• 한국음향학회지
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• 제43권1호
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• pp.39-48
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• 2024

자동차용 경음기는 운전자 간의 의사소통 수단이자 보행자에게 사전에 경각심을 불러일으키는 부품으로서 안전상 중요한 역할을 한다. 유한 요소 방법과 전기 회로 모델을 활용한 자동차용 경음기의 모델링 연구와 혼의 음향학적 특성을 분석한 연구들이 수행되었으나, 트럼펫 혼의 작동 주파수 설계 방법에 대한 연구는 미비하다. 본 논문에서는 트럼펫 혼의 진동부가 결정되었을 때, 쉘의 음향 리액턴스에 따른 작동 주파수를 예측하는 설계 방법을 제시하고자 한다. 음향부에서는 지수 혼과 도파관이 결합된 혼에 대해 다루었고, 임피던스 튜브 실험을 통해 도파관의 입구 음향 리액턴스는 해석 결과와 유사함을 확인했다. COMSOL Multiphysics 유한 요소 수치 해석 모델을 이용하여 자동차용 경음기의 공진 주파수를 예측했고, 음압 실험을 통해 설계된 혼의 작동 주파수를 측정하여 설계 방법을 검증했다. 음압 실험은 홀더를 제외하고 DC 전압을 12 [V] 인가하여 반무향실 환경에서 측정한 결과, 설계 작동 주파수와 비교하여 수 [Hz] 내에서 정확하게 공진이 발생했다. 본 논문에서는 혼의 음향 리액턴스 관점에서 자동차용 트럼펫 혼의 설계 방법을 살펴보았고, 혼을 포함한 시스템을 설계할 때 유용하게 활용될 수 있을 것으로 기대한다.

• 천문학회보
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• 제42권2호
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• pp.57.3-58
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• 2017

We report the detailed design of an unprecedented wideband(band7+8) corrugated feed horn in ASTE focal plane array aiming for future ALMA receiver. We have found that such design constraints as return loss, cross-polarization level, beam width and phase curvature can be controlled by optimizing critical corrugation parameters at the throat and flare region of the horn. The success of optimization manifest itself through simulated aperture effciency over 80 % at the entire frequency range. Physical implications of the resulting corrugation parameters are discussed.

• 천문학회보
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• 제41권2호
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• pp.66.2-66.2
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• 2016

KASI and NAOJ are making collaborating efforts to implement faster mapping capability into the new 275-500 GHz Atacama Submillimeter Telescope Experiment focal plane array (FPA). Feed horn antenna is one of critical parts of the FPA. Required fractional bandwidth is almost 60 % while that of traditional conical horn is less than 50 %. Therefore, to achieve this wideband performance, we adopted a horn of which the corrugation depths have a longitudinal profile. A profiled horn has features not only of wide bandwidth but also of shorter length compared to a linear-tapered corrugated horn, and lower cost fabrication with less error can be feasible. In our design process the flare region is represented by a cubic splined curve with several parameters. Parameters of the flare region and each dimension of the throat region are optimized by a differential evolution algorithm to keep >20 dB return loss and >30 dB maximum cross-polarization level over the operation bandwidth. To evaluate RF performance of the horn generated by the optimizer, we used a commercial mode matching software, WASP-NET. Also, Gaussian beam (GB) masks to far fields were applied to give better GB behavior over frequencies. The optimized design shows >23 dB return loss and >33 dB maximum cross-polarization level over the whole band. Gaussicity of the horn is over 96.6 %. The length of the horn is 12.5 mm which is just 57 % of the ALMA band 8 feed horn (21.96 mm).

• 한방재활의학과학회지
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• 제21권2호
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• pp.211-226
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• 2011

Objectives : The purpose of this study is to establish literatural evidence about traditional Korean medical physiotherapy through literatural review. Methods : Applicable paragraphs which were related to the traditional Korean medical physiotherapy were phrased from in "Hwang-je-nae-gyung(黃帝內經)", "Yumun-sa-chin(儒門事親)", "Geum-guei-yo-ryack(金匱要略)", "Eui-hack-ip-mun(醫學入門)", "Gyung-ack-jeon-seo(景岳全書)", "Eui-hack-gang-mock(醫學綱目)", "Dong-eui-bo-gam(東醫寶鑑)" where were archiving of Oriental or Korean medicine literatures. Searched paragraphs were analysed for establishing historical and theoretical bases of Korean medical physiotherapy. Results : 1. Theromtherapy is originated from yu(熨), hot hand, warm, water bath, warm earth, fumigation, lamp, torchlight and brazier. Matching indications are various musculoskeletal pain and diseases, skin diseases such as chronic inflammation, frostbite, gynecological and urogenital diseases such as uterine myoma, lower abdominal pain, metrorrhagia, breast diseases, digestive tract diseases such as vomiting, diarrhea, stomachache and also it treats cardiovascular disease. Other matching indications are sunstroke, rhinorrhea, psycosis and anal pain. And it used helping acupuncture therapy. 2. Cryotherapy is originated from lengfu(冷敷), lengtie(冷貼), cold stone and cold water. Matching indications are various fever disease, skin diseases such as acute inflammation, wound, fever skin disease, otorhinolaryngological diseases such as acute sore throat, otitis, stomatitis, nasal bleeding and contusions, abrasions, burn and dysuria. In addition, it treats extremity coldness, chillness, stomachache caused to accumulate fever. 3. Physiotherapy by circulating meridian system is originated from manipulation such as pushing, massage and beating to therapy point. Matching indications are musculoskeletal diseases such as various muscular pain, heavy sensation, convulsion, urogenital diseases such as dysuria, lower abdomen pain, digestive tract diseases such as stomachache, and paralysis due to blocked meridian system. And other matching indications are psycosis, leprosy, hypoesthesia, acute stroke. In addition it helps other therapy methods. In addition, the power of manipulation classify to strengthen and reduce. 4. Physiotherapy by balancing meridian system is originated from sunshine, magnet, horn, bamboo and tube. Sunshine helps improving self's care and cure inflammatory skin disease. Magnet's matching indications are paralysis, various injuries, abscess, fever and eye disease. Cupping therapy treats to skin diseases and internal diseases such as tuberculosis. Conclusions : Traditional Korean medical physiotherapy was widely used in traditional Korean medicine since ancient time based on the traditional Korean medical principle and anatomical knowledge. With modern physiotherapy and traditional Korean medicine together, effects of treatment are enhanced. And traditional Korean medical physiotherapy is appropriated to world physiotherapy's expectation.