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Effect of Ce-base mischmetal addition on the microstructure and mechanical properties of hot-rolled ZK60 alloy

journal of Magnesium and Alloys 2021年第3期9卷 995-1006页

作者： E.p.Silva R.H.Buzolin f.Marques f.Soldera U.Alfaro H.C.pinto Institute of Engineering Science and Technology(IECT)Federal University of Vales do Jequitinhonha e Mucuri(UFVJM)JanaúbaMGBrazil São Carlos School of Engineering(EESC) University of São Paulo(USP)Department of Materials EngineeringCEP 13563-120 São Carlos-SPBrazil Christian Doppler Laboratory for Design of high-performance alloys by thermomechanical processing Kopernikusgasse 24/I8010 GrazAustria Technische Universität Graz(TU Graz) Institute of Materials ScienceJoining and FormingKopernikusgasse 24/I8010 GrazAustria Institute of functional Materials Department of Materials Science and EngineeringSaarland UniversitySaarbrueckenGermany German Aerospace Center(DLR)Institute of Materials Research Linder Höhe51147 CologneGermany

Mg-Zn-Zr(ZK)alloys exhibit notably high mechanical strength amongst all magnesium alloy ***,due to the formation of low melting point Mg_3Zn_7-precipitates,these alloys are susceptible to hot cracking,thus compromising their metallurgical *** addition of rare earths to ZK alloys is an alternative to form higher melting point intermetallic compounds,speed up dynamic recrystallization,refine grain size,enhance corrosion resistance and extend the service temperature due to improved creep *** work deals with the effect of Ce-base mischmetal addition on the hot rolling behaviour of as-cast ZK60 *** microstructure investigation conducted using electron microscopy and X-Ray diffraction shows that precipitation of Mg_(7)Zn_(3) intermetallics occur during hot rolling,whereas no further precipitation is observed for the ZK60-Mm *** fragmentation of the intermetallic compounds occur during hot rolling and finer particles of Mg_(7)Zn_(3) are observed for the ZK60,whereas Mg_(7)Zn_(3) and Mg Zn_(2) Ce intermetallics are formed in the alloy modified with mischmetal addition.A higher fraction of dynamically recrystallized grains is observed for the ZK60-Mm in comparison to the *** recrystallization takes place in ZK60 with the formation of sub-grains near to the intermetallics and the addition of mischmetal promotes the occurrence of discontinuous recrystallization with the nucleation of new grains close to the *** mechanical strength and,in particular,the ductility of the hot-rolled alloys are notably improved when compared to the same alloys in the as-cast *** mechanical strength is,however,higher for the ZK60 *** solid solution strengthening,softer Mg Zn_(2) Ce intermetallics and more extensive recrystallization contribute to reduce the mechanical strength of *** in both alloys are initiated at coarse intermetallics and propagate through intermetallic-rich regions.

关键词： Magnesium alloys Hot rolling Mischmetal Recrystallization Microstructure Mechanical properties

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Scalable integration of nano-,and microfluidics with hybrid two-photon lithography

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Microsystems & Nanoengineering 2019年第1期5卷 264-272页

作者： Oliver Vanderpoorten Quentin peter pavan K.Challa Ulrich f.Keyser jeremy Baumberg Clemens f.Kaminski Tuomas p.j.Knowles Department of Chemical Engineering and Biotechnology University of CambridgePhilippa Fawcett DriveCambridge CB30ASUK Department of Chemistry University of CambridgeLensfield RoadCambridge CB21EWUK Cavendish Laboratory Department of PhysicsUniversity of CambridgeJ.J.Thomson AvenueCambridge CB30HEUK

Nanofluidic devices have great potential for applications in areas ranging from renewable energy to human health.A crucial requirement for the successful operation of nanofluidic devices is the ability to interface them in a scalable manner with the outside ***,we demonstrate a hybrid two photon nanolithography approach interfaced with conventional mask whole-wafer UV-photolithography to generate master wafers for the fabrication of integrated micro and nanofluidic *** this approach we demonstrate the fabrication of molds from SU-8 photoresist with nanofluidic features down to 230 nm lateral width and channel heights from micron to sub-100 *** electron microscopy and atomic force microscopy were used to characterize the printing capabilities of the system and show the integration of nanofluidic channels into an existing microfluidic chip *** functionality of the devices was demonstrated through super-resolution microscopy,allowing the observation of features below the diffraction limit of light produced using our *** molecule localization of diffusing dye molecules verified the successful imprint of nanochannels and the spatial confinement of molecules to 200 nm across the nanochannel molded from the master *** approach integrates readily with current microfluidic fabrication methods and allows the combination of microfluidic devices with locally two-photon-written nano-sized functionalities,enabling rapid nanofluidic device fabrication and enhancement of existing microfluidic device architectures with nanofluidic features.

