利用APT对RPV模拟钢中富Cu原子团簇析出的研究

提高了Cu含量的核反应堆压力容器（RPV）模拟钢经过880℃水淬和660℃调质处理,在370℃时效不同时间后,利用原子探针层析技术（APT）进行分析.结果表明:样品经过1150 h时效后,富Cu团簇正处于析出过程的形核阶段;经过3000和13200 h时效后析出了富Cu团簇,团簇的平均等效直径分别为1.5和2.4 nm,团簇中Cu的平均浓度分别为45%和55%（原子分数）,团簇的数量密度约为4.2×10²²m^-3;样品经过13200 h时效后,α-Re基体中的Cu含量为（0.15±0.02）%,仍然高于Cu在α-Fe中平衡固溶度的理论计算值,说明这时富Cu团簇的析出过程还没有达到平衡.对渗碳体的分析结果表明,Ni,Si和P偏聚在渗碳体和α-Fe基体的相界面附近,Mn,Mo和S富集在渗碳体中;并没有观察到Cu在相界面上偏聚的现象.     

煤液化装置用2.25Cr-1Mo-0.25V材料试验研究

近年来新发展的大型石油化工压力容器用钢2.25Cr-1Mo-0.25V有着取代传统用钢2.25Cr-1Mo的趋势。用4支25 kg真空感应炉小钢锭和83 t双真空锭水口料,进行了系统全面的试验室试验研究,对正式产品的生产试制提供了重要的参考和技术支撑。     

改进教学措施，提高高分子物理双语教学质量

双语教学是高等学校本科教学的大势所趋,如何才能将双语教学工作做好,落在实处是每位高校教师都应该思考的问题。我们通过对高分子物理双语教学工作的总结,结合教学反馈,对教学措施进行了补充和完善。     

核电专用涂层应用分析

介绍了核电站专用涂层性能要求和性能试验的相关标准。分析了核电站专用涂层的技术现状和应用状况。概括了美国核电专用涂料、秦山一期核电专用涂料和大亚湾核电专用涂料主要类型。提出国内核电专用涂层的发展要求。     

The treatment of sulfate-rich wastewater using an anaerobic sequencing batch biofilm pilot-scale reactor

This paper presents the results from 92 cycles of an anaerobic sequencing batch biofilm reactor containing biomass immobilized on inert support (mineral coal) applied for the treatment of an industrial wastewater containing high sulfate concentration. The pilot-scale reactor, with a total volume of 1.2 m³, was operated at sulfate loading rates ranging from 0.15 to 1.90 kgSO₄²⁻/cycle (48 h — cycle) corresponding to sulfate concentrations of 0.25 to 3.0 gSO₄²⁻ l^− 1. Domestic sewage and ethanol were utilized as electron donors for sulfate reduction. Influent sulfate concentrations were increased in order to evaluate the minimum COD/sulfate ratio at which high reactor performance could be maintained. The mean sulfate removal efficiency remained between the range of 88 to 92% at several sulfate concentrations. Temporal profiles along the 48 h cycles were carried out under stable operation at sulfate concentrations of 1.0, 2.0 and 3.0 gSO₄²⁻ l^− 1. Sulfate removal reached 99% for cycle times of 15, 25, and 30 h, and the effluents sulfate concentrations were lower than 8 mgSO₄²⁻ l^− 1. The results demonstrate the potential applicability of the anaerobic configuration for the biological treatment of sulfate-rich wastewaters.     

Theoretical analysis of inhibition effect on steady states of enzymatic membrane reactor with substrate and product retention for reaction producing weak acid

The aim of this study is to formulate a model of enzymatic membrane reactor (EMR), i.e., a continuous, stirred tank bioreactor with full enzyme recycle, for a reaction producing a weak acid, and to explore the effect of substrate and product inhibition of different mechanisms coupled with transport properties of the membrane on the static behaviour of the system. The inhibition of an enzyme by a substrate leads to the non-monotonicity of reaction rate expression with respect to the substrate concentration. If a product of enzymatic reaction, taking place in the EMR, influences the pH of a reaction mixture this is also the factor causing the non-monotonicity of the substrate and product dependent reaction rate. The character of these dependencies affects substantially the structure of the steady states of the reactor. The bifurcation diagrams, shown in the work, are of different characters depending on the bifurcation parameter. It has been found, that bifurcation diagrams for competitive and uncompetitive inhibition by a substrate differ in the number and position of bifurcation points. Steady states of multiplicity five have been localised in case of uncompetitive inhibition by the substrate at high affinity of the enzyme to this substrate. Retention of reagents, related to transport properties of a membrane, influences significantly the effectiveness of a process. A specially written software in Delphi™ has been used for the calculations.     

