The structure of CdS nanoparticles

CdS nanoparticles in the high-pressure polyethylene (HPPE) matrix have been synthesized and investigated. Shift of the fundamental absorption edge has been shown to be absent with a variation in the nanoparticle size for the given samples and a small disordering of atoms in nanoparticles is observed.     

Andrei Yurievich Khrennikov and his Research

This paper contains a brief review of a very diverse and vast scientific work of Andrei Yurievich Khrennikov on the occasion of his 60th birthday.     

Complexation of pyrene and anthracene with human blood plasma

We have studied the interaction between polycyclic aromatic hydrocarbons (pyrene and anthracene) with human serum albumin (HSA) and human blood plasma. We have shown that the increase in the fluorescence intensity and the decrease in the polarity index of pyrene on going from an aqueous solution to a pH 7.4 buffer solution of HSA suggests that polycyclic aromatic hydrocarbons are localized in the hydrophobic microphase of the proteins. The increase in the fluorescence intensity for anthracene and pyrene, and also the decrease in the polarity index of pyrene on going from HSA to blood plasma is connected with the fact that polycyclic aromatic hydrocarbons can bind both to plasma proteins and to plasma lipids. When sodium dodecyl sulfate (SDS) is added to the blood plasma in a concentration greater than the critical micelle concentration, we observe an increase in the fluorescence intensity and the polarity index of pyrene. We hypothesize that this is connected with localization of pyrene near the interface between the hydrophobic and hydrophilic phases of the protein-SDS system. We have established that SDS leads to a change in the structure of blood plasma proteins and promotes escape of polycyclic aromatic hydrocarbons from the protein globules. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 3, pp. 379–382, May–June, 2008.     

TDDFT studies of electronic structure and first hyperpolarizability of terta-nuclear cubane-like transition metal clusters

The TDDFT method is first applied in a series of tetra-nuclear transition metal clusters studies for nonlinear optical properties. The results indicate that the charge transfer inside the metal core [MCu3X4] (M=W, Mo; X=S, O, Cl, Se, Br) makes contribution to the optical nonlinearity. It is possible to enhance the hyperpolarizability by substituting the ligands of the clusters.     

On the Intermittency in Nuclear Fragmentations

A simple Monte Carlo simulation and even a partition method can be used to reproduce quite well the power law behavior between the factorial moment and the charge interval of fragment charge distributions from the multifragmentation of ¹⁹⁷Au nucleus bombarding emulsion at～1 GeV/nucleon. This indicates that the above power law seems not to be a unique precursor of the intermittent behavior in nuclear multifragmentations.     

NUCLEAR CHARGE DISPERSION OF FRAGMENTS IN HIGH ENERGY PROTON-NUCLEUS COLLISION

The charge dispersion of fragments in high energy p+Cu,Kr and Xe reactions are calculated by statistical model and Monte Carlo technique.The corresponding data are reproduced quite well.It is shown that the charge dispersions are all nearly gaussian.The mass dependence of the most probable fragment charge reflects the rest target memory effect.     

EQUATION OF STATE OF HOT NUCLEI BEFORE BREAK-UP

Following the method developed by the authors,recently,the equation of state of hot nuclei(²³⁸U in concrete) before break-up was investigated numerically.The isotherms are drawn in the plan of the general pressure P versus volume V_RT. They are similar to those of Van der Waals gas.The critical temperature of phase transition should correspond to the isotherm with one turning point only.It turns out that the data of mass yield distribution can be reproduced by many pairs of parameters T and V_RT (freeze-out temperature and freeze-out volume) varying in certain range.For each isotherm (each T),the data are always best reproduced by the value of V_RT located at the maximum general pressure within two phases coexistence region.     

Λ Production and Λ/p Ratio in Relativistic Heavy Ion Collisions

The Λ multiplicity and Λ/p ratio are studied by hadron transportation-string fragmentation model in relativistic heavy ion collisions. Firstly, the dependence of Λ multiplicity and Λ/p ratio on the system size and the collision centrality is studied. It shows that the Λ and p multiplicities go up as the increase of system size and the increase of collision centrality. However, their ratio keeps almost a constant. The effect of Λ annihilation cross section to Λ multiplicity and Λ/p ratio is also studied. It is found that this effect is weak: Λ multiplicity and Λ/p ratio have a little amount of increase by the decrease of Λ annihilation cross section. Even the cross section is down to zero, Λ/p ratio is only 1.2 in 200A GeV AuAu head on collision. The Λ/p ratio is obtained to be 0.28 in pp collision, lying in the range of experimental data:0.2—0.3. It is also obtained that the ratio in AA collisions is 3—5 times of that in pp collision.     

Scientific Bases for the Synthesis of Highly Dispersed Framework Zirconium Phosphate Catalysts for Paraffin Isomerization and Selective Oxidation

Results of the systematic study of the synthesis of highly dispersed framework zirconium phosphates stabilized by ammonium, lanthanum, aluminum, manganese, and cobalt cations are summarized. The synthesis involves the mechanochemical activation of a mixture of solid reactants (salts) or the sol–gel process each followed by the hydrothermal treatment (HTT) of obtained precursors in the presence of surfactants. The genesis of dispersed systems under investigation is studied by modern physical methods providing information on the state of the bulk and surface of the systems. It is found that the local structure of sol nanoparticles and zirconium phosphate crystalline nuclei arising from mechanochemical activation products depends on the nature of initial substances. This, in its turn, makes different crystallization mechanisms possible during the HTT process: the dissolution/precipitation mechanism or the mechanism of oriented mating of primary particles. The crystallization mechanism in HTT and the reaction system composition influence the nature of resulting complex zirconium phosphate phases, their thermal stability, dispersity, and porous structure parameters. The relationship between the bulk structure parameters of framework zirconium phosphates, which are controlled by varying the chemical composition and conditions of synthesis, and the surface characteristics of the systems (the strength and concentration of different Lewis and Br@nsted sites) is studied. It is shown that systems based on framework zirconium phosphates are promising catalysts for paraffin (pentane and hexane) isomerization, the selective oxidation of methane by oxygen into synthesis gas at short contact times, and the oxidative dehydrogenation of propane into propylene.