• 한국농공학회지
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• 제18권1호
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• pp.4079-4086
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• 1976

In many reservoir projects, economic considerations will necessitate a design utilizing surcharge. Determination of the most economical combination of surcharge and spillway capacity for a given spillway crest level will require flood routing studies and economic studies of the dam-reservoir-spillway combinations. Many methods of actual flood routing have been devised, each of them with its advantages and disadvantages. Some of these methods are listed below: (1) Arithmetical trial-and-error method. (2) Modified Puls' method (3) Cheng's graphical method (4) Horton's arithmetical method (5) Ekadahl's arithmetical method (6) Digital computer programming. For the purpose of preliminary design and cost estimating of dams and spillways, it is often required to estimate, for a given design flood and spillway crest level. the approximate values of two among the three characteristics of the spillway spillway length, maximum discharge and surcharge depth at maximum discharge, when one of these quantities is given. As is well known, the outflow hydrograph for an ungated overflow spillway assumes the form of a wave-shaped curve with a minimum point for Q=o At zero time and a maximum point for Q=Qmax at its intersection with the falling leg of the inflow hydrograph (see Fig. 4) The shaded area between the inflow and outflow hydrographs represents at the approximate scale the temporary retention Vt. In line with the remarks, draw by free hand the assumed outflow hydrograph with its maximum point for the given Qmax (see Fig. 4) and by planimetration find Vt. From the reservoir capacity curve (Fig. 3) find Vs for the given spillway crest level and make V=Vs+Vt. From the above curve find surcharge water elevation for V and surcharge depth Hmax over spillway crest. From the discharge formula compute {{{{L= { Q} over { { CH}^{3/2 } } }}}} The methed provides a means for a quick and fairly accurate estimation of spillway capacity.

• 한국농공학회지
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• 제18권2호
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• pp.4116-4120
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• 1976

With the use of many rivers increased nearly to the capacity, the need for information concerning daily quantities of water and the total annual or seasonal runoff has became increased. A systematic record of the flow of a river is commonly made in terms of the mean daily discharge Since. a single observation of stage is converted into discharge by means of rating curve, it is essential that the stage discharge relations shall be accurately established. All rating curves have the looping effect due chiefly to channel storage and variation in surface slope. Loop rating curves are most characteristic on streams with somewhat flatter gradients and more constricted channels. The great majority of gauge readings are taken by unskilled observers once a day without any indication of whether the stage is rising or falling. Therefore, normal rating curves shall show one discharge for one gauge height, regardless of falling or rising stage. The above reasons call for the correction of the discharge measurements taken on either side of flood waves to the theoretical steady-state condition. The correction of the discharge measurement is to consider channel storage and variation in surface slope. (1) Channel storage As the surface elevation of a river rises, water is temporarily stored in the river channel. There fore, the actual discharge at the control section can be attained by substracting the rate of change of storage from the measured discharge. (2) Variation in surface slope From the Manning equation, the steady state discharge Q in a channel of given roughness and cross-section, is given as {{{{Q PROPTO SQRT { 1} }}}} When the slope is not equal, the actual discharge will be {{{{ { Q}_{r CDOT f } PROPTO SQRT { 1 +- TRIANGLE I} CDOT TRIANGLE I }}}} may be expressed in the form of {{{{ TRIANGLE I= { dh/dt} over {c } }}}} and the celerity is approximately equal to 1.3 times the mean watrr velocity. Therefore, The steady-state discharge can be estimated from the following equation. {{{{Q= { { Q}_{r CDOT f } } over { SQRT { (1 +- { A CDOT dh/dt} over {1.3 { Q}_{r CDOT f }I } )} } }}}} If a sufficient number of observations are available, an alternative procedure can be applied. A rating curve may be drawn as a median line through the uncorrected values. The values of {{{{ { 1} over {cI } }}}} can be yielded from the measured quantities of Qr$.$f and dh/dt by use of Eq. (7) and (8). From the 1/cI v. stage relationship, new vlues of 1/cI are obtained and inserted in Eq. (7) and (8) to yield the steady-state discharge Q. The new values of Q are then plotted against stage as the corrected steadystate curve.

