• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.1
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• pp.43-52
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• 1996

Nonreciprocal twin-toroid ferrite phase shifter is designed, fabricated, and tested. ABCD matrix method is used to design the phase shifter and to compute its optimum dimen- sions. Quarter-wave two-section impedance matching transformers are utilized in order to match the impedance of the empty guide to that of the ferrite-loaded guide. Driving circuit controls the current needed to drive the phase shifter. Measured insertion loss and VSWR characteristics within the operaring band(9.1GHz ~ 9.5GHz) are less than 1.2dB and 1.15, respectively. After temperature compensation technique is appied to the phase shifter, the measured phase error of the phase shifter is less than $\pm4$ between $-10^{\circ}C\;and\;+60^{\circ}C$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.1
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• pp.32-43
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• 1999

In this paper, the transformed QMSA to load a capacitor without limitation of the electric force on QMSA(Quarter-wavelength Microstrip Antenna) is designed. Bandwidth of the designed and manufactured antenna is 5.7% at the resonant frequency of 2.0 GHz and the resonant frequency and bandwidth versus change of any arbitrary feed point is observed. Since the size of wide slot width between the left and right parallel plate to load a capacitor is very wide bandwidth, will be suitable for very wide bandwidth communication. The radiation pattern characteristics of the designed antenna based on the dipole structure and the aperture structure analysis method. As calculation results, relative backward radation is - 5 dB.

• 한국벤처창업학회:학술대회논문집
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• 2018.04a
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• pp.115-121
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• 2018

창업교육에서 강조하는 창의성 역량은 사회에 필요한 융합형 인재 육성을 위해 반드시 필요한 부분이다. 하지만 이제까지 창업교육에 대한 효과성을 검증함에 있어서 창업분야에 대한 단편적인 효과중심으로 연구되었고 진로에 어떠한 영향을 미치는지에 대한 효과 연구는 매우 부족한 실정이다. 이에 본 연구에서는 선행연구와 차별적으로 대학의 창업교육을 통한 역량함양이 사회에 진출을 앞두고 있는 대학생의 진로준비와 행동에 어떤 영향을 미치는지에 대해 실증분석 검증하였다. 2016년 8월부터 설문조사를 실시하였고 지역별 창업교육을 수강한 대학생 393개의 표본을 실증분석에 활용하였다. 분석결과 창업교육을 통해 함양된 협업적의사소통능력, 창의적문제해결능력은 기업가정신과 자기효능감에 정(+)의 영향을 미쳤고, 기업가정신과 자기효능감은 진로준비행동에 정(+)의 유의미한 영향을 미쳤다. 또한 기업가정신, 자기효능감의 매개효과 검증에서 협업적 의사소통능력, 창의적 문제해결능력과 진로준비행동 사이에 정(+)의 영향을 미쳤지만 창업교육에 의한 창의성 역량들은 진로준비행동에는 직접적인 유의미한 영향이 없는 것으로 분석되었다. 이에 본 연구의 시사점은 대학의 창업교육의 효과 검증에서 창업교육의 양적인 확대보다는 기업가정신과 자기효능감을 고취 함양시킴으로써 진로준비행동에 긍정의 영향을 미친다는 시사점을 도출 할 수 있었다. 또한 대학 창업교육의 중요성 검증과 향후 다양한 효과에 대한 평가를 학생창업 영역 뿐만 아니라 다각도로 추가 연구가 필요하겠다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.6
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• pp.1269-1281
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• 1989

본 연구에서는 H를 고정하고 L을 변화시켜가며 내부의 유동구조가 어떻게 변하는가를 살펴보고, 특히 재부착이 일어나는 경우에는 급확대 부분만 존재하는 기존 실험결과와 비교분석하여 하류의 급축소부분이 전체 유동구조에 어떤 영향을 미치는가를 살펴보고자 한다. 실험에서 사용된 작동유체는 공기이며, 입구관 직경은 110mm, 급확대점과 급축소점사이의 연결부 직경은 220mm, 연결부의 길이는 L=300, 600 그리고 900mm의 3가지를 선택하였으며 기준속도는 입구관의 중심속도로 9.71 m/s이다. 입구직경(110mm)을 기준으로 한 Reynolds 수는 $R_{e}$=73,000 이고 입구관반경과 연결부반경의 차이인 계단높이(H=55mm)를 기준으로 하면 $R_{e=36}$ ,500이다. 연결부 의 급확대부분에서 입구관반경을 기준으로 한 반경확대비는 2이고 급축소부분의 반경 축소비는 1/2이다. 측정항목은 유동방향의 벽면압력분포, 유동방향의 평균속도분포 및 난류강도 등이며, L=900mm인 경우는 반경방향과 원주방향의 난류강도, Reynolds 전단응력도 측정되었다.

