• Korean Journal of Clinical Laboratory Science
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• v.47 no.4
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• pp.237-242
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• 2015

The coagulation factor activity compared two groups of the lower 10% (29.1~30.9 sec) and the upper 10% (38.0~41.9 sec) of the normal reference range of aPTT. The aim of this study was to investigate the influence of sex, age, and ABO blood type on coagulation factor activity. There was significant difference in the activity of the coagulation factor assay based on age. The VIII (p<0.0001) and IX (p=0.0050) in the lower group of samples from those over sixty years of age is higher than from those under sixty. In contrast, XII (p=0.0285) for samples over sixty was lower than for samples under sixty. While in the upper group V (p=0.0219), VIII (p=0.0005), and IX (p=0.0014) for samples from the over sixty group was higher than those under sixty. In the case of activity of coagulation factor between O and non-O blood type, VIII (p<0.001) activity of the non-O blood type was higher than that of the O blood type in the both groups. The XII (p=0.016) activity of non-O blood type was lower than that of O blood type in the upper group. According to the multiple logistic regression analysis, when other variables are under the same conditions between lower and upper groups, there is a strong possibility for the lower group when activity of V (p=0.001), VIII (p<0.001), X (p<0.001) and XII (p<0.001) is increased. Furthermore, there is also a strong possibility of upper group when activity of II (p=0.004) and IX (p=0.012) is increased. However, no significant difference in between sex, age and XI was observed.

• Journal of the Korean Magnetics Society
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• v.1 no.1
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• pp.25-29
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• 1991

It has been found that the as-quenched ribbons of $Sm_{x}Fe_{100-x-y}Ti_{y}(3.8{\leq}x{\leq}11.5,\;3.8{\leq}y{\leq}19.2)$ are composed of metastable $TbCu_{7}-type$ structure, ${\alpha}-(Fe,\;Ti),\;Fe_{2}Ti$ and an unknown phase accompanying strong diffraction line at $d=2.14{\AA}$. The metastable $TbCu_{7}-type$ phase, which was formed by rapid quenching, did not transform fully to the stable phases after annealing at $850^{\circ}C$ for 45 minutes except the one existed in $SmFe_{11}Ti$ melt-spun ribbon. The $SmFe_{11}Ti$ melt-spun ribbon, annealed at $850^{\circ}C$ for 45 minutes in vacuum, was found to be composed of $ThMn_{12}$. $\alpha$-(Fe, Ti) and $Fe_{2}Ti$ phases. The formation of $\alpha$-(Fe, Ti) and $Fe_{2}Ti$ phases in this melt-spun ribbon was due to the evaporation of Sm atoms during the high temperature annealing. The atomic ratios for the surface and the inside of $SmFe_{11}Ti$ melt-spun ribbon annealed in vacuum were $SmFe_{25.8}Ti_{2.6}$ and $SmFe_{11.7}Ti_{1.0}$ respectively. It is thought to be that much of $\alpha$-(Fe, Ti) and $Fe_{2}Ti$ phases exist on the surface of ribbon.

• The Journal of the Acoustical Society of Korea
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• v.17 no.2
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• pp.79-83
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• 1998

높은 온도에서 금속물질이 응고되는 동안에 물질의 구조는 결정성장속도비율에 따 라 크게 좌우된다. 유도초음파를 기초로 한 펄스-에코 초음파실험기술과 함께 고체-액체 경 계면의 위치와 속도를 실시간으로 측정할 수 있어 고체화되는 동안의 용광로 파라메터들을 조절하는데 사용될 수 있다. 실험은 Bridgman형의 용광로에서 CuMn-막대시료에 대하여 서로 다른 냉각비율로 수행되었다. 열적평형상태에서 경계면의 위치에 대한 측정분해능은 약10㎛이다.

• Journal of Korea Foundry Society
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• v.12 no.1
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• pp.51-61
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• 1992

주조시 주형내의 유동해석을 위해서는 시간에 따라 변화하는 자유표면 위치에 대한 정확한 정보가 요구되는 관계로 난제로 여겨져 왔다. 따라서 대부분의 연구는 초기치 속도를 정의하기 위해서 순간충입(instantaneous filling)을 가정하여 수치 해석을 하였던 것이다. 본 연구는 Modified Solution Algorithm-Volume of Fluid Method (MSOLA-VOF)를 개발하는 주조시 주형내의 유동을 수치적으로 해석하며, 유속이 수평 주조, 수직 주조의 경우에 어떤 영향을 미치는가에 대하여 연구하였다. 결론으로 응고 연구에 있어서 초기의 순간충입은 비현실적인 가정이라는 것이 밝혀졌으며, 충입시 초기 속도 분포와 결정 생성은 밀접한 관계가 있음을 알 수 있었다.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.4
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• pp.547-553
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• 2007

