• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.93-97
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• 2001

A new compact, low-energy electron beam irradiator has been developed. The core-loss of silicon steels can be reduced by magnetic-domain refinement method. The irradiator was developed for the application of core-loss reduction using the method. The beam energy of the irradiator can be varied from 35 to 80 keV and the maximum current is 3mA. The irradiation area is designed to be $30\times30mm2$ now and will be upgraded to $30\times150mm2$ using a scanning magnet and scanning cone. The electron beam generated from 3 mm diameter LaB6 is extracted to the air for the irradiation of the silicon steels in the air. A special irradiation port was developed for this low-energy irradiator. A havar foil with $4.08{\mu}m$ thickness were used for the window and a cold air-cooling system keeps the foil structure by removing heat at the window. The irradiator system and its operation characteristics will be discussed.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2357-2363
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• 2021

Silicon carbide is widely used in radiation environments due to its excellent properties. However, when exposed to the strong radiation environment constantly, plenty of defects are generated, thus causing the material performance downgrades or failures. In this paper, the two-temperature model (2T-MD) is used to explore the defect recovery process by applying the electronic energy loss (Se) on the pre-damaged system. The effects of defect concentration and the applied electronic energy loss on the defect recovery process are investigated, respectively. The results demonstrate that almost no defect recovery takes place until the defect density in the damage region or the local defect density is large enough, and the probability of defect recovery increases with the defect concentration. Additionally, the results indicate that the defect recovery induced by swift heavy ions is mainly connected with the homogeneous recombination of the carbon defects, while the probability of heterogeneous recombination is mainly dependent on the silicon defects.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.12
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• pp.847-851
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• 2014

The characteristics of dielectric constant and $tan{\delta}$ of low viscosity silicone oils with changing degree of polymerization were investigated. The result shows dipole loss mechanism at low temperature range. The dielectric loss in the range of low frequencies are predominantly of ionic nature with temperature increase. The peak of dielectric loss is the detrapping of the electrons which is were trapped in the localized level of the silicone oils at the frequency of 30 kHz. The increase of ionic conduction is attributed to the presence of ionizable oxidation products and their increased dissociation feature. The activation energy ${\Delta}H$ and dipole moment ${\mu}_d$ were increased whit increasing degree of polymerization.

• Transactions on Electrical and Electronic Materials
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• v.15 no.5
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• pp.245-248
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• 2014

$Pt/Al_2O_3/Si_3N_4/SiO_2/Si$ charge trap flash memory structures with various thicknesses of the $Si_3N_4$ charge trapping layer were fabricated. According to the calculated and measured results, we depicted electron loss in a schematic diagram that illustrates how the trap to band tunneling and thermal excitation affects electrons loss behavior with the change of $Si_3N_4$ thickness, temperature and trap energy levels. As a result, we deduce that $Si_3N_4$ thicknesses of more than 6 or less than 4.3 nm give no contribution to improving memory performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.2873-2892
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• 2019

Reducing the interference to the licensed mobile users and obtaining the energy efficiency are key issues in cognitive heterogeneous networks. A corresponding rate loss constraint is proposed to be used for the sensing-based spectrum sharing (SBSS) model in cognitive heterogeneous networks in this paper. Resource allocation optimization strategy is designed for the maximum energy efficiency under the proposed interference constraint together with average transmission power constraint. An efficiency algorithm is studied to maximize energy efficiency due to the nonconvex optimal problem. Furthermore, the relationship between the proposed protection criterion and the conventional interference constraint strategy under imperfect sensing condition for the SBSS model is also investigated, and we found that the conventional interference threshold can be regarded as the upper bound of the maximum rate loss that the primary user could tolerate. Simulation results have shown the effectiveness of the proposed protection criterion overcome the conventional interference power constraint.

