• Title/Summary/Keyword: critical concentration

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A Study on Changes of Serum $fT_3\;and\;rT_3$ Concentration in Nonthyroidal Critical Illness (비갑상선 중증 질환에서 혈청 $fT_3$$rT_3$의 변화에 관한 연구)

  • Lee, Jong-Wha;Kim, Ju-Ock;Yu, Cheol-Jae;Moon, Youn-Sung;Shin, Young-Tae;Ro, Heung-Kyu
    • The Korean Journal of Nuclear Medicine
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    • v.19 no.1
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    • pp.103-111
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    • 1985
  • Recently changes in thyroid physiology during acute and chronic medical illness were demonstrated. The serum $fT_3,\;rT_3,\;T_4,\;T_3,\;fT_4$, and TSH concentration were measured by radioimmunoassay method in 49 patients with critical illness and 10 normal subjects to assess the change of thyroid function in critical illness. The results were as follows; 1) The mean serum $fT_3$ concentration was $6.68{\pm}1.05pmol/ml$ in normal subjects while in patients with critical illness the serum $fT_3$ concentration was significantly lowered to $1.55{\pm}1.15pmol/ml$(p<0.001). 2) The mean serum $rT_3$ concentration was $0.22{\pm}0.44ng/ml$ in normal subjects and $0.42{\pm}0.37ng/ml$ in patient with critical illness. There was increment in critically ill patients as compared to normal subjects but no statistically significant difference(p>0.05). 3) The mean serum $T_3$ concentration was $1.24{\pm}0.25ng/ml$ in normal subjects and $0.56{\pm}0.56ng/ml$ in patients with criticial illness and there was significant difference in each other(p<0.005). 4) The mean serum $T_4,\;fT_4$, and TSH concentrations were $7.80{\pm}1.02{\mu}g/dl,\;1.26{\pm}0.39ng/dl,\;1.87{\pm}0.45{\mu}U/ml$ in normal subjects respectively and $6.02{\pm}3.06{\mu}g/dl,\;1.46{\pm}0.80ng/dl,\;1.74{\pm}0.79{\mu}U/ml$ in patients with critical illness and there was no significant difference between critically ill patients and normal subjects. 5) The ratio of mean serum concentration of $fT_3$ and $rT_3(fT_3/rT_3)$, $30.42{\pm}5.58$ in normal subjects was significantly higher(p<0.005) than the coresponding patients with critical illness. 6) The mean serum $fT_3$ concentration in expired cases(n=12) during admission was significant difference between expired and survived cases(p<0.005). The mean serum $rT_3$ centration was $0.67{\pm}0.58ng/ml$ in expired cases and $0.34{\pm}0.22ng/ml$ in survived cases with significant difference(p<0.005). Half of the cases who showed less than $3{\mu}g/dl$ of serum $T_4$ level were expired.

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The Effect of Sb2O3 Additive on the Electrical Properties of ZnO Varistor (Sb2O3 첨가제가 ZnO 배리스터의 전기적 특성에 미치는 영향)

  • Kim, Yong-Hyuk
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.10
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    • pp.1697-1701
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    • 2016
  • The leakage conduction and critical voltage characteristic of ZnO ceramic were investigated as a function of $Sb_2O_3$ concentration. Leakage conduction in the ohmic region increased with increasing $Sb_2O_3$ concentration and was attributed to the potential barrier height. The nonlinear coefficient increased with an increasing amount of $Sb_2O_3$. It was found that increases in the apparent critical voltages were associated with the lowered donor concentration in the grain boundary of between two ZnO grains. And the decrease of donor concentration on doping with $Sb_2O_3$ additive was attributed to the lowered capacitance in the grain boundary layer.

On the Critical Behavior of Phase Changes of a Forward-Scattered Light in a Nonpolar Binary Liquid Mixture

  • Kim, Kyoung-Ran;Kang, Young-Soo;Lee, Dong-J.
    • Bulletin of the Korean Chemical Society
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    • v.23 no.12
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    • pp.1749-1753
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    • 2002
  • The effect of concentration fluctuations on the changes of azimuth and ellipticity are analytically obtained in a binary chiral liquid mixture, when the incident light is completely linearly polarized above (or below) the horizontal at 45°. The important results are as follows;(1) When the binary liquid is in the critical region far from the cr5itical point, the ellipticity change is proportional to isothermal compressibility factor and the fifth order of frequency and shows the logarithmic divergence. (2) In the case that the system is in the critical region far from the critical point, the azimuth change is solely due to the molecular contribution. As the system approaches to the critical point, the effect of fluctuations becomes important. If it is in the extreme close to the critical point, the term due to the concentration fluctuations is comparable to or larger than the molecular contribution.

