笼型倍半硅氧烷形态分析及对杂化材料相容性和机械性能的影响

采用水解缩合方法制备了八乙烯基笼型倍半硅氧烷(OVPOSS), 并将其引入到聚甲基丙烯酸甲酯(PMMA)自凝树脂中, 得到有机-无机杂化材料. 通过傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、差示扫描量热仪(DSC)、塑料球压痕硬度计、高温高速摩擦磨损测试仪和悬臂梁冲击实验等对其形貌和性能进行了研究. 结果表明, OVPOSS以晶体状态存在于PMMA树脂中. 通过DSC热性能曲线、FOX方程和Gordon-Talyor方程曲线发现, 当POSS含量较高时, PMMA-POSS杂化体系能够发生相分离, 对杂化材料的机械性能有一定的影响.     

A study of electromechanical switching in ferroelectric single crystals

This article documents both modeling and experimental studies developed to investigate the switching behavior of ferroelectric single crystals. The theoretical model makes a priori ansatz that switching follows the evolution of a particular domain pattern. The choice of this configuration is dictated by the requirement that domains remain compatible during evolution, giving rise to a low-energy path for the overall switching. The construction of this pattern is achieved using multirank laminates. It offers an advantage of specifying different types of domain wall movements, leading to a distinction for the switching types. A loading experiment is performed on a barium titanate (BaTiO₃) single crystal with a constant compressive stress and a cyclic electric field. Both 180 and 90 coercive fields are measured as input parameters required for the theoretical framework. The simulation results show good agreement with the observed strains measured by the present and other available experiments. It is found that depolarization has a non-trivial influence on attainable actuation strains.     

数学概念在内涵与外延上的表征

本文提出并论述了数学概念在内涵与外延上的两个表征：（１）结层性；（２）侧综性。同时，还进一步阐明了数学概念的兼容性、非兼容性和反变性。     

AB-交联聚合物(PPU/PS)中分子运动和相容性的固态高分辨NMR研究

本文用固体高分辨NMR技术测量了AB-交联聚合物(即ABCP)PPU/PS(聚氨酯/聚苯乙烯)中侧甲基的¹³C弛豫时间T₁。使用分子内旋转的平均谱密度函数分析了ABCP中CH₃侧基的内旋转运动。结果表明PPU/PS,ABCP中PPU的CH₃侧基运动与PS的含量有关。当体系发生相反转时,侧甲基的运动也发生一转变。这反映了侧甲基的运动与ABCP的宏观性质密切相关。对该ABCP体系还进行了¹H T_1ρ的测量,分析了其相容性。     

胶粉的改性及其在热塑性弹性体中的应用

我国每年产生大量的废橡胶造成了严重的环境污染,作为废橡胶回收再利用的有效途径,胶粉的研究和应用受到广泛关注.本文介绍了胶粉的脱硫再生改性技术与表面活化改性技术及胶粉在热塑性弹性体中的应用,简述了胶粉基热塑弹性体的制备方法并比较了熔融共混法与动态硫化法的区别,概述了各类胶粉基热塑性弹性体的研究现状,着重介绍了胶粉基热塑弹...     

Enzyme-Compatible Core-Shell Nanoreactor for in Situ H2-Driven NAD(P)H Regeneration

The regeneration of the reduced form cofactor NAD(P)H is essential for the extra-cellular application of bio-reduction, which necessitates not only the development of efficient artificial NAD(P)H regeneration catalytic system but also its well compatibility with the cascade enzymatic reduction system. In this work, we reported the preparation of a metal nanoparticle (NP) and metal complex integrated core-shell nanoreactor for H₂-driven NAD(P)H regeneration through the immobilization of a Rh complex on Ni/TiO₂ surface via a bipyridine contained 3D porous organic polymer (POP). In comparison with the corresponding single component metal NPs and the immobilized Rh complex, the integrated catalyst presented simultaneously enhanced activity and selectivity in NAD(P)H regeneration thanks to the rapid spillover of activated H species from metal NPs to Rh complex. In addition, the size-sieving effect of POP precluded the direct interaction of enzyme and Rh complex confined in the pores, enabling the success coupling of core-shell nanoreactor and aldehyde ketone reductase (AKR) for chemoenzymatic reduction of acetophenone to (R)-1-phenylethan-1-ol. This work provides a strategy for the rational manipulation of multicomponent cooperation catalysis.     

Kinetic features of Gualou-Xiebai-Banxia decoction,a classical traditional Chinese medicine formula,in rat plasma and intestine content based on its metabolic profile

Gualou-Xiebai-Banxia decoction (GXB) is a famous classical traditional Chinese medicine (TCM) formula for the treatment of coronary heart disease (CHD, namely chest stuffiness and pain syndrome in Chinese medicine). Compared with Gualou-Xiebai-Baijiu decoction, which only consists of Trichosanthis Pericarpium (TP), Allii Macrostemonis Bulbus (AMB) and wine, GXB comprises one additional herbal medicine, Pinellinae Rhizoma Praeparatum (PRP). However, due to a lack of kinetic profile studies on GXB, its in vivo components with high exposure remain unknown, making it difficult to interpret bioactive components likely linked to its efficacy, but also fails to provide substance-related evidence for reflecting the compatibility in GXB. The goal of this study was to systematically characterize the kinetic features of GXB in rat plasma and intestine content for revealing its in vivo high-exposure components on the basis of their metabolic fates, and to compare the kinetic differences between GXB and GXB-dePRP (GXB deducted PRP) for describing the chemical contribution of PRP to the compatibility in GXB. Firstly, the metabolic profile of GXB was systematically investigated by UPLC-Q/TOF-MS. Subsequently, quantitative methods for representative xenobiotics in rat plasma and intestine content were respectively validated and developed by UPLC-TQ-MS. Then, the established approaches were successfully applied to characterize the kinetic features of GXB through estimating pharmacokinetic parameters. These results showed that only a few kinds of xenobiotics at low exposure levels were observed in plasma, while various xenobiotics possessed high exposure in intestine content. Among them, steroidal saponins and triterpenoid saponins displayed relatively high exposure in plasma and intestine content, which are likely associated with the therapeutic effects of GXB. Moreover, there were no significant differences between metabolic profiles of GXB and GXB-dePRP, whereas the pharmacokinetic parameters, including area under the concentration–time curve (AUC) and C_max (p < 0.05) for most xenobiotics in GXB were significantly larger than those in GXB-dePRP, implying that the introduction of PRP improved the bioavailability of constituents from TP and AMB. Altogether, this study laid a solid foundation and provided theoretical guidance for further clarification of bioactive components of GXB, as well as the synergistic effect of PRP to the compatibility in GXB.