Global citizenship and community engagement through global service-learning

Service-Learning(S-L) may enable participants to have more concerns for others and try to engage in the community as they find their roles. Global Service-Learning (GS-L) provided university students with the opportunity to experience global problems that were unfamiliar to them now, but will help motivate them to explore possible solutions for future use. Global citizenship is based not on the knowledge from books but on experience and engagement in real world situations. This study explores the experiences and learning of students who conducted GS-L outreach for two weeks in Mongolia. A survey instrument, follow-up discussions and reflective journals were used to assess their changes. Their responses showed that GS-L challenged them to have wider perspectives on this diverse world and motivated them to make wider community engagement as good global citizens. Students responded that they wanted to be more active participants i n global issue related programs and to learn foreign languages to communicate with diverse range of people in the world

Synthesis of π-extended low bandgap polymer based on isoindigo and thienyl-vinylene for high-performance polymer solar cells

246th ACS National Meeting and Exposition September 8-12, 2013, Indianapolis, IndianaIn this presentation, we report a novel π-extended low bandgap polymer, PITVT, which is composed of isoindigo and thienylvinylene. The polymer exhibits a high power conversion efficiency of 7.09% for polymer solar cells (PSCs). The high performance is achieved by strong intermolecular π-π stacking from coplanarity of thienylvinylene in polmyer backbone, and the deep HOMO energy level of PITVT. This work clearly demonstrates that the incorporation of π-extended thienylvinylene moiety in conjugated polymer backbone improves the performance of PSCs.OAIID:oai:osos.snu.ac.kr:snu2013-01/104/0000001236/17SEQ:17PERF_CD:SNU2013-01EVAL_ITEM_CD:104USER_ID:0000001236ADJUST_YN:NEMP_ID:A004558DEPT_CD:445CITE_RATE:0FILENAME:정의혁 포스터 초록.pdfDEPT_NM:재료공학부EMAIL:[email protected]:

Isoindigo as a Building Block for Semiconducting Conjugated Polymers for High Performance Organic Photovoltaics

One of the most important issues for enhancing the power conversion efficiency (PCE) of polymer solar cells (PSCs) is the development of conjugated polymers which exhibit broad light absorption with strong absorptivity, high charge carrier mobility, suitable energy level matching with the electron acceptor (fullerene derivatives), and appropriate molecular orientation to form an optimum pathway of charge carriers to the corresponding electrodes. In past few years, remarkable progress in the PCE surpassing 8% have been achieved with the configuration of bulk-heterojunction network structure consisting of high performance conjugated polymer as an electron donor and fullerene derivative as an acceptor. Isoindigo is a dye molecule with two lactam rings pertaining strong electron-withdrawing characteristic and planar ∏-conjugated structure. Particularly, the planar molecular structure is expected to afford high charge carrier mobility. Moreover, isoindigo-based organic compounds show broad optical absorption, high extinction coefficient, and deep HOMO energy level. Therefore, isoindigo is a promising building block for constructing low bandgap conjugated polymers to achieve high performance PSCs.OAIID:oai:osos.snu.ac.kr:snu2014-01/104/0000001236/4SEQ:4PERF_CD:SNU2014-01EVAL_ITEM_CD:104USER_ID:0000001236ADJUST_YN:NEMP_ID:A004558DEPT_CD:445CITE_RATE:0FILENAME:초록및프로그램_5월프랑스.pdfDEPT_NM:재료공학부CONFIRM:

Effect of interlayer interactions on exciton luminescence in atomic-layered MoS2 crystals

The atomic-layered semiconducting materials of transition metal dichalcogenides are considered effective light sources with both potential applications in thin and flexible optoelectronics and novel functionalities. In spite of the great interest in optoelectronic properties of two-dimensional transition metal dichalcogenides, the excitonic properties still need to be addressed, specifically in terms of the interlayer interactions. Here, we report the distinct behavior of the A and B excitons in the presence of interlayer interactions of layered MoS 2 crystals. Micro-photoluminescence spectroscopic studies reveal that on the interlayer interactions in double layer MoS 2 crystals, the emission quantum yield of the A exciton is drastically changed, whereas that of the B exciton remains nearly constant for both single and double layer MoS 2 crystals. First-principles density functional theory calculations confirm that a significant charge redistribution occurs in the double layer MoS 2 due to the interlayer interactions producing a local electric field at the interfacial region. Analogous to the quantum-confined Stark effect, we suggest that the distinct behavior of the A and B excitons can be explained by a simplified band-bending model.1

High Performance n-Channel Organic Field-Effect Transistor of Conjugated Polymers with Fluorine-Substituted Phenylene Unit

OAIID:oai:osos.snu.ac.kr:snu2013-01/104/0000001236/9SEQ:9PERF_CD:SNU2013-01EVAL_ITEM_CD:104USER_ID:0000001236ADJUST_YN:NEMP_ID:A004558DEPT_CD:445CITE_RATE:0FILENAME:20130328_한국영국교류_(120x90)_정의혁.pdfDEPT_NM:재료공학부EMAIL:[email protected]:

Do We Have to Close Residual Patent Ductus Arteriosus After Surgery or Transcatheter Intervention?

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Predictors and patterns of problematic Internet game use using a decision tree model

Background and aims Problematic Internet game use is an important social issue that increases social expenditures for both individuals and nations. This study identified predictors and patterns of problematic Internet game use. Methods Data were collected from online surveys between November 26 and December 26, 2014. We identified 3,881 Internet game users from a total of 5,003 respondents. A total of 511 participants were assigned to the problematic Internet game user group according to the Diagnostic and Statistical Manual of Mental Disorders Internet gaming disorder criteria. From the remaining 3,370 participants, we used propensity score matching to develop a normal comparison group of 511 participants. In all, 1,022 participants were analyzed using the chi-square automatic interaction detector (CHAID) algorithm. Results According to the CHAID algorithm, six important predictors were found: gaming costs (50%), average weekday gaming time (23%), offline Internet gaming community meeting attendance (13%), average weekend and holiday gaming time (7%), marital status (4%), and self-perceptions of addiction to Internet game use (3%). In addition, three patterns out of six classification rules were explored: cost-consuming, socializing, and solitary gamers. Conclusion This study provides direction for future work on the screening of problematic Internet game use in adults