For improving oil recovery by the reverse combustion, it was tried to reduce theamount of cork as a product of thermal decomposition reaction, using catalysts. KC1, CaCl₂, FeCl₂, NiCl₂ and MgCl₂ were selected and each water solution was injected into a sand pack as an oil reservoir in each run.
First of all, the effects of catalysts were examined by a thermogravimetric analysis and it was found that KCl1 used with silica sand grains was most effective. Then, combustion tube tests were carried out using KCl, to investigate the improvement of oil recovery and the whole behavior of reverse combustion. And it was found that the oil recovery of 51 percent without KC1 was increased to 60 percert with KC1 and the amount of cork remained was decreased from 38 percent without KC1 to 30 percent with KCl.

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An effect of uneven packing structure of a powder bed is investigated on a permeability diameter of a particle or a pressure drop of air across a packed bed. Compacting a compressible powder from above a cylindrical vessel, a distribution of solids pressure gives rise to that of void fraction as well. As a result, the diameter of the specific surface is appreciably underestimated from the overall voidage of the compacted sample. Thus, the corrective way for the true diameter is theoretically derived on the basis of the consolidating properties of powders.

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The encapsulation of a fine inorganic powder with polymer was carried out by heterogeneous polymerization of methylmethacrylate in water in the presence of powder. The effect of methods of monomer addition on the encapsulation state and coated polymer thickness was investigated experimentally. The encapsulation state with polymer was influenced remarkably according to methods of monomer addition. The thickness of coated polymer increased with an increase in the amount of monomer added. The addition of monomer continuously or little by little to the reaction system and keeping the concentration being less than the saturated solubility was found to be effective to increase the thickness of coated polymer.

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Gallium nitride (GaN) epitaxial layers are grown on oe-Al203 (0001) substrates, by using a hydride vapor-phase-epitaxy method. Surface morphology, crystal structures and electrical properties of the films are investigated in respect of the growth conditions. Surface morphology of the films depends upon the growth temperature and the ratio of the reactive gas flow rates. Relalively smooth surface is obtained when the NH3 flow ratio is large, and its electrical properties are also good. The optical band gap of the films with smooth and transparent surface is about 3.4eV.

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Oxygen-containing-copper is embrittled when it is used in a hydrogen atmosphere.Even if it is not embrittled, it is inferior in twisting and flexing properties to oxygen-free-copper. Flex life test is standardized at present for the identification of oxygen-containing-copper and oxygen-free-copper which has various merits. In this paper, this present condition was reviewed, i.e., these coppers were identified by the change of electrical resistance, and these coppers' physical changes were also observed. In addition, special phenomenon shown by electrical resistance of hydrogen-embrittled-copper and its inner microstructure were considered.
Summary is asfollows:
1) By grasping the change of electrical resistance, process of hydrogen embrittlement could be understood with real time
2) Also, redox of hydrogen-embrittled-copper could be grasped by the change of electrical resistance.
3) Temperature coefficient of hyddrogen-embrittled-copper became larger than the theoretical value. As for oxidized copper after hydrogen embrittlement, temperature coefficient became larger than that of hydrogen-embrittled-copper. However, electrical resistance value of hydrogen-embrittled-copper at room temperature was the same as before embrittlement.
4) A physically interesting, unique phenomenon was found, i.e., volume resistivity in appearance became higher by the hydrogen embrittlement, but the electrical resistance of the line type copper in the length became lower than before embrittlement.

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TiO2 and TiO₂-SnO₂ thin films were prepared by sol-gel method using the metal alkoxides (Ti (O-i-Rr)₄, Sn (OEt)₄). These films have been successfully prepared in low temperature of about500°C. The electrical properties are semiconductive. A humi: dity sensor with TiO₂ and TiO₂-SnO₂ films was prepared to use at high relative humidity above 60%RH.It is found that a response property of the sensors for the time is very fast between30%RH and90%RH as compared with that for other sensors.