关键词： lithography integration fluid

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Green and red Anti-Stokes emission of U^(3+): LaCl_3 produced by infrared laser

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原子与分子物理学报 2001年第1期18卷 4-6页

作者： Yin Min Deren p j joubert M f Krupa j C 中国科学技术大学结构分析开放实验室安徽合肥 230026 Institute of Low Temperature and Structure Researches 波兰 50950 Universite Claude Bernard Lyon 法国 Groupe de Radiochimie Institut de Physique Nucleaire 法国 91406

Anti-Stokes green and red emission from U3+: LaCl3 can be produced by infrared laser excitation at 975.3 nm, 977.7 nm and 979.4 nm at 8K. The upconversion luminescence intensity dependence upon the excitation laser power was measured and analyzed. The results show that depending on the excitation wavelength, the mechanisms responsible for the upconversion process are two-photon absorption and excited-state absorption.

关键词：非燃烧发光三氯化镧晶体红外激光

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New patterns of the tree beta diversity and its determinants in the largest savanna and wetland biomes of South America

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plant Diversity 2023年第4期45卷 369-384页

作者： Karla j.p.Silva-Souza Maíra G.pivato Vinícius C.Silva Ricardo f.Haidar Alexandre f.Souza Departamento de Ecologia Universidade Federal do Rio Grande do NorteRNBrazil Curso de Engenharia Ambiental Universidade Federal do TocantinsTOBrazil

Clear and data-driven bioregionalizations can provide a framework to test hypotheses and base biodiversity *** we used occurrence and abundance data in combination with objective analytical methods to propose two bioregionalization schemes for tree species of the Cerrado and the pantanal in South *** also evaluated the contribution of three sets of determinants of the occurrence-and abundance-based *** compiled data on tree species composition from 894 local assemblages based on species occurrences,and from 658 local assemblages based on species *** used an unconstrained community-level modelling approach and clustering techniques to identify and map tree subregions for the occurrence and the abundance data sets,*** clustering analyses were conducted to investigate floristic affinities between the subregions and to map broader floristic *** used multinomial logistic regression models,deviance partitioning,and rank-sum tests to assess the main subregion *** identified 18 occurrence-and four abundance-based subregions in the *** hierarchical classifications grouped the occurrence-based subregions into nine floristic zones and abundance-based subregions into two broad floristic *** in subregions were explained mainly by environmental factors and spatial structure in both occurrence and abundance data *** occurrence-and abundance-based subregions are complementary approaches to disentangle macroecological patterns and to plan conservation efforts in the Cerrado and the *** findings based on occurrence data revealed more complex and interdigitated boundaries between subregions of tree species than previously *** environment,historical stability,and human effects act in a synergetic way on the distribution of the ***,the relevance of contemporary environmental factors to the subregion patterns we found alert us to the profound im

关键词： Cerrado pantanal Savanna Biogeographical regionalization Biodiversity hotspot South America

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Characterization of phases in an As-cast Copper-Manganese-Aluminum Alloy

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journal of Materials Science & Technology 2006年第6期22卷 779-784页

作者： j.Iqbal f.Hasan f.Ahmad Department of Metallurgical and Materials Engineering University of Engineering and TechnologyLahorePakistan

