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Microstructural evolution and mechanical properties of Mg-9.8Gd-2.7Y-0.4Zr alloy produced by repetitive upsetting

Journal of Materials Science & Technology 2018年第7期34卷 1067-1075页

作者： H.Zhou H.Y.Ning X.l.Ma d.d.Yin l.R.Xiao X.C.Sha Y.d.Yu Q.d.Wang Y.S.li Nano and Heterogeneous Materials Center School of Materials and EngineeringNanjing University of Science and TechnologyNanjing210094China Institute of Microstructure and Property of Advanced Materials Beijing University of TechnologyBeijing 100124China School of Mechanical and Electrical Engineering Heilongjiang Institute of TechnologyHeilongjiang 150050China School of Materials Science and Engineering Harbin University of Science and TechnologyHarbin 150040China department of Materials Science&Engineering North Carolina State UniversityRaleighNC 27695USA Key laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengduSichuan 610031China National Engineering Research Center of light Alloys Net Forming and State Key Laboratory of Metal Matrix CompositeShanghai Jiao Tong University200240 ShanghaiChina

A newly developed severe plastic deformation （SPd） technique, i.e. repetitive upsetting （RU）, is employed to improve the strength and ductility of a Mg-Gd-Y-Zr alloy. during the RU processing, dynamic recrystallization occurs in the Mg alloy, which leads to a significant grain refinement from 11.2 p.m to 2.8 μm. The yield strength （YS）, ultimate tensile strength （UTS） and elongation increase simultaneously with increasing RU passes. The microstructural evolution is affected by processing temperatures. dynamic recrystallization prevails at low temperatures, while dynamic recovery is the main effect factor at high temperatures. Texture characteristics gradually become random during multiple passes of RU processing, which reduces the tension-compression asymmetry of the Mg-Gd-Y-Zr alloy. 2018 Published by Elsevier ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

关键词： Severe plastic deformation (SPd) Repetitive upsetting (RU) Mg-RE alloy Mechanical properties

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Improved speciation of dissolved organic nitrogen in natural waters: amide hydrolysis with fluorescence derivatization

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Journal of Environmental Sciences 2008年第10期20卷 1273-1280页

作者： Ryan l.Fimmen Tamara d.Trouts daniel d.Richter Jr. dharni Vasudevan School of Earth Sciences The Ohio State University 125 S.Oval MallColumbus OH 43210 USA.Nicholas School of the Environment and Earth Sciences Duke University Durham NC 27708 USA School of Earth Sciences The Ohio State University 125 S.Oval MallColumbus OH 43210 USA Nicholas School of the Environment and Earth Sciences Duke UniversityDurham NC 27708 USA. Nicholas School of the Environment and Earth Sciences Duke UniversityDurham NC 27708 USA.Department of Chemistry Bowdoin CollegeBrunswick ME 04011 USA

The objective of this study was to improve primary-amine nitrogen (1°-N) quantification in dissolved organic matter (dOM) originating from natural waters where inorganic forms of N, which may cause analytical interference, are commonly encountered. Efforts were targeted at elucidating organic-N structural criteria influencing the response of organic amines to known colorimetric and fluorescent reagents and exploring the use of divalent metal-assisted amide hydrolysis in combination with fluorescence analyse...

关键词： dissolved organic matter/nitrogen (dOM/dON) o-phthaldialdehyde fluorescamine ninhydrin amino acids amide hydrolysis peptides

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different diffusion Behavior of Cu and Ni Undergoing liquidesolid Electromigration

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Journal of Materials Science & Technology 2014年第12期30卷 1235-1242页

作者： M.l.Huang Z.J.Zhang H.T.Ma l.d.Chen Electronic Packaging Materials laboratory School of Materials Science & Engineering Dalian University of Technology IC Packaging department Xi'an Institute of Microelectronic Technology

