Li nuclear magnetic resonance studies of hard carbon and graphite/hard carbon hybrid anode for Li ion battery

The hard carbon is attractive for the Li ion battery because of its higher capacity than the theoretical value of 372 Ah kg⁻¹ based on the composition of stage 1 Li-intercalated graphite, LiC₆. However, since the Li-doping reaction occurs at the potential of around 0 V versus Li/Li⁺ reference electrode, it is often pointed out the possibility of Li metal deposition on the surface of anode. From the viewpoint of the safety, it may be a moot point. In the present study, ⁷Li NMR measurement was performed to estimate the degree of Li metal deposition on the surface of graphite and hard carbon anode. As a result, it is clarified that the Li metal deposition does not occur up to 110% over-discharge of the reversible capacity of hard carbon, whereas in the case of graphite anode, Li metal deposition occurred above 105% over-discharge of the capacity. From the ⁷Li NMR spectroscopy, the safety limit of hard carbon is rather superior to that of graphite.     

Lossless broad-band monolithic microwave active inductors

Lossless broadband microwave active inductors for general-purpose use in microwave circuits are proposed, and their characteristics are discussed. These active inductors are composed of a common-source cascode FET and a feedback FET, and operate in a wide frequency range with very low series resistance. Their low-loss characteristics are demonstrated by simulation and experimental results. A maximum Q factor of 65 is obtained. Theoretically, it can reach infinity. The inductance value can be controlled by an external voltage control     

Divider and combiner line-unified FET's as basic circuit functionmodules. I

The purpose is to realize miniaturized and broadband function blocks with very simple configurations for multifunction monolithic microwave circuits. FET-sized combiners and dividers, in phase and out of phase, based on a novel line-unified-FET (LUFET) concept are described and demonstrated. Some effective extensions such as extended combiner LUFETs, magic T LUFETs, and phase inverter LUFETs are also described. The extension of the basic combiner and divider LUFETs allows the realization of various circuit functions in a very small area. The area of fabricated LUFETs is between 0.1 and 0.3 mm², and the operating frequency bandwidth approaches 20 GHz. The LUFET mitigates the size and complexity problems considerably and expands the application of combiners and dividers to various multifunction microwave monolithic integrated circuits (MMICs)     

Fabrication of 0.95Sn−0.05Au solder micro-bumps for flip-chip bonding

This letter describes the successful fabrication of a 0.95Sn−0.05Au solder microbump on a compound semiconductor wafer by reflowing of multi-layer metal film. Since the inherent interdiffusion in Au−Sn phases results in the alloying of multi-layer films, the composition of micro-bump is well controlled by the thickness of constituent metal films. The micro-bumps melt at about 220 C, which is close to the lowest eutectic temperature in a Au−Sn system. Solder bonding using 0.95Sn−0.05Au micro-bump is a very useful technique for the flipchip bonding of compound semiconductor devices.     

Mmic technology for communication systems

MMIC technology is recently progressing at a rapid rate and is now being applied in communications systems. However, there remain few practical applications. This is mainly due to the high cost of conventional mmics because of the small market size and specialized needs. This paper introduces three new technical approaches that overcome the problems: uniplanar mmic, line unified fet^lufet), and multilayer mmic. Concepts and several examples of these technologies are described. It is shown that these technologies are effective not only for cost reduction but also for increased performance. In addition, one example of system application is described.     

Evidence of multiple ethanol pools in the brain: an in vivo proton magnetization transfer study

Studies of isolated cell membranes and animal brain extracts have shown that ethanol (EtOH) partitions into cell membranes. We tested the hypothesis that EtOH in the living brain after EtOH administration exists in two or more pools: a free, mobile pool of EtOH and one or more EtOH pools that are restricted in their molecular mobility, possibly because of association with membranes. In vivo brain proton magnetic resonance spectroscopy (1H MRS) routinely detects the methyl protons of the mobile EtOH pool but does not detect motionally restricted EtOH. We used in vivo brain 1H MRS in rat brain (n = 11) after intraperitoneal EtOH administration to measure the signal intensity of methyl EtOH protons in the presence and absence of off-resonance saturation. Off-resonance saturation resulted in a 33 +/- 4% decrease of the EtOH methyl proton signal. We interpret this signal reduction as a magnetization transfer effect. It is consistent with the existence of an MRS-invisible EtOH pool with restricted molecular mobility, which is in exchange with the free EtOH pool. Off-resonance saturation at the water frequency resulted in an even larger decrease of the EtOH methyl signal, consistent with water molecules being in close proximity to EtOH molecules at the restricted motion site(s). These results provide support for the hypothesis that partial MRS-invisibility of brain EtOH is at least to some extent caused by the presence of a (MRS-invisible) pool of motionally restricted EtOH. They also strongly suggest that water suppression, routinely used in in vivo 1H MRS, may reduce the observable EtOH methyl signal intensity through a magnetization transfer mechanism. These studies may provide both a mechanism of, and a means to investigate the alterations of EtOH MRS visibility observed in heavy drinkers.     

