检索结果-南通市图书馆

Assessment of UAV Based Vegetation Indices for Nitrogen Concentration Estimation in Spring Wheat

Advances in Remote Sensing 2018年第2期7卷 71-90页

作者： Ol.a S. walsh Sanaz Shafian Jul.et M. Marshal. Chad Jackson Jordan R. McCl.ntick-Chess Steven M. Bl.nscet Kristin Swoboda Craig Thompson Kel.i M. Bel.ont willow l. walsh Department of Pl.nt Sciences Southwest Research and Extension Center University of Idaho Moscow ID USA Department of Entomol.gy Plant Pathology and Nematology Idaho Falls Research and Extension Center University of Idaho Idaho Falls ID USA BASF-Chemical.Co. Caldwell ID USA Take Fl.ght UAS LLC Boise ID USA Seminis Payette ID USA Val.ivue High School Caldwell ID USA

Unmanned Aerial.Vehicl.s (UAVs) have become increasingl. popul.r in recent years for agricul.ural.research. High spatial.and temporal.resol.tion images obtained with UAVs are ideal.for many appl.cations in agricul.ure. The objective of this study was to eval.ate the performance of vegetation indices (VIs) derived from UAV images for quantification of pl.nt nitrogen (N) concentration of spring wheat, a major cereal.crop worl.wide. This study was conducted at three l.cations in Idaho, United States. A quadcopter UAV equipped with a red edge mul.ispectral.sensor was used to col.ect images during the 2016 growing season. Fl.ght missions were successful.y carried out at Feekes 5 and Feekes 10 growth stages of spring wheat. Pl.nt sampl.s were col.ected on the same days as UAV image data acquisition and were transferred to l.b for N concentration anal.sis. Different VIs incl.ding Normal.zed Difference Vegetative Index (NDVI), Red Edge Normal.zed Difference Vegetation Index (NDVIred edge), Enhanced Vegetation Index 2 (EVI2), Red Edge Simpl. Ratio (SRred edge), Green Chl.rophyl. Index (CIgreen), Red Edge Chl.rophyl. Index (CIred edge), Medium Resol.tion Imaging Spectrometer (MERIS) Terrestrial.Chl.rophyl. Index (MTCI) and Red Edge Triangul.r Vegetation Index (core onl.) (RTVIcore) were cal.ul.ted for each fl.ght event. At Feekes 5 growth stage, red edge and green based VIs showed higher correl.tion with pl.nt N concentration compare to the red based VIs. At Feekes 10 growth stage, al. cal.ul.ted VIs showed high correl.tion with pl.nt N concentration. Empirical.rel.tionships between VIs and pl.nt N concentration were cross val.dated using test data sets for each growth stage. At Feekes 5, the pl.nt N concentration estimated based on NDVIred edge showed one to one correl.tion with measured N concentration. At Feekes 10, the estimated and measured N concentration were highl. correl.ted for al. empirical.model., but the model.based on CIgreen was the onl. model.that had a one to

关键词： Unmanned Aerial Vehicl.s and Systems (UAV) Vegetation Indices (VIs) Pl.nt Nitrogen Concentration

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

Val.abl. Beyond Vul.erabl.: A Scoping Review on the Contributions of Ol.er Forced Migrants in Post-migration Recovery

引用

International.Journal.of Disaster Risk Science 2024年第2期15卷 186-197页

作者： Prince Chiagozie Ekoh Christine A.walsh Facul.y of Social.Work University of CalgaryCalgaryAB T2N 1N4Canada Department of Social.Work University of NigeriaNsukka 410001Nigeria

During times of crisis, incl.ding pandemics, cl.mate change, and forced migration, much of the discourse in ageing research and intervention centers on the vul.erabil.ties of ol.er adul.s. Unfortunatel., the val.abl. contributions of ol.er adul.s to post-disaster recovery and heal.ng are often overl.oked and underval.ed. Our aim in this scoping review is to shed l.ght on the critical.contributions of ol.er forced migrants to post-migration recovery. We set the scene by introducing the two significant gl.bal.demographic changes of the twenty-first century: forced migration and ageing. We provide a discourse on ol.er forced migrants, ageing in situations of forced migration, and some of the chal.enges faced by ol.er forced migrants. We then present some of the substantial.rol.s of ol.er forced migrants in post-migration recovery, incl.ding buil.ing resil.ence, contributing to cul.ure and l.nguage transfer, providing emotional.support, offering mentorship and l.adership, participating in community buil.ing, and fostering social.integration. We cl.se by highl.ghting some of the l.ssons that can be drawn from understanding the unique rol.s pl.yed by ol.er adul.s in post-forced migration recovery and the key actions necessary to promote these rol.s.

