• 제목/요약/키워드: cut off level

검색결과 313건 처리시간 0.025초

심층혼합기둥체 차수벽을 이용한 중금속 오염물질의 이동 제어 (Containing Heavy Metal Contaminants Using Soil-Cement Column Barrier)

  • 정문경;천찬란;이주형;김강석
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2003년도 봄 학술발표회 논문집
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    • pp.821-826
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    • 2003
  • Laboratory experiments were peformed to understand physical properties of soil-cement column under the influence of acidic flow including metal contaminants and its retaining capacity against metal migration. The contaminant used in this study was nitric acid with Cu and Cd. The Permeability of soil-cement column decreased when pH of the column began to drop below 12. Decreases in pH led to significant reduction of compressive strength of clayey soil-cement specimen, while relatively marginal reduction for sandy soil-cement specimen. The metal contaminants did not leachate from soil-cement column until pH of soil-cement dropped below 7∼8 for Cu and 9∼10 for Cd. Metal contaminants were precipitated and trapped inside the soil-cement column at pHs higher than those mentioned as verified with metal analysis and visual inspection. This indicated that soil-cement column not only performs well as a cut-off wall, but also helps alleviating the level of contamination of the surrounding environment.

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부부의 자아분화 수준에 따른 부부갈등과 결혼만족도에 관한 연구 (A Study on Self-differentiation, Marital Conflict and Marital Satisfaction among Couples')

  • 한영숙
    • 한국생활과학회지
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    • 제16권2호
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    • pp.259-272
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    • 2007
  • The purpose of this study was to investigate the effect of couples' self-differentiation by marital satisfaction according to couple's gender. The participants of the present study were 728 couples who lived in Chonbuk province. The data were collected by self-administered questionnaire method. Self-differentiation scale was consisted of such factors as emotional reactivity, I-position, emotional cut-off and fusion with others. The results of this research were as follows: First, there was significant difference in the level of total self-differentiation between husbands and wives. Second, there was significant difference in the levels of marital conflict and of marital satisfaction to levels of self differentiation. Third, self differentiation in both husbands and wives had an direct effect on marital satisfaction and stability through marital conflict. Fourth, marital conflict in both husbands and wives had a direct effect on marital satisfaction.

고 흡입저항을 가진 원심 송풍기 (Centrifugal Blower with High Inlet Resistance)

  • 김재원
    • 한국유체기계학회 논문집
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    • 제6권2호
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    • pp.15-22
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    • 2003
  • Comprehensive study on a centrifugal blower for air-purifier involving a few physical filters for percolation process has been accomplished for an optimal design of the air handling system. The filtering media causes a flow resistance for induced flows by a rotating impeller. The present methodology is to adopt PIV system for velocity measurements and wind tunnel connected with an anechoic chamber for total performance test of the blower. Trial prototypes for the blades of a rotor and casing are presented for satisfaction of both flow rate and noise level set by design objectives. Tapered blades with a special casing for a fan show good performance data. The results of velocity fields also explain the reason of improvements of the blower performance.

주거환기용 시로코홴의 공력 및 소음 특성 연구 (A Study on Aerodynamic and Noise Characteristics of a Sirocco Fan for Residential Ventilation)

  • 김진혁;송우석;이승배;김광용
    • 한국유체기계학회 논문집
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    • 제13권2호
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    • pp.18-23
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    • 2010
  • This paper presents a procedure for the aerodynamic and aeroacoustic characteristics of a sirocco fan. For the aerodynamic and aeroacoustic analyses of the sirocco fan, three-dimensional steady and unsteady Reynolds-averaged Navier-Stokes equations are solved with a shear stress transport turbulence model for turbulence closure. The flow analyses were performed on a hexahedral grid using a finite-volume solver. The validation of the numerical results is performed by comparing with experimental data for the pressure, efficiency and power. The internal flow analyses of the sirocco fan are performed to understand the unstable flow phenomenon on the casing for the wall pressure and internal flow characteristics at each position. It was found that fluctuation of pressure and locally concentrated noise source are observed near the cut-off and expansion regions of the casing.

Low-frequency Mosaicism of Trisomy 14, Missed by Array CGH

  • Lee, Cha Gon;Yun, Jun-No;Park, Sang-Jin;Sohn, Young Bae
    • Journal of Genetic Medicine
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    • 제10권1호
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    • pp.52-56
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    • 2013
  • Mosaic trisomy 14 syndrome is a well-known but unusual chromosomal abnormality with a distinct and recognizable phenotype. Array comparative genomic hybridization (CGH) analysis has recently become a widely used method for detecting DNA copy number changes, in place of traditional karyotype analysis. However, the array CGH shows a limitation for detecting the low-level mosaicism. Here, we report the detailed clinical and cytogenetic findings of patient with low-frequency mosaic trisomy 14, initially considered normal based on usual cut-off levels of array CGH, but confirmed by G-banding karyotyping. Our patient had global developmental delay, short stature, congenital heart disease, craniofacial dysmorphic features, and dark skin patches over her whole body. Estimated mosaicism proportion was 23.3% by G-banding karyotyping and 18.0% by array CGH.

