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Ultra-light, high flexible and efficient CNTs/Ti3C2-sodium alginate foam for electromagnetic absorption application

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Journal of Materials Science & Technology 2019年第12期35卷 2859-2867页

作者： Xingmin Liu Nan Chai Zhaoju Yu Hailong Xu Xinliang Li Jiquan Liu Xiaowei Yin Ralf Riedel College of Materials Key Laboratory of High Performance Ceramic Fibers(Xiamen University)Ministry of EducationXiamen361005China institutfiir materialwissenschaft Technische Universitdt DarmstadtD-64287DarmstadtGermany College of Materials Fujian Key Laboratory of Advanced MaterialsXiamen UniversityXiamen361005China Science and Technology on Thermostructural Composite Materials Laboratory Northwestern Polytechnical UniversityXi'an710072China Technische Universitat Darmstadt Eduard-Zintl-lnstitutfur Anorganische und Physikalische ChemieAlarich-Weiss-Straβe 4.D-64287DarmstadtGermany

Ultra-light carboxylic functionalized multi-walled carbon nanotubes(CNTs-COOH) and Ti3C2 MXene hybrids modified sodium alginate(CNTs/Ti3C2-SA) based composite foams were prepared through ice-templated freeze-drying method. The microstructure of the synthesized CNTs/Ti3C2 hybrids and CNTs/Ti3C2-SA foams is characterized by the presence of CNTs inserted between MXene layers which prevents their restacking. The resultant CNTs/Ti3C2 hybrids exhibit a unique sandwich-like hierarchical structure. Scanning electron microscopy(SEM) images show that the CNTs/Ti3C2-SA foam exhibits a heterogeneous anisotropic microstructure and CNTs/Ti3C2 hybrids are homogeneously dispersed in the skeleton of the porous foam. In case that the content of the hybrids amounts 40 mg/cm^3, the CNTs/Ti3C2-SA foam possesses excellent electromagnetic(EM) absorption performance with a minimum reflection coefficient(RCmin) as low as-40.0 dB. In case of a sample thickness of 3.95 mm, the RCminreaches-24.4 dB and the effective absorption bandwidth covers the whole X band from 8.2 to 12.4 GHz. A control test shows that, with the same absorbent content, the CNTs/Ti3C2-SA foam exhibits a far better EM performance than that of CNT-free Ti3C2-SA foam.

关键词： Carbon nanotubes MXene Sodium alginate Electromagnetic absorption properties

Design and Synthesis of Potential Macrocyclic Zinc Metalloprotease Inhibitors

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Chinese Journal of Chemistry 2006年第8期24卷 1080-1085页

作者：赵宝祥 SCHAUDT,Marco BLECHERT,Siegfried Institute of Organic Chemistry School of Chemistry and Chemical Engineering Shandong University Jinan Shandong 250100 China institutfiir Chemie Technische Universitat Berlin Strasse des 17. Juni 135 D-10623 Berlin Germany

A series of succinate-derived macrocyclic amides 1 were synthezized using ring-closing metathesis in the key step. The substrate scope includes rings of 11 to 14 members. The cyclic dicarboxylic acids 1 represent a family of new model compounds for potential zinc metalloprotease inhibitors. The metathesis precursors were provided by amide coupling of tert-butyl 3-carboxyhex-5-enoate 2 with numerous side chain alkenylated amino acid esters of general type 3 derived from L-tyrosine and L-cysteine.

关键词： metathesis macrocycle aminoacid derivative

TEXTURE AND CRYSTALLINITY EVOLUTION IN ISOTACTIC POLYPROPYLENE INDUCED BY ROLLING AND THEIR INFLUENCE ON MECHANICAL PROPERTIES

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Chinese Journal of Polymer Science 2006年第4期24卷 403-411页

作者： Dierk Raabe 贾涓 Max-Planck-Institut für Eisenforschung Max-Planck-Str.1 Düsseldorf 40237Germany Department of Materials University of Science and Technology Beijing Beijing 100083 China Max-Planck-Institutfiir Eisenforschung Max-Planck-Str. 1 Dusseldorf 40237 Germany

The orientation and crystallinity evolution of isotactic polypropylene （iPP） induced by rolling were studied using wide angle X-ray scattering with an area detector. The tensile mechanical properties of rolled isotactic polypropylene sheets were also measured in this work. The texture component method was used to analyze the rolling texture. The rolling texture consists mainly of （010）[001], （130）[001] and [001]//RD fiber components in the sample with a rolling true strain of 1.5. The results reveal that crystallinity drastically decreases during rolling. It is suggested that amorphization is a deformation mechanism which takes place as an alternative to crystallographic intralamellar slip depending on the orientation of the lamellae. Both the orientation and crystallinity affect the tensile mechanical properties of rolled polypropylene. Crystallinity influences the elastic modulus on both directions and yield strength on transverse direction at the first stage of deformation. Orientation is the main reason for the changes of mechanical properties, especially at the latter part of deformation. The changes of both tensile strength and elongation percentage on rolling direction are larger than those on transverse direction, which results from the orientation. At last, the anisotropic mechanical properties occur on the rolling and transverse direction： high tensile strength with low elongation percentage on rolling direction and low tensile strength with high elongation percentage on transverse direction.

关键词： Isotactic polypropylene (iPP) Texture Crystallinity Orientation Mechanical properties.

