• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.51.1-51.1
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• 2011

An electrospun Poly (lactice-co-glycolide acid) (PLGA) and Gelatin nanofiber tube was fabricated for potential intestinal stent application. Mechanical properties of tube were evaluated by tensile strength and burst strength tests. Physical and chemical properties were evaluated by contact angle measurement, swelling rates and porosity measurements. Biodegradability was investigated by immersion in simulated body fluid (SBF). Biocompatibility was investigated in vitro by cytotoxicity and proliferation studies by MTT assay, confocal microscopy and western blot using IEC-18 (Rat intestinal epithelial cell). After intestinal stent was implanted into rat bowel for periods from 7 to 10days, it was then analyzed using micro-computed tomography (Micro CT) and X-ray techniques. Futhermore, histological analysis was performed by hematoxylin-eosin (H&E) stain.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.51.2-51.2
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• 2011

A novel electrospun nanofiber membrane was fabricated using combined poly (vinylphosphonic acid) (PVPA) and polyvinyl alcohol (PVA) intended for bone tissue engineering applications. PVPA is a proton-conducting polymer used as primer for bone implants and dental cements to prevent corrosion and brush abrasion. The phosphonate groups of PVPA have the ability to crosslink and attach itself to the hydroxyapatite surface facilitating faster integration of the biomaterial to the bone matrix. PVA was combined with PVPA to provide hydrophilicity, biocompatibility and improve its spinnability. To improve its mechanical strength, PVPA/PVA and neat PVA mixtures were combined to produce a multilayer scaffold. The physical and chemical properties of the of the fabricated matrix was investigated by SEM and TEM morphological analyses, tensile strength test, XRD, FT-IR spectra, swelling behavior and biodegradation rates, porosity and contact angle measurements. Biocompatibility was also examined in vitro by cytotoxicity and cell proliferation studies with MTT assay and cell adhesion behavior by SEM and confocal microscopy.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.52.1-52.1
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• 2011

In this work, the effect of the addition of bioactive glass in the biocompatibility and mechanical behavior of conventional TTCP/DCPA based bone cement were investigated. The cement was initially modified with chitosan and HPMC which cross-linked with citric acid to improved mechanical properties.The injectable bone substitutes were further modified by adding varying amounts of bioactive glass (0%, 10%, 20% and 30%) and its effects on the biocompatibility of the material were studied. Afterbio-glass powders were mixed with the optimized composition for HPMC and citric acid content,the IBS was incubated at $37^{\circ}C$ at different time intervals and showed progressive formation of HAp with increasing time. Mechanical properties like Vickers hardness and compressive strength were found to increase with the increasing amount of bioactive glass addition and that setting time was shortened. The fabricated IBS morphologies were further characterized using SEM. MTT assay was performed to check the cell cytotoxicity and cell proliferation for 1, 3 and 5 days. Cell morphology, adhesion and proliferation behavior of cell in the IBS by culturing MG-63 cells on the IBS for 20, 60 and 90 mins and 1, 3 and 5 days was also investigated. All the results showed increasing biocompatibility as the bioglass content increased. MTT results found the materials to be cytocompatible and SEM images showed that cells attached and proliferated successfully.

• Journal of the Korean Wood Science and Technology
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• 제44권2호
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• pp.274-282
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• 2016

This aims of this study were to investigate the relationship between non-destructive evaluation (NDE) and actual bending properties of particleboard, and to predict the bending properties of three-layer particleboard. Three kinds of raw materials, i.e. Hinoki (Chamaecyparis obtusa Endl.) strand, knife-milled Douglas-fir (Pseudotsuga manziesii (Mirb) Franco), and hammer-milled matoa (Pometia spp.) obtained from wooden industry, were utilized as furnish for experimental panel with methylene diphenyl diisocyanate (MDI) resin as binder. The NDE test was conducted by hit sounds using an FFT analyzer according to the spectrum peak of wave frequency, while the static bending test was conducted according to JIS A-5908. The results reveal that the dynamic Young's modulus as an NDE test has a potential for being used to predict the elastic bending of particleboards by a specific equation for adjusting its proper values. The values of NDE and static test are significantly different with a deviation range at 3-20%. The bending stiffness of three-layer particleboards manufactured from different wood species is predictable by observing the bending stiffness of two elements based on the thickness of its layers. The predicted values of bending stiffness and static test are significantly different with a deviation range at 5-24%.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권2호
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• pp.155-159
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• 2020

Chronic maxillary atelectasis (CMA) is a progressive alteration in the volume of the maxillary sinuses that may result in facial asymmetry. CMA in asymptomatic patients is known as silent sinus syndrome (SSS) and is a rare entity, especially in pediatric patients. This study reports a case of SSS in a pediatric patient who received an early diagnosis through cone-beam computed tomography (CBCT). An asymptomatic 12-year-old female patient in orthodontic treatment presented with opacification of the left maxillary sinus on a panoramic radiograph. Clinically, the patient had discrete hypoglobus and enophthalmos. CBCT and nasal video-endoscopy revealed ostiomeatal obstruction with bone deformity, leading to diagnosis of SSS. Endonasal endoscopic maxillary sinusotomy was performed. Two years later, the patient remained asymptomatic, and a second CBCT exam confirmed a stable condition. This case highlights the role of optimal radiographic interpretation for early diagnosis of maxillofacial alterations in pediatric patients.

