• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기설비전문위원
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• pp.107-109
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• 2005

Temperature distribution measured to estimate condition of an electrical apparatus is an absolute reference for the apparatus conditions and the difference between the reference temperature and the current one. Because a passive thermography without the external thermal stimulation shows the difference in surface temperature between the object and back ground, the results can apply only to the estimation or the monitoring for the condition of terminal loose and the overload pertaining to the rise in temperature. However, a thermal flow in the active thermography is differently generated by the structure and condition of the surface and subsurface. This paper presents the nondestructive testing using the behavior and deals with the results by heat injection and cooling to the apparatus. The buried discontinuity of subsurface could be detected by these techniques.

• Structural Engineering and Mechanics
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• 제18권4호
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• pp.517-539
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• 2004

Many types of passive control devices have been recognized as effective tools for improving the seismic resistance of structures. A lot of past research has been carried out to study the response of structures equipped with energy-absorbing devices by assuming that the behavior of the beam-column systems are linearly elastic. However, linear theory may not be adequate for beams and columns during severe earthquakes. This paper presents the results of research on the nonlinear responses of structures with and without added passive devices under earthquakes. A new material model based on the plasticity theory and the two-surface model for beams and columns under six components of forces is proposed to predict the nonlinear behavior of beam-column systems. And a new nonlinear beam element in consideration of shear deformation is developed to analyze the beams and columns of a structure. Numerical results reveal that linear assumption may not be appropriate for beams and columns under seismic loadings, especially for unexpectedly large earthquakes. Also, it may be necessary to adopt nonlinear beam elements in the analysis and design process to assure the safety of structures with or without the control of devices.

• Korean Journal of Acupuncture
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• 제24권4호
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• pp.151-162
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• 2007

Objectives : The purpose of this study was to examine the anti-allergic effect in vivo, and to observe single toxicity in mice of Armeniacae Semen herbal acupuncture solution (ASHA). Methods : We investigated anti DNP IgE-mediated passive cutaneous anaphylaxis in rodents and compound 48/80-induced active systemic anaphylatic shock in mice after treatment at both BL13 with ASHA of 25 ${\mu}{\ell}$(mice) or 50 ${\mu}{\ell}$(rats) 3 times for 5 days. To ascertain safety and toxicity of ASHA, we examined single toxicity test. In single test, three groups were treated with different dosages of ASHA (ASHA250, ASHA500 and ASHA1000) according to on Korean Food and Drug Administration, respectively. We observed attentively motality, abnormal clinical sign, body weight change, and organ weight of mice after ASHA treatment. Results : ASHA inhibited passive cutaneous anaphylaxis and active systemic anaphylatic shock by oral administration. During toxicity experiment period, there was no difference in body weight change, and organ weight among different dose groups. Death were not found in single test i.p. group. (ASHA250, ASHA500 and ASHA1000). Several individuals of single test i.p. group were observed yellow brown discharge around anus in early period after administration. Conclusions : These results indicate that ASHA have inhibition effects on passive cutaneous anaphylaxis and active systemic anaphylatic shock, and suggest that has some toxicity in high dosage.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2003년도 춘계학술발표회
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• pp.135-139
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• 2003

이 논문에서는 새로 개정된 2000 SOLAS 규정에 근거한 어업용 수동식 레이더 리프렉터(PRR-F) 개발에 관해서 기술했다. PRR-F의 목적은 어망이나 어장의 보호 장치로 사용하는 것이다. PRR-F는 가벼운 양철 재질의 코너 크로스터 묶음을 부유 스티로폼 안에 내장한 형태로 구성하였다. PRR-F를 전파흡수실에서 성능 실험한 결과, 레이더 반사된 신호의 크기가 개발 목적에 충분하였다.

• 조명전기설비학회논문지
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• 제27권11호
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• pp.27-36
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• 2013

Islanding in a gird connected inverter of wind power generation system may influence a bad effect on equipments or yield safety hazards on grid so it should be detected rapidly and exactly. A passive method to detect islanding is comparatively simpler than an active method but suffers from non detection zone (NDZ). On the other hand, the active method can significantly reduce NDZ by injecting a disturbance into inverter output. To improve the reliability of islanding detection, this paper proposes a hybrid anti-islanding detection method combining the conventional passive method as well as the active method based on novel harmonic injection method using fourier transform. The proposed scheme is fast to detect islanding when NDZ does not exist because it has the nature of passive method. Under NDZ, the active method can detect occurrence of islanding reliably. The effectiveness and validity of the proposed scheme is proved through comparative simulations.

