硼酸铝钕(NAB)晶体光学均匀性的测量

NAB晶体是一种综合性能较好的新型激光工作物质,有希望做成高效的小型固体激光器。本文介绍一种测量这种晶体光学均匀性的方法。 一般都采用在干涉仪上观测干涉图样来判定激光棒的光学均匀性。NAB晶体的吸收光谱曲线显示出其在可见光光谱区内有多个吸收峰。我们注意到:通常用做激光干涉仪光源的He-Ne激光器发射的632.8nm谱线正位于NAB晶体的一个吸收峰,并用输出约为45mW     

光孤子相互作用对压缩态的影响

在线性近似条件下，量子化了非线性薛定谔方程，用后向传播法数值求解了光孤子相互作用对压缩比的影响。数值结果表明，在碰撞距离附近，压缩比显著增加。     

纸张背衬不同衬底时的光反射率的研究

从理论上研究了纸张背衬不同衬底的光反射率，得出下列表达式：Ｒｂ＝Ｒｏ＋（Ｒ∞－Ｒｏ）×（１／Ｒ∞－Ｒｏ）／（１／Ｂ－Ｒｏ）（Ｂ为衬底的光反射率），该式简单实用且物理意义明确。利用上述公式，可将Ｔａｐｐｉ标准列出的Ｔａｐｐｉ不透明度Ｃ０．８９的换算公式简化，并可从理论上定性地讨论纸张不透明度与印刷透印性的关系。     

Si_（1－x）Ge_x／Si定向耦合器的研制

在运用ＳｉＧｅ脊形波导单模条件和有效折射率法分析ＳｉＧｅ／Ｓｉ定向耦合器结构参数的基础上，采用分子束外延和各向异性腐蚀技术制备出Ｓｉ１－ｘＧｅｘ／Ｓｉ（ｘ＝０．０５）单模定向耦合器．在波长为１．３μｍ时，平均串音小于－１８．１ｄＢ，输出功率耦合效率达到９８．１％     

电磁波在包含各向异性媒质多层介质中传播的分析

对电磁波在包含各向异性媒质多层介质中的传播进行分析，给出了闭合形式的解，该结构可用作法拉第旋转器，与其它准光元件组合构成的准光环行器或隔离器。也可用作辐射口径，通过改变磁化场方向和强度实现波束扫描或极化变化，给出了法拉第旋转角计算结果和实验结果。     

G.652光纤上的2.5Gbit／s色散受限系统

本文根据色散受限中继段长度的计算，对实际工程中１５５０ｎｍ波长２．５Ｇｂｉｔ／ｓ系统进行计算比较得出啁啾声引起的色散不容忽视，它使２．５Ｇｂｉｔ／ｓ成为色散受限系统。对１３１０ｎｍ波长６２２Ｍｂｉｔ／ｓ系统，当使用多纵模激光器时，往往也会成为色散受限系统。     

Transmission Fiber Chromatic Dispersion Dependence on Temperature: Implications on 40 Gb/s Performance

In this letter, we will evaluate the performance degradation of a 40 km high‐speed (40 Gb/s) optical system, induced by optical fiber variations of the chromatic dispersion induced by temperature changes. The chromatic dispersion temperature sensitivity will be estimated based on the signal quality parameters.     

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.     

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.