• Korean Journal of Head & Neck Oncology
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• v.17 no.1
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• pp.3-7
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• 2001

Objectives: New photosensitizer 9-hydroxypheophorbide-$\alpha$(9-HpbD-$\alpha$) was derived from chlorophyll in water with peak absorption at 660nm. 9-HpbD-$\alpha$ was tested with 660 nm diode laser for the anticancer effect of photodynamic therapy. Materials and Methods: Human SNU 1041 cells were seeded into 96 well plate at a density of $$ cells/well for 24 hours. Cells were washed with media containing various concentration of 9-HpbD-$\alpha$ ranging from $0{\mu}g/ml\;to\;3.75{\mu}g/ml$. Then, laser treatment was done with 660nm diode laser ($10mW/cm^2$) at various time setting (0, 30, 60, 90, 120 minutes) and with various time interval (0, 1, 4, 6, 18 hours). The treated cells were incubated 48 hours and MTT assay was done to measure the viability of cells. Results: The viability of cells was more than 90% after laser treatment in control group. The viability of cells was decreased with increasing concentration of 9-HpbD-$\alpha$ and laser treatment time in experimental groups. The viability of cells was decreased significantly as the interval time between addition of 9-HpbD-$\alpha$ and laser irradiation was increased. Conclusion: This study shows the anticancer effect of photodynamic therapy using 9-HpbD-$\alpha$ and 660nm Diode laser on carcinoma cell line. 9-HpbD-$\alpha$ is considerd as one of new photo sensitizers in the field of photodynamic therapy.

• Investigative and Clinical Urology
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• v.59 no.6
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• pp.392-398
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• 2018

Purpose: To evaluate the initial experience and outcome of photo-selective vaporization of the prostate (PVP) for benign prostatic hyperplasia (BPH) in Pakistan with the use of a 980 nm diode laser. Materials and Methods: A prospective study was performed from November 2016 to December 2017. A total of 100 patients diagnosed with bladder outlet obstruction secondary to BPH who planned for PVP were enrolled in the study. PVP was carried out with a diode laser at 980 nm (Biolitec Diode 180W laser) in a continuous wave with a 600 nm (twister) fiber. Baseline characteristics and perioperative data were compared. Postoperative outcomes were evaluated by International Prostate Symptom Score (IPSS), post void residual (PVR) and maximum urinary flow rate (Qmax) at 3 and 6 months after surgery. Results: The mean age was $65.82{\pm}10.42$, mean prostate size was $67.35{\pm}16.42$, operative time was $55.85{\pm}18.01$ and total energy was $198.68{\pm}49.12kJ$. At 3 months and 6 months, significant improvements were noted (p<0.001) in IPSS $7.04{\pm}1.69$ (-18.92), Qmax $19.22{\pm}4.75mL/s$ (+13.09) and and PVR $18.89{\pm}5.39mL$ (-112.80). Most frequent problems were burning micturition (35%) and terminal dysuria (29%). No significant difference in postoperative hemoglobin was seen in patients who were on anti-platelet drugs. Conclusions: PVP with a diode laser is a safe and effective procedure for the treatment of BPH and is also safe in patients who are on anti-platelet agents.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.79-85
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• 2016

Recently, visible light communication(VLC) is being actively researched as green wireless communication services are drawing attention. Currently, VLC mostly uses LED for transmission and PD(Photo Diode) for receiving. However, this kind of system has limited applications. Therefore, we design and propose in this paper, a LED-to-LED two way VLC system that doesn't use PD(Photo Diode). This system has the following features and contributions. First, this system uses just LED at both transmitter and receiver with analog switch, Second, this system support both one-way communication and two way communication together. One way communication can support multi-hop communication. The performance evaluation of the proposed system is conducted at a place with standard light. We test the success or failure of one way communication by changing distance and baud rate while test the success and failure of two way communication by changing distance. We expect that the proposed LED-to-LED system in this paper can be applied for various application fields.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.4
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• pp.130-135
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• 1999

The main scale of linear encoder greatly effects on the precision of displacement measurement. Especially when needing the long range measurement the length of main scale should be increased accordingly. In this paper we propose a linear encoder that uses laser interference pattern as main scale for long range measurement. The linear encoder is similar to Michelson interferometer excepting that the reference mirror is tilted so as to obtain interference fringe pattern and a grating panel is attached on a quadratic photo diodes. Four kinds of grating having phase difference of 0. $\pi$/4, $\pi$/2, 3$\pi$/4 are arranged on the panel. The experimental results show that signals of quadratic photo diode A, B, {{{{ {-}atop {A } }}}} and {{{{ {- } atop {B } }}}} are cosine wavelike and successive signals have phase difference of $\pi$/4 each other. So the proposed method can achieve improved measurement resolution.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.281-284
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• 2004

