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991.
J.H.?SongEmail author Y.Z.?Yoo T.?Chikyow H.?Koinuma 《Applied Physics A: Materials Science & Processing》2004,79(3):457-460
Epitaxial growth of non-polar wurtzite (11-20) AlN thin films was achieved on a Si(100) substrate by inserting an MnS buffer layer. The a-plane AlN film and MnS buffer layer were fabricated by pulsed KrF excimer laser deposition, and their micro- and interfacial atomic structures were investigated by transmission electron microscopy. The epitaxial relationship between films and substrate was found to be AlN(11-20)MnS(100)Si(100) with in-plane alignment of AlN[1-101]MnS[011]Si[011]. AlN[11-20] grown on Si is perpendicular to AlN[0001] and parallel to MnS[100]. The MnS/Si interface is abrupt enough to inherit the orientation of the Si(100) surface. A sharp interface was also observed for AlN/MnS without any intermediate layer. PACS 81.05.Ea; 81.05.Zx; 81.15.Fg; 68.37.Lp 相似文献
992.
A high-definition analysis based on flow topology is made on the vortex motions under natural and lock-on conditions in the
near-wake region of a circular cylinder, where two-dimensional flow fields in the wake-transition regime are measured by a
time-resolved PIV system. The Reynolds stress distributions are examined in view of the mean separation streamline and the
trajectory ofthe vortex center. It is shown that, by the lock-on, the Reynolds stresses become stronger and their dispositions
match well with the shortened wake bubble, indicating perfect synchronization of shedding to the oscillatory forcing flow
in the near field, which causes increased lift and drag forces. 相似文献
993.
994.
Self-assembled arrays of zinc oxide nanoparticles from monolayer films of diblock copolymer micelles 总被引:1,自引:0,他引:1
A hexagonal array of optically active ZnO nanoparticles was synthesized in situ on the solid substrate by utilizing a single-layered film of diblock copolymer micelles as a nanostructured template. 相似文献
995.
996.
997.
Jeong Chul Lee Viresh Dutta Jinsu Yoo Junsin Yi Jinsoo Song Kyung Hoon Yoon 《Superlattices and Microstructures》2007,42(1-6):369
Superstrate p-i-n amorphous silicon thin-film (a-Si:H) solar cells are prepared on SnO2:F and ZnO:Al transparent conducting oxides (TCOs) in order to see the effect of TCO/p-layers on a-Si:H solar cell operation. The solar cells prepared on textured ZnO:Al have higher open circuit voltage Voc than cells prepared on SnO2:F. The presence of a thin microcrystalline p-type silicon layer (μc-Si:H) between ZnO:Al and p a-SiC:H plays a major role by causing an improvement in the fill factor as well as in Voc of a-Si:H solar cells prepared on ZnO:Al TCO. Without any treatment of the p-i interface, we could obtain a high Voc of 994 mV while keeping the fill factor (72.7%) and short circuit current density Jsc at the same level as for the cells on SnO2:F TCO. This high Voc value can be attributed to modification in the current transport in this region due to creation of a potential barrier. 相似文献
998.
TiO2 thin film was deposited on non-heated Si(1 0 0) substrate by RF magnetron sputtering. The as-deposited films were annealed by a conventional thermal annealing (CTA) and rapid thermal annealing (RTA) at 700 and 800 °C, and the effects of annealing temperature and method on optical properties of studied films were investigated by measuring the optical band gaps and FT-IR spectra. And we also compared the XRD patterns of the studied samples. The as-deposited film showed a mixed structure of anatase and brookite. Only rutile structures were found in samples annealed above 800 °C by CTA, while there are no special peaks except the weak brookite B(2 3 2) peak for the sample annealed at (or above) 800 °C by RTA. FT-IR spectra show the broad peaks due to Ti-O vibration mode in the range of 590-620 cm−1 for the as-deposited film as well as samples annealed by both annealing methods at 700 °C. The studied samples all had the peaks from Si-O vibration mode, which seemed to be due to the reaction between TiO2 and Si substrate, and the intensities of these peaks increased with increasing of annealing temperature. The optical band gap of the as-deposited film was 3.29 eV but it varied from 3.39 to 3.43 eV as the annealing temperature increased from 700 to 800 °C in the samples annealed by CTA. However, it varied from 3.38 to 3.32 eV as the annealing temperature increased from 700 to 800 °C by RTA. 相似文献
999.
1000.
Park HG Kim MJ Park MK Jung HJ Lee J Choi SH Lee YJ Jeong BS Lee JH Yoo MS Ku JM Jew SS 《The Journal of organic chemistry》2005,70(5):1904-1906
A new Merrifield-resin-derived glycinimine tert-butyl ester (9) was prepared and applied to the enantioselective synthesis of non-natural alpha-amino acids. High enantioselectivities (86 to >99% ee) were accomplished by employing the aldimine linker under phase-transfer alkylation conditions, using 50% aqueous CsOH in toluene/chloroform (7:3) at 0 degrees C in the presence of N-(9-anthracenylmethyl)-O(9)-allylcinchonidium bromide (10 mol %). 相似文献