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71.
Yutaka Kawahara Atsushi Nakayama Masatoshi Shioya Masaki Tsuji Hideki Yamane Tadahisa Iwata 《Journal of Materials Science》2012,47(4):1887-1892
Structure of poly(dioxanone) (PPDX) fibers produced through a two-step melt-spinning process with an additional short-period
annealing above the melting temperature of PPDX was investigated and the effect of annealing on the degradation behavior was
discussed. The morphological study carried out by etching the fibers using a phosphate or permanganate solution suggested
that the fibers take a skin–core structure, and both the skin layer and the core region consist of a bundle of microfibrils.
The micro-beam X-ray diffraction analysis revealed that the short-period annealing in the production process only slightly
promotes the crystallization in the skin layer but contributes to increasing the packing of amorphous chains near the skin,
which seems to be the controlling factor of the hydrolytic degradation behavior of the fibers. 相似文献
72.
Yosuke Ue Ryoichi Hara Hiroyuki Kita Yutaka Saito Katsuyuki Takitani Masami Saito 《Electrical Engineering in Japan》2012,180(3):55-63
Photovoltaic (PV) systems are attracting attention as one of the promising countermeasures against global warming and the environmental issues. However, the generation output from PV systems is generally unstable and unpredictable. Therefore, large penetration of PV systems may cause some serious impacts on power system operation, such as load frequency control, voltage regulation, etc. Estimation of the influences of PV system installation is becoming important, but it requires simultaneous multipoint solar radiation measurements. The Japan Meteorological Business Support Center has provided 1‐minute meteorological data observed in Japan, but its solar radiation data includes quantization errors. This paper proposes a regeneration method for solar radiation data including quantization errors. It also analyzes the spatial smoothing effect of global solar radiation fluctuations. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(3): 55–63, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21274 相似文献
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75.
Daisuke Kawashima Yutaka Asako 《International Journal of Heat and Mass Transfer》2012,55(9-10):2244-2248
This paper focuses on temperature rise due to the viscous dissipation in liquids flowing through micro-channels. In the past, equations for the prediction of the temperature rise have been obtained as a function of the friction factor, Reynolds number and Eckert number or a similar form, starting from Navier–Stokes equation and energy equation under the assumption of fully developed laminar flow by researchers. The temperature rises calculated from the equations have been compared with experimental data and the equations have been validated. However, in this paper, a new equation for the prediction of the temperature rise is simply obtained from the first law of thermodynamics without restriction of fully developed laminar flow. 相似文献
76.
Kazushige Ishida Yoichi Wada Masahiko Tachibana Nobuyuki Ota Motohiro Aizawa 《Journal of Nuclear Science and Technology》2013,50(11):1071-1082
The effects of water chemistry distribution on the potential of a reference electrode and of the potential distribution on the measured potential should be known qualitatively to obtain accurate electrochemical corrosion potential (ECP) data in BWRs. First, the effects of oxygen on a platinum reference electrode were studied in 553 K pure water containing dissolved hydrogen (DH) concentration of 26–105 μg kg?1 (ppb). The platinum electrode worked in the same way as the theoretical hydrogen electrode under the condition that the molar ratio of DH to dissolved oxygen (DO) was more than 10 and that DO was less than 100 ppb. Second, the effects of potential distribution on the measured potential were studied by using the ECP measurement part without platinum deposition on the surfaces connected to another ECP measurement part with platinum deposition on the surfaces in 553 K pure water containing 100–130 ppb of DH or 100–130 ppb of DH plus 400 ppb of hydrogen peroxide. Measured potentials for each ECP measurement part were in good agreement with literature data for each surface condition. The lead wire connecting point did not affect the measured potential. Potential should be measured at the nearest point from the reference electrode in which case it will be not affected by either the potential distribution or the connection point of the lead wire in pure water. 相似文献
77.
