摘要:

This improved gravimetric vapor‐sorption apparatus was designed for vapor‐sorption measurements at 20–50°C with condensable vapors, e.g., water and organic vapors on inorganic and organic adsorbents, such as minerals and resins. The apparatus can be readily adapted to low‐temperature adsorption of noncondensable gases, e.g., N2, Kr, and Ar. The system consisted of a helical spring (quartz or tungsten) sorption balance. A Pirani gauge and a mercury manometer permitted the measurement of vapor pressures from several microns to more than 100 mm. Important considerations relevant to the design of helical springs (quartz or metal) were summarized, and a comparative evaluation was made of the advantages and limitations of tungsten and quartz helices. A practical high‐vacuum Teflon seal for use in place of greases and waxes on ground glass joints was developed. This seal was designed for use with organic vapors. The aqueous vapor pressures at 20°C were measured for a wide range of concentrations of aqueous sulfuric acid solutions. These data were in excellent agreement (of the order of 1%) with the published data down to pressures of 1 mm of mercury, and they provided a reliable indication of the accuracy of the vapor pressures measured with this apparatus.

ISSN:0034-6748    

DOI:10.1063/1.1717245

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A continuous casting apparatus has been developed that will produce thermoelectric material rapidly, reliably, and in large quantities with a minimum amount of labor. Bismuth telluride and alloys of Bi2Te3, Sb2Te3, and Bi2Se3were cast in rods up to 70 in. in length. The deviation of the thermoelectric properties throughout the length of the rods was less than 5%.

ISSN:0034-6748    

DOI:10.1063/1.1717246

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

This paper describes a mechanical scanning device for evaluation of microscopic data over a large area and an electronic system for collecting and sorting information about the size of light and dark patches on a plate. Preliminary experiments for measuring the size distribution of the islets of Langerhans in histologic sections of the pancreas are described.

ISSN:0034-6748    

DOI:10.1063/1.1717247

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A modified type of secondary electron monitor useful for the monitoring of low energy electron beams during irradiation is described. Using the window foil at the end of the accelerator as a part of the detector, it is designed to have minimum disturbance on the primary beam. The monitor output is independent of the primary beam energy and proportional to the primary beam current in the range over which the monitor was tested (1.0–1.7 Mev and up to 120 &mgr;a).

ISSN:0034-6748    

DOI:10.1063/1.1717248

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

An apparatus suitable for the measurement, in vacuum, of the residual stress in evaporated metal or dielectric films has been built and tested. The substrate on which the film is deposited is clamped at one end to form a cantilevered beam. When the substrate is bent as a result of the film stress, the force required to restore the beam to its initial position is measured. The stress is then calculated from a knowledge of the restoring force, the beam dimensions, and the film thickness. A stress of 5×107d/cm2can be easily detected and measured with this apparatus.

ISSN:0034-6748    

DOI:10.1063/1.1717249

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

An arrangement of a needle and a sonic orifice has been developed which is capable of converting the corona current into free small ions with 100% efficiency. Positive and negative ion concentrations of 1011ions/cm3in the sonic jet and total ion outputs of 1014/sec have been achieved using 2.5 cfm of free air at 30 psig through a116−in. orifice. Theoretical and experimental studies of the ion decay rate in the jet show that the concentrations drop off approximately as the square of the distance from the ionizer.

ISSN:0034-6748    

DOI:10.1063/1.1717250

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A 40‐w electrodeless rubidium light source is described which emits a total of 13 w in the two D lines. The intensity is a factor of 50 larger than that of a previously reported electrodeless rubidium source. In addition, high stability, long life, minimum noise, and the absence of self‐reversal make it attractive for optical pumping studies of alkali metal vapors.

ISSN:0034-6748    

DOI:10.1063/1.1717251

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A telescope is described which has been used to determine the directional characteristics of the Cˇerenkov radiation accompanying extensive cosmic ray air showers. The reflecting telescope has a 12.5‐in. aperture, a 48‐in. focal length and is of an off‐axis design to permit the use of a 19 photomultiplier tube light detection array. Pulse‐height information from each tube is fed to separate, spaced inputs on a delay line which supplies the resulting signal for oscilloscope presentation. The various pulse heights provide the Cˇerenkov radiation directional information. An average of 75% of the Cˇerenkov photons arrive at the telescope within a half‐angle of 2.3°.

ISSN:0034-6748    

DOI:10.1063/1.1717252

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Experimental apparatus designed to measure the secondary electron emission from solids at low primary electron energies is described. The design permits the determination of the normal velocity distribution of secondary electrons off insulating targets. Some of the usual difficulties associated with measurements of this kind are avoided through the use of an orthicon‐type deflection system to separate primary and secondary beams. Measurements of the secondary emitting properties of molybdenum, some of which are performed under pulse conditions appropriate for insulating targets, are described and serve to demonstrate the performance of the apparatus.

ISSN:0034-6748    

DOI:10.1063/1.1717253

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A method of determining some of the characteristics of a deuterium plasma generated and confined in a magnetic‐mirror machine is described. In this case the electronic component of the plasma is characterized by a mean energy considerably greater than the ionic component. The mirror configuration readily allows detection of the flux of particles which escape through the mirror loss cone from the plasma confined between the mirrors. Scintillator probes placed near a mirror and outside the confinement region do not interfere with the confined plasma. By the use of thin aluminum absorbers placed in front of the scintillator, a determination was made of the energy distribution of the electron flux as a function of time during the decay of the pulsed mirror field. Such measurements were used to infer plasma conditions by consideration of the processes resulting in the leakage of plasma particles through the mirror. In determining the density of the plasma, the correction to be made to the integral of electron flux over time is based on conclusions as to plasma stability and the known decay rate of the pulsed magnetic field.

ISSN:0034-6748    

DOI:10.1063/1.1717254

出版商:AIP    

年代:1961

数据来源: AIP