Structural stabilization of phase separating PC/polyester blends through interfacial modification by transesterification reaction

Competition between phase separation and transesterification in immiscible polymer blends of polycarbonate (PC) and a copolyester (PET) is studied as a function of time and temperature by differential scanning calorimetry (DSC) and small-angle neutron scattering (SANS). We found that (1) Global structure coarsens at T ≤ 200°C due to the dominance of phase separation over transesterification and melts at T ≤ 220°C due to the dominance of transesterification at the domain interface. However, transesterification is slow but still significant even at T ≤ 200°C. (2) An intricate balance of transesterification and phase separation rates controls global and interfacial structures. (3) Interfacial structures become measurable under certain conditions, and the interfacial thickness between PC or PET and the copolymers generated by transesterification increases with time. (4) DSC results are consistent with results obtained by SANS, but the latter is more sensitive than the former and differentiates the structural change at different length scales caused by phase separation and transesterification. © 1994 John Wiley & Sons, Inc.     

Perpendicular anisotropy of Co3Pt deposited on the NiFeMo/Ru buffer

The multilayer of Ta/NiFeMo/Ru/Co₃Pt was sputter deposited on the Si (1 0 0) wafer. Using the NiFeMo buffer layer greatly enhanced the texture of Co₃Pt layer. The enhanced texture increased the perpendicular magnetic anisotropy of Co₃Pt. According to the VSM and XRD results, only the 5 nm of NiFeMo was good enough to produce the texture and perpendicular anisotropy in Co₃Pt layer. The perpendicular anisotropy was attributed to the existence of short-range-ordered HCP structure of Co₃Pt.     

Model-based clustering for integrated circuit yield enhancement

This paper studies the defect data analysis method for semiconductor yield enhancement. Given the defect locations on a wafer, the local defects generated from the assignable causes are classified from the global defects generated from the random causes by model-based clustering, and the clustering methods can identify the characteristics of local defect clusters. The information obtained from this method can facilitate process control, particularly, root-cause analysis. The global defects are modeled by the spatial non-homogeneous Poisson process, and the local defects are modeled by the bivariate normal distribution or by the principal curve.     

Calculation of reactor impedance for helicon discharge

We solve the Maxwell-Boltzmann equations and calculate reactor impedance for helicon device with the Nagoya type III antenna using a finite, width modeling of antenna current and inspect the dependence of various components of impedance on discharge parameters. The total resistance is divided into various components such as electron-ion contributions and axial-perpendicular field contributions. Moreover, the total resistance can be approximately expressed as the sum of TG and helicon contributions in a wide range of parameters     

Development of a microfluidic device for simultaneous mixing and pumping

We conducted experimental and numerical studies aimed at developing a microfluidic device capable of simultaneous mixing while pumping. The proposed multifunctional device makes use of alternating current electroosmotic flow and adopts an array of planar asymmetric microelectrodes with a diagonal or herringbone shape. The pumping performance was assessed in terms of the fluid velocity at the center of the microchannel, obtained by micro PIV. To assess the mixing, flow visualizations were carried out over the electrodes to verify the lateral flows. The mixing degree was quantified in terms of a mixing efficiency obtained by three-dimensional numerical simulations. The results showed that simultaneous mixing and pumping was achieved in the channels with diagonal or herringbone electrode configurations. A herringbone electrode configuration showed better pumping compared with a reference, as well as enhanced mixing.     

Ionic liquid mediated efficient reduction of nitroarenes using stannous chloride under sonication

Nitroarenes were rapidly reduced to the corresponding aromatic amines using stannous chloride in ionic liquid as a safe and recyclable reaction medium under sonication. The method is environmentally benign and sensitive functional groups remain unaffected.     

Crystal structure of 6-oxa-3,9-dithiabicyclo[9.2.2]pentadeca-1(15),11,13-triene.

The structure of an S2O mixed-donor macrocycle incorporating para-substituted xylyl subunit was characterized by a single crystal X-ray analysis. The crystal structure shows an exo-dentate orientation of sulfur and oxygen donor atoms due to the fully stretched aliphatic ring conformation. Thus all of torsional angles between donor atoms are arranged anti and S...S distance in a ring is 6.764(1)A, which is larger than those values of ortho- and meta-type analogs. The observed high rigidity of the ring conformation may induce the extraordinary behaviors in chelation.     

A Decomposition Method for Solving Nonlinear Systems of Compartment Models

In this paper we consider a two-compartment model and analyze the underlying nonlinear system of differential equations that arises from studying such models. In particular, we apply a decomposition method to solve the system numerically and then compare the results with other well-known methods such as the fourth-order Runge-Kutta method.