• KSBB Journal
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• v.18 no.5
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• pp.412-417
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• 2003

We first investigated basic characteristics of reticulated polyurethane (PU) foams as microbial carriers. In general, the specific surface area of PU foams increases with respect to decreasing pore sizes. However, the number of microbes adhered on the unit surface of reticulated PU foams decreases with respect to decreasing pore sizes. Thus, as a result of totally considering all effects such as apparent density, hydrolysis rate, and adhesion, we can know that PU foams with 45 PPI is the most appropriate microbial carrier. In this study, we can also investigate the effect of various physico-chemical surface treatments on the adhesion of microbes on the surface of PU foams. We used a chitosan treatment, a PEI (Polyethylene Imine) treatment, a xanthane treatment and a plasma treatment. As a result of comparing all surface treatments, the plasma surface treatment was the best.

• Korean journal of applied entomology
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• v.32 no.1
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• pp.68-75
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• 1993

Morphometric investigations of the leg characters of both sexes of brachypterous Korean N. lugens biotypes were made. Simple and multivariate statistical analyses revealed that the three N. lugens biotypes differed from one another. The amount of variation and segregation between and among the three biotype populations were approximated by the scatter plot diagrams based on the computed discriminant scores. The variables of leg characters provided the most significant segregations of three biotype populations, thus, categorizing the three biotypes as distinct intraspecific populations of N. lugens.

• Composites Research
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• v.22 no.1
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• pp.15-21
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• 2009

In this paper, static compressive test and compression-compression fatigue test of carbon/epoxy composites which have different micro-structures were carried out with respect to the bias angle. In order to find out the effect of the micro-structure of the fabric composite on compressive characteristics the specimens made of UD carbon/epoxy composite comprising the same fiber and matrix system as the fabric composite were also prepared. The compressive strength and modulus were measured and these values were used to develop a semi-empirical formula for predicting compressive strength of the fabric composite with bias angles. The fatigue behavior of the fabric composite with respect to the bias angle variation was also investigated.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.190-201
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• 2004

The aim of this study was to evaluate the resistance to degradation and to compare the wear resistance characteristics of four esthetic restorative materials in an alkaline solution. The brands studied were Charmfil, Charmfil flow(composite resin), Compoglass F and PrimaFlow(compomer). The results were as follows: 1. The mass loss were not significantly different among the materials(p>0.05). 2. The sequence of the degree of degradation layer depth was in descending order by Compoglass F, PrimaFlow, Charmfil, and Charmfil flow. There were significant differences between Compoglass F and the others(p<0.05). 3. The sequence of the Si loss was in descending order by Charmfil flow, Charmfil, PrimaFlow, and Compoglass F. There were significant differences among these materials(p<0.05). 4. When observed with SEM, destruction of bonding between matrix and filler was observed and when observed with CLSM, the depth of degradation layer of specimen surface was observed. 5. The sequence of maximum wear depth was in descending order by Comfoglass, PrimaFlow Charmal, and Charmfil flow. There were significant differences among these materials(p<0.05). 6. The correlation coefficient between Si loss and degradation layer depth (r=0.602, p<0.05) Vicker's hardness number and maximum wear depth (r=0.501, p<0.05) were relatively high. These results indicate that wear and hydrolytic degradation may be considered to be evaluation factors of composite resins and compomers.

• Korean Journal of Environment and Ecology
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• v.24 no.2
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• pp.147-156
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• 2010

This study was conducted from April, 2002 to March 2006, using three urban streams(Gap Stream, Yudeung Stream and Daejeon Stream) in Daejeon Metropolitan City. 12,027 individual birds summed by the peak count in 126 species, 34 families, and 13 orders were observed from three stream sites. Dominant species were of Anas poecilorhyncha, Anas crecca, Columba livia, Passer montanus, and Egretta garzetta(in that order). The groups of birds were classified into six types. The most frequent group were the arbor birds(54 species), while the smallest group was the diving ducks(7 species). As for the number of individuals, the shrub bird group had 721 individuals while the dabbling ducks observed had 4,974 individuals. Regarding the distribution of birds appeareing in each stream, 14,885 individual numbers in 114 species were observed at Gap Stream, 6,642 individuals in 90 species at Yudeung Stream and 4,202 individuals in 69 species at Daejeon Stream. Various indices of the birds were analyzed with respects to the similarities between streams. Gap Stream had similar characteristics to Yudeung Stream, and the latter was similar to Daejeon Stream. However, Gap Stream and Daejeon Stream showed different characteristics. The dominance index of each section was calculated using ten dominant bird species top-down. Subsequently, the birds and their preferred environment were analyzed. The results showed that shrub birds and arbor birds preferred the upper stream of every stream, while herons and dabbling ducks inhabited the midstream. Dabbling ducks and some diving ducks appeared downstream.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.422.2-422.2
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• 2014

