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Journal of Magnesium and Alloys 2022年第9期10卷 2475-2490页

作者： Jong un Lee Sang-Hoon Kim Dong Hee Lee Hyun Ji Kim Young Min Kim Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Agency for Defense Development Daejeon 34186Republic of Korea Implementation research Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

In this study, the bending formability of an extruded Mg–9Al–1Zn–0.3Mn–0.9Ca–0.6Y–0.5 MM(AZXWMM91100, wt%) alloy at room temperature is significantly improved through application of a combined precompression and subsequent annealing(PCA) treatment. As the amount of precompression applied along the extrusion direction(ED)(i.e., the total strain) increases from 4% to 6%, the area fraction of ED-oriented grains of the PCA-treated alloy increases, which consequently causes an improvement in its bending formability because these grains accommodate larger tensile strain along the ED during bending. As the temperature of the subsequent annealing treatment increases from 350 ℃ to 450 ℃, both the area fraction of the ED-oriented grains and the average grain size increase, and the residual dislocation density decreases owing to the promotion of boundary migration and occurrence of the recovery process at higher ***, the bending formability of both the 4%-precompressed and the 6%-precompressed samples increases with an increase in the annealing temperature. However, when the precompressed samples are annealed at 300 ℃, their bending formability is lower than that of the extruded alloy because the dislocations formed by precompression remain even after the subsequent annealing at this temperature.

关键词： Magnesium Extrusion Bending Formability texture

Accelerated precipitation behavior of cast Mg-Al-Zn alloy by grain refinement

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Journal of Materials Science & technology 2018年第2期34卷 265-276页

作者： Sang-Hoon Kim Jong un Lee Ye Jin Kim Jun Ho Bae Bong Sun You Sung Hyuk Park School of Materials Science and Engineering Kyungpook National University Implementation research Division Korea Institute of Materials Science

this study demonstrates that the precipitation behavior of 13-Mg17Al12 phase during aging and the resultant variation in hardness and mechanical properties of cast Mg-Al-Zn alloy are strongly dependent on initial grain size. Grain size reduction accelerates discontinuous precipitation at the early stage of aging treatment by increasing the area fraction of grain boundaries that can act as nucleation sites for discontinuous precipitates （DP）, but it does not influence DP growth rate. Grain refinement also prematurely terminates continuous precipitation because the formation of a large number of DP reduces the amount of AI dissolved in the matrix, which is required for the formation of continuous precipitates （CP）. this promotion of DP formation and early termination of CP formation significantly decrease the peak-aging time to one-third. the enhanced precipitation behavior also leads to an additional hardness improvement in the aged alloy, along with an increase in hardness owing to grain boundary strengthening by grain refinement. the amount of increase in hardness changes with aging time, which is determined by the variation of three variables with aging time： DP fraction difference between refined and nonrefined alloys, hardness difference between DP and matrix, and matrix hardness difference between the two alloys. Grain refinement improves both tensile strength and ductility of the homogenized alloy owing to grain boundary strengthening and suppression of twinning activation, respectively. However, the loss of ductility after peak-aging treatment is greater in the refined alloy because of the larger amount of DP acting as a crack source in this alloy.

关键词： Magnesium Grain refinement Aging Precipitation tensile properties

relative frequency and survival of primary cutaneous lymphomas： a retrospective analysis of 98 patients

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Chinese Medical Journal 2014年第4期127卷 645-650页

作者： Liu J Liu YH Jin HZ Ma DL Qu t Wang t S un QN Yu X Department of Dermatology Peking Union Medical College Hospital Chinese Academy of Medical Sciences Beijing 100730 China Department of Cardiology Fuwai Hospital of Cardiovascular Disease Chinese Academy of Medical Sciences Beijing 100037China

Background the World Health Organization and European Organization for research and treatment of Cancer （WHOEOrtC） classification in 2005 promoted the comparisons of primary cutaneous lymphoma （PCL） subtypes between different *** relative frequency of PCL varied according to *** study aimed to analyze the relative frequency and survival of PCLs in China and to compare the data with the published results from other *** We analyzed 98 patients with PCLs over a 6-year period and reclassified them according to the most recent WHO-EOrtC classification （2005）.Disease-specific survival rate and curves according to specific subtypes such as mycosis fungoides,lymphomatoid papulosis,and primary cutaneous peripheral t-cell lymphoma,unspecified was also *** the relative rate of PCL in China was distinct from those in Western *** study showed a higher frequency of cutaneous t-and NK-cell lymphomas （CtCLs）（94%）,and a lower frequency of cutaneous B-cell lymphomas （CBCLs）（6%）.the 5-year survival rate of the total PCLs was 82%.there was no significant difference in the 5-year survival rate （P 〉0.05 by Log-rank test） between CtCL （80%） and CBCL （100%）.Conclusions the higher percentage of CtCL in China may provide a clue to further study the etiological factors of *** variations in factors such as HLA determinants may play a role in the development of CtCL.

