http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Stochastic Photon Emission from Nonblinking Upconversion Nanoparticles
Lee, Eunsang,Jung, Minhyuk,Han, Youngeun,Lee, Gibok,Shin, Kyujin,Lee, Hohjai,Lee, Kang Taek American Chemical Society 2017 JOURNAL OF PHYSICAL CHEMISTRY C - Vol.121 No.38
<P>Because of their well-known optical properties, upconversion nanoparticles (UCNPs) are regarded as some of the most promising nano-materials for bioimaging, biosensors, and solar cells. The nonblinking nature of their upconversion emissions has been a particularly beneficial advantage for live-cell imaging. However, the origin of this unique property has never been seriously investigated. We report, for the first time, the observation of stochastic photon emission (SPEM) in core/shell UCNPs (NaYF4:Yb3+,Er3+/NaYF4) on the microsecond and nanosecond time scales, even under continuous irradiation at 980 nm. This SPEM was attributed to slow upconversion cycles. We consider that the conventionally reported, nonblinking nature of UCNP emissions can be attributed to the averaging of SPEMs from multiple Er3+ ions and the low temporal resolution of previous observation. The off-time distribution, which possesses kinetics information for the upconversion pathways, was well fitted to a single exponential indicating involvement of a single rate-determining step. The distinct behaviors of the green and red emissions confirm their different photophysical pathways.</P>
Role of strangeness to the neutron star mass and cooling
Lee, Chang-Hwan,Lim, Yeunhwan,Hyun, Chang Ho,Kwak, Kyujin,Gwak, B.,Kang, G.,Kim, C.,Kim, H.-C.,Lee, C.-H.,Lee, J.,Lee, S.,Lee, W. EDP Sciences 2018 The European Physical Journal Conferences Vol.168 No.-
<P>Neutron star provides unique environments for the investigation of the physics of extreme dense matter beyond normal nuclear saturation density. In such high density environments, hadrons with strange quarks are expected to play very important role in stabilizing the system. Kaons and hyperons are the lowest mass states with strangeness among meson and bayron families, respectively. In this work, we investigate the role of kaons and hyperons to the neutron star mass, and discuss their role in the neutron star cooling.</P>
Kyujin Lee,HyoDuck Seo,Kyesan Lee 중소기업융합학회 2015 중소기업융합학회 국제학술대회논문집 Vol.2 No.1
In this paper, we propose the using Flexible Delivery Channel Selection (FDCS) to improve the QoS for MPEG4/SVC signal in MIMO-OFDM system. When we transmit the SVC signal, it has to consider the priority layer as base layer, and enhanced layer using adaptive channel selection. Especially, base layer has the higher priority, which takes through a good channel. In other hands, the enhanced layer has the lower priority, which takes through a worse channel. Because the priority of both layers are different, which are affected the video quality.
Kyujin Chang,Moran Ki,Eun Gyu Lee,Soon Young Lee,Byoungin Yoo,Jong Hyuk Choi 한국역학회 2015 Epidemiology and Health Vol.37 No.-
Most cases of Middle East Respiratory Syndrome (MERS) infection in Korea (outbreak: May 11-July 4, 2015) occurred in hospital settings, with uncertain transmission modes in some cases. We performed an in-depth investigation epidemiological survey on the 178th case to determine the precise mode of transmission. A 29- year-old man living in Pyeongtaek presented on June 16 with a febrile sensation, chills, and myalgia. Upon confirmatory diagnosis on June 23, he was treated in an isolation room and discharged on July 2 after cure. An epidemiological investigation of all possible infection routes indicated two likely modes of transmission: exposure to MERS in Pyeongtaek St. Mary’s Hospital during a visit to his hospitalized father (May 18-29), and infection through frequent contact with his father between the latter’s referral to Pyeongtaek Good Samaritan Bagae Hospital for treatment without confirmatory diagnosis until his death (May 29-June 6). Although lack of clear proof or evidence to the contrary does not allow a definitive conclusion, all other possibilities could be excluded by epidemiological inferences. While it is impossible to trace back the modes of transmission of all cases in a large-scale outbreak, case-by-case tracking and isolation of infected individuals and those in close contact with them is important in preventing the spread. Efforts should be made to establish a methodology for rapid tracking of all possible contacts and elimination-based identification of the precise modes of transmission.