摘要:

The temperature distribution and the total radiated power are computed for a bar undergoing zone refining in vacuum, using a one‐dimensional analysis. Radiated power experiments were performed on Al, Ge, Gd, Si, Ni, Fe, Pt, Pd, V, Mo, Ta, and W using an electron‐bombardment zone‐refining furnace operated with space‐charge limited current. The experiments agreed well with the predictionP=4&pgr;(e&sgr;k/5)12R32T52for a very thin bar with an infinitesimal zone length.

ISSN:0034-6748    

DOI:10.1063/1.1717516

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The construction of iron‐cored electromagnets using aluminum foil magnetizing coils is described. A satisfactory procedure for making the coils is discussed in detail. Performance data for a small closed yoke magnet are presented, and the advantages of a system of this kind considered.

ISSN:0034-6748    

DOI:10.1063/1.1717517

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Pulsed magnetic fields greater than 100 koe and of microsecond duration are reported here to be readily producible in millimeter‐diameter coils supplied by energy storage units of only several joules capacity. Demonstrative experiments are described which show the magnetic‐state transitions of a 20‐&mgr;g specimen of MnAs near 90 koe, the shift in transition temperature when the specimen and coil are subjected to hydrostatic pressures up to 850 atm, and the reversal of magnetization of a 0.5‐&mgr;g iron cube from which all reverse nuclei were driven presumably.

ISSN:0034-6748    

DOI:10.1063/1.1717518

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

An automatic device to develop nuclear plates has been built in our Laboratory. The replacement or the dilution of the liquids and the changes and stabilization of the temperatures are controlled by an electronic program device using a transparent tape and a connection matrix. This system presents the advantage of great flexibility and ensures total reliability. Use is made of temperature development in wet conditions. Tests showed homogeneity and reproducibility within 1%.

ISSN:0034-6748    

DOI:10.1063/1.1717519

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The construction and procedure for use of a special‐purpose chromatograph designed to analyze small amounts of helium in natural gas streams are described. The successful use of ordinary solenoid valves for column switching is unique. Automatic‐zero circuitry is also mentioned. The instrument has proved to be useful in the reduction of wasted helium in the outlet gas streams from helium extraction plants.

ISSN:0034-6748    

DOI:10.1063/1.1717520

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A versatile, all transistor silicon 4‐point probe resistivity meter incorporating a dc probe bias supply in conjunction with an ac measuring circuit is described. It is direct reading and covers a resistivity range of from 0.01 ohm‐cm full scale to 300 ohm‐cm full scale. With minor changes the range can be increased to 1000 ohm‐cm.

ISSN:0034-6748    

DOI:10.1063/1.1717521

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

An apparatus has been constructed for comparative density measurements in solids. The method is based on the measurement of the level of flotation of a series of specimens in a known density gradient, introduced in a column of liquid. The description of the apparatus, a discussion of the method, the measuring procedure, and the precision is given.

ISSN:0034-6748    

DOI:10.1063/1.1717522

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A simple electron beam furnace for Knudsen effusion studies is described. Temperatures as high as 2700°K have been maintained in this system at pressures of the order of 10−6mm Hg.

ISSN:0034-6748    

DOI:10.1063/1.1717523

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A means is described whereby the liquid level of sodium or other conducting liquids may be determined within a sealed metal system. The measurement obtained is that of electrical resistance in an attached drain tube used as a metal ``sight tube.'' A large alternating current is induced for the measurement by using the sealed metal system itself in conjunction with the ``sight tube'' as a one turn secondary of a transformer. Techniques necessary for application and temperature compensation are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1717524

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

An improved technique for measuring the burning rate of experimental propellants is described. By using a thick ¼‐in. i.d. Lucite cylinder to hold the propellant grain, none of the usual inhibition problems are encountered. In addition, since the Lucite does not char on burning, the technique is ideally suited for high speed window bomb photography. Although this technique was developed for the measurement of the burning rate of solid propellants, also liquids, pastes, gels—hygroscopic materials—can all be handled with equal facility.

ISSN:0034-6748    

DOI:10.1063/1.1717525

出版商:AIP    

年代:1961

数据来源: AIP