• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.404-405
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• 2011

Cu(InGa)$Se_2$ (CIGS) 박막 태양전지의 저가 및 대면적화를 위한 양산화 공정인 two-step process (sputter/selenization) 공정에서는 sputtering으로 형성한 metal precursor stack을 $H_2$ Se gas를 이용하여 selenization하는 공정을 주로 이용한다. 하지만 이러한 selenization 공정은 유독한 $H_2$ Se gas를 이용해야 한다는 점과 긴 시간 동안 열처리를 해야 하는 단점을 가지고 있다. 이에 metal precursor stack 위에 Se 막을 우선 증착하고, Rapid Thermal Process (RTP)를 이용하여 selenization하는 방법이 현재 많은 관심을 끌고 있다. 본 논문에서는 sputtering 이후 RTP를 이용한 CIGS 흡수층 제작에 대한 선행연구의 일환으로 co-evaporator 장비를 이용하여 다양한 구조의 precursor를 제작하고 RTP 조건에 따른 selenization 효과를 연구하였다. Co-evaporator를 이용하여 CIGS, CIG/Se, CuGa/In/Se, In/CuGa/Se 4가지 구조의 precursor stack을 Mo coated soda lime glass 위에 제작하였다. 이때 amorphous 상태의 precursor stack을 만들기 위하여 기판에 열은 가하여 주지 않았으며, 각각의 stack 구조에서 가지고 있는 Cu, In, Ga, Se의 총량을 동일하게 유지하기 위하여 각 stack의 증착 시간을 동일하게 유지하였다. Selenization을 위한 RTP 조건은 550, $600^{\circ}C$ 각각에 대하여 1, 5, 10분으로 split을 진행하였다. Precursor stack의 증착 후 관찰한 XRD 결과는 비정질 상태를 잘 나타내었으며, SEM 결과 CIGS precursor stack을 제외한 나머지 구조의 stack에서는 In 박막의 surface roughness로 인하여 박막의 평탄화가 좋지 않음을 확인하였다. CIGS precursor stack의 경우, RTP 온도와 시간 split와 상관없이 결정화가 잘 이루어졌으나 grain의 성장이 부족하였다. 이에 비하여 CIG/Se, CuGa/In/Se, In/CuGa/Se 구조의 precursor stack의 경우, $550^{\circ}C$ 열처리에서는 InSe의 결정상이 관찰 되었으며 $600^{\circ}C$, 5분 이상 열처리에서 CIGS 결정상이 관찰되었다. 이러한 결과는 Se이 metal 원소들과 함께 있는 CIGS 구조에 비하여 metal precursor stack 위에 Se을 증착한 stack 구조들의 경우는 CIGS 결정을 형성하기 위해 Se이 metal 층들로 확산되어 반응을 하여야 하므로 상대적으로 많은 열에너지가 필요한 것으로 이해할 수 있으며, RTP를 이용한 selenization 공정으로 CIGS 박막 태양전지의 흡수층 형성이 가능함을 확인하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.2
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• pp.47-52
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• 2017

In this paper, CMOS SAR A/D converter 1.8V supply for the design of an A/D converter having an middle speed for the biological signal processing was designed. This paper proposes design of a 10-bit SAR Analog to Digital Converter improving linearity driven by MSB node of C-DAC array divided into 4 equal parts. It enhances linearity property, by retaining the analog input signal charging time at MSB node. Because MSB node samples analog input, it enhances resolution through getting initial input signal precisely. By using split capacitor on C-DAC array, it reduced chip size and power dissipation. The Proposed SAR A/D Converter is fabricated in 0.18um CMOS and measured 7.5 bits of ENOB at sampling frequency 4MS/s and power supply of 1.8V. It occupies a core area of $850{\times}650um^2$ and consumes 123.105uW. Therefore it results in 170.016fJ/step of FOM(Figure of Merit).

