Standard‐free composition measurements of Alx In1–xN by low‐loss electron energy loss spectroscopy

We demonstrate a standard‐free method to retrieve compositional information in Al_x In_1–xN thin films by measuring the bulk plasmon energy (E_p), employing electron energy loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM). Two series of samples were grown by magnetron sputter epitaxy (MSE) and metal organic vapor phase epitaxy (MOVPE), which together cover the full com‐ positional range 0 ≤ x ≤ 1. Complementary compositional measurements were obtained using Rutherford backscattering spectroscopy (RBS) and the lattice parameters were obtained by X‐ray diffraction (XRD). It is shown that E_p follows a linear relation with respect to composition and lattice parameter between the alloying elements from AlN to InN allowing for straightforward compositional analysis. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

On the Minimum and Maximum of Bivariate Lognormal Random Variables

Assume that (X,Y) is a bivariate lognormal vector. Let u = ln(X) and v = ln(Y). Then (u, v) is normally distributed. This note examines the effects of the distribution parameters of (u, v) on the first two moments of the order statistics of (X,Y). AMS 2000 Subject Classification Primary—62G30     

TLC plates as a convenient platform for solvent-free reactions

Solvent-free oxidative couplings of naphthols have been optimized by co-spotting catalysts and substrates directly on silica TLC plates and heating, followed by chromatography, staining, and qualitative visualization.     

Preparation and properties of conductive silver/photosensitive polyimide nanocomposites

A new electrically conductive photoresist has been developed. It is based on the dispersion of silver nanoflakes in a negative‐tone photosensitive polyimide (PSPI) precursor. 2‐Mercaptopropionic acid was used as the surfactant to modify the silver nanoflake surface for the dispersion of silver nanoflakes in the polymer. The silver/PSPI nanocomposites showed electrical conductivity at a low silver content of 10 wt %. The electrical conductivity of the silver/PSPI nanocomposites ranged from 10 to 10⁴ S/cm, which was dependent on the silver weight fraction in the resist formulation. Patterns with a resolution of 30 μm were obtained from the silver/PSPI nanocomposites. The silver/PSPI nanocomposites had excellent thermal properties. Their glass transition temperatures were above 360 °C and thermal decomposition temperatures were over 420 °C. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1575–1583, 2009     

Synthesis and properties of a new fluorine‐containing polybenzimidazole for high‐temperature fuel‐cell applications

An amorphous, organosoluble, fluorine‐containing polybenzimidazole (PBI) was synthesized from 3,3′‐diaminobenzidine and 2,2‐bis(4‐carboxyphenyl)hexafluoropropane. The polymer was soluble in N‐methylpyrrolidinone and dimethylacetamide and had an inherent viscosity of 2.5 dL/g measured in dimethylacetamide at a concentration of 0.5 g/dL. The 5% weight loss temperature of the polymer was 520 °C. Proton‐conducting PBI membranes were prepared via solution casting and doped with different amounts of phosphoric acid. In the methanol permeability measurement, the PBI membranes showed much better methanol barrier ability than a Nafion membrane. The proton conductivity of the acid‐doped PBI membranes increased with increasing temperatures and concentrations of phosphoric acid in the polymer. The PBI membranes showed higher proton conductivity than a Nafion 117 membrane at high temperatures. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4508–4513, 2006     

Robust Reliable Control for Uncertain Time-Delay Systems with IQC Performance

A robust reliable control with integral quadratic constraint (IQC) performance for a class of uncertain systems with state and input delays is considered in this paper. Two classes of failure situations for sensor or actuator are studied. In the first class, a delay-dependent criterion for time-delay systems without perturbations is proposed to design the reliable control with IQC performance. Next, a criterion for uncertain time-delay systems with parameter uncertainties is obtained via simple derivations. The linear matrix inequality (LMI) approach is used to design a robust reliable state feedback control with IQC performance. In the second class, a reliable control with IQC performance is also provided from he previous method. A numerical example is given to illustrate the effectiveness of the procedure. The research reported here was supported by the National Science Council of Taiwan, ROC under Grant NSC 95-2221-E-022-019.     

白血病人血液的光声光谱

利用光声光谱对不同类型的白血病患者和正常人的全血进行检测，发现白血病患者与正常人全血光谱图特征峰有明显差异，结果提示患者全血的光声光谱图可能对早期白血病诊断及白血病分型具有较大的临床意义。     

Synthesis and viscoelastic characterization of sulfonated chitosan solutions

In this study, sulfonated chitosan (SCS) with a water-soluble property was synthesized and rheologically characterized. The Maxwell Model can accurately describe a regular chitosan (CS) solution. The G′, G″ crossover shifted toward lower frequencies as the CS concentration increased, revealing an increase of relaxation time. A frequency–concentration superposition master curve of CS solution was therefore plotted and well fitted by the experiment result. However, a modified Maxwell Model, which captures the occurrence of the quasi-plateau region of G′ in the low-frequency range, representing the initially falsely connected structure between the sulfonic acid groups and the protonated ammonium groups, was proposed for the SCS solution. The crossover of G′ and G″ was found to be independent of the SCS concentration, indicating its lower molecular weight yields a high overlap concentration, Ce. The rheological properties of SCS solutions can be affected as the following factors are increased in the order of declining effect; pH level > temperature > salt concentration.     

A study on the extension of a VOF/PLIC based method to a curvilinear co-ordinate system

The conventional volume-of-fluid method has the potential to deal with large free surface deformation on a fixed Cartesian grid. However, when free-surface flows are within or over complex geometries of industrial relevance, such as free-surface flows over offshore oil platforms, it is advantageous to extend the method originally written in Cartesian forms into non-Cartesian forms. In the present study, an algorithm similar to the algorithm described by Rudman in 1997 is proposed for use with curvilinear co-ordinates. This extension results in the ability to model complex geometries which could not be modelled using the original algorithm. Excellent agreement between the solutions obtained on both orthogonal and non-orthogonal meshes is achieved, although in general the L ₁ error, based on the exact solution, on the non-orthogonal mesh is slightly higher than that on the orthogonal mesh. The extended fluid flow solving capacity of the present method is demonstrated through its application to a non-orthogonal Rayleigh–Taylor instability problem.