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Tribological behaviour of sintered iron based self-lubricating composites

Friction 2017年第3期5卷 285-307页

作者： Jose Daniel Biasoli DE MELLO Cristiano BINDER Gisele HAMMES Roberto BINDER Aloisio Nelmo klein Laboratorio de Materiais(LabMat) Universidade Federal de Santa Catarina Florianópolis 88.040-900 SC BrazilLaboratorio de Tribologia e Materiais Universidade Federal de Uberl(a)ndia Uberl(a)ndia 38.400-902 MG Brazil Laboratorio de Materiais(LabMat) Universidade Federal de Santa Catarina Florianópolis 88.040-900 SC Brazil Whirlpool Embraco Unit Joinville 89.219-900 SC Brazil

This work is a review of previous works, presenting and discussing the most important results obtained by an ongoing research program towards the development of innovative, low-cost, self-lubricating composites with a low friction coefficient and high mechanical strength and wear resistance. Special emphasis is given to uniaxial die pressing of solid lubricant particles mixed with matrix powders and to metal injection moulding associated with in situ generation of solid lubricant particles. Initially, a microstructural model/processing route (powder injection moulding followed by plasma-assisted debinding and sintering) produced a homogeneous dispersion of in situ generated solid lubricant particles. Micrometric nodules of graphite with diameter smaller than 20 μm were formed, constituting a nanostructured stacking of graphite foils with nanometric thickness. Micro Raman analysis indicated that the graphite nodules were composed of turbostratic 2D graphite having highly misaligned graphene planes separated by large interlamellae distance. Large interplanar distance between the graphene foils and misalignment of these foils were confirmed by transmission electron microscopy and were, probably, the origin of the outstandingly low dry friction coefficient (0.04). The effect of sintering temperature, precursor content, metallic matrix composition and surface finish is also reported. Furthermore, the influence of a double-pressing/double-sintering (DPDS) technique on the tribological performance of self-lubricating uniaxially die-pressed hBN + graphite-Fe-Si-C-Mo composite is also investigated. Moreover, the tribological behaviour of die-pressed Fe-Si-C matrix composites containing 5, 7.5 and 10 wt% solid lubricants (hBN and graphite) added during the mixing step is analysed in terms of mechanical properties and wear mechanisms. Finally, the synergy between solid lubricant particles dispersed in a metallic matrix and fluid lubricants in a cooperative mixed lubrication re

关键词： tribological behaviour powder metallurgy iron based self-lubricating composites turbostratic graphite

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Redox-Dependent Regulation of the Stress-Induced Zinc-Finger Protein SAP12 in Arabidopsis thaliana

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Molecular Plant 2009年第2期2卷 357-367页

作者： Elke Stroeher Xin-Jia Wang Nils Roloff Peter klein Arne Husemann Karl-Josef Dietz Biochemistry and Physiology of Plants Bielefeld University 33501 Bielefeld Germany

The stress-associated protein SAP12 belongs to the stress-associated protein （SAP） family with 14 members in Arabidopsis thaliana. SAP12 contains two AN1 zinc fingers and was identified in diagonal 2D redox SDS-PAGE as a protein undergoing major redox-dependent conformational changes. Its transcript was strongly induced under cold and salt stress in a time-dependent manner similar to SAP10, with high levels after 6 h and decreasing levels after 24 and 48 h. The tran- script regulation resembled those of the stress marker peroxiredoxin PrxllD at 24 and 48 h. Recombinant SAP12 protein showed redox-dependent changes in quaternary structure as visualized by altered electrophoretic mobility in non-reducing SDS polyacrylamide gel electrophoresis. The oxidized oligomer was reduced by high dithiothreitol concentrations, and also by E. coli thioredoxin TrxA with low dithiothreitol （DTF） concentrations or NADPH plus NADPH-dependent thioredoxin reductase. From Western blots, the SAP12 protein amount was estimated to be in the range of 0.5 ngμg^-1 leaf protein. SAP12 protein decreased under salt and cold stress. These data suggest a redox state-linked function of SAP12 in plant cells particularly under cold and salt stress.

关键词： abiotic/environmental stress cold acclimation cell signaling gene expression Arabidopsis A20 and AN1 Zinc finger domains redox regulation stress associated protein thioredoxin.

