The electronic properties of twinned ZnS nanowires （NWs） with different diameters were investigated based on first-principles calculations. The energy band structures, projected density of states and the spatial dis...The electronic properties of twinned ZnS nanowires （NWs） with different diameters were investigated based on first-principles calculations. The energy band structures, projected density of states and the spatial distributions of the bottom of conduction band and the top of the valence band were presented. The results show that the twinned nanowires exhibit a semiconducting character and the band gap decreases with increasing nanowire diameter due to quantum confinement effects. The valence band maximum and conduction band minimum originate mainly from the S-p and Zn-s orbitals at the core of the nanowires, respectively, which was confirmed by their spatial charge density distribution. We also found that no heterostructure is formed in the twinned ZnS NWs since the valence band maximum and conduction band minimum states are distributed along the NW axis uniformly. We suggest that the hexagonal （2H） stacking inside the cubic （3C） stacking has no effect on the electronic properties of thin ZnS NWs.展开更多
This research manuscript reports the heavy metal accumulation in four marine seaweeds sp. 1)?Caulerpa sertlatioides (Cuba);2) Caulerpa cf. brachypus;(Bali, Indonesia);3) Undaria pinnatifida (West-Donegal, Ireland);4) ...This research manuscript reports the heavy metal accumulation in four marine seaweeds sp. 1)?Caulerpa sertlatioides (Cuba);2) Caulerpa cf. brachypus;(Bali, Indonesia);3) Undaria pinnatifida (West-Donegal, Ireland);4) Ulva lactuca (Easters-Scheldt, the Netherlands). Mechanical pressure at 10 bar of fresh seaweed fronds casu quo biomass in the laboratory delivered seaweed moisture which was analyzed by Inductively Coupled Plasma Spectroscopy (ICP)-techniques for heavy-metals = [HM], (Al, As, Cd, Co, Cr, Cu, Fe, Mo, Ni, Pb & Zn). Three important observations were made: 1) The [HM] in the seaweed moisture is higher than in the surrounding seawater which directs to mechanism(s) of bio-accumulation;2) The accumulation factor [AF] is varying per metallic-cation with an overall trend for our four seaweeds and sampling locations for [HM] are: As & Co & Cu: 5000 - 10,000 μg/l;Ni & Zn: 3000 - 5000 μg/l;Cd: 2000 - 3000 μg/l;Cr: 1000 - 2000 μg/l;Al: 200 - 1000 μg/l;Mo & Pb & Fe: 0 - 200 μg/l range. 3) Seaweed moisture detected that [HM]: Pb & Zn & Fe—which all three could not be detected in the seawater—supports the view that seaweeds have a preference in their bio-accumulation mechanism for these three HM. Major conclusion is in general that “overall” for the macro-elements Ca, Fe, K, Mg, Mn, Na, P & S in the moisture of the four seaweed species the concentration is lower in the seaweed species, or equals the concentration, in comparison to the surrounding sea water. For the HM (Al, As, Cd, Co, Cr, Cu, Mo, Ni, Pb & Zn) the opposite is the case species and is the concentration “overall” higher in the seaweed species in comparison to the surrounding sea water. Further topics addressed include strategies of irrigation of the Sahara desert with the moisture out of seaweeds under conditions of low anthropogenic influences.展开更多
A Schiff base ligand 4-[indol-3-yl]-but-3-en-2-one benzoyl hydrazone (HL), and its four transition metal complexes (ML2,M=Cu(, Ni(, Zn( and Co() have been prepared and characterized by means of elemental analysis, EI-...A Schiff base ligand 4-[indol-3-yl]-but-3-en-2-one benzoyl hydrazone (HL), and its four transition metal complexes (ML2,M=Cu(, Ni(, Zn( and Co() have been prepared and characterized by means of elemental analysis, EI-MS, molar conductivity, IR, UV-Vis and 1H NMR. The results showed that HL as a bidentate ligand coordinated with transition metal ions to form four-coordination complexes. The antibacterial activity was studied by using the filter scraps diffusion method, and the results indicated that the ligand and the complexes had a low bacteriostatic activity against S. Aureu, P. Aeruginosa and E. Coli. The low in vitro antitumor activity of the title complexes was also observed by using MTT method against KB, A2780, Bel7402 and HELF.展开更多
