排序方式: 共有29条查询结果,搜索用时 15 毫秒
1.
Naoki Ichikawa Peter M. -Y. Chung Sohei Matsumoto Jun-ichi Matsumoto Naoki Takada 《Microgravity science and technology》2007,19(3-4):35-37
Ultrasound was applied to a micropipette micromixer to improve dispersion of gas and liquid in a microchannel. Flow visualization using a high-speed camera was performed to examine the effect of ultrasonic irradiation on bubble generation in the microchannel. Basically, nitrogen gas was injected using a (0.5 µm ID) glass micropipette into ethanol flowing in a rectangular (100 µm×200 µm) microchannel on polydimethylsiloxane (PDMS). Gas and liquid flow rates were regulated using mass flow controllers. At aflow condition that is typical of bubbly flow, ultrasound was transmitted into the microchannel using a piezo-electric (PZT) transducer over a range of operating voltages (2 to 200 Vp-p) and frequencies (50 to 60 kHz). Images captured during the action of the PZT transducer indicate that bubble formation is influenced by ultrasound. When subjected to ultrasound above 50 Vp-p and at the resonant frequency of the PZT transducer, bubbles formed that were smaller and closer together, signifying enhanced shearing of the gas at the micropipette tip by the liquid. The observation of gas slugs occurring sooner might be attributed to the coalescence of gas bubbles that became closely spaced. 相似文献
2.
Sohei Sato Hironori Hondoh Satoru Ueno 《Journal of the American Oil Chemists' Society》2021,98(3):269-280
Fat bloom in chocolate is a substantial problem that affects its sensory properties, such as texture and appearance. This phenomenon is because of diffuse light reflection on a roughened surface of chocolate, caused by structural changes of fat crystals subjected to various temperature conditions. The purpose of this study is to characterize the fat bloom formed through gradual two-step cooling after exposure to temperatures (35–37 °C) slightly above the cocoa butter Form βV melting point (33.8 °C). To clarify the fat bloom formation process, the structural changes in cocoa butter and on the chocolate surface, at the dynamic thermal condition for bloom formation, was investigated using X-ray diffraction (XRD), fluorescence light microscopy, and scanning electron microscopy (SEM). The results revealed that an entirely light brown fat bloom occurred, even in the absence of the Form βVI or other polymorphic transformation. Microscopic observation showed that the light brown appearance was because of the porous structure on the chocolate surface. This porous structure was formed by liquid oil moving inside of chocolate from the surface. The formation of a coarse network and the subsequent de-oiling, because of movement of unsolidified liquid fat into the chocolate, appeared to be the main causes of bloom formation. Therefore, a coarsened fat network and oil movement besides the conventional principles of polymorphic transformation of cocoa butter should be considered. 相似文献
3.
Terashima C Arihara K Okazaki S Shichi T Tryk DA Shirafuji T Saito N Takai O Fujishima A 《ACS applied materials & interfaces》2011,3(2):177-182
Conductive diamond whiskers were fabricated by maskless oxygen plasma etching on highly boron-doped diamond substrates. The effects of the etching conditions and the boron concentration in diamond on the whisker morphology and overall substrate coverage were investigated. High boron-doping levels (greater than 8.4 × 10(20) cm(-3)) are crucial for the formation of the nanosized, densely packed whiskers with diameter of ca. 20 nm, length of ca. 200 nm, and density of ca. 3.8 × 10(10) cm(-2) under optimal oxygen plasma etching conditions (10 min at a chamber pressure of 20 Pa). Confocal Raman mapping and scanning electron microscopy illustrate that the boron distribution in the diamond surface region is consistent with the distribution of whisker sites. The boron dopant atoms in the diamond appear to lead to the initial fine column formation. This simple method could provide a facile, cost-effective means for the preparation of conductive nanostructured diamond materials for electrochemical applications as well as electron emission devices. 相似文献
4.
The authors are developing a thermal jet dryer (TJD) with a vertical disc-shaped drying tank for the purpose of reducing the volume of solid wastes with high water content, such as organic sludges. In order to obtain the characteristics of air-particle multiphase flow in a TJD, cold model experiments and computational fluid dynamics (CFD) simulations were conducted. The following results were obtained: (1) A combined eddy was generated in the tank, such as in a cyclone separator. (2) “Cascading” phenomena occurred in the particle discharging mechanism. (3) In the TJD, particles maintained consistent drying conditions throughout the drying process. 相似文献
5.
Study on Drying Organic Sludges by Thermal Jet Dryer—Part 1: Drying Performance of Thermal Jet Dryer
The authors are developing a thermal jet dryer (TJD), with a vertical disc-shaped drying tank, for the purpose of weight and volume reduction of solid wastes with high water content, such as organic sludges. In order to obtain the drying performance of TJD, drying experiments using three kinds of solid wastes were carried out. The following results were obtained: (1) Drying performance depended most on the disintegration characteristics of sample. (2) There was little influence of the samples' properties on the gas–solid multiphase flow in the tank. (3) There was a critical feed rate at which the drying performance changed drastically. 相似文献
6.
