• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.331-337
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• 2003

This paper represents 50 ㎓ narrow band pass filters for fiber optical communication fabricated by dual ion beam sputtering method. We have analyzed the characteristics of the TA$_2$ $O_{5}$ and $SiO_2$ single layers in order to optimize the process conditions for the 50 ㎓ narrow band pass filters, and controlled the film thickness uniformity to less than 0.1 nm deviation by dual peak spike filter pre-deposition. We designed and fabricated 50 ㎓ narrow band pass filters that consist of 216 layers including 4 cavities based on quarter wave optical thickness. Class substrates with high thermal expansion coefficients were used to reduce the film stress. Anti-reflection coating at the rear side of the substrate was also needed to reduce the optical thickness errors of the Optical Monitoring System caused by multiple beam interference between the front side and the rear side of substrate. The optical characteristics of this 50 ㎓ narrow band pass filters are insertion loss of 0.40 ㏈, pass band ripple of 0.20 ㏈, and pass bandwidth at -0.5 ㏈ of 0.20 nm. and isolation bandwidth at -25 ㏈ of 0.6 nm, which satisfy specifications of dense WDM system in fiber optical communications.tions.

• Radiation Oncology Journal
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• v.25 no.2
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• pp.118-124
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• 2007

[ $\underline{Purpose}$ ]: This study was to evaluate the survival and pattern of failure after radiation therapy of sino-nasal cancer using partial attenuation filer and wedged beams and to help radiotherapy planning of sino-nasal cancer. $\underline{Materials\;and\;Methods}$: Between February 1992 and March 2003, 17 patients with sino-nasal cancers underwent radiation therapy using partial attenuation filter at Dongsan Medical Center, Keimyung university. There were 9 male and 8 female patients. Patients' age ranged from 40 to 75 years (median 59 years). There were 10 patients of maxillary sinus cancer, 7 patiens of nasal cancer. The histologic type was squamous cell carcinoma in 11, adenoid cystic carcinoma in 4 and olfactory neuroblastoma in 2. The distribution of clinical stage by the AJCC system was 3 for stage II, 7 for III and 6 for IV. The five patients were treated with radiation alone and 12 patients were treated with surgery and postoperative radiation therapy. The range of total radiation dose delivered to the primary tumor was from 44 to 76 Gy (median 60 Gy). The follow-up period ranged from 3 to 173 months with median of 78 months. $\underline{Results}$: The overall 2 year survival rate and disease free survival rate was 76.4%. The 5 year and 10 year survival rate were 76.4% and 45.6% and the 5 year and 10 year disease free survival rate was 70.6%. The 5 year disease free survival rate by treatment modality was 91.6% for postoperative radiation group and 20% for radiation alone group, statistical significance was found by treatment modality (p=0.006). There were no differences in survival by pathology and stage. There were local failure in 5 patients (29%) but no distant failure and no severe complication required surgical intervention. $\underline{Conclusion}$: Radiation therapy of sino-nasal cancer using partial attenuation filter was safe and effective. Combined modality with conservative surgery and radiation therapy was more advisable to achieve loco-regional control in sino-nasal cancer. Also we considered high precision radiation therapy with dose escalation and development of multi-modality treatment to improve local control and survival rate in advanced sino-nasal cancer.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.194-195
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• 2002

투명 전도성 박막은 저방출 코팅, 평판디스플레이의 투명전극, 플라즈마 디스플레이 패널(PDP)의 전자파 장해 차폐 둥의 넓은 영역에서 사용되고 있다 특히 PDP의 전자파 장해(electromagnetic interference; EMI)를 막기 위한 필터는 광학적으로 가시광선영역의 높은 투과율과 전도성이 우수한 전기적 특성을 갖고 있어야 한다 이러한 고 효율의 투명전도성 박막은 일반적으로 (산화물-금속-산화물) 형태로 제작된다(1). (중략)

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.11a
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• pp.148-151
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• 2009

본 연구에서는 광섬유를 이용하여 반사형과 투과형의 MR-Compatible Photoplethysmograph (PPG) 측정 시스템을 개발하고, 그 성능을 비교하고자 한다. 반사형 타입은 광섬유 다발의 끝단을 피부에 접촉 시킨 후 반사현상을 이용하여 PPG 신호를 측정하고, 투과형 타입은 광섬유 사이에 피부를 접촉시킨 후 투과현상을 이용하여 PPG 신호를 계측한다. PPG 측정 시스템은 광 신호를 검출하는 센서 부분, 근적외선 광 신호를 송수신하는 광케이블 부분, 신호 증폭 부분, 잡음 제거를 위한 필터부분으로 구성되어 있다. 반사형 및 투과형 PPG 신호의 SNR을 비교한 결과 반사형은 23.5dB이고 투과형은 22.2dB로 차이가 거의 없었다. 그러므로 실험 환경이나 목적에 따라 두 가지 타입 중 효율성이 좀 더 높은 것을 선택하여 사용할 수 있을 것이다.

