• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.31 no.7
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• pp.53-64
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• 2002

$CO_2$ 20세기 초 천연 냉매 $CO_2$는 광범위하게 사용되었지만 프레온계 냉매의 출현으로 1940년경부터 $CO_2$냉매는 사용이 제한되었다. 그러나 반 세기 동안 사라졌던 $CO_2$냉매는 1980년 후반에 노르웨이 과학 기술대학 (NTNU)과 북구 최대 민간연구소 (SINTEF)의 Lorentzen 교수에 의해 $CO_2$천연 냉매 사용을 재고하게 되었다. 프레온계 냉매의 환경적 논쟁이 쟁점이 되면서 천연 냉매 사용을 재고하게 되었다. 특히 비가연성과 비유독성으로 인한 $CO_2$냉매가 주목을 받고 있다. 초월임계 사이클레서의 고압 제어에 대한 새로운 개념은 Lorentzen 교수와 동료 연구원에 의해서 특허로 제안되었다. 이에 대한 상업적 권리를 Norsk Hydro사는 1990년에 얻었고,1990년대 초반에 NTNU/SINTEF의 공동 연구개발 프로그램을 통해 기술 경쟁력과 실현 가능성이 검증되었다. 현재 연구소에서는 최초로 초월임계 $CO_2$사이클을 이용한 상업용 온수 열펌프 시스템, 2003년 시작할 연료전지 전기 자동차에 대한 연구를 수행하고 있다. NTNU/SINTEF에서 개발된 $CO_2$기술은 Hydro-SINTEF 공동 벤처 기업인 Shecco기술회사를 통해 제조업자에게 허가된다. 본 고에서는 NTNU/SINTEF에서 수행하였거나 수 중인 과제들을 중심으로 유럽의 $CO_2$시스템의 결과와 주요 개발 범위를 정리하였으며, 특히 작동유체로서의 $CO_2$냉매의 특징을 간단히 설명하고, 온 수 열 펌프, 자동차용 공조기 및 열 펌프, 상업 냉동기 등이 기술되었다. 그 외 압축기 위주의 요소기술 개발에 관한 내용도 기술되었고, 차세대 기술 경향과 전망에 대해서도 제시되었다. 제시되었다.성균 350$\times$$10^4$ CFU균, 방선균 434$\times$$10^4$ CFU균, 진균 676$\times$$10^4$ CFU균으로 진균의 개체수가 비교적 높게 나타났으며, 비산불지역에서는 호기성균 328$\times$$10^4$ CFU균, 방선균 319$\times$$10^4$ CFU균, 진균 461$\times$$10^4$ CFU균으로 진균의 개체수가 높게 나타났다. 토양미생물은 호기성균, 방선균, 진균 모두 비산불지역 보다 산불지역에서 많이 나타났다. 본 조사지역에서 호기성균은 활엽수림보다 침엽수림에서 많게 나타났으며, 방선균과 진균은 침엽수림보다 활엽수림에서 많이 나타났다.효과와 이를 이용한 자기냉동의 방법 그리고 최근에 이루어진 새로운 진전에 대해 소개하고 공기조화 및 냉동분야에의 적용 가능성을 전망해 보고자 한다.및 도입 등 선주들에게 다양한 선박건조자금을 제공하여 내수기반 확충에도 노력해야 할 것 이다.있었다., 인삼이 성장될 때 부분적인 영양상태의 불충분이나 기후 등에 따른 영향을 받을 수 있기 때문에 앞으로 이에 대한 많은 연구가 이루어져야할 것으로 판단된다.태에도 불구하고 [-wh]의미의 겹의문사는 병렬적 관계의 합성어가 아니라 내부구조를 지니지 않은 단순한 단어(minimal $X^{0}$ elements)로 가정한다. 즉, [+wh] 의미의 겹의문사는 동일한 구성요 소를 지닌 병렬적 합성어([$[W1]_{XO-}$ $[W1]_{XO}$ ]$_{XO}$)로 그리고 [-wh] 의미의 겹의문사는 중복된 발은을 지닌 한 단어로 ([W]$_{XO}$ )