• 대한기계학회논문집B
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• 제24권3호
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• pp.338-345
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• 2000

A model testing has been performed to investigate the flow characteristics of a vortex chamber, which plays a role of a flow switch and passively controls the discharge flow rate. This method of passive flow control is a matter of concern in the design of advanced nuclear reactor systems as an alternative to the active flow control to provide emergency water to the reactor core in case of postulated accidents like LOCA (Loss-Of-Coolant Accident). By changing the inflow direction in the vortex chamber and varying the flow resistance inside the chamber, the vortex chamber can control passively the injection flowrate. Fundamental characteristics such as discharge flow rate and pressure drop of the vortex chamber are measured, and its parametric effects on the performance of the vortex chamber are also systematically investigated.

• Nuclear Engineering and Technology
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• 제52권5호
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• pp.964-974
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• 2020

The small modular reactors (SMRs) of the integrated pressurized water reactor (IPWR) type have been widely developed owing to their enhanced safety features. The SMR-IPWR adopts passive residual heat removal system (PRHRS) to extract residual heat from the core. Because the PRHRS removes the residual heat using the latent heat of the water stored in the emergency cooldown tank, the PRHRS gradually loses its cooling capacity after the stored water is depleted. A quick restoration of the power supply is expected infeasible under station blackout accident condition, so an advanced PRHRS is needed to ensure an extended grace period. In this study, an advanced design is proposed to indirectly incorporate a dry air cooling tower to the PRHRS through an intermediate loop called indefinite PRHRS. The feasibility of the indefinite PRHRS was assessed through a long-term transient simulation using the MARS-KS code. The indefinite PRHRS is expected to remove the residual heat without depleting the stored water. The effect of the environmental temperature on the indefinite PRHRS was confirmed by parametric analysis using comparative simulations with different environmental temperatures.

• Ocean and Polar Research
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• 제42권4호
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• pp.293-301
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• 2020

Blades of tidal stream turbines have to sustain many different loads during operation in the underwater environment, so securing their structural safety is a key issue. In this study, we focused on periodic loads due to wave orbital motion and propose a load reduction method with a blade design. The flap of an airplane wing is a well-known structure designed to increase lift, and it can also change the load distribution on the wing through deflection. For this reason, we adopted a passive flap structure for the load reduction and investigated its effectiveness by an analytical method based on the blade element moment theory. Flap torsional stiffness required for the design of the passive flap can be obtained by calculating the flap moment based on the analytic method. Comparison between a flapped and a fixed blade showed the effect of the flap on load reduction in a high amplitude wave condition.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.2088-2095
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• 2023

The safety of nuclear installations is largely determined by the tightness of fuel elements cladding. As the Fukushima nuclear accident showed, the main task in case of loss of power supply is to ensure reliable removal of residual heat release from spent fuel pool (SFP) with irradiated fuel assemblies (IFAs). The paper presents the results of calculated-experimental studies and thermal-hydraulic modeling of temperature storage modes of IFAs in SFP. Experimental studies of SFP's temperature regime and calculated evaluation of residual heat removal due to the thermal conductivity of building structures surrounding the SFP were performed. To ensure the safe operation of research reactors, it's necessary to know the IFA's residual heat power (RHP) in the reactor and SFP, which is determined depending on the operating time of fuel assemblies (FAs) and the IFAs calculated holding time. The FAs operating time depends on the reactor energy output. The IFAs calculated holding time is determined by the fuel burnup, U-235 mass in the fuel, and reactor utilization factor. The IFAs fuel burnup was calculated using the MCU-PTR program. Also presented are the RHP's calculation results using some of the empirical dependencies. The concept of a passive heat removal system (PHRS) based on thermosyphon's operating principle was proposed.

• Toxicological Research
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• 제8권1호
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• pp.139-143
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• 1992

Antigenicity tests-ASA(Active Systemic Anaphylaxis), PSA(Passive Systemic Anaphylaxis), PCA(Passive Cutaneous Anaphylaxis)-of CP-2(Green cross Co). were performed according to the established regulations of National Institute of Safety Research. The results were as follows. 1. No specic clinical signs related anaphylaxis were observed, therefore, it was considered that CP-2 had not antigenicity in guinea pigs and rabbits. 2. No blue spots were observed on the back of guinea pig in the PCA test` CP-2 related IgE was not produced.