• 한국입자에어로졸학회지
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• 제9권1호
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• pp.7-21
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• 2013

Twelve-hour size-resolved atmospheric aerosols were measured to determine size distributions of water-soluble organic carbon(WSOC) during daytime and nighttime, and to investigate sources and formation pathways of WSOC in individual particle size classes. Mass, WSOC, ${NO_3}^-$, $K^+$, and $Cl^-$ at day and night showed mostly bimodal size distributions, peaking at the size range of $0.32-0.55{\mu}m$(condensation mode) and $3.1-6.2{\mu}m$(coarse mode), respectively, with a predominant condensation mode and a minor coarse mode. While ${NH_4}^+$ and ${SO_4}^{2-}$ showed unimodal size distributions which peaked between 0.32 and $0.55{\mu}m$. WSOC was enriched into nuclei mode particles(< $0.1{\mu}m$) based on the WSOC-to-mass and WSOC-to-water soluble species ratios. The sources and formation mechanisms of WSOC were inferred in reference to the size distribution characteristics of inorganic species(${SO_4}^{2-}$, ${NO_3}^-$, $K^+$, $Ca^{2+}$, $Na^+$, and $Cl^-$) and carbon monoxide. Nuclei mode WSOC was likely associated with primary combustion sources during daytime and nighttime. Among significant sources contributing to the condensation mode WSOC were homogeneous gas-phase oxidation of VOCs, primary combustion emissions, and fresh(or slightly aged) biomass burning aerosols. The droplet mode WSOC could be attributed to aqueous oxidation of VOCs in clouds, cloud-processed biomass burning aerosols, and small contributions from primary combustion sources. From the correlations between WSOC and soil-related particles, and between WSOC and sea-salt particles, it is suggested that the coarse mode WSOC during daytime is likely to condense on the soil-related particles($K^+$ and $Ca^{2+}$), while the WSOC in the coarse fraction during nighttime is likely associated with the sea-salt particles($Na^+$).

• Archives of Pharmacal Research
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• 제29권6호
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• pp.514-519
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• 2006

A simple HPLC method using UV detection was developed and validated for the determination of levodropropizine (LDP) In dog plasma. The sample was prepared for injection using a liquid-liquid extraction method with 1-phenypiperazine as the internal standard. The mobile phase was methanol - diethylamine solution (0.05 M) (20:80, v/v, pH adjusted to 3.0 with $H_3PO_4$) with a detection wavelength of 240 nm. The limit of quantitation (LOQ) of LDP in a biological matrix was determined to be 25.25 ng/mL. The calibration curve was linear across the concentration range of 25.25 to 2020 ng/mL. The intra-day and inter-day precision values (CV%) were within 7% and accuracy (R.E. %) was within 6% of the nominal values for medium (252.5 ng/mL) and high (2020 ng/mL) LDP concentrations. For the LDP concentration at the LOQ, the intra-day and inter-day precision and accuracy were within 20% and 10%, respectively. The average absolute recovery for LDP was 70.28%. This method was successfully used to analyze plasma samples in a steady-state bioavailability study of a newly developed sustained-release LDP tablets (SR) using immediate-release tablets (IR) as the reference. The relative bioavailability of the SR was determined to be $106.3\;{\pm}\;12.8%$ (n=6). The $C_{max}$ of the SR was significantly lower (p<0.05), and the $t_{max}$ was significantly longer than that of the IR (p<0.05). The results of ANOVA and two one-sided tests indicated that the SR exhibited acceptable sustained release properties and was bioequivalent to the IR.

• 한국통신학회논문지
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• 제33권3A호
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• pp.327-334
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• 2008

동일 채널 중계기에서는 송 수신 신호간의 간섭으로 인해 중계기의 출력이 제한되는 문제점이 있다. 이러한 문제를 해결하기 위해 중계기에서 수신 신호를 복조하여 궤환채널을 추정하고 궤환신호를 제거하는 방법이 제시되었으나, T-DMB 시스템과 같이 파일럿 간격이 넓은 시스템에 복조형 궤환신호 제거방법을 적용할 경우 궤환채널 추정 속도가 느리다는 단점이 있다. 이를 극복하기 위해 본 논문에서는 시간영역의 파일럿을 여러 개의 서브 그룹으로 분할하여 궤환채널을 추정함으로써 적응 필터의 갱신 횟수를 증가시킬 수 있는 방법을 제안한다. 제안된 방법은 궤환채널 추정 속도를 개선하여 궁극적으로 궤환신호 제거 성능을 향상시킨다. 모의실험을 통해 제안된 방법이 기존 방법에 비해 궤환채널 추정 속도와 잔류 궤환신호 전력 (RFP) 측면에서 우수함을 보인다.

