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排序方式: 共有773条查询结果,搜索用时 24 毫秒
1.
Dr. Yogesh Kumar Maurya Dr. Pingchun Wei Takahide Shimada Dr. Kazuhisa Yamasumi Dr. Shigeki Mori Prof. Dr. Ko Furukawa Dr. Hajime Kusaba Prof. Dr. Tatsumi Ishihara Prof. Dr. Yongshu Xie Dr. Masatoshi Ishida Prof. Dr. Hiroyuki Furuta 《化学:亚洲杂志》2021,16(7):743-747
A facile synthetic strategy towards conformationally stable chiral chromophores based on dimeric porphyrinoids has been established. A peculiar class of face-to-face intramolecularly interlocked corrole dimers were formed by the oxidative C−C coupling linked at the inner carbon sites upon simple treatment of copper(II) ions. Their intrinsic electronic structures were modulated by the peripheral corrole ring annulations, which lead to distinct optical properties and redox profiles. The stereogenic carbon centers implemented in the confused corrole skeleton provided a rationale for designing novel chiral materials. 相似文献
2.
Oleate-stabilized silver colloids of 5-nm-diameter were adsorbed to a toluene/water interface, and surface enhanced Raman scattering (SERS) spectra from these colloids were measured under the total internal reflection (TIR) condition. From the observed spectra, we examined the states of oleate ions and toluene molecules on silver colloids at the liquid/liquid interfacial region. The TIR-SERS spectra of oleate ions showed stronger peaks of the carboxylate group and the ethylene group than those of alkyl chains. From these results, it was found that the oleate ions were adsorbed on the silver surface in two different ways at the liquid/liquid interface; the carboxylate group adsorbed in the organic phase side, while the ethylene group adsorbed in the aqueous phase side. The shifts of the toluene in the interfacial SERS spectra were identical to those of bulk toluene, though the relative intensities among the peaks were not same. This result suggested that the toluene was adsorbed with a weak interaction, but was significantly enhanced by the local electromagnetic field at the colloid surface. 相似文献
3.
4.
Takanari Yasui Takeshi Ohtsuka Tetsu Suzuki Shigeki Okajima Kazuya Nakayama Mitsuru Tomioka Katsuhiro Kamimura Takeo Namekata Hiroaki Minamide Hiromasa Ito 《International Journal of Infrared and Millimeter Waves》2006,27(2):199-210
A new, wide-band, high-speed and high-sensitivity THz detector has been developed. The prototype detector consists of a parabolic
cylindrical mirror, a long wire antenna and a Schottky barrier diode. Direct detection measurements have shown a stable sensitivity
of 150 ± 50 V/W for 1–2 THz without any adjustments. The long wire antenna was fixed at the focus of parabolic cylindrical
mirror then it has been realized less operation steps, easy coupling to the external THz signals and a dramatic enhancement
in the practicality of this system. The optically polished mirror and frosted surface one showed comparable sensitivities,
thus easy polishing and less cost mirror fabrication can be applied for this system. The radiation pattern showed a maximum
radiation angle of approximately 23° with its dominant main lobe, which was attributed to the wire antenna character and confirmed
good agreements with classical antenna theory. 相似文献
5.
Shigeki Aida 《Journal of Functional Analysis》2007,251(1):59-121
We determine the limit of the bottom of spectrum of Schrödinger operators with variable coefficients on Wiener spaces and path spaces over finite-dimensional compact Riemannian manifolds in the semi-classical limit. These are extensions of the results in [S. Aida, Semiclassical limit of the lowest eigenvalue of a Schrödinger operator on a Wiener space, J. Funct. Anal. 203 (2) (2003) 401-424]. The problem on path spaces over Riemannian manifolds is considered as a problem on Wiener spaces by using Ito's map. However the coefficient operator is not a bounded linear operator and the dependence on the path is not continuous in the uniform convergence topology if the Riemannian curvature tensor on the underling manifold is not equal to 0. The difficulties are solved by using unitary transformations of the Schrödinger operators by approximate ground state functions and estimates in the rough path analysis. 相似文献
6.
Tetsuro Shimo Shigeki Matsuzaki Kenichi Somekawa 《Journal of heterocyclic chemistry》1994,31(2):387-390
6-(ω-Alkenyl)-2-pyrones 3a-c and 8a, b were prepared and the photochemical reactions were investigated. Photosensitized reactions of 3b, c gave intramolecular [2+2]-cycloadducts 11b, c as tricyclic lactones, site-and regio-specifically. They are not frontier-orbital-controlled adducts. On the other hand, 3a, 8a, b afforded cyclobutenecarboxylic acids, 10a, 14a, b , respectively. The end-ester group at the side-chain is thought not to be effective for the intramolecular phptoaddition. 相似文献
7.