가스장 이온원(GFIS: Gas Field Ionization Source)은 전자현미경보다 분해능이 향상된 이온현미경의 광원으로 사용하기 위하여 연구되고 있고, 큰 각전류 밀도, 작은 크기의 가상 이온원 그리고 좁은 에너지 퍼짐을 특징으로 한다. 여러 가지 장점을 가지고 있는 GFIS을 개발하기 위해서는 GFIS에서 발생된 이온빔의 형상을 관찰 것이 매우 중요하며, 이러한 관찰을 위한 시스템에는 주로 마이크로 채널 플레이트 (MCP: Micro Channel Plate)가 사용된다. MCP는 채널내부에 입사한 입자의 에너지에 의해서 생성된 이차전자를 수 천 배에서 수 백 만 배 이상 증폭시켜 형광판에 조사하고 발광시키는 방법으로 작은 신호를 영상으로 관찰 할 수 있도록 한다. MCP의 큰 증폭비는 작은 크기의 신호를 큰 신호로 증폭하여 관찰하는데 용이하여, GFIS 방법으로 생성된 이온빔(이온빔 전류 값은 pA 수준)을 관찰하기에 적합하다. 그러나 MCP를 이용하여도 증폭된 이온빔의 세기가 매우 작기때문에 생성된 이온빔 형상을 정확하게 관찰하기 위해서는 MCP의 형광판을 촬영하는 카메라 노출시간을 길게하여 데이터 수집 시간을 늘려야 하는 문제가 있다. 본 발표에서는 이온빔 형상 관찰에 소요되는 시간을 단축하기 위하여 MCP의 잡음이 GFIS의 이온빔 이미지 관찰에 미치는 영향을 분석하고 이를 제거 방법을 소개한다. 본 연구에서는 GFIS 방출 이온빔의 이미지에 포함된 MCP 잡음 특성을 장(전계)이온현미경 (Field Ion Microscope)실험을 통하여 분석하였고, 디지털 이미지 처리 방법을 이용하여 방출 이온빔 이미지에서 MCP 잡음을 제거하여 방출 이온빔 이미지만 추출할 수 있었다. 본 연구에서 제안한 방법을 GFIS 방출 이온빔 관찰시스템에 적용함으로써 기존 방법에 비해 노출시간을 단축하여 방출 이온빔을 관찰 할 수 있었으며, 노이즈 제거 효과로 향상된 이온빔 형상을 얻을 수 있었다. 본 연구결과의 관찰시간 단축과 향상된 이온빔 형상 획득은 이온현미경 개발에 필수적인 단원자 이온빔을 보다 효율적으로 개발할 수 있으며 디지털 이미지 처리로 GFIS 이온빔 생성을 자동화하는데 응용할 수 있다. 더불어 기존방법에 비해 이미지 획득을 위한 MCP의 노출시간을 단축할 수 있으므로 실험장비 수명 단축 방지 및 관리에 큰 장점이 있다.

• Journal of Korean Orthopaedic Sports Medicine
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• v.11 no.2
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• pp.82-86
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• 2012

Purpose: The purpose of this study was retrospectively to evaluate the results of the modified Kidner procedure for symptomatic accessory navicular in athletes. Materials and Methods: Between July 1999 and December 2004, 26 feet in 22 patients with symptomatic accessory navicular who had underwent modified Kidner procedure were available for clinical follow-up, and 12 cases in 9 patients were available for clinical and radiological follow-up with a minimum follow-up of 5 years were included in this study. All those patients had symptomatic accessory navicular bone who underwent modified Kidner procedure. American Orthopaedic Foot and Ankle Society (AOFAS) midfoot score, Visual Analogue Scale (VAS), and satisfaction rate were investigated. Talo-first metatarsal (T-MT1) angle, talo-calcaneal (TC) angle, and calcaneal pitch (CP) angle were measured in standing lateral radiograms. Results: AOFAS score was improved from $40.8{\pm}7.5$ (32~57) preoperatively to $88.7{\pm}8.0$ (72~100) postoperatively, and the difference was significant (p<0.01). VAS was improved from $7.0{\pm}0.9$ (5~9) preoperatively to $1.8{\pm}0.8$ (1~4) postoperatively, and the difference was significant (p<0.01). At the lastest follow up, 11 feet were very satisfied, 11 feet satisfied, and 4 feet unsatisfied (a satisfaction rate 85.0%). No significant difference was observed for T-MT1 angle (p=0.67), TC angle (p=0.93), and CP angle (p=0.49). Conclusion: Modified Kidner procedure for the symptomatic accessory navicular showed satisfactory results and is appeared to be one of the useful treatments.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.337-347
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• 2011

