摘要:

F‐type centers have been introduced in to single crystals of &agr;‐Al2O3by heating them at 2000 °C in a graphite crucible under strongly reducing conditions. This treatment produces results similar to additive coloration in that anion vacancies charge compensated by electrons are introduced as demonstrated by the presence of a 6.1‐eV optical absorption band after heating. Although the same band can be created by high‐energy‐particle bombardment; by contrast those resulting from this additive coloration procedure are very stable against thermal annealing. Annealing above 1400 °C in air is necessary to produce a decrease in the 6.1‐eV‐band amplitude. The 6.1‐eV band has been related to theFcenter in our previous study. This study further substantiates this model.

ISSN:0003-6951    

DOI:10.1063/1.90362

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A new electrothermo‐optic effect is described in a certain smectic liquid crystal with a pleochroic dye added. The thermally induced optical storage state in this mode consists of a mosaic texture. It does not show light scattering but has excellent coloration. The erasure of this state is made by the use of a field‐assisted thermal process.

ISSN:0003-6951    

DOI:10.1063/1.90363

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Utilization of a preacceleration potential to accelerate ions before they reach the emission aperture results in a substantial increase in the transmission efficiency. For an intense modified duoPIGatron focused multibeamlet (1799 apertures) 22‐cm‐diam ion source, the total transmission efficiency for beam power through an aperture 20×25 cm located 4.10 m downstream increased 30%. This result is in agreement with a previous solution to the appropriate two‐dimensional Poisson‐Vlasov equation for ions extracted from a plasma.

ISSN:0003-6951    

DOI:10.1063/1.90364

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

It is shown that theV‐icharacteristic of discharges in flashlamps operating in the prepulsed mode at high current densities follows the relationshipV=K0i0.85. This result is interpreted in terms of the Sagdeev‐Galeev anomalous resistivity due to current‐driven ion‐acoustic turbulence.

ISSN:0003-6951    

DOI:10.1063/1.90340

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Small 5‐mm‐diam high‐density 3×1017cm−3&Vthgr;‐pinch plasma columns 1‐m long have been heated by intense long‐wavelength laser radiation (10 &mgr;) along their entire length. Refractive beam trapping has been achieved when laser heating begins during or before the &Vthgr;‐pinch implosion. Plasma temperatures have been increased from under 2 eV to maximum values of between 30 and 90 eV, in agreement with a MHD laser heating code.

ISSN:0003-6951    

DOI:10.1063/1.90365

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The Brillouin theory is generalized to an infinitely long vacuum transmission line of arbitrary cross section. It is shown that the equation describing the system can be reduced to a simple Laplace equation. A general expression for the total current is shown to be inversely proportional to the characteristic impedance. An analytical example is presented in the text.

ISSN:0003-6951    

DOI:10.1063/1.90366

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The behavior during annealing of heavily doped silicon layers obtained by a high‐current‐density ion implantation, realized by discharge in BF3atmosphere, is investigated. The annealing is performed by a laser pulse and the surface layers are studied by Rutherford backscattering, SIMS, and conductivity measurements. Comparisons with thermal annealing show the advantage of using laser pulses to restore the original crystallinity.

ISSN:0003-6951    

DOI:10.1063/1.90367

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A novel diffusion ’’marker’’ has been used in the backscattering study of the formation of Mo and W silicide films. Because of their closely similar crystallographic and chemical characteristics, Mo and W may be regarded as equivalent atoms in a diffusion process. Hence, in the formation of WSi2and MoSi2by interaction of a bilayer film of W+Mo with substrate Si, the interface between the W and Mo (observable by backscattering) becomes a ’’marker’’ to permit identification of the moving species (Si atT<1000 °C).

ISSN:0003-6951    

DOI:10.1063/1.90341

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Refractive‐index dispersion of magnetic garnet films of composition (YSmLuCa)3(GeFe)5O12is reported in a wavelength range of 0.55–1.5 &mgr;. The dispersion was calculated from the film’s optical interference data and thickness value which was accurately determined by the technique of thin‐film optical waveguide measurement. The calculated index values at the interference fringe locations were fitted to a two‐term Sellmeier formulation. The accuracy was estimated to be better than 0.3%.

ISSN:0003-6951    

DOI:10.1063/1.90342

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The excitation spectrum of thallium‐doped silicon has been measured in crystals doped to a level of 5×1016Tl/cm3. The spectrum is characteristic of an effective‐mass‐like acceptor with an optical ionization energy of 0.246 meV. The peak optical cross section was estimated to be 2.6×10−17cm2.

ISSN:0003-6951    

DOI:10.1063/1.90343

出版商:AIP    

年代:1978

数据来源: AIP