Photoconductivity is measured on YIG as functions of light intensity, electric field, temperature and doping concentrations of Si⁴⁺ and Sr²⁺ The experimental results are summarized as follows:
(1) Shape of relaxation curves depends on the intensity of the exciting light and the decay time increases with light intensity.
(2) Dark current and photocurrent have a similar thermal behavior; both of them increase exponentially with temperature. This may be predominantly due to the thermal variation of the mobility of electrons, μ.
(3) Photocurrent is proportional to the intensity of light below approximately 250°K and at higher temperatures saturation begins.
(4) Spectral response of the photoconductivity shows a rise at shorter wavelengths of exciting visible light, corresponding to an absorption edge roughly in 5 mol% Si-doped YIG. Also, the subpeak of photocurrent at the photon energy of 1.4 eV roughly corresponds to the optical absorption peak.
(5) Photosensitivity Ps (the ratio of photocurrent to dark current) decreases with an increase of Si⁴⁺ dopant and increases with concentration of Ca²⁺ or Sr²⁺.

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The reasonable choice of an equation among the equations for the determination of self-diffusion coefficients from the data obtained by the capillary reservoir method is elucidated by developing an alternative form of the well-known equation. The obtained alternative form is proved to be identical theoretically with the well-defined equation. It is also shown by using the alternative form that the equation
(Remark: Graphics omitted.)
can be used at a lower value of \sqrtDt⁄l than 0.5₀ and that the equation
(Remark: Graphics omitted.)
can be valid at a higher value of \sqrtDt⁄l than 0.4₂.
The calculated value of self-diffusion coefficients of silver ion in pure molten sodium nitrate by an appropriate equation provide the validity of using the chosen equations at a given value of \sqrtDt⁄l. The obtained diffusion coefficient agrees well with the chronopotentiometric and polarographic diffusion coefficients of silver ion in pure molten sodium nitrate.

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Measurements of Young’s modulus and thermal expansion and of rigidity modulus and hardness (R.T.) have been carried out for Mn–Ni alloys subjected to a variety of heat treatment and cold working. The 10.15∼35.30% Mn–Ni alloys slowly cooled after heating at 950°C for 1hr showed a clear minimum or maximum in Young’s modulus-temperature curves. These anomalies may correspond to antiferromagnetic Néel points or fcc\ ightleftarrowsfct martensitic transformation. The value of Young’s modulus at room temperature was almost independent of cold working and heat treatment except for a large difference between the γ and the mixture phases on the Mn side. A remarkable minimum in Young’s modulus was also observed near 18.50% nickel. The temperature coefficient of Young’s modulus at room temperature depends largely on the heat treatment, cold working and alloy composition. When it is plotted as a function of composition, it exhibits a large maximum of positive sign and a minimum of negative sign. The highest positive temperature coefficient of the Young’s modulus in the annealed state is +119.50×10⁻⁵ for the alloy containing 20.30% Ni, thus exhibiting the Elinvar property. The rigidity modulus also exhibits a similar behavior. The values of hardness in the annealed, water quenched and reheated states were generally lower than that in the cold worked and reheated states.

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The alloy composition limits for transformation of the ordered bcc β₁ Cu–Sn phase to the β₁′ and γ₁′ martensites during quenching to 20°C and subsequent cooling to −196°C have been determined by optical metallography. It is shown that the limits are imposed by the variation with composition of the initial β₁ phase of the M_s and M_F temperatures for the transformations. In duplex structures the transformation behaviour changes with quenching temperature probably as a consequence of the temperature dependence of the Sn concentration in the β₁ phase.
An additional product, termed β′, formed in all alloys quenched from above some minimum temperature and was identified as martensite from relief effects which accompanied the transformation.

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In the specific heat curve of Cu₃Au ordered alloy, an unexpected bump is shown at about 320°C in addition to the order-disorder transition at 390°C. A similar anomaly has also been found in FeCo alloy at about 550°C, the origin of which is clarified by Yokoyama et al. We applied the same procedure as employed in FeCo alloy to Cu₃Au alloy with a face-centered cubic structure and investigated in detail the disordering process by measurements of electrical resistivity. Changes in resistivity as a function of temperature at the heating rates, 2°C/min and 20°C/35 hr (very slow rate), were also obtained by applying Bragg-Williams’ equation for the rate of approach to the equilibrium state. The anomaly at about 320°C does not occur in the equilibrium state, and it is considered to be caused by the heating rate too high compared with the diffusion rate, just as in the case of FeCo alloy.

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The dynamic deformation behaviour of copper single crystals (99.999% purity) and polycrystals (99.99% purity) were investigated by compression tests at room temperature and partly at liquid nitrogen temperature, using a bar-bar type impulsive loading apparatus. Strain rates studied were of the order of 10²∼10³sec⁻¹ for the dynamic test and 10⁻⁴∼10⁻²sec⁻¹ for the static test.
The time variation of the observed stresses at both ends of a specimen under dynamic test definitely shows the effect of plastic wave propagation. Crystals with orientations ranging from the middle to the [110]-[111] boundary in the stereographic triangle show higher critical resolved shear stresses and flow stresses and more extensive regions of stage I, followed by definite regions of stage II, under dynamic deformation than those under static deformation. The rates of work hardening of stages I and II are shown to be independent of strain rate. The strain rate dependence of the stress-strain relations for crystals with orientations near [100] and polycrystals is negligibly small. Microscopic observations show that there is no remarkable difference in slip markings between the dynamically deformed specimen and the statically deformed one.
It is concluded from the above results that in high strain rate deformation of copper single crystals, the influence of the frictional stress on moving dislocations becomes too large to be negligible, if the dislocation density of the specimen is fairly small.

