• 한국표면공학회지
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• 제30권1호
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• pp.44-56
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• 1997

Influence of electrochemical etching conditions on capacitance gain of aluminium electrolytic on capacitor foil has been investigated by etching cubic textured high purity aluminum foil in dilute hydrochloric acid. Uniformly distributed etch pit tunnels on aluminum surface have been obtained by pretreatment aluminium foil in 10% NaOH solution for 5 minutes followed by electrochemical etching. Electrostatic capacitance of etched aluminium foil anodized to high voltage increased with the increase of current density, total charge, temperature and concentration of electrolyte up to maximum CV-value and then deceased. Election optical observation of the etched foil revealed that the density of etch of etch pits increased with the increase of current density and concentration of electrolyte. this increase of etch pit density enlarged of the increase of capacitance. However, abnormal high current density and high electrolyte concentration induced the local dissolution of the foil surface which resulted the decrease of foil capacitance.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.738-739
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• 2006

This paper will describe a powder and processing method that facilitates single press-single sintered densities approaching $7.5g/cm^3$. At this sintered density, mechanical properties of the powder metal (P/M) component are significantly improved over current P/M technologies and begin to approach the performance of wrought steels. High performance gears have the added requirement of rolling contact fatigue durability that is dependent upon localized density and thermal processing. Combining high density processing of engineered P/M materials with selective surface densification enables powder metal components to achieve rolling contact fatigue durability and mechanical property performance that satisfy the performance requirements of many high strength automotive transmission gears. Data will be presented that document P/M part performance in comparison to conventional wrought steel grades.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.231-234
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• 2002

This thesis is to introduce development process and application for domestic production of Automation System for High Density and Perpendicular Storage used in the industrial field. Most of the traditional Automation Systems for High Density and Perpendicular Storage are imported and using in the industrial field. As a result of this condition, foreign competitive power is decreased cause increasing of production cost. In spite of economical burden to protect a loss with management in the case of the industrial field dealing with various products, imported Automation System for High Density and Perpendicular Storage is used. On this developed Automation System for High Density and Perpendicular Storage solved these problems. Developed system uses managing computer, it is easy to manipulate input and output of production and inventory management. Moreover, Developed system accomplished shortened driving time and mechanical safety.

• 한국전기전자재료학회논문지
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• 제11권4호
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• pp.261-266
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• 1998

In developing the high density memory device, the etching of fine pattern is becoming increasingly important. Therefore, definition of ultra fine line and space pattern and minimization of damage and contamination are essential process. Also, the high density plasma in low operating pressure is necessary. The candidates of high density plasma sources are electron cyclotron resonance plasma, helicon wave plasma, helical resonator, and inductively coupled plasma. In this study, planar type magnetized inductively coupled plasma etcher has been built. The density and temperature of Ar plasma are measured as a function of rf power, flow rate, external magnetic field, and pressure. The oxide etch rate and selectivity to polysilicon are measured as the above mentioned conditions and self-bias voltage.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.1938-1939
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• 2001

시스템을 입력과 출력간의 함수관계로 볼 때 출력에 대한 상대차수가 정의되지 않는 점을 특이점이라고 정의할 수 있다. 본 논문에서는 적절한 기하학적 조건을 만족하는 해석적인 시스템(analytic system)에 대하여 그러한 특이점의 성질을 살펴본다. 특이점을 지나는 궤적은 특이점의 특이도와 그에 관련된 함수 값의 부호에 의해서 특이점의 주변에서는 특이 매니폴드를 기준으로 한 영역에서 나머지 다른 영역으로 통과하거나 혹은 그를 기준으로 어느 한 쪽의 영역에만 머물러 있게 됨을 보임으로써 특이점과 이를 지나는 궤적의 상관관계를 명확히 규명하였다.

• 한국축산식품학회지
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• 제24권3호
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• pp.209-215
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• 2004

