栲胶脱硫工艺中含硫副产物生成的热力学分析

采用热力学方法研究了栲胶脱硫工艺中HS-与钒的反应机理和副反应的吉布斯自由能变。研究结果表明,脱硫液中五价钒主要是以HV2O3-7形式存在,四价钒主要是以V4O2-9形式存在。HS-与五价钒反应可瞬间生成多硫离子S2-x,然后S2-x转化为单质硫。在栲胶脱硫工艺的操作温度下,HS-和S2-x与氧气作用均可生成副产物,但S2-x比HS-活泼,更易发生副反应,且S2-x中x的值越小越活泼。在S2-x转化为副产物S2O2-3的过程中,温度越高,越有利于副反应的发生。对栲胶脱硫工艺而言,S2-x是生成副产物的活性中间产物,因此,栲胶脱硫液在进入再生系统前,应使S2-x尽可能多地转化为S8结构。     

HYSYS在常减压装置中的应用

文章利用HYSYS软件建立较准确的常减压装置全流量模型,利用常压塔模型优化,将重整料干点从155℃提高至166℃,核算每天可增效3.55万元;减压塔模型通过比较重柴油与轻蜡油两者内混与外混方式外送的经济效益,核算出外混节能效果更好,从而定量指导了实际生产。     

环境微生物学实验教学改革初探

笔者结合多年的实验课程教学经验,对传统的环境工程微生物学实验教学模式进行改革.通过选择精品教材、合理运用导语和课堂小结、融入逼真的图片和动画优化教学内容,紧密联系实际,取得了令人满意的教学效果.     

加强实验室规范化管理,提高实验室资源共享

高校实验室是进行实验教学、科学研究和社会服务的重要场所,文章分析了高校实验室建设与管理的现状,提出加强实验室制度建设、加大实验室开放力度,实现资源共享,提高大型设备利用率,是实验室管理规范化和科学化的重要途径。     

2015年中国经济形势及政策走向判断

指出了我国仍具备保持稳定增长的基本条件,但经济运行仍面临较多困难和挑战。2015年我国经济将呈现稳中缓降态势。针对经济运行中存在的困难和挑战,应坚持稳中求进、适应新常态,推动新发展。     

Delignification of intact biomass and cellulosic coproduct of acid‐catalyzed hydrolysis

The kinetics of acid‐catalyzed hemicellulose removal and also alkaline delignification of oat hull biomass were investigated. All three operational parameters namely, catalyst concentration (0.10–0.55 N H₂SO₄), temperature (110–130°C), and residence time (up to 150 min) affected the efficiency of hemicellulose removal, with 100% of hemicellulose removed by appropriate selection of process parameters. Analysis of delignification kinetics (in the temperature range of 30–100°C) indicated that it can be expressed very well by a two‐phase model for the crude biomass and also for the hemicellulose‐prehydrolyzed material. The application of acid‐catalyzed prehydrolysis improved the capacity of lignin dissolution especially at lower temperatures (30 and 65°C) and accelerated the dissolution of lignin. This acceleration of delignification by prehydrolysis was possible at all levels of temperature in the bulk phase; however, results were more significant at the lower temperatures in the terminal phase. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1783–1791, 2015     

Structure–property relationship of polyimide fibers containing ether groups

The copolyimide (co‐PI) fibers with outstanding mechanical properties were prepared by a two‐step wet‐spinning method, derived from the design of combining 4,4′‐oxydianiline (ODA) with the rigid 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA)/p‐phenylenediamine (p‐PDA) backbone. The mechanical properties of PI fibers were drastically improved with the optimum tensile strength of 2.53 GPa at a p‐PDA/ODA molar ratio of 5/5, which was approximately 3.7 times the tensile strength of BPDA/p‐PDA PI fibers. Two‐dimensional wide‐angle X‐ray diffraction indicated that the highly oriented structures were formed in the fibers. Two‐dimensional small‐angle X‐ray scattering revealed the existence of the needle‐shaped microvoids aligned parallel to the fiber axis, and the introduction of ODA led to the reduction in the size of the microvoids. As a result, the significantly improved mechanical properties of PI fibers were mainly attributed to the gradually formed homogeneous structures. The co‐PI fibers also exhibited excellent thermal stabilities of up to 563°C in nitrogen and 536°C in air for a 5% weight loss and glass transition temperatures above 279°C. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42474.     

Recovery and characterization of lignin from alkaline straw pulping black liquor: As feedstock for bio‐oil research

Conversion of lignin derived from lignocellulosic biomass to bio‐oil has the promising potential to significantly reduce petroleum dependence. For that purpose, it is necessary to search for a low‐cost lignin source. In this study, lignin sample was separated from straw pulping black liquor by HCl‐precipitation, followed by extraction with a mixture of dioxane and water. The content of lignin in the total black liquor solid reached up to 34.8%, determined by UV spectroscopy, and the yield could account for 74.4% of the total lignin composition. The structure of lignin was investigated by various spectroscopic techniques such as FTIR, ¹H‐NMR, XRD, and XPS. The structural analysis revealed that recovered lignin preserved basic lignin structure, but had relatively lower amount of β‐O‐4 linkages. The molecular weights were studied through THF‐eluted GPC showing that separated lignin had the low M_n, which was favorable for the full degradation process during conversion of lignin to bio‐oil. Therefore, a feasible solution for effective utilization of lignin in straw pulping black liquor as feedstock for bio‐oil was proposed in the study. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42057.     

专业课授课方法和考核方式的改革探索与实践

本文对大学四年级专业课程教学过程中存在的问题进行了分析,提出了一系列教学改革的方法:优化整合课程内容,改革课堂教学方法和考核方式,激发学生学习兴趣,减轻学生课业负担,提升教学质量。课程内容划分为讲授内容和讨论内容。教学方法引入了"讨论式"教学,并改革了考核方式。