• 호남수학학술지
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• 제36권1호
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• pp.67-83
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• 2014

The notion of rectifying curve in the Euclidean space is introduced by Chen as a curve whose position vector always lies in its rectifying plane spanned by the tangent and the binormal vector field t and $n_2$ of the curve, [1]. In this study, we have obtained some characterizations of semi-real spatial quaternionic rectifying curves in $\mathbb{R}^3_1$. Moreover, by the aid of these characterizations, we have investigated semi real quaternionic rectifying curves in semi-quaternionic space $\mathbb{Q}_v$.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.645-650
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• 2000

this paper deals with HVDC Light(High Voltage Direct Current) system using space vector PWM(SVPWM) method. Because the system of this paper has d-q control scheme for HVDC Light system. HVDC Light system represented in this paper is capable of controlling active and reactive power independently. For this system. V-I curve and control methods are proposed. Also this paper describes the design of a digital system for applications in power converters such as those that would be used in the next generation of HVDC system. Finally HVDC system is implemented using DSP TMS320C31

• 대한수학회논문집
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• 제27권3호
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• pp.497-503
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• 2012

In this paper, we study elliptic curves E over $\mathbb{Q}$ such that the 3-torsion subgroup E[3] is split as ${\mu}_3{\oplus}\mathbb{Z}/3{\mathbb{Z}}$. For a non-zero intege $m$, let $C_m$ denote the curve $x^3+y^3=m$. We consider the relation between the set of integral points of $C_m$ and the elliptic curves E with $E[3]{\simeq}{\mu}_3{\oplus}\mathbb{Z}/3{\mathbb{Z}}$.

• 한국산림과학회지
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• 제83권2호
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• pp.164-174
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• 1994

장기간의 수분 및 양료 stress를 받는 다섯 가지 주요 수종의 생리적인 대사 반응을 알아보기 위하여 상이한 토양수분 및 양료 조건의 pot에서 기른 실생묘의 시기적인 생육, 엽록소 함량 및 수분특성의 변화를 조사하였다. 이를 위해 상수리나무, 굴참나무, 신갈나무, 졸참나무 및 물푸레나무 실생묘를 내경 16cm, 깊이 16cm의 프라스틱 용기에 번식시켰다. 이들 묘목은 5월~9월까지 비닐 온실 내에서 건, 습 두가지 토양수분 조건 및 N+P+K 시비, 무시비의 두가지 시비 조건으로 조합 처리하였다. 환경 stress에 대한 반응을 분석하기 위해 5월, 7월, 9월에 묘고, 근원경, 엽록소 함량, P-V curve 모수들을 반복하여 측정했다. 수분 및 양료 부족에 따른 환경 stress는 묘목의 생육에 있어 수종, 생육시기 및 묘고와 근원경 간에 각기 다른 영향을 미쳤다. 상수리나무의 생육은 stress에 보다 예민하게 반응하여 감퇴되었지만 신갈나무는 나머지 수종에 비해 stress에 의한 생육부진 영향이 적었다. 엽록소의 함량은 생육기간 중 일반적으로 물푸레나무에 비해 참나무류에서 더 높은 값을 보였다. 엽록소 중 chlorophyll a의 함량은 0.14~1.96mg/g dry wt., chlorophyll b는 0.16~1.79mg/g dry wt. 내에서 생육기간 중 수종 및 처리 별로 변화했다. 그러나 엽록소 함량은 지속적인 환경 stress와 잎의 노화에 따라 점차 감소되었다. 최대포수상태와 위조점에서의 osmotic potential(${\Psi}{{\pi}o}$, (${\Psi}{{\pi}p}$)은 일부 예외는 있지만 각각 5월의 -7.0~-12.4bars에서 9월의 -10.2~-17.5bars로 3~5bars까지, 또한 5월의 -7.6~-14.2bars에서 9월의 -12.9~-20.4bars로 5~6bars까지 시간이 지나면서 감소했다. ${\Psi}{{\pi}p}$의 값은 일반적으로 5월 및 7월에 물푸레나무에서 높았으나 9월에는 졸참나무에서 높은 값을 보였다. 위조점에서의 상대수분함량 (RWCp)은 일반적으로 물푸레나무에서 높았지만 그 값의 시기적인 변화는 수종이나 처리 조건에 따라 상당한 차이를 보였다.

