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951.
Understanding the Origin of Li2MnO3 Activation in Li‐Rich Cathode Materials for Lithium‐Ion Batteries
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Delai Ye Guang Zeng Kazuhiro Nogita Kiyoshi Ozawa Marlies Hankel Debra J. Searles Lianzhou Wang 《Advanced functional materials》2015,25(48):7488-7496
Li‐rich layered cathode materials have been considered as a family of promising high‐energy density cathode materials for next generation lithium‐ion batteries (LIBs). However, although activation of the Li2MnO3 phase is known to play an essential role in providing superior capacity, the mechanism of activation of the Li2MnO3 phase in Li‐rich cathode materials is still not fully understood. In this work, an interesting Li‐rich cathode material Li1.87Mn0.94Ni0.19O3 is reported where the Li2MnO3 phase activation process can be effectively controlled due to the relatively low level of Ni doping. Such a unique feature offers the possibility of investigating the detailed activation mechanism by examining the intermediate states and phases of the Li2MnO3 during the controlled activation process. Combining powerful synchrotron in situ X‐ray diffraction analysis and observations using advanced scanning transmission electron microscopy equipped with a high angle annular dark field detector, it has been revealed that the subreaction of O2 generation may feature a much faster kinetics than the transition metal diffusion during the Li2MnO3 activation process, indicating that the latter plays a crucial role in determining the Li2MnO3 activation rate and leading to the unusual stepwise capacity increase over charging cycles. 相似文献
952.
Spring Andrew M. Maeda Daisuke Ozawa Masaaki Odoi Keisuke Qiu Feng Yamamoto Kazuhiro Yokoyama Shiyoshi 《Polymer Bulletin》2015,72(3):503-521
Polymer Bulletin - By the precise combination of both cyclohexyl- and octyl-substituted norbornene-dicarboximide monomers, a series of copolymers were prepared by ring-opening metathesis... 相似文献
953.
The data available for the thermodynamic properties of propane, \(n\) -butane, and isobutane at temperatures above 440 K are outdated and show significant discrepancies with each other. The ambiguity associated with these data could be limiting to the development of any understanding related to the effects of mixing of these substances with other materials such as \(\text{ CO}_{2}\) , ammonia, and non-flammable or lower-flammable HFC refrigerants. In this study, the (p, \(\rho \) , T) properties of propane, \(n\) -butane, and isobutane were measured at temperatures ranging from (360 to 600) K and pressures ranging from (50 to 200) MPa. Precise measurements were carried out using a metal-bellows variable volumometer with a thermostatted air bath. The expanded uncertainties \((k = 2)\) in the temperature, pressure, and density measurements were estimated to be \(<\) 5 mK, 0.02 MPa, and 0.88 kg \(\cdot \) m \(^{-3}\) ( \(T\le 423\) K, \(p<100\) MPa), 0.76 kg \(\cdot \) \(\text{ m}^{-3}\) ( \(T\le 423\) K, \(p\ge 100\) MPa), 0.76 kg \(\cdot \) \(\text{ m}^{-3}\) ( \(T>423\) K, \(p < 100\) MPa), and 2.94 kg \(\cdot \) \(\text{ m}^{-3}\) ( \(T>423\) K, \(p \ge 100\) MPa), respectively. The data obtained throughout this study were systematically compared with the calculated values derived from the available equations of state. These models agree well with the measured data at higher temperatures up to 600 K, demonstrating their suitability for an effective and precise examination of the mixing effects of potential alternative mixtures. 相似文献
954.
Kazuhiro Sakai Naoya Sumi Kenichiro Yamamoto 《Dynamical Systems: An International Journal》2014,29(4):569-577
In this paper, we consider the set of diffeomorphisms which are measure-expansive for any ergodic measure, and study the set from the viewpoint of geometric theory of dynamical systems. It is proved that (1) there exists a non-empty C1-open set of robustly non-hyperbolic and transitive diffeomorphisms such that each element of the set is measure-expansive for any ergodic measure, and that (2) C1-generically, a diffeomorphism is measure-expansive for any generic ergodic measure. 相似文献
955.
Direct Evidence for Structural Transition Promoting Shear Thinning in Cylindrical Colloid Assemblies
Kazuhiro Shikinaka Keisuke Kaneda Saori Mori Tei Maki Hiroyasu Masunaga Yoshihito Osada Kiyotaka Shigehara 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(9):1813-1820
In this paper, we describe stimuli‐responsive hydrogels prepared from a rigid rod‐like polyelectrolyte ‘imogolite’ and a dicarboxylic acid. The hydrogel exhibited thixotropy in response to mechanical shock within the order of seconds or sub‐seconds. Here, using the latest structural/rheological characterisation techniques, the relationship between the structural transition processes and the shear thinning was estimated. The evidence obtained by the experiments revealed for the first time the direct relationship between the microscopic structural change and the macroscopic thixotropic behavior that have been extensively discussed. The thixotropic hydrogel has the hierarchical architecture in the combination of imogolite and dicarboxylic acid, i.e., sheathed nanotubes/hydroclusters of cross‐bridged nanotubes/frameworks. The formation and disintegration of the network structure upon resting and agitating, respectively, were the origin of gel/sol transition (thixotropy), although the hydroclusters of cross‐bridged nanotubes were maintained throughout the transition. 相似文献
956.
