检索结果-南通市图书馆

Quantifying land degradation in the Zoige Basin,NE Tibetan Plateau using satellite remote sensing data

Journal of Mountain Science 2017年第1期14卷 77-93页

作者： YU Kai-feng frank LEHMKUHL Dimitri FALK Department of Geography RWTH Aachen University Templergraben 55 52056 Aachen Germany

Considerable efforts have been dedicated to desertification research in the arid and semi-arid drylands of central Asia. However,there are few quantitative studies in conjunction with proper qualitative evaluation concerning land degradation and aeolian activity in the alpine realm. In this study,spectral information from two Landsat-5 TM scenes(04.08.1994 and 28.07.2009,respectively) was combined with reference information obtained in the field to run supervised classifications of eight landscape types for both time steps. Subsequently,the temporal and spatial patterns of the alpine wetlands/grasslands evolutions in the Zoige Basin were quantified and assessed based on these two classification maps. The most conspicuous change is the sharp increase of ~627 km^2 degraded meadow. Concerning other land-covers,shallow wetland increases ~107 km^2 and aeolian sediments(mobile dunes and sand sheets) have an increase of ~30 km^2. Considering the deterioration,an obvious decrease of ~440 km^2 degraded wetland can be observed. Likewise,decrease of deep wetland(~78 km^2),humid meadow(~80 km^2) and undisturbed meadow(~88 km^2) were determined. These entire evolution matrixes undoubtedly hint a deteriorating tendency of the Zoige Basin ecosystem,which is characterized by significantly declined proportion of intact wetlands,meadow,rangeland and a considerable increase ofdegraded meadow and larger areas of mobile dunes. In particular,not only temporal alteration of the landcover categories,the spatial and topographical characteristics of the land degradation also deserves more attention. In the alpine rangelands,the higher terraces of the river channels along with their slopes are more liable to the degradation and desertification. This tendency has significantly impeded the nomadic and agriculture activities. The set of anthropozoogenic factors encompassing enclosures,overgrazing and trampling,rodent damaging and exceedingly ditching in the wetlands are assumed to be the main co

关键词： Alpine ecosystem Wetlands Degradation Desertification Zoige Basin Driving mechanisms

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Emission properties of nanolasers during the transition to lasing

引用

Light(Science & Applications) 2014年第1期3卷 92-99页

作者： Weng W Chow frank Jahnke Christopher Gies Sandia National Laboratories AlbuquerqueNM 87185-1086USA Institute for Theoretical Physics University of Bremen28334 BremenGermany

This review addresses ongoing discussions involving nanolaser experiments,particularly those related to thresholdless lasing or few-emitter devices.A quantum-optical(quantum-mechanical active medium and radiation field)theory is used to examine the emission properties of nanolasers under different experimental *** active medium is treated as inhomogeneously broadened semiconductor quantum dots embedded in a quantum well,where carriers are introduced via current *** are made between a conventional laser and a nanolaser with a spontaneous emission factor of unity,as well as a laser with only a few quantum dots providing the *** is found that the combined exploration of intensity,coherence time,photon autocorrelation function and carrier spectral hole burning can provide a unique and consistent picture of nanolasers in the new regimes of laser operation during the transition from thermal to coherent ***,by reducing the number of quantum dots in the optical cavity,a clear indication of non-classical photon statistics is observed before the single-quantum-dot limit is reached.

关键词： nanolasers optoelectronics photon statistics quantum light sources quantum optics semiconductor quantum dots thresholdless lasing

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Use of Internet Technology for the Improvement of Execution Management in Geotechnical Engineering Projects

引用

Tsinghua Science and Technology 2008年第S1期13卷 132-137页

作者： Peter Degebrodt Marcus Mejstrik frank Rackwitz Stavros Savidis frank Schley Klaus-Peter Holz Chair of Soil Mechanics and Geotechnical Engineering Berlin Institute of Technology Lehrstuhl Bauinformatik Brandenburg University of Technology at Cottbus

An internet-based information and monitoring platform for the specific requirements of geotechnical engineering projects is presented. The platform is based on a hybrid-model approach consisting of a model-based information management system and a resource management system, the latter also referred to as DCMS. Project key information can be accessed via the main user interface, the 'graphical navigator'. The graphical navigator provides also a direct access to additional information in the DCMS. Prompt reac-tion in exceptional situations as well as in daily work gets an extensive support. In practical applications it has been proven that this platform seems to be an adequate tool especially for risk assessment and management in geotechnical engineering projects. Components and advantages of the platform as well as ex periences from the applications are presented and discussed in the paper.

