Yuji Yamaguchi

Measurement and correlation of liquid-liquid equilibria and partition coefficients of hydrolytic enzymes for DEX T500 + PEG20000 + water aqueous two-phase system at 20 °C

Abstract The liquid-liquid equilibria (LLE) for the dextran T500 (DEX T500) + poly(ethylene glycol) 20000 (PEG20000) + water aqueous two-phase system were measured at 20 °C. Furthermore, the molecular weight distributions of DEX and PEG in the top and bottom phases were measured. The partition coefficients (Kp) of hydrolytic enzymes, α-amylase, β-amylase and glucoamylase were also measured. LLE and Kp were correlated using a modified Flory-Huggins equation developed for aqueous systems. The molecular weight distribution of DEX was expressed by a Γ distribution function. LLE and molecular weight distributions were correlated successfully using a continuous thermodynamic approach. The partition coefficients were also correlated with good agreement.

An intranuclear cascade model for inelastic scattering and breakup reactions involving deuterons and alpha particles

ABSTRACT The intranuclear cascade model is extended to cluster-induced (deuteron and alpha particle) nuclear reactions involving inelastic scattering and breakup reactions. The proposed model explains the projectile breakup process by describing the projectile cluster as a superposition of several states. The incident cluster and the produced cluster are assumed to be collections of independent particles and may undergo nuclear interaction through nucleon–nucleon interaction with the target nucleus. Trajectory deflections for the projectile and ejecta are incorporated in the model to account for angular distributions. Calculations with the proposed model followed by the generalized evaporation model are performed for validation by comparing with experimental double-differential cross-section spectra produced by bombarding an 27Al target separately with 80-MeV and 99.6-MeV deuterons and 140-MeV alpha particles. The calculation results show good agreement with experimental spectra.

Classical vector analysis to study angular momentum of evaporated protons

The classical vector analysis is proposed to deduce angular momenta of evaporated protons from medium-energy proton-nucleus reactions. The intranuclear cascade model is applied to extract the angular momentum vector of highly excited nucleus, which is in equilibrium after the cascade process. The mixing ratios of angular momenta are determined to fit experimental angular distributions. Resultant ratios show clear tendency in terms of target mass.