• Journal of Electrical Engineering and Technology
• /
• 제10권4호
• /
• pp.1786-1795
• /
• 2015

It is common practice to identify the insulation faults of GIS through monitor the contents of SF₆ decomposed components. Partial discharges (PD) could lead to the decomposition of SF₆ dielectric, so new reactions usually occur in the mixture of the newly decomposed components including traces of H₂O and O₂. The new reactions also cause the decomposed components to differ due to the different amounts of H₂O and O₂ even under the same strength of PD. Thus, the accuracy of assessing the insulation faults is definitely influenced when using the concentration and corresponding change of decomposed components. In the present research, a needle-plate electrode was employed to simulate the PD event of a metal protrusion insulation fault for two main characteristic components SO₂F₂ and SOF₂, and to carry out influence analysis of trace H₂O and O₂ on the characteristic components. The research shows that trace H₂O has the capability of catching an F atom, which inhibits low-sulfide SF_x from recombining into high-sulfide SF₆. Thus, the amount of SOF₂ strongly correlates to the amount of trace H₂O, whereas the amount of SO₂F₂ is weakly related to trace H₂O. Furthermore, the dilution effect of trace O₂ on SOF₂ obviously exceeds that of SO₂F₂.

• Korea-Australia Rheology Journal
• /
• 제13권4호
• /
• pp.189-196
• /
• 2001

The phase morphology is an important factor in the rheology of immiscible polymer blends. Through its size and shape, the interface between the two phases determines how the components and the interface itself will contribute to the global stresses. Rheological measurements have been used successfully in the past to probe the morphological changes in model blends, particularly for dilute systems. For more concentrated blends only a limited amount of systematic rheological data is available. Here, viscosities and first normal stress differences are presented for a system with nearly Newtonian components, the whole concentration range is covered. The constituent polymers are PDMS and PIB, their viscosity ratio can be changed by varying the temperature. The data reported here have been obtained at 287 K where the viscosities of the two components are identical. By means of relaxation experiments the measured stresses are decomposed into component and interfacial contributions. The concentration dependence is quite different for the two types of contribution. Except for the component contributions to the shear stresses there is no clear indication of the phase inversion. Plotting either the interfacial shear or normal stresses as a function of composition produces in some cases two maxima. The relaxation times of these stresses display a similar concentration dependence. Although the components have the same viscosity, the stress-component curves are not symmetrical with respect to the 50/50 blend. A slight elasticity of one of the components seems to be the cause of this effect. The data for the more concentrated blends at higher shear rates are associated with a fibrillar morphology.

• 한국물환경학회지
• /
• 제23권4호
• /
• pp.551-560
• /
• 2007

The present study analyzed noise reduction and long/short-term components for discharge, TOC concentration, and TOC load data in order to understand the data characteristics better. For the purpose, wavelet transform which can reduce noise from raw data and has flexible resolution in time and frequency domain was applied and the theory of nonlinear dynamics was also used to determine the last decomposition level for wavelet transform. Wavelet function of 'db10' and the 7th level for the last decomposition of wavelet transform were applied for the all data in the present study. Also the results revealed that the energy ratios of approximation components with 187-hour periodicity decomposed from 7th level of wavelet transform were 94.71% (discharge), 99.00% (TOC concentration), and 93.84% (TOC load), respectively. In addition, the energy ratios of detail components showed the range between 1.00% and 6.17%, which were extremely small comparing to the energy ratios of approximation components, therefore, the first and second detail components might be considered as noise components included in the raw data.

• 사회복지연구
• /
• 제43권2호
• /
• pp.319-344
• /
• 2012

본 연구는 2010년 국민건강영양조사 원자료를 이용하여 의료이용 형평성지수인 집중지수와 Hiwv지수를 성별, 연령, 지역의 하위집단에 따라 집단 간 차이(Between)에 의한 부분과 집단 내부의 불평등(Within)에 의한 부분, 그리고 잔여 부분(R)으로 분해하였다. 본 연구의 분석결과는 다음과 같다. 첫째, 외래이용 횟수에서 남녀의 집단 간 차이가 Hiwv지수에 미치는 영향은 0으로 나타났다. 반면 외래비용에서는 Hiwv지수 .1035 중 여성들의 집단 내부불평등이 .0441을 설명하고 있어 빈곤여성들의 의료서비스 저이용이 의료이용 형평성에서 중요한 문제가 됨을 알 수 있었다. 둘째, 외래이용 횟수 형평성에 연령집단의 차이는 크게 영향을 미쳤는데, 미세한 양이지만 Hiwv지수 -.0107에서 대부분인 -.0085을 설명하고 있다. 셋째, 외래비용의 Hiwv지수에는 집단 내부의 불평등 특히, 노년층의 내부 불평등이 .0253을 설명하여 설명력이 크게 나타났다. 넷째, 외래비용의 Hiwv지수에 지역의 내부 격차(Within)가 가장 크게 영향을 미쳐서 Hiwv지수 .1035 중 .0569를 설명하였으며, 이 중 대부분인 .0535를 도시지역의 불평등이 설명하였다. 분석결과를 종합하면 분석된 집단범주 중 외래이용 횟수의 형평성에 가장 크게 영향을 미치는 집단은 연령집단이었으며, 외래비용에서는 집단 간 격차보다 집단 내부의 불평등이 더 크게 영향을 미치는 것으로 나타났다. 빈곤여성일수록, 빈곤노인일수록, 도시빈민일수록 기대비용에 못 미치는 외래진료비를 지출하고 있음을 나타냈는데, 이들에 대한 의료비지원 정책이 요구된다고 하겠다.

