• 한국산업정보학회논문지
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• 제17권7호
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• pp.119-125
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• 2012

본 논문은 변전소 내에서 취득된 데이터만을 이용하여 전계통 전압안정도를 확보하기 위한 실시간 변전소내 OLTC(On-Load Tap Changer)와 S.S(Switched Shunt)와의 협조제어 알고리즘을 제안하고자 한다. 전압레벨을 일정한 값으로 유지시키기 위해서 동작하는 OLTC의 제어를 잘못하게 된다면 오히려 계통의 안정도(전압안정도) 를 해치는 결과를 나타낼 수 있다. 이 논문에서는 단일 변전소에서 취득된 데이터만으로 전체 시스템의 상태를 판단할 수 있는 Z-index를 이용하였다. Z-index를 이용하여 시스템을 normal 상태와 abnormal 상태로 구분하였고, 각 상태에 따른 협조제어 알고리즘을 제안하였다. 알고리즘 검증을 위해서 Hypersim과 matlab simulink를 이용하였다.

• 펄프종이기술
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• 제32권2호
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• pp.26-34
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• 2000

Understanding the nip geometry and heat transfer phenomena of soft nip calenders, which has been used in the production of newsprint and coated papers for many years, is very important since improper setting of soft nip calendering conditions causes deterioration of paper quality and productivity. In this study theoretical analysis on nip pressure and heat transfer phenomena in the nip of soft nip calenders has been made. The variables examined were calendering pressure, surface temperature of the heating roll, nip residence time and ingoing sheet moisture, By measuring nip widths and maximum nip pressure with Prescale film at a normal temperature, accurate line load has been obtained. With this line load, nip pressures at different temperature and nip widths were calculated. Results showed that as temperature increased, nip widths increased and nip pressures decreased. Equations derived for the heat conduction phenomena in soft nip calender nip were derived based on the semi-infinite plate and finite difference method and were used for the analysis of heat transfer within the nip. Temperature profiles in z-direction of paper within the nip were obtained. Finite difference method allowed more accurate analysis of the heat transfer in the calender nip. In this study newsprint and coated paper were considered as a single plate and two-layer plate consisted of sheet and coating layers, respectively. Heat trans-fer to paper increased as heated roll surface temperature and nip residence time were increased.

• Journal of Astronomy and Space Sciences
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• 제5권1호
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• pp.9-18
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• 1988

연세대학교 천문대에서 1983~1987 기간에 Be 성 $\gamma$ Cas을 총 31일 밤 광전측광관측을 하여 312개의 UBV관측점을 얻었다. 우리가 얻은 자료 중에서 비교적 관측시간이 길었던 5일분의 자료로, V, B-V, U-B광도 곡선을 만들었고, $\gamma$Case 의 일반적인 측광학적 특성을, V/R번화와 최근 IUE 인공위성관측에서 나타난 high velocity narrow component(hvnc)의 시기와 관련시켜 검토하였다. 또한, $\epsilon$ Per는 $H\beta$선의 모양(line, profile)이 심하게 변하는 이색적인 B형 별인데, 우리는 1984년에 IUE인공위성에서 관측한 이 별의 스펙트럼 image data 6개조를 분석하여 $H\beta$선에서와 같은 흡수선의 모양 변화가 UV영역의 SiIVsk CIV선에서도 일어나고 있는지를 비교검토한 결과, 이 6개 자료에서는 어떤 변화도 발견하지 못했다.

• Journal of Astronomy and Space Sciences
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• 제11권1호
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• pp.107-114
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• 1994

Zeta Aurigae형 쌍성의 항성풍인자들 즉, 질량손실율, 항성풍의 속도, stochastic velocity를 결정하는 방법을 제시하였다. 이들 인자덜을 최소자승법으로 보정하기 위하여 Baade(1989)의 컴퓨터코드를 개선하였다. 이 개선된 코드는 자동차보정법으로 반복계산하여 항성풍인자들을 수렴시키는 것이다. 개선된 코드를 32 Cyg에 대하여 IUE 인공위성이 관측한 Fe II 공명선에 적용하여 질량손실율 $2.18\times10^{-8}M_\odot/yr$, 항성풍의 속도 132.12km/s, stochastic velocty 39.82km/s를 구하였다.

• 대한기계학회논문집B
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• 제21권11호
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• pp.1393-1402
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• 1997

Characteristics of the lifted flame which is generated by issuing of the fuel through the miniature nozzle, d = 0.164 mm, are studied using the planar laser induced fluorescence technique. OH radical is excited on the $Q_{1}$(8) line of the $A^{2}$.SIGMA.$^{+.leq.X2}$ .PI.(1, 0) band transition (283.55 nm) and LIF signals are captured at the bands of (0, 0) and (1, 1) transition (306 ~ 326 nm) using the filters and ICCD camera. Hydroxyl radical (OH) profile for nozzle attached flame shows that OH radical populations at the flame sides and flame tip are larger than those at the base. But for the lifted flame (tribrachial flame) case, those are larger at the flame base than at the flame tip and flame sides. The OH radical is more dense near the center line of flame base at the blowing out. This fact proves the Chung and Lee's blowout theory-blowout occurs when the flame is anchored at the flame axis. axis.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.25-32
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• 2001

