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몽골인 학습자의 한국어 단모음에 관한 실험음성학적 연구
안성민 ( An Sung-min ),하영우 ( Ha Young-woo ) 서강대학교 언어정보연구소 2023 언어와 정보 사회 Vol.49 No.-
Based on an experimental phonetic methodology, this study examines Mongolian learners’ spatial structural aspects and characteristics in pronouncing Korean monophthongs. To this end, a monophthong experiment was conducted on Mongolian learners, and the spatial structural characteristics between individual vowels were compared and analyzed with proficiency levels as the main variable. As a result of the study, all learners distinguished the pronunciation of /ㅣ/ and /E/ and intermediate and advanced learners tended to even better distinguish between the two vowels by adjusting /ㅣ/ and /E/ articulation spaces, respectively. The spatial structure of the back vowel /ㅡ/ showed the most noticeable variation depending on proficiency levels. Beginner learners showed a wide distribution in which the space of /ㅡ/ overlaps some of the front and back vowel spaces, and F1 was relatively lower compared to that of Korean speakers. As learning progressed, F1 was adjusted more closely to that of Korean speakers becoming more frequent, but F2 differed from that of Korean speakers, even for advanced learners. In the back rounded vowels /ㅗ/ and /ㅜ/, all learner groups showed significant differences in F1, but beginner learners pronounced the F2 of /ㅜ/ lower than that of /ㅗ/ unlike general Korean pronunciation. However, as the proficiency level increase, the F2 of /ㅜ/ increased to that of general Korean pronunciation.
이상훈(Sang-Hoon Lee),윤태일(Tae-Il Yoon),안근묵(Kun-Muk An),하경호(Kyoung-Ho Ha) 대한설비공학회 2010 대한설비공학회 학술발표대회논문집 Vol.2010 No.6
Knowledge of ground thermal properties is most important for the proper design of large scale BHE(borehole heat exchanger) systems. The type, pipe size and thermal performance of the BHE is highly dependent on the ground source heatpump system-efficiency and instruction cost. Thermal response tests with mobile measurement devices were developed primarily for in-situ determination of design data for large diameter BHE. The main purpose has been to determine in-situ values of effective ground thermal conductivity and thermal resistance, including the effect of ground-water flow and natural convection in the boreholes. The test rig is set up on a some trailer, and contains a circulation pump, a inline heater, temperature sensors, flow meter, power analysis meter and a data logger for recording the temperature, fluid flow data. A constant heat power is injected into the borehole through the U-pipes system of test rig and the resulting temperature change in the borehole is recorded. The recorded temperature data are analysed with a line-source model, which gives the effective insitu values of rock thermal conductivity and borehole thermal resistance of large diameter BHE.
A Study of a Combined Microwave and Thermal Desorption Process for Contaminated Soil
Sang An Ha,Kyoung Sik Choi 대한환경공학회 2010 Environmental Engineering Research Vol.15 No.4
In order to treat soil contaminated with high percentages of water and petroleum, the combined microwave and thermal desorption process was studied, which was composed of the consecutive connection of two pre-treatment processes. For the thickness of the contaminated soil layer on the transfer conveyor belt, the optimal total petroleum hydrocarbon (TPH) removal rate was studied with respect to the duration of microwave exposure in the consecutive process combined with thermal desorption. The TPH removal rate when the contaminated soil layer thickness was 1 cm at 6 kW of microwave power was 80%. The removals rates for 2 and 3 cm soil layer thicknesses were both 70%. Under identical experimental conditions, the TPH removal rate for the microwave pre-treatment, when considering the soil particle size, was over 70%. The lowest TPH removal rate was achieved with a particle diameter of 2.35 mm. For contaminated soil with 30% water content, 6 kW and a thermal desorption temperature of 600℃ were the optimal operational conditions for the removal of THP. However, considering the fuel consumption cost, 4 kW and a thermal desorption temperature of 300℃ would be the most economic conditions.
