• Nuclear Engineering and Technology
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• 제33권1호
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• pp.12-24
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• 2001

The post-LOCA long term cooling (LTC) performance of the Korean Standard Nuclear Power Plant (KSNPP) is analyzed for both small break loss-of-coolant accidents (LOCA) and large break LOCA at cold leg. The RELAP5/MOD3.2.2 beta code is used to calculate the LTC sequences based on the LTC plan of the Korean Standard Nuclear Power Plants (KSNPP). A standard input model is developed such that LOCA and the followed LTC sequence can be calculated in a single run for both small break LOCA and large break LOCA. A spectrum of small break LOCA ranging from \ulcorner.02 to 0.5 k2 of break area and a double-ended guillotine break are analyzed. Through the code calculations, the thermal-hydraulic behavior and the boron behavior are evaluated and the effect of the important action including the safety injection tank (SIT isolation and the simultaneous injection in LTC procedure is investigated. As a result, it is found that the sufficient margin is available in avoiding the boron precipitation in the core. It is also found that a further specific condition for the SIT isolation action need to be setup and it is recommended that the early initiation of the simultaneous injection be taken for larger break LTC sequences.

• JSTS:Journal of Semiconductor Technology and Science
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• 제2권1호
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• pp.30-40
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• 2002

A 2.45GHz double-balanced modified Gilbert-type CMOS up-conversion mixer design is introduced, where the PMOS current-reuse bleeding technique is demonstrated to be efficient in improving conversion gain, linearity, and noise performance. An LO buffer is included in the mixer design to perform single-ended to differential conversion of the LO signal on chip. Simulation results of the design based on careful modeling of all active and passive components are examined to explain in detail about the characteristic improvement and degradation provided by the proposed design. Two kinds of chips were fabricated using a standard $0.35\mu\textrm$ CMOS process, one of which is the mixer chip without the LO buffer and the other is the one with it. The measured characteristics of the fabricated chips are quite excellent in terms of conversion gain, linearity, and noise, and they are in close match to the simulation results, which demonstrates the adequacy of the modeling approach based on the macro models for all the active and passive devices used in the design. Above all the benefits provided by the current-reuse bleeding technique, the improvement in noise performance seems most valuable.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.241-243
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• 2008

This research presented the new zero-current switching pulse width modulation SEPP(Single Ended Push-Full)high frequency inverter for solving the problem of the zero-current SEPP high frequency inverter circuit which is using widely in the practical application of an induction heating apparatus, the soft switching operation and power control are impossible when the lowest power supply in the zero-current switching pulse width modulation SEPP high frequency inverter. The inverter circuit which is attempted by on-off operation of a switch has the reduction effect of the power loss due to a soft switching and a high frequency switching. And it confirmed that the power regulation is possible continuously from 0.25[kW] until 2.84[kW] in the case the duty rate(D) changes from 0.08 to 0.3 under zero-current switching operating by a dissymmetry pulse width modulating control and the power conversion efficiency comes true the efficiency of 95[%]. Due to the result above, the ZCS PWM SEPP high frequency inverter will be effective as sources of an induction heating apparatus.

• ETRI Journal
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• 제30권4호
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• pp.526-534
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• 2008

This paper presents a fully integrated 0.13 ${\mu}m$ CMOS MB-OFDM UWB transmitter chain (mode 1). The proposed transmitter consists of a low-pass filter, a variable gain amplifier, a voltage-to-current converter, an I/Q up-mixer, a differential-to-single-ended converter, a driver amplifier, and a transmit/receive (T/R) switch. The proposed T/R switch shows an insertion loss of less than 1.5 dB and a Tx/Rx port isolation of more than 27 dB over a 3 GHz to 5 GHz frequency range. All RF/analog circuits have been designed to achieve high linearity and wide bandwidth. The proposed transmitter is implemented using IBM 0.13 ${\mu}m$ CMOS technology. The fabricated transmitter shows a -3 dB bandwidth of 550 MHz at each sub-band center frequency with gain flatness less than 1.5 dB. It also shows a power gain of 0.5 dB, a maximum output power level of 0 dBm, and output IP3 of +9.3 dBm. It consumes a total of 54 mA from a 1.5 V supply.

• Journal of Power Electronics
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• 제7권3호
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• pp.246-256
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• 2007

In this paper, a novel type auxiliary active edge resonant snubber assisted zero current soft switching pulse modulation Single-Ended Push Pull (SEPP) series load resonant inverter using IGBT power modules is proposed for cost effective consumer high-frequency induction heating (IH) appliances. Its operating principle in steady state is described by using each switching mode's equivalent operating circuits. The new multi resonant high-frequency inverter with series load resonance and edge resonance can regulate its high frequency output power under a condition of a constant frequency zero current soft switching (ZCS) commutation principle on the basis of the asymmetrical pulse width modulation (PWM) control scheme. Brand-new consumer IH products using the proposed ZCS-PWM series load resonant SEPP high-frequency inverter using IGBTs is evaluated and discussed as compared with conventional high-frequency inverters on the basis of experimental results. In order to extend ZCS operation ranges under a low power setting PWM as well as to improve efficiency, the high frequency pulse density modulation (PDM) strategy is demonstrated for high frequency multi-resonant inverters. Its practical effectiveness is substantially proved from an application point of view.

• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.569-575
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• 2014

A highly efficient class E power amplifier is demonstrated for application to wireless power transfer system. The amplifier is designed with an L-type matching at the output for harmonic rejection and output matching. The power loss and the effect of each component in the amplifier with the matching circuit are analyzed with the current ratio transmitted to the output load. Inductors with a quality factor of more than 120 are used in a dc feed and the matching circuit to improve transmission efficiency. The single-ended amplifier with 20 V supply voltage shows 7.7 W output power and 90.8% power added efficiency at 6.78 MHz. The wireless power transfer (WPT) system with the amplifier shows 5.4 W transmitted power and 82.3% overall efficiency. The analysis and measurements show that high-Q inductors are required for the amplifier design to realize highly efficient WPT system.

• 조명전기설비학회논문지
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• 제17권4호
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• pp.20-25
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• 2003

본 논문은 기존 전자식 안정기에 사용되던 Boost 컨버터 형태의 역률 개선 부분을 SEPIC 컨버터 형태를 갖는 역률 개선 방식으로 대치하여 특성을 확인한 논문이다. Boost 컨버터 형태를 갖는 역률 개선 방식의 출력 DC 전압은 일반적으로 400[V]이며, 최소 전압은 입력 전원의 실효값 이상이어야만 한다. 하지만 SEPIC 컨버터 구조를 이용하면, 역율 개선 효과뿐만 아니라, 입력 전원의 실효값 보다 작은 출력 DC 전압을 얻을 수 있다는 장점을 가지고 있다. 본 논문에서는 SEPIC 컨버터 구조를 갖는 역율 개선 방식과 링코어를 이용한 자려식 발진 방식을 적용한 전자식 안정기를 제작하였고, 낮은 출력 전압을 이용하여 소자의 용량과 크기를 감소시켰다.

• Architectural research
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• 제21권1호
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• pp.1-8
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• 2019

Social housing has a long history in Germany from the first still existing social housing ever, the "Fuggerei" in Augsburg (founded in 1521), over the last 100 years from the end of World War I to today's situation where the need in social housing has increased while the number of housing projects and the number of existing apartments in this program has decreased or ended. Socio-economic changes like demographic evolution, more single households, greater working abilities in bigger cities and an unforeseen highly increased number of migrants within Europe mostly but also from other countries led to the need of affordable housing for a growing number of people who are not able to care for their housing needs in their own responsibility. This is especially true for bigger cities, where the offer of affordable housing is nearly non-existing any more. The family Fugger, a trade and banking dynasty at their time, established a very modern housing concept, providing good and healthy living space for their workers. In 2018 now some trade companies, discounters (ALDI, LIDL, Norma) and IKEA announce to combine their interest in sales in the inner cities with the municipal interest of redensification of existing housing areas and conversion to ecological urban reconstructuring.

• Child Health Nursing Research
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• 제29권3호
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• pp.207-217
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• 2023

Purpose: This study aimed to examine pediatric hospital nurses' perceptions and performance of family-centered care. Methods: A descriptive study design was used. This study surveyed 162 nurses who worked at a single tertiary children's hospital in South Korea. The modified Family-Centered Care Scale was used to assess nurses' perceptions and performance of family-centered care. Barriers to the implementation of family-centered care were described in an open-ended format. Results: Pediatric hospital nurses had a higher score for perceptions (mean score=4.07) than for performance (mean score=3.77). The collaboration subscale had the lowest scores for both perceptions and performance. The perceptions of family-centered care differed significantly according to the nurses' clinical career in the pediatric unit and familiarity with family-centered care, while performance differed according to clinical career only. Perceptions and performance were positively correlated (r=.594, p<.001). Barriers to implementation included a shortage of nursing personnel, a lack of time, and the absence of a family-centered care system. Conclusion: To improve the performance of family-centered care, nurses' perceptions of family-centered care should be improved by offering education programs and active support, including sufficient staffing, and establishing systems within hospitals.

• 반도체공학회 논문지
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• 제2권3호
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• pp.6-12
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• 2024

본 논문에서는 130nm CMOS 공정을 이용하여 제작된 2.4GHz 차동 캐스코드 전력 증폭기에 대한 연구를 제시하고 있다. 이 전력증폭기는 무선 전력 전송 응용을 위해 설계되었으며, 단일 종단 출력을 위한 발룬 트랜스포머 설계로 구성된 두 개의 차동 스테이지를 갖추고 있다. 출력 단 뿐만 아닌 각 단 사이의 전력 매칭을 위해 발룬 트랜스포머를 활용하고 있으며, 온도 보상이 가능한 바이어스 회로를 추가하여 2.4GHz 주파수 대역에서 안정적인 바이어스 전압을 유지한다. 이를 통해 TT/40℃에서 출력 전력은 21.75 dBm 이고 전력부가효율은 40.9%를 달성한다.