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Electrochemical quartz crystal microbalance (EQCM) measurements were carried out during electrochemical deposition/dissolution of Li on the Ti and Pt substrate electrodes of AT-cut quartz crystals in a 1 M LiPF 6 in propylene carbonate (PC) and dimethoxyethane (DME) (1:1 in volume) and a 1 M LiPF 6 in ethylene carbonate (EC) and DME (1:1 in volume). The mass change during Li deposition on the Pt substrate was about half that on the Ti substrate because the alloy formation of Li–Pt suppressed passivation reactions of deposited Li. Furthermore, it was also suggested that the amount of organic compounds in passivation films formed in the PC-based electrolyte was larger than that in the EC-based electrolyte due to PC reacting more easily with Li than EC. The EQCM measurement of the passivation film formations during alloying Li with Pb electrodeposited on the Ti substrate was also conducted successfully. The Li–Pb alloy formation occurred under 0.5 V, in which the potential profile was divided into two regions associated with the phase diagram of Li–Pb alloy. The mass change due to passivation film formations increased in accordance with the changes of Li–Pb alloy compositions into Li rich phases, which were thought either to enhance the reactiveness of Li or decrease the diffusiveness of Li in Li–Pb alloy.

We calculated intravalley and intervalley phonon scattering rates of accelerated electrons under intense midinfrared laser fields. We extended the Keldysh theory, which assumes oscillatory motion of Bloch electrons driven by intense laser fields, to phonon scattering of electrons in semiconductors. We find that phonon emission is possible even if the initial electron energy is less than the phonon energy due to multi-photon absorption processes. We also find that the scattering rates increase with electric field strength and wavelength. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We have measured optical transmittance through germanium in the mid-infrared region at room temperature using the Osaka free-electron laser (FEL). In spite of the fact that germanium is transparent in the mid-infrared region, we observed strong suppression of optical transmission under high-intensity FEL excitation. We found that the observed suppression is due to optical absorption in germanium. To analyze the experimental results, we have calculated optical transmittance of germanium within Keldysh theory

Since 1992 the Lithium Battery Energy Storage Technology Research Association (LIBES) has been conducting a 10-year research and development project, ‘Development of the Dispersed-type Battery Energy Storage Technology’, on two types of batteries, an electric vehicle (EV) application type and a stationary type for a home-use energy storage system for load leveling. After the first interim evaluation in 1995, the work load of the battery developers in LIBES was divided into the following two groups: one is the group for the development of large-scale cells and battery modules with four approaches; and the other is the group for the development of next-generation battery technologies including lithium polymer battery technology. The aim of the research and development of lithium polymer battery technology in LIBES is to develop the solid-state lithium polymer battery using carbon material as the anode. Our laboratory has developed and improved a random copolymer of ethylene oxide and propylene oxide (SPE(B)) as one of the candidate polymer electrolytes.

The Lithium Battery Energy Storage Technology Research Association (LIBES) has been conducting R&D on large-scale lithium secondary batteries for use in electric vehicles and home-use load leveling systems as part of the New Sunshine Program by the Agency of Industrial Science and Technology (AIST) of the Ministry of International Trade and Industry (MITI) under a contract with the New Energy and Industrial Technology Development Organization (NEDO) since FY 1992. The R&D by LIBES, which is in Phase 2, has developed several hundred Wh class prototype cells of 4 types and 2 or 3 kWh class modules of each type connecting those cells in series. At the same time, LIBES member companies are conducting studies on supporting technologies for the above R&D, on the evaluation test, and on next-generation lithium secondary battery technology development. Here we describe the current results and status of LIBES's R&D as well as those technological aspects.

Functional mapping was carried out to address the amino acid residues responsible for the activity of the antibacterial peptide apidaecin from the honeybee by an in vivo assay system developed previously. The C-terminal region and many of the proline and arginine residues which are present at high frequency in apidaecin were found to play an important role in its antibacterial activity.

