• 대한소아치과학회지
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• 제35권3호
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• pp.418-426
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• 2008

본 연구에서는 구강 환경과 유사한 조건에서 불소방출성을 보이는 콤포짓트 레진계 수복재의 내구성과 불소방출성을 조사하기 위해 4 종의 콤포머와 1 종의 불소방출성 콤포짓트 레진을 실험재료로 선택하고 $5^{\circ}C$와 $55^{\circ}C$ 수중에서의 열순환 처리 후의 인장강도, 열순환 처리 후 칫솔에 대한 작용력 1.5N으로 100,000회 칫솔질을 시행하였을 때의 표면조도 및 불소치약 칫솔질 후 $37^{\circ}C$ 수중에서의 불소이온 용출 양상을 조사한 결과 다음과 같은 결론을 얻었다. 1. 인장강도는 TC($Tetric^{(R)}$ Ceram)군에서 32.3 MPa, CF(Compoglass F)군에서 16.8 MPa이고, TC군과 DF($Dyract^{(R)}$ flow)군 및 CF군에서 유의한 차이를 보였다(P<0.05). 2. 칫솔질 마모시험 후의 표면조도 Ra는 TC군에서 0.287, FT(F2000)군에서 1.516이고, FT군과 나머지 시험군 사이에 유의한 차이를 보였다(P<0.05). 3. 칫솔질 마모시험 후의 표면에서는 필러의 돌출과 탈락 양상이 관찰되었다. 4. 불소치약 Perio Alpine Herb로 칫솔질 한 후 콤포머는 초기에 높은 용출을 보인 후 시간이 경과하면서 용출량이 감소하는 양상을 보였지만, 불소방출성 콤포짓트 레진의 TC군에서는 초기단계부터 낮으면서도 지속적인 용출을 보였다. 5. 불소치약 Perio Alpine Herb로 칫솔질 한 후 1시간이 경과하였을 때의 불소이온 용출량은 CF군에서 $2.064{\mu}g/cm^2$, TC 군에서 $0.1119{\mu}g/cm^2$이고, CF군의 용출량이 나머지 시험군에 비해 유의하게 높은 값을 보였다(P<0.05).

• 한국산림과학회지
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• 제84권2호
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• pp.151-165
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• 1995

한국산(韓國産) 옻나무과(科) 6식종(植種)과 외래(外來) 2식종(植種)을 대상(對象)으로 잎의 형태학적(形態學的) 형질조사(形質調査), 엽맥상(葉脈相)의 특징(特徵) 조사(調査), 주사전자현미경(走査電子顯微鏡)을 이용하여 기공(氣孔)과 잎의 epidermal 세포(細胞)의 구조특성(構造特性)을 조사(調査)하였다. 연구결과(硏究結果)에 대한 분류군간(分類群間)의 각 형질(形質)을 비교(比較)하였으며, 결과(結果)를 요약(要約)하면 다음과 같다. 1. 잎의 형태적(形態的) 형질(形質)에 의(依)한 유집분석(類集分析) 결과(結果) 산검양옻나무, 미국털옻나무, 검양옻나무 유집군(類集群)과 개옻나무, 붉나무, 옻나무 유집군(類集群) 및 덩굴옻나무, 미국덩굴옻나무 유집군(類集群)으로 분류(分類)되었다. 엽형질(葉形質)에 대(對)한 주성분(主成分) 분석(分析)에서는 Eigenvalue 1.0이상(以上)인 제(第)3 주성분(主成分)까지의 누적기여율(累積寄與率)은 82.6%로서 설명력(說明力)이 높았다. 2. 엽맥(葉脈)의 형태(形態)와 2차맥(次脈)의 분지각(分枝角)에 따라 망상(網狀), 곡주맥(曲走脈)과 방사상(放射狀) 곡주맥(曲走脈)으로 구분(區分)되었으며, 2차맥(次脈)의 발달(發達) 정도(程度)에 따라 종(種)의 식별(識別)이 가능(可能)하였으며, 종검색표(種檢索表)를 작성(作成)하였다. 3. 기공(氣孔) 형태(形態)는 paracytic과 anomocytic형(形)으로 구별(區別)되었으며, 기공지수(氣孔指數)에 따라 종간(種間)의 분류(分類)가 가능(可能)하였다. 또한 잎 표면세포(表面細胞)의 구조(構造)와 형태(形態)도 synclinal과 anticlinal cell wall pattern으로 구분(區分)되어 종간(種間)의 차이(差異)가 인정(認定)되었다.

