检索结果-南通市图书馆

Micro-site Conditions of Epiphytic Orchids in a Human Impact Gradient in Kathmandu Valley, Nepal

Journal of Mountain Science 2012年第3期9卷 331-342页

作者： Yagya Prasad AdHIKARI anton FISCHER Hagen Siegfried FISCHER Geobotany Department of Ecology and Ecosystem Management Technische Universitt München Hans-Carl-von-Carlowitz-Platz 2 D-85354 Freising Germany

We studied distribution and site conditions of epiphytic orchids in a gradient of human interference in Kathmandu valley, central Nepal. The aim was to understand the recent distribution pattern of epiphytic orchids, with respect to (i) the micro-site conditions and (ii) the type and intensity of land use. The occurrence of epiphytic orchids was recorded for a grid with 1.5 km cell size. The cells represent different types and intensities of human impact. Site factors such as bark rugosity, bark pH, diameter at breast height (dbh; 1.3 m) of host trees, exposure to wind and sunlight intensity were recorded. With regard to the species richness and abundance of epiphytic orchids, we compared different human impact categories from very strong human impact (settlement area) to very low human impact (national park). Remote sensing was used for a supervised classification of land cover. Ficus religiosa turned out to be the most important host species for orchids in urban areas, while Schima wallichii and Alnus nepalensis significantly host orchids in the other categories. Both species richness and abundance of epiphytic orchids were significantly higher under very low human impact (forest in national park) and also some remaining patches of primary forest than the other regions. Micro-climate is crucial for orchid populations. Host bark pH, bark rugosity, sunlight intensity and host exposure were significantly different for all human impact categories in order to harbour epiphytic orchid species. Habitats with a mixture of mature trees are suitable and essential for the conservation of viable populations of epiphytic orchids in settled areas. The study reveals that to improve the population size of orchids it is essential for future urban forestry to: (i) Protect old trees as carriers of existing epiphytic orchid diversity, (ii) protect medium old trees to ensure that they may become old trees, (iii) plant new host trees for the future, (iv) plant in groups instead of sing

关键词： Human impact Host tree Micro-climate Epiphytic orchids Remote sensing Conservation Nepal

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

double-ejection micro-cathode arc thruster applied to micro-satellite

引用

High Voltage 2023年第1期8卷 102-110页

作者： Jia Tian Wenzheng Liu anton Nikiforov Nathalie de Geyter Rino Morent School of Electrical Engineering Beijing Jiaotong UniversityBeijingChina Research Unit Plasma Technology(RUPT) Department of Applied PhysicsGhent UniversityGhentBelgium

An innovative double-ejection micro-cathode arc thruster(AC_(d-μ)CAT),which consists of a cylindrical inner anode,a cylindrical outer cathode and two insulating sleeves(an inner insulating sleeve and an outer insulating sleeve),was *** differences in electrical characteristics,plasma parameters and propulsion performance between the newly proposed AC_(d-μ)CAT and a traditionalμCAT were *** results showed that compared to the traditionalμCAT structure,by using the AC_(d-μ)CAT,the peak value of produced thrust was increased 9.3 times,while the amplitude of the ion current and the ion-to-arc ratio were increased 5.4 and 5.9 times(from 1.2%to 7.1%),*** addition,data from Langmuir probe experiments indicated that peak values of the directional propagation speed and density of plasma plume were increased 3.1 times and 4.2 times,***,plasma plume directional ejection performance was also significantly *** study result will provide support for the development of a new-generationμCAT.

关键词： cylindrical inner outer

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

Fast Square Root Calculation without division for High Performance Control Systems of Power Electronics

引用

CES Transactions on Electrical Machines and Systems 2022年第2期6卷 145-152页

作者： anton dianov Alecksey Anuchin Alexey Bodrov daeyoung R&d center 16954YonginKorea National Research University“Moscow Power Engineering Institute” 111250MoscowRussia School of Engineering the University of ManchesterManchesterUK

The calculation of square roots is a frequently used operation in control systems of power electronics for different applications:motor drives,power converters,*** the same time,the execution of this procedure significantly loads microcontrollers and uses its power,which can be utilized for performing other important ***,it restricts the size of code,which can be processed by the microcontroller and compels developers to limit the number of functions,or to decrease execution frequency of a ***,the calculation of square roots is a bottle-neck in implementation of high-performance control systems,thus effective optimization of this task is extremely important in modern and efficient *** respect that many applications do not need precise calculation of square roots,the optimization of execution time can be achieved by decreasing of precision of the *** proposed technique is based on the approximation of parabola with hyperbola,which allows you to rapidly find the approximate value of a square *** into account that many digital signal processors(dSP)are not equipped with an effective divider,the developed algorithm does not use divisions,so it can be executed *** payback for this optimization is approximation error with a maximum of 0.5%,however,it is acceptable for the overwhelming majority of control systems.

