摘要:

Switching and oscillation were found in SnO2‐VOx‐PdO ceramics. This switching does not appear above 60°C. However, under 40°C, it comprises two switching actions and depends upon the ambient temperature. The oscillation is irregular and the amplitude is as great as 30−40 V at room temperature.

ISSN:0003-6951    

DOI:10.1063/1.89725

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Two‐port SAW resonators have been made on ST‐cut quartz to operate at 310 MHz with unloadedQvalues in vacuum in excess of 32 000 (the limit onQimposed by intrinsic material loss at this frequency is approximately 33 000). Design principles and fabrication techniques employed in the realization of these devices are described.

ISSN:0003-6951    

DOI:10.1063/1.89726

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

A quantitative comparison of anisotropic theory with experiments on SiO2and LiNbO3shows the strong effects of wave surface anisotropy on SAW resonator transverse modes. Simple approximate formulas for the frequency splittings of the resonant modes are given for both the waveguided case and the unguided case where ’’free‐space’’ modes are prevalent.

ISSN:0003-6951    

DOI:10.1063/1.89727

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

The dynamics of electron avalanche breakdown induced by picosecond laser pulses were observed directly with an ultrafast streak camera. The ionization rate for fused quartz exposed to a 25‐psec 532‐nm pulse which produced a damaging breakdown is ⩾4.5×1012sec−1.

ISSN:0003-6951    

DOI:10.1063/1.89728

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Measurement of the voltages of isolated targets irradiated with 50‐psec laser pulses show kilovolt target potentials existing for many nanoseconds. The amplitude of the voltage exceeds what is normally expected for a plasma pressure gradient by roughly an order of magnitude. The voltage amplitude and temporal characteristics are found to be dependent on the vacuum chamber dimensions. A simple one‐dimensional plasma model explains the voltage characteristics through the existence of space‐charge separation effects and leads to a measurement of the plasma temperature.

ISSN:0003-6951    

DOI:10.1063/1.89729

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

InP has been doped by implantation with several different ions to yield layers of bothn‐ andp‐type conductivity. Se+and Si+were found to be efficientn‐type dopants with activations in excess of 75% for moderate doses (1×1014cm−2at 400 keV). At doses of 1×1015cm−2, sheet resistivities as low as 15 &OHgr;/&laplac; were obtained. Cd+, Mg+, and Be+were all acceptors, with Mg+yielding a sheet hole concentration as high as 5×1013cm−2for a dose of 1×1014cm−2at 150 keV. Reproducible annealing of implanted samples at temperatures up to 750 °C was accomplished with a pyrolytic phosphosilicate glass (PSG) encapsulation. Implants of Kr+indicate that residual implantation damage isntype.

ISSN:0003-6951    

DOI:10.1063/1.89730

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Amorphous Pd80Si20was irradiated with fast neutrons (≳1 MeV) to a fluence of 5×1020neutrons/cm2. X‐ray scattering intensities were measured before and after the irradiation with monochromatic Cu‐K&agr;1rays. Scattered intensities fors≳0.4 A˚−1(s=2 sin&Vthgr;/&lgr;) proved unaffected, while intensities were found remarkably enhanced fors<0.4 A˚−1after the irradiation, i.e., in the small‐angle region and the leading edge of the first halo. The results are discussed in relation to the structural anomalies in amorphous solids.

ISSN:0003-6951    

DOI:10.1063/1.89731

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Composite films of Ni particles embedded in an Al2O3matrix have been produced by controlled coevaporation. The optical properties of the Ni/Al2O3composites measured over the range of the solar spectrum are in good accord with the predictions of Maxwell‐Garnett theory provided the Ni volume fraction is ≲0.2. The composite films have excellent spectral selectivity for the absorption of solar radiation, with a solar absorptivity of 0.94 obtained for a film produced with a composition gradient. Low‐temperature emissivities of ∼0.1 have been obtained with composite films evaporated on highly reflecting metal substrates.

ISSN:0003-6951    

DOI:10.1063/1.89732

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

A new interferometric alignment technique has been developed that is suitable for aligning x‐ray lithography masks or photomasks relative to a substrate. A superposition precision of 200 A˚ has been demonstrated and in principle ∼100 A˚ should be possible. The superposition of matching grating type alignment marks on facing plates is determined from the intensities of beams multiply diffracted from the matching alignment marks. The principle of the interferometric alignment technique is described.

ISSN:0003-6951    

DOI:10.1063/1.89719

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Direct nuclear pumping of the 1.45‐&mgr; line in neutral carbon has been achieved using the10B(n,&agr;)7Li reaction. Lasing was observed in mixtures of both He‐CO and He‐CO2. The laser has the lowest neutron flux threshold to date, ∼4×1014n/cm2 sec, and a 20‐msec lasing time. Lasing occurred at pressures from 20–800 Torr He with partial pressures of CO and CO2from ∼1–21 mTorr. A delay, increasing to ∼5 msec for lower total pressures, was observed between the peak of the neutron pulse and the peak of the laser signal for mTorr partial pressures of CO2, and for mTorr partial pressures of N2‐CO mixtures.

ISSN:0003-6951    

DOI:10.1063/1.89720

出版商:AIP    

年代:1977

数据来源: AIP