• Asia pacific journal of information systems
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• 제18권2호
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• pp.41-72
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• 2008

The purpose of this study is the investigation of the effects of user participation, network effect, social influence, and usefulness on stickiness and continued use on Internet communities. In this research, stickiness refers to repeat visit and visit duration to an Internet community. Continued use means the willingness to continue to use an Internet community in the future. Internet community-based companies can earn money through selling the digital contents such as game, music, and avatar, advertizing on internet site, or offering an affiliate marketing. For such money making, stickiness and continued use of Internet users is much more important than the number of Internet users. We tried to answer following three questions. Fist, what is the effects of user participation on stickiness and continued use on Internet communities? Second, by what is user participation formed? Third, are network effect, social influence, and usefulness that was significant at prior research about technology acceptance model(TAM) still significant on internet communities? In this study, user participation, network effect, social influence, and usefulness are independent variables, stickiness is mediating variable, and continued use is dependent variable. Among independent variables, we are focused on user participation. User participation means that Internet user participates in the development of Internet community site (called mini-hompy or blog in Korea). User participation was studied from 1970 to 1997 at the research area of information system. But since 1997 when Internet started to spread to the public, user participation has hardly been studied. Given the importance of user participation at the success of Internet-based companies, it is very meaningful to study the research topic of user participation. To test the proposed model, we used a data set generated from the survey. The survey instrument was designed on the basis of a comprehensive literature review and interviews of experts, and was refined through several rounds of pretests, revisions, and pilot tests. The respondents of survey were the undergraduates and the graduate students who mainly used Internet communities. Data analysis was conducted using 217 respondents(response rate, 97.7 percent). We used structural equation modeling(SEM) implemented in partial least square(PLS). We chose PLS for two reason. First, our model has formative constructs. PLS uses components-based algorithm and can estimated formative constructs. Second, PLS is more appropriate when the research model is in an early stage of development. A review of the literature suggests that empirical tests of user participation is still sparse. The test of model was executed in the order of three research questions. First user participation had the direct effects on stickiness(${\beta}$=0.150, p<0.01) and continued use (${\beta}$=0.119, p<0.05). And user participation, as a partial mediation model, had a indirect effect on continued use mediated through stickiness (${\beta}$=0.007, p<0.05). Second, optional participation and prosuming participation significantly formed user participation. Optional participation, with a path magnitude as high as 0.986 (p<0.001), is a key determinant for the strength of user participation. Third, Network effect (${\beta}$=0.236, p<0.001). social influence (${\beta}$=0.135, p<0.05), and usefulness (${\beta}$=0.343, p<0.001) had directly significant impacts on stickiness. But network effect and social influence, as a full mediation model, had both indirectly significant impacts on continued use mediated through stickiness (${\beta}$=0.11, p<0.001, and ${\beta}$=0.063, p<0.05, respectively). Compared with this result, usefulness, as a partial mediation model, had a direct impact on continued use and a indirect impact on continued use mediated through stickiness. This study has three contributions. First this is the first empirical study showing that user participation is the significant driver of continued use. The researchers of information system have hardly studies user participation since late 1990s. And the researchers of marketing have studied a few lately. Second, this study enhanced the understanding of user participation. Up to recently, user participation has been studied from the bipolar viewpoint of participation v.s non-participation. Also, even the study on participation has been studied from the point of limited optional participation. But, this study proved the existence of prosuming participation to design and produce products or services, besides optional participation. And this study empirically proved that optional participation and prosuming participation were the key determinant for user participation. Third, our study compliments traditional studies of TAM. According prior literature about of TAM, the constructs of network effect, social influence, and usefulness had effects on the technology adoption. This study proved that these constructs still are significant on Internet communities.

