• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.2176-2181
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• 2011

This paper estimates the life cycle cost(LCC) of a propulsion control system using the maintenance information in the high speed train(KTX-1). Life cycle costing is one of the most effective approaches for the cost analysis of long-life systems such as the KTX-1. Until now, most life cycle cost of the system has been studied as a whole system viewpoint. But in case of railway industry, LCC studies are needed on the subsystem like a propulsion control system because subsystems are developed continuously localization. This paper proposes the life cycle cost model which fitted to estimate life cycle cost (LCC) using maintenance information manual. As a result, LCC on propulsion control system increased moderately expect for periodical time when major parts are replaced at the same time. Results will be reflected in the development of domestic products.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2132-2135
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• 2005

Cylindrical type air core pulse transformers capable of passing high voltage and energy pulse waveforms with high efficiency and low distortion require a much more delicate design balance of physical dimensions and electrical parameters than iron or ferrite core units. The structure of an air core high voltage pulse transformer is relatively simple, but considerable attention is needed to prevent breakdown between transformer windings. Since the thickness of the windings in spiral type is on the order of sub-millimeter, field enhancement at the edge of the windings is very high. It is, therefore, important to find proper electrical insulation Parameter to make the system compact. Several shapes of the winding are considered for air core pulse transformer development. In this paper, we are described design procedure, parameters measure and experiment results of air core type HV pulse transformer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.348-349
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• 2007

This paper describes the electrical characteristics of polycrystalline (poly) 3C-SiC thin film diodes, in which poly 3C-SiC thin films on n-type and p-type Si wafers, respectively, were deposited by APCVD using HMDS, Hz, and Ar gas at $1180^{\circ}C$ for 3 hr. The schottky diode with Au/poly 3C-SiC/Si(n-type) structure was fabricated. Its threshold voltage ($V_d$), breakdown voltage, thickness of depletion layer, and doping concentration ($N_D$) values were measured as 0.84 V, over 140 V, 61nm, and $2.7\;{\times}\;10^{19}\;cm^3$, respectively. The p-n junction diodes fabricated on the poly 3C-SiC/Si(p-type) were obtained like characteristics of single 3C-SiC p-n junction diodes. Therefore, poly 3C-SiC thin film diodes will be suitable microsensors in conjunction with Si fabrication technology.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.180-183
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• 2003

The monolayer of oxygen atoms sandwitched between the adjacent nanocrystalline silicon layers was formed by ultra high vacuum-chemical vapor deposition (UHV-CVD). This multi-layer Si-O structure forms a new type of superlattice, semiconductor-atomic superattice (SAS). According to the experimental results, high-resolution cross-sectional transmission electron microscopy (HRTEM) shows epitaxial system. Also, the current-voltage (I-V) measurement results show the stable and good insulating behavior with high breakdown voltage. It is apparent that the system may form an epitaxially grown insulating layer as possible replacement of silicon-on-insulator (SOI), a scheme investigated as future generation of high efficient and high density CMOS on SOI.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.9-12
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• 2004

In this paper, a new small sized Lateral Trench Electrode Power MOS was proposed. This new structure, called LTEMOS(Lateral Trench Electrode Power MOS), was based on the conventional lateral power MOS. But the entire electrodes of LTEMOS were placed in trench oxide. The forward blocking voltage of the proposed LTEMOS was improved by 1.5 times with that of the conventional lateral power MOS. The forward blocking voltage of LTEMOS was about 240 V. At the same size, an improvement of the forward blocking voltage of about 1.5 times relative to the conventional MOS was observed by using ISE-TCAD which was used for analyzing device's electrical characteristics. Because all of the electrodes of the proposed device were formed in each trench oxide, the electric field was crowded to trench oxide and punch-through breakdown was occurred, lately.

• Korean Journal of Materials Research
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• v.30 no.7
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• pp.333-337
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• 2020

Orthorhombic DyMnO₃ films are fabricated epitaxially on Nb-1.0 wt%-doped SrTiO₃ single crystal substrates using pulsed laser deposition technique. The structure of the deposited DyMnO₃ films is studied by X-ray diffraction, and the epitaxial relationship between the film and the substrate is determined. The electrical transport properties reveal the diodelike rectifying behaviors in the all-perovskite oxide junctions over a wide temperature range (100 ~ 340 K). The forward current is exponentially related to the forward bias voltage, and the extracted ideality factors show distinct transport mechanisms in high and low positive regions. The leakage current increases with increasing reverse bias voltage, and the breakdown voltage decreases with decrease temperature, a consequence of tunneling effects because the leakage current at low temperature is larger than that at high temperature. The determined built-in potentials are 0.37 V in the low bias region, and 0.11 V in the high bias region, respectively. The results show the importance of temperature and applied bias in determining the electrical transport characteristics of all-perovskite oxide heterostructures.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.530-533
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• 2015

