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Speciation in nanosecond laser ablation of zinc in water

Science China(Physics,Mechanics & Astronomy) 2022年第7期65卷 90-98页

作者： Stefan Reich Yannis Klügl Anna Ziefuss RenéStreubel jorg Gottlicher Anton Plech Institute for Photon Science and Synchrotron Radiation Karlsruhe Institute of TechnologyKarlsruhe D-76021Germany Department of Technical ChemistryⅠand Center for Nanointegration Duisburg-Essen University of Duisburg-EssenEssen D-45141Germany Fraunhofer Institute for High-Speed Dynamics Ernst-Mach-Institute(EMI)Freiburg 79104Germany

In situ experimental methods have been applied to resolve mass flow and chemical speciation in the pulsed laser ablation of zinc in water. The chemical speciation has been resolved by time-resolved μ-X-ray absorption spectroscopy and mapped onto the macroscopic mass flow during material ejection from the metallic target and bubble dynamics of evaporated water. Large particles and agglomerates have been detected via dark-field X-ray imaging with a Shack-Hartmann sensor. The characteristic of the dynamics is that the vapor bubble is nearly homogeneously filled with ablated material. This persists during bubble collapse,which means that the ablated particles are captured and retracted towards the target. Limited mass escape is indicated by the X-ray absorption signal. Importantly, the near-edge structure at the Zn-K;transition delivers information on the chemical state of the ejected material. It clearly confirms that oxidation is not present within the bubble phase and the following sub-millisecond time scale. The oxidation proceeds on Zn nanoparticles in suspension on a second to minute course. Within the first microseconds,a Zn atom phase is detected that resembles Zn vapor. The addition of either reductive NaBH;or oxidative HAuCl;to the water phase influences the quantity of the atom contribution moderately, but does not influence the initial atom phase. Such behavior must be understood in terms of the nanosecond pulse excitation. After ejected material and a plasma is formed within the pulse duration of 7 ns the laser is able to further heat the ejecta and transform it partly into vapor. Correspondingly, the coupling of energy into the ablation zone as followed by plasma intensity and bubble size follows a threshold behavior as a function of laser fluence, marking the onset of laser-plasma heating. The reaction conditions inside the bubble are probably reductive due to the concomitant formation of excess hydrogen.

关键词： laser ablation in liquids elemental speciation X-ray absorption spectroscopy oxidation zinc oxide nanoparticles

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Adsorption/Desorption of Low-density Lipoprotein on a Heparinized Surface of Gold Sensors

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Chemical Research in Chinese Universities 2012年第2期28卷 323-328页

作者： LAN Ping JI Jing HUANG Xiao-Jun GUDURU Deepak GROTH Thomas VIENKEN jorg D1NG Hui College of Materials and Textiles Jiaxing UniversityJiaxing 314001P.R.China Key Laboratory of Macromolecular Synthesis and Functionalization Ministry of EducationDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027P.R.China Biomedical Materials Group Department of Pharmaceutics and BiopharmaeeuticsInstitute of PharmacyMartin Luther University Halle-WittenbergHalle(Saale)06120Germany Fresenius Medical Care of Deutschland GmbH BioSciences DepartmentBad Homburg 61352Germany College of Mathematics Physics and Information Engineering Jiaxing UniversityJiaxing 314001P.R.China

Heparin has been considered to be a potentially useful ligand for low-density lipoprotein（LDL） detection and analysis in a clinical *** order to construct an affinity surface for preferential adsorption of LDL,heparin-modified gold surface（GS-Hep） was fabricated by a self-assembling method and hydrophobic-modified gold surfaces（GS-Hydro） was used as a *** morphologies of the modified gold surfaces were investigated by atomic force microscopy（AFM） and the quantity of heparin bound to gold surface was assayed by the toluidine blue（TB） colorimetric *** contact angles were determined to investigate wettability on GS-Hep and *** plasmon resonance（SPR） technique was used subsequently to detect the selective binding of LDL with *** the investigation on the effect of pH on LDL adsorption suggests that lower pH lead to higher quantities of LDL adsorption on *** with GS-Hydro,GS-Hep is selective for LDL from both single and binary protein ***,adsorbed LDL on GS-Hep could be washed off by injecting elution solution,such as NaCl solution,for the purpose of the regeneration of GS-Hep for further LDL adsorption.

