• 성인간호학회지
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• 제20권4호
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• pp.548-560
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• 2008

Purpose: This study was conducted to develop a simulation-based education course and to evaluate the results after the application for second year nursing students. Methods: This study was a non-equivalent control pre-post design. Based on the clinical situation scenarios about patients with COPD and MI, a total of two simulation-based learning modules was developed. Pretest and posttest was conducted to evaluate the difference in critical thinking disposition, problem solving, and clinical competence between two groups of 102 students for the experimental group, 2007 and 90 students for the control group, 2006. The experimental group conducted a clinical performance evaluation in the final test, on December 10, 2007. Results: In the experimental group, knowledge related to learning objectives was significantly increased and core intervention was performed almost exactly, but the same result was not observed in domains of analysis of laboratory test, and nursing education for patients. Self-evaluated clinical competence and problem solving level were significantly more improved in the experimental group than control group, but critical thinking disposition level wasn't. Conclusion: In conclusion, a simulation-based education course needs to utilize self-directed learning module like computer-based learning through web contents and MicroSim and video productions for improving nursing students' critical thinking.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제33권6호
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• pp.467-477
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• 2011

Purpose: The objective of this study was to examine the affected period and the amount of bone formation during osteogenesis of intramembranous bone using low-intensity pulsed ultrasound (LPUS) $in$ $vivo$. Methods: Xeno-bone (Bio-oss) and autogenous bone were grafted bilaterally into mini-pig mandibles. The left mandible served as the control and the other mandible was treated with 3 MHz, 160 mW (output, 0.8 mW) ultrasound stimulation for 7 days 15 minutes per day. The mini-pigs were sacrificed at 1, 2, 4, and 8 weeks, and micro computed tomography (${\mu}CT$), a microscopic examination, and a statistical analysis were performed on the specimens. Results: Based on a computerized image analysis of the ${\mu}CT$ scans, the experimental group had an average 150% more new bone formation than that in the control group. The effect of LPUS continued during the post operative 2 weeks. The histomorphological microscopic examination showed similar results. Conclusion: Our results suggest the LPUS had an effect on early intramembranous bone formation in vivo.

• BMB Reports
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• 제47권1호
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• pp.39-44
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• 2014

Increasing data shows miR-29a is a key regulator of oncogenic processes. It is significantly down-regulated in some kind of human tumors and possibly functionally linked to cellular proliferation, survival and migration. However, the mechanism remains unclear. In this study, we report miR-29a is significantly under-expressed in gastric cancer compared to the healthy donor. The microvessel density is negatively related to miR-29a expression in gastric cancer tissues. The ectopic expression of miR-29a significantly inhibits proliferation and invasion of gastric cancer cells. Furthermore, western blot combined with the luciferase reporter assays demonstrate that vascular endothelial growth factor A (VEGF-A) is direct target of miR-29a. This is the first time miR-29a was found to suppress the tumor microvessel density in gastric cancer by targeting VEGF-A. Taken together, these results suggest that miR-29a is a tumor suppressor in gastric cancer. Restoration of miR-29a in gastric cancer may be a promising therapeutic approach.

• 대한기계학회논문집
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• 제8권2호
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• pp.97-103
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• 1984

본 연구에서는 이에 주목하고 잔존하는 잔유응력을 제거한 상태에서 PWHT가 용접 HAZ조직의 파괴인성에 어떠한 영향을 미치고 있느가와 잔유응력이 잔존된 상태에 서의 PWHT 유대시간과 가열속도가 파괴인성에 어떠한 영향을 미치는가를 알아보기 위 하여 공시재에 무응력과 일정응력을 가한 상태에서 유대시간과 가열속도를 변화시켜가 며 PWHT를 실족한 후 소성굽힘에 의한 COD파괴인성 시험 등을 통하여 PWHT의 영향을 검토하였다.

