• 한국인쇄학회지
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• 제26권1호
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• pp.29-38
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• 2008

Print-through is one of the most important attributes of print quality and has long been a subject to study. However, some aspects of print through are still in need to be enlighten. In this paper, different kinds of evaluating methods for print through are compared using densitometry, brightness, and image analysis. Printing conditions including ink feed, drying condition, and emulsification rate are systematically changed to effect print-through both on uncoated and coated commercial papers. Also several inks from different makers are introduced and compared in terms of print-through propensity. From the results, densitometry is not a good indicator for print through on the papers in this study. Ink feed has a strong effect on print through, especially for uncoated paper and should be considered in a point of optimum ink feed level in real world. Contribution of faster ink(oil) absorption seems to be more competitive than that of ink(oil) evaporation resulting in severer print-through for hot drying process. It is shown that ink-water emulsification rate increases print through at mild level but easy to decrease it with lower density due to the increase of water contents in emulsion. It is believed that the effect of absorption overwhelms that of density drop at mild emulsification level. This study does not include the effect of ink attributes in detail but shows that distinctive differences in print through may be resulted from various ink-makers and is finalized with some suggestions.

• 한국수산과학회지
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• 제42권3호
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• pp.262-267
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• 2009

Two 15-week feeding trials were conducted to investigate feeding rate and feeding frequency for growth of sub-adult flounder in suboptimal water temperature ($12^{\circ}C$). In the first experiment, duplicated groups of fish (initial mean weight of 279 g) were fed a extruded pellet once a day at the different feeding rates of 0.1, 0.15, 0.2, 0.3% body weight per day (BW/d), and satiation (0.32% BW/d). Weight gain and feed efficiency were increased significantly (P<0.05) with increase in feeding rates from 0.1 to 0.3% BW/d, but there were no significant differences in weight gain and feed efficiency of fish fed the diet between 0.3% BW/d and to satiation. Crude protein content of dorsal muscle of fish fed the 0.1% BW/d diet was significantly (P<0.05) lower than that of the other groups. In the second experiment, duplicated groups of fish (initial mean weight of 281 g) were fed to apparent satiation with a extruded pellet at three different feeding frequencies (one meal every two days, one meal a day and two meals a day). Weight gain, feed efficiency and condition factor of fish fed one meal every two days were significantly (P<0.05) lower than those of fish fed one meal and two meals a day, but there were no significant differences in weight gain, feed efficiency and condition factor of fish fed between one meal and two meals a day. Based on the results of this study, optimum feeding frequency is one meal a day with satiation feeding for growth and feed efficiency of sub-adult flounder (270-350 g) in suboptimal water temperature ($12^{\circ}C$).

• 동력기계공학회지
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• 제3권4호
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• pp.63-68
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• 1999

The determination of the optimal machining parameters in metal cutting, such as cutting speed, feed rate, and depth of cut, is an important aspect in an economic manufacturing process. The main objective in general is either to minimize the production cost or to maximize the production rate. Also there are constraints on all the machining operations which put restrictions on the choice of the machining parameters. In this paper as an objective function the production cost is considered with two constraints, surface finish and cutting power. Genetic Algorithm is applied to determine the optimum machining parameters, and the effectiveness of the applied algorithm is demonstrated by means of an example, turning operation.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.109-122
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• 2018

This work highlights extraction and removal of Lignosulfonate using sunflower oil-Tri-n-octylamine (TOA) system in bulk liquid membrane transport. Maximum extraction and recovery percentages of 92.4% and 75.2% were achieved. Optimum manifold operating conditions were: 4 vol.% TOA, $2{\pm}0.1$ feed phase pH, 300 rpm stirring speed, at $40^{\circ}C$ with 0.2 (M) $Na_2SO_4$ solution. 1:2 (organic/aqueous) and 1:1 (aqueous/aqueous) phase ratios produced best results. Extraction (36.85 kJ/mol) was found to be intermediate controlled and stripping (54.79 kJ/mol) was chemical reaction controlled. Kinetic estimation of data with higher rate constants for stripping vis-${\grave{a}}$-vis extraction showed latter to be rate determining.

• 한국재료학회지
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• 제25권9호
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• pp.442-449
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• 2015

The effects of coating parameters were investigated in wear resistance coatings of Diamalloy-406 on Inconel 718 to obtain an optimum coating condition by high velocity oxy-fuel spraying. The coating parameters, the flow rates of source gases (hydrogen and oxygen), the powder feed rate, and the spray distance, were designed by the Taguchi method. The optimal conditions were determined: oxygen flow rate 34 FRM, hydrogen flow rate 57 FRM, powder feed rate 35 g/min, and spray distance 7 inch. Friction coefficients of the coating and the substrate decreased with an increasing sliding surface temperature from $25^{\circ}C$ to $450^{\circ}C$. The friction coefficient of Diamalloy-4006 coating decreased as the sliding surface temperature increased from $0.43{\pm}0.01$ at $25^{\circ}C$ to $0.29{\pm}0.01$ at $450^{\circ}C$. The wear trace and wear depth of the coating were smaller than the substrate at all temperatures tested. The relationship between spray parameters and wear resistance was discussed extensively, based on the measured roughness, hardness, and porosity in each coating.