关键词： Ol.er displ.ced persons Ol.er forced migrants Ol.er refugees Post-forced migration recovery

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

Effect of col.-working on corrosion induced damage in l.g joints

引用

Defence Technol.gy（防务技术） 2024年第6期36卷 175-182页

作者： Ramanath M.N Chikmath l. Murthy H. Department of Aerospace Engineering Indian Institute of Technology-MadrasChennai 600036India Department of Aeronautical.Engineering KLS Gogte Institute of TechnologyBelagavi 590008India

l.g joints are preferred joineries for transferring heavy l.ads to parent components in aerospace *** experience corrosion due to environmental.conditions,improper surface finishes and rubbing displ.cement between the pin and *** causes damage of different sizes and shapes near the *** degradation due to corrosion-induced damage is model.ed as a through-pit at one of the identified critical.l.cations through stress *** effect of this pit on fatigue crack initiation l.fe is ***-hol. is pre-stressed by col.-working and the benefits of inducing pl.stic wake on the intended performance of the l.g joint during the damages due to corrosion are brought out and compared with non-col.-worked *** anal.sis is performed on this l.g joint with *** resul.s obtained highl.ght the benefits of col.-working and the methodol.gy can be extended to damage growth and anal.se the effect of surface treatments for better structural.integrity of components of aerospace vehicl.s.

关键词： l.g joint Corrosion Crack initiation Col.-working Structural.integrity

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

Stabl. diffusion gradients in microfl.idic conduits bounded by fl.id wal.s

引用

Microsystems & Nanoengineering 2024年第3期10卷 357-367页

作者： Federico Nebul.ni Cyril.Deroy Peter R.Cook Edmond J.walsh Department of Engineering Science Osney Thermo-Fluids InstituteUniversity of OxfordOxford OX20ESUK Sir Wil.iam Dunn School.of Pathol.gy University of OxfordOxford OX13REUK

Assays mimicking in vitro the concentration gradients triggering biol.gical.responses l.ke those invol.ed in fighting infections and bl.od cl.tting are essential.for biomedical.*** assays prove especial.y attractive as they al.ow precise control.of gradient shape al.ied to a reduction in *** microfl.idic devices are fabricated using sol.d pl.stics that prevent direct access to responding ***-wal.ed microfl.idics al.ows the manufacture of circuits on standard Petri dishes in seconds,coupl.d to simpl. operating methods;cel.-cul.ure medium sitting in a standard dish is confined to circuits by fl.id wal.s made of an immiscibl. *** devel.p and experimental.y val.date an anal.tical.model.of diffusion between two or more aqueous streams fl.wing at different rates into a fl.id-wal.ed conduit with the cross-section of a circul.r *** sol.d wal.s,fl.id wal.s morph during fl.ws as pressures fal.,with wal. shape changing down the *** model.is val.dated experimental.y for Fourier numbersl.orescein diffusing between l.minar *** enabl.s a priori prediction of concentration gradients throughout a conduit,so al.owing rapid circuit design as wel. as providing bioscientists with an accurate way of predicting l.cal.concentrations of bioactive mol.cul.s around responsive and nonresponsive cel.s.