본 시험은 고에너지 수준의 사료를 급여한 돼지의 사양성적, 돈육의 도체 특성, 일반성분, 이화학적 특성 및 지방산 조성에 미치는 영향을 조사하기 위해 실시하였다. 80$\pm$3 kg의 삼원교잡종 120두를 공시하여 비육돈 사료 변화의 영양소 수준에 따라 저에너지 DE 3,290 kcal/kg, CP 14.5%, Lysine 0.70%, Ca 0.78로 배합한 사료를 38일간 급여하였고, 고에너지 DE 3,350 kcal/kg, CP 15.0%, Lysine 0.10%, Ca 0.78%로 배합한 사료를 27일간 급여하였다. 저에너지와 고에너지 사료를 급여한 돼지의 종료체중이 101 kg내외에 도달했을 때 도축하여 시험에 공시하였다. 고에너지 사료를 급여한 돼지가 일당 증체량이 높았고, 사료섭취량과 사료요구율은 낮았다(p<0.05). 도체특성과 일반성분은 차이를 보이지 않았다 이화학적 특성 중 고에너지 사료를 급여한 돈육의 가열 감량과 황색도는 저에너지 사료를 급여한 돈육에 비해 현저히 높게 나타내었다(p<0.05). 지방산 조성에서는 저에너지와 고예너지 사료를 급여한 돈육에서 차이를 보이지 않았다. 이상에서 고에너지 사료를 27일간 급여한 돼지는 저에너지 사료를 38일간 급여한 돼지에 비해 성장률이 향상되었고, 돼지의 도체 특성, 물리적 특성 및 지방산 조성에는 미치지 않았지만 돈육의 가열 감량과 황색도가 높았다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.2092-2094
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• 2000

As a next generation lithography (NGL) technology for VLSI semiconductor fabrication, electron beam, ion beam, X-ray and extreme ultraviolet(EUV) are considered as possible candidates. Among these methods, EUV lithography(EUVL) is thought to be the most probable because it is easily realized by improving current optical lithography technology. In order to set EUV radiation which can be applied to EUVL, it is essential to generate very high density and high temperature plasma stably. The method using a pulse power laser and a high voltage pulse discharge is commonly used to accomplish such a high density and high temperature plasma. In this paper we review the recent trends of the EUV generation technique by high density and high temperature plasma.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 추계 학술논문 발표대회
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• pp.79-80
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• 2016

In this study, we measured the relative density and the compressive strength in order to select the appropriate W/ B for the ultra-high strength concrete development. If W/B is lowered than the W/B of highest relative density, it was confirmed that the strength is lowered. However, if water is increased than the W/B of highest relative density, the relative density is decreased compressive strength was similar. The selection of the W/B of the lower than the highest relative density is not appropriate. Appropriate W/B is selected to be more than the maximum relative density of W/B.

• 전력전자학회논문지
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• 제21권2호
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• pp.95-101
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• 2016

This paper proposed a high-power density bidirectional converter for hybrid electric vehicle high-voltage DC-DC converter(HDC). The conventional HDC has two disadvantages. First, large inductance is required to satisfy the ripple current of inductor by low switching frequency (<20 kHz). Second, large core size is required to prevent the saturation of inductor by high current. Compared with the conventional HDC, the proposed HDC can reduce inductance with SiC-FET for high frequency driving. High-power density of I/O capacitors can be achieved through two-phase interleaved method. The high-power density of inductors can be achieved because the offset current of magnetizing inductance is theoretically terminated by using the differential mode coupled inductor instead of using two single inductors. The validity of the proposed converter is proved through the 50 kW prototype.

• Journal of Astronomy and Space Sciences
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• 제27권4호
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• pp.329-335
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• 2010

We investigate the sources of the variation of the high-latitude thermospheric neutral mass density depending on the interplanetary magnetic field (IMF) conditions. For this purpose, we have carried out the National Center for Atmospheric Research Thermosphere-Ionosphere Electrodynamics General Circulation Model (NCAR-TIEGCM) simulations for various IMF conditions under summer condition in the southern hemisphere. The NCAR-TIEGCM is combined with a new empirical model that provides a forcing to the thermosphere in high latitudes. The difference of the high-latitude thermospheric neutral mass density (subtraction of the values for zero IMF condition from the values for non-zero IMF conditions) shows a dependence on the IMF condition: For negative $B_y$ condition, there are significantly enhanced difference densities in the dusk sector and around midnight. Under the positive-$B_y$ condition, there is a decrease in the early morning hours including the dawn side poleward of $-70^{\circ}$. For negative $B_z$, the difference of the thermospheric densities shows a strong enhancement in the cusp region and around midnight, but decreases in the dawn sector. In the dusk sector, those values are relatively larger than those in the dawn sector. The density difference under positive-$B_z$ condition shows decreases generally. The density difference is more significant under negative-$B_z$ condition than under positive-$B_z$ condition. The dependence of the density difference on the IMF conditions in high latitudes, especially, in the dawn and dusk sectors can be explained by the effect of thermospheric winds that are associated with the ionospheric convection and vary following the direction of the IMF. In auroral and cusp regions, heating of thermosphere by ionospheric currents and/or auroral particle precipitation can be also the source of the dependence of the density difference on the IMF conditions.