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micromorphology of Surface Crusts in the Knersvlakte,South Africa

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Journal of mountain Science 2009年第2期6卷 189-196页

作者： Sarah-Jane C.Fox Anthony J.mills rosa m.poch Department of Soil Science Stellenbosch UniversityStellenbosch South Africa Department of Environment and Soil Science University of LleidaRovira Roure 191 Lleida

Soils in the Knersvlakte are particularly prone to crusting and have lower inherent infiltrability than other soils across western southern Africa. micromorphological techniques were used to examine the structure and porosity of soil crusts in the Knersvlakte to ascertain why crusting is so intense in this region. Quantile regression using boundary lines was employed to examine the relationships between infiltrability and soil properties for all samples （n = 67）. This analysis showed that infiltrability is potentially maximal at low water- dispersible ＇clay plus silt＇ content and low silt content （r^2 = 0.72 and 0.64; respectively, n = 67）（Figure 2）. The strength of crusts, pH, EC, clay mineralogy, and water-dispersible clay, silt and ＇clay plus silt＇ content were compared, and a pore analysis using optical microscopy was undertaken on images of six soil thin sections （n = 6）（circular and parallel polarizers）. Pore analysis was further undertaken on five horizontal slices of equal dimensions taken through each soil thin section. The porosity samples with low infiltrability （〈 100 mm·hr^-1, n = 4） had greater crust strength, lower porosity （both total and in the least porous slice） and greater water-dispersible ＇day plus silt＇ and silt content than the porosity samples with high infiltrability （〉 100mm·hr^-1, n = 2）. The porosity samples with low infiltrability showed a trend of lower pH and greater water dispersible clay percentage. Porosity varied within the porosity samples due to the presence of dense clay/silt bands （〈 0.5 mm in width） with relatively few air vesicles. The porosity samples with horizontal slices of low porosity （but large numbers of air vesicles） had low infiltrability, while those without slices of low porosity （and relatively few air vesicles） had high infiltrability. We conclude that the intense crusting and resultant low infiltrability of soils in the Knersvlakte appears to be related to the formation of thin, dense clay/silt bands in the

关键词： Infiltrability optical microscopy porosity air vesicles

rationally designed synthesis of bright AgInS2/ZnS quantum dots with emission control

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Nano research 2020年第9期13卷 2438-2450页

作者： Jose X.Soares K.David Wegner David S.m.ribeiro Armindo melo Ines Hausler Joao L.m.Santos Ute resch-Genger LAQV-rEQUImTE Department of Chemical SciencesLaboratory of Applied ChemistryFaculty of PharmacyUniversity of PortoRua de Jorge Viterboferreira228Porto4050-313Portugal Federal Institute for materials research and Testing(BAm) Division BiophotonicsRichard-Willstaetter-Strasse 1112489 BerlinGermany LAQV-rEQUImTE Laboratorio de Bromatologia e HidrologiaDepartamento de Ciencias QutmicasFaculdade de Farmacia da Universidade do PortoRua de Jorge Viterboferreira228Porto4050-313Portugal Technische Universitat Berlin Institutfiir Optik und Atomare PhysikStrafie des 17.Juni 13510623 BerlinGermany

In the blossoming field of Cd-free semiconductor quantum dots(QDs),ternary Ⅰ-Ⅲ-VI QDs have received increasing attention due to the ease of the environmentally friendly synthesis of high-quality materials in water,their high photoluminescence(PL)quantum yields(QYs)in the red and near infrared(NIr)region,and their inherently low ***,their oxygen-insensitive long PL lifetimes of up to several hundreds of nanoseconds close a gap for applications exploiting the compound-specific parameter PL *** overcome the lack of reproducible synthetic methodologies and to enable a design-based control of their PL properties,we assessed and modelled the synthesis of high-quality mPA-capped AglnS2/ZnS(AlS/ZnS)*** refined parameters included reaction time,temperature,Ag:In ratio,S:In ratio,Zn:In ratio,mPA:ln ratio,and pH using a design-of-experiment *** for the optimization was provided by mathematical models developed for the application-relevant PL parameters,maximum PL wavelength,QY,and PL lifetime as well as the elemental composition in terms of Ag:ln:Zn *** these experimental data-based models,mPA:ln and Ag:ln ratios and pH values were identified as the most important synthesis parameters for PL control and an insight into the connection of these parameters could be ***,the experimental conditions to synthetize QDs with tunable emission and high QY were *** excellent agreement between the predicted and experimentally found PL features confirmed the reliability of our methodology for the rational design of high quality AlS/ZnS QDs with defined PL *** approach can be straightforwardly extended to other ternary and quaternary QDs and to doped QDs.

关键词： quantum dot core/shell nanoparticle silver indium sulfide microw ave-assisted synthesis design of experim ent photoluminescence

Experimental verification of ill-defined topologies and energy sinks in electromagnetic continua

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Advanced Photonics 2022年第3期4卷 97-104页

作者： David E.Fernandes ricardo A.m.Pereira Sylvain Lannebère Tiago A.morgado mário G.Silveirinha University of Coimbra Instituto de Telecomunicações and Department of Electrical EngineeringCoimbraPortugal University of Aveiro Instituto de TelecomunicaçõesDepartment of ElectronicsTelecommunications and InformaticsAveiroPortugal University of Lisbon Instituto Superior Técnico and Instituto de TelecomunicaçõesDepartment of Electrical EngineeringLisboaPortugal

.It is experimentally verified that nonreciprocal photonic systems with continuous translation symmetry may have an ill-defined *** topological classification of such systems is only feasible when the material response is regularized with a spatial-frequency *** experimentally demonstrate that adjoining a small air layer to the relevant material interface may effectively imitate an idealized spatial cutoff that suppresses the nonreciprocal response for short wavelengths and regularizes the ***,it is experimentally verified that nonreciprocal systems with an ill-defined topology may be used to abruptly halt the energy flow in a unidirectional waveguide due to the violation of the bulk-edge *** particular,we report the formation of an energy sink that absorbs the incoming electromagnetic waves with a large field enhancement at the singularity.

关键词： topological photonics nonreciprocity topological singularities bulk edge correspondence.

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灵丘硐沟银、锰矿床地质特征及成因

山西冶金 1999年第1期22卷 36-38页

作者：孟庆春马小兵冶金部第三地质勘查局地质勘查研究院

硐沟银锰矿床产于长城系高于庄组构造破碎带中,矿床规模中等,主矿体锰平均品位21.54％、银平均品位71.48g/t,是华北唯一优质银锰矿区。作者认为该矿床成矿作用经历了矿源层形成和燕山期成矿两个过程,属中低温热液矿床。

关键词：银、锰矿床地质特征硐沟