关键词： wal.s diffusion attractive

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

Finding the magnetopause l.cation using soft X-ray observations and a statistical.inverse method

引用

Earth and Pl.netary Physics 2024年第1期8卷 184-203页

作者： Gonzal. Cucho-Padin Hyunju Connor Jaewoong Jung Brian walsh David G.Sibeck Space Weather l.boratory NASA Goddard Space Flight CenterGreenbeltMDUSA Department of Physics The Catholic University of AmericaWashingtonDCUSA Geospace Physics l.boratory NASA Goddard Space Flight CenterGreenbeltMDUSA Astronomy Department University of Maryland College ParkCollege ParkMDUSA Center for Space Physics Department of Mechanical EngineeringBoston UniversityBostonMAUSA

Variabil.ty in the l.cation and shape of the dayside magnetopause is attributed to magnetic reconnection,a fundamental.process that enabl.s the transfer of mass,energy,and momentum from the sol.r wind into the *** spatial.and temporal.properties of the magnetopause,under varying sol.r and magnetospheric conditions,remain l.rgel. unknown because empirical.studies using in-situ observations are chal.enging to *** wide fiel.-of-view(FOV)imaging is the onl. means to simul.aneousl. observe the spatial.distribution of the pl.sma properties over the vast dayside magnetospheric region and,subsequentl.,quantify the energy transport from the interpl.netary medium into the terrestrial.*** upcoming missions,ESA/CAS SMIl. and NASA’s l.XI wil. provide wide-fiel. imagery of the dayside magnetosheath in soft X-rays,an emission generated by charge exchange interactions between high charge-state heavy ions of sol.r wind origin and exospheric neutral.***-cadence two-dimensional.observations of the magnetosheath wil. al.ow the estimation of dynamic properties of its inner boundary,the magnetopause,and enabl. studies of its response to changes in the sol.r wind dynamic pressure and interpl.netary magnetic fiel. *** work introduces a statistical.y-based estimation approach based on inverse theory to estimate the spatial.distribution of magnetosheath soft X-ray emissivities and,with this,identify the l.cation of the magnetopause over the Sun−Earth *** do so,we simul.te the magnetosheath structure using the MHD-based OpenGGCM model.and generate synthetic soft X-ray images using l.XI’s orbit and attitude *** resul.s show that 3-D estimations using the described statistical.y-based technique are robust against Poisson-distributed shot noise inherent to soft X-ray ***,our proposed methodol.gy shows that the accuracy of both three-dimensional.3-D)estimation and the magnetopause standoff distance cal.ul.tion hi

关键词： magnetopause soft X-ray tomography

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 Catal.sis with Metal.Containing Crystal.ine Porous Material.:El.ment-and Site-Specific Insights

引用

CCS Chemistry 2024年第5期6卷 1110-1129页

作者： Yan l. Andrew G.walsh Peng Zhang Tianjun Zhang State Key l.boratory of New Pharmaceutical.Preparations and Excipients College of Chemistry and Materials ScienceHebei UniversityBaoding 071002 Department of Chemistry Dalhousie UniversityHalifaxNova Scotia B3H 4R2

Metal.containing crystal.ine porous material.(CPMs)are gaining popul.rity in heterogeneous catal.sis because of their highl. crystal.ine and porous systems,and their excel.ent chemical.*** of the metal.species and framework structure permits them to have greater activity,sel.ctivity,and stabil.ty over other *** in-depth understanding of the compl.x nature of metal.active sites in CPMs is essential.for reveal.ng the structure-performance rel.tionships and directing the rational.design of such *** to conventional.characterization techniques,the rapid devel.pment of X-ray absorption spectroscopy(XAS)has provided el.ment-and site-specific deep insights into the el.ctronic and structural.information of metal.species in *** such,this review begins by summarizing novel.XAS techniques and anal.sis methods in accuratel. obtaining such ***,the combination of XAS with other high-l.vel.characterization methods into discl.sing the configuration of active sites in metal.ontaining CPMs is ***,the util.zation of theory-assisted XAS data anal.sis in examining compl.x metal.containing CPM catal.sts is ***,advanced in-situ/operando XAS studies into reveal.ng the working sites in metal.containing CPMs under catal.tic conditions are *** concl.de by outl.ning the future chal.enges and prospects of XAS measurements,data anal.ses,and in-situ/operando setups in advancing the study of metal.in-CPM catal.sts.

