• 한국식품영양과학회지
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• 제31권6호
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• pp.999-1004
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• 2002

식염농도를 3, 5, 7 및 9%로 각각 조제한 2$^{\circ}C$의 염지액에 등심고기를 20일간 염지하면서 식염농도와 염지기간이 근원 섬유단백질의 추출성과 소편화도, 보수력, 식염함량 및 기호성에 미치는 영향을 검토하였다. 식염농도 3, 5 및 7%의 염지액에 염지한 등심고기 근원섬유단백질의 추출성과 보수력은 염지 20일까지, 근원섬유 소편화도는 염지 16일까지, 모두 식염농도가 높을수록 점점 높게 나타났으며, 9%의 염지액에 염지한 것은 일정한 경향을 보이지 않았다. 가열육의 색도는 염지액의 식염농도가 높을수록, 그리고 염지 16일까지 점점 양호하게 나타났다 염지액의 식염농도 3%에서는 염지육의 발색이 균일하게 되지 않았으며, 9%에서는 발색이 잘 되었으나 풍미와 종합적인 기호성이 좋지 않았다. 등심고기는 염지액의 식염농도5%에서 16일, 또는 7%에서 12일 염지하면 기호성이 우수하게 되었다.

• 소성∙가공
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• 제7권2호
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• pp.139-149
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• 1998

The technology of Semi-Solid Forging(SSF) has been actively developed to fabricate near net shape products using light and hardly formable materials. Generally the SSF process is composed of slug is compressed during a certain holding time in order to completely fill the die cavity and accelerate the solidification rate. The decision of compression time is important since it can affect microstructural characteristics, mechanical properties and shape of products.. In order to determine it proper overall heat transfer coefficient between the slug and dies should be investigated. This paper presents the procedure to find the overall heat transfer coefficient between the slug and dies by nonlinear optimization of temperature and solid fraction for a cylindrical slug at compression step in closed-die semi-solid forging. In finite ele-ment heat transfer analysis release of latent heat during solidification was considered. The influence of the predicted compression time on miscrostructural characteristics mechanimcal properties and shape of products is finally investigated by experiment.

• Journal of Information Display
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• 제10권2호
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• pp.62-67
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• 2009

To understand panel driving more accurately, the optical properties and their distributions in the LCD panel itself, excluding the backlight, were investigated by measuring the transmittance of a one-dot pixel as a function of time. First, the behavior of time-dependent transmittance was analyzed, and it was found that the off-state TFT was not in a steady state but in a transient state during the holding period. Second, the time average, max, min, and range values of the transmittance curves were examined by varying the common voltage level and gray scale. Third, the analysis of such properties was expanded to cover those of the entire panel in all the gray scales. Lastly, the relationship between their properties and distributions was also investigated along with the contour plots.

• Journal of Welding and Joining
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• 제23권2호
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• pp.52-58
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• 2005

This study was carried out to investigate the effect of bonding temperature and heating rate on transient liquid phase diffusion bonding of Ni-base superalloy. The heating rate was varied by $0.1^{\circ}C$/sec, $1^{\circ}C$/sec, $10^{\circ}C$/sec to the bonding temperatures $1100^{\circ}C,\;1150^{\circ}C,\;1200^{\circ}C$ under vacuum. As bonding temperature increased, maximum dissolution width of base metal increased, but a dissolution finishing time decreased. The eutectic width of insert metal in the bonded interlayer decreased linearly in proportion to the square root of holding time during isothermal solidification stage. The bonding temperature was raised, isothermal solidification rate slightly increased. As the heating rate decreased and the bonding temperature increased, the completion time of dissolution after reaching bonding temperature decreased. When the heating rate was very slow, the solidification proceeded before reaching bonding temperature and the time required for the completion of isothermal solidification became reduced.

• 한국세라믹학회지
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• 제49권6호
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• pp.535-541
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• 2012

ALC was fabricated using cement, lime, quartzite and a foaming agent via a hydrothermal reaction. ALC has various hydrothermal reaction products and many pores. The properties and colors of ALC surfaces were changed by various factors during ALC fabrication process. This study tested various staying times to analyze these phenomena. It was found that the staying time of green body influenced the properties of hydrothermal products and color of ALC surface. The longer staying time of green body, the lower tobermorite content and cumulative loss weight. An increase in holding time changed color and decreased whiteness of ALC surface. The relationship between whiteness and cumulative loss weight was very high (Coefficient, r = 0.95). It was surmised that tobermorite content was an important factor for enhancement of whiteness However, ettringite and quartzite did not contribute to whiteness.