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.3
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• pp.133-138
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• 2015

Objectives: To evaluate the influence of the type of osteotomy in the inferior aspect of the mandible on the mechanical performance. Materials and Methods: The study was performed on 20 polyurethane hemimandibles. A sagittal split ramus osteotomy (SSRO) was designed in 10 hemimandibles (group 1) with a vertical osteotomy in the buccal side (second molar level) and final osteotomy was performed horizontally on the lingual aspect, while the mandible body osteotomy was finalized as a straight osteotomy in the basilar area, perpendicular to the body. For group 2, the same osteotomy technique was used, but an oblique osteotomy was done in the basilar aspect of the mandibular body, forming continuity with the sagittal cut in the basilar area. Using a surgical guide, osteosynthesis was performed with bicortical screws using an inverted L scheme. In both groups vertical compression tests were performed with a linear load of 1 mm/min on the central fossa of the first molar and tests were done with models made from photoelastic resin. Data were analyzed using Student's t-test, establishing a statistical significance when P<0.05. Results: A statistical difference was not observed in the maximum displacements obtained in the two osteotomies (P<0.05). In the extensiometric analysis, statistically significant differences were identified only in the middle screw of the fixation. The photoelastic resin models showed force dissipation towards the inferior aspect of the mandible in both SSRO models. Conclusion: We found that osteotomy of the inferior aspect did not influence the mechanical performance for osteosynthesis with an inverted L system.

• Language and Information
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• v.14 no.2
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• pp.71-84
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• 2010

The aim of this paper is to propose that a category P is encapsulated within a functional layer above the lexical layer, just like vP containing a lexical VP. As is well known, the category P has long been in the obscure domain of syntactic studies: Marantz (2001) and den Dikken (2003), for example, argue that P is a lexical category, but Emonds (1985), Grimshaw (1991), and Baker (2003), maintain that the category P is functional and is a closed category without its own intrinsic meaning. On the other hand, Zwart (2005) argues that it does have some meaning. Following the works of Svenonius (2003, 2006, 2007), and the spirit of Rizzi's (1997) split CP hypothesis, we elaborate and develop Svenonius' idea of split-pP analysis with detailed schematic representations of the novel examples in English, Korean, and Chinese in this paper. Unlike Svenonius, however, this paper incorporates KP into pP-Shell, which is a substantial simplification. Furthermore, Chinese Localizers that have long been considered as Postpositions are now under the category of Prepositions. This proposal renders an X-bar theoretic consistency over the categorical status of Chinese phrasal structures. In short, the present analysis accounts for inconsistency found in English complex preposition phrase (Quirk, et al, 1972, 1985), Chinese circumposition phrase (Ernst 1988, Liu, 2002) and Korean postposition phrase in a unified and consistent manner. Furthermore, by proposing a finer-grained phrasal architecture for the category P, the controversial status of the category subsides within this analysis.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.419-424
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• 2006

본 연구는 데스크탑 PC 환경에서 사용될 수 있는 다양한 적응형 메뉴 인터페이스의 사용성을 평가한다. 선택 빈도에 따라 자동으로 변화하는 2가지 방식의 Adaptive menu와 사용자가 메뉴 내에서 원하는 항목의 위치를 직접 변경하는 Adaptable menu의 사용성을 일반적으로 많이 이용되는 Traditional menu와 비교하기 위해 사용자를 동원한 평가 실험을 수행하였다. Adaptive menu에는 선택 빈도가 높은 메뉴 항목이 메뉴의 상단으로 이동하는 Adaptive split menu와 자주 선택되는 항목이 굵은 글씨로 표현되는 Adaptive style menu가 포함된다. 각 방식의 적응형 메뉴가 자주 선택되는 메뉴 항목의 변화에 따라 얼마나 민감하게 영향을 받는지 비교하기 위해, 두 개의 각기 다른 선택 빈도 분포가 이용되었다. 각 실험 조건 별로 사용자가 메뉴 항목을 선택하는 데 걸린 시간과 오류 회수를 측정하였으며, 피실험자로 하여금 시인성, 효율성, 전반적 선호도 등의 주관적인 만족도를 평가하도록 하였다. 각각의 종속 변수들은 분산 분석(ANOVA), Chi-square test, Friedman test 등의 기법을 이용해 분석되었다. 분석 결과, Adaptable menu가 다른 방식의 메뉴들에 비해 수행도와 만족도 모두 높은 것으로 나타났으며, Adaptive split menu는 상대적으로 현실적인 조건 하에서 큰 효용을 갖지 못하는 것으로 나타났다. Adaptive style menu는 수행도 측면에서는 일반적인 메뉴와 큰 차이가 없었지만, 자주 선택되는 항목을 쉽게 파악할 수 있게 해 주고, 선택 빈도의 변화에도 민감하지 않기 때문에 사용자들에게 선호되는 것으로 나타났다. 본 연구의 결과는 데스크탑 PC의 적응형 메뉴 설계에 대한 이용될 수 있으며, 추후 휴대용 정보기기의 적응형 메뉴에 대한 사용성 연구의 기초 자료로도 활용될 수 있을 것으로 기대된다.

