• 제목/요약/키워드: backing

검색결과 235건 처리시간 0.031초

Development of an Impedance Matching Layer in an Ultrasound Transducer with Gradient Properties

  • Jeong, Jihoon
    • 센서학회지
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    • 제27권6호
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    • pp.374-379
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    • 2018
  • The piezocomposite transducer is widely used because it is highly efficient in transforming electric energy into mechanical energy, and its frequency range is broader than that of other types of ultrasound transducers. A general piezocomposite transducer is composed of an acoustic lens, impedance matching layers, piezoelectric materials, and backing layers. When an input voltage is applied to a piezoelectric material as an active material, it generates sound waves while vibrating. At that time, an impedance matching layer helps the sound waves to propagate forward while reducing the impedance mismatch that may occur at the interface between the active material and its front material. The impedance mismatch has a negative effect on the signal of an ultrasound transducer; thus, it is important to design a matching layer to overcome the issue. In this study, an optimized feature of a matching layer with gradient properties is studied. An objective function is defined to minimize both the average and the deviation of the reflection coefficients that are functions of the frequencies. As a result, an improvement in the signal characteristics with respect to the sensitivity and bandwidth is reported.

압축전담 교량 내진보강공법 개발 연구 (Development of Compression-Only Bridge Seismic Reinforcement Method)

  • 장유식;윤원섭;유광호
    • 한국산업융합학회 논문집
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    • 제25권6_3호
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    • pp.1221-1230
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    • 2022
  • In this study, a seismic reinforcement method was studied to improve the seismic performance of aged bridges. The construction method developed in this study is a compression-only bridge seismic reinforcement method, and has excellent economic feasibility and workability compared to existing construction methods. In the case of aged bridges, there was an advantage that could compensate for the disadvantages that it was difficult to apply the existing reinforcement method. For the newly developed method, the effect of reinforcement was analyzed through resin analysis. As a result of the analysis, when the reinforcement was applied, the axial reinforcement effect was excellent, and the field applicability was excellent as it showed better results than the existing seismic isolation backing method.

한국중년여성의 시집살이 경험 (The lived Experience of the Middle Aged Korean Women's living with Mothers in Law(=Sigipsalee))

  • 한혜실;김애정;양복순
    • 부모자녀건강학회지
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    • 제7권2호
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    • pp.182-200
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    • 2004
  • Purpose: This study is to explore the essence of those lives who have been living with their mothers- in- law for more than 10years since their marriage by applying Van Manen's hermeneutic phenomenological methodology. It consists of four steps such as concentration on the nature of lived experience, existential research, hermeneutic phenomenological reflection and hermeneutic phenomenological writing. Method: Six middle aged participants who have been living with mothers- in- law in middle size of cities were interviewed and observed with their written consent for one month from 20, April. 2000 to 20 May 2000. To expand insight by analyzing sayings, folks stories, writings, etymology of sigipsalee relevant to it were collected and reviewed. Result: Five essential themes were derived by repeated reviewing the transcription of those interview such as difficulty living with endless heart distress, feeling oppressed, feeling deeply lonely, having a stronger backing as time passes, in turn harmonizing with each other. On the basis of the five essential theme hermeneutic phenomenological writing was done as follow. Participants lived lives filled with uneasy feeling from the newly formed relationship among in laws but especially with mothers- in- law. Participants did their best to be acknowledged found that at a significant moment during family event they would be treated as strangers so that they felt isolated and alone. Mothers in laws played a dominant role in most of family decision even buying their children's clothes. Mother in laws rarely complemented them so that they felt inferior as a person. As time passes. Mothers-in-law and daughters-in-law become adjusted to this lifestyle with each other and assumed a more mature relationship which includes a mutual respect thus better harmony. Participants become to have stronger backing so that they express their opinion to mothers-inlaw. With time both of them are getting old, participants show form of pity to their mothers-in- law. Sometimes participant surprise themselves by noticing a change in their behavior to the same pattern Mothers-in-law have showed them. Conclusion: Although generalizations have limitations, findings resulting from the study will enrich family nursing knowledge and understanding the problems when living with mothers-in- law in the same house. It will give a cleared view of problems faced by middle aged korean women in the Korean patriarchal culture. Researchers have recommended to study experiences of married young adult korean women's generation and the findings compared with this study to show trends and changes.

