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Volume and surface effects on two-photonic and three-photonic processes in dry co-doped upconversion nanocrystals

Nano Research 2022年第3期15卷 2362-2373页

作者： Bettina Grauel Christian Würth Christian Homann Lisa Krukewitt Elina Andresen Janina Roik Sebastian Recknagel Markus Haase Ute Resch-Genger Federal Institute for Materials Research and Testing(BAM) Division 1.2 BiophotonicsRichard-Willstaetter-Str.1112489 BerlinGermany Federal Institute for Materials Research and Testing(BAM) Division 1.6 Inorganic Reference MaterialsRichard-Willstaetter-Str.1112489 BerlinGermany Institute of Chemistry of New Materials Department Biology/ChemistryUniversity OsnabrueckBarbarastr.749076 OsnabrueckGermany Department of Anesthesiology and Intensive Care Medicine University Medical Center RostockSchillingallee 3518057 RostockGermany

Despite considerable advances in synthesizing high-quality core/shell upconversion(UC)nanocrystals(NC;UCNC)and UCNC photophysics,the application of near-infrared(NIR)-excitable lanthanide-doped UCNC in the life and material sciences is still hampered by the relatively low upconversion luminescence(UCL)of UCNC of small size or thin protecting *** obtain deeper insights into energy transfer and surface quenching processes involving Yb^(3+) and Er^(3+) ions,we examined energy loss processes in differently sized solid core NaYF_(4) nanocrystals doped with either Yb^(3+)(YbNC;20%Yb^(3+))or Er^(3+)(ErNC;2%Er^(3+))and co-doped with Yb^(3+) and Er^(3+)(YbErNC;20%Yb^(3+) and 2%Er^(3+))without a surface protection shell and coated with a thin and a thick NaYF_(4) shell in comparison to single and co-doped bulk *** studies at 375 nm excitation demonstrate back-energy transfer(BET)from the ^(4)G_(11/2) state of Er^(3+) to the ^(2)F_(5/2) state of Yb^(3+),through which the red Er^(3+) ^(4)F_(9/2) state is efficiently *** power density(P)-dependent steady state and time-resolved photoluminescence measurements at different excitation and emission wavelengths enable to separate surface-related and volume-related effects for two-photonic and three-photonic processes involved in UCL and indicate a different influence of surface passivation on the green and red Er3+*** intensity and lifetime of the latter respond particularly to an increase in volume of the active UCNC *** provide a three-dimensional random walk model to describe these effects that can be used in the future to predict the UCL behavior of UCNC.

关键词： upconversion luminescence core/shell nanoparticles dopant concentration lifetime volume effect surface quenching

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NIBU: a new approach to representing and analysing interior utility networks within 3D geo-information systems

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International Journal of Digital Earth 2012年第1期5卷 22-42页

作者： Ihab Hamzi Hijazi Manfred Ehlers Sisi Zlatanova Institute for Geoinformatics and Remote SensingIGF University of OsnabrueckOsnabrueckGermany OTB Research Institute for HousingUrban and Mobility StudiesDelft University of TechnologyDelftThe Netherlands

Facility management departments’responsibilities include monitoring and maintenance of building infrastructure,such as water,gas or *** often these tasks are completed using paper maps,which make integrated analysis of networks *** to consider interior network structure and provide semantic and connectivity information supporting the required analysis operations are thus *** paper presents an approach relying on Building Information Model(BIM)as a data source for obtaining information about interior *** semantic and connectivity information of BIM is mapped onto a new model called Network for Interior Building Utilities(NIBU).NIBU is based on the semantic categorisation of utilities,and the spatial functions that have to be *** scenarios(‘maintenance operation’,‘emergency response’and‘inspection operation’)are developed to test the proposed *** model and its functions are implemented in spatial *** model is populated directly from a BIM server applying an Industrial Foundation Class(IFC)parser developed *** analysis functions are implemented to support spatial operations:trace upstream,trace downstream,find ancestors,find source and find *** investigation proves that BIM provides both the required semantics and attributes,and connectivity information that can facilitate analysis of interior utility *** provides a simple yet flexible way to manage interior network information,which can be integrated into Digital Earth.