• Molecular & Cellular Toxicology
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• 제5권1호
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• pp.23-31
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• 2009

To compare the effects of nanometer-sized silver ions and support materials (nano-silver coating material, NM-silver) and silver ions, we exposed zebrafish embryos to both types of nano-silver ions and compared the acute responses during embryogenesis. The amount of silver in the NM-silver (17.16%) was greater than that in the silver ion (4.56%). Both of these materials have different atomic compositions. The silver ion-exposed groups (10 and 20 ppt) showed lower survival rates than the NM-silver-exposed groups (10 and 20 ppt). NM-silver penetrated the skin and blood tube of zebrafish larvae as aggregated particles, whereas, silver ions penetrated the organelles, nucleus and yolk in a spread-out pattern. Micro-array analysis of RNA from zebrafish larvae (72 hours post-fertilization) that were treated with either NM-silver or silver ions, showed alteration in expression of the BMP, activin, TGF-$\beta$, and $GSK3{\beta}$ genes pathway. Additionally, $GSK3{\beta}$ gene pathway for apoptosis that was related with left-right asymmetry. Gene expression changes in the NM-silver or silver ions-treated zebrafish embryo led to phenotypic changes in the hatched larvae, reflecting increased apoptosis and incomplete formation of an axis.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.370-373
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• 2003

As the integrated circuit device shrinks to the smaller dimension, the chemical mechanical polishing (CMP) process was required for the global planarization of inter-metal dielectric(IMD) layer with free-defect. However, as the IMD layer gets thinner, micro-scratches are becoming as major defects. Chemical-Mechanical Planarization(CMP) of conductors is a key process in Damascene patterning of advanced interconnect structure. The effect of alternative commerical slurries pads, and post-CMP cleaning alternatives are discuess, with removal rate, scratch dentisty, surface roughness, dishing, erosion and particulate density used as performance metrics. Electroplated copper depostion is a mature process from a historical point of view, but a very young process from a CMP persperspective. While copper electrodepostion has been used and stuidied for dacades, its application to Cu damascene wafer processing is only now ganing complete accptance in the semiconductor industry. The polishing mechanism of Cu CMP process has been reported as the repeated process of passive layer formation by oxidizer and abrasion action by slurry abrasives. however it is important to understand the effect of oxidizer on copper pasivation layer in order to obtain higher removal rate and non-uniformity during Cu-CMP process. In this paper, we investigated the effects of oxidizer on Cu-CMP process regarding the additional volume of oxidizer.

• 한국자기학회지
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• 제6권5호
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• pp.340-352
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• 1996

최근 급속도로 발전하고 있는 첨단산업의 배경에는 반도체를 중심으로 한 디지틀 전자기술(Electronics)이 자리잡고 있음은 주지의 사실이다. 이러한 전자 및 정보기술 이후, 즉 포스트 일렉트로닉스(Post-electronics)시대를 겨냥한 새로운 돌파구로서 기대되고 있는 21세기 기술의 주도권을 잡을 기술이 어떤 기술이 될 것인가는 매우 흥미로운 질문이다. 현재 시점에서 볼 때 반도체를 매개로 한 20세기 정보전자혁명을 대신할 새로운 기술혁명으로 대두하고 있는것이 마이크로혁명이며, 이 마이크로혁명을 주도할 기술로서 세계적인 주목을 끌고 있는 기술중의 하나가 초소형 미소기계, 즉 마이크로머신(Micromachine)이다. 현재 '반도체를 능가할 수 있는 차세대 메카트로닉스(Mechatronics)혁명'이라 평가되고 있는 마이크로머신 기술은 과거 꿈으로나 가능하던 공상과학의 세계를 현실로 만들어 주는 경이로운 기술이며, 나아가 분자기술을 응용한 생체로봇, 생체컴퓨터 등 이른바 나노기술(Nano-technology)의 신세계로 향하는 입구라 할 수 있다. 이기술은 기계공학, 전자기술은 물론 물리학, 생물학, 화학, 재료공학 등 광범위한 분야의 기술이 총망라되어야 개발이 가능하며, 그 실현을 위해서는 매크로 한 세계와는 판이하게 다른 물리현상 등 마이크로한 세계의 특수성을 이해해야 함은 물론 에너지공급, 재료, 데이타통신, 구조조립 등 많은 기술적 난제를 극복해야 한다. 마이크로머신기술은 현재 일부 전문가를 제외하고는 일반은 물론 자기학분야의 연구자들에게도 별로 익숙하지 않은 분야이다. 그러나 이 기술의 미래 영향력이나 가능성, 필요성을 고려할 때 이제는 자기분야 연구자들도 이 분야에 관심을 가져야 할 것으로 생각하여 연구자들도 이 분야에 관심을 가져햐 할 것으로 생각하여 본고에서는 먼저 최근 마이크로머신의 기술동향을 개괄적으로 소개하고, 다음으로 마이크로머신에 사용되는 주요 재료들과 자성재료가 주도적인 기능을 하는 자기마이크로머신(Magnetic Micro-machine)에 사용되는 자성재료들에 관해 소개하고자 한다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1995년도 가을 학술발표회 논문집
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• pp.185-193
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• 1995