Cyclotron resonance measurements have been carried out to evaluate the effective mass of electrons in short-period (GaAs)n/(AlAs)n superlattices (SLs). In order to clarify the Γ-X crossover occurring at n ≈ 12 due to the zone folding effect, we have measured effective masses in SLs with n ranging from 8 to 16 using cyclotron resonance in high magnetic fields (up to 150 T). We found a clear cyclotron resonance in the transmission of 10.61 μm radiation at 99 T in type I SLs (corresponding to an effective mass of 0.098m0 and broad cyclotron resonances at around 90 T in type II SLs in the transmission of 23 μm radiation, which give an effective mass of 0.21 ± 0.01m 0. These resonances were found to be nearly independent of the number of monolayers n.

We have investigated electron transport in side-gated single quantum wires. The wires were produced by deep etching in GaAs/AlGaAs single and quantum well heterostructures. With increasingly negative gate voltage we observed a clear transition from a two-dimensional electron gas (2DEG) to a quasi-one-dimensional electron gas (1DEG). For the first time, enhanced mobility transport is detected in the GaAs/AlGaAs quantum well wire structure whereas a mobility loss occurs in the GaAs/AlGaAs single-heterostructure wire. The controversial behaviour is attributed to electron-density-related screening effects as well as gate-voltage-induced changes of the confinement potential in the growth direction favouring the quantum well wire structure in terms of high-electron-mobility 1DEG transport.

We determined the complete amino acid sequence of a novel subtilisin inhibitor, SIL15, which had been isolated from the culture supernatant of Streptomyces bikiniensis and shown to be a member of the Streptomyces subtilisin inhibitor (SSI)-like (SIL) protein family, and then identified its reactive site. SIL15 is composed of 113 amino acids and exists as a dimer. Compared with other SSI-family inhibitors, SIL15 was found to be unique in that it possesses a Gln residue at the P1 site of the reactive site and has two-residue insertions in two regions, one in the alpha 1-helix and the other in the flexible loop region near the reactive site. Inhibition of subtilisin BPN' by SIL15 (inhibitor constant, 2.7 x 10(-11) M) was due to the presence of a Gln residue at the P1 site, which was well consistent with the results obtained for P1-site mutants of SSI and turkey ovomucoid domain 3.

A unique antibacterial peptide derivative found in immune honeybee lymph, apidaecin 1b (AP1), was randomly mutagenized and characterized by a newly established system to analyze in vivo its structure-function relationship. Initially, a high-level expression host-vector system for AP1 in Escherichia coli was constructed by creating a fusion protein with the highly stable Streptomyces subtilisin inhibitor (SSI) molecule. Expression of the SSI-AP1 fusion protein was found to depend on the concentration of the transcriptional inducer isopropyl-beta-D-thio-galactopyranoside (IPTG) and to parallel the degree of growth inhibition of the transformant cells. Subsequently, apidaecin derivatives produced by localized random mutagenesis were screened with this IPTG concentration-controlled in vivo system by monitoring the growth inhibition patterns of the transformant cells. One mutant apidaecin (P9L) that had reduced activity was purified and isolated from the periplasmic fraction of an E. coli transformant. Its antibacterial activity was reduced to one-third of that of wild-type apidaecin. When considered together with the other mutations, it was concluded that several Pro residues, including that at the ninth position, are responsible for expression of the antibacterial action of apidaecin.

We have investigated the magnetotransport properties of quantum wires which were fabricated on high-mobility GaAs/GaAlAs modulation-doped heterostructures by laser holography. For high temperatures (~ 150 K), magnetoresistance structures are revealed, which are due to the occurrence of magnetophonon resonances in the wire. This effect is used to determine the polaron mass which is found to be about 10% larger than to the polaron mass in bulk GaAs. In addition, hydrostatic pressure is used to modify the electron density in these quantum wires. We observe an increase of the 1D subband energy spacing with a decreasing electron density and an enhancement of the magnetophonon resonance amplitudes.

