• Journal of Astronomy and Space Sciences
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• v.32 no.2
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• pp.121-125
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• 2015

At the suggestion of the NASA Meteoroid Environment Office (NASA/MEO), which promotes lunar impact monitoring worldwide during NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) mission period (launched Sept. 2013), we set up a video observation system for lunar impact flashes using a 16-inch educational telescope at Chungnam National University. From Oct. 2013 through Apr. 2014, we recorded 80 hours of video observation of the unilluminated part of the crescent moon in the evening hours. We found a plausible candidate impact flash on Feb. 3, 2014 at selenographic longitude $2.1^{\circ}$ and latitude $25.4^{\circ}$. The flash lasted for 0.2 s and the light curve was asymmetric with a slow decrease after a peak brightness of $8.7{\pm}0.3mag$. Based on a star-like distribution of pixel brightness and asymmetric light curve, we conclude that the observed flash was due to a meteoroid impact on the lunar surface. Since unequivocal detection of an impact flash requires simultaneous observation from at least two sites, we strongly recommend that other institutes and universities in Korea set up similar inexpensive monitoring systems involving educational or amateur telescopes, and that they collaborate in the near future.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.2
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• pp.223-232
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• 1997

The accuracy and precision of a modified method of NIOSH Method 7600 and EPA method 218.6 was determined for analyzing hexavalent chromium, Cr(VI), collected on PVC filter from workplace air. The method was designed to extract from Cr(VI) on PVC filter with a alkali solution, 2% NaOH/3% $Na_2CO_3$, and to analyze it using ion chromatography/visible absorbance detection(IC/VAD). The results and conclusion are as the following. 1. The peak of Cr(VI) was separated sharply on chromatogram and was linearly related with Cr(VI) concentration in sloution. The correlation coefficient was 0.9999 in a calibration curve. The limit of detection was 0.25 $0.25{\mu}g/sample$. 2. The accuracy(% recovery) was 93.3% in a set of sample($9-50{\mu}g$) stored for a day, and 100.1%($10-60{\mu}g$) in another set of samples stored for 2 hours. It is assumed that the difference in recovery by storage time was due to reduction of Cr(VI) to Cr(III). 3. The precision(coefficient of variation, CV) of the method was 0.015 in spiked samples with Cr(VI) standard solution, and 0.010 in spiked samples with plating solution from a chrome electroplating factory. The overall CV in all types of samples was 0.0013. 4. The Cr(VI) was stable in 2% NaOH/3% $Na_2CO_3$ at least for 10 hours. In conclusion, the IC/VAD method is appropriate for determining low-level Cr(VI) in workplace air containing various interferences.

• The Journal of Internal Korean Medicine
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• v.14 no.1
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• pp.71-81
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• 1993

Clinical observation was done on 372 Cheon-Jeung patients more than 65 years of age in Department of Internal Medicine, Oriental Medical Hospital in Dong Guk Univ. from December 1990 to November 1991. The results were as follows; 1. The ratio of male to female was 1.2:1. The age distribution showed the large number in the 65-69 year group, the female more than the male in 8th decade. 2. The peak age in the on set was 7th decade(44.4%). 3. The ratio of the season distribution was as follows, everytime 62.6%, fall and winter 25.5%. 4. Duration from on set, the most frequence was $5{\sim}10$ years(29.6%). 5. Chief complaints were represented cough, laryngeal stridorand, dyspnea. 6. In past illness, Pulmonary. The was most predominent(29.7%) followed by allergic disease(8.1%), bronchitis(7.2%) in turn. 7. In complication, Pul. Tbc was most predominent(21.1%) followed by ronchiectasis (12.7), cardiac disease(11.3%). 8. Predisposing factors in the Geriatric athma were represented chiefly exercising(41.8%), the others is Pung-Han-Neng(27.6%), respiratory infection(12.7%) etc. 9. The recipe which used in treatment were Gamigeumsuyukgun-jeon, Gamimahwangyunpai-tang, Gamiyunpai-tang, Sojaganggi-tang, Cheongsangboha-tang etc. 10. Duration of treatment was noted within 10 days was 39.2%, $11{\sim}30$ days was 40.6%, over 60 days was 7.3%. 11. About 77.3% patients were improved.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.1
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• pp.27-32
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• 2014

This study analyzed the fundamental characteristics of concrete according to a ternary system mixing in order to reduce hydration heat of mass concrete and to improve early age strength. The results are as follows. The fluidity of unconsolidated concrete satisfied the target scope regardless of the binder conditions. When the replacement ratio between FA and BS increased, the slump of low heat-A mix and low heat-B mix increased, and air content was not affected by the change of binders. As for setting time, low heat cement mix had the fastest regardless of W/B, and high early strength low heat mix achieved 6 hours' reduction compared with low heat-B mix at initial set, and 12 hours' reduction at the final set respectively. As for the simple hydration heat, the low mix peak temperature was the highest and low heat-B mix had the lowest temperature. And high early strength low heat mix was similar with that of low heat-B. The compressive strength of hardened concrete had similar strength scope in all mixes except for low heat-B mix at early ages, and had unexceptionally similar one without huge differences at long-term ages.

