http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
정영관(Young-guan Jung),김경훈(Kyoung-hoon Kim),김세웅(Se-woong Kim) 한국자동차공학회 2002 한국자동차공학회 지부 학술대회 논문집 Vol.- No.-
Numerical analysis on the atomic and molecular level is necessary as properties of materials are based on the correlation between atoms or molecules. The embedded atom method established on density functional theory was developed as a new means for calculating various properties and phenomena of realistic metal systems. In this study, we had corrected constitutive formulae and parameters, and developed the program on the nickel and the palladium for the purpose of doing Embedded Atom Method analyses on metals. And then we have computed the properties of the nickel and the palladium on the fundamental scale of the atomic structure. As a result, simulated ground state properties, such as the lattice constant, elastics constants and sublimation energy, show good agreement with Daw's simulation data and with experimental data.
정영관(Young Guan Jung),김경훈(Kyoung Hoon Kim),이근진(Keun Jin Lee) 한국수소및신에너지학회 2001 한국수소 및 신에너지학회논문집 Vol.12 No.2
In order to study the relation between expansion of the specimen and the hydrogen absorption rate, thin palladium plates with cold rolling were used. Thin palladium plates were hydrogenated in the 0.1mol H₂SO₄ electrolyte by electrochemical method. The expansion behavior on hydrogen absorbing can be obtained by X-ray diffraction analysis and by micrometer measurement. It is noted that the expansion rate of Palladium specimens in thickness direction is larger than in length and width direction. The lattice constants increase quickly with increasing hydrogen absorbing rate up to 0.5, but above the rate they keep constant. Also the clues for plastic deformation, such as slip lines and voids, were observed in abundantly even though the plates were hydrogenated once.
디젤기관에 대한 앳킨슨사이클 구성과 사이클의 열역학적 해석에 관한 연구
김철수,정영관,장태익,Kim Chul Soo,Jung Young Guan,Jang Tae lk 한국마린엔지니어링학회 2005 한국마린엔지니어링학회지 Vol.29 No.2
The present study composed a diesel-atkinson cycle of high expansion as a method of achieving high efficiency in diesel cycle engines. It also interpreted the cycle engine thermodynamically analysis to determine the possibility of the improvement of thermal efficiency and clarified the characteristics of several factors . According to the result of theoretical analysis, heat efficiency was highest when expansion-compression ratio Reど:1. In addition. diesel engines with high apparent compression ratio had higher expansion-compression ratio than otto engines and consequently their effect of high expansion was high. which in turn enhanced thermal efficiency. When the atkinson cycle was implemented in a real diesel engine by applying the miller cycle through the variation of the closing time of the intake valve, the effective compression ratio and the quantify of intake air decreased and as a result, the effect of high expansion was not observed. Accordingly. the atkinson cycle can be implemented when the quantity of intake air is compensated by supercharge and the effective compression ratio is maintained at its initial level through the reduction of the clearance volume. In this case. heat efficiency increased by $4.1\%$ at the same expansion-compression ratio when the apparent compression ratio was 20 and the fuel cut off ratio was 2. As explained above, when the atkinson cycle was used for diesel cycle. heat efficiency was improved. In order to realize high expansion through retarding the intake value closing time, the engine needs to be equipped with variable valve timing equipment, variable compression ratio equipment and supercharged Pressure equipment. Then a diesel-atkinson cycle engine is realized.
김경훈(Kyoung Hoon Kim),정영관(Young Guan Jung),한철호(Chul Ho Han) 한국추진공학회 2009 한국추진공학회지 Vol.13 No.4
An exergy analysis is carried out for the regenerative steam-injection gas turbine systems which has a potential of enhanced thermal efficiency and specific power. Using the analysis model in the view of the second law of thermodynamics, the effects of pressure ratio, steam injection ratio, ambient temperature and turbine inlet temperature are investigated on the performance of the system such as exergetic efficiency, heat recovery ratio of heat exchangers, exergy destruction, loss ratios, and on the optimal conditions for maximum exergy efficiency. The results of computation show that the regenerative steam-injection gas turbine system can make a notable enhancement of exergy efficiency and reduce irreversibilities of the system.
