An object is to provide polycrystalline diamond applicable to diverse applications; and a water jet orifice, a stylus for gravure printing, a scriber, a diamond cutting tool, and a scribing wheel that include such polycrystalline diamond. This object is achieved by polycrystalline diamond obtained by converting and sintering non-diamond carbon under an ultrahigh pressure and at a high temperature without addition of a sintering aid or a catalyst, wherein sintered diamond grains constituting the polycrystalline diamond have an average grain diameter of more than 50 nm and less than 2500 nm and a purity of 99% or more, and the diamond has a D90 grain diameter of (average grain diameter+average grain diameter0.9) or less.

An apparatus for treating a wafer-shaped article includes a rotary chuck configured to hold a wafer-shaped article of a predetermined diameter such that a surface of the wafer-shaped article facing the rotary chuck is spaced from an upper surface of the rotary chuck. A ring is mounted on the rotary chuck, and includes a first upper surface overlapping an outer peripheral edge of a wafer-shaped article when positioned on the rotary chuck and a second upper surface positioned radially inwardly of the first surface. The second upper surface is elevated relative to the first upper surface, to define an annular gap between the second upper surface and a wafer-shaped article when positioned on the spin chuck that is smaller than a distance between the first upper surface and a wafer-shaped article when positioned on the rotary chuck.

In a silicon carbide single crystal wafer, a dislocation density contained therein is 3500 dislocations/cm.sup.2 or less, and a difference of the dislocation density among a wafer central part, a wafer peripheral part and a wafer intermediate part is less than 50% of an average value thereof.

A CaF.sub.2 polycrystalline body which is a polycrystalline body constituted of CaF.sub.2 and of which an average grain size of crystalline grains is 200 m or more, and a method for producing a CaF.sub.2 polycrystalline body, the method including a process of introducing a compact which is obtained by using a CaF.sub.2 powder raw material into a vacuum sintering furnace and sintering at a temperature of not higher than 1400 C. for six hours or more, thereby obtaining the CaF.sub.2 polycrystalline body.

Provided are nanostructures and optical devices having the nanostructures. The nanostructure may include a carbon nanomaterial layer, a nanopattern formed on the carbon nanomaterial layer, and a metal layer formed on a surface of the nanopattern. The nanostructure may be formed in a ring shape, and the metal layer may include a plurality of metal layers formed of different metals.

One embodiment of the invention includes a frictional damping insert including a body constructed and arranged to be incorporated into a product and to provide frictional damping of the product, the body including lines of weakness constructed and arranged to segment the body into separate sections upon exposure to a molten material.

In some embodiments, a target assembly, for use in a substrate processing chamber having a process shield, may include a backing plate having a first side and an opposing second side, wherein the second side comprises a first surface having a first diameter bounded by a first edge; a target material having a first side bonded to the first surface of the backing plate; wherein the first edge is an interface between the backing plate and the target material; a plurality of slots disposed along an outer periphery of the backing plate extending from the first side of the backing plate toward the second side of the backing plate, wherein the plurality of slots are configured to align the target assembly with respect to the process shield.

An adhesive film for a polishing pad including a plurality of through holes extended from a top surface to a bottom surface of the adhesive film, wherein a volume fraction of the plurality of through holes is 3% to 20% based on a total volume of the adhesive film, is disclosed.