• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.12
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• pp.700-708
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• 2004

Flux-reversal machine (FRM) is a new doubly-salient stator-permanent magnet (PM) machine with flux linkage reversal in the stator concentrated windings. It can operate in both motoring and generating modes. In this paper, a novel design technique to improve the performance of FRM is proposed. Proposed techniques have a new stator winding and a magnet arrangement method. The stator and rotor shape with a concave type and a flux barrier are also proposed. According to the experimental results, it is shown that the proposed FRM have an improved performance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.58-64
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• 2016

In this paper, the design of rotor shape was performed for improvement of start-up characteristics and efficiency in single-phase LSPM. In order to improve the start-up characteristics, shape of rotor aluminium cage bar was changed. Through arrangement of permanent magnets and installation of flux barriers, it was performed torque ripple reduction and efficiency improvement. Cogging torque and back-EMF is calculated by the no-load analysis, start-up time is calculated by the start-up state analysis, efficiency and torque ripple is calculated by steady state analysis. The characteristics of the motor were calculated through FEM.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.1
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• pp.92-97
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• 2008

In this Paper, we present a scaling theory for dual material surrounding gate (DMSGTs) MOSFETs, which gives a guidance for the device design and maintaining a precise subthreshold factor for given device parameters. By studying the subthreshold conducting phenomenon of DMSGTs, the effective conductive path effect (ECPE) is employed to acquire the natural length to guide the design. With ECPE, the minimum channel potential is used to monitor the subthreshold behavior. The effect of ECPE on scaling factor significantly improves the subthreshold swing compared to conventional scaling rule. This proposed model offers the basic designing guidance for dual material surrounding gate MOSFETs.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11b
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• pp.225-235
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• 2005

This paper outlined the status of the development of Korean Reference Disposal (KRS­1) system for high-level radioactive wastes. The repository concept was based on the engineering barrier system which KAERI has developed through a long-term research and development program. The design requirements were prepared for the conceptual design of the repository. The amount of PWR and CANDU spent fuels were projected with the current nuclear power plan. The disposal rates of PWR and CANDU spent fuels were analyzed. The reference geologic characteristics including classification of fracture zones were set for the KRS. The disposal concepts and the layout of the repository were described.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.64-66
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• 2004

Several techniques have been adopted in motor design of interior permanent magnet (IPM) type brushless DC (BLDC) motor to minimize cogging torque. IPM type motor has better ability in the centralization of flux than surface-mounted permanent magnet (SPM) type BLDC motor. So, the structure of IPM type BLDC motor has high saliency ratios that produce additional torque. However, this structure has a significant cogging torque that generates both vibration and noise. This paper describes new technique of the flux barriers design for reduction of cogging torque of IPM type BLDC motor. To reduce the cogging torque, flux barriers are applied in the rotor. Changing the number of barrier, the cogging torque is analyzed by finite clement method(FEM).

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.221-224
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• 2005

In order to traffic safety during winter season, snowfall and cold area has been spread the deicing chemicals, and the spraying amount is increasing every year. Use of deicing chemicals has been and will continue to be a major part of highway snow and ice control methods. Chloride-containing chemicals such as calcium chloride or rock salt are main deicers for the road. Extensive use of chloride deicers is, however, the source of substantial cost penalties due to their corrosive action and acceleration to deterioration concrete structures. Deterioration due to de-icer salt occurs in practice in concrete pavement, dike, barrier and similar structure. This paper reports the results of effect of de-icer salt on durability of concrete structure in winter. To protect concrete structure from damage by de-icer salt in winter, the exposure test was performed using three methods such as increase in design strength upto 35MPa application of granulated blast furnace slag powder, and concrete sealer. Of these, the method of increase in design strength upto 35MPa showed better durability for deterioration by de-icer salt.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.4
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• pp.629-633
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• 2015

영구자석 동기전동기가 전압과 전류 제한을 갖는 상태에서 고속으로 운전하기 위해서는 약 자속 제어를 수행해야 한다. 영구자석 동기전동기는 설계 방법에 따라서 정 토크 및 약 자속 영역에서의 출력 특성이 상이하게 된다. 본 논문에서는 약 자속 영역에서의 고 토크를 위한 IPMSM의 회전자 형상 설계를 수행하였다. 우선 마그네틱 토크와 릴럭턴스 토크의 관계에 따라서 약 자속 영역의 토크 향상을 위한 방법을 제안한다. 제안한 방법을 IPMSM의 회전자의 형상 설계를 통해 적용하였고, 유한요소 해석을 통해 기존 모델과 개선 모델의 특성을 비교 분석하여 제안한 방법의 타당성을 검증하였다.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.333-336
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• 2008

U-Channel Bridge is effective bridge type, because its edge beam performs role of barrier and enables to reduce additional dead loads. Nevertheless, there is possibility of bridge collapse under impact load due to car crash. Also, edge beam must have ability to induce safe driving and prevent falling accidents. Therefore, this study carries out analysis of behavior of edge beam and slab and evaluation of structural stability under impact loads, based on Korean Highway Bridge Design Specifications and AASHTO LRFD Bridge Design Specification. According to analysis result, the maximum stress of edge beam and slab satisfies specification of allowable stress.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.11
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• pp.970-978
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• 2003

This paper aims at suggesting design guidelines for a perimeter-less HVAC system that contributes energy savings. Perimeter-less HVAC system is one that relieves difficulties such as handling mixing loss, uneven radiative environment, and maintenance and repair. It prevents heat load gained through window and outdoor wall without modifying a previously equipped building skin system. In this paper, we conducted a large-scale model experiment to see how the push-pull air flow would handle indoor heat to obtain an optimized perimeter-less design, and then we plan to perform several kinds of CFD (computational fluid dynamics) cases through numerical simulation

• Progress in Superconductivity
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• v.3 no.1
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• pp.87-90
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• 2001

We designed a high temperature superconducting rapid single flux quantum(RSFQ) T flip-flop(TFF) circuit using Xic and WRspice. According to the optimized circuit parameters, we fabricated the TFF circuit with $Y_1$$Ba_2$Cu$_3$$O_{7-x}$(YBCO) interface-controlled Josephson junctions. The whole circuit was comprised of five epitaxial layers including YBCO ground plane. The interface-controlled Josephson junction was fabricated with natural junction barrier that was formed by interface-treatment process. In addition, we report second design for a new flip-flop without ground palne.e.