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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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金属标准物质中杂质的辉光放电质谱法溯源分析

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冶金分析 2012年第2期32卷 6-10页

作者： recknagel sebastian KIPPHARDT Heinrich LANGE Britta HOPPE Marion 德联邦材料测试研究院

标准物质定值分析的溯源性要求比常规分析高很多。在常规分析中,有证标准物质(CRM)可用于校准以及建立可溯源性。尽管与标准物质生产和认定相关的ISO导则并没有十分明确地提到校准,但众多标准物质生产者在定值分析时却不接受基准标准物... 详细信息

标准物质定值分析的溯源性要求比常规分析高很多。在常规分析中,有证标准物质(CRM)可用于校准以及建立可溯源性。尽管与标准物质生产和认定相关的ISO导则并没有十分明确地提到校准,但众多标准物质生产者在定值分析时却不接受基准标准物质用于校准。这些要求制约了标准物质定值方法的使用,因为这些方法可以采用已知高纯度的标准物质、化学计量法及已知高纯度标准物质的混合物进行校准。有效的固体取样技术,例如通常使用的块状标准物质进行校准的辉光放电质谱法(GD-MS)或火花源发射光谱法(spark-OES),似乎不太适合定值分析。尤其是固体样品中痕量元素分析测定的有力工具辉光放电质谱法,除金属杂质外,使用特定气体混合物,这种方法也可以分析相关的非金属杂质如硫和磷。我们开发了一种可以使用已知高纯度的标准物质混合物和化学计量法的校准方法,这种校准方法同样可用于辉光放电质谱法。与溶液中基体匹配技术类似,此校准方法基于掺杂的粉末压片。本文还结合铜和钢标准物质的定值分析结果进行了陈述。

关键词：标准物质溯源性辉光放电质谱法铜钢铁

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Certified Reference Material for Determination of Total Cyanide in Soil[BAM-U116/CGL306]

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Journal of Environmental Science and Engineering(B) 2018年第4期7卷 149-161页

作者： sebastian recknagel Holger Scharf Batzorig Lkhagvasuren Oyuntungalag Urjin Juergen Rausch Department of Analytical Chemistry Federal Institute for Materials Research and TestingBerlin 12205Germany Department of Reference Material and Proficiency Testing Section Central Geological LaboratoryUlaanbaatar 18080Mongolia Department of Groundwater Resources-Quality and Dynamics Federal Institute for Geosciences and Natural ResourcesHannover 30655Germany

CRM(Certified Reference Material)BAM-U116/CGL306“Cyanide in soil”was produced within a framework of cooperation between CGL(Central Geological Laboratory)of Mongolia and Federal Institute for Materials Research and Testing(BAM)of Germany in *** CRM BAM-U116/CGL306 represents a mixture of a sandy soil collected from a contaminated former gasworks area in the Berlin region(Germany)and an unpolluted sandy soil from Nalaikh region(Mongolia).The bulk candidate material for this reference material was prepared at CGL CRM Laboratory exclusively destined to the preparation of reference materials and equipped with modern technical ***,stability and shelf life were studied in full compliance with ISO Guide *** CRM was evaluated as sufficiently *** evaluation of certification analysis was software packages SoftCRM and ProLab *** value of total cyanide of the CRM is 12.0 mg/kg and expanded uncertainty was assigned as 0.8 mg/*** intended purpose of this material is the verification of analytical results obtained for the mass fraction of total cyanide in soils and soil-like materials applying the standardized procedure ISO 11262:*** any reference material,it can also be used for routine performance checks(quality control charts)or validation studies.

关键词： CRM cyanide in soil total cyanide

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