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Variability and trends of near-surface wind speed over the Tibetan Plateau:The role played by the westerly and Asian monsoon

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Advances in Climate Change Research 2024年第3期15卷 525-536页

作者： Gang-Feng ZHANG Cesar AZORIN-MOLINA Deliang CHEN Tim RMCVICAR Jose AGUIJARRO Kai-Qiang DENG Lorenzo MINOLA Jaeyeon LEE seok-woo son Heng MA Pei-Jun SHI State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China Engineering Center of Desertification and Blown-Sand Control of Ministry of Education Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Key Laboratory of Environmental Change and Natural Disaster of Ministry of Education Beijing Normal UniversityBeijing 100875China Centro de Investigaciones Sobre Desertificaci'on Consejo Superior de Investigaciones Cientı'ficas(CIDECSIC-UV-Generalitat alenciana)ClimateAtmosphere and Ocean Laboratory(Climatoc-Lab)Moncada 46113Spain Regional Climate Group Department of Earth SciencesUniversity of GothenburgGothenburg 40530Sweden CSIRO Environment CanberraACT 2600Australia Australian Research Council Centre of Excellence for Climate Extremes CanberraACT 2600Australia State Meteorological Agency Balearic Islands OfficePalma de Mallorca 07015Spain School of Atmospheric Sciences Sun Yat-sen UniversityZhuhai 519082China Interuniversity Department of Regional and Urban Studies and Planning(DIST) Politecnico and University of TurinTurin 10125Italy School of Earth and Environmental Sciences Seoul National UniversitySeoul 08826South Korea Atmospheric and Oceanic Sciences Program Princeton UniversityPrinceton NJ 08544USA Geophysical Fluid Dynamics Laboratory NOAAPrinceton NJ 08544USA

Near-surface wind speed exerts profound impacts on many environmental issues,while the long-term(≥60 years)trend and multidecadal variability in the wind speed and its underlying causes in global high-elevation and mountainous areas(e.g.,Tibetan Plateau)remain largely ***,by examining homogenized wind speed data from 104 meteorological stations over the Tibetan Plateau for 1961-2020 and ERA5 reanalysis datasets,we investigated the variability and long-term trend in the near-surface wind speed and revealed the role played by the westerly and Asian *** results show that the homogenized annual wind speed displays a decreasing trend(-0.091 m s^(−1)per decade,p<0.05),with the strongest in spring(-0.131 m s^(−1)per decade,p<0.05),and the weakest in autumn(-0.071 m s^(−1)per decade,p<0.05).There is a distinct multidecadal variability of wind speed,which manifested in an prominent increase in 1961-1970,a sustained decrease in 1970-2002,and a consistent increase in *** observed decadal variations are likely linked to large-scale atmospheric circulation,and the correlation analysis unveiled a more important role of westerly and East Asian winter monsoon in modulating near-surface wind changes over the Tibetan *** potential physical processes associated with westerly and Asian monsoon changes are in concordance with wind speed change,in terms of overall weakened horizontal air flow(i.e.,geostrophic wind speed),declined vertical thermal and dynamic momentum transfer(i.e.,atmospheric stratification thermal instability and vertical wind shear),and varied Tibetan Plateau *** indicates that to varying degrees these processes may have contributed to the changes in near-surface wind speed over the Tibetan *** study has implications for wind power production and soil wind erosion prevention in the Tibetan Plateau.

关键词： Tibetan Plateau Wind speed Decadal change Atmospheric circulation Physical processes

Asymmetrical response of summer rainfall in East Asia to CO_(2)forcing

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Science Bulletin 2022年第2期67卷 213-222,M0004页

作者： Se-Yong song Sang-wook Yeh Soon-Il An Jong-Seong Kug Seung-Ki Min seok-woo son Jongsoo Shin Department of Marine Sciences and Convergence Technology Hanyang UniversityAnsan 15588South Korea Department of Atmospheric Sciences/Irreversible Climate Change Research Center Yonsei UniversitySeoul 03722South Korea Division of Environmental Science and Engineering Pohang University of Science and TechnologyPohang 37673South Korea Institute for Convergence Research and Education in Advanced Technology Yonsei UniversityIncheon 21983South Korea School of Earth and Environmental Science Seoul National UniversitySeoul 08826South Korea

