• Title/Summary/Keyword: S/L ratio

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Desorption Kinetics and Removal Characteristics of Pb-Contaminated Soil by the Soil Washing Method: Mixing Ratios and Particle Sizes

  • Lee, Yun-Hee;Oa, Seong-Wook
    • Environmental Engineering Research
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    • v.17 no.3
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    • pp.145-150
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    • 2012
  • Pb-contaminated soil at a clay shooting range was analyzed by the sequential extraction method to identify metal binding properties in terms of detrital and non-detrital forms of the soil. Most of the metals in the soils existed as non-detrital forms, exchangeable and carbonate-bound forms, which could be easily released from the soil by a washing method. Therefore, the characteristics of Pb desorption for remediation of the Pb-contaminated soil were evaluated using hydrochloric acid (HCl) by a washing method. Batch experiments were performed to identify the factors influencing extraction efficiency. The effects of the solid to liquid (S/L) ratio (1:2, 1:3, and 1:4), soil particle size, and extraction time on the removal capacity of Pb by HCl were evaluated. Soil samples were collected from two different areas: a slope area (SA) and a land area (LA) at the field. As results, the optimal conditions at 2.8 to 0.075 mm of particle size were 1:3 of the S/L ratio and 10 min of extraction time for SA, and 1:4 of the S/L ratio and 5 min of extraction time for LA. The characteristics of Pb desorption were adequately described by two-reaction kinetic models.

Importance of Zinc Oxide Nanoparticle Concentration on the Electrical Properties of Lead Sulfide Quantum Dots-Based Shortwave Infrared Photodetectors (황화납 양자점 기반 단파장 적외선 수광소자의 전기적 특성 향상을 위한 산화아연 나노입자 농도의 중요성)

  • Seo, Kyeong-Ho;Bae, Jin-Hyuk
    • Journal of Sensor Science and Technology
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    • v.31 no.2
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    • pp.125-130
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    • 2022
  • We describe the importance of zinc oxide nanoparticle (ZnO NP) concentration in the enhancement of electrical properties in a lead sulfide quantum dot (PbS QD)-based shortwave infrared (SWIR) photodetector. ZnO NPs were synthesized using the sol-gel method. The concentration of the ZnO NPs was controlled as 20, 30 and 40 mg/mL in this study. Note that the ZnO NPs layer is commonly used as an electron transport layer in PbS QDs SWIR photodetectors. The photo-to-dark ratio, which is an important parameter of a photodetector, was intensively examined to evaluate the electrical performance. The 20 mg/mL condition of ZnO NPs exhibited the highest photo-to-dark ratio value of 5 at -1 V, compared with 1.8 and 0.4 for 30 mg/mL and 40 mg/mL, respectively. This resulted because the electron mobility decreased when the concentration of ZnO NPs was higher than the optimized value. Based on our results, the concentration of ZnO NPs was observed to play an important role in the electrical performance of the PbS QDs SWIR photodetector.

Mixed Convection Heat Transfer from Two Vertical Parallel Plates with Different Conditions (조건이 다른 수직 평형 평판에서 혼합대류 열전달)

  • Kim, S.Y.;Chung, H.S.;Kwon, S.S.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.4 no.4
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    • pp.243-252
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    • 1992
  • A mixed convection heat transfer from two vertical parallel plates has been studied numerically by the finite difference method. Effects of the Grashof number, the relative length, $L_2/L_1$. the dimensionless temperature ratio, ${\Phi}_2/{\Phi}_1$ and the dimensionless plate spacing, $b/L_1$ are examined for the heat transfer. Independent of the Grashof numbers and $L_2/L_1$, the dimensionless vertical velocity distributions skewed on the left plate as ${\Phi}_2/{\Phi}_1$ decreased. The dimensionless vertical velocity distribution for $Gr/Re^2=1$ and ${\Phi}_2/{\Phi}_1=1.0$ is skewed to the right plate $L_2/L_1=0.5$, symmetric at $L_2/L_1=1.0$ and skewed to the left plate at $L_2/L_1=1.5$. But for $Gr/Re_2=10.0$ and ${\Phi}_2/{\Phi}_1=1.0$ reversed velocity patterns are obtained. Regardless of the Grashof numbers and $L_2/L_1$, the mean Nusselt nembers on the inside surface of the left plate decreases and those of the right inside surface increases as ${\Phi}_2/{\Phi}_1$ increases. Temperature, velocity and mean Nusselt number distributions are apparently not affected by $L_2/L_1$.