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가평 현등사 수월관음도의 안료분석 및 보존방법 (Pigment Analysis and Conservation Method of Avalokitesvara in Potalaka of Hyeondeungsa, Gapyeong)

  • 서정호;차병갑;정희수
    • 보존과학회지
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    • 제27권2호
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    • pp.223-229
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    • 2011
  • 불화 문화재는 재료의 특성과 환경적 요인에 의한 색의 변화와 박락현상을 피할 수 없다. 특히 안료 표면에 발생하는 미세한 균열과 탈색 현상의 시작은 곧바로 유물 전체의 안정성이 현저히 급감하는 것으로서, 각별한 조치가 필요하다. 따라서 이 연구는 가평 현등사 수월관음도(경기도무형문화재 제198호)의 보존처리에 관한 것이며 유물 손상 부위를 보존처리하고 안정화시키기 위해 배접과 색맞춤을 실시하고, 안료의 과학적 분석을 수행하였다. XRF, 영상 현미경, FT-IR(자외선 분광 분석법)를 통한 비파괴 분석을 실시하여 유물에 사용한 한지의 재질과 안료의 성분 및 그 특성에 대해 조사하였다. 그 결과 현등사 수월관음도의 한지에서는 우리나라 전통 한지와 일치하는 FT-IR 스펙트럼이 검출되었고, 백색 안료위에 엷은 층을 이루고 있는 흑색 안료는 XRF와 FT-IR로 확인되지 않는 먹이나 그을음 등의 탄소화합물로 추정할 수 있었다. 또한 백색 안료는 Pb와 탄산염을 포함하는 연백($PbCO_3{\cdot}Pb(OH)_2$)이며, 현미경 관찰을 통해 청색 안료의 결정 상태를 확인한 결과 크고 작은 입자 분포를 보였다. XRF 분석 값은 Cu와 Pb 모두 높게 검출된 것으로 보아 청색의 경우 석청과 연백이 혼합되어 사용된 것을 알 수 있었다.

조림·육림정책에 대한 인식도 평가 연구 (A Study of Evaluation for Reforestation and Silviculture Policy in Korea)

  • 남성현;김세빈;권기원;전현선
    • 한국산림과학회지
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    • 제97권1호
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    • pp.10-21
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    • 2008
  • 본 연구는 조림 육림정책에 대하여 정책수립 과정에서 문제인식의 적합성, 정책결정 및 집행의 합리성, 정책의 지지도, 정책의 결과와 효과에 대해 측정, 분석하고 바람직한 정책대안을 제시하는 데 목적이 있다. 조사대상은 조림 육림정책에 직 간접적으로 관여하거나 영향을 받는 공무원과 민간인을 대상으로 598명을 임의 추출하였다. 정책이 합리적으로 결정되기 위해서는 문제인식이 정확히 되어야 하는데, 조림 육림정책의 문제인식은 대부분 긍정적으로 평가되었다. 다만, 조림수종을 침엽수 위주에서 활엽수 위주로 전환해야 한다는 점은 긍정적 평가 57.0%, 부정적 평가가 38.1%로서 보다 신중한 접근이 필요하다. 조림 육림사업 시 69.6%가 기술적으로 어려움이 있다고 평가되어 이는 전문교육 등을 통해 담당자들의 기술력을 향상시켜 나가야 할 것이다. 또한 조림 육림정책 결정의 적합성과 집행의 합리성에 대해서도 대부분 긍정적으로 평가되었으나 다른 산림정책과의 상충이 있다는 부정적인 평가에 대해서는 앞으로 이러한 정책들이 산림산업의 경쟁력 제고, 산림휴양문화 증진 정책 등 다른 정책과 상충되지 않도록 하고, 조림 육림사업 담당자에게 재량권 확대방안을 강구하여야 할 것이다. 조림 육림정책에 대한 외부 지지도와 정책의 결과 및 효과에 대해서도 대체로 긍정적인 평가를 하고 있다. 그러나 정치권의 지지도가 낮은 것으로 평가되었고, 조림 육림정책이 경제적 기능 증진에 대한 기여도가 낮게 평가되었다. 따라서 정치권에 대한 홍보를 강화해 나가고 산림의 복합경영이나 임산소득 작목의 개발 등으로 경제적 기능 증진 방안을 적극 강구하여야 할 것이다.

