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61.
Masanori Hirano Keisuke Ota Takaharu Ito 《Journal of the American Ceramic Society》2005,88(12):3303-3310
Anatase-type TiO2 powder containing sulfur with absorption in the visible region was directly formed as particles with crystallite in the range 15–88 nm by thermal hydrolysis of titanium(III) sulfate (Ti2 (SO4 )3 ) solution at 100°–240°C. Because of the presence of ammonium peroxodisulfate ((NH4 )2 S2 O8 ), the yield of anatase-type TiO2 from Ti2 (SO4 )3 solution was accelerated, and anatase with fine crystallite was formed. Anatase-type TiO2 doped with ZrO2 up to 9.8 mol% was directly precipitated as nanometer-sized particles from the acidic precursor solutions of Ti2 (SO4 )3 and zirconium sulfate in the presence and the absence of (NH4 )2 S2 O8 by simultaneous hydrolysis under hydrothermal conditions at 200°C. By doping ZrO2 into TiO2 and with increasing ZrO2 content, the crystallite size of anatase was decreased, and the anatase-to-rutile phase transformation was retarded as much as 200°C. The anatase-type structure of ZrO2 -doped TiO2 was maintained after heating at 1000°C for 1 h. The favorable effect of doping ZrO2 to anatase-type TiO2 on the photocatalytic activity was observed. 相似文献
62.
Poly(L ‐lactic acid) (PLLA: Mw = 19.4 × 104)/poly(ethylene glycol) (PEG: Mw = 400) blend films were formed by use of a solvent‐cast technique. The properties and structures of these blend films were investigated. The Young's modulus of the PLLA decreased from 1220 to 417 MPa with the addition of PEG 5 wt %, but the elongation at break increased from 19 to 126%. The melting point of PLLA linearly decreased with increases in the PEG content (i.e., pure PLLA: 172.5°C, PLLA/PEG = 60/40 wt %: 159.6°C). The PEG 20 wt % blend film had a porous structure. The pore diameter was 3–5 μm. The alkali hydrolysis rate of this blend film was accelerated due to its porous structure. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 965–970, 2004 相似文献
63.
Thermal spray of Ni-Cr and Al coatings was attempted on modified 9Cr-1Mo steel, to evaluate their steam oxidation resistance. Atmospheric plasma spray (APS) coatings of 50Ni-50Cr as undercoat and Al topcoat were attempted with the aim that the pores produced by 50Ni-50Cr undercoat can be filled with Al topcoat during the steam oxidation. The steam oxidized samples evinced the Ni and Cr diffusion towards the Al coating structure and changed the topcoat in to the Ni-Al intermetallics. Though the two-layered coating exhibited an excellent performance against the steam oxidation for the base steel substrate till 3000 h of test, the top layers of the coating underwent significant internal oxidation. 相似文献
64.
An extraordinary impedance-step phenomenon of GMI (giant magnetoimpedance) effect was studied. It is observed for a thin-film GMI element with an inclined magnetic stripe domain. The “inclined stripe domain” means a domain structure that has inclined domain walls against the width direction of the GMI strip. An observation of magnetic domain reveals that a sudden change of domain structure, such as stripe-domain vanishing or occurrence, happens simultaneously with the impedance step. A theoretical consideration, based on the bias-susceptibility model of a single-domain magnetic thin film with uniaxial anisotropy, qualitatively shows that the existence of an inclined stripe domain makes the impedance lower than that characteristic of a single-domain structure. 相似文献
65.
To testify to the advantage of large ceramic powder spraying, numerical simulations and experimental studies on the behavior
of large yttria-stabilized zirconia (YSZ) powder in a high-power hybrid plasma spraying process have been carried out. Numeric
predictions and experimental results showed that, with the high radio frequency (RF) input power of 100 kW, the most refractory
YSZ powder with particle sizes as large as 88 μm could be fully melted and well-flattened splats could be formed. A large
degree of flattening (ξ) of 4.7 has been achieved. The improved adhesive strength between the large splat and the substrate
was confirmed based on the measurement of the crack density inside of the splats. A thick YSZ coating >300 μm was successfully
deposited on a large CoNiCrAlY-coated Inconel substrate (50×50×4 mm in size). The ultradense microstructure without clear
boundaries between the splats and the clean and crack-free interface between the top-coat and the bond-coat also indicate
the good adhesion. These results showed that highpower hybrid plasma spraying of large ceramic powder is a very promising
process for deposition of highquality coatings, especially in the application of thermal barrier coatings (TBCs). 相似文献
66.
