• 한국항공우주학회지
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• 제34권3호
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• pp.22-30
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• 2006

본 논문은 초소형 비행체 날개 주위의 공기흐름 조절을 위한 IPMC 작동기로 구동되는 ZNMF 펌프의 체계적인 설계 및 해석 기법을 소개한다. IPMC는 낮은 인가전압에서 큰 굽힘 변위를 발생시키며, 공기 중에서도 작동이 가능하고, 작은 크기로 손쉽게 제작할 수 있기 때문에 소형 펌프의 작동 막으로 매우 적합한 재료이다. 본 연구에서는 수치해석 기법을 이용하여 최대 작동 체적을 발생시키는 IPMC 작동 막의 최적 형상을 찾고, 이러한 최적형상에 기초하여 슬롯을 갖는 ZNMF 펌프를 설계하였다. 이후 초소형 비행체의 비행속도, 펌프 작동 막의 구동 주파수(~ 40 Hz), 슬롯을 통과하는 공기의 속도 등을 이용하여 무차원화 된 진동수와 모멘텀 계수를 구하였고, 설계된 ZNMF 펌프가 초소형 비행체 날개의 공기흐름 조절에 적용이 가능함을 보였다.

• 복식
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• 제56권6호
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• pp.45-57
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• 2006

The purpose of this research was to find the present condition on dementia patients clothes design including shapes, colors, construction and details in domestic. This research was for confirming the present problems, suggestions, and basic informations for development dementia patients clothes proto-types. The research methods and process were as follows; 1. The total 20 institutes (5 dementia specialty hospitals, 3 the senior hospitals and 11 nursing care centers) were researched during from June to August, 2005 by trained researchers who had experiences researches. 2. The total 30 nurses and care-givers were interviewed for find the present problems related the dementia patients clothes. 3. The total 39 suits for dementia patients clothes were collected and the design analysed such like shapes, colors, constructions and details by taking pictures and drawing flat works. 4. The present condition about the clothes and problems were found and suggest new ideas. The results were belows; 1 The most of institutes of domestic area had two piece type like general hospital patients' clothes for dementia patients clothes. It means there are no concerning now for old dementia patients. 2. The white colors were firstly used as fabric ground and secondly pale tone or pastel tone colors were used The blue and pink were used as pattern colors. The pattern colors were usually moderate tones. 3. The characteristics of constructions and details were round neckline, buttons, full-length sleeves, straight pants, ankle length pants. 4. New functional fabrics and designs for emotional satisfaction were demanded for dementia patients.

• 한국수의병리학회지
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• 제2권1호
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• pp.17-24
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• 1998

This is the first report of c-Jun protein expression and mRNA in a pancreatic islet in a nonobese diabetic(NOD) state mice. In this experiment NOD mice with insulin-dependent diabetes mellitus type I at age 16 weeks(n=7) just before death(n=4) were used. The control group consist of prediabetic NOD(8 weeks n=7) and ICR(8 weeks n=7 and 16 weeks n=7) mice. c-Jun positive cells in the pancreatic islet of NOD mice were localized in the same positions as a-glucagon producing cells. immunoreactivity was negative in the prediabetic NOD(8 weeks) and ICR(8 weeks and 16 weeks) mice. The number of c-Jun positive cells in mice with severe diabetic state just before death were significantly decreased when compared to NOD(16 weeks) mice. Expression of c-Jun in mRNA level was assessed by RT-PCR method. The levels of mRNA in NOD(16 weeks) mice group were elevated in total pancreatic tissues. The present results suggest that the induction of proto-oncogene protein may be of significance in assessing cell specific injury and may play a functional role between pancretic islet $\alpha$-cells and $\beta$-cells in the diabetic state.

• 천문학논총
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• 제32권3호
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• pp.381-405
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• 2017

We give a detailed description of the installation and operation of a double-station meteor detection system which formed part of a research & education project between Korea Astronomy Space Science Institute (KASI) and Daejeon Science Highschool. A similar system is currently not existing in South Korea. A total of six light-sensitive CCD cameras were installed with three cameras at SOAO and three cameras at BOAO observatory. A double-station observation of a meteor event enables the determination of the three-dimensional heliocentric orbit in space. This project was initiated in response to the Jinju fireball event in March 2014. The cameras were installed in October/November 2014. The two stations are identical in hardware as well as software. Each station employes sensitive "Watec-902H2" cameras in combination with relatively fast f/1.2 lenses. Various fields of views were used for measuring differences in detection rates of meteor events. We employed the SonotaCo UFO software suite for meteor detection and their subsequent analysis. The system setup as well as installation/operation experience is described and first results are presented. We also give a brief overview of historic as well as recent meteor (fall) detections in South Korea. For more information please consult http://meteor.kasi.re.kr.