• Asia pacific journal of information systems
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• 제19권1호
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• pp.147-165
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• 2009

Virtual community(VC) will increasingly be organized as commercial enterprises, with the objective of earning an attractive financial return by providing members with valuable resources and environment. For example, Cyworld.com in Korea uses several community services to enable customers of Cyworld to take control of their own value as potential purchasers of products and services. Although initial adoption is important for online network service success, it does not necessarily result in the desired managerial performance unless the initial usage is continuously related to the continuous usage and purchase. Particularly, the customer who receives relevant online services and is well equipped with online network services, will trust the online service provider and perceive less risk and experience more activities such as continuous usage and purchase. Thus, how to promote continued online service usage or, alternatively, how to prevent discontinuance is a critical issue for VC service providers to consider. By aggregating a wide range of information and online environments for customers and providing trust to its members, the service providers of virtual communities help to reduce the perceived risk of continuous usage and purchase. Drill down, online service managers realize that achieving strong and sustained customers who continuously use online service and purchase on it is crucial. Therefore, the research into this online service continuance will identify the relationship between the initial usage and the continuous usage and purchase. The research of continuous usage or post adoption has recently emerged as an important issue in the IS literature. Individuals' information systems(IS) continuous usage decisions are congruent with consumers' repeat purchase decisions. The TAM(Technology Acceptance Model) paradigm has been strongly confirmed across a wide range from product purchase on EC to online service usage contexts. The analysis of IS usage based on TAM has proven to be successful across almost online service contexts. However, most of previous studies have focused on only an area (i.e., VC or EC). Just little research has tried to analyze the relationship between VC and EC. The effect of some factors on user intention, captured through several theories such as TAM, has been demonstrated. Yet, few studies have explored the salient relationships of VC users' EC acceptance. To fill this gap between VC and EC research, this paper attempts to develop a research model that extends the TAM perspective in view of the additional contributions of trust in the service provider and trust in members on some factors that affect EC and VC adoption. In this extension, we applied the TAM-to-TAM(T2T) model, and analyzed the transfer effect of trust between these two TAMs. The research model was empirically tested on the context of a social network service. The model was to extend TAM with the trust concept for the virtual community environment from the perspective of tasks. By building an extended model of TAM and examining the relationships between trust and the existing variables of TAM, it is aimed to explain a user's continuous intention to use VC and purchase on EC. The unit of analysis in this paper is an individual user of a virtual community. The population of interest is the individual with the experiences in virtual community. The data for this paper was made available via a Web survey of VC users. In total, 281 cases were gathered for about one week, but there were some missing values in the sample and there were some inappropriate cases. Thus, only 248 cases were finally analyzed. We chose the structural equation analysis to test the hypotheses and it is better suited for explaining complex relationships than the other methods. In this test, AMOS was used to test the Structural Equation Model (SEM). Noticeable results have been found in the T2T model regarding the factors affecting the intention to use of virtual community and loyalty. Our result showed that trust transfer plays a key role in forming the two adoption beliefs. Overall, this study preliminarily confirms the salience of trust transfer in online service.

• Asia pacific journal of information systems
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• 제19권1호
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• pp.33-62
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• 2009

