Green's functions associated with the edth operators

An integral representation for the inverses of the differential operators called edth is given in the two cases of particular interest. This operator plays a large role in the study ofH spaces and of self-dual solutions to the Yang-Mills field equations in the asymptotic domain.     

Molar extinction coefficients of some carbohydrates in aqueous solutions

Molar extinction coefficients of some carbohydrates viz. l-arabinose (C₅H₁₀O₅), d-glucose (C₆H₁₂O₆), d-mannose (C₆H₁₂O₆), d-galactose (C₆H₁₂O₆), d(-) fructose (C₆H₁₂O₆) and maltose (C₁₂H₂₄O₁₂) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by gamma ray transmission method in a narrow beam good geometry set-up. These coefficients have been found to depend upon the photon energy following a 4-parameter polynomial. These extinction coefficients for different sugars having the same molecular formula have same values varying within experimental uncertainty. Within concentration ranges studied, Beer-Lambert law is obeyed very well.     

Melting behavior of poly(ether ether ketone) in its blends with poly(ether imide)

We detail the melting behavior of poly(ether ether ketone) (PEEK) and investigate its melting behavior in miscible blends with poly(ether imide) (PEI). The determination of the equilibrium melting point (T_m⁰) of PEEK is discussed by considering its inhomogeneous morphology. T_m⁰ is obtained by a long extrapolation of a Hoffman–Weeks plot to 384°C. Hindrance of PEEK crystal reorganization induced by PEI during heating is observed over the blend composition investigated (20–75 wt % PEEK). This behavior is correlated with the incorporation of PEI in the interlamellar zones of PEEK crystals. The interaction parameter χ of PEEK/PEI blends is estimated by the equilibrium melting point depression. This gives the interaction density B = ?1.2 cal/cm³, and x = ?0.40 at 400°C. © 1993 John Wiley & Sons, Inc.     

A convenient route for the synthesis of s,s-and R,R-warfarin alcohols

S,S-and R,R-warfarin alcohols 3 are prepared in good yield and in 99% d.e. (diastereomeric excess) by the reaction of S- or R-warfarin 1 with S or R-Alpine-Hidride 2.     

Blends of poly(butylene terephthalate) and a polyarylate before and after transesterification

Blends of poly(butylene terephthalate) (PBT) and a copolyester of bisphenol-A with 50% terephthalate-50% isophthalate (PAr), before and after transesterification, have been studied by thermal and dynamic mechanical tests to determine crystallinity and phase behavior. Blends without transesterification, as prepared by solution precipitation, show a single T_g, indicating amorphous miscibility of PBT and PAr. A melting-point depression for PBT crystals is not observed; this means that PBT crystallizes excluding PAr and the entropy of melting is small. The highest fractional crystallinity for PBT is obtained at 20-35% of PAr. Transesterified blends were obtained by holding the physical blends at 250°C for up to 16 h. The transesterified systems show higher T_g's than the corresponding physical blends and also show a marked melting-point depression and lesser PBT crystallinity at the corresponding increased PAr content.