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Fine powders of the composition Bi₁.6Pb_0.4Ca₂Sr₂Cu₃O_x have been prepared by the spray-pyrolysis method. The particles were spherical and their diameter was uniformly-distributed at about 1.5, μm. The body sintered from these powders at 840°C showed the offset of superconducting transition at Tc=104 K. Furthermore, the thick films have been prepared on a Ag plate or between two Ag plates using the powders. The powders were pressed on a Ag plate or between two Ag plates at 200kg/cm² and heat-treated at 855°C for 30 min. The resultant films on a Ag plate were again heat-treated at 840°C for 62 hr after the cooling to room temperature. The thick films obtained showed the offset temperature of 104 K. On the other hand, the films sandwiched between Ag plates, which were heat-treated also at 855°C for 40 hr after the cooling, showed the offset temperature of 80k

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The latest process of partial melting for the fabrication of bulk YBa₂Cu₃O_7-x superconductor with high critical current density (Jc) has been developed.
The specimen prepared by the partial melting process shows Meissner effect as well as Suspension effect. The calculated Jc from magnetization measurement has been indicated as 7.9×10⁸A/m² at 77K under zero magnetic field and 4.3×10⁸A/m² under 0.1T, and been more than ten times as high as the Jc of sintered specimen.The reason for high Jc especially under magnetic field is founded that YBa₂Cu₃O_7-x phase formed by peritectic reaction in the matrix YBa2Cu3O7-x functions as the pinning center.

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Powder mixing is widely used in chemical industries and also is taken to be one of the important problems to be elucidated. Especially, the homogeneous powder mixing operation is expected to be urgently developed in the field of fine ceramics, powder metallurgy and pharmacy industries, etc.. This homogeneity can be evaluated by the simultaneous measurement of powder porosity and powder mixing ratio. However this simultaneous mesurement method has not yet been sufficently developed up to now.
Then from this point of veiw, a new simultaneous mesurement method about two components of mixing powder is presented and its validity is experimentally and successfully checked by use of five kinds of test powders, such as silicon carbide (: SiC # 100), alumina (white), alumina (grey), teflon and polystyrene. And the simultaneous mesurement method is applied to evaluate the mixing performance of V-type mixing with and without electrostatic effect. As the result of it, excellent powder mixing performance is pointed out to be obtained by the application of electricity.

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The X-ray diffraction intensity corresponding to the basal plane reflections, from (001) to (005), for nickel intercalated montmorillonite was measured as a function of nickel content. The intensity of these five lines changed systematically as the nickel content increased. On the other hand, the composition-dependence of the line intensity was theoretically calculated on the basis of the structure model that nickel hydroxide monolayar fills gradually in the interlayer space of montmorillonite on the various steps of intercalation reaction. The experimental results were found to be consistent with the calculated intensity. However, some differences were also found, which was discussed in terms of adsorption site difference of nickelions.

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In the design of a hydraulic breaker, it is necessary to take the properties of blowed materials into consideration because the properties have infuluence on the performance of hydraulic breakers. In order to clarify the effect of the materials-properties, an experiment has been organized for evaluating the performance of a breaker. In the experiment, three kinds of hard rubbers have been used for simulating the properties of materials which are broken by breaker.
The following results have been obtained.
(1) The rate of the energy-absorptive-power for the materials, which is calculated from the blow velocity and the repel velocity of the piston, increases linearly as the supply flow rate and the tate of the supply-flow-energy are increasing.
(2) As the rate of energy-absorptive-power is increasing, the blow velocity of the piston increases. but the efficiency of the oil hydraulic breaker decreases.
(3) The blow rate increases as the rate of the energy-absorptive- power is increasing. The harder the blowed rubber becomes, the more the blow rate increases. Under the constant supply pressure, the blow rate decreases as the hardness of the blowed rubber is decreasing.

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In this review first the factors affecting the stability of suspension of ferromagnetic particles, under magnetic field gradient, gravitational field, and against magnetic agglomeration and van der Waals attraction are discussed. Then, an attempt has been made to review various magnetic fluid preparation methods and the progress made in each of them. Finally, the properties of magnetic fluid are discussed.

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