Internet computing is a disruptive IT innovation. Semantic Web can be considered as an IT innovation because the Semantic Web technology possesses the potential to reduce information overload and enable semantic integration, using capabilities such as semantics and machine-processability. How should organizations adopt the Semantic Web? What factors affect the adoption and diffusion of Semantic Web innovation? Most studies on adoption and diffusion of innovation use empirical analysis as a quantitative research methodology in the post-implementation stage. There is criticism that the positivist requiring theoretical rigor can sacrifice relevance to practice. Rapid advances in technology require studies relevant to practice. In particular, it is realistically impossible to conduct quantitative approach for factors affecting adoption of the Semantic Web because the Semantic Web is in its infancy. However, in an early stage of introduction of the Semantic Web, it is necessary to give a model and some guidelines and for adoption and diffusion of the technology innovation to practitioners and researchers. Thus, the purpose of this study is to present a model of adoption and diffusion of the Semantic Web and to offer propositions as guidelines for successful adoption through a qualitative research method including multiple case studies and in-depth interviews. The researcher conducted interviews with 15 people based on face-to face and 2 interviews by telephone and e-mail to collect data to saturate the categories. Nine interviews including 2 telephone interviews were from nine user organizations adopting the technology innovation and the others were from three supply organizations. Semi-structured interviews were used to collect data. The interviews were recorded on digital voice recorder memory and subsequently transcribed verbatim. 196 pages of transcripts were obtained from about 12 hours interviews. Triangulation of evidence was achieved by examining each organization website and various documents, such as brochures and white papers. The researcher read the transcripts several times and underlined core words, phrases, or sentences. Then, data analysis used the procedure of open coding, in which the researcher forms initial categories of information about the phenomenon being studied by segmenting information. QSR NVivo version 8.0 was used to categorize sentences including similar concepts. 47 categories derived from interview data were grouped into 21 categories from which six factors were named. Five factors affecting adoption of the Semantic Web were identified. The first factor is demand pull including requirements for improving search and integration services of the existing systems and for creating new services. Second, environmental conduciveness, reference models, uncertainty, technology maturity, potential business value, government sponsorship programs, promising prospects for technology demand, complexity and trialability affect the adoption of the Semantic Web from the perspective of technology push. Third, absorptive capacity is an important role of the adoption. Fourth, suppler's competence includes communication with and training for users, and absorptive capacity of supply organization. Fifth, over-expectance which results in the gap between user's expectation level and perceived benefits has a negative impact on the adoption of the Semantic Web. Finally, the factor including critical mass of ontology, budget. visible effects is identified as a determinant affecting routinization and infusion. The researcher suggested a model of adoption and diffusion of the Semantic Web, representing relationships between six factors and adoption/diffusion as dependent variables. Six propositions are derived from the adoption/diffusion model to offer some guidelines to practitioners and a research model to further studies. Proposition 1 : Demand pull has an influence on the adoption of the Semantic Web. Proposition 1-1 : The stronger the degree of requirements for improving existing services, the more successfully the Semantic Web is adopted. Proposition 1-2 : The stronger the degree of requirements for new services, the more successfully the Semantic Web is adopted. Proposition 2 : Technology push has an influence on the adoption of the Semantic Web. Proposition 2-1 : From the perceptive of user organizations, the technology push forces such as environmental conduciveness, reference models, potential business value, and government sponsorship programs have a positive impact on the adoption of the Semantic Web while uncertainty and lower technology maturity have a negative impact on its adoption. Proposition 2-2 : From the perceptive of suppliers, the technology push forces such as environmental conduciveness, reference models, potential business value, government sponsorship programs, and promising prospects for technology demand have a positive impact on the adoption of the Semantic Web while uncertainty, lower technology maturity, complexity and lower trialability have a negative impact on its adoption. Proposition 3 : The absorptive capacities such as organizational formal support systems, officer's or manager's competency analyzing technology characteristics, their passion or willingness, and top management support are positively associated with successful adoption of the Semantic Web innovation from the perceptive of user organizations. Proposition 4 : Supplier's competence has a positive impact on the absorptive capacities of user organizations and technology push forces. Proposition 5 : The greater the gap of expectation between users and suppliers, the later the Semantic Web is adopted. Proposition 6 : The post-adoption activities such as budget allocation, reaching critical mass, and sharing ontology to offer sustainable services are positively associated with successful routinization and infusion of the Semantic Web innovation from the perceptive of user organizations.