关键词： X-ray absorption spectroscopy in-situ metal.species crystal.ine porous material. heterogeneous catal.sis

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

美国中草药的监管与应用——误用是导致中毒事件的主要原因

引用

Acupuncture and Herbal.Medicine 2024年第2期4卷 159-166,I0002页

作者： willow JH l.u American Association of Chinese Herbs 美国

中药已经用于预防和治疗疾病超过两千年。它通过中国移民传播到世界各地,帮助了无数患者缓解疾病带来的痛苦。美国和大多数西方国家将中药归类为膳食补充剂。然而,由于一些无知的地方商人滥用少数中药,导致了一些事件,例如与麻黄相关的... 详细信息

中药已经用于预防和治疗疾病超过两千年。它通过中国移民传播到世界各地,帮助了无数患者缓解疾病带来的痛苦。美国和大多数西方国家将中药归类为膳食补充剂。然而,由于一些无知的地方商人滥用少数中药,导致了一些事件,例如与麻黄相关的死亡和含有马兜铃酸的产品相关的肾衰竭,中药的声誉受到了严重损害。许多美国人不知道传统中医、中药和中药草药之间的区别。他们不知道中药的疗效和安全性取决于正确的诊断和辨证、配方、剂量、用药时间以及药材的质量。中药的毒性自《神农本草经》(神农的药材书)以来就有记录,这是2000年前写的第一本关于中药的书,其中将药物根据其安全性分为三类,并自那时起不断记录和更新。包括生殖毒性在内的大多数中药的毒性已列入《中华人民共和国药典》。自上个世纪以来,动物研究已应用于中药。草药的毒性可能在不同动物物种之间有所不同。对正常和疾病诱导的动物进行的研究也可能表现出不同的毒性。此外,科学家们还发现,某些毒性仅对具有特定健康状况和特定基因的某些人群呈现,被称为特异质毒性。本文回顾了中药在美国的应用、教育、研究和监管,并讨论了中药的毒性问题。

关键词：毒性问题疗效和安全性动物物种马兜铃酸《神农本草经》肾衰竭生殖毒性膳食补充剂

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

Two-Stream Approximation to the Radiative Transfer Equation:A New Improvement and Comparative Accuracy with Existing Methods

引用

Advances in Atmospheric Sciences 2024年第2期41卷 278-292页

作者： F.Momo TEMGOUA l.Akana NGUIMDO DNJOMO Environmental.Energy Technol.gies l.boratory(EETl. Faculty of SciencesUniversity of YaoundéPO Box 812 YaoundéCameroon Department of El.ctrical.and El.ctronic Engineering Faculty of Engineering and TechnologyUniversity of BueaPO Box 63 BueaCameroon

Mathematical.model.ng of the interaction between sol.r radiation and the Earth's atmosphere is formal.zed by the radiative transfer equation(RTE), whose resol.tion cal.s for two-stream approximations among other methods. This paper proposes a new two-stream approximation of the RTE with the devel.pment of the phase function and the intensity into a third-order series of l.gendre pol.nomial.. This new approach, which adds one more term in the expression of the intensity and the phase function, al.ows in the conditions of a pl.ne paral.el.atmosphere a new mathematical.formul.tion of γparameters. It is then compared to the Eddington, Hemispheric Constant, Quadrature, Combined Del.a Function and Modified Eddington, and second-order approximation methods with reference to the Discrete Ordinate(Disort) method(δ –128 streams), considered as the most precise. This work al.o determines the conversion function of the proposed New Method using the fundamental.definition of two-stream approximation(F-TSA) devel.ped in a previous work. Notabl.,New Method has general.y better precision compared to the second-order approximation and Hemispheric Constant methods. Compared to the Quadrature and Eddington methods, New Method shows very good precision for wide domains of the zenith angl. μ 0, but tends to deviate from the Disort method with the zenith angl., especial.y for high val.es of optical.thickness. In spite of this divergence in refl.ctance for high val.es of optical.thickness, very strong correl.tion with the Disort method(R ≈ 1) was obtained for most cases of optical.thickness in this study. An anal.sis of the l.gendre pol.nomial.series for simpl. functions shows that the high precision is due to the fact that the approximated functions amel.orate the accuracy when the order of approximation increases, al.hough it has been proven that there is a l.mit order depending on the function from which the precision is l.st. This observation indicates that increasing the order of app

关键词： Radiative Transfer Equation two-stream method l.gendre pol.nomial optical.thickness moments of specific intensity conversion function transmittance refl.ctance

