• Elastomers and Composites
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• v.43 no.3
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• pp.157-165
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• 2008

Suspension polymerization was carried out to synthesize poly(butyl methacrylate) (PBMA) composite particles containing carbon black. Water was selected as a reaction medium, hydrophobic silica as a stabilizer and azobisisobutyronitrile as an initiator. Concentration of stabilizer was varied from 0.67 to 2.55 weight% with respect to the water, and that of initiator was varied from 0.25 to 3.00 weight% with respect to the butyl methacrylate (BMA) monomer. All polymerization reactions were conducted at 75$^{\circ}C$. It is found that stabilizer concentration has no impact on reaction kinetics, while an increase in initiator concentration enhances polymerization reaction rate. Increase of carbon black concentration from 1 to 3 to 5 wt% into PBMA displayed progressive decrease in reaction conversion. The particle diameter of PBMA composite particles containing carbon black was found to be between 5 and 30 ${\mu}m$. Glass transition was determined to range from 23.8 to 24.7$^{\circ}C$, irrespective of variation in the concentration of stabilizer, initiator or carbon black.

• Journal of Environmental Science International
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• v.21 no.5
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• pp.597-603
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• 2012

Non-thermal plasma processing using a dielectric barrier discharge (DBD) has been investigated as an alternative method for the degradation of non-biodegradable organic compounds in wastewater. The active species such as OH radical, produced by the electrical discharge may play an important role in degrading organic compound in water. The degradation of N, N-Dimethyl-4-nitrosoaniline (RNO) was investigated as an indicator of the generation of OH radical. The DBD plasma reactor of this study consisted of a plasma reactor, recycling pump, power supply and reservoir. The effect of diameter of external reactor (15 ~ 40 mm), width of ground electrode (2.5 ~ 30 cm), shape (pipe, spring) and material (copper, stainless steel and titanium) of ground electrode, water circulation rate (3.1 ~ 54.8 cm/s), air flow rate (0.5 ~ 3.0 L/min) and ratio of packing material (0 ~ 100 %) were evaluated. The experimental results showed that shape and materials of ground were not influenced the RNO degradation. Optimum diameter of external reactor, water circulation rate and air flow rate for RNO degradation were 30 mm, 25.4 cm/s and 4 L/min, respectively. Ground electrode length to get the maximum RNO degradation was 30 cm, which was same as reactor length. Filling up of glass beads decreased the RNO degradation. Among the experimented parameters, air flow rate was most important parameters which are influenced the decomposition of RNO.

• Journal of the Korean Society of Costume
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• v.66 no.7
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• pp.171-191
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• 2016

Lady Han, Gongshin-buin(恭愼夫人韓氏: 1410~1483) was Gongnyeo of Ming emperor and sister of Han Hwak(韓確:1400~1456). The aim of this study is to analyze the characteristic of costume presents for Lady Han, and to investigate a part of Joseon women's attire in the 15th century. Most of the presents for Lady Han were native products of Joseon to help alleviate her homsickness, but surviving relics are very rare. The costume-related presents included daily accessories and fabrics such as natural ornaments, embroidered pouch, needle case, wig, wooden comb, portable knife with multi-blades, various colored plain silk [綿紬] and ramie. Also, preceding research analysis of costume relic were combined with study of presents for Lady Han's. The most salient costume of Joseon women in the 15th century was the symmetric collared jacket. In addition, ornamented jeogori, pouch with pine nut stitch, chima, jangot, jangsam, black veil[羅兀] made with ra or jeung, glass beads, paintings of Ming and Joseon can be references. Illustrations show 6 representative type of Joseon women's full attires in the 15th century are as follows. First, is a combination of 'symmetric collared jacket with peacock rank badge, jeoksam, chima, underwear' and 'hoa-a, janga-a, embroidered pouch, needle case, knife with multi-blades: presents for Lady Han'. Second, formal wear focusing on symmetric collared Jacket of cloud pattern. Third, formal wear focusing on multicolor ornamented jeogori. Fourth, town wear with jangot and neoul. Fifth, formal wear with jangsam. Sixth, daily wear focusing on banbi with symmetric squre collar. Accessories and underwear shown in another illustration were same as the first illustration. Results of this study can be used as content for making historically accutate costumes as well as costume education.