• Clinical and Experimental Reproductive Medicine
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• 제26권2호
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• pp.163-170
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• 1999

Objectives: The aims of this study are 1) to determine if GAST is a better indicator in predicting ovarian response to COH compared with patient's age or basal FSH level and 2) to evaluate its role in detecting abnormal ovarian response. Design: Prospective study in 118 patients undergoing IVF-ET using GnRH-a short protocol during May-September 1995. Materials and Methods: After blood sampling for basal FSH and estradiol $(E_2)$ on cycle day two, 0.5ml (0.525mg) GnRH agonist ($Suprefact^{(r)}$, Hoechst) was injected subcutaneously. Serum $E_2$ was measured 24 hours later. Initial $E_2$ difference $({\Delta}E_2)$ was defined as the change in $E_2$ on day 3 over the baseline day 2 value. Sixteen patients with ovarian cyst or single ovary or incorrect blood collection time were excluded from the analysis. The patients were divided into three groups by ${\Delta}E_2$; group A (n=30):${\Delta}E_2$<40 pg/ml, group B (n=52): 40 pg/ml${\leq}{\Delta}E_2$<100 pg/ml, group C (n=20): ${\Delta}E_2{\leq}100$ pg/ml. COH was done by GnRH agonist/HMG/hCG and IVF-ET was followed. Ratio of $E_2$ on day of hCG injection over the number of ampules of gonadotropins used ($E_2hCGday$/Amp) was regarded as ovarian responsiveness. Poor ovarian response and overstimulation were defined as $E_2$ hCGday less than 600 pg/ml and greater than 5000 pg/ml, respectively. Results: Mean age $({\pm}SEM)$ in group A, B and C were $33.7{\pm}0.8^*,\;31.5{\pm}0.6\;and\;30.6{\pm}0.5^*$, respectively ($^*$: p<0.05). Mean basal FSH level of group $A(11.1{\pm}1.1mlU/ml)$ was significantly higher than those of $B(7.4{\pm}0.2mIU/ml)$ and C $(6.8{\pm}0.4mIU/ml)$ (p<0.001). Mean $E_2hCGday$ of group A was significantly lower than those of group B or C, i.e., $1402.1{\pm}187.7pg/ml,\;3153.2{\pm}240.0pg/ml,\;4078.8{\pm}306.4pg/ml$ respectively (p<0.0001). The number of ampules of gonadotropins used in group A was significantly greater than those in group B or C: $38.6{\pm}2.3,\;24.2{\pm}1.1\;and\;18.5{\pm}1.0$ (p<0.0001). The number of oocytes retrieved in group A was significantly smaller than those in group B or C: $6.4{\pm}1.1,\;15.5{\pm}1.1\;and\;18.6{\pm}1.6$, respectively (p<0.0001). By stepwise multiple regression, only ${\Delta}E_2$ showed a significant correlation (r=0.68, p<0.0001) with $E_2HCGday$/Amp, while age or basal FSH level were not significant. Likewise, only ${\Delta}E_2$ correlated significantly with the number of oocytes retrieved (r=0.57, p<0.001). All four patients whose COH was canceled due to poor ovarian response belonged to group A only (Fisher's exact test, p<0.01). Whereas none of 30 patients in group A (0%) had overstimulation, 14 patients among 72 patients (19.4%) in group B and C had overstimulation (Fisher's exact test, p<0.01). Conclusions: These data suggest that initial $E_2$ difference after GAST may be a better prognostic indicator of ovarian response to COH than age or basal FSH level. Since initial $E_2$ difference demonstrates significant association with abnormal ovarian response such as poor ovarian response necessitating cycle cancellation or overstimulation, GAST may be helpful in monitoring and consultation of patients during COH in IVF-ET cycle.

• Clinical and Experimental Reproductive Medicine
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• 제31권2호
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• pp.133-139
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• 2004