• 한국초지조사료학회지
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• 제30권3호
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• pp.205-216
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• 2010

본 시험은 청보리, 밀, 호밀, 트리티케일, 귀리 등 총체맥류 주요 품종에 대하여 봄 파종시 출수 여부, 생육, 수량 및 사료가치 등을 적기 파종과 비교하고자 2008/2009년에 충남농업기술원(예산) 밭 사료포에서 수행되었다. 시험초종 및 품종은 청보리(영양, 파성 I), 밀(금강, 파성 II), 호밀(곡우, 파성 III 추정), 트리티케일(신영, 파성 III 추정), 귀리(삼한, 파성 II 추정)이었고, 파종기는 가을 적기파종(10월 18일)과 봄 파종(2월 23일, 3월 10일)을 두었다. 출수기는 봄 파종시 가을 적기 파종에 비하여 청보리, 밀, 호밀, 트리티케일 등은 약 16~20 일, 귀리는 약 9일 늦었다. 봄 파종시 수확시기는 영양 보리(황숙기) 6월 8일, 곡우 호밀(출수 후 10일) 5월 25일, 금강 밀(황숙기), 신영 트리티케일(유숙기) 및 삼한 귀리(유숙기)는 6월 17일경 이었다. 봄 파종은 가을 파종에 비하여 출현기부터 출수기까지의 적산온도의 감소가 컸고, 파종기~출현기, 출수기부터 성숙기까지의 적산온도는 큰 차이가 없었다. 전체 경수에서 출수된 이삭수의 비율은 영양 보리, 금강 밀, 신영 트리티케일, 삼한 귀리 등은 62.0~73.1% 로서 정상적으로 출수되었고, 곡우호밀은 56.0%로서 출수되지 않는 분얼이 많았다. 봄 파종시 건물수량은 삼한 귀리> 신영 트리티 케일> 영양 보리> 금강 밀> 곡우 호밀 순으로 많았고, 가을파종에 비하여 영양 보리 71.7%, 금강 밀 60.6%, 곡우 호밀 46.2%, 신영 트리티케일 70.2%, 삼한 귀리 110.9% 수준이었다. 총체맥류를 봄에 파종하면 가을 파종에 비하여 ADF 함량, NDF 함량 및 조단백질 함량이 증가하는 것으로 나타났고, 가소화건물함량과 상대사료가치는 낮아졌다. 봄 파종시 평균 가소화 건물수량은 삼한 귀리> 신영 트리티케일> 영양 보리> 금강 밀> 곡우 호밀 순으로 높았고, 가을에 파종한 것에 비하여 영양 보리, 금강 밀, 곡우 호밀, 신영 트리티케일은 모두 감수되었고, 삼한 귀리는 증수되었다. 따라서 예취시기 등을 고려하지 않는다면 봄 파종은 귀리가 가장 알맞은 것으로 나타났고, 다음은 신영 트리티케일, 영양 보리 순이었으며, 곡우 호밀은 부적합한 것으로 판단되었다. 또한 총체 맥류의 봄 파종 및 재배는 파성을 소거할 필요가 있으므로 2월 말(경칩 전) 얼음이 풀리는 대로 가능하면 빨리 파종하여 낮은 지온으로 종자 상태에서 춘화처리가 되도록 할 필요가 있었다.

• Structural Engineering and Mechanics
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• 제73권5호
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• pp.501-513
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• 2020

In the present work, the optimization of machining parameters to achieve the desired technological parameters such as surface roughness, tool radial vibration and material removal rate have been carried out using response surface methodology (RSM). The hard turning of EN19 alloy steel with coated carbide (GC3015) cutting tools was studied. The main problem faced in manufacturer of hard and high precision components is the selection of optimum combination of cutting parameters for achieving required quality of surface finish with maximum production rate. This problem can be solved by development of mathematical model and execution of experiments by RSM. A face centred central composite design (FCCD), which comes under the RSM approach, with cutting parameters (cutting speed, feed rate and depth of cut) was used for statistical analysis. A second-order regression model were developed to correlate the cutting parameters with surface roughness, tool vibration and material removal rate. Consequently, numerical and graphical optimization were performed to obtain the most appropriate cutting parameters to produce the lowest surface roughness with minimal tool vibration and maximum material removal rate using desirability function approach. Finally, confirmation experiments were performed to verify the pertinence of the developed mathematical models.

