后发酵过程中乙醇对豆豉抗氧化能力的影响

以黄豆为原材料,接种米曲霉制作豆豉,在豆豉后发酵过程中设定了不同乙醇添加量,测定了不同乙醇添加量的豆豉样品清除DPPH(2,2-diphenyl-1-picrylhydrazyl hydrate)及ABTS[2,2-’azinobis-(3-ethylbenzthia-zoline-6-sulfonic acid)]自由基能力、Fe2+螯合能力、还原能力,评价了乙醇对豆豉抗氧化能力的影响。后发酵过程中,豆豉的抗氧化能力持续增大,醇对豆豉的抗氧化能力有影响,发酵相同时间的豆豉,抗氧化能力随乙醇含量的增大而下降。     

碱源对MCM-22分子筛合成的影响

研究了氧化铝在碱性环境中的溶解热力学,在n(SiO2)/n(Al2O3)=60、n(H2O)/n(SiO2)=24.5、n(HMI)/n(SiO2)=0.1的条件下,分别以NaOH、KOH和Ba(OH)2为碱源合成分子筛。以NaOH为碱源、当n(Na+)/n(Al2O3)的比值小于0.049时,合成产物为无定型物;当该比值大于等于0.049、小于等于0.123时,合成产物为MCM-22分子筛;而当该比值等于0.245时,合成产物转化为ZSM-35分子筛。以KOH为碱源时,在研究的范围内,即n(K+)/n(SiO2)的比值在0.0031～0.0873范围内时,合成产物均为无定型物。以Ba(OH)2为碱源,当n(Ba2+)/n(SiO2)的比值小于等于0.0031时,合成产物为无定型物;当该比值大于等于0.0062、小于等于0.0488时,合成产物均为Ba-ZSM-35分子筛,且结晶度随该比值的升高而逐渐降低。在一定条件下,Na+的存在对MCM-22分子筛的合成是必不可少的。     

Oil prices and the impact of the financial crisis of 2007–2009

Oil prices increased dramatically during 2004–2006. Industry experts initially attributed these price increases to fundamental factors such as the rise in global demand, but also because of disruptions in the supply of oil. The price increases however were so substantial that additional factors are needed to explain such dramatic changes. We propose that the decline in the value of the U.S. dollar measured both by the appreciation of the Euro and of gold prices, played an important role as oil suppliers demanded compensation for the declining value of the dollar. Using a Markov switching regime methodology we find evidence that this hypothesis is true prior to the financial crisis, but its validity does not hold after the crisis when oil prices crashed and the dollar rallied.     

络合浸渍氧化镁改性MCM-22催化甲苯烷基化反应的研究

以硝酸镁为前驱体,乙酰乙酸乙酯为络合剂,通过络合浸渍的方法制备不同负载量的MgO/MCM-22催化剂。在气相连续流动固定床反应器上,对甲苯与碳酸二甲酯(DMC)烷基化合成对二甲苯的过程进行了研究。采用X射线衍射、N2吸附-脱附、NH3程序升温脱附和吡啶吸附红外光谱等手段对催化剂进行了表征。结果表明,采用乙酰乙酸乙酯为络合剂,可以有效的覆盖分子筛外表面的酸性,避免其孔内酸性受到影响,催化剂能在保持较高甲苯转化率的同时显著提高对二甲苯选择性。在反应温度380℃、n(甲苯)∶n(DMC)=4∶1、空速1h-1条件下,当MgO负载量达到15%时,对二甲苯选择性和甲苯转化率分别为54.0%和34.3%。     

Visual study of flow patterns during condensation inside a microfin tube with different tube inclinations

In this paper, flow patterns and their transitions for refrigerant R-134a condensing in a microfin tube are visually observed and analyzed. The microfin tube has been provided with different tube inclination angles of the direction of fluid flow from horizontal, α. The experiments were performed for seven different tube inclinations, α, in a range of − 90° to + 90° and refrigerant mass velocities in a range of 53 to 212 kg/m²s for each tube inclination angle during condensation of R-134a vapor. From analysis of acquired data, it was found that the tube inclination strongly influenced the vapor and condensate liquid distribution. Annular flow was the dominant flow pattern for vertical downward flow, α = − 90°. Annular flow, semi annular flow and stratified flow were observed for α = − 60°and − 30°. Annular flow, wavy-annular flow and stratified-wavy flow exist in sequence for horizontal tube. Annular flow and wavy-annular flow were observed for α = + 30°and + 60°. Annular flow, annular-wavy flow, churn flow and slug flow occurred for α = + 90°.     