By analysing exciton binding energies, we have experimentally investigated static dielectric constant of GaInNAs. Contrary to conventional semiconductors, it was found that both static dielectric constant and bandgap decrease by adding nitrogen.

Sites for Cys substitutions to form a disulfide bond were chosen in subtilisin E from Bacillus subtilis, a cysteine-free bacterial serine protease, based on the structure of aqualysin I of Thermus aquaticus YT-1 (a thermophilic subtilisin-type protease containing two disulfide bonds). Cys residues were introduced at positions 61 (wild-type, Gly) and 98 (Ser) in subtilisin E by site-directed mutagenesis. The Cys-61/Cys-98 mutant subtilisin appeared to form a disulfide bond spontaneously in the expression system used and showed a catalytic efficiency equivalent to that of the wild-type enzyme for hydrolysis of a synthetic peptide substrate. The thermodynamic characteristics of these enzymes were examined in terms of enzyme autolysis (t1/2) and thermal stability (Tm). The half-life of the Cys-61/Cys-98 mutant was found to be 2-3 times longer than that of the wild-type enzyme. Similar results were obtained by differential scanning calorimetry. The disulfide mutant showed a Tm of 63.0 degrees C, which was 4.5 degrees C higher than that observed for the wild-type enzyme. Under reducing conditions, however, the characteristics of the mutant enzyme were found to revert to those of the wild-type enzyme. These results strongly suggest that the introduction of a disulfide bond by site-directed mutagenesis enhanced the thermostability of subtilisin E without changing the catalytic efficiency of the enzyme.

We have investigated the temperature dependence of midinfrared optical absorption in germanium under intense free-electron laser fields. We observed that the absorption decreases as temperature decreases. We find that the temperature dependence of the absorption is consistent with calculations based on the Keldysh theory, in which the temperature dependence of the direct-gap energy of germanium is considered.

We have investigated the effects of high-power laser pulses on a transparent material using a free-electron laser (FEL). We have measured optical transmittance through a germanium crystal in the midinfrared region, $\ensuremath{\lambda}=5.3--12.4\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m}$ at room temperature. In spite of the fact that germanium is transparent in the midinfrared region, we have observed strong suppression of optical transmission under high-intensity FEL excitation.

Different degradation modes were observed under high and low reverse stress current conditions. The temperature dependence of the gradation was studied, and it was found that the degradation is greatest around 50 degrees C. The mechanisms of the degradation and its recovery were also investigated, using MOS structures and simulation. MOSFET evaluation indicated that electron trapping and interface state generation occur during the stress. Simulation confirmed that the degradation is caused mainly by the interface states generated in the oxide near the emitter-base junction. >

Three samples with different thicknesses of polysilicon-silicon interfacial oxide were prepared. The influence of the interfacial oxide on the electrical characteristics of 0.8- mu m BiCMOS VLSIs was studied. From the results, the maximum interfacial oxide thickness allowed for BiCMOS LSIs was determined. To control the interfacial oxide thickness, the ball-up mechanism was studied using HRXTEM combined with energy-dispersive X-ray spectroscopy measurements. The optimum heat treatment after emitter deposition to realize 0.5- mu m BiCMOS VLSI was also determined. >

The current gain of a bipolar transistor, h/sub FE/, is degraded by the emitter-base reverse-bias stress. The mechanism has been interpreted to be due to an increase in the interface state density, while its dependence on stress time has been found to be proportional to t/sup n/, where n is 0.5 to 1. It was expected that if the stress time was long enough, the increase in interface state density would saturate to a maximum value. However, an anomalous time dependence of base current increase-a slower increase initially followed by a rapid increase in the intermediate stage-was found for bipolar transistors whose junction surface was oxidized in dry ambient conditions. This is explained by the hypothesis that the potential distribution is modulated by the charge in the oxide or at the interface. >

Magnetophonon resonances are studied in quantum wires with square confinement potential. Magnetoconductivity calculated by using the Kubo formula is found to have two components; one related to the current carried by electron hopping motion between the localized cyclotron orbits through electron-phonon interaction, and the other caused by the current carried by electron motion affected by the confinement potential. The latter, σ po, is found to be two orders of magnitude greater than the former, σ ep, around the fundamental resonance condition in the case of a GaAs quantum wire whose width is 200A and barrier height is 100meV.

