• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.307-312
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• 2003

The average frictional coefficient was used generally to analyze the moving state of lubricated machine. But It is difficult of getting the correct friction coefficient because the average frictional coefficient of it is progressed always unstably with a large amplitute on driving condition. If correct analysis of frictional coefficient on working condition for lubricated machine can be possible, it can be effect on diagnosis of lubricated machine. The purpose of this study is carried out to get the working condition with a minimum frictional coefficient of transmission gear materials using statistical techniques.

• Journal of the Korea Fashion and Costume Design Association
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• v.14 no.1
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• pp.111-121
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• 2012

This study focused on the plane and side drape coefficients of weft knitted fabrics as a function of knit structure, stitch density, and stiffness. Fifteen weft knitted fabrics are produced with five different structures (interlock, single pique, royal interlock, cross miss interlock, and mock royal interlock) and three different gauges (7G, 10G, and 12G). Five knit structures were the application of knit, tuck, and miss stitch on the basis of interlock of the double knit fabric For this purpose, three-dimensional shapes of the draped sample were obtained by using a drapability tester which can record the contour line coordinates of a projected plane drape. Then, projected shapes of the plane and side drape were derived from those three-dimensional ones to review the relationship between plane drape coefficients and side ones. It was found that the theoretical values of plane and side drape coefficients depending on the change of deflection angles fit to their experimental ones. A5 a result of a regression analysis of the relationship between plane and side drape coefficients, the relationship could be expressed as $y=0.5838x-0.0065x^2+9.03{\times}10^{-5}x^3$. In case of mean of drape coefficient, it was increased according to the rule of that the more tuck and miss stitch overlap. A high degree of correlation was found between stiffness and drape coefficient. The regression equation of drape coefficient($y$) can be represented by $y=y=\sqrt[3]{Stiffness}-10.72$.

• Honam Mathematical Journal
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• v.21 no.1
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• pp.139-147
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• 1999

In this paper we generalize the definition of strongly close-to-convex functions by using the functions g(z) of bounded boundary rotation and investigate the distortion and rotation theorem, coefficient inequalities, invariance property and inclusion relation for the new class $G_{k}[A,\;B]$.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.65-66
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• 2005

Anaerobic digestion is one of the well-known methods for biological treatment handling of concentrated organic matter such as swine $wastewater.^{1)} The anaerobic digestion can reduce organic loading but also hydrolyze non-biodegradable organic $matter.^{2)}$ The feces from the scrapper-type barn are usually collected to make compost and the urine is discarded with swine-slurry wastewater by ocean-dumping or treated by biological methods. The lagoon, aerobic digestion, anaerobic digestion, SBR, $A^{2}/O$, and UCT have been applied for treating swine $wastewater.^{3)} In this study, as a result of the analysis of swine wastewater, the total and soluble chemical oxygen demand was 130g/L and 60g/L, respectively. And the volatile fatty acid as chemical oxygen demand equivalent was 45g/L, which was 75% of soluble chemical oxygen demand. Before everything else, ammonia nitrogen concentration was 6.5 g/L. From biochemical acidogenic potential test, it was concluded that the enhanced acidification process to manage swine waste should be operated in the ammonia nitrogen concentration of less than 1.2 g/L. In the result of seeding ratio experiments with artificial $wastewater^{4)}, the lag period of acidogens was taken the long time because of the inhibition by the $ammonia^{5)}$, however no difference of period by the seeding ratio was not shown. The Haldane-based biokinetics were also evaluated using a method of fourth order Runge-Kutta $approximation.^{6,7)}$ The nonlinear least squares (NLLS) method with a 95% confidence interval was also used. The ranges of maximum microbial growth rate, ${/mu_{max}}$, and half saturation coefficient, $K_{s}$, for acidogenesis of various seeding ratio with artificial wastewater were 6.1 ~ 12.6 $d^{-1}$ and 45,000 ~ 53,500 mg glucose/L, respectively. Also, the methanogenic microbial yield coefficient, Y, and microbial decay rate coefficient, $k_{d}$, and inhibition substrate concentration, $K_{si}$, for the reactors were determined to be 0.32 ~ 0.465 ${/mu}g$/mg glucose; 0.42 ~ 1.01 $d^{-1}$ and 51,500 ~ 55,600 mg glucose/L, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.3
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• pp.254-261
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• 1988

