1.3-μm GaInAsP/InP buried-ridge-structure laser and itsmonolithic integration with photodetector using reactive ion beametching

A 1.3 μm GaInAs/InP BRS laser is monolithically integrated with a photodiode. reactive ion beam etching technique (RIBE) is used for the realization of the laser mesa stripe and for the separation of the laser and the photodetector sections. Influence of the laser-detector gap width, the detector facet inclination, and the laser beam waist on the coupling efficiency between LD and PD are discussed theoretically and experimentally. Coupling efficiency as high as 50 μA/mW is obtained by optimizing the structure. A packaged pigtailed integrated LD-PD is realized, in which the signal emitted from the rear laser facet is detected by the integrated photodiode and used to stabilize the laser output power, through a hybrid feedback circuit, to within 0.1% over 55°C temperature range     

Rheological and viscoelastic behavior of dynamically vulcanized poly(vinyl chloride)–epoxidized natural‐rubber thermoplastic elastomers

Dynamically vulcanized poly(vinyl chloride)–epoxidized natural‐rubber thermoplastic elastomers (PVC–ENR TPEs) were prepared using a semi‐EV vulcanization system. The compounds were melt‐mixed, and the rheological behavior was evaluated. The effect of curatives concentration on the rheological behavior using the shear dependence of viscosity and the activation energy for viscous flow was evaluated. Viscoelastic behavior was also investigated with the Monsanto MDR 2000. The parameters studied include the elastic modulus at maximum torque, the loss peak at maximum torque, and their ratio (tan δ). The data obtained were correlated with the material properties, such as hardness and resilience. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2886–2893, 1999     

Rheological properties of poly(vinyl chloride)/epoxidized natural rubber blends. Part I: Composition dependence and the effect of compounding conditions

Epoxidized natural rubber is a recently commercialized modified form of natural rubber. This paper is part of our continuing effort to study the responses of this new material to melt mixing and other shaping processes. The Shimadzu capillary rheometer was used to evaluate the composition dependence of miscibility of polyvinyl chloride/epoxidized natural rubber blends (PVC/ENR blends). The rheometer was also used to evaluate the effect of compounding parameters on the rheological properties of the blends. The results confirmed PVC/ENR blends as miscible systems that show a synergism in apparent shear viscosity highlighted by the positive deviation from the logarithmic additivity rule. These results based on capillary rheometry are also in very good agreement with our earlier attempt to predict optimum mixing from torque rheometry by using the Brabender Plastogram as an indicator.     

High‐density polyethylene/ultrahigh‐molecular‐weight polyethylene blend. I. The processing,thermal, and mechanical properties

Various blend ratios of high‐density polyethylene (HDPE) and ultrahigh‐molecular‐weight polyethylene (UHMWPE) were prepared with the objective of determining their suitability as biomaterials. Although the presence of HDPE in the blends enabled melt processing, the presence of UHMWPE helped to improve the toughness of the resulting blends. The processability of the blends was investigated with the Brabender torque, which was used as an indication of the optimum blend conditions. The blends were characterized with differential scanning calorimetry. The mechanical tests performed on the blends included tensile, flexural, and impact tests. A 50:50 (w/w) blend yielded optimum properties in terms of the processability and mechanical properties. The tensile property of the 50:50 blend was intermediate between those of HDPE and UHMWPE, but the strain at break increased 200% in comparison with that of both neat resins. The energy at break of the 50:50 blend revealed an improvement in the toughness. The fracture mechanism was also investigated with scanning electron microscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 413–425, 2005