• 한국조경학회지
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• 제13권2호
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• pp.13-26
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• 1985

^x The enviroment defines the living conditions for people and has at the same time the possibility to create new environment. In Korea, where the rate of urbanization reached more than 50% in 1970′s the priority has been put on the economic development and administrative function. Under the circumstance, visual environmental field was dealt lightly and it resulted in undesirable environment. The techniques of Mordern Arts (Montage, Depeysment, Tromp L′oeil, P.O.P Art, etc.) helped Super Graphics appear in the urban areas. Environmental Art has been expended into the public space and people came to recognize the Arts as the "Street Art" or "Street as Gallery". Super Graphics has four types 1) Resident′s Super Graphics ; Minority groups came to maintain social equality and rights, in cooperation with each other. Such maintenance required general urbanites to form communities which gave birth to the community art, Mural Painting. 2) Environmental Super Graphics ; Beauty has come to be stressed in order to improve the quality of urban lives in the course of inescapable urban development. Instead of renewal of all established construction conservation oriented renewal was encouraged. 3) Super Graphics as Population Arts ; In the 1960′s artists repulsed the establishments in an efforts to open new phase independent from the expressional in the arts. They recognized the relationship between painting, society and the public in different angle and tried to describe all living space on canvas. 4) Super Graphics as Advertisement ; Super Graphics functions as efficient media to deliver images to the urbanites. Super Graphics as media plays the role for political propaganda and commercial advertisements according to their purposes. In Korea, especially, it is required to introduce the environmental Super Graphics. But it is desirable to introduce Super Graphics with Korean culture and sense of beauty. Designers themselves are also required to have responsibility to improve the quality of urban culture.

• 한국정보통신학회논문지
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• 제15권5호
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• pp.1018-1024
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• 2011

최대 토크를 발휘하도록 정현파형 영구자석형 동기전동기를 구동하기 위해서는 회전자 절대위치에 동기화된 120도 위상차를 갖는 3상 정현파 전류 입력이 고정자 코일에 요구된다. 그러므로 회전자 절대위치 검출이 필연적이다. 그리고 고정자 자계와 회전자 자계 사이의 90도 위상 관계가 정류 동작에 의해 유지되어야 한다. 정류를 위한 절대 위치 검출은 일반적으로 모터 축에 부착된 엔코더 출력 신호의 분석에 의해 이루어진다. 본 연구는 현대의 엔코더 시스템을 부착한 모터의 절대위치를 검출 할 수 있는 신호처리 논리회로 설계를 목적으로 하며, 고정자 코일에 정현파 전류 입력을 만들어주기 위한 삼상 기준파형을 발생시킨다.

• 한국의류학회지
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• 제31권4호
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• pp.633-645
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• 2007

The purpose of this study is to develop brassiere patterns which are both fitting and functional for women aged 19 to 24(the 1924 generation). We suggested a 'size chart for body measurements' for constructing basic brassiere patterns with six sizes of '70, 75', 'AA, A, B cups', which are used most frequently by the 1924 generation consumers. The scope of research was in reference to the statistical analysis results of the Size Korea(2004) body measurements and the results of the data from the preceding research. The 'drafting method for constructing basic brassiere patterns for the 1924 generation consumers' was completed by selecting a total of 18 subjects, 3 for each six sizes in the scope of research, and three wearing tests were carried out with the subjects. We compiled one brassiere pattern in six sizes obtained with the drafting method of constructing a basic brassiere pattern on another by block pattern in order to observe the phase of change in dimensions and shapes of paper pattern. The result was converted into the variations of a x-axis and a y-axis, and we suggested 'Size Grading Rule' and 'Cup Grading Rule' for the basic brassiere patterns. As the results of the wearing evaluation of the basic brassieres and measuring the variation in body dimensions by wearing brassieres, the dimensions and shapes of the basic brassieres suggested in this research proved to be fitting and to have a wearing effect that brings together and supports the breasts.

