• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.923-930
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• 2008

The butterfly valve is widely used in the industrial field as an on-off or a flow control valve. When the butterfly valve is used as a flow control valve. cavitation sometimes occurs in the range of high flow rate because of the small valve opening. Therefore. the pressure loss and the cavitation characteristics are investigated by use of a commercial CFD code. The results show that the possibility of cavitation occurrence in the cryogenic butterfly valve is very high in the case of valve opening angle below 10 degree and incident velocity over 6m/s. By increasing the inlet velocity at 10 degree of valve opening angle. the value of loss coefficient increased. However. by increasing the inlet velocity at 50 degree of valve opening angle. the value of loss coefficient decreased.

• The Journal of Pediatrics of Korean Medicine
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• v.17 no.2
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• pp.1-13
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• 2003

Objectives: The purpose of this study was to suggest a scientific method for measurement of children's growth development. Ultrasonic image of calcaneus bone has some advantages that it is harmless to human body and apply a new imaging analysis algorithm. it can be used for the diagnosis of growth analyzed the opening degree of growth plate and bone density. Methods: This clinical study have been carried out with the 57 case(male 24, female 33) of the children aged 5 to 14 years old who visited in Department of Pediatrics, Dongguk university Bundang Oriental Hospital. Bone maturity is measured by the opening degree of growth plate and bone density in ultrasonic image of calcaneus bone This study were designed to investigate the relationship of the development of children and the calcaneus bone maturity. Result: The opening degree of growth plate was no change in aged 5-10 years for male and 5-9 years for female but decreased significantly from aged 11 years for male and 10 years for female. the bone density was no change in aged 5-12 years for male and 5-11 years for female but increased significantly from aged 13 years for male and 12 years for female. it was confirmed that bone maturity in female is more rapid than in male. The opening degree of growth plate of claclneus bone was correlated with age, height, weight. The bone density was correlated with age, height, weight, BMI in this suudy(P<0.001) Conclusion: The opening degree of growth plate and bone density of calcaneus bone are sufficient diagnostic worth as an index to predict adolescent growth.

• Journal of the East Asian Society of Dietary Life
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• v.3 no.2
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• pp.107-119
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• 1993

The objeative of this study was to investigate the possibility of estimation of internal quality by observing visible state of strawberry. Several tests such as color("L", "A", H,V,C), degree of blackred ness, opening state of calyx, vitamin C content, brix degree, acidity, freshness, overall quality, chlorophyll content, and anthocyanin content were performend during circulation at 20$^{\circ}C$. Acidity(R=-0.96), chloroph-yll content(r=-0.99), vitamin C content(r=-0.98), freshness(r=-0.96), and overall quality(-0.99), degree of blackredness(r=0.98) and opening state of calyx(=0.98), color saturation(r=0.99), degree of blackredness(r=0.98) and opening state of calyx(=0.98) increased during circulation at 20$^{\circ}C$. in correlation between visible indicators andd internal qualities, "L" valu and brix degree was r=-0.74, "a" and brix degree was r=0.93 Hue and anthocyanin content was r=0.74, value and chlorophyll content, brix degree were r=-0.91, r=-0.77, chroma and brix degree was r=0.96. The correlations between color saturation and vitamin C content(r=-0.96), chlorophyll content(r=-0.98), freshness(r=-0.98), overall quality(r=-0.94), loss of total polyphenol(0.94) and acidity(r=-0.94) showed high correlation. The correlatiions between degree of blackrednes and vitamin C content(r=-0.99), chlorophyll content(r=-0.94), anthocyanin content(=-0.74), freshness(r=-0.97) overall quality (r=-0.95), loss of total polyphenol(r=0.93) and acidity(r=-0.91) chlorophyll content(r=-0.99), freshness(r=-0.98), overall quality(r=-0.92), loss of total polyphenol(r=0.99) and acidity(r=0.83) showed high correlation.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.322-327
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• 2000

Natural convection heat transfer in an enclosure with an opening in the right vertical wall and a heat source at the bottom surface is investigated using a holographic interferometric technique. The effects of the opening length, divider length attached to the top wall, and heater temperature on the temperature distribution are examined. The openging length as well as the divider length greatly affects the degree of inflow and outflow of air. With a small opening, the opening doesn't affect much the upward warm air flow resulting in the symmetric temperature distribution. On the other hand, with the increase of the opening length, the inward cold flow moves the upward flow to the left direction. With the increase of the divider length, temperature in the lower region of enclosure becomes higher for the small opening and lower for the large opening.

• Polymer(Korea)
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• v.30 no.4
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• pp.357-361
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• 2006

Alpha-lipoic acid (ALA) synthesized in the body has virtues such as anti-oxidation, blood sugar regulation, appetite suppression, and anti-obesity, etc. ALA, which is also used as a drug, has a five-membered ring including disulfide and so easily losses bioavailability due to ring opening and subsequent polymerization by heat or ultraviolet. This report studies various conditions for ring opening polymerization. The ring opening starts above the melting point of ALA, but there was no temperature dependence above it. At $70^{\circ}C$, the degree of ring opening was proportional to reaction time and inversely proportional concentration. The degree of ring opening in acetic acid with UV for 1 hour reached the maximum conversion (70%). Most cleaved ALA changed into disulfide polymers, and the molecular weight of the polymers increased as the amount of ring opening increased.

