三维航标监测与管理系统的设计与实现

设计了三维航标监测与管理系统的整体框架和功能结构,研究了其涉及的若干关键技术,开发实现了系统功能.     

The Morávka meteorite fall: 3. Meteoroid initial size,history, structure,and composition

Abstract— The properties and history of the parent meteoroid of the Morávka H5–6 ordinary chondrites have been studied by a combination of various methods. The pre‐atmospheric mass of the meteoroid was computed from fireball radiation, infrasound, seismic signal, and the content of noble gases in the meteorites. All methods gave consistent results. The best estimate of the pre‐atmospheric mass is 1500 ± 500 kg. The fireball integral bolometric luminous efficiency was 9%, and the acoustic efficiency was 0.14%. The meteoroid cosmic ray exposure age was determined to be (6.7 ± 1.0) × 10⁶ yr. The meteorite shows a clear deficit of helium, both ³He and ⁴He. This deficit can be explained by solar heating. Numerical backward integration of the meteoroid orbit (determined in a previous paper from video records of the fireball) shows that the perihelion distance was probably lower than 0.5 AU and possibly as low as 0.1 AU 5 Ma ago. The collision which excavated Morávka probably occurred while the parent body was on a near‐Earth orbit, as opposed to being confined entirely to the main asteroid belt. An overview of meteorite macroscopic properties, petrology, mineralogy, and chemical composition is given. The meteorites show all mineralogical features of H chondrites. The shock level is S2. Minor deviations from other H chondrites in abundances of trace elements La, Ce, Cs, and Rb were found. The ablation crust is enriched with siderophile elements.     

基于Erdas2013的Pleiades卫星影像区域网平差设计与实现

介绍了Pleiades卫星影像数据及基于Erdas 2013的Pleiades卫星影像应用的可行性和区域网平差技术,为该卫星影像应用于相关测绘工程提供了技术依据。     

Habitat suitability curves for benthic macroinvertebrates from a small New Zealand river

We developed habitat suitability curves (HSC) using generalised additive models (GAMs) for nine benthic macroinvertebrate taxa from a small New Zealand river for hydraulic-habitat modelling assessments of instream flow requirements. We included interaction terms between the primary variables (water depth, velocity, substrate) when significant, to address a longstanding criticism of univariate HSC. To date, only large-river univariate HSC have been available and these have been used in hydraulic-habitat applications on small rivers, despite doubt over the transferability of HSC between rivers of different size and type. We tested the outcome on the predicted abundance–flow relationship of applying the small-river habitat suitability GAMs versus large-river GAMs for two taxa on the same small river. We found the effects of flow allocation were overestimated by the large-river GAMs relative to the small-river GAMs. Further research to develop general HSC for categories of river size and type is needed to better inform hydraulic-habitat modelling applications.     

基于Wallis滤波器的异源遥感影像匀光方法

针对异源遥感影像由于辐射水平差异导致地物在相邻图像上亮度值存在差异的现象,分析了造成影像间色调差异的各种原因以及现有处理方法在进行影像间色彩平衡处理时存在的问题,实现了基于Wallis滤波器进行匀光的相关算法,并通过多组匀光实验取得了较好的色彩平衡效果。     

藏西北革吉县雄巴乡场镇冻土灾害特征及防治措施

近年来,藏西北革吉县雄巴乡场镇内的冻土灾害日趋严重,研究该区冻土灾害的特征、成因及危害,对制定相应的防灾减灾政策具有重要意义.从基本特征、成因条件、风险性及防治措施等方面对雄巴乡场镇的冻土灾害开展了综合研究,认为加剧该区冻土灾害的主要原因是全球气候变暖导致的降雨量增加和气温升高,使场镇内透水性差、不均匀分布的土体含水率...     

