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81.
82.
Tae Jin Park Sung Jin Park Dae Hyun Kim In Soo Kim Soo Kyung Kim Se Young Choi 《Current Applied Physics》2008,8(6):716-719
Optical switching and structural transformation of GeTe–Sb2Te3 pseudobinary alloys, Ge2Sb2Te5, Ge1Sb2Te4, and Ge1Sb4Te7, were studied for data storage application. As-deposited Ge2Sb2Te5, Ge1Sb2Te4, and Ge1Sb4Te7 thin films were amorphous and they crystallized to FCC and HCP upon heat treatment. Crystallization was accelerated by increasing the proportion of Sb2Te3 rather than GeTe in Ge–Sb–Te compounds; this was observed by reflectivity changes under nanosecond laser irradiation in static tester. The different crystallization kinetics according to composition might be affected by the structural incompatibility of GeTe under the ‘Umbrella Flip’ theory. 相似文献
83.
The synthetic route of unsubstituted polythiophene (PT) nanoparticles was investigated in aqueous dispersion via Fe3+-catalyzed oxidative polymerization. With this new synthetic method, high conversion of thiophene monomers was obtained with only a trace of FeCl3. The dispersion state showed that the PT nanoparticles were well dispersed in many polar solvents, compared to non-polar solvents, such as acetone, chloroform, hexane, and ethyl acetate. To compare the photoluminescence properties between PT nanoparticle dispersion and PT bulk polymers, the PL intensities were measured in the same measuring conditions. Further, core–shell poly(styrene/thiophene) (poly(St/Th)) latex particles were successfully prepared by Fe3+-catalyzed oxidative polymerization during emulsifier-free emulsion polymerization. The different polymerization rates of each monomer resulted in core–shell structure of the poly(St/Th) latex particles. The PL data of the only crumpled shells gave evidence that the shell component of core–shell poly(St/Th) latex particles is indeed PT, which was corroborated by SEM data. PL intensity of the core–shell poly(St/Th) nanoparticle dispersion was much higher than that of the PT nanoparticle dispersion, due to its thin shell layer morphology, which was explained by the self-absorption effect. 相似文献
84.
Hyun Lee Dong Hun Lee Takeshi Kanashima Masanori Okuyama 《Applied Surface Science》2008,254(21):6932-6936
Chemical reactivity of fluorine molecule (F2)-germanium (Ge) surface and dissociation of fluorine (F)-Ge bonding have been simulated by semi-empirical molecular orbital method theoretically, which shows that F on Ge surface is more stable compared to hydrogen. Ge MIS (metal insulator semiconductor) capacitor has been fabricated by using F2-treated Ge(1 0 0) substrate and HfO2 film deposited by photo-assisted MOCVD. Interface state density observed as a hump in the C-V curve of HfO2/Ge gate stack and its C-V hysteresis were decreased by F2-treatment of Ge surface. XPS (X-ray photoelectron spectroscopy) depth profiling reveals that interfacial layer between HfO2 and Ge is sub-oxide layer (GeOx or HfGeOx), which is believed to be origin of interface state density.F was incorporated into interfacial layer easily by using F2-treated Ge substrate. These results suggest that interface defect of HfO2/Ge gate stack structure could be passivated by F effectively. 相似文献
85.
Electron injection behavior of lithium quinolate (Liq)/Ca/Al cathode was investigated by using X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy (UPS). Interfacial energy barrier lowering of Liq/Ca/Al cathode was dependent on Ca thickness and maximum energy level shift was observed at a Ca thickness of 1 nm. Maximum current density could be obtained in Liq/Ca/Al device at a Ca thickness of 1 nm and it was well correlated with energy level shift from UPS measurement. Power efficiency of Liq/Al device could be improved by more than 70% by inserting Ca layer between Liq and Al. 相似文献
86.
Hyunwoo Choi Yunseok Kim Seungbum Hong Tae‐Hyun Sung Hyunjung Shin Kwangsoo No 《固体物理学:研究快报》2011,5(8):289-291
We observed the nanoscale retention dynamics of polycrystalline PbTiO3 nanotubes using piezoresponse force microscopy. We found that the retention loss of the nanodot domains on the nanotubes showed the stretched exponential relaxation behaviors with stretched exponential factor n being less than 1 (0.523 and 0.692), which are similar to the thin films. In addition, the nanodot domains showed a diverse relaxation time constant τ due to different remnant polarization of each dot domains. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
87.