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A Study on w6/w3 and P/M/S Ratios of Fatty Acids Ingested by University Students (일부 대학생의 지방산 섭취량과 섭취지방산의 w3, w6계 지방산 및 P/M/S 비율에 관한 연구)

  • 오경원;박계숙;김택제;이양자
    • Journal of Nutrition and Health
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    • v.24 no.5
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    • pp.399-407
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    • 1991
  • The purpose of this study was to estimate the intake of individual fatty acid and eventually to contribute to the establishment of dietary guidelines and recommendations of fatty acids for the Koreans. The subjects consisted of female college students aged 20 to 29 years old. Their dietary intake was assessed twice. in summer and in winter, by means of a 24-hour dietary recall method. Food models and other measuring tools were also used. Concentrations of serm total triglyceride, total cholesterol and HDL-& LDL-cholesterol were measured. The subjects consumed 12.3g of polyunsaturated fatty acids, 14.3g of monounsaturated fatty acids and 14.99g of saturated fatty acids per day The ratios of polyunsaturated/saturated fatty acids( P/S) and polyunsaturatedimonounsaturatedi saturated fatty acids (P/M/S) taken by the subjects were 0.8/1.0 and 0.8/l.0/l.0, respectively. The ratio of w61w3 fatty acids was found to be 8.3/l.0. All of these values seem to fall in the desirable range. The percentages of total calorie from carbohydrate. fat and protein were 59.4%, 23.4% and 17.2%, respectively. The concentrations of serum total triglyceride, total cholesterol. HDL-cholesterol and LDL-cholesterol were 59.3ms/dl, 192.7mg/dl, and 59.0mg/dl, and 121.9mg/dl., respectively.

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Developmental Delay Effect of Harpacticoid Copepod, Tigriopus japonicus s.l. Exposure to 4-tert-octylphenol (4-tert -octylphenol에 노출된 저서성 요각류 Tigriopus japonicus s.l.의 발생지연 현상)

  • Bang, Hyun-Woo;Lee, Won-Choel;Kwak, Inn-Sil
    • Environmental Analysis Health and Toxicology
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    • v.23 no.2
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    • pp.93-100
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    • 2008
  • The ecotoxicological effects of 4-tert-octylphenol were observed on Harpacticoid copepoda Tigriopus japonicus s.l. gathered and cultured from tidal pool of Korean coast. There were no significant differences in survival rate (except 10 $\mu$g/L; 70.00%) and sex ratio (except 30 $\mu$g/L) on T. japonicus s.l. exposed to 4-tert-octylphenol. However, 4-tert-octylphenol induced developmental delay (copepodite emergence day and adult male mergence day) and retardation of first brooding day of adult female. Moreover the body size and biomass decreased at 4-tert-octylphenol exposure. As a result, detailed life-cycle research of T. japonicus s.l. may yield potential bioindicators for environmental monitoring and assessment.

Change Soil Water and Evaluation with Respect to Shallow-Extensive Green Roof System (저토심 옥상녹화시스템에 따른 토양수분의 변화)

  • Park, Jun-Suk;Park, Je-Hea;Ju, Jin-Hee;Yoon, Yong-Han
    • Journal of Environmental Science International
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    • v.19 no.7
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    • pp.843-848
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    • 2010
  • This study focused on the characteristics of change soil water with respect to soil thickness and soil mixture ratio, in order to effectively carry out an afforestation system for a roof with a low level of management and a light weight. Soil hardness tended to increase as sand particle was increase regardless soil thickness and soil porosity had more higher artificial soil than natural soil mixture. In case of soil pH, natural soil mixture had between 6.7 and 7.4, and artificial soil mixture had 6.0~6.8. Organic matter, electrical conductance and exchangeable content were highest in $L_{10}$, which it had the highest leafmold ratio. Soil moisture tension(kPa) in 15cm soil thickness was observed natural soil mixture had a considerable change but artificial soil mixture had a gradual change when non-rainfall kept on. In the experimental $L_{10}$, $S_{10}$, $S_7L_3$ and $S_5L_5$ object, the amount of moisture tended to rapidly decrease. However, in the experimental $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$ and $P_4P_4L_2$ objects, which contained pearlite and peat moss, the amount of moisture tended to gradually decrease. As a result, the use of a artificial soil mixture soil seems to be required for the afforestation of a roof for a low level of management.

