摘要:

The ionization produced by individual fission fragments over various lengths of track starting from the origin was measured in a pulse ionization chamber provided with a grid. The distribution of electron pulse sizes for the complete track showed the well known two peaks. As the length of track was diminished, the peaks corresponding to the high and low energy groups of fragments approached each other and merged together at a track length of about 6 mm. in nitrogen. In smaller distances measured from the beginning of the track the difference in ionization by the two groups of fragments was found to be small, and the two groups could not be resolved. From the progressive change in shape of the pulse spectrum it is tentatively concluded that the low energy group produces the greater initial ionization. The average energy spent in ionization by the fragments in the first. 1.1, 2.3, and 5.3 mm. of their tracks was measured in nitrogen and found to be 7.6, 15. 0, and 34.6 Mev. respectively. In the course of this work an effect due to the formation of negative ions by electron attachment was observed in the chamber filled with argon. Examination of this effect suggests that, at high collecting fields, formation of negative ions, perhaps in impurities such as oxygen and water vapor, is more pronounced in argon than in nitrogen.

ISSN:1923-4287    

DOI:10.1139/cjr48a-012

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The several modified Kozeny equations for the measurement of the specific surface of fine powders by gas-permeability methods have been compared. The equations all give very similar surface area values for a set of experimental data. The physical significance of the empirical constants used is discussed and preference is indicated.

ISSN:1923-4287    

DOI:10.1139/cjr48a-013

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The results are presented of ionosphere measurements made in the region of totality during the eclipse of July 9, 1945. An analysis of the results shows effective recombination coefficients of 1.6 × 10−8forEregion, 1.4 × 10−8forF1region, and 1.0 × 10−9forF2region. Evidence of a variable coefficient forEregion agrees with the suggestion of Massey and others of a high negative ion density at this level.

ISSN:1923-4287    

DOI:10.1139/cjr48a-014

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

This is an electronic circuit useful in the control of electric air-bath furnaces having a long time lag. The control is accomplished by means of a relay that shunts a portion of the resistance in series with the furnace winding. The thermometric device is a thermocouple connected in series with a mirror-type galvanometer and a variable voltage supplied by a potentiometer. The setting of the potentiometer selects the temperature at which the device will control. A light beam falling on the mirror is reflected to one of two photocells. One photocell closes the shunt by means of the described circuit and increases the current in the furnace. This condition is maintained until the beam moves across the second photocell, when the shunt is again opened. The device will control temperatures over 1000 °C. within a precision of ± 2 °C. over any desired length of time.

ISSN:1923-4287    

DOI:10.1139/cjr48a-015

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The photoelectric temperatures of 52 P Cygni stars of spectral type from A4 to O5 have been determined from emission lines by Zanstra's method. For approximately half the stars, accurate spectrophotometric measures of emission line intensities were available and for the remainder the intensities were estimated on the basis of published descriptions of spectra. The computed temperatures were found to range from 10,000° to 42,000° K. and after smoothing by graphical methods a temperature scale for the O, B, and A type stars showed the following values: A0, 16,000°; B0, 35,000°; O5, 40,000° K. Comparisons are made with temperatures derived by other methods and reasons are given for attributing greater weight to the values from B0 to O5 than to those in the lower range of the sequence.

ISSN:1923-4287    

DOI:10.1139/cjr48a-016

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

A new method of investigating the angular motion of a shell in flight is described. This is a radio method wherein the fuse of the shell is replaced by a high frequency transmitter and the radiated signal is recorded at a ground station. The theory of the method is given, the equipment described, and the procedure in the analysis of the records is discussed. Results of experiments are quoted and values of the force coefficients are deduced. In addition to those coefficients usually determined by jump card experiments, certain other coefficients, involving spin, are evaluated. The radio method of measuring yaw is compared with other methods.

ISSN:1923-4287    

DOI:10.1139/cjr48a-017

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

Free air, Bouguer, and isostatic anomalies are listed in a table of principal facts for 23 stations established by the Dominion Observatory in the area between latitudes 55 and 70 degrees, bounded on the east by Hudson Bay and on the west by Athabaska, Slave, and Mackenzie rivers. There is some evidence that the predominantly negative anomalies at stations in the Pre-Cambrian may be due to lack of isostatic adjustment following removal of glacial loads.

ISSN:1923-4287    

DOI:10.1139/cjr48a-018

出版商:NRC Research Press    

年代:1948

数据来源: NRC