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排序方式: 共有229条查询结果,搜索用时 15 毫秒
141.
142.
Hideaki Ishida Makoto Handa Takahisa Ikeue Jun Taguchi Masahiro Mikuriya 《Chemical Papers》2010,64(6):767-775
Deuterated dinuclear ruthenium(II,III) 3,4,5-tri(ethoxy-d
5)benzoate, [Ru2{3,4,5-(C2D5O)3C6H2-COO}4Cl]
n
, was synthesized by a reaction of [Ru2(C2H5COO)4Cl]
n
and 3,4,5-tri(ethoxy-d
5)benzoic acid and characterized by single-crystal X-ray analysis as well as IR, UV-VIS, and 1H NMR spectra, and compared with those of the undeuterated complex [Ru2{3,4,5-(C2H5O)3C6H2COO}4Cl]
n
. Single-crystal X-ray analysis showed that chloride ligands bridge the dinuclear ruthenium(II,III) units at the axial positions
to form a zigzag chain molecule with the Ru1-Cl-Ru2 angle of 123.82(4)°. 1H NMR spectra in CD2Cl2 displayed a broad signal attributable to o-H atoms on the phenyl rings of the benzoate ligands from approximately δ = 23 to δ = 32 at 25°C and several signals from approximately δ = −50 to δ = 50 at −80°C. These spectra show the preservation of the polymeric or oligomeric chain structure in dichloromethane, which
is supported by the solution behavior confirmed by the UV-VIS spectra and electronic conductance. 相似文献
143.
Shiina I Hashizume M Yamai YS Oshiumi H Shimazaki T Takasuna YJ Ibuka R 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(22):6601-6608
Octalactin A, an antitumor agent containing an eight-membered lactone moiety, has been stereoselectively prepared by means of enantioselective aldol reactions of selected silyl enolates with achiral aldehydes, promoted by a chiral Sn(II) complex. The medium-sized lactone part was effectively constructed by way of a new and rapid mixed-anhydride lactonization using 2-methyl-6-nitrobenzoic anhydride (MNBA) with a catalytic amount of 4-(dimethylamino)pyridine (DMAP) or 4-(dimethylamino)pyridine 1-oxide (DMAPO). The use of only 5 mol % of DMAP or 2 mol % of DMAPO rapidly promoted formation of the medium-sized ring of the octalactin, demonstrating the remarkable efficiency of the new lactonization protocol. 相似文献
144.
Laser action on a single spatially chaotic wave function is obtained as a final stable state in a nonlinear dynamical model of a stadium shaped resonant cavity with an active medium. The stable single-mode lasing state corresponds to a particular metastable resonance of the cavity which wins a competition among multiple modes with positive net linear gain and has a distinct lasing threshold. 相似文献
145.
Noriaki Nishi Takahisa Jitsuno Koji Tsubakimoto Shinichi Matsuoka Noriaki Miyanaga Masahiro Nakatsuka 《Optical Review》2000,7(3):216-220
A two-dimensional multi-lens array 350 mm in diameter with spherical element lenses has been tested to improve the irradiation uniformity of a high power glass laser for inertial confinement fusion (ICF). A circular shape for the element lens aperture is chosen to eliminate azimuthally asymmetric intensity distribution. An approximate flat-top intensity distribution is obtained with a lens array of 37 lenses. Beam patterns of a coherent laser and partially coherent light (PCL) with the random phase plate (RPP) and the multi-lens array (MLA) are measured in a GEKKO XII glass laser system. Spherical mode structure of the irradiation nonuniformity of 5.6% with MLA is estimated with cos3 θ distribution of absorption coefficient in the target plasma. 相似文献
146.
Susumu Shinohara Takehiro Fukushima Satoshi Sunada Takahisa Harayama Kenichi Arai Kazuyuki Yoshimura 《Optical Review》2014,21(2):113-116
Time-domain properties of the output from quasistadium-shaped microcavity semiconductor lasers are studied. Ring modes generating a bidirectional output are selectively excited by partial pumping. We observe a high anticorrelation between the two beams output from the ring modes. This can be considered as the generalization of alternate oscillations reported previously. We find that the outputs exhibit a robust slow modulation of 4–10 MHz, and explain it by the quasi-degeneracy of the resonator modes. 相似文献
147.
