Effects of explosive shock treatment in the range of about 5 to 90GPa on the characteristics of TiO₂ and ZrO₂ powders were examined.
The explosive shock caused anatase-rutile transition of TiO₂ and caused the transition temperature to lower. This transition was found to enhance the sinterability of TiO₂ powders. The densification during the course of the transition was prohibited by the explosive shock treatment, and the density of sintered body of anatase TiO₂ for explosive shock became lower than that of the as-received powder. Explosively shocked rutile TiO₂ powder, on the other hand, showed higher sinterability than that of the as-received one probably because of smaller crystallite size and residual strain in the shock-treated powders.
The weight fraction of the tetragonal phase of ZrO₂ increased with the impacted pressure up to 20GPa but decreased at the pressure of 40 and 90GPa.
The crystallite sizee stimated from the X-ray diffraction profile of both powders became smaller with the increase in the impacted pressure. Auresidual strain of explosively shocked TiO₂ was present but was virtually absent in the ZrO₂ powder.

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Adaptation of the natural phenomenon of drop formation has resulted in the development of forming seamless capsules.
By means of a concentric nozzle system, seamless capsules in the diameter range from 0.5 to 20mm can be continuously produced.
The influence of physical factors on the conditions to produce capsules was investigated experimentally.
The results are summarized as follows;
1) The diameter of formed capsules is about twice that of the liquid jet and is equal to the diameter of the liquid droplet which was calculated from Dabora's equation.
2) The presence of optimum flow conditions for the formation of uniform size capsules was elucidated.
3) The diameter of produced capsules increases as the pitch of capsule formation increased and decreases as viscosity of the shell liquid increased.

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The amorphous state of drugs was obtained by the grinding of drugs with cyclodextrins. The dispersed state of the drug molecules in the ground mixtures was investigated by IR spectral analysis using α-, β-, γ-cyclodextrins and linear oligosaccharides. It was suggested that aspirin molecules were included in the cavity of β-, and γ-cyclodextrins by the grinding, while they were not included with α-cyclodextrin.
Solid state aspirin decomposition rates were measured in various aspirin-cyclodextrin systems. The decomposition rates of aspirin were related to the dispersed states of the acetoxyl group of aspirin molecules. When the acetoxyl group was in the free state, the system showed a slow decomposition rate. On the other hand, when it was hydrogen bonded with the hydroxyl group of cyclodextrin, the systems showed greater decomposition rates.
The effects of humidity on the crystallization of the ground mixtures with cyclodextrins were also discussed. Amorphous ground mixtures were changed into crystals when they were stored at a higher relative humidity (RH). The RHs in which the ground mixtures crystallized were correlated with the hydration numbers of the respective inclusion compounds.

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A tensile break-up experiment of green mold sands was undertaken. The green mold sands were prepared using various kinds of bentonite as a binder under different conditions of composition, mixing ratio, moisture content and aging period. On the basis of the data obtained, the molding and flowage properties of green mold sands were examined. The following are the results obtained.
1. A large tensile strength was obtained from the green mold sands that contained a binder mixed with activated bentonite by exchange of Ca cation with Na ion or a binder mixed with Ca- and Na-bentonite. This may indicate a higher molding property.
2. Prolongation of the aging period of Na-bentonite containing green mold sands produces high compaction of green mold sands and higher flowage.
3. By addition of approximately 70% uncalcined bentonite, used mold sands regain tensile strength almost as high as that of new green mold sands.
4. The tensile strength of green mold sands varies more with the amount of bentonite (binder) than with moisture content. The tensile strength in high-pressure molding also varies with the effect of the amount of bentonite.

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It was found that the tablet hardness linearly increased with increasing milling time without further decreasing the particle size of powder.
The above finding might be due to the fact that the tablet hardness was independent of the average particle size of the compressed powder, but it depended on the degree of destruction of the crystal lattice.
This was confirmed by the significant correlations between the tablet hardness and the relative intensity in the X-ray diffraction pattern and the maximum endothermic peak in differential thermogram.