• The Journal of Internal Korean Medicine
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• v.27 no.2
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• pp.471-479
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• 2006

Backgrounds & Objectives: Banhasasimtang granule(BHSST) has been used for the treatment of functional dyspepsia regarded as one of the gastric dysmotility disease. but its mechanisms of action are not well known yet: So we investigated the effects of BHSST on gastric emptying and its mechanisms of action in rats. Methods: Gastric emptying was measured by glass beads(1mm in diameter) expelled from the stomach for 60 min after administration of normal saline(NS) or BHSST 31mg/kg or 93mg/kg in rats. And by the same method gastric emptying was measured after administration of NS or BHSST 93mg/kg in rats treated with atropine sulfate(1mg/kg, s.c.), quinpirol HCI(0.3mg/kg, i.p.), NAME(NG-nitro-L-arginine methyl ester, 75mg/kg, s.c.) or cisplatin(10mg/kg, i.p.) to make delayed gastric emptying. Results: BHSST 93mg/kg improved gastric emptying more than NS or BHSST 31mg/kg(p=0.016). Under the delayed gastric emptying, BHSST 93mg/kg improved gastric emptying in the group treated with NAME$(5.00{\pm}3.101\;vs\;9.00{\pm}3.51,\;p\;=0.046)$, but aggravated it With atropine sulfate$(5.71{\pm}3.45\;vs\;2.57{\pm}1.62,\;p\;=0.050)$ and cisplatin$(12.7{\pm}2.29\;vs\;8.57{\pm}5.06,\;p\;=0.072)$. Conclusions: BHSST improves the gastric emptying through cholinergic and 5-hydroxytryptamine 3 receptors. Especially it is effective to improve gastric emptying delayed by NAME. So we expect that it would be effective in functional dyspepsia with impaired reservoir functions such as gastric adaptive relaxation.

• The Journal of Internal Korean Medicine
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• v.28 no.2
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• pp.242-249
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• 2007

Backgrounds & Objectives : Yukgunjatanggranule (YGJT) ha been used for the treatment of functional dyspepsia, regarded as one of the gastric dysmotility diseases, but its mechanisms of cation are not yet well known, We investigated the effects of YGJT on gastric emptying and its mechanisms of action in rats. Methods : Gastric emptying was measured by glass beads (1mm in diameter) expelled from the stomach for 1 hour and 2 hours after administration ofnormal saline (NS) or YGJT 41.6mg/kg or 124.8mg/kg in rats. By the same method, gastric emptying was measured only for 2 hours after administration of NS of YGJT 124.8mg/kg in rats treated with atropine sulfate (1mg/kg, s.c), quinpirole HCl(0.3mg/kg, i.p.), NAME (NG-nitro-L-arginine methyl ester, 75mg/kg, s.c.) or cisplatin (10mg/kg, i.p.) to delay gastric emptying. Results : YGJT 124.8mg/kg improved gastric emptying more than NS or YGJT 41.6mg/kg (p=0.046). Under delayed gastric emptying, YGJT 124.8mg/kg improved gastric emptying in the group treated with cisplatin ($3.1{\pm}1.3$ vs. $6.6{\pm}3.1$, p=0.015), quinpirole HCl ($4.7{\pm}2.8$ vs. $5.5{\pm}5.6$, p=0.874) and NAME ($2.2{\pm}1.4$ vs. $4.7{\pm}6.0$, p=0.414), but aggravated it with atropine sulfate ($1.8{\pm}0.9$vs. $1.7{\pm}1.0$, p=0.957). Conclusions : YGJT improves gastric emptying through the cholinergic pathwas, and shows some effect against the toxicity of cisplatin. Therefore, we expect that it would be effective in relieving gastrointestinal symptoms in functional dyspepsia patients and cisplatin-treated patients.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.625-630
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• 2004

