http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Nanomeniscus-induced delivery of liquid solutions for diverse nanofiber fabrication
An Sangmin,Kim Bongsu,Kwon Soyoung,Lee Kunyoung,Kim Jongwoo,안희준,제원호 나노기술연구협의회 2015 Nano Convergence Vol.2 No.13
Nanomaterial-delivery fabrication expects high-potential impacts on nanoscience, technology and industry, but still faces limited applicability mainly due to high-field requirement for liquid delivery, complicated intermediate processes, and narrow ink selectivity. Here, we demonstrates a simple, non-template, non-contact and electric field-free fabrication of diverse nanofibers. The process consists of continuous, meniscus-assisted delivery of liquid solutions through a nanoapertured nozzle in ambient conditions, followed by subsequent evaporation of liquid and aggregation of nanoparticle residues. For example, the carbon-nanotube nanofibers of 500 nm diameter exhibit a high shear modulus of ~1.5 GPa and current density up to 10 4 A/cm 2 . The results provide a unique, universal and versatile tool with wide selectivity in both ink and substrate.
Effective roles of native and Korean English teachers in the videoconferencing classrooms
Lee,Sangmin 한국초등영어교육학회 2010 초등영어교육 Vol.16 No.3
This paper reports on an investigation of teachers’ roles in videoconferencing classrooms. The videoconferencing program has been implemented in English classrooms since 2008 by the Ministry of Education, Science, and Technology to mitigate unequal access to English education between urban schools and countryside schools. This study analyzed 43 elementary school teachers’ videos and documents to examine co-teaching types in the videoconferencing classrooms. Among the random, non-focus group teachers, six expert teachers were selected to be role models during planning, in-class and after-class periods. For the analysis of the expert group (focus group), the Delphi method was conducted, and additional data were collected including questionnaires, interviews, workshops, and detailed lesson plans. The study revealed that there were clear differences between the focus group and the non-focus group regarding co-teachers’roles. The focus group teachers exhibited more effective and feasible co-teaching models, in which the native speaking teachers led the class and the Korean teachers supported and assisted. Particularly, the Korean teachers adapted flexible roles, shifting from facilitator to assistant to monitor, depending on the situations. The paper also includes suggestions for successful co-teaching in a videoconferencing classroom.
비실시간 온라인 영어 수업에 대한 고등학교 학생과 교사의 인식 비교 연구
이상민 ( Lee¸ Sangmin ),정양수 ( Jung¸ Yang-soo ) 한국현대언어학회 2021 언어연구 Vol.37 No.2
The Journal of Studies in Language 37.2, 181-196. A Comparative Study on the Perceptions of Korean High School Students and Teachers about Asynchronous Online English Classes. The purpose of this study is to compare the perceptions of students and teachers about the current online English teaching and learning since the outbreak of COVID-19. For this study, questionnaires have been used for 513 students and 10 teachers of a girls’ high school located in “D” city, South Korea. The results are as follows: First, there were no significant differences in student and teacher perceptions depending on the subcategories of online English learning. Second, both groups showed the average level of satisfaction with online English classes. Third, both groups showed the necessity for encouraging interaction among class participants. Considering the results above, interaction among class participants should be encouraged by either implementing synchronous mode of class or any other way. This research was based solely on the asynchronous mode of online education with class video contents, so it was not able to comprise other varieties of online learning. (Chongchon High School · Chungnam National University)
Walking: The New Tool for Analyzing Museum Visitors
Sangmin Lee(Sangmin Lee) 한국아세아태평양교육문화융복합학회 2022 Asia Pacific Journal of Teaching and Learning Vol.2 No.2
Purpose This study aims to research walking as a new tool for visitor analysis in the museums. Method After literature review, multiple case study methodology with some components of duoethnographic arts-based research were employed for this research. The data, including walking videos, photo journals, and dialogues at several museums, were collected and analyzed qualitatively. Results Museum visitors' walking can be categorized in five types - browsing walking, relational walking, analytical walking, recreational walking, and virtual walking. Each type has one or two sub-categories to shed light on visitors' walking patterns. Conclusion Museum staffs and educators will be able to use walking analysis as supporting data for making decision on their program development, exhibition planning, and spatial arrangement to improve visitors' museum experience.