• Journal of The Korean Association For Science Education
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• v.37 no.6
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• pp.1005-1014
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• 2017

Focusing on the role of the science museum as an institution to improve the scientific literacy of the public, this study investigated public perception and behavior about science museum to know how much science museums affect the public by using social media big data analysis. For this purpose, we extracted texts containing 'science museum' in Naver blogs and Twitter, analyzed them by using network, frequency, co-ocurrence, and semantics analysis and compared them with the results in English speaking countries. As a result, blogs were mainly concerned with science museum among parents who have young children, while in Twitter posts from many students who visited as a group appeared. Therefore, the Korean public used science museum mainly as a space for children's experience, and in this case, programs and exhibitions of science museums are perceived positively. On the other hand, students who visited as a group showed some negative emotions. The result of comparison with the cases of foreign countries in terms of the function of the third generation science museum such as communications with the science museum and the public and the participation of the public in science, the Korean public hardly mentioned the scientific contents, words related to communications such as 'argue', and curators or staff after visiting the science museum. In contrast to many verbs related to meaningful activities such as 'learn', 'participate', 'listen', 'read', 'ask', 'think' appeared in English, only a small number of verbs include 'ask' and 'thin' appeared in Korean. Therefore, science museum need to improve impression, communicating with public, and involving activity with impact and variety after visit.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.5
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• pp.431-443
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• 2014

In this paper case studies of artificial ground freezing, which have not been applied in Korea, have been investigated for the water cut-off in a subsea tunnel under high water pressure and the most commonly used cooling mediums of brine and liquid nitrogen are examined. Since sea water with pressure has the lower freezing point than pure water, the lower temperature cooling medium is required in the application of subsea tunnel. Also, the cooling medium must have refrigeration safety and is able to reduce executing time. Brine freezing system can reuse cooling medium and is safer than liquid nitrogen freezing. But it takes more time to freeze ground and needs complex circulation plants. On the other hand, liquid nitrogen freezing system can't recycle cooling medium and may cause breathing problems or asphyxiation through oxygen deficiency. But, freezing with liquid nitrogen is fast and requires simple refrigeration equipment. Principal elements of design for ground freezing in subsea tunnel have been extracted and these elements are needed further research.

• Applied Microscopy
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• v.30 no.1
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• pp.11-20
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• 2000

The morphological changes in normal and weathering hair shafts of the human scalp were investigated by using the transmission and scanning electron microscopes. The hair shaft composed of cuticular layer, cortex and medula. The surface of normal hairs are smooth and covered by imbricated cuticular scales. The cuticular layer consists of five to seven cuticle cells. These cells, which are flat and thin, measuring about $100{\mu}m$ long and $0.4{\mu}m$ thick, appears intercellular membrane complex in diameter 25 nm. The cortex composed of melanin granules and cornified cells, which multicomponent concentric microfibrils in diameter about 8 nm give rise to macrofibrils in diameter $0.5{\mu}m$ to $0.8{\mu}m$ encased in limiting membrane. The melanin granules are spherical shaped about $0.5{\mu}m$ in size and scattered between macrofibrils. The medulla in the normal hairs are $16{\mu}m$ in diameter centrally region of cortex. Normal hair shafts undergo progressive degenerative changes due to a variety of environmental insults. In the initial weathering process of hair, the cuticular scales became irregularly raised and broken, and then cuticle cells formed cytoplasmic vacuolation, following dissociated intercellular membrane complex, ultimately entirely lost and nuded cortex. Occasionally, transverse fissures were seen at hair shafts indicating that the hairs were deteriorated. Complete removal of the cuticular layer in the heavily damaged cortex portions appeared splitting of the cortical cell into its macrofibrils and scattering of melanin granules.

