作者机构：
[Li, ZY] Cent China Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.;Huazhong Univ Sci & Technol, Dept Solid State Elect, Wuhan 430074, Peoples R China.
通讯机构：
[Li, ZY] C;Cent China Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
会议名称：
44th International Field Emission Symposium
会议时间：
JUL 07-11, 1997
会议地点：
NATL RES INST MET, TSUKUBA, JAPAN
会议主办单位：
Cent China Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.^Huazhong Univ Sci & Technol, Dept Solid State Elect, Wuhan 430074, Peoples R China.
摘要：
The paper introduced an effective binding energy Lambda'(eff) and emphasized the role it plays in the field evaporation in the configuration of a scanning tunneling microscope (STM). With this Lambda'(eff) an important modification has been made to Tsong's CE model formula for STM [Tien T. Tsong, Phys. Rev. B 44 (1991) 13 703]. As a consequence, for tip-sample distance 5 < d < 13 Angstrom, the high evaporation fields from Tsong's original formula were found greatly reduced. When d = 7.23 Angstrom, the recalculated evaporation field for Au-1 is 0.6 V/Angstrom, which is in good agreement with Chang's experiment [Phys. Rev. Lett. 72 (1994) 574]. Further the evaporation field was found highly localized. For d = 7.52 Angstrom, the evaporation field of Au-1 on top of a Au(1 1 1) surface atom was found several times lower than that at a hollow site. In the calculation we have proposed a universal binding function. In addition selected experimental results on nanostructure formation by positive or negative voltage pulses with Au, Ni, Cu, Pt(Ir) and W tips on Au(1 1 1) substrate with a STM working in atmosphere were presented. The processes were found to bear important feature of field evaporation. (C) 1998 Published by Elsevier Science B.V. All rights reserved.
期刊：
Physica C: Superconductivity and its Applications,1997年282-287(PART3):1611-1612 ISSN：0921-4534
通讯作者：
Li, JQ
作者机构：
SE UNIV,ANAL & TEST CTR,NANJING 210018,PEOPLES R CHINA.;NANJING UNIV,DEPT PHYS,NANJING 210093,PEOPLES R CHINA.;NANJING UNIV,NATL LAB SOLID STATE MICROSTRUCT,NANJING 210093,PEOPLES R CHINA.;CENT CHINA NORMAL UNIV,DEPT PHYS,WUHAN,PEOPLES R CHINA.;[Li, JQ] CITY UNIV HONG KONG,DEPT PHYS & MAT SCI,HONG KONG,HONG KONG.
通讯机构：
[Li, JQ] C;CITY UNIV HONG KONG,DEPT PHYS & MAT SCI,HONG KONG,HONG KONG.
会议名称：
International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V
会议时间：
FEB 28-MAR 04, 1997
会议地点：
BEIJING, PEOPLES R CHINA
会议主办单位：
SE UNIV,ANAL & TEST CTR,NANJING 210018,PEOPLES R CHINA.^NANJING UNIV,DEPT PHYS,NANJING 210093,PEOPLES R CHINA.^NANJING UNIV,NATL LAB SOLID STATE MICROSTRUCT,NANJING 210093,PEOPLES R CHINA.^CENT CHINA NORMAL UNIV,DEPT PHYS,WUHAN,PEOPLES R CHINA.
摘要：
The effect of hydrogenation on the positron annihilation in different oxygenated YBa2Cu3O7-delta superconductors have been investigated. Experimental results showed that the effect of the hydrogenation process is to affect the concentrations of monovacancy and microvoid in both of intragrain and intergrain of the sample. The hydrogenation effect in the YBCO superconductor can be classified into four stages. In the first stage, i.e. for the initial hydrogen charging, the hydrogen atoms fill into the monovacancies and microvoids. The long lifetime tau(2) for positron annihilation is increased, and reaches the maximum value when monovacancies and microvoids have been fully filled with hydrogen atoms. In the second stage, the further hydrogen charging leads to the formation of new monovacancies. The long lifetime tau(2) decreases and reaches a minimum value at the end of this stage. In the third stage, the further hydrogen charging promotes the formation of microvoids by coalescence of clustered monovacancies and leads to increase tau(2) again. Finally in the fourth stage, zz reaches a steady state which corresponds to the equilibrium concentrations for both monovacancy and microvoid maintained at the temperature of the material.
作者机构：
[Guanghan L.; Dandan, S; Hong, J] Department of Chemistry, Central China Normal University, 430070, Wuhan, China
通讯机构：
[Lu, GH] C;CENT CHINA NORMAL UNIV,DEPT CHEM,WUHAN 430070,PEOPLES R CHINA.
会议名称：
Workshop on Mediterranean Aspects of Meat Quality as Related to Muscle Biochemistry
会议时间：
MAY 09-10, 1996
会议地点：
SEGOVIA, SPAIN
摘要：
A sensitive anodic stripping procedure for trace nitrite in the presence of added cetyltrimethylammonium bromide (CTMAB) is described. The method is based on the electrodeposition and subsequent oxidation of CTMAB-nitrite complex on a glassy carbon electrode in a supporting solution, consisting of Britten-Robinson buffer solution, pH range 3.6-4.0, and CTMAB. The peak height is proportional to the concentration of nitrite over the range 0.01-0.25 μg ml-1, and the relative standard deviation is less than 3.3%. This method has been used for the determination of trace nitrite in water and meat products with 90-110% recovery.
