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501.
Komaba S Ishikawa T Yabuuchi N Murata W Ito A Ohsawa Y 《ACS applied materials & interfaces》2011,3(11):4165-4168
Fluoroethylene carbonate is an efficient electrolyte additive to improve the reversibility of electrochemical sodium insertion for hard-carbon and NaNi(1/2)Mn(1/2)O(2) electrodes in aprotic Na cells. The additive is also capable of the electrochemical deposition/dissolution of metallic Na with higher reversibility because of improved passivation and suppression of side reactions between Na metal and propylene carbonate solution containing Na salts. 相似文献
502.
Shinichi Komaba Wataru Murata Toru Ishikawa Naoaki Yabuuchi Tomoaki Ozeki Tetsuri Nakayama Atsushi Ogata Kazuma Gotoh Kazuya Fujiwara 《Advanced functional materials》2011,21(20):3859-3867
Recently, lithium‐ion batteries have been attracting more interest for use in automotive applications. Lithium resources are confirmed to be unevenly distributed in South America, and the cost of the lithium raw materials has roughly doubled from the first practical application in 1991 to the present and is increasing due to global demand for lithium‐ion accumulators. Since the electrochemical equivalent and standard potential of sodium are the most advantageous after lithium, sodium based energy storage is of great interest to realize lithium‐free high energy and high voltage batteries. However, to the best of our knowledge, there have been no successful reports on electrochemical sodium insertion materials for battery applications; the major challenge is the negative electrode and its passivation. In this study, we achieve high capacity and excellent reversibility sodium‐insertion performance of hard‐carbon and layered NaNi0.5Mn0.5O2 electrodes in propylene carbonate electrolyte solutions. The structural change and passivation for hard‐carbon are investigated to study the reversible sodium insertion. The 3‐volt secondary Na‐ion battery possessing environmental and cost friendliness, Na+‐shuttlecock hard‐carbon/NaNi0.5Mn0.5O2 cell, demonstrates steady cycling performance as next generation secondary batteries and an alternative to Li‐ion batteries. 相似文献
503.
Eiji Maruyama Shingo Okamoto Akira Terakawa Wataru Shinohara Makoto Tanaka Seiichi Kiyama 《Solar Energy Materials & Solar Cells》2002,74(1-4)
This paper reviews recent progress in large-area a-Si/a-SiGe tandem solar cells at Sanyo. Optimized hydrogen dilution conditions for high-rate deposition of hydrogenated amorphous silicon (a-Si:H) films and thinner i-layer structures have been systematically investigated for improving both the stabilized efficiency and the process throughput. As a result, a high photosensitivity of 106 for a-Si:H films has been maintained up to the deposition rate of 15 Å/s. Furthermore, the world's highest initial conversion efficiency of 11.2% which corresponds to a stabilized efficiency of about 10% has been achieved for a 8252 cm2 a-Si/a-SiGe tandem solar cell by combining the optimized hydrogen dilution and other successful technologies. 相似文献
504.
Application of an ecosystem model for aquatic ecological risk assessment of chemicals for a Japanese lake. 总被引:4,自引:0,他引:4
Wataru Naito Ken-ichi Miyamoto Junko Nakanishi Shigeki Masunaga Steven M Bartell 《Water research》2002,36(1):1-14
The Lake Suwa version of the comprehensive aquatic systems model (CASM-SUWA) was developed using field data from Lake Suwa and evaluated to examine the utility of CASM-SUWA for assessing the ecological risk of chemicals for aquatic ecosystems. The calibration of the parameters for the model provided that the established reference model simulation could reproduce complex seasonal biomass behavior of populations that were not significantly different from the general seasonal pattern for the Lake Suwa ecosystem. The sensitivity analyses revealed the potential importance of indirect effects and demonstrated that the parameter values of all the trophic levels were important in determining the biomass of each trophic level in the model. The risk estimation of linear alkylbenzene sulfonates (LAS) demonstrated that the model estimated the risks of direct toxic effects on each population and the indirect ecological effects that propagate through the food-web in the model ecosystem. The CASM-SUWA-derived benchmark levels were approximately one order of magnitude less than the field-derived NOECs in literature. The analyses of the comparison implied that the model could provide a good basis in determining an ecological protective level of a chemical of concern in aquatic ecosystem. This modeling study demonstrated that the model can be used to provide additional information for the decision-making process in the management of the aquatic ecological risk of chemicals. 相似文献
505.