关键词： building information model(BIM) building service system graph spatial DBMS utility network industrial foundation class(IFC)

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Geoinformatics and digital earth initiatives:a German perspective

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International Journal of Digital Earth 2008年第1期1卷 17-30,I0002页

作者： M.Ehlers Institute for Geoinformatics and Remote Sensing University of OsnabrueckSeminarstr.19 abD-49074 OsnabrueckGermany

This paper discusses the role of Geoinformatics as a new scientific discipline designed for handling of geospatial *** on the scientific background of the people involved in shaping the emerging discipline,emphasis may be placed on different aspects of *** and developments may address geoscientific,spatial planning,or computer science related *** scientific field of Geoinformatics encompasses the acquisition and storing of geospatial data,the modelling and presentation of spatial information,geoscientific analyses and spatial planning,and the development of algorithms and geospatial database *** is the position of the author that these tools from Geoinformatics are necessary to bridge the gap between Digital Earth models and the real world with its real-world problems(‘connecting through location’).It is,however,crucial that Geoinformatics represents a coherent integrated approach to the acquisition,storage,analysis,modeling,presentation,and dissemination of geo-processes and not a patchwork solution of unconnected fields of *** is as such not a part of Geography,Surveying,or Computer Science,but a new self-contained scientific *** current paper highlights international and national trends of the discipline and presents a number of Geoinformatics *** research and teaching activities of the newly formed Institute for Geoinformatics and Remote Sensing(IGF)at the university of osnabrueck serve as an example for these *** these developments have lead to the long overdue formation of a scientific‘Society for Geoinformatics’(German:Gesellschaft fu¨r Geoinformatik-GfGI)in Germany.

关键词： geoinformatics digital earth modeling position paper emerging scientific discipline academic programmes

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Optical Waveguide Formation in LiNbO_(3) by the 2.6 MeV Nickel Ions Implantation

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Chinese Physics Letters 2001年第2期18卷 242-244页

作者：胡卉陈峰卢霏张建华刘吉田王克明时伯荣沈定予王雪梅 Department of Physics Shandong UniversityJi’nan 250100 Department of Physics University of OsnabrueckD-49069OsnabrueckGermany MOE Key Laboratory of Heavy Ion Physics Peking UniversityBeijing 100871

The optical waveguide was formed on an LiNbO_(3) substrate by 2.6 MeV nickel ions implantation to the dose of 9×10^(14) ions/cm^(2).Five dark modes were observed by the prism coupling *** refractive index profile was obtained by using the reflectivity calculation method.A large index decrease was found in the guiding region and in the optical barrier,which is somewhat different from that of the LiNbO_(3) waveguide formed by the MeV He+*** position of the optical barrier is deeper than that of the damage peak calculated by TRIM'90(Transport of Ions in Matter)*** crystal lattice damage in the guiding region caused by the Ni+ion implantation was analysed by the Rutherford backscattering/channelling technique.

关键词： technique waveguide implantation

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The Plastid-Localized NAD-Dependent Malate Dehydrogenase Is Crucial for Energy Homeostasis in Developing Arabidopsis thaliana Seeds

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Molecular Plant 2014年第1期7卷 170-186页

作者： Jennifer Selinski Nicolas Konig Benedikt Wellmeyer Guy T. Hanke Vera Linke H. Ekkehard Neuhaus Renate Scheibe Department of Plant Physiology FB 5 University of Osnabrueck D-49069 Osnabrueck Germany Department of Plant Physiology FB Biology TU Kaiserslautern D-67663 Kaiserslautern Germany

In the absence of photosynthesis, ATP is imported into chloroplasts and non-green plastids by ATP/ADP transporters or formed during glycolysis, the latter requiring continuous regeneration of NAD＋, supplied by the plastidial isoform of NAD-MDH. During screening for T-DNA insertion mutants in the plNAD-MDH gene of Arabidopsis, only heterozygous plants could be isolated and homozygous knockout mutants grew only after complementation. These heterozygous plants show higher transcript levels of an alternative NAD＋-regenerating enzyme, NADH-GOGAT, and, remarkably, improved growth when ammonium is the sole N-source. In situ hybridization and GUS-histochemical stain- ing revealed that plNAD-MDH was particularly abundant in male and female gametophytes. Knockout plNAD-MDH pollen exhibit impaired tube growth in vitro, which can be overcome by adding the substrates of NADH-GOGAT. In vivo, knockout pollen is able to fertilize the egg cell. Young siliques of selfed heterozygous plants contain both green and white seeds corresponding to wild-type/heterozygous （green） and homozygous knockout mutants （white） in a （1：2）：1 ratio. Embryos of the homozygous knockout seeds only reached the globular stage, did not green, and developed to tiny wrinkled seeds. Complementation with the gene under the native promoter rescued this defect, and all seeds developed as wild-type. This suggests that a blocked major physiological process in plNAD-MDH mutants stops both embryo and endosperm development, thus avoiding assimilate investment in compromised offspring.

