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聚乙烯醇/微纤化纤维素复合微发泡材料的制备

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化工学报 2015年第2期66卷 806-813页

作者：赵娜李倩 Chul b.park 郑州大学微纳成型技术国家级国际联合研究中心微成型技术河南省重点实验室河南郑州450001 郑州大学橡塑模具国家工程研究中心河南郑州450002 Microcellular Plastics Manufacturing Laboratory University of Toronto

通过溶液浇铸法制备了聚乙烯醇(PVOH)/微纤化纤维素(MFC)复合薄膜材料,以超临界二氧化碳(scCO2)为物理发泡剂,采用间歇式降压法制备了一系列PVOH/MFC复合微发泡材料,主要讨论了在没有水分的影响下,不同发泡温度和时间以及MFC含量对PVOH/... 详细信息

通过溶液浇铸法制备了聚乙烯醇(PVOH)/微纤化纤维素(MFC)复合薄膜材料,以超临界二氧化碳(scCO2)为物理发泡剂,采用间歇式降压法制备了一系列PVOH/MFC复合微发泡材料,主要讨论了在没有水分的影响下,不同发泡温度和时间以及MFC含量对PVOH/MFC复合微发泡材料的泡孔形貌、泡孔尺寸和泡孔密度的影响;同时,也对MFC的分散性和PVOH/MFC复合材料的流变性能和热性能对发泡行为的影响进行了研究。实验结果表明,均匀分散在PVOH基体中的MFC作为异相成核剂提高了气孔成核能力,且随着MFC含量的增加,泡孔尺寸降低,泡孔密度增大;并研究了发泡温度对PVOH/MFC复合材料的发泡形貌的影响,获得最优发泡温度。

关键词：聚乙烯醇超临界二氧化碳挤出发泡成核

Isomorphisms between Quasi-banach Algebras

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Chinese Annals of Mathematics,Series b 2007年第3期28卷 353-362页

作者： Choonkil park Department of Mathematics Hanyang UniversitySeoul 133-791Korea.

In this paper, the author proves the Hyers-Ulam-Rassias stability of homomorphisms in quasi-banach algebras. This is used to investigate isomorphisms between quasi-banach algebras.

关键词： Cauchy functional equation Jensen functional equation Quasi-banachalgebra Hyers-Ulam-Rassias stability Homomorphism p-banach algebra

Wedge Operations and Doubling Operations of Real Toric Manifolds

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Chinese Annals of Mathematics,Series b 2017年第6期38卷 1321-1334页

作者： Hanchul park School of Mathematics Korea Institute for Advanced Study85 Hoegiro Dongdmemun-guSeoul 130-722Republic of Korea

This paper deals with two things. First, the cohomology of canonical extensions of real topological toric manifolds is computed when coefficient ring G is a commutative ring in which 2 is unit in G. Second, the author focuses on a specific canonical extensions called doublings and presents their various properties. They include existence of infinitely many real topological toric manifolds admitting complex structures, and a way to construct infinitely many real toric manifolds which have an odd torsion in their cohomology ***, some questions about real topological toric manifolds related to Halperin's toral rank conjecture are presented.

关键词： Real toric manifold Small cover Real topological toric manifold Coho-mology ring Doubling Simplicial wedge Rational homology sphere

Intercept-resend attack on six-state quantum key distribution over collective-rotation noise channels

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Chinese Physics b 2016年第7期25卷 131-137页

作者： kevin Garapo Mhlambululi Mafu Francesco Petruccione Centre for Quantum Technology School of Chemistry and PhysicsUniversity of KwaZulu-Natal P/Bag X54001 Durban 4000 South Africa Department of Physics and Astronomy Botswana International University of Science and Technology P/Bag 16 Palapye Botswana National Institute for Theoretical Physics (NITheP) KwaZulu-Natal South Africa

We investigate the effect of collective-rotation noise on the security of the six-state quantum key distribution. We study the case where the eavesdropper, Eve, performs an intercept-resend attack on the quantum communication between Alice, the sender, and bob, the receiver. We first derive the collective-rotation noise model for the six-state protocol and then parameterize the mutual information between Alice and Eve. We then derive quantum bit error rate for three interceptresend attack scenarios. We observe that the six-state protocol is robust against intercept-resend attacks on collective rotation noise channels when the rotation angle is kept within certain bounds.

