Five kinds of simulated body fluids were prepared according to the Ca 2+ ions concentration in body fluids of human, dog, pig, rabbit and monkey so that the different biological environments in different animals were simulated. Results showed that Ca 2+ can induce bone-like apatite formation in a dose-dependent manner; there is a threshold of Ca 2+ local concentration for the formation of bone-like apatite. The threshold of Ca 2+ for bone-like apatite formation in static stimulated body fluid (SBF) is different from dynamic SBF. The threshold of static SBF is lower than that of dynamic SBF. The threshold of Ca 2+ local concentration is 0.2459g/L in static SBF and 0.3392g/L in dynamic SBF.

Drilling is a particularly complicated machining process, and it becomes much more complicated when the workpiece is printed circuit boards (PCBs). PCB is composite materials with anisotropy. Even a small defect in PCB may cause great losses. Both the drilling process and PCB structure design have been researched by many scholars. But the investigations into the drilling processes of PCB are not systematic. The present review article address the report about tool materials and geometrics, cutting force, cutting temperature, radial run-out and damages occurring in drilling processes. And as a conclusion, some of these critical issues are proposed to meet the challenges in analysis and optimization for PCB drilling.

Drilling force and temperature of tibia at the high speed drilling for improving the design of surgical drills are very important. In this paper we describe experiments using pig tibia bones, measuring the drilling force and temperature of a new design of drill bit and compare the results against a twist drill. The result shows that the drilling force and temperature are affected by the feed rate and drilling speed, which vary with the drilling depth into the bone. The new surgical drill with three top cutting edges can achieve lower temperature below 47oC and lower drilling force than with the stainless steel twist drill and carbide twist drill.

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This paper presents a review of the authors' investigation in the cutting processes of diabase and granite. The formation of crushed zone and the propagation of microcracks and cracks under different cutting conditions have been observed in detail by means of a workshop microscope and a polarization microscope. The fracture mechanism is analyzed by measuring the cutting strain field using laser speckle interferometry and comparing the fractography of the cutting chips with those of the samples of tensile test and shear test. The cutting mechanism models of diabase and granite are proposed respectively.