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61.
A method for fabricating epoxy resin films dispersing the surface‐modified barium titanate (BT) particles (BT‐epoxy resin composite films) are proposed. BT particles with a size of 7.8 nm and a crystal size of 8.6 nm were synthesized with a complex alkoxide method. To introduce epoxy groups on the BT particle surface, the BT particles were surface‐modified with 2‐(3,4‐epoxycyclohexyl)‐ethyltrimethoxysilane. A precursor solution, which was prepared by prereacting 2,2‐bis(4‐glycidyloxyphenyl)propane (BGPP) and phthalic anhydride in 4‐butyrolactone and adding the surface‐modified BT particles to the prereacting solution, was spin‐coated on glass substrates to fabricate the composite films. An increase in BT volume fraction in film increased dielectric constant of the composite film while keeping dissipation factor below 0.03. The dielectric constant attained 10.8 at a BT volume fraction of 30% in film that was around twice higher than pure epoxy resin film. POLYM. COMPOS., 31:1179–1183, 2010. © 2009 Society of Plastics Engineers 相似文献
62.
N. Momono T. Kurosawa Y. Amakai Y. Sato T. Suzuki H. Takano S. Murayama A. Sakai M. Oda M. Ido 《Journal of Superconductivity and Novel Magnetism》2010,23(5):785-787
The Raman scattering experiments were carried out in Zn-doped and Zn-free Bi2Sr2CaCu2O8+y
with optimal hole concentration below and above T
c
. The energy of pair-breaking peak in the B
1g
Raman spectrum, corresponding to the magnitude of superconducting gap 2Δ
0, is suppressed by 1% Zn-doping. In the normal state, the B
1g
Raman spectrum for Zn-doped sample shows no pseudogap behaviour, suggesting that the pseudogap is strongly smeared by Zn-doping. 相似文献
63.
Katayama I Koga S Shudo K Takeda J Shimada T Kubo A Hishita S Fujita D Kitajima M 《Nano letters》2011,11(7):2648-2654
Ultrafast dynamics of surface-enhanced Raman scattering (SERS) was investigated at cleaved graphite surfaces bearing deposited gold (Au) nanostructures (~10 nm in diameter) by using sensitive pump-probe reflectivity spectroscopy with ultrashort (7.5 fs) laser pulses. We observed enhancement of phonon amplitudes (C═C stretching modes) in the femtosecond time domain, considered to be due to the enhanced electromagnetic (EM) field around the Au nanostructures. Finite-difference time-domain (FDTD) calculations confirmed the EM enhancement. The enhancement causes drastic increase of coherent D-mode (40 THz) phonon amplitude and nanostructure-dependent changes in the amplitude and dephasing time of coherent G-mode (47 THz) phonons. This methodology should be suitable to study the basic mechanism of SERS and may also find application in nanofabrication. 相似文献
64.
65.
Hitoshi Morioka Keisuke Saito Shintaro Yokoyama Takahiro Oikawa Toshiyuki Kurosawa Hiroshi Funakubo 《Journal of Materials Science》2009,44(19):5318-5324
Epitaxial Pb(Zr0.35Ti0.65)O3 (PZT) thin films with tetragonal symmetry and thicknesses ranging from 45 to 230 nm were grown at 540 °C on SrRuO3-coated (001)SrTiO3 substrates by pulse-injected metalorganic chemical vapor deposition. The effect of the film thickness on the ferroelectric
domain structure and the dielectric and ferroelectric properties were systematically investigated. Domain structure analysis
of epitaxial PZT films was accomplished with high-resolution X-ray diffraction reciprocal space mapping and high-resolution
transmission electron microscopy. Fully polar-axis (c-axis)-oriented epitaxial PZT thin films with high ferroelectric polarization values [e.g., remanent polarization (P
r) ~ 90 μC/cm2] were observed for film thicknesses below 70 nm. Films thicker than 70 nm had a c/a/c/a polydomain structure and the relative volume fraction of c-domains monotonously decreased to about 72% on increasing the film thickness up to 230 nm , and finally P
r diminished to about 64 μC/cm2 for the 230-nm-thick epitaxial film. These polarization values were in good agreement with the estimated values taking into
account the volume fraction of the c-axis-oriented domains while assuming a negligible contribution of 90° domain reorientation caused by an externally applied
electric field. 相似文献
66.
