The nature of the native oxides formed on the surface layer of amorphous alloy Ni_(64)P_(20)Fe_(16)has been studied by X-ray photoelectron spectroscopy (XPS)and Auger electron spectroscopy(AES)with depth profiling by ...The nature of the native oxides formed on the surface layer of amorphous alloy Ni_(64)P_(20)Fe_(16)has been studied by X-ray photoelectron spectroscopy (XPS)and Auger electron spectroscopy(AES)with depth profiling by ion bombardment.There are great distinctions in compositions and chemical states between the surface layer and the bulk.The main constituents Ni,P and Fe are lower in the sur- face layer,and they are mostly in oxidized states, whereas C,O and N are enriched in the surface lay- er.The thickness of surface oxide layer is approximately 20 nm,this layer was assumed to be of great significance to various properties of amor- phous alloy Ni_(64)P_(20)Fe_(16),expecially to the chemical and catalytic properties.Experiments proved that transitional element Fe cannot improve oxidation resistance of the amorphous Ni-P system.展开更多
Background In the past 20 years, non-invasive coronary imaging technology has developed rapidly, the 16- multidetector CT has accumulated abundant experiences for the clinical application of 64-multidetector CT. We ev...Background In the past 20 years, non-invasive coronary imaging technology has developed rapidly, the 16- multidetector CT has accumulated abundant experiences for the clinical application of 64-multidetector CT. We evaluated the result of 706 patients being studied by the 16-multidetetor coronary angiography, providing the evidences for early diagnosis and reliable evaluation. Methods Seven hundred and six patients underwent 16- multideteeor coronary angiography, among which 537 received regular doses of [3 receptor blockers, maintaining their heart rates amidst 65 ± 10beats/min （bpm）. The retrospective ECG gating was used to generate images （slice thickness 1125 mm, pitch 0.257：1）. The contrast injection was 115-2 mm/kg bolus of nonionie contrast material （300 or 370 mg of iodine per milliliter） at flow rate 3-4 mL/s. After injection of contrast material, the patients were instructed to breath-hold for 20 seconds to ensure clear visualization and reliable evaluation of the main coronary artery and its branches （left main coronary, left anterior descending, left circumflex, and right coronary）. The postprocessing was done by volume rendering （VR）, Maximum intensity projection （MIP）, and Virtual Endoscopy （VE）. Result Two thousand five hundred and fifty six coronary arteries were included in the studies. Sensitivity, specificity, accuracy, and positive and negative predictive values for the whole study group were 96 %, 88 %, 89 %, 91%, 93 %, respectively. Significant stenosis （diameter stenosis 1〉50 %） were detected in 936 of 2556 arteries, including calcified stenosis 773/936 （82.59 %）, noncalcified plaque stenosis 163/936 （17.41%）, single branches significant stenosis 612/936 （65.38 %）, two-branch significant stenosis 237/936 （22.32 %）, more than three branches significant stenosis 113/936 （12.07 %）. Conclusions The technically improved 16-muhideetor CT, with better heart rate control and scanning techniques, permits satisfactory visualization of the main coronary artery and its branches. It also serves as a valuable tool in screening of coronary artery disease and follow-up of coronary bypass graft and stent.展开更多
文摘The nature of the native oxides formed on the surface layer of amorphous alloy Ni_(64)P_(20)Fe_(16)has been studied by X-ray photoelectron spectroscopy (XPS)and Auger electron spectroscopy(AES)with depth profiling by ion bombardment.There are great distinctions in compositions and chemical states between the surface layer and the bulk.The main constituents Ni,P and Fe are lower in the sur- face layer,and they are mostly in oxidized states, whereas C,O and N are enriched in the surface lay- er.The thickness of surface oxide layer is approximately 20 nm,this layer was assumed to be of great significance to various properties of amor- phous alloy Ni_(64)P_(20)Fe_(16),expecially to the chemical and catalytic properties.Experiments proved that transitional element Fe cannot improve oxidation resistance of the amorphous Ni-P system.
文摘Background In the past 20 years, non-invasive coronary imaging technology has developed rapidly, the 16- multidetector CT has accumulated abundant experiences for the clinical application of 64-multidetector CT. We evaluated the result of 706 patients being studied by the 16-multidetetor coronary angiography, providing the evidences for early diagnosis and reliable evaluation. Methods Seven hundred and six patients underwent 16- multideteeor coronary angiography, among which 537 received regular doses of [3 receptor blockers, maintaining their heart rates amidst 65 ± 10beats/min （bpm）. The retrospective ECG gating was used to generate images （slice thickness 1125 mm, pitch 0.257：1）. The contrast injection was 115-2 mm/kg bolus of nonionie contrast material （300 or 370 mg of iodine per milliliter） at flow rate 3-4 mL/s. After injection of contrast material, the patients were instructed to breath-hold for 20 seconds to ensure clear visualization and reliable evaluation of the main coronary artery and its branches （left main coronary, left anterior descending, left circumflex, and right coronary）. The postprocessing was done by volume rendering （VR）, Maximum intensity projection （MIP）, and Virtual Endoscopy （VE）. Result Two thousand five hundred and fifty six coronary arteries were included in the studies. Sensitivity, specificity, accuracy, and positive and negative predictive values for the whole study group were 96 %, 88 %, 89 %, 91%, 93 %, respectively. Significant stenosis （diameter stenosis 1〉50 %） were detected in 936 of 2556 arteries, including calcified stenosis 773/936 （82.59 %）, noncalcified plaque stenosis 163/936 （17.41%）, single branches significant stenosis 612/936 （65.38 %）, two-branch significant stenosis 237/936 （22.32 %）, more than three branches significant stenosis 113/936 （12.07 %）. Conclusions The technically improved 16-muhideetor CT, with better heart rate control and scanning techniques, permits satisfactory visualization of the main coronary artery and its branches. It also serves as a valuable tool in screening of coronary artery disease and follow-up of coronary bypass graft and stent.
