• Journal of Powder Materials
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• v.1 no.1
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• pp.72-78
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• 1994

Two kinds of $U_3Si$ powders and $U_3Si$ dispersed nuclear fuel meats have been prepared by conventional comminution process and a newly developed rotating disk atomization process. In contrast to angular shape and broad size distribution of the conventionally processed powder, the atomized powder was spherical and showed narrow size distribution. For the atomized powder, the heat treatment time for the formation of $U_3Si$ by a peritectoid reaction was reduced to about one tenth, thanks to microstructure refinement by rapid cooling of about 5$\times$104 K/s. The extruding pressure of atomized $U_3Si$ powder and Al powder mixture was lower than that of comminuted $U_3Si$ and Al powder mixture. The elongation of the atomization processed fuel meats was much higher than that of the comminution processed fuel meats and remained over 10% up to 80wt.% of $U_3Si$ powder fraction in the fuel meats. It appears therefore that the loading density of $U_3Si$ in fuel meat can be increased by using atomized $U_3Si$ powder. The atomized spherical particles were randomly distributed, while the comminuted particles with angular and longish shape were considerably aligned along the extrusion direction. Along the transverse direction of the extraction the electrical conductivity of the atomization processed fuel meats was appreciably higher than that of comminution processed fuel meats. This tendency became pronounced as $U_3Si$ content increased. Because the thermal conduction which is believed to be proportioned to the electrical conduction in the nuclear fuel meats occurs in radial direction, the atomization processed fuel can be better used in research reactors where high thermal conductivity is required.

• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.843-850
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• 2012

Due to the fast response to algae bloom issue in drinking water treatment plant, very fast determination methodology for algal toxin is required. In this study, column switching technique based online preconcentration method was combined with high resolution full scan mass spectrometer to save sample preparation time and to obtain fast and accurate result. After parameter optimization of online preconcentration, 1mL filtered sample was directly injected to trap column with switching valve system. Next, target toxins are eluted by 98% acetonitrile and analysed with 150 - 1,100 amu scan range at 50,000 resolving power. Method detection limit (MDL) for microcystin-LR, the most toxic isomer, was 0.1 ng/mL and others such as microcystin-YR, microcystin-RR and nodularin were 0.08, 0.03 and 0.04 ng/mL, respectively. This is the best improved sensitivities with 1mL volume in the literature. Furthermore, due to the use of ultra pressure HPLC (UPLC), the whole method run was completed in 4 min. Real sample applications for 173 sample including 55 surface water and 118 treatment plant samples for raw and treated water could be done within 16 hours. In our calculation, this methodology is roughly 80% faster than the previous manual solid-phase extraction with LC-MS/MS method.

• The korean journal of orthodontics
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• v.49 no.6
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• pp.413-426
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• 2019

This study was performed to describe the longitudinal management of recurrent temporomandibular joint (TMJ) ankylosis from infancy to adulthood in perspective of surgical and orthodontic treatment. A 2-year-old girl was referred with chief complaints of restricted mouth opening and micrognathia due to bilateral TMJ ankylosis. For stage I treatment during early childhood (6 years old), high condylectomy and interpositional arthroplasty were performed. However, TMJ ankylosis recurred and symptoms of obstructive sleep apnea (OSA) developed. For stage II treatment during early adolescence (12 years old), gap arthroplasty, coronoidectomy, bilateral mandibular distraction osteogenesis, and orthodontic treatment with extraction of the four first premolars were performed. However, TMJ ankylosis recurred. Because the OSA symptoms reappeared, she began to use a continuous positive airway pressure device. For stage III treatment after completion of growth (20 years old), low condylectomy, coronoidectomy, reconstruction of the bilateral TMJs with artificial prostheses along with counterclockwise rotational advancement of the mandible, genioglossus advancement, and orthodontic treatment were performed. After stage III treatment, the amount of mouth opening exhibited a significant increase. Mandibular advancement and ramus lengthening resulted in significant improvement in the facial profile, Class I relationships, and normal overbite/overjet. The OSA symptoms were also relieved. These outcomes were stable at the one-year follow-up visit. Since the treatment modalities for TMJ ankylosis differ according to the duration of ankylosis, patient age, and degree of deformity, the treatment flowchart suggested in this report could be used as an effective guideline for determining the appropriate timing and methods for the treatment of TMJ ankylosis.

