• Bulletin of the Korean Chemical Society
• /
• 제27권5호
• /
• pp.725-732
• /
• 2006

A rapid flotation methodology for zinc(II) separation and enrichment from human biofluids is established. At pH 6.0 and ambient temperature, using oleic acid (HOL) as a foaming reagent, zinc(II) was separated with phenanthraquinone monophenyl thiosemicarbazone (PPT) as a new flotation collector for Zn(II). The floated red colored 1 : 2 Zn(II)-PPT complex was measured spectrophotometrically at 526 nm with a molar absorptivity of $1.83 \;{\times}\; 10^5\; L$ mol $L ^{-1}\;cm ^{-1}$. Beer's law was obeyed over a concentration range 0.05-1.0 mg $L ^{-1}$ in the aqueous as well as in the scum layers. The proposed preconcentration flotation methodology was applied to determine Zn(II) in human biofluids. Application was, also, extended to determine Zn(II) in pharmaceutical samples and natural water samples spiked with known amounts of Zn(II) with a preconcentration factor of 100 and a detection limit of 10 ng m$L ^{-1}$. The method was verified by comparison of the spectrophotometric results with flame atomic absorption spectrometric (AAS) measurements. Moreover a postulation for the mechanism of flotation is proposed.

• Journal of Welding and Joining
• /
• 제27권5호
• /
• pp.62-67
• /
• 2009

Welding deformation during the assembly process is affected by not only local shrinkage due to rapid heating and cooling, but also root gap and misalignment between parts to be welded. Therefore, the prediction and control of welding deformation have become of critical importance. In this study, it was focused on the development of the 3-axis apparatus for real-time measurement of the welded deformation. To achieve the objective, a D-H algorithm has been carried out to check the behavioral and performance evaluation for the developed robot. The sequence experiments were taken the base materials of $400{\times}200{\times}4.5mm$ plate for butt welding. The real-time experimental measurements are in good agreement with the measured results.

• 대한전자공학회논문지TC
• /
• 제37권10호
• /
• pp.1-8
• /
• 2000

본 연구에서는 AOA(Angle of Arrival)와 TOA(Time of Arrival) 그리고 TDOA(Time Difference of Arrival)의 추정값을 이용한 위치 추정 기법들을 설명하고 분석하였다 이들 기법들을 다중경로 페이딩 (mutipath fading)과 shadowing을 갖는 마이크로셀 환경에 적용한다면, 빠르고 예측할 수 없는 신호 레벨 의 변화로 인하여 이동체의 위치를 정확히 추정하는 것은 어렵다. 따라서 본 연구에서는 수신 신호 세기 (RSS: Received Signal Strength) 이외에 이동체와 기지국간의 거리, 이동체의 이동방향, 이동체의 이전위치와 같은 부정확한 다수의 파라미터를 동시에 고려하는 퍼지 다기준(multi-criteria) 의사 결정 방법을 이용하여 이동체의 위치를 결정하는 방법을 제안한다. 시뮬레이션을 통하여, 이동체의 방향과 속도의 영향을 분석한다.

• 한국수자원학회논문집
• /
• 제37권7호
• /
• pp.517-526
• /
• 2004

농업용수는 국가의 수자원 관리에서 매우 중요한 부분이다. 관개회귀수는 농지에 관개한 수량 중에서 다시 하천으로 회귀되는 양이며 관개회귀수량을 정확하게 추정하는 것은 수자원 개발 계획과 관리에 있어서 매우 중요하다. 본 연구는 낙동강유역 내의 소규모 논지대에 조사지구를 선정하여 2003년도 영농기간 동안 농업용수 공급량과 배수량을 조사 분석하여 회귀율을 산출하고, 이를 향후 수자원계획의 기초자료로 활용하기 위하여 수행하였다. 조사대상 지구인 경북 청도 녹명지구의 관개기간 중 신속회귀율은 30.2%, 지연 회귀율은 23.5%로 전체 회귀율은 53.7%로 나타났다.

• 한국세라믹학회지
• /
• 제47권3호
• /
• pp.210-215
• /
• 2010

In this study, an expanded graphite-titanium oxide composite is developed from expanded graphite (EG) and titanium n-butoxide (TNB). EG is synthesized by chemical intercalation of natural graphite (NG) and rapid expansion at high temperature. TNB is used as the titanium source. The performances of the prepared EG-$TiO_2$ composite are characterized by BET surface area measurements, scan electron microscope (SEM), X-ray diffraction patterns (XRD) and energy dispersive X-ray analysis (EDX). The catalytic activities of the EG-$TiO_2$ composite are investigated by analysis of the degradation of methylene blue (MB) in aqueous solution under irradiation of UV light. Compared with the pristine $TiO_2$ and activity carbon-$TiO_2$ (AC-$TiO_2$) composite, the EG-$TiO_2$ composite shows very high efficiency against MB solution, and the EG could improve the photocatalytic effect of $TiO_2$ in the MB degradation reaction under the irradiation of UV light.

