• 한국정보통신학회논문지
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• 제12권7호
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• pp.1249-1255
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• 2008

1530nm 파장 대역이 L밴드 (long-wavelength-band) EDFA(erbium-doped fiber amplifler)를 위한 펌프 파장으로 연구되었다. 이 펌프 광원은 파장 가변 광원과 직렬 연결된 C 밴드 (conventional-band) EDFA로 제작되었다. 이 L밴드 EDFA는 순방향 펌핑 구조를 사용하였다. 1530nm 대역 내에서 1545nm 펌프 파장을 사용하였을 때 0.454B/mW 이득 계수를 얻었는데 이는 기존에 사용되는 1480nm 파장으로 펌핑 하였을 경우보다 2배 이상 높은 수치이다. 1530nm 파장 펌핑의 잡음지수는 가장 좋지 않은 경우가 6.36dB였는데 이는 1480nm 펌핑보다 0.75dB 높은 값이다. 제안된 펌핑 파장을 이용하는 L밴드 EDFA에서 얻은 이 같은 골은 이득 계수는 이 L밴드 EDFA가 전력 소모를 적게 한다는 것을 의미한다.

• 한국기계기술학회지
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• 제20권6호
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• pp.770-775
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• 2018

In this study, the characteristics of muscle relaxation were analyzed by the experimental and numerical method. A skin tissue was produced by imitational biological tissue using the agar powder, saline solution and sugar. The tissue was exposed to three types of wavelength-blue visible radiation(410 nm), red visible radiation(635 nm), and infrared ray(830 nm). The temperature results along the depth of tissue were measured according to the variation of light wavelength and irradiation time. The temperature change of the tissue shown up similar pattern regardless of the light wavelength kinds. The wavelength of infrared ray penetrated strongly into tissue between 3.2 mm and 11.4 mm. Also, the temperature change with the irradiation time was small, and the temperature value of the infrared ray was the largest. As a result, the muscle relaxation will occur mainly at the infrared wavelength.

• Advances in nano research
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• 제13권5호
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• pp.475-485
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• 2022

Crystalline silicon photovoltaic cells have advantages of zero pollution, large scale and high reliability. A major challenge is that sunlight wavelength with photon energy lower than semiconductor band gap is converted into heat and increase its temperature and reduce its conversion efficiency. Traditional cooling PV method is using water flowing below the modules to cool down PV temperature. In this paper, the idea is proposed to reduce the temperature of the module and improve the energy conversion efficiency of the module through the modulation of the solar spectrum. A spectrally selective nanofilm reflector located directly on the surface of PV is designed, which can reflect sunlight wavelength with low photon energy, and even enhance absorption of sunlight wavelength with high photon energy. The results indicate that nanofilm reflector can reduce spectral reflectivity integral from 9.0% to 6.93% in 400~1100 nm wavelength range, and improve spectral reflectivity integral from 23.1% to 78.34% in long wavelength range. The nanofilm reflector can reduce temperature of PV by 4.51℃ and relatively improved energy conversion efficiency of PV by 1.25% when solar irradiance is 1000 W/m². Furthermore, the nanofilm reflector is insensitive in sunlight's angle and polarization state, and be suitable for high irradiance environment.

• 한국광학회지
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• 제1권2호
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• pp.155-161
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• 1990

메틸알코올 레이저의 여기용으로 저속축류형의 가변파장 $CO_2$ 레이저를 제작하였다. 파장가변은 ZnSe Brewster 창과 반사 회절격자를 사용하였으며, 반사 회절격자는 Blaze wavelength 10.6$\mu\textrm{m}$, 100grooves/mm 인 평면형이다. 실험은 $CO_2$ 레이저의 연속발진 출력특을 살펴보고, $CO_2$ 레이저의 전 발진구간을 파장가변시켜 얻어진 출력분포를 $CO_2$ 레이저의 이득 곡선과 비교하였다. 연속발진 출력은 기체 혼합비 $CO_2: N_2$ : He=1:3:10, 전류 55mA, 압력 14 torr 일 때 100W를 얻었다. 가변된 파장은 10.4$\mu\textrm{m}$ 영역의 R(6)-R(38), P(6)-P(36), 9.4$\mu\textrm{m}$ 영역의 R (10)-R(32), P(10)-P(38)의 약 60여개의 회전선이 발진함을 확인하였고, 이 때의 파장은 9.3295$\mu\textrm{m}$에서 10.7648$\mu\textrm{m}$까지 변화하였다. 각 영역에서 얻어진 출력분포는 $CO_2$ 레이저의 이득곡선과 잘 일치하였고, 최대 출력은 20W 정도였다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.315-316
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• 2014

