Nonlinear optical properties of mushroom-shaped CdSe/CdS coreshells.

Ma, S M,Seo, J T,Yu, W,Yang, Q,Tabibi, B,Temple, D,Namkung, M,Heo, J,Kim, W J,Jung, S S American Scientific Publishers 2009 Journal of Nanoscience and Nanotechnology Vol.9 No.2

<P>The third-order nonlinear optical susceptibilities of mushroom-shaped CdSe/CdS coreshells as a function of concentration have been investigated using polarization- and concentration-resolved degenerate four-wave mixing in a resonant region. The effective third-order nonlinear optical susceptibilities, /chi(3)xxxx/ and /chi(3)xyyx/ of CdSe/CdS coreshells were estimated to be approximately 1.86 x 10(-21)-1.03 x 10(-20) m2/V2, and approximately 0.45 x 10(-21)-6.15 x 10(-21) m2/V2, respectively, for various concentrations of approximately 0.64 x 10(-3)-4.95 x 10(-3) mol/m3. The second hyperpolarizabilities, /<gammah>xxxx/ and /<gammah>xyyx/, of CdSe/CdS coreshells were extracted to be approximately 2.37 x 10(-41) m5/V2 and approximately 1.29 x 10(-41) m5/V2, respectively.</P>

Proposed searches for candidate sources of gravitational waves in a nearby core-collapse supernova survey

Heo, J.E.,Yoon, S.,Lee, D.S.,Kong, I.t.,Lee, S.H.,van Putten, M.H.P.M.,Della Valle, M. Elsevier 2016 New astronomy Vol.42 No.-

<P>Gravitational wave bursts in the formation of neutron stars and black holes in energetic core-collapse supernovae (CC-SNe) are of potential interest to LIGO-Virgo and KAGRA. Events nearby are readily discovered using moderately sized telescopes. CC-SNe are competitive with mergers of neutron stars and black holes, if the fraction producing an energetic output in gravitational waves exceeds about 1%. This opportunity motivates the design of a novel Sejong University Core-CollapsE Supernova Survey (SUCCESS), to provide triggers for follow-up searches for gravitational waves. It is based on the 76 cm Sejong university telescope (SUT) for weekly monitoring of nearby star-forming galaxies, i.e., M51, M81-M82 and blue dwarf galaxies from the unified nearby galaxy catalog with an expected yield of a few hundred per year. Optical light curves will be resolved for the true time-of-onset for probes of gravitational waves by broadband time-sliced matched filtering. (C) 2015 Elsevier B.V. All rights reserved.</P>

Enhancement of Chromosome Aberrations in Lymphocytes of Mice after In Vivo Exposure to Chemicals and In Vitro Challenge with Bleomycin

Heo, M.Y.,J.J.Grady,W.W.Au A.R. Liss 1998 ENVIRONMENTAL MUTAGENS AND CARCINOGENS Vol.18 No.2

Comparison between effect of B and N on the microstructure of modified 9Cr-2W steel during aging and creep

Heo, H.M.,Jeong, E.H.,Kim, S.H.,Kim, J.R. Elsevier Sequoia 2016 Materials science & engineering. properties, micro Vol.670 No.-

<P>This paper reports on microstructural degradation by aging and creep, specifically with different B and N content in modified 9Cr-2W steels. This study used TEM to examine the growth and generation of precipitates across chemical composition changes resulting from aging and creep. The coarsening of precipitates, mainly M23C6, was evaluated during aging and creep, and the role of B and N on micro structural change during aging and creep was investigated. (C) 2016 Elsevier B.V. All rights reserved.</P>

