摘要:

The theory of the mercury arc rectifier is applied to the problem of rectification and detection of alternating currents by vacuum tubes, in radio work, and the meaning of the conventional detector formula is discussed in terms of this theory. For comparison the rectifying action produced in discharge tubes by virtue of their falling characteristic is calculated. The design of filters for smoothing out the rectified current is treated by making use of the results obtained from telephonic transmission lines. By means of the formulæ given for the different cases a comparison can be made between the filters with capacitance input used since 1925, and the type of filters which should be used in order to prevent temporary overloading of the power tubes. The chief experimental methods for testing the theory, and for examining the rectified current, are indicated; the advantages of the glow discharge tube oscillograph are pointed out, and its use in testing work is proposed in place of the methods hitherto followed.

ISSN:1923-4287    

DOI:10.1139/cjr30-009

出版商:NRC Research Press    

年代:1930

数据来源: NRC

摘要:

A discussion is given as to the nature of the factors involved in the mechanism of the formation of cyclic acetals and ketals from carbonyl and polyhydroxy derivatives. It is shown that in the two reactions involved, namely, the primary formation of a half-acetal, followed by removal of water and ring-closure, the polarity of the carbonyl derivative plays a very important rôle. Chloral combines with polyhydroxy compounds to give exceptionally stable half-acetals, which can be converted into the cyclic derivatives by the use of strong dehydrating agents.In contrast with the behavior of other aldehydes it is found that the condensation of chloral with glycerol yields only one ring compound, namely the five-membered derivative. No satisfactory explanation of this can, as yet, be given.The identity of the trichloroethylidene glycerol obtained by the condensation of glycerol and chloral under the influence of concentrated sulphuric acid has been established as a five-membered cyclic acetal by a comparison of the properties of its methyl ether with those of trichloroethylidene glycerol α-methyl ether prepared from glycerol α-methyl ether.

ISSN:1923-4287    

DOI:10.1139/cjr30-010

出版商:NRC Research Press    

年代:1930

数据来源: NRC

摘要:

Sodium tetrathionate and cyanogen bromide in water have a specific oxidizing action on alkali xanthates, the latter being smoothly converted to xanthogen disulphides without the formation of by-products. Cyanogen bromide in alcohol converts xanthates into xanthogen monosulphides. Other new reagents for the oxidation of xanthates to xanthogen disulphides under certain conditions are—nitrous acid, nitrosyl chloride, chloramine-T, benzene sulphonyl chloride.The following new xanthogen disulphides, viz.,n-hexyl (liquid), β-ethoxyethyl (liquid), β-phenylethyl (m.p. 49.5–50°), and the following new xanthogen monosulphides, viz.,n-hexyl (liquid), benzyl (m.p., 82.5°), β-ethoxyethyl (liquid), are described. β-phenylethyl xanthogenamide (m.p., 79°) is also described.Pyrolysis of β-phenylethyl xanthogen disulphides yields styrene.

ISSN:1923-4287    

DOI:10.1139/cjr30-011

出版商:NRC Research Press    

年代:1930

数据来源: NRC

摘要:

This paper describes a case of the transfusion of material from one solid to another under the influence of heat, which, it is suggested, may throw light upon certain metamorphic processes at work in the earth's crust.

ISSN:1923-4287    

DOI:10.1139/cjr30-012

出版商:NRC Research Press    

年代:1930

数据来源: NRC

摘要:

The numbers and mating capabilities of the chromosomes were determined in a good many F2plants and their offspring in two crosses between common (42-chromosome) wheat and emmer (28-chromosome) types. In general the results confirmed those of Kihara and supported his conclusions. Chromosome numbers were much nearer those of the parental types than was to be expected if all germ cells were capable of functioning and all zygotes of developing. A large number of expected chromosome types did not appear at all. A high percentage of F2had only 14 bivalent chromosomes and zero to seven univalents. These tended to revert rapidly to the 14-bivalent condition of emmers. F3in this group did not have more than 14 bivalents nor more univalents than their F2parents. A chromosome formula for all of the group of F2with more than 14 bivalents may be written (14+x) bivalents +(7−x) univalents. Thesetended to revert to the 21-bivalent condition of common wheat. F3in this group did not have fewer bivalents nor more univalents than their F2parents. Occasional plants were exceptions to these rules.

ISSN:1923-4287    

DOI:10.1139/cjr30-013

出版商:NRC Research Press    

年代:1930

数据来源: NRC