Cholesterol‐/Estradiol‐Appended Alkynylplatinum(II) Complexes as Supramolecular Gelators: Synthesis,Characterization, Photophysical and Gelation Studies

A series of cholesterol‐/estradiol‐appended alkynylplatinum(II) complexes with tridentate N‐donor ligands, based on 2,6‐bis(1‐alkylpyrazol‐3‐yl)pyridine, has been synthesized and characterized by ¹H NMR spectroscopy, FAB‐mass spectrometry, and elemental analysis. Their photophysical properties have also been investigated. Computational studies have been performed to provide insights into the nature of the electronic transitions. Some of the complexes have been found to form stable thermo‐ and mechanoresponsive supramolecular gels.     

Synthesis of P-chirogenic diarylphosphinoacetic acids and their proline derivatives for palladium-catalysed allylic alkylation reactions

The synthesis of P-chirogenic diarylphosphinocarboxylic acids was achieved, from which a new class of amido- and amino-diphosphine ligands (PNP*) were derived, containing an l-proline backbone. The catalytic activities of the novel ligands were evaluated in the palladium-catalysed allylic alkylation reaction of 1,3-diphenylpropenyl acetate.     

Lagrange multipliers theorem and saddle point optimality criteria in mathematical programming

We prove a version of Lagrange multipliers theorem for nonsmooth functionals defined on normed spaces. Applying these results, we extend some results about saddle point optimality criteria in mathematical programming.     

Tuned Transport Path of Perovskite MAPbI3-based Memristor Structure

In this study, the features of resistive random access memory (RRAM) employing a straightforward Cr/MAPbI₃/FTO three-layer structure have been examined and clarified. The device displays various resistance switching (RS) behavior at various sweep voltages between 0.5 and 5 V. The RS effect has a conversion in the direction of the SET and RESET processes during sweeping for a number of cycles at a specific voltage. The directional change of the RS processes corresponds to the dominant transition between the generation/recombination of iodide ion and vacancy in the MAPbI₃ perovskite layer and the electrochemical metallization of the Cr electrode under the influence of an electric field, which results in the conductive filament (CF) formation/rupture. At each stage, these processes are controlled by specific charge conduction mechanisms, including Ohmic conduction, space-charge-limited conduction (SCLC), and variable-range hopping (VRH). By identifying the biased voltage and the quantity of voltage sweep cycles, one can take a new approach to control or modulate the pathways for effective charge transport. This new approach is made possible by an understanding of the RS characteristics and the corresponding mechanisms causing the variation of RS behavior in the structure.     

Synthesis and characterization of a new disubstituted polyacetylene containing indolylazo moieties in side chains

A new disubstituted polyacetylene with indolylazo moieties in its side chains ( 9 ) was synthesized by a post functionalization strategy, which was difficult, or perhaps impossible, to obtain from the direct polymerization of its corresponding monomer. The polymer is soluble in common solvents and thermally stable. The polymer shows good optical transparency with an absorption maximum at 393 nm and a band edge at ～530 nm. Its poled film exhibits a resonant d₃₃ value of 17.9 pm/V and its optical nonlinearity is resistant to thermal decay at up to 147 °C. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5672–5681, 2006     

Operational competitiveness analysis on software development

The focus of this study is the application of a non-parametric model called operational competitiveness rating analysis (OCRA), to obtain ratings that gauge the relative operational performance of the application software development teams of a large bank in Hong Kong. The computed ratings would be the basis of important management decisions relating to the connection between personnel performance and benefits. This application of OCRA requires the values of resources consumed and outputs generated. Cost figures were used to measure the teams' resource consumption. The value of the teams' software output was measured by function point analysis. The performance ratings obtained by OCRA are compared with data envelopment analysis (DEA) ratings and ratio scores. Comments are offered on the implementation of the proposed approach.     

Statistical model of polar nematic polymers

The interaction in specially designed polymers may be dominated by the first rank P₁(cos β) type potential instead of the second rank P₂(cos β) type, as in conventional liquid crystal polymers (P₁(cos β) and P₂(cos β) are the first and second Legendre polynomials, respectively of the angle made by the polymer segments with respect to the preferred direction or director). The ordering of the polymers is envisaged in terms of the worm-like theory. The polymers show a polar nematic phase, that is a ferroelectric phase. These polymers have certain interesting properties, such as a second order polar nematic—isotropic transition, and related critical features. These materials are expected to exhibit giant dielectric responses. For more general polymer systems with interactions of both P₁(cos β) and P₂(cos β) types, we predict a peculiar phase behaviour.     

Estimation of the Scale Matrix and its Eigenvalues in the Wishart and the Multivariate F Distributions

In this paper, the problem of estimating the scale matrix and their eigenvalues in a Wishart distribution and in a multivariate F distribution (which arise naturally from a two-sample setting) are considered. A new class of estimators which shrink the eigenvalues towards their arithmetic mean are proposed. It is shown that the new estimator which dominates the usual unbiased estimator under the squared error loss function. A simulation study was carried out to study the performance of these estimators.