간호대생들의 임상실습 스트레스, 학업적 자기효능감 및 진로정체감에 대한 연구

최유빈,최민지,이은형,이연우,우소연,하희주,허예지,박수현,허미래,이가현 이화여자대학교 간호과학대학 2015 이화간호학회지 Vol.- No.49

Purpose: The purpose of this study was to investigate clinical practice stress, academic self-efficacy, and career identity among undergraduate students in nursing practicum. Method: This study was a descriptive correlational design using the survey method. The study included 267 undergraduate students attending to 5 college in Seoul. The data was gathered from August 2014 to October 2014 and the data were analyzed using IBM SPSS statistics version 22.0 Program with descriptive statistics, t-test, analysis of variance with Scheffe test, and Pearson’s correlation coefficient. Results: Situational characteristics of Clinical Practice Stress(CPP) was significantly different with regards to task difficulties and efficacy self-confidence of academic self-efficacy(ASE) (r= .179, p= .003; r= .166, p= .006). Statistically significant positive relationship was founded between Personal characteristics of CPP and self-confidence of ASE (r= .239, p< .01). External regulators of CPP was significantly different according to self-confidence and task difficulties (r= .175, p= .003; r= .132, p= .028). The self-confidence and efficacy for self-confidence of ASE were a significantly correlated with Career Identity; The Career identity also was a significantly correlated with all sub-categories of CSS scale(r= -0.208, p< 0.01; r= -0.369, p< 0.01; r= -0.153, p< .011) Conclusion: This study showed positive statistical relationships associated with clinical practice stress, academic self-efficacy, and career identity as a preliminary evidence-based study for guiding education in nursing curriculum. Further research should be need for students’ future as a professional nurse.

Workspace analysis of a 6-DOF cable-driven parallel robot considering pulley bearing friction under ultra-high acceleration

Heo, J. M.,Choi, S. H.,Park, K. S. Springer Science + Business Media 2017 Microsystem Technologies Vol.23 No.7

<P>Cable robots can generate high velocities and accelerations due to the very small inertia of the end-effector. Therefore, CDPRs have been used widely in special industrial applications requiring high dynamics. However, the high acceleration generated affects the wrench-feasible workspace of a CDPR system significantly. In addition, as a pulley rotates, the frictional force at the pulley bearing disturbs the motion, changes the cable tensions. Thus, pulley bearing friction cannot be neglected in ultra-high acceleration systems where high tensions are imposed. A workspace analysis was carried out for a wrench-feasible condition in a 6-DOF CDPR system considering the pulley bearing friction connected in series. Then, the pulley bearing friction was modeled with the Coulomb friction model including the variation of wrapping angle of pulley and a loss factor. The simulated tension profiles considering pulley bearing friction were in good agreement with data measured with a load cell. And a wrench-feasible workspace analysis under various accelerations was carried out. In conclusion, as the external acceleration was increased, the whole tension was increased and workspaces to exceed available tension occurred in case of 100 m/s(2). And the pulley bearing force increased or decreased the cable tension because of the direction of the signum function. As a result, the wrench-feasible workspace was changed in the presence of pulley bearing force effects.</P>

20대 성인의 페이스북 이용행태에 따른 사회비교 경향성, 우울,자아존중감

김지원,남궁빈,안해정,권햇살,한예슬,허진성,김고은,김수진,김미혜,이수인 이화여자대학교 간호과학대학 2015 이화간호학회지 Vol.- No.49

Purpose: The purpose of this study was to explore the differences among social comparison orientation, depression, and self-esteem by patterns of using Facebook among Facebook users’ in their 20s. Methods: The participants in this descriptive study were 332 Facebook users in their 20s. Data collection took place between August 21 and 27, 2014. Questionnaires were the Iowa–Netherlands Comparison Orientation Measure (revised), Center for Epidemiologic Studies Depression Scale, and Rosenberg Self-Esteem Scale. Data were statistically analyzed using t-tests and ANOVAs. Result: Each mean score of social comparison, depression, and self-esteem was 26.04±6.82, 31.39±8.99 and 38.05±6.19. Significant differences emerged between the degree of social comparison and the following Facebook usage variables: average single-connection time to Facebook (F=3.570, p=.007) and self-evaluation of Facebook usage behavior (F=6.203, p<.001). Conclusion: The results of this study suggested that Facebook users in their 20s who access Facebook for long periods and assess themselves as using it more often had a high score of comparison orientation. This result can be used in Nursing by developing the theoretical basis for education and campaign related to Facebook usage. In-depth studies are needed for research on the effect social comparison has on Facebook users and relationships between social comparison and emotions.