• 생명과학회지
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• 제13권6호
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• pp.814-821
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• 2003

Heme 합성의 중간체이며 또한 광수용체로도 작용하는 protoporphyrin IX의 세포 내 농도 및 성장 배지에 존재하는 농도가 야생형 M. xanthus DK1622 균주로부터 측정되었다. Protoporphyrin IX의 세포 내 농도는 배양 시간이 경과함에 따라 계속 증가하여, 안정기에 최고치에 이르는 것으로 나타났다 안정기에 도달한 세포 내에는 6.4 picomoles/mg of protein의 protoporphrin IX이 존재하는 것으로 밝혀졌다. Protoporphyrin IX은 대수기 중간 시기부터 세포외로 분비가 시작되어, 안정기에 도달한 세포의 배양액에서는 세포의 단백질 대비하여 3.0 picomoles/mg of protein이 존재하는 것으로 측정되었다. 영양분의 고갈에 기인하여 형성된 포자에서도 protoporphyrin IX의 농도는 6.5 picomoles/mg of protein이 존재하는 것으로 관찰되었다. Succinylacetone을 $500\muM$ 농도로 성장 배지에 첨가하였을 경우에 protoporphyrin IX의 생산은 검출이 불가능할 정도로 방해를 받았으며, 세포성장이 저해되고 세포 성장은 정상의 절반 수준인 약 100 Klett unit에서 정지하는 것으로 나타났다. 하지만 포자의 형성은 succinylacetone의 첨가에 관계없이 89-100%의 생성율을 보였음으로 정상 농도의 protoporphyrin IX가 M. xanthus의 성장을 위해서는 중요하지만, 포자 형성 과정에 필수적인 것으로 보이지는 않는다. 안정기 세포에서 나타나는 photolysis 현상도 succinylacetone의 첨가 여부에 관계없이 유사한 수준으로 관찰되었다.

• 한국정보과학회논문지:시스템및이론
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• 제31권9호
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• pp.527-535
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• 2004

통합형 파일시스템이 차세대 파일시스템으로 주목받으면서 디지털 셋톱박스나 스트리밍 서버에서 멀티미디어 서비스의 QoS를 보장함과 동시에 텍스트 기반의 웹 문서나 그림 파일 등의 입출력 요청을 처리하는 것이 중요한 이슈로 부각되고 있다 그러나 하나의 파일서버에서 다양한 요구사항을 지닌 입출력들을 동시에 처리해야 하는 경우, 입출력 요청들의 디스크 탐색시간을 최소화하는 것을 목표로 하는 기존의 파일시스템에서는 멀티미디어 스트림의 QoS를 만족할 수가 없다. 본 논문에서는 이처럼 다양한 입출력 요청이 혼재하는 통합형 환경에서 멀티미디어 스트림의 QoS를 보장하는 파일시스템 개발에 대해 논의하고자 한다. 먼저 다양한 응용프로그램들의 입출력 요청을 QoS 요구사항에 따라 크게 두 가지-주기적인 요청, 산발적인 요청-로 구분하고, 입출력 요청 처리 수준에서 주기적인 요청에 높은 우선순위를 부여함으로써 멀티미디어 스트림의 QoS를 보장하도록 하였다. 또한, 이러한 메커니즘을 리눅스 운영체제에 구현하여 그 성능과 효과를 검증하였다.

• 전력전자학회논문지
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• 제6권5호
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• pp.438-445
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• 2001

본 논문은 메탈할라이드 램프용 고주파 변조방식 전자식 안정기에 관한 것이다. 제안한 안정기는 고주파 영역에서 동작되며 외부 점화기 없이 LC 공진회로를 이용하여 램프를 기동시키므로 매우 컴팩트하며, 통상의 저주파식 전자식 안정기에 비하여 효율이 좋다. 제안하는 안정기는 공명현상을 회피하기 위하여 20kHz에서 100kHz 범위 내에서 변조되는 주파수로 제어된다. 본 논문에서는 안정기 특성을 평가하기 위하여 새로운 실시간 공명현상 검출기를 제안하였다. 또한 직류단 전류 검출을 통한 무부하 검출 알고리즘 및 전력제어 알고리즘에 대하여 기술하였다. 그리고 제안하는 방법을 적용한 프로토타입의 150W 메탈할라이드 램프 안정기로 수행된 실험결과를 검토하였다.

