Phase behavior of binary system of bromobenzene–chlorobenzene confined in SBA-15 and MCM-41

Phase behavior of binary system of bromobenzene-chlorobenzene（C6H₅Br-C₆H₅Cl） confined in SBA-15 and MCM-41（pore diameter 8 nm,3.8 nm,respectively） has been investigated by means of differential scanning calorimetry（DSC）.Phase diagram of C₆H₅Br-C₆H₅Cl system confined in SBA-15 is a type of the complete miscible both in liquid and solid state,the same phase behavior as the bulk system.However,the phase diagram comprises only one boundary line,which is shifted down 22-36 K with respect to the bulk system.C₆H₅Br,C₆H₅Cl or the mixture within nanopores of MCM-41 is nonfreezing.The different phase behavior of the system confined in SBA-15 and MCM-41 is thought mainly due to the relative size of pore to molecule.     

Optical and IR study of CdS nanoparticles dispersed in a new confined p-phenylenevinylene

In the present study we have synthesized CdS semiconducting quantum dots by reverse micelle method using dodecanthiol (C₁₂H₂₆S) as the capping agent. The synthetic medium consists of a quaternary water/Sodium dodecyl sulfate (SDS)/buta-1-ol/hexane microemulsion. The size of the particles was controlled by changing the molar ratio W=[H₂O]/[SdS], where [H₂O] and [SdS] are the molar concentrations in hexane of water and SdS respectively. The CdS nanoparticles were embedded in a new PPV derivate named Fluorinated Bisphenol A P-phenylenevinylene (BPAF-PPV). Fourier transform infrared spectroscopy (FT-IR) showed a strong interaction of thiol groups with CdS nanoparticles. Blue shift of the optical absorption onset is observed due to quantum size effect. The band gap and particle sizes of the nanoparticles were deduced from optical absorption spectra and the use of an effective mass approximation (EMA) model. Photoluminescence spectroscopy evidenced a charge transfer process via the interface between BPAF-PPV/CdS nanoparticles.     

Two laser-driven mix experiments to study reshock and shear

In an effort to better understand mix in Inertial Confinement Fusion (ICF) implosion cores, a series of laser-driven mix experiments has been designed for the University of Rochester's OMEGA laser. Our objective is to perform experiments to investigate the turbulent mixing at material interfaces when subject to multiple shocks and reshocks or high-speed shear. Ultimately, these experiments are providing detailed quantitative measurements to assist in validation efforts for the BHR-2 mix model, which is implemented in the RAGE hydrodynamics code. The Reshock experiment studies the physical process of shocking and reshocking mix layers. Radiographs are recorded to compile a temporal evolution of the mixing layer and its subsequent reshock, compression, and re-growth phases. The Shear experiment investigates shear-driven growth of a mix layer, and radiography captures the time evolution of the development of turbulent mixing due to shear. Simulations of both the Reshock and Shear experiments using RAGE and the BHR-2 mix model demonstrate good agreement with the mix evolution seen in the experimental data, giving confidence that BHR-2 is capable of simulating the behavior of both compressive and shear-driven turbulent flows.     

Effect of confinement on the Eu emission band D0→F0 in Eu-doped nano-glass-ceramics

We report a non-linear blue shift of the zero-phonon emission line ⁵D₀→⁷F₀ of Eu³⁺-dopant in Eu³⁺-doped nano-glass-ceramics in magnetic field up to 50 T. The shift is significantly larger in nano-glass-ceramics compared to its precursor glass, suggesting that the nanoceraming of the precursor glass decreases the effective mass of the f-electrons bands of Eu³⁺ resulting in their enhanced magnetic confinement. Moreover, the non-linear character of the magnetic field dependence of this blue energy shift denotes a spatial confinement of f-electrons wave-functions of Eu³⁺ dopants in the PbF₂-based nanocrystals of the nano-glass-ceramics where up to 90% of the dopants partition. The spatial confinement seems to be due to an admixture to the f-states of Eu³⁺ of its higher lying states of opposite parity which fall in the quantum well comprising of Eu³⁺-doped PbF₂ crystalline nanoparticles embedded in the surrounding glass network.     

