• Journal of the Korean Society of Tobacco Science
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• v.28 no.1
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• pp.43-50
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• 2006

The objective of the present study is to induct the regression equation for the hardness prediction of cellulose acetate filter which was manufactured by the domestic cellulose acetate tow manufacturer. As a result of our study, the hardness of filter was increased with increasing the plasticizer content and packing density as major factors affecting to the filter hardness. As a result which was obtained by the three dimensional response surface methodology in STATISTIC A program, the hardness prediction value well fitted with experiment result on the high plasticizer content. To make up for the this equation, the new modified fraction of solid factors which was contained the mono denier factor was introduced to the hardness prediction equation, and this third regression equation which was sufficient for the wide plasticizer content, was obtained by the three dimensional response surface methodology in STATISTICA. This results indicated that the third regression equation which was obtained this study was applicable for the hardness prediction of cellulose acetate filter which was manufactured by the domestic cellulose acetate tow manufacturer.

• Journal of Chest Surgery
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• v.22 no.2
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• pp.179-190
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• 1989

The experimental study for extracorporeal preservation of the heart-lung preparation by autoperfusion system was performed in 10 dogs. Under intravenous Pentothal endotracheal anesthesia bilateral thoracotomies were performed. A 24F cannula connected to a plastic reservoir bag located 100 cm above the level of the heart was introduced into the aortic arch. Left subclavian, innominate artery, and descending aorta were ligated and divided. Both vena cavae were ligated and divided after the bag was half filled with blood. A 24F catheter inserted into right atrium and connected to the plastic bag in order to keep constant the preload. The thoracic trachea was intubated and the lungs were ventilated. The heart-lung preparations were removed en bloc and floated in a $34^{\circ}C$ bath of Hartmann solution. The preparations were observed for from 2 hours to 8 hours, with the average of 5.2 hours. Hemodynamic and hematologic variables were measured during preharvest and autoperfusion. The pH revealed severe respiratory alkalosis due to very low $PaCO_2$ during autoperfusion ; $PaO_2$ remained constant for 130-140 mmHg; $A-aDO_2$ increased markedly. The static inspiratory pressure [SIP] at late autoperfusion [6hr] increased significantly as compared with at early autoperfusion [2hr]. There was no difference between white blood cell counts from right atrium and those of left atrium. Heart rates remained constant for 110-120/min; cardiac outputs maintained to approximately 0.6L/min; mean aortic pressures, 75 mmHg; mean pulmonary arterial pressures, 15-18 mmHg; mean right atrial pressures, 9-13 mmHg; mean left atrial pressures, 12 mmHg lower than those of right atrium. Serum Na maintained with normal range during autoperfusion; K increased significantly; Ca decreased progressively. Hemoglobin and hematocrit decreased significantly during autoperfusion. The study demonstrated that stable hemodynamics could be maintained throughout the experiment and the preparation of the lung seemed to be inadequate, especially after 3-4 hours, such as high $A-aDO_2$, increased SIP, and scattered atelectasis and edema in their gross appearances.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.10
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• pp.65-72
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• 1998

The BTA drilling chip is better for deep hole drilling than other self-piloting with pad drilling chips because the large length to diameter ratio allows a unique cutting force dispersion and better supplies the high pressure fluid. Therefore the BTA is useful for many tasks, such as coolant hole drilling of large scale dies, as well as tube seat drilling, which is essential for the heat exchanger, and variable component drilling for automobiles. Deep hole drilling has several significant problems, such as hole deviation, hole over-size, circularity, straightness, and surface roughness. The reasons for these problems, which often result in quality short comings, are an alignment of the BTA drilling system and the unbalance of cutting force by work piece and tool shape. This paper analyzes the properties through an experiment which com¬pared single-edge BTA drills with multiple-edge BTA drills, as well as the shapes of the tools to cause an unbalance of cutting force, and its effect on the precision of the worked hole. Conclusions are as follows. 1) In SMSSC drilling, 60m/min of BTA with single and multi-edged tools proved the best cutting condition and the lowest wear character. 2) The roundness got a little worse as cutting speed was increased, but surface roughness was hot affected. 3) It was proved that the burnishing torque of both drills approached 26%. which is almost the same as the 24% insisted on by Griffiths, and the dispersion characteristic of the multi-edged BTA drill proved better than the single-edge BTA drill.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.6
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• pp.1622-1628
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• 2005

