• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.252-253
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• 2006

The fabrication of complex-shaped parts out of Co-Cr-Mo alloy and 316L stainless steel by three-dimensional printing (3DP) was studied using two grades of each alloy with average particle size of 20 and $75\;{\mu}m$, respectively. To produce sound specimens, the proper 3DP processing parameters were determined. The sintering behavior of the powders was characterized by dilatometric analysis and by batch sintering in argon atmosphere at $1280^{\circ}$ for 2h. The 3DP process has successfully produced complex-shaped biomedical parts with total porosity of 12-25% and homogenous pore structure, which could be suitable for tissue growth into the pores.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제34권3호
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• pp.257-276
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• 2020

본 연구에서는 순열과 조합 영역에서 예비수학교사들의 MKT 수준을 알아보고, 예비교사들의 MKT 함양을 위한 프로그램(MKT-DP)을 개발·실행한 후 그 효과를 검증함으로써 예비교사 교육 프로그램의 개발 및 실행에 대한 시사점을 도출하고자 하였다. MKT 사전 검사 결과에 의하면, 본 연구에 참여한 예비교사들의 순열과 조합 영역의 MKT 수준이 높지 않음을 알 수 있었고, 특히 SCK와 KCT의 수준은 상당히 낮은 것으로 나타났다. 사전, 사후 MKT 검사 분석 결과 KCT 범주에서만 유의미한 차이가 나타나 본 연구에서 개발한 MKT-DP는 예비수학교사들의 KCT를 함양시키는데 효과적임을 알 수 있었다. 3가지 하위 범주(CCK, SCK, KCS)에 대해서는 사전, 사후 검사 간에 통계적으로 유의미한 차이가 나타나지 않았지만, 사전 검사에 비해 사후 검사에서 어느 정도의 수준 상승이 이루어진 것으로 나타나, MKT 전반에 걸쳐서 MKT-DP의 긍정적 영향력을 기대해 볼 수 있다.

• 한국식품과학회지
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• 제28권3호
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• pp.521-527
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• 1996

세 품종의 강낭콩 전분에 대하여 분자구조적 측면에서 그 특성을 조사하였다. 전분의 아밀로오스 함량과 ${\beta}$-아밀라아제 분해한도는 Pink종이 다른 종에 비하여 다소 높았다. 그리고 아밀로펙틴의 사슬분포는 ${\overline{DP}$60 이상의 초장사슬, ${\overline{DP}}45{\sim}60$인 B 사슬, 그리고 ${\overline{DP}}10{\sim}20$인 A 사슬로 분포하였으며, 그 분포도는 품종별로 차이를 보였는데, Pink종은 B사슬, Red종은 초장사슬, 그리고 White종은 A 사슬이 다른 종에 비하여 더 많이 분포하였다. 전분의 딴 가수분해(2.2N HCI는 3 단계로 일어났으며, 각 품종간에는 가수분해 속도와 요오드 반응에서 다소 차이를 보였다. 전분은 산처리에 따라 아밀로오스와 무정형인 아밀로펙틴의 ${\alpha}$-1.6 결합이 점차 분해되어, 결국은 결정성을 가진 ${\overline{DP}}$ 20 정도의 사슬로 남았다. 이러한 결과로부터 강낭콩은 품종에 따라 전분의 분자구조가 다름을 알 수 있었다.

• 한국정밀공학회지
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• 제27권11호
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• pp.46-56
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• 2010

The present research works investigated into the low velocity impact characteristics of DP 780 high strength steel sheet with 1.7 mm in thickness subjected to free boundary condition using three-dimensional finite element analysis. Finite element analysis was carried out via ABAQUS explicit code. Hyper-elastic model and the damping factor were introduced to improve an accuracy of the FE analysis. An appropriate FE model was obtained via the comparison of the results of the FE analyses and those of the impact tests. The influence of the impact energy and nose diameter of the impact head on the force-deflection curves, impact time, absorption characteristics of the impact energy, deformation behaviours, and stress-strain distributions was quantitatively examined using the results of FE analysis. The results of the FE analysis showed that the absorption rate of impact energy lies in the range of the 70.7-77.5 %. In addition, it was noted that the absorption rate of impact energy decreases when the impact energy increases and the nose diameter of the impact head decreases. The local deformation of the impacted region was rapidly increased when the impact energy was larger than 76.2 J and the nose diameter was 20 mm. A critical impact energy, which occur the instability of the DP780, was estimated using the relationship between the plastic strain and the impact energy. Finally, characteristics of the plastic energy dissipation and the strain energy density were discussed.

• 한국표면공학회지
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• 제45권3호
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• pp.130-135
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• 2012

Hydrogen charging was electrochemically conducted at high strength DP steels and TRIP steel with varying charging time. The penetration depths and the mechanical properties with charging conditions were investigated through the distribution of micro-hardness and the microstructural observation of the subsurface zone. The micro-Vickers hardness was measured to evaluate the hydrogen embrittlement of subsurface zone in addition to the microscope investigation. It was shown that the hydrogen amounts decreased in DP steels and TRIP steel with increasing hydrogen charging time. As shown by micro-Vickers hardness test and small punch test results, micro-Vickers hardness and SP energy for DP steels and TRIP steel decreased with increasing hydrogen charging time, for constant value of charging current density. SEM investigation results for the hydrogen contained samples showed that the major fracture behavior was brittle fracture which results in dimples on fractured surface and the size of dimples were decreased with increasing hydrogen charging time. These results indicate that hydrogen embrittlement is the major cause for the fracture of high strength steels and also micro-Vickers hardness test and small punch test is a valuable test method for hydrogen embrittlement of high strength sheet steels.

