摘要:

The strength and fatigue properties of borosilicate crown (BSC‐2) optical glass were measured at various temperatures within the range 20°K to 296°K. Simple beam specimens with two‐point loading were tested in both the abraded and unabraded condition. The breaking stress for a given condition increases with decreasing temperature. The fatigue decreases with decreasing temperature but still exists at 76°K.

ISSN:0021-8979    

DOI:10.1063/1.1722812

出版商:AIP    

年代:1957

数据来源: AIP

摘要:

Approximate analytic expressions are obtained for the ``effective band widths'' and emissivities of diatomic molecules at elevated pressures.The absorptivities of molecular vibration‐rotation bands are evaluated for radiation emitted by similar molecular vibration‐rotation bands and for radiation emitted by blackbodies. The results obtained for the absorptivity calculations compare favorably with available empirical correlations for H2O.The postulated model does not apply to CO2and, therefore, no satisfactory theoretical formula has been derived for the absorptivities of this molecule. The appendix (by A. Thomson) is devoted to a critical examination of the limits of validity of the effective band‐width concept for different molecules.

ISSN:0021-8979    

DOI:10.1063/1.1722813

出版商:AIP    

年代:1957

数据来源: AIP

摘要:

End correctionsnfor the capillary flow of some polyethylenes have been determined as a function of shear rateGn. The end correction term increases slowly at first with logGn, but as the shear rate approaches the critical value at which the extruded filament becomes rough, bothnanddn/dlogGnincrease very rapidly. At the critical shear rate there is an abrupt decrease indn/dlogGn, and at higher shear ratesnincreases very slowly with logGn, with the slopedn/dlogGnbeing practically constant. All flow curves for a given polyethylene, obtained using capillaries of length to radius ratio ranging from zero to thirty, could be reduced to one single master curve by calculating effective shear stresses using the appropriate values of the end correction termn, with no apparent decrease in viscosity even for short capillaries in which the transit time of the polymer is very short.

ISSN:0021-8979    

DOI:10.1063/1.1722814

出版商:AIP    

年代:1957

数据来源: AIP

摘要:

The electromagnetic backscattering properties of an infinite conducting cylinder coated with a lossless dielectric layer of thickness comparable to a wavelength is investigated both theoretically and experimentally. The theoretical problem is first formulated with three regions of arbitrary constants and then reduced to the specific cases. The experimental investigation utilizes the parallel‐plate‐region technique modified to permit the application of the Doppler shift principle. The scattering obstacle is set in motion in the presence of a plane‐wave electromagnetic field in the parallel‐plate region, and the detected Doppler signal is directly proportional to the backscattered field of the obstacle in question. The theoretical and experimental results are in excellent agreement.

ISSN:0021-8979    

DOI:10.1063/1.1722815

出版商:AIP    

年代:1957

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1722817

出版商:AIP    

年代:1957

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1722819

出版商:AIP    

年代:1957

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1722821

出版商:AIP    

年代:1957

数据来源: AIP