• Korean Educational Research Journal
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• v.42 no.1
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• pp.35-72
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• 2021

This study is to form develops an effective teaching method centered on the Korean "symbol adverb + predicate" type, helping Chinese students to learn Korean to communicate more accurately when expressing detailed complex feelings and various emotions.Manyforeignlanguage learners try to memorize individual words when they acquire the new vocabulary, this may lead to a problematic in that they cannot use Korean vocabulary accurately and naturally because they do not value the combination of vocabulary words. Since symbolic adverbs are not used in isolation and being frequently used with certain vocabulary words, it is more effective to teach them in the form of instruct learners using "symbol adverb + predicate" forms rather than individual vocabulary words. Accordingly, this research considers a particular vocabulary following symbolic adverbs or vocabulary groups with common semantic qualities that could be frequently introduced. Seven Korean language textbooks used by university in domestic Korea and China are compared and analyzed to reveal the aspects of differences in the use of descriptive words after symbolic adverbs. Finally, based on the textbook analysis results, the government propose a plan to improve the Korean "symbol adverb + predicate" type for Chinese learners. However, this study was limit to being unable to present specific educational measures for Chinese learners in the form of "symbol adverb + predicate". This is expected to complement the limitations of this study in subsequent studies, and lead to more specific discussions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.514-523
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• 2021

Recently, the proliferation of mobile simple payment services has been increasingly affecting people's lives. In addition, the increase in research from both China and Korea shows that the continuous development of simple mobile payment services will be very important in the future. The blog posts mentioning Kakao Pay and Alipay were collected, and keyword analysis was performed to investigate differences in consumers' responses to Kakao Pay and Alipay on social media. The frequency of keywords for each part of speech and the frequency of co-occurred words mentioned in one sentence were analyzed. Specifically, common words that appear in both Kakao Pay and Alipay blogs were extracted. The cooccurred words were analyzed to examine how different reactions were made on the same subject. As a result of the analysis, there were concerns among consumers about the trust of Kakao Pay and Alipay's benefits. For a mobile payment service to become competitive, it is necessary to add various additional services or solve security problems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6446-6451
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• 2014

Pneumatic motors are quite attractive for many applications because of their competitive price, light-weight, easy assembly, safety in hazardous areas as well as other features, such as a good force/weight ratio and operation in exceptionally harsh environments. In contrast to these advantages, pneumatic motors have limited use in applications, particularly those requiring a fast and precise response. These undesirable characteristics are due to the high compressibility of air and from the nonlinearities in pneumatic systems. This paper presents the sliding mode controller based on 3-loop(SMCB3L), which increases the load stiffness to control the rotation angle of a pneumatic motor. The characteristics for the step responses and load disturbances of the proposed controller were compared with the conventional PID controller. The experimental results showed that a properly designed SMCB3L is capable of high positioning accuracy within ${\pm}0.05mm$. Furthermore, the load stiffness of the SMCB3L can be improved 3.5 fold compared to that of PID controllers.

• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.334-339
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• 2008

