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the Impact of topography on Social Factors,a Case Study of Montenegro

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Journal of Mountain Science 2014年第1期11卷 131-141页

作者： tELBISZ tamás BOttLIK Zsolt MARI László KOSZEGI Margit Department of physical Geography Eotvos University Department of Regional Science Eotvos University

Relationships between environmental and social factors have long been studied by ***,GIS-aided statistical analysis provides new tools to explore these *** order to detect the impact of topography on social factors,we selected the country of Montenegro as a case example due to its high topographic *** compared the spatial pattern of population,settlements and ethnic minorities to physical geographic factors,especially to topography,but lithology and land cover data were also taken into *** found that certain factors are closely correlated,*** settlement density linearly decreases with elevation,while the characteristic settlement area shows an exponential increase *** population density is not related to absolute elevation,but it is in close correlation with height(*** relative to the local minimum).population change and illiteracy are also topography-related social *** the contrary,the variable ethnic pattern of Montenegro is influenced by historical,political and economic effects rather than by environmental factors or topographic *** a conclusion we state that in the scale of a country or a region,the environment can strongly impact some social factors.

关键词： human-environment relations Dinarides GIS Settlements population Ethnic groups

Grain size and temperature effect on the tensile behavior and deformation mechanisms of non-equiatomic Fe(41)Mn(25)Ni(24)Co8Cr2high entropy alloy

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Journal of Materials Science & technology 2020年第7期42卷 190-202页

作者： h.t.Jeong W.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul121-791Republic of Korea

the effect of the grain size on the tensile properties and deformation mechanisms of a nonequiatomic Fe(41)Mn(25)Ni(24)Co8 Cr2 high-entropy alloy was studied in the temperature range between 298 and 1173 K by preparing the samples with three different grain sizes through severe plastic deformation and subsequent annealing:ultrafine(sub)grain size(≤0.5μm),8.1μm and 590.2μ*** the temperature between 298 and773 K,the material with the large grain size of 590.2μm exhibited the largest tensile ductility(57%-82%)due to its high strain hardening associated with mechanical twinning,but it exhibited the lowest strength due to its large grain *** material with the ultrafine(sub)grain size exhibited the lowest tensile ductility(3%-7%)due to a greatly reduced strain hardening ability after severe plastic deformation,but it exhibited the highest strength due to the dislocation strengthening and grain refinement *** tensile testing at temperatures above 973 K,recrystallization occurred in the material with the ultrafine(sub)grains during the sample heating and holding stage,leading to the formation of fine and equiaxed grains with the sizes of 6.8-13.5μ*** deformation behavior of the Fe(41)Mn(25)Ni(24)Co8 Cr2 with different grain sizes in the high temperature range between 973 and 1173 K,where pseudosteady-state flow was attained in the stress-strain curves,could be explained by considering the simultaneous contribution of grain boundary sliding and dislocation-climb creep to total plastic *** activation energies for plastic flow for the materials with different grain sizes were similar as^199 kJ/*** predicting the deformation mechanism,it was important to consider the change in grain size by rapid grain growth or recrystallization during the sample heating and holding stage because grain boundary sliding is a grain-size-dependent deformation *** sample with the ultrafine(sub)grains exhibited the large tensile elongations of 30%-85%due to it

关键词： high entropy alloys Grain size high temperature deformation mechanism tensile behavior Grain boundary sliding

Effects of grain size and Al addition on the activation volume and strain-rate sensitivity of CoCrFeMnNi high-entropy alloy

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Journal of Materials Science & technology 2023年第12期143卷 242-252页

作者： h.t.Jeong W.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul121-791Republic of Korea

the activation volume(V∗)and strain-rate sensitivity exponent(m)of CoCrFeMnNi and Al_(0.5)CoCrFeMnNi high entropy alloys(hEAs)with various grain sizes(ranging between 2.4 and 356μm)were measured at different strain rates and strain levels at room *** the strain rate decreased,the plastic strain decreased,and the grain size increased,V∗*** enhanced solid-solution strengthening by addition of aluminum decreased V∗.the hassen plot was modified to capture the grain-size depen-dence of V∗by considering the grain-size dependence of the dislocation *** the plastic strain increased,the strain rate decreased,and the grain size decreased,m *** behavior of m could be quantitatively predicted by using equations derived for the grain-size-dependent V∗and flow *** difference in the grain-size dependence of m between conventional face centered cubic(FCC)metals and FCC hEAs over the nanograin size range could not be explained in terms of a relatively large hall-petch slope of the FCC hEAs compared with that of the FCC conventional metals,but was explainable in terms of a substantially higher probability of activation of grain-boundary diffusion-controlled grain-boundary-sliding mechanism at nanograin sizes in the FCC conventional metals than in the FCC hEAs.