Lysimeter and field experiments were conducted in Sandy Loam to establish a simple estimation model for evapotranspiration (ET) of soybean for three years (l984-1986). Potential ET (PET) could be estimated by the eq.1 using Pan-evaporation (Eo) and was ranged from 1.1 to 4.6 mm/day during the experiments. PET (mm/day)=1.348＋0.573 Eo …(1) Crop coefficient (Kc=maximum ET/PET) could be estimated by the eq.2 using Growth degree (G=days after planting/total growing days) and was ranged from 0.2 to 1.1 and from 0.6 to 1.4 for monoculture cropping and double cropping followed by barley, respectively, during the experiments. Monoculture : Kc=0.016＋3.719 G-3.224 G$^2$…(2), Double cropping : Kc=0.609＋2.014 G-2.120 G$^2$…(2). However, the maximum Kc was shown when G was about 50% and 40% for the monoculture and the double cropping, respectively. Soil water coefficient (f=AET/maximum ET) could be estimated by the eq.3 using soil water tension (Ψ) in 15cm depth. and it was decleased to 0.2 when Ψ was 10 bar. f=0.755-0.537 log │Ψ│…(3) Consequentially, the model to estimate the Actual ET (AET) of soybean was determined as eq.4 with the correction coefficient of -0.380. AET(mm/day)=PETㆍKcㆍf -0.380 …(4) The estimated AET were compared with the measured AET to verify the model established above. The average deviation of the estimated ET(AET) was 0.5782$\pm$0.338 (mm/day), and it would be within reasonable confidence range.

• Journal of Industrial Technology
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• v.20 no.A
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• pp.203-209
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• 2000

The fluctuation integrals which give useful information in the structure of solution are associated with the mixed direct correlation integral ($C_{12}$) known. Using its weighted arithmetic mean of $C_{11}$ and $C_{22}$ and the activity coefficient model, the fluctuation integrals on solute-solute, solvent-solute, and solvent-solvent can be calculated in the function of mole fraction. In this work, several binary mixtures containing c-hexane were tested and the results on the fluctuation integrals were rather good.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.253-258
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• 2001

Control of drag force on a circular cylinder using a detached splitter plate is numerically studied for laminar flow. A splitter plate with the same length as the cylinder diameter(d) is placed horizontally in the wake region. Its position is described by the gap ratio(G/d), where G represents the gap between the cylinder base point and the leading edge of the plate. The drag varies with the gap ratio; it has the minimum value at a certain gap ratio for each Reynolds number. The drag sharply increases past the optimum gap ratio; this seems to be related to the sudden change in the bubble size in the wake region. This trend is consistent with the experimental observation currently available in case of turbulent flow. It is also found that the net drag coefficient significantly depends on the variation of base suction coefficient.

• Journal of Environmental Health Sciences
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• v.27 no.4
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• pp.73-78
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• 2001

Hair will be persuit of beautifulness of human being in various permanent wave by many kinds of its drugs. Skin is based upon the hair which enroll the body of high living animals and have multiple membrane structure In this study used rat the effects of commercial permanent wave products to skin which are composed with L- cysteine and bases Results are as follow: the content of penetration 4 hors later with steady state and no significant changeable after 20 hours later. In cysteine groups, lag time and permeability coefficient of healthy skin is 2.22hr and 0.13$\mu\textrm{g}$/㎥ hr, lag time and permeability coefficient of old skin is 4.01 hr and 0.108 $\mu\textrm{g}$/㎥ hr . In conclusion of study lag time and permeability coefficient in old skin and wounded skin are faster than healthy skin. We notified that fine rinkle and rash of skin were changeable in the case of treating with permanent wave drugs than normal skin.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.412-414
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• 2015

유기 반도체의 전하 이동 특성은 그 구조적 특성에 매우 민감하다. 따라서 재료의 특성을 정확히 예측하기 위해서는 정확하게 구조를 모델링할 필요가 있다. 본 연구에서는 OLED에 널리 쓰이는 ${\alpha}$-NPD의 구조를 분자동역학을 통해 예측하기 위하여 OPLS-AA force field를 기반으로 하여 dihedral coefficient를 최적화하였다. DFT 계산을 기준으로 이를 근사하는 dihedral coefficient를 계산하였으며 ${\alpha}$-NPD의 중앙에 위치한 biphenyl dihedral의 경우, $K_2=2.74kcal/mol$, $K_4=-0.12kcal/mol$을 얻었다. 또한 이를 이용하여 melt-quench 방법을 통해 ${\alpha}$-NPD의 비정질 구조를 모델링하였다. 계산으로 얻어진 밀도는 $1.11g/cm^3$이며 실험값은 $1.12g/cm^3$이다.

• Journal of Korean Society on Water Environment
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• v.27 no.3
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• pp.329-333
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• 2011

p-phenylene-2,5-benzobisoxazole (PBO; Zylon$(R)$) fibers as an adsorbent were employed for solid phase extraction of aqueous alkylphenols. The removal ratios for 10 kinds of alkylphenols at initial concentration of $100{\mu}gL^{-1}$ were in the range of 16.8-96.3% and the removals increased with the increase of the phase ratio (fiber weight/solution volume). The plots of the logarithm of partition coefficient (log K) were correlated with the logarithm of the n-octanol/water partition coefficient (log P). The adsorbed alkylphenols were completely desorbed with the mixture of acetonitrile and dichloromethane.