One-pot synthesis of ZnS/polymer composites in supercritical CO2-ethanol solution and their applications in degradation of dyes

A facile method to decorate the polymeric hollow spheres with ZnS nanoparticles has been presented. In this method, the precursors, Zn(Ac)(2)H(2)O and CH(3)CSNH(2), were first adsorbed by the polymer substrate in supercritical CO(2)-ethanol solution at 35 degrees C. Followed by heating the mixture at 100 degrees C for 2 h, ZnS/polymer composites were obtained. The as-produced ZnS/polymer composites were characterized by means of IR spectra, X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy. It was demonstrated that crystalline ZnS nanoparticles with size of 3-5 nm were uniformly decorated on the polymer spheres under suitable conditions. The resultant ZnS/polymer composites exhibited high efficiency for degrading eosin B, methyl orange and methylene blue under UV light irradiation.     

Mapping molecular conformations with multiple-mode two-dimensional infrared spectroscopy

The multiple-mode two-dimensional infrared (2D-IR) spectrum in a broad frequency range from 1000 to 3200 cm(-1) of a 1-cyanovinyl acetate solution in CCl(4) is reported. By analyzing its relative orientations of the transition dipole moments of normal modes that cover vibrations of all chemical bonds, the three-dimensional molecular conformations and their population distributions of 1-cyanovinyl acetate are obtained, with the aid of quantum chemistry calculations that translate the experimental transition dipole moment cross angles into the cross angles among chemical bonds.     

Particle-wire-tube mechanism for carbon nanotube evolution

The synthesis of carbon nanotubes (CNTs) has been proved to be greatly promoted by vapor metal catalysts, but the fast reaction feature and the required high-temperature environment involved in CNT evolution usually make it difficult for an insight into the evolution mechanism. Here, we successfully freeze the synthetic reaction at intermediary stages and observe the detailed morphologies and structures of the obtained intermediates and various objects related to carbon nanotubes. It is unveiled that there is a kindred evolution linkage among carbon nanoparticles, nanowires, and nanotubes in the vapor catalyst-involved synthetic processes: tiny carbon nanoparticles first form from a condensation of gaseous carbon species and then self-assemble into nanowires driven by an anisotropic interaction, and the nanowires finally develop into nanotubes, as a consequence of particle coalescence and structural crystallization. The function of metals is to promote the anisotropic interactions between the nanoparticles and the structural crystallization. An annealing transformation of carbon nanoparticles into nanotubes is also achieved, which gives further evidence for the evolution mechanism.     

Extended calix[4]arene analogues by two P-CuI-P bridges and anion encapsulation

Two novel extended calix[4]arene analogues by two P-Cu(I)-P bridges have been synthesized. The molecular structures and anion encapsulation ability for ClO4- and BF4- have been studied by X-ray analysis.     

Ferroelectric metal-organic framework with a high dielectric constant

Hydrothermal reaction of (l)-N-(4'-cyanobenzy)-(S)-proline with CdCl2 as a Lewis acid catalyst and NaN3 gives colorless block compound 1, in which 1 displays a complicated 3D framework. Ferroelectric and dielectric property measurements reveal that 1 exhibits physical properties comparable to that of a typical ferroelectric compound with a dipole relaxation process and a dielectric constant of ca. 38.6 that makes it, by definition, a high dielectric material.     

Self-assembly of a diblock copolymer on a patterned surface with low-energy electron beam

A pattern was generated by 500 eV electron beam irradiation on benzaldimine monolayer through a grid and subsequent hydrolysis of nonirradiated regions. While we tried to assemble a block copolymer, polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP), on the pattern, we observed that the polarity difference between the two different regions was not right for discriminating the wetting behavior of two blocks of the polymer. Among various modifications of the retrieved amine, it was found that tribromoacetaldehyde was suitable for this end. Surprisingly, treatment of the aldehyde gave a surface preferring the polystyrene block to poly(4-vinylpyridine) block, while the irradiated section favored the latter block. As a result, island morphology was observed on the tribromoacetaldimine region and hole morphology on the irradiated region when the film thickness was 1.3Lo. Contact angle data were consistent with the observed symmetric wetting on the former region and the asymmetric one on the latter.     

Compensation for pixel-mismatch errors in shift-multiplexed holographic data storage

To read out correct data from shift-multiplexed holographic data storage, we propose a novel method of pixel matching by use of a tiny plane-parallel refraction plate placed in the path of converging readout beams. Tilting the refraction plate produces a shift in the lateral position of the readout beam incident upon the holographic storage disk, leading to compensation for pixel-mismatch errors by an improvement in bit-error rate of 3 orders of magnitude.     

Nanoscopic surface patterns of diblock copolymer thin films

The surface topography of thin diblock copolymer films is studied by atomic force microscopy (AFM). With AFM an island-to-ribbon transition is observed for symmetric polystyrene-b-poly (4-vinylpyridine) (PS-b-P4VP) on mica with increasing solution concentration. Our study also demonstrates how the formation of the pattern strongly depends on the copolymer composition based on the volume fraction. The substrate and solvent used both have great effects on the morphology of the thin films. Only by using highly polar substrate (mica), can we gain regular pattern. The reason why the regular islands cannot be obtained with symmetric PS-b-P4VP on graphite is also explained. On mica using nonselective and selective solvents, a rather regular pattern can be obtained. The difference is only in the solution concentration for forming regular patterns.     

An NMR technique for rapid measurement of flow

We present a one-scan method for determining fluid flow velocity within a few milliseconds in the presence of a static field gradient, and without the need of multiple scans. A few RF-pulses populate a series of coherence pathways, each of which exhibits a phase shift that is proportional to fluid velocity. These coherence pathways produce spin echoes separated in the time domain, thus eliminating the need for phase cycling.     

Dissipation of System and Atom in Two-Photon Jaynes–Cummings Model with Degenerate Atomic Levels

A method of perturbative expansion of master equation is employed to study the dissipative properties of system and of atom in the two-photon Jaynes–Cummings model (JCM) with degenerate atomic levels. The numerical results show that the degeneracy of atomic levels prolongs the period of entanglement between the atom and the field. The asymptotic value of atomic linear entropy is apparently increased by the degeneration. The amplitude of local entanglement and disentanglement is suppressed. The better the initial coherence property of the degenerate atom, the larger the coherence loss.