摘要:

Assuming an irreversible, random, end-to-end aggregation of a small percentage of potato X virus in tobacco sap, the flow birefringence parameters of such polydisperse systems have been calculated. The extinction angles χ were evaluated for different values of the ratioG/θ1(Ggradient θ1, rotary diffusion constant of non-aggregated virus) for preparations containing between 0 and 15% by weight of aggregated material. A particle length of 6200 Å for the non-aggregated virus particle was derived and an amount of 13–15% aggregated material was estimated.A partially purified and fractionated preparation of potato X virus was also investigated and an average particle length of 5400 Å was derived. Because of the possible contribution of small fragments, this length was taken as the lower limit.The flow birefringence – gradient curve indicated that the potato X virus behaves like a rigid particle. No evidence of flexibility was obtained from extinction angle – gradient measurements in the range 0.1–0 Mphosphate buffer concentrations at pH 7.2.

ISSN:0008-4042    

DOI:10.1139/v58-233

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

The steam-volatile oil of western red cedar contains traces of a fifth tropolone, β-dolabrin (4-isopropenyltropolone), in addition to α-, β-, and γ-thujaplicin and 7-hydroxy-4-isopropyltropolone. The presence of β-dolabrin, previously obtained from Japanese "Hiba" wood by Nozoe, was detected by paper chromatography and proved by isolation of a sample from the steam-volatile oil by a combination of sodium salt precipitation, fractional crystallization, and preparative paper chromatography. The approximate composition of the steam-volatile oil from butt heartwood is given.

ISSN:0008-4042    

DOI:10.1139/v58-234

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

The classical light-scattering theory for polymer solutions is extended to solutions of copolymers which may be polydisperse in chain composition as well as in molecular weight. It is shown that much too high molecular weights will result from light-scattering data for copolymers owing to fluctuations in chain composition; the magnitude of this effect increases rapidly as the absolute value of the refractive index increment approaches zero. The methods for determining the usual weight-average molecular weight and polydispersity of composition are described.The theory was tested with experimental results on: (1) a mixture of polystyrene and poly(methylmethacrylate), considered as a copolymer with the highest possible polydispersity of composition; (2) a high conversion, statistical copolymer of styrene and methylmethacrylate (copolymer I); and (3) a block copolymer of the same monomers (copolymer II). The apparent molecular weight for copolymer I (Mw = 1.83 × 105) varied markedly with refractive index increment in much the same way as the total molecular weight for the mixture. The molecular weight of copolymer II (Mw = 1.20 × 106) remained essentially constant in the same series of solvents. The polydispersities of composition obtained were 0.72 and 0.05 for copolymer I and II respectively compared with the maximum possible value equal to 1.0.

ISSN:0008-4042    

DOI:10.1139/v58-235

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

Bon nombre de formyldiphényl éthers ont été synthétisés en faisant réagir certains phénols avec la 2-chloro-5-nitrobenzaldéhyde ou la 3-nitro-4-chlorobenzaldéhyde. Plusieurs l'ont été en condensant le tosylate de la 5-nitrovanilline ou de la 4-hydroxy-3-nitrobenzaldéhyde avec divers phénols. Ces derniers ne donnent pas d'éthers avec la 2-chloro-5-nitrobenzaldéhyde; mais, cependant, les phénolates alcalins réagissent avec cette aldéhyde en solution alcoolique diluée. Par une série de réactions, les 2,2'-diméthoxy-4,4'-diformyl-6-nitro-, 2,2'-diméthoxy-4,4'-diformyl-, 2,2'-diméthoxy- 4,4'-bis-(β-carboxyvinyl)- et 2,2'-diméthoxy-4,4'-bis-(β-carboxyéthyl)-diphényl éthers ont été prepares.

ISSN:0008-4042    

DOI:10.1139/v58-236

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

The photoconduction of thin crystals of anthracene (sublimation flakes) has been studied as a function of the wavelength of the incident light as well as the geometry of the "surface cell" arrangement. With spot electrodes on one face of the crystal, the spectral response showed a very pronounced difference depending on whether the electrode face or the opposite face was illuminated. In the latter case the spectral response followed the absorption curve of the crystal, whereas when the electrode face was illuminated the photoconductivity was a minimum at wavelengths corresponding to maximum extinction coefficients of the crystal.

ISSN:0008-4042    

DOI:10.1139/v58-237

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

The primary quantum yield of ketene decomposition was studied as a function of pressure, temperature, and wavelength. The results show that excited vibronic states are formed which may be degraded before dissociation can occur. The ratio of the rate of collisional degradation to the rate of dissociation decreases from 164 liters/mole at 3340 Å to 16.8 liters/mole at 3130 Å.

ISSN:0008-4042    

DOI:10.1139/v58-238

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

The solubility of uranium peroxide UO4•2H2O was measured in NaOH and HClO4solutions. Possible reactions of UO4•XH2O in dilute HClO4solutions and possible reaction of UO4•XH2O in dilute NaOH solutions are indicated along with the calculated constants. As might be expected, the several oxygens associated with the uranium atom appear to make the hydroxide more acidic than basic.

ISSN:0008-4042    

DOI:10.1139/v58-239

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

Periodate lignin was sulphonated in stages by a series of short bisulphite cooks. At each stage the soluble ligninsulphonate was removed and purified, and the residue was resulphonated. The 14 fractions thus obtained had constant methoxyl content and ultraviolet absorption coefficients. There was a gradual increase in the sulphur content as the integral reaction time increased, but 26% of the ligninsulphonate possessed a sulphur content of less than 3%. There was a marked increase in both the intrinsic viscosity and rate of solution with increase in reaction time. The mechanism of the sulphonation reaction is discussed in the light of these results.

ISSN:0008-4042    

DOI:10.1139/v58-240

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

Using a Ag/AgCl (KCl–NaCl) reference electrode, the standard electrode potentials of the systems Sn/SnCl2(KCl–NaCl), Fe/FeCl2(KCl–NaCl), and Mn/MnCl2(KCl–NaCl) were determined at 700 °C and found to be 0.370 v, 0.520 v, and 1.205 v respectively. In each of the systems the Nernst equation was found to be applicable over the range of concentrations investigated.The effect of temperature on the electromotive forces of the above cells was measured and the heats of the cell reactions were calculated from the data.

ISSN:0008-4042    

DOI:10.1139/v58-241

出版商:NRC Research Press    

年代:1958

数据来源: NRC

摘要:

Photooxidation of butenes by nitrogen dioxide at room temperature has been studied at three different wave lengths: 2288, 2537, and 3261 Å. In the case of butene-1 an abrupt change in the ratios of reaction products is observed between 2537 and 2288 Å: about three times as much α-butene oxide asn-butyraldehyde is formed at 2288 Å, while the amounts of these two compounds are almost equal at the longer wave lengths. This discontinuity is ascribed to a difference in the mechanism of reaction with olefinic double bonds of the first excited state, O(1D), and the ground state, O(3P), of oxygen atoms. Experimental evidence indicates that there is collisional quenching of O(1D) to O(3P) atoms.Reactions ofcis- andtrans-butene-2 and of isobutene are much less reproducible, particularly so that of isobutene, because of the much more readily occurring thermal reaction of the excess nitrogen dioxide present with the epoxides initially formed.

ISSN:0008-4042    

DOI:10.1139/v58-242

出版商:NRC Research Press    

年代:1958

数据来源: NRC