• 농촌계획
• /
• 제18권2호
• /
• pp.69-79
• /
• 2012

This study was carried out to analyze the disparities of basic living infrastructure between Guns(rural counties), and between Eups/Myuns(rural districts) in Jeollanam-do province. For the purpose of this study, dimensions of regional disparity in basic living structure were measured by 3 components ; road, public water service and sewage disposal. By utilizing the published statistics, this study has examined 8 Guns(counties) containing Eup and Myon in Jeollanam-do province which can represent 4 different rural areal types, respectively, i,e. mountainous, semi-mountainous, flat and seashore areas. The data acquisition time of this study is fixed on end of 2009 year in order for possible collections of the most recent published statistics. It presents evidence on the magnitude and evolution of discussion of regional disparities between Guns(counties), and between Eup & Myon, and between Myons in Jeollanam-do province even though infrastructure provision level of Jeollanam-do rural areas are much more improved than the past. Concludingly, the existing disparities in this area is meaningful and so, it should be seriously reconsidered when deciding local government's budget allocation priority.

• 대한기계학회논문집B
• /
• 제39권6호
• /
• pp.541-548
• /
• 2015

본 논문에서는 순차적 화학기상증착법에 기반하여 다양한 구조적 특성을 갖는 산화아연 나노구조체를 탄소나노튜브 상에 3 차원 혼성구조로 형성하는 공정을 개발하고 그 형성 메커니즘을 논한다. 이어서 나노와이어, 나노로드, 나노플레이트, 다결정 나노박막 등 다양한 형상의 산화아연 나노구조를 온도, 압력, 개스유량 등 주요 파라미터들의 조절을 통해 형성할 수 있음을 보이며, 이의 형성 원리에 대해 기본적인 형성 메커니즘과 연계하여 고찰한다. 본 연구 결과를 통해, 압전 및 광전 에너지변환 특성 등 풍부한 기능성을 보유하되 다소 높은 전기저항을 갖는 산화아연 나노구조체를 다양한 포맷으로 양전도성의 탄소나노튜브와 혼성화 함으로써, 각각의 포맷 별로 특화된 보다 폭넓은 응용 분야로의 활용을 구현해 나갈 수 있을 것이다.

• 소성∙가공
• /
• 제15권1호
• /
• pp.3-8
• /
• 2006

The demand fer small and high-capacity optical data storage devices has rapidly increased. The areal density of optical disk is increased by using higher numerical aperture objective lens and shorter wavelength source. A wafer-scale stacked micro objective lens with a numerical aperture of 0.85 and a focal length of 0.467mm for the 405nm blue- violet laser was designed and fabricated. A diffractive optical element (DOE) was used to compensate the spherical aberration of the objective lens. Among the various fabrication methods for micro DOE, the UV-replication process is more suitable fur mass-production. In this study, an 8-stepped DOE pattern as a master was fabricated by photolithography and reactive ion etching process. A flexible mold was fabricated for improving the releasing properties and shape accuracy in UV-replication process. In the replication process, the effects of exposing time and applied pressure on the replication quality were analyzed. Finally, the surface profiles of master, mold and molded pattern were measured by optical scanning profiler. The geometrical deviation between the master and the molded DOE was less than $0.1{\mu}m$. The diffraction efficiency of the molded DOE was measured by DOE efficiency measurement system which consists of laser source, sample holder, aperture and optical power meter, and the measured value was $84.5\%$.

• 한국소음진동공학회논문집
• /
• 제13권12호
• /
• pp.965-971
• /
• 2003

고밀도, 고정밀의 정보저장기를 실현하기 위해서 높은 서보대역이 요구되고 있다 이러한 요구조건을 만족시키기 위해서 이단구동시스템이 도입되었다. 이 시스템은 기존의 VCM을 조동구동기로, 추가적인 밀리엑츄에이터를 미동구동기로 사용하는 것이다. 이를 위해 우리는 압전형 밀리엑츄에이터를 서스펜션 부에 설계하였다 이러한 시스템의 제어를 위하여 PQ 제어 방법을 도입하였으며, 이 방식은 이중입력/단일출력 시스템을 두개의 단일 입출력 시스템으로 단순화시키는 것이다. 이 논문은 PQ 제어 방식을 적용시켜 설계하고. 설계된 제어기의 성능 평가로써 기존의 HDD의 PES을 받아서 외란제어 능력을 평가하는 것이다.

• 공업화학
• /
• 제31권5호
• /
• pp.509-513
• /
• 2020

본 연구는 리튬이온 이차전지의 음극재로서 TiO₂ 마이크로콘/CNT 복합체를 제조하여 배터리의 성능을 측정하였다. 양극산화법을 통해 리튬이온이 저장될 수 있는 넓은 표면적의 나노조각으로 구성된 TiO₂ 마이크로콘 구조를 제조하였다. 이어서 polarization과 전기 영동법을 통해 CNT를 증착하였다. TiO₂ 마이크로콘/CNT 복합체 전극은 전기전도도와 리튬이온 전도도가 향상되어 순수한 TiO₂ 마이크로콘 전극 대비 더 높은 용량과 사이클 안정성을 보였다. 또한 TiO₂ 마이크로콘/CNT 복합체는 최대 20 C의 높은 전류밀도에서도 우수한 수명특성과 속도유지율을 보였다.