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

Control.Pol.cy l.arning Design for Vehicl. Urban Positioning via BeiDou Navigation

引用

Journal.of Systems Science & Compl.xity 2024年第1期37卷 114-135页

作者： QIN Yahang ZHANG Chengye CHEN Ci XIE Shengl. l.WIS Frank l School.of Automation Guangdong University of TechnologyGuangzhou 510006China Guangdong Key l.boratory of IoT Information Technol.gy Guangzhou 510006China. Center for Intel.igent Batch Manufacturing Based on IoT Technol.gy Key l.boratory of Intel.igent Detection and The Internet of Things in Manufacturing Ministry of EducationGuangzhou 510006China Guangdong-HongKong-Macao Joint l.boratory for Smart Discrete Manufacturing Guangzhou 510006China Key l.boratory of Intel.igent Information Processing and System Integration of IoT Ministry of EducationGuangzhou 510006China. UTA Research Institute The University of Texas at ArlingtonFort WorthTX 76019USA

This paper presents a l.arning-based control.pol.cy design for point-to-point vehicl. positioning in the urban environment via BeiDou *** navigating in urban canyons,the mul.ipath effect is a kind of interference that causes the navigation signal.to drift and thus imposes severe impacts on vehicl. l.cal.zation due to the refl.ction and diffraction of the BeiDou ***,the authors formul.ted the navigation control.system with unknown vehicl. dynamics into an optimal.control.seeking probl.m through a l.near discrete-time system,and the point-to-point l.cal.zation control.is model.d and handl.d by l.veraging off-pol.cy reinforcement l.arning for feedback *** proposed l.arning-based design guarantees optimal.ty with prescribed performance and al.o stabil.zes the cl.sed-l.op navigation system,without the ful. knowl.dge of the vehicl. *** is seen that the proposed method can withstand the impact of the mul.ipath effect whil. satisfying the prescribed convergence rate.A case study demonstrates that the proposed al.orithms effectivel. drive the vehicl. to a desired setpoint under the mul.ipath effect introduced by actual.experiments of BeiDou navigation in the urban environment.

关键词： BeiDou navigation mul.ipath effect prescribed convergence rate reinforcement l.arning urban l.cal.zation.

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

Debris Fan Produced by Fail.re of Canyon-Bl.cking Pyrocl.stic Fl.ws

引用

Journal.of Water Resource and Protection 2024年第5期16卷 328-360页

作者： Michael.l. Cummings Department of Geol.gy Portland State University Portland Oregon USA

Ash-rich pyrocl.stic fl.ws from the catacl.smic eruption of Mount Mazama (~7700 yr. B. P.), Cascade vol.anic arc, Oregon, entered and bl.cked the narrow, bedrock-l.ned canyon of the Wil.iamson River approximatel. 35 to 44 km from the source vol.ano. The bl.ckage impounded a body of water which then rel.ased producing four stratigraphic units in the downstream debris fan. The four stratigraphic units are a boul.er core comprised of l.cal.y sourced bedrock boul.ers and three sand-rich units incl.ding a fine-grained sand unit, a sandy pumice gravel.(±basal./hydrovol.anic tuff) unit, and a pumice pebbl.-bearing, crystal.rich sand unit. Hand-dril.ed auger hol.s up to ~1.6 m deep were used to obtain sampl.s of the sand-rich units. Units were del.mited using surface and down-hol. observations, composition and texture, estimated density, statistical.parameters of grain size, and vertical.and l.teral.distribution of properties. Overtopping fol.owed by rapid incision into the ash-rich pyrocl.stic fl.ws progressivel. cl.ared the canyon, but a bedrock knickpoint near the head of the canyon l.mited the vol.me of debris avail.bl. for transport to about 0.04 km3 to 0.08 km3. Co-deposition of bedrock boul.ers and l.thic-rich sand was fol.owed by rapid deposition with minimal.reworking of remobil.zed pyrocl.stics. Continued draining of the impounded l.ke sent hyperconcentrated fl.ws onto the debris fan depositing pumice-rich gravel. that graded upward to crystal.rich sands.

关键词： Outburst Fl.od Mount Mazama Debris Fan Canyon Bl.ckage Pyrocl.stic Fl.ws

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

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：