기존의 조사에 따르면 현재 소프트웨어 개발 프로젝트의 실패율은 높은 편이다. 미국의 The Standish Group의 보고서에 따르면 소프트웨어 프로젝트의 성공률은 약 32%로 낮음을 볼 수 있다. 소프트웨어 프로젝트 성공에 영향을 주는 요소 중 하나는 인력배치이다. 이는 소프트웨어 개발 프로젝트의 참여 인력 구성에 따라 생산성, 비용 및 개발기간이 달라지게 되기 때문이다. 즉 인력 구성에 따라 프로젝트 성공률에 많은 영향을 주게 될 수 있다. 프로젝트 인력할당은 WBS(Work Breakdown Structure)에 따라 PM(Project Manager) 또는 부서장이 할당하게 되는데, 이들은 프로젝트 구성원들의 상세한 정보까지 파악이 어렵기 때문에 인력구성의 어려움이 존재한다. 과거에 수행했던 개발 프로젝트에서 유사성이 높은 작업을 했음에도 불구하고 전혀 경험이 없는 작업에 할당되면 상대적으로 업무 지식습득에 어려움을 겪고 시간 지연에 따른 비용이 추가적으로 발생하게 된다. 이러한 문제를 해결하고자 본 연구는 소프트웨어 개발 프로젝트 구성원의 상세한 정보들과 소프트웨어 개발 업무와의 유사도 측정을 통해 인력을 업무에 할당하는 기법을 제안한다. 이를 위하여 제안한 기법을 프로토타입으로 구현한 후 현업에서 실제 개발되는 프로젝트에 적용하여 제안 기법의 우수함을 평가한다.

• Mass Spectrometry Letters
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• v.9 no.4
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• pp.91-94
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• 2018

Bilin tetrapyrroles are metabolic products of the breakdown of porphyrins within a species. In the case of mammals, these bilins are formed by the catabolism of heme and can be utilized as either biomarkers in disease or as an indicator of human waste contamination. Although a small subset of bilin tandem mass spectrometry reports exist, limited data is available in online databases for their fragmentation. The use of fragmentation data is important for metabolomics analyses to determine the identity of compounds detected within a sample. Therefore, in this study, the fragmentation of bilins generated by positive ion mode electrospray ionization is examined by collision-induced dissociation (CID) as a function of collision energy on an FT-ICR MS. The use of the FT-ICR MS allows for high mass accuracy measurements, and thus the formulas of resultant product ions can be ascertained. Based on our observations, fragmentation behavior for hemin, biliverdin and its dimethyl ester, phycocyanobilin, bilirubin, bilirubin conjugate, mesobilirubin, urobilin, and stercobilin are discussed in the context of the molecular structure and collision energy. This report provides insight into the identification of structures within this class of molecules for untargeted analyses.

• Elastomers and Composites
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• v.53 no.4
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• pp.202-206
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• 2018

Five solution styrene butadiene rubber/neodymium butadiene rubber (SSBR/NdBR) composites were manufactured using different ratios of SSBR and NdBR. In this study, the composites were reinforced with NdBR and silica to confirm the physical properties of SSBR used for treads of automobile tires and the dispersibility with silica. The morphologies of the rubber composites were observed using field-emission scanning electron microscopy (FE-SEM). The crosslinking behaviors of the composites were tested using a rubber process analyzer (RPA), and the abrasion resistances were tested using a National Bureau of Standards (NBS) abrasion tester. The hardness values, tensile strengths, and cold resistances of the composites were also tested according to ASTM standards. Increased NdBR content yielded composites with excellent crosslinking properties, abrasion resistances, hardnesses, tensile strengths, and cold resistances. The crosslinking point increased due to the double bond in NdBR, thereby increasing the degree of crosslinking in the composites. The NdBR-reinforced composites exhibited excellent abrasion resistances, which is explained as follows. In SSBR, a breakage is permanent because a resonance structure between styrene and SSBR forms when the molecular backbone is broken during the abrasion process. However, NdBR forms an additional crosslink due to the breakdown of the molecular backbone and high reactivity of the radicals produced. In addition, the low glass transition temperature (Tg) of NdBR provided the rubber composites with excellent cold resistances.

• Journal of Semiconductor Engineering
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• v.3 no.2
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• pp.161-167
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• 2022

Electrical characteristics of LDMOS power device with LDD(Lightly Doped Drain) structure is studied with variation of the region of channel and LDD. The channel in LDMOSFET encloses a junction-type source and is believed to be an important parameter for determining the circuit operation of CMOS inverter. Two-dimensional TCAD MEDICI simulation is used to study hot-carrier effect, on-resistance Ron, breakdown voltage, and transient switching characteristic. The voltage-transfer characteristics and on-off switching properties are studied as a function of the channel length and doping levels. The digital logic levels of the output and input voltages are analyzed from the transfer curves and circuit operation. Study indicates that drain current significantly depends on the channel length rather than the LDD region, while the switching transient time is almost independent of the channel length. The high and low logic levels of the input voltage showed a strong dependency on the channel length, while the lateral substrate resistance from a latch-up path in the CMOS inverter was comparable to that of a typical CMOS inverter with a guard ring.