• River and Culture
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• v.6 no.4
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• pp.82-87
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• 2010

• Journal of the Korean Chemical Society
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• v.63 no.6
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• pp.512-512
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• 2019

• Applied Chemistry for Engineering
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• v.26 no.4
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• pp.432-438
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• 2015

In this work, activated carbon fibers (ACFs) were oxyfluorinated and their adsorption ability for the low concentration of hexavalent chromium in an aqueous solution was investigated. The pore structure and surface properties of ACFs were examined by BET and X-ray Photoelectron Spectroscopy (XPS), respectively. Due to the oxyfluorination treatment, the content of (C-O) bond on ACFs surface which influences the adsorption capacity for heavy metal ions increased largely, resulting that $Cr^{6+}$ adsorption equilibrium reached quickly within 10 min. In addition, the maximum removal efficiency at the initial $Cr^{6+}$ concentration of 20 ppm was observed, which is a 100% improvement compared to that of non-treated ACFs. These results suggest that the oxyfluorination of ACFs can be applied as a good surface treatment for the effective adsorption of the low concentration of $Cr^{6+}$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.11
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• pp.450-457
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• 2016

While many studies on the heat transfer effect of an impinging jet have been published, most studies focus on the downward impinging jet. This study investigates the impinging jet heat transfer phenomenon when water at a temperature of $24^{\circ}C$ impinges on the downward isothermal circular plate at 60, 70, and $80^{\circ}C$ and when the upward round jet nozzle is 4, 6, and 8 mm diameter with a flow rate 3.6, 4.6, and 5.6 L/min, respectively, and when the ratio of the nozzle clearance/nozzle diameter (H/D) is 1. The results showed that, as the nozzle diameter decreases, the heat transfer coefficient increases at a constant flow rate. The correlation equation of $Nu_r$, $Pr_r$, and $Re_{jg}$ is obtained in the impinging and constant velocity flow region $(Nu_r/Pr^{0.4}_r)Dr=4.6[Re_{jg}(r/R_c)Dr]^{0.8}$ at all flow rates, in the deceleration and falling flow regions $(Nu_r/Pr^{0.4}_r)Dr=42.7{\mid}Re_{jg}(r/R_c)Dr-345.7{\mid}^{0.3}$ at 3.6 L/min, $(Nu_r/Pr^{0.4}_r)Dr=92.4{\mid}Re_{jg}(r/R_c)Dr-16.8{\mid}^{0.2}$ at 4.6 L/min, and $(Nu_r/Pr^{0.4}_r)Dr=322.4{\mid}Re_{jg}(r/R_c)Dr-536.2{\mid}^{0.01}$ at 5.6 L/min.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.6
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• pp.776-782
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• 2004

Generally, Max-Min CRI (Compositional Rule of Inference ) method by Zadeh and Mamdani is used in the conventional fuzzy inference. However, owing to the problems of Max-Min CRI method, the inference often results in significant error regions specifying the difference between the desired outputs and the inferred outputs. In this paper, I propose a New Max-Min CRI method which can solve some problems of the conventional Max-Min CRI method. And then this method is simulated in a D.C.series motor, which is a bench marking system in control systems, and showed that the new method performs better than the other fuzzy inference methods.

• Korean Journal of Clinical Laboratory Science
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• v.39 no.1
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• pp.25-30
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• 2007

In this study, the two sampling methods for blood glucose measurement were evaluated in order to reduce pre-analytical error. For this purpose, glucose levels of Li-heparinized plasma (LHP) and Na-fluorinated plasma (NFP) in blood collected from healthy volunteers were determined by using routine hexokinase procedures. The percentage range of pre-analytical error was quantitated by comparing LHP glucose values with NFP glucose values according to delaying analytical time (0, 60, and 120 min). LHP glucose values were decreased by 6.6% in 60 min., 17.7% in 120 min, whereas NFP glucose values decreased by 1.1% in 60 min, 2.0% in 120 min. Therefore it may be recommended that the NFP sampling method should be used for routine blood glucose determination in diabetes mellitus diagnosis.

