杭州主城区O3与前体物浓度变化特征

利用2004～2006年杭州主城区环境空气监测资料,研究了O_3、NO_2和CO浓度的分布特征和时间变化规律,结果表明,杭州主城区3年的O_3、NO_2、CO的年均浓度都不大,分别为40、60、1400μg·m~(-3).四季中O_3、NO_2和CO浓度相差较大,O_3是夏季高冬季低,NO_2和CO则是秋季较高,夏季较低.O_3、NO_2和CO浓度日变化也很明显,其中O_3是单峰形态,NO_2和CO为双峰形态.不同天气条件下O_3与烃类的关系研究表明,晴天时烃类浓度减少,O_3浓度明显增加;阴天时O_3浓度较低,烃类浓度较高,它们的变化不大.白天和夜晚不同风速时O_3、C_2-C_(12)的浓度变化不同,白天风速增大时C_2-C_(12)浓度减小,O_3浓度增加;晚上无此变化.     

Recurrence of major flank landslides during the last 2-Ma-history of Reunion Island

New detailed swath bathymetry and backscatter data corroborate the existence of four large bulges on the submarine flanks of Reunion Island. These fan-shaped promontories are 20–25 km wide at the coastline and 70–150 km across the seafloor 40–50 km offshore. Their surfaces are characterized by a speckle sonar pattern, indicating the presence of large blocks up to several hundred meters across. Each bulge results from the superposition of multiple landslide deposits whose older ones are dissected and delimited by erosive channels as much as 200 m deep and 20 km long. The submarine flanks of Reunion Island are thus mostly built by accumulation of debris avalanche fans. Morphologic and geologic evidence define large subaerial source areas for these mass-wasting events. In particular, inferred headwalls of most landslides having affected the Piton des Neiges massif generally coincide with the boundaries of its cirques (Mafate, Salazie, and Cilaos), whereas recurrent landslides have resulted in the formation of large concentric amphitheatre structures through the Piton de la Fournaise massif. Thus, about 15 slide events accompanied growth of the Reunion Island shield since 2 Ma.Editorial responsibility: J. Stix     

地质样品中稀土总量的X射线荧光分析法测定

本文研究了稀土元素Ｃｅ的质量分数ｗＣｅ与由Ｃｅ至Ｌｕ１２元素质量分数之和ｗ１２（Ｎｄ除外）间的关系，发现ｗＣｅ和ｗ１２间存在明显一致的线性相关性。回归ｗ１２－ＩＣｅ标准工作曲线，实现了ｗ１２的直接测定。方法采用直接粉末压片制样，光谱仪测定ｗＣｅ，ｗＬａ，ｗＮｄ，ｗＹ，ｗ１２参数条件实现与稀土总量的转换。按本法对标准物质进行单项测定，结果令人满意     

Teaching Spatial Thinking and Geospatial Technologies Through Citizen Mapping and Problem-Based Inquiry in Grades 7-12

Our project introduced students in grades 7 through 12 to spatial thinking and geospatial technologies in the context of challenges in their community. We used a mix of levels of inquiry to advance learning from teacher- to student-guided through a citizen mapping group activity. Student-suggested problem-based topics included parks and community gardens, crime, housing, and youth employment opportunities. Qualitative methods were used to evaluate students’ knowledge of spatial thinking and geospatial technologies, including map interpretation, a case study, daily exit slips, and interviews. Overall, the students’ awareness of their community, spatial thinking, and geospatial technologies increased as a result of participation.     

控制点布设对冰川区无人机摄影测量精度的影响

冰川监测是冰冻圈科学研究中的一项重要基础内容,获取高质量冰川DEM和DOM数据是研究的基础。随着无人机技术的兴起,给冰川监测提供了全新的技术手段,然而冰川区开展无人机摄影测量时,地面控制点的布设与测量成为能否获取高精度数据产品的关键,而山地冰川往往伴随着地形复杂,行走困难,野外实地测量难以全面实施等不利因素。本研究中以位于祁连山西段大雪山地区的老虎沟12号冰川末端部分为研究区域,设计实施了多种控制点布设方案,使用低空微型无人机飞行3个架次,获取研究区航摄影像。通过对比控制点在不同分布情况及数量情况下,DEM和DOM数据检查点的精度,评价不同控制点布设方案的可行性。对比结果显示,在航飞过程中使用单格网模式即可获取高精度的影像数据;实施地面控制作业时,使用5—7个控制点均匀分布在测量区即可获取较高精度的图像数据;当冰川区不能满足均匀布设控制点时,可沿冰川主流线布设足够数量的控制点,所得图像精度也可以满足冰川学研究要求;若只能在冰川中下部或者中上部布设控制点,则控制点应覆盖冰面起伏较大的区域。     

日本绒螫蟹放流群体12S rRNA序列研究

参考果蝇与蚤状溞序列进行了日本绒螯蟹放流群体的线粒体DNA 12S rRNA基因片段的引物设计、PCR扩增及序列测定,得到457bp的碱基序列,其A、T、G、C含量分别为158bp(34.57%)、178bp(38.95%)、51bp(11.16%),70bp(15.32%),与果蝇与蚤状相同基因片段序列含量相似.     

都江堰震后土地利用/覆被变化信息提取方法研究

快速和精确评估"5·12"汶川地震后的土地利用/覆被变化对科学减灾、灾后重建及生态环境恢复具有重要意义。常规方法从遥感图像上提取土地利用/覆被变化信息时,多以研究区整体为处理对象,直接对全图像进行分类提取,容易忽略地形地貌和地质构造等背景因素对分类结果的影响。本文以都江堰为试验区,根据地质构造展布特征及地形地貌发育形态将其分成平原区(Ⅰ区)、低山区(Ⅱ区)、中高山区(Ⅲ区)和高山区(Ⅳ区)。对Ⅰ区采用ISODATA方法进行非监督分类;对Ⅱ区和Ⅲ区分别采用最大似然(ML)分类法进行监督分类;对Ⅳ区采用人机交互解译方法进行分类。试验结果表明,基于地理地质环境的分块分类方法是高效、精确的。     

A mathematical and numerical model for reactive fluid flow systems

We formulate mathematical and numerical models for multispecies, multi-phase and non-isothermal reactive fluid flow in porous media focusing on the chemical reactions and the transport of solutes. Mass conservation and stability in the time integration are emphasized. We use cell-centered finite volume differencing in space and an implicit Runge-Kutta method in time. Assuming two space dimensions, we introduce flux approximation for arbitrarily shaped convex quadrilaterals. On equidistant and variable sized rectangular grids we choose limited κ= related schemes to approximate the advective flux and the central difference scheme for the diffusive flux. On non-rectangular grids we recommend the VF9 scheme for the estimation of the diffusive flux. Our model exists as a code. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ammonia observations of the nearby molecular cloud MBM 12

We present NH₃(1,1) and (2,2) observations of MBM 12, the closest known molecular cloud (65-pc distance), aimed at finding evidence for on-going star formation processes. No local temperature (with a T _rot upper limit of 12 K) or linewidth enhancement is found, which suggests that the area of the cloud that we have mapped (15-arcmin size) is not currently forming stars. Therefore this nearby 'starless' molecular gas region is an ideal laboratory to study the physical conditions preceding new star formation.
A radio continuum source has been found in Very Large Array archive data, close to but outside the NH₃ emission. This source is likely to be a background object.