Extraction distribution of microamounts of cesium in the two-phase water-HCl-nitrobenzene-dibenzo-18-crown-6-hydrogen dicarbollylcobaltate system

Summary Extraction distribution of microamounts of cesium in the water-HCl-nitrobenzene-dibenzo-18-crown-6(L)-hydrogen dicarbollylcobaltate has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, CsL⁺and CsL_2,⁺are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Extraction of microamounts of strontium by a nitrobenzene solution of bis-1,2-dicarbollylcobaltate in the presence of 15-crown-5

Extraction of⁸⁵Sr by a nitrobenzene solution of bis-1,2-dicarbollylcobaltate in the presence of 15-crown-5 (15C5, L) has been investigated. The equilibrium data and the typical maxima concerning the dependencies of the Sr distribution ratios on the analytical concentration of 15C5 in the system under study can be explained assuming that the HL⁺, HL₂ ⁺ and SrL₂ ²⁺ species are extracted into the nitrobenzene phase. The values of the corresponding extraction and stability constants of the extracted species in nitrobenzene saturated with water have been determined.     

Extraction of cesium from water into nitrobenzene using hydrogen dicarbollylcobaltate in the presence of p-nonylphenylnonaethylene glycol

The extraction of cesium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B^-) in the presence of Slovafol 909 (p-nonylphenylnonaethylene glycol, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, HL₂ ⁺, CsL⁺ and CsL₂ ⁺ are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Extraction of cesium into nitrobenzene using hydrogen dicarbollylcobaitate in the presence of dibenzo-24-crown-8

Extraction of microamounts of cesium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻) in the presence of dibenzo-24-crown-8 (DB24C8,L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺ and CsL⁺ are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Sequence selective recognition in the minor groove of dsDNA by pyrrole,imidazole-substituted bis-benzimidazole conjugates

A series of pyrrole, imidazole-substituted bis-benzimidazole conjugates, Py-Py-Im-gamma-biBenz, Py-Py-gamma-biBenz, Py-Im-gamma-biBenz, and Im-Py-gamma-biBenz (1-4), were prepared in an attempt to target dsDNA sequences possessing both A/T and G/C bps. The dsDNA interactions and sequence specificity of the conjugates have been characterized via spectrofluorometric titrations and thermal melting studies. All conjugates form 1:1 complexes with dsDNA at subnanomolar concentrations. The Im moiety selectively recognizes a G/C bp embedded in the A/T-rich binding site. This represents the first clear example of sequence selective recognition in a 1:1 motif.(1) The equilibrium association constant (K(1)) for complexation of a specific nine-bp dsDNA site, 5'-gcggTATGAAATTcgacg-3', by conjugate 1 is approximately 2.6 x 10(9) M(-1). Displacement of the G/C position or G/C-->A/T substitution within the nine-bp site decreases the K(1) by approximately 8-fold, whereas two continuous G/C bps decrease the K(1) by approximately 50-fold magnitude. The K(1) values for seven-bp dsDNA, 5'-gcggtaTGAAATTcgacg-3' and 5'-gcggtaCAAAATTcgacg-3', binding sites by conjugates Py-Im-gamma-biBenz (3) and Im-Py-gamma-biBenz (4) are approximately 2.3 x 10(9) and approximately 1.2 x 10(9) M(-1), respectively. However, the conjugates with no Im moiety, Py-Py-gamma-biBenz (2) and Py-Py-Py-gamma-biBenz (5 and 6), are specific for seven- to nine-bp A/T-rich sites and single A/T-->G/C bp substitution within the binding site decreases the K(1) values by 1-2 orders of magnitude.     

Sorptivity approximations

Approximate expressions of sorptivity have been tested against the Philip's numerical solution for porous materials with a wide range of parameters used in an exponential function of the water diffusivityD versus water content. The Philip-Knight approximation offers the best result when the flux ratio is approximated by the function derived for a constant value ofD.     

Eindimensionale Probleme bei einem nichtlinearen Elastizitätsgesetz

Summary Using a general nonlinear elasticity law for small strain, solutions of some elastomechanic problems are stated depending on only one coordinate. If Cartesian coordinates are applied, the equations of the simple tensile test are immediately given, by which the two arbitrary functions of the nonlinear elasticity law can easily be determined. In cylindrical and polar coordinates, the stresses are calculated in thick tubes and thick hollow spheres subjected to a uniform internal pressure. Numerical examples demonstrate a considerable deviation of stress distribution from linear theory, especially at the boundary, so that the decrease of stress maximum known in technical practice can be explained by small deviations from linearity.     

Extraction of microamounts of strontium into nitrobenzene by using hydrogen dicarbollylcobaltate in the presence of dicyclohexyl-18-crown-6

Summary Extraction of microamounts of strontium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B^-) in the presence of dicyclohexyl-18-crown-6 (DCH18C6, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, HL, SrL²⁺and SrL are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Reine ebene Biegung bei einem nichtlinearen Elastizitätsgesetz

Ohne Zusammenfassung     

Tension–compression asymmetry of phosphor bronze for electronic parts and its effect on bending behavior

In-plane tension and compression experiments on copper alloy sheets (phosphor bronze) and 6000 series aluminum alloy sheets (AA6016-T4) were conducted using a specially designed testing apparatus. The apparatus is equipped with comb-type dies so that stress–strain curves of a sheet specimen subjected to tension followed by compression, and vice versa, can be measured without buckling of the specimen, as well as those for monotonic tension and compression. A difference was observed in the flow stresses between tension and compression for the as-received copper alloy, but not for the aluminum alloy. Moreover, stress reversal tests, such as tension followed by compression and compression followed by tension, were carried out in order to measure the Bauschinger effect. In the second part of the experiment, bending moment–curvature diagrams were measured for the as-received and pre-stretched specimens. The bending moment–curvature diagrams were compared with those calculated using the stress–strain curves obtained from the tension–compression tests, and were in good agreement with those calculated with the tension–compression asymmetry and the Bauschinger effect correctly reproduced.