• Korean Membrane Journal
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• v.9 no.1
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• pp.12-17
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• 2007

We performed periodic water-back-flushing using permeate water to minimize membrane fouling to enhance permeate flux in tubular ceramic microfiltration system for water treatment of high turbid source. The filtration time (FT) = 2 min with periodic 6 sec water-back-flushing showed the highest value of dimensionless permeate flux ($J/J_o$), and the lowest value of resistance of membrane fouling ($R_f$), and we acquired the highest total permeate volume $(V_T)\;=\;6.805L$. Also in the result of BT effect at fixed FT = 10 min and BT (back-flushing time) = 20 sec showed the lowest value of $R_f$ and the highest value of $J/J_o$, and we could obtain the highest $V_T\;=\;6.660\;L$. Consequently, FT = 2 min and BT = 6 sec could be the optimal condition in water treatment of high turbid source above 10 NTU. However, FT = 10 min and BT = 20 sec was superior to reduce operating costs because of lower back-flushing frequency. Then the average quality of water treated by our tubular ceramic MF system was turbidity of 0.07 NTU, $COD_{Mn}$ of 1.86 mg/L and $NH_3-N$ of 0.007 mg/L.

• Journal of Chest Surgery
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• v.28 no.10
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• pp.885-891
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• 1995

In order to test the hypothesis that the pulmonic valve, when used to replace the aortic root as a pulmonary autograft, will remain a viable anatomical structure and will grow and develop normally along with the host, we performed aortic valve replacement with the pulmonary autograft in 15 neonatal piglets. The weight of the donor was 9.3 $\pm$ 0.2 kg, the recipient 9.6 $\pm$ 0.3 kg. Measured diameters of pulmonic annulus were 14 $\pm$ 0.2 mm for autograft and 14.2 $\pm$ 0.2 mm for pulmonary artery homograft. Operation was performed under cardiopulmonary bypass with deep hypothermia [20oC at low flow perfusion [70 ml/kg/min . The mean operation time was 227 $\pm$ 10 min., bypass time 152$\pm$ 7.6 min. and aortic cross clamp time 73$\pm$ 4.6 min.. 9 piglets survived more than 12 hours. One survived 12 days and died of pneumonia and the latest one survived in good condition and sacrificed at postoperative 6th week for cardiac catheterization and pathologic examination that revealed the viability and growing of the pulmonary autograft. Currently we are able to complete the operation with good preservation of cardiac function, and our postoperative care has evolved to the extent that we are now confident enough of having an acceptable percentage of long term survivors to undertake a definite study in this regard.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.348-358
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• 2005

This paper showed mechanical properties and behaviors of macrostructures for specimens welded by F.S.W according to welding conditions and tool with 6.35$mm_t$ aluminum 7075-T651alloy plate. It resulted in defect-free weld zone in case tool rotation speed was 800rpm, 1250rpm and 1600rpm respectively that transition speed was changed to 15mm/min, 61mm/min and 124mm/min with tool's pin diameter 4${\Phi}$mm and 6${\Phi}$mm. The optimum mechanical property, ultimate stress,${\sigma}_Y$=470Mpa was obtained at the condition of 124mm/min of travel speed with 800rpm of tool rotation speed using full screw type pin, shoulder dia. 20${\Phi}$mm, pin dia.6${\Phi}$mm and pin length 6mm. The full-screw type and the half-screw type pin showed the similar behaviors of weldability. It is found that the size of nugget was depended on tool transition speed and tool dimension by macrostructures of the cross section of weld zone.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.6
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• pp.872-877
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• 2017

Objective: In order to utilize fat from broiler byproducts efficiently, it is necessary to develop an appropriate rendering procedure and establish quality information for the rendered fat. A study was therefore undertaken to evaluate the influence of rendering methods on the amounts and general properties of the fat recovered from broiler skin. Methods: The yield and quality of the broiler skin fat rendered through high and lower energy microwave rendering (3.6 W/g for 10 min and 2.4 W/g for 10 min for high power microwave rendering (HPMR) and high power microwave rendering (LPMR), respectively), oven baking (OB, at $180^{\circ}C$ for 40 min), and water cooking (WC, boiling for 40 min) were compared. Results: Microwave-rendered skin exhibited the highest yields and fat recovery rates, followed by OB, and WC fats (p<0.05). HPMR fat had the highest $L^{\star}$, $a^{\star}$, and $b^{\star}$ values, whereas WC fat had the highest moisture content, acid values, and thiobarbituric acid (TBA) values (p<0.05). There was no significant difference in the acid value, peroxide value, and TBA values between HPMR and LPMR fats. Conclusion: Microwave rendering at a power level of 3.6 W/g for 10 min is suggested base on the yield and quality of chicken fat.