Platelets, ribbons, and needles grow from the vapor phase by the dislocation mechanisms-The variety of crystal habits can be attributed to the difference in dislocation structure of the growing crystals. The crystals are highly perfect with respect to line and two-dimensional im-perfections, because the dislocations tend to slip out of the crystals after the growth. With regard. to dislocations in CdS, 1/3 <2110>, <0001> and <1010> Burgers vectors have been found by x-ray diffraction microscopy and etching method. The stability of dislocations in thin crystals is dis-cussed. The α and β-dislocations have the different effects on the optical property. Stacking faults have been observed only in impurity-doped crystals, and some of them seem to be formed, by extending of 1/3 <2110> Burgers vector dislocations. Stacking faults and prismatic faults are frequently present near the growth front of impurity-doped platelets. In the impurity-doped crys-tals, disk-shaped precipitates are formed easily parallel and close to the crystal surfaces. It was found by x-ray moiré patterns that an uniform impurity distribution causes an extremely small change of the lattice parameters.
When Hall generator is used for making an analog multiplier with transistorized amplifiers, it is desirable that the temperature variation of Hall voltage is small and the sensitivity S≡vh/B•i=RH/t is large, where vh is Hall voltage, B is a magnetic flux density, i is a control current, RH is Hall coefficient and t is a thickness of Hall generator. By diffusing an n-type impurity into p-type Ge of high resistivity, a thin layer of low resistivity can be produced. This structure fulfills the requirements for a temperature independent and highly sensitive Hall generator. The properties of the generator of this structure are discussed theoretically and experimentally and they are compared with those of bulk semiconductors.
It has been said that the X-ray output of a betatron is decreased by1/2_??_1/3 placing a peeler of ferro-magnetic material in the donut. The reason is that it disturbs the magnetic field on the electronic orbit, and many electrons strike it and get lost before they are accelerated. But, by placing a peeler very close to the outside wall of the donut, much more X-rays than before are obtained. The peeler used here is a pipe of Fe-Co alloy, which is easily supported. For producing electron beams, the electronic orbit is expanded outward and at thesame time shifted toward the peeler, so that the most of electrons clear the electron gun and enter the opening of the peeler. Dose-rate of 24 MeV electron beams is about 1000 r/min at 1m from the center line of the magnet, which is excitedby 60c/s A. C.
The shock response of a nonlinear single-degree-of-freedom system issometimes analytically determined by two straight lines. Response spectra for the step excitation with various amounts of drop heights are due to the damping ofmaterial, and the values of displacement and velocity at the end of the first phase yield the initial conditions for the second phase. If the spring constant of the second linear element is not equal to zero, the solution of the second phase is obtained analogous to the first one by displacing their parameters. Displacement and acceleration spectra obtained by experiment are nearly coincident with values calculated on the assumption of ξ=ζ.
When an epitaxial layer of N-type is grown on surface of a conventional shape oscillistor made of P-type Ge, oscillistor oscillation is hardly excited and the resistance remains almost unchanged even in the presence of the magnetic field. When the grown layer is removed, the sample resis-tance changes greatly and the oscillistor oscillation of large amplitude can be excited quite easily in a locally concentrated magnetic field. The results indicate that the PN layer on the surface has a quenching effect on oscillister oscillation.
Several kinds of dry powder of known mass are used to examine the effect of various methods of filling them into glass cylinders. on the packed volume. The filling of powder under a given condition is repeated ten times to find the fluctuation of packed volume specific to the used meth-od. In general, the fluctuation is less as the packing is denser. Slight vibration, especially when applied horizontally, gives the best reproducibility although the packing is not very dense. Tapp-ing is effective for dense packing, but it does not give good reproducibility. Tapping by hand is most likely to cause considerable fluctuation.
The compacting behavior of various kinds of dry powder by tapping and vibration is studied. This behavior can be classified into two types: (1) The reduction rate of porosity decreases slowly with increasing number of repetition of tapping or vibration. (2) A major part of porosity disap-pears at very early period of tapping or vibration. The compacting behavior of the first type fits in well with Kawakita's equation C=(abP)/(1+bP), where C is relative reduction of volume, a and b are constants. In application of this equation, the pressure P is replaced by tapping number N or vibrating time t. In the case of the second type, the observed data agree best with Nutting's equation (ε=φ-1t_??_ƒβ; ε, volumetric strain;, φ, k, β, constants), if the stress ƒ is taken to be a constant and the observed time t is replaced by tapping number N or vibrating time t.
The temperature characteristic of viscoelasticity of novolac and novolac-type crosslinked resin is studied over a range of temperatures between -180°C and 150°C. Three dispersions α, β and γ in the orderof descending temperature exist in these polymers. Increase in degree of cure in-creases the β-loss and decreases the γ-loss. Wood flour filled in crosslinked resin shifts β-disper-sion towards the lower temperature. There is a linear relation between the temperature at which β-loss peak appears and the concentration of wood flour. Wood flour also seems to decrease the γ-loss. On the other hand, the filling with glass powder makes no change on the temperature characteristic of loss tangent. It is considered that the β-dispersion is attributed to a motion of main chain of the resin molecule and the β-dispersion to the phenolic groups at the end of cross-linked structure.
Characteristics of a new type cold cathode which consists of porous MgO and Ag layers are described. After appropriate heat treatment, δ and SSE of this cathode become 103 and 6mA/cm2 respectively. The reason of obtaining such high gain may be explained by the establishment of parallel electric field in the pores of MgO layer due to the local deposition of Ag on the surface of MgO grains.