• Corrosion Science and Technology
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• 제4권1호
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• pp.1-7
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• 2005

An alternating current (AC) corrosion on buried pipeline has been studied using coupon and ER probe. Coupons and ER probes were applied to the sites from high value of AC voltage to low value based on the survey of AC voltages on buried gas transmission pipeline over the country. Parameters such as AC current density of coupon, AC voltage, cathodic protection potential, soil resistivity and frequency were monitored continually. Corrosion induced by AC was observed even under cathodically protected condition that met cathodic protection criterion (; below -850 mV vs. CSE). Corrosion rate was affected mainly not by AC voltage but by both of frequency and AC current density. An experimental corrosion rate relation could be obtained according to effective AC current density, in which AC corrosion rate increased linearly with effective AC current density, and its slope was 0.619 in coupon method and 0.885 in ER probes.

• 전력전자학회논문지
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• 제23권2호
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• pp.147-151
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• 2018

Phase-shift fullbridge (PSFB) converter detects the current in the primary side for operation of the peak current mode controller (PCMC). The PCMC must used the slope compensation to solve the problem when the effective duty is over 0.5. The voltage response of PSFB converters has slower than that of buck converter because of slew interval even if the voltage controllers of two converters have same bandwidth. To overcome these problems, this work proposes a compensating method of current reference considering slew interval and fast response in the PSFB converter. The effectiveness of the proposed method is proven using the PSIM simulation and experiment.

• 전기학회논문지
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• 제59권7호
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• pp.1194-1198
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• 2010

A high temperature superconducting power cable (HTS power cable) was applied large current capacity by no resistance in normal state. Fault state was risen out of over-current but, it was limited to resistance. this study was modeling equivalence, and unbalanced state analyzed operating charateristics of HTS power cable. The equivalence model was composed superconductor, shield, and former part. This model simulation was appeared conductor and shield current in normal state, but fault state was appeared former current as rise current by resistance. so it need to sufficiently influenced the quench characteristic when the former design.

• 전기학회논문지
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• 제59권2호
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• pp.465-470
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• 2010

The charge pump in a phase-locked loop is a key block in determining reference spurs of the VCO output signal. To reduce reference spurs, the current mismatch in the charge pump must be minimized. This paper presents a dual compensation method to reduce the current mismatch. The proposed charge pump and PLL were realized in a $0.18{\mu}m$ CMOS process. Measured current matching characteristics were achieved with less than 1.4% difference and with the current variation of 3.8% in the pump current over the charge pump output voltage range of 0.35-1.35V at 1.8V. The reference spur of the PLL based on the proposed charge pump was measured to be -71dBc.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.633-634
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• 2005

Transparent conducting glasses exhibit high ohmic losses that are apparent in the case of large size Dye Sensitized Solar Cells (DSSCs). In this study, we investigated the impact of current collectors over the efficiency of DSSCs. The Silver current collectors were prepared on both counter electrode and working electrode surface by screen printing method. For long term stability in electrolyte environment and also to avoid the charge recombination, current collectors are protected by sodium silicate overcoat layer. These current collectors were characterized for their microstructure parameters. Also current collector's stability in electrolyte environment has been investigated.

• Ocean Science Journal
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• 제42권1호
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• pp.19-30
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• 2007

This study analyzed the current meter records along with wind records for over 500 days obtained in the Kangjin Bay, South Sea, Korea spanning from March, 2003 to Nov. 2005. Various analyses include descriptive statistics, harmonic analysis of tidal constituents, spectra and coherence, the principal axis, progressive vector diagrams. These analyses can illustrate the response of residual current to the local wind resulting in the net drift with rotational motion. Current speed ranges from -28 to 33 (cm/sec), with standard deviations from 6.5 to 12.9 (cm/sec). The harmonic analyses of the tidal current show the average form number, 0.12 with semi-diurnal type and the rectilinear orientation of the major axis toward northeast. The magnitudes of the semi-major range from 12.7 to 17.7 (cm/sec) for M2 harmonics, while for S2 harmonics, they range from 6.3 to 10.4 (cm/sec), respectively. In the spectral and coherency analysis of residual current and wind, a periodicity of 13.6 (day) is found to be most important in both records and plays an important role in the net drift of residual current. The progressive vector diagrams of residual current and wind show two types of behaviors such as unidirectional drift and rotational motion. It was also found that 3 % rule holds approximately to drive 1 (cm/sec) drift current by 30 (cm/sec) wind speed based on the correlation of the semi-major axis of wind and residual current.

