• 동력기계공학회지
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• 제13권6호
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• pp.102-109
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• 2009

A retarder, as a supplementary brake system that is not friction-based, is frequently used in heavy-duty vehicles generally to slow the vehicles down on inclines. The electric retarder mainly used in a heavy-duty bus is generally placed between the transmission and the axle. The rotor inside the retarder system is attached to the axle. The operation of the retarder within a driven vehicle generates reverse torque due to coast driving force on hypoid gears in the differential gear system. By the reverse torque, scoring or scuffing on the hypoid gear teeth may directly occur. The scoring may be generated due to excessive contact stresses on the tooth surface. In this study, tooth contact stresses and contact patterns were analysed in order to investigate on the tooth scoring phenomenon using a finite element analysis program T900 in which the Hertzian contact stress formula was taken. Backlash, wear and surface finish were considered in the finite element simulation on the scoring.

• 대한전기학회논문지
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• 제33권8호
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• pp.289-298
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• 1984

The single phase induction motor is recently requested to meet a broad speed control and smooth forward and reverse operation due to the multifarious usages. This paper deals with two phase operation of a two winding motor by reference current adaptive inverter which can supply the currents to satisfy the balanced oeration into the main and auxiliary winding through the entire operational region. According to the roposed system, the starting, forward and reverse and variable speed control of a two winding motor eliminated the capacitor from the capacitor-run motor is also possible. The formation and its principle of the reference current adaptive inverter and characteristic analysis of the motor fed by this apparatus are described in this paper. Excellent agreement with the measured results and calculated values by computer simulation is obtained.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1429-1433
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• 2004

Recently, a dangerous event occurred at the field industry and mechanical system. At developed by SUNGGOK corp. a R-L clutches of a small and high capacity serves safety device from a variety environment of mechanical system, it permits transmission of driving torque form input to output shaft in both directions of rotation, but restrains any feedback torque of the driven load from rotating the output shaft in either direction. This study was carried out to demonstrate through finite element methode and durability estimation for safety of the R-L clutches without sliding during the engagement process. As results, we organized about endurance test methode when applied rated torque.

• 한국통신학회논문지
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• 제23권5호
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• pp.1282-1290
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• 1998

In this paper, the physical layer design of IMT-2000 system being developed by SK Telecom is introuduced. The outband signaling scheme and the two-pilot scheme are adopted for multimedia service and inter-cell asynchronous mode respectively. In addition, the synchronous transmission scheme is proposed to reduce the interference in the reverse link. The algorithm and simulation results of 'two-pilot scheme' for inter-cell asynchronous mode and 'reverse synchronous control' for synchronous transmission are presented.

• 산업공학
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• 제12권4호
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• pp.602-616
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• 1999

Recently, due to the primary emphasis of environmental problem, the proper selection of the membrane systems necessary for waste water treatment has been one of the critical issues in the industrial sector. This paper shows how an Analytic Hierarchy Process (AHP) model can be used for assessing the performance of selected membrane systems: ultrafiltration, microfiltration, reverse osmosis, and electrodialysis essential for waste water treatments. The final results show that ultrafiltration is the most attractive membrane system to use in a water recycling system, followed by microfiltration, reverse osmosis and electrodialysis. This is consistent with the information that we found with respect to the elements that were taken into consideration. Sensitivity analysis is also provided here.

• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1384-1387
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• 2005

Hantavax(R) is one of the killed Hantavirus vaccines, and is commercially available in South Korea. This vaccine was developed by inactivation of virus isolated from infected suckling mouse brain with formalin. Although Hantavax(R) can induce neutralizing antibodies in vaccinees, the strength of this induction and the duration of the humoral immune response are controversial issues. In this study, we studied the native conformation of the killed vaccine by antigen-capture reverse transcriptase polymerase chain reaction with patient and vaccinee sera containing neutralizing antibodies against Hantavirus. The results showed that Hantavax(R) could bind HTNV patient and vaccinee sera like live virus, suggesting that the integrity of the viral epitope is maintained in Hantavax(R) and induces the protective antibodies, even though the virus was inactivated with formalin.

• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.461-467
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• 2007

Staphylococcus aureus strains are important foodborne pathogens that produce various toxins. To evaluate the risk of the enterotoxins, four S. aureus strains from kimbap and two clinical samples were isolated and identified, and their expression of the enterotoxin genes were analyzed using a reverse transcription real-time PCR. Various enterotoxin genes were detected, including sea, seg, seh, sei, sen, seo, and sem, where each isolate contained one or two. When the mRNA detection of the enterotoxin genes was analyzed using a reverse transcriptase PCR, various levels of expression were found depending on the species and enterotoxin gene. Therefore, it is reasonable to suggest that the poisoning risk of S. aureus can be effectively evaluated based on the gene expression at the mRNA level.

• 한국초전도ㆍ저온공학회논문지
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• 제17권3호
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• pp.41-46
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• 2015

Recently, the development of the HTS power cable is actively promoted. As the length of HTS power cable increases, there have been many efforts to develop large capacity cryocooler. Among the various cryocooler, the Brayton refrigerator is the most competitive for HTS power cable. The Brayton refrigerator is composed of recuperative heat exchangers, a compressor, and a cryogenic turbo expander. In these components, the cryogenic turbo expander is a part to decrease the temperature and it is the most significant component that is closely related with overall system efficiency. It rotates with high speed using a high-pressure helium or neon gas at cryogenic temperature. This paper describes the design of a 10 kW class Brayton refrigeration cycle and the cryogenic turbo expander. Flow and structural analysis are performed for the rotating impeller and nozzle to verify the efficiency and the design performance.

• 한국통신학회논문지
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• 제24권6A호
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• pp.845-854
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• 1999

DS/CDMA 방식의 역방향 링크 구조에 Peak-to-Average Ratio(PAR) 성능은 대역 확산 신호의 위상의 변화로 해석된다. 본 논문에서는 대역확산 신호의 위상 변화를 이용하여 PAR 특성을 해석하는 방법을 제안한다. 이러한 해석 방법을 토대로 기존의 방법을 분석하고, 몇 가지 PAR 성능 개선 방법의 예를 제시하였다. 또한 제시된 방법이 BER 성능에서도 기존의 방법과 큰 차이가 없음을 확인하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.391-392
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• 2008

A SPICE-based 3-dimensional circuit model of Light-Emitting Diode(LED) was modified include the reverse breakdown properties. The new model is found to be accurate to study the failure mechanisms of LEDs under electrostatic discharge (ESD) and electronic overstress (EOS). It was found that the permanent damages under heavy reverse stress is mainly due to the high electric field strength in P-GaN layer.