배기용 Fan Scroll에 대한 연구 (A Study on the Fan and Scroll for Ventilation)

  • 송성배;박성일;이준세
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 춘계학술대회논문집
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    • pp.402-406
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    • 2000
  • In the Over-The-Range, the outlet size is limited by the industrial standards. Therefor to enlarge the volume of cavity, the installation height of ventilation fan is become small, the system resistance is higher than before. For that reason, the important design variables such as the diameter of a fan, the scroll expansion angle, etc. which play the significant role on flow rate and noise, are confined. In this study, we made an experiment of the diameter of fans relation to scroll expansion angle and investigated flow rate of the length of fans in enlarged cavity volume of OTR, and then we designed the new scroll to improve the flow rate and noise level. As a result, flow rate increased to 110% compared to current scroll and the blade passing frequency of a fan is disappeared by inclined cut-off shapes.

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정신병리아동 부모의 자아분화, 가족기능 관한 연구 (Self-Differentiation and Family Function in Parents of Children with Psychopathology)

  • 황규선;최연실
    • 아동학회지
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    • 제23권6호
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    • pp.65-79
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    • 2002
  • The present study surveyed both the parents of 130 children with psychopathology and the parents of 240 normal children. children were between 2 and 12 years of age. No differences were found between parents in self-differentiation or in family function by type of disorder. Parents of children with psychopathology were lower than parents of normal children in self-differentiation; this was particularly evident in cognitive function-emotional function, and emotional cut-off. Patents of children with psychopathology were lower than parents of normal children in terms of family function. Multiple regression analyses indicated that parent's self-differentiation, children's psychopathology, and parent's education level had a significant influence on family function. The regression model explained 52% of the variance.

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GC/MS에 의한 한국인의 모발중 Methamphetamine검출 (Determination of methamphetamine in the hair of Korean abuser by CG/MS)

  • 유영찬;정희선;최화경
    • 약학회지
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    • 제37권4호
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    • pp.356-361
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    • 1993
  • A sensitive method for the determination of methamphetamine(MA) and amphetamine(AM) in hair was developed by gas chromatography/mass spectrometry using stable isotope-labeled internal standards, amphetamine-d$_{5}$ and methamphetamine-d$_{5}$. Hair sample was washed with MeOH, incubated with MeOH(I% HCI) overnight at $37^{\circ}C$ while stirring and extracted using solid phase extraction column on a vacuum manifold. The extract obtained was pentafluoropropionated, and applied to GC/MS. The calibration curves of MA and AM were linear from 2.5 to 250 ng (r>0.99 for both). The limit of detection was 0.1 ng/mg in hair and cut-off level was set at 0.25 ng/mg for both. Hair samples of 27 MA abusers showed positive results in the range 0.7 to 106.8 ng/mg. AM, its metabolite, was detected in 20 out of 27 samples. The ratio of MA versus AM was 4.6~38.3 in specimens. Hair analysis for methamphetamine by GC/MS is an effective method for identifying long-term drug abusers.

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Surface Relaxation of Aluminum

  • Cha, You-Yong;Han, Wone-Keun
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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    • pp.142-142
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    • 2000
  • We performed a total energy calculation of clean alumunum surfaces of three low indices based on a density functional theory with a local density approximation, using the Ceperly-Alder exhange correlation parametrized by Perdew and Zunger. Pseudopotentials were generated for Al of which the plane wave cut-off was 15Ry. We used Gaussian broadening of a Fermi level to accelerate the convergence of our calculation with the Gaussian energy smearing parameter of 0.005Ry. First, we determine the lattice constant of the aluminum of an face-centered-cubic structure to be 3.96 which is comparable to the experimental data of 4.05 . The cohesive energy of 4.20eV/atom and the bulk modulus of 0.775$\times$1012dyne/cm2 are also comparable to the experimental values of 3.39eV/atom and 0.772$\times$1012dyne/cm2, respectively. Then we investigated the surface relaxation of (100), (110) and (111) surfaces using a 9-layer slab separated by 6-layer thick vacuum. The results are consistent with the existing experimental results.

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THE VALIDITY TESTS OF ARTICULATION LISTS USING THE EFFECTS OF MONAURAL AND BINAURAL FACTORS

  • Kim, Jeong-Hwan;Kang, Seong-Hoon;Jang, Dae-Young
    • 한국음향학회:학술대회논문집
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    • 한국음향학회 1994년도 FIFTH WESTERN PACIFIC REGIONAL ACOUSTICS CONFERENCE SEOUL KOREA
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    • pp.1058-1063
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    • 1994
  • In this study we developed monosyllable lists for articulation test for Korean. We sampled 103,581 colloquial monosyllables, applied them to five selection rules that based on Korean linguistic characteristics, and finally constructed five different lists with fifty monosyllables. The validity test using the monaural impairment factors such as S/N ratio and cut-off frequency showed that articulation scores were chanted systematically according to the level of impairment factors. In addition, we investigated the effect of azimuth of a single competing sound upon articulation scores. The syllables were always reproduced by the loudspeaker in front of the subject, while Hoth noise were reproduced by the loudspeaker with varying azimuth around subject. The result indicated that the articulation depended on the azimuth of competing sound sources. Finally, no significant differences among lists were found in all experimental conditions.

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