• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.416-424
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• 1996

Reinforced Concrete structures need repair and rehabilitation due to the deterioration such as crack, spalling and disintegration. Numerous repair materials which are currently used in cinstruction fields witdout any specifications are examined in terms of their serviceabilities and effectiveness. In this paper sections of R/C beams are enlarged with repari material(epoxy, latex, premix), and then they are strengthened with rebar, steel plate of CFRP sheet on the tension side. Structural behaivior of strengthened beams are investigated under stactic tests and compared with each parameters.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.63-64
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• 2021

In this study, Coal gasification slag(CGS) was replaced with fine aggregate to verify the physical properties of the concrete according to the change in cement types. As a result of the study, the use of CGS resulted in a decrease of superplasticizer and an decrease of AE agent. In addition, when 50% of mixed cement and CGS were replaced, the initial strength expression was delayed, and the strength enhancing effect was judged to be weak.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.4
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• pp.391-394
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• 1999

A feeding experiment was conducted using juvenile abalone (Haliotis discus hannai) to investigate the optimum level of supplemental vitamin and/or mineral premixes in a formulated diet for practical feed formulation. Three replicate groups of abalone averaging 100 mg were fed the diets containing different levels of vitamin premix ($0\%,\;0.5\%,\;1.0\%$ and $2\%$) and /or mineral premix($0\%,\;2\%,\;4\%$ and $6\%$) for 4 months. Survival rates of abalone showed no distinctive trend by the levels of dietary vitamin premixes. Weight gain, shell growth and soft body weight of abalone were not significantly affected by the different dietary vitamin and/or mineral premixes (P>0,05). Moisture, protein and lipid contents of soft body were influenced by experimental diets (P<0.05) but these differences also had no definite trends by levels of vitamin and/or mineral premixes. These data indicate that supplemental vitamin or mineral premix is not needed in this formulated diet, therefore price of diet for juvenile abalone could be reduced.

• 한국도로학회:학술대회논문집
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• 2010.09a
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• pp.137-140
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• 2010

• Journal of Powder Materials
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• v.14 no.3 s.62
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• pp.202-207
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• 2007

Novel polymer mold process for fabrication of microcomponents using metal nanopowders was developed and experimentally optimized. Polymer mold for forming green components was produced by using a hard master mold and polydimethylsiloxane (PDMS). In the preparation of metallic powder premix for the green components without any defect, 90 wt.% 17-4PH statinless steel nanopowders and 10 wt.% organic binder were mixed by a ball milling process. The green components with very clear gear shape were formed by filling the powder premix into the PDMS soft mold in surrounding at about $100^{\circ}C$. Cold isostatic pressing (CIP) was very potent process to decrease a porosity in the sintered microcomponent. The microgear fabricated by the improved process showed a good dimension tolerance of about 1.2%.

• Journal of Biosystems Engineering
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• v.29 no.4
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• pp.307-316
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• 2004

This study was conducted to develop a coating system for producing clean enriched rice. The nutritional components of such as brown rice, white rice, clean white rice, enriched rice of US, black rice of China, and rice with perfume of China, were analyzed and compared. Total protein lipid md minerals in brown rice were higher than those in the other rices. A nutrition premix with lysine, thiamine, niacine, calcium lactate, ferrous lactate, and rice starch was made for enriching white rice. A coating device consisted of a tumbler, two spraying nozzles, a rice mixer, etc was developed with the capacity of 1 ton/h. And far-infrared dryers of batch and continuous types were developed to dry hygienically the wet enriched rice. The percentages of lysine, thiamine, amino acid nitride, and Ca and Fe of the enriched rice samples produced in this study were, respectively, 4, 3, 3. 2, and 10 times higher than those of white rice, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.11
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• pp.1417-1423
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• 2004

The thickness of laminar flame and preheat zone was computed from equation with burning velocity and the temperature profile, which is obtained by using premix code of Chemkin program for ethanol-air mixture. The computations were carried out under the unburned gas pressure 0.5bar-30bar and temperature of 300k-700K at 1.0. A difference flame thickness showed between temperature profile and equation with burning velocity. The ratio of flame thickness derived from the equation was about 45∼65% of the temperature profile, and the thickness of preheat zone was about 67.1% of the flame thickness. The flame thickness was decreased by increasing the pressure and temperature, but the effect of pressure is more significant than the effect of temperature on the flame thickness. The flame thickness was predicted by using the following equation. X(mm) = $X_{st}$ (T/300)$^{-0}$.65/(P)$^{-0}$.68/ (0.5bar$\leq$P$\leq$30bar, 300K$\leq$T$\leq$700K)K)