Understanding the regional hydrological response to varying CO_(2)concentration is critical for cost-benefit analysis of mitigation and adaptation polices in the near future. To characterize summer monsoon rainfall change in East Asia in a changing CO_(2)pathway, we used the Community Earth System Model(CESM) with28 ensemble members in which the CO_(2)concentration increases at a rate of 1% per year until its quadrupling peak, i.e., 1468 ppm(ramp-up period), followed by a decrease of 1% per year until the present-day climate conditions, i.e., 367 ppm(ramp-down period). Although the CO_(2)concentration change is symmetric in time, the amount of summer rainfall anomaly in East Asia is increased 42% during a rampdown period than that during a ramp-up period when the two periods of the same CO_(2)concentration are compared. This asymmetrical rainfall response is mainly due to an enhanced El Ni?o-like warming pattern as well as its associated increase in the sea surface temperature in the western North Pacific during a ramp-down period. These sea surface temperature patterns enhance the atmospheric teleconnections and the local meridional circulations around East Asia, resulting in more rainfall over East Asia during a ramp-down period. This result implies that the removal of CO_(2)does not guarantee the return of regional rainfall to the previous climate state with the same CO_(2)concentration.

关键词： CO_(2)concentration East Asian summer monsoon Asymmetric rainfall El Ni?o-like warming

Development of Preliminary Design Program for Combustor of Regenerative Cooled Liquid Rocket Engine

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Journal of Thermal Science 2011年第5期20卷 467-473页

作者： Won Kook Cho woo seok Seol Min son Min Kyo Seo Jaye Koo Korea Aerospace Research Institute DaejoenRepublic of Korea Graduate Student Korea Aerospace UniversityGoyangRepublic of Korea School of Aerospace and Mechanical Engineering Korea Aerospace UniversityGoyangRepublic of Korea

An integrated program was established to design a combustor for a liquid rocket engine and to analyze regenerative cooling results on a preliminary design *** of burnt gas from a kerosene-LOx mixture in the combustor and rocket performance were calculated from CEA which is the code for the calculation of chemical *** heat transfer of regenerative cooling was analyzed by using SUPERTRAPP code for coolant properties and by one-dimensional correlations of the heat transfer coefficient from the combustor liner to the *** of the combustors of F-1 and RS-27A engines were designed from similar input data and the present results were compared to actual data for ***,the combustors of 30 tonf class,75 tonf class and 150 tonf class were designed from the required thrust,combustion chamber,exit pressure and mixture ratio of *** wall temperature,heat flux and pressure drop were calculated for heat transfer analysis of regenerative cooling using the profiles.

关键词： Liquid rocket engine Preliminary design of Combustor Regenerative cooling

Dislocation characteristics and dynamic recrystallization in hot deformed AM30 and AZ31 alloys

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Journal of Magnesium and Alloys 2022年第12期10卷 3495-3505页

作者： Hyeon-woo son Soong-Keun Hyun Metallic Materials Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea Department of Materials Science and Engineering Inha UniversityIncheon 22212Republic of Korea

Zn addition to Mg alloys activates non-basal slip or twinning with solute softening *** the other hand,the effects of the Zn solute on the macroscopic dislocation behavior and dynamic recrystallization are not completely ***,it is unclear ifslip can be affected by changes in the c/a ratio of solute *** study was conducted to understand the solute strengthening of Zn addition and its effects on the dislocation characteristics and dynamic recrystallization.A hot torsion test was performed on both AM30 and AZ31 alloys up to a high strain to investigate the Zn solute effect on the dislocation characteristics and dynamic *** dislocation components of the hot torsioned alloys were evaluated by X-ray line profile analysis and electron backscatter *** results showed that the Zn solutes slightly accelerate strain accumulation at the initial stages of hot deformation,which accelerated recrystallization at high *** dislocation characteristics were changed dynamically by Zn addition:fortified-type slip,dislocation arrangement and strain anisotropy *** most important point was that the dislocation characteristics were changed dramatically at the critical strain for recrystallization and high strain *** addition of Zn also acted greatly in these strain *** indicates that the rapid formation of-type slip at the serrated grain boundaries occurs at the initiation of dynamic recrystallization and the increase in the grain triple junction because grain refinement has a great influence on the dislocation characteristics at high strain.

