离子液体辅助合成BiOBr微球和纳米片及其光催化性能

使用混合溶剂热法,以1-己基-3-甲基咪唑溴盐离子液体([Hmim]Br)和Bi(NO3)3·5H2O为反应物,乙二醇水溶液为溶剂,制备了BiOBr微球和纳米片。利用X射线衍射(XRD)、扫描电镜(SEM)、紫外可见漫反射(UV-Vis)以及N2吸附-脱附等手段对其进行了物相和结构的表征。在可见光照射下,以罗丹明B(RhB)为目标污染物,研究了离子液体存在下,溶剂组成对BiOBr光催化活性的影响。结果表明,当乙二醇与水的比例为3∶1~1∶1时所制备的BiOBr纳米片具有最高的光催化活性;同时,BiOBr纳米片光催化剂稳定性良好,循环使用8次后光催化活性基本稳定。     

聚合物光伏电池材料真空极化取向的研究

聚[2-甲氧基5-(2′-乙基己氧基)对苯乙炔](MEH-PPV)和聚3-己基噻吩(P3HT)是典型的共轭聚合物,可以作为新型的光伏电池材料。真空条件下对两种聚合物材料进行极化取向实验,可以增加载流子的迁移能力,提高导电能力,有利于聚合物太阳能薄膜电池性能的改善。     

原位法P3HT-COOH/CdS纳米复合材料的制备与表征

以二水乙酸镉(Cd(OOCCH3)2·2H2O)为镉源,硫粉(S)为硫源,二氯苯(DCB)和二甲基亚砜(DMSO)为混合溶剂,末端羧基化聚-3-己基噻吩(P3HT-COOH)为模板,原位法合成了P3HT-COOH/CdS纳米复合材料;并利用核磁共振氢谱、傅里叶变换红外光谱、X射线衍射、透射电子显微镜、紫外-可见光谱和荧光光谱等分析测试方法对其组成、形貌、光电性能等进行了表征。研究了不同反应温度及S/Cd摩尔比对复合材料形貌及光电性能的影响。实验结果表明,所合成的CdS纳米粒子均匀分布在P3HT-COOH/CdS复合材料中;CdS的尺寸和分布不仅受温度影响,还很大程度上受S/Cd摩尔比的影响;P3HT-COOH/CdS纳米复合材料有较强的荧光淬灭,表明CdS与P3HT-COOH之间有电荷转移。     

聚-3-羟基丁酸酯及其共聚物的合成与表征

合成一种环烷氧锡化合物,用氢谱、元素分析和质谱对其结构进行表征确认,并以其作为β-丁内酯开环聚合的引发剂制备聚-3-羟基丁酸酯,考察了单体引发剂配比、聚合时间和聚合温度等聚合条件对聚合产物特性粘度的影响.由丁内酯与丙交酯、己内酯共聚制备聚(丁内酯-丙交酯)和聚(丁内酯-己内酯)共聚物,并用FT-IR、1H-NMR、DSC等手段对聚合物的结构及性能进行了表征.     

TiO_2/P3HT纳米复合微粒制备及表征研究

以纳米二氧化钛(TiO_2)和聚3-己基噻吩(P3HT)为原料,氯仿为溶剂,制备了TiO_2/P3HT纳米复合微粒。采用透射电镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、紫外-可见光漫反射光谱(UV-Vis DRS)等方法对复合微粒的结构和性能进行表征和分析。结果表明,通过P3HT修饰后的TiO_2/P3HT与纯TiO_2相比,晶型、粒径和形貌基本没有发生改变,平均粒径22nm;纳米TiO_2/P3HT比纯TiO_2在可见光区的光吸收能力增强,当TiO_2∶P3HT摩尔配合比为30∶1时,在波长508nm,TiO_2/P3HT的吸光度达到1.0123,而纯TiO_2的吸光度为0.10824。     

2种苯并咪唑衍生交替共聚物的合成及性能

以苯并噻二唑作为初始原料,通过Sonogashira、Suzuki反应将4,7-二溴-2-己基-1,3-苯并咪唑单体分别与带有不同烷氧基链的对苯乙炔、9,9-二辛基芴进行交替共聚,得到了聚[2-己基-1,3-苯并咪唑-1,4-二乙炔基-2,5-二辛氧基苯](P1)、聚[2-己基-1,3-苯并咪唑-1,4-二乙炔基-2,5-二(十二烷氧基)苯](P2)和聚[2-己基-1,3-苯并咪唑-9,9-二辛基芴](P3)。采用红外光谱、核磁共振等手段对单体和共聚物的结构进行了表征,利用紫外-可见吸收光谱、荧光量子效率测试和循环伏安法对聚合物的光、电化学性能进行了探讨。结果表明,共聚物P1、P2均在445 nm处出现紫外-可见吸收峰,共聚物P3在376 nm处出现紫外-可见吸收峰。P2、P3共聚物的相对荧光量子效率分别为80%,66.7%,所得共聚物都有较强的荧光性能。P2共聚物在1.3 V处出现氧化掺杂峰,在-1.3 V处出现还原掺杂峰,P3共聚物在0.48 V处出现氧化掺杂峰,0.34 V处出现脱掺杂峰。     

