The electrochemical behavior of X70 pipeline steel in (0.5mol·L-1 Na2CO3+1 mol·L-1 NaHCO3) solution was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). X-ray photoel...The electrochemical behavior of X70 pipeline steel in (0.5mol·L-1 Na2CO3+1 mol·L-1 NaHCO3) solution was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to analyze the composition and microstructure of the surface film. The results showed that there were two anodic peaks at -600 mV and -350 mV. The surface film formed at -600 mV mainly consisted of ferrous carbonates and ferrous hydroxycarbonates. It had a small reaction resistance. It was metastable and possessed poor protective property. Numerous pits and microcracks existed on the film, which could be the active paths for the initiation of stress corrosion cracking. The surface film formed at -350 mV, mainly consisted of ferric oxides. It has high reaction resistance and offered good protection for the substrate.展开更多
Schwannoma is a well-described,benign nerve sheath tumor of the soft tissue,but is rare in the gastrointestinal tract.Gastrointestinal schwannomas are often incidentally discovered as small polypoid intraluminal lesio...Schwannoma is a well-described,benign nerve sheath tumor of the soft tissue,but is rare in the gastrointestinal tract.Gastrointestinal schwannomas are often incidentally discovered as small polypoid intraluminal lesions.In this report,we describe the clinicopathologic and immunohistochemical features of a distinctive neural mucosal polyp composed of a diffuse cellular proliferation of uniform bland spindled cells in the lamina propria that entraps the colonic crypts.Immunohistochemical analysis revealed strong and diffuse positivity for the S-100 protein.To avoid confusion of these solitary colorectal polyps containing pure spindled Schwann cell proliferation in the lamina propria with neural lesions that have significant association with inherited syndromes,it is better to use the designation "mucosal Schwann hamartoma".展开更多
Due to the effect of Coulomb potential, the angular distribution of electron ionized in an elliptically polarized field presents an asymmetric structure, which is called "Coulomb asymmetry". In this paper, w...Due to the effect of Coulomb potential, the angular distribution of electron ionized in an elliptically polarized field presents an asymmetric structure, which is called "Coulomb asymmetry". In this paper, we study how to modulate the asymmetric degree of the electron angular distribution by using a semi-classical simplified tunneling model. It is found that the asymmetric structure is easily affected by three parameters: the ionization potential, the laser ellipticity,and the laser wavelength. However, the laser intensity has little effect on the asymmetric structure. To explain these phenomena we have derived an analytical formula, which clearly demonstrates the relationship between the asymmetric degree and these parameters. Moreover, we find that in elliptically polarized laser field only those electrons that are released in a certain narrow window of initial field phase are greatly effected by the Coulomb potential and play the key role in the formation of asymmetric structure. This study provides some reference values in the development of attoclock technique, which can be used to probe the tunneling process.展开更多
基金Supported by State Key Basic Research Plan (G19990650).
文摘The electrochemical behavior of X70 pipeline steel in (0.5mol·L-1 Na2CO3+1 mol·L-1 NaHCO3) solution was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to analyze the composition and microstructure of the surface film. The results showed that there were two anodic peaks at -600 mV and -350 mV. The surface film formed at -600 mV mainly consisted of ferrous carbonates and ferrous hydroxycarbonates. It had a small reaction resistance. It was metastable and possessed poor protective property. Numerous pits and microcracks existed on the film, which could be the active paths for the initiation of stress corrosion cracking. The surface film formed at -350 mV, mainly consisted of ferric oxides. It has high reaction resistance and offered good protection for the substrate.
文摘Schwannoma is a well-described,benign nerve sheath tumor of the soft tissue,but is rare in the gastrointestinal tract.Gastrointestinal schwannomas are often incidentally discovered as small polypoid intraluminal lesions.In this report,we describe the clinicopathologic and immunohistochemical features of a distinctive neural mucosal polyp composed of a diffuse cellular proliferation of uniform bland spindled cells in the lamina propria that entraps the colonic crypts.Immunohistochemical analysis revealed strong and diffuse positivity for the S-100 protein.To avoid confusion of these solitary colorectal polyps containing pure spindled Schwann cell proliferation in the lamina propria with neural lesions that have significant association with inherited syndromes,it is better to use the designation "mucosal Schwann hamartoma".
基金Supported by the National Natural Science Foundation of China under Grant No.11374133the Ph.D.Foundation of Tangshan Normal University under Grant No.2015A06+1 种基金the Science and Technology Project of Hebei Province under Grant No.16274522the Education Project of Hebei Province under Grant No.QN2015328
文摘Due to the effect of Coulomb potential, the angular distribution of electron ionized in an elliptically polarized field presents an asymmetric structure, which is called "Coulomb asymmetry". In this paper, we study how to modulate the asymmetric degree of the electron angular distribution by using a semi-classical simplified tunneling model. It is found that the asymmetric structure is easily affected by three parameters: the ionization potential, the laser ellipticity,and the laser wavelength. However, the laser intensity has little effect on the asymmetric structure. To explain these phenomena we have derived an analytical formula, which clearly demonstrates the relationship between the asymmetric degree and these parameters. Moreover, we find that in elliptically polarized laser field only those electrons that are released in a certain narrow window of initial field phase are greatly effected by the Coulomb potential and play the key role in the formation of asymmetric structure. This study provides some reference values in the development of attoclock technique, which can be used to probe the tunneling process.