关键词： primary cutaneous lymphomas mycosis fungoides frequency survival rate WHO-EOrtC classification

Evaluation of unconstrained and constrained mathematical functions to model girth growth of rubber trees (Hevea brasiliensis) using young agemeasurements

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Journal of Forestry research 2012年第3期23卷 365-375页

作者： t.r.Chandrasekhar rubber research Institute of India Hevea Breeding Sub StationKadaba-574221DK DistrictKarnatakaIndia

No attempt has been made to date to model growth in girth of rubber tree （Hevea brasiliansis）. We evaluated the few widely used growth functions to identify the most parsimonious and biologically reasonable model for describing the girth growth of young rubber trees based on an incomplete set of young age measurements. Monthly data for girth of immature trees （age 2 to 12 yearsi from two locations were sub- jected to modelling. re-parameterized, unconstrained and constrained growth functions,of richards （rM）, Gompertz （GM） and the monomo- lecular ＇model ^（MM） were fitted to data. Duration of growth was the firsf constraint introduced. In the stagel We attempted a population aver- age （PA） model to capture the trend in growth. the best PA model was fitted as a subject specific （SS） model. We used appropriate error vari- ance-covariance structure to account for correlation due to repeated measurements over time. unconstrainecl functions underestimated the asymptotic maximum that did not reflective carrying capacity of the locations. underestimafions were attributed to the partial set＇ of meas- urements made during the early growth phase of the trees. MM proved superior to rM and GM. In the randomcoefficient models, both Gf and Go appeared to be influenced by tree level effects. Inclusion of diagonal definite positive matrix removed the correlation between random effects. the results were similar at both locations. In the overall assessment MM appeared as the candidate model for studying the girth-age relationships in Hevea trees. Based on the fitted model we conclude that, in Hevea trees, growth rate is maintained at maximum value at to, then decreases until the final state at dG/dt 〉 0, resulting in yield curve with no period of accelerating growth. One physiological explanation is that photosynthetic activity in Hevea trees decreases as girth increases and constructive metabolism is larger than destructive metabolism.

关键词： natural rubber Hevea brasiliensis growth modelling un-constrained functions constrained functions mixed model

Dynamic recrystallization behavior and microstructural evolution of Mg alloy AZ31 through high-speed rolling

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Journal of Materials Science & technology 2018年第10期34卷 1747-1755页

作者： Jeong Hun Lee Jong un Lee Sang-Hoon Kim Seok Weon Song Chong Soo Lee Sung Hyuk Park Ulsan regional Division Korea Institute of Industrial Technology School of Materials Science and Engineering Kyungpook National University technical research Laboratories POSCO Graduate Institute of Ferrous technology Pohang University of Science and Technology

High-speed rolling （HSr） is known to improve the workability of Mg alloys significantly, which makes it possible to impose a large reduction in a single pass without fracture. In the present study, dynamic recrystallization （DrX） behavior and microstructural and textural variations of Mg alloy AZ31 dur-ing a HSr process were investigated by conducting rolling with different imposed reductions in the range of 20%-80% at a high rolling speed of 470 m/min and 400℃. High-strain-rate deformation during HSr suppresses dislocation slips but promotes twinning, which results in the formation of numer-ous twins of several types, i.e., {10-12} extension twins, {10-11} and {10-13} contraction twins, and {10-11}-{10-12} double twins. After twinning, high strain energy is accumulated in twin bands because their crystallographic orientations are favorable for basal slips, leading to subsequent DrX at the twin bands. Accordingly, twinning activation and twinning-induced DrX behavior play crucial roles in accommodating plastic deformation during HSr and in varying microstructure and texture of the high- speed-rolled （HSred） sheets. Area fraction of fine DrXed grains formed at the twin bands increases with increasing rolling reduction, which is attributed to the combined effects of increased strain, strain rate, and deformation temperature and a decreased critical strain for DrX. Size, internal strain, and texture intensity of the DrXed grains are smaller than those of unDrXed grains. therefore, as rolling reduction increases, average grain size, stored internal energy, microstructural inhomogeneity, and basal texture intensity of the HSred sheets gradually decrease owing to an increase in the area fraction of the DrXed grains.