• Smart Structures and Systems
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• 제7권4호
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• pp.303-317
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• 2011

A specially designed tendon, which is proposed by embedding an FBG sensor into the center king cable of a 7-wire strand tendon, was applied to monitor the prestress force and load transfer of ground anchor. A series of tensile tests and a model pullout test were performed to verify the feasibility of the proposed smart tendon as a measuring sensor of tension force and load transfer along the tendon. The smart tendon has proven to be very effective for monitoring prestress force and load transfer by measuring the strain change of the tendon at the free part and the fixed part of ground anchor, respectively. Two 11.5 m long proto-type ground anchors were made simply by replacing a tendon with the proposed smart tendon and prestress forces of each anchor were monitored during the loading-unloading step using both FBG sensor embedded in the smart tendon and the conventional load cell. By comparing the prestress forces measured by the smart tendon and load cell, it was found that the prestress force monitored from the FBG sensor located at the free part is comparable to that measured from the conventional load cell. Furthermore, the load transfer of prestressing force at the tendon-grout interface was clearly measured from the FBGs distributed along the fixed part. From these pullout tests, the proposed smart tendon is not only expected to be an alternative monitoring tool for measuring prestress force from the introducing stage to the long-term period for health monitoring of the ground anchor but also can be used to improve design practice through determining the economic fixed length by practically measuring the load transfer depth.

• 한국수학사학회지
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• 제32권4호
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• pp.159-173
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• 2019

In this paper, we examine the brief history of the ring of four almonds regarding Mesopotamian mathematics, and present reasons why the Omar Khayyam's triangle, a special right triangle in a ring of four almonds, was essential for artisans due to its unique pattern. We presume that the ring of four almonds originated from a point symmetry figure given two concentric squares used in the proto-Sumerian Jemdet Nasr period (approximately 3000 B.C.) and a square halfway between two given concentric squares used during the time of the Old Akkadian period (2340-2200 B.C.) and the Old Babylonian age (2000-1600 B.C.). Artisans tried to create a new intricate pattern as almonds and 6-pointed stars by subdividing right triangles in the pattern of the popular altered Old Akkadian square band at the time. Therefore, artisans needed the Omar Khayyam's triangle, whose hypotenuse equals the sum of the short side and the perpendicular to the hypotenuse. We presume that artisans asked mathematicians how to construct the Omar Khayyam's triangle at a meeting between artisans and mathematicians in Isfahan. The construction of Omar Khayyam's triangle requires solving an irreducible cubic polynomial. Omar Khayyam was the first to classify equations of integer polynomials of degree up to three and then proceeded to solve all types of cubic equations by means of intersections of conic sections. Omar Khayyam's triangle gave practical meaning to the type of cubic equation $x^3+bx=cx^2+a$. The work of Omar Khayyam was completed by Descartes in the 17th century.

• 천문학회보
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• 제44권1호
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• pp.37.2-37.2
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• 2019

Recent investigations of the double red clump in the color-magnitude diagram of the Milky Way bulge cast serious doubts on the structure and formation origin of the outer bulge. Unlike previous interpretation based on an X-shaped bulge, stellar evolution models and CN-band observations have suggested that this feature is another manifestation of the multiple stellar population phenomenon observed in globular clusters (GCs). This new scenario requires a significant fraction of the outer bulge stars with chemical patterns uniquely observed in GCs. Here we show from homogeneous high-quality spectroscopic data that the red giant branch stars in the outer bulge ($>5.5^{\circ}$ from the Galactic center) are clearly divided into two groups according to Na abundance in the [Na/Fe] - [Fe/H] plane. The Na-rich stars are also enhanced in Al, while the differences in O and Mg are not observed between the two Na groups. The population ratio and the Na and Al differences between the two groups are also comparable with those observed in metal-rich GCs. Since these chemical patterns and characteristics are only explained by stars originated in GCs, this is compelling evidence that the outer bulge was mostly assembled from disrupted proto-GCs in the early history of the Milky Way. We will also discuss the implications of this result on the formation of the early-type galaxies in general.