• 정보저장시스템학회:학술대회논문집
• /
• 정보저장시스템학회 2005년도 추계학술대회 논문집
• /
• pp.223-228
• /
• 2005

In oprical disk drives, surface defects on a disk distort tracking error signal and disturb a precision tracking control.. A conventional method against disk defect is held the tracking control signal when a defective portion is detected. However, if the defective portion is getting longer, objective lens will get away from following track. In order to keep the postion of spot from following track, the servo system must predict tracking error and control the object lens in the defective portion. A tracking control system for optical disk drives was proposed recently based on both Coprime Factorization(CF) and Zero Phase Erro. Tracking(ZPET) control. The system was proposed for overcome the limit of previously tracking error. But there were no research about the method against the defective portion. This paper proposes a new and simple ZPET construct. as a new method against the defective portion. From experimental results, we have proved that proposed method improves the performance against the defective portion, decreases the uncertainty of a model, and requires less memory than the previously proposed method.

• 신재생에너지
• /
• 제5권3호
• /
• pp.26-31
• /
• 2009

Using MBE growth method, GaAs/AlGaAs solar cell structure was grown. Deposited electrodes are Au/Ni/Ge for n-type and Au/Pt/Ti for p-type electrodes were deposited by E-beam evaporator. Indoor light concentrators were devised and fabricated in order to concentrate artificial solar rays. Also mirror and prism and Fresnel lens concentration system with solar simulator were devised and fabricated. Results of solar cell characteristics were measured with shutting system which can control the amount of light. Maximum power density was 2.13 W/$cm^2$ and maximum concentration was 124 sun, when mirror with Fresnel lens was used at $7854\;mm^2$ of shutter hole.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.401-404
• /
• 2004

The electron beam machining provides very high resolution up to nanometer scale, hence the E-beam writing technology is rapidly growing in MEMS and nano-engineering areas. In the optical column of the e-beam writer, there are several lenses condensing and focusing electron beams from electron gun with fringing magnetic fields. To achieve small spot size as 1-2 nm for higher power of electron beam, magnetic lenses should be designed considering their magnetic field distribution. In this paper, the magnetic field at two condenser lenses and object lens are calculated with finite element method and discussed its performances.

• 생약학회지
• /
• 제34권4호통권135호
• /
• pp.314-317
• /
• 2003

Inhibitory effects of the whole extract and isolated compounds from the leaves of Vaccinium koreanum (Ericaceae) on rat lens aldose reductase (RLAR) and on platelet aggregation were investigated for the prevention or the treatment of chronic diabetic complications. Arbutin, isolated from n-butanol fraction of methanol extract, exhibited a potent inhibitory effects on rat platelet aggregation induced by ADP $(IC_{50}=0.12\;{\mu}M)$ and collagen $(IC_{50}=0.039\;{\mu}M)$ and showed same inhibitory activities with positive control, tetramethylene glutaric acid, on RLAR.

• 한국항행학회논문지
• /
• 제14권1호
• /
• pp.11-19
• /
• 2010

본 논문에서는 밀리미터파대역에서 동작하는 H면 여파기 결합 안테나를 제안하였다. 여파기 결합 안테나는 여파기가 안테나에 삽입된 형태이며 안테나의 반사손실을 줄이고 지향성을 높이기 위하여 다층의 유전체 렌즈가 결합되었다. 도파관 형태의 여파기와 안테나는 가상의 도체벽을 형성하는 via의 배열을 PCB기판에 구현함으로서 크기의 감소를 꾀하였으며 안테나와 여파기를 일반적인 도파관에서 설계한 후 PCB 기판에 축소하여 구현한 후 결합을 시도하였다. 유전체 렌즈의 두께를 조절하기위해 단층 및 다층의 유전체 기판을 사용하였으며 그 결과로 41.5 GHz의 중심주파수에서 8, 13.5 dBi의 시뮬레이션 이득을 각각 얻을 수 있었다.

