Supramolecular Science最新文献

A nonradioactive probe was utilized in dot-blot hybridization for the detection of infectious Epstein-Barr virus. A polymerase chain reaction PCR-generated oligonucleotide, a 121 bp segment was labeled with digoxigenin (DIG)-11-dUTP. The hybridization results were detected by using an alkaline phosphatase-conjugated antibody to DIG and the enzyme substrates. The DIG-EB DNA allowed the detection limit in 0.1 pg of DNA. The samples from fifteen patients with nasopharyneal cancer (NPC) were examined.

Effect of trivalent elements on the thermal and hydrothermal stability of MCM-41 mesoporous molecular sieve materials has been investigated. Al(III) decreases the thermal and hydrothermal stability of MCM-41 materials, whereas La(III) and Fe(III), especially Fe(III), can improve the thermal and hydrothermal stability. Benzene adsorption and IR spectra suggested that thick channel wall and the fewer structural defect sites in MCM-41 would enhance the thermal and hydrothermal stability of MCM-41.

The reversed micelles of CdS nanoparticles capped with oligomer–polymaleic acid octadecanol ester (PMAO) were synthesized by a colloid chemical method in an aqueous system. The chemical ratio of PMAO between the carboxylic group and the hydrocarbon chain was controlled to 1.5 : 1. The PMAO-capped CdS nanoparticles were transferred on to CaF₂ and Si substrates by the Langmuir–Blodgett (LB) technique. Surface pressure–area isotherms indicated that PMAO-capped CdS nanoparticles could form a stable monolayer on the water subphase. The measurement of FTIR and small angle X-ray diffraction showed that the reversed micelles of PMAO-capped CdS nanoparticles were formed with a uniform size and order in LB films. The photoluminescence properties of PMAO-capped CdS both in the solution and in the LB film indicated that the photoluminescence peaks of reversed micelles obviously changed as a result of the energy transfer from PMAO to CdS and the interaction between clusters.

The use of an electroneutral ligand modified the Cd²⁺-rich surface of CdS leads to the surrounding of CdS/2,2′-bpy by the counter ion (anion) to balance the charge of the Cd²⁺ ions, resulting in the CdS cluster with strong electrolyte behavior.

An octadecanethiol monolayer was formed on an aqueous gold sols subphase, it’s LB films were characterized by means of π-A isotherms, TEM (transmission electron microscopy), XRD (X-ray diffraction) and UV–Vis spectroscopy.

A series of dithiolene nickel complex compounds with a general formula (RCSCSR′)₂Ni that have an intense absorption band in near-IR region were successfully synthesized and the maximum IR absorption wavelengths of these dyes vary from 875 to 1495 nm in different solvents. Their characteristics of Q-switching and mode-locking for different lasers were investigated. Q-switched 1064 and 1079 nm laser with a polymer film or organic solution work satisfactorily and the pulse widths are 4–10 ns. The dyes in a variety of solutions show excellent properties in mode-locking the 1079 nm laser, particularly in mode-locking the 1340 nm laser. The pulse widths are 90–120 ps. The experimental results show that the choice of different ring substitutes and solvents will greatly influence the corresponding dye laser properties. It is also implied that BDN16 and BDN17 as the mode-locking dyes for the 1500 nm laser are satisfactory.

A series of amphiphilic complexes of N-octadecyl-8-hydroxy-2-quinoline carboxamide, M(HO)₂ (M=Mg, Ca, Mn, Ni, Zn, Pb), form a stable monolayer on a pure water subphase and can be easily fabricated as fairly stable uniform LB films. Absorption spectra and low-angle X-ray diffraction measurements showed that these LB films had good homogeneity and were Y-type bilayer films. From the position of the Bragg peaks, a thickness of ca. 5.38∼5.63 nm per bilayer were obtained. X-ray photoelectron spectroscopy analysis reveals a M : C : N ratio in the LB films consistent with the M(HO)₂ on stoichiometry. These LB films exhibit intense fluorescence and may be used as emitting material of electroluminescent devices.

Highly conductive polycrystalline and amorphous Tl₂O₃ films are prepared by electrodeposition method. The resistivity of the polycrystalline film is lower than that of the amorphous one. A resisitivity of only 3.2×10^-4 Ω cm was obtained for the polycrystalline film. It is found that the electrodeposited Tl₂O₃ films exhibit photoelectric response of n-type semiconductors. This photoelectric response may find use for further application of the Tl₂O₃ films.

Gas-sensing properties of Europium bisphthalocyanine LB films for NH₃, $\text{NO}{}_{\mathrm{x}}\text{(x=1,}\text{2)}$ and Cl₂ were investigated. No responses were observed when EuPc^′₂ LB films were exposed to 50 ppm NH₃ and $\text{NO}{}_{\mathrm{x}}\text{(x=1,}\text{2)}$, respectively. EuPc^′₂ LB films were found to produce a very fast response when exposed to Cl₂, even at the 2 ppm level. At low-concentration levels (up to ∼80 ppm), the conductivity changes linearly with the concentrations of Cl₂. The electronic spectroscopic characterization of the LB films is also given.

The Langmuir–Blodgett (LB) films built from the mixture of an amphiphilic push–pull ferrocene derivative (P) and behenic acid were investigated. Langmuir films of P diluted by behenic acid exhibit a very good cohesion and the mixed films can easily be transferred onto solid substrates. Linear dichroism UV-visible and IR spectroscopy measurements of the mixed LB multilayers confirm that the molecules (P) are oriented to the substrate. The nonlinear optical experiments on the mixed monolayer deposited on the CaF₂ slide showed that P displayed efficient optical second harmonic generation (SHG) with a molecular hyperpolarizability (β) as high as 6.0×10^-29 e.s.u.