关键词： Magnesium alloy X-ray line profile Solid solution Dislocation density Dynamic recrystallization

Suggestion of advanced regression model on friction angle of fault gouge in South Korea

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第6期13卷 1368-1379页

作者： Seong-woo Moon Hyun-seok Yun Yong-seok Seo Department of Earth and Environmental Sciences Chungbuk National University1 Chungdae-roCheongju-siChungcheongbuk-do28644South Korea

Although friction characteristics of fault gouge are important to understand reactivation of fault,behavior of earthquake,and mechanism of slope failure,analysis results of fault gouge have low accuracy mostly than those of soils or rocks due to its high heterogeneity and low ***,to improve the accuracy of analysis results,we conducted simple regression analysis and structural equation model analysis and selected major influential factors of friction characteristics among many factors,and then we deduced advanced regression model with the highest coefficient of determination(R^(2)) via multiple regression *** most coefficients of determination in simple regression analysis are below0.3-0.4,coefficient of determination in multiple regression analysis is remarkably large as 0.657.

关键词： Fault gouge Friction angle Simple regression analysis Structural equation model analysis Multiple regression analysis

Conceptual Design for a Kerosene Fuel-rich Gas-generator of a Turbopump-fed Liquid Rocket Engine

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Journal of Thermal Science 2012年第5期21卷 428-434页

作者： Min son Jaye Koo Won Kook Cho Eun seok Lee Graduate Student Korea Aerospace UniversityGoyang Republic of Korea School of Aerospace and Mechanical Engineering Korea Aerospace UniversityGoyang Republic of Korea Korea Aerospace Research Institute Daejeon Republic of Korea

A design method for a kerosene fuel-rich gas-generator of a liquid rocket engine using turbopumps to supply propellant was performed at a conceptual level. The gas-generator creates hot gases, enabling the turbine to operate the turbopumps. A chemical non-equilibrium analysis and a droplet vaporization model were used for the estimation of the burnt gas properties and characteristic chamber length. A premixed counter-flow flame analysis was performed for the prediction of the burnt gas properties, namely the temperature, the specific heat ratio and heat capacity, and the chemical reaction time. To predict the vaporization time, the Spalding model, using a single droplet in convective condition, was used. The minimum residence time in the chamber and the characteristic length were calculated by adding the reaction time and the vaporization time. Using the characteristic length, the design methods for the fuel-rich gas-generator were established. Finally, a parametric study was achieved for the effects of the O/F ratio, mass flow rate, chamber pressure, initial droplet temperature, initial droplet diameter and initial droplet velocity.

关键词： Liquid rocket engine Conceptual design Fuel-rich gas-generator Sensitivity analysis

Estimation of genetic parameters on growth characteristics of a 35-year-old Pinus koraiensis progeny trial in South Korea

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Journal of Forestry Research 2021年第5期32卷 2227-2236页

作者： Kyungmi Lee In Sik Kim seok woo Lee Division of Forest Tree Improvement Department of Forest BioresourcesNational Institute of Forest ScienceSuwonRepublic of Korea

The effects of genetic and environmental factors on Pinus koraiensis growth were studied based on a35 year-old progeny trial composed of open-pollinated offspring of twenty-one plus ***,DBH and volume of the offspring was analyzed using restricted maximum likelihood/best linear unbiased prediction in mixed model *** site and family effects on the three traits were *** distinct growth of offspring by site with disparate climates corroborated the importance of planting species in suitable *** differences by family was significant,emphasizing the importance of identifying families with either superior or inferior *** parental ranking was assigned in the sites,inferring the breeding value of each plus *** estimates of individual heritability(h_(i)^(2))of height,DBH and volume growth were 0.169-0.645,0.108-0.331 and 0.129-0.343 respectively,with higher h_(i)^(2) of the height than DBH on each *** of variance of genetic effect was higher with DBH in some cases,indicating the scope for selection is larger for this trait despite the lower heritability compared to *** the variation between families in terms of the performance stability across sites,consideration of the genotype by environment interaction is required in selecting materials to be used in reforestation with Korean pine.A few families with either superior or inferior performance retained their parental ranking for at least a *** families with increased growth on a particular site were identified,indicating their high breeding value and low *** in the genetic performance of the families by site requires delineation of the breeding region of the species.