P3HT及CTCHT修饰纳米TiO2的光电性能研究

用光电流作用谱、光电流-电势图等光电化学方法研究了聚3-己基噻吩(P3HT)及3-己基噻吩和2-噻吩甲酸共聚物(CTCHT)修饰纳米结构TiO2电极的光电转换性质。结果表明,经修饰后的纳米TiO2电极光电流明显增强,光电转换效率得到明显提高。在复合膜电极中存在p-n异质结,异质结的存在有利于光生电子-空穴对的分离,降低了电荷的反向复合几率,提高了光电转换效率。     

双重敏感性两亲性聚己内酯混合胶束的合成

合成了两亲性嵌段共聚物聚己内酯(ε-己内酯)-b-聚甲基丙烯酸二乙胺基乙酯和聚乙二醇-二硫键-聚己内酯,用核磁氢谱和凝胶渗透色谱对聚合物的结构及分子量进行了表征。用溶剂挥发法制备了聚合物胶束,用动态光散射以及扫描电镜对胶束结构及性质进行了表征。结果显示,两种聚合物自身可以形成胶束,也可以形成混合胶束;形成的混合胶束粒径在pH小于5.5或pH大于6.5时基本保持稳定,且前者稍大于后者,而在10mmol/L的二硫苏糖醇(DTT)的还原条件下,胶束发生破坏并产生团聚,体现了混合胶束的pH敏感性和还原敏感性,期望能够作为新的药物载体。     

PLGA/PCL复合材料的制备及其性能研究

在聚乳酸-羟基乙酸(PLGA)中加入聚ε-己内酯(PCL)、柠檬酸三丁酯(TBC),通过溶液共混制备了PLGA/PCL共混聚合物,通过静电纺膜及涂膜法制备了不同比表面积的降解膜,并对共混材料力学性能和膜的降解性能进行了研究。结果表明:柠檬酸三丁酯作为增容剂对整个共混聚合物的韧性和强度有明显的影响;当聚乳酸-羟基乙酸和聚ε-己内酯的质量比为80/20、增容剂柠檬酸三丁酯的用量为6%时,所得共混聚合物的断裂伸长率达到130%、冲击强度达到9.55kJ·m-2。相同条件下加入聚ε-己内酯(PCL)的膜的降解性能优于单一的聚乳酸-羟基乙酸(PLGA)膜,静电纺丝膜降解性能优于流延法膜。     

新型聚氨酯微球的合成及其形态研究

通过自乳化的方法合成了具有聚己内酯-聚乙二醇-聚己内酯嵌段结构的聚氨酯水溶液,再采用凝聚相分离法合成了一种新型的聚氨酯微球.研究了聚乙二醇分子量、异氰酸基与羟基的摩尔比、聚己内酯与聚乙二醇的摩尔比、预聚温度、聚氨酯水溶液浓度、CaCl2浓度和搅拌速度等条件对聚氨酯微球的影响,以及傅立叶变换红外光谱(FTIR)和扫描电子显微镜(SEM)表征了微球的化学结构和表面形态结构.通过对合成条件的优化,找出了合成稳定、均匀和形态好的聚氨酯微球的最佳条件.实验结果表明,制备的聚氨酯微球平均粒径2mm左右,分布相对均匀,球形较好.     

热交换器的分类及优缺点分析

热交换器是将不同温度介质之间的热量通过热传导的形式,由高温介质传递给低温介质,使介质达到生产所需温度的工艺设备,也可作为一种节能设备使用.通过对不同热交换器的结构分析,总结不同热交换器的优缺点、适用环境,为生产工艺设计人员及设备制造单位在选择可降低能耗、提高效率的设备上提供参考.     

聚苯胺及其复合物的制备和结构及形貌分析

通过化学氧化法分别制备盐酸,盐酸和十二烷基苯磺酸,碳纳米管(MWNTs-COOH)掺杂的聚苯胺,利用红外光谱,紫外光谱,扫描电子显微镜和透射电子显微镜对所制备聚苯胺的结构和形貌进行分析。分析不同掺杂物对聚苯胺的结构和形貌的影响;同时研究了超声波作用对聚苯胺形貌以及聚苯胺包裹MWNTs-COOH情况的影响。     

Thermodynamic similarity and prediction of the properties and characteristics of substances and processes

Principles of the theory of thermodynamic similarity are considered in application to all aggregate states of a substance, including phase transitions, and to the change in dissipative structures in open systems.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 53, No. 5, pp. 709–716, November, 1987.     