• 한국생산제조학회지
• /
• 제26권3호
• /
• pp.328-336
• /
• 2017

The exit surface of a lens is designed using a three-dimensional free-form expression in order to easily modify a curved surface. This enables the design of numerical values and mathematical things using three-dimensional free-form expression, and enhances precision because it can be fine-tuned via numerical control. The standard of "Classification of Luminaire Light Distribution" for outdoor lighting fixtures by IESNA is adopted in order to examine the correlation between three-dimensional free-form surface expression and lighting performance. The variation of light distribution type and range is analyzed using the values of maximum light intensity and 50% light intensity. The actual tolerance occurs owing to parameters such as the thickness of the lens, the distance between LEDs, and the movement of the center of the incident surface; the effects of changes in these parameters on the performance are compared and analyzed.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 G
• /
• pp.2515-2517
• /
• 1998

The micro fresnel lens(MFL) was modeled and fabricated on a XY-stage electrostatically driven by comb actuator. The modeled MFL was approximated as a step shape with 4-phase and 4-zone plate. The focal length and diameter of the MFL is 20mm and 912${\mu}m$, respectively. The XY-stage suspending the MFL is designed to generate a large static displacement up to about 20${\mu}m$. On SOI substrates, we first fabricated MFL using the RIE(reactive Ion etching) technology and then patterned and etched bulk silicon to make XY-stage. After the fabrication of all structures on top side of the SOI substrates. $Si_3N_4$ was deposited for passivation of all structures using PECVD(plasma enhanced chemical vapor deposition). All the MFL systems width comb drive actuator were released by KOH etching from the bottom side of the SOI wafer using double-sided alignment technique. In fabrication of MFL, a dry etching conditions is established in order to improve surface roughness and to control the etched depth.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2003년도 생물공학의 동향(XIII)
• /
• pp.428-433
• /
• 2003

소수성인 RGP lens의 관리용액인 6개사의 다목적용액(multipurpose solution, MPS)의 습윤성 접촉각과 표면장력, 점도를 측정하여 비교해 보았다. 결과는 RGP 렌즈를 8시간 MPS에 담근 후 인공누액을 떨어뜨려 측정한 접촉각은 $25^{\circ}-36^{\circ}$의 범위로 렌즈와 MPS는 비교적 우수한 습윤성을 보여주었으며, 표면 장력은 19.8-31.3 mN/m의 값이 얻어졌다. 각각의 다목적용액에 렌즈를 홀더에 얹은 상태로 계면과 렌즈가 분리될 때의 표면장력을 측정하였을 때는 26.5-33.5 mN/m의 값이 측정되었다. 점도는 4^{\circ}C$와 28^{\circ}C$에서 측정했으며 측정온도에 따라 온도가 낮을수록 높게 측정되었고, MPS의 온도 28^{\circ}C$에서 점도는 9.5-65.5 cps를, 4^{\circ}C$에서는 6.5-13.7 cps의 값을 보였다. RGP lens MpS는 soft lens MPS에 비해 접촉각과 표면장력은 낮고, 점도는 높아서 습윤성이 더 우수하였고 제조회사에 따라 습윤성의 차이가 있었다.

• 정보저장시스템학회논문집
• /
• 제10권1호
• /
• pp.1-6
• /
• 2014

Plasmonic lithography is the latest technique to overcome diffraction limit of previous optical lithography. In the plasmonic lithography, the nano gap between nano metal wave guide and photoresist should be in sub-wavelength region. SIL-based plasmonic lithography is the one of the solutions to maintain small air gap. However, the nano gap control is so sensitive that a little disturbance is able to have a large effect on the nano gap control. So, we analyzed the characteristics of disturbance, and then modified the previous controller to suppress the disturbance. We applied two peak filters which were fixed one and adaptively changeable one. We experimentally confirmed the improvement of the nano gap control, which reduced nano gap error by 30 %. The proposed control will improve the quality of lithography pattern.

• 한국광학회지
• /
• 제12권2호
• /
• pp.109-114
• /
• 2001

광학설계의 최적화에서는 광학수차를 줄이면서 광학계의 제한조건을 유지시켜야하며, 이를 위하여 Lagrange 부정승수법이 사용되고 있다. 이 과정에서 제한조건이 merit function의 error 항보다 우선적으로 보정된다. 본연구에서는 이를 이용하여 merit function에서 절대값이 큰 error의 보정조건을 제한조건으로 변경하여 우선적으로 보정하는 최적화의 능동적 제어법을 제안하고 이를 사진렌즈계의 최적화에 적용하였다.