• Journal of Power Electronics
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• v.17 no.4
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• pp.1097-1108
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• 2017

Accurate calculation of the conduction and switching losses of a power electronic converter is required to achieve the efficiency of the converter. Such calculation is also useful for computing the junction temperature of the switches. A few models have been developed in the articles for calculating the switching energy losses during switching transitions for the given values of switched voltage and switched current. In this study, these models are comprehensively reviewed and investigated for the first time for ease of comparison among them. These models are used for calculating the average amount of switching power losses. However, some points and details should be considered in utilizing these models when switched current or switched voltage presents time-variant and alternative quantity. Therefore, an applicable technique is proposed in details to use these models under the above-mentioned conditions. A proper switching loss model and the presented technique are used to establish a new and fast method for obtaining the average switching power losses in any type of power electronic converters. The accuracy of the proposed method is evaluated by comprehensive simulation studies and experimental results.

• Proceedings of the KIPE Conference
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• 1998.11a
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• pp.60-63
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• 1998

The widely used power supply (Switched Mode Power Supply : SMPS) as a source in order to stabilize direct current for electronics or communication systems has merits, when it is compared to the existing source for stability, such as high efficiency, small size, light weight by means of switching process of the semiconductor device which controls the flow of power. However, due to existence of inductors and capacitors used for charging energy, the source part in electronic or communication systems hasn't reached the speed, that is supposed to get, for achieving smaller size and lighter weight. In order to get smallness in size, it is necessary to increase switching frequency. And that makes devices for measuring energy smaller. Nevertheless, the rise switching frequency brings increases in switching loss, inductor loss, and power loss. Also, the occurrence of surge and noise caused by high frequency switching is getting higher. The resonant converter has been considered as one of methods that give solutions for the problems of SMPS and that method have been paid attention as a source technology in electronics and communication.

• Nuclear Engineering and Technology
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• v.27 no.5
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• pp.784-791
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• 1995

This paper describes the counting-loss problem for radiation measurement Multi-channel analyzers and spectrometers adopt various techniques for compensation for counting-losses in process-ing the radiation pulses from a detector. Researchers hate tried to seek the best solution for the problem. However, any absolute solution has not been reached and vendors of radiation instruments use their own algorithms individually. This survey explains the various compensation algorithms with electronic implementation approach. Shortcomings and merits of each algorithm are also reviewed and a direction is suggested of the recommendable development strategy for counting-loss compensation.

• Electrical & Electronic Materials
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• v.8 no.5
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• pp.587-593
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• 1995

Silicone oils used insulating substances exhibit the both of organic and inorganic properties, and it has many superior characteristics such as the high thermal resistance and low thermal oxidation level when compared to other insulation oils. In order to investigate the dielectric loss due to the increase of viscosity, silicone oils of viscosity 1, 2, 5[cSt] had been chosen as the specimen and experiment has been performed in the temperature range of -70[.deg. C] - 65[.deg. C] and frequency range of 30 - 1*10$\^$5/[Hz]. As a result, the linear decrease of loss at low frequency region in high temperature was due to the influence of applying frequency, whereas the increase of loss at high frequency region was contributed by electrode's resistance. And increasing viscosity, the activation energy increased from 3.77[kcal/mole] to 7.21[kcal/mole]. The dipole moment of specimen was become clear 1.48 - 2.26[debyel in high temperature region(5 - 65[.deg. C]) and 1.05 - 1.80[debye] in low temperature region (-70 - -25[.deg. C])respectively.

• Journal of the Korean Solar Energy Society
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• v.29 no.1
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• pp.58-63
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• 2009

In this paper, the power loss due to PV module mismatch in PV string is analyzed and a mismatch compensation method is proposed to improve the efficiency of PV system. The analysis of mismatch loss using PV model simulation reveals that the mismatch module may decrease the total efficiency because the MPPT function of power conditioner make the PV system operate at the local maximum point. The mismatch loss can be severe if the maximum power point current of mismatch module is less than that of string. The proposed compensation method which is simply implemented with a buck type converter shows the possibility to remove the mismatch loss. The effectiveness of the analysis and compensation method is verified by a prototype experiment.