摘要:

A temperature-independent field acceleration parameter &ggr; and a field-independent activation energy&Dgr;H0can be produced when different types of disturbed bonding states are mixed during time-dependent breakdown testing ofSiO2thin films. While &ggr; for each defect type alone has the expected1/Tdependence and&Dgr;H0shows a linear decrease with electric field, a nearly temperature-independent &ggr; and a field-independent&Dgr;H0can result when two or more states are mixed. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120493

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A large diameter thin annular intense relativistic electron beam was modulated at a frequency of 10 GHz. The electron beam propagated inside a narrow annular drift tube in which gaps feeding radial cavities were inserted. An external source injected microwave power of 180 kW into a single input cavity followed by a simple idler structure. A stable 10 kA rf current modulation was induced on the 400 keV electron beam. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120494

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

In this letter, we report on spatially selecting and grafting a DNA-tethered bead to an atomic force microscope (AFM) cantilever, using an optical tweezer. To quantify this technique, we measure force versus extension of a single DNA molecule using AFM. For such studies, we have developed a micromanipulation approach by combining an AFM, an optical tweezer, and visualization setup. The ability to select a single DNA polymer and specifically graft it to a localized position on a substrate opens up new possibilities in biosensors and bioelectronic devices. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120495

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Barium ferrite(BaFe12O19)was elaborated and investigated in this work in terms of its capacitance-temperature characteristics. The curve taken at the fixed frequency of 1 kHz shows anomalous negative values of capacitance over the high-temperature regime. A complete analysis of this effect is carried out by performing ac measurements at various temperatures. The results indicate that a resonance phenomenon, arising from the external electrical circuit and shifting from the higher frequencies to the lower ones with increasing temperature, is responsible for this unusual effect. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120496

出版商:AIP    

年代:1997

数据来源: AIP