Study on the Characteristics of Surface Ozone Distributions and the Ozone Critical Levels to Vegetation in the South Korea (남한 지역의 지면 오존 농도 특성과 식생에 대한 임계값 적용 연구)

  • Koo, Hae-Jung;Park, Soon-Ung
    • Journal of Korean Society for Atmospheric Environment
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    • v.24 no.3
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    • pp.310-320
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    • 2008
  • Concentration of tropospheric ozone ($O_3$) was investigated for the South Korea. And then the critical ozone levels, expressed as AOT40 (Accumulated exposure over a threshold of 40 ppb) to vegetation have been used in this region within the UNECE (United Nations Economic Commission for Europe) Convention on Long-Range Trans-boundary Air Pollution (CLRTAP). Hourly ozone concentration data from 1996 to 2001 at 26 air monitoring stations was used to estimate the exceedance of the critical levels. It was calculated for daylight hours for each station, and mapped using surface interpolation over the South Korea. The critical levels of ozone have shown the highly exceeded value in the Gyeonggi region, southern coastal region and central inland of the South Korea. It was some different from the typical ozone distribution which represented highly in the western inland and coastal regions. The area exceeding the critical level for crops was founded to be more than 40% of the whole South Korean territory. While that for trees was to be about 17% of the South Korea. The critical ozone critical level was based upon data from experiments on specific species, and thus may not be fully representative for all types of vegetation. Nevertheless, the critical level and its exceedance of the ozone concentration would be one of the useful tools for international agreements on abatement strategies to prevent ecosystem damage.

Effect of Jokyungiongoktang on the Fluctuation of Gonadotropin and Sex Hormone Concentration In Serum of Women (조경종옥탕(調經種玉湯)의 투여(投與)가 여성(女性)의 성선자극(性腺刺戟)호르몬 및 성(性)호르몬의 동태(動態)에 미치는 영향(影響))

  • Bae, Jong-Kook;Kim, Gil-Whon
    • The Journal of Dong Guk Oriental Medicine
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    • v.1
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    • pp.15-54
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    • 1992
  • The present study was accomplished to investigate the relation between menstrual cycle and ovulation by studying the fluctuation of FSH, LH, estrogen and progesterone concentration in serum samples of selected senior high school women with normal and delayed menstrual cycles after administration of Jokyungijongoktang which was a widely used herb medicine for controlling abnormal menstrual cycles. The obtained results were summarized as follows : 1. There was a significant increase of FSH concentration in women with delayed menstrual cycles after administration of Jokyungjongoktang during the preovulatory phase. 2. Jokyungiongoktang produced a significant elevation od LH concentration in women with normal and delayed menstrual cycles, respectively, during the critical interval of ovulation. 3. Estrogen concentration was significantly decreased in women with delayed menstrual cycles after administration of Jokyungjongoktang during the critical interval of ovulation. 4. Peogesterone concentration significantly increase in women with delayed menstrual cycles after administration of Jokyungjongoktang, respectively, during the postovulatory phase. According to the above results, it can be considered that Jokyungjongoktang restore menstruation and pregnancy-related hormones to normal serum levels of women with normal menstrual cycles by activating maturation of ovum and action of estrogen during the preovulatory phase, ovulation and progesterone synthesis during the critical interval of ovulation, and nidation and endometrium sufficient for the continued pregnacy during the postovulatory phase in women with delayed menstrual cycles.

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The Surface Tension and the C. M. C. of the Solution of Dodecylpyridinium Bromide (Dodecylpyridinium Bromide 溶液의 表面張力과 C. M. C.)

  • Han, Man-Un;Lee, Chong-Man;Kim, Tae-Woo
    • Journal of the Korean Chemical Society
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    • v.9 no.3
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    • pp.124-127
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    • 1965
  • The surface tension of the solution of dodecylpridinium bromide was measured by the ring method over the range $25^{\circ}\; to\; 45^{\circ}C.$ The critical micelle concentration was determined from the change of the surface tension of solution with concentration. The temperature dependence of the critical micelle concentration was also investigated. The result was compared with Adderson and Taylor's data determined by the conductivity method.