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Specifc inflammatory osteoclast precursors induced during chronic inflammation give rise to highly active osteoclasts associated with inflammatory bone loss

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Bone Research 2022年第3期10卷 548-564页

作者： Yaron Meirow Milena Jovanovic Yuval Zur Juliana Habib Daniele Filippo Colombo Nira Twaik Hadas Ashkenazi-Preiser Kerem Ben-Meir Ivan Mikula Jr. Or Reuven Guy Kariv Leonor Daniel Saja Baraghithy Yehuda klein Jeroen Krijgsveld Noam Levaot Michal Baniyash The Concern Foundation Laboratories at The Lautenberg Center for Immunology and Cancer Research Israel-Canada Medical Research InstituteFaculty of MedicineThe Hebrew UniversityJerusalemIsrael Department of Physiology and Cell Biology Ben-Gurion University of the NegevBeer-ShevaIsrael Division of Proteomics of Stem Cells and Cancer German Cancer Research Center(DKFZ)HeidelbergGermany Institute for Drug Research Faculty of MedicineThe Hebrew UniversityJerusalemIsrael Hebrew University-Hadassah School of Dental Medicine JerusalemIsrael Heidelberg University Medical FacultyHeidelbergGermany

Elevated osteoclast(OC)activity is a major contributor to inflammatory bone loss(IBL)during chronic inflammatory ***,the specific OC precursors(OCPs)responding to inflammatory cues and the underlying mechanisms leading to IBL are poorly *** identified two distinct OCP subsets:Ly6C^(hi)CD11b^(hi) inflammatory OCPs(iOCPs)induced during chronic inflammation,and homeostatic Ly6C^(hi)CD11b^(lo)OCPs(hOCPs)which remained *** and proteomic characterization revealed that while iOCPs were rare and displayed low osteoclastogenic potential under normal conditions,they expanded during chronic inflammation and generated OCs with enhanced *** contrast,hOCPs were abundant and manifested high osteoclastogenic potential under normal conditions but generated OCs with low activity and were unresponsive to the inflammatory *** derived from iOCPs expressed higher levels of resorptive and metabolic proteins than those generated from hOCPs,highlighting that different osteoclast populations are formed by distinct *** further identified the TNF-αand S100A8/A9 proteins as key regulators that control the iOCP response during chronic ***,we demonstrated that the response of iOCPs but not that of hOCPs was abrogated in tnf-α^(-/-)mice,in correlation with attenuated *** findings suggest a central role for iOCPs in IBL *** can serve as potential biomarkers for IBL detection and possibly as new therapeutic targets to combat IBL in a wide range of inflammatory conditions.

关键词： inflammation inflammatory osteoclast

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Tree diversity and nectar composition affect arthropod visitors on extrafloral nectaries in a diversity experiment

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Journal of Plant Ecology 2017年第1期10卷 201-212页

作者： Michael Staab Joel Methorst Jan Peters Nico Blüthgen Alexandra-Maria klein Faculty of Environment and Natural Resources Chair of Nature Conservation and Landscape EcologyUniversity of FreiburgTennenbacher Straße 479106 FreiburgGermany Institute of Ecology Leuphana University of LüneburgScharnhorststraße 121335 LüneburgGermany Ecological Network Group Department of BiologyTechnical University DarmstadtSchnittspahnstraße 1064287 DarmstadtGermany

Aims Plants with extrafloral nectaries(EFNs)are common in tropical and subtropical habitats and,despite many other arthropods also forage for EFN,most studies solely focused on the defense mutualisms between EFN plants and *** study aims at a quantitative assessment of the entire arthropod community that visits EFN trees to compare visitor communities between different tree species to disentangle the mechanisms that may drive EFN visitor community *** also test for tree diversity effects on EFN visitors,as it is unknown if local tree species richness relates to the abundance and species richness of arthropods foraging for *** We sampled EFN-visiting arthropods in the experimental tree species richness gradient of the BEF-China Experiment,the currently largest forest diversity experiment in the world,and tested if tree species richness affects EFN visitors and if visitor community composition differs between EFN tree *** a second step,we analyzed the EFN of Ailanthus altissima and Triadica cochinchinensis,the two EFN tree species with highest visitor abundance,for sugars and amino acids(AA)to test if tree species-specific differences in nectar chemistry translate to differing visitor ***,we conducted a choice experiment using different artificial nectar solutions to test if nectar quality affects foraging decisions of ants,the most frequent EFN visitors in our study *** Findings EFN trees in young successional forests in subtropical South-East China are visited by a diverse assemblage of arthropods including ants,beetles,flies,and *** ants accounted for about 75%of all individuals,non-ant visitors were by far more species *** abundance and species richness declined with increasing tree species richness,suggesting a resource dilution effect,because plots with more tree species had proportionally less EFN tree individuals and thus lower nectar *** altissima and ***

关键词： amino acids BEF-China choice experiment formicidae HPLC chemical analysis

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迎接家庭新成员为家中添一只宠物狗需要做的准备

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空中英语教室（高级版．彭蒙惠英语） 2023年第12期 26-27,46,47页

