G.652光纤长途传输系统的色散补偿

针对当前国内长途传输光缆系统在扩容过程中，因光信号色散而影响传输质量的现象，结合实际工程建设，分析了光信号色散的危害及其成因，并提出了相应的解决办法及建议。     

Stabilization of bioethanol recovery with silicone rubber‐coated ethanol‐permselective silicalite membranes by controlling the pH of acidic feed solution

In order to produce highly concentrated bioethanol by pervaporation using an ethanol‐permselective silicalite membrane, techniques to suppress adsorption of succinic acid, which is a chief by‐product of ethanol fermentation and causes the deterioration in pervaporation performance, onto the silicalite crystals was investigated. The amount adsorbed increased as the pH of the aqueous succinic acid solution decreased. The pervaporation performance also decreased with decreasing pH when the ternary mixtures of ethanol/water/succinic acid were separated. Using silicalite membranes individually coated with two types of silicone rubber, pervaporation performance was significantly improved in the pH range of 5 to 7, when compared with that of non‐coated silicalite membranes in ternary mixtures of ethanol/water/succinic acid. Moreover, when using a silicalite membrane double‐coated with the two types of silicone rubber, pervaporation performance was stabilized at lower pH values. In the separation of bioethanol by pervaporation using the double‐coated silicalite membrane, removal of accumulated substances having an ultraviolet absorption maximum at approximately 260 nm from the fermentation broth proved to be vital for efficient pervaporation. Copyright © 2005 Society of Chemical Industry     

Growth and optical property of zinc oxide thornballs

A new microstructure, thornball, of zinc oxide (ZnO) was synthesized by a very simple solid vapor deposition process under lead oxide (PbO) atmosphere. The microthornballs consist of numerous needles, which extend outwards in all directions symmetrically. They have dimensions of 120 μm in diameter, while the average diameter of the needles is about 100-200 nm. The needles on the balls grow along the 〈0 0 0 1〉 orientation and have gradient compositions along radial. Control experiments proved that PbO played an important role in the growth. Additionally, photoluminescence property was observed and provided the evidence that PbO did not deteriorate the optical properties of ZnO thornballs. This kind of microstructures has potential applications in the field of photochemical catalysis.     

Apparent versus true density for the volume-to-weight transformation in coal blends

This work reviews the procedures involved in the conversion of the petrographic characterization data of blended coals into weight percentages of the single coals in the blends, the selection of the most suitable parameter for describing the density of the coals being critical. First, the fundamentals of the volume-to-weight transformation of the petrographic data were developed by means of mathematical formulae. This part of the procedure highlighted the need to use a density value adapted to the resolving power of the optical microscope. It was found that mercury penetration at 5 MPa, as determined by mercury porosimetry, was best suited for this purpose. A literature survey of published coal density data revealed that the use of correlations between coal density and rank was not an accurate enough procedure to deal with the relatively low corrections involved in the transformation of petrographic data. In the end, three binary blends were prepared from six carefully selected coals and polished particulate blocks of these blends were petrographically analysed to determine their compositions on a volume per cent basis. The best fit of these volume percentages with the weight percentages used in the formulation of the blends was found for a density correction based on mercury penetration at 5 MPa, in agreement with the empirical analysis.     

Advanced modulation formats for more robust optical transmission systems

Interest in advanced modulation formats for optical communication systems has so far experienced two major waves. The first one was motivated by the potential to enhance receiver sensitivity of thermal noise-limited systems using coherent detection in combination with phase shift keying. It ended with the advent of optical amplification, enabling high sensitivities together with polarization insensitive, simple and stable direct detection. The second wave is still rolling, fueled by the potential of advanced modulation formats to increase robustness of optical transmission systems against signal distortions. Due to performance limitations given by direct detection and nonlinear effects in the transmission fiber, it is not decided yet, whether there will be widespread application in carrier networks.     

Enhanced Image Detection on an ARM based Embedded System

This paper presents a new technique for thedetection of Integrated Circuits within images of Printed Circuit Boards autonomouslyand without the need to be assisted by CAD data. The technique is a key partof a suite of algorithms targeted for an embedded System On Chip architecturebased on the ARM7 platform for real time detection of PCB images for diagnosticpurposes. The technique has a significant reduction in complexity when comparedto conventional approaches such as the Hough Transform. The reduction in complexitymakes the approach ideal for an embedded vision application suchas the one described in this paper. This paper presents the technique, thetarget embedded architecture and results showing the reduction in complexitywhen compared to a Hough Transform.     

用于光控相控阵雷达的空间光调制器

空间光调制器是光信息处理机的基本结构单元,它能根据电驱动信号或光驱动信号,随时修正与空间和时间有关的读出光束的偏振、相位和幅度.介绍了适用于光控相控阵雷达系统的空间光调制器,包括它们的结构、原理和性能.     

光波分复用技术及其应用

分析了波分复用系统的组成原理和几种分类方式,最后给出了一些基本应用形式。     

激光起爆与点火系统中光纤连接器

介绍了激光起爆与点火系统中光纤连接器的原理、种类、技术特性及损耗，并对激光起爆与点火系统中光纤连接器的研制动向进行了概括，最后得出一些结论。