Calcium promotes cell survival through CaM-K kinase activation of the protein-kinase-B pathway

The protection against apoptosis provided by growth factors in several cell lines is due to stimulation of the phosphatidylinositol-3-OH kinase (PI(3)K) pathway, which results in activation of protein kinase B (PKB; also known as c-Akt and Rac) and phosphorylation and sequestration to protein 14-3-3 of the proapoptotic Bcl-2-family member BAD. A modest increase in intracellular Ca2+ concentration also promotes survival of some cultured neurons through a pathway that requires calmodulin but is independent of PI(3)K and the MAP kinases. Here we report that Ca2+/calmodulin-dependent protein kinase kinase (CaM-KK) activates PKB directly, resulting in phosphorylation of BAD on serine residue 136 and the interaction of BAD with protein 14-3-3. Serum withdrawal induced a three- to fourfold increase in cell death of NG108 neuroblastoma cells, and this apoptosis was largely blocked by increasing the intracellular Ca2+ concentration with NMDA (N-methyl-D-aspartate) or KCl or by transfection with constitutively active CaM-KK. The effect of NMDA on cell survival was blocked by transfection with dominant-negative forms of CaM-KK or PKB. These results identify a Ca2+-triggered signalling cascade in which CaM-KK activates PKB, which in turn phosphorylates BAD and protects cells from apoptosis.     

A 630-mS/mm GaAs MESFET with Au/WSiN refractory metal gate

GaAs MESFET's with a gate length as low as 0.2 μm have been successfully fabricated with Au/WSiN refractory metal gate n⁺-self-aligned ion-implantation technology. A very thin channel layer with high carrier concentration was realized with 10-keV ion implantation of Si and rapid thermal annealing. Low-energy implantation of the n⁺-contact regions was examined to reduce substrate leakage current. The 0.2-μm gate-length devices exhibited a maximum transconductance of 630 mS/mm and an intrinsic transconductance of 920 mS/mm at a threshold voltage of -0.14 V     

Improvement in learning efficiency of multilayered neural networks based on dynamic systems

This paper proposes a new method which uses the dynamic systems for improving learning efficiency in multilayered neural networks. The shape of the error function is analyzed using Monte Carlo simulation, and the learning efficiency is improved on the basis of the shape analysis and the adaptive learning rate. The proposed method uses the adaptive learning rate which is determined from the gradient of the error function. The proposed method is applied to XOR and 5-bit parity check problems and the effectiveness and feasibility of the proposed method are verified. © 1999 Scripta Technica, Electr Eng Jpn, 129(4): 77–86, 1999     

Mechanical properties and morphological changes of poly(lactic acid)/polycarbonate/poly(butylene adipate‐co‐terephthalate) blend through reactive processing

The mechanical properties and morphological changes of poly(lactic acid) (PLA), polycarbonate (PC), and poly(butylene adipate‐co‐terephthalate) (PBAT) polymer blends were investigated. Several types of blend samples were prepared by reactive processing (RP) with a twin‐screw extruder using dicumyl peroxide (DCP) as a radical initiator. Dynamic mechanical analyses (DMA) of binary polymer blends of PC/PBAT indicated that each component was miscible over a wide range of PC/PBAT mixing ratios. DMA of PLA/PBAT/PC ternary blends revealed that PBAT is miscible with PC even in the case of ternary blend system and the miscibility of PLA and PBAT can also be modified through RP. As a result, the tensile strain and impact strength of the ternary blends was increased considerably through RP, especially for PLA/PBAT/PC = 42/18/40 (wt/wt/wt) with DCP (0.3 phr). Scanning electron microscopy (SEM) analysis of the PLA/PBAT/PC blends revealed many small spherical island phases with a domain size of approximately 0.05–1 μm for RP, whereas it was approximately 10 μm without RP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011