We demonstrated an all-plastic waveguide organic dye laser with distributed feedback (DFB) resonator. We fabricated DFB structure on a surface of SU-8 2002 photoresist polymer using the interference of two beams of a frequency-tripled Nd:YAG pulse laser at 355 nm. The typical grating pitch of fabricated DFB structure was 190, 380 and 570 nm, corresponding to the number of mode m, and each corresponding grating amplitude was ca. 1, 4-5, and 25 nm, respectively. Shallow amplitude of 1 or 4-5 nm is ascribed to the wide incidence angle of the interference beams. Threshold of lasing for m = 3 is lower than that for m = 1 or m = 2 depending on the emission wavelength. DFB structure with the smaller amplitude of gratings at m = 1 and 2 is required for the higher threshold of laser emission. By controlling the grating pitch with nanometer scale, we can tune the wavelength of laser emission with 40 to 60 nm tunability. Effective energy transfer via nonradiative Förster transfer mechanism assists in lowering the threshold of laser emission. 相似文献
506.
Novel crystalline MoVO oxide was employed as the catalyst in the aerobic oxidation of alcohols to the corresponding carbonyl compounds. Reactions were mainly conducted at 353 K in pure oxygen or air (1 atm). The selectivities for benzaldehydes were more than 95% in all cases. The conversions of benzyl alcohols varied from 10% to 99% depending on the substituent. A Hammett plot gave a moderate ρ-value of −0.249 (r2 = 0.98), suggesting that the reaction processes may involve hydride abstraction. The oxidation of primary alkanols afforded aldehydes, and secondary alcohols were mainly dehydrated to olefins. It was found that the conversion of linear alkanols decreased with the length of alkanols. Kinetic analysis showed that catalytic reaction rate was first-order dependent on the concentrations of substrate and of catalyst. The apparent activation energy was estimated to be 45.7 kJ mol−1. Catalytic reactions took place on the 6- or 7-member rings on the a–b basal plane, where highly dense unsaturated metal cation centers and oxygen anion might serve as catalytic active sites. 相似文献
507.
Kobayashi S Kawai W Wakayama S 《Journal of materials science. Materials in medicine》2006,17(11):1089-1093
Hydroxyapatite (HA) is known to be biocompatible and osteoconductive, and can be synthesized chemically. The objective of
the present study is to clarify the effect of pressure during sintering on the mechanical properties of HA. HA was sintered
using a hot press system at a uniaxial pressure ranging from 7.81 to 62.5 MPa at a maximum temperature of 1200∘C with a heating rate of 10∘C/min. The density of the HA increased with increasing pressure and peaked at the sintering pressure of 31.2 MPa. Four-points
bending tests and fracture toughness measurements with indentation method were conducted to clarify the effect of sintering
pressure. Bending strength decreased at the pressure > 31.2 MPa. This result indicates that residual stress generated during
sintering process became larger with increasing pressure. Fracture toughness were also lower with high density HA. 相似文献
508.
This paper presents a performance improvement for trajectory tracking for fast‐response and high‐precision positioning using sequential adaptive compensation for disturbances. A mathematical disturbance model formulated and parametrized by an iterative learning process can estimate the actual disturbance, and the model can be sequentially adapted using the recursive least squares method so that it shows adaptivity to disturbance variations. The proposed positioning control approach involving disturbance modeling and compensation has been verified by experiments using a linear motor‐driven table system. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(4): 52–63, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22280 相似文献
509.
Wataru Kuriyama Yasunori Ino Osamu Ogata Noboru Sayo Takao Saito 《Advanced Synthesis \u0026amp; Catalysis》2010,352(1):92-96
A ruthenium complex was found to catalyze the hydrogen reduction of esters under mild and neutral conditions. A variety of optically active esters can be reduced to the corresponding alcohols in excellent yield without loss of their optical purity or causing undesirable side reactions. Hydrogen reduction needs such simple operations – reaction, concentration, and purification – that the violent quench step and extraction step, which accompany conventional sodium borohydride or lithium aluminum hydride reduction, can be omitted. 相似文献