• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.161.1-161.1
• /
• 2016

박막 태양전지의 광 산란을 위한 텍스쳐 된 표면은 반사 손실을 감소시키기 위한 것이다. 그러나, 투명한 전극(TCO)의 텍스쳐 된 표면은 빛의 가용성을 제한하고, 장파장 영역에서 haze의 수치를 감소시키며, 전반사의 증가는 박막 태양전지의 Jsc를 감소시킨다. 본 논문에서는 높은 빛의 가용성을 위하여 HF+HCl 혼합용액을 이용하여 표면의 질을 향상시키기 위한 해결책을 제시했다. 같은 HF+HCl 혼합용액을 사용하여, 540 nm의 파장에서 약 85 %의 높은 haze 수치를 달성했으며, ZnO:Al 막의 증착 후에 식각된 유리 기판과 함께 비교했을 때, 2.3%의 haze 수치의 감소를 얻었다. 또, 깊은 습식 식각에 의하여 Haze 수치를 증가시키기 위한 메커니즘 간단히 설명했다. 텍스쳐 된 유리 기판의 haze 수치의 측면에서 광학 이득은 일반적인 Asahi FTO 유리(${\lambda}=540nm$의 13.5%)에 비해 상당히 높다. 이러한 높은 haze 수치의 AZO 박막은 박막 태양전지의 Jsc를 개선하는데 이용할 수 있다.

• 한국분말재료학회지
• /
• 제16권5호
• /
• pp.305-309
• /
• 2009

The effect of light scattering layers (400 nm, TiO$_2$ particle) of 4 $\mu$m thickness on the dye-sensitized solar cell has been investigated with a 12 $\mu$m thickness of photo-anode (20 nm, TiO$_2$ particle). Two different structures of scattering layers (separated and back) were applied to investigate the light transmitting behaviors and solar cell properties. The light transmittance and cell efficiency significantly improved with inserting scattering layers. The back scattering layer structure had more effective transmitting behavior, but separated scattering layer (center: 2 $\mu$m, back: 2 $\mu$m) structure (9.83% of efficiency) showing higher efficiency (0.6%), short circuit current density (0.26 mA/cm$^2$) and fill factor (0.02). The inserting separating two scattering layers improved the light harvesting, and relatively thin back scattering layer (2 $\mu$m of thickness) minimized interruption of ion diffusion in liquid electrolyte.

• Journal of Biosystems Engineering
• /
• 제32권3호
• /
• pp.173-178
• /
• 2007

This research was conducted to develop and analyze a wireless monitoring system for judging if sick or dead layers (SDL) exist in multi-tier layers battery (MLB) by machine vision, and to evaluate the performance between a wired monitoring system and it. This study used the AP (Access Point), the RS-285 to RS-232 converter, RS-232 to Ethernet converter, PICBASIC board and upgraded lump image processing method to change wired monitoring system into wireless monitoring system. The system was tested at a pilot farm and farm layer house. Results showed that monitoring judgement success rate at a pilot farm on normal cage (without SDL) was 82.3% and that on abnormal cage (with SDL) was 87.5%, respectively. And communication performance test results showed at farm layer house was $700{\sim}900$ kbps while equipments operated. There were dropped slightly than performance of wired monitoring system, however, the quantity was too small to make a significant difference of performance of the controling system developed for wireless communication.

• Journal of Biosystems Engineering
• /
• 제34권1호
• /
• pp.37-43
• /
• 2009

Hyperspectral reflectance and fluorescence scattering have been researched recently for measuring fruit post-harvest quality and condition. And they are promising for nondestructive detection of fruit quality. The objective of this research was to develop a model, which measure the quality of apple by using hyperspectral reflectance and fluorescence. A violet laser (408 nm) and a quartz tungsten halogen light were used as light sources for generating laser induced fluorescence and reflectance scattering in apples, respectively. The laser induced fluorescence and reflectance of 'Golden Delicious' apples were measured by using a hyperspectral imaging system. Fruit firmness, soluble solids and acid content were measured using standard destructive methods. Principal component analyses were performed to extract critical information from both hyperspectral reflectance and fluorescence data and this information was then related to fruit quality indexes. The fluorescence models had poorer predictions of the three quality indexes than the reflectance models. However, the prediction models of integrating fluorescence and reflectance performed consistently better than the individual models of either reflectance or fluorescence. The correlation coefficient for fruit firmness, soluble solid content, and tillable acidity from the integrated model was 0.86, 0.75, and 0.66 respectively. Also the standard errors were 6.97 N, 1.05%, and 0.07% respectively.

