摘要:

A generalized expression has been derived for the effective secondary electron emission coefficient &ggr;, in Penning mixtures which incorporates the effect of both the majority and minority ions. Specific calculations for ac panels having an Ne+0.1%Ar mixture show that even a relatively small value of &ggr;Arnot only significantly lowers the breakdown voltages, but also moves the voltage minimum to higherp0dvalues and makes the right‐hand side of the Paschen curve less steep. This sensitivity of the effective coefficient &ggr; on &ggr;Aris sufficient to explain the critical dependence of the shape of the measured breakdown voltage curves in ac panels on minor changes in the surface properties of the deposited insulator surfaces.

ISSN:0021-8979    

DOI:10.1063/1.322475

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

The use of titanium‐doped quartz as the laser tube in an iodine photodissociation laser eliminates the deposition of carbon on the tube wall. Shock waves arising from absorption of flashlamp light by these carbon deposits are also eliminated.

ISSN:0021-8979    

DOI:10.1063/1.322476

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

We have observed electrical breakdown and current‐controlled negative differential resistance (NDR) in an epitaxialn‐GaAs film at room temperature by using a field effect structure. The breakdown is attributed to the impact excitation of electrons trapped in 0.9‐eV centers of concentration ∼1016cm−3. The origin of NDR is explained by the theory which was originally developed for the breakdown phenomenon in Ge at low temperatures.

ISSN:0021-8979    

DOI:10.1063/1.322477

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

Thermally stimulated charge decay is applied to determine the energy distribution of interface states at the insulator‐semiconductor interface. TSCD is measured in open circuit and the surface potential of the semiconductor can be easily obtained. A method to estimate the energy distribution from TSCD is explained using experimental results in Al‐SiO2‐Si MIS structure.

ISSN:0021-8979    

DOI:10.1063/1.322478

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

Results of an earlier thermal‐expansion study have been revised using values for the specimen temperature obtained by an improved method.

ISSN:0021-8979    

DOI:10.1063/1.322479

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

A simple method of experimentally determining the demagnetization factors of nonellipsoidal samples using the convolution of contradirected magnetoelastic Rayleigh waves is described. The experimental results are in reasonable agreement with first‐order theoretical expressions for the demagnetizing factors.

ISSN:0021-8979    

DOI:10.1063/1.322480

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

In a recent paper allnatt and Sime described some high‐temperature electrical‐conductivity experiments on sodium chloride and potassium chloride in which the activation enthalpy for the conductivity was 110−210 eV and 440 eV, respectively. In this paper we suggest that the rapid rise in conductivity is due to the enhanced diffusion of charged defects along thermally formed dislocations. We present a formula for the conductivity along thermal dislocations and using it we calculate entropies of 1150k‐2190kfor NaCl and 4750kfor KCl. Together with the high enthalpies these entropies are consistent with the Gibb’s function for the formation of thermal dislocations approaching zero at the melting point, implying that on melting the crystal is highly dislocated.

ISSN:0021-8979    

DOI:10.1063/1.322481

出版商:AIP    

年代:1976

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.322483

出版商:AIP    

年代:1976

数据来源: AIP