• 조명전기설비학회논문지
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• 제26권11호
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• pp.75-80
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• 2012

In this paper, the operational characteristics due to the introduction of the superconducting fault current limiter(SFCL) with a peak current limiting function were analyzed in the power distribution system. The parallel structure of the superconducting element can operate the peak current limiting function depending on the transient amplitude of fault current. We studied the operating characteristics of the introduction of the SFCL with a peak current limiting function in the power distribution system. Furthermore, we were analyzed between the SFCL with a peak current limiting function and the protection devices in the power distribution system, through the short circuit experiments.

• 전기화학회지
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• 제19권3호
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• pp.57-62
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• 2016

The over-discharging phenomena in sodium-nickel chloride batteries were investigated in relation to decomposition of molten salt electrolyte and consequent metal co-deposition. From XRD analysis, the material deposited on graphite cathode current collector was revealed to be by-product of molten salt electrolyte decomposition. In particular, the result showed that the Ni-Al alloys ($Al_3Ni_2$, $Ni_3Al$ and $Al_3Ni$) were electrochemically deposited on graphite current collectors in line with over-discharging behaviors. It is assumed that the $NiCl_2$ solubility in molten salt electrolytes leads to the co-deposition of Ni-Al alloys by increasing metal deposition potential above 1.6 V (vs. $Na/Na^+$). The cell tests have revealed that the composition of molten salt electrolytes modified by various additives makes a decisive influence on the over-discharging behaviors of the cells. It was revealed that NaOCN addition to molten salt electrolytes was advantageous to suppress over-discharge reactions by modifying the characteristics of molten salt electrolytes. NaOCN addition into molten salt electrolytes seems to suppress Ni solubility by maintaining basic melts. The cell using modified molten salt electrolyte with NaOCN (Cell D) showed relatively less cell degradation compared with other cells for long cycles.

• 한국콘텐츠학회논문지
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• 제22권4호
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• pp.70-82
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• 2022

4단계 이전의 자율주행은 반자율주행 단계로 차량이 주행을 하다가 운전자에게 빠르게 제어권을 넘겨야 하는 상황이 반복적으로 벌어진다. 하지만 지금의 자율주행 차량은 제어권을 넘길 때 일괄적으로 간단한 메시지와 경고음만을 사용해 운전자에게 알림을 주고 있어 개개인의 특성에 대한 고려나 다양한 위급 상황에 대한 설명을 제대로 전달하지 못하고 있다. 본 연구에서는 자율주행 차량의 판단에 대한 시·청각 정보 제공 정도와 운전자의 운전 효능감이 제어권 전환 요청 상황에서 운전자의 판단과 행동에 미치는 영향을 살펴보았다. 연구 결과 제어권 전환 요구 시 제공된 시·청각 정보 조합 방식에 따른 운전자의 인지 부하, 신뢰도, 안전감, 사용성 및 유용성의 설문 항목에서 조건에 따라 유의한 차이가 있는 것을 확인할 수 있었다. 본 연구를 통해 운전자의 운전 효능감에 따라 제어권 전환 상황에서 요청을 전달하는 효율적인 정보 제공 방식이 달라진다는 인사이트를 발견할 수 있었다. 급박한 제어권 전환 상황에서 운전자의 특성을 고려한 요청이 이루어져야 한다는 본 연구의 결과는 보다 안전하고 효율적으로 운전자와 소통할 수 있는 자율주행 차량을 설계하는데 도움을 줄 수 있을 것으로 기대한다.

• 대한전자공학회논문지SD
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• 제42권5호
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• pp.9-14
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• 2005

본 논문은 순수한 고주파 (radio-frequency: rf) 모드의 반사형과 투과형 고주파 단일전자 트랜지스터 (RF-SET) 동작의 새로운 시뮬레이션 기법을 소개한다. 이 기법은 RF-SET 회로를 주파수 영역에서 self-consistent 방법으로 키리히호프 법칙에 기반한 미분 방정식의 해를 구한다. 또한, 이 기법은 정상상태와 시변 단일전자 트랜지스터 전류 모델들 두 가지를 포함한다. 순수한 rf 모드 반사형 RF-SET의 반사파와 순수한 rf 모드 투과형 RF-SET의 투과파를 계산한다. 정상상태 단일전자 트랜지스터 전류 모델을 포함한 RF-SET 계산의 정확성은 [참고문헌 2]에서 소개된 방법으로 확인한다. GHz 이상의 고주파에서 시변 단일전자 트랜지스터 전류 모델을 포함한 RF-SET 계산 결과는 정상상태 단일전자 트랜지스터 전류 모델을 포함해서 RF-SET를 계산한 결과들과 상당한 차이가 있음을 확인했다. GHz 이상 고주파에서 RF-SET 동작 분석은 정확한 시변 단일전자 트랜지스터의 전류 모델이 요구된다.