关键词： Grain size high entropy alloys Activation volume Strain-rate sensitivity Solid solution

GRB 170817A: a short GRB seen off-axis

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Research in Astronomy and Astrophysics 2018年第4期18卷 69-76页

作者： Xin-Bo he pak-hin thomas tam Rong-Feng Shen School of physics and Astronomy Sun Yat-sen University

the angular distribution of gamma-ray burst（GRB）jets is not yet *** observed luminosity of GRB 170817A is the lowest among all known short GRBs,which is best explained by the fact that our line of sight is outside of the jet opening angle,θ_（obs）〉θ_j,whereθ_（obs） is the angle between our line of sight and the jet *** inferred by gravitational wave observations,as well as radio and X-ray afterglow modeling of GRB 170817A,it is likely that θ_（obs）~20°–28°.In this work,we quantitatively consider two scenarios of angular energy distribution of GRB ejecta：a top-hat jet and a structured jet with a power law index *** the top-hat jet model,we get a large θ_j（e.g.,θ_j〉10°）,a rather high local （i.e., z 〈 0.01） short GRB rate ~8–15×10~3 Gpc^（-3）yr~（-1（（estimated to be 90~1850 Gpc^（-3）yr^（-1） in Fong et al.）and an extremely high（on-axis,V（~500 ke V for a typical short GRB）.For the structured jet model,we use θ_（obs） to give limits on s and θ_j for typical on-axis luminosity of a short GRB（e.g.,10^（49）erg s（-1） 1051erg s（-1））,and a low on-axis luminosity case（e.g.,1049erg s（-1））gives more reasonable values of *** structured jet model is more feasible for GRB170817A than the top-hat jet model due to the rather high local short GRB rate,and the extremely high on-axis E_（peak,0） almost rules out the top-hat jet *** 170817A is likely a low on-axis luminosity GRB（1049erg s（-1））with a structured jet.

关键词： short gamma-ray burst individual(GRB 170817A) — gravitational wave

Complications in children with percutaneous endoscopic gastrostomy (pEG) placement

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World Journal of pediatrics 2019年第1期15卷 12-16页

作者： Brigitta Balogh tamás Kovács Amulya Kumar Saxena Division of pediatric Surgery Department of PediatricsUniversity of SzegedKorányi fasor 14-15Szeged 6725Hungary Department of pediatric Surgery Chelsea Children's HospitalChelsea and Westminster NHS Fdn TrustImperial College LondonLondonUK

Introduction the aim of this study was to analyze the complication rates and mortality in association with different operative techniques of percutaneous endoscopic gastrostomy (pEG),age,underlying diseases and other risk ***,analysis of the indications of pEG insertion and the underlying comorbidities was also *** this study performs a literature analysis of pEG-related complications in *** was searched on pubMed(R) (1994-2017) using terms 'percutaneous endoscopic gastrostomy','complications','mortality' and 'children'.Results Eighteen articles with 4631 patients were *** mean age was 3 years (0-26 years).Operative techniques were:pull technique in 3507 (75.7%),1 stage pEG insertion in 449 (9.7%),introducer technique in 435 (9.4%),image-guided technique in 195 (4.2%) and laparoscopic-assisted pEG in 45 (1.6%).Most frequent indications for pEG insertion were dysphagia (n =859,32.6%),failure to thrive (n =723,27.5%) and feeding difficulties (n =459,17.4%).Minor complications developed in n 1518 patients (33%),including granulation (n =478,10.3%),local infection (n =384,8.3%) and leakage (n =279,6%).In 464 (10%) patients,major complications occurred;the most common were systemic infection (n =163,3.5%)and cellulitis (n =47,1%).Severe complication like perforation occurred in less than 0.3%.patients with lethal outcomes (n =7,0.15%) had severe comorbidities;and the cause of mortality was sepsis in all *** or young age did not affect complication *** with ventriculoperitoneal (Vp) shunt had higher risk of major *** high-risk patients,laparoscopic-assisted pEG insertion had less major and severe complication than traditional pull *** pEG is a safe operative technique;although minor complications are relatively common and occur in up to 1/3 of patients,there is a fairly low rate of severe ***-thirds of pEG patients have at least one ***

关键词： Children Complications percutaneous endoscopic gastrostomy

Low-temperature conformal vacuum deposition of OLED devices using close-space sublimation

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Journal of Semiconductors 2023年第9期44卷 62-67页

作者： Bryan Siu ting tam Shou-Cheng Dong Ching W.tang State Key Laboratory of Advanced Displays and Optoelectronics technologies Department of Electronic and Computer EngineeringThe Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina Institute for Advanced Study The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina

Close-space sublimation(CSS)has been demonstrated as an alternative vacuum deposition technique for fabricating organic light-emitting diodes(OLEDs).CSS utilizes a planar donor plate pre-coated with organic thin films as an area source to rapidly transfer the donor film to a device substrate at temperatures below 200℃.CSS is also conformal and capable of depositing on odd-shaped substrates using flexible donor *** evaporation behaviors of organic donor films under CSS were fully characterized using model OLED materials and CSS-deposited films exhibited comparable device performances in an OLED stack to films deposited by conventional point *** low temperature and conformal nature of CSS,along with its high material utilization and short process time,make it a promising method for fabricating flexible OLED displays.

