Optimal distance from high power laser diode to cylindrical microlens in a coupling system

In a practical coupling system, a cylindrical microlens is used to collimate the emission of a high powerlaser diode (LD) in the dimension perpendicular to the junction plane. Using passive alignment, the LD isplaced in the focus of the cylindrical microlens generally, regardless of the performance of the multimodeoptical fiber and the LD. In this paper, a more complete analysis is arrived at by ray-tracing technique,by which the angle θ of the ray after refraction is computed as a function of the angle θo of the ray beforerefraction. The focus of the cylindrical microlens is not always the optimal position of the LD. In fact, inorder to achieve a higher coupling efficiency, the optimal distance from the LD to the cylindrical microlensis dependent on not only the radius R and the index of refraction n of the cylindrical microlens, but alsothe divergence angle of the LD in the dimension perpendicular to the junction plane and the numericalaperture (NA) of the multimode optical fiber. The results of this discussion are in good agreement withexperimental results.

Design of side-pumped Nd : YAG lasers

Design of the typical laser diode side-pumped Nd:YAG rod system has been discussed using the conventional ray tracing method in this paper. Firstly introduce two basic matrices, refractional and translational matrix, described the transmission of nonparaxial light ray in the medium without concerning the absorption of light. And then, using those matrices, analyze the distribution of pump light in the crystal respectively under the condition of directly pumped system and indirectly pumped system with a cylindrical quartz rod as focusing lens. From the result of simulation, we compare the advantage and disadvantage of the two pumped method, and mainly consider how to select the diameter of the focus lens and cooling tube, indicate the effect of deionized water and cooling tube have on the pump light distribution in the active material. At last, make some conclusions about the side-pumped Nd:YAG laser system.

基于空盒自适应生成的动态场景光线跟踪计算

提出了一项光线跟踪新技术,能有效提高光线在空白区域的行进速度.该技术首先用一种新方法创建均匀空间网格,然后用较少的空盒自适应聚集空的空间网格,以加快光线跟踪的计算.新加速结构的创建时间复杂度和空间复杂度均是O(n),而相应的光线跟踪计算的时间复杂度为O(logn),与kd树结构相当.当该结构与已有的一些加速结构结合后,能很好地处理大规模动态场景.比如,光线逐根跟踪且计算二次衍生光线时,新技术可在普通PC机上高真实感地交互绘制包含6G三角面片的多Buddha动态场景.

Droplet Image Feedback Control System in Evaporation Experiment

In order to realize the steady-state droplet evaporation, image feedback control system is designed based on DSP. The system has three main functions: to capture and store droplet images during the experiment; to calculate droplet geometrical and physical parameters such as volume, surface area, surface tension and evaporation velocity at a high-precision level; to keep the droplet volume constant. The DSP can drive an injection controller with the PID control to inject liquid so as to keep the droplet volume constant. The evaporation velocity of droplet can be calculated by measuring the injected volume during the evaporation. The structure of hardware and software of the control system, key processing methods such as contour fitting and experimental results are described.