Mizue Munekata Seiichi Kimura Hiroaki Kurishima Jinsuke Tanaka Sohei Yamamoto Hiroyuki Yoshikawa Kazuyoshi Matsuzaki Hideki Ohba 《热科学学报(英文版)》2008,17(1):56-60
Recently, development of high technology has been required for the formation of thin uniform film in manufacturing processes of semiconductor as the semiconductor instruments become more sophisticated. Spin coating is usually used for spreading photoresist on a wafer surface. However, since rotating speed of the disk is very high in spin coating, the dropped photoresist scarers outward and reattaches on the film surface. A catch cup is set up outside the wafer in spin coating, and scattered photoresist mist is removed from the wafer edge by the exhaust flow generated at the gap between the wafer edge and the catch cup. In the dry process of a spin coating, it is a serious concern that the film thickness increases near the wafer edge in the case of low rotating speed. The purpose of this study is to make clear the effect of the catch cup geometry on the 3D boundary layer flow over the wafer surface and the drying rate of liquid film. 相似文献
7.
Methods for the chemical recycling of polycarbonate (PC) wastes in the forms of bisphenol A (BPA) and cyclic heterocarbonates, such as 1,3‐dithiolan‐2‐one (DTO), 1,3‐dithiane‐2‐one (DTA), and cyclic unsymmetric heterocarbonates, were investigated to prove that PC can be utilized as a phosgene equivalent for industrial purposes. Treatment of PC pellets or waste PC compact discs with 1,2‐ethanedithiol and a catalytic amount of base (e.g., 1.5 mol % NaOH) in dioxane for a short period at 40°C produced DTO and BPA, both in nearly quantitative yields. The reaction could also be carried out in DTO, which saved the use of conventional solvents. Other cyclic heterocarbonates, that is, DTA, 1,3‐oxathiolan‐2‐one, 1,3‐thiazolidine‐2‐one, and N‐methyl‐1,3‐oxazolidine‐2‐one, were prepared in high yields under analogous conditions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2959–2968, 2003 相似文献
8.
The authors are developing a thermal jet dryer (TJD) with a vertical disc-shaped drying tank for the purpose of reducing the volume of solid wastes with high water content, such as organic sludges. In order to obtain the characteristics of air-particle multiphase flow in a TJD, cold model experiments and computational fluid dynamics (CFD) simulations were conducted. The following results were obtained: (1) A combined eddy was generated in the tank, such as in a cyclone separator. (2) “Cascading” phenomena occurred in the particle discharging mechanism. (3) In the TJD, particles maintained consistent drying conditions throughout the drying process. 相似文献
9.
Daniel S. Likius Hiroki Nagai Sohei Aoyama Chihiro Mochizuki Hiroki Hara Norio Baba Mitsunobu Sato 《Journal of Materials Science》2012,47(8):3890-3899
To find the percolation threshold for the electrical resistivity of metallic Ag-nanoparticle/titania composite thin films,
Ag-NP/titania composite thin films, with different volumetric fractions of silver (0.26 ≤ φAg ≤ 0.68) to titania, were fabricated on a quartz glass substrate at 600 °C using the molecular precursor method. Respective
precursor solutions for Ag-nanoparticles and titania were prepared from Ag salt and a titanium complex. The resistivity of
the films was of the order of 10−2 to 10−5 Ω cm with film thicknesses in the range 100–260 nm. The percolation threshold was identified at a φAg value of 0.30. The lowest electrical resistivity of 10−5 Ω cm at 25 °C was recorded for the composite with the Ag fraction, φAg, of 0.55. X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), and transmission electron microscopic
(TEM) evaluation of the effect of the morphology and the nanostructures of the Ag nanoparticles in the composite thin films
on the electrical resistivity of the film revealed that the films consist of rutile, anatase, and metallic Ag nanoparticles
homogeneously distributed in the titania matrix. It could be deduced that the electrical resistivity of the thin films formed
at 600 °C was unaffected by the anatase/rutile content within the thin film, whereas the shape, size, and separation distance
of the Ag nanoparticles strongly influenced the electrical resistivity of the Ag-nanoparticle/titania composite thin films. 相似文献
10.
Tashiro Masanori Sukenaga Sohei Ikemoto Koichi Shinoda Kozo Kajitani Tsuyoshi Suzuki Shigeru Shibata Hiroyuki 《Journal of Materials Science》2021,56(25):14170-14180
Journal of Materials Science - In practical applications of bismuth telluride thermoelectric materials, the materials need to be connected with a metallic electrode before they can be used;... 相似文献