• 제목/요약/키워드: Sound Proof

검색결과 50건 처리시간 0.025초

DESIGN, CONSTRUCTION AND ACOUSTIC PERFORMANCE OF A SOUND-POOOF ENCLOSURE FOR DIESEL GENERATOR-SET

  • Bansal, A.S.
    • 한국음향학회:학술대회논문집
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    • 한국음향학회 1994년도 FIFTH WESTERN PACIFIC REGIONAL ACOUSTICS CONFERENCE SEOUL KOREA
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    • pp.662-667
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    • 1994
  • This paper presents the design and construction details of a soundproof enclosure for housing 20 KVA diesel generator-set. As the generator had to be installed close to the hospital building, it was desirable to reduce the transmission of noise by housing the generator in such an enclosure. The diesel engine being an air cooled one, it was essential to supply fresh air into the enclosure for its cooling. Forced inflow of air is provided through an inlet duct located in such a way that the incoming fresh air is thrown close to the inlet of cooling fan of the engine. The high velocity air stream, which heats up while passing over the engine head, escapes to the atmosphere through a rectangular outlet duct with enlarges inlet that receives hot air from the engine. The air ducts were designed specially and have been provided with acoustic lining for sound absorption. The masonary enclosure has been provided with double glazed fixed windows and double doors. The exhaust pipe of the engine fitted with a muffler has been taken out through the enclosure wall facing away from the hospital. Acoustic performance studies conducted in terms of attenuation provided by the enclosure at different frequencies have also been presented and discussed. The noise control measures adopted for building the sound-proof enclosure have been found to be quite effective as the noise levels inside the hospital building are now within the acceptable limits.

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이중복합 주조체의 제조에 미치는 구성 재질과 주조 조건의 영향 (Influences of Casting Conditions and Constituent Materials on the Production of Duo-castings)

  • 정재영
    • 한국주조공학회지
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    • 제38권1호
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    • pp.16-26
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    • 2018
  • In this study, the effects of the pouring temperature, preheating temperature, surface condition and fraction of the wear resistant part on the production of duo-castings were investigated using a high Cr white cast iron with excellent abrasion resistance and a low Cr alloy steel with good toughness. The constituent materials of the duo-castings were designed to have high hardness, fracture toughness and abrasive wear resistance for the replacement of high Mn alloy steels with low abrasive wear resistance. In particular, the amount of abrasive wear of 17% Cr white cast iron was about 1/20 of that of high Mn alloy steel. There was an intermediate area of about 3mm due to local melting at the bonding interface of the duo-castings. These intermediate regions were different from those of the constituent materials in chemical composition and microstructure. This region led to fracture within the wear resistant part rather than at the bonding interface in the bending strength test. The bending fracture strengths were 516-824 MPa, which were equivalent to the bending proof strength of high Mn steel. The effects of various casting conditions on the duo-cast behavior were studied by simple pouring of low Cr alloy steel melt, but the results proved practically impossible to manufacture duo-castings with a sound bonding interface. However, the external heating method was suitable for the production of duo-castings with a sound bonding interface.

애완동물과의 공생을 고려한 공동주택 계획요소 연구 (A Study on the Planning Elements for Apartment Residents Living with Companion Animals)

  • 김선아;이연숙;이수진
    • KIEAE Journal
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    • 제5권2호
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    • pp.27-34
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    • 2005
  • The purpose of this study were to examine actual conditions of apartment residents living with their companion animals and to identify their residential stress and needs of planning elements under those conditions. Questionnaire survey was adopted in this study, and 100 cases were used for data analysis. The subjects for this study were limited to the residents breeding pets in their apartments. The results of this study are as follows: Most of the residents share their living spaces with pets together like their family without spatial restrictions. They indicated problems related to breeding pets in their residence such as walking the dog, cleaning home, leaving pets alone, noise and unpleasant smell. However, they didn't seem to be stressed a lot for their living environments. In terms of residential planning elements, floor plans for effective natural ventilation, balcony with sufficient sunlight, sound proof system, easy-maintenance interior material, unlash area, rubbish bin, mechanical ventilation and central vacuum system and safe electric outlet were highly indicated.

휴대용 자동청력진단기기 개발 (Development of a portable automatic hearing screener)

  • 노형욱;이탁형;김종욱;양동인;차은종;김덕원
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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    • pp.129-131
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    • 2009
  • Hearing loss is one of the most common birth defects among infants. Most hearing-impaired children are not diagnosed until one to three years of age, which is too late to treat for normal speech and language development. If a hearing impairment is identified and treated in its early stage, child's speech and language skills could be comparable to his or her normal-hearing peers. In this study, we applied the 'Fsp' method to distinguish between normal and impaired hearing. We have developed a battery-operated portable A - ABR(automated auditory brain stem response) system that automatically detects hearing impairment for neonates or infants in a nursery room, as well as in a sound-proof room. We partially validated the accuracy of the system in five normal-hearing adults.

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초경량 콘크리트 흡음재의 음향특성에 관한 연구 (A Study on the Acoustical Characteristic of a Ultra Lightweight Concrete Absorber)

  • 정성수;김용태;이원암;한기석
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 춘계학술대회논문집
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    • pp.594-599
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    • 2000
  • Two basic acoustic quantities, the characteristic impedances and the propagation constants, of the two different ultra lightweight concrete absorbers were examined with impedance tube method. A transmission loss was tested and compared with theoretical values. The results show that these kinds of sample have proper sound absorption and transmission loss capabilities. It means that they can be used in various fields where noise proof is needed.