Relative energy price and investment by European firms

A dynamic model of investment is estimated with data on non-financial firms in 15 European countries across 25 industries over 1991–2006. A rise in real energy price reduces the degree of persistence in the investment adjustment cost function. Panel results suggest that in manufacturing a 1% rise in real energy price reduces investment by a country's firms by 1.9% relative to that by firms in other countries with a smaller effect for non-manufacturing firms. The negative effect of a higher relative price of energy on firm-level investment is significantly less marked the larger the firm. Results imply that stabilizing the relative price of energy would steady firm investment with greater gains in stability at smaller and medium sized firms. Results are robust to consideration of country business cycle effect and firm leverage. Estimation of investment is based on the Euler equation approach with over 21,000 observations. Individual country regressions imply that a rise in the relative price of energy price has a statistically significant negative effect on firm-level investment in 14 out of 15 countries. To avoid dynamic panel bias estimation is by generalized method of moments with instrumental variables.     

改性MCM-22分子筛催化长链烯烃对苯烷基化反应的研究

采用水热静态晶化法合成了MCM-22分子筛,考察不同原料配比对合成的影响,并用X射线衍射、N_2等温吸附和NH_3-TPD等方法对其进行了表征,并对MCM-22分子筛进行改性,考察其改性前后对苯和长链烯烃烷基化反应的催化活性。改性后催化剂Ni-JC-4(A)-0.001和JC-4(B1)对烯烃的转化率分别为94.84%和92.97%;对烷基苯的选择性分别为98.85%和99.02%,使用寿命分别达到27 h和37 h以上。实验表明,用1 mmol/L NiSO_4交换改性的催化剂和加入大孔Al_2O_3改性后的催化剂均具有较高的催化活性,使用寿命得到提高。     

氧化物改性MCM-22上甲苯与甲醇的烷基化性能研究

 用动态水热法合成了MCM-22分子筛，以混合稀土、乙酸镁、硅酯等为改性剂，采用浸渍法对其进行了改性。采用NH3-TPD、IR等表征了改性前后催化剂的酸性，考察了改性MCM-22分子筛上甲苯与甲醇烷基化合成对二甲苯的反应性能。结果表明，H型MCM-22分子筛在该反应中具有很高的催化活性，但是对二甲苯和二甲苯的选择性都比较低。经过混合稀土、醋酸镁改性之后，对二甲苯的选择性达到62.61%，催化剂综合性能明显提高。     

微孔分子筛ZSM-22的合成及其应用研究进展

ZSM-22分子筛具有中等强度的表面酸性和适宜的孔径结构,在长链烷烃异构化和烯烃异构化等反应中表现出优异的催化活性。ZSM-22分子筛的催化活性、选择性、热稳定性及使用寿命在很大程度上取决于其孔结构、表面酸性强度、晶粒尺寸和晶体化学组成等物化性质,掌握物化性质对催化性能的影响规律对催化剂设计至关重要。通过对比ZSM-22分子筛不同合成方法的特点,分析不同合成方法对分子筛的活性、选择性、结构等物化性质的影响,总结了ZSM-22分子筛的应用现状、经改性后应用效果的优化及范围延伸。     

F91钢管与A691Gr.1-1/4CrCL22钢管焊接接头的热处理

为了解决江苏华电句容二期（2×1 000 MW）扩建工程4#机组低压旁路蒸汽管道低旁阀F91钢管与阀后A691Gr.1-1/4CrCL22钢管异种钢接头直接焊接无法进行热处理的问题,通过分析F91钢与12Cr1MoVG 钢、12Cr1MoVG钢与A691Gr.1-1/4CrCL22钢两组异种钢焊接接头的焊接热处理性能,采用在F91钢与A691Gr.1-1/4CrCL22钢异种钢焊接接头中间增加12Cr1MoVG过渡段的方法进行处理。对焊接及热处理完成后的两组异种钢接头进行无损检测和硬度检验,结果均符合相关标准要求。证明了采用增加12Cr1MoVG过渡段处理F91与A691Gr.1-1/4CrCL22异种钢焊接接头的热处理问题的可行性。