关键词： malate valve plastidial glycolysis ammonium assimilation NADH-GOGAT redox-balance embryo lethality.

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LiYF_(4):Yb/LiYF_(4) and LiYF_(4):Yb,Er/LiYF_(4) core/shell nanocrystals with luminescence decay times similar to YLF laser crystals and the upconversion quantum yield of the Yb,Er doped nanocrystals

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Nano Research 2021年第3期14卷 797-806页

作者： Frederike Carl Leonie Birk Bettina Grauel Monica Pons Christian Würth Ute Resch-Genger Markus Haase Institute of Chemistry of New Materials Department Biology/ChemistryUniversity OsnabrueckBarbarastr.749076OsnabrueckGermany Division 1.2 Biophotonics Federal Institute for Materials Research and Testing(BAM)Richard-Willstaetter-Str.1112489BerlinGermany

We developed a procedure to prepare luminescent LiYF_(4):Yb/LiYF_(4) and LiYF_(4):Yb,Er/LiYF_(4) core/shell nanocrystals with a size of approximately 40 nm revealing luminescence decay times of the dopant ions that approach those of high-quality laser crystals of LiYF_(4):Yb(Yb:YLF)and LiYF_(4):Yb,Er(Yb,Er:YLF)with identical doping *** the luminescence decay times of Yb^(3+)and Er^(3+)are known to be very sensitive to the presence of quenchers,the long decay times of the core/shell nanocrystals indicate a very low number of defects in the core particles and at the core/shell *** improvement in the performance was achieved by introducing two important modifications in the commonly used oleic acid based ***,the shell was prepared via a newly developed method characterized by a very low nucleation rate for particles of pure LiYF_(4) shell ***,anhydrous acetates were used as precursors and additional drying steps were applied to reduce the incorporation of OH−in the crystal lattice,known to quench the emission of Yb^(3+)*** power density(P)-dependent absolute measurements of the upconversion luminescence quantum yield(ΦUC)of LiYF_(4):Yb,Er/LiYF_(4) core/shell particles reveal a maximum value of 1.25%at P of 180 W·cm^(−2).Although lower than the values reported for NaYF4:18%Yb,2%Er core/shell nanocrystals with comparable sizes,theseΦUC values are the highest reported so far for LiYF_(4):18%Yb,2%Er/LiYF_(4) nanocrystals without additional *** improvements may nevertheless be possible by optimizing the dopant concentrations in the LiYF_(4) nanocrystals.

关键词： nanocrystal decay time luminescence LiYF_(4) quantum yield upconversion

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Induction of the AOX1D Isoform of Alternative Oxidase in A. thaliana T-DNA Insertion Lines Lacking Isoform AOX1A Is Insufficient to Optimize Photosynthesis when Treated with Antimycin A

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Molecular Plant 2009年第2期2卷 284-297页

作者： Inga Strodtkotter Kollipara Padmasree Challabathula Dinakar Birgit Speth Pamela S. Niazi Joanna Wojtera Ingo Voss Phuc Thi Do Adriano Nunes-Nesi Alisdair R. Fernie Vera Linke Agepati S. Raghavendra Renate Scheibe Department of Plant Physiology FBS University of Osnabrueck 49069 Osnabrueck Germany Department of Plant Sciences School of Life Sciences University of Hyderabad Hyderabad 500 046 India Max Planck Institute for Molecular Plant Physiology Am Muhlenberg-1 14476 Potsdam-Golm Germany

Plant respiration is characterized by two pathways for electron transfer to O2, namely the cytochrome pathway （CP） that is linked to ATP production, and the alternative pathway （AP）, where electrons from ubiquinol are directly transferred to O2 via an alternative oxidase （AOX） without concomitant ATP production. This latter pathway is well suited to dispose of excess electrons in the light, leading to optimized photosynthetic performance. We have characterized T- DNA-insertion mutant lines of Arabidopsis thaliana that do not express the major isoform, AOXIA. In standard growth conditions, these plants did not show any phenotype, but restriction of electron flow through CP by antimycin A, which induces AOXIA expression in the wild-type, led to an increased expression of AOXID in leaves of the aoxla-knockout mutant. Despite the increased presence of the AOX1D isoform in the mutant, antimycin A caused inhibition of photosyn- thesis, increased ROS, and ultimately resulted in amplified membrane leakage and necrosis when compared to the wild- type, which was only marginally affected by the inhibitor. It thus appears that AOX1 D was unable to fully compensate for the loss of AOXIA when electron flow via the CP is restricted. A combination of inhibition studies, coupled to metabolite profiling and targeted expression analysis of the P-protein of glycine decarboxylase complex （GDC）, suggests that the aoxla mutants attempt to increase their capacity for photorespiration. However, given their deficiency, it is intriguing that increase in expression neither of AOX1D nor of GDC could fully compensate for the lack of AOXIA to optimize pho- tosynthesis when treated with antimycin A. We suggest that the aoxla mutants can further be used to substantiate the current models concerning the influence of mitochondrial redox on photosynthetic performance and gene expression.

