An improved calculation for the inner-shell ionization problems

A calculation for the inner-shell ionization problems is made in a new approach. Results are compared with measured values for doubly and triply differential cross sections and improvements are noticed.     

Electrical and magnetic properties of antimony sulphide (Sb2S3) crystals and the mechanism of carrier transport in it

The principal magnetic susceptibilities, electrical conductivities and thermoelectric powers of Sb₂S₃ single crystals have been studied in the temperature range 100–550 K. An analysis of the results on the basis of its anomalous crystal structure and of the proposition of the hopping process of conduction at higher temperatures, account for the discrepancy between findings from magnetic and electrical observations.     

Mechanisms of antioxidant action: Stabilisation of polypropylene during processing and on exposure to light

The most important initiators for the photo-oxidation of processed polypropylene are thermally formed hydroperoxides. Peroxide decomposing antioxidants (ZnDEC and NiDEC) effectively control hydroperoxide formation, and hence oxidation, during processing. A chain breaking antioxidant (1076) is effective and a typical uv absorber (HOBP) completely ineffective. The uv stabilising activity of these compounds is NiDEC > HOBP > 1076 > ZnDEC; the first two show a strong concentration dependence whereas the last two do not. The two dithiocarbamates are relatively more effective at high temperatures and they synergise effectively with the uv absorber. The synergism obtained with ZnDEC is higher than that with NiDEC.     

Binding energy of finite nuclei in Jastrow-Factor-Cluster method with applications in helium

A general expression for the binding energy of finite nuclei in the Jastrow-Factor-Cluster method is developed upto the three-body cluster term with centre of mass correction. It is applied in massA=3 and 4 with the standard Chakkalakal function and the average Pauli condition. Compared to the previous work of Afnan (1969) better saturation properties are obtained for two- and three-body truncation. Convergence is also better.     

Application of dye-partition technique to the determination of the rates of initiation in radical polymerization

Summary Dye-partition technique as an useful method of measuring kinetic chain length (v), rate of initiation (R _i ), initiator efficiency (f), and the parameter [=(2k _t)^1/2 k _p] etc. in radical polymerization using styrene and methylmethacrylate as monomers in dimethyl formamide medium and 4,4 azobis-4-cyanopentanoic acid as the initiator to produce dye responsive carboxyl ended polymers has been discussed. The values ofR _p,f and obtained by this method compare fairly well with those obtained by a standard method, viz., molecular weight method. The magnitude off much less than unity and constancy in its value under different concentrations of monomers and initiator indicate that almost all radicals surviving geminate recombination is captured by the monomers. The precautions necessary for applying this method have also been discussed.

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Zusammenfassung Farbstoff-Verteilungstechnik als nützliche Methode zur Messung der kinetischen Kettenlänge (v), Initiationsgeschwindigkeit (R _i ), des Initiator-Wirkungsgrades (f), und des Kennwertes (2k,^1/2 k _p ) (=) etc. bei der radikalischen Polymerisation von Styrol und Methylmethacrylat in Dimethylformamid-Medium mit 4,4'-Azobis-4-cyanopentansäure als Initiator zur Bildung von mit Farbstoffen reagierenden Carboxylatendgruppen in den Polymeren, wurde diskutiert. Die durch obengenannte Methode festgestellten Werte vonR _p ),f und sind ungefähr mit den durch übliche Methoden festgestellten Werten vergleichbar (durch Molekulargewicht-Methode).Die konstante Größenordnung von 'f, die viel weniger als eins beträgt, weist darauf hin, daß alle die paarweise Rekombination überlebenden Radikale von den Monomeren abgefangen werden. Die zur Anwendung dieser Methode nötigen Vorsichtsmaßnahmen sind auch diskutiert worden.

     

The influence of ultrasonic waves on the hydrogen ion concentration and the stability of colloidal solutions

Summary The ultrasonic waves causes the cerie hydroxide sol to set to a gel. This change has been followed by measuring viscosity, conductivity and hydrogen ion concentration. It has been shown that the extent of hydrogen peroxide formed under the action of ultrasonic waves on water is not alone sufficient to explain for the increase in viscosity, nor at such concentrations it would set the sol to a gel.

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Zusammenfassung Ultraschall verursacht in Cerhydroxyd-Solen Gelierung. Dieses Ver?nderung wurde durch Messen der Viskosit?t, Leitf?higkeit und der Wasserstoffkonzentration verfolgt. Es hat sich gezeigt, da? der Betrag an Wasserstoffperoxydbildung unter Einwirkung des Ultraschalles auf Wasser nicht allein ausreichend ist, den Anstieg in der Viskosit?t oder hinsichtlich der Konzentration zu erkl?ren, um die Gelierung zu deuten.

     

Exponents of class groups of real quadratic function fields (II)

Let be an even positive integer. We show that there are polynomials with such that the ideal class group of the real quadratic extensions have an element of order .

     

Exploration of the secondary structure specific differential solvation dynamics between the native and molten globule states of the protein HP-36

Recent experiments have shown that the time dependence of fluorescence Stokes shift of a chromophore is substantially different when the chromophore is located in a molten globule (MG) state and in the native state of the same protein. To understand the origin of this difference, particularly the role of water in the differential solvation of the protein in the native and the MG states, we have carried out fully atomistic molecular dynamics simulations with explicit water of a partially unfolded MG state of the protein HP-36 and compared the results with the solvation dynamics of the protein in the folded native state. It is observed that the polar solvation dynamics of the three helical segments of the protein is influenced in a nonuniform heterogeneous manner in the MG state. While the equilibrium solvation time correlation function for helix-3 has been found to relax faster in the MG state as compared to that in the native state, the decay of the corresponding function for the other two helices slows down in the MG state. A careful analysis shows that the origin of such heterogeneous relative solvation behavior lies in the differential location of the polar probe residues and their exposure to bulk solvent. We find a significant negative cross-correlation between the contribution (to the solvation energy of a tagged amino acid residue) of water and the other groups of the protein, indicating a competing role in solvation. The sensitivity of solvation dynamics to the secondary structure and the immediate environment can be used to discriminate the partially unfolded and folded states. These results therefore should be useful in explaining recent solvation dynamics experiments on native and MG states of proteins.