The softening behaviors of concrete have been the object of numerous experimental and numerical studies, because the load carrying capacity of cracked concrete structure is not zero. Numerical studies are devoted to the investigation of three-dimensional softening behaviors of concrete on the basis of a viscoplastic theory, which may be able to represent the effects of plasticity and also of rheology. In order to properly describe material behaviors corresponding to different stress levels, two surfaces in stress space are adopted; one is a yield surface, and the other is a failure or bounding surface. When a stress path reaches the failure surface, it is considered that the softening behaviors are initiated as micro-cracks coalesce and are simulated by assuming that the actual strain increments in the post-peak region are less than the equivalent viscoplastic strain increment. The experimental studies and the finite element analyses have been carried out under the displacement control. Numerically simulated results indicate that the model is able to predict the essential characteristics of concrete behaviors such as the non-linearity, stiffness degradation, different behaviors in tension and compression, and specially dilatation under uniaxial compression.

• Advances in concrete construction
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• 제4권2호
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• pp.89-105
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• 2016

The post - fire investigation is conducted on a fire-affected reinforced concrete shear wall building to ascertain the level of its strength degradation due to the fire incident. Fire incident took place in a three-storey building made of reinforced concrete shear wall and roof with operating floors made of steel beams and chequered plates. The usage of the building is to handle explosives. Elevated temperature during the fire is estimated to be $350^{\circ}C$ based on visual inspection. Destructive (core extraction) and non-destructive (rebound hammer and ultrasonic pulse velocity) tests are conducted to evaluate the concrete strength. X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) are used for analyzing micro structural changes of the concrete due to fire. Tests are conducted for concrete walls and roof slab on both burnt and unburnt locations. The analysis of test results reveals no significant degradation of the building after the fire which signifies that the structure can be used with full expectancy of performance for the remaining service life. This document can be used as a reference for future forensic investigations of similar fire affected concrete structures.

• Journal of Magnetics
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• 제12권3호
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• pp.129-132
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• 2007

Bismuth-substituted yttrium iron garnet (Bi:YIG, $Bi_{0.5}Y_{2.5}Fe_5O_{12}$) films were deposited with aerosol deposition method and their magnetic and optical properties were investigated as a function of annealing temperature. Since the ceramic films deposited with aerosol deposition method have not a perfect crystal structure due to non-uniform internal stress occurred by mechanical collision during their deposition, the post annealing could be a key process to release its internal stress and to improve its micro structure for optimizing the magnetic and magneto-optic properties of films. The crystallinity of Bi: YIG film was improved with increase of annealing temperature, and the saturation magnetization increased up to 87 emu/cc at $800^{\circ}C$. The Faraday rotation increased up to $1.4deg/{\mu}m$ by annealing at $700^{\circ}C$ around the wavelength of $0.5{\mu}m$. The optical transmittance of the Bi:YIG film was also improved in visible region.