Cross-sectional investigation is an important method to study ion irradiation effects in the depth direction. In this study, 2 Me V H^+was implanted in 6 H-SiC single crystals to investigate the effects of light ion i...Cross-sectional investigation is an important method to study ion irradiation effects in the depth direction. In this study, 2 Me V H^+was implanted in 6 H-SiC single crystals to investigate the effects of light ion irradiation on SiC. Raman spectroscopy and scanning electronic microscopy(SEM) were carried out on crosssectional samples to reveal the in-depth damage states and dopant behavior. The most damaged region is a little shallower than that predicted by the SRIM procedure,owing to the uncertainty in SRIM simulations. Layered structures representing zones of varying damage after2 MeV H ion irradiation are clearly observed. Two bands are observed in SEM images, of which on band corresponds to the damage peak, while the other band at the end of the H ion-affected area is probably a result of H diffusion propelled by a hydrogen-rich layer during irradiation.A charge accumulation effect related with conductivity on the sample surfaces during SEM tests is observed in theH-implanted area. A model is proposed to explain these phenomena.展开更多
Elastic electron scattering on the exotic light nucleus 28S is investigated in the plane wave Born approximation. The variation of the squared form factors of 28S with momentum transfer is compared with that of 32S. I...Elastic electron scattering on the exotic light nucleus 28S is investigated in the plane wave Born approximation. The variation of the squared form factors of 28S with momentum transfer is compared with that of 32S. It is found that the behavior of the form factors near the second minimum (with a moderate momentum transfer) is sensitive to the alteration of the charge density distribution of halo protons in 28S. This indicates that elastic electron scattering can be a good probe of the structure of proton-halo nuclei.展开更多
The elastic scattering of p-^14Be system at Elab = 200 MeV is evaluated within the relativistic impulse approximation. We discuss the effects of the halo neutrons on the three observables of the elastic scattering sys...The elastic scattering of p-^14Be system at Elab = 200 MeV is evaluated within the relativistic impulse approximation. We discuss the effects of the halo neutrons on the three observables of the elastic scattering system, such as differential cross section dσ/ dΩ, analyzing power Ay and spin rotation Q. The results of the three observables of the elastic scattering of p-^14Be system are compared with those of p-^12C and p-^16O systems at the same energy as E1ab = 200 MeV. We have found that in the small angular region the Ay and Q, as well as dσ/dΩ, are quite sensitive to the nucleon density distributions on the surface of the target nucleus and offer some unique behaviors of halo nuclei.展开更多
Probing in-medium nucleon-nucleon （NN） cross section σ1/NN（α） in heavy ion collisions has been investigated by means of the isospin-dependent quantum molecular dynamics （IQMD） with the isospin- and momentum-de...Probing in-medium nucleon-nucleon （NN） cross section σ1/NN（α） in heavy ion collisions has been investigated by means of the isospin-dependent quantum molecular dynamics （IQMD） with the isospin- and momentum-dependent interaction （IMDI（T））. It is found that there are the very obvious medium effect and the sensitive isospin-dependence of nuclear stopping R on the in-medium NN cross section α1/NN（α） in the nuclear reactions induced by halo-neutron projectile and the same-mass stable projectile. However, R induced by the neutron-halo projectile is obviously lower than that induced by the corresponding stable projectile. In particular, there is a very obvious dependence of R on the medium effect of σ1/NN（α） in the whole beam energy region for the above two kinds of projectiles. Therefore, the comparison between the results of R＇s in the reactions induced by the neutron-halo projectile and the corresponding same-mass stable projectile is a more favourable probe for extracting the information of σ1/NN（α） because of adding a new judgement.展开更多
The nonradiative charge-transfer cross sections for protons colliding with Rb（5s） atoms are calculated by using the quantum-mechanical molecularorbital close-coupling method in an energy range of 10-a keV-10 keV. Th...The nonradiative charge-transfer cross sections for protons colliding with Rb（5s） atoms are calculated by using the quantum-mechanical molecularorbital close-coupling method in an energy range of 10-a keV-10 keV. The total and state-selective charge-transfer cross sections are in good agreement with the experimental data in the relatively low energy region. The importance of rotational coupling for chargetransfer process is stressed. Compared with the radiative charge-transfer process, nonradiative charge transfer is a dominant mechanism at energies above 15 eV. The resonance structures of state-selective charge-transfer cross sections arising from the competition among channels are analysed in detail. The radiative and nonradiative1 charge-transfer rate coefficients from low to high temperature are presented.展开更多