Copper-manganese-aluminum （CMA） alloys, containing small additions of fe, Ni, and Si, exhibit good strength and remarkable corrosion resistance against sea water. The alloys are used in as-cast condition, and their microstructure can show wide variations. The morphology, crystallography and composition of the phases presented in an as-cast （CMA） alloy of nominal composition Cu-14%Mn-8%Al-3%fe-2%Ni were investigated using optical, electron optical, and microprobe analytical techniques. The as-cast microstructure consisted of the grains of fcc α and bcc β-phases alongwith intermetallic precipitates of various morphologies. The room temperature microstructure exhibited four different types of precipitates inside the α-grains： the ＇large＇ dendritic-shaped particles and the cuboid-shaped precipitates, which were rich in fe and Mn and had an fcc structure, while the ＇small＇ dendritic-shaped particles and the globular precipitates were based on feaAI and had DO3 structure. These four different morphologies of intermetallic precipitates exhibited discrete orientation-relationships with the α-matrix. The β-grains only contained very small cuboid shaped precipitates, which could only be resolved through transmission electron microscopy. These precipitates were found to be based on fe3Al and had the DO3 structure.

关键词： Orientation relationship DO3 structure Intermetallic phases

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Substrate Strengthening of CVD Coated Steels

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材料热处理学报 2004年第05B期25卷 791-795页

作者： O. Kessler M. Heidkamp f. Hoffmann p. Mayr Stiftung Institutfiir Werkstofftechnik Bremen GermanyStiftung Institutfiir Werkstofftechnik Bremen GermanyStiftung Institutfiir Werkstofftechnik Bremen GermanyStiftung Institutfiir Werkstofftechnik Bremen Germany

properties of components and tools can be improved by the combination of coating and heat treatment processes due to the addition of single process advantages and due to the utilization of process interactions. Several low and high alloyed, structural and tool steels (AISI 4140, 52100, H13, A2, D2, etc.) have been treated by CVD-TiN-coating plus laser beam hardening respectively carburizing plus CVD-TiN-coating. Homogeneous, dense TiN-coatings with high hardness, high compressive residual stresses and good adhesion were supported by high strength substrate surfaces. Especially CVD plus laser beam hardening offers the possibility to reduce distortion due to the small heated surface volume.

关键词： CVD 衬底加强镀层钢板激光束强化渗碳

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Relationship of Corrosion Behavior Between Single-phase Equiatomic CoCrNi,CoCrNife,CoCrNifeMn Alloys and Their Constituents in NaCl Solution

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Acta Metallurgica Sinica(English Letters) 2021年第11期34卷 1574-1584页

作者： D.p.Wang j.W.Shen Z.Chen f.G.Chen p.Y.Guo Y.X.Geng Y.X.Wang School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China

The composition is a significant issue for corrosion resistance of metallic *** reveal the correlation of corrosion behavior between multiprinciple alloys and their constituents,a series of single-phase equiatomic alloys of CoCrNi,CoCrNife and CoCrNifeMn was *** electrochemical and scanning electron microscope results demonstrated that corrosion resistance of the equiatomic alloys in 0.1 M NaCl solution is located in the range but not the average value of their constituents.X-ray photoelectron spectroscopy analysis indicated that the protective performance of passive film is mainly determined by the constituent with the highest corrosion resistance and the breakdown of passive film is mainly dominated by the elements with the highest corrosion *** findings can guide the materials design of multiprinciple alloys with expected corrosion performance.

关键词： High-entropy alloy Corrosion Constituent X-ray photoelectron spectroscopy(XpS) passive films

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Application of geovisual analytics to modelling the movements of ruminants in the rural landscape using satellite tracking data

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International journal of Digital Earth 2015年第7期8卷 579-593页

作者： K.K.Benke f.Sheth K.Betteridge C.j.pettit j.-p.Aurambouta Department of Environment and primary Industries–parkville Centre ParkvilleVICAustralia AgResearch Grasslands Palmerston NorthNew Zealand AURIN Faculty of ArchitectureBuilding and PlanningUniversity of MelbourneParkvilleVICAustralia

Geovisual analytics provides a framework for the development of decision support tools for landscape design,analysis and *** important application is modelling the spatial-temporal movements of ruminants and their grazing behaviour using global positioning system(GpS)collar *** study describes the mapping and analysis of spatial distributions of animal waste products(which correlate with farm nitrogen[N]emissions)and also determination of animal feeding preferences(which correlate with animal welfare and production).Segmentation of local regions of animal N emissions provides support in meeting targets for local and international N leaching and greenhouse gas *** agent-based model was used for prescreening in order to gain insights into the clustering behaviour of sheep during feeding *** spatial analysis demonstrated that livestock excreta are not always randomly located,but concentrated around highly localised animal gathering points,separated by the nature of the *** a separate study,the statistical significance of feeding choices was determined by testing a null hypothesis on animal boundary transitions between adjacent pastures using the binomial *** analysis also included compensation for the precision of the GpS sensor,which produced a fuzzy decision boundary.