조사광이 통과하는 치질의 두께와 광조사시간에 따른 광중합형 복합레진의 중합률에 관한 연구 (A STUDY ON THE DEGREE OF CONVERSION OF LIGHT CURING COMPOSITE RESIN ACCORDING TO THE THICKNESS OF TOOTH STRUCTURE PENETRATED BY LIGHT AND APPLIED LIGHT CURING TIME)

  • 황기환;장인호;이세준;이광원
    • Restorative Dentistry and Endodontics
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    • 제27권1호
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    • pp.16-23
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    • 2002
  • Physical properties of composite resins such as strength, resistance to wear, discoloration, etc depend on the degree of conversion of the resin components. The purpose of this study was to evaluate the degree of conversion of the composite resins according to the thickness of tooth structure penetrated by light and applied light curing time. The coronal portions of extracted human teeth (one anterior tooth, three posterior tooth) was embedded by pink denture material. the mounted teeth were cut into three illumination sections (1mm thickness enamel section, 1mm thickness dentin section, 2mm thicknes dentin section) and one backing section with cutting wheel. Thin resin films were made by using 6kg pressure between slide glass during 5 minutes Thin resin film was light cured on coupled illumination section during 40sec, 80sec and 120sec. each illumination section was coupled as follows; no tooth structure(X), ename section(E), enamel section + 1mm dentin section(ED1), enamel section + 2mm dentin section(ED2), enamel section + 1mm dentin section + 2mm dentin section(EDD). To simulate the clinical situation more closely, thin resin films was cured against a backing section of tooth structure. The degree of conversion of carbon double bonds to single bonds in the resin films were examined by means of Fourier Transform Infrared Spectrometer. The results were obtained as follows ; 1 As curing time was increased, conversion rate was increased and as tooth thickness which was penetrated by curing light was increased, conversion rate was decreased. 2. At all tooth thickness groups, conversion rate between 80sec and 120sec was not significantly increased(P>0.05). 3. At 40sec group and 80sec, conversion rate between no tooth structure(X) group and 1mm enamel section(E) group was not significantly decreased(P>0.05). 4. At 80sec group and 120sec, conversion rate between 1mm enamel section(E) group and 1mm enamel section + 1mm dentin section(ED1) group was not significantly decreased(P>0.05).

스마트폰 MIDI 재생 기능을 활용한 속도 증가 악기 연습 애플리케이션 개발 (Development of an Automatic Tempo-Regulating Smartphone Application Using MIDI Playback Functions For Musical Instrument Practice)

  • 심인섭
    • 한국엔터테인먼트산업학회논문지
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    • 제13권8호
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    • pp.143-150
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    • 2019
  • 악기 연주는 언제나 많은 사람들의 취미로 자리하고 있다. 그러나 음악적 심미성을 만족시키고 연주를 통한 즐거움을 느낄 수 있게 되기까지는 지루하고 고된 연습 과정이 필요하다. 이러한 반복적이고 지루한 연습 과정은 악기 연주에 커다란 진입 장벽이 되고 있으며 수많은 교육자들이 학생들을 위해 이러한 과정을 더욱 쉽고 재미있게 만들기 위해 많은 연구와 노력을 기울이고 있다. 또한, 학생들의 흥미와 재미를 지속시키기 위해서 다양한 미디어를 통한 연습 도구들이 개발되고 있으며 이러한 콘텐츠들의 핵심 요소들은 주로 학생들의 수준을 고려한 반주의 속도조절과 연주의 재미를 느낄 수 있게 하는 합주 요소제공으로 볼 수 있다. 본 연구에서는 이러한 음악 교육용 콘텐츠, 혹은 오락 콘텐츠 개발을 위해 현대 사회에 가장 많이 사용되고 있는 스마트폰 애플리케이션에서 속도와 음정을 조절할 수 있는 다양한 MIDI 재생 기법에 대해 연구하고 비교했다. 또한, 대표적인 스마트폰 운영체제인 Android OS와 iOS에 서로 다른 기법을 적용하여 속도가 자동으로 증가하는 드럼 루프 메트로놈인 Upbeat를 개발하고 출시했다.