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1171-1177
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• 2008

This study was undertaken to classify Enterobacter sakazakii isolates from 13 powdered infant formula products, 25 powdered weaning diet products, and 33 weaning diet ingredients on polymerse chain reaction (PCR) methods. The numbers of the isolates from 1 powdered infant formula product, 7 powdered weaning diet products, and 6 weaning diet ingredients were 1, 14, and 8, respectively. The contaminated ingredients were 1 rice powder, 2 millet powders, 2 vegetable powders, and 1 fruit and vegetable premix. PCR with the primer of repetitive extragenic palindromic element (REP-PCR) and random amplification of polymorphic DNA(RAPD) were effective in discriminating among the isolates, but tRNA-PCR and PCR with the primer of l6S-23S internal transcribed spacer (ITS-PCR) were not. Some of E. sakazakii isolates from vegetable powders, fruit and vegetable premix, and millets powders were classified into the clonal groups based on the DNA patterns in the REP-PCR and RAPD analysis. A close genetic relationship among the isolates from some of the powdered weaning diet products and the rice powder was also detected in the cluster analysis based on the DNA patterns in RAPD.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3717-3722
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• 2021

In this study, the recovery rates of the dissolution method for radioactivity analysis of expandable polystyrene (EPS) with a liquid scintillation counter (LSC) using tetrahydrofuran (THF), toluene, and acetone as solvents were estimated. The detection efficiency calibration curve for each solvent was derived. Two methods-the volumetric ratio method and the quenching agent method-were used to prepare quench source sets, and calibration curves were derived by linking the data from the two quench source sets. The R² value of the calibration curve for THF was found to be 0.984. The relationship between the mass of dissolved EPS and the quench level was estimated: the quench level increased as the mass of dissolved EPS increased. Premix and postmix dissolution methods were tested. The recovery rates using THF with the premix method were 84.9 ± 0.9% and 96.5 ± 1.5% for ³H and ¹⁴C, respectively. Furthermore, the stability of the recovery rate over time when using THF was evaluated. The dissolution method with the premixed solution exhibited a more stable recovery rate over time. The dissolution methods were found to be applicable for analysis using LSC, and THF was found to be the most suitable solvent for the proposed method.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.4
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• pp.314-319
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• 2010

This study determined the proper inclusion levels of squid liver powder (SLP) - soy protein concentrate (SPC) premix as a fish meal (FM) substitute in the diet for juvenile olive flounder (Paralichthys olivaceus). All the experimental diets were formulated to be isonitrogenous (50% crude protein) and isocaloric (17.1 kJ energy $g^{-1}$ diet). Five diets were formulated with SLP-(SPC) replacing 0, 25, 50, 75, and 100% of the FM (SLP $(SPC)_0$, SLP $(SPC)_25$, SLP $(SPC)_50$, SLP $(SPC)_75$, and SLP $(SPC)_100$, respectively). Triplicate groups of 12 fish averaging $5.56{\pm}0.10\;g$ ($mean{\pm}SD$) were fed one of the five experimental diets for 7 weeks. The weight gain (WG), specific growth rate (SGR), feed efficiency (FE), and protein efficiency ratio (PER) of fish fed SLP $(SPC)_0$ were significantly (P<0.05) higher than those of fish fed SLP $(SPC)_50$, SLP $(SPC)_75$ and SLP $(SPC)_100$, while those of fish fed SLP $(SPC)_0$ and SLP $(SPC)_25$ were similar. The whole-body crude protein content of fish fed SLP $(SPC)_0$ was significantly (P<0.05) lower than that of fish fed SLP $(SPC)_50$, SLP $(SPC)_75$, and SLP$(SPC)_100$, while those of fish fed SLP $(SPC)_0$ and SLP $(SPC)_25$ were similar. The whole-body crude lipid of fish fed SLP $(SPC)_0$ was significantly (P<0.05) lower than that of fish fed SLP $(SPC)_50$ and SLP $(SPC)_75$, while those of fish fed SLP $(SPC)_0$, SLP $(SPC)_25$ and SLP $(SPC)_100$ were similar. Based on the fish growth performance results obtained from this study, the SLP (SPC) premix can substitute up to 25% of the FM in the diets of juvenile olive flounder.