关键词： Approximate computing Approximation algorithms Newton method Numerical methods

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

The structural basis of oscillation damping in plant stems-biomechanics and biomimetics

引用

Journal of Bionic Engineering 2004年第3期1卷 149-158页

作者： Hanns-Christof Spatz anton Emanns Olga Speck Competence Network Biomimetics Plant Biomechanics Group Fakultt für Biologie Albert-Ludwigs-Universitt Freiburg Schnzlestr. 1 D –79104 Freiburg GermanyCompetence Network Biomimetics Plant Biomechanics Group Fakultt für BiologieAlbert-Ludwigs-Universitt Freiburg Schnzlestr. 1 D –79104 Freiburg GermanyCompetence Network Biomimetics Plant Biomechanics Group Fakultt für BiologieAlbert-Ludwigs-Universitt Freiburg Schnzlestr. 1 D –79104 Freiburg Germany

Oscillations and their damping were investigated for plant stems of Cyperus alternifolius L., Equisetum hyemale L., Equisetum fluviatile L., Juncus effuses L., Stipa gigantea Link, and Thamnocalamus spathaceus (Franch.) Soderstr. With the exception of T. spathaceus, mechanical damping of the oscillation of individual plant stems, even without side organs, leaves or inflorescences, is quite effective. Our experiments support the hypothesis that embedding stiff sclerenchymatous elements in a more compliant parenchymatous matrix provides the structural basis for the dissipation of mechanical energy in the plant stem. As an application the naturally occurring structures were mimicked in a compound material made from hemp fabrics em- bedded in polyurethane foam, cured under pressure. Like its natural model it shows plastic deformability and viscoelastic be- haviour. In particular the material is characterized by a remarkably high shock absorption capacity even for high impact loads.

关键词： biomechanics biomimetics compound materials damped oscillations plants shock absorption viscoelasticity.

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

Ultra‑Transparent and Multifunctional IZVO Mesh Electrodes for Next‑Generation Flexible Optoelectronics

引用

Nano-Micro Letters 2025年第1期17卷 293-309页

作者： Kiran A.Nirmal Tukaram d.dongale Atul C.Khot Chenjie Yao Nahyun Kim Tae Geun Kim School of Electrical Engineering Korea UniversityAnam‑ro 145Seongbuk‑guSeoulRepublic of Korea Computational Electronics and Nanoscience Research Laboratory School of Nanoscience and BiotechnologyShivaji UniversityKolhapur 416004India

Mechanically durable transparent electrodes are essential for achieving long-term stability in flexible optoelectronic ***,they are crucial for applications in the fields of energy,display,healthcare,and soft *** meshes represent a promising alternative to traditional,brittle,metal oxide conductors due to their high electrical conductivity,optical transparency,and enhanced mechanical *** this paper,we present a simple method for fabricating an ultra-transparent conducting metal oxide mesh electrode using selfcracking-assisted *** this method,we produced an electrode with ultra-transparency(97.39%),high conductance(Rs=21.24Ωsq^(−1)),elevated work function(5.16 eV),and good mechanical *** also evaluated the effectiveness of the fabricated electrodes by integrating them into organic photovoltaics,organic light-emitting diodes,and flexible transparent memristor devices for neuromorphic computing,resulting in exceptional device *** addition,the unique porous structure of the vanadium-doped indium zinc oxide mesh electrodes provided excellent flexibility,rendering them a promising option for application in flexible optoelectronics.

关键词： Self-cracking template Vanadium-doped indium zinc oxide mesh Organic solar cells Organic light-emitting diodes Flexible transparent memory

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

Improved organs at risk segmentation based on modified U‐Net with self‐attention and consistency regularisation

引用

CAAI Transactions on Intelligence Technology 2024年第4期9卷 850-865页

作者： Maksym Manko anton Popov Juan Manuel Gorriz Javier Ramirez Electronic Engineering department Igor Sikorsky Kyiv Polytechnic InstituteKyivUkraine department of Signal Theory Telematics and CommunicationsUniversity of GranadaGranadaSpain

Cancer is one of the leading causes of death in the world,with radiotherapy as one of the treatment *** planning starts with delineating the affected area from healthy organs,called organs at risk(OAR).A new approach to automatic OAR seg-mentation in the chest cavity in Computed Tomography(CT)images is *** proposed approach is based on the modified U‐Net architecture with the ResNet‐34 encoder,which is the baseline adopted in this *** new two‐branch CS‐SA U‐Net architecture is proposed,which consists of two parallel U‐Net models in which self‐attention blocks with cosine similarity as query‐key similarity function(CS‐SA)blocks are inserted between the encoder and decoder,which enabled the use of con-sistency *** proposed solution demonstrates state‐of‐the‐art performance for the problem of OAR segmentation in CT images on the publicly available SegTHOR benchmark dataset in terms of a dice coefficient(oesophagus-0.8714,heart-0.9516,trachea-0.9286,aorta-0.9510)and Hausdorff distance(oesophagus-0.2541,heart-0.1514,trachea-0.1722,aorta-0.1114)and significantly outperforms the *** current approach is demonstrated to be viable for improving the quality of OAR segmentation for radiotherapy planning.

