N-(2-(取代苯并噻唑-2-氨基甲酰基)-取代苯基)-4-氟苯甲酰胺衍生物的合成及生物活性

以对氟苯甲酸和取代邻氨基苯甲酸为起始原料,设计并合成11个含氟基苯并噻唑基邻甲酰氨基苯甲酰胺类化合物,其结构经1 H NMR、13C NMR、IR及元素分析确证.初步生物活性测试结果表明,在500 mg/L浓度下部分化合物对烟草花叶病毒(TMV)有一定抑制作用.采用MTT法进行化合物抑制PC3及Bcap-37癌细胞体外活性测试,结果表明所合成的化合物具有不同程度的抑制PC3和Bcap-37癌细胞活性,其中化合物4d在10 μmol·L-1浓度下对PC3和及Bcap-37的抑制率分别为73.2％和68.1％.     

Ultrasound‐Driven Secondary Self‐Assembly of Amphiphilic β‐Cyclodextrin Dimers

The controlled secondary self‐assembly of amphiphilic molecules in solution is theoretically and practically significant in amphiphilic molecular applications. An amphiphilic β‐cyclodextrin (β‐CD) dimer, namely LA‐(CD)₂, has been synthesized, wherein one lithocholic acid (LA) unit is hydrophobic and two β‐CD units are hydrophilic. In an aqueous solution at room temperature, LA‐(CD)₂ self‐assembles into spherical micelles without ultrasonication. The primary micelles dissociates and then secondarily form self‐assemblies with branched structures under ultrasonication. The branched aggregates revert to primary micelles at high temperature. The ultrasound‐driven secondary self‐assembly is confirmed by transmission electron microscopy, dynamic light scattering, ¹H NMR spectroscopy, and Cu²⁺‐responsive experiments. Furthermore, 2D NOESY NMR and UV/Vis spectroscopy results indicate that the formation of the primary micelles is driven by hydrophilic–hydrophobic interactions, whereas host–guest interactions promote the formation of the secondary assemblies. Additionally, ultrasonication is shown to be able to effectively destroy the primary hydrophilic–hydrophobic balances while enhancing the host–guest interaction between the LA and β‐CD moieties at room temperature.     

Modified cyanate ester resins with lower dielectric loss,improved thermal stability,and flame retardancy

Novel modified cyanate ester (CE) resins with decreased dielectric loss, improved thermal stability, and flame retardancy were developed by copolymerizing CE with hyperbranched phenyl polysiloxane (HBPPSi). HBPPSi was synthesized through the hydrolysis of phenyltrimethoxysilane, and its structure was characterized by ¹H‐NMR, ²⁹Si‐NMR, and Fourier transform infrared spectra. The effect of the incorporation of HBPPSi into CE resin on the curing behavior, chemical structure of cured networks, and typical performance of HBPPSi/CE resins were systemically evaluated. It is found that the incorporation of HBPPSi into CE network obviously not only catalyzes the curing of CE, but also changes the chemical structure of resultant networks, and thus results in significantly decreased dielectric loss, improved thermal stability, and flame retardancy as well as water absorption resistance. For example, in the case of the modified CE resin with 10 wt% HBPPSi, its limited oxygen index is about 36.0, about 1.3 times of that of neat CE resin, its char yield at 800°C increases from 31.6 to 35.4 wt%; in addition, its dielectric loss is only about 61% of that of neat CE resin at 1 kHz. All these changes of properties are discussed from the view of the structure–property relationship. The significantly improved integrated properties of CE resin provide a great potential to be used as structural and functional materials for many cutting‐edges fields. Copyright © 2011 John Wiley & Sons, Ltd.     

A strategy for screening and identifying mycotoxins in herbal medicine using ultra‐performance liquid chromatography with tandem quadrupole time‐of‐flight mass spectrometry

The objective of this study was to develop an effective strategy for screening and identifying mycotoxins in herbal medicine (HM). Here, Imperatae Rhizoma, a commonly used Chinese herb, was selected as a model HM. A crude drug contaminated with fungi was analyzed by comparing with uncontaminated ones. Ultra‐performance LC coupled to tandem quadrupole TOF‐MS (UPLC–Q‐TOF‐MS) with collision energy function was applied to analyze different samples from Imperatae Rhizoma. Then, MarkerLynx^TM software was employed to screen the excess components in analytes, compared with control samples, and those selected markers were likely to be the metabolites of fungi. Furthermore, each of the accurate masses of the markers obtained from MarkerLynx^TM was then searched in a mycotoxins/fungal metabolites database established in advance. The molecular formulas with relative mass error between the measured and theoretical mass within 5 ppm were chosen and then applied to MassFragment^TM analysis for further confirmation of their structures. With the use of this approach, five mycotoxins that have never been reported in HM were identified in contaminated Imperatae Rhizoma. The results demonstrate the potential of UPLC–Q‐TOF‐MS coupled with the MarkerLynx^TM software and MassFragment^TM tool as an efficient and convenient method to screen and identify mycotoxins in herbal materials and aid in the quality control of HM.     

强激光与超音速自由剪切层的相互作用

 以波长为10.6μm,半径0.1m,焦距106m的激光束穿过二维超音速自由射流剪切层流场为物理模型，研究了由于辐射加热强激光束对流场的干扰以及激光束穿过流场后光束远场强度的分布。结果表明：由于流场的存在，使光束的远场强度分布产生了较为明显的变化，对于射流出口处不同的马赫数以及出口压力，流场对光场的远场强度分布影响不同；对于没有引起气体介质电离的强激光束，由辐射加热引起的对超音速自由射流剪切层流场的影响可以忽略。     

PKU-FEL设计的初步考虑

 北京大学在其超导加速器装置PKU-SCAF的基础上将建成一个红外自由电子激光实验平台PKU-FEL。它可以提供高稳定度、高平均功率、高谱纯度、ps脉冲的自由电子激光。给出了PKU-FEL的初步设计方案。     

麻黄素和左旋咪唑显微拉曼测试分析

在可见光激发下，利用显微拉曼技术得到了黄素和左旋旋咪唑的拉曼谱，并将它们的拉曼谱和甲基安非地明做了对比分析，麻黄素和甲基安非他明同属单取代苯，其分子结构十分相似，由于取代基的成分不同一样，因而拉曼谱中一些峰的相对强度和位置发生了变化。左旋咪唑由于取代基上为咪唑亚塞唑，其拉曼谱中主要谱线位置和强度明显不同于麻醉黄素和甲基安非他明。实验结果表明，利用显微拉曼技术在短时间内，对致幻药物进行准确快速的检测分析，将这一技术应用于运动比赛中，有助于对参赛人员服用违禁药物的检测和分析。     

30GHz RF脉冲压缩器设计

为得到脉宽150ns，功率超过100MW的30GHz微波脉冲，采用MSLED-II原理设计了30GHz RF-脉冲压缩器。H-Hybrid，TE100口-TE10o模式转换器等器件都采用了新型设计，所有微波器件的设计充分考虑了高功率下的适用性，没有容易引起打火的调谐杆、容性膜片等部件。在微波器件的设计中用HFSS软件进行了详尽的模拟。加工并测试了H-Hybrid，且用在CERN的RF脉冲展宽器上。     

自适应控制飞行光学聚焦特性

 在对高阶模飞行光学聚焦特性进行研究的基础上，提出了应用自适应飞行光学聚焦系统来解决飞行光学聚焦特性的问题，对自适应飞行光学聚焦系统的调节特性进行了数值模拟，结果表明该系统能够实现对长距离飞行光学激光加工过程中焦点位置与焦斑大小的控制。