作者： Jerry klein 不详

圣诞节即将来临,为自己或家人买一只新幼犬的想法被很多人列在愿望清单的首位。但圣诞节真的是买一只全新幼犬的最佳时机吗?将一只狗或幼犬带人家中应被视为对狗一生的承诺。这不应是一时冲动的购买或添置,而是一个计划深思熟虑之后的... 详细信息

圣诞节即将来临,为自己或家人买一只新幼犬的想法被很多人列在愿望清单的首位。但圣诞节真的是买一只全新幼犬的最佳时机吗?将一只狗或幼犬带人家中应被视为对狗一生的承诺。这不应是一时冲动的购买或添置,而是一个计划深思熟虑之后的结果。

关键词：幼犬宠物狗最佳时机圣诞节清单

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On Locating Malicious Code in Piggybacked Android Apps

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Journal of Computer Science & Technology 2017年第6期32卷 1108-1124页

作者： Li Li Daoyuan Li Tegawende F. Bissyande Jacques klein Haipeng Cai David Lo Yves Le Traon Interdisciplinary Centre for Security Reliability and Trust University of Luxembourg Luxembourg 2721 Luxembourg School of Electrical Engineering and Computer Science Washington State University Washington WA 99163 U.S.A. School of Information Systems Singapore Management University Singapore 178902 Singapore

To devise efficient approaches and tools for detecting malicious packages in the Android ecosystem, researchers are increasingly required to have a deep understanding of malware. There is thus a need to provide a framework for dissecting malware and locating malicious program fragments within app code in order to build a comprehensive dataset of malicious samples. Towards addressing this need, we propose in this work a tool-based approach called HookRanker, which provides ranked lists of potentially malicious packages based on the way malware behaviour code is triggered. With experiments on a ground truth of piggybacked apps, we are able to automatically locate the malicious packages from piggybacked Android apps with an accuracy@5 of 83.6% for such packages that are triggered through method invocations and an accuracy@5 of 82.2% for such packages that are triggered independently.

关键词： Android piggybacked app malicious code HookRanker

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Phase imaging of irradiated foils at the OMEGA EP facility using phase-stepping X-ray Talbot–Lau deflectometry

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High Power Laser Science and Engineering 2023年第4期11卷 45-54页

作者： G.Pérez-Callejo V.Bouffetier L.Ceurvorst T.Goudal S.R.klein D.Svyatskiy M.Holec P.Perez-Martin K.Falk A.Casner T.E.Weber G.Kagan M.P.Valdivia Departamento de Física Teórica Atómica yÓptica Universidad de ValladolidValladolidSpain Universitéde Bordeaux-CNRS-CEA Centre Lasers Intenses et Applications(CELIA)UMR 5107TalenceFrance European XFEL GmbH SchenefeldGermany Laboratory for Laser Energetics RochesterNew YorkUSA CEA-DAM DIFArpajonFrance University of Michigan Ann ArborMichiganUSA Los Alamos National Laboratory Los AlamosNew MexicoUSA Lawrence Livermore National Laboratory LivermoreCaliforniaUSA Helmholtz-Zentrum Dresden-Rossendorf DresdenGermany Technische Universität Dresden DresdenGermany Institute of Physics of the ASCR PragueCzech Republic CEA-CESTA CS 60001Le Barp CedexFrance Blackett Laboratory Imperial College LondonLondonUK Department of Astrophysics and Astronomy The Johns Hopkins UniversityBaltimoreMarylandUSA Center for Energy Research University of California San DiegoSan DiegoCaliforniaUSA

Diagnosing the evolution of laser-generated high energy density(HED)systems is fundamental to develop a correct understanding of the behavior of matter under extreme ***–Lau interferometry constitutes a promising tool,since it permits simultaneous single-shot X-ray radiography and phase-contrast imaging of dense *** present the results of an experiment at OMEGA EP that aims to probe the ablation front of a laser-irradiated foil using a Talbot–Lau X-ray interferometer.A polystyrene(CH)foil was irradiated by a laser of 133 J,1 ns and probed with 8 keV laser-produced backlighter radiation from Cu foils driven by a short-pulse laser(153 J,11 ps).The ablation front interferograms were processed in combination with a set of reference images obtained ex situ using *** managed to obtain attenuation and phase-shift images of a laser-irradiated foil for electron densities above 1022 cm−*** results showcase the capabilities of Talbot–Lau X-ray diagnostic methods to diagnose HED laser-generated plasmas through high-resolution imaging.

