Blue electroluminescence from 3,6‐silafluorene‐based copolymers

Poly(3,6‐silafluorene) is a typical wide band‐gap conjugated polymer with ultraviolet light emission. The blue electroluminescence from the 3,6‐silafluorene‐based copolymers via intrachain energy transfer was reported in this study. The monomer containing vinylene, anthracene, and tri‐arylamine moieties incorporated into the poly(3,6‐silafluorene) backbone can form efficient deep‐blue emitting copolymers with EL efficiency of 1.1–1.9%. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3286–3295, 2009     

AFFS技术在大尺寸LCD-TV的进展（英文）

最近我们发展了AFFS技术,做出了32″LED背光源的LCD-TV,色域达到了105%,对比度1200：1,在140°所有视角的对比度达到了100以上,我们采用双轴补偿膜大大提高了颜色漂移的特性。这些光学特性结果的取得是与工艺制作、光学材料的优化、新AFFS像素的设计分不开的。     

32-40GHz 宽带大功率行波管的研究进展

报道了一种32-40GHz 宽带大功率行波管的研究进展情况。在26.5—40GHz 范围内功率大于60 W,增益大于35 dB。功率最大处电子效率大于15%。     

宽禁带半导体功率器件在现代雷达中的应用

现代战争对雷达性能的要求日益提高,基础材料、工艺和元器件的飞速发展,促进了雷达技术的不断进步.宽禁带半导体功率器件的出现,使得雷达发射机乃至雷达性能的大幅度提升成为可能.文中简要介绍了现代雷达对大功率发射机的迫切需求,结合宽禁带半导体器件的特点,阐述了该类器件的发展现状,给出了发展趋势及应用展望.     

宽频带双圆极化单脉冲馈源设计

介绍了一种宽频带双圆极化单脉冲馈源,采用了一种新型馈电方式的单极对数周期天线单元,并利用这种单极对数周期单元以等间距的方式序列馈电,均匀地将8个单极对数周期天线布在一个圆锥上,巧妙地解决了宽频带内的组阵问题。用宽频带双圆极化波束形成网络馈电的该馈源,已成功地应用于某旋转抛物面。实验结果表明,该馈源工作于C波段,具有良好的左/右旋双圆极化和差性能,满足了实际使用的要求,在电子战领域具有很高的应用价值。     

熔锥型宽带保偏光纤耦合器的研究

熔融拉锥型宽带保偏光纤耦合器的制造工艺及其工艺参数的设置,对器件的性能有直接的影响.根据熔融拉锥型宽带保偏光纤耦合器的原理和光纤电磁理论,结合试验事实,对熔融拉锥的工艺进行了总结:实现了常规熔融拉锥型宽带保偏光纤耦合器的制作,并对产品进行了测试,完成了预期研究目标.     

宽量程高时间分辨扫描变像管

 为改善大偏转角度的偏转像质,设计了一种高时间分辨、大扫描长度的扫描变像管电子光学和行波偏转系统。对变像管后加速技术进行了实验研究,结合图像外增强技术,解决了大面积扫描图像的探测灵敏度问题,达到了同时扩展扫描变像管的时间量程和提高时间分辨力的目的,研制出了宽时间量程、高时间分辨力的扫描变像管。初步实验表明,在量程为5 ns时,时间分辨力达到5 ps,也就是时间分辨力与时间量程之比达到1/1 000。     

超广角大工作面f-theta镜头的光学设计

 目前国内用于激光标刻机的f-theta镜头的视场角一般小于60°。采用望远镜结构,利用视觉放大率增大视场角,得到了超广角90°镜头。该方法具有简洁、可靠、易实现等特点。通过初级像差分析,确定系统的初级结构参数,利用ZEMAX软件优化得到了大工作面为285 mm的f-theta镜头,镜头线性畸变误差值不超过1 %,在半径为698 μm的圆内,能量集中度为80%,聚焦性能接近衍射极限。     

Design and implementation of an array of micro-electrochemical detectors for two-dimensional liquid chromatography—Proof of principle

Simultaneous two-dimensional liquid chromatography (2D-LC) is an implementation of two-dimensional liquid chromatography which has the potential to provide very fast, yet highly efficient separations. It is based on the use of time × space and space × space separation systems. The basic principle of this instrument has been validated long ago by the success of two-dimensional thin layer chromatography. The construction of a pressurized wide and flat column (100 mm × 100 mm × 1 mm) operated under an inlet pressure of up to 50 bar was described previously. However, to become a modern analytical method, simultaneous 2D-LC requires the development of detectors suitable for the monitoring of the composition of the eluent of this pressurized planar, wide column. An array of five equidistant micro-electrochemical sensors was built for this purpose and tested. Each sensor is a three-electrode system, with the working electrode being a 25 μm polished platinum micro-electrode. The auxiliary electrode is a thin platinum wire and the reference electrode an Ag/AgCl (3 M sat. KCl) electrode. In this first implementation, proof of principle is demonstrated, but the final instrument will require a much larger array.     

Crystallization and chain conformation of semicrystalline and amorphous polymer blends studied by wide‐angle and small‐angle scattering

We examine the crystallization and chain conformation behavior of semicrystalline poly(ethylene oxide) (PEO) and amorphous poly(vinyl acetate) (PVAc) mixtures with wide‐angle X‐ray diffraction (WAXD), small‐angle X‐ray scattering (SAXS), and small‐angle neutron scattering (SANS) experiments. For blends with PEO weight fractions (wt_PEO) greater than or equal to 0.3, below the melting point of PEO, the WAXD patterns reveal that crystalline PEO belongs to the monoclinic system. The unit‐cell parameters are independent of wt_PEO. However, the bulk crystallinity determined from WAXD decreases as wt_PEO decreases. The scattered intensities from SAXS experiments show that the systems form an ordered crystalline/amorphous lamellar structure. In a combination of WAXD and SAXS analysis, the related morphological parameters are assigned correctly. With the addition of amorphous PVAc, both the average amorphous layer thickness and long spacing increase, whereas the average crystalline layer thickness decreases. We find that a two‐phase analysis of the correlation function from SAXS, in which the scattering invariant is linearly proportional to the volume fraction of lamellar stacks, describes quantitatively the crystallization behavior of PEO in the presence of PVAc. When wt_PEO is close to 1, the samples are fully spaced‐filled with lamellar stacks. As wt_PEO decreases from 1.0 to 0.3, more PVAc chains are excluded from the interlamellar region into the interfibrillar region. The fraction outside the lamellar stacks, which is completely occupied with PVAc chains, increases from 0 to 58%. Because the radius of gyration of PVAc with a random‐coil configuration determined from SANS is smaller than the average amorphous layer thickness from SAXS, we believe that the amorphous PVAc chains still persist with a random‐coil configuration even when the blends form an ordered structure. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2705–2715, 2001