• Journal of Astronomy and Space Sciences
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• 제12권1호
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• pp.1-13
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• 1995

We carried out photometric and spectroscopic observatious of the blue compact dwarf galaxy Haro 6 in the Virgo Cluster of Galaxies. The long-slit spectroscopy was employed at three position angles, $\Phi$=$0^{\circ}$, $\Phi$=$30^{\circ}$, and $\Phi$=$120^{\circ}$with CCD camera mounted on the Cassegrain Spectrograph. Based on the mean intrinsic axial ratio < $q_0$ >=0.3, we derived inclination I of the system as $44^{\circ}$using our composite V-band CCD image. Careful analysis on the velocity field of the system shows an asymptotically fiat rotation curve with the maximum rotational velocity $V(r)_{max}$ reaches about 12km/sec. The calculation of the dynamical mass of Haro 6 with a simple mass model is briefly discussed with emphasis on the mass to luminosity ratio. From the IRAS Point Source Cataloque, we derived dust-to-gas ratio which indicates relatively low dust content, thus tempting us to conjecture the youth of the system.

• 대한전기학회논문지
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• 제45권4호
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• pp.501-510
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• 1996

The gas-turbine generator of Seo-Incheon combined-cycle plant was tested for derivation of a model for dynamic analysis. Load rejection and AVR step test was performed to get the dynamic response of generator. The parameters of generator/control system model were determined by these measured data. No-load saturation test was performed for the saturation characteristics of the generator under steady state. V-curve test was also performed so as to find exact generator parameters. Q-axis parameters of generator was derived by measuring power angle. AVR and governor constants have been tuned by their oscillatory period and setting time characteristics. The derived parameters of generator control system is verified by one-machine infinite bus system simulation. (author). 7 refs., 20 figs., 5 tabs.

• 대한화학회지
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• 제36권5호
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• pp.674-678
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• 1992

전기저항이 큰(묽은) 용액에서도 금속전극의 이중층 전기용량을 전위와 시간의 변화에 따라 연속적으로 정확신속하게 측정할 수 있는 간단한 기기를 설계제작하였다. 주사전위에 작은 진폭의 삼각파를 겹칠 때 정전용량의 응답으로 주어지는 구형파를 관찰하면서 용액의 비보상 저항을 보정하여 평평한 부분을 얻고 이부위의 진폭을 샘플-홀드 회로로 채취하여 기록한다. 샘플링 위치와 기간의 조절가능 기능과 저잡음 대책을 마련하여 삼각파의 진폭을 7mV까지 낮출 수가 있어 페러데이 임피던스 영향을 줄일 수가 있었다. 몇가지 경우에 대한 성능 실험을 통해 응용성과 한계를 고찰하였다.

• 생약학회지
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• 제49권1호
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• pp.70-75
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• 2018

Acer tegmentosum Maxim (ATM) has been used to treat hepatic disorders in traditional oriental medicine. However, there is little information about phytochemical constituents for quality control of ATM. In this study, we developed and established a simultaneous analytical method of the 10 marker compounds (three coumarins, 3 flavonoids, 1 lignan, 3 phenolics) in ATM using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). Chromatographic separation of ten target analytes was achieved with a Waters Acquity UPLC BEH $C_{18}$ analytical column ($2.1{\times}100mm$, $1.7{\mu}m$), using a mobile phase of 0.1% (v/v) formic acid in water and acetonitrile with gradient elution. Identifications and quantitation of all analytes were performed using a Q-Exactive UPLC-MS/MS system. Correlation coefficients of the calibration curve for all analytes were ${\geq}0.9986$. The values of limits of detection and quantification of all analytes were 0.5-10.0 and 5.0-50.0 ng/mL, respectively. The established UPLC-MS/MS method successfully identified all target analytes in ATM, and the phytochemicals were 0.01-67.98 mg/g in its lyophilized water extract.