Available nuclear data(absorption cross sections,angular distributions,energyspectra,double differential cross sections of single particle emission and global sets of cross sec-tions of <sup>56,57</sup>Fe)...Available nuclear data(absorption cross sections,angular distributions,energyspectra,double differential cross sections of single particle emission and global sets of cross sec-tions of <sup>56,57</sup>Fe)are collected,evaluated and calculated by the new theoretical program.Goodagreements are obtained between the experimental data and the calculated data,respectively.展开更多
Background: Gastroesophageal reflux disease (GERD) is a prevalent disease in Western countries. Despite effective treatment modalities, in some patients total symptom control is not achieved in clinical practice. A cr...Background: Gastroesophageal reflux disease (GERD) is a prevalent disease in Western countries. Despite effective treatment modalities, in some patients total symptom control is not achieved in clinical practice. A cross-sectional study was designed to assess primary care practitioners’ views on the effectiveness of proton pump inhibitors (PPI) as monotherapy in the control of the most common symptoms of GERD (heartburn and regurgitation), as well as to determine the level of implementation of the “combined therapy” (PPI + alginate-antacids). Methods: A questionnaire on different aspects of the management of GERD was completed by 1491 primary care physicians. The questionnaire was composed of 11 close-ended questions with one-choice answer, with a total of 52 items, covering the main data from patients presenting with GERD. Results: Treatment with PPI alone was mostly considered insufficient for the control of GERD symptoms. The combined treatment of PPI + alginate-antacids was used for 37% and 21% of physicians for treating heart-burn and regurgitation, respectively. A better control of symptoms, an increase in the onset of action and to reduce nocturnal acid breakthrough were the most frequently argued reasons for the use of PPI + alginate-antacids. A high percentage of participants believed that treatment with PPI alone was insufficient for the control of symptoms and 39.8% of physicians reported the persistence of heartburn, 38.6% the persistence of regurgitation and 43.2% the persistence of epigastric discomfort in more than 25% of their patients treated with PPI as monotherapy. The most common schedule for the use of the antacid medication was on demand. Conclusions: Spanish primary care physicians consider that a high proportion of GERD patients continue to suffer from symptoms during PPI treatment alone. Ondemand “combined therapy” (PPI + antacid) is considered an efficient option to control reflux symptoms still troublesome in patients with PPI treatment alone.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11705169,91426304 and 91226202)
文摘Cross-sectional investigation is an important method to study ion irradiation effects in the depth direction. In this study, 2 Me V H^+was implanted in 6 H-SiC single crystals to investigate the effects of light ion irradiation on SiC. Raman spectroscopy and scanning electronic microscopy(SEM) were carried out on crosssectional samples to reveal the in-depth damage states and dopant behavior. The most damaged region is a little shallower than that predicted by the SRIM procedure,owing to the uncertainty in SRIM simulations. Layered structures representing zones of varying damage after2 MeV H ion irradiation are clearly observed. Two bands are observed in SEM images, of which on band corresponds to the damage peak, while the other band at the end of the H ion-affected area is probably a result of H diffusion propelled by a hydrogen-rich layer during irradiation.A charge accumulation effect related with conductivity on the sample surfaces during SEM tests is observed in theH-implanted area. A model is proposed to explain these phenomena.
基金supported by the National Natural Science Foundation of China(Grant No.10125521)by the 973 National Major State Basic Research and Development of China(Grant No.G2000077400)by the Research Fund for the Doctoral Program of Higher Education under contract No.20010284036.
文摘Elastic electron scattering on the exotic light nucleus 28S is investigated in the plane wave Born approximation. The variation of the squared form factors of 28S with momentum transfer is compared with that of 32S. It is found that the behavior of the form factors near the second minimum (with a moderate momentum transfer) is sensitive to the alteration of the charge density distribution of halo protons in 28S. This indicates that elastic electron scattering can be a good probe of the structure of proton-halo nuclei.
基金The project supported by National Natural Science Foundation of China under Grant No. 10125521, the 973 State Key Basic Research and Development Program of China under Grant No. G2000077400, the CAS Knowledge Innovation Project under Grant No. KJCX2-SW- N02, and the Research Fand of Higher Education under Grant No. 20010284036
文摘The elastic scattering of p-^14Be system at Elab = 200 MeV is evaluated within the relativistic impulse approximation. We discuss the effects of the halo neutrons on the three observables of the elastic scattering system, such as differential cross section dσ/ dΩ, analyzing power Ay and spin rotation Q. The results of the three observables of the elastic scattering of p-^14Be system are compared with those of p-^12C and p-^16O systems at the same energy as E1ab = 200 MeV. We have found that in the small angular region the Ay and Q, as well as dσ/dΩ, are quite sensitive to the nucleon density distributions on the surface of the target nucleus and offer some unique behaviors of halo nuclei.