Midori Takasaki Kentaro Hara Yutaka Ohkoshi Takayuki Fujii Hiroyasu Shimizu Masaharu Saito 《Polymer Engineering and Science》2014,54(11):2605-2609
Thermoplastic polyurethane fiber webs were prepared using a laser‐heated electrospinning process combined with air blowing. The effect of spinning conditions such as air flow rate and air temperature on fiber diameter and molecular weight was investigated. Although the average fiber diameter decreased with increased air flow rate at each air temperature, the diameter increased when the air flow rate was >15 NL min?1. In addition, the fiber was comparatively thicker with an increase in the air temperature. The variation in the fiber diameter tends to increase with the air flow rate, and a reduction in the molecular weight of the fiber by thermal degradation was suppressed. The thinnest and most uniform fiber with a diameter of 0.9 µm and a diameter coefficient variation of 15% was obtained at an air temperature of 25°C under an air flow rate of 15 NL min?1. This fiber also had a minimum of decreased molecular weight. POLYM. ENG. SCI., 54:2605–2609, 2014. © 2013 Society of Plastics Engineers 相似文献
78.
Hydrogen and carbon dioxide adsorption with tetra‐n‐butyl ammonium semi‐clathrate hydrates for gas separations 下载免费PDF全文
Hiroyuki Komatsu Masaki Ota Yoshiyuki Sato Masaru Watanabe Richard L. Smith Jr. 《American Institute of Chemical Engineers》2015,61(3):992-1003
Gas adsorption rates of H2, CO2, and H2‐CO2 gas mixture (H2/CO2 = 3.4) with tetra‐n‐butyl ammonium salt (bromide, chloride, and fluoride) semi‐clathrate hydrate particles were measured at 269 K to assess their properties for gas separation. Equilibrium gas occupancies in the S‐cages of the particles were in order of (high to low) for hexagonal structure‐I, tetragonal structure‐I, and superlattice of cubic structure‐I structures with the maximum fractional occupancy by CO2 being about 40%. The CO2 diffusion rate depended on the anion size of the salt, which is attributed to distortion of the S‐cage that is close to the molecular size of CO2. Simulations of semi‐clathrate hydrate particles with theory showed that H2/CO2 selectivities could be as high as 36 (3.0 mol% TBAF) and that selectivities for an ideal membrane (3.3 mol% TBAF) could be >100 (269 K, 0.3–4.5 MPa). Semi‐clathrate hydrates have wide application as separation media for gas mixtures. © 2014 American Institute of Chemical Engineers AIChE J, 61: 992–1003, 2015 相似文献
79.
Structure and mechanical properties of multi‐hollowed fibers produced by CO2 laser irradiated neck drawing 下载免费PDF全文
Young‐Ah Kang Xin Zhao Yutaka Ohkoshi Kyoung Hou Kim 《Polymer Engineering and Science》2016,56(6):609-616
Multi‐hollowed fibers with a hollowness ratio of over 20% were successfully produced using a neck‐drawing technique accompanied by CO2 laser irradiation on unoriented and amorphous polytrimethylene terephthalate (PTT) fibers with diameters of approximately 104 µm. The structure and mechanical properties of the multi‐hollowed fibers were characterized using scanning electron microscopy, wide angle X‐ray diffraction (WAXD), birefringence measurements, and tensile tests. Crystal orientation factors in the direction normal to the (010) and (002) planes, which were obtained from WAXD patterns, were lower in comparison to values obtained in previous studies on fibers that did not feature these hollows [9] because of the development of these internal hollows. The PTT fibers in this study also displayed high toughness, about 465 MPa (3.5 cN/dtex) strength and about 40% elongation, and had excellent elastic recovery (>95%) after 10 stretch cycles. POLYM. ENG. SCI., 56:609–616, 2016. © 2015 Society of Plastics Engineers 相似文献
80.
Patrick Walther Antje Ota Alexander Müller Frank Hermanutz Frank Gähr Michael R. Buchmeiser 《大分子材料与工程》2016,301(11):1337-1344
Chitin and its deacetylated derivative, chitosan, are nontoxic, antibacterial, biodegradable, and biocompatible biopolymers. Due to these properties, they are widely used for biomedical applications such as scaffolds for tissue engineering, wound dressings, separation membranes and antibacterial coatings. Unfortunately, there is still a lack of suitable solvent systems for the direct processing of chitin, e.g., into films and coatings. Such solvents must be nontoxic, noncorrosive, nondegrading, and allow for high chitin concentrations. Here, the potential of designed ionic liquids (IL) as solvents for chitin is outlined. Phosphonium‐ and imidazolium‐based ILs are synthesized, characterized and the influence of the cation on the solution process has been evaluated. It is shown that particularly imidazolium carboxylate‐based ILs are appropriate solvents for chitin and are suitable for the production of foils and coatings on both fabrics and foams.