基于高介电常数基板和金属结构负折射材料的设计,仿真与验证

通过将单回路镜像对称开口金属环结构印制在高介电常数基板上,实现了一种金属含量比传统负折射材料更少,"双负"通带比全介质负折射材料更宽的负折射材料.分析了高介电常数基板产生负介电常数以及"双负"通带形成的机理,通过仿真实验分析了影响"双负"通带的因素.通过制作样品验证了这一机理实现"双负"的可行性,理论分析与实验结果都表明这种方法可实现较宽频段内的"双负"通带. 关键词： 负折射材料 负介电常数 负磁导率 介质谐振器原理     

Experimental Verification of Left-Handed Metamaterials Composed of Coplanar Electric and Magnetic Resonators

We verified experimentally left-handed metamaterials （LHM） composed of coplanar electric and magnetic resonators. A typical LHM sample composed of coplanar resonator unit cells was fabricated, investigated and tested. The experimental results show that the tested sample has a left-handed band of width 1.4 GHz in the X band. The experimental results agree quite well with the simulation ones. Moreover, both the simulation and experimental results show that the LHM under study can automatically achieve good impedance-matching in the left-handed band.     

瑞香科植物中若干二萜原酸酯的质谱研究

本文系统研究了从瑞香科植物中分得的二萜原酸酪(1～12)的电子轰击质谱反应.这类化合物有相当明确的质谱-结构关系.在阐明裂解机制的基础上,确定了三种新的类似物的结构,它们分别为唐古特瑞香甲素(5)、黄瑞香甲素(6)及15,16-二氢瑞香毒素(13).     

瑞香科植物中若干二萜原酸酯的色谱研究

本文系统研究了从瑞香科植物中分得的二萜原酸酯(1～12)的电子轰击质谱反应,这类化合物有相当明确的质谱-结构关系,在阐明裂解机制的基础上,确定了三种新的类似物的结构,它们分别为唐古特瑞香甲素(5)、黄瑞香甲素(6)及15,16-二氢瑞香毒素(13)。     

缩酚酸醚类化合物的电喷雾多级串联质谱研究

采用电喷雾多级质谱方法, 研究了三个从地衣中提取到的缩酚酸醚类化合物在电喷雾电离质谱中的裂解行为, 结果表明它们在电喷雾多级质谱中能得到较多碎片离子, 其裂解途径能体现它们的基本结构特征.     

喜树碱及其类似物的质谱研究

本文对喜树碱及其类似物进行了质谱研究,阐明了它们在电子轰击下的裂解规律,对同类型新生物碱和药物代谢产物的结构鉴定提供依据。     

锑污染土壤固化-稳定化修复技术研究进展

在对比了几种修复锑污染土壤的方法后,发现固化/稳定化技术是一种成熟有效的处理方法,该技术具有快速、彻底、经济的优点,但存在固化后的锑易被二次活化、后期监测困难、固化后土壤难以二次利用等问题。同时对不同的固化剂、稳定化剂的作用原理进行总结,概述了水泥、石灰/粉煤灰、药剂类对最终修复效果的影响,分析了在土壤理化性质、环境因素影响下锑的再活化行为,提出了应选择高效的试剂、将其与其他修复技术联合使用的研究方向。     

A Method of Analyzing Transmission Losses in Left-Handed Metamaterials

A method of analyzing transmission loss in left-handed metamaterials （LHMs） is proposed. As a demonstration of this method, transmission loss of LHMs composed of split-ring resonators （SRR） and conducting wires is studied. By means of retrieving and analyzing the effective constitutive parameters, different transmission losses as well as their origins are studied. The results show that the left-handed bandwidth is narrowed because of high loss caused by the non-zero high imaginary parts of the effective permeability and permittivity. In the effective left-handed band, the radiation loss is very low and can be neglected, and the transmission losses are the sum of the substrate loss and the ohmic loss. Moreover, when the dielectric loss tangent of the substrate is greater than 0.003, the substrate loss is higher than the ohmic loss.     

All-dielectric left-handed metamaterial based on dielectric resonator: design, simulation and experiment

Dipoles with Lorentz-type resonant electromagnetic responses can realise negative effective parameters in their negative resonant region. The electric dipole and magnetic dipole can realise, respectively, negative permittivity and negative permeability, so both the field distribution forms of electric and magnetic dipoles are fundamentals in designing left-handed metamaterial. Based on this principle, this paper studies the field distribution in high-permittivity dielectric materials. The field distributions at different resonant modes are analysed based on the dielectric resonator theory. The origination and influence factors of the electric and magnetic dipoles are confirmed. Numerical simulations indicate that by combining dielectric cubes with different sizes, the electric resonance frequency and magnetic resonance frequency can be superposed. Finally, experiments are carried out to verify the feasibility of all-dielectric left-handed metamaterial composed by this means.     

2,3-二烷氧基-5-烷氧羰基苄基胺羧酰胺螯合剂的快原子轰击质谱研究

本文报道了运用快原子轰击电离以及快原子轰击-联动扫描方法对2,3-二烷氧基-5-烷氧羰基苄基胺羧酰胺螯合剂的质谱研究, 阐明了它们的裂解途径, 并以此对它和铁离子相螯合后螯合部位进行推测. 结果表明快原子轰击电离方法为金属配合物的研究提供了一种新的手段.