关键词： deflectometry OMEGA EP phase-contrast imaging Talbot-Lau X-ray interferometry

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Detection and upconversion of three-dimensional MMW/THz images to the visible

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Photonics Research 2016年第6期4卷 306-312页

作者： Avihai Aharon(Akram) Daniel Rozban Avi klein Amir Abramovich Yitzhak Yitzhaky Natan S.Kopeika Department of Electrical and Electronic Engineering Ariel University Department of Electrical and Computer Engineering Ben-Gurion University of the Negev Department of Electro-Optical Engineering Ben-Gurion University of the Negev

We present an inexpensive technique to obtain a three-dimensional(3D) millimeter wave(MMW) and terahertz(THz) image using upconversion. In this work we describe and demonstrate a method for upconversion of MMW/THz radiation to the visual band using a very inexpensive miniature glow discharge detector(GDD) and a silicon photodetector. We present MMW/THz upconversion images based on measuring the visual light emitting from the GDD rather than its electrical current. The results show better response time and better sensitivity compared to the electronic detection performed previously. Furthermore, in this work we perform frequency modulation continuous wave(FMCW) radar detection based on this method using a GDD lamp, with a photodetector to measure GDD light emission. By using FMCW detection, the range in addition to the intensity at each pixel can be obtained,thus yielding the 3D image. The GDD acts as a heterodyne mixer not only electronically but also optically. The suggested 3D upconversion technique using the GDD is simple and inexpensive and has better performance compared to other MMW/THz imaging systems suggested in the literature. This method provides minimum detectable signal power that is about 6 orders of magnitude better than similar plasma systems due to the very large internal signal gain deriving from the much smaller electrode separation and resulting in much higher plasma electric field.

关键词： THz Detection and upconversion of three-dimensional MMW/THz images to the visible FMCW

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Protein Domains Involved in Assembly in the Endoplasmic Reticulum Promote Vacuolar Delivery when Fused to Secretory GFP, Indicating a Protein Quality Control Pathway for Degradation in the Plant Vacuole

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Molecular Plant 2008年第6期1卷 1067-1076页

作者： Ombretta Foresti Francesca De Marchis Maddalena de Virgilio Eva M. klein Sergio Arcioni Michele Bellucci Alessandro Vitale Istituto di Biologia e Biotecnologia Agraria Consiglio Nazionale delle Ricerche via Bassini 15 20133 Milano Italy EU Istituto di Genetica Vegetale Consiglio Nazionale delle Ricerche via della Madonna Alta 130 06128 Perugia Italy EU

The correct folding and assembly of newly synthesized secretory proteins are monitored by the protein quality control system of the endoplasmic reticulum （ER）. Through interactions with chaperones such as the binding protein （BiP） and other folding helpers, quality control favors productive folding and sorts for degradation defective proteins. A major route for quality control degradation identified in yeast, plants, and animals is constituted by retrotranslocation from the ER to the cytosol and subsequent disposal by the ubiquitin/proteasome system, but alternative routes involving the vacuole have been identified in yeast. In this study, we have studied the destiny of sGFP418, a fusion between a secretory form of GFP and a domain of the vacuolar protein phaseolin that is involved in the correct assembly of phaseolin and in BiP recognition of unassembled subunits. We show that sGFP418, despite lacking the phaseolin vacuolar sorting signal, is delivered to the vacuole and fragmented, in a process that is inhibited by the secretory traffic inhibitor brefeldin A. Moreover, a fusion between GFP and a domain of the maize storage protein γ-zein involved in zein polymerization also undergoes post-translational fragmentation similar to that of sGFP418. These results show that defective secretory proteins with permanently exposed sequences normally involved in oligomerization can be delivered to the vacuole by secretory traffic. This strongly suggests the existence of a plant vacuolar sorting mechanism devoted to the disposal of defective secretory proteins.

关键词： Endoplasmic reticulum protein degradation protein traffic vacuole.

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小型计算机对平面断层图象的3—D重建

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放射学实践 1991年第3期6卷 106-109页

作者： R.Krasny M.klein W.Schneider P.Jensch 刘建斌 Klinik fur Radiologische Diagnostik Klinikum der RWTH Aachen Institut fur Allgemeine Elektrotechnik und Datenverarbeitung RWTH Aachen 中国康复研究中心

三维成象是计算机数据处理的一种广泛应用。为此,在技术领域中建立了一些系统,如CAD(Computer Aided Design)和CAM(Computer Aided Manufacturing)。80年代尽管有些厂家已研制出各种具有相当效率的系统,但暂时还没有获得广泛的临床应用。

关键词：计算机平面断层图象 3-D重建放射造影术

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