• The Journal of Internal Korean Medicine
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• v.39 no.6
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• pp.1150-1167
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• 2018

Objective: The purpose of this study was to investigate the effect reducing blood pressure (BP) using Xuefuzhuyu Decoction (XFZYD) in adults with essential hypertension (EH). Method: Search engine, such as PubMed, EMBASE, Cochrane library, Web of Science, J-STAGE, CiNii, CNKI, OASIS, NDSL, KISS, RISS, and DBpia, were used. The search period was from the beginning of the search engine to June 30, 2018 and there were no limits regarding languages. The selection and extraction of literatures were performed independently by two authors. Meta-analysis was done on the total effective rate (TER), Systolic BP (SBP) and Diastolic BP (DBP). Cochrane's risk of bias (ROB) was used as the methodological quality assessment scale. Results: Twenty studies were finally selected. We observed that a combination treatment using XFZYD and an antihypertensive drug (AHD) was 5.1 times more effective in lowering BP than using AHD alone on TER. The mean differences in SBP and DBP were -10.65 mmHg (95% Confidential Interval (CI) -13.55 mmHg, -7.74 mmHg, P<0.00001), -5.92 mmHg (95% CI -7.14, -4.38, P<0.00001), respectively. Conclusion: A combination treatment using XFZYD and AHD may be more effective in reducing BP than using AHD alone. Because of the poor methodological quality of the studies conducted thus far, high-quality clinical trials will be required in the future.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.5
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• pp.98-104
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• 2022

When processing parts, the cutting oil can improve the cooling performance of the workpiece and tool to increase the precision of the workpiece or extend the life of the tool and facilitate chip extraction. Since such cutting oil has a harmful effect on the environment and the human body due to additives such as sulfur, research on a minimum lubrication supply method using an eco-friendly oil is recently underway. The minimum lubrication supply method minimizes the amount of cutting oil used during processing and processes it, which can reduce the amount of cutting oil used, but has a problem in that cooling performance efficiency is poor. Therefore, this study conducted a study on mist cooling of lubricants to reduce the amount of cutting oil used and maximize the cooling effect of processing heat generated during tapping processing. Spray pressure, processing speed, direction, and lubricant spray amount, which are considered to have an effect on cooling performance, were set as process conditions, and the effect on temperature was analyzed by performing an experiment using the box benquin method among experiments were analyzed. Through the experimental analysis results, the optimal conditions for mist and processing that maximize the cooling effect were derived, and the validity of the results derived through additional experiments was verified. In the case of processing by applying the mist lubrication method verified through this study, it is considered that high-precision processing is possible by improving the cooling effect.

• Culinary science and hospitality research
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• v.18 no.2
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• pp.149-161
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• 2012

The purpose of this study is to examine the quality characteristics of lamb stock by different salt contents in it. For this purpose, mechanical tests (color value, pH, sugar content, salinity, amino-acid content) and sensory evaluation (attribute difference test & acceptance) were conducted, showing the following results; Salinity and sugar increased significantly (p<0.01, p<0.001) with salt contents increased. The 0.1% salt addition group contained 32 kinds of free amino-acids, while 0.2% and 0.3% contained 34. 0.4% salt addition group turned out to contain 34 kinds of free amino-acid in it. The amount of the free amino-acid content was also the highest with 0.3% sample group, followed by 0.2%, 0.4%, and 0.1% sample group. In the test group, 9 kinds of essential amino-acid were discovered, and all samples contained histidine and arginine, which were essential in the growth of children. Among all samples, arginine appeared to be the highest in content. Each of the essential amino-acid content varied with statistical significance among the sample groups. In addition, 14 kinds of amino-acids other than the above mentioned were discovered, as well. The 0.3% salt addition group showed the highest 'after taste' value, and the differences among the sample groups were statistically significant(p<0.001). The acceptance test of the lamb stock showed that the flavor and mouth feel did not vary among the sample groups with statistical significance. The control group had the highest value for appearance, measuring scoring 4.32, and the sample group of 0.2% salt addition showed the lowest value of appearance, scoring 3.63. As for the preference on the taste, the highest value of 4.09 came from the 0.3% salt addition group. The differences between the sample groups were statistically significant. Finally, with regard to the overall quality, the 0.3% salt addition group had the highest value of 4.23 while the control group scored the lowest, 3.52. The differences among the samples were statistically significant. The overall result of the study indicated that the optimal rate of salt addition in making lamb stock was 0.3%.