The diffusion behavior of Cu and Ni atoms undergoing liquidesolid electromigration（l-S EM） was investigated using Cu/Sn/Ni interconnects under a current density of 5.0 103A/cm2 at 250℃. The flowing direction of electrons significantly influences the cross-solder interaction of Cu and Ni atoms, i.e., under downwind diffusion, both Cu and Ni atoms can diffuse to the opposite interfaces; while under upwind diffusion,Cu atoms but not Ni atoms can diffuse to the opposite interface. When electrons flow from the Cu to the Ni, only Cu atoms diffuse to the opposite anode Ni interface, resulting in the transformation of interfacial intermetallic compound（IMC） from Ni3Sn4into（Cu,Ni）6Sn5and further into [（Cu,Ni）6Sn5t Cu6Sn5], while no Ni atoms diffuse to the opposite cathode Cu interface and thus the interfacial Cu6Sn5 *** electrons flow from the Ni to the Cu, both Cu and Ni atoms diffuse to the opposite interfaces,resulting in the interfacial IMC transformation from initial Cu6Sn5into（Cu,Ni）6Sn5and further into[（Cu,Ni）6Sn5t（Ni,Cu）3Sn4] at the anode Cu interface while that from initial Ni3Sn4into（Cu,Ni）6Sn5and further into（Ni,Cu）3Sn4at the cathode Ni interface. It is more damaging with electrons flowing from the Cu to the Ni than the other way.

关键词： Cu/Sn/Ni Electromigration Cross-solder interaction Interfacial reaction diffusion

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Mechanical properties of gas hydrate-bearing sediments during hydrate dissociation

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Acta Mechanica Sinica 2018年第2期34卷 266-274页

作者： X.H.Zhang d.S.luo X.B.lu l.l.liu C.l.liu Institute of Mechanics Chinese Academy of SciencesBeijing 100190China College of Engineering University of Chinese Academy of SciencesBeijing 100049China Key laboratory of Gas Hydrate Ministry of Land and ResourcesQingdao 266071China Qingdao Institute of Marine Geology Qingdao 266071China

The changes in the mechanical properties of gas hydrate-bearing sediments(GHBS) induced by gas hydrate(GH) dissociation are essential to the evaluation of GH exploration and stratum instabilities. Previous studies present substantial mechanical data and constitutive models for GHBS at a given GH saturation under the non-dissociated condition. In this paper, GHBS was formed by the gas saturated method, GH was dissociated by depressurization until the GH saturation reached different dissociation degrees. The stress–strain curves were measured using triaxial tests at a same pore gas pressure and different confining pressures. The results show that the shear strength decreases progressively by 30%–90% of the initial value with GH dissociation, and the modulus decreases by 50% –75%. Simplified relationships for the modulus, cohesion, and internal friction angle with GH dissociated saturation were presented.

关键词： Gas hydrate-bearing sediments dissociation Mechanical properties Shear strength Triaxial test

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A novel approach to enhance decrepitation temperature and reducibility of ultrafine iron ore concentrate pellets

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Journal of Iron and Steel Research International 2024年第11期31卷 2622-2632页

作者： B.l.Wen Z.H.Fan J.X.li d.l.liu J.l.Yang School of Metallurgical Engineering Anhui University of TechnologyMa'anshan 243032AnhuiChina Jianlong(liaoning)Energy Saving and Environmental Protection

Utilizing ultrafine iron ore concentrate for pellet production can expand domestic iron ore resources in China and promote the utilization of low-grade ***,a challenge arises with the low decrepitation temperature and reducibility in the preparation process of ultrafine iron ore concentrate *** address the challenge,a novel approach was proposed,which incorporated straw powder as an additive to enhance pellet porosity,thereby improving the decrepitation temper-ature and reducibility of ultrafine iron ore concentrate *** effect of varying proportions of straw powder(0.0-2.0%)on the characteristics of ultrafine iron ore concentrate pellets was *** indicate that at a 2.0%straw powder ratio,pellet decrepitation temperature notably rises from 380 to 540℃,while the reducibility index escalates from 25.7%to 48.1%.Nevertheless,the addition of straw powder results in diminished drop strength,compressive strength of green pellets,and cold crushing strength of fired *** addition,enhanced pellet reducibility leads to exacerbated reduction swelling index and reduction degradation *** these effects,all parameters remain within an acceptable range.