요즈음 각종 미디어를 통해 '디지로그' 라는 신조어가 주목 받고 있다. 디지로그의 핵심은 디지털 기반의 이분법적인 사고의 틀을 보완하기 위해 아날로그적인 감성의 도입을 의미한다. 이는 기능중심적인사고로 해결할 수 없는 인간과 컴퓨터의 간극을 새롭게 조명할 수 있는 기회를 제공함으로서 HCI 문제의 새로운 대안으로 떠오르고 있다. 기존 생활가전제품 인터페이스의 중요한 목적은 사용성, 유용성과 같은 기능적인 측면 이었다. 이는 제품자체의 목적을 그 기능에 국한하였기 때문이다. 하지만 현재 에어컨, 냉장고와 같은 생활 가전제품들의 위상은 기능을 넘어 집안의 인테리어의 요소로써의 역할 뿐만 아니라 자신을 대변 할 수 있는 혹은 과시하고 싶은 명품 이미지로써 점차 자리잡기 시작하였다. 또한 TFT Color LCD의 도입은 제품의 상태를 단순히 전달해 주는 단계를 벗어나 심미적인 표현까지 가능하게 해주었다. 이를 계기로 수채화 표현기법과 같은 아날로그 메타포를 활용한 감성적 인터페이스가 시도될 수 있었다. 아날로그 메다포를 활용한 디지털 가전 인터페이스의 첫 번째 단계는 스타일이다. 아날로그적인 스타일을 가장 대표적으로 보여주는 것은 바로 회화영역이다. 에어컨 공기청정기능의 프로그레시브 영역에 수채화로 표현된 산과 들을 보여줌으로서 인터페이스가 하나의 풍경화로서의 접근이 가능하게 된다. 이는 소비자들에게 정신적인 만족감과 더불어 제품의 프리미엄의 이미지를 각인시킨다. 두 번째 단계는 스토리이다. 기능을 디지털의 On/Off에 의거하여 나열 하기보다 기능과 기능사이의 문맥을 스토리로 연결함으로서 아날로그적인 접근이 가능하다. 이러한 스토리의 기준은 사용자의 경험에 기인하여 만들어지게 된다. 마지막으로 활용할 수 있는 단계는 컨텐츠이다. 이제는 한가지로 집중된 기능만으로는 사용자를 만족 시킬 수 없다. 사용자에게 인간적인 체온이 느껴지는 아날로그적인 컨텐츠를 제공함으로서 인터페이스 자체로 감동을 줄 수 있게 된다. 이와 같은 변화는 디지털제품의 궁극적인 목표가 사용자에게 있다는 것을 다시 한번 확인시켜준다. 이제는 똑똑하고 편리한 인터페이스를 넘어 사용자체가 감성적 만족감을 주는 매력적인 인터페이스로 진화 하고 있는 것이다.

• Journal of Chest Surgery
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• v.29 no.6
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• pp.621-625
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• 1996

"Middle lobe syndrome" which was described y Graham and associates at first is always caused by ex- ternal bronchial compression by Iymph nodes. Although the patients may not present any symptom, the most common presenting symptoms were cough, dyspnea, fever, hemoptysis, and chest pain. Diagnostic procedures includ chest X-ray bronchoscopy, brochography, chest CT, and the principal finding is the contracted middle lobe which is usually airless. We experienced fifteen cases of middle lobe syndrome from April 1990 to May 1995. Eleven patients were treated surgically. The surgical candidates for middle lobe syndrome are suspicious malignancy, fixed bronchiectasis, bronchostenosis, intractable to medical treatment, recurrent infection. Operations were right middle lobectomy (8), right middle and lower bilobectomy (2), right upper and middle bilobectomy (1). Postoperative histological findings were tuberculosis in six, chronic inflammation in three, malignancy in one, and focal hemorrhage in one. There were two cases of postoperat ve complications which were postoperative atelectasis and hepatopathy.patopathy.

• Journal of Environmental Science International
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• v.12 no.9
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• pp.967-976
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• 2003

Volatile organic compounds (VOCs) are present in essentially all natural and synthetic materials from petrol to flowers. In this study, indoor and outdoor VOCs concentrations of houses, offices and internet-cafes were measured and compared simultaneously with personal exposures of each 50 participants in Asan and Seoul, respectively. Also, factors that influence personal VOCs exposure were statistically analyzed using questionnaires in relation to house characteristics, time activities, and health effects. All VOCs concentrations were measured by OVM passive samplers (3M) and analyzed with GC/MS. Target pollutants among VOCs were Toluene, o-Xylene, m/p-Xylene, Ethylbenzene, MIBK, n-Octane, Styrene, Trichloroethylene, and 1,2-Dichlorobenzene. Indoor and outdoor VOCs concentrations measured in Seoul were significantly higher than those in Asan except Ethylbenzene. Residential indoor/outdoor (I/O) ratios for all target compounds ranged from 0.94 to 1.51 and I/O ratios of Asan were a little higher than those of Seoul. Relationship between personal VOCs exposure, and indoor and outdoor VOCs concentrations suggested that time-activity pattern could affect the high exposure to air pollutant. Factors that influence indoor VOCs level and personal exposure with regard to house characteristics in houses were building age, inside smoking and house type. In addition insecticide and cosmetics interestingly affected the VOCs personal exposure. Higher exposure to VOCs might be caused to be exciting increase and memory reduction, considering the relationship between measured VOCs concentrations and questionnaire (p<0.05).