• 전기화학회지
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• 제5권2호
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• pp.57-61
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• 2002

본 연구에서는 염화암모늄을 함유한 전해질에서 CoP 자성합금 박막을 전기도금 방식으로 제조하고 염화암모늄의 첨가량이 다른 용액에서의 CV 등 전기화학적인 분석을 통해 핵생성과 결정화(electrocrystallization)에 미치는 영향을 고찰하여 자기적 성질과의 상호관계를 밝히고자 하였다. 용액 중에 첨가된 염화암모늄은 첨가량이 많을수록 분극도를 감소시키고, charge transfer에 의해 electrocrystallization과정을 속도론적으로 제어함으로써 결정립의 크기가 커지고 orientation factor가 증가된다. 이러한 구조적, 결정학적 변화가 CoP 도금층의 자기적 성질을 변화시킴을 관찰하였다.

• 열처리공학회지
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• 제17권5호
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• pp.299-304
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• 2004

Influence of Ca addition on microstructure and room temperature mechanical properties has been studied for AZ31(Mg-3%Al-1%Zn-0.2%Mn)-(0~0.5)%Ca wrought alloys, based on experimental results from metallography, X-ray diffractometry and mechanical tests. Yield strength, ultimate tensile strength and hardness of the alloys increased remarkably with increasing Ca content, whereas elongation was deteriorated continuously. Microstructural examination revealed that Ca addition efficiently refined grains of ${\alpha}$(Mg) phase and that some of the Ca dissolved in ${\beta}(Mg_{17}Al_{12})$ precipitates. The former and the latter facts are thought to be responsible for improved strength and loss of ductility of the AZ31+Ca wrought alloys, respectively.

• Journal of the Korean Wood Science and Technology
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• 제12권4호
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• pp.36-46
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• 1984

한국식목질과 포틀랜드 시멘트(Type I)로 건축재개발가능성을 구명하기 위하여 소나무, 리기다 소나무, 잣나무, 일본잎갈나무, 현사시나무 목질과 왕겨 및 볏짚과 포틀랜드 시멘트 그리고 물과 혼합하여 24시간동알 수화열을 측정하고 수화억제지수를 산출한 바 리기다 소나무와 소나무가 한정된 조건하에서 목질-시멘트 복합체에 적절한 수종이며, 열수추출 수행하면 경화억제지수가 개선되어 왕겨, 잣나무, 일본잎갈나무는 한정된 조건하에서 적절한 수종이고 열수추출과 경화촉진제와 염화칼슘이나 염화마그네슘을 경울하면 현사시나무 일본 잎 갈나무도 리기다 소나무와 아울러 우수한 수종으로 판명되었다.

• 한국식품조리과학회지
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• 제23권1호통권97호
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• pp.83-89
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• 2007

This study was carried out to investigate the quality characteristics of sponge cake with mesangi(Capsosiphon fulvescens) powder added to give a control 0(control), 2, 4, 6 and 8% by weight per wheat flour. The crude protein was 33.37% for mesangi on a dry basis. Batter specific gravity, viscosity and baking loss increased with increasing mesangi powder content, whereas the specific loaf volume tended to decrease. Values of L and B decreased with increasing mesangi powder content while a value was minimized for the 4% mesangi powder. Hardness, cohesiveness, springiness, gumminess, and brittleness of sponge cakes with added mesangi powder content. The sensory tests indicated that aircell uniformity, firmness, sweetness and overall preference were not affected by the addition of 2 and 4% mesangi powder compared to control. Therefore, the addition of 4% mesangi powder to sponge cake was suggested as bing suitable to improve the quality.

• 한국농공학회논문집
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• 제55권3호
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• pp.113-121
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• 2013

Recently, it has been studied for the application of nano-materials in the concrete. Applied a small amount of nano-materials can achieve the goal of high strength, high performance and high durability. The small addition of nano clay improves strength, thermal stability, and durability of concrete because of the excellent dispersion. The present study has investigated the effectiveness, when varying with the contents of nano clay, influencing the pull-out behavior of macro synthetic fibers in nano materials cement mortar. Pullout tests conducted in accordance with the Japan Concrete Institute (JCI) SF-8 standard for fiber-reinforced concrete test methods were used to evaluate the pullout performance of the different nano clay. Nano clay was added to the 0, 1, 2, 3, 4 and 5 % of cement weight. The experimental results demonstrated that the addition of nano clay led to improve the pull-out properties as of the load-displacement curve in the precracked and debonded zone. Also, the compressive strength, flexural strength and pullout performance and of Mix No. 1 and No. 2 increased up to the point when nano clay used increased by 2 and 3 % contents, respectively, but decreased when the exceeded 3 and 4 %, respectively. It was proved by verifying increase of the scratching phenomenon in macro synthetic fiber surface through the microstructure analysis on the surface of macro synthetic fiber.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.993-998
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• 2009