Electrochemical membrane reactor: Synthesis of quaternary ammonium hydroxide from its halide by in situ ion substitution

Electrochemical membrane reactors (EMRs) with two compartments (EMR-2: anion-exchange membrane (AEM) separated catholyte and anolyte) and three compartments (EMR-3: three compartments separated by two AEMs to avoid contact between the product and the electrodes) were developed for the synthesis of tetrabutylammonium hydroxide (TBAOH) from tetrabutylammonium bromide (TBABr) by in situ ion substitution. In house prepared AEM with good physicochemical, electrochemical properties and excellent stabilities was used. Schematic diagrams are presented for the possible synthesis of TBAOH from TBABr by in situ ion substitution in EMR-2 and EMR-3. Synthesis of TBAOH using EMR-2 and EMR-3 was achieved under different experimental conditions and process parameters (rate of synthesis, current efficiency (CE) and energy consumption) were estimated. In EMR-2, relatively slow synthesis of TBAOH with low recovery was explained due to Hofmann elimination of TBAOH in contact with the electrode. While in EMR-3, relatively faster rate of TBAOH synthesis with its high recovery and current efficiency indicated practical application of the developed process for the efficient synthesis of TBAOH without the use of any additives or reagents.     

Design and testing of continuous acid-catalyzed esterification reactor for high free fatty acid mixed crude palm oil

Using acid-catalyzed esterification, a continuous reactor, containing four separate continuous stirred tank reactors (CSTR's), was designed and used to reduce the free fatty acid (FFA) content of mixed crude palm oil (MCPO). A six-blade disk turbine and four baffles were installed in each of the four reactors to enhance mixing. The complete reactor was tested using response surface methodology (RSM). A 5-level, 4-factor, central composite design (CCD) was employed to optimize the four important reaction variables (methanol/oil ratio; sulfuric acid/oil ratio; speed of the stirrer; and residence time) to reduce the FFA content of the MCPO to less than 1 wt.% of oil. Multiple regression analysis was used to derive a polynomial equation to predict the FFA content of the product. This was then used to indicate optimal conditions for reducing the FFA in mixed crude palm oil to less than 1 wt.%.     

Synthesis, characterization and performance of CuO/La2O3 composite catalyst for ammonia catalytic oxidation

This work considers the oxidation of ammonia (NH₃) by selective catalytic oxidation (SCO) over a CuO/La₂O₃ composite catalyst at temperatures between 150 and 400 °C. A CuO/La₂O₃ composite catalyst was prepared by co-precipitation of copper nitrate and lanthanum nitrate at various molar concentrations. This study also considers how the concentration of influent NH₃ (C₀ = 1000 ppm), the space velocity (GHSV = 92,000 l/h), the relative humidity (RH = 12%) and the concentration of oxygen (O₂ = 4%) affect the operational stability and the capacity for removing NH₃. The catalysts that were characterized using FTIR, XRD, UV-Vis, BET and PSA, have shown that the catalytic behavior is related to the copper (II) oxide, while lanthanum (III) oxide may serve only to provide active sites for the reaction during a catalyzed oxidation run. The experimental results show that the extent of conversion of ammonia by SCO in the presence of the CuO/La₂O₃ composite catalyst was a function of the molar ratio. The ammonia was removed by oxidation in the absence of CuO/La₂O₃ composite catalyst, and around 93.0% NH₃ reduction was achieved during catalytic oxidation over the CuO/La₂O₃ (8:2, molar/molar) catalyst at 400 °C with an oxygen content of 4.0%. Moreover, the effect of the reaction temperature on the removal of NH₃ in the gaseous phase was also monitored at a gas hourly space velocity of under 92,000 h^− 1.