• 정보저장시스템학회논문집
• /
• 제5권1호
• /
• pp.47-52
• /
• 2009

Most hard disk drives that apply the ramp load/unload technology unload the heads at the outer edge of the disk while the disk is rotating. The load/unload includes the benefits as like an increased areal density, a reduced power consumption and an improved shock resistance. A lot of papers investigating the effects of the various load/unload parameters such as a suspension tab, a limiter, a ramp and air-bearing surface designs have been published. However, in previous researches, an effect of the suspension is not considered at each load/unload step. In this paper, we focus that a variation of the state matrix affects the load/unload performance on based on a state matrix that is a stiffness matrix of the suspension. Because the state matrix is related to the suspension at each load/unload step, to change the state matrix means the structural change of the suspension. Therefore, we investigated a range of a pitch static attitude(PSA) and a roll static attitude(RSA) for load/unload performance. We also analyzed an effect of the variation of the state matrix a range of load/unload velocity occurred a slider-disk contact. We determined the variation of the state matrix to improve the load/unload performance through comparison of each factor of state matrix.

• 한국주거학회논문집
• /
• 제27권4호
• /
• pp.1-11
• /
• 2016

This study aims to find out the cause of delay by analyzing the process of 12 Core-based Improvement pilot projects, especially focused on lands, buildings, population status. For this purpose, it performed a literature research on maintenance plan reports, various statistics of building and population status analysis, a field research and an individual interview with public officials in charge at local governments of 12 project districts. The findings are as follows; 1) it was difficult to cope flexibly to environmental changes because the core sector was so large that the plan was led to areal improvement. 2) the project was selected without reflecting the characteristics of the core sector and the area of residents-led renovation properly in terms of building status such as building density and old buildings ratio, 3) the coordinator group for socially disadvantaged class in the district was not operated and thus foundation for residents-led renovation was not set up. In conclusion, it should be presented the proper size of the core sector when the core-based residential environment improvement project is initiated in the future. In addition, building status is taken into consideration when designating the core sector and the area of residents-led renovation. The coordinator group needs to be operated from the early stage of the project as well.

• Nuclear Engineering and Technology
• /
• 제42권5호
• /
• pp.576-581
• /
• 2010

KAERI (Korea Atomic Energy Research Institute) fabricated MOX (Mixed Oxide) fuel pellets as a cooperation project with PSI (Paul Scherrer Institut) for an irradiation test in the Halden reactor. The MOX pellets were fitted into fuel rods that included instrumentation for measurement in IFE (Institutt for Energiteknikk). The fuel rods were assembled into the test rig and irradiated in the Halden reactor up to 50 MWd/kgHM. The irradiated fuel rods were transported to the IFE, where ceramography was carried out. The fuel rods were cut transversely at the relatively higher burn-up locations and then the radial cross sections were observed. Micrographs were analyzed using an image analysis program and grain sizes along the radial direction were measured by the linear intercept method. Radial cracks in the irradiated MOX were observed that were generally circumferentially closed at the pellet periphery and open in the hot central region. A circumferential crack was formed along the boundary between the dark central and the outer regions. The inner surface of the cladding was covered with an oxide layer. Pu-rich spots were observed in the outer region of the fuel pellets. The spots were surrounded by many small pores and contained some big pores inside. Metallic fission product precipitates were observed mainly in the central region and in the inside of the Pu spots. The average areal fractions of the metallic precipitates at the radial cross section were 0.41% for rod 6 and 0.32% for rod 3. In the periphery, pore density smaller than 2 ${\mu}m$ was higher than that of the other regions. The grain growth occurred from 10 ${\mu}m$ to 12 ${\mu}m$ in the central region of rod 6 during irradiation.

• Composites Research
• /
• 제25권3호
• /
• pp.65-69
• /
• 2012

본 논문에서는 금속 핀으로 보강된 일체성형 복합재 단일겹침 체결부에 대해, 보강 핀이 체결부의 파손거동에 미치는 영향을 시험으로 연구하였다. 핀의 지름(0.3, 0.5, 0.7 mm)과 밀도(0.5, 2.0, 4.0%)를 달리하여 총 6종류의 시편을 제작하였다. 복합재료와 보강핀은 각각 Toray사의 일방향 탄소-에폭시 프리프레그 T700-12K-31E#2510와 스테인리스 강이다. 핀 밀도가 매우 낮은 한 경우(0.5%)를 제외하고는, 모든 체결부에서 두께방향 핀의 보강으로 인해 초기균열의 발생이 더 빨라지는 것으로 나타났다. 그러나 극한강도는 최대 45%까지 증가하고, 특히 접착면의 완전한 분리 후에도 대변형 상태에서 핀이 추가적인 하중을 지지함으로써, 구조물이 안정적 파괴거동을 갖도록 하는 것을 확인하였다.

• 정보저장시스템학회논문집
• /
• 제2권2호
• /
• pp.130-137
• /
• 2006

The HDD(hard disk drive) using Load/unload(L/UL) technology includes the benefits which are increased areal density, reduced power consumption and improved shock resistance than those of contact-start-stop(CSS). It has been widely used in portable hard disk drive and will become the key technology for developing the small form factor hard disk drive. The main objects of L/UL are no slider-disk contact or no media damage. For realizing those, we must consider many design parameters in L/UL system. In this paper, we focus on lift-off force. The 'lift-off' force, defined as the minimum air bearing force, is another very important indicator of unloading performance. A large amplitude of lift-off force increases the ramp force, the unloading time, the slider oscillation and contact-possibility. To minimize 'lift-off' force we optimizes the slider and suspension using the integrated optimization frame, which automatically integrates the analysis with the optimization and effectively implements the repetitive works between them. In particular, this study is carried out the optimal design considering the process of modes tracking through the entire optimization processes. As a result, we yield the equation which can easily find a lift-off force and structural optimization for suspension.