신재생에너지로 구동되는 칼리나 사이클 기반 삼중 병합 생산 시스템의 열역학적 성능 특성
한철호(CHUL HO HAN),김경훈(KYOUNG HOON KIM),정영관(YOUNG GUAN JUNG) 한국수소및신에너지학회 2021 한국수소 및 신에너지학회논문집 Vol.32 No.6
The recently proposed Kalina based power and cooling cogeneration cycles (KPCCCs) have shown improvement in the energy utilization of the system compared to the basic Kalina cycle. This paper suggests a combined tri-cogeneration system for power, heating and cooling based on the Kalina cycle. And thermodynamic performances of the suggested system based on the first and second thermodynamic laws are parametrically investigated with respect to the ammonia mass fraction and the boiler pressure. Results showed that the thermodynamic performance of the system could be greatly improved compared to the former KPCCCs.
개량 9Cr-1Mo 강의 장시간 크리프거동에 미치는 경도와 하부조직의 영향
박규섭(Kyu-Seop Park),이근진(Kun-Jin Lee),정한식(Han-Shik Chung),김정호(Jung-Ho Kim),정영관(Young-Guan Jung),엔도타카오(Takao Endo) Korean Society for Precision Engineering 2004 한국정밀공학회지 Vol.21 No.2
Interrupted creep tests were carried out on the Mod.9Cr-1Mo steel in order to investigate the structural degradation during creep. The ranges of creep stress and temperature were from 71 to 167MPa and 873 to 923K, respectively. The change of hardness and tempered martensitic lath width were measured in the grip and gauge parts of interrupted specimens. The lath structure was thermally stable in static conditions, but was not stable during creep, and the structural evolution was enhanced by creep strain. The relation between the change in lath width and strain was described in the from, △W=a(W<SUB>s</SUB>-W<SUB>o</SUB>)ㆍε, where ε is the strain, W<SUB>o</SUB> is the initial lath width, W<SUB>s</SUB> is the final lath width depending solely on stress, and a is the constant of the magnitude of 0.67 ㎛ /strain. The change in Vickers hardness was expressed by a one-valued function of creep life consumption ratio. Based on the empirical relation between strain and lath width, a model was proposed to explain the relation between change in hardness and creep life consumption ratio. The model revealed that about 65% of dislocations in lath structures were eliminated by the migration of subboundaries.
Ti-Al 금속간화합물의 고온변형거동 및 라멜라조직의 결정방위 분포
박규섭(Kyu-Seop Park),강창용(Chang-Yong Kang),이근진(Keun-Jin Lee),정한식(Han-Shik Chung),정영관(Young-Guan Jung),福富洋志(Hiroshi Fukutomi) Korean Society for Precision Engineering 2004 한국정밀공학회지 Vol.21 No.10
High temperature uniaxial compression tests in the alpha single phase region were carried out on the Ti-43mol%AI intermetallic compound, in order to obtain oriented lamellar microstructure. The compression deformation temperatures and strain rates are from 1573K to 1623K and 1.010?⁴/s to 5.0×10?³/s, respectively. Fully lamellar microstructure was observed after the uniaxial compression deformation in a single phase region followed by cooling to room temperature. Lamellar colony diameter depended on strain rates and test temperatures. The diameter varied between 860㎛ and 300㎛ . Stress-strain curve showed a work softening and the size of lamellar colony diameter varied depending on peak stresses. This shows the occurrence of dynamic recrystallization. Texture measurements after the uniaxial compression deformation, showed the development of fiber during dynamic recrystallization. It is seen that the area for the maximum pole density existed in 35 degrees away from the compression plane. The texture sharpens with a decrease in strain rate.