摘要:

In Si junction diodes it is possible to achieve a short recombination time together with a large storage time at room temperature by deliberately introducing impurities with asymmetric trapping levels, such as Pt, into the region of the junction. It is shown that this technique can be used in surface‐acoustic‐wave devices to increase the bandwidth by reducing the writing time on a junction memory to 5×10−9sec while the storage time remains above 0.2 sec.

ISSN:0003-6951    

DOI:10.1063/1.90485

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Angular scattering from surface cracks has been used for determining the length of a surface crack. This technique assumes the physical availability of space to carry out an angular scattering experiment, and makes no estimation of the depth of the crack. In this work, we report a new technique where the scattering from surface cracks is made versus frequency, at one angle of incidence only. Length and depth resonances of the crack are observed and used to estimate the crack geometry. We made our measurements on EDM notches in steel. The geometry of the crack has been predicted with an accuracy of 10–20%.

ISSN:0003-6951    

DOI:10.1063/1.90486

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A new design of SAW filters having an inclined and tapered three transducer (ITTT) configuration is effective for the suppression of the triple‐transit (TTE) caused by the regeneration of an surface acoustic wave. In the ITTT configuration, the electrode fingers of the transducers are not parallel with each other but are tapered, and further, each of the outer output transducers is inclined with respect to the central input transducer. A video i.f. filter for TV having the ITTT configuration was fabricated using a piezoelectric ceramic substrate. The filter exhibited an insertion loss of 9.6 dB and ripple in the group delay of less than 50 nsec.

ISSN:0003-6951    

DOI:10.1063/1.90463

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A new method of measuring the low tilt bias angles of liquid‐crystal displays is proposed. It is based on the threshold characteristics of magnetocapacitance, which vary according to the relative direction of the magnetic field and the directors. The tilt bias angle is determined completely by geometrical configurations and without any fitting procedure. The method ensures accuracy up to 0.1° in the present example. Threshold field variations due to sample rotation in the magnetic field are calculated from the theoretical magnetocapacitive curves, and experimental results are in good agreement with them.

ISSN:0003-6951    

DOI:10.1063/1.90487

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The electrochromic cermet Au‐WO3is composed of grains of Au, approximately 20–120 A˚ in diameter, embedded in a matrix of amorphous WO3. The optical properties of the cermet, in its red electrochemically colored state, are different from the optical properties of its two components. WO3becomes highly electrically conducting when colored, but colored WO3in the presence of Au grains remains an insulator. A study of the optical and electrical properties of the cermet as a function of gold concentration is presented.

ISSN:0003-6951    

DOI:10.1063/1.90488

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

We show that coloration and bleaching times of anodic iridium oxide films (AIROF’s) are insensitive to pH. Similar kinetics are observed for aqueous solutions of 0.5MH2SO4, 4MLiNO3, or 0.5MNaOH, and for a solution of 3MLiNO3in methanol. This suggests that long‐term stability may be achieved without degrading response time. It also shows that the mechanism for electrochromism in AIROF’s is fundamentally different from the ion‐electron double‐injection operative in the tungsten bronzes and recently proposed for AIROF’s. In fact it appears to be sufficient that current flow across the AIROF solution interface be carried solely by electrons. We also show that AIROF’s have markedly improved bleaching kinetics, reproducibility, and stability following heat treatment.

ISSN:0003-6951    

DOI:10.1063/1.90489

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The rate of dissociative attachment of electrons to F2in mixtures with N2and Ar has been measured over the electron mean energy range 0.9–4 eV. The results show that the rate is about 7×10−9cm3/s at a mean energy of 1 eV, and decreases with increasing electron mean energy as (mean energy)−3/2.

ISSN:0003-6951    

DOI:10.1063/1.90490

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The cross section for Compton scattering can be appreciably enhanced if energy is conserved in the initial to intermediate state transition. This resonance condition cannot be satisfied for a free particle, but it can be met if the particle is in a static electric or magnetic field. In this paper an analysis is presented for light scattering from relativistic particles in an electrostatic potential. Planar channeled positrons are used as the example. It is possible to achieve a large frequency upshift from the incident to the scattered radiation, with a cross section that is many orders of magnitude larger than the usual Compton cross section.

ISSN:0003-6951    

DOI:10.1063/1.90491

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Rates, &agr;, for the recombination of Kr+and Kr+2with F−in various buffer rare gases (He, Ne, Ar, Kr, Xe) at 300 K are calculated for a wide range of gas pressures. For pressures 1–5 atm, the population of KrF* via recombination is greatest for Ne and Ar as third bodies, yielding &agr;∼3×10−6cm3 sec−1, while for pressures ≳10 atm, He is to be preferred as a buffer gas.

ISSN:0003-6951    

DOI:10.1063/1.90464

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

ISS, SIMS (recoil target ions), and ion‐produced photon emission (IPP) from surfaces subject to low‐energy ion bombardment have been compared by simultaneous measurement of the effect of reactive gas adsorption on each signal. A direct correlation between the three signal strengths has been established. Cross sections for desorption of CO from Ni due to low‐energy ion bombardment have been measured independently and simultaneously by two of the three methods.

ISSN:0003-6951    

DOI:10.1063/1.90465

出版商:AIP    

年代:1978

数据来源: AIP