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991.
Farzana Ahmad Muhammad Jamil Lee Jin Woo Young Jae Jeon 《Colloid and polymer science》2012,290(7):599-606
Acrylic polyethylene glycol(PEG)-based polymer-dispersed liquid crystal (PDLC) films have been fabricated to investigate the
effect of intermolecular interactions on PDLC performance. For this purpose, the amphiphilic liquid crystal and polymers are
selected as PDLC composite materials. The acrylic PEG contents are varied from 0 to 66.66 mol wt.% in order to understand
the effects of different levels of additions on the microstructure and electro-optical properties of the PDLC films. For this
intention, polarized optical microscopy and UV–vis spectroscopy are used. The extent of phase separation and anchoring energy
are also examined using Fourier transform infrared (FTIR) spectroscopy and contact angle measurements in consequence of acrylic
PEG addition. The contrast ratio, threshold voltage, as well as saturation voltage, tended to increase with the addition of
acrylic PEG. The molecular affinity involved in the polymer matrix and LC molecules affected the phase separation which is
responsible for the formation of domain size; this accordingly changed the electro-optical properties of PDLC film. 相似文献
992.
Huyen Thanh Vo Young Jin Kim Eun Hee Jeon Dr. Chang Soo Kim Prof. Hoon Sik Kim Dr. Hyunjoo Lee 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(29):9019-9023
A new type of water‐soluble ionic cellulose was obtained by means of the dissolution of cellulose in dimethylimidazolium methylphosphite at elevated temperatures over 120 °C. FTIR spectroscopy, 1H and 13C NMR spectroscopy, and elemental analysis results revealed that the repeating unit of the water‐soluble cellulose consists of a dialkylimidazolium cation and a phosphite anion bonded to cellulose. The degree of phosphorylation on the cellulose chain was between 0.4 and 1.3 depending on the reaction temperature and time. With an increasing degree of phosphorylation, water solubility was increased. Scanning electron microscopy and X‐ray diffraction analyses revealed that the cellulose crystalline phase in the parent crystalline cellulose changed to an amorphous phase upon transformation into ionic cellulose. Thermogravimetric analysis showed the prepared phosphorylated cellulose was stable over 250 °C and a substantial amount of residue remained at 500 °C. 相似文献
993.
Ju Hyun Park Hee‐Dong Kim Seok Man Hong Min Ju Yun Dong Su Jeon Tae Geun Kim 《固体物理学:研究快报》2014,8(3):239-242
The improvement of resistive switching (RS) phenomena of silicon‐nitride (SiNx)‐based resistive random access memory (ReRAM) cells through oxygen doping process was investigated. As a result, compared to un‐doped SiNx films, the oxygen doped SiNx (SiNx:O2)‐based ReRAM cells show a lower current (~0.3 μA) level at a high resistance state and a smaller variation of operating voltage through the reduction of leakage current in the SiNx:O2 film by combining silicon dangling bonds and doped oxygen ions. Therefore, we believe that the oxygen doping process in SiNx films can effectively improve the RS characteristics of SiNx‐based ReRAM cells. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
994.
Wonsang Koh Ji Ii Choi Euigyung Jeong Seung Geol Lee Seung Soon Jang 《Current Applied Physics》2014,14(12):1748-1754
In this study, we investigate Li adsorption mechanisms on the C60-SWCNT hybrid system using density functional theory. It is found that the Li adsorption energy of the C60-SWCNT hybrid system is increased in comparison to that of the pure SWCNT. The Li adsorption energy ranges from −1.917 eV to −2.642 eV for the single-Li adsorbed system and from −2.351 eV to −2.636 eV for the double-Li adsorbed system. It is also found that the adsorption energy becomes similar at most positions throughout the structure. In addition, the Li adsorption energy of 31-Li system is calculated to be −1.863 eV, which is significantly lower than the Li–Li binding energy (−1.030 eV). These results infer that Li atoms will be adsorbed on the space 1) between C60 and C60; 2) between SWCNT and C60; 3) the rest of the space (e.g. between SWCNTs), rather than form Li clusters. As more Li atoms are adsorbed onto the C60-SWCNT hybrid system due to such improved Li adsorption capability, the metallic character of the system is enhanced, which is confirmed via the band structure and electronic density of states. 相似文献
995.