The physicochemical and functional properties of tofu prepared with kanghwang(Curcuma aromatica Salab.) were investigated, in order to study the effects of six different commercial coagulants. The coagulant concentrations were determined as 0.3% GDL, 0.3% $MgCl_2$, 1.0% $CaCl_2$, 1.5% $CaSO_4$, 0.45% mixed coagulant, and 1.5% Milky-Mg by pre-experiments. Also, the optimum concentration for the added kanghwang(Curcuma aromatica Salab.) was chosen as 0.01%. The yields of the kanghwang tofu prepared with Milky-Mg, mixed, and GDL coagulants were higher than those prepared with $MgCl_2$, $CaCl_2$, and $CaSO_4$. The pH of the kanghwang tofu prepared with the $MgCl_2$ coagulant was higher than when made with the other coagulants. The turbidity of the kanghwang tofu was highest when it was coagulated with GDL, and moisture content was highest or the of kanghwang tofu coagulated with $CaCl_2$. In the color analysis of the kanghwang tofu, the $L^{***}$ value was highest with the Milky-Mg coagulant, while the $a^{***}$ value was highest and the b value lowest with the GDL coagulant. For the textural properties, the hardness results were in the order of $CaSO_4$ > $CaCl_2$ > $MgCl_2$ > mixed > GDL > Milky-Mg, springiness, gumminess, and brittleness were highest in the tofu coagulated with Milky-Mg. For the overall acceptability of the sensory properties, the Kanghwang tofu that was made using the mixed coagulant had the highest score.

• Journal of Welding and Joining
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• v.15 no.1
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• pp.26-35
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• 1997

본 연구에서는 GTAW 및 GMAW 공정에서 용접부의 열 및 물질유동해석을 수행하기 위한 지배방정식, 해석방법 및 절차를 제시하였으며, 또 실제로 해석한 결과를 에제로 살펴보았다. 그러나 용접공정은 매우 복잡한 물리적 현상을 야기하기 때문에 용접부 수치해석 모델 설정 및 해석의 수행은 용이한 일은 아니다. 그렇지만 이 분야의 연구는 용접 구조물에 대해서 사전에 용접조건 설정을 위한 실제 용접 작업 수행을 하지 않고 용접부 형상, 결함, 냉각속도, 응고 등의 예측을 위한 매우 효과적이고 경제적인 방법으로 사료되기 때문에 용접 분야에 종사하는 관련 연구자들의 관심이 한층 더 요망된다.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.42-44
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• 2004

산업용 가스터빈의 버켓용 Ni기 초내열합금 GTD-111의 수리기술로서 천이액상확산접합법(Transcient Liquid Diffusion Bonding Process, 이하 TLP접차법)이 각광받고 있다. 그러나 이 방법은 등온응고 완료까지 장시간이 소요되므로 접합시간을 단축할 수 있는 공정 개발이 필요하다. (중략)

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.1
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• pp.11-18
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• 1996

Grown-in defects like OISF and FPD in the large diameter(> 8 inch)of silicon crystal are characterized. It was revealed that the presence of the ring-patterned OISF would deterorate the minority life time of the silicon crystal. Through the cooling experiment from the $1250^{\circ}C$, the nucleation of the OISF was confirmed to follow the homogeneous nucleation and growth process. In addition to OISF nucleus, crystal originated particle, which was known to be closely related with FPD (Flow Pattern Defects), was found to depend on the pulling rate of the crystal. Combination of the lower rate of the pulling and the faster cooling near the $950^{\circ}C$ is proposed to be effective method in reducing the generation of these grown-in defects.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.2
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• pp.45-50
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• 2005

During oxidation process, several type of defects are formed on the surface of the silicon crystal which was damaged mechanically before oxidation. As the size of abrasive particle increases multiple dislocation loops are produced favorably over oxidation-induced stacking faults, which are dominantly produced when ground with finer abrasive particle. These defects are not related with the crystal growth process like Czochralski or directional solidification. During directional solidification process, twins and stacking faults are the two major defects observed in the bulk of the silicon crystal. On the other hand, slip dislocations produced by the thermal stress are not observed. Thus, not only in single crystalline silicon crystal but also in multi-crystalline silicon, extrinsic gettering process with programmed production of surface defects might be highly applicable to silicon wafers for purification.

• Korean Journal of Materials Research
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• v.7 no.1
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• pp.50-56
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• 1997

급냉응고법을 이용하여 고용한도 이상으로 Mn량을 첨가할 때 Mn량에 따른 인장특성의 변화와 시효특성을 조사하였다. 원심분무법으로 AI-4.7%Zn-2.5%Mg-0.2%Zr합금에 Mn량을 각기 달리 첨가한 급냉응고 분말을 제조 하였다. 이 분말을 냉간압축, 진공 탈가스처리를 한 후 15:1로 압출하여 봉상 시편을 만들었다. 분말의 미세조직은 $\alpha$-AI수지상과 수지상간 편석부로 이루어져 있으며 Mn첨가에 따라 조직의 변화는 관찰되지 않았다. 빠른 냉각속도로 인하여 2.0%Mn을 첨가한 경우에도 초정 Mn상을 발견할 수 없었다. 압출재의 미세조직은 아결정립으로 이루어져 있으며 약간의 제2상들이 관찰되었다. 대부분의 Mn 분산상은 압출후 용체화처리 과정에서 형성되었으며 시효경화량은 Mn양에 관계없이 일정하였다. 46$0^{\circ}C$에서 1시간 용체화처리하고 12$0^{\circ}C$에서 24시간 시효처리한 경우 최대의 시효경도값을 나타내었다. 인장강도는 Mn첨가량에 따라 증가 하였는데 이것은 Mn분산상의 밀도증가에 의한 것으로 확인되었다. 2.0%Mn을 첨가한 합금의 시효후 인장강도는 590MPa, 연산율은 4%를 보였다.