50μm급 마이크로렌즈 적용 2인치 휴대폰 LCD-BLU 금형 개발 : 광학패턴의 세장비 영향

김종선,고영배,민인기,유재원,허영무,윤경환,황철진,Kim, J.S.,Ko, Y.B.,Min, I.K.,Yu, J.W.,Heo, Y.M.,Yoon, K.H.,Hwang, C.J. 한국소성가공학회 2007 소성가공 : 한국소성가공학회지 Vol.16 No.1

LCD-BLU(Liquid Crystal Display - Back Light Unit) consists of several optical sheets: LGP(Light Guiding Plate), light source and mold frame. The LGP of LCD-BLU is usually manufactured by etching process and forming numerous dots with $50{\mu}m$ in diameter on the surface. But the surface roughness of LGP with etched dots is very high, so there is much loss of light. In order to overcome the limit of current etched dot patterned LGP, optical pattern design with microlens of $50{\mu}m$ diameter was applied in the present study. The microlens pattern fabricated by modified LiGA with thermal reflow process was applied to the optical design of LGP and optical simulation was carried out to know tendency of microlens patterned LGP simultaneously. The attention was paid to the effects of different aspect ratio(i.e. $0.2\sim0.5$) of optical pattern conditions to the brightness distribution of BLU with microlens patterned LGP. Finally, high aspect ratio microlens patterned LGP showed superior results to the one made by low aspect ratio in average luminance.

Synthesis of triarylamine-based alternating copolymers for polymeric solar cell

Lee, J.,Cha, H.,Kong, H.,Seo, M.,Heo, J.,Jung, I.H.,Kim, J.,Shim, H.K.,Park, C.E.,Kim, S.Y. IPC Science and Technology Press 2014 Polymer Vol.55 No.19

Two donor-acceptor alternating copolymers based on electron-rich triarylamine, di(1-(6-(2-ethylhexyl))naphthyl)phenylamine (DNPA), and electron-deficient benzothiadiazole and benzoselenadiazole derivatives were designed and synthesized via Suzuki coupling reaction. The resulting triarylamine-based alternating copolymers PDNPADTBT and PDNPADTBS showed good solubility in common organic solvents and good thermal stability. The optical band gaps determined from the onset absorption were 1.93 and 1.81 eV, respectively. By introducing the naphthalene ring into the triarylamine, copolymers had relatively deep HOMO energy levels of -5.48 and -5.45 eV, which led to a high open circuit voltage (V<SUB>oc</SUB>) and good air stability for photovoltaic application. Bulk heterojunction solar cells were fabricated with a structure of ITO/PEDOT-PSS/copolymers-PC<SUB>70</SUB>BM/LiF/Al by blending the copolymer with PC<SUB>70</SUB>BM. Both blend systems showed remarkably high V<SUB>oc</SUB> near 0.9 V, and the highest performance of 2.2% was obtained from PDNPADTBT, with V<SUB>oc</SUB> = 0.88 V, J<SUB>sc</SUB> = 7.4 mA/cm<SUP>2</SUP>, and a fill factor of 34.4% under AM 1.5 G.

Oxide-free Sb₂S₃ sensitized solar cells fabricated by spin and heat-treatment of Sb(III)(thioacetamide)₂Cl₃

You, M.S.,Lim, C.S.,Kwon, D.H.,Heo, J.H.,Im, S.H.,Chae, K.J. Elsevier Science 2015 ORGANIC ELECTRONICS Vol.21 No.-

Pure Sb<SUB>2</SUB>S<SUB>3</SUB> without oxide impurities was formed by thermal decomposition of Sb(thioacetamide: TA)<SUB>2</SUB>Cl<SUB>3</SUB> precursor. From the analysis of thermal properties of Sb(TA)<SUB>2</SUB>Cl<SUB>3</SUB>, we developed a spin-coating and heat-treatment process to form pure Sb<SUB>2</SUB>S<SUB>3</SUB> thin-films with controllable thickness due to the formation of insoluble Sb<SUB>2</SUB>S<SUB>3</SUB> by heat-treatment. Through the spin-coating and heat-treatment process, we could fabricate oxide-free Sb<SUB>2</SUB>S<SUB>3</SUB> planar type sensitized solar cell with 8.12mA/cm<SUP>2</SUP> of short circuit current density (J<SUB>sc</SUB>), 0.616V of open circuit voltage (V<SUB>oc</SUB>), 45.9% of fill factor (F.F), and overall power conversion efficiency (η) of 2.3% at 1 sun condition.