Silica, Alumnia, Clay를 첨가한 지르콘의 소결특성에 미치는 영향

이근봉,정승화,이주성,홍경표,조범래,문종수,강종봉,Lee, Keun-Bong,Jung, Seung-Hwa,Lee, Ju-Sung,Hong, Gyung-Pyo,Jo, Bum-Rae,Moon, Jong-Su,Kang, Jong-Bong 한국재료학회 2008 한국재료학회지 Vol.18 No.7

Effect The effect of sintering additives ($SiO_2$, $Al_2O_3$, Clay) on the mechanical characteristics of sintered zircon was investigated. 1 vol% of additives in zircon powder was was sintered at $120{\sim}1500^{\circ}C$, the mechanical characteristics were measured, and microstructure analysis were was conducted. $Al_2O_3$ and clay additions increase the formation of monoclinic and tetragonal-$ZrO_2$ formation. An addition of SiO2 addition suppressed the formation of tetragonal-$ZrO_2$ formation., The A specimen sintered at $1400^{\circ}C$ showed the a density of $4.05\;g/cm^3$ and the a microhardness of 1120 HV, respectively.

Silica가 첨가된 지르콘 소결거동

이근봉,강종봉,Lee, Keun-Bong,Kang, Jong-Bong 한국재료학회 2008 한국재료학회지 Vol.18 No.11

The sintering behavior of zircon with silica was investigated. Zircon with 5 vol% of sedimentation $SiO_2$ resulted in the apparent density of $4.45\;g/cm^3$, the diametral tensile strength of $12.125\;kgf/cm^2$, and the micro Vickers hardness of 1283 HV. The dissociation temperature and mechanical characteristics of the $ZrSiO_4$ were changed with different kinds of $SiO_2$. $SiO_2$ addition prevented dissociation of $ZrSiO_4$. Zircon with 5 vol% of sedimentation $SiO_2$ and with 5 vol% of fused $SiO_2$ resulted in increased diametral tensile strength and increased micro Vickers hardness by suppression of $ZrSiO_4$ dissociation and low temperature liquid $SiO_2$ formation. Zircon with fumed $SiO_2$ and quartz $SiO_2$ resulted in decreased diametral tensile strength and decreased micro Vickers hardness because of cristobalite and quartz phase formation and high temperature liquid $SiO_2$ formation. Zircon with 10 vol% of $SiO_2$ resulted in decreased diametral tensile strength and decreased micro Vickers hardness because of weak particle coupling due to excess formation of liquid $SiO_2$.

탐색자의 주제배경이 탐색효과에 미치는 영향

이근봉 한국비블리아학회 1994 한국비블리아학회지 Vol.7 No.-

The Purpose of this study is to verify the effect of the searcher's subject background on the result of online database searches. To achieve this purpose, an experimental method was adopted. 180 students performed online searches in the three different libraries chosen for this study. The subjects were classified into two groups according to the scores of the test. Data concerning processes, behavior, and results of the searches performed by the subjects in real situations were gathered. Immediately following the searches, the extent of their subject background were assessed through interview. The search effect consists of the 4 elements: search efficiency (the number of terms used per unit time), the number of relevant documents, the number of relevant documents per unit time, precision ratio. The major findings of this study are summarized as belows. 1. The searchers with strong subject background has significantly higher efficiency in searches made. Group A (of those with strong subject back-ground) use more search terms per unit time than Group B (of those with weak subject background) do. 2. In the searches made by those with strong subject background, more relevant documents art retrieved. 3. In the searches made by those with strong subject background, more relevant documents per unit time are retrieved. 4. The searchers with strong subject background has significantly higher precision ratio in searches made. In the searches made by those with strong subject background, more relevant documents of documents retrieved are retrieved.

Y₂O₃ 및 La₂O₃ 첨가가 알루미나의 소결거동에 미치는 영향

이근봉,강종봉,Lee, Keun Bong,Kang, Jong Bong 한국재료학회 2016 한국재료학회지 Vol.26 No.2

In this study, to increase the strength and enhance the sintering property of $Al_2O_3$, $Y_2O_3$ and $La_2O_3$ were added; the effects of these additions on the sintering characteristics of $Al_2O_3$ were observed. Adding 1% of $Y_2O_3$ to $Al_2O_3$ repressed the development of abnormal particles and reduced the grain boundary migration of $Al_2O_3$, curbing pores to capture particles; as such, the material showed a fine microstructure. But, when over 2% of $Y_2O_3$ was added, the sintering property was reduced because of abnormal particle grain growth and pore formation in particles. Adding 1% of $Y_2O_3$ and $La_2O_3$ to $Al_2O_3$ led to the development of abnormal particles and formed pores in the particles; when over 3% of $La_2O_3$ was added, the sintering property was reduced because the shape of the $Al_2O_3$ particles changed to angled plates.