• 한국세라믹학회지
• /
• 제33권12호
• /
• pp.1331-1338
• /
• 1996

In order to investigate the reaction in the system of fly ash-sulfuric acid-calcium hydroxide the hydrates were produced by the addition of Ca(OH)2 to fly ash activated with sulfuric acid at various temperatures. And then they were characterized by XRD. SEM and TG-DTA. It was found that in the reaction of fly ash with sulfuric acid fly ash was not decomposed but Al2O3 and SiO2 component in it were activated. The addition of calcium hydroxide into this system resulted in the formation of ettringite and calcium silicate hydrate (C-S-H) As the concentration of sulfuric acid and reaction temperature increased the amount of calcium hydroxide decreased fast. At this time gypsum produced by the reaction calcium hydroxide with sulfuric acid was consumed to form ettringite. Accordingly the formation of ettringite increased with calcium hydroxide and reaction time. And it showed faster than the formation of C-S-H.

• 한국작물학회지
• /
• 제38권1호
• /
• pp.31-37
• /
• 1993

우리나라 주요 벼 재배품종 및 신육성계통(자포니카: 25품종, 통일형:8품종)에 대한 쌀 알칼리 붕괴성의 품종적 특이성을 분시검토하여 보고자 KOH 농도를 0.8-1.8까지 0.2% 간격으로 처리하여 농도별 쌀의 알칼리 붕괴반응을 조사하고 주성분분석법을 적용하여 품종적 유형을 분류하였다. 주성분분석에서 상위 2개 주성분치의 변이가 전변이량의 92%을 차지하였고 제1 및 제2 주요분치 좌표상의 품종분포에 따라 크게 4개 유형으로 군집화 시킬 수 있었다. 제 I 군에서는 전 KOH 농도에 걸쳐 거의 비슷하게 알칼리 붕괴성(ADV)가 낮은 도봉벼만 유일하게 분포하였고, 제 II군에는 1.4% KOH 농도에서 중간정도의 ADV 이면서 고-저 알칼리 농도 ADV간차가 중도인 백운찰벼, 신선찰벼 및 수원 34002 등 찰벼가 포함되어 있었다. 제 III군에는 1.4% KOH 농도에서 중-중고의 ADV 이면서 저-고 KOH 농도간 ADV 변화가 심했던 대부분의 통일형 품종과 자포니카 조생계가 분포되어 있었고 육도농림찰 001와 한강 찰벼등은 이 유형에 포함되어 있었다. 제 IV군에는 1.4% KOH 농도에서 ADV가 중고이상으로 높으면서 고-저 알칼리 농도 ADV간차가 중-중고인 중생 및 중만생 자포니카 품종들이 주로 분포 하였으며 조생인 금조벼가 이 유형에 속하였다. 여기서 제 1 주성분은 전 알칼리 농도에서 평균적으로 표현되는 붕괴성 정도였고 제 2 주성분은 저-고 KOH 농도의 ADV간 차 또는 KOH 농도에 따른 ADV 변화의 회귀계수와 밀접하게 관련된 요소였다. 1.2%-1.4% KOH 농도에서의 ADV는 저-고 KOH 농도간 ADV차와 2차 곡선 회귀계수를 나타내었다.

• Journal of Ginseng Research
• /
• 제15권2호
• /
• pp.112-116
• /
• 1991

The metabolic fate of ginsenosides including gastrointestinat absorption, organ distribution, excretion and metabolism in liver was investigated by tracer studies using the radio-labeled ginsenosides. 3H-ginsenosides were shown to be absorbed from the mouse digestive tract and then to be excreted rapidly into urine and/or bile. Bile juice was concluded to play a significant role in absorption of ginsenosides. The total concentration of radioactivity persisted in tissues 24 hrs after oral administration was less than 1.3% of the administered dose and Rbl showed the highest value. The concentrations of radioactivity were relatively high in the liver and kidney. After administration of Rbl radioactivity was detected in the brain. After oral administration of 8H-ginsenosides, major component excreted into urine was found to be the intact ginsenosides and decomposed and/or metabolized products were found in GIT in the case of Rbl. 3H-ginsenoside Rbl was shown to be metabolized in the liver and the metabolite was suggested to be an acylated compound of Rbl by a certain organic acid.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2001년도 제23회 KOSCO SYMPOSIUM 논문집
• /
• pp.169-178
• /
• 2001