• Clean Technology
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• v.9 no.4
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• pp.197-206
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• 2003

We performed removal of aromatic compounds, benzene and toluene, from soil and zeolite using supercritical carbon dioxide. Extraction was performed at $50^{\circ}C$ and 27.7 MPa with changing the extent of pollutant concentration and the results were compared and analyzed. Experiments were carried out using flow method and high pressure extractor of 1.27 cm in diameter and 25cm in length was used. The pollutants were sampled every ten minutes and their concentrations were analyzed with GC/FID. As a result, highly contaminated sample followed solubility/elution model and slightly contaminated sample followed desorption/kinetics model. At the same condition benzene was extracted faster than toluene. In the case of zeolite, more time is required to extract pollutants than soil. This phenomena was due to high adsorption capacity of zeolite. In the case of highly contaminated soil, we could correlate experimental data using simple Brady's fixed bed extractor model. But in the case of slightly contaminated soil, that was governed with desorption/kinetics model, there was some errors.

• Korean Journal of Food Science and Technology
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• v.14 no.3
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• pp.244-249
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• 1982

In order to reduce malic acid in low-alcohol content appel wine $(6{\sim}9%)$ malate-decomposing yeast, Schzosaccharomyces japonicus var. japonicus St-3 was used. Fallen apples before the harvesting season were collected and extraction was made. The apple extract was fortified with sucrose to make final sugar concentration of 18% in case of 9% base wine. High acid content in the primarily fermented apple wine could be reduced by following with malo-alcoholic fermentation using Schizosaccharomyces japonicus var. japonicus St-3 in second half of alcoholic fermentation using Saccharomyces sp. R-11. Secondary fermentation was proceeded at low temperature $(7{\sim}8^{\circ}C)$ for 130 days using Saccharomyces sp. R-11. Prior to the secondary fermentation, two percent of sugar was added to the base wine in order to produce carbon dioxide gas. And each five percent of specially prepared malt extract and hop extract were added to the base wine in order to increase foam stability. Better shelf-life was observed by keeping high carbon dioxide pressure$(2.3{\sim}2.5kg/cm^2)$ in the bottle. It was assured that the better low-alcohol content apple wine could be brewed by the method which we used above.

• The Journal of Engineering Geology
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• v.27 no.3
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• pp.233-244
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• 2017

We conducted hydraulic fracturing experiments on cement samples to investigate the dependency of fracture propagation on the viscosity of injection fluid and the in situ stress state. Ten cubic samples (20 cm side length) were produced using cement that was cured in water for more than one month. Samples were placed in a tri-axial compression apparatus with three independent principal stresses. An injection hole was drilled and the sample was hydraulically fractured under a constant injection rate. We measured injection pressures and acoustic emissions (AE) during the experiments, and investigated the fracture patterns produced by hydraulic fracturing. Breakdown pressures increased exponentially with increasing viscosity of the injection fluid. Fracture patterns were dependent on differential stress (i.e., the difference between the major and minor principal stresses). At low differential stress, multiple fractures oriented sub-parallel to the major principal stress axis propagated from the injection hole, and in some samples the fracture orientation changed during propagation. However, at high differential stress, a single fracture propagated parallel to the major principal stress axis. AE results show similar patterns. At low differential stress, AE source locations were more widespread than at high differential stress, consistent with the fracture pattern results. Our study suggests that hydraulic fracturing during shale gas extraction should be performed parallel to the orientation of minimum differential stress.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.443-447
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• 2016

The microalgae have cellulose as a main structural component of their cell wall and the lignin content in microalgae is much lower than other lignocellulosic biomass. Therefore, fermentable sugar production from microalgae (Tetraselmis KCTC 12236BP) can be carried out under pretreatment without high temperature and high pressure. It was investigated that the effect of hot-water pretreatment using sulfuric acid for lipid extracted algae which is expected to be a next generation biomass. The effects of three major variables including extraction temperature, acid concentration and time on the enzymatic hydrolysis were investigated. Among the tested variables, temperature and acid concentration showed significant effects and optimum pretreatment conditions for the economic operation criteria were obtained as follows: reaction temperature of $120^{\circ}C$, sulfuric acid concentration of 2 mol and pretreatment time of 40 min. Under the optimum conditions of acidic hot water pretreatment, experimentally obtained hydrolysis yield were 95.9% which showed about 2.1 fold higher compared with enzymatic hydrolysis process. Therefore, acid pretreatment under mild condition was proven to be an effective method for fermentable sugar production from lipid extracted microalgae.