关键词： 3‐d computer vision deep learning deep neural networks image segmentation medical image processing object segmentation

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

A Perturbation Result for dynamical Contact Problems

引用

Numerical Mathematics(Theory,Methods and Applications) 2009年第3期2卷 237-257页

作者： Corinna Klapproth Peter deuflhard anton Schiela Zuse Institute Berlin(ZIB) Takustrasse7D-14195 Berlin-DahlemGermany

This paper is intended to be a first step towards the continuous dependence of dynamical contact problems on the initial data as well as the uniqueness of a solution. Moreover,it provides the basis for a proof of the convergence of popular time integration schemes as the Newmark *** study a frictionless dynamical contact problem between both linearly elastic and viscoelastic bodies which is formulated via the Signorini contact *** viscoelastic materials fulfilling the Kelvin-Voigt constitutive law,we find a characterization of the class of problems which satisfy a perturbation result in a non-trivial mix of norms in function *** characterization is given in the form of a stability condition on the contact stresses at the contact ***,we present perturbation results for two well-established approximations of the classical Signorini condition:The Signorini condition formulated in velocities and the model of normal compliance,both satisfying even a sharper version of our stability condition.

关键词： dynamical contact problems stability (visco-)elasticity Signorini condition Newmarkmethod.

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

Hot Articles Forecasting System Based on the Headline Analysis with deep Learning

Hot Articles Forecasting System Based on the Headline Analys...

引用

作者： anton VORONOV 上海交通大学

学位级别：硕士

Forecasting popularity of the articles become one hot task for the news media industry and the research community have provided several prediction systems,based on popular trends,metadata and users ***,when the headline has a fundamental relationship with the popularity of the article,there is no proper system,which can use only the title to predict the possible views *** theses work proposes a new Hot Articles Forecasting System based on the headline analysis with Online deep Neural Network architecture and Bottleneck compression technique,which can make an efficient real-time prediction of the article popularity and automatically learn new ***,this work introduces three new datasets based on the Chinese and Russian languages,with over than 800 000 samples in *** advanced,this thesis provides the corporation of the formal and informal language style headlines in the case of the popularity prediction for the Chinese *** work also investigates the challenges and provides solutions related to the popularity prediction and the headline *** work will show that the HAFS can provide prediction results with different languages in the case of changing activity and trends.

关键词：

来源：

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Soil Conservation and Sediment Control in Europe

引用

长江科学院院报 2010年第9期27卷 83-86页

作者： anton Charles Imeson Foundation 3d Environmental Change Curtiuslaan 14 1851 AM Heiloo The Netherlands

The objective of this paper is to provide an overview of soil conservation and sediment control in Europe from the perspectives of policy makers seeking solutions to current problems of soil loss and *** and information are derived from detailed reports written in support of the European Soils directive,that addressed the threats facing European soils and from workshops organised to identify best practices and achieve sustainable land use in different EU *** were organised by the SCAPE(Strategies for Soil Conservation and Protection in Europe) supporting *** technical measures used to limit erosion and restore ecosystems,there is much similarity between Europe and *** main soil and land degradation problems that soil conservation practitioners and scientists have to address are caused by land use and management impacts that have proved difficult or impossible to resist because of political *** political leadership that regarded soil conservation and sediment control,as a cornerstone of sustainable economic development,which seemed to be present eight years,is urgently required once more.

关键词： soil conservation sustainable land management European soil policy

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

The Mg-carbonate-Fe interaction:Implication for the fate of subducted carbonates and formation of diamond in the lower mantle

引用

Geoscience Frontiers 2019年第4期10卷 1449-1458页

作者： Naira S.Martirosyan Konstantin d. Litasov Sergey S. Lobanov Alexander F. Goncharov anton Shatskiy Hiroaki Ohfuji Vitali Prakapenka Sobolev Institute of Geology and Mineralogy Russian Academy of ScienceKoptyuga ave.3Novosibirsk630090Russia Geophysical Laboratory Carnegie Institution for ScienceWashingtonDC20015USA Novosibirsk State University Pirogova st.2Novosibirsk630090Russia Geodynamic Research Center Ehime UniversityMatsuyamaEhime790-8577Japan Center for Advanced Radiation Sources University of ChicagoChicagoIL60637USA

The fate of subducted carbonates in the lower mantle and at the core-mantle boundary was modelled via experiments in the MgCO3-Fe^0 system at 70-150 GPa and 800-2600 Kin a laser-heated diamond anvil *** in situ synchrotro n X-ray diffraction and ex situ transmission electron microscopy we show that the reduction of Mg-carbonate can be exemplified by:6 MgCO3+19 Fe=8 FeO+10(Mg0.6Fe^0.4)O+Fe7 C3+3 *** presented results suggest that the interaction of carbonates with Fe^0 or Fe^0-bearing rocks can produce Fe-carbide and diamond,which can accumulate in the d"region,depending on its carbon to Fe *** to the sluggish kinetics of the transformation,diamond can remain metastable at the core-mantle boundary(CMB)unless it is in a direct contact with *** addition,it can be remobilized by redox melting accompanying the generation of mantle plumes.

关键词： deep carbon cycle Carbonate Carbide High pressure Redox reaction

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：