• 한국광학회지
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• 제6권3호
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• pp.201-213
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• 1995

전자빔여기 XeF$(C\rightarrowA$ 엑시며 레이저의 상준위 B-와 C-상태에 대하여 충동혼합 운동과정을 포함하는 모델을 컴퓨터 시뮬레이션하여 이의 출력특성을 해석하였다 $XeF^*(B)$ 의 수밀도에 관련되는 $XeF^*(C)$의 형성에 대하여 레이저 에너지를 실험치와 비교하였다. 이 결과는 70ns[FWHM]의 전자빔(800kV, 21kA)을 사용한 대기압 매질에서 매우 좋은 일치$(28.5 mJ\pm5%)$를 보였고, $Xe/F_2/Ar=5.26/0.49/94.28%$의 최적화된 가스혼합비를 확인하였다. 또한 시뮬레이션으로 $XeF^*(C)$의 형성경로, $XeF^*(C)$의 완화경로, 청록색 파장대역의 흡수경로에 대한 $F_2$ 할로겐 도우너 및 Xe 압력의 함수관계를 조사하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.221-228
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• 2002

Thickness of concrete lining, voids at the back of lining or shotcrete are very important elements for inspecting the safety of tunnels. Therefore, the inspection of tunnel lining structure means to investigate the inner layer boundaries of the structure. For this purpose, seismic reflection survey is the most desirable method if it works in good conditions. However, the conventional seismic reflection method can not be properly used for investigating thin layers in the lining structure. In other words, to detect the inner boundaries, it is desirable for the wavelength of source to be less than the thickness of each layer and for the receiver to be capable of detecting high frequency(ultrasonic) signals. To this end, new appropriate source and receiver devices should be developed above all for the ultrasonic reflection survey. This paper deals primarily with the development of source and receiver devices which are essential parts of field measuring system. Interests are above all centered in both the radiation pattern, energy, frequency content of the source and the directional sensitivity of the receiver. With these newly devised ones, ultrasonic physical modeling has been performed on 3-D physical model composed of bakelite, water-proof and concrete, The measured seismograms showed a clear separation of wave arrivals reflected from each layer boundary. Furthermore, it is noteworthy that reflection events from the bottom of concrete below water-proof could be also observed. This result demonstrates the usefulness of the both devices that can be applied to benefit the ultrasonic reflection survey. Future research is being focus on dealing with at first an optimal configuration of source and receiver devices well coupled to tunnel wall, and further an efficient data control system of practical use.

• 한국항해항만학회지
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• 제29권5호
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• pp.383-388
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• 2005

레이더 리프렉터를 소형어선, 어망 부이, 어업용 바지선 등에 장착할 경우 최적설치 위치를 결정하기 위한 최적화 시스템의 개발이 필요하다. 최적화 시스템을 개발하기 위한 기본 단계로써 소형어선, 어망 부이, 어업용 바지선 등이 파랑에 의하여 어떠한 응답 특성을 나타내는지 정확하게 파악해야 한다. 본 논문에서는 먼저 해양 부유체식 어업용 바지선 구조물을 대상으로 파랑에 의한 거동을 해석하고자 한다. 어업용 바지선 구조물의 파랑 중 응답특성을 파악하기 위하여 각종 영향인자, 즉 파의 길이, 수심, 입사하는 파의 방향 등이 바지선의 응답에 미치는 영향에 대하여 검토한다. 이러한 응답 특성을 토대로 어업용 레이더 리프렉터를 바지선이나 소형 선박에 설치하였을 경우 파랑에 의한 영향이 레이더 반사 면적에 어떠한 영향을 미치는지를 파악하는 기초자료로 사용하고자 한다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.179-184
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• 2006

