Ferric nitrate-catalyzed aerobic oxidation of benzylic sp3 CH bonds of ethers and alkylarenes

A simple catalytic oxidation system was developed for the selective aerobic oxidation of structurally diverse benzylic sp³ CH bonds of ethers and alkylarenes. The reactions were performed with Fe(NO₃)₃·9H₂O as the catalyst, KPF₆ as the additive and molecular oxygen as the terminal oxidant without any ligands. Under the optimal reaction conditions, a number of isochromans, xanthenes and thioxanthenes can be converted to their corresponding esters or ketones in good to excellent yields.     

反应性高分子抗菌剂的合成及对棉织物的抗菌整理

通过三元共聚将马来酸酐活性基团引入大分子链中,制备了两个系列的反应性高分子抗菌剂poly(DMAEMA-BC/AAm/MAn)和poly(DMAEMA-DB/AAm/MAn),并用FT-IR对合成的反应性高分子抗菌剂进行了结构表征,用酸碱滴定法测定了其酸值,通过平板活菌计数法测定了反应性高分子抗菌剂的抗菌活性,并表征了它们的抗菌活性对抗菌时间与浓度的依赖关系。通过热整理工艺将三元共聚物与棉织物反应,制得抗菌织物。之后,通过改良振荡烧瓶法测定了抗菌整理后棉织物的抗菌效果,并进一步考察了织物抗菌效果的耐洗性。研究结果表明,少量的马来酸酐(单体摩尔比5%)有助于提高共聚单体的反应活性,共聚物中含少量马来酸酐时,抗菌活性增强。用马来酸酐单体摩尔比5～35%的poly(DMAEMA-BC/AAm/MAn)或5～25%的poly(DMAEMA-DB/AAm/MAn)整理的抗菌织物均具有良好的抗菌效果,且前者经过100次水洗,后者经200次水洗后,仍表现良好的抗菌效果。     

A facile protocol for the synthesis of mono-N-methyl anilines via formimidate intermediates

A general procedure for the preparation of mono-N-methyl anilines has been developed with excellent yields. This protocol relies on a NaBH₃(OAc) reduction of formimidate intermediates that are quantitatively generated by treatment of primary substituted anilines with triethyl orthoformate under the catalysis of MCM-41-SO₃H mesoporous zeolite. The newly developed procedure was facile, efficient, and environmentally benign.     

新雌激素衍生物的合成及抗辐射升白生物活性

以17α-炔雌二醇和17β-雌二醇为原料,分别与烯丙基溴、溴代异戊烯反应,通过一步反应合成了4个新雌激素衍生物,分别是17α-炔雌二醇-3-烯丙基醚(ES-1),17β-雌二醇-3-烯丙基醚(ES-2),17α-炔雌二醇-3-异戊烯基醚(ES-3)和17β-雌二醇-3-异戊烯基醚(ES-4),产率分别为92.2%,73.7%,65.9%和67.6%.化合物通过1HNMR,13CNMR,IR,MS及元素分析确证了结构,4个化合物均未见文献报道.初步的抗辐射升白生物活性研究表明,4个化合物对137Csγ-射线引起的小鼠白细胞低下及造血系统功能损伤有一定的保护作用.其中ES-3的升白作用最佳,经统计学处理,3个给药剂量组与对照组比,升白作用均有非常显著性差异(P0.001).     

基于艳原子线性法拉第磁光效应的应用

分析了(銫) (Cs)原子作为旋光介质的线性法拉第磁光效应.采用二能级模型解释了(銫)原子与光的相互作用,并利用琼斯矩阵推导了当激光器的频率处于(銫)原子共振线时,经过(銫)气室的线偏振光的旋转角与外加磁场的关系式,利用此关系式可测量磁场强度的大小和气室内(銫)原子的浓度.实验采用852nm分布反馈半导体激光器作为光源...     

基于光子筛的软X光谱仪

 介绍了采用新型软X光谱学光子筛作为分光元件的软X光谱仪的原理和结构参数设计。新谱仪理论测量范围为100 eV~2 keV,光谱分辨力达0.35 nm。应用该谱仪在SILEX-Ⅰ装置上测量了飞秒激光与固体铜靶相互作用产生的X射线发射谱。实验结果表明,该谱仪主要性能指标达到设计要求,适合于激光与等离子体相互作用产生的软X射线研究。     

可见区分光光度法测量水体色度

针对目前水质色度测量方法的局限性,采用分光光度法测量相关色度学参数,通过色度学参数与国家标准方法的色度值建立数值关系,从而测定水体的色度值.该方法不仅保证测量结果与现行国家标准测量结果一致,而且客观性强,稳定可靠,灵敏度更高,也更准确.克服了目视比色法需要水体与标准溶液色调一致的局限性,可以推广到其他色调的废水色度测量...     

Studies on the mechanisms of powerful terahertz radiations from laser plasmas

A survey on the mechanisms of powerful terahertz (THz) radiation from laser plasmas is presented.Firstly,an analytical model is described,showing that a transverse net current formed in a plasma can be converted into THz radiations at the plasma oscillation frequency.This theory is applied to explain THz generation in a gas driven by two-color laser pulses.It is also applied to THz generation in a tenuous plasma driven by a chirped laser pulse,a few-cycle laser pulse,a DC/AC bias electric field.These are well verified by particle-in-cell simulations,demonstrating that THz radiations produced in these approaches are nearly single-cycles and linear polarized.In the chirped laser scheme and the few-cycle laser scheme,THz radiations with the peak field strength of tens of MV/cm and the peak power of gigawatt can be achieved with the incident laser intensity less than 10 17 W/cm 2.     

Morphological and ultrastructural characterization of the alimentary canal in Japanese wax scale (Ceroplastes japonicus Green)

The morphology and ultrastructure of the alimentary canal in the adult female of the Japanese wax scale, Ceroplastes japonicus Green (Hemiptera: Coccoidea: Coccidae), was investigated using light microscopy, scanning electron microscopy and transmission electron microscopy. The results showed that the foregut was subdivided into a sclerotized pharynx and an oesophagus. A pair of salivary glands attached in the middle of the foregut. The loop-shaped midgut was narrow and longer than the foregut and its inner wall lined with a thick layer of epithelia. The hindgut was divided into a narrower ileum and a broader rectum, with the well-developed filter chamber enclosed in the anterior rectum. Malpighian tubules consisted of two brownish-yellow moniliform tubules with pores, approximately 1 μm in diameter, scattered on the outer surface and many spherical crystals inside the tubules.     

Discontinuous Galerkin methods for solving a quasistatic contact problem

We consider the numerical solution of a nonlinear evolutionary variational inequality, arising in the study of quasistatic contact problems. We study spatially semi-discrete and fully discrete schemes for the problem with several discontinuous Galerkin discretizations in space and finite difference discretization in time. Under appropriate regularity assumptions on the solution, a unified error analysis is established for the schemes, reaching the optimal convergence order for linear elements. Numerical results are presented on a two dimensional test problem to illustrate numerical convergence orders.