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The silica gel was treated with the organ-silyl chlorides, i. e., trimethylchlorosilane, n-butylchlorosilane, l-chloropropyltrichlorosilane, phenyltrichlorosilane, phenylmethylchlorosi lane, diphenylmethylchlorosilane and chloromethyldimethylchlorosilane and the hexamethyldisilazane which react with surface silanol at room temperature, respectively. The identification and reactivity of the surface group and surface properties of the surface-treated silica gels were investigated from the microanalysis, ir-spectra, pyrolysis, dispersive properties and the surface reaction. The surface of silica gels treated with organo-silyl chlorides consisted of the organo-silyl groups of the reagents used, while the one treated with hexamethyldisilazane consisted of trimethylsilyl groups. These silica gels were hydrophobic. The Cl in the surface group of the silica gel treated with l-chloropropyltrichlorosilane or chloromethyldimethylsilane was easily displaced with an OH-groud by immersing it in NH₄OH aq. solution. The pyrolysis of the surface-treated silica gels occurred at a higher temperature than that of silica gels treated with alcohols, the amount of pyrolysis products was smaller than that of the latter. The silica gels after pyrolysis had an apparent deposit of carbon. Since HCl was not found in the pyrolysis products of that treated with organo-silyl di- or trichlorides, except for chloroalkylsilyl chlorides, the unreacted Cl included in reagents was found to be easily displaced with OH due to moisture in the air. The pyrolysis products of the silica gels treated with organo-silylchlorides, excep for chloroalkylsilyl chlorides, consisted of the corresponding olefine were included in the pyrolysis of the latter.

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In an attempt to quantify the mechanochemical activation of fine powdery materials, two characteristic values, the relative crystalinity, I_f, and the excess enthalpy, ΔH*, were obtained from X-ray diffractometry and calorimetry. PbCO₃ and γ-Fe₂O₃ were used as model substances and were activated by vibro-milling with different amplitudes in air as well as in cyclohexane. Applied work done during mechanical stressing was also measured on the principle of isoperibolic calorimetry. The rate of increase of ΔH* with decreasing I_f became larger with decreasing I_f. Compared at the same I_f, ΔH* was larger at larger amplitudes. This was presumably due to the formation of more intensive active centers than those generated by smaller amplitudes. The importance of accounting for the difference in the nature and distribution of active centers was emphasized.

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A modelling study of the non-catalytic gas solid reaction of a pellet accompaning sintering was conducted. A conservation equation of the particles forming the pellet was derived for movement due to sintering. The model can predict local void fraction distribution and shrinkage rate as well as the reaction progress of the pellet. From the computed results, the overall reaction rate of the pellet is found to be governed by the sintering rate, the initial pellet density and the soild reactant concentration. The reaction rate accompaning sintering decreases, compared with the rate without sintering. The decrease in the reaction rate can be explained by the decrease of effective diffusivity and effective reactive surface due to sintering.

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A spray drying method was applied to the recrystallization of phenylbutazone, and thee crystal forms of the resultant samples were examined by X-ray powder diffractometry, differential thermal analysis, IR spectrophotometry, scanning electron microscopy, and hot stage photomicroscopy. Three different crystal forms, i. e., Forms δ, β, and ε, could be prepared from methylene chloride solution by varying the drying temperature of sprayed droplets from 120 to 30° Form ε was confirmed as a novel crystal form which could not be prepared by recrystallization techniques and was the fifth polymorph of phenylbutazone. In this spray drying system the composition of spray-dried samples was a function of drying temperature. While the stable form δ was obtained at higher drying temperatures, Form ε was formed only under the condition of lower evaporation rate of the solvent.
The dissolution properties of pure polymorphic forms prepared by recrystallization techniques and the spray-dried samples were evaluated in a simulated intestinal fluid. Form ε showed the highest in-vitro availability and much higher solubility than that of any other forms.

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