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Search Results: 1 - 10 of 708 matches for " Toshihiro Okabe "
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Evaluation of Sawdust and Rice Husks as Fillers for Phenolic Resin Based Wood-Polymer Composites  [PDF]
Marieme Josephine Lette, Elhadji Babacar Ly, Diene Ndiaye, Akito Takasaki, Toshihiro Okabe
Open Journal of Composite Materials (OJCM) , 2018, DOI: 10.4236/ojcm.2018.83010
Abstract: We produced Wood-Polymer Composites (WPCs) with phenolic resin (PR) filled with saw dust (SD) and rice husks (RH) in a PR:fillerratio of 60:40 wt.%. RH and SD were grinded and sieved into particles <160 μm. The aim of this research work was to evaluate sawdust and rice husks as fillers for sustainable phenolic resin based WPCs. Therefore, we investigated the thermal stability of PR/RH and PR/SD WPCs then we studied and compared the tensile, flexural properties of PR/SD and PR/RH WPCs samples, as well as their dimensional stability after water absorption test. Furthermore, through ultraviolet light exposure, we evaluated the effects of photo-oxidation on the water stability and mechanical properties of PR/RH and PR/SD WPCs samples compared to unexposed ones. PR filled with SD presented better mechanical properties compared to PR/RH WPCs samples. However, PR/RH WPCs showed good mechanical properties, and better thermal resistance and better water repulsion capabilities compared to PR/SD WPCs samples. Although, long time UV exposure ended up lowering considerably the mechanical properties and water resistance of PR/SD and PR/RH WPCs, both RH and SD offer great added value as fillers for PR based WPCs; SD having better interactions with PR matrix compared to RH.
Application of Monte Carlo Method to Phase Separation Dynamics of Complex Systems
Yutaka Okabe,Tsukasa Miyajima,Toshiro Ito,Toshihiro Kawakatsu
Physics , 1999, DOI: 10.1142/S0129183199001297
Abstract: We report the application of the Monte Carlo simulation to phase separation dynamics. First, we deal with the phase separation under shear flow. The thermal effect on the phase separation is discussed, and the anisotropic growth exponents in the late stage are estimated. Next, we study the effect of surfactants on the three-component solvents. We obtain the mixture of macrophase separation and microphase separation, and investigate the dynamics of both phase separations.
E-Cadherin-Coated Plates Maintain Pluripotent ES Cells without Colony Formation
Masato Nagaoka, Uichi Koshimizu, Shinsuke Yuasa, Fumiyuki Hattori, Hao Chen, Tomofumi Tanaka, Masaru Okabe, Keiichi Fukuda, Toshihiro Akaike
PLOS ONE , 2006, DOI: 10.1371/journal.pone.0000015
Abstract: Embryonic stem (ES) cells cultured on gelatin-coated plates or feeder layers form tight aggregated colonies by the E-cadherin-mediated cell-cell adhesions. Here we show that murine ES cells do not make cell-cell contacts or form colonies when cultured on the plate coated with a fusion protein of E-cadherin and IgG Fc domain. The cells in culture retain all ES cell features including pluripotency to differentiate into cells of all three germ layers and germ-line transmission after extended culture. Furthermore, they show a higher proliferative ability, lower dependency on LIF, and higher transfection efficiency than colony-forming conditions. Our results suggest that aggregated colony formation might inhibit diffusion of soluble factors and increase cell-cell communication, which may result in a heterogeneous environment within and between surrounding cells of the colony. This method should enable more efficient and scalable culture of ES cells, an important step towards the clinical application of these cells.
Fairness Norms and the Incidence of Environmental Subsidy  [PDF]
Toshihiro Uchida
Modern Economy (ME) , 2012, DOI: 10.4236/me.2012.36100
Abstract: Although fairness concerns are frequently discussed in the real world environmental politics, their effects are relatively neglected in the environmental economics literature. Using a survey method, this paper attempts to reveal how fairness norms affect the incidence of subsidy both in the short-run and long-run. The results indicate that statutory incidence (legal right to receive subsidy) affects people’s fairness norms on who should receive subsidy. In particular it is considered unfair for a firm to receive a part of the subsidy when it is legally granted to the consumer side. If firms avoid behaviors that are considered unfair, the tax and subsidy equivalence theorem may not hold under this situation. The survey results also reveal that fairness norms affect the incidence of subsidy in the long-run, in a sense that the allocation of gains that are generated due to subsidy is affected. People find it fair if allocation is made in proportion to firms’ own effort. Therefore, if an increase in profit is achieved by activities directly supported by subsidy, people find it less justifiable for firms to keep all the gains by themselves and thus firms may be forced to share the gains with consumers.
Solvent-Induced Phase-Inversion and Electrical Actuation of Dielectric Copolymer Films  [PDF]
Yeonju Jang, Toshihiro Hirai
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.23023
Abstract: Block copolymers posses inherently the ability of form a variety of phase-separated microdomain structures. The lengths of block segments and the selectivity of the solvent are primary factors affecting the resultant morphology. This paper investigated the effect of casting solvents on the morphologies and electrical actuation of poly(methyl methacrylate)-poly(n-butyl acrylate)-poly(methyl methacrylate) (PMMA-PnBA-PMMA) triblock copolymer films comprising PMMA hard segment and PnBA soft segment. Transmission electron microscopy and confocal laser scanning microscopy observation revealed that PMMA and PnBA segments were assembled into various micro- and nano-sized phase structures where either of them formed continuous phase. This implies that continous phase could be inversed by used casting solvents. Solvent-dependent phase morphologies had a significant effect on the electrical actuation results. Increase of the PnBA contents and the continuous phases of PnBA soft segments improved both of electrical actuation and dielectric constant, indicating that solvent-induced phase separation modulates the electrical actuation of dielectric films. The significance of the role of solvent selectivity and the major continuous phase of the polymer in defining the morphology and electrical actuation of the self-assembled block copolymer structure are discussed.