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The strain rate and temperature dependence of the flow stress of copper (99.999% purity) and copper-manganese (0.1∼1.1 wt%) dilute alloy single crystals with the orientations suitable for easy glide has been investigated by compression tests over the strain rate range of 10⁻⁴ to 10³ sec⁻¹ and the temperature range of 77 to 373°K.
The critical resolved shear stress (CRSS) at room temperature gradually increases with increasing strain rate over the low strain rate range, but rapidly increases over the high strain rate range. At low strain rates the CRSS increases with decreasing temperature and increases nearly in proportion to the atomic concentration of manganese. On the contrary, at high strain rates the CRSS for pure copper and 0.1% manganese alloy scarcely varies with temperature, but rather tends to increase with increasing temperature. For 0.5% and 1.1% manganese alloys, however, it decreases with increasing temperature. The manganese concentration dependence of the CRSS at low strain rates and its temperature dependence at low temperatures are well explained by Friedel’s solid solution hardening theory. The temperature dependence for 0.5% and 1.1% manganese alloys at high strain rates is also explained qualitatively by the same theory. It is considered that the strain rate dependence in the low strain rate range is controlled by the non-conservative motion of jogs on moving dislocations. On the contrary, for the explanation of the magnitude and strain rate dependence of the CRSS for pure copper and 0.1% manganese alloy in the high strain rate range, the frictional resistance against moving dislocations from the crystal lattice should be taken into consideration. It is also presumed that the frictional resistance contributes considerably to the deformation of 0.5% and 1.1% manganese alloys crystals at high strain rates.

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The effects of alloying elements on the pitting corrosion of aluminum in an 1N–NaCl solution have been studied by using binary aluminum alloys containing different amounts of alloying elements, Fe, Si, Cu, Mg, Mn, Ni, V, Cr, B, Zr, Ti and Be. Anodic and cathodic polarization curves, pitting potentials, pitting dissolution currents and densities of pits at constant potentials were measured in the solution, and relations between the corrosion resistance and these properties of the alloys were considered. For increasing the resistance of the alloys against pitting corrosion, it was effective to add the elements which serve to increase the cathodic polarization. This is because the dissolution rate of the alloys in the immersion corrosion test was dependent upon the degree of cathodic polarization and independent of the anodic dissolution rate and the pitting potential.

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Vapor pressure of sulfur of sulfur-thallium liquid mixture was measured over the composition range of 0.55∼0.98 by mole fraction of sulfur. Although this mixture is much stable at the composition of Tl₂S, sulfur activity is quite high and its partial molar heat of solution is positive in the intermediate range. This result was interpreted in terms of a modification of the sulfur chain on addition of thallium.

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The kinetics of a fundamental reaction of the aluminum subhalide process, 2Al(l)+AlCl₃(g)=3AlCl(g), was studied by the flow method under a reduced pressure of trichloride at 900∼1100°C.
The reaction rate increased with the increase in the flow rate of trichloride, namely its pressure. As a result of the present experiment, the reaction rate was expressed by the following equation:
V=1.28P_AlCl3^4⁄3e^{−11800⁄RT} (Al g/cm²·min).
The apparent activation energy of this reaction was 11.8 kcal/mol. The reaction ratio of AlCl₃ increased with rising temperature and lowering trichloride pressure.

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The effects of iron, silicon, nickel and copper on the reaction of aluminum subchloride process were investigated by the flow method of aluminum trichloride at reduced pressure and in the temperature range of 900∼1100°C.
In all cases, the extraction rate of aluminum decreased with increasing contents of alloying elements, and increased as the temperature and supplying rate of aluminum trichloride were raised. The extraction rate of aluminum could be expressed by the following equation including the activity of aluminum and the partial pressure of aluminum trichloride.
V=1.28a_Al²·P_AlCl3^4⁄3·e^{−11800⁄RT} (Al g/cm²·min)
The contents of silicon and iron in the deposited aluminum were about 0.2% and 0.05%, respectively, and a minute amounts of copper and nickel transfered to the products. In addition, the experimental results were discussed on the basis of thermodynamic calculation.

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The extraction of aluminum was carried out by the subchloride process. The source material was the crude aluminum alloy prepared from colloidal earth and bauxite by the use of a 70 kVA electric furnace.
The extraction ratio of aluminum increased as the size of alloy particles is smaller and the supply of aluminum trichloride is larger, and reached more than 90% at 1300°C. Furthermore, its ratio depended not only on the aluminum content in the alloy but also on the Fe/Si ratio.
The reaction ratio of aluminum trichloride decreased with increase in its supply and decrease in temperature, but it increased when the reaction zone was extended.
The deposited aluminum contained small amounts of silicon and iron, in which the content of silicon was larger than that of iron. The purity of aluminum was higher than 99.6%. Furthermore, the extracted aluminum was melted and made into a thin plate by rolling.

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