关键词： Adsorption/desorption Low-density lipoprotein(LDL) Heparinized surface Surface plasmon resonance

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When Lotus Leaves Prevent Metal from Melting一Biomimetic Surfaces for High Temperature Applications

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Journal of Bionic Engineering 2019年第2期16卷 281-290页

作者： Wilfried Konrad jorg Adam Siegfried Konietzko Christoph Neinhuis Technical University of Dresden Institute of BotanyZellescher Weg 20bD-01062 Dresden Germany VDEh-Betriebsforschungsinstitut GmbH Sohnstrafie 6540237 DusseldorfGermany Lebronze Alloys Germany-Hundt&Weber GmbH、Birlenbacher Strafie 1 57078 SiegenGermany CON-RE A Consulting&RealizationGrafschafter Strafie 1347199 DuisburgGermany

Functional properties of biological surfaces have gained increasing interest in the last two decades,especially with regard to wetting and ***,biological surfaces of arthropods(Collembola)and plants(sacred Lotus)served as models for the principle design of high temperature resistant surfaces used in blast furnaces to prevent tuyeres from *** are double-walled,watercooled pipes supplying the blast furnace with hot air to keep the reduction and melting process *** failure is mainly caused by melting of the wall after direct contact with liquid iron,resulting in the partial shut down of the blast furnace and huge energy *** a new approach to avoid tuyere failure we developed a new type of tuyere surface with(i)defined cone shaped indentations and(ii)a heat resistant zirconium/corundum coating with"ferrophobic”properties *** forms with liquid iron of 1500°C a contact angle exceeding 130°.Theoretical considerations indicate that liquid iron infiltrates these indentations only partially if this contact angle and the aperture angle of the cone satisfy an inequality *** heat conductivity of the remaining gas trapped inside the cones is by five orders of magnitude lower than in copper,the overall heat flow into the tuyere is substantially reduced and the outer walls are much less prone to melting.

关键词： tuyere blast furnace biomimetics liquid iron heat flow

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Rarity among benign gastric tumors: Plexiform fibromyxoma-Report of two cases

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World Journal of Gastroenterology 2017年第31期23卷 5817-5822页

作者： Kinga Szurian Holger Till Eva Amerstorfer Nicole Hinteregger Hans-jorg Mischinger Bernadette Liegl-Atzwanger Iva Brcic Institute of Pathology Medical University of Graz Department of Paediatric and Adolescent Surgery Medical University of Graz Department of Radiology Division of NeuroradiologyVascular and Interventional RadiologyMedical University of Graz Department of Surgery Medical University of Graz

Plexiform fibromyxoma is a very rare mesenchymal tumor of the stomach, found almost exclusively in the antrum/pylorus region. The most common presenting symptoms are anemia, hematemesis, nausea and unintentional weight loss, without sex or age predilection. We describe here two cases of plexiform fibromyxoma, involving a 16-year-old female and a 34-year-old male. Both patients underwent complete resection(R0) by distal gastrectomy and retrocolic gastrojejunostomy(according to Billroth 2); for both, the postoperative course was uneventful. Histology showed multiple intramural and subserosal nodules with characteristic plexiform growth, featuring bland spindle cells situated in an abundant myxoid stroma with low mitotic activity. Immunohistochemistry showed α-smooth muscle actin-positive spindle cells, focal positivity for CD10, and negative staining for KIT, DOG1, CD34, S100, β-catenin, STAT-6 and anaplastic lymphoma kinase. One of the cases showed focal positivity for h-caldesmon and desmin. Upon followup, no sign of disease was found. In the differential diagnosis of plexiform fibromyxoma, it is important to exclude the more common gastrointestinal stromal tumors as they have greater potential for aggressivebehavior. Other lesions, like neuronal and vascular tumors, inflammatory fibroid polyps, abdominal desmoid-type fibromatosis, solitary fibrous tumors and smooth muscle tumors, must also be excluded.