S. Sambasivam D. Paul Joseph Jung Hyun Jeong Byung Chun Choi Kwon Taek Lim Sang Su Kim Tae Kwon Song 《Journal of nanoparticle research》2011,13(10):4623-4630
Diluted magnetic semiconductor (DMS) nanoparticles of Sn1−x
Er
x
O2 (x = 0.0, 0.02, 0.04, and 0.1) were prepared by sol–gel method. The X-ray diffraction patterns showed SnO2 rutile structure for all samples with no impurity peaks. The decrease in crystallite size with Er concentration was confirmed
from TEM measurements (from 12 to 4 nm). The UV–Visible absorption spectra of Er-doped SnO2 nanoparticles showed blue shift in band gap compared to undoped SnO2. The electron spin resonance analysis of Er-doped SnO2 nanoparticles indicate Er3+ in a rutile lattice and also decrease in intensity with Er concentration above x = 0.02. Temperature-dependent magnetization studies and the inverse susceptibility curves indicated increased antiferromagnetic
interaction with Er concentration. 相似文献
88.
Dokyung Yoon Daekwang Woo Jung Heon Kim Moon Ki Kim Taesung Kim Eung-Soo Hwang Seunghyun Baik 《Journal of nanoparticle research》2011,13(6):2543-2551
The cytotoxicity of alumina nanoparticles (NPs) was investigated for a wide range of concentration (25–200 μg/mL) and incubation time (0–72 h) using floating cells (THP-1) and adherent cells (J774A.1, A549, and 293). Alumina NPs were gradually agglomerated over time although a significant portion of sedimentation occurred at the early stage within 6 h. A decrease of the viability was found in floating (THP-1) and adherent (J774A.1 and A549) cells in a dose-dependent manner. However, the time-dependent decrease in cell viability was observed only in adherent cells (J774A.1 and A549), which is predominantly related with the sedimentation of alumina NPs in cell culture medium. The uptake of alumina NPs in macrophages and an increased cell-to-cell adhesion in adherent cells were observed. There was no significant change in the viability of 293 cells. This in vitro test suggests that the agglomeration and sedimentation of alumina NPs affected cellular viability depending on cell types such as monocytes (THP-1), macrophages (J774A.1), lung carcinoma cells (A549), and embryonic kidney cells (293). 相似文献
89.
Hyun Seok Yang 《The European Physical Journal C - Particles and Fields》2009,64(3):445-457
We map noncommutative (NC) U(1) gauge theory on ℝ
C
d
×ℝ
NC
2n
to U(N→∞) Yang–Mills theory on ℝ
C
d
, where ℝ
C
d
is a d-dimensional commutative spacetime while ℝ
NC
2n
is a 2n-dimensional NC space. The resulting U(N) Yang–Mills theory on ℝ
C
d
is equivalent to that obtained by the dimensional reduction of (d+2n)-dimensional U(N) Yang–Mills theory onto ℝ
C
d
. We show that the gauge-Higgs system (A
μ
,Φ
a
) in the U(N→∞) Yang–Mills theory on ℝ
C
d
leads to an emergent geometry in the (d+2n)-dimensional spacetime whose metric was determined by Ward a long time ago. In particular, the 10-dimensional gravity for
d=4 and n=3 corresponds to the emergent geometry arising from the 4-dimensional N=4{\mathcal{N}}=4 vector multiplet in the AdS/CFT duality. We further elucidate the emergent gravity by showing that the gauge-Higgs system
(A
μ
,Φ
a
) in half-BPS configurations describes self-dual Einstein gravity. 相似文献
90.
Li J Adachi I Aihara H Arinstein K Asner DM Aulchenko V Aushev T Bakich AM Bhardwaj V Bhuyan B Bischofberger M Bondar A Bozek A Bračko M Brovchenko O Browder TE Chang MC Chen A Chen P Cheon BG Chistov R Cho K Choi SK Choi Y Dalseno J Doležal Z Drutskoy A Eidelman S Esen S Fast JE Gaur V Garmash A Goh YM Haba J Hara T Hayasaka K Hayashii H Horii Y Hoshi Y Hou WS Hsiung YB Hyun HJ Iijima T Inami K Ishikawa A Itoh R Iwabuchi M Iwasaki Y Iwashita T Julius T Kang JH Kapusta P Katayama N Kawasaki T 《Physical review letters》2012,108(18):181808
We report first observations of B(s)(0) → J/ψη and B(s)(0) → J/ψη'. The results are obtained from 121.4 fb(-1) of data collected at the Υ(5S) resonance with the Belle detector at the KEKB e+ e- collider. We obtain the branching fractions B(B(s)(0) → J/ψη)=[5.10±0.50(stat)±0.25(syst)(-0.79)(+1.14)(N(B(s)(*) B(s)(*))]×10(-4), and B(B(s)(0) → J/ψη')=[3.71±0.61(stat)±0.18(syst)(-0.57)(+0.83)(N(B(s)(*) B(s)(*))]×10(-4). The ratio of the two branching fractions is measured to be (B(B(s) → J/ψη'))/(B(B(s) → J/ψη))=0.73±0.14(stat)±0.02(syst). 相似文献