关键词： Ultrafine iron ore concentrate:Straw powder Green pellet quality decrepitation temperature:Metallurgical property

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Subpicosecond pulses in a self-starting mode-locked semiconductor-based figure-of-eight fiber laser

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Photonics Research 2017年第1期5卷 37-40页

作者： d.Chaparro l.Furfaro Salvador Balle department de Física Universitat de les Illes BalearsCtra.de Valldemossa km.7’5E-07122 Palma de MallorcaSpain FEMTO-ST Universitédu Franche-Comté15B Avenue des Montboucons25030 Besancon CEDEXFrance Institut Mediterrani d’Estudis Avancats(CSIC-UIB) C/Miquel Marqués 21E-07190 EsporlesSpain

We have experimentally studied the mode-locking dynamics of a polarization-maintaining figure-of-eight laser which has a semiconductor optical amplifier as gain medium. Self-starting mode-locking at the fundamental repetition rate of 18 MHz is obtained at the lasing threshold, and further increasing the bias current leads to the progressive emission of additional optical pulses in each round trip and eventually to mode-locked emission at increasingly high harmonics of the fundamental repetition rate, up to 2.45 GHz. The intensity autocorrelation of the amplified mode-locked pulses has a full width at half-maximum duration of 382 fs, which corresponds to a pulse duration of 247 fs.

关键词： mode Subpicosecond pulses in a self-starting mode-locked semiconductor-based figure-of-eight fiber laser

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Maternal effects, malaria infections and the badge size of the house sparrow

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Chinese Birds 2015年第4期6卷 215-224页

作者： Philip l.G.Birget Stephen d.larcombe St Peter’s College University of Oxford Institute of Evolutionary Biology University of Edinburgh Edward Grey Institute of Field Ornithology University of Oxford Centre de Recherche de la Tour du Valat Jesus College University of Oxford Institute of Biodiversity Animal Health and Comparative Medicine University of Glasgow

Background: The evolution of sexual signals is not only determined by immediate sexual selection but also by selection arising from the environment and the interaction with developmental *** this study we aimed to investigate how the badge size of male house sparrows(Passer domesticus) is correlated to avian malaria infections as well as to prenatal testosterone exposure,measured as the 2d:4d digit *** rationale behind this study is that the immunosuppressive effect of maternal testosterone deposition combined with the fitness cost imposed by parasites may cause important trade-offs to the development of secondary sexual ***: Assuming that vector abundance is a key variable associated with infection risk by avian malaria,we caught adult male sparrows from eight different populations in the Camargue,France,four of which were located in a vector-controlled area,and the other four in an untreated *** each bird we measured its badge size,digit ratio and took blood to determine its infections *** used PCR to identify the malaria parasite species and strain that caused the ***: Contrary to our expectation,prevalence of disease did not differ across the vector-treatment regions,with around 80 % of birds being infected in both areas,and those infections were caused largely by a single strain,Plasmodium relictum *** infected birds had a badge size not significantly different from uninfected males,there was a condition-dependent association between badge size,infection status and maternal testosterone ***: This study illustrates that the complexity of temporal and ecological dimensions makes the relationships between disease,testosterone-related traits and secondary sexual signals that have been previously reported less general than thought.

关键词： Avian malaria digit ratio Passer domesticus Sexual signals

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Occupational injuries and burn out among orthopedic oncology surgeons

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World Journal of Orthopedics 2022年第12期13卷 1056-1063页

作者： Abdulrahman M Alaseem Robert E turcotte Nathalie Ste-Marie Mohammad M Alzahrani Saad M Alqahtani Krista A Goulding department of Orthopedic Surgery College of MedicineKing Saud UniversityRiyadh 12372Saudi Arabia department of Orthopedic Surgery McGill University Health CentreMontreal H4A3J1Canada department of Orthopedic Surgery College of MedicineImam Abdulrahman Bin Faisal universityDammam 34212Saudi Arabia department of Orthopaedic Surgery Mayo ClinicPhoenixArizona 85054USA

BACKGROUNd Orthopedic oncology surgeons commonly engage in prolonged and complex surgical *** types of surgeries increase the risk of physical and psychological stressors,which may in turn make these physicians prone to workrelated occupational *** The aim of this study was to explore in orthopedic oncologists,the prevalence of work-related physical injuries and psychological *** A modified version of the physical discomfort survey was developed to assess occupational injuries among orthopedic oncology surgeon members of the Musculoskeletal Tumor Society,the Canadian Orthopedic Oncology Society and European Musculoskeletal Oncology *** survey was sent by email,and it explored musculoskeletal complaints,psychological disturbances,treatment required for these complaints and the requirement of time off *** A total of 67 surgeon responses were collected.A high number of orthopedic oncologists(84%)reported an occupational *** back pain(39%)was the most prevalent musculoskeletal condition,followed by lumbar disk herniation(16%),shoulder tendinitis(15%)and lateral epicondylitis(13%).Of the cohort,46%required surgery and 31%required time off work due to their ***-three respondents reported a psychological ***(27%),anxiety(20%)and insomnia(20%)were the most commonly *** required off work due to injury was associated with old age and years in *** Orthopedic oncology surgeons report a high prevalence of work-related *** back related injury and burnout were the most reported *** operative room ergonomics and prevention of stress related to the work environment should be areas to explore in upcoming research.

