摘要:

Measurements of the energies and intensities of gamma rays associated with decay of138Nd,138Prm, and138Prghave been performed using a Ge(Li) detector. The branching ratio to a previously unreported excited level of138Pr (328.1 keV) has been measured, thus allowing for direct measurement of the decay of138Nd. Half-lives of 2.20 ± 0.07 and 5.04 ± 0.09 h have been measured for138Prmand138Nd, respectively. Decay schemes for138Prm → 138Ce and for the decay chain138Nd → 138Prg → 138Ce are proposed.

ISSN:0008-4042    

DOI:10.1139/v70-360

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The conformations of the radicals of biphenyl, diphenylmethyl, and some of their methyl substituted derivatives were investigated by calculating the π-electron delocalization energy and the non-bonded repulsions between the rings. The barriers to rotation are also reported.

ISSN:0008-4042    

DOI:10.1139/v70-361

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Absolute propagation and termination rate constants have been measured for the liquid phase autoxidation of some α-substituted toluenes at 30 °C. Rate constants for reaction of α-substituted toluenes with their own peroxy radical and with thet-butylperoxy radical have been compared. It would appear that the reactivity of an α-substituted benzylperoxy radical depends on the nature of the α-substituent.Reactivities of α-substituted toluenes towards thet-butylperoxy radical, the bromine atom, and the phenyl radical have been compared.

ISSN:0008-4042    

DOI:10.1139/v70-362

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Investigation of the kinetics of oxygen inhibition of the thiyl radical catalyzed isomerization ofcis-butene-2 has yielded an estimate for the relative rates of oxidation (k7) and decomposition (k3) of the CH3S and olefin adduct radical. At 25 °C,k7/k3 = 7 × 104 l mole−1, andE3 − E7 = 11.8 ± 2.5 kcal. Making use of these results, a new method has been developed for determining relative reactivities of olefins, and some preliminary results have been obtained.

ISSN:0008-4042    

DOI:10.1139/v70-363

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Various normal lower ammines and high-energy modifications of the lower ammines of cobalt(II) sulfate and nickel(II) sulfate have been prepared and the heats of solution in dilute ammonia have been measured for both types. For each of these ammine systems the maximum difference in heat of solution, expressed as kcal/mole of each heptaammine, between the high-energy and the normal salts has been found to be in close agreement with the ligand field splitting energy of the hexaamminemetal(II) ion.

ISSN:0008-4042    

DOI:10.1139/v70-364

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

γ-Irradiated glasses of methyltetrahydrofuran at 77 °K exhibit photoconductivity on illumination with visible light. A variety of kinetic effects are observed as the wavelength of the exciting light is changed from blue to the near infrared. It is suggested that, due to the coulombic field of the positive ions in the glass, some electrons can be released by red light while others can be released only by blue light. A thermally unstable red sensitive center can also be formed in the glass during illumination with blue light. This unstable center could be a dielectron.

ISSN:0008-4042    

DOI:10.1139/v70-365

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

A series of triphenylphosphine stabilized platinum dialkyl compounds of the type (Ph2P)3PtR2where R = methyl, ethyl, ethyl-d3,n-propyl,n-butyl, andn-hexyl have been synthesized and their infrared spectra in the CH stretching region have been obtained. These spectra are discussed in terms of the infrared spectra of hydrocarbons which are chemisorbed on transition metal catalysts.

ISSN:0008-4042    

DOI:10.1139/v70-366

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The influence of solvent effects and hydrogen bond formation on the anharmonicity of the NH stretching vibration of simple secondary amides, lactams, anilides, indole, pyrrole, and imidazole have been studied; and the frequencies of the first and second overtones, their half widths and solvent shifts measured. The validity of Buckingham's theory is established in the case of inert solvents; whereas the second order perturbation treatments are shown to be inapplicable to the case of hydrogen bonding solvents. All NH stretching modes seem to exhibit the same anharmonic behavior which is very different from that of OH vibrations.

ISSN:0008-4042    

DOI:10.1139/v70-367

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The stability of some cyclic N,N-disubstituted dithiocarbamates has been studied by the analysis of the decomposition rates at different pHvalues. It is concluded that the most important factors which determine the relative stabilities of three cyclic dithiocarbamates (DTC) are the solvation of the DTC acid molecule and the ring strain associated with the substituents. This has been proven by a study of (a) the decomposition rates as a function of the dielectric constant of the medium, (b) order of the stability, and (c) activation energy.The molar absorptivities and the apparent acid dissociation constants have been determined for pyrrolidine-, piperidine-, and hexamethylene-dithiocarbamates.

ISSN:0008-4042    

DOI:10.1139/v70-368

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The pore structures of a number of silica gels have been examined by low-temperature (−196 °C) nitrogen adsorption isotherms and these data compared with information obtained from electron photomicrographs. Good general agreement was obtained in the comparison, although the electron photomicrographs reveal more details regarding pore arrangements and dimensional variations. Gel structures were modified by heating and also by treatments with superheated steam or nitric acid. The aggregation of ultimate particles is affected by the steam treatment and this phenomena is compared with the preliminary stages of accepted sintering mechanisms.

ISSN:0008-4042    

DOI:10.1139/v70-369

出版商:NRC Research Press    

年代:1970

数据来源: NRC