Hydrophilic-lipophilic balance and surface film state of nonionic surfactants

Summary The polarographic study on the effect of nonionic surfactants on the damping of oxygen maximum confirms the validity ofVan Voorst Vader's rule and a major part which play the hydrophilic-lipophilic balance of surfactant molecules in surface phenomena. On this basis the simple relationships are presented between the molecular area in surface film (A) andGriffin's andDavies' HLB. It is shown that at a specific pressure theA increases with increasing HLB values for homologous series of nonionic surfactants. The limitations of the validity of the relations derived with respect to the specific surface pressure chosen are also considered.

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Zusammenfassung Polarographische Studien über die Wirkung nichtionogener Tenside auf die Dämpfung des Sauerstoff maximums bestätigen die Gültigkeit der Regel vonVan Voorst Vader und den überwiegenden Einfluß, welchen der Anteil hydrophil-lipophil in den Tensidmolekülen für Grenzflächenphänomene spielt. Auf dieser Basis wird eine einfache Beziehung erhalten zwischen dem Flächenbedarf eines Moleküls im Grenzflächenfilm (A) undGriffin's undDavies HLB-Werten. Es wird gezeigt, daß bei einem spezifischen Oberflächendruck dieA-Werte mit steigenden HLB-Werten in homologen Reihen nichtionogener Tenside ansteigen. Die Grenzen der Gültigkeit dieser Regel werden diskutiert.

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With 2 tables     

The decay of theT=1 isospin triplet inA=12 systems: II. The induced interactions in the anisotropy of beta-rays

Nuclear Structure: calculation of the asymmetryα _? ofβ rays emitted from polarized¹²B and¹²N nuclei. Comparison with experimental values. Formulae for the asymmetry parametersα _? ofβ rays emitted from polarized nuclei is derived using the formalism developed by Behrens-Bühring. The induced interactions are studied in detail. It is demonstrated that the expressions forα _? are independent of the induced pseudoscalar interaction. It was found that the corrections to the lowest order approximation are small. Experimental data of the Louvain and Osaka laboratories are analyzed. We should point out that the data of the asymmetry of theβ ^? decay of¹²B obtained in these two laboratories are quite different. Although the data reported by the Osaka Group require the existence of the induced pseudotensor (IPT) interaction as it has also been stated by other authors, if we combine data of¹²N from Osaka and of¹²B from Lauvain such experimental results can be understood without including the IPT interaction. Thus, we found some evidence that the IPT interaction could be not necessary to explain the asymmetries in the decay of members of theA=12 system.     

Induced scalar interaction in the analysis of superallowed fermi β transitions

Nuclear Structure superallowed Fermiβ transitions; derivation of the coupling constant for the induced scalar interactionf _s from experimental data. Very recent works reported a significant improvement in the consistency of ?t values for superallowed Fermiβ-decays. This fact led us to investigate some aspects which are not usually tackled in a study of this kind of transition. In a recent paper we suggested that an upper limit for the coupling constantf _s for the induced scalar interaction can be derived analyzing superallowed Fermiβ-transitions. In the present work we revise and improve the method for the determination off _s . The result obtained,f _s /f _v =(? 0.4±1.4) × 10^?3, agrees with the prediction of the CVC theory.     

Ultrahigh modulus polyethylene. II. Effect of drawing temperature on void formation and modulus

The maximum degree of molecular orientation and deformation obtained by ultradrawing of high-density polyethylene in air is limited by formation of internal voids (both longitudinal separation of fibrils and perpendicular cracking), and thus values of Young's moduli which are achievable by ultradrawing techniques are also limited to values much below the theoretical limit for fully extended chains. Temperature has a significant effect on the critical draw ratios at which intensive void formation begins, and also on the draw ratio at which failure occurs during the ultradrawing. The temperature effect is observed only for high-density polyethylene having a wide molecular-weight distribution, and which can be drawn at higher temperatures (30–40°C below its melting point), e.g., Dow Chemical polyethylene LP51.1. As a result of ultradrawing at higher temperatures, transparent, ultrahigh modulus samples having draw ratios of order of 40 have been obtained. The higher drawing temperatures significantly reduce fibril separation, and perpendicular cracking is shifted toward higher draw ratios. Hence, with LP51.1 the highest Young's moduli (65–70 GPa) have been exhibited by the samples which were ultradrawn at 100–105°C.     

The field-induced states at the surfaces of the nearly-free-electron metals

We have studied theoretically the energy spectra of the field-induced electronic states, generated by the positive external electric field applied to the Au(001) and Au(111) surfaces. The aim of this paper was to investigate the influence of the Schockley-inverted energy gap in the metal band structure on the energies of these states. The investigations have been performed for different intensitiesF of the applied electric field (0<F}<10⁸ V/cm). Our results indicate that the crystal potential influences considerably the energy spectra of the field-induced states. This effect is especially important in the case where these states appear near the energy gap.     

Extended convergence to continuous in probability processes with independent increments

Summary A special (extended) kind of convergence in distribution of processes with filtration is considered. Recent theorems on the functional convergence of semimartingales are improved by showing that their assumptions imply the extended convergence of semimartingales to continuous in probability processes with independent increments.     

Transannular interactions insyn- andanti- [2.2](1,4) napthalenophanes andsyn- andanti- [2.2](1,4) anthracenophanes

The UV spectra of the title compounds were interpreted as a result ofPPP-CI-1 calculations of excitation energies and oscillator strengths for the singlet—singlet transitions. A good agreement of the theoretical transitions with the experimental spectrum was found. A strong transannular effect was characteristic for thesyn isomers, the effect decreased in the order:syn-ring anthracenophane,syn-ring naphtalenophane,anti-ring naphthalenophane,anti-ring anthracenophane. Also the influence of a pseudo-substituent effect was found and discussed.