• The Mathematical Education
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• v.50 no.1
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• pp.41-59
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• 2011

Given the importance of algebra in the early grades, this paper analyzed the contents of whole numbers and their operations from the perspectives of generalized arithmetic. In particular, the focus of analysis was given to the properties of 0 and 1, those of operations such as commutativity, associativity, and distributivity, and the relations between operations. As such, this paper analyzed in detail how such properties and relations were introduced and expanded across different grades. It is expected that many issues in this paper will serve basic information to develop instructional materials in a way to fostering students' algebraic thinking in the elementary grades.

• Journal of Life Science
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• v.13 no.5
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• pp.740-745
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• 2003

The vegetation of Mt. Geum in Namhae-gun Gyeongsangnam-do was investigated by the methodology of the ZM school, from February, 2000 to May, 2002. An actural vegetation map and vegetation table were constructed to understand the distribution of plant community in this area. The vegetation in this study area was classified into 10 communities (Pinus. densiflora, P. thunbergii, Quercus acutissima, Q. serrata, Q. variablis, Q. mongolica, Styrax ja-ponica, Corylopsis coreana, Zelkova serrata and Carpinus tschonoskii) and 1 afforestation (Chamaecyparis obtusa). According to the actual vegetation map, P. thunbergii forest, Q. serrata forest and Q. mongolica forest were found at the southern slope, northern slope and the center region of Mt. Geum, respectively. The forest of P. thunbergii was widely distributed in this area.

• Fire Science and Engineering
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• v.24 no.6
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• pp.34-44
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• 2010

This research paper surveyed the awareness of general administrative officials who oversee the disaster management and firefighting officials who take part in emergency rescue work in local governments on disaster response exercises. The result of the survey showed that both officials acknowledged the need of the equipment used in disaster response exercises, securing the budgets for exercises, establishing a network among related institutions, reflecting actual conditions and local characteristics to the exercises, reflecting the result of exercise evaluations to the disaster response manual and next exercises, and securing a command communication system required for exercises.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.3
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• pp.92-100
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• 2005

An optimal fuel manifold is suggested to improve the cooling performance of an injector face plate. The cooling performance at the center area of the injector face plate is to be augmented while the spatial injection uniformity is maintained. The comparison of the cooling performance of f candidates gives the conclusion that the dividing plate from 2-3 injector .ow to 9-10 injector. row is an optimal. The maximum face plate temperature decreases by 27$\%$ while the injection uniformity is close to that of the original design. The pressure drop in the fuel manifold of the optimal design is also same as the original design.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.1
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• pp.65-78
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• 2010

DARPA carries out several R&D programs for hypersonic vehicles to maintain the U.S. military superiority in air and space. Falcon program is the core of the DARPA's activitiy for the hypersonics including the long-term step-by-step approach from HTV-1, HTV-2, HTV-3X to HCV. Hypersonic Turbo-Based Combined Cycle (TBCC) engine technologies research and development programs, HiSTED, FaCET and Vulcan, are also the parts of their activities. Present article presents the summarized review on the backgrounds, technologies and relationships of those programs.

• Journal of the Korean Chemical Society
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• v.22 no.6
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• pp.380-385
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• 1978

Adsorption isotherms of o-xylene on Spheron 6, a graphitized carbon black, are obtained at various temperatures using a quartz beam microbalance. BET plots are made to estimate the molecular area of o-xylene from these isotherms. On Spheron 6, the molecular area of o-xylene (m.p $-25^{\circ}C$) remains constant until the temperature is increased up to $-15^{\circ}C$, but increases abruptly between $-15^{\circ}C$ and $-14^{\circ}C$, and then again remains constant thereafter. These results are interpreted as implying that the adsorbed o-xylene molecules are flatly localized on Spheron 6 with compact packing below $-15^{\circ}C$ while they gain a rotational degree of freedom around the benzene ring at the higher temperature.