Abstract: Embodiments include a bar for a chain saw that is equipped with one or more oil channels that run along the length of the bar. Each oil channel receives oil at a first end, which exits the oil channel at an oil exit aperture at a second end of the channel. The oil exit aperture of one of the channels is positioned along the side of a bar groove, through which runs the saw chain, proximate to the cutting area of the bar to lubricate the saw chain just prior to the cutting area. A second channel may have an oil exit aperture proximate to the nose of the bar, to lubricate a sprocket wheel in the nose of the bar.

Abstract: A compositionally-graded, strain relaxed Si1-xGex (0<x<1) material having a surface roughness of less than 1 nm. In a preferred aspect, the compositionally-graded material is Si1-xGex (0<x<0.3) material having a threading dislocation density <1×105 defects/cm2 of surface area. The compositionally-graded material is readily formed by vapor deposition or other suitable technique, in which the temperature is selectively modulated during the growth process, optionally with modulation of germanium precursor flow rate, to produce a low surface roughness, low threading dislocation defect density graded silicon-germanium film suitable for forming strained heterostructures such as Si1-xGex/Si.