Measurements of the cosmic-ray hydrogen and helium spectra at energies from 20 to 800 TeV are presented. The experiments were performed on a series of twelve balloon Ñights, including several long duration Australia to South America and Antarctic circumpolar Ñights. No clear evidence is seen for a spectral break. Both the hydrogen and the helium spectra are consistent with power laws over the entire energy range, with integral spectral indices 1.80^0.04 and for the protons and helium, respec-1.68~0 .06 0.04 tively. The results are fully consistent with expectations based on supernova shock acceleration coupled with a "" leaky box ÏÏ model of propagation through the Galaxy.

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Titanium (Ti) has been used for many biomedical applications. Surface characteristics of titanium devices are critical to their success. In this study, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to analyse Ti surfaces prior to immersion in alpha-modification of Eagle's medium (¢-MEM). The ionic constituents deposited onto Ti surfaces after in vitro exposure to ~-MEM were investigated using XPS and Fourier transform infrared spectroscopy (FTIR). Surface studies revealed an amorphous oxide layer on the Ti surface, with a chemistry similar to TiO2. However, after exposure to the physiologic solution for 12 days, dynamic changes in surface chemistry were observed. Ions such as phosphorus (P) and calcium (Ca) were increasingly deposited as amorphous fine crystalline calciumphosphate (Ca-P) compounds, having a Ca/P ratio of 1.2 and a chemistry similar to brushite.

Surgical implant finishing and sterilization procedures were investigated to determine surface characteristics of unalloyed titanium (Ti). All specimens initially were cleaned with phosphoric acid and divided into five groups for comparisons of different surface treatments (C = cleaned as above, no further treatment; CP = C and passivated in nitric acid; CPS = CP and dry-heat sterilized; CPSS = CPS and resterilized; CS = C and dry-heat sterilized). Auger (AES), X-ray photoelectron (XPS), and Raman spectroscopic methods were used to examine surface compositions. The surface oxides formed by all treatments primarily were TiO 2 , with some Ti 2 O 3 and possibly TiO. Significant concentrations of carbonaceous substances also were observed. The cleaning procedure alone resulted in residual phosphorus, primarily as phosphate groups along with some hydrogen phosphates. A higher percentage of physisorbed water appeared to be associated with the phosphorus. Passivation (with HNO 3 ) alone removed phosphorus from the surface; specimens sterilized without prior passivation showed the thickest oxide and phosphorus profiles, suggesting that passivation alters the oxide characteristics either directly by altering the oxide structure or indirectly by removing moieties that alter the oxide. Raman spectroscopy showed no crystalline order in the oxide. Carbon, oxygen, phosphorus, and nitrogen presence were found to correlate with previously determined surface energy.