关键词： Plexiform fibromyxoma Plexiform angiomyxoid myofibroblastic tumor Gastrointestinal stromal tumor Stomach Benign gastric tumor

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Nanoporous magnesium

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Nano Research 2018年第12期11卷 6428-6435页

作者： Ilya Vladimirovich Okulov Sviatlana V.Lamaka Takeshi Wada Kunio Yubuta Mikhail L.Zheludkevich jorg Weissmuller Jurgen Markmann Hidemi Kato Institute for Materials Research Tohoku UniversityKatahira 2-1-1Sendai980-8577Japan Institute of Materials Research Materials MechanicsHelmholtz-Zentrum Geesthacht21502GeesthachtGermany MagiC-Magnesium Innovation Centre Helmholtz-Zentrum Geesthacht21502GeesthachtGermany Faculty of Engineering University of Kiel24118KielGermany Institute of Materials Physics and Technology Hamburg University of Technology21073HamburgGermany

In this study, we present freestanding nanoporous magnesium as a novel lightweight material with high potential for structural and functional applications. Thus far, the high reactivity of Mg with oxygen and aqueous media prevented the fabrication of nanoporous Mg. First, in order to synthesize nanoporous Mg, we fabricated a bicontinuous nanocomposite consisting of interpenetrating Mg and non-Mg phases by liquid metal dealloying. The non-Mg phases in the nanocomposite protect Mg against corrosion. Second, we etched the non-Mg phases from the nanocomposite, leaving nanoporous Mg, using HF solution. This process is advantageous because the nanoporous Mg was passivated by a MgF2 layer during the etching. Our approach is very flexible, and we demonstrate that versatile microstructures of the nanoporous Mg—e.g., nanoscale bicontinuous network, hierarchical, or plate-like structures—can be designed for the given needs. More importantly, these nanoporous Mg samples can readily be exposed to air without being harmed by corrosion.

关键词： dealloying nanoporous magnesium

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Artificial gauge field switching using orbital angular momentum modes in optical waveguides

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Light(Science & Applications) 2020年第1期9卷 577-583页

作者： Christina jorg Gerard Queralto Mark Kremer Gerard Pelegri Julian Schulz Alexander Szameit Georg von Freymann Jordi Mompartand Veronica Ahufinger Physics Department and Research Center OPTIMAS Technische Universitat Kaiserslautern67663 KaiserslauternGermany Departament de Fisica Universitat Auto’noma de BarcelonaE-08193 BellaterraSpain Institut fur Physik Universitat RostockAlbert-Einstein-StraBe 2318059 RostockGermany Department of Physics and SUPA University of StrathclydeGlasgow G40NGUK Fraunhofer Institute for Industrial Mathematics ITWM 67663 KaiserslauternGermany

The discovery of artificial gauge fields controlling the dynamics of uncharged particles that otherwise elude the influence of standard electromagnetic fields has revolutionised the field of quantum ***,developing new techniques to induce these fields is essential to boost quantum simulation of photonic ***,we experimentally demonstrate the generation of an artificial gauge field in a photonic lattice by modifying the topological charge of a light beam,overcoming the need to modify the geometry along the evolution or impose external *** particular,we show that an effective magnetic flux naturally appears when a light beam carrying orbital angular momentum is injected into a waveguide lattice with a diamond chain *** demonstrate the existence of this flux,we measure an effect that derives solely from the presence of a magnetic flux,the Aharonov-Bohm caging effect,which is a localisation phenomenon of wavepackets due to destructive ***,we prove the possibility of switching on and off artificial gauge fields just by changing the topological charge of the input state,paving the way to accessing different topological regimes in a single structure,which represents an important step forward for optical quantum simulation.

关键词： gauge momentum orbital

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Uganda

Uganda

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作者： edited by jorg Wiegratz Giuliano Martiniello Elisa Greco.

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High-yield synthesis and liquid-exfoliation of two- dimensional belt-like hafnium disulphide

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Nano Research 2018年第1期11卷 343-353页

作者： Harneet Kaur Sandeep Yadav Avanish K. Srivastava Nidhi Singh Shyama Rath jorg J. Schneider Om P. Sinha Ritu Srivastava National Physical Laboratory Council of Scientific and Industrial Research Dr. K. S. Krishnan Road New Delhi I I O012 India Academy of Scientific and Innovative Research NPL New Delhi 110012 India Technische Universitat Darmstadt Eduard-ZintMnstitut f~r Anorganische und Physikalische Chemie 12 105 117 Alarich-Weiss-Str 12 64287 Darmstadt Germany DepartmentofPhysics andAstrophysics University of Delhi Delhi 110007 India Amity Institute of Nanotechnology Amity University UP Sector 125 Noida Uttar Pradesh 201313 India

