A method of fabrication of laser gain material and utilization of such media includes the steps of introducing a transitional metal, preferably Cr.sup.2+ thin film of controllable thickness on the ZnS crystal facets after crystal growth by means of pulse laser deposition or plasma sputtering, thermal annealing of the crystals for effective thermal diffusion of the dopant into the crystal volume with a temperature and exposition time providing the highest concentration of the dopant in the volume without degrading laser performance due to scattering and concentration quenching, and formation of a microchip laser either by means of direct deposition of mirrors on flat and parallel polished facets of a thin Cr:ZnS wafer or by relying on the internal reflectance of such facets.

A IIIA-VA group semi-conductor single crystal substrate (2) has one of or both of the following two properties: an oxygen content of 1.610.sup.16-5.610.sup.17 atoms/cm.sup.3 in a range from the surface to a depth of 10 m of the wafer, and an electron mobility of 4,800 cm.sup.2/V.Math.s-5,850 cm.sup.2/V.Math.s. Further, a method for preparing the semi-conductor single crystal substrate (2) comprises: placing a single crystal substrate (2) to be processed in a container (4); sealing said container (4), and keeping said single crystal substrate (2) to be processed at a temperature in the range of from the crystalline melting point 240 C. to the crystalline melting point 30 C. for 5 hours to 20 hours; preferably, keeping a gallium arsenide single crystal at a temperature of 1,000 C. to 1,200 C. for 5 hours to 20 hours.

A IIIA-VA group semi-conductor single crystal substrate (2) has one of or both of the following two properties: an oxygen content of 1.610.sup.16-5.610.sup.17 atoms/cm.sup.3 in a range from the surface to a depth of 10 m of the wafer, and an electron mobility of 4,800 cm.sup.2/V.Math.s-5,850 cm.sup.2/V.Math.s. Further, a method for preparing the semi-conductor single crystal substrate (2) comprises: placing a single crystal substrate (2) to be processed in a container (4); sealing said container (4), and keeping said single crystal substrate (2) to be processed at a temperature in the range of from the crystalline melting point 240 C. to the crystalline melting point 30 C. for 5 hours to 20 hours; preferably, keeping a gallium arsenide single crystal at a temperature of 1,000 C. to 1,200 C. for 5 hours to 20 hours.

We describe herein biocompatible single crystal Cu-based shape memory alloys (SMAs). In particular, we show biocompatibility based on MEM elution cell cytotoxicity, ISO intramuscular implant, and hemo-compatibility tests producing negative cytotoxic results. This biocompatibility may be attributed to the formation of a durable oxide surface layer analogous to the titanium oxide layer that inhibits body fluid reaction to titanium nickel alloys, and/or the non-existence of crystal domain boundaries may inhibit corrosive chemical attack. Methods for controlling the formation of the protective aluminum oxide layer are also described, as are devices including such biocompatible single crystal copper-based SMAs.

We describe herein biocompatible single crystal Cu-based shape memory alloys (SMAs). In particular, we show biocompatibility based on MEM elution cell cytotoxicity, ISO intramuscular implant, and hemo-compatibility tests producing negative cytotoxic results. This biocompatibility may be attributed to the formation of a durable oxide surface layer analogous to the titanium oxide layer that inhibits body fluid reaction to titanium nickel alloys, and/or the non-existence of crystal domain boundaries may inhibit corrosive chemical attack. Methods for controlling the formation of the protective aluminum oxide layer are also described, as are devices including such biocompatible single crystal copper-based SMAs.

A particle manufacturing method is disclosed. A particle manufacturing method according to one aspect of the present disclosure as a method of forming a spherical particle may include forming a structure for forming a structure of a protruding shape with a material composing of the particle on a first substrate, disposing substrates for disposing the first substrate such that the structure faces downward and disposing a second substrate facing the first substrate below the first substrate, forming a particle for heating and diffusing the structure of the first substrate to from a spherical particle from the diffused material of the structure, and collecting a particle for collecting particles by landing the spherical particles falling from the first substrate on the second substrate.

A particle manufacturing method is disclosed. A particle manufacturing method according to one aspect of the present disclosure as a method of forming a spherical particle may include forming a structure for forming a structure of a protruding shape with a material composing of the particle on a first substrate, disposing substrates for disposing the first substrate such that the structure faces downward and disposing a second substrate facing the first substrate below the first substrate, forming a particle for heating and diffusing the structure of the first substrate to from a spherical particle from the diffused material of the structure, and collecting a particle for collecting particles by landing the spherical particles falling from the first substrate on the second substrate.