• 한국연소학회지
• /
• 제1권1호
• /
• pp.75-82
• /
• 1996

Laser induced incandescence, LII, recently developed technique for measuring soot concentration in flames, can overcome most of limitations of conventional laser extinction measurement. In this study, experiments were performed to investigate the effect of laser intensity, detection wavelength, and also laser beam quality on both LII signal at a particular position and peak-to-centerline LII signal ratio. The results of LII signal with increasing laser intensity shows its near-independence of laser intensity once threshold level of laser intensity has been reached. However, this near-independence depends on laser beam quality and the incident optical setup. The peak-to-centerline LII signal ratio slowly but continuously increases with laser power. This fact is due to the dependence of LII signal on particle mean diameter. LII signal is attenuated during it passes through the flame containing soot particles. The attenuation rate is inversely proportional to detection wavelength. In this study, LII signal at 680 nm band is 10% greater than the signal at 400 nm band.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2011년도 추계학술대회
• /
• pp.94-95
• /
• 2011

선박 엔진 크랭크 케이스 내부의 기계 결함으로 발생하는 윤활 오일 미스트 발생은 폭발뿐만 아니라 급격한 온도와 압력상승으로 2차 폭발을 야기하는 등 큰 피해를 가져와 현재 선박용 엔진의 크랭크 케이스에 오일미스트 검출장치의 설치를 의무화 하고 있는 추세이다. 본 논문에서는 이러한 피해를 줄이기 위하여 광 산란 방식을 이용한 오일 미스트 검출장치를 구현하였으며, 구현된 오일미스트 검출 장치의 오일미스검출 센서 센싱 성능은 전기적, 광학적 그 외 환경적 요인으로 인하여 출력값이 일정하지 못해 각각의 오일미스트 검출 센서를 보정해야 한다. 본 논문에서는 크랭크케이스마다 장착되는 오일미스트 검출 센서의 오차를 최소화하기 위하여 정밀하게 Calibration된 Reference Data를 기반으로 최소자승법을 적용하여 센서를 Calibration하였으며, 그 결과 각각의 오일미스 검출센서의 오차를 기존 방법과 비교하여 최소화할 수 있었다.

• 대한전자공학회논문지SD
• /
• 제37권2호
• /
• pp.22-27
• /
• 2000

본 논문에서는 체적흘로그래픽 메모리를 이용한 스테레오스코픽 동영상 디스플레이 시스템을 제안하였다. 각다중화된 스테레오스코픽 영상 페어의 다중 홀로그램들이 방대한 저장 능력과 실시간 랜덤 엑세스의 장점을 갖는 동일한 광굴절 매질에 기록되었다. 브래그 조건을 만족하는 입사파는 기록된 회절 격자에 의해 산란되어 스테레오스코픽 영상 페어의 방향을 따라 회절된다. 디스플레이 평면으로 회절되어 투사된 연속적인 좌안과 우안 영상으로부터 입체 비디오 영상을 관찰할 수 있다.

• 한국전기전자재료학회논문지
• /
• 제22권4호
• /
• pp.307-313
• /
• 2009

Quantitative analysis of optical scattering intensities from a Au nanoparticle with a diameter of 100 nm, which is effected by the localized surface plasmon resonance (LSPR), were numerically carried out by using a dark-field detection scheme on prism basal plane for two different beam incident modes of reflectance (R-mode) and transmittance (T-mode). Two-dimensional finite difference time domain (FDTD) algorithm was adopted, and its applicabilibility was verified by comparing the simulation results with the theoretical ones. Simulation results of the scattered light intensities from a Au nanoparticle revealed that the scattered intensity of the T-mode was much stronger than that of R-mode. Comparison of the calculated results with the theoretical intensity distribution on the prism showed that the scattered intensity is marimized when the evanescent field, which is generated from the interface of prism and air at TIR angle, is coupled with Au nanoparticle.

• 대한기계학회논문집B
• /
• 제30권4호
• /
• pp.287-297
• /
• 2006

The Holographic Particle Velocimetry system can be a promising optical tool for the measurements of three dimensional particle velocities. One of inherent limitations of particle holography is the very long depth of field of particle images, which causes considerable difficulty in the determination of particle positions in the optical axis. In this study, we introduced three auto-focusing parameters corresponding to the size of particles, namely, Correlation Coefficient, Sharpness Index, and Depth Intensity to determine the focal plane of a particle along the optical axis. To investigate the suitability of the above parameters, the plane image of dot array screens containing different size of dots was recorded by diffused illumination holography and the positions of each dot in the optical axis were evaluated. In addition, the effect of particle position from the holographic film was examined by changing the distance of the screen from the holographic film. All measurement results verified that the evaluated positions using suggested auto-focusing parameters remain within acceptable range of errors. These research results may provide fundamental information for the development of the holographic velocimetry system based on the automatic image processing.

• 한국응용과학기술학회지
• /
• 제29권1호
• /
• pp.63-70
• /
• 2012

자성유체 유체씰에 사용할 수 있는 마그네타이트를 공침법에 의하여 합성하였다. 마그네타이트의 평균입자크기는 동적광산란 측정장치(DLS)에 의해 약 10-12 nm 로 측정되었다. XRD 측정결과, $NH_4OH$ 의 농도가 증가함에 따라 마그네타이트의 결정화도가 증가하였다. 수중 분산된 자성유체의 제타전위는 -49.3 mV 에서 -26.2 mV 까지 DLS에 의하여 측정되었다. 입자의 형상은 구형이었고, 수상과 유상 자성유체에서 스파이킹 효과를 확인하였다.