Abstract: A fiber consisting essentially of polyethylene terephthalate capable of being dyed under normal pressure and having an initial modulus at 30.degree. C. of about 55 g/d to about 130 g/d, a relationship between a peak temperature [T.sub.max (.degree.C.)] at the peak of a dynamic mechanical loss tangent (tan .delta.) measured with a frequency of 110 Hz and a peak value of the dynamic mechanical loss tangent [(tan .delta.).sub.max ] represented by the formula:(tan .delta.).sub.max .gtoreq.1.times.10.sup.-2 (T.sub.max -105)and a (tan .delta.).sub.max of about 0.14 to about 0.30 and a dynamic mechanical loss tangent at 220.degree. C. (tan .delta..sub.220) of at most about 0.055. The fiber is produced by subjecting a polyethylene terephthalate fiber obtained at a spinning speed of at least about 4000 m/min. to heat treatment at a temperature ranging from a temperature at which a dynamic modulus (E') of the fiber deviates from a tangent line at 180.degree. C.

Abstract: A fiber consisting essentially of polyethylene terephthalate capable of being dyed under normal pressure and having an initial modulus at 30.degree. C. of about 55 g/d to about 130 g/d, a relationship between a peak temperature ]T.sub.max (.degree.C.)] at the peak of a dynamic mechanical loss tangent (tan .delta.) measured with a frequency of 110 Hz and a peak value of the dynamic mechanical loss tangent [(tan .delta.).sub.max ] represented by the formula:(tan .delta.).sub.max .ltoreq.1.times.10.sup.-2 (T.sub.max -105)and a (tan .delta.).sub.max of about 0.14 to about 0.30 and a dynamic mechanical loss tangent at 220.degree. C. (tan .delta..sub.220) of at most about 0.055. The fiber is produced by subjecting a polyethylene terephthalate fiber obtained at a spinning speed of at least about 4000 m/min. to heat treatment at a temperature ranging from a temperature at which a dynamic modulus (E') of the fiber deviates from a tangent line at 180.degree. C.

Abstract: Vegetable beverages are clarified or stabilized by using an adsorbent material consisting essentially of a specified N-substituted polyamide or polyamide mixture. The specified polyamide is such that 0.5% to 65% in number of the hydrogen atoms linked to the nitrogen atoms of the amide linkages in the main chain are substituted with substituents represented by the formula-(CH.sub.2).sub.n -Rwhere n is an integer of 1 to 4 and R is at least one member selected from a hydrogen atom, a hydroxyl group and an alkoxy group having 1 to 4 carbon atoms and Rs in the molecule are the same as or different from each other.