端炔与对亚甲基苯醌的1,6-加成

为了合成selaginellin家族天然产物,我们开发了炔锂和对亚甲基苯醌的1,6-加成反应。研究了此反应的反应条件及底物适用范围和限制。结果表明,对亚甲基苯醌苯环上的取代基对反应速率和产率有显著的影响:吸电子基团增加其亲电性,使反应变快,并且可以得到较高的产率;与此相反,给电子基团则降低了对亚甲基苯醌的亲电性,反应变慢,并且表现出可逆性,产率变低。端炔对反应影响很小,均能得到高产率的产物。本方法可用于快速构建selaginellin家族天然产物的骨架结构。     

Expression and Characterization of an Active Chimeric Protein of Human Extracellular Superoxide Dismutase and hCuZnSOD in Pichiapastoris

Mammalian cells express two isoforms of Cu-and Zn-containing superoxide dismutases(SODs),CuZnSOD and extracellular SOD(EC-SOD),involved in the defense system against reactive oxygen species(ROS).The two SODs have structurally homologous centre domain with distinct N-and C-terminuses,resulting in the different characteristics of the structure and function of the two molecules.We generated a hybrid SOD molecule(namely hySOD) via replacing the N-and C-terminuses of hCuZnSOD with the counterparts of hEC-SOD.The...     

THEORY OF DIELECTRIC ELASTOMERS

In response to a stimulus, a soft material deforms, and the deformation provides a function. We call such a material a soft active material （SAM）. This review focuses on one class of soft active materials： dielectric elastomers. When a membrane of a dielectric elastomer is subject to a voltage through its thickness, the membrane reduces thickness and expands area, possibly straining over 100%. The dielectric elastomers are being developed as transducers for broad applications, including soft robots, adaptive optics, Braille displays, and electric generators. This paper reviews the theory of dielectric elastomers, developed within continuum mechanics and thermodynamics, and motivated by molecular pictures and empirical observations. The theory couples large deformation and electric potential, and describes nonlinear and nonequilibrium behavior, such as electromechanical instability and viscoelasticity. The theory enables the finite element method to simulate transducers of realistic configurations, predicts the efficiency of electromechanical energy conversion, and suggests alternative routes to achieve giant voltage-induced deformation. It is hoped that the theory will aid in the creation of materials and devices.     

单体性质对樟脑醌/胡椒环光引发活性的影响

采用实时红外光谱仪(RT-FTIR)研究了单体结构、单体配比以及活性稀释剂结构对樟脑醌(CQ)/胡椒环(BDO)引发的光聚合动力学的影响,结果发现,UDMA虽然黏度较低,但是易发生链转移反应且在聚合体系中含量较高(70 wt%),可作为氢给体猝灭激发态CQ,从而影响CQ和BDO之间的相互作用.Bis-GMA虽然黏度大,但是反应活性高,当其与少量具有给氢能力的活性稀释剂TEGDMA配合使用时,不仅对聚合体系的反应活性影响较小,而且可显著降低体系的黏度,大大提高自由基的活动能力,有利于改善CQ/BDO的引发活性.     

茶汤抗氧化活性的测定综合化学实验的研究

实验以潮州工夫茶文化为背景,在工夫茶传统冲泡工艺的基础上,采用茶汤抗氧化活性为评判指标,探讨工夫茶冲泡工艺的优化条件.实验内容包括文献调研、实验方案设计、实验操作、数据处理及小论文撰写等一系列学习任务.实践教学结果表明,将传统茶文化融入实验教学中,易于激发学生的学习兴趣,传递文化基因;引导学生从文化生活源头提出问题,运用科学方法分析问题、解决问题,利于学生熟悉科学过程,养成正确的科学思维习惯;同时,实践活动中学生会触及到多个学科领域、多重实验操作技能训练,可以全面提升学生的综合素养,达成课程育人目标.     

Pure Multiplicative Noises Induced Population Extinction in an Anti-tumor Model under Immune Surveillance

The dynamical characters of a theoretical anti-tumor model under immune surveillance subjected to a pure multiplicative noise are investigated. The effects of pure multiplicative noise on the stationary probability distribution （SPD） and the mean first passage time （MFPT） are analysed based on the approximate Fokker-Planck equation of the system in detail. For the anti-tumor model, with the multiplieative noise intensity D increasing, the tumor population move towards to extinction and the extinction rate can be enhanced. Numerical simulations are carried out to check the approximate theoretical results. Reasonably good agreement is obtained.     

亚微米分子筛粒径与性能的关联研究

对实验室合成的不同粒径的NaY分子筛进行了性能研究,表明比表面积、酸量随着粒径的减小而增加,粒径太小的分子筛其稳定性、活性低,不能满足FCC催化剂的使用要求,应用于FCC催化剂的分子筛合适粒径为500nm～800nm.     

超强激光超热电子激发的Kα X射线发射研究

建立了无色散型X射线谱仪. 利用SILEX-I激光装置的超强激光辐照固体物质，分别在靶前、后定量测量了Cu和Mo物质在不同激光功率密度时的X射线谱和Kα光子产额，推导了不同激光强度时的Kα X射线光子转换效率. 实验发现，打靶激光能量越高，靶后出射的Kα产额越高，100μm Mo靶可获得10^-5量级转换效率.     

Eu2+,Mn2+在BaZnP2O7中的发光及Eu2+→Mn2+能量传递

采用高温固相法合成了BaZnP₂O₇:Eu²⁺,Mn²⁺荧光粉，并对其发光性质及Eu²⁺对Mn²⁺的能量传递机理进行了研究.Eu²⁺和Mn²⁺在380 nm和670nm的发射峰分别由Eu²⁺的5d—4f跃迁和Mn²⁺的⁴T₁(^{4相似文献}   

材料学科研究进展

1核材料 金属铀及合金广泛应用于核工程，金属铀及合金的性能、与活性介质的作用、表面防护一直是备受关注的问题。主要开展了铀及合金的动态性能、加工工艺及表面性能表征研究，取得了明显进展。