공기 보조 분사 장치를 이용한 엔진 성능 향상 및 연비 개선

김세웅,심국상,이근봉 金烏工科大學校 1995 論文集 Vol.16 No.-

This paper describes the improvement of engine performence and fuel consumption through improved combustion formed by the tumble and swirl flows of an in-cylinder fuel-air mixture that uses an air forced fuel injector(AFI) which used compressed air. The AFI is designed to promote fuel atomization and to form uniform fuel-air mixture. In order to make up the tumble and the swirl flows of the in-cylinder mixture, the end of AFI is attached to the tube containing the fuel-air mixture to ensure the adequate flow and to ensure that the remaining kinds of mixture will flow effectively. In order to investigate the improvement of engine performence and fuel consumption, 2 models of tubes which make tumble and swirl flows were utilized. Each model was examined according to engine speed, intake manifold pressure and excess air ratio and compared with a base engine. Compared with the base engine, the results show that the AFI improves the engine performance and the brake specific fuel consumption(BSFC) in all of the engine speeds and the boost pressures at the tumble and the swirlflows. It also decreases exhaust emission of hydrocarbon(HC)

소결조제의 첨가가 지르콘 소결체의 물리적 특성에 미치는 영향

이근봉 ( Keun Bong Lee ),정승화 ( Seung Hwa Jung ),이주성 ( Ju Sung Lee ),문종수 ( Jong Su Moon ),강종봉 ( Jong Bong Kang ) 경남대학교 신소재연구소 2007 신소재연구 Vol.19 No.-

EN50289 동축케이블 전달 임피던스 측정 방법을 이용한 통신 케이블의 차폐 효과 분석

이근봉(Keunbong Lee),장난(Nan Zhang),전지운(Jiwoon Jeon),송승제(Seungje Song),나완수(Wansoo Nah) 한국전자파학회 2014 한국전자파학회논문지 Vol.25 No.11

본 논문에서는 EN50289 규격에 따른 동축케이블의 전달 임피던스 측정을 이용하여 여러 가지 통신 케이블의 차폐 특성을 분석하였다. EN50289 규격에서의 전달 임피던스 측정 방법은 CENELEC(European Committee For Electrotechnical Standardization)에서 규정한 Triaxial 방법이며, IEC Standard 96-1에서 규정한 Triaxial 방법과 달리 측정하고자 하는 동축케이블과 외부 도체의 직경에 관계없이 동축케이블의 전달 임피던스를 측정할 수 있는 장점이 있다. 본 논문에서는 EN50289 규격에 따른 동축케이블의 전달 임피던스 측정장치를 설계/제작하였으며, 이것을 이용한 실험 결과를 통해 측정 시스템의 신뢰할만한 주파수 대역을 결정하였고, 동축케이블의 쉴딩 기법의 차이에서 오는 영향에 대하여 분석하였다. 전달 임피던스 측정 결과, 케이블의 쉴딩 기법에 따라 전달 임피던스의 상당한 차이가 있음을 보였다. 또한, RG-58 통신용 케이블의 전달 임피던스 이론식에 의한 계산값과 측정값의 비교를 통하여 측정된 데이터가 유효함을 보였다. In this work by measuring transfer impedance of communication cables using EN50289 its Shielding effect is analyzed. transfer impedance measurement triaxial method using EN50289 is defined in CENELEC, it is unlike triaxial method prescribed in IEC Standard 96-1, can be measured regardless of diameter of coaxial cable and outer conductor. in this paper, transfer impedance measurement device of coaxial cable is designed and made according to EN50289 standard, The analysis determines the reliable working frequency range of coaxial cable and examined the impact of different shielding methods on coaxial cable. The transfer impedance measurements show considerable variations in results with various shielding methods. also the measurement procedure is verified through comparison of calculated and measured transfer impedance of RG-58 cable.

DFSS를 이용한 Diesel Engine의 Idle Combustion Noise 개선

이근봉(Keunbong Lee),장현모(Hyunmo Jang),이상수(Sangsu Lee),이문식(Moonsig Lee) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5

Current diesel engines have common rail FIE system, VGT, EGR and swirl to meet stringent emission regulation and comply with customer’s demand like fuel economy and driving pleasure. To optimize these control factors by conventional EMS calibration methods, calibration engineers need a lot of calibration time and efforts. Therefore instead of conventional methods, general DFSS method that has been successfully used on various engineering quality problems was applied in this study. This study is to improve the combustion noise without fuel economy and emissions penalties in idle conditions. After finding the effects of control factors on combustion noise, emissions and fuel economy using DFSS process, the investigated and the optimized control factors were confirmed at 4 kinds of idle operation conditions. The objective of this study was achieved with optimum control factors.

각속도 변동 지수와 크랭크각 지수를 이용한 가솔린 기관의 실화 검출

이근봉,김세웅,심국상 國立金烏工科大學校附設生産技術硏究所 1997 産業技術開發硏究 Vol.13 No.-

This paper introduces a diagnostic technique for the detection of faulty cylinders of internal combustion engines, using the indexes of the angular velocity variation and the crankshaft angle. Many types of faults may occur during the operation of internal combustion engines. These include low compression pressure, failure of ignition or combustion of malfunction of the fuel system. Early detection and correction of engine faults restore proper performance, improve engine efficiency and reduce costs. From the idea that the fluctuation of crankshaft speed contains the information of combustion phenomena, angular velocity variation is measured, with an interval timer and a magneric pick-up sensor, by timing the flywheel gear teeth as they pass the sensor. The angular velocity and angular acceleration are determined by cylinder pressure, load, inertia, and friction of the engine. The angular acceleration patterns, as well as the velocity patterns, are varied according to the relative effects between cylinder pressure and reciprocating inertia. Therefore the patterns are classified into three regions; the inertia dominant region, the combined region, the pressure dominant region. In this paper, misfire detection was investigated according to the regions with parameters defined for misfire detection. By this method, the single misfire or multiple misfires can be detected

Silica가 첨가된 지르콘 소결거동

이근봉 ( Keun Bong Lee ),강종봉 ( Jong Bong Kang ) 경남대학교 신소재연구소 2008 신소재연구 Vol.20 No.-