排序方式: 共有59条查询结果,搜索用时 15 毫秒
31.
Fukuda T Kikukawa Y Tsuruya R Fuyuhiro A Ishikawa N Kobayashi N 《Inorganic chemistry》2011,50(22):11832-11837
A series of dialkoxy-substituted copper phthalocyanine (CuPc) precursors (4a-4d) have been prepared by treating phthalonitrile with the corresponding lithium alkoxide under mild conditions. The precursors exhibited high solubilities in common organic solvents, including acetone, toluene, tetrahydrofuran (THF), CH(2)Cl(2), and CHCl(3). Elongation of the alkoxy chains improved the solubilities of the precursors effectively, and accordingly, the butoxy-substituted derivative (4d) showed the highest solubility among 4a-4d. X-ray crystallography clarified that the conjugated skeletons of 4a-4d are all isostructural, and have two alkoxy groups in a syn-conformation fashion, leading to highly bent structures. Thermal conversions of the precursors examined by thermogravimetry (TG) and differential thermal analysis (DTA) demonstrate that 4a was converted into CuPc via two distinct exothermic processes in the 200-250 °C temperature range, while 4d exhibits only one exothermic signal in the DTA. In the field emission scanning electron microscopy (FESEM) images of 4a, the presence of two types of distinct crystal morphology (prismatic and plate-like crystals) can be recognized, implying that the two observed exothermic processes in the DTA can be attributed to the different crystal morphologies of the samples rather than the step-by-step elimination of the alkoxy groups. The thermal formation of CuPc from the precursors has been unambiguously confirmed by X-ray powder diffraction, UV-vis spectroscopy, and elemental analysis. The precursors were converted into CuPc at lower temperature with increasing chain length, presumably because of the increased void volume in the crystals. Thermal conversion performed in the solution phase results in a bright blue-colored solution with prominent absorption bands in the 650-700 nm region, strongly supporting the formation of CuPc. 相似文献
32.
Y. Naitou H. Ogiso S. Kamohara F. Yano A. Nishida 《Surface and interface analysis : SIA》2009,41(1):34-37
Carrier profiles within the near‐surface channel region of n‐type metal‐oxide‐semiconductor field‐effect transistors (n‐MOSFETs) have been examined using scanning capacitance microscopy (SCM). After the removal of a poly‐Si gate electrode, we were able to assess the qualitative local carrier concentration within specified regions of an n‐MOSFET using static capacitance (dC/dZ) measurement with its bias dependence (dC/dZ–V spectra). We found that the dC/dZ‐signal at the center of the channel region lowers as the gate length is reduced. This result is attributed to the carrier depletion within the channel, which is consistent with the threshold voltage (Vth) characteristics of the device properties. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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34.
Masafumi Tamura Hayato Ogata Yuu Ishida Yasunori Takahashi 《Tetrahedron letters》2017,58(40):3808-3813
Pd-catalyzed asymmetric 1,4-addition of phenylboronic acid to α,β-unsaturated carbonyl compounds was developed using chiral 1,10-phenanthroline derivative as ligand. Good yields (up to 97%), and high enantioselectivities (up to 97% ee) were achieved. 相似文献
35.
Yuu UCHIO Naoko SHIMA Kaho NAKAMURA Osamu NITTA Tetsuo IKAI 《Physical Therapy Research》2021,24(3):204
Objective: To clarify the corrected age of walking attainment in very low birth weight infants by birth weight and gestational age, and determine perinatal factors affecting the delay in walking attainment. Method: This was a longitudinal study. We investigated walking attainment and perinatal factors in 145 very low birth weight infants without neurological abnormalities (mean birth weight 1019.3 ± 299.7 g, gestational age 29.0 ± 2.9 weeks). The study infants were stratified by birth weight (group A: <1,000 g, group B: 1,000 g≤, <1,500 g) and gestational age (group I: <28 weeks, group II: 28 weeks≤, <37 weeks) and were compared using unpaired t-tests. Furthermore, we examined the perinatal factors that affect the delay in walking attainment using multiple regression analysis. Results: Of the walking attainment, infants in Group A were older than those in Group B (50th percentile, 15.8 vs. 14.7 months). Infants in Group I were older than those in Group II (50th percentile, 16.0 vs. 14.8 months). Using multiple regression analysis with walking attainment age as the dependent variable, the duration of mechanical ventilation was found to be significantly related. Conclusion: Very low birth weight infants with light weight and short gestational age have delayed walking attainment, and longer duration of mechanical ventilation increases the risk of delay. 相似文献
36.