链霉菌S227抗耐药菌活性成分的研究

本论文以从四川峨嵋山森林土壤中分离筛选获得的一株产抗耐药性活性化合物的链霉菌S227为材料，对发酵液中活性物质的分离纯化及抗耐药性活性进行了研究。 建立了抗耐药性活性的定性、定量检测方法。建立的管蝶法活性定量检测的标准回归方程为：D=4.8229Ln(C)+3.6326 R=0.9972 ；纸片法活性定量检测的标准回归方程为：D=5.5Ln(C)-12.794 R=0.999。 根据建立的样品活性的检测方法，测定了发酵液的初始活性。实验证明活性物质的温度、pH稳定性好。 通过活性的定性、定量追踪方法，分别利用等体积的石油醚、乙酸乙酯、正丁醇在不同的pH梯度下萃取，确定了pH3条件下正丁醇能最大程度的萃取活性物质，说明活性物质极性很大。对正丁醇萃取相经过两次硅胶柱层析及薄层层析分离得到具有抗耐药菌活性的纯化样品S227-4。 经过核磁共振氢谱、碳谱数据分析初步确定S227-4为四聚糖，通过糖的水解实验初步确定S227-4由葡萄糖和半乳糖组成。 纸片法活性检测表明S227-4具有抗耐药菌活性。采用MIC测定法对该样品抗耐药活性进行研究。在证明该样品本身不具有抗菌活性的基础上，以临床分离的耐药性金黄色葡萄球菌为指示菌，考察了该样品与抗生素联合使用时对耐药菌抗生素MIC（最小抑菌浓度）值的影响，结果表明在不影响菌体生长的浓度条件下，该样品能明显降低多株耐药菌对多种抗生素的MIC值，不同程度地恢复所测试耐药菌对相应抗生素的敏感性。如S227-4与青霉素钠联用可以使S. aureus 12352的MIC降低8倍，而与红霉素联用可以使S. aureus 12334的MIC降低128倍。 The purification process and the activity of the anti bacterial drug resistance compounds produced by Streptomyces S227 isolated from the forest soil sample of the Mountain E’MEI in Sichuan Province were studied in this thesis. Quantitative and qualitative activity assay methods of the active compounds were established. The regression equation of the tube method was D=4.8229Ln(C)+3.6326, R=0.9972. The regression equation of the paper method was D=5.5Ln(C)-12.794, R=0.999. According to the established activity assay method, the incipient activity of the broth was evaluated. And it was proved that the stability of the active compounds was good. By quantitative and qualitative activity tracing method, petroleum ether, ethyl acetate and butanol were used to extract the active compounds at different pH. The result showed that butanol was the most effective agent for active component recovery at pH3. From the butanol extraction a purified sample, S227-4, was isolated by silica gel column chromatography and thin-layer chromatography . S227-4 was proved to be a tetra- saccharide by 1H-NMR and 13C-NMR. And its monosaccharides include glucose and galactose by hydrolysate analysis. The anti-drug resistant activity of S227-4 was tested in vitro by MICs assay using different drug resistant Staphylococcus aureus strains isolated clinically. The sample itself showed no anti-microbial activity in growth inhibitory experiment, but when it was used together with different antibiotics, it could remarkably decrease the MICs of different clinically isolated drug-resistant bacterial strains to these antibiotics. For example, when S227-4 was used with penicillin, the MIC of S. aureus 12352 decreased 8 times compared with that when penicillin was used alone. Meanwhile when it was used with erythromycin the MIC of S. aureus 12334 deceased 128 times compared with erythromycin alone.

Conformal irradiation to moving targets in heavy ion radiotherapy with raster-scanning beam delivery system: (II) feasibility experiments

Within the framework of the pilot heavy-ion therapy facility at GSI equipped with an active beam delivery system of advanced raster scanning technique, a feasibility study on actively conformal heavy-ion irradiation to moving tumors has been experimentally conducted. Laterally, real-time corrections to the beam scanning parameters by the raster scanner, leading to an active beam tracing, compensate for the lateral motion of a target volume. Longitudinally, a mechanically driven wedge energy degrader (called depth scanner) is applied to adjust the beam energy so as to locate the high-dose Bragg peak of heavy ion beam to the slice under treatment for the moving target volume. It has been experimentally shown that compensations for lateral target motion by the raster scanner and longitudinal target shift by the depth scanner are feasible.