Mengyu You Daisuke Sakakibara Kota Makino Yonosuke Morishita Kazutoshi Matsumura Yuta Kawashima Manao Yoshikawa Mahiro Tonosaki Kazutaka Kanno Atsushi Uchida Satoshi Sunada Susumu Shinohara Takahisa Harayama 《Entropy (Basel, Switzerland)》2022,24(11)
By numerical simulations and experiments of fully chaotic billiard lasers, we show that single-mode lasing states are stable, whereas multi-mode lasing states are unstable when the size of the billiard is much larger than the wavelength and the external pumping power is sufficiently large. On the other hand, for integrable billiard lasers, it is shown that multi-mode lasing states are stable, whereas single-mode lasing states are unstable. These phenomena arise from the combination of two different nonlinear effects of mode-interaction due to the active lasing medium and deformation of the billiard shape. Investigations of billiard lasers with various shapes revealed that single-mode lasing is a universal phenomenon for fully chaotic billiard lasers. 相似文献
148.
Dr. Akihito Konishi Yohei Minami Takahisa Hosoi Kouji Chiba Prof. Dr. Makoto Yasuda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(36):12688-12691
The Group 14 enolates play an important part in many organic reactions. Herein, the reduction of an α‐bromo ketone with germanium(II) salts cleanly afforded the corresponding germyl enolate as an isolatable species. This experimental reductive generation of a germyl enolate enabled us to characterize both C‐ and O‐bound tautomers derived from an identical precursor and to unveil the tautomeric mechanisms, including the kinetic parameters and the relative stability of these tautomers, along with confirmation from DFT calculations. Moreover, the highly coordinated germyl enolates were isolated by a stabilization process induced by adding ligands. All products were characterized by NMR spectroscopy and X‐ray crystallography. 相似文献
149.
Makoto Handa Hideaki Ishida Kayoko Ito Toshihiro Adachi Takahisa Ikeue Ichiro Hiromitsu Masahiro Mikuriya Kuninobu Kasuga 《Chemical Papers》2008,62(4):410-416
Polymeric complexes of ruthenium(II)-ruthenium(III) tetracarboxylato units linked by cyanato, thiocyanato, and selenocyanato
ligands [Ru2{O2C(CH2)mCH3}4(L)]
n
(m = 0, 4–7; L = OCN−, SCN−, and SeCN−) were prepared and characterized based on the elemental analyses, IR, and diffuse reflectance spectra. Magnetic susceptibilities
were measured at the temperature range of 4.5 K to 300 K, where the interdimer antiferromagnetic interactions were revealed.
The strongest interaction was exhibited in case of m = 7 and L = OCN−. 1H-NMR spectra of [Ru{O2C(CH2)7CH3}4(SCN)]
n
in CD2Cl2 showed broad signals which can be ascribed to polymeric species, as the addition of tetrabutylammonium thiocyanate caused
sharper signals due to the formation of [Ru2{O2C(CH2)7CH3}4(SCN)2]− adduct as the main species in the solution.
Dedicated to Professor Milan Melník on the occasion of his 70th birthday 相似文献
150.
Nara J Kajiyama H Hashizume T Suwa Y Heike S Matsuura S Hitosugi T Ohno T 《Physical review letters》2008,100(2):026102
The formation mechanism of one-dimensional Si islands on a H/Si(001)-(2x1) surface is studied using scanning tunneling microscopy/spectroscopy and first-principles calculations. We observed that one-dimensional islands that are made from dimer chains are formed at the initial growth stages similar to the bare Si(001) surface. It is found that the number of odd-numbered dimer chains is larger than that of even-numbered dimer chains. We propose the growth processes of the two types of growth edges to explain the observation. 相似文献