PEDT膜修饰电极的制备及对苯二酚电催化作用的研究

电催化氧化技术应用的关键问题之一在于寻找和研制开发催化活性高、导电性能好的阳极材料。采用电化学聚合法在硫酸钾溶液中制备了聚3,4-乙撑二氧噻吩膜修饰电极（PEDT）并通过自制的PEDT膜修饰电极首次对对苯二酚和邻苯二酚的电催化作用进行了探讨。     

液-固发酵法沙棘果醋的风味研究

以沙棘果汁为原料,采用液-固发酵法研制沙棘果醋。用顶空固相微萃取(HS-SPME)和气质联用(GC-MS)分析技术,考察了沙棘果醋的风味成分,并与国内恒顺优质香醋的风味对照,确定共有成分30种:酯类10种、酸类9种、醇类4种、酮类2种、醛类2种、吡嗪类2种、呋喃类1种。酚类、四氢化吡咯、3-甲基-4-乙酰基吡唑等风味化合物赋予了沙棘果醋独特的风味。     

Aerobic oxidation of alcohols over Au/TiO2: An insight on the promotion effect of water on the catalytic activity of Au/TiO2

The unique and significant promotion effect of water has been evidenced by the selective oxidation of benzyl alcohol to benzaldehyde over Au/TiO₂ catalysts. Water has dual promotional functions in the reaction system: to help form unique microdroplets in a multiphase reaction system and to assist the oxygen adsorption and activation. The conversion of benzyl alcohol at a molar ratio of water to solvent (p-xylene) of 7 is 7 times higher than in the absence of water. The present work has highlighted the potential of Au/TiO₂ catalysts in aerobic oxidation of alcohols in the unique multiphase reaction system with water as promoting solvent.     

金属离子对脂肪族聚酯降解性能的影响

在土壤培养液中添加不同种类的金属离子,研究了它们对可生物降解聚酯聚乳酸（PLA）、聚丁二酸丁二酯（PBS）膜降解性能的影响。采用傅里叶变换红外光谱仪表征了PLA和PBS膜降解前后的化学结构。结果表明：所有降解后的膜表面均有明显被侵蚀的痕迹;在土壤培养液中的Mg^2＋,Zn^2＋,Ca^2＋对PLA的降解性能有促进作用,对PBS的降解性能则影响不大;降解后PLA膜的玻璃化转变温度有所升高,但PBS膜变化不大。     

一个新的颗粒填充聚合物复合材料导热模型

基于最小热阻力法则和比等效导热系数法则,建立一新的颗粒填充聚合物复合材料的导热模型并导出等效导热系数公式。应用该公式估算了酚醛树脂／铝粉和酚醛树脂／石墨复合材料的等效导热系数,并与试验测量数据比较。结果表明,导热系数的理论预测值和试验数据相当接近。     

Orientation of the Monomeric Porin OmpG in Planar Lipid Bilayers

Outer membrane protein G (OmpG) is a non‐selective porin from Escherichia coli. OmpG is a monomer, which makes it unusual among porins, and suggests that it may be useful in biotechnology. In planar lipid bilayers, individual OmpG pores reconstituted by insertion from detergent exhibit pronounced asymmetry in current‐voltage relationships and voltage‐dependent gating. Here, this asymmetry is used to deduce the orientation of OmpG in the bilayers. We introduced two cysteines into the extracellular loops of OmpG. Cleavage of the disulfide bond formed by these residues significantly increases spontaneous gating of the pore. By adding DTT to one side of the bilayer or the other, we demonstrated that pores showing a quiet trace at negative potentials have a “trans” conformation (extracellular loops on the trans side of the bilayer), while pores showing a quiet trace at positive potentials have a “cis” conformation (extracellular loops on the cis side). With this knowledge, we examined the binding of a cyclodextrin to OmpG. When the cyclodextrin was presented to the extracellular face of the pore, transient multisite interactions were observed. In contrast, when the cyclodextrin was presented to the periplasmic face, a more stable single‐site interaction occurred. Because the cyclodextrin can act as a molecular adapter by binding analytes, this information serves to advance the use of OmpG as a biosensor.     

聚合物共混体系中分散相在物理老化过程的尺寸变化

文章研究了退火过程对乙烯-辛烯共聚物/热塑性聚氨酯不相容共混物的相聚集现象的影响,利用扫描电子显微镜分析分散相的粒径,结果表明,随着退火温度的提高和时间的延长,分散相的粒径变大、分布变宽,聚集长大机理起关键作用。     

预吸附水对低阶煤成浆性能的影响

针对低阶煤由于内水分高、含氧量高导致的成浆性差的问题,研究了预吸附水对低阶煤成浆性能的影响.结果表明,预吸附水处理后低阶煤的成浆性能得到了较大的提高,当制浆浓度达到63%时黏度仅为1 200 mPa·s,比相同黏度下原煤制浆浓度提高了约3%.元素分析结果表明,预吸附水后低阶煤含氧官能团含量没有发生变化;比表面积和孔隙结构测试结果表明,煤样预吸附水处理后比表面积减少,吸附水阻塞了一部分中孔,使总孔容积减少,减少了煤孔隙中分散剂的吸附,同时预吸附水使煤样的润湿性能增强,煤粒间的静电斥力增加,从而提高了低阶煤的成浆性能.     

铸件充型过程流动的三维计算机模拟

采用SIMPLEC算法计算流场,一种基于VOF的改进方法用于三维自由表面处理,在微机上实现了一个优化的铸件充型过程流动模拟的CAE工具。采用面向对象方法开发数值模拟软件,提高软件的可靠性、可重用性、可扩展性和可维护性。并对熔融铝合金充填一矩形方腔的过程进行了模拟计算和实验验证,结果表明两者基本吻合。     

微合金元素镍和铌对金属粉芯焊丝焊接接头性能的影响

在自行研制的高强钢金属粉芯焊丝的基础上,通过拉伸试验、冲击试验等方法分别研究了微合金元素镍和铌对高强钢焊接接头力学性能的影响,并结合金相分析、扫描电镜分析、化学成分分析等方法从组织和成分的角度对两种微量合金元素的影响机理进行了合理的解释。结果表明,微合金元素镍具有增加焊缝组织中贝氏体和马氏体组织含量从而提高焊接接头强度的作用,并能促进针状铁素体形成而改善接头低温冲击韧性;微合金元素铌同样具有促进焊缝组织形成针状铁素体作用,同时通过细化晶粒和沉淀强化提高接头的抗拉强度。