Modelling and computation of curing and damage of thermosets

The curing of thermosets is a complex process involving the transition from a fluid into a (visco-) elastic solid. This phase transition comes along with an increase in stiffness and a volume shrinkage of the polymer. The latter may lead to severe residual strains and stresses, which in turn can cause damage in the final, usually quasi-brittle material. In this contribution a constitutive model is developed which takes into account the curing of a thermosetting material together with the process-induced damage as resulting from curing shrinkage. The curing of the material is governed by a phenomenological hypoelastic constitutive equation which includes temporal evolutions for stiffness and volume shrinkage. Thermal and viscous effects are neglected in the present study. An isotropic gradient-enhanced damage model is adapted to describe the damage evolution. The curing-damage model is implemented into a finite element code and numerical examples for thermosetting materials demonstrate that the proposed model is capable to predict cure-induced damage in thermosets.     

碳化硼陶瓷增韧补强和致密化研究现状及其展望

碳化硼陶瓷具有极高的硬度,然而其低韧性、低抗弯强度、难以致密化限制了它的广泛应用.已有一些研究集中于碳化硼陶瓷增韧补强和致密化,对这一方面国内外研究进展进行了归纳与评述,阐明各种增韧补强和致密化方法的优缺点,提出碳化硼陶瓷增韧补强和致密化研究值得发展的一些方向.     

Measurement and analysis of elastic and anelastic properties of alumina and silicon carbide

Measurements of dynamic Young's modulus, E, and damping as a function of temperature, T, were made for alumina and silicon carbide. The Young's modulus data were compared with some from the literature, and analysed in terms of a theoretical framework relating the Debye temperature, θD, with the elastic constants. For both materials this analysis yielded a ratio T₀/θ_D which was near 0.4, where T₀ is an empirical fitting constant for the plot of (E(0)−E)/T versus 1/T (E(0) is the value of E at 0 K). The analysis of the damping data in terms of an Arrhenius type dependence led to effective activation energies near kT, where k is Boltzmann's constant. This revised version was published online in November 2006 with corrections to the Cover Date.     

Mechanisms of Corosion and Oxidation of Metals and Alloys

Selected topics in field of the study of the mechanisms of corrosion and of oxidation of metals or alloys are presented. The first part reports a new model for the mechanism of the breakaway oxidation of ferritic stainless steels in water vapour. The second part is devoted to the physico‐chemical aspects of oxidation and presents experimental methods useful in the kinetic modelling applied to two alloys, the zircalloy‐4 and an AlMg5 % in the liquid state. In the third part the physical and numerical modelling of the stress corrosion cracking behaviour in face‐centered cubic (fcc) alloys is detailed, which enables the study of the influence of macroscopic parameters (such as the temperature or hydrogen activity) on the fracture process.     

Surface-charge density and potential of coal-liquid mixtures and control of their stability and fluidity

The preparation conditions of concentrated (>70%) aqueous suspensions of coal were optimized, as were the surface charge density and the surface potential of the coal-water suspensions. The theoretical study showed that (1–3) or (2–3) electrolytes such as Na₂SO₄ or Na₅P₃O₁₀, greatly increase the surface charge density and the surface potential of the coal particles in water. This study has led to the interesting result that thinners and stabilizing agents of concentrated clay suspensions, such as lignosulphonates, tripolyphosphates, polynaphtalene sulphonates, etc., must also be good thinners and stabilizing agents for ground coal-water suspensions. Two parameters were controlled: the stability and the fluidity of the suspensions. A penetrometry technique revealed the importance of the resistance coefficient,C _r that can be used as a criterion for the evaluation of coal-water mixture stability and fluidity. Concentrated coal suspensions (about 75% of solid by weight) were prepared in water by using different additives, for instance sodium tripolyphosphate (NaTPP) and surfactants like lignosulphonates (by coupling of the dispersion and stabilizing effects) with the optimum concentration ratio of these two products equal to 1.9. The stability of the suspensions was then greater than 2 months and the viscosity was 1900 cP.     

SARS传染病数学建模及预测预防控制机理研究

首先，利用疾病传播的一般规律及人口守恒统计法则建立了四类人的SARS传染病数学模型，然后运用数学方法对四类人的SARS传染病数学模型进行分析，得出了其生理意义和预防、控制机理。其次，利用人工神经网络理论建立了SARS的预测模型，以北京市的SARS数据为例进行了预测和分析，预测结果显示该模型简单易行，预测精度高。