• Journal of Korean Academy of Nursing
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• v.46 no.3
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• pp.431-442
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• 2016

Purpose: This paper was conducted to validate the Korean version of the Peer Group Caring Interaction Scale (PGCIS-K) that measures caring behaviors as experienced by nursing students. Methods: Translation of the PGCIS-K was validated through forward-backward translation methods. Survey data were collected from 218 nursing students in a nursing school. Construct validity and criterion-related validity were evaluated. Internal consistency and the Guttman split-half coefficient were calculated to assess reliability. Results: The PGIS-K showed reliability except for 4 items (Cronbach's ${\alpha}=.91$, Guttman split-half coefficient=.85), which were low (<.30) or negatively correlated with the total scale. A 12-item reduced form of the PGCIS-K was developed by item-analysis and construct validity evidence. Factor loading for the 12 items on 2 factors ranged from .47~.82, which explained 58.4% of the total variance. Two factors were named 'modeling and assistance (Cronbach's ${\alpha}=.87$)' and 'communication and sharing (Cronbach's ${\alpha}=.82$)'. Convergent validity, discriminant validity, and criterion validity were supported according to the correlation coefficients of the 2 factors with other measure. Conclusion: The findings suggest preliminary evidence that the 12-item PGCIS-K can be used to measure nursing students' peer group caring interactions in Korea. Additional studies are recommended to continue the psychometric evaluation of this scale. Also, it can be extended to measure graduate nursing students or staff nurses' peer group caring interaction.

• 대한생식의학회:학술대회논문집
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• 2005.11a
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• pp.140.2-141
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• 2005

• International Journal of Concrete Structures and Materials
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• v.7 no.4
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• pp.287-293
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• 2013

Strength and some durability properties of concrete containing rice husk ash (RHA) predominantly composed of amorphous silica at a specific surface of 235 $m^2/kg$ produced using a charcoal incinerator were determined. The maximum ordinary Portland cement (OPC) replacement with the RHA increased with increase in water/binder (w/b) ratio of the concrete mixes. The results show that 15 % OPC could be substituted by the RHAwithout strength loss at w/b ratio of 0.50. The split tensile strength generally increased with increase in RHA content for the mixes.

• The Journal of the Korean dental association
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• v.19 no.2 s.141
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• pp.186-189
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• 1981

This is a case report of idiopathic fibromatosis on the gingiva. The patient was a 25 years old male. In this case, we had a good result from surgical excision, combining the gingivectomy and split thickness flap operation.

• Journal of the Korean Mathematical Society
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• v.45 no.2
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• pp.513-525
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• 2008

Using known properties of superquadratic functions we obtain a sequence of inequalities for superquadratic functions such as the Converse and the Reverse Jensen type inequalities, the Giaccardi and the Petrovic type inequalities and Hermite-Hadamard's inequalities. Especially, when the superquadratic function is convex at the same time, then we get refinements of classical known results for convex functions. Some other properties of superquadratic functions are also given.