A hollow fibre membrane having a coiled, a hemihelix, a helical or an undulated native form, in which the membrane can be stretched by up to 4-times its original length with no plastic deformation, and wherein the native form of the membrane is produced by the asymmetric flow of liquid polymer through an opening of a die or nozzle.

A composite structure is disclosed forming part of a wall of a liquid hydrogen tank, and including at least one thermal protection device having one or more of hollow fibers, such as to create thermal protection, for example a thermal barrier or a heat exchanger, which makes it possible to protect the composite structure in case of a high temperature gradient between the two faces thereof, while benefiting from the advantages of a composite material in terms of mass.

A lightweight heat-preserving fiber and a preparation method thereof are provided, wherein the fiber is prepared by measuring, composite spinneret's extruding, cooling, oiling, drawing, heat setting and winding a polyester melt. The composite spinneret has a hollow spinning hole and a circular spinning hole. The ratio of the micropore length of hollow spinning hole to circular spinning hole equals to the ratio of the equivalent diameter of hollow spinning hole to circular spinning hole multiplies the coefficient K, and the equivalent diameter is the ratio of the cross-sectional area to the circumference of the cross-section, the coefficient K ranges from 0.97 to 1.03. The oil agent contains a crown ether, and the content of the crown ether ranges from 67.30 to 85.58 wt %. The thermal conductivity of a knitted fabric having a basis weight of 100 g/m.sup.2 prepared by lightweight heat-preserving fiber is no larger than 0.150 W/m.Math.K.

A lightweight heat-preserving fiber and a preparation method thereof are provided, wherein the fiber is prepared by measuring, composite spinneret's extruding, cooling, oiling, drawing, heat setting and winding a polyester melt. The composite spinneret has a hollow spinning hole and a circular spinning hole. The ratio of the micropore length of hollow spinning hole to circular spinning hole equals to the ratio of the equivalent diameter of hollow spinning hole to circular spinning hole multiplies the coefficient K, and the equivalent diameter is the ratio of the cross-sectional area to the circumference of the cross-section, the coefficient K ranges from 0.97 to 1.03. The oil agent contains a crown ether, and the content of the crown ether ranges from 67.30 to 85.58 wt %. The thermal conductivity of a knitted fabric having a basis weight of 100 g/m.sup.2 prepared by lightweight heat-preserving fiber is no larger than 0.150 W/m.Math.K.

The present disclosure relates to a device and a process for cutting hollow fiber membranes having a large inner diameter.

The present disclosure relates to a device and a process for cutting hollow fiber membranes having a large inner diameter.

The invention relates to a cellulose-containing fibrous material for a nonwoven product, in particular in the form of a wiping cloth, cleaning cloth, sanitary product, medicinal product, or domestic cloth, wherein the fibrous material is designed as a tubular composite structure at least in part or in some regions, said structure having tubular cellulose acetate filaments. The invention additionally relates to a nonwoven product which has the fibrous material according to the invention and to a method for producing such a cellulose acetate-containing fibrous material.

The invention relates to a cellulose-containing fibrous material for a nonwoven product, in particular in the form of a wiping cloth, cleaning cloth, sanitary product, medicinal product, or domestic cloth, wherein the fibrous material is designed as a tubular composite structure at least in part or in some regions, said structure having tubular cellulose acetate filaments. The invention additionally relates to a nonwoven product which has the fibrous material according to the invention and to a method for producing such a cellulose acetate-containing fibrous material.

The present invention provides a porous carbon fiber which has an excellent permeation amount and excellent pressure resistance, which is prevented from the occurrence of detachment or cracking at an interface, and which can exhibit excellent properties needed for use as a support for a fluid separation membrane. The present invention is a porous carbon fiber having a bicontinuous porous structure, wherein the average value R.sub.ave of the R value of the outer surface and the R value of the inside is 1.0 or more and 1.8 or less, the absolute value ΔR of the difference between the R value of the outer surface and the R value of the inside is 0.05 or less, and R value is a carbonization progression degree calculated from a Raman spectrum in accordance with the following formula:
R value=(intensity of scattering spectrum at 1360 cm.sup.−1)/(intensity of scattering spectrum at 1600 cm.sup.−1).

Various implementations include a filament that includes three lobes that extend from a central portion of the filament, and the central portion defines an axial void. Each lobe bulges outwardly at its proximal end adjacent the central portion and has edges that form a continuous concave curve toward its distal end relative to an axis A-A that extends through the distal end of the respective lobe and the central portion of the filament. Thus, a width of each lobe at the proximal end thereof is greater than a width of each lobe at or adjacent the distal end, and adjacent edges of adjacent lobes intersect each other at concave proximal ends of the adjacent edges.