• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2000년도 특별강연 및 춘계학술발표대회 개요집
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• pp.211-214
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• 2000

• 한국음향학회:학술대회논문집
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• 한국음향학회 2000년도 학술발표대회 논문집 제19권 2호
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• pp.161-164
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• 2000

음향공간의 질은 그 공간을 사용하는 사용자의 주관적인 판단에 의해 최종적으로 평가된다. 그러나 이와 같은 주관적인 판단은 주어진 공간에 대한 사용자의 종합적인 지각과 경험을 토대로 하여 이루어지는 것이므로 이를 정량 화하여 상호 비교하는 작업의 어려움과 한계는 많은 연구논문을 통해 지적된 바 있다 본 연구는 음향공간 내에서 음색지각의 변화를 JND개념을 이용하여 정량화하고 이를 음향선호도와 비교함으로써 기존의 주관적 평가방법보다 객관화된 평가방법 제안의 가능성을 논하고자 한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.1034-1039
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• 2001

Recently. development of a subway as a public transport has been increased rapidly. Therefore, large noise, which induced from vehicle itself as well as frictions between rails and train, may inflict a considerable damage to the adjacent structure and cause discomfort to neighboring residents. Nevertheless, adequate design guidelines to reduce outdoor noise are not yet established. The present work carried out a survey on the influence of outdoor subway noise using questionnaires. Also or noise measurements levels in those are as were performed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.151-156
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• 2000

The sound insulation performance of walls and floors for air-borne and structure-borne sounds in an apartment building is an important environmental factor which should be contemplated at the intial design stage for their thorough control. Recent increasing residents' demands for quality living spaces strongly urge the development of more accurate and efficient measurement and evaluation methods for the control of air-borne and structure-borne sound insulation. However, steel-structured apartment buildings, recently emerged as new building structures in the market, have not been thoroughly examined. The present work carried out an extensive survey for steel-structured apartment buildings, in an attempt to provide useful design data, and their sound insulation performances were compared with those of R.C. apartment buildings.

• KIEAE Journal
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• 제7권3호
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• pp.63-70
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• 2007

It is known that early reflections, their energy and delay times after the arrival of direct sound are important factors for speech intelligibility. In this basis, acoustical parameters like D50 and C80 had been proposed and are widely used for assessing the listening condition of rooms. These parameters are focused on the fraction of the early energy to the total, regardless of the spatial characteristics of the early reflections. This means that all the early reflections, arrived in certain time boundary. from front, behind, down and upside have the same impact on speech intelligibility. From the questionable simplicity, the influence of the direction of early reflections on speech intelligibility is examined in this study. A computer simulation speech intelligibility test, conducted for 22 university students, found that the reflection of vertical direction with method of the Paired comparison also the preference of 0.746 degree was visible an increase.

• KIEAE Journal
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• 제2권1호
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• pp.55-61
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• 2002

It seems inevitable for residential buildings to be high-rise and allocated near traffic roads due to the overcrowding in urban area. Acoustic environment in those residential buildings has been seriously deteriorated by the increase of traffic vehicles. Commonly used sound barriers have a limitation in controlling noise diffracted over the boundary of a sound barrier and hence are not effective to attenuate noise especially for the residential units in high level. The use of an enclosed noise barrier can be an alternative to supplement the defects of conventional noise barriers. The present work aims at providing useful data in designing enclosed noise barriers for residential areas adjacent to roads. Number of field measurements for various noise barriers and enclosed noise barriers were carried out and the results were discussed with relation to the proper design of enclosed noise barriers.