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Determination of Critical Nitrogen Concentration and Dilution Curve for Rice Growth

  • Lee, Byun-Woo;Cui, Ri-Xian;Kim, Min-Ho;Kim, Jun-Hwan;Nam, Hong-Shik
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.47 no.2
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    • pp.127-131
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    • 2002
  • Critical nitrogen concentration (Nc), which is defined as the minimum % N in shoots required to maintain the maximum growth rate of top dry weight (W) at any time, was determined for rice plant. Using two rice varietal groups, japonica varieties and an indica $\times$ japonica "Dasanbyeo", 18 data points fulfilling the statistical criteria for determining Nc were obtained through eight N-fertilization experiments over two years at Suwon (37$^{\circ}$16'N), Korea. Nc dilution curve for each variety was obtained by fitting the Nc-W relationship to power function. However, The critical nitrogen curves for the two variety groups were not different statistically. Thus, a Nc dilution curve was fitted for the Nc data points pooled over the two variety groups and proposed in rice as: Nc=4.08, where W<1.73 t h $a^{-1}$ , Nc=5.197 $W^{0.425}$3/ ($R^2$=0.964), where 1.73 t h $a^{-1}$ <W<12 t h $a^{-l}$. The Nc for W<1.73 t h $a^{-l}$ were estimated as a constant value of 4.08%, the mean value of the maximum N concentration for N-limiting condition and the minimum N concentration for N non-limiting condition. The model for Nc is applicable to diagnosing the nitrogen nutrition status during the rice growth period from emergence to heading stage. The Nc curve well discriminated the 144 data points between the N limiting and the N non-limiting groups regardless of varieties, cultural methods, and years.-limiting groups regardless of varieties, cultural methods, and years.

Study of Chloride Corrosion Organic Inhibitors in Alkaline Pore Solution

  • Cabrini, M.;Lorenzi, S.;Pastore, T.;Pellegrini, S.
    • Corrosion Science and Technology
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    • v.17 no.5
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    • pp.203-210
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    • 2018
  • This paper compares the inhibition properties of aspartic and lactic acid salts with nitrite ions and their effect on critical chloride concentration. The tests were carried employing carbon steel specimens in saturated lime solution with varying pH in the range between13 to 13.6. The critical chloride concentration was estimated through multiple specimen potentiostatic tests at potentials in the usual range for passive rebar in the alkaline concrete of atmospheric structures. During tests, chloride salt was added every 48 h until all the specimens showed localized attacks. The cumulative distribution curves, i.e. the number of corroded specimens as a function of the chlorides concentration was obtained. Furthermore, IR spectra were recorded for the evaluation of the presence of the organic inhibitors on the passivity film. The results confirmed the inhibitory effect of 0.1M aspartate comparable with nitrite ions, at a similar concentration. Addition of calcium lactate did not result in an increase in the critical chloride concentration. However, the formation of a massive scale containing the substance that could reduce the corrosion propagation was observed.

An Experimental Study on the Effect of Fuel Dilution on the Propagation Velocity of Triple Flames in a Diverging Channel (연료희석이단면확대채널에형성된삼지화염의전파속도에미치는영향에관한실험적연구)

  • Seo, Jeong-Il;Shin, Hyun-Dong;Kim, Nam-Il
    • 한국연소학회:학술대회논문집
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    • 2007.05a
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    • pp.13-18
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    • 2007
  • When triple flames propagated in a diverging channel, the effects of fuel dilution on the lift-off characteristics of triple flames were investigated. A multi-slot burner was used to stabilize the lift-off flame especially at weak fuel concentration gradients. It was reported that there is a maximum propagation velocity at a critical concentration gradient in an open jet regardless of fuel dilution. The enhancement of a diffusion flame affected to increase the propagation velocity around critical concentration gradients. However, the influence of a confined channel on the structure of triple flames according to fuel dilution needs to be investigated compared with an open jet case. This study aimed to examine the effect of a confined channel on the structure and the propagation velocity of the triple flames according to fuel dilution. Lift-off height and propagation velocity of triple flames were investigated by employing three kinds of fuel compositions diluted by nitrogen (0%, 25%, 50% $N_2$), Fuel dilution reduced the propagation velocity of triple flame in a confined channel mainly due to the decrease of flame temperature in premixed branch. Despite the difference in fuel dilution, the propagation velocity has a maximum value at a specific fuel concentration gradient even though the critical concentration gradient increases with fuel dilution. And the critical concentration gradient in a confined channel is larger than that in an open jet due to enhancement of convective diffusion.

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