• 전기학회논문지
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• 제66권12호
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• pp.1740-1744
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• 2017

This paper describes the preparation and characteristics of a battery capacitor and module for solar power system. A cylindrical 30,000F battery capacitor ($60{\times}138mm$) was assembled by using the $LTO(Li_4Ti_5O_{12})$ electrode as an anode and $NMC(LiNiMnCoO_2)-LCO(LiCoO_2)$ as a cathode. The battery capacitor has reduced energy density and power density under high CC(constant current) and CP(constant power) conditions. Battery capacitor module (16V, 11Ah) was fabricated using an asymmetric hybrid capacitor with a capacitance of 30,000F. In order to determine the characteristics of the battery capacitor Module for solar power system, battery capacitor cells were connected in series with active balancing circuit. As a result of measuring the 100w LED lamp, it was discharged at the voltage of 15V~10V, and the compensation time at discharge was measured to be about 4979s. Experimental results show that it can be applied to applications related to solar power system by applying battery capacitor module.

• International Journal of Computer Science & Network Security
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• 제22권9호
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• pp.189-194
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• 2022

The formation of a new world order is primarily caused by new conditions and military operations on the European continent. The intensification of military-political tension led to the formation of new centers of power and gravity, which in turn led to the concentration of weapons and general militarization. Changes in the world order as a result of military conflicts and an increase in hot spots in the world, an increase in threats and the formation of centers of military gravity, the inability of existing institutions to resolve the situation lead to the need to develop new security mechanisms. Studies show that in the current situation, the countries of the Baltic countries are especially actively increasing their level of technologization of the army and militarization in general. The creation of any alliance is always conditioned by the presence of external threats. Naturally, the increase in the number of threats creates preconditions for the development of new forms of cooperation within existing military alliances. It seems obvious that due to the current situation in the context of the military conflict and military aggression of Russia in Ukraine, as well as its constant threats, including to the Baltic countries, there is a need to form a certain alliance that can protect the eastern border of Europe and form a certain border between European countries and aggressor countries. The Baltic countries are actively involved in these processes, in addition, it is the Baltic countries that can enter the new military alliance proposed by Britain, which will unite Poland, Ukraine, the Baltic countries and, possibly, Great Britain.

• 한국기계가공학회지
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• 제14권2호
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• pp.59-66
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• 2015

The production of high value-added products requires efficient processing and this constant demand for complex shape processing has led to the need for hybrid processing. In this study, the surface characteristics of hybrid machining, which combines wire-cut E.D.M and vibration, are examined. The selected experimental parameters are verticality, waveform, amplitude, peak current and frequency. The experimental results provide a guideline for selecting reasonable machining parameters. Surface roughness was improved by increasing the amplitude of the vibration.

• 디자인학연구
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• 제3권1호
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• pp.83-93
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• 1990

The constant evolution of society, culture and scientific technology, coupled with changes in life style and behavioral patterns, has led mankind to peroeive diverse needs for space. Particularly, the rapid structural change in the field of marketing has entailed changes in techinques for construction and presentation of space for an improved marketing environment. To satisfy such new, diverse needs for space, interior designers will have to redefine the "mankind and environmen( concept and examine their design methodology anew. The question of how to design available space for a certain purpose will remain a daunting task for designers in the future, as it has been in the past. In the pursuit of convenience and conformity to mankind's surroundings, every nation has, in common with other nations, basic design elements, design skills and other factors. In designing camercial space in a particular region, it is essential, however, to have a proper understanding of the social economic and cultural context indigenous to that region, as well as the impact on environmental and ecological change and marketing strategy. This study discusses design metholdology for the comming camercial space on the basis of the space concept and current status in Korea, with major emphasis on Korea's regional characteristics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.79-81
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• 1993

We have proposed a new technology compensating reactance component of line and load. Because capacity of SC is static, it is not appropriate to varing reactance and causes SSR problems. TCSC is introduced for the flecxible control of reactance of SC. If SC voltage is varied when the capacitor current is constant, it can be considered that capacity of SC was varied. SO capacity of SC can be controlled by controlling the voltage of SC. Control reference voltage of SC can be obtained from the condition that sum of reactive powers in all parts is zero.

• Journal of Power Electronics
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• 제18권6호
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• pp.1642-1649
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• 2018

A single-stage flyback LED AC-DC converter based on primary-side control under constant current mode is proposed in this study. The proposed converter features low total harmonic distortion (THD) and high power factor (PF). It also consists of a zero-crossing distortion compensation circuit and a variable duty ratio control compensation circuit to deal with the line current distortions caused by fixed duty ratio control. The system model and layout are built in Simplis and Cadence, respectively. The feasibility and performance of the proposed circuit is verified by designing and fabricating an IC controller in the HHNEC $0.35{\mu}m$ 5 V/40 V HVCMOS process. Experimental results show that the PF can reach a level in the range of 0.985-0.9965. Moreover, the average THD of the entire system is approximately 10%, with the minimum being 6.305%, as the input line voltage changes from 85 VAC to 265 VAC.