关键词： Magnesium alloy High-speed rolling twinning Dynamic recrystallization Microstructure

Morphotaxonomy and seasonal distribution of planktonic and benthic Prorocentrales in Karachi waters,Pakistan Northern Arabian Sea

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Chinese Journal of Oceanology and Limnology 2013年第2期31卷 267-281页

作者： Sonia MunIr Zaib-un-nisa BUrHAN tahira NAZ P.J.A.SIDDIQUI Steve L.MOrtON Centre of Excellence in marine Biology University of Karachi-75270Pakistan National Oceanic and Atmospheric Administrations 219 Fort Johnson RoadCharleston SC29412USA

Morphotaxonomy and seasonal abundance of dinoflagellates of the genera Prorocentrum and Mesoporos （Prorocentrales） were studied from nutrient-rich waters, Karachi Harbor and the mouth of the Manora Channel, Pakistan during May 2002-July 2003. Using both light and scanning electron microscopy, 13 species of Prorocentrales were identified according to cell shape, size, ornamentation of thecal plates, and architecture of apical platelets, apical pore area, marginal pores, and intercalary bands. P. sigmoides, P. arcuatum, P. scutellum, P. donghaiense, P. balticum, P. minimum, P. emarginatum, P. lima, P. faustiae, and Mesoporos perforatus constitute new records for sindh coast of Pakistan. the most abundant species were P. minimum/P, balticum （4.5x103 cells/L）, P. micans （1.1~103 cells/L）, P. gracile/P, sigmoides （2.5 x 102 cells/L） and P. donghaiense （6.6 x 103 cells/L） at temperatures of 29-31 ~C and salinities of 35-40. Maximum abundance was observed in winter and lower abundance in summer. there was no significant change in the distribution of species between stations except for the benthic species which occurred close to Karachi Harbor waters. Significant positive correlations were observed between Prorocentrum spp. and temperature （r2=0.27） and negative correlations with salinity （r2=-0.32） except for P. minimum and P. emarginatum which has negative correlation with temperature （r2=-0.24） and positive with salinity （r2=0.08, 0.19）. the finding of potential okadaic-acid producing species of benthic Prorocentrum call for monitoring for possible human health problems in this region.

关键词： ecology morphology planktonic/benthic Prorocentrales harmful algae scanning electronaaicroscopy northern Arabian Sea

Forcing ocean model with atmospheric model outputs to simulate storm surge in the Bangladesh coast

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tropical Cyclone research and review 2020年第2期9卷 117-134页

作者： Nabir Mamnun Lucy M.bricheno Md rashed-un-Nabi Nansen-Bangladesh International Centre for Coastal Ocean and Climate StudiesHouse 10Road 16AGulshanDhaka1212Bangladesh Faculty of marine Sciences and Fisheries University of ChittagongChattagram4331Bangladesh National Oceanography Centre Joseph Proudman BuildingBuilding6 Brownlow StreetLiverpoolL35DAUK

tropical cyclones are devastating hazards and have been a major problem for the coastal population of B *** the advancements in atmospheric and oceanic prediction,accurate forecasting of storm surges is of specific interest due to their great potential to inflict loss of life and *** decades,the numerical model based storm surge prediction systems have been an important tool to reduce the loss of human lives and property *** order to improve the accuracy in predicting storm surge and coastal inundation,recent model development efforts tended to include more modeling components,such as meteorology model and surface wave model in storm surge *** this study,we used the outputs of an atmospheric model to force the ocean model for simulating storm surges in the Bay of Bengal with particular focus on the Bangladesh *** ability of the modeling system was investigated simulating water levels in the Bangladesh coast of two tropical cyclones Sidr(2007)and Aila(2009).the effectiveness of the model was verified through comparing the obtained computational outputs against tide gauge *** cyclone tracks and intensities reproduced by the atmospheric model were reasonable,though the model had a tendency to overestimate the cyclone intensity during peaks and also close to *** water levels are reproduced fairly well by the ocean model,although errors still *** root mean square errors in water level at different gauges range from 0.277 to 0.419 m with coefficient of correlation(r^2)between 0.64 and 0.97 in case of Sidr and0.209-0.581 m with r^20.62 to 0.98 for *** overall coupled modeling system is found to be useful with reasonable accuracy and precision,though there are spaces for ***-resolution modeling approaches are recommended to gain more skills.

