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Andreas Richter Ken-ichi Matsuda Tatsushi Akazaki Tadashi Saku Hiroyuki Tamura Yoshiro Hirayama Hideaki Takayanagi 《Physica E: Low-dimensional Systems and Nanostructures》2005,25(4):472-478
We present studies on the electric transport in a lateral GaAs/AlGaAs quantum dot defined by a patterned single connected metallic front-gate. This gate design allows to easily couple a large number of quantum dots and therefore holds high potential in the design of new materials with tailor-made band structures based on quantum dot superlattices of controlled shape. Clear Coulomb diamond structures and well pronounced tunneling peaks observed in experiment indicate that single-electron control has been achieved. However, the dependence on electron density in the heterostructure embedding the dot, which is controlled by an additional back-gate, reveals that transport characteristics are strongly influenced supposedly by potential fluctuations in the dot and lead regions. 相似文献
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Toshikazu Kaise Hiroshi Yamauchi Yoshiya Horiguchi Takayuki Tani Shigenobu Watanabe Teruhisa Hirayama Shozo Fukui 《应用有机金属化学》1989,3(3):273-277
The acute toxicity of methylarsonic acid, CH3AsO(OH)2 (MAA), dimethylarsininc acid, (CH3)2AsO(OH) (DMAA), and trimethylarsine oxide, (CH3)3AsO (TMAO), were examined in mice with oral administration. The LD50 values of MAA, DMAA and TMAO were 1.8, 1.2 and 10.6 g kg?1 respectively. The toxicity of MAA and DMAA was very much lower than that for inorganic arsenic compounds. It was shown that TMAO has a similar acute toxicity to arsenobetaine. On the other hand, when the mice were administered 14.4 g kg?1 of TMAO once only orally, a garlic-like odor (trimethylarsine, (CH3)3As) was definitely detectable in the exhalation of the animals by the human olfactory sense within about a few minutes. 相似文献
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A novel synergistic extraction system was investigated for the possible selective separation of light lanthanoids using an ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, as an extraction solvent and 2-thenoyltrifluoroacetone and 18-crown-6 as extractants. Trivalent lanthanum was efficiently extracted as a cationic ternary complex by the cation-exchange process, whereas europium and lutetium showed relatively low extractability without forming respective ternary complexes. This result is thought to originate in a size-fitting effect of 18-crown-6 to lanthanum and the unique nature of the ionic liquid as a chelate extraction solvent. 相似文献
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G. Dujardin L. Philippe M. Rose T. Hirayama M.J. Ramage G. Comtet L. Hellner 《Applied Physics A: Materials Science & Processing》1998,66(5):527-538
Received: 16 June 1997/Accepted: 26 October 1997 相似文献