In order to understand the molecules mechanism of ion irradiation,which has been widely used in many fields such as cancer therapy,uracil,one of the bases of nucleic acid.was chosen in the low energy ion radiolysis re...In order to understand the molecules mechanism of ion irradiation,which has been widely used in many fields such as cancer therapy,uracil,one of the bases of nucleic acid.was chosen in the low energy ion radiolysis research.The solid uracil films with mass thickness of 0.314mg/cm^2 were irradiated by 200keV H^+ ions .The experimental results show that 200keV H^+ ions are effective in decomposition of uracil molecules.One of the decomposition products,5,6-dihydro-uracil,was separated by high performance liquid chromatograph (HPLC) and detected using an UV-light detector.Its yield increases first but then decreases as the ion dose increasing.In addition,the mechanism of uracil decomposition and 5,6-dihydro-uracil formation was also disucssed.展开更多
Hydrogen distribution and content in diamond films deposited by DC arcjetunder gas recycling mode was evaluated by nuclear reaction analysis (NRA). The films werecharacterized using scanning electron microscopy, X-ray...Hydrogen distribution and content in diamond films deposited by DC arcjetunder gas recycling mode was evaluated by nuclear reaction analysis (NRA). The films werecharacterized using scanning electron microscopy, X-ray diffraction and Raman spectrometry. The NRAresults show that the hydrogen content in diamond films was approximately 0.6% (substratetemperature 770℃), and strongly depended on the substrate temperature. It was that the hydrogencontent increased with the increase of the substrate temperature. The possibility of hydrogentrapping in the films was also discussed.展开更多
In image reconstruction algorithms, the choices of filter functions and interpolating functions are very important for the computational speed and the quality of the image reconstructed, especially, for fan-beam geome...In image reconstruction algorithms, the choices of filter functions and interpolating functions are very important for the computational speed and the quality of the image reconstructed, especially, for fan-beam geometry, the occurrence of the singular integral operator may lead tosome great oscillations compared to the original image. In this paper we will give a direct convolu-tion algorithm which needs not the complex computations occuring in the Fourier transform, then using a circle integral we obtain a stable computational program. Different from all other previouswindow functions used by many pioneer researchers, in our algorithm we choose a window func tion similar to Gabor's window function e-x^2/2 , which can be regarded as the approximation to the inverse Fourier transform of a locally integrable frequency function. Also we point out that such reconstruction algorithm procedures can be used to deal with the SPECT projection data with constant attenuation.展开更多
文摘In order to understand the molecules mechanism of ion irradiation,which has been widely used in many fields such as cancer therapy,uracil,one of the bases of nucleic acid.was chosen in the low energy ion radiolysis research.The solid uracil films with mass thickness of 0.314mg/cm^2 were irradiated by 200keV H^+ ions .The experimental results show that 200keV H^+ ions are effective in decomposition of uracil molecules.One of the decomposition products,5,6-dihydro-uracil,was separated by high performance liquid chromatograph (HPLC) and detected using an UV-light detector.Its yield increases first but then decreases as the ion dose increasing.In addition,the mechanism of uracil decomposition and 5,6-dihydro-uracil formation was also disucssed.
文摘Hydrogen distribution and content in diamond films deposited by DC arcjetunder gas recycling mode was evaluated by nuclear reaction analysis (NRA). The films werecharacterized using scanning electron microscopy, X-ray diffraction and Raman spectrometry. The NRAresults show that the hydrogen content in diamond films was approximately 0.6% (substratetemperature 770℃), and strongly depended on the substrate temperature. It was that the hydrogencontent increased with the increase of the substrate temperature. The possibility of hydrogentrapping in the films was also discussed.
文摘In image reconstruction algorithms, the choices of filter functions and interpolating functions are very important for the computational speed and the quality of the image reconstructed, especially, for fan-beam geometry, the occurrence of the singular integral operator may lead tosome great oscillations compared to the original image. In this paper we will give a direct convolu-tion algorithm which needs not the complex computations occuring in the Fourier transform, then using a circle integral we obtain a stable computational program. Different from all other previouswindow functions used by many pioneer researchers, in our algorithm we choose a window func tion similar to Gabor's window function e-x^2/2 , which can be regarded as the approximation to the inverse Fourier transform of a locally integrable frequency function. Also we point out that such reconstruction algorithm procedures can be used to deal with the SPECT projection data with constant attenuation.
