During high power laser welding, the amount of energy reaching the workpiece, the weld penetration and the geometry of the welds are strongly affected by the laser induced plasma. Light emissions during welding were r...During high power laser welding, the amount of energy reaching the workpiece, the weld penetration and the geometry of the welds are strongly affected by the laser induced plasma. Light emissions during welding were recorded by a spectrometer. Based on the collected spectroscopic data, the electron density and the temperature of plasma were calculated using the relative intensity method. Several relationships between weld penetrations and electron density are given.展开更多
/h/ is described differently by different researchers. While some argue that /h/ is a glottal fricative, others argue that it is the voiceless counterpart of the following vowel, yet others argue that /h/ is a glide o.../h/ is described differently by different researchers. While some argue that /h/ is a glottal fricative, others argue that it is the voiceless counterpart of the following vowel, yet others argue that /h/ is a glide or an approximant. However, de- tailed acoustic studies focusing on /h/ are very limited. This study aims to describe the spectrographic characteristics of /h/ in Turkish. Test words consisted of 48 monosyllabic and disyllabic words containing /h/ which was followed by eight Turkish vowels. Totally 1440 tokens were analyzed. After segmentation, /h/ was classified based on its spectrographic characteristics: 1) segment exhibiting formants, 2) segment exhibiting frication (but no formants) with energy in lower frequencies and 3) segment exhibiting almost no energy. In order to find out if there is a significant difference among these three categories, Chi-square test was applied. The spectrographic characteristics of /h/ in Turkish suggest that it is more like the voiceless version of the surrounding vowels, significantly when it is in syllable initial position and the preceding vowel when in syllable final position.展开更多
AIM: To investigate the protective mechanism of Gingko Biloba extract(EGb761) on the ability of retinal pigment epithelial(RPE) cells to resist light-induced damage in a comparative proteomics study. · METHODS: H...AIM: To investigate the protective mechanism of Gingko Biloba extract(EGb761) on the ability of retinal pigment epithelial(RPE) cells to resist light-induced damage in a comparative proteomics study. · METHODS: Human RPE cells(ARPE-19) were randomly distributed to one of three groups: normal control(NC group) and light-damaged model without or with EGb761 group(M and ME groups,respectively). The light-damaged model was formed by exposing to white light(2 200 ±300)lx for 6h. The RPE cells in ME group were conducted with EGb761(100μg/mL) before light exposure. The soluble cellular proteins extracting from each groups were separated by two-dimensional electrophoresis and stained by silver staining. Different proteins in the profiles of the gels were analyzed by Image Master Software. Two-fold expressing protein spots were identified by Matrix-assisted laser desorption/ ionization tandem time-of-flight(MALDI-TOF/TOF) mass spectrometry. ·RESULTS: NC,M and ME groups displayed 1 892±71,2 145 ±23 and 2 216 ±85 protein spots,respectively. We identified 33 proteins with different expression levels between the NC and M groups,25 proteins between the M and ME groups,and 11 proteins between the NC and ME groups. MALDI-TOF/TOF mass spectrometry successfully identified 16 proteins,including metabolic enzymes,cytoskeletal proteins,anti-oxidation proteins,and others. ·CONCLUSION: Differences in some important proteins,such as cathepsin B,heat shock protein,and cytochrome C reductase,indicated that multiple pathways may be induced in light-damaged RPE cells and the protective effect of EGb761.展开更多
The main goal of the gamma-ray spectrometer（GRS） onboard Chang＇E1（CE-1） is to acquire global maps of elemental abundances and their distributions on the moon,since such maps will significantly improve our underst...The main goal of the gamma-ray spectrometer（GRS） onboard Chang＇E1（CE-1） is to acquire global maps of elemental abundances and their distributions on the moon,since such maps will significantly improve our understanding of lunar formation and evolution.To derive the elemental maps and enable research on lunar formation and evolution,raw data that are received directly from the spacecraft must be converted into time series corrected gamma-ray spectra.The data correction procedures for the CE-1 GRS time series data are thoroughly described.The processing procedures to create the time series gamma-ray spectra described here include channel processing,optimal data selection,energy calibration,gain correction,dead time correction,geometric correction,orbit altitude normalization,eliminating unusable data and galactic cosmic ray correction.Finally,descriptions are also given on data measurement uncertainties,which will help the interested scientists to understand and estimate various uncertainties associated with the above data processing.展开更多
The left-hand side of the auroral hiss emission observed by Galileo has a frequency time profile shaped very similar to the funnel shape observed in the Earth＇s auroral region. This close similarity indicates that we...The left-hand side of the auroral hiss emission observed by Galileo has a frequency time profile shaped very similar to the funnel shape observed in the Earth＇s auroral region. This close similarity indicates that we can use the theory of whistler- mode propagation near the resonance cone to locate the emission source. The general characteristics of the whistler mode are discussed. Then the position of the emission source is investigated using a geometrical method that takes into account the trajectory of Galileo. Initially a point source is assumed. Then the possibility of a sheet source aligned along the magnetic field lines which tigated. Both types of sources show that the close to the surface of Io. are tangent to the surface of Io is inves- whistler mode radiation originates veryclose to the surface of Io.展开更多
文摘During high power laser welding, the amount of energy reaching the workpiece, the weld penetration and the geometry of the welds are strongly affected by the laser induced plasma. Light emissions during welding were recorded by a spectrometer. Based on the collected spectroscopic data, the electron density and the temperature of plasma were calculated using the relative intensity method. Several relationships between weld penetrations and electron density are given.