• 한국전기전자재료학회논문지
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• 제37권4호
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• pp.394-399
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• 2024

An irradiator is developed using two UVA wavelength ranges of SMD LEDs as a curing light source. This module has dimensions of 545×111×300 mm³ and is equipped with a TIR bar-shaped lens made of PDMS silicone resin. The developed irradiator offers high uniformity, with 89% in the centerline of the horizontal axis direction, for two different wavelength ranges of 365 nm and 385 nm. The radiation intensity from the light source module shows highly directional characteristics, and the irradiator provides a maximum irradiance of 1,634 mW/cm² at a working distance of 50 mm. During the initial 5 minutes of operation, the irradiance experiences a rapid decrease. However, this issue is addressed by optimizing the LED's current reduction characteristics and managing the Transistor's temperature rise in the constant current circuit. After continuous operation for approximately 60 minutes. The highest temperature, near the central part of the irradiating surface, reaches 69.7℃, while the lowest temperature, near the edges, is 41.1℃.

• 한국재료학회지
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• 제21권4호
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• pp.236-241
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• 2011

Polysilazane and silazane-based precursor films were deposited on stacked TiN/Ti/TEOS/Si-substrate by spin-coating, then annealed at $150{\sim}400^{\circ}C$, integrated further to form the top electrode and pad, and finally characterized. The precursor solutions were composed of 20% perhydro-polysilazane ($SiH_2NH$)n, and 20% hydropolymethyl silazane ($SiHCH_3NH$)n in dibutyl ether. Annealing of the precursor films led to the compositional change of the two chemicals into silicon (di)oxides, which was confirmed by Fourier transform infrared spectroscopy (FTIR) spectra. It is thought that the different results that were obtained originated from the fact that the two precursors, despite having the same synthetic route and annealing conditions, had different chemical properties. Electrical measurement indicated that under 0.6MV/cm, a larger capacitance of $2.776{\times}10^{-11}$ F and a lower leakage current of 0.4 pA were obtained from the polysilazane-based dielectric films, as compared to $9.457{\times}10^{-12}$ F and 2.4 pA from the silazane-based film, thus producing a higher dielectric constant of 5.48 compared to 3.96. FTIR indicated that these superior electrical properties are directly correlated to the amount of Si-O bonds and the improved chemical bonding structures of the spin-on dielectric films, which were derived from a precursor without C. The chemical properties of the precursor films affected both the formation and the electrical properties of the spin-on dielectric film.

• 디자인학연구
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• 제5권1호
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• pp.37-44
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• 1992

Today, the art and the architecture face up to the problem of loss of direction. So, the derection of post have been lost. This phenomina cause the second loss of direction, because the mode of pre-modernism is underestimated. After all, the mode and philosophy of after-modernism face up to the new crisis of derection. Present artists, archtectures and designers have to acnieve new trial and study for estimation of aestetics and directions. Ultimately, constant exercise and study of philosophy, morpholophy, morphology, current mode and new materials is necessary to search a methodology. This all have to be accomplished by the clear philosophy. The original identity is formed in environmental basis. So, first, architectures, designers, and artist understand native identity, second, we sho have acadenical and practical faculties impose significance. In case of Europe, the change of mode have led paradigm of culture. The great change of social culture have come out the wave of revolution that cross in design, architecture and art. 1920's of modernism evolve 1960's completion. In the change of life style, functionalism have evolved postmodernnism. But, in this change we do not suggest the new derection that form concrete idea and sympathy. This phenomina appear in the end of a centry, and nowaday is that day. This trends effect on artists, architectures, and designers, and design and will be changed. Finally, we need to study of concrete and new direction in this circumstance.

• 한국분무공학회지
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• 제19권1호
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• pp.9-14
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• 2014

Performance of DI diesel engine with high-pressure fuel injection equipment is directly related to its emission characteristics and fuel consumption. So, the electro-hydraulic injector for the common-rail injection system should be designed to meet the precise high fuel delivery control capability. Currently, most high pressure injector in use has a needle driven by the solenoid coil energy or the piezo actuator controlled by charge-discharge of output pulse current. In this study, macroscopic spray approaching method was applied under constant volume chamber to research the performance of three different injectors : solenoid, indirect-acting piezo and direct-acting piezo type for CR direct-injection. LED back illumination for Mie scattering was applied on the liquid spray visible of direct-acting piezo injector, including hydraulic-servo type solenoid and piezo-driven injectors. As main results, we found that a direct-acting piezo injector had better a spray tip penetration than hydraulic-servo injectors in spray visualization.