Dinoflagellate Cysts as Indicators of Cultural Eutrophication in the Oslofjord, Norway

Dinoflagellate cyst records were analysed from four sediment cores from the inner Oslofjord. The cores covered the pre-industrial period, and the most important period of human population growth associated with industrial development of the region, from the mid-1800s to the present, including the reported development of cultural eutrophication. Comparisons between the cyst records and the known history of eutrophication suggest cyst signals that should prove useful for tracing the development of eutrophication. The eutrophication signal consisted of a doubling of total cyst concentration, and a marked increase in one species in particular,Lingulodinium machaerophorum(from <5 to around 50% of the assemblages) with increased eutrophication. In the core considered most representative of general water quality in the inner fjord, these trends reversed back to pre-industrial levels during the 1980s and 1990s when improved sewage treatment took effect.

Dinoflagellate cysts as potential indicators of industrial pollution in a Norwegian Fjord

Variation in dinoflagellate cyst assemblages through the last approximately 300 years was studied in two sediment cores, one from the heavily polluted Frierfjord, and one from the adjoining, relatively unpolluted Brevikfjord, in order to docu1ent possible dinoflagellate responses to pollution. Changes in the cyst-flora were compared with historical information on the development of industry and also with geochemistry of the sediments, reflecting aspects of pollution. In the Frierfjord core, increasing pollution was accompanied by a decrease in cyst concentration, possibly reflecting reduced production, at least of dinoflagellates, and a shift toward more heterotrophic species, possibly reflecting reduced light penetration in the euphotic zone, or increased production of prey for the heterotrophs. These trends seem to have reversed as pollution decreased after about 1975, suggesting that cyst assemblages contain signals that may prove useful for tracing the development of pollution. Cyst assemblages in the Brevikfjord core only showed minor changes.

Fast monostatic GPR modeling

We propose the exploding-reflector method to simulate a monostatic survey with a single simulation. The exploding reflector, used in seismic modeling, is adapted for ground-penetrating radar (GPR) modeling by using the analogy between acoustic and electromagnetic waves. The method can be used with ray tracing to obtain the location of the interfaces and estimate the properties of the medium on the basis of the traveltimes and reflection amplitudes. In particular, these can provide a better estimation of the conductivity and geometrical details. The modeling methodology is complemented with the use of the plane-wave method. The technique is illustrated with GPR data from an excavated tomb of the nineteenth century.

黄土高原竹节形水平沟的断面设计

以陕北延安黄土高原为例 ,经分析得出 :(1)黄土高原在实施竹节水平沟整地工程时 ,设计暴雨可采用 10年一遇 3h降水 6 0 mm的标准 ;(2 )每个竹节的蓄水容积不得小于 2 .5m×1.2 m× 0 .35m

鸡粪中活性有机酸的分离与鉴定

本文通过生物追踪实验法 ,研究了鸡粪中有机酸的生物活性成分 ,并从中筛选出了一种强活性物质 .通过红外光谱和质谱及生源关系初步确定其分子式为C36H56O18Na,名称为 3-O -D -葡萄糖 -6,1 -0 -葡萄糖酸 2 β ,2 ,2 0 -二羟基蛋甾酸钠

基于贝塞尔曲线的WSN等值线绘制算法

从无线传感器网络(WSN)环境数值监测应用的实际需求出发,提出了一种应用于该类场景中的等值线绘制(CMBC)算法.CMBC算法基于图形学中常用的贝塞尔(Bezier)曲线理论,通过选择部分节点提供信息给网关节点绘制等值线.此方法有效解决了监测应用场景中对最终监测精度的需求与大量报告节点所引发的高流量负载和网络能耗之间的矛盾.仿真结果表明,CMBC算法和已有研究工作相比能够使用更少的汇报节点完成高精度等值线的绘制,因此CMBC算法能够节省节点的能量,延长网络的生存期.

散景效果的真实感绘制

针对现有方法绘制的散景效果真实感较差的问题,提出一种基于几何光学理论的散景效果真实感绘制方法.该方法以光线传播的折射定律为基础,利用序列光线追踪方法对相机镜头的光学成像特性进行精确建模;对相机镜头的内部结构进行精确模拟,包括孔径光阑和渐晕光阑,以绘制出由孔径形状和渐晕共同作用的散景效果;利用几何光学理论和序列光线追踪方法精确计算出出射光瞳的位置和大小,以辅助光线采样,提高光线追踪效率.绘制结果表明,利用该方法能够绘制出较为逼真的散景效果,正确模拟了孔径形状和渐晕对散景效果的影响,并具有较高的光线追踪效率.

