TPU增韧MABS的研究

利用双螺杆挤出机制备聚氨酯和甲基丙烯酸甲酯—丙烯腈-丁二烯-苯乙烯树脂熔融共混物(合金)。研究TPU的类型以及含量对TPU/MABS合金的透光率、力学性能和缺口冲击强度影响。结果表明:TPU/MABS合金可以保持较好透明性,随TPU含量的增加,合金材料的拉伸强度和弯曲模量逐渐降低,但是合金材料的冲击强度得到明显提高。扫描电镜观察表明,随TPU含量的增加,TPU与MABS界面分离现象逐渐明显。同时发现聚醚型TPU与MABS相容性和增韧效果要优于聚酯型TPU。     

Saturated control design for linear differential inclusions subject to disturbance

In this paper, saturated control design method is presented for robust stabilization of linear differential inclusions subject to disturbance. Convex hull quadratic Lyapunov functions are used to construct nonlinear state feedback laws. By the state feedbacks, stabilization, disturbance rejection with minimal reachable set and least L ₂ gain are achieved simultaneously. Finally, the effectiveness of the proposed scheme is illustrated by a simulative example.     

废水中铜银的分离和银的回收研究

废水中铜银的分离和银的回收研究黄秀山（四川三峡学院化学系万县６３４０００）关键词分解电压，还原电势，回收一、引言本实验采用电解还原的方法回收贵金属银。目前此法主要用于回收废水中的铬、汞等，对银的研究很少。曾有人进行过自然渗析还原法回收银的研究。用自然...     

N,N（二甲庚基）乙酰胺萃钯机理研究

本文研究了N,N二甲庚基乙酰胺(N_(s03))从氯化物体系中萃取钯的机理。应用等摩尔系列法和斜率法确定萃合物组成为:(CH_3CONR_2H)_2PdCl_4。通过紫外-可见光谱法研究,证实N_(503)萃取钯的机理属阴离子交换反应,其萃取方程式为: 2CH_3CONR_2HCl_((o)) PdCl_4~(2-)(a)?(CH_3CONR_2H)_2PdCl_4(o) 2Cl~-(a)     

水性聚氨酯乳化过程中相转变的研究

本文合成了单官能团小分子物质封端的脂肪族水性聚氨酯预聚物 ,通过考察预聚物加水乳化过程中粘度及电导率的变化 ,研究了其相转变行为 .实验结果表明 ,随着软段分子量升高 ,体系的相转变点后延 ;聚酯体系的相转变比聚醚体系的相转变发生得早 ;[NCO]/ [OH]值越接近 1,体系的粘度就越高 ,相转变发生所需的水含量也越高 ;羧基含量及中和度也会对分散体系的相转变产生影响 .通过选择合适的条件 ,可以实现对乳化过程的优化     

Phase behavior, rheological property, and transmutation of vesicles in fluorocarbon and hydrocarbon surfactant mixtures

We present a detailed study of a salt-free cationic/anionic (catanionic) surfactant system where a strongly alkaline cationic surfactant (tetradecyltrimethylammonium hydroxide, TTAOH) was mixed with a single-chain fluorocarbon acid (nonadecafluorodecanoic acid, NFDA) and a hyperbranched hydrocarbon acid [di-(2-ethylhexyl)phosphoric acid, DEHPA] in water. Typically the concentration of TTAOH is fixed while the total concentration and mixing molar ratio of NFDA and DEHPA is varied. In the absence of DEHPA and at a TTAOH concentration of 80 mmol·L(-1), an isotropic L(1) phase, an L(1)/L(α) two-phase region, and a single L(α) phase were observed successively with increasing mixing molar ratio of NFDA to TTAOH (n(NFDA)/n(TTAOH)). In the NFDA-rich region (n(NFDA)/n(TTAOH) > 1), a small amount of excess NFDA can be solubilized into the L(α) phase while a large excess of NFDA eventually leads to phase separation. When NFDA is replaced gradually by DEHPA, the mixed system of TTAOH/NFDA/DEHPA/H(2)O follows the same phase sequence as that of the TTAOH/NFDA/H(2)O system and the phase boundaries remain almost unchanged. However, the viscoelasticity of the samples in the single L(α) phase region becomes higher at the same total surfactant concentration as characterized by rheological measurements. Cryo-transmission electron microscopic (cryo-TEM) observations revealed a microstructural evolution from unilamellar vesicles to multilamellar ones and finally to gaint onions. The size of the vesicle and number of lamella can be controlled by adjusting the molar ratio of NFDA to DEHPA. The dynamic properties of the vesicular solutions have also been investigated. It is found that the yield stress and the storage modulus are time-dependent after a static mixing process between the two different types of vesicle solutions, indicating the occurrence of a dynamic fusion between the two types of vesicles. The microenvironmental changes induced by aggregate transitions were probed by (19)F NMR as well as (31)P NMR measurements. Upon replacement of NFDA by DEHPA, the signal from the (19)F atoms adjacent to the hydrophilic headgroup disappears and that from the (19)F atoms on the main chain becomes sharper. This could be interpreted as an increase of microfluidity in the mixed vesicle bilayers at higher content of DEHPA, whose alkyl chains are expected to have a lower chain melting point. Our results provide basic knowledge on vesicle formation and their structural evolution in salt-free catanionic surfactant systems containing mixed ion pairs, which may contribute to a deeper understanding of the rules governing the formation and properties of surfactant self-assembly.     

小浪底工程中的关键力学问题

黄河小浪底工程规模宏大，地理位置重要、地质条件复杂、运用要求严格、水沙条件特殊，被称为世界上最具挑战性的水利工程之一，坝址区复杂的地质和黄河高含沙水流是小浪底工程技术复杂的主导因素，在土力学和土动力学、岩石力学、结构力学和结构动力学、水工水力学等多个力学领域中解决了关键技术问题，在一定程度上推动了工程力学中的试验分析方法和分析手段的发展。