Chunmeng Dou Tomoya Shoji Kazuhiro Nakajima Kuniyuki Kakushima Parhat Ahmet Yoshinori Kataoka Akira Nishiyama Nobuyuki Sugii Hitoshi Wakabayashi Kazuo Tsutsui Kenji Natori Hiroshi Iwai 《Microelectronics Reliability》2014
Adopting the gated p–i–n diode configuration, the interface state density (Dit) at the Si/SiO2 interface of Si fin structures on Silicon-on-Insulator (SOI) wafers has been systematically studied using charge pumping method. The optimal forming gas annealing temperature for the three-dimensional (3D) surface is extracted. A new methodology for separately quantifying the local Dit at different regions of the 3D surfaces (i.e., the top/side walls and the corners) is also derived by characterizing the fins with various widths and the planar counterparts. The results validate the necessity to independently consider the corner regions, at which substantially high local Dit situates, and thus further clarify the origin of high Dit at 3D surfaces. 相似文献
957.
Kazuhiro Miyauchi Yukihiko Yamashita Naoya Suzuki Nozomu Takano 《Journal of Electronic Materials》2014,43(9):3411-3422
The self-assembly of solder powder on pads is attractive as a novel interconnection method between chips and substrates. However, the solder used in this method is limited to Sn-58Bi and Sn-52In. In contrast, Sn-3Ag-0.5Cu has been relatively less studied despite its wide use as a lead-free solder in assembling semiconductor packages. Hence, here, polymeric materials incorporating Sn-3Ag-0.5Cu solder powder were investigated for the self-assembly of the solder on pads at temperatures up to 260°C in a lead-free reflow process. The self-assembly of the solder was observed with an optical microscope through transparent glass chips placed on substrates covered with the polymeric materials incorporating the solder powder. Differential scanning calorimetry measurements were performed to confirm the behaviors of the reaction of the resins and the melting of the solder. When epoxy resin with a fluxing additive was used as a matrix, self-assembly of the solder was prevented by the cross-linking reaction. Conversely, when thermoplastic resin containing carboxyl groups was used as a matrix, the self-assembly of solder was successfully achieved in the absence of fluxing additives. The shear strength of interconnection using reflowfilm with lamination was sufficient and significantly increased during the reflow process. However, the shear strength of the reflowfilm showed cohesive failure, possibly because of the brittle intermetallic compounds (Ag3Sn, Au4Sn) network in bulk was lower than that of conventional solder paste that showed interfacial failure after the reflow process with a rapid cooling rate. 相似文献
958.
Kazuhiro Ito Keiji Hamasaka Kazuyuki Kohama Yasuharu Shirai Masanori Murakami 《Journal of Electronic Materials》2014,43(7):2540-2547
Cu(0.5 at.%Mg) alloy films were deposited on glass substrates, and annealed at 200–400 °C in vacuum. The resistivity of the Cu(Mg) films was reduced to about 3.0 μΩcm after annealing at 200 °C for 30 min, and the tensile strength of adhesion of the Cu(Mg) films to the glass substrates was increased to 30–40 and 35–55 MPa after annealing at 250 and 300 °C, respectively. The reduction in resistivity can be explained as reduced impurity scattering and grain-boundary scattering, since Mg segregation to the film surface and Cu(Mg)/glass interface, and consequent Cu grain growth, were observed. Increased adhesion of the Cu(Mg) films to glass substrates after annealing was also explained by the strong segregation of Mg atoms, and the formation of a reaction layer at the interface. Mg atoms were observed to have reacted with the glass substrates and formed a thin crystalline MgO layer at the interface in the samples annealed at 300 °C, while Mg atoms were highly concentrated above the Cu(Mg)/glass interface without oxide formation at the interface in the samples annealed at 250 °C. Thus, the process temperature and time to obtain low-resistivity and high-adhesion Cu alloy films on glass substrates could be reduced to 250 °C and 30 min using Cu(Mg) films. 相似文献
959.
Shohei Kumagai Kazuhiro Hotta 《IEEJ Transactions on Electrical and Electronic Engineering》2015,10(2):181-185
Detecting particles in intracellular images and estimating their radii is important for investigating the causes of clinical conditions. Presently, particles are manually counted by observers, which is time consuming and subjective. Thus, we propose an automatic particle counting and radius estimation method based on pattern recognition techniques. Particles are analyzed by a computer in two processes. During the first process, particles are detected using face recognition via a support vector machine. In the second process, the edge points of a detected particle are distinguished by the intensity difference between the particle and the background. The edge points are extracted and fitted by a circle by a voting technique. The proposed method accurately located 96.04% of the particles detected by manual counting. ImageJ, the particle detection software generally used in cell biology, detected 72.32% of the particles. Therefore, our method yields higher accuracy than ImageJ. Moreover, the effectiveness of radius estimation was also experimentally verified. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
960.
Takeyasu Saito Yukihiro Shimogaki Katsuro Sugawara Shinji Nagata Hiroshi Komiyama 《Microelectronic Engineering》2006,83(10):1994-2000
This paper describes reaction kinetics of chemical vapor deposition of WSix films from WF6 and SiH2Cl2, focusing on the effect of added H2, SiH4, and Si2H6 as an active reaction initiator. Our studies indicate that the temperature at which film formation is extinguished, Tex, can be lowered by introducing H2 instead of the standard Ar carrier gas. For a SiH2Cl2/WF6 pressure ratio of 20, H2 addition changed the deposition mode from selective W deposition to blanket WSix deposition. The added H2 also improved the step-coverage profile for substrate temperatures below 600 °C. Measured step coverage profiles indicate that the activation energy of deposition species was 147 kJ/mol. Adding either SiH4 or Si2H6 can assist the film-forming reactions to achieve acceptable Si/W atomic composition ratios. Under these conditions, the residual fluorine concentration remained at acceptably low levels that are typical of conventional WF6/SiH2Cl2 CVD processes. 相似文献