Superplasticity provides the possibility of high-temperature deformation processing of dense ceramics and has the advantages of greater shape form ability with better dimensional accuracy. Tensile ductility in fine-grained ceramics has been widely studied since large elongation was reported for finegrained yttria-doped tetragonal zirconia (Y-TZ). CuO- or Si0₂-doping effectively improves the ductility of Y-TZ, such that the maximum elongation exceeds 1000% for 5 wt% SiO₂ doped Y-TZ. However, the tensile ductility of Al₂O₃3-based ceramics is limited to 140%. Low ductility in fine-grained alumina has been attributed to rapid dynamic grain growth accompanied by large strain hardening and heavy intergranular cavitation. The addition of MgO or ZrO₂ is known to be effective in suppressing dynamic grain growth by solute drag (MgO) or second phase pinning (ZrO₂), but the resultant tensile ductilities are still very small as compared with that obtained in TZ. The cavitation incurred during high temperatured eformatioisn e xamineidn a MgO-dopeadlu minaa, Z rO₂-dispersaeldu minaan dY -TZA. q uantitative analysis of the cavity densities and cavity growth rates reveals that the damage accumulation in both the MgO-doped and ZrO₂-dispersed alumina is controlled strongly by a cavity nucleation process, whereas the damage in Y-TZ is controlled by cavity growth.

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In order to make clear the possibility of the keto-enol tautomerization and its mechanism in the 2pyridone acetic acid system in the ground state, the density-functional theoretical calculations at the B3LYP/6-31G (d) and B3LYP/6-31G (d, p) levels with a geometry-optimization were carried out for the 2-pyridoneformic acid system used as a model system. And the IR spectrum of 2-pyridoneacetic acid system was measured to ascertain the 2-pyridoneacetic acid complex (abbrev.: keto complex), the 2-hydroxypyridine (2-pyridinol) acetic acid complex (abbrev.: enol complex) and 2-hydroxypyridinium acetate (abbrev.: cation complex) which were speculated to form in the keto-enol tautomerization process of the 2-pyridoneacetic acid system in the ground state. The calculated results suggest that the keto-enol tautomerization may occur in the 2-pyridone formic acid system used as a model system from the magnitudes of the stabilization energies of the keto and enol forms and the potential energy height of the tautomerization process through the cation form.
Experimentally, the characteristic bands ascribed to the keto, eno l and cation complexes were observed in the IR spectrum of the 2-pyridoneacetic acid system. These results suggest that the ketoenol tautomerization may occur in the 2-pyridoneacetic acid system through the cation complex in the ground state.

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Solid solubilities in the 2, 2'-bipyridyl biphenyl eutectic system at the eutectic temperature, which correspond to the maximum solubilities, were determined by means of DSC, zone melting and thermal microscopic methods. In this system the relationship between eutectic enthalpy of fusion determined by DSC and composition led to the following straight lines:
ΔH₁^e=35.53x₂-2.037
ΔH₂^e=32.17x₂+ 31.302
where x₂ is the mole fraction of 2, 2'-bipyridyl;
ΔH₁^e and
ΔH₂^e are the eutectic enthalpies of fusion on the 2, 2'-bipyridyl and biphenyl sides from the eutectic composition, respectively. Putting
ΔH₁^e=0 and
ΔH₂^e= 0 in the above equations, the maximum solid solubilities were found to be x₁^es= 0.0270 and x₂^es= 0.0573 by mole fraction for the 2, 2'-bipyridyl and biphenyl sides, respectively. Moreover, eutect ic composition was found to be x₁^e= 0.493 by putting ΔH₁^e=ΔH₂^e. On the other hand, solidus curve in the biphenyl side was determined from the equilibrium distribution coefficient of 2, 2'-bipyridyl in biphenyl derived from zone melting experiment, and also the value of x₂^es was found to be 0.0705. By the use of a thermal microscope the solid solubilities were found to be x₁^es= 0.0192 and x₂^es=0.0603, respectively. I Studies of the Zone Melting. Part 9.

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A new reaction model was constructed and its behavior was studied, in which an optically active state appears spontaneously. The reaction model contains a stereoselective complex formation between a chiral catalyst and a substrate, and an optically active state appears spontaneously when a steady state of L=D is unstable. On the other hand, no optically active state appears for an achiral catalyst.