• 한국음향학회지
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• 제19권1호
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• pp.73-77
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• 2000

소음으로 인해 사용자가 느끼게 되는 어노이언스를 정량화하여 표현하고 평가하는 작업은 경제적이고 효율적이며 사용자 중심의 소음조절대책의 수립을 위하여 필수적이다. 바닥충격음의 경우, 정상소음과는 그 동적특성이 달라서 이와 같은 정량화 작업에 있어서 세심한 주의를 요한다. 본 연구에서는, 바닥충격음으로 인해 야기되는 어노이언스의 정량화를 위하여 일련의 청감실험이 시행되었다. 실험결과, 바닥구조체의 특성보다는 충격원의 특성이 사용자가 느끼는 라우드니스와 시끄러움에 보다 큰 영향을 미치는 것으로 나타났으며, 중량충격음이 경량충격음보다 5-6dB 정도 더 크고 시끄럽게 느끼는 것으로 분석되었다.

• 한국광물학회:학술대회논문집
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• 한국광물학회.대한자원환경지질학회.대한광업진흥공사 2002년도 추계 공동 심포지엄 논문집: 국내 자원의 현황과 전망
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• pp.137-151
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• 2002

최근 급속한 첨단산업의 발전과 더불어 각 분야에서 신소재 개발 등의 연구가 활발히 진행되고 있어 비금속 자원은 그 수요가 점차 증가하는 추세에 있다. 여러 비금속 자원 중 장석은 세라믹, 법랑, 타일, 유약용 등의 요업원료와 유리, 용접봉, 플라스틱, 페인트, 카리비료등 무기 재료 공업원료로 다양하게 사용되고 있는 비금속자원 이다. 2001년도 우리나라 장석 생산량은 389,361톤 (2001년도 광산물 수급현황, 2002, 5, 산업자원부)이며 매장량은 41,470,000톤 (2001년도 광산물 수급현황, 2002, 5, 산업자원부)이며 전국적으로 등록된 장석 광구수는 811개에 개발광산은 69개 이른다. 이상의 예를 보면 막대한 양의 매장량과 장석 광산이 알려져 있지만 실제 연중 가행 광산은 10개 광산 미만이며 영세한 상태로 체계적인 개발이 이루어지지 못하고 있다. 이런 문제점을 해소하고 장석 자원의 확보 및 안정적 공급을 위하여 장석의 정의, 용도, 품질요건, 부존, 산출상태, 가행광산현황 및 장석자원현황등을 규명하여 장석광산의 향후. 개발대책 및 고부가가치화에 필요한 자료를 제공하고자 한다.

• Journal of Welding and Joining
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• 제19권1호
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• pp.82-87
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• 2001

The creep-rupture and low cycle fatigue properties of transient liquid phase bonded joints of Ni-base single crystal superalloy, CMSX-2 was investigated using MBF-80 insert metal. The (100) orientation of bonded specimen was aligned perpendicular to the joint interface. CMSX-2 was bonded at 1523K for 1.8ks in vacuum, optimum bonding condition. The creep rupture strength and rupture lives of the joints were the almost identical to ones of the base metal. SEM observation of the fracture surfaces of joints after creep rupture test revealed that the fracture surfaces classified three types of region, ductile fracture surface, cleavage fracture surface and interfacial fracture surface. The low cycle fatigue properties of the joints were also the same level as those of base metal. The elongation and reduction of area values of joints were comparable to those of base metal while fell down on creep rupture condition of high temperature.

• Journal of Welding and Joining
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• 제19권4호
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• pp.423-428
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• 2001

The bonding phenomena of Ni base single crystal superalloy. CMSX-4 during transient liquid phase(TLP) bonding was investigated using MBF-80 insert metal. Bonding of CMSX-4 was carried out at 1,373∼1,548K for 0∼19.6ks in vacuum. The (001) orientation of each test specimen was aligned perpendicular to the bonding interface. The dissolution width of base metal was increased when the bonding temperature and holding time were increased. The eutectic width diminished linearly with the square root of holding time during isothermal solidification process. Borides were formed in the bonded layer during TLP bonding operation. The solid phase grew epitaxially into the liquid phase from substrates and single crystallization could be readily achieved during the isothermal solidification.