基金Project supported by the State Key Development Program for Basic Research of China （Grant No G2000077400）, the Major Program of the National Natural Science Foundation of China （Grant Nos 10435080 and 105350101）, the National Natural Science Foundation of China （Grant Nos 10447006 and 10575075）, the CAS Knowledge Innovation Project Program （Grant No KJCX2-SW-N02）.
文摘Probing in-medium nucleon-nucleon （NN） cross section σ1/NN（α） in heavy ion collisions has been investigated by means of the isospin-dependent quantum molecular dynamics （IQMD） with the isospin- and momentum-dependent interaction （IMDI（T））. It is found that there are the very obvious medium effect and the sensitive isospin-dependence of nuclear stopping R on the in-medium NN cross section α1/NN（α） in the nuclear reactions induced by halo-neutron projectile and the same-mass stable projectile. However, R induced by the neutron-halo projectile is obviously lower than that induced by the corresponding stable projectile. In particular, there is a very obvious dependence of R on the medium effect of σ1/NN（α） in the whole beam energy region for the above two kinds of projectiles. Therefore, the comparison between the results of R＇s in the reactions induced by the neutron-halo projectile and the corresponding same-mass stable projectile is a more favourable probe for extracting the information of σ1/NN（α） because of adding a new judgement.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10979007,11025417,11179041,and 11004014)the NSAF (Grant No. 10876043)
文摘The nonradiative charge-transfer cross sections for protons colliding with Rb（5s） atoms are calculated by using the quantum-mechanical molecularorbital close-coupling method in an energy range of 10-a keV-10 keV. The total and state-selective charge-transfer cross sections are in good agreement with the experimental data in the relatively low energy region. The importance of rotational coupling for chargetransfer process is stressed. Compared with the radiative charge-transfer process, nonradiative charge transfer is a dominant mechanism at energies above 15 eV. The resonance structures of state-selective charge-transfer cross sections arising from the competition among channels are analysed in detail. The radiative and nonradiative1 charge-transfer rate coefficients from low to high temperature are presented.
基金The project supported by China Nuclear Data Center
文摘Available nuclear data(absorption cross sections,angular distributions,energyspectra,double differential cross sections of single particle emission and global sets of cross sec-tions of <sup>56,57</sup>Fe)are collected,evaluated and calculated by the new theoretical program.Goodagreements are obtained between the experimental data and the calculated data,respectively.
文摘Background: Gastroesophageal reflux disease (GERD) is a prevalent disease in Western countries. Despite effective treatment modalities, in some patients total symptom control is not achieved in clinical practice. A cross-sectional study was designed to assess primary care practitioners’ views on the effectiveness of proton pump inhibitors (PPI) as monotherapy in the control of the most common symptoms of GERD (heartburn and regurgitation), as well as to determine the level of implementation of the “combined therapy” (PPI + alginate-antacids). Methods: A questionnaire on different aspects of the management of GERD was completed by 1491 primary care physicians. The questionnaire was composed of 11 close-ended questions with one-choice answer, with a total of 52 items, covering the main data from patients presenting with GERD. Results: Treatment with PPI alone was mostly considered insufficient for the control of GERD symptoms. The combined treatment of PPI + alginate-antacids was used for 37% and 21% of physicians for treating heart-burn and regurgitation, respectively. A better control of symptoms, an increase in the onset of action and to reduce nocturnal acid breakthrough were the most frequently argued reasons for the use of PPI + alginate-antacids. A high percentage of participants believed that treatment with PPI alone was insufficient for the control of symptoms and 39.8% of physicians reported the persistence of heartburn, 38.6% the persistence of regurgitation and 43.2% the persistence of epigastric discomfort in more than 25% of their patients treated with PPI as monotherapy. The most common schedule for the use of the antacid medication was on demand. Conclusions: Spanish primary care physicians consider that a high proportion of GERD patients continue to suffer from symptoms during PPI treatment alone. Ondemand “combined therapy” (PPI + antacid) is considered an efficient option to control reflux symptoms still troublesome in patients with PPI treatment alone.