• 대한수의학회지
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• 제55권2호
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• pp.111-116
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• 2015

In the present study, the effects of different photoperiods on stress, immunity, and hematological parameters in ICR mice were evaluated. Fifty male ICR mice 7 weeks old (body weight, $27.3{\pm}2.5g$) were divided into five groups: DP-0 (0/24-h light/dark cycle), DP-6 (6/18-h light/dark cycle), DP-12 (12/12-h light/dark cycle), DP-18 (18/6-h light/dark cycle), and DP-24 (24/0-h light/dark cycle). During the experimental period, no significant differences in body weight or feed intake were observed between the groups. Hematological analysis revealed that white blood cell, red blood cell, and hemoglobin values for the DP-0 group were significantly different compared to those of the other groups. After 28 days, no significant difference in serum cortisol concentration was observed among the groups, but serum cortisol levels increased in a light exposure-dependent manner. Total serum immunoglobulin G (IgG) concentrations of the DP-0 and PD-6 groups were significantly increased compared to those of the other groups (p < 0.05), and serum total IgG levels decreased in a light exposure-dependent manner. Results of the present study indicated that various photoperiods affect hematological parameters and total serum IgG levels in ICR mice while having no significant effects on body weight, feed intake, or cortisol levels.

• Journal of the Korean Wood Science and Technology
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• 제24권4호
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• pp.82-86
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• 1996

This study was performed to elucidate the effect of degree of substitution and degree of polymerization of CMC on the rheological characteristics of coating color which is consisted of calcium carbonate as pigment. The results were as follows: 1. It appeared that DP of CMC rather DS has an effect on the low shear viscosity of coating color. 2. According as shear rate increased, the effect of DP and DS on high shear viscosity of coating color decreased. 3. According to increasing DS and DP, the water retention of coating color increased.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2014년도 춘계학술대회
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• pp.43-45
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• 2014

DPO(Dynamic positioning Operator)는 Dynamic positioning 기능이 있는 선박에 승선하는 항해사로서 항해, 정박 당직 뿐만 아니라 Dynamic positioning이 요구되는 다양한 offshore 작업시에 DP 당직을 수행한다. 정식 DPO가 되기 위하여는 SCTW 항해사 면허뿐만 아니라 NI 혹은 NMD에서 규정한 training 과정을 이수하여 DP limited 혹은 DP unlimited certificate를 취득하여야 한다. 본 연구에서는 1982년부터 업계 표준 DPO의 training과 certification을 담당하고 있는 NI (Nautical Institute) 산하 DPTEG(Dynamic Positioning Training Executive Group)의 DPO 양성과정을 조사하였다. 특히 업계의 보다 현실적인 DPO training 과정에 대한 요구에 대응하여 2014년 3월에 발표되어 2015년 1월1일부터 발효될 더욱 강화된 training과 verification 절차를 담은 새로운 DPO training scheme을 분석하여 한국 해기사들이 DPO로서 offshore sector에 진출하기 위한 방안을 제시하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제3권3호
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• pp.231-242
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• 1990

A study is reported which investigated the additive nature of digestible energy (DE) from dietary nutrients and to estimate the relative energy values of different energy-yielding nutrients in practical trout diets. A growth study was conducted over 12 weeks with 6 diets. Rainbow trout (Oncorhynchus mykiss) were fed diets once a day ad libitum. Digestible energy values determined and calculated had direct relationship indicating additive nature of such values for feed ingredients. Overall growth performance was best in a diet containing 33% digestible protein (DP) with a DP/DE ratio of 18.6. A reduction in digestible protein level with the same DP/DE rat io led to a significant decrease in growth and feed efficiency. The increase of 7% of lipid with concomitant decrease in protein resulted in the relative gain of 130% in growth and nutrient retention, suggesting that 1 g of lipid is equal to about 1.3 g of proteins in terms of net energetic value. Replacement of 10% of dietary lipid by carbohydrates led to a slight decrease in energy retention efficiency but to a great increase in lipid retention efficiency (130%) showing that dietary carbohydrates led to increased lipogenesis.

• 펄프종이기술
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• 제45권3호
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• pp.59-68
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• 2013

The cotton contains various impurities such as protein, wax, pectins, coloring matter, even though cotton has been a major source of pure cellulose. The purification processes have been commonly applied to obtain the pure cellulose. However the excessive purification treatments could lead to the damage in the cellulose structure which could result in the degradation of cellulose and the limited application of cotton cellulose. In this study, the changes in cellulose structural properties such as crystallinity and DP(degree of polymerization) by the various conditions of the purification processes were investigated. The less toxic agents such as hydrogen peroxide and sodium silicate were applied for the purification treatment in this study. The increase in the process times, the temperature and the applied amount of chemical agents resulted in the more purified cellulose. The DP of cotton cellulose was increased at the first weak conditions by the reduction of small molecules such as pectin, wax, and so on. Especially the 2 % addition amount of $H_2O_2$ with $Na_2SiO_3$ resulted in the higher value in the DP and the brightness compared to the 1.5 % addition amount of $H_2O_2$. However, the 4 % addition amount of $H_2O_2$ with $Na_2SiO_3$ showed the decreased value because of excessive treatment. In case of the changes in the crystallinity (Gjk), the highest value of the crystallinity was obtained by the 2% addition amount of $H_2O_2$ on the cotton cellulose, which showed similar with the change in the DP.