This study was undertaken to define the effect of SoPung-Tang extract on hypertension in spontaneous hypertensive rat and norepinephrine- induced arterial contraction in rabbit. In order to investigate the effect of SoPung-Tang extract on contracted rabbit carotid arterial strips, transverse strips with intact or damaged endothelium were used for the experiment using organ bath. To analyze the mechanism of SoPung-Tang extract-induced relaxation, SoPung-Tang extract infused into contracted arterial strips induced by norepinephrine after treatment of indomethacin, Nu-nitro-L-arginine, methylene blue or tetraethylammonium chloride. Blood pressure was significantly decreased five days after administration of SoPung-Tang extract. SoPung-Tang extract relax arterial strip with endothelium contracted by norepinephrine, but in the strips without endothelium, SoPung-Tang extract- induced relaxation was significantly inhibited. SoPung-Tang relax arterial strip contracted by norepinephrine, but in the strips contracted by high $K^+$, SoPung-Tang extract-induced relaxation was significantly inhibited. The endothelium-dependent relaxation induced by SoPung-Tang extract was decreased by the pre-treatment of $N{\omega}$-nitro-L-arginine or methylene blue, but it was not observed in the strips pre-treated with indomethacin or tetraethylammonium chloride. When $Ca^{2+}$ was applied, the strips which were contracted by norepinephrine in a $Ca^{2+}$-free solution, arterial contraction was increased. But pre-treatment of SoPung-Tang extract inhibited contractile response to $Ca^{2+}$. We suggest that SoPung-Tang could be applied effectively for hypertension and may suppress influx of extra-cellular $Ca^{2+}$ through the formation of nitric oxide in the vascular endothelial cells.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.310-316
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• 2006

In this study, activated carbon in a powder form was used to remove dissolved ammonia which causes a fouling smell in water. Since the adsorption capacity of common powder activated carbon is not high enough, we prepared powder activated carbon deposited on an acid solution to enhance the adsorption capacity. The acid-impregnated activated carbon was applied on the surface of porous fibril support ($10{\sim}50{\mu}m$) by which adsorption and separation processes take place simultaneously by varying effective pressure. As the result, the ammonia removal efficiency is above 60% in the mixing process which is 10~15% higher than general powder activated carbon. From the result of an experiment on the pure permeable test of a dynamic membrane, its transmittance is 400~700 LMH (liter per hour), indicating that the prepared membrane works as a microfiltration membrane. Therefore, it is expected that the membrane prepared in this way would improve the efficiency of water treatment than conventional membranes.

• Korean Journal of Crystallography
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• v.1 no.1
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• pp.19-28
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• 1990

6H-SiC is a promising material (Eg=3.0eV) for blue light-emitting doide and high-temperature semiconducting device. In the experiment, single crystals of a-SiC have been grown by the sublimation method to fabricate blue light~emitting diode. During the growth of a-SiC single crystals, a temperature Vadient, yonh temperature and pressure ranges were kept 44℃/cm , 1800-1990℃ and 50-1000 mTorr, respectively. Single crystals obtained in Acheson furnace were used as seed crystals. Polarizing microscopy and back-reflection X-ray Laue diffraction showed that the a-SiC crystal was epitaxially and on the seed crytal. It was found by XRD analysis that when other growth conditions were the same, a-SiC was grown at the temperature above 1840℃ and 3C-SiC was gown at lower temperature or under low supersaturation of vapor. The carrier type. concentration and mobility were measured be hole(p-type), 7.6x1014cm-3 and 19cm2V-1sec-1, respectively, by van der Pauw method.

