Assembly and disassembly of a Zn10 high-nuclearity circular helicate

A nano-scale decanuclear Zn(II) circular helicate is synthesized without the aid of counteranions during the assembly process, and can be totally disassembled into its reactants by specific anions.     

An error minimized pseudospectral penalty direct Poisson solver

This paper presents a direct Poisson solver based on an error minimized Chebyshev pseudospectral penalty formulation for problems defined on rectangular domains. In this study the penalty parameters are determined analytically such that the discrete L₂ error is minimized. Numerical experiments are conducted and the results show that the penalty scheme computes numerical solutions with better accuracy, compared to the traditional approach with boundary conditions enforced strongly.     

Ion-implanted treatment of (Ba,Sr)TiO3 films for DRAM applications

The effects of ion implantation on the properties of spin-on sol–gel Ba_0.7Sr_0.3TiO₃ (BST) thin films were studied by implanted Ar⁺, N⁺, and F⁺ doses. The F⁺-implanted BST samples present leakage current density <10⁻⁶ A/cm² at 2.5 V and dielectric constant 450. The leakage current of F⁺-implanted BST samples was reduced about one order of magnitude as compared with that of samples with implanted Ar⁺, N⁺ or without implantation. The thickness shrinkage from 135 to 115 nm was observed in F⁺-implanted BST films (before annealing treatment) and a respective increase in the refractive index from 1.84 to 2.05 was measured. After annealing the implanted samples, the changes of thickness and refractive index depend on the concentration of implanted dose. Based on an infrared transmission study of the samples we suggest that the ion-implanted samples with smaller dose (5×10¹⁴ cm⁻²) have fewer −OH contaminants than the non-implanted or implanted samples with the larger doses (1×10¹⁵ cm⁻²). Based on the results presented, we conclude that suitable ion implantation densifies the spin-on sol–gel BST films and reduces the −OH contaminants in the films.     

Mach–Zehnder interferometer by utilizing phase modulation of transmitted light through magnetic fluid films possessing tunable refractive index

Due to its diverse applications in photonics, bio-sensors, mechanics, etc., Mach–Zehnder interferometer becomes one of important devices. Hence, lots of efforts have been paid to develop advanced Mach–Zehnder interferometers. In this work, we explore new-model Mach–Zehnder interferometer, in which one of arm is consisted of magnetic fluid films. By utilizing the tunable refractive index of magnetic fluid films under external magnetic fields, the traveling phase of a propagating light through the magnetic fluid film is changed. This could lead to a variation in the interfered intensity of the Mach–Zehnder interferometer when an external magnetic field is applied. The modulation in the interfered intensity by the external magnetic field is demonstrated experimentally, and the relevant physical origin is also discussed.     

Metabolites with Cytotoxic Activity from the Formosan Soft Coral Cladiella Australis

The metabolites, (24S)‐3β‐acetoxyergost‐5‐en‐21‐oic acid ( 2 ), 5′‐O‐acetylthymidine ( 3 ), 3′‐O‐acetylthymidine ( 4 ), and p‐vinylbenzyl alcohol ( 5 ), along with a known steroid ( 1 ) were isolated from the EtOAc extract of the Formosan soft coral Caldiella australis. The structures of new metabolites were determined on the basis of spectroscopic (including 1D and 2D NMR) analyses and by comparison of their NMR spectral data with those of related compounds. Except for 3 , all compounds exhibited cytotoxic activity of various degrees of potency against a limited panel of human liver and breast cancer cell lines.