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71.
Si photonics becomes one of the research focuses in the field of photonics.Si-based light-emitting devices are one of the most important devices in this field.In this paper,we review the Si-based light... 相似文献
72.
ABSTRACT: Forming electrodes on opposite sides of an individual bismuth nanowire was attempted to prepare for Hall measurements. Although a 1-mm-long bismuth nanowire which is completely covered with a quartz template has been successfully fabricated to prevent oxidation, it is very difficult to attach Hall electrodes on the opposite sides of the nanowire due to the quartz covering. One side of the cylindrical quartz template was removed by polishing without exposure of the nanowire to the atmosphere; the thickness between the polished template surface and the nanowire was estimated to be several micrometers. Focused ion beam processing was successfully employed to expose both surfaces of the nanowire under high vacuum by removing part of the quartz template. A carbon thin film was then deposited in situ on the wire surface to fabricate an electrical contact on the bismuth nanowire sample. Furthermore, the energy dispersive X-ray analysis was performed to the area processed by focused ion beam, and the bismuth component of the nanowire was successfully detected. It was confirmed that the focused ion beam processing was applicable to attach electrodes to bismuth nanowire for Hall measurement. 相似文献
73.
Yasuhiro Yogo Michiaki Kamiyama Takamichi Iwata Noritoshi Iwata Takashi Ishikawa 《Metallurgical and Materials Transactions A》2012,43(3):893-899
In this article, the isothermal flow stress in supercooled austenite was measured for a high hardenability steel. Supercooled
austenite forms at the nonequilibrium phase and changes into other phases within a short time. It was confirmed that conventional
tensile tests, which require maintaining a constant temperature before stretching, cannot accurately measure the flow stress
in supercooled austenite. Therefore, a new tensile test named “the continuous cooling tensile test” was developed. In this
test, stretching is conducted during continuous cooling. In the continuous cooling tensile test, the flow stress between 673 K
and 973 K (400 °C and 700 °C) was measured. Microscopic observations of the continuous cooling test results verified that
the microstructures were supercooled austenite. 相似文献
74.
75.
Masahiko Hayashi Kazuya Yoshimoto Naohito Hirata Kiyoshi Tanaka Nobuki Oguni Katsumasa Harada Akio Matsushita Yasuhiro Kawachi Hiroshi Sasaki 《Israel journal of chemistry》2001,41(4):241-246
Highly enantioselective addition of diketene to aldehydes was achieved by using novel Schiff base—titanium alkoxide complexes. Up to 92% ee of 5-hydroxy-3-oxoesters was obtained. This procedure provides an efficient method for the asymmetric synthesis of potential inhibitors of HMG coenzyme reductase. 相似文献
76.
We have characterized the binary LB films of merocyanine dye (MS) and arachidic acid (C20) before and after hydrothermal treatment (HTT), which is defined as a heat treatment under relative humidity of 100%, focusing on the morphology studied by bright field (BF) microscopy and fluorescence (FL) microscopy. BF microscopy observation has revealed that the as-deposited MS-C20 binary LB film is found to emit intense red fluorescence over the whole film area by 540-nm excitation. Since the surface image is almost featureless, it is considered that the crystallite sizes of J-aggregate are less than 10 μm. Interestingly, after HTT, round-shaped domains are observed in the LB systems, and the sizes are reaching 100 μm in diameter. Crystallites of J-aggregate, which are bluish in color and emit intense red fluorescence, tend to be in the round domains. We have observed two different types of domains, i.e., blue-rimmed domains and white-rimmed domains, which are postulated to be confined in the inner layers and located at the outermost layer, respectively. The thickness of the domains is equal to or less than that of the double layer of the MS-C20 mixed LB film, which is ca. 5.52 nm. The molecular order of MS in the J-aggregate is improved by the HTT process leading to the significant sharpening of the band shape together with the further red shift of the band (from 590 to 594 nm up to 597 to 599 nm). The reorganized J-band is considered to be ‘apparently’ isotropic owing to the random growth of the J-aggregate in the film plane. We consider that the lubrication effect by the presence of water molecules predominates in the HTT process. 相似文献
77.
