摘要:

The design and operating characteristics of a two‐frequency radiometer operating in the 50–60 GHz band are described. The system was developed as a remote sensor of the vertical temperature profile in the lower atmosphere. Recent applications of the system as a temperature probe are summarized.

ISSN:0034-6748    

DOI:10.1063/1.1686802

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The thermopowers of some low temperature thermocouple wires have been measured from 4.2 to 100 K in magnetic fields up to 100 kG. Our technique is designed to circumvent the usual problems of temperature measurement in high magnetic fields. Some representative curves which display the absolute thermopowers of Au&sngbnd;0.07 at.%Fe, Chromel P, and ``Silver Normal'' in a transverse magnetic field are presented. A complete set of calibration tables for thermocouples of type Chromel P vs Au&sngbnd;0.07 at.%Fe and type ``Silver Normal'' vs Au&sngbnd;0.07 at.%Fe have been prepared and are available upon request.

ISSN:0034-6748    

DOI:10.1063/1.1686803

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

By use of a special steel cylinder and a multilayer Teflon‐neoprene Bridgman sealed piston, it is possible to achieve cold oxygen pressures of 4 kilobars—the limit of the remainder of the high pressure system.

ISSN:0034-6748    

DOI:10.1063/1.1686804

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A simple and relatively inexpensive method is described for measuring the rate and extent of the reaction of coal with hydrogen under conditions of commercial interest. A thin layer of pulverized coal is supported on an electrically heated metal screen strip capable of initial heating rates of 600–12 000°C/sec followed by extended time at final temperatures of 400–200°C. The device is enclosed in a vessel designed for hydrogen pressures up to 205 atm. Typical results are illustrated and shown to compare favorably with data from previous investigations.

ISSN:0034-6748    

DOI:10.1063/1.1686805

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The response of Kodak fine grain positive and Kodak no‐screen (duplitized) film was measured as a function of x‐ray energy over the range of approximately 4–52 keV under a vacuum of 10−3−10−4Torr. The x‐ray transmission properties were also determined. The calibrations were performed with fluorescence radiation excited by the bremsstrahlung from dc x‐ray machines. These two films can cover an exposure range of over three orders of magnitude. Some films, such as fine grain positive, exhibit an enhanced sensitivity if exposed under vacuum. Also, it was found that no‐screen film exhibits a sensitivity reversal at approximately 5 keV. Other films would be expected to show a similar response with the energy at which the reversal occurs determined by the characteristics of the emulsion.

ISSN:0034-6748    

DOI:10.1063/1.1686806

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Determination of atomic and molecular lifetimes by delayed coincidence photon counting with photomultipliers two or more years old may lead to erroneous results caused by afterpulses and even direct photodecay in perfused helium. Spurious lifetimes as low as 15 nsec for theB2&Sgr;u+(v′=0)state ofN2+and the C3&Pgr;g(v′ = 0) state of N2have been observed.

ISSN:0034-6748    

DOI:10.1063/1.1686788

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Energy delivered by a single pulse of current or voltage to a nonlinear resistor is obtained from the area measurement of a charge (q)‐voltage (v) phase portrait display. The technique is demonstrated by an apparatus employing a half‐sine wave pulse current waveform.

ISSN:0034-6748    

DOI:10.1063/1.1686789

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

We have designed and built an inexpensive electronic ramp generator which also incorporates the excellent hold‐time characteristics of a mechanically operated ramp generator.

ISSN:0034-6748    

DOI:10.1063/1.1686790

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

This paper describes a magnetometer with a miniature transducer which can be scanned automatically. The active area of the transducer is 0.64×0.76 mm and its drive circuit is constructed from wire plated with a magnetic coating. The magnetometer is capable of detecting static magnetic fields as low as 0.02 Oe and can measure magnetic fields as close as 0.08−0.10 mm from a relatively flat surface since the transducer is flat and rugged. The magnetometer is simple to operate and has a fast response. The instrument has been applied to the measurements of magnetic fields arising from remanent magnetization in experimental plated‐wire memory planes and regions of magnetic activity in geological rock specimens.

ISSN:0034-6748    

DOI:10.1063/1.1686791

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Ion chambers having a polished MgF2window and filled with nitric oxide gas have been developed for the measurements of absolute intensities of solar and geocoronal hydrogen Lyman‐&agr; radiation. The area sensitivities of the detectors and the effects of moisture on the transmittances of MgF2single crystals were measured and compared with those in the cleaved LiF cases. The results indicate that an ion chamber with a polished MgF2window has a superior suitability for the reliable measurement in rocket and satellite experiments as well as in laboratory work.

ISSN:0034-6748    

DOI:10.1063/1.1686792

出版商:AIP    

年代:1974

数据来源: AIP