• International Journal of Quality Innovation
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• 제6권3호
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• pp.132-152
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• 2005

Today's society requires companies to act more and more effectively for the general good, by respecting human rights and the environment. Innovative and enlightened companies try to meet this need through the adoption of several initiatives. Accordingly, the International Standard Organisation is now working on attempts to unify these initiatives and to formulate an internationally recognised standard, providing guidance to companies on social responsibility. Currently the SA8000 international standard is the most often used tool-based on Corporate Social Responsibility (CSR) philosophy - which guarantees the respect of fundamental workers' rights. Since 2003, Italy holds the world record for its number of SA8000 certified companies. This paper discusses the findings of a two-stage survey of the Italian SA8000 certified companies carried out over the last two years. The focus of the survey is on both reasons and effects of the implementation of SA8000 standard. In the first stage the rate of response was very high while in the second stage it was satisfactory. The results provide a clear picture of the companies and their degree of achievement and awareness of the fundamental principles of human resource management. A section of the survey deals with some issues related to the Public Sector.

• Advances in aircraft and spacecraft science
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• 제2권4호
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• pp.403-425
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• 2015

This work is focused on the definition and the analysis of both complete and incomplete similitudes for the dynamic responses of thin shells. Previous numerical and experimental investigations on both structural and structural-acoustic systems motivated this further analysis, mainly centred on the incomplete (distorted) similitudes. These similitudes and the associated scaling laws are defined by using the classical modal approach (CMA) and by invoking also the Energy Distribution Approach (EDA) in order to take into account both the cinematic and energetic items. The whole procedure is named SAMSARA: Similitude and Asymptotic Models for Structural-Acoustic Research and Applications. A brief summary of the procedure is herein given and the attention is paid to the analytical models of thin stiffened and unstiffened cylindrical shells. By using the well-known smeared model, the stiffened cylinder equations are used as general framework to analyse the possibility to define exact (replicas) or distorted similitudes (avatars). Despite the extreme simplicity of the proposed models, the results are really encouraging. The final aim is to define equivalent models to be used in laboratory measurements.

• Advances in aircraft and spacecraft science
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• 제4권4호
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• pp.449-465
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• 2017

The aim of the present work is to present a computational study of the non-linear aero-elastic behavior of a multi-layered Thermal Protection System (TPS). The severity of atmospheric re-entry conditions is due to the combination of high temperatures, high pressures and high velocities, and thus the aero-elastic behavior of flexible structures can be difficult to assess. In order to validate the specific computational model and the overall strategy for structural and aerodynamics analyses of flexible structures, the simplified TPS sample tested in the 8' High Temperature Tunnel (HTT) at NASA LaRC has been selected as a baseline for the validation of the present work. The von $K{\acute{a}}rm{\acute{a}}n^{\prime}s$ three dimensional large deflection theory for the structure and a hybrid Raleigh-Ritz-Galerkin approach, combined with the first order Piston Theory to describe the aerodynamic flow, have been used to derive the equations of motion. The paper shows that a good description of the physical behavior of the fabric is possible with the proposed approach. The model is further applied to investigate structural and aero-elastic influence of the number of the layers and the stitching pattern.

• 한국정보과학회 언어공학연구회:학술대회논문집(한글 및 한국어 정보처리)
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• 한국정보과학회언어공학연구회 2001년도 제13회 한글 및 한국어 정보처리 학술대회
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• pp.267-272
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• 2001

구(phrase) 단위 또는 문장(sentence) 단위의 연어(collocation) 정보는 자연언어 처리를 위한 단일어 또는 이중어 데이터베이스를 구축할 수 있는 중요한 기초 자료가 될 뿐 아니라, 외국어 학습에서도 어휘 단계를 넘어선 학습 자료를 제공할 수 있다. 불어는 굴절 언어(inflectional language)로서 기본형 대 굴절형의 비율이 약 1:9 정도로 비교적 굴절 비율이 높은 언어다. 또한 불어 표제어 중 95% 이상을 차지하는 불어의 동사, 명사, 형용사 중 상당한 비율이 암기해야 할 목록(list)이라는 특성을 갖기 때문에 검색과 학습에 있어 오류가 지속적으로 일어나는 부분이다. 표제어의 검색의 경우 불어 굴절 현상을 지원하는 전자 사전이 개발되어 있지만 아직까지 연어 정보에서 굴절형을 지원할 수 사전 또는 데이터베이스는 개발되어 있지 않다. 본 연구의 목적은 전자 사전과 형태소 분석기를 이용하여 굴절형 처리를 지원할 수 있는 불-한 연어 데이터베이스를 구축하는데 있다. 이를 위해 부산대학교 언어정보 연구실에서 개발한 불어 형태소 분석기 Infection와 불-한 전자 사전 Franco를 사용하였으며, 지금까지 구축된 불-한 연어 정보는 94,965 개이다. 본 고에서는 두 정보를 이용하여 불어 굴절형 정보를 분석 및 생성하는 방식 및 불-한 연어 데이터베이스 구조를 살펴 본다.

• 천문학회지
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• 제40권4호
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• pp.171-177
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• 2007

In external galaxies, the velocity dispersion of the atomic hydrogen gas shows a remarkably flat distribution with the galactocentric radius. This has been a long-standing puzzle because if the gas velocity dispersion is due to turbulence caused by supernova explosions, it should decline with radius. After a discussion on the role of spiral arms and ram pressure in driving interstellar turbulence in the outer parts of galactic disks, we argue that the constant bombardment by tiny high-velocity halo clouds can be a significant source of random motions in the outer disk gas. Recent observations of the flaring of H I in the Galaxy are difficult to explain if the dark halo is nearly spherical as the survival of the streams of tidal debris of Sagittarius dwarf spheroidal galaxy suggests. The radial enhancement of the gas velocity dispersion (at R > 25 kpc) due to accretion of cloudy gas might naturally explain the observed flaring in the Milky Way. Other motivations and implications of this scenario have been highlighted.