• Journal of Environmental Science International
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• v.15 no.12
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• pp.1109-1117
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• 2006

To investigate the influence of the mesophyll cells on stomatal opening in response to white light, the segments of isolated epidermis were transferred on partly exposed mesophyll cells of a leaf and stomatal apertures were measured. Transferring the isolated epidermis on partly exposed mesophyll cells of a leaf caused a marked increase on stomatal apertures while stomata in isolated epidermis incubated in MES buffer hardly opened. Mesophyll infiltration with photosynthetic inhibitors (DCMU, DCCD, $NaN_3$) was performed to elucidate the correlation between stomatal apertures and the degree of photosynthetic activity. It was found that transferring the isolated epidermis on partly exposed mesophyll cells of a leaf caused an increase of stomatal apertures depending on the degree of photosynthetic activities. In $NaN_3$ infiltrated leaf discs, transferring the fresh isolated epidermis on partly exposed mesophyll cells of a leaf showed no significant effect, but a slight increase on stomatal apertures. Isolated epidermis alone did not respond to the light properly, but if it was closely contacted with mesophyil cells, the stomata regained the ability of the light response. Therefore, it could be suggested that stomatai apertures were related with the degree of photosynthetic activity in the mesophyll cells.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4122-4126
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• 2012

Cellulose-graft-poly (L-lactide) (cellulose-g-PLLA) was successfully prepared via ring-opening polymerization (ROP) by using 4-dimethylaminopyridine (DMAP) as an organic catalyst in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). The structure and morphology of the polymer was characterized by nuclear magnetic resonance (NMR) and transmission electron microscope (TEM). From wide-angle X-ray powder diffraction (WAXD) and degradation test (by acid, alkaline, PBS and enzyme solution), changes in the crystalline structure as a result of degradation was also investigated. The results indicated that materials which have low degree of crystallinity showing higher degradability, however, in acid liquor, enzyme solution, alkaline liquor and PBS system, the degradation rate of the polymer decreased by the above sequence. Moreover, with the further increase of graft degree of this material, its degradation degree decreased.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.3
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• pp.1-11
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• 1993

An experimental study was carried out to evaluate the characteristics of transient performance of carburettered gasoline engine under rapid accelerating transient driving conditions. In order to evaluate the characteristics of transient performance quantitatively, the concept of dead time $t_d$ response delay time $t_r$ are introduced. Performance parameters such as air mass fiowrate Gat, engine speed N, manifold boost pressure Pb, and output torque T are measured simultaneously during the rapid opening of the throttle valve by the stepping motor. During the rapid opening of the throttle valve, air mass fiowrate Gat is increased immediately without delay time, but response of engine revolution N, and output torque T are delayed. Therefore hesitation, and stumble phenomena are occurred. Dead time $t_d$ and response delay time $t_r$ of engine revolution N, which is extremely delayed comparing to other performance parameters, are respectively 0.2-0.3sec., 3.0-4.6sec., and dead time rate $t_d/{\Delta}t$ and response delay time rate $t_r/{\Delta}t$ are linearly increased with the throttle valve opening rate ${\theta}$ during the acceleration from 12 degree to 20 degree at 1250rpm.

• Journal of Korean Society on Water Environment
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• v.38 no.1
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• pp.1-9
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• 2022

The Yeongsan River, one of the four major rivers in Korea, shows the highest degree of water pollution compared to the other major rivers. The construction and opening of two weirs, Seungchon and Juksan, induced fluctuations in the hydrologic conditions and water quality of the river. To investigate the water quality changes caused by the opening of the weir in 2017, this study analyzed the water quality data using the non-parametric Wilcoxon signed-rank test and the three-dimensional spatiotemporal plots. The non-parametric statistical test results showed that the concentration of all parameters has increased after 2017 at a significance level of 0.05. For the parameters that showed the highest degree of change, chlorophyll-a and suspended solids, the median values have increased by more than 30% after weir opening. Visual analysis additionally showed the spatial changes in the Yeongsan River. Generally, the sites above the Seungchon weir showed higher pollution levels than those above the Juksan weir. In time series, visual analysis results also showed the trend of rising concentration for all water quality parameters, indicating that the opening of two weirs had a significant effect on the change in water quality of the Yeongsan River.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.319-330
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• 1995

This study was designed to evaluate the interrelationship between the condylar head position in transcranial view and the articular disc position in the arthrography. The condylar positions were assessed by subjective method and linear measurement method on the transcranial view. The subjects for this study consisted of 24 symptomatic joints with normal disc position, 37 joints with anterior disc displacement with reduction and 44 joints with anterior disc displacement without reduction that were classified by arthrotomography under the fluoroscopic guidance. The interrelationship between the condylar head position in transcranial view and the articular disc position in the arthrography was evaluated by Chi square test. The obtained results were as follows : 1. There was no significant interrelationship between the position of condylar head in closed mouth state on transcraniaJ view and articular disc position in the arthrography (p>0.05). 2. There was no significant interrelationship between the changes of interarticular distance in 1 inch opening state and articular disc position in the arthrography (p>0.05). 3. There was no significant interrelationship between the position of condylar head related to the apex of articular eminence in 1 inch opening state and articular disc position in the arthrography(p>0.05). 4. There was significant interrelationship between the changes of interarticular distance that is assessed by linear measurement method in maximum opening state and articular disc position in the arthrography(p<0.05), but there was no significant interrelationship when the condylar head position was assessed by subjective method(p>0.05). 5. There was significant interrelationship between the degree of condylar translation in maximum opening state and articular disc position in the arthrography(p<0.05). 6. The correlation coefficient between two methods to assess the position of condylar head were 0.7989: the condylar head position in articular fossa in closed state, 0.6847: interarticular space in 1 inch opening state, 0.8965: the degree of condylar translation in 1 inch opening state, 0.5944: the changes of interarticular space in maximum opening state, 0.9215: the degree of condylar translation in maximum opening state.