Among the recent research ideas to reduce hydrocarbon emissions emitted from SI engines till light-off of catalyst since cold start are those exploiting non-thermal plasma technique and photo-catalyst that draws recent attention by virtue of its successful application to practical use to clean up the atmosphere using the feature of its relative independence on temperature. Based on the previous research results obtained with model exhaust gases using an experimental emissions reduction system that utilizes the non-thermal plasma and photo-catalyst technique, further investigation was conducted on a production N/A 1.5 liter DOHC engine during cold start to warm-up. For the effects of non-thermal plasma-photocatalyst combined reactor, 10% concentration reduction was achieved with the fuel component paraffins, and the large increase in non-fuel paraffinic components and acetylene concentrations were similar to those of base condition. However the absolute value was locally a bit higher than those of base condition since the products was made from the dissociation and decomposition of highly branched paraffins by plasma-photocatalyst reactor. Olefinic components were highly decomposed by about 75%, due to these excellent decompositions of olefins which have relatively high MIR values, and the SR value was 1.87 that is 30% reduction from that of base condition, then, the photochemical reactivity was lowered.

• 한국물환경학회지
• /
• 제33권4호
• /
• pp.487-493
• /
• 2017

This study was conducted to propose measures of water quality management as the water criteria for waterscape facilities which have been highlighted as alternatives to wading pools in summer season was legislated. The number of public waterscape facilities has reached 290 sites in Gyeounggi province and 971 sites in South Korea in 2017. The water tank capacity of 80.3 % public waterscape facilities was less than $100m^3$. Facilities with disinfection system were only 6.5 % and facilities with filtration function were also very low at 6.9 %. Most of the waterscape facilities, about 93%, are expected to be vulnerable to complying with revised water quality criteria because they have to be disinfected by handling. Chlorine disinfectants, which are more persistent than ozone or ultraviolet sterilization methods, are more preferred. However, care should be taken when adding disinfectans because hypochlorous acid, which is an effective component of chlorine disinfectant, remains after the disinfection, but it is easily decomposed with time. For this study, ${\bigcirc}{\bigcirc}$ park floor fountain with a capacity of $63m^3$ was selected and the amount of free residual chlorine concentration was measured by injecting a certain amount of chlorine bleach. As a result, it took 5 hours to decrease from the water quality standard of 4 mg/L to 0.04 mg/L. If the waterscape facility is operated for 7 to 8 hours, the chlorine bleach should be re-injected after 5 hours. In addition, the problem of pH increase due to the input of chlorine disinfectant is expected, and the neutralization method using vinegar was proposed.

• Ocean and Polar Research
• /
• 제29권2호
• /
• pp.87-99
• /
• 2007

This study was conducted to understand the source and behavior of organic matter using the fluorescent technique (excitation-emission matrix) as a part of environmental monitoring program in the Korea manganese nodule mining site in the Northeastern Pacific Ocean. Water samples were collected at $0^{\circ},\;6^{\circ}N$, and $10.5^{\circ}N$ along $131.5^{\circ}W$ in August 2005. The concentration of total organic carbon (TOC) ranged from 58.01 to $171.93\;{\mu}M-C$. The vertical distribution of TOC was characterized as higher in the surface layer and decreased with depth. At $6^{\circ}N$, depth-integrated (from surface to 200 m depth) TOC was $337.1\;gC/m^2$, which was 1.4 times higher value than other stations. The exponential decay curve fit of vertical profile of TOC indicated that 59% of organic carbon produced by primary production in the surface layer could be decomposed by bacteria in the water column. Dissolved organic matter is generally classified into two distinctive groups based on their fluorescence characteristics using three-dimensional excitation/emission (Ex/Em) fluorescence mapping technique. One is known as biomacromolecule (BM; protein-like substance; showing max. at Ex 280/Em 330), mainly originated from biological metabolism. The other is geomacromolecule (GM; humic-like substance; showing max. at Ex 330/Em 430), mainly originated from microbial degradation processes. The concentration of BM and GM was from 0.42 to 7.29 TU (tryptophan unit) and from 0.06 to 1.81 QSU (quinine sulfate unit), respectively. The vertical distribution of BM was similar to that of TOC as high in the surface and decreased with depth. However, the vertical distribution of GM showed the reverse pattern of that of BM. From these results, it appeared that BM occupied a major part of TOC and was rapidly consumed by bacteria in the surface layer. GM was mainly transformed from BM by microbial processes and was a dominant component of TOC in the deep-sea layer.