Chemo- and Biostratigraphy of the Jurassic Oil Shales from the Qiangtang Basin, Northern Tibet, China: A Case Study of the Toarcian Oceanic Anoxic Event

The marine oil shales of the Qiangtang Basin, northern Tibet, exposed in the Biluo Co, Tuonamu, Shenglihe and Changsheshan areas are believed to be important petroleum source rocks. This work comprehensively analyzed the carbon isotopes, trace elements, and calcareous nannofosills, ammonites and bivalves of the Biluo Co section in the Qiangtang Basin. The organic carbon isotopes show a positive excursion close to 2.17‰(relative to PDB), which, albeit significantly smaller, may also be associated with other Early Toarcian Oceanic Anoxic Events(T-OAE) in the European epicontinental seas and the Tethyan continental margins. Coinciding with the Early Toarcian transgression, the oxygen deficiency in bottom water had led to dysoxic-anoxic conditions and deposition of black shales lacking benthic fauna. Under such condition, the redox-sensitive trace metals such as Mo, V, Ni, Cr, and U were enriched, in conjunction with high planktonic productivity of Watznaueriaceae calcareous nannofossils. Comparison of the results with the records of chemo-and biostratigraphy, as well as the palaeogeography during the Early Jurassic suggests that the anoxia linked to the Early Toarcian oceanic anoxic event was mainly caused by the high surface water temperature, sea-level rise and an increase of surface water productivity.     

Facies and palaeosol analysis in a progradational distributive fluvial system from the Campanian–Maastrichtian Bauru Group,Brazil

The Upper Cretaceous Bauru Group in south‐east Brazil consists of alluvial strata whose characteristics and distribution indicate a fluvial system developed in a semi‐arid to arid climate. Sections exposed within a 90 000 km² study area in Minas Gerais State (in south‐eastern Brazil) were evaluated using facies and palaeosol analysis to formulate depositional and pedogenic models that may account for geomorphic and climate features. From east to west, the study succession records a gradual decrease in grain size, an increase in the width/thickness ratio in channels, a decrease in the lateral and vertical connectivity of channel deposits, and an increase in overbank deposits. The fluvial architecture indicates a braided channel belt, ephemeral ribbon–channels, and an unconfined fluvial facies from east to west in the study area. The lateral and vertical distribution of facies, stratigraphic architecture and palaeocurrent data suggest proximal, medial and distal portions of a progradational distributive fluvial system. The sedimentary dynamics were marked by the building and abandonment of channels related to processes of aggradation, vegetation growth and palaeosol generation. Macromorphological and micromorphological analyses have identified pedological and mineralogical features that indicate an arid to semi‐arid climate with a provenance from the north‐eastern part of the basin (Alto Paranaiba Uplift). From the proximal to the distal portions of the distributive fluvial system, the palaeosol development is different. In the proximal portion, the palaeosols are absent or poorly developed, allowing a possible general comparison with the present soil order: Inceptisols and Aridisols. In the medial portion of the fluvial system, the palaeosols are well‐developed and characterized by Bt, Btk, C and Ck horizons (Alfisols, Aridisols, Inceptisols and Entisols). Poorly drained to well‐drained palaeosols from the base to the top in the distal plain (Aridisols and Inceptisols) are associated with geomorphic and hydromorphic changes in the fluvial system due to progradational evolution. The genetic relationship between the fluvial architecture and the palaeosols enhances the understanding that the sedimentation and pedogenesis that occurs in different portions of the distributive fluvial system are related to the tectonic and climatic evolution of the basin.     

兰州城区稳定能量及其与空气污染的关系

从能量学的观点出发，提出了描述地面至特定高度大气层结构稳定度的参数－稳定能量，并给出了具体计算方法。根据1988－1992年兰州气象站逐日08：00（北京时，下同）的探空资料，计算了300－1000m每隔50m共15层的稳定能量。利用同期兰州市环境监测站自动监测系统监测的兰州城区3种主要空气污染物二氧化硫、一氧化碳和氮氧化物（SO2、CO、NOX）的日平均浓度资料，计算了地面气象要素、低空气象参数、低空风和稳定能量等气象因子与SO2、CO、NOX之间的相关。结果表明：（1）用稳定能量来描述低层大气的稳定性更为合理一些；（2）在诸多气象因子中，稳定能量与SO2、CO、NOX浓度之间的相关性最显著；（3）稳定能量的年变化规律与空气污染浓度的年变化规律基本一致；（4）逐月看，各层稳定能量与SO2浓度之间均为正相关，除7月份以外，大多数层次均通过了α＝0．01显著性水平的相关性检验。