摘要:

The conditions of self‐consistency for electron flow through arbitrary static or time‐varying electric and magnetic fields are established assuming (a) nonrelativistic flow, (b) single streaming–i.e., the velocity has a single value and direction at every point, and (c) the electrons originate on a cathode not threaded by magnetic lines of force. In the case where the magnetic field is constant and uniform, a single‐vector differential equation can be written which determines all possible solutions.From this equation certain time‐variant solutions are developed. These are fully self‐consistent–that is, large signal–solutions which exhibit some of the nonlinear behavior that would be expected of such solutions.Probably the most interesting of these solutions–since it offers an explanation of an observed phenomenon that does fit previous theory–is a radial oscillation of the cloud in a filamentary cathode smooth bore magnetron at&ohgr;/2.The possible application of the other solutions to anomalous behavior in various magnetron type devices is also discussed.

ISSN:0021-8979    

DOI:10.1063/1.1735421

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

The films of Cs&sngbnd;Sb alloys whose compositions were determined by the weighing method, were prepared at the temperature ranged from 70°C to 100°C. The electrical resistance and its temperature dependency of the samples, of which atomic ratio of Cs to Sb was ranged from 0.91 to 4.86, were measured. The reproducibility of electrical resistance was obtained for all the samples, except for Cs3.30Sb, and the temperature coefficients of resistance of the samples, except for Cs0.91Sb, were all negative. It was found that three compounds, CsSb, Cs3Sb2, and Cs2Sb in addition to Cs3Sb, having a remarkably high resistance, could be formed. The observed values of the electrical resistivity at 0°C and the thermal activation energy associated with conductivity were 1.84×103ohm‐cm, 0.61 ev for Cs1.02Sb; 1.82×103ohm‐cm, 0.76 ev for Cs3.02Sb2; 2.85×103ohm‐cm, 0.62 ev for Cs2.02Sb; and 1.95×103ohm‐cm, 0.77 ev for Cs3.33Sb. The alloys with atomic ratio above 4 looked gold in reflected light, and those with atomic ratio above 5 were not formed.

ISSN:0021-8979    

DOI:10.1063/1.1735422

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

The small angle scattering approximation of Schiff is applied to several nonspherical body shapes. Effects of orientation and elongation are discussed.

ISSN:0021-8979    

DOI:10.1063/1.1735423

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

Observations have been made at low temperatures of large discontinuities (steps) in the 60‐cycle hysteresis loops of polycrystalline ferrites containing copper. At the temperature for step formation, which is a function of copper content, the coercivity decreases and the loop squareness approaches unity. This behavior is attributed to the formation (in the toroidal specimens used) of circular 180° domain walls having different threshold fields. This domain wall configuration is probably brought on at low temperatures by a low effective magnetocrystalline anisotropy provided by the localized distortions exerted by divalent copper in the spinel lattice.

ISSN:0021-8979    

DOI:10.1063/1.1735424

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

The behavior of As in Ge containing regions doped with ∼5×1020/cc Al was studied. The solubility of As is enhanced tenfold or more by the heavy Al doping, on the basis of (1) measurements of conductivity type and (2) the negative results of a search for compounds by x‐ray diffraction. The behavior of As diffusion fronts was studied by observing the progress of thep‐njunction formed in Ge containing 1017/cc In. When a region of heavy Al doping was added, thep‐njunction was displaced. The displacements indicate that the diffusing As is attracted to regions of heavy Al doping. These results are similar to those of Reiss, Fuller, and others for Li in Si, though a detailed understanding is not yet available in the present case.

ISSN:0021-8979    

DOI:10.1063/1.1735425

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

Dislocation densities in CdS crystals (types I and II) have been investigated employing chemical etching techniques. There is very little difference in the dislocation densities in the two types of CdS crystals. The dislocation density in both types of growth varies over a range from 107/cm2to 101/cm2. However, type I crystals have a greater tendency to twin and low angle boundaries are generally present in the twinned crystal.

ISSN:0021-8979    

DOI:10.1063/1.1735426

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

The five independent elastic constants of beryllium have been determined with the pulse echo technique at a frequency of 10 Mc/sec. The values extrapolated to 0°K areC11=29.94±0.06,C33=34.22±0.12,C44=16.62±0.05,C12=2.76±0.08,C13=1.1±0.5 in units of 1011dyne/cm2. Voigt averaging and Reuss averaging of the single crystal elastic constants give excellent agreement because of the small magnitude of the nondiagonal elements,C12andC13. The averaged values compare favorably with previous data from polycrystalline beryllium.

ISSN:0021-8979    

DOI:10.1063/1.1735427

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

An experimental study is made of the photoelectric emission from tantalum as it depends directly on accelerating electric field. Observations cover a range of fields from 0 to 90 kv/cm and illumination wavelengths from 248 to 300 m&mgr;. The results are in agreement with the Fowler photoelectric theory modified by a Schottky lowering of the surface barrier. No evidence is found for a periodic deviation from this regular behavior such as exists in its thermionic counterpart, but experimental conditions may have been inadequate for the observation of such a deviation. A new method of threshold measurement at high fields is described and applied to drawn tantalum filaments of circular cross section. The resulting value is 4.16 ev for freshly flashed specimens and it is suggested that this is slightly greater than the lowest work function present in the surface. A Fowler determination in the same field range yields 4.13 ev. The influence of nonuniformity of the surface work function on the field dependence of photoemission and on threshold measurements is discussed.

ISSN:0021-8979    

DOI:10.1063/1.1735381

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

The factors which govern the occurrence and stability of etch hillocks and pits have been examined. Batterman's original analysis has been reconsidered and extended to account for all the crystallographic facets of etch hillocks and pits produced by a dilute hydrogen peroxide‐hydrofluoric acid etchant on germanium surfaces. The treatment should be valid for other etchants and materials but suitable data are not available.

ISSN:0021-8979    

DOI:10.1063/1.1735382

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

Whiskers of hexagonal SiC have been prepared in a graphite tube furnace. They are grown by sublimation of SiC in hydrogen, depositing at temperatures about 2000°C as acicular crystals of hexagonal section, with [0001] along the whisker length. The {11¯00} faces have been examined using optical interference techniques, and are found to exhibit a twist. The Eshelby formula for twist caused by a screw dislocation has been used to estimate the strength of the associated Burgers vector. It is found that, within the experimental error, the estimated Burgers vector is equal to, or is an integral multiple of the unit cell of the SiC polytype 4H. It is thus concluded that these twisted whiskers grow by means of a screw dislocation of integral strength parallel to the axis, and that they are of polytype 4H.

ISSN:0021-8979    

DOI:10.1063/1.1735383

出版商:AIP    

年代:1960

数据来源: AIP