摘要:

We have measured with nanosecond laser pulses the spectral broadening of light emitted from a filament under controlled input conditions. Our results are in semiquantitative agreement with predictions from the moving‐focus model.

ISSN:0003-6951    

DOI:10.1063/1.1654327

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

We have observed splittings between the &sgr;+and &sgr;−groups of components of optical lines emitted by fast beams of Ar+and O+[v/c= (3.2−4.2) × 10−3] in a magnetic field of 13 800 G. In order to observe these separations, which were of the order of 0.2–0.3 Å, it was necessary to reduce the recorded widths of spectral lines by refocusing the spectrometer and by exciting the beam in a gas target.

ISSN:0003-6951    

DOI:10.1063/1.1654328

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Gas breakdown, ionization of a gas by laser radiation, sets an upper limit on the operating pressure of pulsed CO2lasers. The breakdown threshold decreases with increasing pressure, whereas the saturation energy of the laser increases with pressure. These two competing effects lead to the prediction of a maximum operating pressure above which the energy stored in the laser cannot be extracted without initiating gas breakdown. Gas‐breakdown‐threshold measurements have been made in typical laser mixtures, and breakdown has also been observed inside the laser cavity of an atmospheric‐pressure CO2laser. Based on these measurements and previously reported saturation measurements, the upper limit for efficient use of CO2lasers is predicted to be in the range of 2–4 atm.

ISSN:0003-6951    

DOI:10.1063/1.1654329

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

The potential has been probed onn‐type InSb bar samples at nanosecond time scales, both with and without an applied magnetic field. In a transverse magnetic field, nucleation of a traveling domain occurs at the side of the cathode where the electric field is high due to Hall field shorting. The results explain the strong reduction of Gunn effect threshold in a magnetic field.

ISSN:0003-6951    

DOI:10.1063/1.1654330

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Vacuum‐deposited films now replace the familiar ``rubbing'' process in substrate preparation for liquid‐crystal cells. Films deposited at an angle provide an oriented surface for alignment of nematic liquid crystals far better than the well‐known ``rubbed'' plate. The oblique deposit causes a film growth in a preferred direction, which results in a ``sympathetic alignment'' of the nematic liquid crystals when applied.

ISSN:0003-6951    

DOI:10.1063/1.1654331

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A disruption in the flow of an intense annular relativistic electron beam occurred when a sudden change in the radius of the drift tube walls was introduced. Experimental results showed that the electron beam (which was immersed in a homogeneous magnetic field) was under the influence of a strong nonadiabatic force which caused considerable changes in beam characteristics, such as spatial distribution and electron transverse energy.

ISSN:0003-6951    

DOI:10.1063/1.1654332

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

The theoretical description of transistors has been impeded by the lack of knowledge of thep‐type impurity distributions. A method is described which accurately gives concentration profiles of the boronp‐type regions in transistors. The technique has been used to establish that the base regions in the fastest bipolar transistors are markedly different than usually assumed.

ISSN:0003-6951    

DOI:10.1063/1.1654333

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

An investigation of the properties of Mo&sngbnd;Re thin films has been undertaken. Superconducting transition temperatures of up to ∼15°K have been observed in films which have an approximate composition of Mo0.7Re0.3. This increase inTcof 2–3°K over the corresponding bulk values is attributed to the formation of a metastable A‐15 phase in the sputtered films of this composition.

ISSN:0003-6951    

DOI:10.1063/1.1654334

出版商:AIP    

年代:1972

数据来源: AIP