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.214-215
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.82-83
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• 2003

일반적인 PDP (Plasma display panel)용 전도성 저방출(low-e) 필터는 유리 기판 위에 굴절률이 높은 금속 산화물 유전체 박막과 Ag와 같은 귀금속 박막이 번갈아 쌓인 [유전체｜금속(Ag)｜유전체]가 기본 구조인 다층 박막의 형태로 개발되어 왔다. Ag는 가시광선 영역에서 다른 금속보다 작은 흡수를 보이고 전도성이 뛰어나 전자파 차페용 필터의 전도성 박막으로 널리 쓰인다. 그리고 이러한 구조에서 가시광선의 높은 투과율을 유지하면서 유해 전자기파를 차폐할 수 있도록 충분한 전도성을 갖추기 위해서는 2층 이상의 Ag 박막이 존재하도록 설계되며 유전체 박막과 금속 박막 사이에 1∼2 nm 정도의 매우 얇은 금속 보호 층을 사용한다. (중략)

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.1051-1058
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• 1998

We propose a bandpass filter using wavelength selectivity as variation of writing beam incident angle in photorefractive crystal. From TWM(Two-Wave Mixing) experiment, optimal diffraction properties are induced, and bandpass filter for selection wavelength transmission bandwidth are taken by change of writing beam incident angle.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.647-654
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• 2003

This study investigated the effect of ultrasound on the permeability of the filter paper The investigation involves laboratory experiments, and the laboratory tests were conducted under abroad range of conditions Including energy levels of ultrasonic waves, time for treatment, and temperature. The results of the study show that sonication enhances the permeability of the filter paper significantly. The degree of enhancement varies with sonication power and duration of application. The effect of sonication on permeability with temperature variation and concentration of the test specimens seems not to be significant.

• Polymer(Korea)
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• v.24 no.4
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• pp.453-458
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• 2000

The permeability of oxygen and nitrogen was investigated from the polymeric LB films containing imidazole-metal ion complexes and compared with its corresponding cast films on porous membrane filters. The amphiphilic polymer, poly(N- (2-(4-imidazolyl)ethyl)-maleimide-alt-1-octadecene) (IM-O), was synthesized by reaction of poly(maleic anhydride-alt-1-octadecene) with histamine. The IM-O nonolayer showed high stability on Fe (III) ion-containing subphase. The molecular structure in the LB films was investigated by means of FT-IR spectroscopy. The metal ion concentration incorporated into the LB films was determined by means of XPS measurements. The mechanical stability and uniformity of the LB films on porous substrates were indirectly evidenced by SEM observation. The LB and cast films showed more or less higher selectivity toward nitrogen, and high permeability was found to both the oxygen and nitrogen.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.5
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• pp.465-473
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• 2002

Images are easily corrupted by noise during the data transmission, data capture and data processing. A technical method of noise analyzing and adaptive filtering for reducing of quantum noise in radiography is presented. By adjusting the characteristics of the filter according to local statistics around each pixel of the image as moving windowing, it is possible to suppress noise sufficiently while preserve edge and other significant information required in reading. We have proposed adaptive weighted median(AWM) filters based on local statistics. We show two ways of realizing the AWM filters. One is a simple type of AWM filter, whose weights are given by a simple non-linear function of three local characteristics. The other is the AWM filter which is constructed by homogeneous factor(HF). Homogeneous factor(HF) from the quantum noise models that enables the filter to recognize the local structures of the image is introduced, and an algorithm for determining the HF fitted to the detection systems with various inner statistical properties is proposed. We show by the experimented that the performances of proposed method is superior to these of other filters and models in preserving small details and suppressing the noise at homogeneous region. The proposed algorithms were implemented by visual C++ language on a IBM-PC Pentium 550 for testing purposes, the effects and results of the noise filtering were proposed by comparing with images of the other existing filtering methods.