new coordination polymer {[Zn(CF3COO)2(C5H5ON)]·H2O}n was synthesized based on the reaction of zinc(Ⅱ) trifluoroacetate and 3-hydroxypyridine(C5H5ON) in methanol medium for the first time. The structure of the c...new coordination polymer {[Zn(CF3COO)2(C5H5ON)]·H2O}n was synthesized based on the reaction of zinc(Ⅱ) trifluoroacetate and 3-hydroxypyridine(C5H5ON) in methanol medium for the first time. The structure of the coordination polymer was confirmed by IR, 1H NMR, elemental analysis and thermal analysis. The crystal structure of the coordination polymer was also determined by X-ray single crystal diffraction. The crystal belongs to monoclinic system with space group P21/m, and crystallographic data of the coordination polymer are: a= 0.863 1(4) nm, b=0.717 7(3) nm, c=1.116 4(5) nm, α=γ=90°, β=107.542(6)°, V=0.659 4(5) nm3; Dc=2.037 g·cm-3; Z=2; F(000)=400; μ=1.969 mm-1. Zinc(Ⅱ) atom lies at the center of an octahedron formed by the coordination of zinc atom and six O atoms which come from four different trifluoroacetate ions and two different 3-hydroxypyridine molecules where each trifluoroacetate ion and 3-hydroxypyridine are coordinated to two different zinc ions to form coordination polymer. CCDC: 253909.展开更多
Fiber-supercapacitors(FSCs)are promising power sources for miniature portable and wearable electronic devices.However,the development and practical application of these FSCs have been severely hindered by their low vo...Fiber-supercapacitors(FSCs)are promising power sources for miniature portable and wearable electronic devices.However,the development and practical application of these FSCs have been severely hindered by their low volumetric capacitance and narrow operating voltage.In this work,vertically aligned nickel cobalt sulfide(Ni Co2S4)nanowires grown on carbon nanotube(CNT)fibers were achieved through an in-situ two-step hydrothermal reaction method.The as-prepared Ni Co2S4@CNT fiber electrode exhibits a high volumetric capacitance of 2332 F cm-3,benefiting from its superior electric conductivity,large surface area,and rich Faradic redox reaction sites.Furthermore,a Ni Co2S4@CNT//VN@CNT(vanadium nitride nanosheets grown on CNT fibers)asymmetric fiber-supercapacitor(AFSC)was successfully fabricated.The device exhibits an operating voltage up to 1.6 V and a high volumetric energy density of 30.64m Wh cm-3.The device also possesses outstanding flexibility as evidenced by no obvious performance degradation under various bending angles and maintaining high capacitance after 5000 bending cycles.This work promotes the practical application of flexible wearable energy-storage devices.展开更多
基金Project supported by the Special Funds of the National Natural Science Foundation of China (Grant No. 10947102)the Foundation of the Education Committee of Chongqing (Grant No. KJ090503)
文摘The electronic properties of twinned ZnS nanowires （NWs） with different diameters were investigated based on first-principles calculations. The energy band structures, projected density of states and the spatial distributions of the bottom of conduction band and the top of the valence band were presented. The results show that the twinned nanowires exhibit a semiconducting character and the band gap decreases with increasing nanowire diameter due to quantum confinement effects. The valence band maximum and conduction band minimum originate mainly from the S-p and Zn-s orbitals at the core of the nanowires, respectively, which was confirmed by their spatial charge density distribution. We also found that no heterostructure is formed in the twinned ZnS NWs since the valence band maximum and conduction band minimum states are distributed along the NW axis uniformly. We suggest that the hexagonal （2H） stacking inside the cubic （3C） stacking has no effect on the electronic properties of thin ZnS NWs.
