摘要:

Using paralleled power transistors driven by a transistor and a chopper amplifier, supplemented by a coarse feedback loop to the generator field, we have regulated to <0.001% the field of an electromagnet requiring 80 amp at 200 v. The dissipation in the regulator is 250 w. The magnet current may be varied from zero to maximum by setting the reference potentiometer to the appropriate voltage, and sufficient protective measures are incorporated so that the circuit is not injured by misuse. The circuit is usable to perhaps a megawatt.

ISSN:0034-6748    

DOI:10.1063/1.1716473

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A Teflon‐covered, combined silver silver‐chloride platinum polarographic electrode mounted in a heart catheter is described. The advantage and characteristics of this particular construction are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1716474

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A high‐current ion source is described that is of simple design and construction. It is capable of producing an ion beam of ½ amp. The energy spread of the ions is large.

ISSN:0034-6748    

DOI:10.1063/1.1716475

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The thermoelectric force developed by the following junctions up to 2200°C has been measured: RevsW, RevsMo, RevsW‐30Re, and RevsMo‐50Re. The thermoelectric force for WvsW‐30Re and MovsMo‐50Re has been calculated. The RevsW junction develops about 15 mv at 1000°C and may be usable up to 2600°C. RevsMo develops about 17 mv at 1000°C; the thermoelectric power is low above 1600°C. The outputs of RevsW‐30Re and RevsMo‐50Re couples are low and change signs at about 1200 and 1800°C, respectively. The calculated outputs of WvsW‐30Re and MovsMo‐50Re are high; the WvsW‐30Re output is nearly linear over a wide range in temperature, and the thermocouple should be useful to about 2600°C. All of these couples must be used in vacuum or in neutral or reducing atmospheres.

ISSN:0034-6748    

DOI:10.1063/1.1716476

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A description of an instrument for measuring C14, percent CO2, and C14specific activity in the breath of human subjects is presented. Ionization chamber assay for the C14is used. The design parameters of radioactivity sensitivity and response time are discussed. For simple carbon‐14 metabolites some 1 to 10 &mgr;C are required for an eight‐hour respiration analysis with this instrument.

ISSN:0034-6748    

DOI:10.1063/1.1716477

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

An adiabatic calorimeter designed primarily for measurements on bulk metal samples is described. Details of the calorimeter design and operation are given. Experimental problems associated with precise high‐temperature measurements are emphasized. Measurements from room temperature to 1000°C have been made and include determinations of specific heats, heats of transformation, and heats of solution. Representative data on pure nickel are shown with reported accuracy of ±0.5%.

ISSN:0034-6748    

DOI:10.1063/1.1716478

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

Gas flow through capillaries obstructed by wire inserts was investigated for ratios of core to capillary diameters (B/A's) of 0.08 to 0.9. For a given core‐capillary combination, laminar and turbulent as well as an intermediate region are well defined. Deviations from Poiseuille flow for the range ofB/A's are presented in a working curve, which will give flow rates for laminar flow correct to from 5 to 10%.The pressure dropvsflow curves for the intermediate and turbulent flow regions are reasonably reproducible. The use of the cored capillary for very small leak rates looks especially attractive because, with largeB/A's such that the maximum crescent clearance is less than 0.25 mm, the onset of turbulence is postponed to much higher pressure drops.

ISSN:0034-6748    

DOI:10.1063/1.1716479

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

It is shown that the cost of using liquid neon as a coolant in the temperature range 20 to 30°K is not prohibitive. A simple method of condensing the gas is described, and an example of an experiment performed with liquid neon is given.

ISSN:0034-6748    

DOI:10.1063/1.1716480

出版商:AIP    

年代:1959

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1716481

出版商:AIP    

年代:1959

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1716482

出版商:AIP    

年代:1959

数据来源: AIP