An optimized fiber tow orientation, to achieve substantially uniform fiber tow volume across the web, e.g., from inner diameter (ID) to the outer diameter (OD) of a disc shaped preform, without substantially varying the angles of the plurality of fiber tows radially or circumferentially is described herein. Utilizing the systems and processes described herein, a net shape preform may be created. A substantially continuous fiber tow may be used to form the preform. The fiber tow angle of each fiber tow may vary, from more radial, such as at the ID, to more tangential, such as at the OD, as the radius increases, such that there is substantially uniform thickness and substantially uniform areal weight from ID to OD of the preform or layer.

A method of producing a spiral cut transparent tube using laser machining includes using an ultrafast laser beam comprising a burst of laser pulses and focusing the laser beam on the transparent tube to enable relative movement between the laser beam and the transparent tube by moving the laser beam, the glass tube or both the laser beam and the glass tube. A beam waist is formed external to the surface of the transparent tube wherein the laser pulses and sufficient energy density is maintained within the transparent tube to form a continuous laser filament therethrough without causing optical breakdown. The method and delivery system makes a spiral cut in the transparent tube.

Bulk single crystals of AlN having a diameter greater than about 25 mm and dislocation densities of about 10,000 cm.sup.2 or less and high-quality AlN substrates having surfaces of any desired crystallographic orientation fabricated from these bulk crystals.

The objective of the present invention is to provide a porous ultra-thin polymer film, and a method for producing said porous ultra-thin polymer film. The present invention provides a porous ultra-thin polymer film with a film thickness of 10 nm-1000 nm. In addition, the present invention provides a method for producing a porous ultra-thin polymer film, comprising the steps of: dissolving two types of mutually-immiscible polymers in a first solvent in an arbitrary proportion to obtain a solution; applying the solution onto a substrate and then removing the first solvent from the solution applied onto the substrate to obtain a phase-separated ultra-thin polymer film that has been phase-separated into a sea-island structure; and immersing the ultra-thin polymer film in a second solvent which is a good solvent for the polymer of the island parts but a poor solvent for a polymer other than the island parts to remove the island parts, thereby obtaining a porous ultra-thin polymer film.

A composite substrate production method of the invention includes (a) a step of mirror polishing a substrate stack having a diameter of 4 inch or more, the substrate stack including a piezoelectric substrate and a support substrate bonded to each other, the mirror polishing being performed on the piezoelectric substrate side until the thickness of the piezoelectric substrate reaches 3 m or less; (b) a step of creating data of the distribution of the thickness of the mirror-polished piezoelectric substrate; and (c) a step of performing machining with an ion beam machine based on the data of the thickness distribution so as to produce a composite substrate have some special technical features.

A reinforcing ring (10) for a fenestration (32) of a stent graft which can be surface treated such as by passivation and/or electropolishing. The reinforcing ring has several turns of a substantially inextensible resilient wire (12) in a circular two dimensional planar shape and terminal ends (14) at each end of the wire. The terminal ends each comprising a loop (14) and a tail (16). The tail is folded back and extends around the circular shape. Each of the tails of the terminal loops can have an enlarged end. The reinforcing ring can be straightened out for surface treatment such as passivation and/or electropolishing with substantially no part of the circular shape, the loops or tails touching each other.

A composite substrate production method of the invention includes (a) a step of mirror polishing a substrate stack having a diameter of 4 inch or more, the substrate stack including a piezoelectric substrate and a support substrate bonded to each other, the mirror polishing being performed on the piezoelectric substrate side until the thickness of the piezoelectric substrate reaches 3 m or less; (b) a step of creating data of the distribution of the thickness of the mirror-polished piezoelectric substrate; and (c) a step of performing machining with an ion beam machine based on the data of the thickness distribution so as to produce a composite substrate have some special technical features.

The invention discloses a blank for producing dental shaped parts which consists entirely of porous glass without crystalline portions. The density of the blank is between 50% and 95% of its theoretical density. It has a discoidal shape with a diameter of at least 20 mm. The blank is produced by a process in which glass powder is first pressed at a pressure of between 10 MPa and 300 MPa and this green body is (pre-)sintered at a temperature of between 580 C. and 750 C. to form a blank of porous glass without crystalline portions. From the obtained blank, monolithic dental shaped parts can be obtained by mechanical processing followed by sintering, wherein a process according to the invention for stabilizing the shape of the shaped parts is used.

A coin comprises a core made of a first metal, an outer ring surrounding the core concentrically and made of a further metal, and a central ring between the core and outer ring fixedly connected thereto. The central ring consists of an electrically insulating material. Further, the central ring is transparent to electromagnetic waves of a first wavelength range and is less transparent or not transparent to a second wavelength range. Methods for testing the coin are also described.

A silicon member for a semiconductor apparatus is provided. The silicon member has an equivalent performance to one fabricated from a single-crystalline silicon even though it is fabricated from a unidirectionally solidified silicon. In addition, it can be applied for producing a relatively large-sized part. The silicon member is fabricated by sawing a columnar crystal silicon ingot obtained by growing a single-crystal from each of seed crystals by placing the seed crystals that are made of a single-crystalline silicon plate on a bottom part of a crucible and unidirectionally solidifying a molten silicon in the crucible.