Combustion gases emit various radiation signals by chemical reaction and excited molecules in combustion system. Since temperature measurement of combustion system is very difficult, non-contact temperature measuring methods are being researched. In this paper, we propose optical system of simple structure and implement technique for measuring temperature partially in furnace using radiation wavelength signals of high temperature $CO_2$ gas generated during combustion.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.309-310
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• 2003

We have designed novel transreflective liquid crystal displays which utilize dielectric mirrors. The reflective and transmissive modes are operated in different wavelength regions. The displays have the advantages: (1) the brightness as a function of applied voltage is the same for both modes, (2) the backlight and ambient light are utilized efficiently.

• 천문학회지
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• 제29권spc1호
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• pp.337-338
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• 1996

The long quasi-periodic (several tens of seconds) pulsations were observed at. short decimetric wavelength (1.42 and 2.00 GHz). Here, we introduce the features (about bandwidth, periodicity, amplitude and relative amplitude) of these pulsations, then give the discussion about them.

• 수산해양기술연구
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• 제51권2호
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• pp.179-187
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• 2015

Experiments designed to measure the effect of LED (light-emitting diode) light wavelength on the growth of fingerling rockfishes (Sebastes inermis) were conducted. Fingerling rockfishes (average body weight of individual: 1.13g) were divided into two groups by wavelength of the LED light [light power: 1,620 mW; wavelength: 518 nm (green color), 622 nm (red color)]. Triplicate groups of 180 individuals were reared over 7 weeks. Lighting duration was 14 hours from 06:00 to 20:00. A water tank exposed on the natural light in a room through the windows was used as a control. At results of the first experiment [initial average body weight (BW) of individual: 1.13 g; standard deviation (SD): 0.13 g], the final individual BW exposed on the green color was increased 0.39 g than the red color, and decreased 0.12 g than the natural light in the room. At results of the second (initial individual BW: 5.07 g; SD: 0.70 g) and the third experiment (initial individual BW: 10.67 g; SD: 0.67 g), the final individual BW exposed on the green color was increased 1.07 g and 2.55 g than the red color, respectively, and increased 0.57 g and 0.84 g than the natural light, respectively. The relative growth rate of the green color was higher about 8% significantly (p<0.05) than the natural light. In the case of the red color the relative growth rate was lower significantly (p<0.05) than the natural light.

• 에너지공학
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• 제23권1호
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• pp.1-6
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• 2014

본 에너지 분산 형 미세열량측정에 관한 자료는 에너지 분산 형의 우수한 조작 성을 유지하면서 파장 분산 형과 비슷한 정도의 에너지 분해능을 가질 수 있도록 개선한 것으로 광범위한 에너지의 X선을 검출을 할 수 있다. X선을 검출하기 위해서 이용되는 파장 분산 형은 에너지 분해능이 우수하지만 X선의 파장에 대해 검출 각도를 변화시켜야 하고 검출하고자 하는 특정 X선 종류에 따라 몇 가지의 검출기를 필요로 하고 있다. 그러나 에너지 분산 형의 검출기는 한 개의 검출기로 광범위한 X선을 동시에 검출할 수 있으며 조작 방법도 비교적 용이하다. 그러나 에너지 분산 형은 에너지 분해능이 우수하지 못 하고 또한 인접한 에너지를 갖는 X선은 그 피크가 중첩되어 구별하기가 어려운 경우도 있다. 에너지 분해능은 파장분산 형이 2~20 eV이고 에너지 분산 형은 140~180 eV로 상당한 차이가 있다.

• Journal of Advanced Marine Engineering and Technology
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• 제33권2호
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• pp.330-335
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• 2009

A fiber-optic liquid level sensor based on bending cantilever beam has been proposed. A fiber Bragg grating(FBG) embedded in the cantilever beam is used to sensing elements. The basic concept is elongation and constriction of the FBG corresponding to the liquid level variation. The best FBG position on the cantilever for obtaining the high sensitivity was 4 cm from the fixing point. When the liquid level moves up and down vertically, the Bragg wavelength is linearly shifted. But, the wavelength sensitivity of the FBG installed on the upper side of cantilever was four times better than that of the FBG equipped in the lateral side due to the difference of unit strain applied to the FBG. Intensity demodulation using the low-cost edge filter is used to interrogate the Bragg wavelength through converting the wavelength signals into the optical intensity ones. Experiment results show that the electrical output is exponentially proportional to the liquid level. But, it should be overcome for applying to the ships.