The basic structure of the primary crowns usually resemble their succeeding permanent teeth. However, maxillary second primary molars resemble ipsilateral first permanent molars. Accordingly in this study, odontometric data of the two teeth was obtained, then analyzed to verify the morphological relationship and sex difference between the two teeth. Dental study casts were examined for their mesiodistal and buccolingual width of the crowns, diameter of each cusps, and intercuspal distances. Photographs of the crowns were taken to measure the angles between each cusp tip. The results are as follows : 1. In boys, PrI, PaI, DBC angle, and MBC angle did not show any statistically significant difference between the two teeth(p>0.05), and moderate level of correlations were observed. 2. In girls, crown index, DBC angle, and MBC angle of the two teeth did not show any statistically significant difference(p>0.05), and moderate level of correlations were recognized. 3. Measurements that did not show statistically significant difference between the two teeth in both boys and girls were DBC angle and MBC angle(p>0.05). In DLC angle, however, statistically significant difference was observed(p<0.01). 4. Most of the measurements showed sex differences, except DBC angle, which did not show any sex difference in both teeth(p>0.05).

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.48-54
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• 2007

컴퓨터 네트워크의 발달로 인터넷이 실생활이 되면서, 온라인에서 인스턴트 메신저를 이용한 커뮤니케이션 방식이 확대되고 있다. 이러한 메신저에서는 이모티콘 및 플래시콘 혹은 윙크 등 과 같은 다양한 방식을 통해 감정을 표현할 수 있도록 제안하고 있다. 하지만, 아직까지 온라인의 감정표현은 흥미위주이며, 오프라인의 다양한 감정표현에 비해서 제한적이다 따라서 오프라인에서의 다양한 사용자 감정표현을 온라인에서 표현해 줄 수 있는 새로운 형태의 감성 커뮤니케이션 방법이 필요하다. 본 연구에서는 온라인 인스턴트 메신저의 사용행태 이해를 통해서 사용자들의 요구사항을 파악하고 이를 통해 제안할 수 있는 커뮤니케이션 방법을 모색하고자 한다. 실생활에서 사용자의 감정표현 방법을 바탕으로 온라인 메신저에 적용하여 새로운 감성 커뮤니케이션 방법을 제안하는 연구로, 감정어휘와 표현방법의 사용자 조사를 통해 감정표현 방법에 대한 컨셉을 제안하였다. 우선 메신저 사용 행태와 요구사항 도출을 위한 사용자 FGI를 진행하였다. 사용자 FGI로 얻어진 사용자들의 메신저 사용행태를 통해, 텍스트와 모션을 활용하는 '텍스트콘'을 컨셉 아이디어로 도출하였다. 아이디어에 적용하기 위해 모션을 감정으로 인해 파생되는 행동과 체감각 요소로 구분하였다. 구체적인 표현방법 및 적용 요소를 추출하기 위한 방법으로 온라인 설문조사를 실시하였으며 감정어휘와 표현방법(행동, 체감각)을 추출하였다. 추출된 내용은 '사용자 참여 관찰' 기법을 활용하여, 사용어휘와 행동을 정리하고 구제화하여 그 결과를 '텍스트콘'에 적용하였다. 본 연구는 사용자들이 메신저를 이용한 감정표현에 있어 텍스트를 선호하고 텍스트에 대한 요구사형에 있음을 확인하였으며, 감정표현 컨셉 아이디어 '텍스트콘'을 도출하였다. '사용자 참여 관찰' 기법을 활용하여 기존의 이모티콘으로 대표되는 그래픽 아이콘 중심의 사용자 감정표현 방법을 보조해줄 수 있는 방법으로 실생활에서 사용자가 표현하고 받아들이는 신체언와 행동을 적용하였다는 것에 그 의의가 있다. 또한, 감정에 의한 생리적 반응 요소를 외적인 반응과 내적인 반응으로 구분하여, '체감각'이라고 하는 내적반응을 중심표현방법으로 삼아, 기존과는 다른 시각으로 접근할 수 있었다.

• Elastomers and Composites
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• v.45 no.1
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• pp.2-6
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• 2010

The sizing treatments of PAN-based carbon fiber surfaces were carried out in order to improve the interfacial adhesion in the carbon fibers/nylon6 composite system. The parameter to characterize the wetting performance and surface free energy of the sized fibers were determined by a contact angle method. The mechanical interfacial properties of the composites were investigated using critical stress intensity factor ($K_{IC}$). The cross-section morphologies of sized CFs/nylon6composites were observed by SEM. As the experimental results, it was observed that silane-based sizing treated carbon fibers showed higher surface free energies than other sizing treatments. In particular, the KIC of the sizing-treated carbon fibers reinforced composites showed higher values than those of untreated carbon fibers-reinforced composites. This result indicated that the increase in the surface free energy of the fibers leads to the improvement of the mechanical interfacial properties of carbon fibers/nylon6 composites.