• Culinary science and hospitality research
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• v.15 no.1
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• pp.149-156
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• 2009

This study was carried out to evaluate the effect of whey brew cultured by the mixed Lactobacillus helveticus ATCC 55163 and Propionibacterium acidipropionici 5020 on the rheological properties of flour dough. 10 and 15% of whey brews were added to the dough based on flour. Farinograph, alveograph, Rapid Visco Analyzer, and fermenting power of dough were analyzed. In the farinograph analysis, as the amount of whey brews increased on dough samples, water absorption, dough development time, stability, and breakdown increased. In the alveograph analysis, as the amount of whey brews increased on dough samples, P and W value increased while L and G value decreased. In the Rapid Visco Analyzer analysis, as the amount of whey brews increased on dough samples, initial pasting temperature and peak viscosity increased while final viscosity and setback decreased. Decrease of setback showed the delay of starch retrogradation. As the amount of whey brews increased on dough samples, fermenting power of dough got reduced.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4C
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• pp.533-540
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• 2004

This paper proposes a new multispectral image data compression algorithm that can efficiently reduce spatial and spectral redundancies by applying classified prediction, a Karhunen-Loeve transform (KLT), and the three-dimensional set partitioning in hierarchical trees (3-D SPIHT) algorithm in the wavelet transform (WT) domain. The classification is performed in the WT domain to exploit the interband classified dependency, while the resulting class information is used for the interband prediction. The residual image data on the prediction errors between the original image data and the predicted image data is decorrelated by a KLT. Finally, the 3-D SPIHT algorithm is used to encode the transformed coefficients listed in a descending order spatially and spectrally as a result of the WT and KLT. Simulation results showed that the reconstructed images after using the proposed algorithm exhibited a better quality and higher compression ratio than those using conventional algorithms.

• Korean journal of applied entomology
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• v.46 no.2
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• pp.287-293
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• 2007

The pollinating activity of bumblebee, Bombus ignitus was investigated at the blossom of Peach [Prunus persica (L.) Batsch] planted in vinyl house. The major time of foraging activity by B. ignitus was between 08:00 and 7:00, and the peak time of pollinating activity by B. ignitus was 11 :00 in the peach vinyl house from February 28 to March 5 in 2002. The rate of fruit set and the rate of marketable fruit by foraging activity of B. ignitus were much better than artificial pollination, and the effect of labor reduction by the pollinating activities of B. ignitus released against th ε artificial pollination was took remarkable profits over 93%. Therefore, the foraging activity of B. ignitus in peach vinyl house brought satisfactory results among the rate of fruit set, the rate of marketable fruit and the effect of labor reduction against the artificial pollination.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.3
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• pp.580-594
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• 2015

Liquid sloshing in two-dimensional (2-D) and three-dimensional (3-D) rectangular tanks is simulated by using a level set method based on the finite volume method. In order to examine the effect of natural frequency modes on liquid sloshing, we considered a wide range of frequency ratios ($0.5{\leq}fr{\leq}3.2$). The frequency ratio is defined by the ratio of the excitation frequency to the natural frequency of the fluid, and covers natural frequency modes from 1 to 5. When fr = 1, which corresponds to the first mode of the natural frequency, strong liquid sloshing reveals roof impact, and significant forces are generated by the liquid in the tank. The liquid flows are mainly unidirectional. Thus, the strong bulk motion of the fluid contributes to a higher elevation of the free surface. However, at fr = 2, the sloshing is considerably suppressed, resulting in a calm wave with relatively lower elevation of the free surface, since the waves undergo destructive interference. At fr = 2, the lower peak of the free surface elevation occurs. At higher modes of $fr_3$, $fr_4$, and $fr_5$, the free surface reveals irregular deformation with nonlinear waves in every case. However, the deformation of the free surface becomes weaker at higher natural frequency modes. Finally, 3-D simulations confirm our 2-D results.

• Clinics in Shoulder and Elbow
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• v.12 no.2
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• pp.207-214
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• 2009

Purpose: In arthroscopic rotator cuff repairs there are generally weak link in tendon suture interface, arthroscopic rotator cuff repairs can have higher retear rates than open repairs. The purpose of this study was to compare the strength of UU (Ulsan University) suture than open modified MA (Mason-Allen) suture when suture anchored into bone. Materials and Methods: The human supraspinatus tendons were harvested from the shoulder of the cadaver and split in 2 times, producing four tendons per one shoulder, for a total of 24 specimens. Two suture configurations (UU, MA) were randomized and checked on each set of tendons. Specimens were cyclically loaded under force control between 5 and 30 N at 0.25 Hz for fifty cycles. Each specimen was loaded to failure under displacement control at 1 mm/sec. Cyclic elongation, peak to peak displacement, stiffness, ultimate tensile load, mode of failure were checked. Results: No significant difference was found between two suture configuration with respect to peak to peak displacement, cyclic elongation, and stiffness. With regard to ultimate failure load, there were no significant difference statistically between the UU suture and modified MA suture (109.4 N, 110.6 N). The most common mode of failure between both sutures was suture pull-out through the tendon. Conclusion: The UU suture and modified MA suture produced similar biomechanical properties.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.411-417
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• 2014

Special Protection Scheme(SPS) for generator tripping action is an emergency control tool that secures the power system stability by instantly tripping the pre-determined number of generators to avoid the acceleration of the remaining generators in a large-scaled power plants when a fault occurs on the drawing transmission lines. However, since the existing operating conditions of SPS are set based on a peak demand, SPS could trip more generators than required if it is activated during the off-peak demand period. For this, this paper proposes the algorithm for setting the operating conditions of SPS through the online stability evaluation with the periodically updated operating conditions of power systems. The proposed algorithm adopts COA for the accuracy and speed of the stability evaluation, and can reduce the number of tripping generators by SPS during the off-peak demand period. This results in reducing the loss of profit caused by a fault on power systems.