• 한국산업정보학회논문지
• /
• 제7권5호
• /
• pp.190-194
• /
• 2002

본 연구의 최종 개발목표는 편리하고 값싸고, 신뢰도 있고, 성능 좋은 컴퓨터 자동 소음차폐성능 측정기의 개발에 있다. 자동차 및 건축물의 안락한 환경은 현대의 필수 불가결한 요건이다. 본 논문은 자동차용 바킹류 및 방음고무에 의한 소음차폐의 성능 측정을 향상시키는 부분에 중점을 두었다. Sound Card를 이용하여 손쉽게 음성을 획득 할 수 있도록 하였으며 음향실과 측정실의 음성 획득을 한 방향으로만 하여 회로의 복잡성을 줄였다. 개발된 최종 시스템은 개발 시판되고 있는 시스템보다 측정방법이 간편하고 빠른 기계적 응답성을 갖추고 있다. 짧은 시간 안에 전체적인 주파수별 소음차폐성능을 달수 있도록 "대강보기" 항목도 첨가하여 각종 건축 및 고무 제품의 차폐성능 검사를 효율적으로 할 수 있도록 하였다.

• Asian Journal of Atmospheric Environment
• /
• 제10권1호
• /
• pp.42-50
• /
• 2016

This study presents a performance evaluation of four different land surface models (LSM) available in Weather Forecast Research (WRF). The research site was located in Haean Basin in South Korea. The basin is very unique by its geomorphology and topography. For a better representation of the complex terrain in the mesoscale model were used a high resolution topography data with a spatial resolution of 30 meters. Additionally, land-use layer was corrected by ground mapping data-sets. The observation equipments used in the study were an ultrasonic anemometer with a gas analyzer, an automatic weather station and a tethered balloon sonde. The model simulation covers a four-day period during autumn. The result shows significant impact of LSM on meteorological simulation. The best agreement between observation and simulation was found in the case of WRF with Noah LSM (WRF-Noah). The WRF with Rapid Update Cycle LSM (WRF-RUC) has a very good agreement with temperature profiles due to successfully predicted fog which appeared during measurements and affected the radiation budget at the basin floor. The WRF with Pleim and Xiu LSM (WRF-PX) and WRF with Thermal Diffusion LSM (WRF-TD) performed insufficiently for simulation of heat fluxes. Both overestimated the sensible and underestimated the latent heat fluxes during the daytime.

• ALGAE
• /
• 제20권2호
• /
• pp.157-166
• /
• 2005

Uptake kinetics of Cd and Zn by leaves and rhizome of the seagrass Zostera marina were examined in controlled laboratory radiotracer experiments. Subsequently, acute toxicity of Cd, Cu and TBT on photosynthetic quantum yield (ΔF/Fm’ of Z. marina were determined, and the differential sensitivities of rapid light curve (RLC) to those harmful substances were also compared. All measurements on photosynthetic activity were determined by chlorophyll a fluorescence method using pulse amplitude modulation (PAM). Metal uptake by Z. marina was saturated with increasing exposure time in leaves and rhizomes. Uptake of Zn by Z. marina was faster than that of Cd. Metal uptake rates in Z. marina decreased with the increase of dissolved metal concentrations and also with the increase of biomass. The adverse effect of TBT on effective quantum yield was stronger than other pollutants. Average acute toxicity on the RLC of the seagrass exposed to TBT and two heavy metals (Cd and Cu) was going to decrease as follows: TBT > Cd > Cu. Our preliminary results in this study suggested that Z. marina potentially can be used as a biomonitor of harmful substances contamination in coastal waters.

• 한국수자원학회논문집
• /
• 제34권1호
• /
• pp.91-103
• /
• 2001

본 연구에서는 지표면유출과 하천유출의 실시간 연계를 통하여 하천 각 구간에서의 수위와 유량을 예측하는 수리학적 홍수추적 모형을 개발하였다. 주로 유역의 지형특성에 따라 결정되는 수문곡선의 형상을 반영하여 홍수 유출량 산정방법을 개선하였으며, 침투과정을 고려하여 강우초가 첨두유량의 과다산정을 제거하였다. 지표면유출의 하천유입을 연속방정식에 반영하여 여러 단면에서의 유입이 용이하였으며, 이는 강우의 급격한 변이에서도 수치적 안정을 가져다 주었다. 폭우시 양양 남대천 유역에서 현장 관측을 실시하였으며, 관측자료에 적용하여 개발된 모형의 현장 적용성과 신뢰성을 확보하였다.

• 기술사
• /
• 제15권1호
• /
• pp.46-50
• /
• 1982

Following rapid industrial development and urbanization in Korea, there is a need for the Government to implement effective control of pollution and to undertake specific schemes in areas where pollution of the environment is severe. In response to this need, Government of Korea prepare Han River Basin Environmental Master Plan Project for water, air, solid waste to cover environmental protection of the Han River Basin. The Project area is approximately 27,000 sq. Km extending over Seoul, Kyunggi, Kwangwon, Chungbuk Province. The total population of Master Plan Project area is approximately 11.6 million, or one-third of the total population of Korea. There are about 8,000 industries, including those located in 16 industrial complexes, in the project area. The scope of work and terms of reference are the following: (1) A Summary of existing land use and forecasts for changes in land use by the year 2,000. (2) Emission inventories for air, waste water, and solid wastes. (3) Forecasts of future population growth patterns and pollution loadings. (4) Identification of specific projects needs to reduce pollution levels and satisfy the environmental quality standards. (5) A Program of enforcement to include (i) self monitoring, and (ii) governmental inspections and surveillance. (6) A program for quality improvement and quality assurance of environmental measurements. (7) Reports summarizing all data collected analyzed during the study. (8) Conceptual design and feasibility studies, including cost estimates, for needed pollution control projects. (9) A financial plan for future detailed design and construction of public facilities, for financial incentives to industry, and for user charges for industrial use of public treatment of disposal works.