• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.624-626
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• 1993

The Electrical Charge generated by friction in flowing insulating oil can create hazadous accidents. Neutralization of static charges in the oil during transportation is an obvious method of overcoming the problem of internal electric charge. It is known that SCR(Static Charge Reducer) can neutralize much of this charge by the needle electrode and mixing it with the original charge. In our experiment, a filter to generate static charge was set just befor a measurement pipe, and streaming current from the filter to the earth $I_s$, current from the electrode to the earth $I_e$ and current from the receiving tank to the earth $I_f$ were measured in a steady state. As a result, charge density and needle electrode current increases with increasing of oil temperature. Charge elimination rate decreases with increasing of oil flow rate, and increases with increases of oil temperature. Faraday Cage current decreases with increasing of oil temperature.

• Asian Journal of Atmospheric Environment
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• 제9권2호
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• pp.137-145
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• 2015

This study focused on the measurement of the actual charging state of ambient aerosol particles, which is important for understanding the intricate process of adverse health effects caused by particulate matter (PM). The net electrostatic charging state of $PM_{2.5}$ collected on filter media was measured in this study. The Faraday cage method and surface potential measurements were used in this study. The results showed that the polarities of the net charging state measured using these two methods were in agreement for 42 out of 48 samples (87.5%), and 36 samples (75%) were negatively charged. The filters were not significantly charged by friction between the filters and air not containing PM. Charge addition to or leakage from the filters was not observed over a two-month storage period. Net charging state of $PM_{2.5}$ collected on the filters was concluded to be negative in most cases, based on data's support of the assumption that aerosol charging state is not altered by the process of PM collection using filter.

• 전기학회논문지P
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• 제56권2호
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• pp.65-73
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• 2007

In this study, the pulse charger and voltage regulator are proposed that can reuse the waste lead acid battery. The first we develop the voltage regulator that can reuse the waste lead battery. And the pulse current is applied to the terminal of the waste lead acid battery. The voltage regulator is available principle of the pulse current which can reduce the sulfate to incipient material such as Pb and PbO2. Therefore the internal resistance of the lead acid battery is decreased, the performance of the lead acid battery is improved and the durability is prolonged. The second we develop the pulse charger using the voltage regulator. The pulse charger uses the switch mode of the forward convert method. The pulse charger maintain the constant voltage in state removing the lead acid battery and when it connected the pulse charger, it is converted the charge mode of the constant current immediately. It continues the rapid charge until the full state of the lead acid battery. After that the pulse charger is converted to the charge mode of constant voltage automatically, and then it continues the normal charge. The experiment results show that the effectiveness of the voltage regulator and pulse charger such as the good performance and the prolonged durability in lead acid battery of the small and large capacity.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3359-3366
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• 2023

In this study, a spiking cortical model (SCM) based n-g discrimination method is proposed. The SCM-based algorithm is compared with three other methods, namely: (i) the pulse-coupled neural network (PCNN), (ii) the charge comparison, and (iii) the zero-crossing. The objective evaluation criteria used for the comparison are the FoM-value and the time consumption of discrimination. Experimental results demonstrated that our proposed method outperforms the other methods significantly with the highest FoM-value. Specifically, the proposed method exhibits a 34.81% improvement compared with the PCNN, a 50.29% improvement compared with the charge comparison, and a 110.02% improvement compared with the zero-crossing. Additionally, the proposed method features the second-fastest discrimination time, where it is 75.67% faster than the PCNN, 70.65% faster than the charge comparison and 38.4% slower than the zero-crossing. Our study also discusses the role and change pattern of each parameter of the SCM to guide the selection process. It concludes that the SCM's outstanding ability to recognize the dynamic information in the pulse signal, improved accuracy when compared to the PCNN, and better computational complexity enables the SCM to exhibit excellent n-γ discrimination performance while consuming less time.

• Bulletin of the Korean Chemical Society
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• 제30권9호
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• pp.2061-2065
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• 2009

Two simple algorithm modifications are made to the THRASH data retrieval program with the aim of improving analysis speed for complex Fourier transform ion cyclotron resonance (FTICR) mass spectra. Instead of calculating the least-squares fit for every charge state in the backup charge state determination algorithm, only some charge states are pre-selected based on the plausibility values obtained from the FT/Patterson analysis. Second, a modification is made to skip figure-of-merit (FOM) calculations in the central m/z region between two neighboring peaks in isotopic cluster distributions, in which signal intensities are negligible. These combined modifications result in a significant improvement in the analysis speed, which reduces analysis time as much as 50% for ubiquitin (8.6 kDa, 76 amino acids) FTICR MS and MS/MS spectra at the reliability (RL) value = 0.90 and five pre-selected charge states with minimal decreases in data analysis quality (Table 3).

