摘要:

The images of a high‐frequency bipolar transistor obtained with an acoustic microscope are compared with those of a differential interference optical microscope and a scanning electron microscope in order to illustrate that the acoustic microscope can be used in a reflection‐type mode to obtain quality pictures of a surface containing integrated circuits. The frequency of the acoustic beam is 600 MHz and the resolution is near 2 &mgr;.

ISSN:0003-6951    

DOI:10.1063/1.1655459

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Thin wafers of LiTaO3prepared from fully poled boules by mechanical cutting and polishing techniques have been found to contain defects at high concentrations (up to 107/cm2). Examination of these wafers by optical and electron microscope techniques indicates that the defects are cylindrical domains 1–3 &mgr;m in diameter, within which the ferroelectric axis is inverted relative to the surrounding material. These inverted domains appear to have nucleated at screw dislocations,b∥ <0001>, which are observed near the axis of each domain. The results have implications for many applications of LiTaO3, because such multidomain configurations may contribute to undesirable optical scattering, Barkhausen noise, or degraded pyroelectric response. It is suggested also that the permanent optical damage generated in LiTaO3by intense laser radiation may arise in part by the nucleation of similar inverted domains at dislocations generated through the action of large thermal stresses.

ISSN:0003-6951    

DOI:10.1063/1.1655460

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A wraparound acoustic surface wave (ASW) delay line incorporating a periodical &Dgr;&ngr;/&ngr; lens guiding structure and a monolithic InSb amplifier is described. Normal mode computation accounts for parabolic anisotropy. Experimental results on a 120‐MHz recirculating LiNbO3delay line are reported.

ISSN:0003-6951    

DOI:10.1063/1.1655461

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A hollow relativistic electron beam, drifting in vacuum, can be made to implode radially when a grounded conductor is placed on the beam axis. The collapse is the result of the change in the direction of the electric field relative to that of a freely propagating beam. The entire energy content of the collapsed beam is dissipated in the conductor.

ISSN:0003-6951    

DOI:10.1063/1.1655462

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Deposition of an Sl&sngbnd; [Ag&sngbnd;O&sngbnd;Cs] type photocathode onto a diffraction grating substrate has been shown to produce a photoemitter which provides resonant coupling to surface waves and associated significant enhancement in quantum efficiency at preselected frequencies for specified light angle of incidence.

ISSN:0003-6951    

DOI:10.1063/1.1655463

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

An electrically controllable diffraction mode in liquid crystals is described. The variable grating is a stable single layer of small uniform birefringent spherulitic domains imbedded in a homeotropic matrix. The size of the domains is changed by small dc or ac voltages.

ISSN:0003-6951    

DOI:10.1063/1.1655464

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Electron irradiations were performed on six nines purity gold in the 3‐MV electron microscope at Toulouse. Partially ordered vacancy tetrahedra were observed in all of the sample while interstitial loops were formed in its thick parts. Investigation of the nature and cause of the ordering are reported.

ISSN:0003-6951    

DOI:10.1063/1.1655465

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

It is demonstrated that the electronically focused acoustic imaging device is equivalent to a diode convolver where the sound image is formed by using the convolver to perform a Fresnel transform of the sound field at the receiving array.

ISSN:0003-6951    

DOI:10.1063/1.1655466

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

An ultrafast x‐ray‐sensitive streak camera is described. Time resolution is ≈50 psec. A streak record of the x rays from a laser‐produced iron plasma is included.

ISSN:0003-6951    

DOI:10.1063/1.1655467

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The distribution function of relaxation times for the &agr; dispersion in polycarbonate has been calculated from measurements of thermally stimulated discharge currents. This function can be adequately described by the empirical expression of Havriliak and Negami, first derived from the complex plane analysis of ac dielectric data. The values of the distribution parameters obtained from the two types of measurements are in excellent agreement.

ISSN:0003-6951    

DOI:10.1063/1.1655468

出版商:AIP    

年代:1974

数据来源: AIP