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排序方式: 共有535条查询结果,搜索用时 46 毫秒
41.
Yuhiro Iwamoto Hiroshi Yamaguchi Xiao-Dong Niu 《Journal of magnetism and magnetic materials》2011,323(10):1378-1383
The magnetic body force in boiling two-phase temperature-sensitive magnetic fluid (TSMF) flow is known to effectively increase the driving force of magnetic fluid in a non-uniform magnetic field. Based on this mechanism, in the present study, a binary TSMF, which is a mixture of the TSMF and a low-boiling-saturation-temperature organic solution, is proposed to be used in a heat transport device to enhance its circulation. In order to see its performance in the heat transport device, the pressure difference at different heated temperatures, magnetic fields and inclination angles of the heating section are investigated experimentally and theoretically. Results showed that the driving force increases remarkably due to more gas phase appearing in the test fluid and the magnetization of it decreasing. At low magnetic field the driving force is enhanced greatly when the inclination angle is close to 60°, while at high magnetic field the driving force is remarkably enhanced due to the effect of the magnetic force in the inclination angle range from 0° to 30° and 60° to 90°. 相似文献
42.
Makoto Kudo Tomoyoshi Mishima Satoshi Iwamoto Toshihiro Nakaoka Yasuhiko Arakawa 《Physica E: Low-dimensional Systems and Nanostructures》2004,21(2-4):275
Self-assembled GaSb quantum dots (QDs) with a photoluminescence wavelength longer than 1.3 μm were successfully grown by suppressing the replacement of As and Sb on the surface of the GaSb QDs. This result means that GaSb can thus join InAs or GaInAs as a suitable material for QD lasers for optical communications. 相似文献
43.
The decaying process of a large surface potential of as-deposited Alq3 film was analyzed with consideration of electrostatic energies stored in the film. The analysis includes the cooperative molecular field effect and it shows that the derived equilibrium condition of dipolar films with electron traps supports the concept of the alignment of Fermi-level of metal and surface Fermi-level of dipolar films. The potential decay of Alq3 films on Al electrodes by photo-exposure is explained due to detrapping of trapped electrons that are immediately transported to the injected electrodes along with the disordering of polar structure of Alq3 films. 相似文献
44.
Akira Iwamoto 《Zeitschrift für Physik A Hadrons and Nuclei》1994,349(3-4):265-268
Semiclassical treatment of the tunneling through a multi-dimensional potential barrier is given. We discuss first about methods to calculate the minimum action trajectory. Next, we discuss the adiabatic approximation to the minimum action trajectory. We apply these two methods to the calculation of spontaneous fission. Finally we discuss some problems which should be solved to calculate more realistic penetration problems. 相似文献
45.
Y. Kobayashi M. Katada H. Sano T. Okada K. Asai M. Iwamoto F. Ambe 《Hyperfine Interactions》1990,54(1-4):585-589
99Ru,61Ni,57Fe and119Sn Mössbauer spectroscopic studies were made on ternary intermetallic compounds containing ruthenium, RuxY3?xZ (Y=Fe, Ni; Z=Si, Sn). In the system of RuxFe3?xSi, two different hyperfine magnetic fields were observed at the99Ru nuclei (H hf[Ru]) in the range ofx≤1.0 and the magnitude of eachH hf[Ru] was found to decrease with an increase in the ruthenium concentrationx. Both the99Ru and119Sn Mössbauer spectra of Ru2FeSn could be analyzed with two sets of magnetically split lines. The61Ni Mössbauer spectra of Ru2NiSn were obtained at 5 and 77 K. 相似文献
46.
Dr. Shintaro Ishida Dr. Takashi Abe Dr. Fumiya Hirakawa Tomoyuki Kosai Katsuhiro Sato Prof. Dr. Mitsuo Kira Prof. Dr. Takeaki Iwamoto 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(43):15100-15103
A persistent dialkylsilanone was synthesized by the dehydrobromination of a dialkylbromosilanol with tris(trimethylsilyl)silyl potassium in solution at ?80 °C: It was characterized by NMR and IR spectroscopy, and was tested in several reactions. In 29Si NMR spectrum in [D8]toluene, the signal due to the unsaturated silicon nuclei was observed at 128.7 ppm. Reactions of the dialkylsilanone with water and mesitonitrile oxide gave a silanediol and a [2+3] cycloadduct, respectively. The silanone remains intact in [D8]toluene below ?80 °C for at least two days, while it undergoes unprecedented isomerization to give a siloxysilene by means of 1,3‐silyl migration at higher temperatures. 相似文献
47.