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 추계학술대회 논문집
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• pp.13-15
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• 2008

Charging or discharging secondary batteries such as a lithium-ion battery is essential in the stage of production and takes long time over two hours. And the charge/discharge system is operated with high switching frequency over several tens kHz. Therefore, to simulate such a system in the conventional way takes very long time and huge files are produced. Finally, the simulation would be unable with general PC class. In this paper, the lithium-ion battery charge/discharge system is analyzed by using state space averaging method. As a result, the simulation time is reduced dramatically and the charge/- discharge characteristics of the lithium-ion battery can be observed.

• 한국주조공학회지
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• 제42권6호
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• pp.347-357
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• 2022

본 연구에서는 주조공장의 장입재 충전 거동을 3차원적으로 시각화하고자 하였다. 장입재와 용해로의 실제 조건을 반영하여 시뮬레이션하였다. 3차원 시각화 시뮬레이션이 제조 현장의 장입재 충전 거동을 사실적으로 잘 구현하는지 확인하였다. 3차원 시각화 시뮬레이션에 의한 현실적인 충전 상태를 이상적인 충전 상태와 비교하였다. 어떤 경우에 두 충전 상태의 차이가 발생하는지 분석하였다. 3차원 시각화 시뮬레이션을 제조 공정에 적용할 경우의 특징을 살펴보았고, 주조 분야에서의 여러 활용 방안을 제안하였다.

• 조명전기설비학회논문지
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• 제22권6호
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• pp.127-133
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• 2008

본 논문에서는 무정전 전원시스템(UPS : Uninterruptible Power Supply)의 에너지 저장용으로 사용되는 납축전지를 최적의 상태로 유지, 관리하는 배터리관리시스템을 설계, 제작하고, 잔존용량을 추정하는 알고리즘을 제안한다. 제안된 배터리관리시스템은 배터리의 충 방전 전류를 제어하여 과방전 및 과충전으로부터 배터리를 보호하며, 충 방전 시 배터리 잔존용량(SOC)을 예측하여 배터리를 최적 상태로 유지하도록 하는 알고리즘이 적용된다. 또한 충 방전 시험기를 이용한 실험과 UPS에 장착한 후 성능 실험을 통해, 제작된 시스템의 성능 및 제안된 배터리 잔존용량 추정 알고리즘의 타당성을 입증한다.

• Bulletin of the Korean Chemical Society
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• 제24권7호
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• pp.916-920
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• 2003

Photoreactions of N-(2,4-dibromonaphthyl)arenecarboxamides in basic medium result in the intramolecular substituted products, 2-aryl-8-bromonaphthoxazoles in moderate yields and further photoreactions of the products afford the reduced products, 2-arylnaphthoxazoles. These reactions are straightforward for syntheses of naphthoxazole derivatives. Since the intramolecular photosubstitution of the bromoarenecarboxamide by the oxygen of its amide group is more effective than the photoreduction of the substituted product, 2-aryl-8- bromonaphthoxazole in basic medium, the intramolecular substituted product, 2-aryl-8-bromonaphthoxazole can be isolated. A charge-transfered excited singlet state of an imidol form of the 2-bromoarenecarboxamide is involved in the photosubstitution, whereas an excited triplet state of the 2-aryl-8-bromonaphthoxzole is closely involved in the photoreduction.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.415-420
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• 2013

Effect of chemical substitution at the para-position of the thiophenoxyl radical has been theoretically investigated in terms of energetics, structures, charge densities and orbital shapes for the ground and first electronically excited states. It is found that the adiabatic energy gap increases when $CH_3$ or F is substituted at the para-position. This change is attributed to the stabilization of the ground state of thiophenoxyl radical through the electron-donating effect of F or $CH_3$ group as the charge or spin of the singly-occupied molecular orbital is delocalized over the entire molecule especially in the ground state whereas in the excited state it is rather localized on sulfur and little affected by chemical substitutions. Quantitative comparison of predictions based on four different quantum-mechanical calculation methods is presented.