摘要:

An annular semiconductor diode detector was used in a Cambridge Stereoscan electron microscope to resolve beam‐orientation‐dependent backscattered electron images not only as bands but also as extremely complicated defect and excess line patterns with angular resolution ≤ 5 × 10−4rad. The resultant patterns are similar in appearance to transmission and reflection Kikuchi electron diffraction patterns.

ISSN:0003-6951    

DOI:10.1063/1.1652657

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

The frequency dependence of microwave elastic losses for longitudinal waves along thecaxis of a &bgr;‐rhombohedral boron crystal have been measured from 0.5 to 1.8 GHz at 4 and 300°K. At 1 and 1.5 GHz, the temperature dependence of these losses has been determined from 4 to 300°K. At 300°K, the attenuation due to interaction with thermal phonons is found to vary quadratically with frequency, in accord with theory, and to have a value of 0.1 dB/cm at 1 GHz. The sound velocity of the longitudinal wave along thecaxis is found to be 1.4 × 106cm/sec.

ISSN:0003-6951    

DOI:10.1063/1.1652658

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Various organic scintillators have been placed in rf fields. The light emitted during the first few nanoseconds of the fluorescence may be greatly reduced if the frequency of the rf is about 340 MHz. rf stimulation shapes fluorescence pulses and this may be used to eliminate noise and enhance neutron‐&ggr; separation in a scintillation detector.

ISSN:0003-6951    

DOI:10.1063/1.1652659

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Existing nominal electric fields in unirradiated and electron‐bombarded silicon dioxide layers of SOS‐sandwich structures were determined by means of optical probing. The method of investigation is based on the quadratic electro‐optical Kerr effect and employs a suitable optical arrangement in connection with a 0.6328‐&mgr; helium‐neon laser.

ISSN:0003-6951    

DOI:10.1063/1.1652660

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Laser‐induced generation of second‐ and third‐harmonic radiation is studied in cholesteryl nonanoate and in other cholesteric and nematic liquid crystals. No second harmonic is observed in any of the liquid‐crystal mesomorphic phases, indicating their ordered molecular arrangements to be centrosymmetric. Large changes in third‐harmonic intensity occur at several phase transitions, and their possible origins are considered.

ISSN:0003-6951    

DOI:10.1063/1.1652661

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

A decrease in resistivity with increasing magnetic field has been found in high‐purityn‐type germanium subjected to crossedEandBfields at 4.2°K. The effect is due to an increase in carrier density with increasingBcaused by impact ionization of previously un‐ionized donors, and is associated with the presence of the Hall electric field. It is accompanied by bulk oscillations in the megacycle range.

ISSN:0003-6951    

DOI:10.1063/1.1652662

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Chromium‐doped semi‐insulating gallium arsenide has been successfully dopedn‐type by ion implantation of silicon. Annealing studies are presented which show that at annealing temperatures in excess of 600°C, conductivity and Hall mobility rise to values comparable to those expected for heavily doped gallium arsenide.

ISSN:0003-6951    

DOI:10.1063/1.1652663

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Investigations of the conditions under which the donors, P, As, and Sb, are incorporated into Si by by ion implantation (260–300 keV) in an electrically active form are reported. Above a critical dose, room‐temperature implantations followed by a 600°C post anneal are substantially more effective than implantations at 600°C.

ISSN:0003-6951    

DOI:10.1063/1.1652664

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

A ``displaced linear branch'' has been observed in the volt‐ampere characteristics of square (1 × 1‐mm) Sn&sngbnd;Ox&sngbnd;Sn and Pb&sngbnd;Ox&sngbnd;Pb Josephson junctions. The slope of the linear branch is independent of magnetic field and independent of temperature below 2.2°K. It is suggested that this effect can be attributed to internal flux motion.

ISSN:0003-6951    

DOI:10.1063/1.1652665

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

The spatial variation of the fluorescence intensity after multiphoton absorption in dye solutions is explained in terms of standing light waves. The mirror reflectivity affects the contrast ratios. Furthermore, the influence of the mirror on the process of fluorescence emission is considered.

ISSN:0003-6951    

DOI:10.1063/1.1652666

出版商:AIP    

年代:1969

数据来源: AIP