• Journal of the Korea Institute of Building Construction
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• v.17 no.4
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• pp.305-312
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• 2017

To evaluate the reliability of fly ash quality supplied to ready-mixed concrete plant using mass cylinder and hydrometer, in this research, the correlationship between the fly ash properties provided from certification and density measurement with suspension was evaluated. As a result, the reliability of the certification, except fineness and loss on ignition, all properties had a discord. Additionally, in the case of density, fineness, and L.O.I, the relation with the density measured using hydrometer showed high correlation, especially fineness was strongly related with the density measured using hydrometer. Furthermore, according to the comparative analysis with previous research, the fly ash used in this research was similar measurement with raw powder without any refining process, it is considered that the constant error of blaine test or using raw ash sample as a fly ash. In current standard regarding fly ash, the fineness range of class 2 can be changed from $3,000-4,500cm^2/g$ to $3,500-4,500cm^2/g$ for improved quality of fly ash in fineness aspect.

• Journal of the Mineralogical Society of Korea
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• v.21 no.2
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• pp.177-182
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• 2008

The Gemological characteristics of B.C. jade from Cassiar Mine, British Colombia, Canada, have been investigated, using polarizing microscopy, Mohs' hardness, refractive index and density measurements, X-ray powder diffraction, X-ray fluorescence spectrometry, ICP-MS, Infrared absorption spectrometry, and DTA/TGA. The B.C. jade is deeply green (spinach peen or olive green) in color and is translucent. It shows a resinous or waxy luster. The principal mineral of the material is tremolite-actinolite solid solution and minor amount of Cr-garnet and unidentified opaque minerals are accompanied. Mohs' hardness value ($5.5{\sim}6$). refractive index (1.62), and specific gravity (3.01) are measured. It is very highly tough and shows hackly fracture. The high Fe content ($Fe_2O_3\;4.14{\sim}4.66\;wt%$) in B.C. jade is attributable to a deepening of green color of the material. The B.C. jade starts to dehydrate at v and dehydration is completed at $1000.8^{\circ}C$, transforming tremolite-actinolite solid solution to enstatite, diopside, quartz, and water in its place. This possible reaction is supported by the weight loss of B.C. jade (1.93 wt%) at $1000.8^{\circ}C$ indicated by TGA curve.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.1
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• pp.8-14
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• 1996

Use of phosphate coated urea to decrease ammonia volatilization from directly seeded paddy under dryland condition at early stage was tested. Effect on urea hydrolysis was investigated through laboratory study comparing with use of thiourea, a urease inhibitor, under different water content. A field measurement of volitilized ammonia with phosphate-glycerol ammonia absorber was conducted for surface treated urea, phosphate coated urea, phosphate coated slow-release fertilizer and organic fertilizer. Through laboratory study, hydrolysis rate of phosphate coated urea at three days after treatment was lower than that of urea, however, the rate after one week was same. Thiourea addition retarted urea hydrolysis. By field measurement, ammonia volatilization was effectively reduced by use of phosphate coated urea.

• Journal of Animal Environmental Science
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• v.15 no.3
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• pp.241-250
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• 2009

This study was conducted to develop an prototype automatic feeder (AF) for growing-finishing pigs. The main components of AF were a feed storage hopper, a feeding motor, a feed agitator, a control box and a programmable IC, which were controlled by a personal computer. The powder type feed transfer rate of AF was average $9.83{\pm}0.4\;g\;s^{-1}$. In feeding test, growing pigs (Landrace) of about 43 kg live weight were used in the study, and was fed over a 6 weeks in pens with solid concrete floors. For feeding trials with AF, the operation time of the feeding motor was set to 2, 3, 4, 5, and 6 seconds per feeding. Pigs frequently used AF from 05:00 to 11:00 and from 11:00 to 17:00 without relationship to the operation time of the feeding motor. The AF operation time of the feeding motor to minimize feed loss was between 2 and 4 seconds. Pigs fed with AF had same or slightly higher average daily gam (0.8~0.9 kg) than that with a commercial feeder, and average daily feed intake (2.76~2.93 kg) and feed conversion ratio (3.10~3.66) of pigs fed with AF were same or lower than those with the commercial feeder except the operation time of the feeding motor set to 6 seconds. As a result, AF would help to use and improve the productivity of growing-finishing pigs.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.51-51
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• 2010