Granular media filtration is used almost universally as the last particle removal process in conventional water treatment plants. Therefore, superb particle removal efficiency is needed during this process to ensure a high quality of drinking water. However, every particle can not be removed during granular media filtration. Besides the pattern of particle attachment is different depending on physicochemical aspects of particles and suspension. Filtration experiments were performed in a laboratory-scale filter using spherical glass beads with a diameter of 0.55 mm as collectors. A single type of particle suspension (Min-U-Sil 5) and alum coagulation was used to destabilize particles. The operating conditions were similar to those of standard media filtration practice: a filtration velocity of 5 m/h. More favorable particles, i.e., particles with smaller surface charge, were well attached to the collectors especially during the early stage of filtration when zeta potential of particles and collectors are both negative. This selective attachment of the lower charged particles caused the zeta potential distribution (ZPD) of the effluent to move to a more negative range. On the other hand, the ZPDs of the effluent moved from more positive to less positive when the surface charge of particles was positive and this result was thought to be caused by ion transfer between particles and collectors.

• Journal of the Korean Chemical Society
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• v.28 no.5
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• pp.293-301
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• 1984

-ray fluorescence analysis of $Ta_2O_5$, $Nb_2O_5$ and $ZrO_2$ in tin-slag samples using the simple dilution method was studied. The method is to correct mathematically the calibration curve to the linear line by the dilution. One synthesized standard having similar composition to the sample and tin slag samples were diluted with anhydrous $Li_2B_4O_7$ at the level of 1%, 2% and 3% of the sample content respectively. The diluted samples were fused at $1150^{\circ}C$ for 30 minutes and these glass beads were finely ground and pelletized. Measuring the X-ray intensities with these pellets, analytical results were calculated by the equation derived from J. Scherman's equation for the characteristic X-ray intensity of an element. Analytical results agreed with the reference values obtained by the standard calibration method within allowable error range and were reproducible.

• Journal of the Korean Chemical Society
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• v.28 no.5
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• pp.302-308
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• 1984

X-ray spectrometric determination of $Ta_2O_54, $Nb_2O_5$ and $ZrO_2$ in tin-slag samples using the double dilution technique was conducted. Tin-slag samples and one synthesized standard sample having similar composition to the samples were diluted with anhydrous $Li_2B_4O_7$ at the level of 1.00, 2.00 and 3.00% of the sample content, respectively. The diluted samples were fused at $1,150^{\circ}C$ for 30 minutes, and these glass beads were finely ground and pelletized. With the X-ray intensities measured, analytical results were calculated by the double dilution equation. The results agreed to the reference values obtained by the standard calibration method and the simple dilution technique within allowable error range and were reproducible.

• Resources Recycling
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• v.22 no.3
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• pp.65-72
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• 2013

A vertical column pneumatic separator was modified to improve its separation performance. A branch column was installed at the center of the main column, which created a bypass flow and changed the flow rate of the main column before and after the branch column. To separate a mixture comprising light and heavy materials, the airflow in main column after the branch column was set to lift the only light materials and the airflow in main column before the branch column was set to prevent the flow of the light materials from flowing downwards. Materials directed into the branch column were separated from the flow and returned to the feeder through the cyclone linked to the branch column. The performances of the straight-type separator and the modified separator were compared using glass and zirconia beads with a narrow size distribution.

• Journal of the Korean Geotechnical Society
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• v.38 no.11
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• pp.7-17
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• 2022

This study investigates the effect of cylindrical baffle arrays behind a rigid barrier on debris flow behavior and dynamic impact load. Small-scale tests were performed with various transverse blockage ratios and row numbers of baffles. High-speed cameras were installed at the flume's top and side, and load cells were installed in front of the rigid barrier. Moreover, glass beads simulated large boulders with debris flow in the flume. Test results revealed that the impact load of debris flow on the rigid barrier was significantly reduced using the cylindrical baffles behind the rigid barrier. In addition, the increased transverse blockage ratio of baffle arrays led to a greater impact load of debris flow because of flow suppression due to the baffle arrays.