Rapid and high-precision positioning with a Global Navigation Satellite System (GNSS) is feasible only when very precise carrier-phase observations can be used. There are two kinds of mathematical models for ambiguity resolution. The first one is based on both pseudorange and carrier phase measurements, and the observation equations are of full rank. The second one is only based on carrier phase measurement, which is a rank-defect model. Though the former is more commonly used, the latter has its own advantage, that is, ambiguity resolution will be freed from the effects of pseudorange multipath. Galileo will be operational. One of the important differences between Galileo and current GPS is that Galileo will provide signals in four frequency bands. With more carrier-phase data available, frequency combinations with long equivalent wavelength can be formed, so Galileo will provide more opportunities for fast and reliable ambiguity resolution than current GPS. This paper tries to investigate phase only fast ambiguity resolution performance with four Galileo frequencies for short baseline. Cascading Ambiguity Resolution (CAR) method with selected optimal frequency combinations and LAMBDA method are used and compared. To validate the resolution, two tests are used and compared. The first one is a ratio test. The second one is lower bound success-rate test. The simulation test results show that, with LAMBDA method, whether with ratio test or lower bound success rate validation criteria, ambiguity can be fixed in several seconds, 8 seconds at most even when 1 sigma of carrier phase noise is 12 mm. While with CAR method, at least about half minute is required even when 1 sigma of carrier phase noise is 3 mm. It shows that LAMBDA method performs obviously better than CAR method.

• Natural Product Sciences
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• 제16권2호
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• pp.116-122
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• 2010

A high-performance liquid chromatography (HPLC) with diode array detector (DAD) and electrospray ionization mass spectrometry (ESI-MS) was established for the simultaneous determination of five representative metabolites of the iridoid and phenolic classes from Rehmannia glutinosa. The optimal chromatographic conditions were obtained on an ODS column (5 mm, $4.6{\times}250\;mm$) with the column temperature at $25^{\circ}C$. The mobile phase was composed of water and acetonitrile using a gradient elution with the flow rate 0.3 mL/min. Detection wavelength was set at 205 nm. All calibration curves showed good linear regression ($r^2$ > 0.997) within test ranges. Limits of detection (LOD) and quantitation (LOQ) values were lower than 0.123 and $0.373\;{\mu}g/mL$, respectively. The developed method provided satisfactory precision and accuracy with overall intra-day and inter-day variations of 0.09 - 0.76% and 0.16 - 1.41%, respectively, and the overall recoveries of 99.03 - 102.67% for all of the compounds analyzed. In addition, effectiveness of diverse extraction methods was compared to each other for the development of standard analytic method. The verified method was successfully applied to the quantitative determination of five representative metabolites in twenty-one commercial Rehmannia glutinosa samples from different markets in Korea and China. The analytical results showed that the contents of the five analytes vary significantly with sources.

• 태양에너지
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• 제11권1호
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• pp.41-49
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• 1991

본 연구에서는 기판의 증착온도를 $200{\pm}5[5^{\circ}C]$로 유지하여 진공증착법으로 (P)SiC/(N)Si 태양전지를 제작하고 그의 특성을 조사하였다. SiC 박막의 최적 두께 $1.2[{\mu}m]$는 박막두께와 변환효율과의 관계로부터 정해졌고 태양전지의 특성은 열치리에 의하여 개선되었다. 최적조건의 열처리 온도와 시간은 $420[^{\circ}C]$에서 12분이고 분광응답의 피크값은 열처리 온도의 증가와 더블어 장파장 쪽으로 이동함을 알았다. X선 회절분석 및 SEM검사는 열처리 온도와 시간에 따라 SiC 박막내에서 결정성장을 보여주며 $2.5{\times}1[cm^2]$의 태양전지에서 최고 변환효율은 11.7[%]이다.

• Journal of the Optical Society of Korea
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• 제17권6호
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• pp.548-558
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• 2013

In this work, laser induced breakdown spectroscopy (LIBS) is used to investigate soil samples collected from different desert areas of Riyadh city in Saudi Arabia. Both qualitative analysis and plasma parameters are studied via the observed LIBS spectra. These experiments have been done using a Spectrolaser-7000 system with 50 mJ fundamental wavelength of Nd:YAG laser and detection delay time of 1 microsecond. Many spectral lines are highly resolved for many elements like Al, Fe, Mg, Si, Mn, Na, Ca and K. The electron temperatures Te and electron densities Ne, for the constituent of generated LIBS plasma, are determined for all the collected samples. It is found that both Te and Ne vary from one desert area to other. This variation is due to the change of the elemental concentration in different desert areas that affects the sample's matrices. Time dependent measurements have also been performed on the soil samples. While the signal-to-base ratio (SBR) reached its optimal value at 1 microsecond, the plasma parameters Ne and Te reach values of $4{\times}10^{17}cm^{-3}$ and 9235 K, respectively, at 2.5 microsecond. The later indicate that the plasma cooling processes are slow in comparison to the previously observed results for metallic samples. The observed results show also that in the future it is possible to enhance the exploitation of LIBS in the remote on-line environmental monitoring application, by following up only the values of Ne and Te for one element of the soil desert sample using an optical fiber probe.