Recently just as in the automobile industry, shipbuilders also try to reduce material consumption and weight in order to keep operating costs as low as possible and improve the speed of production. Naturally industry is ever searching for welding techniques offering higher power, higher productivity and a better quality. Therefore it is important to have a details research based on the various welding process applied to steel and other materials, and to have the ability both to counsel interested companies and to evaluate the feasibility of implementation of this process. Submerged-arc welding (SAW) process is usually used about 20% of shipbuilding. Similar to gas metal arc welding(GMAW), SAW involves formation of an arc between a continuously-fed bare wire electrode and the work-piece. The process uses a flux to generate protective gases and slag, and to add alloying elements to the weld pool and a shielding gas is not required. Prior to welding, a thin layer of flux powder is placed on the work-piece surface. The arc moves along the joint line and as it does so, excess flux is recycled via a hopper. Remaining fused slag layers can be easily removed after welding. As the arc is completely covered by the flux layer, heat loss is extremely low. This produces a thermal efficiency as high as 60% (compared with 25% for manual metal arc). SAW process offers many advantages compared to conventional CO2 welding process. The main advantages of SAW are higher welding speed, facility of workers, less deformation and better than bead shape & strength of welded joint because there is no visible arc light, welding is spatter-free, fully-mechanized or automatic process, high travel speed, and depth of penetration and chemical composition of the deposited weld metal. However it is difficult to application of thin plate according to high heat input. So this paper has been focused on application of the field according to SAW process for thin plate in ship-structures. For this purpose, It has been decided to optimized welding condition by experiments, relationship between welding parameters and bead shapes, mechanical test such as tensile and bending. Also finite element(FE) based numerical comparison of thermal history and welding residual stress in A-grade 3.2 thickness steel of SAW been made in this study. From the result of this study, It makes substantial saving of time and manufacturing cost and raises the quality of product.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.702-708
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• 2018

Volatile organic compounds (VOCs), as a significant air pollutant, is generated mainly from the burning of fossil fuels, building materials using painting, etc. The inhalation of a certain amount of VOCs can be deleterious to human health, e.g., headaches, nausea and vomiting. In addition, it can also cause memory loss and even increase the rate of leukemia. Therefore, as one of the methods for reducing VOCs in air, polyacrylonitrile/fly ash (PAN/FA) composite nanofibrous membranes were fabricated by electrospinning. To observe their VOCs adsorption capacity, the morphological structure of PAN/FA nanofibrous mats was investigated by field emission scanning electron microscopy (FE-SEM), and the VOCs (chloroform, benzene, toluene, and xylene) adsorption capacity of PAN/FA membranes were tested by gas chromatography/mass spectrometry (GC/MS). The results indicated that the PAN nanofiber containing 40 wt. % FA powder had the smallest fiber diameter of 283 nm; they also showed the highest VOCs adsorption capacity compared to other composite membranes.

• Korean Journal of Food Science and Technology
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• v.42 no.1
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• pp.97-102
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• 2010

Curcuminoids are polyphenolic compounds and include curcumin and its derivatives possessing a yellow color. In the present study, changes in the chemical stability and antioxidant activities of curcuminoids, including curcumin, demethoxycurcumin (DMC), and bisdemethoxycurcumin (BMC), were investigated under various processing conditions. The yellowness of a mixture of the curcuminoids (79.4% curcumin, 16.8% DMC, and 3.8% BMC) at 405 nm was proportional to their amounts analyzed by HPLC. The curcuminoids became less stable with increases of pH and temperature during storage. Exposing a solution of the curcuminoids to autoclave conditions ($121^{\circ}C$, 1.2 atm for 15 min) decreased residual curcuminoid levels by 80-90%; however, as a powder under the same conditions the curcuminoids were much more stable with less than 10% loss. After autoclave treatment, scavenging activities of the curcuminoids for DPPH and ABTS radicals were reduced by 10.3 and 33.4%, respectively, whereas nitric oxide scavenging activity was slightly increased. The residual levels of curcumin, DMC, and BMC after autoclaving were 0.7, 1.4, and 0.9%, respectively, indicating that curcumin was the most sensitive to autoclave treatment. The results indicate that under processing conditions, pH and temperature markedly affect the stability of curcuminoids and major losses of curcuminoids occur after autoclaving. These conditions should be considered when processing foods containing curcuminoids.

• The Journal of the Petrological Society of Korea
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• v.25 no.2
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• pp.107-119
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• 2016

Trace element abundances in the igneous rocks are important data for petrogenetic interpretation. Their concentrations are generally measured using ICP-MS from the dissolved solution. The acid digestion of rock powder can be performed by conventional teflon vial or pressure bomb. In this paper, we investigated a problem that happened during acid digestion experiment using conventional teflon vial or pressure bomb of BCR2 and GSP2 USGS rock standard materials. The results show that the measured concentrations of the elements like Cr, Ni, Zn, Ta, W in the BCR2 are different from the recommended values of USGS whereas those of the elements like Rb, Sr, Zr, Hf, Ta, W in the GSP2 are different from those values. Our experiment shows that defect of specific elements like Cr, Ni may happen during the sample digestion. Our results also indicate that the Cr, Ni, W, Zr, Hf, Ta concentration obtained based on an acid digestion of geological samples need to be careful in their geochemical interpretation.