Producing environmentally stable monolayers and few-layers of hafnium disulphide （HfS2） with a high yield to reveal its unlocked electronic and optoelectronic applications is still a challenge. HfS2 is a layered two-dimensional material of group-IV transition metal dichalcogenides. For the first time, we demonstrate a simple and cost-effective method to grow layered belt-like nanocrystals of HfS2 with a notably large interlayer spacing followed by their chemical exfoliation. Various microscopic and spectroscopic techniques confirm that these as-grown crystals exfoliate into single or multiple layers in a few minutes using solvent assisted ultrasonification method in N-cyclohexyl-2- pyrrolidone. The exfoliated nanosheets of HfS2 exhibit an indirect bandgap of 1.3 eV with high stability against surface degradation. Furthermore, we demonstrate that these nanosheets hold potential for electronic applications by fabricating a field-effect transistor based on few-layered HfS2, exhibiting a field-effect mobility of 0.95 cm2/（V.s） with a high on/off current modulation ratio of 10,000 in ambient conditions. The method is scalable and has a potential significance for both academic and industrial purposes.

关键词： two-dimensionalmaterials hafnium disulphide nano-crystals liquid-phase exfoliation environment-stabili~ field-effect transistor

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Energy-Minimizing Curve Fitting for High-Order Surface Mesh Generation

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Applied Mathematics 2014年第21期5卷 3318-3327页

作者： Karsten Bock jorg Stiller Institute of Fluid Mechanics(ISM) Technische Universitat DresdenDresdenGermany

We investigate different techniques for fitting Bézier curves to surfaces in context of high-order curvilinear mesh generation. Starting from distance-based least-squares fitting we develop an incremental algorithm, which incorporates approximations of stretch and bending energy. In the process, the algorithm reduces the energy weight in favor of accuracy, leading to an optimized set of sampling points. This energy-minimizing fitting strategy is applied to analytically defined as well as triangulated surfaces. The results confirm that the proposed method straightens and shortens the curves efficiently. Moreover the method preserves the accuracy and convergence behavior of distance-based fitting. Preliminary application to surface mesh generation shows a remarkable improvement of patch quality in high curvature regions.

关键词： Curvilinear Mesh Generation High-Order Methods Bézier Curves Curve Fitting Energy Minimization

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Use of a dietary exposure system for screening of insecticidal compounds for their toxicity to the planthopper Laodelphax striatellus

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Insect Science 2014年第5期21卷 667-675页

作者： Zeng-Xia Wang Ke-Jian Lin jorg Romeis Yong-Lei Liu Ze-Wen Liu Yun-He Li Yu-Fa Peng State Key Laboratory for Biology of Plant Diseases and Insect Pests Institute of Plant Protection Chinese Academy of Agricultural Sciences Beijing Nanjing Agricultural University Nanjing China Agroscope Reckenholz-Tanikon Research Station ART ZurichSwitzerland

We developed a dietary exposure assay for screening insecticidal compounds for their toxicity and for assessing the side effects of insecticidal proteins produced by genetically engineered （GE） plants on the planthopper Laodelphax striatellus Fallen. The fitness bioassay confirmed that the diet fulfills the requirements to be used in the dietary exposure system. To validate the efficacy of the dietary exposure system, nymphs of L. striatellus were fed diets treated with different concentrations of an inorganic stomach poison, potassium arsenate （PA）, or a cysteine protease inhibitor, E-64. The results showed that with increasing concentrations of E-64, the larval development time was prolonged, the adult weight was reduced and the survival rate of L. striatellus was decreased. Similarly the survival rates of L. striatellus consistently decreased with increasing PA content in the diet. The data indicate that the dietary exposure assay is able to detect the effects of insecticidal compounds on L. striatellus. Subsequently, this assay was successfully used for assessing the potential toxicity of Cry2Aa. The results showed that L. striatellus larvae were not negatively affected when fed the artificial diet containing purified Cry2Aa at 300 μg/g diet. In the assay, the stability and bioactivity of crystal （Cry） proteins in the food sources were confirmed by enzyme-linked immunosorbent assay and sensitive-insect bioassays. These results show that L. striatellus is not sensitive to Cry2Aa. We conclude that the dietary exposure system is valid and useful for assessing the toxicity of insecticidal compounds produced by GE plants on planthoppers.

关键词： Cry2Aa E-64 genetically engineered rice potassium arsenate risk assessment

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