文摘/h/ is described differently by different researchers. While some argue that /h/ is a glottal fricative, others argue that it is the voiceless counterpart of the following vowel, yet others argue that /h/ is a glide or an approximant. However, de- tailed acoustic studies focusing on /h/ are very limited. This study aims to describe the spectrographic characteristics of /h/ in Turkish. Test words consisted of 48 monosyllabic and disyllabic words containing /h/ which was followed by eight Turkish vowels. Totally 1440 tokens were analyzed. After segmentation, /h/ was classified based on its spectrographic characteristics: 1) segment exhibiting formants, 2) segment exhibiting frication (but no formants) with energy in lower frequencies and 3) segment exhibiting almost no energy. In order to find out if there is a significant difference among these three categories, Chi-square test was applied. The spectrographic characteristics of /h/ in Turkish suggest that it is more like the voiceless version of the surrounding vowels, significantly when it is in syllable initial position and the preceding vowel when in syllable final position.
基金Supported by National Natural Science Foundation of China(No.30500676)
文摘AIM: To investigate the protective mechanism of Gingko Biloba extract(EGb761) on the ability of retinal pigment epithelial(RPE) cells to resist light-induced damage in a comparative proteomics study. · METHODS: Human RPE cells(ARPE-19) were randomly distributed to one of three groups: normal control(NC group) and light-damaged model without or with EGb761 group(M and ME groups,respectively). The light-damaged model was formed by exposing to white light(2 200 ±300)lx for 6h. The RPE cells in ME group were conducted with EGb761(100μg/mL) before light exposure. The soluble cellular proteins extracting from each groups were separated by two-dimensional electrophoresis and stained by silver staining. Different proteins in the profiles of the gels were analyzed by Image Master Software. Two-fold expressing protein spots were identified by Matrix-assisted laser desorption/ ionization tandem time-of-flight(MALDI-TOF/TOF) mass spectrometry. ·RESULTS: NC,M and ME groups displayed 1 892±71,2 145 ±23 and 2 216 ±85 protein spots,respectively. We identified 33 proteins with different expression levels between the NC and M groups,25 proteins between the M and ME groups,and 11 proteins between the NC and ME groups. MALDI-TOF/TOF mass spectrometry successfully identified 16 proteins,including metabolic enzymes,cytoskeletal proteins,anti-oxidation proteins,and others. ·CONCLUSION: Differences in some important proteins,such as cathepsin B,heat shock protein,and cytochrome C reductase,indicated that multiple pathways may be induced in light-damaged RPE cells and the protective effect of EGb761.
基金supported by the National High Technology Research and Development Program of China (Grant Nos. 2008AA12A212 and 2010AA122202)the National Natural Science Foundation of China (Grant Nos. 41040031 and 40904024)
文摘The main goal of the gamma-ray spectrometer（GRS） onboard Chang＇E1（CE-1） is to acquire global maps of elemental abundances and their distributions on the moon,since such maps will significantly improve our understanding of lunar formation and evolution.To derive the elemental maps and enable research on lunar formation and evolution,raw data that are received directly from the spacecraft must be converted into time series corrected gamma-ray spectra.The data correction procedures for the CE-1 GRS time series data are thoroughly described.The processing procedures to create the time series gamma-ray spectra described here include channel processing,optimal data selection,energy calibration,gain correction,dead time correction,geometric correction,orbit altitude normalization,eliminating unusable data and galactic cosmic ray correction.Finally,descriptions are also given on data measurement uncertainties,which will help the interested scientists to understand and estimate various uncertainties associated with the above data processing.
文摘The left-hand side of the auroral hiss emission observed by Galileo has a frequency time profile shaped very similar to the funnel shape observed in the Earth＇s auroral region. This close similarity indicates that we can use the theory of whistler- mode propagation near the resonance cone to locate the emission source. The general characteristics of the whistler mode are discussed. Then the position of the emission source is investigated using a geometrical method that takes into account the trajectory of Galileo. Initially a point source is assumed. Then the possibility of a sheet source aligned along the magnetic field lines which tigated. Both types of sources show that the close to the surface of Io. are tangent to the surface of Io is inves- whistler mode radiation originates veryclose to the surface of Io.
