There are two approaches of defining the solutions of a set-valued optimization problem： vector criterion and set criterion. This note is devoted to higher-order optimality conditions using both criteria of solutions...There are two approaches of defining the solutions of a set-valued optimization problem： vector criterion and set criterion. This note is devoted to higher-order optimality conditions using both criteria of solutions for a constrained set-valued optimization problem in terms of higher-order radial derivatives. In the case of vector criterion, some optimality conditions are derived for isolated （weak） minimizers. With set criterion, necessary and sufficient optimality conditions are established for minimal solutions relative to lower set-order relation.展开更多
Bi_(2)Te_(3)films are grown on(111)-oriented GaAs substrates by using the hot wall epitaxy method and the surface oxidation properties in the films are investigated by x-ray photoelectron spectroscopy,Raman spectrosco...Bi_(2)Te_(3)films are grown on(111)-oriented GaAs substrates by using the hot wall epitaxy method and the surface oxidation properties in the films are investigated by x-ray photoelectron spectroscopy,Raman spectroscopy,and x-ray diffraction.The results show that the films are c-axis oriented.Two pairs of new peaks in the XPS spectra involved with the binding energies from Bi 4f and Te 3d electrons correspond to Bi–O–Te bonds.Besides the A^(1)_(1)g,E^(2)g and A^(2)_(1)g vibration modes from Bi_(2)Te_(3)films,two new peaks at 93.5 cm^(-1)and 123 cm^(-1)are observed in Raman spectra,which are assigned toα-Bi2O_(3)and TeO_(2),respectively.Our results are helpful for analyzing the degradation mechanism of topological surface states in Bi_(2)Te_(3).展开更多
Low-field magnetotransport properties of two-dimensional electron gases(2DEGs)are investigated in Al_(0.22)Ga_(0.78)N/GaN heterostructures.By means of a tilting magnetic field,unexpected oscillations of magnetoresisti...Low-field magnetotransport properties of two-dimensional electron gases(2DEGs)are investigated in Al_(0.22)Ga_(0.78)N/GaN heterostructures.By means of a tilting magnetic field,unexpected oscillations of magnetoresistivity are observed in a weak localization region.Qualitative understanding based on Altshuler–Aronov–Spivak oscillations is proposed for the case of interface disorder in Al_(0.22)Ga_(0.78)N/GaN heterostructures.展开更多
基金Supported by the National Natural Science Foundation of China(11361001)Natural Science Foundation of Ningxia(NZ14101)
文摘There are two approaches of defining the solutions of a set-valued optimization problem： vector criterion and set criterion. This note is devoted to higher-order optimality conditions using both criteria of solutions for a constrained set-valued optimization problem in terms of higher-order radial derivatives. In the case of vector criterion, some optimality conditions are derived for isolated （weak） minimizers. With set criterion, necessary and sufficient optimality conditions are established for minimal solutions relative to lower set-order relation.
基金Supported by the National Basic Research Program of China under Grant Nos 2012CB934300 and 2012CB619200the National Natural Science Foundation of China under Grant Nos 61290304,11074265 and 11174307the Natural Science Foundation of Shanghai(12ZR1435500).
文摘Bi_(2)Te_(3)films are grown on(111)-oriented GaAs substrates by using the hot wall epitaxy method and the surface oxidation properties in the films are investigated by x-ray photoelectron spectroscopy,Raman spectroscopy,and x-ray diffraction.The results show that the films are c-axis oriented.Two pairs of new peaks in the XPS spectra involved with the binding energies from Bi 4f and Te 3d electrons correspond to Bi–O–Te bonds.Besides the A^(1)_(1)g,E^(2)g and A^(2)_(1)g vibration modes from Bi_(2)Te_(3)films,two new peaks at 93.5 cm^(-1)and 123 cm^(-1)are observed in Raman spectra,which are assigned toα-Bi2O_(3)and TeO_(2),respectively.Our results are helpful for analyzing the degradation mechanism of topological surface states in Bi_(2)Te_(3).
基金by the National Natural Science Foundation of China under Grant Nos 60806042,10774001 and 60990313the Research Fund for the Doctoral Program of Higher Education in China(200800011021)the Wuhan National High Magnetic Field Center(WHMFCKF2011004).
文摘Low-field magnetotransport properties of two-dimensional electron gases(2DEGs)are investigated in Al_(0.22)Ga_(0.78)N/GaN heterostructures.By means of a tilting magnetic field,unexpected oscillations of magnetoresistivity are observed in a weak localization region.Qualitative understanding based on Altshuler–Aronov–Spivak oscillations is proposed for the case of interface disorder in Al_(0.22)Ga_(0.78)N/GaN heterostructures.
