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981.
High-isolation polarization-independent optical circulator 总被引:2,自引:0,他引:2
A high-isolation polarization-independent optical circulator is reported. The circulator structure can sharply reduce isolation dependency on both the rotation error of a rotator and on extinction ratio of a polarizing beam splitter. As a result, the circulator has high isolation over a wide wavelength and temperature range. A 4-port circulator coupled with single-mode fibers was fabricated. Its measured insertion loss and isolation were <1.8 and >31.5 dB, respectively. Consequently, a loss ratio of over 29.7 dB has been realized. The isolation (which is free from reflections) was measured to be >45.1 dB. It is confirmed that the wavelength range for this kind of isolation over 40-dB is very wide. The measured range was wider than the measurement system limit of 90 nm 相似文献
982.
983.
Water hammer phenomena caused by a rapid valve closure in a one-component two-phase bubbly flow were investigated experimentally. The experiments were conducted in a horizontal tube of 21.4 mm in inner diameter and 16.17 m long in ranges of superficial liquid velocity jl from 0.5 to 1.5 m/s and of pressure from 0.25 to 1.5 MPa, using a refrigerant (R113), ethanol and water as the working fluid. The profiles of transient pressure, value of potential surge, and propagation velocity of the compression waves were obtained and discussed, comparing them with those in an air-water two-component two-phase flow. In particular, the pressure transient in a one-component two-phase flow is characterized by the existence of an exponential pressure decay just after the initial pressure rise. This phenomenon is closely related to the interface mass transfer. 相似文献
984.
Transfection of nearly senesced human fibroblasts with plasmids encoding HPV16 E6 protein or dominant-negative p53 mutants greatly increased their colony-forming ability. Isolated colonies with these plasmids showed extension of lifespan compared to those with a control plasmid. These data demonstrate that p53 plays a major role in senescence in normal human fibroblasts. 相似文献
985.
H Konishi T Takahashi K Kozaki Y Yatabe T Mitsudomi Y Fujii T Sugiura H Matsuda T Takahashi T Takahashi 《Canadian Metallurgical Quarterly》1998,17(16):2095-2100
The short arm of chromosome 17 is one of the most frequently affected chromosomal regions in lung cancers, while there is solid evidence that the p53 gene at 17p13.1 is a target for frequent 17p deletions. In the present study, we re-evaluated 17p deletions in lung cancers by conducting a detailed analysis of the minimum deleted region(s) on 17p with reference to the p53 gene status in each 100 primary lung cancer cases. In addition to the p53 locus at 17p13.1, the presence of an independent, commonly deleted region(s) at 17p13.3 was identified. Furthermore, loss of heterozygosity (LOH) at 17p13.3 was shown to be even more frequent than that at 17p13.1 and it appeared to occur in the absence of p53 mutation and/or 17p13.1 deletion. These results suggest that in addition to the p53 gene at 17p13.1, an as yet unidentified tumor suppressor gene(s) residing at 17p13.3 might play a role in lung carcinogenesis possibly in an earlier phase than the p53 gene. This would warrant future studies to identify the putative tumor suppressor gene at 17p13.3 in order to gain a better understanding of the molecular pathogenesis of this fatal disease. 相似文献
986.
Ultrasmall CdS particles, whose average size was controlled by thiols to range from 2 to 4 nm, were embedded in poly(vinyl alcohol) films. Shift of the fluorescence peak associates with the shift of the absorption threshold of the films, and the fluorescence intensity increases with the decrease in the size of CdS. Laser ablation at 308 nm was investigated by monitoring the emission spectra. Third-harmonic generation was measured for various sizes of CdS particles, and the optical nonlinearity in the nonresonance region was found to remain almost constant in the diameter range studied. © 1993 John Wiley & Sons, Inc. 相似文献
987.
988.
K. Fukui K. Okada Y. Inomata H. Takahashi S. Fujii Y. Fukawa K. Shirasawa 《Solar Energy Materials & Solar Cells》1997,48(1-4)
We have investigated the surface and bulk passivation technique on large-area multicrystalline silicon solar cells, a large open-circuit voltage has been obtained for cells oxidized to passivate the surface and hydrogen annealed after deposition of silicon nitride film on both surfaces by plasma CVD method (P---SiN) to passivate the bulk. The texture surface like pyramid structure on multicrystalline silicon surface has been obtained uniformly using reactive ion etching (RIE) method. Combining these RIE method and passivation schemes, the conversion efficiency of 17.1% is obtained on 15 cm × 15 cm multicrystalline silicon solar cell. Phosphorus diffusion, BSF formation, passivation technique and contact metallization for low-cost process sequence are also described in this paper. 相似文献
989.
Structural and electrochemical properties of LiNi1/3Co1/3Mn1/3O2: Calcination temperature dependence
Yasuhiro Fujii Hiroshi Miura Naoto Suzuki Takayuki Shoji Noriaki Nakayama 《Journal of power sources》2007
The structure of the layered LiNi1/3Co1/3Mn1/3O2 has been investigated by powder X-ray diffraction and electron diffraction, and the relationship of the calcination temperature with the crystal structure, morphology and electrochemical properties has been studied. All the unit cell parameters increase monotonically with increasing the calcination temperature. Some of the [00.1] zone electron diffraction patterns for the sample calcined at higher temperature than 1000 °C show extra spots indicating the 2 × 2 ordering in the basal triangular lattice. These results indicate that the high temperature calcination leads to the formation of vacancies in the transition metal layers with the spinel-like ordering. The calcination at higher temperature lowers the specific capacities and degrades the cycle performances, while the packing density of the powder is increased by the sintering. The optimum calcination temperature is 900 °C in order to obtain the electrochemically active and dense packed oxide particles. The decrease of Li composition leads to coprecipitation of the spinel-like second phase in the range of 0.742 ≤ x ≤ 0.884 for LixNi1/3Co1/3Mn1/3O2, when calcined at 900 °C. The Li-deficient samples show the worse electrochemical properties similarly to the stoichiometric samples calcined at high temperature. For the Li-excess samples, no impurity phase has been detected and their cycle performances are improved. 相似文献
990.
Vobornik I Manju U Fujii J Borgatti F Torelli P Krizmancic D Hor YS Cava RJ Panaccione G 《Nano letters》2011,11(10):4079-4082
Spin-based electronics in topological insulators (TIs) is favored by the long spin coherence(1,2) and consequently fault-tolerant information storage. Magnetically doped TIs are ferromagnetic up to 13 K,(3) well below any practical operating condition. Here we demonstrate that the long-range ferromagnetism at ambient temperature can be induced in Bi(2-x)Mn(x)Te(3) by the magnetic proximity effect through deposited Fe overlayer. This result opens a new path to interface-controlled ferromagnetism in TI-based spintronic devices. 相似文献