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Hydrous sodium aluminosilicate was formed when mullite powder of high purity prepared by alkoxide method was hydrothermally treated with sodium hydroxide aqueous solution. The hydrous sodium aluminosilicates were mainly composed of 1.08Na₂O Al₂O₂.1.68SiO₂.1.8H₂O and Na₁₄Al₁₂Si₁₃O₅₁.6H₂O in spherical grains. Successively, a small amount of Na₃Al₃Si₃O₁₂.2H₂O was obser ved at the final stage. The ratio of Al₂O₂/SiO₂ in the mullite had an influence on the kind of products besides treatment temperature and time. ICP (Induced coupling plasma) analyses indicated that more Al in the mullite was dissolved into the solution than Si. At the beginning of reaction, boemite was precipitated. The SiO₂ rich mullite was positively formed Na₆Al₆Si₁₀O₃₂.12H₂O instead of boemite.

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Many enzymes are reported to be dissolved in natural waters, and most of them are believed to be released by organisms living in situ. In these days, enzymes are used in industrial products such as detergents, but the behavior of these enzymes is unknown. We studied behavior of endopeptidase activity possibly dissolved in natural waters, since endopeptidases are now artificially added to detergents. For assay of endopeptidase activity, succinyl-L-Ala-Ala-Pro-Phe-P-nitroanilide was used as a substrate, and reaction product, p-nitroaniline, was monitored by spectrophotometrically at 380 nm at 30°C. The detection limit of the present method was 100 mU dm^-3(1 U =1 μmol min^-1). Endopeptidase activity of commercial detergents tested is 6.4-11 U g^-1. Their activity was completely inhibited by addition of phenylmethanesulfonyl fluoride (known as an inhibitor of serine proteases), and partly inhibited by addition of ethylenediaminetetraacetic acid (known as an inhibitor of metal proteases). Activity is preserved when the detergents were dissolved in river water than in pure water. It was suggested that enzymes added to detergents could be kept active in natural waters for days particularly in winter time. The activity level in river waters is lower than the detection limit by the present methods. Thus more sensitive methods must be developed to determine endopeptidase activity dissolved in river waters.

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As a trial to enhance activity of bioactive peptide, the dendrimeric formation of mastoparan (MP), a wasp venom toxic peptide, was carried out. We synthesized dendrimeric MPs consisting of 2, 4 and 8MP molecules formed on a branching lysine-core, and examined the hemolytic and catecholamine releasing activities and the circular dichroism. The activities of dendrimeric MPs were higher than that of MP and the a-helical contents increased with the increase of the number of branches in the dendrimers. The most potent dendrimer in hemolytic activity, approximately 8000 times as active as MP, was octameric MP which took 35% α-helical content even in an aqueous buffer. Our results indicated that the dendrimeric formation of an amphipathic peptide should be a useful way to obtain highly active peptide as shown already in immunogenicity.

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The dehydrogenation of C₃H₈ and the reduction of CO₂ were carried out simultaneously using Rh-added V₂O₅/SiO₂ catalysts. The addition of Rh to V₂O₅/SiO0₂ and the presence of CO₂ in the reactant flow increased the yield of C₃H₆ at the steady state of the reaction. CO₂ may be utilized as an oxidant for the reaction and/or may be used to remove produced carbon by reverse Boudouard reaction. In particular, the addition of very small amount of Rh (0.1 wt%) was effective to increase the effect of CO₂ addition.

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The anhydrous aluminum sulfate powder composed of rhombohedral single-crystal grains was prepared by precipitation from a concentrated sulfuric acid solution. The average grain size and the size distribution was 3.8±0.7μm. Thermal decomposition behavior of the anhydrous aluminum sulfate was investigated by thermogravimetric measurements. The kinetics of the thermal decomposition fitted to a contracting volume model with an apparent activation energy of 360 kJ/mol. The mobility of the reaction boundary of the thermal decomposition at 760°C was estimated to be about 7.0×10^-5μm/s. The temperature dependence of the mobility was expressed by an Arrhenius type equation.

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The difference of the reactivity for S_N2 type oxirane ring opening of exo and endo Aflatoxin B₁ (AFB₁)8, 9-oxide (exo-1 and endo-1, respectively) was analyzed with ab initio molecular orbital theory. All stationary points including transition-state structures were optimized with no geometry constraint at the RHF/3-21G basis set, and energies were evaluate at Becke3LYP/3-21G level based on the RHF/321G geometries. The caluculation clarified the following three points: (1) the activation energy (ΔE≠)for endo attacking of NH₃ molecule (the reaction with exo derivatives containing exo-1) is considerably smaller than those for exo attacking (the reaction with endo ones containg endo-1) (2) the reactivity for nucleophilic oxirane ring opening is controlled by the distortion of LUMO_c-o of oxirane ring, which is probably caused by exo/endo relationship between oxirane ring and five-membered dihydrofurano ring (B) with respect to A ring, and (3) the remaining part (inclusing coumarin skeleton) of AFB₁oxide has little influence on the geometry around the reaction center and the activation energy.

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