Kiyonaka S Sugiyasu K Shinkai S Hamachi I 《Journal of the American Chemical Society》2002,124(37):10954-10955
In materials science, a dynamic property sensitive to an environmental change (heat, light, electric current, pH, and other chemical or physical changes) is indispensable for intelligent materials. Such organic materials, however, are very limited even in conventional polymers. This paper clearly demonstrates that, regardless of the low molecular weight, a glycosylated amino acid derivative newly screened by a combinatorial method forms a macroscopic supramolecular hydrogel that reversibly swells or shrinks in response to the external temperature. Using the unique thermal response of the present hydrogel, we carried out the controlled release of DNA and the perfect removal of bisphenol A from the polluted water. Recently, advanced supramolecular polymers, in which monomers are noncovalently connected, are expected to be highly advantageous over traditional polymers because of their tunable and recyclable characteristics. The present result newly confers a dynamic feature on the supramolecular polymers, which is desirable for the sophisticated application in many fields. 相似文献
8.
Toshio Masuoka H. Yasuda 《Journal of polymer science. Part A, Polymer chemistry》1981,19(11):2937-2946
Plasma polylmerization occurs in plasmas surrounded by surfaces and polymer formation is one of the complicated interactions that take place between active species and molecules which constitute surfaces and gas phases. Effects of reactor wall, substrate materials, flow rate, and discharge power on polymer formation, and properties of polymer deposits were investigated by ESCA, IR (infrared) spectroscopy, and the measurement of system pressure. The effect of surface is important at the initial stage of plasma polymerization which can be easily detected by the system pressure change; however, integrated properties such as IR spectroscopy and the deposition rate show the effect in a less pronounced manner. ESCA, which reflects the properties of surface (approximately 20 A? in depth), showed the effect of surface in an even less sensitive manner. The amount and properties (including the effects of surfaces) are dependent on plasma polymerization parameter W/FM(W, wattage; F, volume flow rate; and M, molecualar weight of monomer) and the location of deposition within a reactor. IR and ESCA data clearly showed the dependence of polymer properties on W/FM; i.e., increase of W and decrease of M to be equivalent. When all these factors were kept under control, the reproducibility of plasma polymerization was found to be excellent. 相似文献
9.
This work reports the principle, advantage, and limitations of analytical photoion spectroscopy which has been applied to dissociative photoionization processes for diatomic molecules such as H2, N2, CO, and NO. Characteristic features observed in the differential photoion spectra are summarized with a focus on (pre)dissociation of(i) multielectron excitation states commonly observed in the inner valence regions,(ii) shape resonances, and(iii) doubly charged parent ions. Possible origins for negative peaks in the differential spectra are discussed. This spectroscopy is applied to the reported photoion branching ratios for D2 (and H2 at high energies). The main findings are as follows: (1) The direct dissociation of theX 2Σ g + (1sσ g ) state of D 2 + , the two-electron excited state1Σ u + (2pσ u 2sσ g ) of D2, and the2Σ u + (2pσ u ) state of D 2 + appear clearly in the differential spectrum, as previously observed for H2. (2) Decay of H 2 + (D 2 + ) to H+ (D+) above 38 eV is due to the direct dissociation of highly excited states of H 2 + (D 2 + ) such as the2Σ g + (2sσ g ) and high-lying Rydberg states converging on H 2 2+ (D 2 2+ ). (3) In the ionization continuum of H 2 2+ (D 2 2+ ) peculiar dissociation pathways are observed. The differential photoion spectra for O2 derived from the reported photoion branching ratios are also presented. The (pre)dissociation of theb 4Σ g ? ,B 2Σ g ? , III2Π u ,2Σ u ? , and2,4Σ g ? states of O 2 + appears as the corresponding positive values in the spectra in accord with previous observations. Some other dissociation pathways possibly contributing to the spectra are discussed including dissociative double ionization. 相似文献
10.
Sano S Takehisa T Ogawa S Yokoyama K Nagao Y 《Chemical & pharmaceutical bulletin》2002,50(9):1300-1302
Tetrasubstituted (Z)-alkenes were readily prepared through the Horner-Wadsworth-Emmons reactions of methyl 2-[bis(2,2,2-trifluoroethyl)phosphono]propionate with aryl alkyl ketones by employing Sn(OSO(2)CF(3))(2) and N-ethylpiperidine. 相似文献