The decay of emission by ion bombardment and the recovery after termination of the bom-bardment are measured and the recovery characteristics are analyzed theoretically. A cathode, for which carbonate alone is used as barium source, is found to increase its work function from 1.65 eV to 1.8_??_1.9 eV and to improve its activity after being bombarded by argon ions and aged by heating thereafter, from which facts it is inferred that the lower value of the work function is due to adsorbed oxygen on the surface of the cathode.
For determining the viscosity of liquid by the use of Hagen-Poiseuille's law, there are two methods: the constant pressure difference method and the constant flow method. The former encounters difficulties in keeping the constancy of pressure difference. By the latter method and with an original device for maintaining the flow constant, the viscosity is measured continuously and accurately. Construction of this viscometer and results of measurement are shown.
The study on frequency-dependence of mechanical properties of polymers is well recognized to be of both practical and theoretical values, but few methods of observing the dependence in the frequency range of 1 to 20 c/s have been reported. An apparatus incorporating a forced vibration torsion pendulum has been devised by the author for the measurement of dynamic rigidity and viscosity of polymer films within the above frequency range. For obtaining better accuracy con-cerning the frequency, electronic counter is introduced into the measuring circuit. The resonance method is adopted, for the frequency-amplitude curve was very sharp. The apparatus and the method of calculation are explained in detail, and the accuracy of obtained data is examined. Results of measurement made on some coating films are given as examples. Experimental errors in measuring the rigidity of coating films that have a small loss tan δ (ca. 0.01) were 10_??_15 percent and those on the viscosity were 10_??_20 percent. The date thereby obtained were free from the effect of the load that hung at the lower end of the sample film.
A study on viscoelastic properties of phenol resin-polyvinyl butyral (PVB) mixed films has been made over a wide temperature range by means of the vibrating reed method and dielectric method. Two mechanical dispersions due to PVB mixed in the film can be easily observed; these dis-persions are influenced by the baking condition, the ratio of PVB to phenol resin and the types of both resins. From the relation between the magnitude of these dispersions and PVB content in the film, it seems most reasonable to conclude that one of these dispersions is due to the second order transi-tion of PVB itself and the other one to the existence of some graft or network structure which is formed by chemical reaction between PVB and phenol resin during baking process. A model to explain the dispersed state of the mixture is proposed from the results of measure-ments on the mechanical and dielectric properties of the films.
Luminescent properties of commercial ZnS(Cu) electroluminescent powder are investigated under different excitation conditions: photo-excitation with 254mμ and 365mμ U. V. light and electrical excitation with sine wave voltage. The differences in luminescent properties, especially the difference in intensity ratio of blue to green bands and in the temperature dependence of the ratio, caused by these different excitation conditions are explained by the excitation mechanism in each case. The spectral distribution by 254mμ light excitation is typical of host excitation: photons are absorbed in the host lattice and free electron-hole pairs are produced. On the other hand, 365mμ light excites directly only the blue centers. Temperature dependence of the spectral distribution in the latter case shows the existence of some thermal process in which the energy is transferred from excited blue center to green center. However, this process does not seem to be the simple hole migration process. Under A. C. voltage excitation, electroluminescence spectrum is characterized by the frequency and decay time of the emission. Decay time of blue center (about 0.42 msec.) estimeted from frequency dependence of the emission agrees fairly well with that measured by photo-excitation. Although this effect may explain the electroluminescence spectrum at low temperatures, interaction between the centers mentioned above for 365mμ excitation must be taken into consideration for the electroluminescence at room temperature or thereabout. Concerning this mechanism, details are not yet known.
The surface structures of butter and fat fraction obtained by molecular distillation of butter are observed electron-microscopically. Replica films of the surfaces are obtained by means of shadowing of chromium and carbon at-40°C. The apparatus employed is one similar to that reported by Hibi et al; it enabled the observation of surfaces at low temperatures. On the surface of butter, which is cracked, crystals with rhombic shapes are agglomerating together, growing with the lapse of time at low temperature. However, on the surface of fat fraction distilled from butter fat, miceller patterns are observed instead of rhombic shaped crystals, while on the surface of butter fat distilled at 270_??_290°C, thin layers are seen piled up. X-ray diffraction spectra of these specimens obtained by Geiger flex are compared with the outcome of electron microscopic observations, but no reliable correspondence between the two could be obtained. The intensity distribution of spectrum suggests that most parts of crystalline component in butter are tri or di glycerides of palmitic acid, oleic acid and stearic acid.
In the usual luster mensuration, luster is being measured without differentiating its quality and quantity. The writer discriminates the one from the other as Quality of luster: the characteristic based upon the distribution of reflection from parts of surface which are very small to the extent that the resolving power of the eye comes into question. Quantity of luster: the macroscopic characteristic based upon the average reflection from a reasonably large area of the surface which is regarded as uniform in luster. On this basis, an automatic recording micro-luster meter has been devised to measure the quality of luster and an analytical formula is derived for the recorded curve to evaluate quality L as _??_ where h: mean height of peaks, l: mean height of valley bottoms, D: distance between specimen and observer, p: mean distance between adjoining peaks, θ: visual angle subtended by peak and adjoining peak. The above formula gives for example the value of L of silk (3.18×102) larger than that of cotton (1.40×102). The value L needs to be within the range of 200_??_104 for the luster to be of good quality; if otherwise, surface pattern of the specimen, say a texture, either shows up too conspicuous or becomes indistinct by overall gloss.