• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.43-45
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• 2006

대부분의 컨버터들은 초기 기동시에 MOSFET 전류와 전압의 과도한 상승을 막아주기 위해서 Soft Start 기능을 갖고 있다. 하지만 제어기 내부의 지연시간이나 LEB(Leading Edge Blanking) 시간 등으로 인해 MOSFET은 무시할 수 없는 상당한 기간의 최소 턴온 시간(Minimum Turn-on Time)을 갖게 되고, 이로 인해 드레인 전류가 과도하게 상승하는 현상을 보이게 된다. 본 논문에서는 이런 현상이 발생할 수 있는 초기 기동이나 출력단 단락시에 과도한 드레인 전류의 상승을 막아주는 방법을 제시하고자 한다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.4 no.4
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• pp.13-18
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• 1967

Since all the poles of the open circuit voltage transfer function of the trigonometric, linear, passive RC circuits exist on the negative real axis of s-plane, its transient response to the unit step input is monotonic. This satisfies the necessary conditions for the applicability of Elmore's method which had been developed originally for the transient analysis of lumped circuit in computing the rise time and delay time of the trigonometric distributed RC circuits. This paper describes the computing method of rise and delay times of the trigonometric distributed RC circuit. The analysis shows that the transient response of this kind circuit depends only upon the time constant and distance angle $\theta$. As $\theta$ is increased, the rise and delay titles are increased non-linearly.

• Korean journal of food and cookery science
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• v.10 no.4
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• pp.394-404
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• 1994

본 실험은 1.5Kg 무게의 고기를 3가지 다른 내부온도(60$^{\circ}C$-rare, 70$^{\circ}C$-medium, 80$^{\circ}C$-well done)에 이르도록 3가지 다른 출력의 전자파(40%, 60%, 100%)로 조리시에 나타나는 고기의 조리조건(조리시간, 대기시간 및 대기시 상승온도)과 고거의 물리 화학적인 변화(수분, 단백질, 지방, vit $B_1$의 함량, 콜라겐의 용해도, 보수력, texture)를 관찰하였다. 각 처리구 간에 Kg당 조리시간은 유의적인 차이를 나타내었으나 대기시간은 유의적인 차이를 나타내지 않았다. 그러나 고기의 내부용도가 낮은 처리구일수록 긴 대기 시간이 요구되었다. 대기시 상승온도도 각 처리구 간에 유의적인 차이를 나타내지 않았으나 거의 모든 처리구에서 10도 이상의 상승온도가 관찰되었다. 고기의 내부온도가 상승할수록 조리시 중량손실도 증가되었고, 수분함량, 수분: 단백질의 비, 보수력, 비타민 $B_1$의 함량도 감소되었다. Texture를 측정한 항목들에서는 각 처리구간의 유의척인 차이를 나타내지 않았다. 콜라겐의 용해도는 각 처리구간에 유의적인 차이를 나타내지 않았으나 내부온도 60$^{\circ}C$와 70$^{\circ}C$ 처리구 사이의 용해도는 뚜렷한 증가가 관찰되었다.

• Ecology and Resilient Infrastructure
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• v.9 no.2
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• pp.113-123
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• 2022

The blood and physiological changes of common carp (Cyprinus carpio) and crucian carp (Carassius auratus) were analyzed when the water temperature was rapidly increased from 20℃ (control) to 26 and 32℃. The water temperature reached 26℃ and 32℃ within 6 hours from the water temperature of 20℃, and the control was maintained at 20℃ for the duration of the experiment. From each experimental group, blood was collected every 3, 12, 24 and 48 hours after the water temperature rise, and the red blood cell count, hemoglobin, hematocrit, Na⁺, K⁺, Cl^-, cortisol, glucose, aspartate amino transferase (AST) and alanine amino transferase (ALT) contents were analyzed. In the case of the crucian carp experimental group where the water temperature was raised to 32℃, the concentrations of plasma cortisol, glucose, AST and ALT increased 3 hours after the water temperature rise, and the concentrations did not decrease until 48 hours (P<0.05). Plasma cortisol, glucose, AST, and ALT in both C. carpio and C. auratus in the control group and the experimental group raised to 26℃ increased at 3 hours after the water temperature rise (P<0.05), and decreased to the value before the water temperature rise at 48 hours (P<0.05). The plasma Na⁺, K⁺ and Cl^- concentrations of C. carpio and C. auratus in the experimental group where the water temperature was raised to 32℃ were higher than in the 20 and 26℃ experimental groups. The blood reaction of all experimental groups including the control group showed a common trend in both C. carpio and C. auratus increasing up to 12 hours after the water temperature rise and then decreasing at 48 hours after the water temperature rise. The results derived from this study would be useful for investigating the physiological response of fish stress in future. In addition, as fish mortality has recently occurred frequently in rivers and lakes, it is judged that it can be used as basic data.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.127-127
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• 2009

