摘要:

Instrumentation for determining the absorption coefficient in a plasma in the optical wavelength region has been developed for the study of a hydrogen arc discharge. The arc column is scanned with a beam of its own radiation emitted from the central zone which usually displays the highest brightness. The accuracy of the attenuation measurements near the edges of the plasma column is significantly increased over the accuracy obtainable with the double‐path method. The described instrumentation produces a lateral scan of the plasma in digital form suitable for the computation of the spatial distribution of the absorption coefficient.

ISSN:0034-6748    

DOI:10.1063/1.1719707

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A technique is described for obtaining localized measurements of the ion density in a plasma which is not affected by the presence of a magnetic field or the absence of thermodynamic equilibrium. The technique consists basically of exciting the ions with a proton beam and relating the measured absolute intensity of certain spectral lines to the ion density. Three requirements are discussed which must be satisfied in order to apply the method to a particular gas. The technique appears to be well suited to measuring the density of helium ions. The possible sources of error are examined and, for helium plasmas, none of the errors are large provided that the gas pressure is less than 1 mm Hg and the temperature is over 10 000°K. A preliminary experiment is described.

ISSN:0034-6748    

DOI:10.1063/1.1719708

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

The design and performance of a versatile automatic recording spectrofluorometer are described. The instrument has a modular design and is capable of measuring fluorescence excitation and emission spectra, polarization of fluorescence, and phosphorescence spectra, each as a function of temperature andpH. Both right angle and frontal illumination may be used. A split beam optical system combined with an automatic gain control (AGC) amplifier assures long term stability and freedom from the effects of light source fluctuations. Corrected emission spectra in energy units are obtained automatically by the use of an adjustable function generator (Vernistat). A quantum counter used in conjunction with a second function generator and the AGC amplifier permits recording of true excitation spectra.

ISSN:0034-6748    

DOI:10.1063/1.1719709

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

Thermoelectric instabilities of some refractory metal thermocouples have been studied in the temperature range 1000–2000°C under vacuum and neutral atmospheres. The sources of instability were found to be complex, involving contamination from ceramic protection tubes and furnace environments, preferential volatilization, and various thermal anomalies such as recrystallization and phase changes in the refractory thermoelements. Refractory thermocouples and thermoelements were studied under a variety of conditions and emf changes associated with each are reported. Recommendations are presented for the selection and application of these thermocouples to attain maximum thermoelectric stability.

ISSN:0034-6748    

DOI:10.1063/1.1719710

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A superconducting magnet system composed of three separate, easily removable, nested solenoids is described. The outer two solenoids are split coil systems so that particle beams can be directed through the magnet when these sections are used to provide the magnetic field for a helium bubble chamber. Magnetic fields of 67, 42, and 17 kG have been achieved in winding diameters of 17.8, 27.9, and 45.7 cm, respectively. The results indicate that the system is capable of operation at fields in excess of 70 kG. The magnet is wound from various types of superconducting cable. Some of the considerations governing the choice of cable types and magnet design are given. A description of the tests is given, and the test results are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1719711

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

Better reproducibility, greater accuracy, and savings of time and reagents can be realized by omitting the usual procedure of setting up a linear concentration gradient when using a ``well stirred'' diaphragm type diffusion cell. The equation which describes the cell characteristics starting with pure solvent in the diaphragm and in one compartment and the concentrated solution in the other compartment is log[(1−&lgr;/6)&Dgr;Ci/&Dgr;Cf] = &bgr;Dt(1−&lgr;/6).

ISSN:0034-6748    

DOI:10.1063/1.1719712

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A rapidly responding gradient layer calorimetry system for experimental animals is described. Monitoring of radiant and evaporative components of heat loss is accomplished by separate heat exchange systems that employ thermoelectric heat flowmeters.Calibration and test results with the equipment show the following: The response to energy input is linear in both the radiant heat exchange system (radiant calorimeter thermopile) and the circulating air heat exchange system (ventilatory calorimeter thermopile); the radiant calorimeter thermopile signal is independent of the location of the heat source in the chamber, and when referenced to a cold junction temperature of 20°C, it has a response of 0.0212 mV/g·cal/min; the ventilatory calorimeter thermopile has a response of 0.0159 mV/g cal/min when referenced to a cold junction temperature of 4°C; the automatic temperature control systems for the two thermopiles provide ±0.01°C control at their respective temperatures; the noise‐to‐signal ratio is less than 1% for the radiant calorimeter thermopile and less than 2% for the ventilatory calorimeter thermopile at thermal input levels comparable to those expected from the experimental animal.

ISSN:0034-6748    

DOI:10.1063/1.1719713

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A metallograph has been constructed so as to permit the microstructural examination of the surface of metallurgical specimens during deformation and fracture at elevated temperature in a controlled environment. Auxiliary instrumentation provides for the recording of specimen elongation, load, load transients, and temperature on a time base. The rate of specimen elongation may be controlled independently of the load. Microstrain can be measured from the relative displacement of surface markings at the same time as the microstructural appearance is observed and photographed. Cine photography can be employed to record deformation or fracture sequences. In all circumstances a careful correlation is maintained between all the measured parameters.

ISSN:0034-6748    

DOI:10.1063/1.1719714

出版商:AIP    

年代:1965

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1719715

出版商:AIP    

年代:1965

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1719716

出版商:AIP    

年代:1965

数据来源: AIP