关键词： abiotic/environmental stress acclimation--physiological alternative electron transport photorespiration photosynthesis mitochondria T-DNA insertion line.

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A review of remote sensing applications for oil palm studies

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Geo-Spatial Information Science 2017年第2期20卷 184-200页

作者： Khai Loong Chong Kasturi Devi Kanniah Christine Pohl Kian Pang Tan Faculty of Geoinformation and Real Estate Universiti Teknologi MalaysiaJohor BahruMalaysia Centre for Environmental Sustainability and Water Security(IPASA) Research Institute for Sustainable Environment(RISE)Universiti Teknologi MalaysiaJohor BahruMalaysia Institute of Computer Science University of OsnabrueckOsnabrueckGermany

Oil palm becomes an increasingly important source of vegetable oil for its production exceeds soybean,sunflower,and *** growth of the oil palm industry causes degradation to the environment,especially when the expansion of plantations goes *** sensing is a useful tool to monitor the development of oil palm *** order to promote the use of remote sensing in the oil palm industry to support their drive for sustainability,this paper provides an understanding toward the use of remote sensing and its applications to oil palm plantation *** addition,the existing knowledge gaps are identified and recommendations for further research are given.

关键词： Oil palm remote sensing monitoring agriculture mapping sustainability

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NIBU:An Integrated Framework for Representing the Relation Among Building Structure and Interior Utilities in Micro-Scale Environment

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Geo-Spatial Information Science 2011年第2期14卷 98-108页

作者： Ihab HIJAZI Sisi ZLATANOVA Manfred EHLERS Institute for Geoinformatics and Remote Sensing (IGF) University of Osnabrueck OTB Research Institute for HousingUrban and Mobility Studies Delft University of Technology

This paper describes a framework for modeling interdependencies between different network systems and building *** provides an approach for the integrated analysis of interior building utilities by describing a framework to model and simulate infrastructure interdependencies and their complex *** is a graph-based spatial model that can support use cases such as providing the location and specifications of interior utilities to a technician who wants to perform a maintenance *** location could be needed for maintenance or replacement,or to investigate the result of damage to the building structure on another utility network,or to estimate the effect of different maintenance operations in different locations along utilities service *** model accounts for two important aspects:first,the relationship between interior utilities and building elements or spaces and second,the building hierarchy structure to which the utilities network is related.A proper hierarchy of the building is developed which supports the generation of human-oriented descriptions of interior utilities,where a method for partitions of large building element and spaces as well as a method to reference a network element to another building are *** connection of the different utilities network systems and buildings are generated using joints,which are based on a containment *** example is presented which shows the effectiveness of this approach for supporting maintenance operations,as well as the independences between the maintenance operation location and the other network *** paper presents the data model and explains the links with current 3D building model standards.

关键词：大楼信息模型(BIM ) 大楼服务系统实用程序网络图城市模型

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The Relevance of Web Mapping Infrastructures in a Web Portal for Desktop and Mobile Devices: A Case Study

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Journal of Geographic Information System 2012年第6期4卷 514-520页

作者： Kai Behncke Manfred Ehlers Creativista Solutions osnabrueck Germany Institute for Geoinformatics and Remote Sensing University of Osnabrueck Osnabrueck Germany

There exists a lack of detailed empirical studies to assess the relevance of WebMapping applications. Despite this fact, it is quite common to note that importance and influence of WebMapping applications have increased over the last years. This paper presents the result of an empirical study to analyze the importance of a Desktop-WebMapping application for a gastronomic web 2.0 portal for the city of Osnabrück. An exploratory focus is to evaluate how often geospatial information (in a broader information context) from this web portal is used and how important the WebMapping applications are for the users of the web portal. Furthermore, it is evaluated which WebMapping functions (e.g. routing, queries, printing) are of relevance to the users and what the order of importance is for the provided functions. To-date, just a few mobile WebMapping applications for handheld devices exist. Consequently, for OsnaGo we developed a mobile WebMapping component that can be used with mobile phones, PDAs and other handheld devices to access the web portal (http://***). Development and user based evaluation is presented in this paper.

关键词： WebMapping WebGIS Open Source Mobile GIS

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