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排序方式: 共有520条查询结果,搜索用时 15 毫秒
91.
We investigated the surface potential built across the electrode/fullerene (C60) or copper phthalocyanine (CuPc) interface and C60/CuPc interface as a function of the thickness of the semiconductor film in the dark condition and under illumination. The surface potential of C60 on Au, Al and Mg changes negatively with the increment of film thickness and it saturates at − 0.25, − 1.0 and − 1.5 V within 20 nm. The Fermi level alignment at C60/electrode interface is established within ∼ 20 nm from electrode, and very high electric field exists due to the displacement of negative electronic charges from electrode into C60. On the other hand, the surface potential of CuPc on ITO changes to + 0.1 V, and the work functions of C60 and CuPc were estimated as 5.0 eV and 4.7 eV. C60 film also accepts electrons from CuPc at hetero-junction interface, and the Fermi-level alignment was again obtained at C60/CuPc interface under illumination. The built-in potential of ca. 0.3 V formed at C60/CuPc interface was considered as the origin of the reduction of open-circuit voltage in ITO/CuPc/C60/Au device compared with the optimum value of 0.6 V. On the other hand, the very high electric field formed at C60/Mg contact improved the photovoltaic properties. 相似文献
92.
Obayashi H Kawabe Y Makitsubo H Watanabe R Kameyama Y Huang S Takenouchi Y Ito A Kamihira M 《Journal of Bioscience and Bioengineering》2012,113(3):381-388
Site-specific gene recombination systems, such as Cre/loxP, have been used for genetic modification of cells and organisms in both basic and applied research. We previously developed an accumulative gene integration system (AGIS), in which target gene cassettes could be repeatedly integrated into a pre-determined site on a plasmid or cellular genome by recombinase-mediated cassette exchange (RMCE), using Cre and mutated loxPs. In the present study, we designed a simplified AGIS. For gene integration into a target site, the previous system used two loxP sites in the acceptor DNA, whereas the new system uses a single loxP site. The gene integration reactions were repeated four times in vitro using Cre protein and specific plasmids. The expected integration reactions mediated by Cre occurred at the loxP sites, resulting in integration of four target genes. The system was also used for genomic integration of reporter genes using Chinese hamster ovary (CHO) cells. The reporter genes were efficiently introduced into the CHO genome in a Cre-dependent manner, and transgene expression was detected after the integration reaction. The expression levels of the reporter genes were enhanced, corresponding to the increase of transgene copy number. Recombinase-mediated AGIS provides a useful tool for the modification of cellular genomes. 相似文献
93.
Dioscin Derived from Solanum melongena L. “Usukawamarunasu” Attenuates α‐MSH–Induced Melanogenesis in B16 Murine Melanoma Cells via Downregulation of Phospho‐CREB and MITF 下载免费PDF全文
94.
95.
Wang C Lee DH Hexemer A Kim MI Zhao W Hasegawa H Ade H Russell TP 《Nano letters》2011,11(9):3906-3911
The morphologies of a poly(1,4-isoprene)-block-polystyrene-block-poly(2-vinyl pyridine) (IS2VP) copolymer were investigated using resonant soft X-ray scattering (RSoXS) together with scanning force microscopy, small-angle X-ray scattering, and electron microscopy. Differences in the nanoscopic morphologies in the bulk and thin film samples were observed arising from the competition between segmental interactions between the blocks and the substrate and the surface energies of each block. Using soft X-rays at selected photon energies to isolate the scattering contribution from different polymer blocks, RSoXS unambiguously defined the complex morphology of the triblock copolymer. In the bulk sample, two nested, hexagonal arrays of P2VP and PI cylindrical microdomains residing in the PS matrix were observed. The cylindrical microdomains of one component were found to be located at the interstitial sites of the hexagonal array of the other component that has the larger d spacing. In solvent-annealed thin films with 40 nm in thickness, a hexagonal array of core-shell microdomains of P2VP cores with PS shells that reside in a PI matrix were observed. 相似文献
96.
97.
Nan Xia Yongliang Wang Ping Zheng Go Sakaguchi Kenji Saijo Hirokazu Hasegawa 《Polymer》2011,52(8):1772-1780
In the present work, we report our work concerning the synthesis of heteropolymers of poly(?-caprolactone)-polyoxomolybdate-poly(?-caprolactone) using ring-opening polymerization (ROP) of ?-caprolactone monomer initiated by two hydroxyl groups attached on the two sides of a polyoxomolybdate cluster which was organically modified using pentaerythritols. Since the hydroxyl groups on polyoxomolybdate macroinitiator are less reactive, ring-opening polymerization were finally carried out by using 4,4′-(dimethylamino) pyridine to activate ?-caprolactone monomer. The polyoxomolybdate-containing heteropolymers were confirmed in detail by 1H NMR, FT-IR, GPC, TGA and XPS methods. Although the size of polyoxomolybdate cluster is extremely small compared to PCL chains, it was also found that POM played an important role in crystallization process. Self-assembly of such heteropolymers in mixed solvents were investigated and the analysis of formed spherical aggregates with multiple concaves on the surface was supported by TEM results and 3D electron tomography. 相似文献
98.
99.
100.
Suning Luo Koichi Okada Shigemi Kohiki Fuki Tsutsui Hirokazu Shimooka Fumiya Shoji 《Materials Letters》2009,63(6-7):641-643
Polycrystalline thin films of indium tin oxide sputter-deposited in the working gas containing hydrogen of 0.3–1.5% exhibited transmittance of ≥ 80% for visible lights and blue-shift of ≥ 0.1 eV in the optical absorption energy. The film deposited in the gas containing hydrogen of 1% demonstrated almost flat temperature-dependent resistivity and the lowest resistivity of ≈ 1.5 × 10? 4 Ω cm at room temperature. The carrier density showed an inverse V-shaped behavior with the maximum at the hydrogen concentration of 1%. The mobility stayed at almost constant below the hydrogen concentration of 1% and dropped rather rapidly above 1%. 相似文献