位置相关数据的模型及关键技术研究

本文介绍了移动计算领域一个较为年轻的新课题——位置相关数据。位置相关数据是一种向移动用户提供即时、即点信息服务的技术。通过位置相关服务用户在移动过程中可以获得与其所在位置相适应的数据信息。 本文首先对位置相关服务的背景问题、关联技术、系统结构等方面作了概要性的介绍。然后从集合和映射的角度出发，探讨了位置相关数据的数学模型。为了使关系数据库能够支持位置相关查询，本文还分析了关系代数的位置相关性，并通过引入位置绑定算子初步建立了位置相关的关系代数。通过对位置绑定策略的讨论，本文提出了两阶段的位置绑定策略，为位置相关查询的优化提供了思路。 为了提高位置绑定的效率，本文进一步研究了位置绑定数据的索引和缓存方法。利用位置相关数据的数据区域的互斥性，本文在~R~树的基础上作了改进并提出了~Contour-R~树索引及其上的相关算法。新索引方法在保持~R~树灵活性的同时避免了~R~在点查询时的回溯，从而能够提高服务器端的查询效率。位置相关数据缓存是减少服务器查询次数的一种技术。本文提出的跨区域语义缓存方法突破了现有基于单一有效区域缓存方法的限制，使得用户可以根据设备的存储能力自行设置有效区域的尺寸。实验表明，在有效区域面积相同的情况下，跨区域缓存比单一有效区域缓存具有更高的命中率。同时，利用本文给出的旋转表示法，对跨区域缓存进行探测只需要通过简单运算即可完成。

基于人脸检测的自动摄像跟踪系统开发研究

自动摄像跟踪系统，是一种通过传感器检测或者数字图像处理的方法，控制摄像机自动的对运动中的人物或特定物体实施跟踪拍摄的系统，融合了计算机网络通信、计算机视觉、传感器网络等多个领域的技术，包含一系列软件和硬件设备，可以广泛运用在安全保卫视频监控，会议摄像，课堂和讲座摄像，表演摄像等场景，是近年来需求增长较大的领域。 人脸检测是数字图像处理和计算机视觉的一个分支问题，指的是在输入的图像中判断是否有人脸存在，并确定出所有人脸的位置、大小甚至姿势朝向的过程，作为进一步控制和处理的依据。这是计算机视觉方向最热门的技术专题之一，拥有非常广阔的应用空间。 目前还没有成熟的自动跟踪摄像系统应用于安全保卫或一般民用摄像领域，已有的一些类似系统也不能完全达到自动跟踪人物摄像的要求，性能距离全自动化无人干涉的跟踪摄像还有相当差距。 本文旨在运用计算机网络作为图像数据和控制信息媒体，运用数字图像处理领域计算机视觉中人脸检测和人脸跟踪的技术作为自动人物识别的依据，设计人物检测、人物跟踪、摄像机自动跟踪拍摄、人物位置运动估算、简单运动估计等算法策略，研究和开发一套完整的自动摄像跟踪系统软件，支持网络远程访问和控制，在无需人为操作和调整的情况下，实现对人物脸部自动跟踪拍摄的功能。这个系统适用于一般需求的安保视频监控和课堂自动摄像的应用。 本系统相对于已有的性能较好的类似系统——红外视频监控系统有许多明显优势，在达到很好的智能化、实时性、响应速度和准确性的同时，实现了设备的简化，大大降低了成本；同时在现场部署时不需要重新配置，后期维护简便；并且能够实现连续位置跟踪；系统稳定性优良等等。