O₄ is a promising coating material for metallic interconnects of the intermediate temperature solid oxide fuel cells.     

低铬白口铸铁的组织与磨粒磨损性能

采用硅进行低铬白口铸铁的合金化，试验发现，随着硅含量增加，碳化物形貌由网状向断网状、分散孤立的条状转变；碳化物的含量增加，尺寸细化；碳化物硬度及材料的整体硬度也逐渐增加。在铬含量为59／5左右、硅含量〉2．5％时，碳化物出现了M7C3型，耐磨性也随着增加，该材料的抗冲击磨粒磨损性能最好的是下贝氏体组织。淬火温度和冷却方式对该类白口铸铁的抗冲击磨粒磨损性能影响不大。     

Single-layer white polymer light-emitting diodes based on an iridium (III) complex containing alkyltrifluorene picolinic acid

To explore the relationship between the electronic properties of a host/dopant system and obtain a high-efficiency single-dopant white polymer light-emitting device two novel blue-emitting cyclometalated iridium (III) complexes of (dfppy)₂Ir(Tfl-pic) and (dfppy)₂Ir(Brfl-pic) have been synthesized and characterized, where dfppy is 2-(2,4-difluorophenyl)pyridine, Tfl-pic and Brfl-pic are picolinic acid derivatives containing trialkylfluorene and dibromoalkylfluorene units bridged with an alkoxy chain, respectively. Both iridium (III) complexes exhibited blue emission in dichloromethane solution and their neat films, and possessed good dispersibility and thermal properties. Two different devices using (dfppy)₂Ir(Tfl-pic) as a single component emitter and a blend of poly(N-vinylcarbazole) and 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole as the host matrix were fabricated. Improved white emission was obtained by adjusting the electron injection layer leading to efficient exciplex emission.     

用于测量高强度脉冲中子及γ射线剂量的真空室

本文报告了用于测量高强度脉冲中子及γ射线剂量的真空室探测器和直读真空室剂量计的研制。两种真空室在γ、Ｘ射线、１４ＭｅＶ中子、稳态和脉冲核反应堆中子、γ射线混合场上实验表明，其主要剂量学性能基本上达到设计要求。真空室剂量计在１０￣４Ｇｙ／ｓ下无剂量率依赖性，含氢材料壁真空室的快中子、γ射线灵敏度比近１：１，铝壁真空室受１０￣６Ｇｙ（￣（６０）ＣＯ）照射，其性能几乎没有变化。     

微机控制下的沙盘灯光系统的研制

介绍一种微机控制下的沙盘灯光系统，可产生各种变化的灯光，用以与沙盘配合，产生各种所需的视觉效果。     

The effect of Mn on the oxidation behavior and electrical conductivity of Fe-17Cr alloys in solid oxide fuel cell cathode atmosphere

Four Fe-17Cr alloys with various Mn contents between 0.0 and 3.0 wt.% are prepared for investigation of the effect of Mn content on the oxidation behavior and electrical conductivity of the Fe-Cr alloys for the application of metallic interconnects in solid oxide fuel cells (SOFCs). During the initial oxidation stage (within 1 min) at 750 °C in air, Cr is preferentially oxidized to form a layer of Cr₂O₃ type oxide in all the alloys, regardless the Mn content, with similar oxidation rate and oxide morphology. The subsequent oxidation of the Mn containing alloys is accelerated caused by the fast outward diffusion of Mn ions across the Cr₂O₃ type oxide layer to form Mn-rich (Mn, Cr)₃O₄ and Mn₂O₃ oxides on the top. After 700 h oxidation a multi-layered oxide scale is observed in the Mn containing alloys, which corresponds to a multi-stage oxidation kinetics in the alloys containing 0.5 and 1.0 wt.% of Mn. The oxidation rate and ASR of the oxide scale increase with the Mn content in the alloy changes from 0.0 to 3.0 wt.%. For the application of metallic interconnects in SOFCs, Mn-free Fe-17Cr alloy with conducting Cr free spinel coatings is preferred.     

Effects of initial pressure and hydrogen concentration on laminar combustion characteristics of diluted natural gas–hydrogen–air mixture

In this study, the experiment study about the laminar burning velocity and the flame stability of CO₂ diluted natural gas–hydrogen–air mixture was conducted in a constant volume combustion vessel by using the high-speed schlieren photography system. The unstretched laminar burning velocity and the Markstein length at different hydrogen fractions, dilution ratios and equivalence ratios and with different initial pressures were obtained. The flame stability was studied by analyzing the Markstein length, the flame thickness, the density ratio and the flame propagation schlieren photos. The results showed that the unstretched laminar burning velocity would be reduced with the increase of the initial pressure and dilution ratio and would be increased with the increase of the hydrogen fraction of the mixture. Meanwhile, the Markstein length would be increased with the increase of the equivalence ratio and the dilution ratio. Slight flaws occurred at the early stage. At a specific equivalence ratio, a higher initial pressure and hydrogen fraction would cause incomplete combustion.     

高锰酸盐用于H2O2漂白预处理的初步研究

本文分析了四种预处理方法对化学浆过氧化氢漂白的影响，其中采用正交试验对酸性高锰酸钾用于化学浆过氧化氢漂白预处理过程进行了研究。探索了预处理段对漂白效果、成纸物理强度和机械强度的影响。     

Photocatalytic activities of Sr2Ta2O7 nanosheets synthesized by a hydrothermal method

Sr₂Ta₂O₇ nanosheets have been synthesized by a hydrothermal method without using any template. The thickness, widths, and lengths of Sr₂Ta₂O₇ nanosheets are about 10–50 nm, 50–150 nm, and 500 nm, respectively. The optimum conditions for the formation of the nanosheets are maintaining the reactants at 260 °C for 7 days. On basis of the experimental data, a possible formation mechanism of the nanosheets under the hydrothermal conditions was proposed. The photocatalytic activity for water splitting was investigated under ultraviolet irradiation. It has been found that Sr₂Ta₂O₇ nanosheets, compared to the bulk Sr₂Ta₂O₇ sample, showed a higher photocatalytic activity even in the absence of a cocatalyst. The higher activity of the hydrothermally synthesized sample is attributed to its larger surface areas and nanoscale structure.     

微波等离子体炬摄谱特性的初步研究

微波等离子体是新研制的一种原子发射光谱分析激发源,其特点是结构简单、造价低、激发效率高,是一种有实际开发价值的分析光源。我们用摄谱法对其性能作了初步研究,主要是酸性、气流量、输入功率的影响,其目的在于探索把它应用于摄谱分析的可能性。