关键词： information & execution & risk management internet monitoring geotechnical engineering

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

HIV protease:late action to prevent immune detection

引用

Signal Transduction and Targeted Therapy 2021年第5期6卷 1408-1409页

作者： Konstantin M.J.Sparrer frank Kirchhoff Institute of Molecular Virology Ulm University Medical CenterUlmGermany

A recent study published in Science by Wang and colleagues shows that premature activation of the HIV-1 protease leads to caspase activation and recruitment domain 8(CARD8)inflammasome-mediated pyroptosis of infected macrophages and CD4+T cells(Fig.1).These findings might help to improve approaches aiming to eliminate the latent viral reservoirs upon HIV-1 *** invading viral pathogens trigger the innate immune system and are usually rapidly controlled and eventually *** sense viral intruders via so-called pattern recognition receptors(PRRs)capable of detecting pathogen-associated molecular patterns(PAMPs)allowing discrimination between self and *** many cases,these patterns are viral nucleic acids that show pathogen-specific structures or emerge at the wrong localization in the ***,activation of PRRs by their respective ligands leads to the induction of various anti-viral signaling cascades,among them the inflammasome.

关键词： eventually action eliminate

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High-quality perovskite MAPbI_3 single crystals for broad-spectrum and rapid response integrate photodetector

引用

Journal of Energy Chemistry 2018年第3期27卷 722-727页

作者： Yunxia Zhang Yucheng Liu Zhou Yang Shengzhong(frank)Liu Key Laboratory of Applied Surface and Colloid Chemistry National Ministry of Education Shaanxi Key Laboratory for Advanced Energy Devices ShaanxiEngineering Lab for Advanced Energy TechnologyInstitute for Advanced Energy MaterialsSchool of Materials Science and EngineeringShaanxi Normal UniversityXi'an 710119ShaanxiChina iChEM Dalian National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

Organic–inorganic single-crystalline perovskites have attracted significant attentions due to their exceptional progress in intrinsic properties＇ investigation and applications in photovoltaics and optoelectronics. In this study, the large perovskite CH3NH3PbI3 single crystal with the largest length of 80 mm was prepared through the method of inverse-temperature crystallization. Meanwhile, the mass production of integrate photodetectors have been fabricated on the single-crystalline wafer and the photoresponse performances were investigated. The results show that the single-crystalline photodetectors have broad spectrum response to 900 nm, rapid response speed（〈40 μs） and excellent stability. These findings are of great importance for future promising perovskite single crystalline for integrated photoelectronic application.

关键词： Single-crystalline Perovskite Photodetector Rapid response

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Heterogeneous multi-player imitation learning

引用

Control Theory and Technology 2023年第3期21卷 281-291页

作者： Bosen Lian Wenqian Xue frank L.Lewis Department of Electrical and Computer Engineering Auburn UniversityAuburnAL 36849USA State Key Laboratory of Synthetical Automation for Process Industries and International Joint Research Laboratory of Integrated Automation Northeastern UniversityShenyang 110819LiaoningChina UTA Research Institute University of Texas at Arlington(UTA)Fort WorthTX 76118USA

This paper studies imitation learning in nonlinear multi-player game systems with heterogeneous control input *** propose a model-free data-driven inverse reinforcement learning(RL)algorithm for a leaner to find the cost functions of a N-player Nash expert system given the expert's states and control *** allows us to address the imitation learning problem without prior knowledge of the expert's system *** achieve this,we provide a basic model-based algorithm that is built upon RL and inverse optimal *** serves as the foundation for our final model-free inverse RL algorithm which is implemented via neural network-based value function *** analysis and simulation examples verify the methods.

关键词： Imitation learning Inverse reinforcement learning Heterogeneous multi-player games Data-driven model-free control

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Seed-assisted growth for high-performance perovskite solar cells:A review

引用

Journal of Energy Chemistry 2024年第9期96卷 588-610页

作者： Zhimin Fang Ting Nie Jianning Ding Shengzhong(frank)Liu Institute of Technology for Carbon Neutralization Yangzhou UniversityYangzhou 225127JiangsuChina Dalian National Laboratory for Clean Energy iChEMDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina Key Laboratory of Applied Surface and Colloid Chemistry Ministry of EducationShaanxi Key Laboratory for Advanced Energy DevicesShaanxi Engineering Lab for Advanced Energy TechnologySchool of Materials Science and EngineeringShaanxi Normal UniversityXi’an 710119ShaanxiChina

The rapid increase in the power conversion efficiency(PCE)of perovskite solar cells(PSCs)is closely related to the development of deposition techinique for perovskite *** high-quality perovskite film enables efficient charge transportation and less trap states,which are eventually translated into enhanced device ***-assisted growth(SAG)is a potential technique for depositing highly-crystallized perovskite films with preferential crystal orientation among the numerous approaches related to crystallization *** this review,we summarize the recent advances in the SAG technique for both one-step and two-step processed perovskite ***,seeding at the buried interface and on the top surface are also *** present different seeds and their corresponding seeding mechanism in detail,such as inorganic nanomaterials,organic ammoniums,alkali metal halides,and perovskite ***,challenges and perspectives are proposed to investigate the potential expansion of seeding engineering in high-performance PSCs,particularly large-area devices.

关键词： Perovskite solar cell Seed Crystallization Efficiency

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Neuronal avalanches:Sandpiles of self-organized criticality or critical dynamics of brain waves?