关键词： Pinus koraiensis Genetic parameters Genotype by environment interaction Tree improvement Progeny trial

The effect of fertilization on early growth of konara oak and Japanese zelkova seedlings planted in a harvested pitch pine plantation

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Journal of Forestry Research 2016年第4期27卷 863-870页

作者： A-Ram Yang Jaehong Hwang Min seok Cho Yowhan son Forest Practice Research Center National Institute of Forest Science Department of Environmental Science and Ecological Engineering Graduate School Korea University

We determined a suitable amount of fertilizer for konara oak（Quercus serrata） and Japanese zelkova（Zelkova serrata） planted in a harvested pitch pine（Pinus rigida） plantation. Two-year-old bare-root seedlings of konara oak and one-year-old containerized seedlings of Japanese zelkova were planted in April 2011. Three plots were established for each tree species to evaluate each of three fertilization applications. Solid compound fertilizer（N：P：K = 3：4：1） was applied yearly in three amounts（control： no fertilization, F1： 180 kg ha-1, and F2：360 kg ha-1）, every May from 2011 to 2013. We measured the root collar diameter and height, and analyzed the compartmental N and P concentrations. Compartmental N concentrations of konara oak and Japanese zelkova were not consistent based on amount of fertilization. However,the compartmental P concentrations of konara oak and Japanese zelkova were significantly different in the order of F2, F1, and control. Although the differences in growth of konara oak appeared after 3 years of fertilization,Japanese zelkova showed differences after only 2 years of fertilization owing to differences in seedling type. Growth of konara oak was affected by fertilization at F1 and F2 in2013. However, growth of Japanese zelkova was affected only at F2. Nutrient demand of Japanese zelkova appeard to be higher than that of konara oak, at least during the early growing period. Results from this study could be practically used in harvested pitch pine plantations to determine appropriate fertilization regimes.

关键词： fertilization Japanese plantation fertilizer pitch planted seedling practically collar yearly

Novel acoustic features for speech emotion recognition

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Science China(Technological Sciences) 2009年第7期52卷 1838-1848页

作者： ROH Yong-Wan KIM Dong-Ju LEE woo-seok HONG Kwang-seok School of Information and Communication Engineering Sungkyunkwan University300Chunchun-dongJangan-guSuwonKyungki-do440-746Korea Development Division / DSP Development Team Tamul Multimedia10th Fl.Anyang Trade Center1107Bisan-DongDongAn-GuAnyang-City431-050Korea

This paper focuses on acoustic features that effectively improve the recognition of emotion in human *** novel features in this paper are based on spectral-based entropy parameters such as fast Fourier transform(FFT) spectral entropy,delta FFT spectral entropy,Mel-frequency filter bank(MFB) spectral entropy,and Delta MFB spectral ***-based entropy features are *** reflect frequency characteristic and changing characteristic in frequency of *** implement an emotion rejection module using the probability distribution of recognized-scores and *** reduces the false recognition rate to improve overall ***-scores and rejected-scores refer to probabilities of recognized and rejected emotion recognition results,*** scores are first obtained from a pattern recognition *** pattern recognition phase uses the Gaussian mixture model(GMM).We classify the four emotional states as anger,sadness,happiness and *** proposed method is evaluated using 45 sentences in each emotion for 30 subjects,15 males and 15 *** results show that the proposed method is superior to the existing emotion recognition methods based on GMM using energy,Zero Crossing Rate(ZCR),linear prediction coefficient(LPC),and pitch *** demonstrate the effectiveness of the proposed *** of the proposed features,combined MFB and delta MFB spectral entropy improves performance approximately 10% compared to the existing feature parameters for speech emotion recognition *** demonstrate a 4% performance improvement in the applied emotion rejection with low confidence score.

关键词： speech emotion recognition MFB spectral entropy entropy emotion recognition rejection