中国面向遥感应用的垂直起降无人机现状和 应用前景分析     

杨梦琳  李道春  万志强  严德  王耀坤 《地球信息科学学报》2019,21(4):496-503

近年来,针对中国生态环境、洪涝灾害应急响应、国土安全监测等遥感观测任务,无人航空遥感手段需求越来越多。构建异构无人航空器遥感观测多任务集群系统是近几年的发展目标,为完成无人航空遥感生态建设,垂直起降无人机以其不受场地限制起降又可快速巡飞的特点,在多个领域发挥着越来越大的作用。本文主要研究内容包括国内垂直起降无人机发展现状调研、面向航空遥感应用市场的无人机分析及典型机型介绍、垂直起降无人机在遥感领域的应用场景及案例分析、垂直起降无人机在遥感领域的应用前景及发展趋势等。通过广泛调研及深入分析可知,目前垂直起降固定翼无人机正逐步取代多旋翼飞行器的主导地位;垂直起降无人机占据了遥感应用无人机80.47%的市场份额;动力多元化、系统智能化、布局多样化、尺寸小型化等是面向遥感应用的垂直起降无人机的发展方向。本文较为全面地阐述和剖析了面向遥感应用的垂直起降无人机的相关内容,为遥感航空无人机生态建设提供了参考与支撑。  相似文献   

The CM carbonaceous chondrite regolith Diepenveen     

Marco Langbroek  Peter Jenniskens  Leo M. Kriegsman  Henk Nieuwenhuis  Niek De Kort  Jacob Kuiper  Wim Van Westrenen  Michael E. Zolensky  Karen Ziegler  Qing‐Zhu Yin  Matthew E. Sanborn  Josh Wimpenny  Akane Yamakawa  Sebastiaan J. De Vet  Matthias M. M. Meier  Kees C. Welten  Kunihiko Nishiizumi  Marc W. Caffee  Aaron S. Burton  Jason P. Dworkin  Daniel P. Glavin  Qinghao Wu  Richard N. Zare  Alexander Ruf  Mourad Harir  Philippe Schmitt‐Kopplin   《Meteoritics & planetary science》2019,54(7):1431-1461

A carbonaceous chondrite was recovered immediately after the fall near the village of Diepenveen in the Netherlands on October 27, 1873, but came to light only in 2012. Analysis of sodium and poly‐aromatic hydrocarbon content suggests little contamination from handling. Diepenveen is a regolith breccia with an overall petrology consistent with a CM classification. Unlike most other CM chondrites, the bulk oxygen isotopes are extremely ¹⁶O rich, apparently dominated by the signature of anhydrous minerals, distributed on a steep slope pointing to the domain of intrinsic CM water. A small subset plots closer to the normal CM regime, on a parallel line 2 ‰ lower in δ¹⁷O. Different lithologies in Diepenveen experienced varying levels of aqueous alteration processing, being less aqueously altered at places rather than more heated. The presence of an agglutinate grain and the properties of methanol‐soluble organic compounds point to active impact processing of some of the clasts. Diepenveen belongs to a CM clan with ~5 Ma CRE age, longer than most other CM chondrites, and has a relatively young K‐Ar resetting age of ~1.5 Ga. As a CM chondrite, Diepenveen may be representative of samples soon to be returned from the surface of asteroid (162173) Ryugu by the Hayabusa2 spacecraft.  相似文献   

Microimaging spectroscopy and scanning electron microscopy of Northwest Africa 8657 shergottite: Interpretation of future in situ Martian data     