This study was conducted to propose the model that is able to predict long-term settlement of sands containing carbonates. We can observe that in addition to the initial elastic compression, a considerable additional compression occurs with long-term period in some sands. The compressibility of sands is significantly dependent on particle characteristics. Some sands have many pores and particularly has an angular shape. To predict of long-term settlement of these sands which contain carbonates, first of all a variety of tests which are to assess chemical, physical and compression characteristics of these sands were conducted. Second, in order to know settlement with time, the time parameter was determined by analyzing the measured data obtained from $\bigcirc\bigcirc$ area. The measured settlement of this area shows that in addition to the initial elastic compression, a considerable additional compression occurring with time. It was caused by the crushing, shattering, and rearrangement of particles, which were real phenomena in sandy soils under loading condition. Based on this case study, we proposed that a simple method is able to predict settlement with time of sandy soil containing carbonates.

• Nuclear Engineering and Technology
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• 제45권1호
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• pp.67-72
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• 2013

Stress corrosion cracking (SCC) behaviors of Alloy 690 were studied in lead-containing aqueous alkaline solutions using the slow strain rate tension (SSRT) tests in 0.1M and 2.5M NaOH with and without PbO at $315^{\circ}C$. The side and fracture surfaces of the alloy were then examined using scanning electron microscopy after the SSRT test. Microstructure and composition of the surface oxide layer were analyzed by using a field emission transmission electron microscopy, equipped with an energy dispersive X-ray spectroscopy. Even though Alloy 690 was almost immune to SCC in 0.1M NaOH solution, irrespective of PbO addition, the SCC resistance of Alloy 690 decreased in a 2.5M NaOH solution and further decreased by the addition of PbO. Based on thermodynamic stability and solubility of oxide, high Cr of 30wt% in the Alloy 690 is favorable to SCC in mild alkaline and acidic solutions whereas the SCC resistance of high Cr Alloy 690 is weakened drastically in the strong alkaline solution where the oxide is not stable any longer and solubility is too high to form a passive oxide locally.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권5호
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• pp.509-524
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• 2017

Experiments and a numerical simulation were conducted to investigate the deformation and impact behavior of a corroded pipe, as corrosion, fatigue, and collision phenomena frequently occur in subsea pipelines. This study focuses on the deformation of the corrosion region and the variation of the geometry of the pipe under impact loading. The experiments for the impact behavior of the corroded pipe were performed using an impact test apparatus to validate the results of the simulation. In addition, during the simulation, material tests were performed, and the results were applied to the simulation. The ABAQUS explicit finite element analysis program was used to perform numerical simulations for the parametric study, as well as experiment scenarios, to investigate the effects of defects under impact loading. In addition, the modified ASME B31.8 code formula was proposed to define the damage range for the dented pipe.

• 동아시아식생활학회지
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• 제23권2호
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• pp.241-249
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• 2013

This study investigated yakpyun processing using jujube powder. The yakpyun was prepared with rice, jujube powder, makkolli, sugar, and salt. The yakpyun is made with various amounts (0, 2, 4, 6, 8%) of jujube powder. The effect of adding jujube powder on the quality characteristics of yakpyun were examined through SEM, mechanical tests, and sensory evaluation. The moisture contents of yakpyun were significantly reduced with increasing amounts of jujube powder. As the content of jujube powder increased, the lightness (L) decreased while redness (a) and yellowness (b) increased significantly (p<0.05). In texture profile analysis, hardness increased with increasing jujube powder content from initial production to three days of storage. In the structure of yakpyun examined through SEM, when more jujube powder was added, rougher surfaces were found more often (bigger holes between granules). The results of the sensory evaluation showed that the highest scores for overall acceptability were highest scores for yakpyun containing 6% level jujube powder. In conclusion, an addition of 6% jujube powder was optimal.

• Journal of Welding and Joining
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• 제15권6호
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• pp.57-65
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• 1997

A study was undertaken to determine the influence of welding variables such as shielding and plasma gases, torch standoff, travel speed and heat input, etc. on the quality of plasma arc welds in Zircaloy-4 sheet, 2mm thick. Effect of shielding gases and their flow rates on the mechanical properties of Zircaloy-4 welds by plasma arc welding were determined in terms of tensile, bardness and bend tests. The microstructure and fracture surface of Zircaloy-4 welds were investigated by optical and scanning electron microscopies. In addition, the causes of porosity and undercut in plasma arc welds of Zircaloy-4 were also investigated. Zircaloy-4 weld bead width and depth by helium shielding gas showed a wider and deeper than those by argon. It was found that Zircaloy-4 welds with shielding gas of helium did dxhibit a little smoother and uniform weld beads than those with shielding gas of argon. It was also found that the optimum gas flow rates for Zircaloy-4 welding were 0.45l/min for plasma gas with Ar and 4.5 - 6 l/min for shielding gas with He. In addition, there was no big difference in the microstructure and fracture surface of the weld metals made by either Ar shielding gas or He shielding gas.