Michiko Shimizu Tsuguyuki Saito Yoshiharu Nishiyama Shinichiro Iwamoto Hiroyuki Yano Akira Isogai Takashi Endo 《Macromolecular rapid communications》2016,37(19):1581-1586
The dimensions of nanocelluloses are important factors in controlling their material properties. The present study reports a fast and robust method for estimating the widths of individual nanocellulose particles based on the turbidities of their water dispersions. Seven types of nanocellulose, including short and rigid cellulose nanocrystals and long and flexible cellulose nanofibers, are prepared via different processes. Their widths are calculated from the respective turbidity plots of their water dispersions, based on the theory of light scattering by thin and long particles. The turbidity‐derived widths of the seven nanocelluloses range from 2 to 10 nm, and show good correlations with the thicknesses of nanocellulose particles spread on flat mica surfaces determined using atomic force microscopy.
48.
Momiyama N Konno T Furiya Y Iwamoto T Terada M 《Journal of the American Chemical Society》2011,133(48):19294-19297
Chiral bis-phosphoric acid 1 was designed to identify a new class of structural features in chiral Br?nsted acid catalysts. X-ray diffraction analysis revealed the single atropisomer 1, bearing S axial chirality at 3,3'-biaryl substituents on (R)-binaphthyl and intramolecular hydrogen bonding between the two phosphoric acid moieties. The newly designed bis-phosphoric acid 1 was evaluated in the Diels-Alder reaction of α,β-unsaturated aldehydes 4 with 1-N-acylamino-1,3-butadienes 3. After systematic variation of the catalyst substituents, as well as the N-acyl substituents of 1,3-butadiene, the use of an N-Cbz amidodiene 3a in the presence of bis-phosphoric acid 1e with a 2,4,6-tri-isopropylphenyl group was found to be optimal to yield the 1S,6R enantiomeric product 5aa in a Diels-Alder reaction of acrolein (4a). Application of this method to substituted substrates was found to be an efficient approach to the enantioselective synthesis of 3- and 3,6-substituted cyclic formylcarbamates 5. The specific character as well as the utility of 1e was further established by comparing its enantioselectivity, absolute stereochemistry, and catalytic efficiency with those of mono-phosphoric acid 2. 相似文献
49.
Yanagisawa M Iwamoto M Kato A Yoshikawa K Oiki S 《Journal of the American Chemical Society》2011,133(30):11774-11779
We report a method for the successful reconstitution of the KcsA potassium channel with either an outside-out or inside-out orientation in giant unilamellar vesicles, using the droplet-transfer technique. The procedure is rather simple. First, we prepared water-in-oil droplets lined with a lipid monolayer. When solubilized KcsA was encapsulated in the droplet, it accumulated at monolayers of phosphatidylglycerol (PG) and phosphoethanolamine (PE) but not at a monolayer of phosphatidylcholine (PC). The droplet was then transferred through an oil/water interface having a preformed monolayer. The interface monolayer covered the droplet so as to generate a bilayer vesicle. By creating chemically different lipid monolayers at the droplet and oil/water interface, we obtained vesicles with asymmetric lipid compositions in the outer and inner leaflets. KcsA was spontaneously inserted into vesicles from the inside or outside, and this was accelerated in vesicles that contained PE or PG. Integrated insertion into the vesicle membrane and the KcsA orientation were examined by functional assay, exploiting the pH sensitivity of the opening of the KcsA when the pH-sensitive cytoplasmic domain (CPD) faces toward acidic media. KcsA loaded from the inside of the PG-containing vesicles becomes permeable only when the intravesicular pH is acidic, and the KcsA loaded from the outside becomes permeable when the extravesicular pH is acidic. Therefore, the internal or external insertion of KcsA leads to an outside-out or inside-out configuration so as to retain its hydrophilic CPD in the added aqueous side. The CPD-truncated KcsA exhibited a random orientation, supporting the idea that the CPD determines the orientation. Further application of the droplet-transfer method is promising for the reconstitution of other types of membrane proteins with a desired orientation into cell-sized vesicles with a targeted lipid composition of the outer and inner leaflets. 相似文献
50.
Chang JC Tomlinson ID Warnement MR Iwamoto H DeFelice LJ Blakely RD Rosenthal SJ 《Journal of the American Chemical Society》2011,133(44):17528-17531
The serotonin (5-hydroxytryptamine, 5-HT) transporter (SERT) protein plays a central role in terminating 5-HT neurotransmission and is the most important therapeutic target for the treatment of major depression and anxiety disorders. We report an innovative, versatile, and target-selective quantum dot (QD) labeling approach for SERT in single Xenopus oocytes that can be adopted as a drug-screening platform. Our labeling approach employs a custom-made, QD-tagged indoleamine derivative ligand, IDT318, that is structurally similar to 5-HT and accesses the primary binding site with enhanced human SERT selectivity. Incubating QD-labeled oocytes with paroxetine (Paxil), a high-affinity SERT-specific inhibitor, showed a concentration- and time-dependent decrease in QD fluorescence, demonstrating the utility of our approach for the identification of SERT modulators. Furthermore, with the development of ligands aimed at other pharmacologically relevant targets, our approach may potentially form the basis for a multitarget drug discovery platform. 相似文献