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91.
Jiraporn Klanwan Takafumi Seto Takuma Furukawa Yoshio Otani Tawatchai Charinpanitkul Masamichi Kohno Makoto Hirasawa 《Journal of nanoparticle research》2010,12(8):2747-2755
Gas suspended single-walled carbon nanotubes (SWCNTs) with single tube diameter smaller than 2 nm and length of longer than 500 nm were generated by simple and continuous system using laser ablation technique under atmospheric conditions. Graphite target containing 0.5 wt%-nickel and 0.5 wt%-cobalt was ablated by Nd:YAG laser in an electrical furnace under atmospheric pressure of nitrogen flow that allowed one step and continuous synthesis of the SWCNTs. Size distribution of the gas suspended SWCNTs aerosol was measured using size-classification by a differential mobility analyzer (DMA) coupled with a condensation particle counter (CPC) used as a detector. Characteristics of SWCNT aerosol generated under the different temperature were also investigated using scanning and transmission electron microscopes and Raman scattering. Mono-mobility SWCNT aerosol with mobility diameter of 100 and 200 nm was successfully prepared after the size separation using a DMA. 相似文献
92.
Formal [2+2+1] cycloaddition reaction involving acetylenes, aromatic imines, and CO was achieved by radical chain reaction, which gave five‐membered unsaturated lactams in modest to good yields. When we used 5‐chloropentyne, sequential carbonylation took place accompanied with double annulation events to give a cyclohexanone‐fused lactam in excellent stereoselectivity. 相似文献
93.
We investigate the Hubbard model on the anisotropic triangular lattice by means of the cellular dynamical mean-field theory. The phase diagram determined in the Hubbard interaction versus temperature plane shows novel reentrant behavior in the Mott transition due to the competition between Fermi-liquid formation and magnetic correlations under geometrical frustration. We demonstrate that the reentrant behavior is characteristic of the Mott transition with intermediate geometrical frustration and indeed consistent with recent experimental results of organic materials. 相似文献
94.
We developed a compact three-stage Ti:sapphire amplifier laser system that produced peak power in excess of 100 TW for a pulse duration of less than 19 fs and an average power of 19 W at a 10-Hz repetition rate. A final 40-mm-diameter Ti:sapphire amplifier is pumped by a Nd:YAG master-oscillator-power-amplifier system that produces ~7-J output of 532-nm radiation. The spatial beam quality is approximately 2 times diffraction limited for the full amplified compressed output pulse. With f/3 optics, this system should therefore be capable of producing a focused intensity of ~3x10(20) W/cm(2) . 相似文献
95.
96.
Takuma Tahara Dr. Shuichi Suzuki Prof. Dr. Masatoshi Kozaki Prof. Dr. Daisuke Shiomi Dr. Kenji Sugisaki Prof. Dr. Kazunobu Sato Prof. Dr. Takeji Takui Yota Miyake Prof. Dr. Yuko Hosokoshi Prof. Dr. Hiroyuki Nojiri Prof. Dr. Keiji Okada 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(29):7201-7209
The spin–spin and magnetic properties of two (nitronyl nitroxide)-(di-p-anisylamine-phenothiazine) diradical cation salts, ( DAA-PTZ ) + -NN⋅ MBr4− (M=Ga, Fe), have been investigated. These diradical-cation species were prepared by the cross-coupling of iodophenothiazine DAA-PTZ-I with NN-AuPPh3 followed by oxidation with the thianthrenium radical cation ( TA+⋅ MBr4−). These salts were found to be highly stable under aerobic conditions. For the GaBr4 salt, large ferromagnetic intramolecular and small antiferromagnetic intermolecular interactions (J1/kB=+320 K and J2/kB=−2 K, respectively) were observed. The magnetic property of the Fe3+ salt was analyzed by using a six-spin model assuming identical intramolecular exchange interaction (J3/kB=+320 K) and the other exchange interactions (J4/kB=−7 K and J5/kB=−4 K). A significant color change was observed in the UV/Vis/NIR absorption spectra upon electrochemical oxidation of the doublet DAA-PTZ-NN to the triplet ( DAA-PTZ ) + -NN . 相似文献
97.
98.
Takuma Morozumi Ryota Matsuoka Takashi Nakamura Tatsuya Nabeshima 《Chemical science》2021,12(22):7720
Tris–chelate metal complexes of unsymmetrical bidentate ligands can form two geometric stereoisomers, facial (fac) and meridional (mer) isomers. Due to the small difference in their properties, the highly-selective synthesis of one of the isomers is challenging. We now designed a series of tripodal ligands with a tris(3-(2-(methyleneoxy)ethoxy)phenyl)methane pivot. Surprisingly, the ratio of the fac/mer isomers of the triply helical FeII complexes significantly changed depending on the solvents. To the best of our knowledge, this is the first example of fac/mer isomerism of a labile tris(2,2′-bipyridine) FeII complex governed by the solvent. Furthermore, well-defined self-assemblies were quantitatively produced by imine bond formation with a suitable diamine. The supramolecular assemblies contained only the fac isomer even though a mixture of the two isomers existed in solution before the condensation reaction. Namely, the self-assembly formation effectively adjusted the geometries of the building unit that results in the suitable supramolecular structure.The novel tripodal complexes isomerize in response to environmental change, and well-defined self-assemblies were quantitatively produced by imine bond formation. 相似文献
99.
Meta and para derivatives of phenylene bis(succinic anhydride) and bis(glutaric anhydride) were obtained from 1,3- and 1,4-bis(β-cyano-β-carbethoxyvinyl)benzene with potassium cyanide or Meldrum acid followed by hydrolysis with concentrated hydrochloric acid and dehydration with acetic anhydride. Aliphatic polyimides were prepared from these anhydrides with six aromatic diamines through thermal ring closure of polyamic acids obtained by solution polymerization in dimethylacetamide, and thermal stability of these polyimides was examined by thermogravimetric analysis. 相似文献
100.
Keiji Yamamoto Takuma Nakao Etsuo Yonemochi Toshio Oguchi 《Journal of inclusion phenomena and macrocyclic chemistry》1996,25(1-3):121-124
The inclusion process of naphthalene into heptakis-(2,6-di-O-methyl)--cyclodextrin (DMCD) during the sealed heating was investigated by using solid state time,resolved fluorescent analysis. Fluorescence lifetimes of naphthalene in naphthalene crystals and in inclusion complex with DMCD prepared by coprecipitation were determined 59 ns and 88 ns, respectively. Fluorescence lifetime of naphthalene monomer becomes longer after inclusion complex formation. Fluorescence lifetimes of naphthalene monomer and excimer in the sealed heating complex were determined about 80 ns and 100 ns, respectively. By setting the observing wavelength of time resolved fluorescent analysis at 355 nm, the formation and the decay of the excimer state of naphthalene during the sealed heating process were successfully confirmed. 相似文献