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The pure titanium disks were divided into three groups and etched for 30 minutes with HNO3, hot H2SO4/H2O2 or hot H2SO4/HCl respectively. The treated disks were studied and analyzed with scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The disks etched with HNO3 had a smooth surface, while those etched with hot H2SO4/H2O2 or hot H2SO4/HCl had rough surfaces, and the surface etched with hot H2SO4/HCl had larger micropores. The XPS analysis demonstrated that the main elements of the surface in three groups were titanium, oxygen and carbon. The carbon concentration was the lowest on the surface etched with hot H2SO4/H2O2 and the highest on that etched with hot H2SO4/HCl. The substances were TiO2, Ti2O3, TiO and metal Ti on the surface etched with HNO3 or hot H2SO4/H2O2. Only TiO2 was detected on the surface etched with hot H2SO4/HCl.

The high SNR (Signal-to-Noise) spectra from 20 cases of gastric carcinoma and normal mucosa were obtained by confocal Raman microspectroscopy. Consistent spectral features were observed at different sites of one tissue slice for both typical tissues. Raman spectra of normal gastric mucosa shows two peaks which are assigned to amide I vibration of proteins in 1640-1670(cm(-1)) spectral region. However, in gastric carcinoma, only one peak of amino I vibrational mode of proteins can be observed. The obviously different spectral characters of the two types of tissues are in accordance to clinicopathologic diagnosis. The result shows Raman spectroscopy might be a potential method in the diagnosis of gastric carcinoma.