• Fire Science and Engineering
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• v.25 no.6
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• pp.51-57
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• 2011

The domestic wooden cultural properties applied to the sprinkler extinguishing system was confirmed extinguishing performance through fire experiments. Consists of wooden cultural properties of a fire, a flammable material is vulnerable in terms of. The scale of fire will occur to vary appearance of the initial fire in case of arson. Sprinkler nozzles of the characteristics, the discharging pressure is 1 bar and the flow rate is 80 lpm, applied in this experiment. Fire performance experiments were tested in two separated in each of the scale of the fire and cultural properties. Fire extinguishing performance test results was low in high ceilings and two or more units of the fire scale. Fire growth environment of the actual wooden cultural properties to experimental models when you consider that it is more vulnerable, sprinkler extinguishing system is required sufficient verification in order to apply fire protection of the wooden cultural properties.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.4
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• pp.281-286
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• 2004

The wear process of end mill is a so complicated process that a more reliable technique is required for the monitoring and controling the tool life and its performance. This research presents a new tool wear monitoring method based on the sound signal generated on the machining. The experiment carried out continuous-side-milling for using the high-speed steel end mill under wet condition. The sound pressure was measured at 0.5m from the cutting zone by a dynamic microphone, and was analyzed at frequency domain. The tooth passing frequency appears as a harmonics form, and end mill wear is related with the first harmonic. It can be concluded from the result that the tool wear is correlate with the intensity of the measured sound at tooth passing frequency estimation of end mill wear using sound is possible through frequency analysis at tooth passing frequency under the given circumstances.

• Journal of Drive and Control
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• v.12 no.1
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• pp.1-8
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• 2015

The stability of friction characteristics and thermal management for a dry type dual clutch transmission (DCT) are inferior to those of a wet clutch. Too high temperature resulting from frequent engagement of DCT speeds up degradation or serious wear of the pressure plate or burning of the clutch disk lining. Even though it is significantly important to estimate the temperature of a dry double clutch (DDC) in real-time, few meaningful study of the thermal model of DDC has been known yet. This study presented a thermal analytical model of lumped parameters for a DDC by analyzing its each component firstly. Then a series of experimental test was carried out on the test bench with a patented temperature telemetry system to validate the proposed thermal model. The thermal model, whose optimal parameter values were found by optimization algorithm, was also simulated on the experimental test conditions. The simulation results of DDC temperature show consistency with the experiment, which validates the proposed thermal model of DDC.

• Korean Journal of Oriental Medicine
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• v.10 no.2
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• pp.79-92
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• 2004

Objectives : This experiments were performed to determine the effect of OYakSoonGi-San extract on hypertension in spontaneous hypertensive rat and norepinephrine-induced arterial contraction in rabbit. Methods : In order to define the effect of OYakSoonGi-San extract on contracted rabbit carotid arterial strips, transverse strips with intact or damaged endothelium were used for the experiment using organ bath. To analyze the mechanism of OYakSoonGi-San extract-induced relaxation, OYakSoonGi-San extract infused into contracted arterial strips induced by norepinephrine after treatment of indomethacin, $N{\omega}-nitro-L-arginine$, methylene blue or tetraethylammonium chloride. Results : Blood pressure was significantly decreased five days after administration of OYakSoonGi-San extract. The relaxation effect of OYakSoonGi-San extract was dependent on the presence of endothelium, showing that OYakSoonGi-San extract-induced relaxation was not observed in the strips without endothelium. Also OYakSoonGi-San extract-induced relaxation was significantly inhibited in arterial strips which were contracted by high $K^+$. OYakSoonGi-San extract-indeced relaxation was significantly inhibited by the pre-treatment of $N{\omega}-nitro-L-arginine$ or methylene blue, but it was not observed in the strips pre-treated with indomethacin or tetraethylammonium chloride. When additive application of $Ca^{2+}$ in arterial strips which were pre-contracted by norepinephrine in a $Ca^{2+}$-free solution, arterial contraction was increased. But contractile response to $Ca^{2+}$ was attenuated by pre-treatment of OYakSoonGi-San extract. Conclusions : These results demonstrated that OYakSoonGi-San could be applied effectively to hypertension and may inhibit agonist-induced contraction through an decrease influx of extra-cellular $Ca^{2+}$ by the formation of nitric oxide in the vascular endothelial cells.