Effect of Metallic Oxides Containing Composite Electrodes on Crystallization and Ferroelectric Properties of Pb(Zr0.52,Ti0.48)O3 Thin Films Deposited by the Sol-Gel Method

In order to suppress polarization fatigue and decrease the leakage current of the PZT capacitor, composite electrodes consisting of MO₂ (RuO_x or IrO_x) as an effective diffusion barrier and considerably large amounts of Pt were deposited by magnetron co-sputtering to yield heterostructured PZT capacitors, Pt/(Pt+MO₂)//PZT(52/48)//(Pt+MO₂)/(Pt+M)/M/Pt/Ti(Ta)/SiO₂/Si(1 0 0), and the crystallinity and the orientation, the morphology of the surface and the cross section, and the composition depth profile of the PZT capacitor were examined by XRD analysis, SEM and AES, respectively, and the ferroelectric properties were measured. The results indicated that by adjusting the distribution and composition of the RuO₂ phase, the polarization loss of the PZT capacitor can be suppressed to as small as 5% after polarization reversals of 10⁹ while maintaining the effective polarization dP_r = P_r* – P_r ^{^} at 15 C/cm². The suppression of the polarization fatigue was found more effective with (Pt+IrO₂) electroding than (Pt+RuO₂) electroding. The leakage current of the PZT capacitor electroded with (Pt+MO₂) was a little larger than that of the PZT capacitor with Pt electrode. The possible reason was suggested.     

Measurement of atomic capture probabilities of negative pions in metal hydrides

Atomic capture probabilities of negative pions in some metal hydrides were measured. The capture by a hydrogen atom was detected by means of a pair of the annihilation rays of ⁰ which had been produced by the charge-exchange reaction of ^– with the capturing hydrogen nucleus (proton). This method ensures a high sensitivity and reliability of the measurements. The probabilities obtained were in agreement with previous measurements except for palladium hydride, which showed a much smaller probability than that given in the literature. The atomic capture of ^– is well described in the framework of the large mesic molecular model, in which the proportionality constant reflects the chemical states of the capturing atoms and also the neighboring ones.     

Next-to-leading-logarithmic parton shower in deep-inelastic scattering

We develop a next-to-leading-logarithmic parton shower in deep-inelastic scattering. The new model includes all kinds of next-to-leading-logarithmic corrections in the nonsinglet sector. It gives a definite scheme for QCD scale parameter Λ. Also it is possible to analyze final distributions of hadrons for obtaining \(\Lambda _{\overline {{\rm M}S} } \) . In order to include the corrections, we extend the jet calculus to the space-like case. Then we calculate three-body functions for the spacelike decay. In addition to extensive analyses of the scale breaking of the structure function, we study the three-jet fractions using the cluster algorithm and the energy flow distributions.     

Synthesis of star polymer by atom transfer radical polymerization with resorcinol‐core multifunctional initiator: The construction of nanocapsule via hydrolysis and olefin metathesis reaction of the obtained star polymer

Olefin group‐carrying styrene, 1‐but‐3‐enyl‐4‐vinylbenznene (BVB), was polymerized via atom transfer radical polymerization (ATRP) initiated from C‐methylcalix [4]resorcinarene‐based multifunctional initiator (CRA‐bib) at low conversion to produce star polymer [poly(BVB)] with narrow molecular weight distribution (M_w/M_n < 1.35). The copolymerization of styrene (St) with poly(BVB) (M_n = 11,000, M_w/M_n = 1.23) as a macroinitiator afforded star block copolymer [poly(BVB‐b‐St)] with M_n = 35,000 and M_w/M_n = 1.44. The BVB layer of poly(BVB‐b‐St), located between the St shell and the CRA core, was crosslinked by olefin metathesis reaction of olefin groups o the BVB moieties. The removal of the CRA core of the crosslinked poly(BVB‐b‐St) by hydrolysis using KOH as a base gave polymeric hollow sphere [poly(cored crossBVB‐b‐St)] with good solubility in organic solvents. The morphological structure of the poly(cored crossBVB‐b‐St) showed spherical aggregates in THF by scanning electron microscopy (SEM). Furthermore, the nanocapsule structure of poly(cored crossBVB‐b‐St) with hollow spheres was found to be observed by transmission electron microscopy (TEM). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4879–4888, 2008     

Recent results and future prospects of laser fusion research at ILE, Osaka

Reviewed are the present status of the fast ignition researches. Since 1997, the fast ignition experiment and theory researches have been extensively continued at the Institute of Laser Engineering of Osaka University. In particular, the cone-shell target experiments and simulation research have been progressing. In order to demonstrate heating of imploded high density plasma to the ignition temperature, in the April of 2003, the construction of heating laser of 10 kJ/10 ps/1.06 μm (Laser for Fusion Experiment; LFEX), for FIREX-I (Fast Ignition Realization Experiment) has started. The fabrication of DT foam cryogenic cone target is also under development as a collaboration program between Osaka University and NIFS (National Institute for Fusion Science). The LFEX will be completed in 2008. After the completion of LFEX, the foam cryogenic cone shell target experiment will start in 2008. As a new approach toward a compact ignition, an impact fusion has been proposed, where the ablative acceleration to the order of 10⁸ cm/s is the key issue. The ablation acceleration related to the impact fusion has been explored by experiments.     

Facile syntheses of homothia‐ and homoazacalixarenes

Decahomotetrathiacalix[6]arenes were conveniently prepared from the 2:2 cyclization reactions of bis(chloromethyl)phenol‐formaldehyde trimers with 1,2‐ethanedithiol in high yields. In contrast, the simi lar reactions of the trimers with 1,3‐propanedithiol instead of 1,2‐ethanedithiol gave 1:1 macrocycles, hexahomodithiacalix[3]arenes, in good yields. Homoazacalixarenes were also prepared from the analogous reactions using piperazines. These macrocycles adopt a cone‐like form as a preferable conformation in solution.     

Ab Initio study of isomerization reaction from c-OSiH2O to t-OSiHOH

The isomerization reaction from c-OSiH₂O to t-OSiHOH, a vital reaction to understand the spontaneous ignition of silane, has been reinvestigated with Gaussian-2 theory and the CASSCF(6,6) method. It has been found that the reaction proceeds through two consecutive steps; i.e., c-OSiH₂O undergoes isomerization to yield w-OSiH₂O, and then the latter is converted to t-OSiHOH. The G-2 energy of the transition state of the latter process is 4.3 kcal/mol higher than that of the former. However, the G-2 energy of this higher transition state plus H atom is still 4.8 kcal/mol lower than that of the original reactants of SiH₃ + O₂.