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991.
992.
Hirotaka Sato Takuya Yamaguchi Tetsuhiko Isobe Shuichi Shoji Takayuki Homma 《Electrochemistry communications》2010,12(6):765-768
An approach to control the diameter of high-aspect-ratio pores formed into a silicon wafer by an electrochemical etching process is reported. Hole (h+) was involved in the etching reaction and the collection of the h+ was the key factor. Artificial micro-cavities were fabricated on the silicon surface prior to the etching. The depth of the space charge region (SCR), Schottky barrier on the silicon-electrolyte interface, was adjusted regarding the depth of the micro-cavities by applied overpotential and specific resistance of the silicon wafer. The collection of h+ at the tip of the cavity site was widely controlled by the adjusted SCR. Consequently the electrochemically etched domain at the cavity site was actively tuned, and then high-aspect-ratio pore with the controlled diameter was formed. The diameter was tuned by the SCR depth which was controlled by the overpotential and the specific resistance. The diameter tuning mechanism worked under the mask-free condition. 相似文献
993.
R. Nomura M. Suzuki M. Yamaguchi Y. Sasaki T. Mizusaki 《Physica B: Condensed Matter》2000,280(1-4):140-141
The sound velocity of a single-domain 3He crystal was measured in the nuclear-ordered low-field phase and the paramagnetic phase along the melting curve, using 10.98 MHz longitudinal sound. The temperature dependence of the sound velocity along the melting curve was explained by a nuclear spin contribution and the molar volume change along the melting curve. By comparing the measured velocity with thermodynamic quantities, we extracted the Grüneizen constant for the exchange energy. The anisotropy of the velocity in the ordered phase was investigated for three samples and was found to be smaller than 2×10−5 in Δv/v. The attenuation coefficient of the sound was much smaller than 0.2 cm−1. 相似文献
994.
Masashi Shiotsuki Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2014,52(10):1392-1400
The eight‐membered cyclic monomer, prepared by Diels–Alder reaction of 1,5‐cyclooctadiene and anthracene, polymerized via Ru‐catalyzed ring‐opening metathesis to efficiently afford high polymers (Mn up to 631,000). Unsaturated moieties in the main chain of the obtained polymer were hydrogenated with a homogeneous ruthenium catalyst in quantitative conversion, confirmed by 1H‐NMR measurement. The self‐standing membranes were provided by casting the tetrahydrofuran solutions of both nonhydrogenated and hydrogenated polymers. The obtained membranes showed high transparency in the region of >300 nm with mechanical flexibility. Thermal gravimetric analysis revealed that both nonhydrogenated and hydrogenated polymers decomposed in two stages. The first‐stage decomposition starting at around 230 °C was caused by retro Diels–Alder reaction forming anthracene, proven by pyrolysis gas chromatography mass spectroscopy (GC‐MS) analyses. Mechanical grinding of the polymers induced the formation of anthracene in solid state, which transformed the polymer into blue‐luminescent materials under UV irradiation. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1392–1400 相似文献
995.
The titled compound is easily obtained by palladium (II)-catalyzed bromoallylation of ethynyltrimethylsilane and can serve as 4-pentenoyl anion equivalent which is a valuable synthetic grouping. 相似文献
996.
997.
Tsuneo Imamoto Ken Tamura Tomokazu Ogura Yui Ikematsu Daisuke Mayama Masashi Sugiya 《Tetrahedron: Asymmetry》2010,21(11-12):1522-1528
Improved methods for the preparation of methylene-bridged diphosphine ligands are described. Both enantiomers of the key intermediate tert-butylmethylphosphine–borane were prepared via resolution or by the conversion of one enantiomer into the opposite enantiomer. The precursor borane complexes of bis(tert-butylmethylphosphino)methane (t-Bu-MiniPHOS), bis((1,1,3,3-tetramethylbutyl)methylphosphino)methane (t-Oct-MiniPHOS), and (tert-butylmethylphosphino)(di-tert-butylphosphino)methane (trichickenfootphos) were prepared in good yields and enantiopure form. 相似文献
998.
999.
Masashi HAYAKAWA Alexander SCHEKOTOV Stelios POTIRAKIS Kostas EFTAXIAS 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2015,91(1):25-30
The criticality of ULF (Ultra-low-frequency) magnetic variations is investigated for the 2011 March 11 Tohoku earthquake (EQ) by natural time analysis. For this attempt, some ULF parameters were considered: (1) Fh (horizontal magnetic field), (2) Fz (vertical magnetic field), and (3) Dh (inverse of horizontal magnetic field). The first two parameters refer to the ULF radiation, while the last parameter refers to another ULF effect of ionospheric signature. Nighttime (L.T. = 3 am ± 2 hours) data at Kakioka (KAK) were used, and the power of each quantity at a particular frequency band of 0.03–0.05 Hz was averaged for nighttime hours. The analysis results indicate that Fh fulfilled all criticality conditions on March 3–5, 2011, and that the additional parameter, Dh reached also a criticality on March 6 or 7. In conclusion, criticality has reached in the pre-EQ fracture region a few days to one week before the main shock of the Tohoku EQ. 相似文献
1000.
Hirosato Yamazaki Akinori Shouji Masashi Kajita Masayuki Yagi 《Coordination chemistry reviews》2010,254(21-22):2483-2491
The construction of an artificial photosynthetic device requires detailed understanding of the catalytic aspects of photo- or photoelectro-driven water oxidation. This has been attracting much interest as one of the promising clean energy-providing systems for the future. This review mainly covers progress on electrocatalytic and photocatalytic systems for water oxidation in the last decade. It includes conventional iridium oxide colloid catalysts and the new electrodeposited cobalt-phosphate catalyst films for water oxidation. 相似文献