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DIGITAL WATERMARK REPRODUCTION IMAGE ATTESTATION THAT USES PHASE ONLY CORRELATION METHOD

  • Inaba, Fumiya;Tanaka, Ken-Ichi
    • 한국방송∙미디어공학회:학술대회논문집
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    • 한국방송공학회 2009년도 IWAIT
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    • pp.508-511
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    • 2009
  • The infringement of the copyright is a problem by the distribution of digital contents copied illegally. The digital watermark is expected as a thing preventing unjust copying by burying information in digital data such as image, animation, the sound, TV, radio and movies. [1] [2]But a noise is included in a digital watermark reproduction image. So there is the case that the certification of the reproduction image has difficulty with. If a computer cannot recognize the information reproduced from digital watermarking, the information does not have a meaning. This paper aimed at improvement of the proof of a digital-watermarking reproduction image. And it is verified whether the difference of the form of a character affects the degree of correlation.

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생태방음벽의 형태에 따른 활착율에 관한 연구 (Type of ecological sound proof wall based on their plant survival)

  • 한세권;조해용;사리타 버셀
    • 한국산학기술학회:학술대회논문집
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    • 한국산학기술학회 2010년도 춘계학술발표논문집 2부
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    • pp.1101-1104
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    • 2010
  • 실험에 사용된 식생기반재는 일반토양, 비료, 인공토양을 혼합하여 사용하였다. 기반재는 식물이 뿌리를 발생시켜 착근하는 과정초기에 필요한 비료성분을 즉각적으로 공급하는 화학비료와 장기간에 걸쳐 공급하는 유기물 비료로 구성되었다. 식생기반재 발아실험에 이용된 36종의 종자들은 균일하게 도포한 후 1cm 정도 배합토로 덮어 주었다. 본 실험에서는 배합토의 주성분인 일반토양과 유기물의 비율을 8:2로 하여 실험하였다. 또한 식물의 활착과 피복율을 높이기 위해 Seed Spray를 이용하여 다시 한 번 종자를 분사하여 실험하였다.

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도로방음벽용 조명기구 반사판의 개발 (The Development of a Luminaires Reflector for Sound proof wall)

  • 정승균;조문성;김훈
    • 한국조명전기설비학회:학술대회논문집
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    • 한국조명전기설비학회 2005년도 학술대회 논문집
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    • pp.201-205
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    • 2005
  • 도로조명은 야간에 운전자에게 안락함과 안전한 운행을 도울 수 있도록 설치가 이루어져야한다. 최근 늘어나는 자가용에 의해서 주택가나 공공장소에 발생하는 소음을 감소시키기 위하여 도로 위 필요지점들에 방음벽이 설치되어지고 있다. 그러나 현재 이에 적합한 형태의 조명기구가 개발되지 못한 상황이며, 이에 따라서 방음벽에 설치가 가능한 도로조명기구의 반사판을 개발하였다. 개발된 반사판은 도로에 대해 연직방향으로 위치한 방음벽에 그대로 설치되어질 수 있는 형태이며, 도로조명기준에 맞추어 전반 균제도 0.4와 차선 축 균제도 0.7 이상을 만족할 수 있도록 설계되었고, 단위 면적당 소비전력 $1.18[W/m^2]$의 효과를 얻었다.

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DCT를 이용한 오일 바킹제품의 선별 시스템 개발 (System Development of Selection for Oil Ring Product Using DCT)

  • 김석현
    • 한국산업정보학회논문지
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    • 제7권4호
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    • pp.83-89
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    • 2002
  • 자동차의 바킹류 및 방음고무는 자동차의 소음 및 오일등 각종유액의 누설의 대부분을 차지하고 있기 때문에 자동차의 생명연장에 필수적인 부품이다. 현재까지 선별시스템의 고가로 인해서 대부분의 선별이 수작업으로 이루어져 왔다. 이는 피로누적에 의한 오류가 많을 수 있고 제품의 신뢰도에 치명적일 수 있다. 선별 시스템을 완전 자동화 하므로서 공정개선 및 인건비 절감, 신뢰도 개선의 효과가 있다. 이 연구는 앞으로 이들 고무 제품의 검사 장비의 자동화를 이루는 기반을 만든다고 할 수 있다. 특히 컨베이어 벨트를 타고 흐르는 부품을 제어하는 부분과, 움직이는 물체의 타이밍을 설계하여 영상획득하여 내부 불량 제품에 DCT(이산여현변환)를 적용하여 선별시스템을 만들었다.

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영어 문장 말 폐쇄음의 파열 양상 (Phonetic Factors Conditioning the Release of English Sentence-Final Stops)

  • 김다히
    • 대한음성학회지:말소리
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    • 제53호
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    • pp.1-16
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    • 2005
  • This experimental study aims to test the hypothesis that the occurrence of English sentence-final stop release is, at least, partly predictable by examining its phonetic context. 10 native(5 male and 5 female) speakers of American English recorded, in a sound-proof booth, sentences excerpted from novels and the natural documents on the World Wide Web. Based on the waveforms and spectrograms of the recorded sentences, judgements of the release of a sentence-final stop were made. If the aperiodic energy of a given final stop lasted more than .015 second, it was considered to be "released." The result reveals that English sentence-final stops tend to be released when they are 1) velar consonants, 2) preceeded by tense vowels, and 3) coda consonants of content words. The phonetic environment in which final stops are often released can be characterized by the articulatory comfortableness and the need for release burst noise, without which the final stops may not be correctly perceived. By examining the release of English final stops, it is concluded that the phonological events, which had been considered to occur rather "randomly," in fact, reflect the universal tendency of human speech: to minimize the speakers' and hearers' effort.

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