72 resultados para Tracing


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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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

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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.

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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。

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The dewetting behavior of polystyrene (PS) film on poly(methyl methacrylate) (PMMA) sublayer was investigated by changing the short-range roughness of the PMMA sublayer systemically. When the bilayer film was heated to the temperature above both Tgs, the protuberances formed in both layers to reduce the system energy. By tracing the dewetting process of the PS up-layer, the dewetting velocity was found to increase with the roughness of the sublayer.

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Rare earth elements (REEs) of 91 fine-grained bottom sediment samples from five major rivers in Korea (the Han, Keum, and Yeongsan) and China (the Changjiang and Huanghe) were studied to investigate their potential as source indicator for Yellow Sea shelf sediments, this being the first synthetic report on REE trends for bottom sediments of these rivers. The results show distinct differences in REE contents and their upper continental crust (UCC)-normalized patterns: compared to heavy rare earth elements (HREEs), light rare earth elements (LREEs) are highly enriched in Korean river sediments, in contrast to Chinese river sediments that have a characteristic positive Eu anomaly. This phenomenon is observed also in primary source rocks within the river catchments. This suggests that source rock composition is the primary control on the REE signatures of these river sediments, due largely to variations in the levels of chlorite and monazite, which are more abundant in Korean bottom river sediments. Systematic variations in I LREE pound/I HREE pound ratios, and in (La/Yb)-(Gd/Yb)(UCC) but also (La/Lu)-(La/Y)(UCC) and (La/Y)-(Gd/Lu)(UCC) relations have the greatest discriminatory power. These findings are consistent with, but considerably expand on the limited datasets available to date for suspended sediments. Evidently, the REE fingerprints of these river sediments can serve as a useful diagnostic tool for tracing the provenance of sediments in the Yellow Sea, and for reconstructing their dispersal patterns and the circulation system of the modern shelf, as well as the paleoenvironmental record of this and adjoining marginal seas.

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The onshore-offshore deep seismic experiment was carried out for the first time and filled the blankness of the seismic surveys in the transition area between South China and northeastern South China Sea. The seismic data were analyzed and processed. The different seismic phases were identified and their travel time arrivals were modeled by ray-tracing to study the P-wave velocity crustal structure of this area. The crustal structure of this area is the continental crust. The crust thickness is gradually decreasing southward along the on-shore-offshore seismic line. The low-velocity layer (5.5 similar to 5.9 km (.) s(-1)) exists generally in the middle crust (about 10.0 similar to 18.0km)with about 2.5 similar to 4.0 km thickness, which is also thinning seaward. No obvious high-velocity layer appears in the lower crust. The Binhai (littoral) fault zone is a low velocity zone, which is located about 35km southeast to the Nan'ao station and corresponding to the gradient belt of gravity & magnetism anomalies. The depth of the fault zone is close to the Moho discontinuity. The littoral fault zone is a boundary between the normal continental crust of South China and the thinned continental crust of the sea area.

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With the intermediate-complexity Zebiak-Cane model, we investigate the 'spring predictability barrier' (SPB) problem for El Nino events by tracing the evolution of conditional nonlinear optimal perturbation (CNOP), where CNOP is superimposed on the El Nino events and acts as the initial error with the biggest negative effect on the El Nino prediction. We show that the evolution of CNOP-type errors has obvious seasonal dependence and yields a significant SPB, with the most severe occurring in predictions made before the boreal spring in the growth phase of El Nino. The CNOP-type errors can be classified into two types: one possessing a sea-surface-temperature anomaly pattern with negative anomalies in the equatorial central-western Pacific, positive anomalies in the equatorial eastern Pacific, and a thermocline depth anomaly pattern with positive anomalies along the Equator, and another with patterns almost opposite to those of the former type. In predictions through the spring in the growth phase of El Nino, the initial error with the worst effect on the prediction tends to be the latter type of CNOP error, whereas in predictions through the spring in the decaying phase, the initial error with the biggest negative effect on the prediction is inclined to be the former type of CNOP error. Although the linear singular vector (LSV)-type errors also have patterns similar to the CNOP-type errors, they cover a more localized area than the CNOP-type errors and cause a much smaller prediction error, yielding a less significant SPB. Random errors in the initial conditions are also superimposed on El Nino events to investigate the SPB. We find that, whenever the predictions start, the random errors neither exhibit an obvious season-dependent evolution nor yield a large prediction error, and thus may not be responsible for the SPB phenomenon for El Nino events. These results suggest that the occurrence of the SPB is closely related to particular initial error patterns. The two kinds of CNOP-type error are most likely to cause a significant SPB. They have opposite signs and, consequently, opposite growth behaviours, a result which may demonstrate two dynamical mechanisms of error growth related to SPB: in one case, the errors grow in a manner similar to El Nino; in the other, the errors develop with a tendency opposite to El Nino. The two types of CNOP error may be most likely to provide the information regarding the 'sensitive area' of El Nino-Southern Oscillation (ENSO) predictions. If these types of initial error exist in realistic ENSO predictions and if a target method or a data assimilation approach can filter them, the ENSO forecast skill may be improved. Copyright (C) 2009 Royal Meteorological Society

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High-resolution sampling, measurements of organic carbon contents and C-14 signatures of selected four soil profiles in the Haibei Station situated on the northeast Tibetan Plateau, and application of C-14 tracing technology were conducted in an attempt to investigate the turnover times of soil organic carbon and the soil-CO2 flux in the alpine meadow ecosystem. The results show that the organic carbon stored in the soils varies from 22.12x10(4) kg C hm(-2) to 30.75x10(4) kg C hm(-2) in the alpine meadow ecosystems, with an average of 26.86x10(4) kg C hm(-2). Turnover times of organic carbon pools increase with depth from 45 a to 73 a in the surface soil horizon to hundreds of years or millennia or even longer at the deep soil horizons in the alpine meadow ecosystems. The soil-CO2 flux ranges from 103.24 g C m(-2) a(-1) to 254.93 gC m(-2) a(-1), with an average of 191.23 g C m(-2) a(-1). The CO2 efflux produced from microbial decomposition of organic matter varies from 73.3 g C m(-2) a(-1) to 181 g C m(-2) a(-1). More than 30% of total soil organic carbon resides in the active carbon pool and 72.8%. 81.23% of total CO2 emitted from organic matter decomposition results from the topsoil horizon (from 0 cm to 10 cm) for the Kobresia meadow. Responding to global warming, the storage, volume of flow and fate of the soil organic carbon in the alpine meadow ecosystem of the Tibetan Plateau will be changed, which needs further research.