Effects of Soil Acidification on Growth of Impatiens balsamina L. and Tagetes patula L. Plants (토양산성화가 봉선화(Impatiens balsamina L.) 및 만수국(Tagetes patula L.)의 생장에 미치는 영향)

  • 김학윤
    • Journal of Life Science
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    • v.11 no.2
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    • pp.153-158
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    • 2001
  • To investigate the effects of soil acidification on growth of Impatiens balsamina L. plants were transplanted to acidified soils with H$_2$SO$_4$ solution. The concentrations of soluble Ca, Mg, K, Al and Mn in the acidified soils increased with increment of H$^{+}$ addition to the soil. In both species, the plant height and root length were inhibited by soil acidification, showing much severer inhibition in Impatiens balsamina L. than in Tagetes patula L., As the soil pH decreases, the growth of underground parts decreased greatly than that of above ground parts in both species. Total dry weight decreased with increased Al concentration as well as lowered soil pH in both plants. There was a strong positive correlation between relative total dry weight and molar (Ca+Mg+K) / Al ratio of the soil. The results suggest that molar(Ca+Mg+K)/ Al ratio of the soil may be useful indicator for assessing the critical load of acid deposition in herb species.s.

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Identification of Quantitative Trait Loci Associated with Leaf Length. Width and Length/width Ratio in Two Recombinant Inbred Lines of Soybean (Glycine max L.) (두 집단의 재조합 근친교잡 계통 (RIL) 콩에서 엽장과 엽폭 및 장폭비와 관련된 양적헝질 유전자좌 분석)

  • Kim, Hyeun-Kyeung;Kang, Sung-Taeg
    • Journal of Life Science
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    • v.14 no.5
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    • pp.821-828
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    • 2004
  • The increasing apparent photosynthetic rate per leaf area may improve seed yield in soybean. Leaf area, length and width are related to the photosynthetic capability of the plant. In this study, two populations derived from the cross of Keunolkong, Shinpaldalkong and Iksanl0 were evaluated with simple sequence repeat (SSR) markers to identify length, width and length/width ratio of leaf. Leaf length/width ratio were significantly negative correlation with leaf width in K/S and K/I populations. In the K/S population, two minor QTLs for leaf length (LL) were found on LG Dlb+W and 1. Two QTLs on LG J and L were related to LL in K/I population. Two and three minor QTLs were identified in leaf width with total phenotypic variation of 13% and 18.04 in K/S and K/I populations, respectively. The leaf length/width ratio, two QTLs on LG I and L, and three QTLs on LG Cl, E and L were related to K/S and K/I populations, respectively. Thus it is assumed that the leaf traits are very much dependent on the genotype used and different breeding approach should be considered for the selection of favorite leaf traits in soybean breeding programs.

Assessment of creep improvement of organic soil improved by stone columns

  • Kumail R. Al-Khafaji;Mohammed Y. Fattah;Makki K. Al-Recaby
    • Geomechanics and Engineering
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    • v.38 no.2
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    • pp.191-203
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    • 2024
  • One of the issues with clayey soils, particularly those with significant quantities of organic matter, is the creep settling problem. Clay soils can be strengthened using a variety of techniques, one of which is the use of stone columns. Prior research involved foundation loading when the soil beds were ready and confined in one-dimensional consolidation chambers. In this study, a particular methodology is used to get around the model's frictional resistance issue. Initially, specimens were prepared via static compaction, and they were then re-consolidated inside a sizable triaxial cell while under isotropic pressure. With this configuration, the confining pressure can be adjusted, the pore water pressure beneath the foundation can be measured, and the spacemen's lateral border may be freely moved. This paper's important conclusions include the observation that secondary settlement declines with area replacement ratio. Because of the composite ground's increasing stiffness, the length to diameter ratio (l/d) and the stone column to sample height ratio (Hc/Hs) both increase. The degree of improvement varies from 12.4 to 55% according to area replacement ratio and (l/d) ratio.

New S-PVA Technology for Advanced LCD Performance

  • Um, Yoon-Sung;Park, Seung-Beom;Kim, Hoon;You, Hye-Ran;Lyu, Jae-Jin;Kim, Kyeong-Hyeon;Kim, Sang-Soo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.403-406
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    • 2007
  • A New S-PVA which is named as charge-shared super PVA (CS S-PVA) LCD mode is proposed. CS SPVA controls the voltage ratio of low pixel by sharing system between low pixel and control cap, resulting in improved off-axis image quality and transmittance increase without any side effects. Moreover, the new S-PVA LCD mode is free of image-sticking. Operating schemes and display performance of CS S-PVA are presented.

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