Thermal Stability,Optical Transmittance,and Refractive Index Dispersion of La2O3–Nb2O5–Al2O3 Glasses
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Kohei Yoshimoto Atsunobu Masuno Hiroyuki Inoue Yasuhiro Watanabe 《Journal of the American Ceramic Society》2015,98(2):402-407
La2O3–Nb2O5–Al2O3 high‐refractive‐index glasses were fabricated by containerless processing, and the glass‐forming region was determined. The thermal stability, density, optical transmittance, and the refractive index dispersion of these glasses were investigated. All the glasses were colorless and transparent in the visible to near infrared (NIR) region and had high refractive index with low wavelength dispersion. Some of these glasses were found to have significantly high glass‐forming ability. These results indicate that the ternary glasses are suitable for optical applications in the visible to NIR region. The effects of the substitution of Al2O3 for Nb2O5 on optical properties were discussed on the basis of the Drude–Voigt equation. It was suggested that the substitution of Al2O3 for Nb2O5 increased the molecular density and suppressed a decrease in the refractive index, even when both the average oscillator strength and inherent absorption wavelength decreased in La2O3–Nb2O5–Al2O3 glasses. These results are helpful for designing new optical glasses controlled to have a higher refractive index and lower wavelength dispersion. 相似文献
78.
提出了含黏粒砂土模型地基制备、饱和与均匀性监测技术,利用ZJU-400土工离心机振动台开展了相同相对密度含黏粒砂土(黏粒含量10%)和洁净砂的地震液化模型试验,再现了水平场地地震液化现象,揭示了含黏粒砂土场地液化灾变特点。弯曲元波速监测表明,模型制备均匀性良好,相同条件下含黏粒砂土剪切波速比洁净砂低。而根据超静孔压消散与固结沉降观测分析发现,含黏粒砂土渗透系数比洁净砂低一个数量级,从而影响其液化前后超静孔压响应和应力应变行为。渗透性差异导致模型内超静孔压产生模式和消散速率显著不同,振动时含黏粒砂土模型浅层超静孔压累积比洁净砂慢,而深层则相反;震后含黏粒砂土孔压消散时间是洁净砂的15倍。液化过程中含黏粒砂土剪应力应变响应比相同深度处的洁净砂更显著,液化后其滞回圈应变较大、割线模量较小且阻尼比较大。土体液化沉降主要发生在液化后超静孔压消散过程,含黏粒砂土模型超静孔压消散时间更长,沉降量更大。上述成果为进一步研究含黏粒砂土地震响应分析及其液化判别提供了科学依据。 相似文献
79.
Copolymerization is a useful way of modifying the physical properties of a material to meet specific needs, but it can result in a significant light scattering loss due to dielectric fluctuations in the material. Ideal random copolymers are known to be more transparent; however, the light-scattering properties of such copolymers in bulk have not been fully studied. In this paper, two representative ideal random copolymers were synthesized: methyl methacrylate (MMA)/benzyl methacrylate (BzMA) and MMA/2,2,2-trifluoroethyl methacrylate (TFEMA). The effects of copolymer composition and polymerization temperature on the light-scattering properties were investigated. Polarized light scattering (VV) in copolymers was more sensitive to the polymerization temperature. Higher temperatures were necessary to homogenize the dielectric fluctuations and minimize excess light scattering. However, once the heterogeneous structures vanished, the copolymer bulk exhibited low scattering losses, which are comparable with homopolymers, over the entire range of copolymer compositions. 相似文献
80.
Efficient gas recovery and separation in a hydrate-based system was investigated for a model gaseous mixture of R22 and nitrogen. The formed hydrate settled in the recovery vessel; excess water was recycled and the hydrate was subsequently decomposed by releasing pressure from the vessel. The gas uptake rate of R22 gas from the vapor phase and the gas recovery rate from the hydrate were determined from hydrate formation and decomposition, respectively. The gas recovery rate of R22 gas gradually increased with time. On the contrary, the nitrogen gas recovery rate was a maximum in the initial stage of hydrate decomposition. A high separation factor (S.F.) was achieved by first separating the N2-rich gas generated during initial hydrate decomposition. An efficient hydrate-based gas separation and recovery process is proposed. 相似文献