• 한국수산과학회지
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• 제44권5호
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• pp.490-498
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• 2011

Two consecutive feeding trials investigated the effects of feeding rate and pellet expansion by water-soaking on the growth performance, blood components and histology of olive flounder Paralichthys olivaceus. The first two experiments were carried out to determine the effects of pellet expansion and feeding rate. In the first experiment, growth performance, feed utilization and survival of fish were not significantly affected by pellet expansion for six weeks. There were no significant differences in hematocrit, hemoglobin, aspartate aminotransferase, alanine aminotransferase, glucose and total protein of fish fed the expanded pellet. However, whole-body lipid content of fish in the non-expanded group was significantly higher than that in the expanded group. Histological analysis of the anterior intestine revealed that fish in the expanded group had shorter and smaller mucous folds. These results indicate that pellet expansion had no beneficial effect in terms of growth performance, feed utilization and fish health. In the second experiment, weight gain and feed efficiency were significantly increased as feeding rate increased from 0 to 2.5% body weight per day (BW/d), but there were no significant differences in weight gain or feeding efficiency in fish fed the expanded pellet at ratios of 2.5% BW/d and satiation for three weeks. Plasma aspartate aminotransferase activity of fish fed the expanded pellet at a ratio of 2.5% was significantly lower than that of starved fish. Histological analysis of the anterior intestine revealed that fish in the 0% group had shorter mucous folds. Broken-line regression analysis suggested that the optimum juvenile olive flounder feeding rate was 3.5% BW/d during the low temperature season ($16-17^{\circ}C$).

• 한국수산과학회지
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• 제55권6호
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• pp.886-893
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• 2022

This study was conducted to evaluate the effects of dietary silymarin supplementation on the growth performance, feed utilization, innate immunity and antioxidant capacity of Pacific white shrimp Litopenaeus vannamei. Four experimental diets were formulated to contain 0, 0.025, 0.05 and 0.1% silymarin (designated as Con, S0025, S005 and S01, respectively). Triplicate groups of shrimp (initial body weight: 0.70 g) were fed each of the diets for 6 weeks. After the feeding trial, weight gain and specific growth rate were significantly higher in silymarin-supplemented groups compared to Con group. Dietary silymarin significantly enhanced protein efficiency ratio of S01 group and reduced feed conversion ratio of S005 and S01 groups. Phenoloxidase and anti-protease activities were significantly higher in S01 group compared to Con group. Glutathione peroxidase and catalase activities were significantly higher in silymarin-supplemented groups compared to those of Con group. The results of this study indicate that dietary silymarin could improve the growth performance, feed utilization, innate immunity and antioxidant capacity of Pacific white shrimp. The optimum level of silymarin in diet for Pacific white shrimp is suggested to be ≥0.025%.

• 한국수산과학회지
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• 제19권6호
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• pp.581-585
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• 1986

부산수산대학 어류양식연구실 순환여과식장치내에서 1985년 8월 28일부터 9월 17일까지 DO농도에 대한 이스라엘계 잉어의 성장효과를 알아보기 위한 실험이 수행되었다. 순환여과사육장치중의 5개 탱크를 이용하여 동일조건하에서 DO농도 2.0, 2.5, 3.0, 3.5 및 4.0mg/l로 구분하여 실험했고 실험어는 평균 300g으로 각 탱크에 200kg씩 방양 사육한 결과는 다음과 같았다. DO 3.5mg/l 구에서 사료계수 1.57, 일일성장율 $1.411\%$로서 가장 좋은 성장결과를 얻었으며 DO 4.0mg/l 구에서는 사료계수 1.63, 일일성장률 $1.365\%$를 나타냈다. 그리고 사료섭취량은 이 두 실험구에서 거의 같았으며 DO 3.0mg/l 농도이하에서는 성장율과 사료섭취량이 현격히 감소했다. 실험기간동안 2.0mg/l와 2.5mg/l 농도에서는 사료섭취가 활발하지 않았으며 사료를 먹고난 후 대부분이 주수구에 몰려 산소부족현상을 나타냈고, 4.0mg/l 구에서는 5미가 columnaris 병에 의한 아가미 부식병으르 폐사했다. 이상의 결과를 종합해 볼 때 순환여과식장치내에서 평균수온 $27.5^{\circ}C$에서 DO 3.5mg/l와 4.0mg/l에서 거의 같은 좋은 성장률과 사료효율을 나타냈으므로 DO 3.5mg/l 이상만 유지시키면 에너지 효율면에서 경제적이 된다고 사료되고, 4.0mg/l 또는 그 이상에서는 energy의 낭비를 초래하고, 또한 부작용이 나타날 가능성이 있지만 이에 대해서는 더욱 연구해 볼 필요가 있다.