Lee, Tae Il,Lee, Sangmin,Lee, Eungkyu,Sohn, Sungwoo,Lee, Yean,Lee, Sujeong,Moon, Geondae,Kim, Dohyang,Kim, Youn Sang,Myoung, Jae Min,Wang, Zhong Lin WILEY‐VCH Verlag 2013 ADVANCED MATERIALS Vol.25 No.21
<P><B>A high‐yield solution‐processed ultrathin (<10 nm) trigonal tellurium (t‐Te) nanowire (NW)</B> is introduced as a new class of piezoelectric nanomaterial with a six‐fold higher piezoelectric constant compared to conventional ZnO NWs for a high‐volume power‐density nanogenerator (NG). While determining the energy‐harvesting principle in a NG consisting of t‐Te NW, it is theoretically and experimentally found that t‐Te NW is piezoelectrically activated only by creating strain in its radial direction, along which it has an asymmetric crystal structure. Based upon this mechanism, a NG with a monolayer consisting of well‐aligned t‐Te NWs and a power density of 9 mW/cm<SUP>3</SUP> is fabricated.</P>
Tumor-Homing Glycol Chitosan-Based Optical/PET Dual Imaging Nanoprobe for Cancer Diagnosis
Lee, Sangmin,Kang, Sun-Woong,Ryu, Ju Hee,Na, Jin Hee,Lee, Dong-Eun,Han, Seung Jin,Kang, Choong Mo,Choe, Yearn Seong,Lee, Kyo Chul,Leary, James F.,Choi, Kuiwon,Lee, Kyung-Han,Kim, Kwangmeyung American Chemical Society 2014 Bioconjugate chemistry Vol.25 No.3
<P>Imaging techniques including computed tomography, magnetic resonance imaging, and positron emission tomography (PET) offer many potential benefits to diagnosis and treatment of cancers. Each method has its own strong and weak points. Therefore, multimodal imaging techniques have been highlighted as an alternative method for overcoming the limitations of each respective imaging method. In this study, we fabricated PET/optical activatable imaging probe based on glycol chitosan nanoparticles (CNPs) for multimodal imaging. To prepare the dual PET/optical probes based on CNPs, both <SUP>64</SUP>Cu radiolabeled DOTA complex and activatable matrix metalloproteinase (MMP)-sensitive peptide were chemically conjugated onto azide-functionalized CNPs via bio-orthogonal click chemistry, which was a reaction between azide group and dibenzyl cyclooctyne. The PET/optical activatable imaging probes were visualized by PET and optical imaging system. Biodistribution of probes and activity of MMP were successfully measured in tumor-bearing mice.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/bcches/2014/bcches.2014.25.issue-3/bc500020g/production/images/medium/bc-2014-00020g_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/bc500020g'>ACS Electronic Supporting Info</A></P>
Voltage balancing control of a series‑resonant DAB converter with a virtual line shaft
Sangmin Lee,Woonjung Hong,Taewan Kim,Gil-Dong Kim,Eun S. Lee,Seung-Hwan Lee 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.8
A multilevel series-resonant dual-active bridge (SRDAB) converter is widely used in high-voltage and high-power systems to reduce the voltage stress of inverter switches. However, an imbalance in the DC-link voltage between the DAB converters can cause system failure because inverter switches can be destroyed by voltage and current stress. In this study, a virtual line shaft (VLS) control is proposed to achieve output voltage and power balance between SRDAB converter modules. The gains of the controllers are selected using the frequency responses of the controllers. The disturbance rejection performance of the virtual line shaft and cross-coupling controller is compared. To evaluate the performance of the controllers, the timedomain responses of the VLS and cross-coupling controllers are compared. The simulated and experimental results show that the output voltages of the SRDAB modules are well balanced. The proposed voltage controller regulates the output voltage of an SRDAB module within 20 ms. The output voltages of the SRDAB modules are synchronized well even under asynchronous load changes.
Lee, Hyungsoo,Choi, Jin Hyeok,Jo, Min Chul,Lee, Donghyun,Shin, Sangmin,Jo, Ilguk,Lee, Sang-Kwan,Lee, Sunghak Elsevier 2018 Materials science & engineering. properties, micro Vol.738 No.-
<P><B>Abstract</B></P> <P>Quasi-static and dynamic compressive properties of 7075-T6 Al matrix composites reinforced with SiC<SUB>p</SUB>s (size; 10 µm, 30 µm, and bimodal (10 + 30) μm), <I>i.e</I>., 10S, 30S, and BS composites, respectively, were investigated in relation with fracture mechanisms. SiC<SUB>p</SUB>s were homogeneously distributed without SiC<SUB>p</SUB> agglomeration, pores, or cracks, and their volume fractions were 49.5 vol%, 54.1 vol%, and 56.5 vol% in the 30S, 10S, and BS specimens, respectively. Compressive properties could be explained by a rule of mixtures based on SiC<SUB>p</SUB> volume fraction and by three major fracture phenomena including deformation of Al matrix, cracking of SiC<SUB>p</SUB>s, and interfacial debonding between SiC<SUB>p</SUB> and Al. As the SiC<SUB>p</SUB> size decreased, crack initiation sites changed from SiC<SUB>p</SUB>s themselves to SiC<SUB>p</SUB>/Al interfaces, which mainly affected the compressive strength. In the BS composite, coarse SiC<SUB>p</SUB>s additionally worked for the strengthening by increasing the total reinforcement fraction, and the three fracture phenomena were well homogenized, thereby leading to the highest strain energy density as well as the best combination of strength and strain.</P>