天津港虚拟现实仿真系统的研究与实现     

周世波  熊振南 《测绘科学》2012,(4):178-180

为增强海事管理人员对监管水域的感性认识,提高监管水平,本文提出了虚拟天津港通航环境构建流程,采用虚拟现实技术、GIS技术、数据库技术等实现了虚拟现实仿真系统,并从减少三角形数量、调整数据库结构2个方面提出了大规模数据优化处理的方法;利用Vega中的粒子系统对雨雪等自然现象进行了仿真。实际应用表明,该系统可以为天津港通航安全的监管提供辅助支持。  相似文献   

城市公交换乘服务设计与实现     

曹建成  刘继生  刘建涛 《测绘与空间地理信息》2012,(7):70-73

以地理信息公共服务平台的公众服务为出发点,针对公众出行的实际问题,设计了以纯关系结构表达并兼顾图形表达的公交数据模型,在此基础上实现了以换乘次数最少为主要目标的公交换乘算法,并封装形成基于OGC服务接口规范的公交换乘服务,通过公共服务平台提供服务。  相似文献   

基于变化轨迹探测的植被景观格局动态分析——以塔里木河下游生态输水区域为例   总被引：2，自引：0，他引：2  

刘桂林  艾里西尔·库尔班  玉米提·哈力克  段含明  Philipp Gartner  阿布都米吉提·阿布利克木  牛婷 《中国沙漠》2012,32(5):1472-1478

 在遥感与GIS技术支持下,以2006、2007、2009、2010年Landsat-5/TM影像与2008年的CBERS/CCD影像为主要数据源,获得5 a的植被/非植被类型图。在此基础上,提取并归纳5 a间的植被变化轨迹:恒定植被、恒定非植被、转变为植被、转变为非植被、非稳定变化。利用景观格局分析软件FRAGSTATS 3.3计算了变化轨迹景观格局的3种景观指标。结果表明,2006—2010年植被面积减小,主要因为生态输水量减小、输水间隔较大,导致草本植被、乔灌木幼苗死亡;恒定非植被的比重最大,表明非植被类型是研究区的基质,其次是转变为非植被的比重,说明5 a间植被的衰退程度要强于恢复程度;转变为植被与非稳定变化两种类型属于过渡性植被变化类型,受生态输水量、分布的制约严重;各种变化轨迹类型的形状规则较为稳定,其中以恒定非植被类型最稳定而非稳定变化类型最不稳定。  相似文献   

兰州春季沙尘过程PM₁₀输送路径及其潜在源区   总被引：4，自引：0，他引：4  

刘娜  余晔  陈晋北  何建军  赵素平 《大气科学学报》2012,35(4):477-486

将2001-2008年分为沙尘天气相对多年和相对少年,计算兰州市春季逐日4个时次的4 d气团后向轨迹。通过聚类分析得到春季到达兰州市区的主要气团轨迹组,结合可吸入颗粒物PM₁₀日均质量浓度资料,通过计算潜在源贡献因子PSCF(potential source contribution function)和浓度权重轨迹CWT(concentration-weighted trajectory),得到影响兰州市春季PM₁₀质量浓度的潜在源区以及不同源区对兰州市春季PM₁₀质量浓度贡献的差异。结果表明,在沙尘天气相对多年,西路径和西北路径发生比例最高,分别占总轨迹的33%和19.4%,其中有50%以上为污染轨迹,是造成兰州市春季高质量浓度PM₁₀污染的主要输送路径。沙尘天气相对少年的主要输送路径是西路径,其次是北路径,分别占23.6%和18%。影响兰州市春季大气PM₁₀质量浓度的潜在源区分布在新疆塔里木盆地、吐鲁番盆地、青海柴达木盆地、甘肃河西走廊、内蒙古中部和西部的沙漠戈壁地区。  相似文献   

Study of the insulation effect of freezing apparatuses     

JingWu Huang  JianPing Wang  Heng Wang 《寒旱区科学》2012,4(1):0028-0033

In-situ tests and numerical manipulations were conducted for comparison of superior/inferior quality of casing-tube-vacuumized insulation and polyurethane insulation of freezing apparatuses in relation to non-uniform cold distribution in the multi-coil freezing layout and the contradiction between large-coil diameter layout of the freezing holes and stability of the headframe base. Tests show that: (1) under current technology, vacuumized insulation is of short duration due to lack of appropriate applied vacuum; (2) after the freezing pipe is insulated with polyurethane, the temperature gradient is less than no insulation, and the temperature difference between insulated and non-insulated apparatuses is stable as the freezing period increases. Finally, it is pointed out that polyurethane insulation is quite efficient in present technical freezing construction.  相似文献   

Geology and geochemistry of the Mammoth breccia pipe,Copper Creek mining district,southeastern Arizona: evidence for a magmatic–hydrothermal origin     

Eric D. Anderson  William W. AtkinsonJr.  Timothy Marsh  Alexander Iriondo 《Mineralium Deposita》2009,44(2):151-170