Bismuth nano-Hall probes with dimensions ~120 × 120 nm were fabricated by focused ion beam milling and used for the direct room temperature magnetic imaging of crystalline garnet thin films and strontium ferrite permanent magnets by scanning Hall probe microscopy. At driving currents of 40 μA, the Hall coefficient and magnetic field sensitivity of the Bi nano-Hall probes were 3.3 × 10-4 Ω/G and 7.2 G/√Hz, respectively 相似文献
67.
Ayaka Koma Shunichi Asai Chikashi Minemura Sachi Oshima Takashi Kinoshita Naoko Kikkawa Keiichi Koshizuka Shogo Moriya Atsushi Kasamatsu Toyoyuki Hanazawa Katsuhiro Uzawa Naohiko Seki 《International journal of molecular sciences》2021,22(18)
We newly generated an RNA-sequencing-based microRNA (miRNA) expression signature of head and neck squamous cell carcinoma (HNSCC). Analysis of the signature revealed that both strands of some miRNAs, including miR-139-5p (the guide strand) and miR-139-3p (the passenger strand) of miR-139, were downregulated in HNSCC tissues. Analysis of The Cancer Genome Atlas confirmed the low expression levels of miR-139 in HNSCC. Ectopic expression of these miRNAs attenuated the characteristics of cancer cell aggressiveness (e.g., cell proliferation, migration, and invasion). Our in silico analyses revealed a total of 28 putative targets regulated by pre-miR-139 (miR-139-5p and miR-139-3p) in HNSCC cells. Of these, the GNA12 (guanine nucleotide-binding protein subunit alpha-12) and OLR1 (oxidized low-density lipoprotein receptor 1) expression levels were identified as independent factors that predicted patient survival according to multivariate Cox regression analyses (p = 0.0018 and p = 0.0104, respectively). Direct regulation of GNA12 and OLR1 by miR-139-3p in HNSCC cells was confirmed through luciferase reporter assays. Moreover, overexpression of GNA12 and OLR1 was detected in clinical specimens of HNSCC through immunostaining. The involvement of miR-139-3p (the passenger strand) in the oncogenesis of HNSCC is a new concept in cancer biology. Our miRNA-based strategy will increase knowledge on the molecular pathogenesis of HNSCC. 相似文献
68.
Shunichi Manabe Chikao Nishino Kazuhiro Matsushita 《Journal of chemical ecology》1985,11(9):1275-1287
From the relationship between structures of the 2-substituents of verbanyl analogs and their sex pheromone activities to the American cockroach, electron density of the carbonyl oxygen atom in the substituent, as estimated by the [17O]NMR chemical shift, was estimated to be an important factor which influenced the activity, in addition to length of the substituent and the position of the carbonyl group. (+)-Verbanyl methylcarbonate (XX), possessing the highest electron density on the carbonyl oxygen atom, showed the strongest activity among the analogs.For Part X, see Manabe et al., 1983. J. Chem. Ecol. 9:533–549. 相似文献
69.
Prof. Minoru Yoshimoto Satoshi Kobirata Wataru Sakamoto Hidenobu Aizawa Shigeru Kurosawa 《仪器科学与技术》2013,41(5):495-505
Abstract The present work reports the new characteristics of the immersion‐angle dependence of the resonant‐frequency shift (ΔF) of the one‐face sealed quartz crystal microbalance (QCM) in three types of Newtonian liquids, i.e., sucrose, glucose, and glycerol solutions. Below some 1.80×10?2 g cm?2 · s?1/2, the ΔF values are dependent on the immersion angles in all solutions. However, we have found that the transition phenomenon of ΔF occurs between 1.78×10?2 and 4.80×10?2 g · cm?2 · s?1/2 in the sucrose solution, between 1.75×10?2 and 4.34×10?2 g · cm?2 · s?1/2 in the glucose solution and between 1.83×10?2 and 3.03×10?2 g · cm?2 · s?1/2 in the glycerol solution, respectively. Moreover, above the concentrations of the end points of the transition phenomenon, the ΔF values of the sucrose solution are equal to those of 90° at all immersion angles. On the other hand, those of the glucose and the glycerol solutions are the same as those of 30°. This difference may be caused by inherent characteristics of adsorption to the surface of the QCM electrode. 相似文献
70.
Shunichi Hasegawa Takahiro Nishiwaki Hitoe Habuchi Shoji Nitta Shuichi Nonomura 《Fullerenes, Nanotubes and Carbon Nanostructures》1995,3(3):313-325
The CPM spectra of fullerene films was measured to obtain the below gap absorption. The optical energy gap Eo was obtained by using the Tauc's plots. Eo did not change greatly with intercalated impurities. The absorption due to intercalated impurities was found below 1.6eV. 相似文献