摘要:

With increasing temperature the sequence of phase transitions orthorhombic→tetragonal→cubic is observed for a PLZT ceramic of 7.5/64/36 composition. At 20 °C the inverse sequence is seen as a function of poling field. The compositional dependence of the transition temperatures is reported over a limited range.

ISSN:0003-6951    

DOI:10.1063/1.88025

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Storage experiments of Bleustein‐Gulyaev surface acoustic wave in CdS, carried out at room temperature, are described. Storage time varies from 40 &mgr;sec to 2.5 msec. A linear relationship between the stored pattern decay time and the sample resistivity has been experimentally found. The storage mechanism involves deep bulk traps.

ISSN:0003-6951    

DOI:10.1063/1.88026

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

It is shown that the temperature as deduced by the filter method is unaffected by departures from the corona ionization equilibrium for a low‐temperature carbohydride laser‐produced plasma.

ISSN:0003-6951    

DOI:10.1063/1.88027

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

The centering of relativistic superpinched beams from large aspect ratio diodes (r/d≫1) onto small targets for studies of superpinches relies on a centering force, which is normally so weak that small diode asymmetries will cause the beam to pinch off axis. A new technique is described herein that increases the magnetic centering force by approximately a factor of 103through control of the return current flow pattern on the anode surface. Preliminary experiments conducted on the Nereus accelerator (Vg=100 kV,Ip=50 kA, and &tgr;=50 ns) have demonstrated that the superpinch can be reproducibly centered within 0.025 cm of the axis of a 2.54‐cm‐diam flat cathode.

ISSN:0003-6951    

DOI:10.1063/1.88028

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Experiments have been carried out using a reflex triode‐type pulsed ion accelerator at voltages up to 1.8 MeV. Large reductions in the breakdown electron current drawn by the system resulted from the electron reflexing. Diode closure was the major problem and was strongly affected by the choice of anode materials. The best results were obtained with thin aluminum foil anodes. Over a total accelerating pulse of 130 nsec peak aluminum currents in excess of 5 kA were extracted with a peak energy of Al++of 3 MeV.

ISSN:0003-6951    

DOI:10.1063/1.88029

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

The spectrum of spin polarization and yield of photoelectrons from negative electron affinity GaAs were measured. The results show that GaAs is an excellent source of polarized electrons withP∼50&percent;, high current, small energy spread, and high brightness.

ISSN:0003-6951    

DOI:10.1063/1.88030

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Radiation patterns of 10.6‐&mgr; infrared antennas have been obtained experimentally and interpreted by means of a simple theory. It is found that the effective antenna length is equal to the length of theetchedportionof the sharpened cat‐whisker antenna. This effective antenna length appears to be caused by decoupling of the electromagnetic field across a shape discontinuity of the antenna wire. The results suggest a simple means for defining shape and size of infrared antenna structures.

ISSN:0003-6951    

DOI:10.1063/1.88031

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Measurements are reported of the total charge and its mean position in liquid‐charged FEP electrets. A new nondestructive technique has been used. The large difference in decay rates of positive and negative liquid‐charged electrets is accompanied by quite different behavior of the deposited charge as it migrates through the electret. The total volume charge density present in untreated FEP has been measured: it typically amounts to 0.1–0.6 C m−3for 25‐&mgr;‐thick material.

ISSN:0003-6951    

DOI:10.1063/1.88032

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Ranges of Xe, Cs, Eu, Au, and Tl in polycrystalline Al and anodic Al2O3at 75–100 keV are reported. Ranges in Al2O3are found to be about 30&percent; higher than predicted by the LSS theory for allZ1. The shapes of the depth distributions are in excellent agreement with theoretical calculations. In Al, considerable deviations from theory for the most probable ranges and for the shapes of the distributions are found. These deviations are attributed to crystalline effects.

ISSN:0003-6951    

DOI:10.1063/1.88033

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

The temperature dependence of laser‐induced transverse voltages in Pt and Pd films has been investigated in the range ∼25–300 °K. When the data are normalized to a constant average film temperature gradient, a close similarity is found between the normalized values and bulk thermopower data throughout the temperature range. These results suggest a possible model requiring only scalar thermopower coefficients.

ISSN:0003-6951    

DOI:10.1063/1.88034

出版商:AIP    

年代:1975

数据来源: AIP