The Copper Creek mining district, southeastern Arizona, contains more than 500 mineralized breccia pipes, buried porphyry-style, copper-bearing stockworks, and distal lead–silver veins. The breccia pipes are hosted by the Copper Creek Granodiorite and the Glory Hole volcanic rocks. The unexposed Mammoth breccia pipe, solely recognized by drilling, has a vertical extent of 800 m and a maximum width of 180 m. The pipe consists of angular clasts of granodiorite cemented by quartz, chalcopyrite, bornite, anhydrite, and calcite. Biotite ⁴⁰Ar/³⁹Ar dates suggest a minimum age of 61.5 ± 0.7 Ma for the host Copper Creek Granodiorite and ⁴⁰Ar/³⁹Ar dates on hydrothermal sericite indicate an age of 61.0 ± 0.5 Ma for copper mineralization. Fluid inclusion studies suggest that a supercritical fluid with a salinity of approximately 10 wt.% NaCl equiv. condensed to a dilute aqueous vapor (1–2.8 wt.% NaCl equiv.) and a hypersaline brine (33.4–35.1 wt.% NaCl equiv.). Minimum trapping temperatures are 375°C and trapping depths are estimated at 2 km. Sulfur isotope fractionation of cogenetic anhydrite and chalcopyrite yields a temperature of mineralization of 469 ± 25°C. Calculated oxygen and hydrogen isotope values for fluids in equilibrium with quartz and sericite range from 10.2‰ to 13.4‰ and −60‰ to −39‰, respectively, suggesting that the mineralizing fluid was dominantly magmatic. Evidence from the stable isotope and fluid inclusion analyses suggests that the fluids responsible for Cu mineralization within the Mammoth breccia pipe exsolved from a gray porphyry phase found at the base of the breccia pipe.  相似文献   

The future of containerization: perspectives from maritime and inland freight distribution     

Theo Notteboom  Jean-Paul Rodrigue 《GeoJournal》2009,74(1):7-22

As containerization enters its peak growth years, its potential future developments over maritime and inland freight transport systems are being questioned. A series of issues can either further accelerate the adoption of containerization worldwide or, alternatively, could impose an upper limit to the extraordinary contribution that containers have implied for logistics systems and global commodity chains. These mainly include macro-economic, technical/operational and governance factors. Future containerization will be largely determined by interactions within and between four domains ranging from a functional to a spatial perspective. The logistical domain involves the functional organization of transport chains and their integration in supply chains. The transport domain involves the operation of transport services and intermodal operations. The infrastructural domain involves the provision and management of basic infrastructure for both links and nodes in the transport system. The locational domain relates to the geographical location of nodes and sites in the economic space and forms a basic element for their intrinsic accessibility in terms of centrality or intermediacy. It is underlined that the future of containerization will dominantly be shaped by inland transport systems.  相似文献   

拉曼光谱方法测量流体包裹体的内压及其应用   总被引：2，自引：0，他引：2       下载免费PDF全文

郑海飞  乔二伟  杨玉萍  段体玉 《地学前缘》2009,16(1):1

通过金刚石压腔和显微激光拉曼光谱方法,获得了流体包裹体中H2O-NaCl体系的O—H、碳酸根的C—O、硫酸根的S—O和正庚烷-环己烷的C—H振动拉曼位移与温度和压力关系的表达式。该研究结果可以用于实测流体包裹体在不同温度下的内压,并可由此获得流体包裹体的p-t线或等容线。这不仅有助于精确获得流体包裹体的形成温度和形成压力,也可为研究和确定流体包裹体中流体的组成和性质提供依据。  相似文献   

汕头第二过海水管工程顶管穿越障碍物技术   总被引：3，自引：0，他引：3  

钟俊彬  王作民  曹玉萍 《岩土工程技术》2009,23(6):321-323

汕头第二过海水管工程中钢管顶管一次顶进长度2080m,是目前世界上一次顶进长度最长的钢顶管工程。该顶管成功地穿越不稳定的块石结构海堤和海底中风化花岗岩层两大障碍物,标志着顶管设计、施工技术的重大突破,拓展了顶管施工方式的应用范围。  相似文献   

柴达木盆地资源环境科学钻探工程实践与认识          下载免费PDF全文

任维焕 《探矿工程》2009,36(6):1-5

为应对柴达木盆地资源环境科学钻探工程项目施工地区岩层中固结程度松软、碎脆、富水、易变形、怕冲刷及易溶蚀等特点,钻进中不易采取岩矿心,钻进粘土及淤泥时缩径严重,孔壁不稳定及地层内广泛分布着层间高承压卤水和天然气,极易发生涌水或井喷的问题,机械岩心深孔钻进施工中合理解决岩心采取率低,护孔压井防喷。是确保科学钻探工程顺利实施的关键点。本项目采用专为资源环境科学钻探设计的隔水单动三重管取心钻具。常规钻杆取心;适宜的钻进方法;借鉴石油钻井泥浆压喷护壁工艺和压喷设施及措施。保证了环境科学钻探工程的施工要求和实验要求。  相似文献