고밀도 유도 결합 플라즈마와 함께 -1 kV의 높은 펄스 직류 바이어스를 이용한 플라즈마 공정 장치를 CFD-ACE+를 이용하여 시변 모델로 해석하였다. 수 kHz의 낮은 펄스주파수와 $5{\mu}s$의 빠른 펄스 상승 시간의 효과에 의한 플라즈마 특성을 모사한 결과 전자 온도의 상승과 그에 의한 플라즈마 가열은 펄스 상승 시간 보다 수 ${\mu}s$늦게 발생하였으며 쉬스의 팽창은 Ar 10 mTorr에서 약 20 mm정도이며 계산된 전자 온도는 최고 20 eV에 이른다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.5
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• pp.601-610
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• 2023

The comprehension of water-level behavior in rivers is essential for effective flood and river environmental management. The objective of this study is to propose a methodology that can be used by field engineers engaged in actual practice, to readily identify the characteristics of water-level behavior during flood events. To this end, a total of 45 historical water-level records from 2010 to 2022 year, which provide flood information for the flood vulnerable districts of the Han River, were obtained. A Water-level Rise Behavior Curve (WRBC) was developed and suggested to quantify the amount of water-level rise per unit time during flood. As a result, the water-level rises by more than 80% of the total rise within the first 6.2 hours, followed by a gradual rise. The time required to achieve a particular equilibrium varied depending on the area and runoff characteristics of the upstream. Furthermore, the study revealed that the WRBC provides a statistical representation of the water-level rise trend during floods, and can be effectively utilized for flood mitigation measures in waterfront spaces and irrigation facilities.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.11a
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• pp.59-62
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• 1999

1. 미스트를 장시간 분사시킬 경우 분사기간동안 온도강하는 분사량에 무관하게 일정하나 분사종료 후 온도상승은 분사량이 많으면 온도상승이 현저히 지연된다. 반면 증가된 습도는 장시간 유지되기 때문에 적정 분사량이 존재한다. 2. 시설하우스내 고온장애와 습도장애를 극복하고 보다 유리한 실내환경을 유지하기 위해서는 적정 미스트 분무량을 유지시켜야 하며 동시에 분무시간과 휴지시간을 충분히 고려해야만 한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.2
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• pp.63-68
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• 2005

This paper describes the characteristics of effective impulse ground impedance of deeply driven ground rods combined with grounding grid or counterpoises with needles. The potential rises of the test ground electrodes were measured as a function of the rise time of applied impulse currents and the effective impulse ground impedances were calculated The impulse ground impedances of deeply driven ground rods strongly depend on the rise time of impulse currents and significantly reduced by the connection of grounding grids in parallel.

• Korean Journal of Optics and Photonics
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• v.24 no.2
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• pp.58-63
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• 2013

A theoretical analysis of the impact of rise time of a Q-switch on the output pulse performance is carried out in an Ytterbium-doped actively Q-switched fiber laser. The finite difference time domain (FDTD) method is used to numerically simulate the Q-switched fiber laser. It is shown that stable Gaussian-like pulse shape can be generated when the Q-switch rise time is increased and pulse repetition rate is enlarged.

• Journal of the Korean Society for Railway
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• v.10 no.6
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• pp.645-649
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• 2007

Ground systems flow fault currents into the ground, and suppress Ground Potential Rise (GPR) by the current. In this paper, we designed and fabricated a surge impedance meter to analyze the ground impedance in wide frequency ranges. The meter consists of a surge generator, a high speed sample/hold (S/H) circuit and an associated electronics. The surge generator produces surge voltage up to 5kV in ranges of $50\sim500ns$. Field tests were carried out to evaluate the surge impedance meter at a driven-rod ground system. The results showed that surge impedance of ground systems should be measured by various fast surge waveforms, since the impedance increases as the rise time of applied voltage increases.