关键词： Orthopedic oncology Surgeons Occupational Musculoskeletal Injuries

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distribution and Assessment of Soil and land degradation in Subtropical China—A Case Study of the dongxi River Basin, Fujian Province *1

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Pedosphere 1998年第3期8卷 201-210页

作者： PUlIJIE d．l．HIGGITT 等 departementofGeography NanjingUniversityNanjing210093（China） departementofGeography UniversityofDurh

Some alternative methods for estimating soil erosion rates rapidly were used to elucidate the relationship between the land use types and land degradation. The 137 Cs content, magnetic susceptibility, aggregate stability, and soil properties were studied in the dongxi River Basin, a mountainous area of western Fujian. A plot of 137 Cs inventory (Y) against slope angle (X) shows a strong inverse log log relationship ( r = -0.83 ), indicating that much more soil erosion occurs on steeper slopes. Average soil loss (in thickness of top soil per year) in the past 30 years for arable slope crest, arable slopes and tea plantation slopes are 1.6 , 10.4 and 8.0 mm year -1 respectively. The surface layer enrichment factor of magnetic susceptibility (Y) in soil also shows an inverse log log relationship ( r =-0.63), indicating a similar tendency with the relationship between the 137 Cs inventory (Y) against slope angle (X). The physical and chemical properties of soils among different land use types show different degraded characteristics at different significant levels.

关键词： Cs technique magnetic susceptibility soil and land degradation subtropical environment

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Species in lichen-forming fungi:balancing between conceptual and practical considerations,and between phenotype and phylogenomics

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Fungal diversity 2021年第4期109卷 99-154页

作者： Robert lücking Steven d.leavitt david l.Hawksworth Botanischer Garten Und Botanisches Museum Freie Universität BerlinKönigin-Luise-Str.6-814195 BerlinGermany department of Biology Brigham Young University4102 Life Science BuildingProvoUT 84602USA M.l.Bean life Science Museum Brigham Young University1115 MLBMProvoUT 84602USA department of life Sciences The Natural History MuseumLondon SW75BDUK Comparative Plant and Fungal Biology Royal Botanic GardensKewRichmond TW92ABSurreyUK

lichens are symbiotic associations resulting from interactions among fungi(primary and secondary mycobionts),algae and/or cyanobacteria(primary and secondary photobionts),and specific elements of the bacterial microbiome associated with the lichen *** question of what is a species,both concerning the lichen as a whole and its main fungal component,the primary mycobiont,has faced many challenges throughout history and has reached new dimensions with the advent of molecular phylogenetics and *** this paper,we briefly revise the definition of lichens and the scientific and vernacular naming conventions,concluding that the scientific,latinized name usually associated with lichens invariably refers to the primary mycobiont,whereas the vernacular name encompasses the entire *** the same lichen mycobiont may produce different phenotypes when associating with different photobionts or growing in axenic culture,this discrete variation does not warrant the application of different scientific names,but must follow the principle"one fungus=one name".Instead,broadly agreed informal designations should be used for such discrete morphologies,such as chloromorph and cyanomorph for lichens formed by the same mycobiont but with either green algae or *** taxonomic recognition of species in lichen-forming fungi is not different from other fungi and conceptual and nomenclatural approaches follow the same *** identify a number of current challenges and provide recommendations to address *** delimitation in lichen-forming fungi should not be tailored to particular species concepts but instead be derived from empirical evidence,applying one or several of the following principles in what we call the lPR approach:lineage(l)coherence ***(phylogenetic component),phenotype(P)coherence ***(morphological component),and/or reproductive(R)compatibility ***(biological component).Species hypotheses can be e

关键词： Alpha taxonomy Beta taxonomy Biological species concept Cora Cryptic speciation Fungal farmers Gamma taxonomy Infraspecies lichens as ecosystems Machine learning Morphological species concept One fungus=one name Photomorph Phylogenetic species concept Species pair concept Thamnolia

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