摘要:

On the basis of the work done by Darling and Dennison on the water vapor molecule, the vibrational constants of acetylene are calculated, taking into account the resonance interaction arising from the near equality of the fundamentals ν1and ν3. Seventeen band centers are known experimentally. The band centers depend on the 10 constants χi, χikand γ which are functions of the potential constants. The expressions for the vibrational energies of the band centers are set up, those for interacting doublets or triplets being found by perturbation methods. The 10 constants are determined and the positions of eight bands calculated to check the results. The agreement is very satisfactory. The positions of 10 other bands not yet observed are predicted.

ISSN:1923-4287    

DOI:10.1139/cjr48a-025

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The radiography of steel by the use of the gamma rays from radium is discussed. The thickness of lead front screen which yields the maximum intensifying effect is determined and the action of the front screen discussed. Sensitivity curves are obtained using a slotted wedge steel penetrameter for a number of the commonly used types of X-ray film. It is shown that the thickness of the lead front screen which produces the maximum density on the film is not necessarily the most useful thickness for gamma radiography. The most useful thickness is determined from penetrameter sensitivity curves. The importance of these sensitivity curves for routine gamma ray testing is indicated.

ISSN:1923-4287    

DOI:10.1139/cjr48a-026

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

Sound absorption measurements, made with a diverging beam in sea water, are given. They cover frequencies from 0.35 to 2.3 Mc. per second and are somewhat lower than those given by Richardson for fresh water. Conclusive comparison between these results and fresh water results cannot be made. Advantages of using long distances are discussed.

ISSN:1923-4287    

DOI:10.1139/cjr48a-027

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

At least two energy level schemes have been proposed for the ThC′ nucleus, which is excited in the β-disintegration ThCC′. That of Ellis (1933) includes three γ-rays of energies 0.726, 1.62, and 1.80 Mev., the 1.62 Mev. ray being doubtful. The level scheme of Latyschev and Kulchitsky (1940) has eight γ-rays including one of energy 2.2 Mev., for which no corresponding long-range α-particle group has been observed. The two level schemes lead to widely differing values for the total γ-ray energy of ThCC′. In the present investigation a value for the total γ-ray energy of ThCC′ has been obtained by measuring coincidences between the γ-rays of ThCC′ and the subsequently emitted α-particles of ThC′. It is shown that this value (0.14 Mev.) favors the level scheme of Ellis, including only the γ-rays of energy 0.726 and 1.80 Mev., and taking the former as electric quadrupole. It was found that under certain conditions the external bremsstrahlung excited by the β-rays of ThCC′ in the source-holder contributed appreciably to the coincidence rate. Precautions were taken to minimize this effect.

ISSN:1923-4287    

DOI:10.1139/cjr48a-028

出版商:NRC Research Press    

年代:1948

数据来源: NRC