Surface roughness is an important factor for the estimation of machining process and functio-nal properties of machined surfaces. Problems on a standardization of numerical evaluations of surface roughness and surface waviness and progress on measurements, indications and instruments of surface roughness are described. Finally, some models on the machining process are reviewed.
Some direct reading specific gravity balances have already been devised. The specific gravity balance here reported is a kind of such balance which enables us to measure the specific gravity of a liquid directly with an accuracy of ±0.0001. It is a remarkable feature of this specific gravity balance that the sinker does not have to be of the assigned volume to a high degree of accuracy and the hanging point of the sinker can be finely adjusted according to the volume. The hanging point of the sinker may be adjusted experimentally. The specific gravity of water at various tem-peratures have been measured with this balance, the experimental results agree fairly well with the values given in physical tables. The specific gravity obtained with this balance takes account of the houvancv of air.
Stimulated emission from 19 polymethine dyes dissolved in organic solvents and pumped by a Q-switched ruby laser is reported. In this experiment, 5MW output power and 20% conversion efficiency have been obtained. The wavelength of laser emission varies with the concentration of dye solution within several tens of mμ. Varying the concentration of these polymethine dyes, high power laser emission (>1MW) has been obtained practically throughout the entire wavelength range from 710mμ to 1060mμ.
The linear electrooptic coefficient at constant stress r41T of ZnTe:In was measured at room temperature by means of the Senarmont compensator method. Wavelength of the incident mono. chromatized light used in the measurement is from 6000Å through 6400Å, and an ac electric field of 50Hz is applied to a crystal. Measured values of r41T are, for example, 4.9×10-12m/V at 6000Å, and 4.3×10-12m/V at 6400Å. Half-wave voltage has been found as low as 2.2kV at 6000Å which is comparable to those of KD2PO4, LiNbO3 and LiTaO3. This low half-wave voltage, together with the fact that ZnTe is a cubic crystal which is advantageous for light modulators, suggests the usefulness of ZnTe for light modulators and similar devices.
Pressure dependence of the absolute thermal emf of alumel has been determined by means of an opposed anvil type high pressure device, under a temperature difference of 100°C between top and bottom anvils at pressures up to 130 kbar. Since, with a solid-pressure apparatus of the present configuration, large shear stresses and plastic deformations are expected to develop in the pressure medium, correction has to be made for a plastic strain effect on the thermal emf. The thermal emf due to this effect increases with a rate of 0.43μV/100°C/kbar up to 25 kbar, beyond which pressure it remains constant at lOμV/100°C. This tendency was confirmed by tension and compression tests on alumel wires. The thermal emf is increased by pressure taking a positive slope of 1.2μV/100°C/kbar with negative curvature and amounts to 88μV/100°C at130 kbar. An error due to the nonuniform distributions of both temperature and pressure in the pressure cell is estimated by Hanneman's method.
The liquid SeOCl2: Nd3+ laser of high quality is described. Purification of SeOCl2 was carried, out by a zone refining method. The anhydrous NdCl3 was dissolved in a mixture of SeOCl2 and SnCl4, and the latter was removed by evaporation. The lifetime of excited 4F3/2 level of Nd3+ in the solution thus obtained was measured to be about 180μs. Laser action at 1.0560μm was observed under various conditions. It is found that the “solvation shell” does not play an effective role in the fluorescence of Nd3+ in SeOCl2.
It is well known that a rotational ellipsoidal mirror has excellent properties of increasing pumping efficiency and giving uniform excitation of a laser cavity, but it is not widely used because of difficulties in fabrication. We developed a method by which mirrors of arbitrary excentricities and dimensionscould be easily made by setting up a simple attachment to a conventional lathe. In this paper, the method will be described in detail.
Since the band gap of InSb is slightly less than twice the photon energy of CO2 laser (0.11 eV), photoconductivity should be observed at 10.6μ through double photon absorption. Photoconduc-tivity of sufficient sensitivity and good time response have been obtained in p type InSb by exciting it by a Q switched laser at liquid nitrogen temperature. It was found that the dependence of conductivity upon laser intensity was the result of the super-position of impurity and double photon processes. This phenomenon is interesting in the investigation of the energy structure of InSb and also noteworthy as an application for high speed response detection near 10μ.