Photo-induced memory effect of an organic light-emitting diode(OLED) composed of a hydrazone-derivative(DBAH) dispersed in bis-phenol-A type polycarbonate polymer(PCA) in the presence of thio-Michler's ketone, was investigated by the measuring of the current density and luminance at the various conditions. After the light exposure, the current of the OLED was decreased approximately one order, and the luminance of the OLED also decresed. This memory effct was erasable by heating the OLED to the temperature higher than the glass transition temperature(Tg). As shown in this result, we found the memory effect was erased by heating and returned to its original state in the hole injecting layer(HIL) of the OLED. A series of these phenomena was suggested the possibility of the application to the imaging plate.

• Electrical & Electronic Materials
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• v.7 no.6
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• pp.549-556
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• 1994

광전변화소자(Photo electric conversion device)는 광전효과-내부 광전효과(광도전 및 광기전력) 및 외부광전효과(광전자방출)을 이용하여 광을 전기신호로 변화시키는 소자를 광전자소자라 하며, 광전자 및 양자전자공학의 발전과 함께 많은 개발이 되고 있다. 이 광전변환소자는 주로서 고체박막의 재료를 이용하며, 소자의 소형화, 고성능화, 고신뢰성등의 요구와 함께 광전기술연구가 활발하게 진행되고 있다. 현재 광전소자의 광의 파장은 가시부만이 아니고, X선으로 부터 적외선까지에 걸쳐 있다. 이 파장에 대응하여 각종의 단결정이 필요하고, 소자의 설계가 요구된다. 이들의 응용은 소자의 광의 발진, 증폭, 검출의 소자만이 아니고 변조, 편향, 기록, 전달로등 다종다양의 기능을 갖는 소자가 요구되고 있다. 이들의 Optoelectronic Device의 연구가 활발하게 진행되어 새로운 광전소자의 제품이 개발되고 있어, 이에 대한 소개를 하고져 한다.

• Laser Solutions
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• v.2 no.1
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• pp.30-37
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• 1999

Laser-welded Tailored Blank is the hottest thing in many automobile companies. But they demand on weld quality, reproducibility, and formability. So it is the great problem of automation of laser welding process. Therefore, it is requested to construct on-line process monitoring system on high accuracy. The light which is emitted from plasma and spatter in laser welding was detected by photo-diodes. It was found that the light intensity depends on welding speed. laser power, and flow rate of assist gas. The relationship between the plasma and spatter and the weld quality can be used for on-line laser weld monitoring systems.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.9
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• pp.72-77
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• 1994

GaAs MISFETs, with photo-CVD grown P$_{3}$N$_{5}$ gate insulator and sulfide treatment, have been fabricated and showed the instability of drain current reduced less than 22 percent for the period of 1.0s~1.0${\times}10^{4}s$. The effective electron mobility and extrinsic transconductance of the device are about 1300cm$^{2}$/V.sec and 1.33mS at room temperature. The C-V characteristics of GaAs MIS Diode and AES analysis are also discussed with respect to effect of sulfide treatment conditions.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.10
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• pp.203-208
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• 1999

By tilting the reference mirror of Twynman-Green interferometer having a reference mirror and a moving mirror, firinge pattern composed of bright and dark parallel lines can be obtained and the fringe pattern is shifted according to the displacement of the mowing mirror. Several studies are executed for displacement measurement by detecting the intensity of the fringe with photo-diodes having small detecting area. In this study, to improve the sensitivity and robustness, the intensity of fringe is detected by using a large-area quadratic photo-diode masked with a grating panel having four kinds of binary grating having phase-difference of 0, {\pi}$/4, {\pi}$/2, 3 {\pi}$/4. The phase of the fringe is calculated with a simple 4-buckets algorithm. A experimental result shows that standard deviation of 5.653 nm is obtained comparing with a capacitive type gap sensor having nearly 1 nm accuracy.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.170-174
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• 1999

The main scale of linear scale greatly affects on the precision of displacement measurement. Especially when needing the long range measurement, the length of main scale should be increased accordingly. In this paper, we propose a linear scale that uses laser interference pattern as main scale for long range measurement. The linear scale is similar to Michelson interferometer excepting that the reference mirror is tilted so as to obtain interference fringe pattern and a grating panel is attached on a quadratic photo diodes. Four kinds of grating having phase differences of 0, $\pi$ /4, $\pi$ /2, 3 $\pi$ /4 are arranged on the panel. The experimental results show that signals of - quadratic photo diode, A, B,$\overline{A}$ and $\overline{B}$ are cosine wavelike and successive signals have phase difference of $\pi$/4 each other. So the proposed method can achieve improved measurement resolution.