P. Manzari  S. De Angelis  M. C. De Sanctis  G. Agrosì  G. Tempesta 《Meteoritics & planetary science》2019,54(3):475-494

Microimaging spectroscopy is going to be the new frontier for validating reflectance remote sensed data from missions to solar system bodies. In this field, microimaging spectroscopy of Martian meteorites can provide important and new contributions to interpret data that will be collected by next instruments onboard rover missions to Mars, such as for example Exomars‐2020/Ma_MISS spectrometer. In this paper, a slab from the Northwest Africa (NWA) 8657 shergottite was studied using the SPectral IMager (SPIM) microimaging spectrometer, in the visible‐infrared (VIS‐IR) range, with the aim to subsequently validate the spectral data by means of different independent techniques. The validation was thus carried out, for the first time, comparing SPIM spectral images, characterized by high spatial and spectral resolution, with mineralogical–petrological analyses, obtained by scanning electron microscopy (SEM). The suitability of the SPIM resolution to detect and map augite, pigeonite, maskelynite, and other minor phases as calcite, Ca‐phosphates, and troilite/pyrrhotite with no loss of information about mineral distribution on the slab surface, was ascertained. The good agreement found between spectral and mineralogical data suggests that spectral‐petrography of meteorites may be useful to support in situ investigations on Martian rocks carried out by MaMiss spectrometer during Exomars2020 mission. Moreover, micro spectral images could be also useful to characterize, in a nondestructive way, Martian meteorites and other rare minerals occurring in meteorites. The results obtained in this work represent not only a methodological contribution to the study of meteorites but furnish also elements to reconstruct the history of this sample. The finding of zoned pyroxene, symplectitic texture, amorphous phases as maskelynite, and Fe‐merrillite permits us to hypothesize four stages, i.e., (1) igneous formation of rimmed pyroxenes and other minerals, (2) retrograde metamorphism, (3) shock by impact, and (4) secondary minerals by terrestrial contamination.  相似文献   

Instrument Calibration of the <Emphasis Type="Italic">Interface Region Imaging Spectrograph</Emphasis> (IRIS) Mission     

J.-P. Wülser  S. Jaeggli  B. De Pontieu  T. Tarbell  P. Boerner  S. Freeland  W. Liu  R. Timmons  S. Brannon  C. Kankelborg  C. Madsen  S. McKillop  J. Prchlik  S. Saar  N. Schanche  P. Testa  P. Bryans  M. Wiesmann 《Solar physics》2018,293(11):149

The Interface Region Imaging Spectrograph (IRIS) is a NASA small explorer mission that provides high-resolution spectra and images of the Sun in the 133?–?141 nm and 278?–?283 nm wavelength bands. The IRIS data are archived in calibrated form and made available to the public within seven days of observing. The calibrations applied to the data include dark correction, scattered light and background correction, flat fielding, geometric distortion correction, and wavelength calibration. In addition, the IRIS team has calibrated the IRIS absolute throughput as a function of wavelength and has been tracking throughput changes over the course of the mission. As a resource for the IRIS data user, this article describes the details of these calibrations as they have evolved over the first few years of the mission. References to online documentation provide access to additional information and future updates.  相似文献   

Sampling Density in Regional Exploration and Environmental Geochemical Studies: A Review     

Hosseini-Dinani  Hengameh  Mokhtari  Ahmad Reza  Shahrestani  Shahed  De Vivo  Benedetto 《Natural Resources Research》2019,28(3):967-994

Natural Resources Research - A variety of factors contribute to the proper and efficient evaluation of geochemical programs including sampling medium, sample size and sample fraction, sampling...  相似文献   

Artificial Fracture Stimulation of Rock Subjected to Large Isotropic Confining Stresses in Saline Environments: Application in Deep-Sea Gas Hydrate Recovery     

De Silva  V. R. S.  Ranjith  P. G.  Perera  M. S. A.  Wu  B. 《Natural Resources Research》2019,28(2):563-583

Natural Resources Research - The low permeability of gas hydrate deposits leads to poor extraction rates. Artificial fracture stimulation could significantly improve the recovery rate of an...  相似文献   

Flood-triggered versus earthquake-triggered turbidites: A sedimentological study in clastic lake sediments (Eklutna Lake,Alaska)     

Elke Vandekerkhove  Maarten Van Daele  Nore Praet  Veerle Cnudde  Peter J. Haeussler  Marc De Batist 《Sedimentology》2020,67(1):364-389