文摘This research manuscript reports the heavy metal accumulation in four marine seaweeds sp. 1)?Caulerpa sertlatioides (Cuba);2) Caulerpa cf. brachypus;(Bali, Indonesia);3) Undaria pinnatifida (West-Donegal, Ireland);4) Ulva lactuca (Easters-Scheldt, the Netherlands). Mechanical pressure at 10 bar of fresh seaweed fronds casu quo biomass in the laboratory delivered seaweed moisture which was analyzed by Inductively Coupled Plasma Spectroscopy (ICP)-techniques for heavy-metals = [HM], (Al, As, Cd, Co, Cr, Cu, Fe, Mo, Ni, Pb & Zn). Three important observations were made: 1) The [HM] in the seaweed moisture is higher than in the surrounding seawater which directs to mechanism(s) of bio-accumulation;2) The accumulation factor [AF] is varying per metallic-cation with an overall trend for our four seaweeds and sampling locations for [HM] are: As & Co & Cu: 5000 - 10,000 μg/l;Ni & Zn: 3000 - 5000 μg/l;Cd: 2000 - 3000 μg/l;Cr: 1000 - 2000 μg/l;Al: 200 - 1000 μg/l;Mo & Pb & Fe: 0 - 200 μg/l range. 3) Seaweed moisture detected that [HM]: Pb & Zn & Fe—which all three could not be detected in the seawater—supports the view that seaweeds have a preference in their bio-accumulation mechanism for these three HM. Major conclusion is in general that “overall” for the macro-elements Ca, Fe, K, Mg, Mn, Na, P & S in the moisture of the four seaweed species the concentration is lower in the seaweed species, or equals the concentration, in comparison to the surrounding sea water. For the HM (Al, As, Cd, Co, Cr, Cu, Mo, Ni, Pb & Zn) the opposite is the case species and is the concentration “overall” higher in the seaweed species in comparison to the surrounding sea water. Further topics addressed include strategies of irrigation of the Sahara desert with the moisture out of seaweeds under conditions of low anthropogenic influences.
文摘A Schiff base ligand 4-[indol-3-yl]-but-3-en-2-one benzoyl hydrazone (HL), and its four transition metal complexes (ML2,M=Cu(, Ni(, Zn( and Co() have been prepared and characterized by means of elemental analysis, EI-MS, molar conductivity, IR, UV-Vis and 1H NMR. The results showed that HL as a bidentate ligand coordinated with transition metal ions to form four-coordination complexes. The antibacterial activity was studied by using the filter scraps diffusion method, and the results indicated that the ligand and the complexes had a low bacteriostatic activity against S. Aureu, P. Aeruginosa and E. Coli. The low in vitro antitumor activity of the title complexes was also observed by using MTT method against KB, A2780, Bel7402 and HELF.
文摘new coordination polymer {[Zn(CF3COO)2(C5H5ON)]·H2O}n was synthesized based on the reaction of zinc(Ⅱ) trifluoroacetate and 3-hydroxypyridine(C5H5ON) in methanol medium for the first time. The structure of the coordination polymer was confirmed by IR, 1H NMR, elemental analysis and thermal analysis. The crystal structure of the coordination polymer was also determined by X-ray single crystal diffraction. The crystal belongs to monoclinic system with space group P21/m, and crystallographic data of the coordination polymer are: a= 0.863 1(4) nm, b=0.717 7(3) nm, c=1.116 4(5) nm, α=γ=90°, β=107.542(6)°, V=0.659 4(5) nm3; Dc=2.037 g·cm-3; Z=2; F(000)=400; μ=1.969 mm-1. Zinc(Ⅱ) atom lies at the center of an octahedron formed by the coordination of zinc atom and six O atoms which come from four different trifluoroacetate ions and two different 3-hydroxypyridine molecules where each trifluoroacetate ion and 3-hydroxypyridine are coordinated to two different zinc ions to form coordination polymer. CCDC: 253909.
基金funding support from the CASQueensland Collaborative Science Fund(121E32KYSB20160032)the National Natural Science Foundation of China(No.21403287,No.21433013,51402345,21773291)+1 种基金the National Key R&D Program of China(2016YFB0100100)the CAS-DOE Joint Research Program(121E32KYSB20150004)。
文摘Fiber-supercapacitors(FSCs)are promising power sources for miniature portable and wearable electronic devices.However,the development and practical application of these FSCs have been severely hindered by their low volumetric capacitance and narrow operating voltage.In this work,vertically aligned nickel cobalt sulfide(Ni Co2S4)nanowires grown on carbon nanotube(CNT)fibers were achieved through an in-situ two-step hydrothermal reaction method.The as-prepared Ni Co2S4@CNT fiber electrode exhibits a high volumetric capacitance of 2332 F cm-3,benefiting from its superior electric conductivity,large surface area,and rich Faradic redox reaction sites.Furthermore,a Ni Co2S4@CNT//VN@CNT(vanadium nitride nanosheets grown on CNT fibers)asymmetric fiber-supercapacitor(AFSC)was successfully fabricated.The device exhibits an operating voltage up to 1.6 V and a high volumetric energy density of 30.64m Wh cm-3.The device also possesses outstanding flexibility as evidenced by no obvious performance degradation under various bending angles and maintaining high capacitance after 5000 bending cycles.This work promotes the practical application of flexible wearable energy-storage devices.
