一种嵌入式关系模型的形式化描述

在 Ｎ Ｒ／ Ｔ 网的基础上,对基于嵌入式关系模型的数据库信息系统的行为,给出了一种形式化的描述方法,并设计了一个变迁点火执行算法     

三元乙丙橡胶的13C-NMR定量分析

用13C核磁共振波谱法对三元乙丙橡胶进行了研究，通过图谱中各个峰的积分值，并用特定的计算公式测定了三元乙丙橡胶中乙烯及第三单体乙叉降冰片烯的含量，为红外光谱批量的定量分析建立了基准化的标定。     

强激光场中氘团簇的离子能谱与团簇尺度

在SILEX-Ⅰ装置上进行了超短超强激光与氘团簇相互作用的实验。采用法拉第筒测量了激光与氘团簇靶相互作用后发射出的氘离子能谱,并根据氘离子能谱计算出氘团簇的尺寸和分布。由于激光预脉冲的影响,得到了团簇的尺度比瑞利散射测量的结果小。这些结果对团簇源制备系统的改进和优化激光打靶有着重要的参考意义,而且可以为团簇尺度的测量提供一种新的方法。     

同位素示踪法的开创者——赫维西

19世纪末20世纪初是物理化学和生物化学发展的重要时期,同位素示踪法在一系列示踪剂实验方面取得了许多成就。瑞士籍匈牙利裔化学家乔治·德·赫维西(1885—1966)将示踪技术应用到生物学领域,他有关同位素示踪法的发明也使其获得了1943年诺贝尔化学奖。本文对赫维西生平及学术成长历程进行介绍,反映了赫维西的成长与欧洲当时的诸多科学家之间的学术往来是不可分割的。     

Determination of six polyynes in Oplopanax horridus and Oplopanax elatus using polyethylene glycol modified reversed migration microemulsion electrokinetic chromatography

A PEG‐modified reversed migration MEEKC method was developed for simultaneous determination of six polyynes, including oplopandiol, falcarindiol, oplopandiol acetate, (11S, 16S, 9Z)‐9,17‐octadecadiene‐12,14‐diyne‐1,11,16‐triol,1‐acetate, oplopantriol B, and oplopantriol A, in Oplopanax horridus and Oplopanax elatus. The running buffer containing 0.8% v/v ethyl acetate, 3.8% w/v SDS, 6.6% v/v n‐butanol in 20 mM phosphate buffer (pH 2.5), followed by mixing with propan‐2‐ol at 30% v/v and PEG‐1000 at 15% w/v, was applied in the analysis. The proposed method was successfully applied to determine the six polyynes in five samples of Oplopanax horridus and one of O. elatus. The result showed that the types and amounts of polyynes present were obviously different when comparing the two herbs. Besides, the developed PEG‐modified reversed MEEKC method might be suitable for the analysis of hydrophobic analytes in herbal medicines.     

一种紧凑型高功率宽带微波源

设计了一种高功率宽带微波辐射装置,谐振器采用传输线型谐振器,其中,天线采用单锥喇叭。整个宽带微波产生装置具有结构紧凑、谐振频率较低的特点。用时域有限差分对该装置进行了数值模拟,模拟结果为：辐射场中心频率272 MHz,带宽13.5%。装置与高压脉冲源联试,开关内充电电压为71 kV时,辐射场中心频率为197 MHz,辐射场带宽达到24%,峰值辐射因子为28.3 kV。     

Influence of substituent groups at the 3‐position on the mass spectral fragmentation pathways of cephalosporins

The structural fragment ions of nine cephalosporins were studied by electrospray ionization quadrapole trap mass spectrometry (Q‐Trap MSⁿ) in positive mode. The influence of substituent groups in the 3‐position on fragmentation pathway B, an α‐cleavage between the C7? C8 single bond, coupled with a [2,4]‐trans‐Diels‐Alder cleavage simultaneously within the six‐membered heterocyclic ring, was also investigated. It was found that when the substituent groups were methyl, chloride, vinyl, or propenyl, fragmentations belonging to pathway B were detected; however, when the substituents were heteroatoms such as O, N, or S, pathway B fragmentation was not detected. This suggested that the [M–R₃]⁺ ion, which was produced by the bond cleavage within the substituent group at the 3‐position, had a key influence on fragmentation pathway B. This could be attributed to the strong electronegativity of the heteroatoms (O, N, S) that favors the production of the [M–R₃]⁺ ion. Moreover, having the positive charge of the [M–R₃]⁺ ion localized on the nitrogen atom in the 1‐position changed the electron density distribution of the heterocyclic structure, which prohibits a [2,4]‐reverse‐Diels‐Alder fragmentation and as a result fragmentation pathway B could not occur. The influence of the substituent group in the 3‐position was determined by the intensity ratio (e/d) of ions produced by fragmentation pathway A, a [2,2]‐trans‐Diels‐Alder cleavage within the quaternary lactam ring, including the breaking of the amide bond and the C6? C7 single bond (ion d), and fragmentation pathway B (ion e). The results indicate that the electronegativity of the substituent group was a key influencing factor of pathway B fragmentation intensity, because the intensity ratio (e/d) is higher for a chlorine atom, a vinyl, or a propenyl group than that of a methyl group. This study provided some theoretical basis for the identification of cephalosporin antibiotics and structural analysis of related substances in drugs. Copyright © 2010 John Wiley & Sons, Ltd.     

随机耦合模型在高功率微波效应中的应用

分析了微波混沌腔体系统中关键部位感应电压的统计问题,介绍了随机耦合模型在高功率微波效应研究中的计算方法和应用,并以计算机机箱为实验系统,开展了电磁波耦合入计算机机箱腔体的电磁干扰问题研究,对其电路板上关键部位感应电压的统计计算和实验结果进行了比较,其结果基本一致。随机耦合模型在波混沌系统中感应电压的统计探讨为高功率微波效应、电磁兼容等研究提供了一种新的思路。     

1 MA直线型变压器驱动源模块设计

介绍了输出电流幅值为1 MA,电流上升时间为100 ns的快脉冲直线型变压器驱动源（LTD）模块的设计。模块由48个子块并联组成,每个子块由2个电容器和一个多级气体开关串联组成。48个开关由8路高压脉冲触发,每路高压脉冲（100 kV/50 ns）触发6个开关。电路模拟显示,在充电 90 kV条件下,输出电流幅值为1.04 MA,电流上升时间为84.5 ns（0~100%）和52 ns（10%~90%）。电路模拟时的参数设置以实验数据为基础,开关的工作条件与已研制成功的100 kA-LTD模块中的开关工作条件近似,模块设计工作于腔体注油状态以保证高压运行安全,能够保证模块达到设计要求。     

感应电压叠加器模块对方波脉冲的响应

为了解感应电压叠加器（IVA）对馈入脉冲的响应特性,尤其对上升前沿、平顶的影响,从理论和实验两个方面对IVA模块进行了研究。介绍了IVA的工作原理,利用集总参数方法建立了相应的电路模型,通过拉普拉斯变换分析了感应电压叠加器对方波脉冲上升前沿和平顶的响应,并在一个特定的IVA模块上进行了实验研究。选择输出阻抗约1.2 Ω、脉宽约1 μs的脉冲形成网络作为馈源,在匹配负载上得到的波形与输入波形在幅值、上升前沿方面达到了很好的吻合,平顶出现略微的顶降,与理论预期相一致。