Lake sediments in Eklutna Lake, Alaska, reveal the presence of turbidites within varved sequences. These turbidites, which result from flood events and earthquakes, show a similar macroscopic appearance. In order to use turbidites to reconstruct flood variability and/or seismic history in the lake basin, it is crucial to determine the trigger of the turbidity currents. This study examined the turbidite caused by the ad 1964 Great Alaska earthquake as well as turbidites linked to historical flood events in order to differentiate between these earthquake-triggered and flood-triggered turbidites. In a suite of samples from throughout the lake, distinctive proxies are identified that can be associated with event-specific flow characteristics. The study presents straightforward discrimination methods related to the sedimentology and geochemical components of the turbidites. These methods are also applicable to other lakes, particularly proglacial lakes where the sediment composition of onshore and offshore sources is similar. Finally, the discrimination of the turbidite trigger can be used to reconstruct the palaeoflood and seismic history.  相似文献   

Timing,magnitude and geochemistry of major Southeast Asian volcanic eruptions: identifying tephrochronologic markers     

Caroline Bouvet De Maisonneuve  Olga Bergal-Kuvikas 《第四纪科学杂志》2020,35(1-2):272-287

We review the current knowledge about Southeast Asian volcanoes and their eruption histories, and focus on identifying tephrochronologic markers representing major explosive eruptions in order to further future palaeoclimate and volcanological studies. Forty-one volcanic edifices in Southeast Asia have been classified as large calderas by Whelley et al. (2015) and thus have, or are likely to have, produced large explosive eruptions with a Volcanic Explosivity Index (VEI) of 6–8. Unfortunately, only 20 such eruptions have known ages, spanning from 1.2 Ma to 1991 ad , and fewer have geochemical data that can be used for tephrostratigraphic correlations. Volcanic products from different geodynamic regions and different sources can generally be distinguished on major element plots (e.g. K₂O versus CaO) of matrix glass composition. However, the distinction of multiple eruptions from the same source often requires additional data such as trace element compositions of matrix glass and/or mineral compositions. Biotite, but also magnetite compositions (MgO and TiO₂ content in particular) appear to be very discriminating. Up to nine tuffs in addition to the three to four Toba tuffs can be utilised as widespread tephrochronologic markers and span a range from 1.2 to 1.6 Ma to recent. As only a few Holocene major eruptions have been well characterised and dated, many large calderas are still unstudied, and many distal tephra layers are still lacking a source, more tephrochronologic markers can certainly be defined in the future.  相似文献   

Composite robust active control of seismically excited structures with actuator dynamics     

N. Luo  J. Rodellar  M. De Le Sen 《地震工程与结构动力学》1998,27(3):301-311

In this paper, composite robust active control schemes are proposed for a class of non-linear base isolated structures in the presence of unknown seismic excitation, parametrical uncertainties and actuator dynamics. Only the information on state variables of the structural base and the first floor of the main structure has been used in the control design. A numerical simulation example is given for a ten-storeyed base isolated structure under the El Centro earthquake to show the effectiveness of the proposed control scheme. © 1998 John Wiley & Sons, Ltd.  相似文献   

Inelastic seismic response of one-way plan-asymmetric systems under bi-directional ground motions     

Mario De Stefano  Giuseppe Faella  Roberto Ramasco 《地震工程与结构动力学》1998,27(4):363-376

The static design requirements of some seismic codes, such as the Eurocode 8 and—in most cases—the Uniform Building Code, to allow for the effects of earthquake excitation acting in a direction other than the principal axes of the structure do not apply to one-way asymmetric systems. Therefore, with some exceptions, no specific provisions are considered for such systems to cover effects of structural asymmetry on the behaviour of elements located along the symmetric system direction. Aimed towards fulfilling this need, in this paper, a wide parametric study of the inelastic response of one-way asymmetric systems designed according to Uniform Building Code is carried out, considering two-component earthquake excitations. The analyses show that the maximum ductility demands on elements aligned along the asymmetric system direction are very close to, and even lower than, those obtained for symmetric reference systems. Conversely, the symmetric direction elements undergo significantly larger inelasticity than if they were located in symmetric reference systems. Subsequently, the overstrength needed by the symmetric direction elements to prevent such additional ductility demands for several stiffness and plan configurations is quantified. It is concluded that one-way asymmetry should be considered by seismic codes as an intrinsic system property, thus implying that specific provisions should be included for designing elements located along the symmetric system direction, in addition to those currently subscribed to design the asymmetric direction elements. © 1998 John Wiley & Sons, Ltd.  相似文献