毛细管气相色谱分流进样技术研究

研究出一种改进的毛细管分流进样器，设计了一种新型螺旋进样内衬管。使分流进样的重复精度有显著提高，沸点歧视效应减小，色谱峰尾尖锐，使毛细管色谱柱的高分离效能得以充分发挥。对４种常用的进样内衬进行了考察，得到了有重要实用意义的结果，并从理论上解释了与传统观点相悖的实验现象，深化了对分流进样动态过程的理解。     

Efficiency of quasi-optical couplers

Millimeter-wave devices are often coupled to radiation by means of a feed antenna placed at the focus of a primary lens or mirror, a technique known as quasioptical coupling. A general expression for the efficiency of such a coupler is derived.The efficiency of such a coupler depends on the relationship of the feed antenna pattern to the numerical aperture of the primary lens. An approximate general rule for coupler design is obtained. This rule is as follows. Let _o be the angle between the direction in which the feed pattern is maximum and the direction in which the pattern intensity has one-half its maximum value. Then the optimum numerical aperture of the primary lens is approximately sin (1.67 _o). The effects of focussing errors and lens aberrations can also be calculated by this technique.     

一种分析微带贴片天线的辛时域有限差分方法

文中研究了在时间上采用5级4阶差分、空间上采用4阶差分的高阶辛时域有限差9（SFDTD）数值方法。给出其三维差分公式．将吸收边界条件应用于微带天线的计算中，计算了微带贴片天线的回波损耗及输入阻抗等．计算结果证明，该方法的精确性和正确性．     

一种能产生针状波束和扇形波束的面天线

本文设计出了一种既能产生针状波束又能产生扇形波束的新型面天线,该天线的增益和方向图通过理论计算计算出来。本文设计实例中的面天线的针状波束的E、H平面的半功率宽度分别为2.320、2.240,而扇形波束的E、H平面的半功率宽度分别为2.010,6.40。     

新型套筒天线的研究与应用

采用矩量法分析了安装在金属圆柱筒上的套筒天线.研究了这种新型套筒天线的输入阻抗、电压驻波比(VSWR)、增益及辐射方向图等电特性.设计出了工作在105～420MHz频段和225～600MHz频段的实用天线,分析结果与实验结果吻合良好.     

FDD无线通信系统闭环功率控制发射波束跟踪算法

提出了一种适用于FDD无线通信系统的变步长智能天线下行发射波束跟踪算法.该算法利用闭环功率控制的反馈信息,可自适应地跟踪移动台方位角的变化.算法不需要专门的探测信号,不需要求解信道协方差矩阵,复杂度很低.还分析了功率控制步长对用户方位角跟踪误差的影响.与其它方法相比,新方法具有更小的跟踪误差及更快的收敛速度.     

Wideband to narrowband/dual band characteristics of monopole antenna using frequency selective surfaces

A monopole antenna having desirable transmission characteristics with high gain is proposed. The monopole antenna comprises 45° tilted square shaped patch and modified rectangular metallic ground plane on FR4 dielectric substrate. The proposed monopole antenna operates from 2.6 GHz to 9.7 GHz with maximum peak gain of 2.3 dBi. Now, a dual-layer aperture-type FSS is designed having a passband from 5.9 GHz to 9.2 GHz and incorporated with the proposed monopole antenna. Thus, the combination only covers the selective frequency band from 5.5 GHz to 8.7 GHz with a stable gain of around 5 dBi. Second, another FSS is designed, which has one stop-band from 4.1 GHz to 5.4 GHz and two passbands on the both sides of this stop-band. This combination does not work from 4.1 GHz to 5.5 GHz but covers dual band from 2.48 GHz to 3.3 GHz with a peak gain of 5 dBi and 5.5 GHz to 10 GHz with a peak gain of 5.5 dBi. Therefore, without modifying the antenna design, any tunable transmission band can be achieved by the proposed combination. The proposed antenna and FSS combination structure may be suitable for military wireless applications for its band selection characteristics.     

Casimir Effect Under Two Dimensional Black Hole Spacetime Background with Global Monopole

A thin layer of the event horizon vicinity to the two-dimension black hole with a global monopole is considered as a system of the Casimir type. The energy-momentum tensor is derived in Boulware vacuum, Hartle-Hawking vacuum and Unruh vacuum respectively. The values are derived in the massless scalar field which satisfies the Dirichlet boundary conditions. Using the Wald's axioms, the result is got which is the same with the one derived by the usual regularized methods. Meanwhile, the energy, energy density, and pressure acting on the boundaries at the asymptotically flat background also are calculated too, and from the energy, Casimir force is derived. The Casimir energy and Casimir force are compared respectively in the background before and after radiation. PACS: 42.50.Lc.     

覆盖高εr材料微带天线的研究

采用高介电常数(εr=38)的陶瓷材料制作矩形微带天线，体积缩小了很多，但增益下降。若用更高εr材料的覆盖层，在900MHz和1．8GHz频率实验表明，增益得到明显提高。     

Design of Arbitrarily Controlled Multi-Beam Antennas via Optical Transformation

The design of arbitrarily controlled multi-beam antennas is investigated by using the technique of optical transformation. Based on the optical transformation, cylindrical waves emitted from a line source can be converted to plane waves through a metamaterial layer which has a circular shape in the inner outline and a polygon shape in the outer outline. Hence the line source together with the metamaterial layer constructs a high-performance multi-beam antenna. The number of sidelines and the shape of polygon are used to control the number and directions of beams. Analytical formulas of the permittivity and permeability tensors are presented for the metamaterial layer in the antenna. The designed multi-beam antennas are validated by full-wave simulations using the finite-element method. The proposed multi-beam antennas will be very useful in the intelligent traffic system.