关键词： six states quantum key distribution security collective-rotation noise

A Unified Fixed Point Theory in Generalized Convex Spaces

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Acta Mathematica Sinica,English Series 2007年第8期23卷 1509-1526页

作者： Sehie park The National Academy of Sciences Republic of Korea School of Mathematical SciencesSeoul National UniversitySeoul 151-747Korea

Let b be the class of ＇better＇ admissible multimaps due to the author. We introduce new concepts of admissibility （in the sense of Klee） and of Klee approximability for subsets of G-convex uniform spaces and show that any compact closed multimap in b from a G-convex space into itself with the Klee approximable range has a fixed point. This new theorem contains a large number of known results on topological vector spaces or on various subclasses of the class of admissible G-convex spaces. Such subclasses are those of O-spaces, sets of the Zima-Hadzic type, locally G-convex spaces, and LG-spaces. Mutual relations among those subclasses and some related results are added.

关键词： multimap classes b and U^kc Ф-map Ф-set Ф-space admissible G-convex space the Zimatype locally G-convex space LG-space

Taxonomy and phylogeny of operculate discomycetes: Pezizomycetes

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Fungal Diversity 2018年第3期90卷 161-243页

作者： Anusha H.Ekanayaka kevin D.Hyde E.b.Gareth Jones Qi Zhao Key Laboratory for Plant Diversity and biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650201YunnanChina Center of Excellence in Fungal Research Mae Fah Luang UniversityChiang Rai 57100Thailand Department of Entomology and Plant Pathology Faculty of AgricultureChiang Mai UniversityChiang Mai 50200Thailand

The class Pezizomycetes is monophyletic within the subdivision Pezizomycotina. The main distinguishing character of thisclass is operculate asci, although in some taxa this character has been lost. The circumscription of the families and genericlevel delimitation in Pezizomycetes is still controversial, although several molecular phylogenetic studies have beenpublished on this group. This paper reviews 21 families of Pezizomycetes including five new families, which are introduced here, viz. Kallistoskyphaceae, Pseudombrophilaceae, Pulvinulaceae, Strobiloscyphaceae and Tarzettaceae. Moreover, this study provides a modified backbone tree based on phylogenetic analysis of five combined loci. Descriptions andillustrations of representative taxa for the families are provided from collections made in China, Thailand and the UK,herbarium material from international herbaria (FH, FLAS, H, HKAS and MA) and the literature. Pezizales separates intosix major clades. Clade 1 of Pezizales includes the families Ascobolaceae and Pezizaceae. Clade 2 is the new familyKallistoskyphaceae. Clade 3 comprises the families Caloscyphaceae, Karstenellaceae and Rhizinaceae. Clade 4 representsthe families Discinaceae, Helvellaceae, Morchellaceae, Tuberaceae and Underwoodia columnaris lineage. Clade 5includes Chorioactidaceae, Sarcoscyphaceae and Sarcosomataceae and Clade 6 comprises Ascodesmidaceae, Glaziellaceae, Otideaceae, Pseudombrophilaceae, Pulvinulaceae, Pyronemataceae, Strobiloscyphaceae and Tarzettaceae. Newsequence data belonging to ITS, LSU, SSU, TEF, RPb2 gene regions from 40 pezizalian species are provided here. Thepaper provides a working document for apothecial Pezizomycetes which can be modified as new data comes to light. It ishoped that by illustrating taxa we provide stimulation and interest in the operculate discomycetes, so that further research iscarried out on this remarkable, but poorly studied group of fungi.

关键词： Apothecial ascomycetes Five new families Multi-gene analysis Systematics Tuberales

Microcellular foamed polyamide 6/carbon nanotube composites withsuperior electromagnetic wave absorption

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Journal of Materials Science & Technology 2022年第22期117卷 215-224页

作者： Menglong Xu Linfeng Wei Li Ma Jiawei Lu Tao Liu Ling Zhang Ling Zhao Chul b.park State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China Department of Mechanical and Industrial Engineering University of Toronto5 King’s College RoadTorontoOntario M5S 3G8Canada Shanghai Engineering Research Center of Hierarchical Nanomaterials School of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China

Electromagnetic (EM) wave pollution causing damage to precision equipment and threatening thehealth of living organisms has attracted considerable attention. Herein, promising microcellular foamedpolyamide 6 (PA6)/carbon nanotube (CNT) composites for highly efficient EM wave absorption were successfully fabricated using supercritical CO_(2) foaming. Nanocomposites foams with a void fraction rangingfrom 38.7% to 85.1% were achieved, providing a platform to assess the correlation of the electrical conductivity, the dielectric permittivity and the EM wave absorption properties with porosity. Notably, theFoam-257.5C sample with a void fraction of 38.7% exhibited outstanding EM wave absorption characteristics at a thickness of only 1.59 mm and an ultra-low reflection loss value of -55.3 db (99.9997% wave absorption). Most importantly, the effective absorption bandwidth (EAb) of the Foam-257.5C sample couldcover the entire Ku band (12.4–18 GHz) by slightly adjusting the thickness from 1.20 to 1.60 mm. Thesuperior EM wave absorption performance of the Foam-257.5C sample was attributed to multiple reflections and scattering at the solid-gas interfaces, favorable impedance matching due to the existence ofa large polymer-air interface area, conductive loss near the interfaces and interfacial polarization. Thus,this study offers an eco-friendly, simple and versatile methodology to develop high-efficiency, flexiblepolymer-based EM wave absorbents.