Dual Superconductivity in Restricted Chromo-Dynamics (RCD)

Characterizing the dyonically condensed vacuum by the presence of two massive modes (one determining how fast the perturbative vacuum around a colour source reaches the condensation and the other giving the penetration length of colored flux), it has been shown that due to the dynamical breaking of magnetic symmetry the vacuum of RCD acquires the properties similar to those of relativistic superconductor. Originally present global SU(2) symmetry in RCD has been broken to U(1) reducing the four dimensional action to two dimensional one by using an Ansatz which incorporates a non-trivial coordinate dependent phase between the components of SU(2) doublet. Analyzing the behaviour of dyons around RCD string, the solutions of classical field equations have been obtained and it has been shown that magnetic constituent of dyonic current is zero at centre of the string and also at the points far away from the string. The conditions for this current to be maximum at a transverse distance from the string have also been obtained.     

~2H-NMR CHARACTERIZATION OF CLAY DISPERSION AND CONFINEMENT EFFECT ON PROBE MOLECULES IN RUBBER/CLAY NANOCOMPOSITE-GELS

~2H-NMR spectroscopy of the probe molecule,deuterated benzene,was applied to characterize organo-clay dispersion and confinement effect on the local motion of benzene in rubber/clay nanocomposite-gels.The observed ~2H line shapes of benzene in intercalated and exfoliated nanocomposites were obviously different,which can be used to estimate clay-dispersion quality.~2H-NMR line shapes also reflect the different influence of intercalated or exfoliated layered-silicates on local motions of benzene,implying t...     

Few-body quantum method in a d-dimensional space

In this work we investigate the continuous confinement of quantum systems from three to two dimensions. Two different methods will be used and related. In the first one the confinement is achieved by putting the system under the effect of an external field. This method is conceptually simple, although, due to the presence of the external field, its numerical implementation can become rather cumbersome, especially when the system is highly confined. In the second method the external field is not used, and it simply considers the spatial dimension d as a parameter that changes continuously between the ordinary integer values. In this way the numerical effort is absorbed in a modified strength of the centrifugal barrier. Then the technique required to obtain the wave function of the confined system is precisely the same as needed in ordinary three dimensional calculations without any confinement potential. The case of a two-body system squeezed from three to two dimensions is considered, and used to provide a translation between all the quantities in the two methods. Finally we point out perspectives for applications on more particles, different spatial dimensions, and other confinement potentials.     

Silicon nano crystal filled ellipse core based quasi photonic crystal fiber with birefringence and very high nonlinearity

In this paper, we have proposed a new type of quasi photonic crystal fiber (PCF) with a silicon nano crystal core. This structure can be used to sense aqueous analysis over a wavelength range of 1.00?µm to 3.00?µm. The properties of this structure are simulated using the vector-finite element method (VFEM) employing a boundary condition. The proposed model provides a significant effect of birefringence and a very high nonlinear coefficient for two different fundamental modes, which are obtained by adjusting the size of the silicon nano crystal filled ellipse core. This provides a high nonlinearity of 4.2?×?10⁵ W^?1Km^?1 and a birefringence of ? 3.2?×?10^?1 at the wavelengths 1.00?µm and 3.00?µm, respectively. Some others properties, such as the effective area, scattering loss, confinement loss, numerical aperture (NA)and power fraction are also analyzed to measure the performance of this structure. The proposed model is useful for sensing and biomedical imaging applications. The proposed structure may also find extensive applications in optical communication and sensor systems.     

Enhanced heat transfer in confined pool boiling

We report the results of an experimental investigation of the heat transfer during nucleate boiling on a spatially confined boiling surface. The heat flux as a function of the boiling surface temperature was measured in pool boiling pots with diameters ranging from 15 mm down to 4.5 mm. It was found that a reduction of the pool diameter leads to an enhancement of the nucleate boiling heat flux for most of the boiling curve. Our experimental results indicate that this enhancement is not affected by the depth of the boiling pot, the material of the bounding wall, or the diameter of the inlet water supply. High-speed camera imaging shows that the heat transfer enhancement for the spatially confined pool boiling occurs in conjunction with a stable circulating flow, which is in contrast to the chaotic and mainly upward motion for boiling in larger pool diameters. An explanation for the enhancement of the heat transfer and the associated change in flow pattern is found in the singularisation of the nucleate boiling process.