• International Journal of Industrial Entomology and Biomaterials
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• 제35권2호
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• pp.100-105
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• 2017

Under natural conditions, black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae), colonizes in warm temperate regions, and is active in Korea from May through October. Information on black soldier fly rearing, which is affected by seasonal factors in Korea, is limited. Oviposition by black soldier flies is dependent on light intensity and wavelength. Therefore, continuous mass rearing of this fly requires determination of optimal artificial conditions of illumination. In this study, we compared the number of eggs laid under an artificial light source (750 watt HPL lamp) versus nature sunlight. Our results showed that compared to oviposition under natural sunlight, the use of one or two lamps for 7 hours, resulted in only 43 and 76%, of the total number of eggs laid under natural sunlight, respectively. We also investigated the hatchability of oviposited eggs under artificial illumination and under natural sunlight. The hatching rate under the former was much significantly lower than under the latter. Further detailed research is required to develop methods for successful mass rearing of black soldier fly throughout the year by means of an indoor system.

• 한국세라믹학회지
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• 제56권1호
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• pp.98-103
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• 2019

Optical filters to control light wavelength of displays or cameras are fabricated by multi-layer stacking process of low and high index thin films. The process of multi-layer stacking of thin films has received much attention as an optimal process for effective manufacturing in the optical filter industry. However, multi-layer processing has disadvantages of complicated thin film process, and difficulty of precise control of film morphology and material selection, all of which are critical for transmittance and coloring effect on filters. In this study, the composite $TiO_2$, which can be used to control of UV absorption, coated on nano hollow silica sol, was synthesized as a coating material for optical filters. Furthermore, systematic analysis of the process parameters during the chemical reaction, and of the structural properties of the coating solutions was performed using SEM, TEM, XRD and photo spectrometry. From the structural analysis, we found that the 85 nm nano hollow silica with 2.5 nm $TiO_2$ shell formation was successfully synthesized at proper pH control and titanium butoxide content. Photo luminescence characteristics, excited by UV irradiation, show that stable absorption of 350 nm-light, correlated with a 3.54 eV band gap, existed for the $TiO_2$ shell-nano hollow silica reacted with 8.8 mole titanium butoxide solution. Transmittance observed on substrate of the $TiO_2$ shell-nano hollow silica showed effective absorption of 200-300 nm UV light without deterioration of visible light transparency.

• 한국동물위생학회지
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• 제43권4호
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• pp.261-265
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• 2020

Each commercial cyromazine insecticide has different HPLC conditions. The aim of this study was to establish a standardized chromatographic method for the determination of cyromazine in commercial insecticides. The separation was achieved on two C18 columns - Waters® Bondapak C (4×300 nm i.d., 10 ㎛) and X bridge (4.6×250 nm i.d., 5 ㎛) using a mobile phase composed of water/methanol/ethanolamine (76:24:0.1, v/v), with UV detection at wavelengths 230 nm and 254 nm. A total of six commercial cyromazine insecticides were analyzed. In this study, the optimal high-performance liquid chromatography conditions for the analysis of cyromazine were as follows: a mobile phase of water/methanol/ethanolamine (76:24:0.1, v/v) at a flow rate of 1.0 mL/min and a detection wavelength of 230 nm using a X bridge C18 column (4.6×250 nm i.d., 5 ㎛) at a column temperature of 25℃. The calibration curve was linear in the concentration range of 5~50 ㎍/mL, with a correlation coefficient of 0.99995. The cyromazine detection limit was 0.2 ㎍/mL, and the limit of quantification was 0.59 ㎍/mL. The percentage recovery ranged from 99.8% to 101.0% for cyromazine, and the relative standard deviation was not over 2.0%. The cyromazine concentration ranged from 92.7% to 109.4% and was within the acceptable range (90~120%) for the percent of the labeled amount. This method was found to be suitable for determining cyromazine in commercial insecticides.