关键词： agent-based modelling geovisual analytics nitrogen emissions feeding preferences ruminants satellite tracking

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Semiconducting single-walled carbon nanotubes synthesized by S-doping

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Nano-Micro Letters 2009年第1期1卷 9-13页

作者： Z.j.Li L.Wang Y.j.Su p.Liu Y.f.Zhang National Key Laboratory of Nano/Micro fabrication Technology Key Laboratory for Thin Film and Microfabrication of the Ministry of Education Research Institute of Micro/Nanometer Science & Technology Shanghai Jiaotong University

An approach was presented for synthesis of semiconducting single-walled carbon nanotubes(SWNTs) by sulfur(S) doping with the method of graphite arc discharge. Raman spectroscopy, UV-vis-NIR absorption spectroscopy and electronic properties measurements indicated the semconducting properties of the SWNTs samples. Simulant calculation indicated that S doping could induce convertion of metallic SWNTs into semiconducting ones. This strategy may pave a way for the direct synthesis of pure semiconducting SWNTs.

关键词： S-doping Single-wall Carbon nanotubes Semiconducting Arc discharge

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Image cytometric DNA analysis of mucosal biopsies in patients with primary achalasia

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World journal of Gastroenterology 2006年第19期12卷 3020-3025页

作者： I Gockel p K(a|¨)mmerer j Brieger UR Heinrich Wj Mann f Bittinger Vf Eckardt T junginger Department of General and Abdominal Surgery johannes Gutenberg-University Mainz Laboratory of Tumor Biology Department of Otolaryngology Johannes Gutenberg-UniversityMainz Institute of pathology johannes Gutenberg-University Mainz Department of Gastroenterology German Diagnostic Clinic Wiesbaden

AIM： To determine DNA aneuploidy in mucosal biopsies of achalasia patients for subsequent rapid diagnosis. METHODS： Biopsies from the middle third of the esophagus were obtained in 15 patients with achalasia. Immunohistochemical staining was carried out with monoclonal antibodies MIB-1 for Ki67 and pAb 1801 for p53, in addition to the conventional histologic examination for dysplasia. Nuclei of fresh biopsy material were enzymatically and mechanically isolated, and the DNA content was determined with image cytometry after feulgen staining. DNA grading of malignancy was assessed according to Boecking to determine the variability of DNA values noted around the normal diploid peak. further indices measured included the aneuploid rate, and the 5c-, 7c- and 9c-exceeding rate. RESULTS： The histological examination did not demonstrate dysplasia; while MIB-1 （basal） showed a positive reaction in 8/15 achalasia specimens, p53 was negative in all specimens. Image cytometric DNA analysis detected aneuploidy in 4/15 （26.7%） specimens. Samples from 15 patients with squamous cell carcinoma as well as specimens obtained exclusively 2 cm proximal to the tumor served as reference tests. All carcinomas （15/15） as well as 9 of the peritumoral samples （9/15） were aneuploid. The comparison of biopsies from achalasia patients with peritumoral and carcinoma specimens revealed statistically significant differences regarding the aneuploid rate （diploid： p 〈 0.0001; tetraploid： p = 0.001）, grading of malignancy according to Boecking （p 〈 0.0001） and the 5c- （p 〈 0.0001）, 7c-（p 〈 0.0001）, and 9c- （p = 0.0001） exceeding rate with progredient DNA alterations in the respective order. CONCLUSION： The finding that DNA aneuploidy was identified by image cytometry in esophageal specimens of patients with achalasia, which may be due to specific chromosomal alterations presenting as precancerous lesions in 27% of patients, leads us to conclude that image cytometry represents a valuable screening

关键词： Achalasia precancerous epithelial alterations Esophageal carcinoma Image cytometric DNA analysis proliferation marker Ki67 Tumor suppressor gene p53

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