Development of Battery-Less Wireless Current Sensor Node Utilizing Charging Time of Capacitors with Wide Measurement Range  [PDF]
Hironao Okada, Toshihiro Itoh
Wireless Sensor Network (WSN) , 2013, DOI: 10.4236/wsn.2013.511026

We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends on the current flowing through a power line. In the case that the node transmits data every time when voltage of the capacitor exceeds a threshold voltage, we can indirectly measure the current by measuring the transmission intervals. In this method, the circuit of the node can be simplified and power consumption for the wireless transmission can be decreased because the measured current data does not need to be included in the transmitted packet. However, the measurable range is about single digit because the transmission interval decreases suddenly as the current increases. In this work, we have ex- panded the range using one CT, one wireless transmission module, and two charging circuits that include different load resistors connected in series. The results indicated that the measurable range was from 0.5 A to 50 A.

M-ary FSK Modulation Using Short Packet without a Preamble and Error Detection Codes for Low Power Wireless Communication  [PDF]
Hironao Okada, Toshihiro Itoh
Wireless Sensor Network (WSN) , 2014, DOI: 10.4236/wsn.2014.63005
Abstract: Since power of a wireless sensor node is limited, low power communication technology has been required. M-ary frequency shift keying (MFSK) modulation with orthogonal signals is one of the methods to decrease the power. However, if the amount of transmitted data including such as an identification number (ID) of a node and measured data is small, a ratio of the data length to the total packet length, which means transmission efficiency, becomes quite low. Because a preamble and error check codes are generally added to a packet for synchronization between a transmitter and a receiver and for decrease in reception errors, respectively. In this research, we have developed a method with digital filters which eliminates the other signals from time series frequency spectra not to use a preamble and error check codes. Although estimated synchronization loss of the method was less than 1.6 dB, it was found that the loss of the method on error packet rate was almost 0 dB at more than 0.001 of packet error rate by a simulation made by BASIC. These results indicate a possibility to realize that a packet which consists of only two symbols can be received with no error if the transmitted data is less than 14 bits using 128-FSK.
The Ventral Ascending Noradrenergic Bundles Are Involved in the Stress Response to Immobilization in Rats  [PDF]
Toshihiro Yoshihara, Yasutaka Yawaka
Journal of Behavioral and Brain Science (JBBS) , 2015, DOI: 10.4236/jbbs.2015.53008
Abstract: Stressful stimuli induced by immobilization are perceived as acute stress in rats. This acute stress activates corticotropin-releasing hormone (CRH) neurons in the hypothalamic paraventricular nucleus (PVN), resulting in stimulation of the hypothalamic-pituitary-adrenal (HPA) axis. The ventral ascending noradrenergic bundles (V-NAB) from the brainstem innervate the PVN. To investigate the relationship between the response of the HPA axis and the V-NAB, we examined changes in plasma corticosterone, the final output of the HPA axis, and extracellular noradrenaline (NA) in the PVN following immobilization stress in rats that received bilateral 6-hydroxydopamine (6-OHDA) lesions of the V-NAB. 6-OHDA microinjection into the V-NAB reduced the magnitude of the responses of plasma corticosterone and extracellular NA in the PVN following immobilization stress. Our results suggest that V-NAB innervation of the PVN is involved in immobilization stress-induced activation of the HPA axis.
Restricted Daily Feeding of Liquid Meal Reduces the Motivation of Rats to Get Food  [PDF]
Toshihiro Yoshihara, Yasutaka Yawaka
Journal of Behavioral and Brain Science (JBBS) , 2015, DOI: 10.4236/jbbs.2015.54013
Abstract: To corroborate the hypothesis that mastication affects the motivation to get food, we examined the effects of dietary consistency on the development of meal anticipation in locomotor activity of rats subjected to restricted daily feeding (RF), in which food supply was restricted to a fixed time each day. RF of both liquid and solid meals produced anticipatory locomotor activity. However, the strength of the activity in rats subjected to RF of liquid meal was lower than that in rats subjected to RF of solid meal. These results suggest that the feeding-associated circadian oscillation that developed by feeding with liquid meal is less potent than that in the case of feeding with solid meal. Furthermore, mastication for digesting solid meal might be one of the factors that determine the strength of the feeding-associated circadian oscillation.
Electrical Conductivity of Fermi Liquids. II. Quasiparticle Transport
Takuya Okabe
Physics , 1998, DOI: 10.1143/JPSJ.67.4178
Abstract: We develop a general theory of Fermi liquids to discuss the Kadowaki-Woods relation $A\propto \gamma^2$. We derive a formula for the ratio $A/\gamma^2$ which is expressed as a product of two dimensionless parameters $\alpha$ and $F$, where $\alpha$ represents a coupling constant for quasiparticle scattering and $F$ is a geometric factor determined by the shape of the Fermi surface. Then we argue that the universal ratio observed in heavy fermion compounds is reproduced under the conditions $\alpha\sim 1$ and $F\sim 20$. The former is regarded as a universality of Fermi liquids in a strong coupling regime, and the latter is corroborated by evaluating $F$ definitely in simple cases. It is noted that the proportional relation is just an example of the universal phenomena to be expected for the whole class of strong coupling Fermi liquids.
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