引用

Frontiers of physics 2023年第4期18卷 337-348页

作者： Vitaly L.Galinsky Lawrence R.frank Center for Scientific Computation in Imaging University of California at San DiegoLa JollaCA 92037-0854USA Center for Functional MRI University of California at San DiegoLa JollaCA 92037-0677USA

Analytical expressions for scaling of brain wave spectra derived from the general nonlinear wave Hamiltonian form show excellent agreement with experimental“neuronal avalanche”*** theory of the weakly evanescent nonlinear brain wave dynamics[*** 2,023061(2020);*** Neurosci.32,2178(2020)]reveals the underlying collective processes hidden behind the phenomenological statistical description of the neuronal avalanches and connects together the whole range of brain activity states,from oscillatory wave-like modes,to neuronal avalanches,to incoherent spiking,showing that the neuronal avalanches are just the manifestation of the different nonlinear side of wave processes abundant in cortical *** a more broad way these results show that a system of wave modes interacting through all possible combinations of the third order nonlinear terms described by a general wave Hamiltonian necessarily produces anharmonic wave modes with temporal and spatial scaling properties that follow scale free power *** the best of our knowledge this has never been reported in the physical literature and may be applicable to many physical systems that involve wave processes and not just to neuronal avalanches.

关键词： nonlinear waves critical exponent Hamiltonian system neuronal avalanches critical dynamics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Forecasting the effects of EU policy measures on the nitrate pollution of groundwater and surface waters

引用

Journal of Environmental Sciences 2010年第6期22卷 872-877页

作者： Ralf Kunkel Peter Kreins Bjrn Tetzlaff frank Wendland Research Centre Jülich Institute of Chemistry and Dynamics of the Geosphere Institute of Rural Studies Federal Agricultural Research Centre

We used the interdisciplinary model network REGFLUD to predict the actual mean nitrate concentration in percolation water at the scale of the Weser river basin （Germany） using an area differentiated （100 m × 100 m） approach. REGFLUD combines the agro-economic model RAUMIS for estimating nitrogen surpluses and the hydrological models GROWA/DENUZ for assessing the nitrate leaching from the soil. For areas showing predicted nitrate concentrations in percolation water above the European Union （EU） groundwater quality standard of 50 mg NO3-N/L, effective agri-environmental reduction measures need to be derived and implemented to improve groundwater and surface water quality by 2015. The effects of already implemented agricultural policy are quantified by a baseline scenario projecting the N-surpluses from agricultural sector to 2015. The REGFLUD model is used to estimate the effects of this scenario concerning groundwater and surface water pollution by nitrate. From the results of the model analysis the needs for additional measures can be derived in terms of required additional N-surplus reduction and in terms of regional prioritization of measures. Research work will therefore directly support the implementation of the Water Framework Directive of the European Union in the Weser basin.

关键词： catchment management diffuse source pollution mitigation methods river basin management Water Framework Directive

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Path towards high-efficient kesterite solar cells

引用

Journal of Energy Chemistry 2018年第4期27卷 1040-1053页

作者： Dongxiao Wang Wangen Zhao Yi Zhang Shengzhong(frank)Liu Institute of Photoelectronic Thin Film Devices and Technology and Key Laboratory of Photoelectronic Thin Film Devices and Technology Tianjin Nankai UniversityTianjin 300071China Key Laboratory for Applied Surface and Colloid Chemistry National Ministry of EducationShaanxi Engineering Lab for Advanced Energy TechnologySchool of Materials Science and EngineeringShaanxi Normal UniversityXi'an 710062ShaanxiChina Dalian National Laboratory for Clean Energy iChEM(Collaborative Innovation Center of Chemistry for Energy Materials)Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023.LiaonigChina

Kesterite structure semiconductor Cu2ZnSn（S,Se）4 is one of the most promising candidate as a light absorber material to overtake the next generation of thin film solar cells, owing to its low cost, non-toxic, and earth abundant source materials. The Sbockley-Queisser limit of the single junction Cu2ZnSn（S,Se）4 solar cell is over 30%, signifying a large potential of this family of solar cells. In the past years, with the development of synthesis techniques, Cu2ZnSn（S,Se）4 solar cells have attracted considerable atten- tion and the power conversion efficiency of Cu2ZnSn（S,Se）4 solar cell has experienced a rapid progress. Presently, the certified champion efficiency of CZTSSe solar cells has reached to 12.6%, which is far below the efficiency of Cu（ln,Ga）Se2 solar cell. In this review, the developments of Cu2ZnSn（S,Se）4 solar cells in recent years are briefly reviewed. Then the fundamental understanding of Cu2ZnSn（S,Se）4 solar cells is introduced, including materials and device structure, as well as the band alignment of hetero-junction and their impacts on device performance. After that, we mainly review the progress and achievements in the preparation processes, through vacuum and non-vacuum based processes. Finally, we outline the challenges and perspectives of this promising solar cell.

关键词： Kesterite CZTS Thin film solar cells

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：