关键词： close-space sublimation OLED thin film low temperature vacuum deposition

Effect of roll speed ratio on the texture and microstructural evolution of an FCC high-entropy alloy during differential speed rolling

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Journal of Materials Science & technology 2022年第16期111卷 152-166页

作者： h.t.Jeong W.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

A very coarse-grained(335μm)Fe_(41)Mn_(25)Ni_(24)Co_(8)Cr_(2)high-entropy alloy with a single FCC phase was cold rolling to a 80%reduction in thickness using the differential speed rolling technique with various speed ratios(SRs)ranging between 1 and *** the SR was increased,the volume fraction of the region of high-density micro-shear bands increased to accommodate the higher shear *** SR=4,the entire thickness of the sheet was covered with micro-shear bands,and ultrafine(sub)grains with a size of1.4μm were uniformly formed along the shear bands.A continuous dynamic recrystallization(CDRX)mechanism occurred during rolling,and a higher SR accelerated the CDRX *** conventional rolling(at SR=1),a brass{110}orientation texture with minor components of S{123}and Cu{112}orientations *** higher SRs,shear texture developed as the main type,while the development of rolling texture was *** microstructure at SR=4 obtained after annealing at973 K showed a fully recrystallized microstructure composed of a five times smaller grain size(4μm)with a higher intensity ofγfiber texture compared with that prepared by conventional *** samples processed with high SRs exhibited better tensile properties compared with the conventionally rolled sample in terms of strength and ductility after *** current results demonstrate that by using differential speed rolling with a high SR,one can achieve a significantly finer and more homogeneous microstructure,stronger shear texture,and superior tensile mechanical properties for an FCC high-entropy alloy compared to that obtained by conventional *** strength of the as-rolled and annealed samples was quantitatively explained by considering the contribution of grain size and dislocation density to strengthening.

关键词： high entropy alloys Differential speed rolling texture Grain refinement Strength Severe plastic deformation

Microstructure tailoring of Al_(0.5)CoCrFeMnNi to achieve high strength and high uniform strain using severe plastic deformation and an annealing treatment

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Journal of Materials Science & technology 2021年第12期71卷 228-240页

作者： h.t.Jeong W.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

Ultrafine-grained alloys fabricated by severe plastic deformation(SpD)have high strength but often poor uniform *** via high-ratio differential speed rolling(hRDSR)followed by an annealing treatment was applied to Al_(0.5)CoCrFeMnNi to design the microstructure from which both high strength and high uniform strain can be *** optimized microstructure was composed of an ultrafine-grained FCC matrix(1.7-2μm)with a high fraction of high-angle grain boundaries(61%-66%)and ultrafine BCC particles(with a size of 0.6-1μm and a volume fraction of8%-9.3%)distributed uniformly at the grain boundaries of the FCC *** the severely plastically deformed microstructure,the nucleation kinetics of the BCC phase was *** static recrystallization(CSRX)took place during the annealing process at 1273 *** of the BCC phase particles occurring concurrently with CSRX effectively retarded the grain growth of the FCC *** precipitation of the hard and brittleσphase was,however,*** annealed sample processed by hRDSR with the optimized microstructure exhibited a high tensile strength of over 1 Gpa with a good uniform elongation of 14%-20%.these tensile properties are comparable to those of transformation-induced plasticity *** mechanisms of the severely plastically deformed alloy before and after annealing were identified,and each strengthening mechanism contribution was *** calculated results matched well with the experimental results.

关键词： high entropy alloys Severe plastic deformation Uniform ductility high strength Dual phase Annealing

Effect of Active Mineral Filler on Rutting performance and Fatigue properties of Granite Asphalt Concrete

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武汉理工大学学报 2010年第17期32卷 55-58,82页

作者： ZhU Z h WU S p LI W t hUANG X Key Laboratory of Silicate Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China hubei provincial Building Science Research & Design Institute Wuhan 430070China

Granite is well known as an acid aggregate. An active mineral filler produced in the laboratory is first used as an anti-stripping filler in the granite asphalt concrete. Four aggregate gradations were chosen in this study,and the effects of the active mineral filler and aggregates on the rutting resistance performance and fatigue properties of granite asphalt concrete were investigated by means of rutting test and four-point bending fatigue test. the results indicate that the dynamic stability of granite asphalt concrete increase significantly with the addition of active mineral filler and the fatigue properties can also be improved especially at lower strain level. Meanwhile,the results demonstrate that granite asphalt concrete has better rutting resistance performance and fatigue properties than limestone asphalt concrete.

关键词： granite asphalt concrete active mineral filler rutting resistance performance fatigue properties