Objective: To investigate the association of FSH receptor (FSHR) polymorphism at position 680 with outcomes of controlled ovarian hyper-stimulation for IVF-ET in Korean women. Design: Genetic polymorphism analysis. Materials and Methods: The FSHR polymorphism was analyzed by PCR-RFLP in 172 ovulatory women below the age of 40 year. Patients with polycystic ovary syndrome, endometriosis, or previous history of ovarian surgery were excluded. Results: Genotype distribution was 41.9% for the Asn/Asn, 47.7% for the Asn/Ser, and 10.5% for the Ser/Ser FSHR genotype group. There was no difference in age of subjects and infertility diagnosis between genotype groups. When the patients were grouped according to their FSHR genotype, the basal levels of FSH (day 3) were significantly different among the three groups ($6.0{\pm}0.3\;IU/L$ (mean $\pm$ SEM), $5.8{\pm}0.3\;IU/L$, and $8.6{\pm}1.2\;IU/L$ for the Asn/Asn, Asn/Ser, and Ser/Ser groups, respectively, p=0.002). The Ser/Ser group showed a higher total doses of gonadotropins required to achieve ovulation induction, and a lower serum estradiol levels at the time of hCG administration compared with other two groups, but the differences were of no statistical significance. The numbers of oocytes retrieved were significantly different among the three groups ($8.6{\pm}0.8$, $9.9{\pm}0.6$, and $6.3{\pm}0.9$, for the Asn/Asn, Asn/Ser, and Ser/Ser groups, respectively, p=0.049). Clinical pregnancy rates were 42.4%, 25.9%, and 29.4% for the Asn/Asn, Asn/Ser, and Ser/Ser groups, respectively. Conclusion: Homozygous Ser/Ser genotype of FSHR polymorphism at position 680 was associated with decreased ovarian response to gonadotropin stimulation for IVF-ET.

• 대한화학회지
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• 제64권2호
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• pp.67-73
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• 2020

In vitro 조건 하에서 두 종류의 실리콘 하이드로 겔 렌즈인 1-day lenses(Acuvue Oasys)와 3-days lenses(Davich Trevues)의 시간 경과에 따른 지방 침착물 양과 광학적 특성 변화를 비교하였다. 인공 누액은 실제의 눈물의 조성비를 기준으로 준비하였으며, 일회용 렌즈(1-day lenses: senofilcon A)와 3일착용 렌즈(3-days lenses: silicone tripolymer)를 준비된 인공 누액에 담구어 배양기에서 37 ℃, 150 rpm의 속도로 흔들어 주면서 8 h, 16 h, 24 h 동안 침지 시켰다. 추출한 지방 침착물은 HPLC를 이용하여 지방성분을 분리하고 정량 하였다. 추가적으로 시간 경과에 따른 산소 투과율, 광 투과율, 표면 변화를 관찰하였다. 침착 된 지방의 총량은 1-day lenses가 1일차 127.55 ㎍/lens, 2일차 302.96 ㎍/lens, 3일차 353.30 ㎍/lens이었다. 3-days lenses는 1일차 46.22 ㎍/lens, 2일차 66.07 ㎍/lens, 3일차 67.45 ㎍/lens이었다. 지방 침착량은 1-3일 모두에서 3-days lenses가 적었다. 산소 투과도(Dk/t)는 최초 1-day lenses가 81×10^-9(cm/sec)(mlO₂/ml × mmHg), 3-days lenses가 13.23×10^-9(cm/sec)(mlO₂/ml×mmHg)로 3-days lenses가 현저하게 낮았으며, 3일차 1-day lenses는 48×10^-9(cm/sec)(mlO₂/ml × mmHg), 3-days lenses가 9.6 ×10^-9(cm/sec)(mlO₂/ml×mmHg)이었다. 가시광선 투과율은 최초 1-day lenses가 97.21%, 3-days lenses가 97.65%였으며, 3일차 1-day lenses가 94.25%, 3-days lenses가 95.15%로 나타났다. 시간 경과 별 표면 변화를 확대 관찰 시 3-days lenses의 표면에 보다 많은 침착물이 관찰되었다. 이로써 1-day lenses와 비교하여 3-days lenses의 3일 착용 시 지방 침착량은 적었으나, 표면 침착물은 3-day lenses에서 보다 많이 관찰되었으며, 이는 지방 침착물 외 다른 침착물이 더 많았을 것으로 판단된다.