Doosan Construction & Engineering Co., Ltd is building a railway tunnel beneath the Soo-Young River connecting MinLak Station and Centum City Station, a section 230, subway line 2, Pusan City, Korea. When completed the tunnel will have a finished inner diameter of 6.5m(21.311) throughout its total length of 840m(420m = 0.52 miles, Two Single Track Tunnel : 420m＋420m). The ground profile of the face toward shield machine is composed of multi layers, silty clay, clayey gravel, soft rock etc. This research paper is to predict ground deformation and variation of stresses around tunnel using Hyperbolic model, and to reflect the works on the next shield tunneling project. And this research paper is analyzed data of measuring instrument (such as settlement gauge, inclinometer, Multiple extensometer, etc.) which is installed along tunnel line for safety of tunnel. For calculations, the finite difference Method is applied. Backfill grouting material is supposed to have instantly strength of 10kg/$\textrm{cm}^2$ above, although its strength is available after 24 hours passed.

• 구강회복응용과학지
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• 제18권4호
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• pp.313-320
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• 2002

The purpose of the present study was to evaluate the marginal discrepancy and topography of artificial crown on teeth extracted due to severe periodontal disease. Twenty specimens were invested into metamethylacrylate resin and cutted into vertical slices along with the long axis of tooth. The selected marginal discrepancy between the outer edge of the crown and the finishing line of abutment was examined by stereo- microscope(Olympus, PM-VSP-3, Japan) at magnification of up to 10, and the topography of finishing margin on crown was observed by stereomicroscopeat magnification of up to $70{\times}$. The results were as follows. (1) The mean marginal discrepancy between extracted tooth and artificial crown were $50.82{\mu}m$. (2) There was a considerable difference in the microstructure of finishing margins among specimens. Microscopic Structure on finishing margin showed indefinite line, poor fit (open, underextended and overextended), distorted margin, and surface roughness. This study suggested that there could be necessary to consider the response of periodontium to the emergence profile of natural tooth and precision of marginal geometry while establishing treatment planning for the reconsruction of the artificial crown.

• 한국전기전자재료학회논문지
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• 제11권10호
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• pp.796-803
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• 1998

Intrinsic and proximity gettering are popular processes to get higher cumulative production yield and usually adopt multi-step annealing and high energy ion implantation, respectively. In order to test the combined processed of these, high energy \ulcornerAs\ulcorner ion implantation and 2-step annealing process were adopted. After the ion implantation followed by 2-step annealing, the wafers were cleaved and etched with Wright etchant. The morphology of cross section on samples was inspected by FESEM. The concentration profile of As was measured by SRP. The location and type of secondary defects inspected by HRTEM were dependent on the 1st annealing temperatures. That is, a line of dislocation located at $1.5mutextrm{m}$ apart from the surface at $600^{\circ}C$ lst annealing was changed to some dislocation lines or loops nearby the surface at 100$0^{\circ}C$. The density of dislocation line was reduced but the size of the defects was enlarged as the temperature increased.

• 한국결정성장학회지
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• 제2권2호
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• pp.53-62
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• 1992

SOI구조 형성을 위항 대용융 재결정(ZMR) 공정에서 타원형의 반사경을 기울여 빔강도분포를 인위적으로 변화시켜 실리콘 박막을 재결정시켰다. 비대칭 선형가열 효과를 해석하기 위하여 전산모사를 행하여 응고계면 근처에서의 온도분포와 열구배 변화를 조사하였다. 상부집속열원의 경사각이 증가할수록 액상의 과냉도와 실리콘 박막내의 결함열 간격은 증가하였다. 주된 결함은 연속적인 아결정립계였고 결함밀도가 낮은 경우는 isolated threading dislocations만이 관찰되었다. 단면 TEM과 박막 XRD 분석결과 실리콘 박막은 (100) 집합조직을 갖는 단결정 박막으로 재결정되었음을 확인할 수 있었다.

• 천문학논총
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• 제30권2호
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• pp.269-270
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• 2015

We carried out near-IR photometric and optical spectroscopic observations of V582 Aur, which is a FU Orionis type object, to investigate any periodic and/or aperiodic variations. We obtained light curves on the scale of a night and a year, in J, H and Ks bands with KASINICS (KASI Near Infrared Camera System) attached to the BOAO (Bohyun-san Optical Astronomy Observatory) 1.8-m reflector in Youngcheon, South Korea and examined photometric variations on the two time scales. So far we have not found any periodic brightness variations on the scale of a night. On the other hand, we have found that there seems to be a periodic brightness variation with a period of approximately 45 days. In addition, high-resolution optical spectroscopic observations of V582 Aur were performed from February 2013 to May 2014 with the high-resolution echelle spectrograph BOES attached to the BOAO 1.8-m reflector. We analyzed several spectral lines to understand the physical state of V582 Aur. The P Cyg profiles are clearly shown in the $H{\alpha}$ line and Na I D line.