ISSN:0003-6951    

DOI:10.1063/1.1754689

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

The Brillouin scattering spectra of crystalline quartz, fused quartz and Pyrex glass have been observed. The crystalline quartz spectrum contains three doublets corresponding to one longitudinal and two transverse acoustic modes, whereas the spectra of used quartz and Pyrex glass have one longitudinal and one transverse component each, as is expected for isotropic solids. From the lack of observable broadening of any of the Brillouin components, it is concluded that the room temperature attenuation coefficient &agr; of both longitudinal and transverse phonons at 10 to 20 Gc is less than 103cm−1.

ISSN:0003-6951    

DOI:10.1063/1.1754690

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

Mn K x rays from55Fe were diffracted with detectable intensity by NaCl and LiF powder. A special diffractometer incorporating a 100‐mc55Fe linear source (1.5 mm × 10 mm) was used. Theoretical diffraction efficiency is about 10−5(on the NaCl 200 plane). Diffractometer geometry provided 10−1to 101photons per min at the detector. This order of intensity was observed with a proportional counter, linear pulse amplifiers, and a multichannel analyzer. The three most intense beams of LiF (&thgr; = 20° to 55°) were clearly demonstrated.

ISSN:0003-6951    

DOI:10.1063/1.1754691

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

A Faraday unipolar inductor using a solid cylinder of a nonideal type II superconductor (unannealed Nb) constitutes a zero internal impedance generator capable of supplying appreciable electrical power and permits continuous study of the behavior of the average internal magnetic field vs the applied field. The various contributions to the observed emf are discussed in terms of the relativistic interpretation of Faraday unipolar induction.

ISSN:0003-6951    

DOI:10.1063/1.1754692

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

A technique is described for the measurement of plasma density. Multiple beam interferometry gives simultaneous time and position information on the state of the laser‐induced plasma. Experiments using a single interferometric probe at various distances from the target surface along the incident laser axis indicates that the leading edge of the blowoff absorbs a portion of the incident energy and hence additional fringe shifts are observed.

ISSN:0003-6951    

DOI:10.1063/1.1754693

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

This Letter reports the measurement of an upper bound of 0.8 nsec for the time of transition of Sn&sngbnd;SnOx&sngbnd;Sn Josephson junctions from the pair tunneling (V= 0) to the single‐particle tunneling state (V= 2&Dgr;: 1mV at 1.7°K). The threshold is extremely sharp. There is no observed delay in the transition after the threshold is exceeded, and there is no change in the observed risetime of the signal with changes in driving current amplitude or risetime. The magnetic field behavior of these junctions is the same as that observed in the dc case. The combination of high speed, sharp threshold, and strong magnetic field dependence are desirable properties for logic elements.

ISSN:0003-6951    

DOI:10.1063/1.1754694

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

Linear and nonlinear optical investigations of LiNbO3and LiTaO3from room temperature to temperatures above their ferroelectric phase transitions are described. The measurements include studies of second harmonic generation with an Nd laser (1.06 &mgr;) and determinations of the refractive indices as well as the birefringence at 0.6328 &mgr;. All the optical data exhibit distinct changes at the Curie temperatures,Tc= 1195°C ± 15°C for LiNbO3, andTc= 610°C ± 10°C for LiTaO3. In each case the phase change has the characteristics of a second‐order ferroelectric transition. The uniaxial paraelectric phases are concluded to be centrosymmetric — probably space groupR3¯c.

ISSN:0003-6951    

DOI:10.1063/1.1754695

出版商:AIP    

年代:1966

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.1754696

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

High repetition rate (30–60 kc/sec)Q‐switching in a CO2laser at 10.6&mgr; is reported. A moving mirror technique using steady mirror velocities between 16 and 30 cm/sec produces one pulse of the strongest line (P(20)) per half wavelength of travel. The usable pulsing rate is determined by, and is a measure of, the lower laser level lifetime (∼30 &mgr;sec). In a 1‐W CW laser, peak powers ≈ 30 W with pulse lengths ≈ 1 &mgr;sec and average power ≈ CW power were obtained. This and related competition and hysteresis effects result from strong coupling between the lines of the vibrational‐rotational spectrum due to thermalizing molecular collisions.

ISSN:0003-6951    

DOI:10.1063/1.1754697

出版商:AIP    

年代:1966

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.1754698

出版商:AIP    

年代:1966

数据来源: AIP