A novel design of IR OTTLE is shown to have sufficient sensitivity and experi- mental simplicity for obtaining IR spectra of the species generated during electrochemical oxidation-reduction.
BVRI CCD photometry of the poorly studied open cluster NGC 6724 has been carried out down to a limiting magnitude of V-20 mag. The stars of the cluster have been observed using the Newtonian focus （f/4.84） of the 74...BVRI CCD photometry of the poorly studied open cluster NGC 6724 has been carried out down to a limiting magnitude of V-20 mag. The stars of the cluster have been observed using the Newtonian focus （f/4.84） of the 74-inch telescope at Kottamia Astronomical Observatory in Egypt. Also, the 2MASS - JHK system is used to confirm the results we obtained. The main photometric parameters have been estimated for the present object; the diameter is found to be 6 arcmin, the distance is 15304-60pc from the Sun and the age is 900＋50Myr. The optical reddening E（B - V） = 0.65 mag, while the infrared reddening is E（J - H） = 0.20 mag. The slope of the mass function distribution and the relaxation time estimations indicate that cluster NGC 6724 is dynamically relaxed.展开更多
Non-centrosymmetric chalcogenides are attracting considerable attention as highly promising infrared nonlinear optical (IR-NLO) candidates,but it is challenging to simultaneously achieve sufficient secondharmonic-gene...Non-centrosymmetric chalcogenides are attracting considerable attention as highly promising infrared nonlinear optical (IR-NLO) candidates,but it is challenging to simultaneously achieve sufficient secondharmonic-generation coefficient (d_(eff)>0.5×AgGaS_(2)) and large energy gap (E_g>3.5 e V).In this work,a novel ternary chalcogenide,Cs_(5)Ga_(9)S_(16) with an ultra-wide E_gof 4.05 e V,has been successfully obtained.This sulfide belongs to the monoclinic space group Pn (No.7) with a novel 3D anionic[Ga_(9)S_(16)]^(5–)framework that is formed by super-polyhedral[Ga_(9)S_(23)]units through corner-sharing S atoms.Such a unique crystal structure displays desirable characteristics which indicate a promising IR-NLO candidate:favourable phase-matching feature,sufficient d_(eff)(0.7×AgGaS_(2)),ultrahigh laser-induced damage threshold (31.6×AgGaS_(2)) and broad transparent region (0.27-14.96μm).In addition,systematic theoretical studies and structural analysis suggest that the desirable IR-NLO performances can be attributed to the super-polyhedral building blocks.This finding may provide useful insight into the understanding and designing other high-performance IR-NLO candidates with super-polyhedral-built structures.展开更多
GaSb is the most suitable substrate in the epitaxial growth of mixed semiconductors of GaSb system.In this work,Te-doped GaSb bulk crystals with different doping concentration have been annealed at 550℃ for100 h in a...GaSb is the most suitable substrate in the epitaxial growth of mixed semiconductors of GaSb system.In this work,Te-doped GaSb bulk crystals with different doping concentration have been annealed at 550℃ for100 h in ambient antimony.The annealed samples have been studied by Hall effect measurement,infrared（IR）optical transmission,Glow discharge mass spectroscopy（GDMS） and photoluminescence（PL） spectroscopy.After annealing,Te-doped GaSb samples exhibit a decrease of carrier concentration and increase of mobility,along with an improvement of below gap IR transmission.Native acceptor related electrical compensation analysis suggests a formation of donor defect with deeper energy level.The mechanism of the variation of the defect and its influence on the material properties are discussed.展开更多
文摘A novel design of IR OTTLE is shown to have sufficient sensitivity and experi- mental simplicity for obtaining IR spectra of the species generated during electrochemical oxidation-reduction.
文摘BVRI CCD photometry of the poorly studied open cluster NGC 6724 has been carried out down to a limiting magnitude of V-20 mag. The stars of the cluster have been observed using the Newtonian focus （f/4.84） of the 74-inch telescope at Kottamia Astronomical Observatory in Egypt. Also, the 2MASS - JHK system is used to confirm the results we obtained. The main photometric parameters have been estimated for the present object; the diameter is found to be 6 arcmin, the distance is 15304-60pc from the Sun and the age is 900＋50Myr. The optical reddening E（B - V） = 0.65 mag, while the infrared reddening is E（J - H） = 0.20 mag. The slope of the mass function distribution and the relaxation time estimations indicate that cluster NGC 6724 is dynamically relaxed.
基金supported by the National Natural Science Foundation of China (Nos. 22175175, 21771179 and 21901246)Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China (No. 2021ZR118)+1 种基金the Natural Science Foundation of Fujian Province (No. 2019J01133)the Youth Innovation Promotion Association CAS (No. 2022303)。
文摘Non-centrosymmetric chalcogenides are attracting considerable attention as highly promising infrared nonlinear optical (IR-NLO) candidates,but it is challenging to simultaneously achieve sufficient secondharmonic-generation coefficient (d_(eff)>0.5×AgGaS_(2)) and large energy gap (E_g>3.5 e V).In this work,a novel ternary chalcogenide,Cs_(5)Ga_(9)S_(16) with an ultra-wide E_gof 4.05 e V,has been successfully obtained.This sulfide belongs to the monoclinic space group Pn (No.7) with a novel 3D anionic[Ga_(9)S_(16)]^(5–)framework that is formed by super-polyhedral[Ga_(9)S_(23)]units through corner-sharing S atoms.Such a unique crystal structure displays desirable characteristics which indicate a promising IR-NLO candidate:favourable phase-matching feature,sufficient d_(eff)(0.7×AgGaS_(2)),ultrahigh laser-induced damage threshold (31.6×AgGaS_(2)) and broad transparent region (0.27-14.96μm).In addition,systematic theoretical studies and structural analysis suggest that the desirable IR-NLO performances can be attributed to the super-polyhedral building blocks.This finding may provide useful insight into the understanding and designing other high-performance IR-NLO candidates with super-polyhedral-built structures.
基金Project supported by the National Natural Science Foundation of China(Nos.61474104,61504131)
文摘GaSb is the most suitable substrate in the epitaxial growth of mixed semiconductors of GaSb system.In this work,Te-doped GaSb bulk crystals with different doping concentration have been annealed at 550℃ for100 h in ambient antimony.The annealed samples have been studied by Hall effect measurement,infrared（IR）optical transmission,Glow discharge mass spectroscopy（GDMS） and photoluminescence（PL） spectroscopy.After annealing,Te-doped GaSb samples exhibit a decrease of carrier concentration and increase of mobility,along with an improvement of below gap IR transmission.Native acceptor related electrical compensation analysis suggests a formation of donor defect with deeper energy level.The mechanism of the variation of the defect and its influence on the material properties are discussed.