Creep lives of high Cr ferritic heat resisting steel weldments decrease due to Type Ⅳ fracture, which occurs as a result of formation and growth of creep voids and cracks on grain boundaries in fine-grained heat affected zone (HAZ). Because boron is considered to suppress the coarsening of grain boundary precipitates and growth of creep voids, we have investigated the effect of boron addition on the creep properties of 9Cr steel weldments. Four kinds of 9Cr3WSCoVNb steels with boron content varying from 4.7×10-5 to 1.8×10-4 and with nitrogen as low as 2.0×10-5 were prepared. The steel plates were welded by gas tungsten arc welding and crept at 923K. It was found that the microstructures of HAZ were quite different from those of conventional high Cr steels such as P91 and P92, namely the fine-grained HAZ did not exist in the present steel weldments. Boron addition also has the effect to suppress coarsening of grain boundary carbides in HAZ during creep. As a result of these phenomena, the welded join 相似文献
67.
Ryoichi Kawahara Tetsuya Takine Tatsuya Mori Noriaki Kamiyama Keisuke Ishibashi 《Computer Networks》2013,57(6):1560-1576
We consider the mean–variance relationship of the number of flows in traffic aggregation, where flows are divided into several groups randomly, based on a predefined flow aggregation index, such as source IP address. We first derive a quadratic relationship between the mean and the variance of the number of flows belonging to a randomly chosen traffic aggregation group. Note here that the result is applicable to sampled flows obtained through packet sampling. We then show that our analytically derived mean–variance relationship fits well those in actual packet trace data sets. Next, we present two applications of the mean–variance relationship to traffic management. One is an application to detecting network anomalies through monitoring a time series of traffic. Using the mean–variance relationship, we determine the traffic aggregation level in traffic monitoring so that it meets two predefined requirements on false positive and false negative ratios simultaneously. The other is an application to load balancing among network equipments that require per-flow management. We utilize the mean–variance relationship for estimating the processing capability required in each network equipment. 相似文献
68.
Tetsushi Oka Toyokazu Abe Kaoru Sugita Masao Yokota 《Artificial Life and Robotics》2009,13(2):455-459
This article describes a multimodal command language for home robot users, and a robot system which interprets users’ messages
in the language through microphones, visual and tactile sensors, and control buttons. The command language comprises a set
of grammar rules, a lexicon, and nonverbal events detected in hand gestures, readings of tactile sensors attached to the robots,
and buttons on the controllers in the users’ hands. Prototype humanoid systems which immediately execute commands in the language
are also presented, along with preliminary experiments of faceto-face interactions and teleoperations. Subjects unfamiliar
with the language were able to command humanoids and complete their tasks with brief documents at hand, given a short demonstration
beforehand. The command understanding system operating on PCs responded to multimodal commands without significant delay.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
69.
Toshihide Miyagi Norihiro Abe Yoshimasa Kinoshita Tatsushi Tokuyasu Hirokazu Taki Shoujie He 《Artificial Life and Robotics》2009,14(2):237-241
In this article, a system is proposed for a simulated operation which would help a trainee surgeon to perform a medical operation
to ensure that a cerebral aneurysm does not burst. The physician will have acquired empirical medical technologies from operations
in traditional clinical teaching. However, there is a problem with safety and the burden to the patient. Therefore, recently
a new training approach for a simulated medical operation using virtual reality has been explored. With the aim of developing
a simulated system for a medical operation for a cerebral aneurysm, we considered the necessary functions such as detecting
the brain aneurysm that is the target of the operation, and searching for a suitable blood vessel to make a plan for the operation. 相似文献
70.
Yuki Takenaka Norihiro Abe Yoshihiro Tabuchi Hirokazu Taki Shoujie He 《Artificial Life and Robotics》2009,14(2):224-227
This research was aimed at making a robot that can go and get an object designated by the user. We produced a robot control
system that uses pointing and voice control. This control system is composed of two systems. One system is the object instruction
system that uses pointing, and the other is the object instruction system that uses voice. The approximate position of a designated
object is recognized by the object instruction system that uses pointing, and information about the object and instructions
about the operation are conveyed by the object instruction system that uses voice. This time, the object instruction system
that uses pointing has been designed and verified as the first step. A calculation resource to calculate the approximate position
of the designated object is obtained when the user points directly at the object. A robot can be moved around a designated
object by using this system. The object instruction system that uses voice will be constructed in future work. 相似文献