关键词： tropical cyclone Storm surge One-way coupling Bay of bengal

recent research progress on magnesium alloys in Korea:A review

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Journal of Magnesium and Alloys 2023年第10期11卷 3545-3584页

作者： Sung Hyuk Park Ye Jin Kim Hyun Ji Kim Sang-Cheol Jin Jong un Lee Alexander Komissarov Kwang Seon Shin School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Laboratory of Hybrid Nanostructured Materials National University of Science and TechnologyMoscow 119049Russia Laboratory of Medical Bioresorption and Bioresistance Moscow State University of Medicine and DentistryMoscow 127473Russia Magnesium technology Innovation Center School of Materials Science and EngineeringSeoul National UniversitySeoul 08826Republic of Korea

this review highlights the recent advancements in Mg research in South Korea with a prime focus on high-speed-extrudable Mg–Bi-based alloys for high productivity and strength,innovative techniques utilizing{10–12}twinning for improved mechanical properties,and alloying and processing methods for enhanced corrosion ***-alloyed Mg–Bi-based alloys possess thermally stableα-Mg matrix and secondary phase,which ensures high-speed extrusion of these alloys at elevated temperatures without hot ***,they exhibit outstanding extrudability with a maximum extrusion speed of up to 70 m/***,their high alloying contents offer excellent strength even after high-speed extrusion through strong solid solution hardening and particle hardening effects,making them suitable for high-performance extruded Mg *** pre-twinning process utilizing{10–12}twinning and the combined process of pre-twinning and subsequent annealing have shown promise in controlling microstructure and texture of wrought Mg alloys and thus enhancing their mechanical *** pre-twinning process enhances tensile strength,fatigue properties,and age-hardening rate of Mg ***,the combined processes of pre-twinning and subsequent annealing considerably improve their ductility,stretch formability,bending formability,and damping *** have been made to improve the corrosion resistance of Mg alloys through alloying additions,process treatments,and surface *** elements like Ca,Sc,and Sm alter the microstructural features(such as secondary phases and grain size)that affect the corrosion *** treatments such as multidirectional forging,screw rolling,and pulse electron beam can also improve the corrosion resistance by refining the ***,advanced surface coating technologies can create durable and corrosion-resistant layers for effectively protecting the Mg *** these research activities conducted

关键词： South Korea Mg–Bi alloys {10–12}twinning Corrosion Mechanical properties

AN APPrOACH IN MODELING tWO-DIMENSIONAL PArtIALLY CAVItAtING FLOW

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Journal of Hydrodynamics 2002年第1期14卷 45-51页

作者： Wu Lei, Lu Chuan-jing, Xue Lei-ping (Department of Engineering Mechanics, Shanghai Jiaotong un iversity, Shanghai 200240, China) Dept. of Eng. Mech. Shanghai Jiaotong Univ. Shanghai 200240 China

An approach of modeling viscosity, unsteady partially cavitating flows around lifting bodies is presented. By em ploying an one-fluid Navier-Stokers solver, the algorithm is proved to be able to handle two-dimensional laminar cavitating flows at moderate reynolds numbe r. Based on the state equation of water-vapor mixture, the constructive relatio ns of densities and pressures are established. to numerically simulate the cavi ty wall, different pseudo transition of density models are presumed. the finite-volume method is adopted and the algorithm can be extended to three-dimensional cavitating flows.

关键词： cavitating flow two-phase flow

Approach for Grid Connected PV Management:Advance Solar Prediction and Enhancement of Voltage Stability margin Using FACtS Device

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Journal of Electronic Science and technology 2020年第4期18卷 367-377页

作者： Md.Masum Howlader Mohammad rokonuzzaman Md tanbhir Hoq Aziz un Nur Ibn Saif MD Shahrukh Adnan Khan Mahfuj Howlader Department of Electrical and Electronic Engineering University of Asia PacificDhaka 1205 tyndall National Institute University College CorkCork T12 K8AF School of Science and Engineering Canadian University of BangladesDhaka 1212 Department of Computer Science and Engineering University of DhakaDhaka 1000

the uncertainty in solar energy is different from conventional,dispatchable generation fuels and difficult to incorporate into the standard system operating *** the first part of this work,the machine learning algorithm is used to train models based on solar irradiance data and different meteorological weather information to predict the solar irradiance for different cities to validate the forecasting ***,the intermittent and inertialess nature of photovoltaic(PV)systems can produce significant power oscillations that can cause significant problems with dynamic stability of the power system and also limit the penetration capacity of PV into the *** the second part,it is shown that the residue-based power oscillation damping(POD)controller obviously improves the inter-area oscillation *** validity and effectiveness of the proposed controller are demonstrated on the three-machine two-area test system that combines the conventional synchronous generator and flexible alternating current transmission systems(FACtS)device using *** report overall puts an in-depth analysis with regard to the challenges of solar resources with integrating,planning,operating,and particularly the stability of the rest of the power grid,including existing generation resources,customer requirements,and the transmission system itself that will lead to an improved decision making in resource allocations and grid stability.

关键词： renewable energy(rE) support vector regression thyristor controlled series capacitor