Methods are known for producing an anti-resonant hollow-core fiber which has a hollow core extending along a fiber longitudinal axis and an inner jacket region that surrounds the hollow core, said jacket region comprising multiple anti-resonant elements. The known methods have the steps of: providing a cladding tube that has a cladding tube inner bore and a cladding tube longitudinal axis along which a cladding tube wall extends that is delimited by an interior and an exterior; forming a number of precursors for anti-resonant elements at target positions of the cladding tube wall; and elongating the primary preform in order to form the hollow-core fiber or further processing the primary preform in order to form a secondary preform from which the hollow-core fiber is drawn. The aim of the invention is to achieve a high degree of precision and an exact positioning of the anti-resonant elements in a sufficiently stable and reproducible manner on the basis of the aforementioned methods. This is achieved in that the formation of the anti-resonant element precursors includes the formation of elongated pressure chambers, each of which adjoins a wall that can be deformed under pressure and heat in the region of the target positions of the anti-resonant elements and which cause a section of the deformable wall to protrude in the direction of the cladding tube inner bore under the effect of pressure and heat, thereby forming an anti-resonant element or a precursor for same, while carrying out a process according to step (c).

A shaped tube (50,51) for use as a component in the fabrication of an antiresonant hollow core optical fibre, the shaped tube having a side wall with a transverse cross-sectional shape comprising a number of major curved portions (52) alternating with the same number of minor substantially straight portions (54), each curved portion (52) having an inwardly curving shape, and each straight portion (54) being equidistant from a central longitudinal axis of the shaped tube (50,51).

A method of forming one of a plurality of encapsulated crystalline particles includes feeding a coaxial feed wire downwardly such that a first wire end of the coaxial feed wire is positioned at a heating source. The coaxial feed wire includes a crystalline wire core, and an amorphous shell surrounding the crystalline wire core. The first end of the coaxial feed wire is heated at the heating source, thereby forming a molten pendant drop at the first wire end. The plurality of encapsulated crystalline particles are emitted from the molten pendant drop onto a collector located below the molten pendant drop.

A method of forming one of a plurality of encapsulated crystalline particles includes feeding a coaxial feed wire downwardly such that a first wire end of the coaxial feed wire is positioned at a heating source. The coaxial feed wire includes a crystalline wire core, and an amorphous shell surrounding the crystalline wire core. The first end of the coaxial feed wire is heated at the heating source, thereby forming a molten pendant drop at the first wire end. The plurality of encapsulated crystalline particles are emitted from the molten pendant drop onto a collector located below the molten pendant drop.

A method for thermally treating an annular region of an inner surface of a glass container produced from a borosilicate glass tube is provided. The annular region is disposed at a tubular portion of the glass container and is disposed adjacent to a glass container bottom. The method includes: forming the glass container bottom from the glass tube; heating the annular region of the inner surface of the tubular portion to a treatment temperature T.sub.Beh above the transformation temperature T.sub.G, wherein the annular region is adjacent to the glass container bottom; maintaining the treatment temperature T.sub.Beh for a certain time period; and cooling the glass container to room temperature.

A fabricating method for a quartz vial having a body for containing a substance, a bottom closing a lower end of the body, a cylindrical neck disposed above the body, and a cylindrical mouth disposed above the neck and having an outer diameter larger than that of the neck includes the steps of forming an outer peripheral surface of the neck by shaving, and joining by thermal fusion, to the neck, the body that is separately fabricated. Thus, quartz vials having a predetermined shape can be mass-fabricated.

An apparatus for the automated production of glass assemblies comprises: a turning machine with at least two spindles which are rotatable about a common axis of rotation and which each have a workpiece holder, wherein the workpiece holders are arranged opposite one another; one or more gas burners or lasers fixed on a first tool carriage which is movable in parallel and/or perpendicularly to the axis of rotation; one or more drives for driving a rotational movement of the spindles and a movement of the first tool carriage; a pressure module including a pump device at least one working cylinder for applying a pressure to an inner tube and/or to a space between the inner tube and an outer tube; and a control unit configured to control the burners or lasers, one or more drives, the first tool carriage and the pressure module.

An apparatus for the automated production of glass assemblies comprises: a turning machine with at least two spindles which are rotatable about a common axis of rotation and which each have a workpiece holder, wherein the workpiece holders are arranged opposite one another; one or more gas burners or lasers fixed on a first tool carriage which is movable in parallel and/or perpendicularly to the axis of rotation; one or more drives for driving a rotational movement of the spindles and a movement of the first tool carriage; a pressure module including a pump device at least one working cylinder for applying a pressure to an inner tube and/or to a space between the inner tube and an outer tube; and a control unit configured to control the burners or lasers, one or more drives, the first tool carriage and the pressure module.

A method of forming one of a plurality of encapsulated crystalline particles includes feeding a coaxial feed wire downwardly such that a first wire end of the coaxial feed wire is positioned at a heating source. The coaxial feed wire includes a crystalline wire core, and an amorphous shell surrounding the crystalline wire core. The first end of the coaxial feed wire is heated at the heating source, thereby forming a molten pendant drop at the first wire end. The plurality of encapsulated crystalline particles are emitted from the molten pendant drop onto a collector located below the molten pendant drop.

A method of forming one of a plurality of encapsulated crystalline particles includes feeding a coaxial feed wire downwardly such that a first wire end of the coaxial feed wire is positioned at a heating source. The coaxial feed wire includes a crystalline wire core, and an amorphous shell surrounding the crystalline wire core. The first end of the coaxial feed wire is heated at the heating source, thereby forming a molten pendant drop at the first wire end. The plurality of encapsulated crystalline particles are emitted from the molten pendant drop onto a collector located below the molten pendant drop.