Heewang Yang Byungsu Cho Joohyun Park Seokyoon Shin Giyul Ham Hyungtak Seo Hyeongtag Jeon 《Current Applied Physics》2014,14(12):1767-1770
We reported the effects on the electrical behavior of amorphous indium–gallium–zinc oxide (a-IGZO) thin film transistors (TFTs) after introducing various positions and sizes of Au nanoparticles (NPs) in the channel layer. These TFTs showed an off-current increase and threshold voltage (Vth) shift compared to conventional a-IGZO TFTs. The effects of Au NPs are explained to form the carrier conduction path which causes the current leakage in the channel layer, and act as either electron injection sites or trap sites. Therefore, this study demonstrates that the optimized control of size and position of Au NPs in the channel layer is crucial for its application in the electrical stability improvement and Vth control of a-IGZO TFTs. 相似文献
996.
Dinesh Kumar Rayabarapu Aihua Zhou Kyu Ok Jeon Thiwanka Samarakoon Alan Rolfe Hina Siddiqui Paul R. Hanson 《Tetrahedron》2009,65(16):3180-7773
The development of new methods to skeletally diverse sultams based on a central α-halo benzene sulfonamide building block is reported. Several salient features of this building block are utilized in multiple reaction pathways, including the Heck reaction, C- and O-arylation, Sonogashira-Pauson-Khand, Sonogashira-intramolecular hydroamination, and domino aza-Michael-Heck for the generation of five-, six-, and seven-membered benzofused bicyclic and tricyclic sultams. 相似文献
997.
Kyu Ok Jeon Dinesh Rayabarapu Alan Rolfe Kelly Volp Iman Omar Paul R. Hanson 《Tetrahedron》2009,65(26):4992-7773
The development of a ring-opening metathesis/ring-closing metathesis/cross-metathesis (ROM-RCM-CM) cascade strategy to the synthesis of a diverse collection of bi- and tricyclic sultams is reported. In this study, functionalized sultam scaffolds derived from intramolecular Diels-Alder (IMDA) reactions undergo metathesis cascades to yield a collection of tricyclic sultams. Additional appendage-based diversity was achieved by utilizing a variety of CM partners. 相似文献
998.
This paper presents a rapid and quantitative radiochemical separation method for the Pu, Am and Cm isotopes with an anion
exchange resin and a TRU resin. After the Pu isotopes were purified with an anion exchange resin method and the Am and Cm
isotopes were purified with the TRU resin method, micro-coprecipitation method was applied for an alpha-source preparation.
The activity concentrations and activity ratios for the Pu, Am and Cm isotopes in a radioactive sample were measured by radiation
counting methods such as an alpha-spectrometry and a liquid scintillation counting as well as by a mass spectroscopic method
such as a thermal ionization mass spectrometry. 相似文献
999.
1000.
Rizwan Wahab S.G. Ansari Hyung-Kee Seo Young Soon Kim Eun-Kyung Suh Hyung-Shik Shin 《Solid State Sciences》2009,11(2):439-443
Rosette-like structures of ZnO were synthesized at low temperature (60 °C) using solution process over 20 min of time. Hydroxylamine hydrochloride was used as capping agent with zinc nitrate hexahydrate and sodium hydroxide. Transition from triangular shaped plate like particles to rosette-like structure and to individual nanorods is observed with increasing refluxing temperature. Single-crystalline nature with wurtzite hexagonal phase is confirmed from transmission electron microscopic observations. Photoelectron spectroscopic measurement presented spectra close to the standard bulk ZnO, with an O 1s peak composed of surface adsorbed O–H group, O2? in the oxygen vacancies on ZnO structure and ZnO. 相似文献