• The Journal of Korean Medicine
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• v.19 no.1
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• pp.179-204
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• 1998

The purpose of this research was to investigate the efficacy of Goiwhasan extract powder on the gastric injuries, antiulcer, gastrointestinal tract and blood hemostasis. Animals were used through this studies mice and rats. All animals were divided into 3 groups, contol group(no treatment), sample Ⅰ group(375mg/kg administration), sample Ⅱ group(750mg/kg administration). The gastric injuries and ulcer have been made by using pyloric ligation, indomethacin, HCI-ethanol, acetic acid and then The histological observation was followed. In the gastrointestinal tract, gastric juice secretion, gastric acidity, pepsin output, blood gastrin and secretin level, transport potentials in the small and large intestine were checked. And studies on blood hemostasis were performed on normal hemostatic activities and plasma prothrombin time, plasma recalcification time, plasma fibrinogen levels in the hypoprothrombinemic mice induced by warfarin. The results were as follows: 1. The antigastric ulcer effects on the pyloric ligation, indomethacin, HCl-ethanol, acetic acid induced gastric injuries were shown in Sample Ⅱ group(p<0.05). 2. Through the morphologic examination on the acetic acid induced ulcer, Sample Ⅰ group showed mild regeneration of epithelium and slight decrease of periulcer edema then that of Control group, while Sample Ⅱ group showed more retraction of round ulcer site, remarkable loss of swelling and edema then that of Control group, and revealing the regenerated epithelium in the surrounding ulcer site. Thus it was noted that both Sample groups have antigastriculcer effects on the experimentally induced gastric ulcer. 3. The inhibitory effects on gastric juice were noted in both Sample Ⅰ group(p<0.05) and Sample Ⅱ group(p<0.01). However, only Sample Ⅱ group showed the inhibitory effects on total acidity and pepsin output(p<0.05). 4. The significant inhibition of blood gastrin level showed at 30 min.(P<0.05) and 90 min.(P<0.05) after starting medication in only Sample Ⅱ group, but significance of blood secretin level in both groups was not recognized. 5. Any significant changes in barium sulfate transport in the small intestine of mice was not recognized in both groups, but the significantly inhibitory effect in large intestine was recognized in both Sample Ⅰ group(p<0.05) and Sample Ⅱ group(p<0.001). 6. In hemostatic effect on both normal mice and hypoprothrombinemic mice induced by warfarin, the significantly shortening effect on coagulation time was seen in only Sample Ⅱ group(p<0.01). 7. On plasma prothrombin time in hypoprothrombinemic rat induced by warfarin, Sample Ⅱ group have shortened the prothrombin time significantly(p<0.001). 8. On plasma reclcification time in hypoprothrombinemic rat induced by warfarin, the recalcification time have been shortened significantly in both Sample Ⅰ group(p<0.05) and Sample Ⅱ group(p<0.01). 9. On plasma fibrinogen levels in hypoprothrombinemic rat induced by warfarin, the fibrinogen contents in Sample Ⅱ have been decreased significantly(p<0.01). Overall the above results suggest that Goiwhasan has an therapeutic efficacy on antigastric ulcer and blood hemostasis. Further studies would be needed on the interaction of its herbal medicine and its mechanism in the future.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1604-1612
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• 1999

The study was carried out to investigate the quality of the wet noodle added with the powders of nopal and nopalitos from Opuntia ficus-indica. The wet noodles were prepared to the ratio of 3, 6 and 9% (w/w) of the nopal and the nopalitos based on a flour weight. The initial pasting temperature and final viscosity in an amylograph decreased as the increase of the nopal and the nopalitos powders. A cooked weight and volume decreased with the increase of the nopal and the nopalitos powders, while a cooking loss increased. From the sensory evaluation, the wet noodles included 3% nopalitos and 6% nopal powders were similarly evaluated as the noodle used whole wheat flour. Bacterial counts of wet noodle with the nopal and the nopalitos powders were always lower than those of the control. Bacterial counts of wet noodle slowly increased as the increase of the amount of nopal and the nopalitos powders during storage at $4^{\circ}C\;and\;20^{\circ}C$. The methanol extracts from the nopal showed antimicrobial activities against Escherichia coli, Escherichia coli O157 : H7, Salmonella typhimurium, and Bacillus subtilis, while the extracts from the nopalitos showed antimicrobial activity only against Escherichia coli.