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941.
Takahide Y Konoike T Enomoto K Nishimura M Terashima T Uji S Yamamoto HM 《Physical review letters》2006,96(13):136602
The current-voltage characteristics of layered organic crystals theta-(BEDT-TTF)2MZn(SCN)4 (M = Cs, Rb) follow the power law with a large exponent (e.g., 8.4 at 0.29 K for M = Cs) over a wide range of currents in the low-temperature insulating state. The power-law characteristics are attributed to electric field-induced unbinding of electron-hole pairs that are thermally excited in the background of the two-dimensional charge order. The magnitude of crossover electric fields from Ohmic to the power-law characteristics indicates that the electron-electron Coulomb interaction is significantly long-ranged: The screening length is greater than 10 molecule sites. 相似文献
942.
Nakamichi S Kawaguchi Y Fukuda H Enami S Hashimoto S Kawasaki M Umekawa T Morino I Suto H Inoue G 《Physical chemistry chemical physics : PCCP》2006,8(3):364-368
Buffer-gas pressure broadening for the (3 0(0) 1)(III)<--(0 0 0) band of CO(2) in the 1600 nm region was investigated with continuous wave cavity ring-down spectroscopy within the temperature range 263-326 K. The measured absorption profiles were analyzed with Voigt functions. Pressure broadening coefficient, gamma(gas), and the temperature dependent parameter (broadening exponent), n, were determined for a variety of buffer gases: N(2), O(2), He, Ne, Ar, Kr and Xe. gamma(air) values estimated subsequently are 0.096(2) for R(0), 0.085(5) for P(8), 0.075(2) for P(16), 0.070(4) for P(26), and 0.069(2) for P(38) in units of cm(-1) atm(-1), where numbers in parentheses are one standard deviation in units of the last digits quoted. n(air) values are 0.77(4) for R(0), and 0.73(11) for P(8). 相似文献
943.
944.
945.
Ab initio calculations using 6-311G**, cc-pVDZ, and aug-cc-pVDZ, with (MP2, QCISD, CCSD(T)) and without (UHF) electron correlation, and density functional methods (BHandHLYP and B3LYP) predict that cyclization of the 5-aza-5-hexenoyl and (E)-6-aza-5-hexenoyl radicals proceed to afford the 5-exo products. At the CCSD(T)/cc-pVDZ//BHandHLYP/cc-pVDZ level of theory, energy barriers (deltaE(double dagger)) of 36.1 and 47.0 kJ mol(-1) were calculated for the 5-exo and 6-endo pathways for the cyclization of the 5-aza-5-hexenoyl radical. On the other hand, at the same level of theory, deltaE(double dagger) of 38.9 and 45.4 kJ mol(-1) were obtained for the 5-exo and 6-endo cyclization modes of (E)-6-aza-5-hexenoyl radical, with exothermicities of about 27 and 110 kJ mol(-1) calculated for the exo and endo modes, respectively. Under suitable experimental conditions, the 6-endo cyclization product is likely to dominate. Analysis of the molecular orbitals involved in these ring-closure reactions indicate that both reactions at nitrogen are assisted by dual orbital interactions involving simultaneous SOMO-pi* and LP-pi* overlap in the transitions states. Interestingly, the (Z)-6-aza-5-hexenoyl radical, that cannot benefit from these dual orbital effects is predicted to ring-close exclusively in the 5-exo fashion. 相似文献
946.
Fine metal particles (nanoparticles) stabilized on porous (polymeric) substrates can be considered as a model system of a high-performance catalyst. In the present study, the substrate was made using the periodic microphase-separated structure of a block copolymer as the template, and the Pd nanoparticles were formed inside the porous material by reduction of the Pd2+ ions with 1-propanol as the reductant. The three-dimensional morphology of such a polymer-Pd hybrid material was studied by transmission electron microtomography. The characteristic structural parameters of the hybrid, e.g., the penetration of the Pd nanoparticles into the polymer substrate, number density of the Pd nanoparticles, and size distribution of the Pd nanoparticles, were measured for the first time. 相似文献
947.
A phosphorus-containing hybrid porphyrin was successfully prepared via the BF3-promoted dehydrative condensation between sigma4-phosphatripyrrane and 2,5-bis[hydroxy(phenyl)methyl]thiophene. The NMR and UV-vis absorption spectra, electrochemical measurements, and DFT calculations revealed that the sigma3-P,N2,S-hybrid porphyrin exhibits high aromaticity as an 18pi-electron system in terms of both geometric and magnetic criteria. [structure: see text] 相似文献
948.
Iba S Kato Y Sekitani T Kawaguchi H Sakurai T Someya T 《Analytical and bioanalytical chemistry》2006,384(2):374-377
Inverter circuits have been made by connecting two high-quality pentacene field-effect transistors. A uniform and pinhole-free
900 nm thick polyimide gate-insulating layer was formed on a flexible polyimide film with gold gate electrodes and partially
removed by using a CO2 laser drilling machine to make via holes and contact holes. Subsequent evaporation of the gold layer results in good electrical
connection with a gold gate layer underneath the gate-insulating layer. By optimization of the settings of the CO2 laser drilling machine, contact resistance can be reduced to as low as 3 Ω for 180 μm square electrodes. No degradation of
the transport properties of the organic transistors was observed after the laser-drilling process. This study demonstrates
the feasibility of using the laser drilling process for implementation of organic transistors in integrated circuits on flexible
polymer films. 相似文献
949.
The synthesis and characterization of N,N'-p-xylylene-linked oligo-Janus [2]rotaxanes based on a permethylated alpha-cyclodextrin and their contractible and extendable nature coupled with photochromism are described. 相似文献
950.
Hong R Fernández JM Nakade H Arvizo R Emrick T Rotello VM 《Chemical communications (Cambridge, England)》2006,(22):2347-2349
Place exchange reactions were studied using dye displacement: subtle changes in ligand structure greatly affected both the rate of displacement and the stability of the monolayer. 相似文献