Dilute nitrides are novel III–V semiconductors that have been developed for photonic and electronic devices. Although they have been investigated, some of their characteristics have not been established yet. In this study, the static dielectric constant of dilute nitrides was experimentally estimated from the exciton binding energy. The results imply that nitrogen incorporation in III–V semiconductors decreases both the static dielectric constant and bandgap. This behavior is opposite to that of conventional semiconductors.

A method of high-performance and simple fully complementary bipolar MOS (FCBiMOS) process integration is proposed that is compatible with a conventional 0.5-mm CMOS and BiCMOS process. This process is based on two key technologies. One is a high-dose boron MeV ion implantation combined with an epitaxial wafer. The other is rapid thermal processing (RTP) for high current gain. It has been confirmed that use of a oxygen-free epitaxial wafer solves the problem of MeV ion implantation for a device application with the residual secondary defects. As a result, a pnp transistor with a cut-off frequency of 5 GHz and a current gain of 85 was achieved without any tradeoff of other device characteristics

The ability to degrade [14C]-naphthalene was transferred from Bacillus megaterium to B. subtilis by extracting B. megaterium DNA and introducing it into B. subtilis using the protoplast-polyethylene glycol method. Naphthalene degradation was indicated by the accumulation of water soluble 14C activity and the presence of a unique solvent-extractable metabolite on TLC analysis. In addition, resistance to dibenzofuran, p-chlorobiphenyl, and naphthalene (as demonstrated by lack of growth inhibition by these compounds) was transferred by the same technique. B. megaterium ATCC 13368 and derivatives conditioned to the presence of each of these three chemicals were used as DNA donors. B. subtilis transformants showed greater resistance to the chemical to which the DNA donor B. megaterium had been conditioned.

The mixed micellar behavior of sodium cholate, NaC, and octa-oxyethylene glycol n-decyl ether, C10E8, has been studied from the viewpoints of the aggregation number and the polarity of the interior of the micelle. The polarity of the interior of the mixed micelle obtained from I 1 I 3 and the lifetime of pyrene fluorescence shows that the solubilization site of pyrene varies with the molar fraction. This fact is considered to be caused by the differences in the chemical structure and the hydrophobic nature between NaC and C10E8. Concentration dependencies are seen for the aggregation number and I 1 I 3 . These dependencies indicate that the size and composition in the mixed micelles vary with the total concentration of surfactants, and that the initial micelles formed near the CMC contain higher molar fractions of C10E8 than do analytical molar fractions. Furthermore, theoretical calculations using regular solution theory and excess thermodynamic quantities have been performed with the values of CMCs. The calculated values of the molar fraction in the micelle were lower than those of the analytical molar fraction; however, there was a large difference between the values of the two methods. The experimental results agreed best with ones obtained from the excess thermodynamic quantities.

Three yeast strains, which gave over 93% sugar conversion efficiency (SCE) in sweet sorghum juice containing 20% total sugar in a previous study, were submitted to 3 and 6% ethylmethanesulfonate (EMS) to induce mutations. Several mutants produced by the EMS treatment and their respective wild types grew well in media containing up to 40% sugar. Some mutants tolerated 2·5% more alcohol than their respective wild types. Saccharomyces cerevisiae IZ 1716 Mutant 10 produced a significantly greater yield of ethanol from sweet sorghum juice containing 26% sugar than the wild type. Under large-scale fermentation, this mutant had an SCE of 89·4% after 36h in sweet sorghum juice containing 28% sugar. The final alcohol concentration reached 13·28% (w/v) after 48h, corresponding to an SCE of 93·57%.