Development of a Full Parameterized FE-modeling Tool for Efficient Vibration Investigations on End Windings of Turbo- and Hydro-Generators

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Journal of Energy and Power Engineering 2013年第8期7卷 1496-1504页

作者： Bemd Schlegl Christian Scheinecker Andreas Marn Fritz Neumayer Mario Himmelreich Franz Heitmeir Machine Dynamics and Acoustics Department Andritz Hydro GmbH Weiz 8160 Osterreich institutfiir Thermische Turbomaschinen und Maschinendynamilq Technische Universitat Graz Graz 8010 Osterreich

End windings of generators are excited to vibrations due to electromagnetic forces which can cause severe damage and noise. To avoid this, it is important to predict the natural frequencies and modes of the end windings with finite elements. Due to the complex structure and unknown boundary conditions, the conventionally calculation of stator end windings has been very difficult and time consuming up to now. This paper describes the development of a full parameterized modeling tool, which allows a quick calculation of natural frequencies during the design phase of the generator. To keep the computing time low, it is important to find a way to get exact calculation results without detailed modeling of all pans. Additionally, special attention was paid to the active part, which has been replaced by spring-damper elements, and the determination of their stiffness via experimental modal analysis combined with finite element calculations.

关键词： Electrical machines end windings finite element method generators hydro generator power generation vibrationproblems.

Pulsed laser reshaping and fragmentation of upconversion nanoparticles-from hexagonal prisms to ID nanorods through“Medusa”-like structures

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Nano Research 2021年第4期14卷 1141-1148页

作者： Laszlo Sajti Denis N.Karimov Vasilina V.Rocheva Nataliya A.Arkharova Kirill V.Khaydukov Oleg I.Lebedev Alexey E.Voloshin Alla N.Generalova Boris N.Chichkov Evgeny V.Khaydukov AIT Austrian Institute of Technology GmbH Wiener Neustadt2700Austria Federal Scientific Research Centre“Crystallography and Photonics”Russian Academy of Sciences Moscow119333Russia Laboratoire CRISMAT UMR6508CNRS-ENSIACENUniversite CaenCaen14050France Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences Moscow 117997Russia institutfiir Quantenoptik Leibniz Universitat HannoverHannover30167Germany Center of Biomedical Engineering Institute of Molecular Medicine Sechenov First Moscow State Medical UniversityMoscow119991Russia

One dimensional(1D)nanostructures attract considerable attention,enabling a broad application owing to their unique ***,the precise mechanism of 1D morphology attainment remains a matter of *** this study,ultrafast picosecond(ps)laser-induced treatment on upconversion nanoparticles(UCNPs)is offered as a tool for 1 D-nanostructures ***,reshaping through recrystallization process and bioadaptation of initially hydrophobic(β-Na_(1.5)Y_(1.5_)F_(6):Yb^(3+),Tm^(3+)/β-Na_(1.5)Y_(1.5_)F_(6))core/shell nanoparticles by means of one-step laser treatment in water are demonstrated.“True”1D nanostructures through"Medusa^-like structures can be obtained,maintaining anti-Stokes luminescence functionalities.A matter of the one-dimensional UCNPs based on direction of energy migration processes is *** proposed laser treatment approach is suitable for fast UCNP surface modification and nano-to-nano transformation,that open unique opportunities to expand UCNP applications in industry and biomedicine.

关键词： upconversion nanoparticles fluoride crystals upconversion nanorods one-dimensional(1D)structures laser-induced reshaping

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

Unexpected intercalation-dominated potassium storage in WS2 as a I potassium-ion battery anode

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Nano Research 2019年第12期12卷 2997-3002页

作者： Vuhan Wu Yang Xu Yueliang Li Pengbo Lyu Jin Wen Chenglin Zhang Min Zhou Yaoguo Fang Huaping Zhao Ute Kaiser Yong Lei Fachgebiet Angewandte Nanophysik Institutfiir Physik&ZMN MacroNano(ZIK)Technische Universitat IlmenauIlmenau 98693Germany Department of Chemistry University College LondonLondon WC1H OAJUK Central Facility for Electron Microscopy Electron Microscopy Group of Materials ScienceUlm UniversityUlm 89081Germany Department of Physical and Macromolecular Chemistry Faculty of ScienceCharles University12843 Prague 2Czech Republic Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic16610 Prague 6Czech Republic

Unexpected intercalation-dominated process is observed duri ng K^+insertion in WS2 in a voltage range of 0.01-3.0 *** is different fromthe previously reported two-dimensional(2D)transition metal dichalcogenides that undergo a conversion reaction in a low voltage rangewhen used as anodes in potassium-ion ***/discharge processes in the K and Na cells are studied in parallel to demonstrate thedifferention storage *** Na^+storage proceeds through intercalation and conversion reactions while the K^+storage is governedby an intercalation *** to the reversible K^+intercalation in the van der Waals gaps,the WS2 anode exhibits a low decay rate of 0.07%per cycle,delivering a capacity of 103 mAh·g^-1 after 100 cycles at 100 mA·g^-*** maintains 57%capacity at 800 mA·g^-1 and shows stablecyclability up to 400 cycles at 500 mA·g^-*** study proves the facilitation of K^+transport is derived from the intercalation-dominatedmecha ***,the mechanismis verified by the density functional theory(DFT)calculations,showing that the progressive expansion of the interlayer space can account for the observed results.

关键词： potassium-ion battery anode WS2 intercalation