摘要:

The etching of iron whiskers in picral and nital etchants has been studied and etch‐pit configurations in certain areas of as‐grown whiskers have been observed. Dislocations introduced by plastic deformation of the whisker have been investigated and arrays of dislocations produced by annealing the deformed whiskers have been studied. Whiskers with axes in [100], [110], and [111] directions have been used in these experiments.

ISSN:0021-8979    

DOI:10.1063/1.1722974

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

The diffused minicrystal process yields a germanium driftp‐n‐pbar‐type transistor structure that has fewer practical limitations on emitter, base, and collector resistivities and on base width, than other processes used to make transistor bars for use in high‐frequency transistors. Unneutralized power gains greater than 40 db at ½ mc have been commonly attainable with transistors made using bars having 0.1‐mil base widths. Although thep‐n‐pbars are inherently usable to very high frequencies, base lead overlap capacities have thus far limited the application of early developmental units in this region.

ISSN:0021-8979    

DOI:10.1063/1.1722975

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

Unique crystal growth patterns with closed loops, partly concentric and partly eccentric, with very large step heights between the ledges were observed on microblisters of copper films sputtered onto glass substrate. While the primary cause for the generation of the blisters is explained as due to diffusion‐oil deposits present on the glass substrate and to heat from secondary electrons released by the target producing a high vapor pressure underneath the sputtered film, the generation of the loop patterns on the flat circular surface of the blisters is considered to be caused by alternative slips induced by the inside pressure which affect a triangular part of the {111} surface with two sides of {111} slip planes, one in radial <110> direction and the other in a <110> direction along the rim of the blister. Two alternately generated monatomic radial steps on the flat part of the blister produce two superposing spirals of opposite sense each due to one‐half of two Frank‐Read sources and create by repetition of this process the observed patterns with very large step heights of the ledges.

ISSN:0021-8979    

DOI:10.1063/1.1722976

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

The dynamic viscosity and rigidity of concentrated solutions of polyvinyl alcohol samples having different molecular weights have been measured by means of a torsionally oscillating rheometer and an electromagnetic transducer within the ranges of frequencies from 0.08 to 400 cps and the temperature range from 20° to 55°C. The solutions behave almost as Newtonian liquids at lower frequencies; however, at the frequencies around 1 to 10 cps the viscosity of solutions begins to decrease while the rigidity increases rapidly. The frequency at which the rather abrupt change in dynamic viscosity and rigidity takes place is lower the higher the concentration, the higher the molecular weight, and the lower the temperature. The effects of the concentration, temperature, and molecular weight on the zero shear (frequency) viscosity have been examined quantitatively, and some of characteristic features observed on other high polymers have also been found. Comparison of the dynamic voscosity with the steady‐flow viscosity shows that the frequency dependence of dynamic viscosity is not quite quantitatively equivalent to the rate of shear dependence of steady‐flow viscosity. The dynamic data have also been compared with two molecular theories of viscoelastic behavior of high polymers, and showed rather good agreement. A slight discrepancy observed in this comparison may be attributed to the molecular weight distribution in the sample and intermolecular interlacings in the concentrated solution.

ISSN:0021-8979    

DOI:10.1063/1.1722977

出版商:AIP    

年代:1958

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1722979

出版商:AIP    

年代:1958

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1722980

出版商:AIP    

年代:1958

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1722981

出版商:AIP    

年代:1958

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1722983

出版商:AIP    

年代:1958

数据来源: AIP