Lee, An-Sung,Ha, Jin-Woong The Korean Society of Mechanical Engineers 2003 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.17 No.1
An eigenvalue design sensitivity formulation of a general nonsymmetric-matrix rotor-bearing system is devised. using the DDM (direct differential method). Then, investigations on the design sensitivities of critical speeds are carried out for an APU turbogenerator with a spline shaft connection. Results show that the dependence of the rate of change of the critical speed on the stiffness changes of bearing models of spline shaft connection points is negligible, and thereby their modeling uncertainty does not present any problem. And the passing critical speeds up to the 4th critical speed are not sensitive to the design stiffness coefficients of four main bearings. Further, the dependence of the rate of change of the critical speed on the shaft-element length changes shows quantitatively that the spline shaft has some limited influence on the 4th critical speed but no influence on the 1st to 3rd critical speeds. With no adverse effect from the spline shaft, the APU system achieves a critical speed separation margin of more than 40% at a rated speed of 60,000 rpm.
Effect of microwave irradiation on lipase-catalyzed reactions in ionic liquids
An, Gwangmin,Kim, Young Min,Koo, Yoon-Mo,Ha, Sung Ho The Korean Society of Analytical Science 2017 분석과학 Vol.30 No.3
Microwave-assisted organic synthesis has gained a remarkable interest over the past years because of its advantages - (i) rapid energy transfer and superheating, (ii) higher yield and rapid reaction, (iii) cleaner reactions. Ionic liquids are well known for their unique properties such as negligible vapor pressure and high thermal stability. With these properties, ionic liquids have gained increasing attention as green, multi-use reaction media. Recently, ionic liquids have been applied as reaction media for biocatalysis. Lipase-catalyzed reactions in ionic liquids provide high activity and yield compared to conventional organic solvents or solvent free system. Since polar molecules are generally good absorbent to microwave radiation, ionic liquids were investigated as reaction media to improve activity and productivity. In this study, therefore, the effect of microwave irradiation in ionic liquids was investigated on lipase catalyzed reactions such as benzyl acetate synthesis and caffeic acid phenethyl ester synthesis. Comparing to conventional heating, microwave heating showed almost the same final conversion but increased initial reaction rate (3.03 mM/min) compared to 2.11 mM/min in conventional heating at $50^{\circ}C$.
Ha, Sang An,Jung, Byong Ho,Lee, Jong Moon,Kim, Kwon Hoo,Wang, Jei Pil Trans Tech Publications, Ltd. 2013 Advanced materials research Vol.813 No.-
<P>The objective of this study was to increase flux and decomposition speed through the development of a multi-type electrical field decomposition facility that employs a more complex modulated electromagnetic field than that used in existing decomposition facilities where recalcitrant organics or heavy metals are combined together. Further, in this study, optimized foundational data was derived from the results obtained following field work. As a result, when an electrical field was applied to an electrolyzer, decomposition of the electrolyzer was carried out quickly, thereby showing higher efficiency because an electrical field was permeated to the contaminant faster compared to the case where an electrolyzer was not added. Keywords: Electromagnetic field, Heavy metal, Electrolyzer, Electrical field</P>
An Sung Lee,Jin Woong Ha 대한기계학회 2003 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.17 No.1
An eigenvalue design sensitivity formulation of a general nonsymmetric-matrix rotor-bearing system is devised, using the DDM (direct differential method). Then, investigations on the design sensitivities of critical speeds are carried out for an APU turbogenerator with a spline shaft connection. Results show that the dependence of the rate of change of the critical speed on the stiffness changes of bearing models of spline shaft connection points is negligible, and thereby their modeling uncertainty does not present any problem. And the passing critical speeds up to the 4th critical speed are not sensitive to the design stiffness coefficients of four main bearings. Further, the dependence of the rate of change of the critical speed on the shaft-element length changes shows quantitatively that the spline shaft has some limited influence on the 4th critical speed but no influence on the 1st to 3rd critical speeds. With no adverse effect from the spline shaft, the APU system achieves a critical speed separation margin of more than 40% at a rated speed of 60,000 rpm.<br/>
Ha, Tae-Woong,Lee, An-Sung The Korean Society of Mechanical Engineers 2000 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.14 No.3
In this paper the leakage prediction and rotordynamic analysis of an annular seal with a smooth rotor and circumferentially grooved stator are performed based on a three-controlvolume theory. The present analysis is validated by comparing with the experimental data of Iwatsubo and Sheng and theoretical results suggested by Marquette and Childs. For the leakage prediction the present analysis shows a good agreement with Marquette and Childs' result and a qualitation agreement with Iwatsubo and Shengs' experimental data. Direct and cross-coupled stiffness coefficients show closer agreement with the experimental values than those of Marquette and Childs. However, direct damping coefficient shows greater discrepancy from the experimental value than Marquette and Childs'.