• Journal of Animal Science and Technology
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• 제48권2호
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• pp.287-292
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• 2006

연도증진의 가장 일반적인 방법인 숙성을 통해 말고기의 육질과 관능적 특성이 어떻게 변화하는지를 조사하여 말고기의 적정 숙성기간을 제시하고, 국내 말고기의 냉장 유통에 대비한 기초자료를 확보하고자 제주마 24두의 등심을 4℃에서 25일간 숙성시키면서 육질과 관능적 특성을 조사하였다. 말고기 pH는 숙성기간에 따라 차이가 없었으며, 전단력은 저장 12일까지 유의적으로 감소하다가(P<0.05) 12일 이후 차이를 나타내지 않았다. 보수력, 가열감량 및 포장감량은 숙성기간이 경과할수록 증가하는 경향이였으며, 육색특성은 숙성기간이 경과할수록 명도(L*)와 적색도(a*) 값이 증가하는 경향을 보였다. 관능적 특성 중 풍미는 저장 7일에 가장 높은 수치를 나타내었고, 다즙성은 숙성 12일에 패널에 의해 가장 좋은 점수를 받았으며, 연도는 숙성 7일에 유의적인 증가를 보였으며(P<0.05) 이후 숙성기간에는 차이가 없었다. 숙성기간별 말고기에 대한 전체기호도는 숙성 7일에 유의적인 증가를 보인 후 숙성 18일까지 지속하다가 25일에 다소 감소하였다(P<0.05). 이상의 결과로 볼 때 말고기 등심의 최적숙성기간은 도축 후 9～14일로 나타났으며, 도축 후 20일 이후에는 기호성과 육질이 저하되는 결과를 보였다.

• 소성∙가공
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• 제7권3호
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• pp.215-224
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• 1998

A semi-solid forming has a lot of advantages compared to the die casting. squeeze casting and conventional forging. therefore, semi-solid forming process is now becoming industrial interest for the production of metal components and metal matrix composites. However the material behaviour in the semi-solid temperature range is not sufficiently known although it controls the whole process through forces and geometry evolutions because the behaviour of metal slurries is complex. The semi-solid materials(SSMs) fabricated under electric-magnetic stirring condition is necessary to be applicated in forming process. A reheating conditions were studied with the reheating time holding time and reheating temperatures. The microstructure of SSM(specimen size : d39${\times}$h85) at the condition of heating time 10min and heating temperature 590${\circ}C$ is the most globular and finest one. The microstructure of SSM(specimen size : d76${\times}$h60) reheated under the three step reheating conditions is most globular and finest.

• 열처리공학회지
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• 제27권2호
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• pp.72-78
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• 2014

Isothermal transformation behavior of a 10% Cr heat resistant steel fabricated by centrifugal casting process was investigated. Normalized specimen at $1100^{\circ}C$ for 1 hour was isothermally annealed at temperature range between $600^{\circ}C$ and $700^{\circ}C$ with various time. The annealed specimen had eutectoid structure which was generated along austenitic grain boundary during isothermal annealing. Areal fraction of eutectoid structure increased up to 25% after holding at $700^{\circ}C$ for 20 hours. It was observed that austenitic matrix was transformed to ferrite structure and fine $M_{23}C_6$ carbides with increase of annealing time. Time-temperature-transformation diagram of the centrifugally cast 10% Cr steel with 0.18 wt% C was plotted based on the results of isothermal transformation behavior.

• 대한산업공학회지
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• 제24권1호
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• pp.157-165
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• 1998

This paper considers the single-product production and transportation problem with discrete time, dynamic demand and finite time horizon, an extension of classical dynamic lot-sizing model. In the model, multiple freight container types are allowed as the transportation mode and each order (product) placed in a period is shipped immediately by containers in the period. Moreover, each container has type-dependent carrying capacity restriction and at most one container type is allowed in each shipping period. The unit freight cost for each container type depends on the size of its carrying capacity. The total freight cost is proportional to the number of each container type employed. Such a freight cost is considered as another set-up cost. Also, it is assumed in the model that production and inventory cost functions are dynamically concave and backlogging is not allowed. The objective of this study is to determine the optimal production policy and the optimal transportation policy simultaneously that minimizes the total system cost (including production cost, inventory holding cost, and freight cost) to satisfy dynamic demands over a finite time horizon. In the analysis, the optimal solution properties are characterized, based on which a dynamic programming algorithm is derived. The solution algorithm is then illustrated with a numerical example.

• International Journal of Precision Engineering and Manufacturing
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• 제4권2호
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• pp.49-56
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• 2003

As semi-solid forging (SSF) is compared with conventional casting such as gravity die-casting and squeeze casting, the product without inner defects can be obtained from semi-solid forming and globular microstructure as well. Generally, SSF consists of reheating, forging, and ejecting processes. In the reheating process, the materials are heated up to the temperature between the solidus and liquidus line at which the materials exists in the form of liquid-solid mixture. The process variables such as reheating time, reheating temperature, reheating holding time, and induction heating power has large effect on the quality of the reheated billets. It is difficult to consider all the variables at the same time for predicting the quality. In this paper, Taguchi method, regression analysis and neural network were applied to analyze the relationship between processing conditions and solid fraction. A356 alloy was used for the present study, and the learning data were extracted from the reheating experiments. Results by neural network were in good agreement with those by experiment. Polynominal regression analysis was formulated using the test data from neural network. Optimum processing condition was calculated to minimize the grain size and solid fraction standard deviation or to maximize the specimen temperature average. Discussion is given about reheating process of row material and results are presented with regard to accurate process variables fur proper solid fraction, specimen temperature and grain size.