1:50 다목적홀의 음향평가를 위한 축소모형재료의 선정 (Selection of Scale Model Materials for Acoustical Evaluation of 1:50 Multipurpose Halls)

  • 전진용;김정준;김용희
    • 한국음향학회지
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    • 제28권8호
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    • pp.781-789
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    • 2009
  • 다목적홀의 음향을 1:50 축소모형으로 예측 및 평가하기 위해 필요한 모형재료의 구성과 흡음특성에 대해 연구하였다. 실제 홀에서의 반사면 및 가변음항요소, 객석의 설계요소별 흡음특성 (125Hz-lkHz 평균)을 기준으로 축소모형의 형상과 재질을 선정하였으며, 흡음율은 상사의 법칙과 ISO 354를 준용하여 측정하였다. 그 결과, 주벽체의 평균흡음율은 0.08로 래커 코팅된 MDF나 아크릴이 적합하며, 객석 의자, 관객 및 연주자 평균흡음율은 각각 0.64, 0.74와 0.45를 목표로 할때 목재, 흡음천과 폼보드를 조합하여 흡음률을 재현하였다. 흡음커튼과 배너는 적용부위 및 단면설계에 따라 흡음재의 마운팅 방법을 선택하였으며, 배면공기층이 없는 상태 (A형 마운팅)에서의 평균흡음율이 0.42, 0.9 m 배면공기층 조건에서 시료 양단이 고정된 상태 (E형 마운팅)에서는 0.47, 천장에 매단 상태 (G형 마운팅)에서는 0.45로 나타났다. 특히, 배면공기층의 증가에 의해 저주파 대역 흡음력이 증가하였다. 스테이지 하우스 내부는 평균흡음율 0.68의 Fiber glass board 시공을 예상하여 흡음재와 스피커망 원단을 조합하여 재현하였다. 본 연구에서 도출된 모형 재료의 형상과 흡음특성은 향후 1:50 축소모형으로 다목적홀의 형상에 의한 중주파 대역 이하의 음향예측에 유용하게 활용될 것으로 사료된다.

Effect of Claw Abrasives in Cages on Claw Condition, Feather Cover and Mortality of Laying Hens

  • Glatz, P.C.
    • Asian-Australasian Journal of Animal Sciences
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    • 제17권10호
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    • pp.1465-1471
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    • 2004
  • A trial was conducted to determine the effect of abrasive strips and abrasive paint in layer cages on claw length and claw sharpness, foot condition, feather cover and mortality of hens. During the preparation of the cages for the experiment it was simpler and took less time to apply the pre-prepared paint with a spatula to the egg guard compared to sticking the abrasive strips onto the egg guard. Fitting the strips took longer because it had to be cut from a 25 mm roll, cut into the appropriate lengths, the tape backing removed and then stuck onto the egg guard section. Abrasive paint was more effective as a claw shortener than abrasive strips. The birds using the abrasive paint had the shortest (p<0.05) claw length and lowest (p<0.05) claw sharpness. One of the original reasons for reducing claw length with claw shorteners was to reduce mortality by minimising skin skin abrasions caused by the claws. Surprisingly hen mortality from prolapse and cannibalism was higher (p<0.05) in cages fitted with abrasives. There are no other reports in the literature showing an increase in prolapse and cannibalism from hens using abrasives.

아동친화적 주거환경을 위한 디자인지침 중요도 평가 (Evaluating the Imfortance of the Child-Friendly Planning Guidelines for Residential Environments)

  • 정경숙;이연숙
    • 한국주거학회논문집
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    • 제21권6호
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    • pp.61-69
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    • 2010
  • The purpose of this study was to lay out child-friendly planning guidelines for environments in a bid to create residential environments geared toward backing up children's life. Earlier studies were reviewed to make a literature analysis to find out existing planning guidelines for environments, and small-group workshop was held to formulate down-to-earth planning guidelines. And a survey was conducted on the parents of selected children to assess the importance of the selected planning guidelines. The findings of the study were as follows: First, residential environments were categorized into housing spaces and outdoor playing spaces, and 25 and 28 planning guidelines for each field were prepared respectively. When a survey was implemented, all the 53 planning guidelines were rated as important or very important. Second, the guidelines for safety were considered very important, and the importance of the planning guidelines varied with children's age. The findings of the study suggest that the development of more reinforced criteria for children's safety is required to create child-friendly residential environments.