关键词： Polymer nanocomposites Supercritical CO_(2)foaming Void fraction Dielectric properties Electromagnetic wave absorption

Multidimensional Hybrid Architecture Encapsulating Cobalt Oxide Nanoparticles into Carbon Nanotube branched Nitrogen-Doped Reduced Graphene Oxide Networks for Lithium–Sulfur batteries

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Energy & Environmental Materials 2022年第2期5卷 555-564页

作者： Jeong Seok Yeon Young Hun Ko Tae Ho park Hyunyoung park Jongsoon Kim Ho Seok park School of Chemical Engineering College of EngineeringSungkyunkwan University2066Seobu-roJangan-guSuwon-si Gyeonggi-do 440-746Korea Advanced batteries Research Center Korea Electronics Technology Institute25Saenari-roBundang-guSeongnam-si Gyeonggi-do 13509Korea Department of Energy Science Sungkyunkwan University2066Seobu-roJangan-guSuwon-si Gyeonggi-do 440-746Korea Department of Health Sciences and Technology Samsung Advanced Institute for Health Sciences and Technology(SAIHST)Sungkyunkwan University2066SeoburoJangan-guSuwon 440-746South Korea

Lithium–sulfur batteries(LSbs)are regarded as promising candidates for the next-generation energy storage devices owing to their high-theoretical capacity(1675 mAh g^(−1))and affordable ***,several limitations of LSbs such as the lithium polysulfide shuttle,large volume expansion,and low electrical conductivity of sulfur need to be resolved for practical *** address these limitations,herein,a multidimensional architectured hybrid(Co@CNT/nG),where Co_(3)O_(4) nanoparticles are encapsulated into threedimensional(3D)porous N-doped reduced graphene oxide interconnected with carbon nanotube(CNT)branches,is synthesized through a simple pyrolysis *** synergistic effect achieved through the homogeneously distributed and encapsulated Co_(3)O_(4) nanoparticles,the interconnected CNT branches,and the 3D hierarchical porous structure and N-doping of Co@CNT/nG significantly suppresses the shuttle effect of lithium polysulfides and enhances the conversion redox kinetics for the improved sulfur *** validate this effect through various measurements including symmetric cells,Li_(2)S nucleation,shuttle currents,Tafel slopes,diffusion coefficients,and post-mortem ***,Co@CNT/nG-70S-based LSb cells achieve a high-specific capacity of 1193.1 mAh g^(−1) at 0.1 C and a low capacity decay rate of 0.030%per cycle for 700 cycles at 5 C,delivering a high areal capacity of 5.62 mAh cm^(−2) even with a loading of 6.5 mg cm^(−2).

关键词： graphene/CNT hybrid lithium-sulfur batteries multidimensional architecture nanoparticle encapsulation redox promoter

Temperature and composition dependent screw dislocation mobility in austenitic stainless steels from large-scale molecular dynamics

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npj Computational Materials 2020年第1期6卷 176-185页

作者： kevin Chu Michael E.Foster Ryan b.Sills Xiaowang Zhou Ting Zhu David L.McDowell School of Materials Science and Engineering Georgia Institute of Technology AtlantaAtlantaGA 30332USA Sandia National Laboratories LivermoreCA 94550USA Department of Materials Science and Engineering Rutgers UniversityPiscatawayNJ 08854USA Woodruff School of Mechanical Engineering Georgia Institute of TechnologyAtlantaGA 30332USA

Extensive molecular dynamics simulations are performed to determine screw dislocation mobility in austenitic Fe_(0.7)NixCr_(0.3-x) stainless steels as a function of temperature ranging from 100 to 1300 K,resolved shear stress from 30 to 140 MPa,and Ni composition from 0.0 to 30.0 at%.These mobility data are fitted to a linear mobility law with a nonzero stress offset,referred to as the threshold *** find that both the linear drag coefficient and the threshold stress increase with Ni *** drag coefficient increases with temperature,whereas the threshold stress decreases with *** on these calculations,we determine fitting functions for the linear solute drag coefficient as a function of temperature and *** mobility laws determined in this study may serve to inform dislocation dynamics simulations pertinent to dislocation network evolution at elevated temperatures for a wide composition range of austenitic stainless steels.

关键词： austenitic dislocation dynamics