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121.
Takaaki Horaguchi Kazuhiro Miyazawa Eietsu Hasegawa Takahachi Shimizu Tsuneo Suzuki Kiyoshi Tanemura 《Journal of heterocyclic chemistry》1990,27(4):941-948
A variety of 2,5-dioxacyclohepta[jkl]-as-indacenes 5, 7–14 were synthesized as a new heterocycle by the treatment of diethyl (5,9-dioxobenzocyclohepten-1,4-diyloxy)diacetates 4a-e with potassium hydroxide or sodium hydride in dioxane. The mechanism of furan-ring formation from 4a-e was discussed. 相似文献
122.
Ken Okada Miyako Akiyoshi Atsumi Miyake Terushige Ogawa Mitsuo Nomura Takehiro Matsunaga 《Journal of Thermal Analysis and Calorimetry》2009,97(2):769-774
On January 21, 2003, an explosion occurred while ion exchange resin (IER) was being used to separate impurities from uranium
solution. To clarify the cause of the accident and go/no-go criteria of the explosion, elemental analysis of the IER, DSC
analysis, and SIKAREX analysis (a screening tool for runaway reactions) were performed. Finally, experiments on the same scale
as the accident were conducted in an explosion chamber. When HClO4 was added to IER-NO3, the IER violently exploded without any heating nor metal ions such as uranium. It was confirmed that the accident was caused
by an incorrect procedure in the chemical process. From the standpoint of explosion safety, IER-NO3 in particular should be kept away from perchloric acid in the laboratory. 相似文献
123.
Poly(2-vinylpyridine) or poly(4-vinylpyridine) coated on a piezoelectric quartz crystal adsorbed copper, thus decreasing the oscillation frequency. The bound copper could be removed by EDTA solution. Poly(4-vinylpyridine) is recommended to determine copper (5–35 μM) in a maleate buffer at pH 6.6 flowing over the coated crystal for 5 min. Iron(III) and cadmium interfered. 相似文献
124.
The diffusion of protons in porous media was observed and evaluated using a pH-imaging microscope with a flat semiconductor. Small particles were packed on the sensing surface of the flat sensor, followed by the addition of a lactic acid droplet on the top of the packed particle layer. The pH distribution accompanied by the diffusion of lactic acid was visualized at the bottom of the layer using the flat sensor. The difference in the diffusion property was confirmed depending on the particle type. The effective diffusion coefficients of the lactic acid in some porous media were estimated by combining the experimental results and mathematical calculation. 相似文献
125.
We confirmed that the light intensity (λ=785 nm) scattered from an isolated hemispherical Au nanoparticle was resonantly enhanced
at a diameter of 200 nm and a height of 50 nm, as observed experimentally using a collection-mode near-field optical microscope.
The experimental results agreed with the calculated results using Mie’s theory. Furthermore, we observed resonant energy transfer
of the optical near-field energy along a chain of Au nanoparticles. The magnitude of the transferred energy increased resonantly
at the size of resonant light scattering for an isolated Au nanoparticle (200 nm diameter with 240 nm center-to-center separation).
PACS 42.82.Et; 73.20.Mf; 78.67.Bf 相似文献
126.
Treatment of 1,6-dialkylhexa-1,5-diene-3,4-diones with bis(iodozincio)methane gave zinc alkoxides of cis-5,6-dialkylcyclohepta-3,7-diene-1,3-diol in good yields at room temperature. The reaction proceeded with high stereospecificity. Bis(iodozincio)methane converted the diketone into the cis-divinylcyclopropane-1,2-diol stereoselectively; this diol transformed into the corresponding cycloheptane derivative stereospecifically via Cope rearrangement. 相似文献
127.
Mitsushiro Nomura Shigemi Kondo Eriko Suzuki Glenn V. Alea Chikako Fujita-Takayama Masatsugu Kajitani 《Journal of organometallic chemistry》2010,695(21):2366-2895
Eight new sulfur-rich [CpCo(dithiolene)] complexes were synthesized from [Zn(dmit)2]2− as a starting material. The structures, electrochemical behavior and electronic absorption spectra of the sulfur-rich [CpCo(S2C2S2Y)] complexes could be compared with the early data of analogous Ni complexes. [CpCo(pddt)] (Y = -(CH2)3-), [CpCo(dpdt)] (Y = -CH2C(CH2)CH2-), [CpCo(bddt)] (Y = -(CH2)4-), [CpCo(dtdt)] (Y = -CH2SCH2-) and [CpCo(poddt)] (Y = -CH2C(O)CH2-) crystallized in all isostructural with the corresponding paramagnetic [CpNi(dithiolene)] complexes, but [CpCo(dmid)] (Y = CO), [CpCo(dddt)] (Y = -(CH2)2-) and [CpCo(F2pddt)] (Y = -CH2CF2CH2-) crystallized in non-isostructural with them. These molecules are associated with intermolecular short S?S contacts in the crystals. [CpCo(F2pddt)] did not show any remarkable S?S contacts but indicated interesting fluorine segregation and Cp?Cp face-to-face interactions. Redox potentials of [CpCo(dithiolene)] complexes were obtained with the cyclic voltammetry measurements and dimerized by electrochemical oxidations. Electronic absorption spectra of [CpCo(dithiolene)] complexes showed visible absorption in the range of 585-701 nm as lowest energy wavelengths (? = 9800-11,800 M−1 cm−1) in solutions, and they were higher energy than those of [CpNi(dithiolene)] complexes (near-IR). 相似文献
128.
Yoshida K Fujikawa T Watanabe Y 《The Journal of the Acoustical Society of America》2011,130(1):135-144
The direction of the secondary Bjerknes force between a free bubble and an attached bubble was experimentally investigated. The behavior of the two bubbles in an ultrasonic standing wave of 27 kHz was observed using an imaging system with a high-speed video camera. It was demonstrated experimentally that the direction of the force reversed at a specific separation distance between the two bubbles, which was defined as the threshold distance. The threshold distance changed with the radius of the attached bubble. In addition, a theoretical calculation was performed using a previously derived model that coupled the vibrations of two free bubbles [Ida, Phys. Lett. A 297, 210-217 (2002)]. The experiment data for the threshold distance qualitatively agreed with the theoretical predictions, except when the separation distance was very small. Then, it was discovered that the free bubble became trapped near the attached bubble when the separation distance between the two bubbles was very small. This indicated that a stable equilibrium point for the separation distance exists that cannot be predicted by the theoretical model. 相似文献
129.
K. Süvegh K. Nomura G. Juhsz Z. Homonnay A. Vrtes 《Radiation Physics and Chemistry》2000,58(5-6):733-736
The CO2 absorption of several ABO3 type perovskites was studied by positron lifetime spectroscopy. The longer positron lifetime was associated with positrons trapped by A site vacancies. The evaluated positron lifetime data indicated the relative stability of the crystal structure of Sr(Co0.5Fe0.5)O3−δ against Ca doping at low Ca concentrations. Oxygen desorption and CO2 absorption/desorption could also be followed by positron lifetime spectroscopy. It was shown that the concentration of oxygen vacancies has a large effect on positron lifetime data through the electron density of A site vacancies. 相似文献
130.
Palladium nanoparticles stabilized by a polyion complex composed of poly{4-chloromethylstyrene-co-(4-vinylbenzyl) tributylammonium chloride} and poly(acrylic acid) were easily recovered by filtration after pH treatment. The polyion complex stabilized palladium nanoparticles have high catalytic activity for the Suzuki and Heck reactions in water. 相似文献