Journal of Theoretical Probability - This paper concerns the density of the Hartman–Watson law. Yor (Z Wahrsch Verw Gebiete 53:71–95, 1980) obtained an integral formula that gives a... 相似文献
37.
Hirotsu M Shimizu Y Kuwamura N Tanaka R Kinoshita I Takada R Teki Y Hashimoto H 《Inorganic chemistry》2012,51(2):766-768
The reaction of manganese(II) acetate with a xanthene-bridged bis[3-(salicylideneamino)-1-propanol] ligand, H(4)L, afforded the tetramanganese(II,II,III,III) complex [Mn(4)(L)(2)(μ-OAc)(2)], which has an incomplete double-cubane structure. The corresponding reaction using manganese(II) chloride in the presence of a base gave the tetramanganese(III,III,III,III) complex [Mn(4)(L)(2)Cl(3)(μ(4)-Cl)(OH(2))], in which four Mn ions are bridged by a Cl(-) ion. A pair of L ligands has a propensity to incorporate four Mn ions, the arrangement and oxidation states of which are dependent on the coexistent anions. 相似文献
38.
Ito Y Tomiyasu Y Kawanabe T Uemura K Ushimizu Y Nishino H 《Organic & biomolecular chemistry》2011,9(5):1491-1507
Cyclophane-type macrocyclic compounds from 21 to 56 members having two fused dihydrofuran rings were synthesized by the manganese(III)-mediated oxidation of terminal dienes with bis(3-oxobutanoate)s containing aromatics. The reaction detail, characterization and reaction pathways are described. 相似文献
39.
Intra-board interconnection between optical waveguide channels is suitable for assembling high-speed optoelectronic printed
wiring boards (OE-PWB). Here, we propose a novel optical interconnection method combining techniques for both wavelength-based
optical waveguide addressing and plug-in optical waveguide alignment with a micro-hole array (MHA). This array was fabricated
by the mask transfer method. For waveguide addressing, we used a micro passive wavelength selector (MPWS) module, which is
a type of Littrow mount monochromator consisting of an optical diffraction grating, a focusing lens, and the MHA. From the
experimental results, we found that the wavelength addressing operation of the MPWS module was effective for intra-board optical
interconnection. 相似文献
40.
The presence of an adverse pressure gradient, shock/shock interaction and shock wave/boundary layer interaction often induces
flow separation around bodies. However, the effect of dissociated flow on separated flow characteristics, especially at hypersonic
speeds, is still not clear, and considerable differences are observed between experiments and numerical simulations. In this
investigation, the unsteady separated flow features around double cones are visualized in the Shock Wave Research Center (SWRC)
free-piston driven shock tunnel at a nominal Mach Number of 6.99 using multiple optical techniques. The time resolved shock
structure oscillations in the flow field around double cones (first cone, semi-apex angle = 25°; second cone, semi-apex angles=50°,
65°, 68° and 70°) have been visualized using a high-speed image converter camera (IMACON) at a nominal stagnation enthalpy
of 4.8 MJ/kg. In addition, flow visualization studies around the double cone is also carried out using Schlieren and double
exposure holographic interferometry in order to precisely locate the separation point and measure the separation length. The
presence of a triple shock structure in front of the second cone and a non-linear unsteady shock structure oscillation in
the flow field are the significant results from visualization studies on the 25° /65°, 25° /68° and 25°/70° double cones.
On the other hand, the flow field around 25° /50° is relatively steady and Type V shock/shock interaction is observed. Illustrative
numerical simulation studies are carried out by solving N-S equations to complement the experiments. The simulated flow features
around a double cone agree well qualitatively with experiments. 相似文献