表面羧基化Fe3O4磁性纳米粒子的快捷制备及表征

亲水性磁性纳米颗粒在生物科学领域有着广泛应用,本研究提出了一种快速对磁性纳米粒子表面进行羧基化的方法. 首先使用氯化铁和氯化亚铁为原料, 以油酸为表面活性剂, 通过共沉淀法制得油酸包覆的亲油性磁性纳米粒子, 然后用高锰酸钾进行原位氧化, 将覆盖在粒子表面的油酸中的C＝C键氧化成-COOH, 从而得到单层羧基功能化的亲水性磁性纳米粒子. 利用透射电镜(TEM)、X射线衍射(XRD)、傅利叶红外光谱仪(FT-IR)、热重分析仪(TGA)、振动样品磁强计(VSM)、Zeta电位分析仪等对其进行表征. 结果表明磁性纳米粒子表面被成功羧基化,粒子的平均直径约为9 nm,饱和磁化值为64.5 emu/g,剩磁和矫顽力近似为零,具有典型的超顺磁性. 羧基化磁性纳米粒子可在pH7-10的水溶液中形成稳定分散的磁流体,保存6周无沉淀出现.     

新型3-取代-6-(4-氯苯基)-7-(1H-1,2,4-三唑-1-基)-1',2',4'-三唑[3,4-b]-1",3",4"-噻二嗪衍生物的合成及抗菌活性

通过3-取代-4-氨基-5-巯基-1,2,4-三唑(3a～3m)和2-溴-2-(1H–1,2,4-三唑-1-基)-4′-氯代苯乙酮(2)的缩合反应,合成了13个新型3-取代-6-(4-氯苯基)-7-(1H-1,2,4-三唑-1-基)-1',2',4'-三唑[3,4-b]-1",3",4"-噻二嗪衍生物4a～4m.化合物结构经元素分析,1HNMR,IR和MS进行了表征.抗菌试验表明所合成的化合物对细菌表现出中等程度的抑制活性.     

Selective synthesis of either enantiomer of alpha-amino acids by switching the regiochemistry of the tricyclic iminolactones prepared from a single chiral source

Preparation of l-alpha-amino acids was easily accomplished simply by exchanging the position of the lactone group of our recently reported chiral template 1 from C2 to C3. The new chiral template 7 was prepared in 54% overall yield over five steps from (1R)-(+)-camphor. Alkylation of iminolactone 7 afforded the alpha-monosubstituted products in good yields and excellent diastereoselectivities (>98%). Hydrolysis of the alkylated iminolactones furnished the desired l-alpha-amino acids in good yields and ee with nearly quantitative recovery of chiral auxiliary 4.     

卷绕式铅酸蓄电池板栅材料的研究

0引言制作高功率的卷绕式铅酸蓄电池,目前日益受到广泛关注。薄型极板是卷绕式铅酸蓄电池的显著特点之一。很薄的极板决定着卷绕式铅酸电池的优良性能。制造薄极板的前提是要先制得薄板栅。卷绕式铅酸蓄电池的板栅一方面要起到传统板栅支撑活物质与作为导电电极的作用,另一方面要求这种合金制成板栅后可以卷绕,所以硬度与脆性不能太大。此板栅一般要加工成厚度为0.2￣0.5mm的铅箔。而有报道制得更薄的板栅,厚度达到0.05￣0.08mm,可以说做到了薄如纸[1]。制作这样薄的板栅一般采用压延的方式,首先的问题就是选择何种合金材料,然后是其电化学…     

Chiral tricyclic iminolactone derived from (1R)-(+)-camphor as a glycine equivalent for the asymmetric synthesis of alpha-amino acids

The development of a highly efficient and stereoselective methodology for the preparation of alpha-amino acids is described. The chiral template, tricyclic iminolactone 7, was synthesized from (1R)-(+)-camphor in five steps in 50% overall yield. Alkylation of iminolactone 7 afforded the alpha-monosubstituted products in good yields (74-96%) and excellent diastereoselectivities (>98%). Hydrolysis of the alkylated iminolactones furnished the desired alpha-amino acids in good yields and enantioselectivities with nearly quantitative recovery of the chiral auxiliary 4.     

Semi-stratifiable spaces and the insertion of semi-continuous functions

In this paper, we investigate the relations between the stratifiable structure of spaces and the insertion of semi-continuous functions and give some characterizations of perfect spaces, semi-stratifiable spaces and K-semi-stratifiable spaces.     

Fundamental solution for transversely isotropic thermoelastic materials

We use the compact harmonic general solutions of transversely isotropic thermoelastic materials to construct the three-dimensional fundamental solutions for a steady point heat source in an infinite transversely isotropic thermoelastic material and a steady point heat source on the surface of a semi-infinite transversely isotropic thermoelastic material by three newly introduced harmonic functions, respectively. All components of coupled field are expressed in terms of elementary functions and are convenient to use. Numerical results for hexagonal zinc are given graphically by contours.     

Global smooth solutions for the quasilinear wave equation with boundary dissipation

We consider the existence of global solutions of the quasilinear wave equation with a boundary dissipation structure of an input-output in high dimensions when initial data and boundary inputs are near a given equilibrium of the system. Our main tool is the geometrical analysis. The main interest is to study the effect of the boundary dissipation structure on solutions of the quasilinear system. We show that the existence of global solutions depends not only on this dissipation structure but also on a Riemannian metric, given by the coefficients and the equilibrium of the system. Some geometrical conditions on this Riemannian metric are presented to guarantee the existence of global solutions. In particular, we prove that the norm of the state of the system decays exponentially if the input stops after a finite time, which implies the exponential stabilization of the system by boundary feedback.     

基于“化学信息检索”课程培养学生自主学习能力

从3个方面阐述了利用"化学信息检索"课程培养学生自主学习能力的做法和体会,包括培养学生自主总结信息检索方法,培养学生利用信息检索自主学习专业课程以及自主培养科研能力。     

空心光纤的传光机理及其应用性能的研究

摘要对空心光纤的结构特点做了细致的分析,采用迅衰波场的概念来解释空心光纤纤芯与空心处的传光损耗。同时对空心光纤的衰减特性做了实验研究,得到了空心光纤的衰减常数,并且应用于断裂测量。最后,对空心光纤弯曲、拉伸、压缩等机械性能作了实验研究并做出了解释,为空心光纤应用打下了基础。