• 치위생과학회지
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• 제17권4호
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• pp.283-289
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• 2017

DUWL에 형성한 바이오필름을 효율적으로 제거할 수 있는 새로운 소독제는 개발되어야 하며, 실험실에서 소독제의 효과를 확인하기 위해 DUWL 바이오필름 시료는 필요하다. 이 연구의 목적은 well plate를 사용하여 간단하고 재현 가능한 DUWL 바이오필름 모델을 개발하는 것이다. 사용중인 4대의 DUWL에서 배출된 1 L의 물을 여과지에 여과시켜 세균을 얻었다. 여과지를 PBS (pH 7.4) 용액 20 ml에 현탁시킨 후, 현탁액을 R2A 액체배지에 접종하고 $25^{\circ}C$에서 10일 동안 배양하였다. 10일 배양한 세균 배양액을 $-70^{\circ}C$에 보관하였고 매 실험에 사용하였다. 세균배양액을 R2A 배지에서 5일 동안 회분 배양하였다. 12-well plate에 회분 배양한 세균 배양액과 멸균한 폴리우레탄 튜빙 조각을 넣고 정체된 상태로 $25^{\circ}C$에서 바이오필름을 형성시켰다. R2A 액체배지는 2일마다 2 ml씩 교체해주었다. 폴리우레탄 내형성된 바이오필름의 축적량을 확인하기 위해 폴리우레탄 튜빙 조각을 내면에서 수집한 바이오필름을 R2A 고체배지에 도말하였다. 도말한 R2A 고체배지는 $25^{\circ}C$에서 7일 배양하고 $CFU/cm^2$를 계산하였다. 그리고 바이오필름의 두께와 구성 세균의 형태 및 분포를 확인하기 위해 CLSM과 SEM을 사용하였다. 4일 동안 배양시킨 바이오필름의 평균 축적량은 $1.15{\times}10^7CFU/cm^2$였다. 바이오필름은 구균, 짧은 길이의 간균, 그리고 중간길이의 간균을 포함하고 있었고 폴리우레탄 튜빙 내면에 넓게 분포하고 있었다. 바이오필름두께는 위치에 따라 차이가 있지만 $2{\mu}m{\sim}7{\mu}m$였다. 이 연구에서 제작된 DUWL 바이오필름 model은 DUWL에서 수집된 모든 세균을 사용하여 세균의 다양성을 확보했고 또한 실험실에서 쉽게 구할 수 있는 well-plate를 사용했기 때문에 비용 효율적이고 재현이 간단하다. 본 연구의 DUWL 바이오필름 모델은 새로운 소독방법의 개발하는 데 유용하게 사용될 수 있다.

• 한국광학회지
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• 제14권1호
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• pp.23-32
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• 2003

타원법(ellipsometry)을 사용하여 광기록 매체용 Ge$_2$ Sb$_2$ Te$^{5}$ (GST) 박막의 성장과정에 따른 타원상수 Ψ와 $\Delta$를 측정하여. GST 박막의 최적성장조건을 연구하였다. 아르곤기체압력과 DC 출력 그리고 기판의 온도를 변화시키면서 GST 박막을 성장시켰다. 제작된 시료들의 분광타원 데이터를 모델링 분석하여 GST박막의 밀도분포를 구하고 한편으로는 GST 박막이 성장하는 동안 측정한 in situ 타원 성장곡선을 분석하여 박막의 밀도분포의 변화를 추적하였다. 아르곤기체압력이 7 mTorr일 때 박막의 상대적인 밀도분포가 고르게 되었고 DC출력이 증가함에 따라 그리고 기판의 온도가 증가함에 따라 GST 박막의 밀도 균일성은 크게 향상되었다. 주사형전자현미경(SEM)을 사용하여 최적 밀도 균일성을 가지는 성장조건(7 mTorr, 45 W, 15$0^{\circ}C$)에서 제작된 GST 시료가 가장 균일한 구조를 보여줌을 확인하였다. 균일한 밀도 분포를 가지는 GST 박막의 성장조건 확립을 통하여 여러번 기록/재생할 때 광기록 박막의 안정성을 유지하는데 크게 기여할 것이다.