• Environmental Engineering Research
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• 제17권4호
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• pp.179-184
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• 2012

The light absorbance of photocatalysts and reaction kinetics of environmental pollutants at the liquid-solid and gas-solid interfaces differ from each other. Nevertheless, many previous photocatalytic studies have applied the science to aqueopus applications without due consideration of the environment. As such, this work reports the surface and morphological characteristics and photocatalytic activities of carbon-embedded (C-$TiO_2$) photocatalysts for control of gas-phase methyl tertiary-butyl ether (MTBE) under a range of different operational conditions. The C-$TiO_2$ photocatalysts were prepared by oxidizing titanium carbide powders at $350^{\circ}C$. The characteristics of the C-$TiO_2$ photocatalysts, along with pure TiC and the reference pure $TiO_2$, were then determined by X-ray diffraction, scanning emission microscope, diffuse reflectance ultraviolet-visible-near infrared (UV-VIS-NIR), and Fourier transform infrared spectroscopy. The C-$TiO_2$ powders showed a clear shift in the absorbance spectrum towards the visible region, which indicated that the C-$TiO_2$ photocatalyst could be activated effectively by visible-light irradiation. The MTBE decomposition efficiency depended on operational parameters, including the air flow rate (AFR), input concentration (IC), and relative humidity (RH). As the AFRs decreased from 1.5 to 0.1 L/min, the average efficiencies for MTBE increased from 11% to 77%. The average decomposition efficiencies for the ICs of 0.1, 0.5, 1.0, and 2.0 ppm were 77%, 77%, 54%, and 38%, respectively. In addition, the decomposition efficiencies for RHs of 20%, 45%, 70%, and 95% were 92%, 76%, 50%, and 32%, respectively. These findings indicate that the prepared photocatalysts could be effectively applied to control airborne MTBE if their operational conditions were optimized.

• 한국항해항만학회지
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• 제39권6호
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• pp.479-484
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• 2015

네트워크 RTK는 네트워크 내 다중 기준국의 반송파 측정치 보정정보를 활용하는 정밀 측위 기법으로 성능 개선을 목적으로 꾸준히 연구가 진행되어 왔다. 최근까지는 주로 측지 측량 분야에서 사용하였기 때문에 정확도 개선을 위한 연구 위주로 진행되었으며, 무결성 확보를 위한 연구는 아직 미비하다. 본 논문에서는 네트워크 RTK에서의 무결성 확보를 위한 기초연구로 네트워크 RTK 환경에 적합한 감시 시스템을 설계하였다. 이를 위하여 네트워크 RTK에서의 무결성 결함 조건을 도출하고, 각 결함 조건 별로 활용할 수 있는 이상 검출 및 식별 기법을 소개하였으며, 이를 기반으로 네트워크 RTK를 서비스하는 중앙처리국에서 활용할 수 있는 감시 시스템을 설계하였다.

• 대한기계학회논문집
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• 제12권5호
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• pp.1197-1205
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• 1988

본 연구에서는 피스톤운동을 톱날파로 근사하였을 때 단열된 실린더를 갖는 스터링기관에 대한 해석적인 해를 구하고자 한다. 실제기관에서 피스톤운동은 기구 학적 구동기구에 따라 상이하지만 대략적으로 정현파가 되며, 이 경우에는 해석적인 해가 존재하지 않으므로 수학적으로 구간선형적인 톱날파로 근사하였다. 비록 이러 한 근사를 도입한 단열해석이라 하더라도 해석적인 해가 존재한다면 등온해석보다는 기관성능의 예측에 더욱 적합함은 당연하다.

• 한국응용과학기술학회지
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• 제34권4호
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• pp.1112-1120
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• 2017

석유제품은 다양한 형태의 탄화수소화합물로 구성되어진 화합물로, 다른 종류의 액체류와 마찬가지로 온도변화에 따른 밀도와 부피의 변화가 발생한다. 액상에서 석유제품의 밀도를 측정하는 방법은 분별 증류된 각 석유제품에 대해 주로 얻어진 실험 데이터를 기반으로 한다. 본 연구에서는 등유와 자동차용 경유의 온도변화에 따른 밀도와 부피변화를 실제 측정하여 온도변화에 따른 변화추이를 분석하고, 국제규격인 ASTM에서 제시하는 밀도부피 환산표를 이용한 환산값을 계산하고 두 값을 비교분석하였다. 또한, 국내 계량 관련법에서 규정하고 있는 온도변화에 대한 기준과 실측값과의 상호 비교를 통해 차이점을 분석하였다.