光催化灭活是公认的控制病原微生物最具前景手段之一。本文以尿素和硫代巴比妥酸为起始原料,通过热聚合反应制备S掺杂g-C_(3)N_(4)(SCN),随后采用光还原法将Ag纳米粒负载于SCN表面获得新颖的可见光响应型Ag/SCN抗菌材料。对所制备纳米...光催化灭活是公认的控制病原微生物最具前景手段之一。本文以尿素和硫代巴比妥酸为起始原料,通过热聚合反应制备S掺杂g-C_(3)N_(4)(SCN),随后采用光还原法将Ag纳米粒负载于SCN表面获得新颖的可见光响应型Ag/SCN抗菌材料。对所制备纳米材料进行XRD、SEM、TEM、XPS及UV-Vis DRS表征,并深入探讨其在可见光下灭活大肠杆菌(E.coli)的性能和机制。结果表明,Ag纳米粒均匀且牢固地负载在SCN表面,纳米材料表现出显著增强的可见光响应能力。当负载量为6%时,Ag/SCN-6呈现出最佳的光催化灭菌活性,60 min内能够将6.2 lg CFU·mL^(-1)的E.coli全部灭活。自由基捕获实验结果表明,超氧自由基(·O-2)是灭活过程中最主要活性物种,它协同光生空穴(h+)和羟基自由基(·OH)主导了光催化抗菌的进程。展开更多
In order to improve the photocatalytic performance of mesoporous titania under visible light, a series of photocatalysts of S and Ag co-doped mesoporous titania have been successfully prepared by template method using...In order to improve the photocatalytic performance of mesoporous titania under visible light, a series of photocatalysts of S and Ag co-doped mesoporous titania have been successfully prepared by template method using thiourea, AgNO3 and tetrabutyl titanate as precursors and Pluronic P123 （EO20PO70EO20） as template. Scanning electron microscopy （SEM）, X-ray diffraction （XRD）, nitrogen adsorption-desorption measurements, and UV-visible spectroscopy （UV-Vis） were employed to characterize the morphology, crystal structure, surface structure, and optical absorption properties of the samples. The microcrystal of the photocatalysts consisted of anatase phase and was approximately present in the form of spherical particle. The photocatalytic performance was studied by photodegradation methyl orange （MO） in water under UV and visible light irradiation. The calcination temperature and the doping content influenced the photoactivity. In addition, the possibility of cyclic usage of co-doped mesoporous titania was also confirmed, the photocatalytic activity of mesoporous titania remained above 89% of that of the fresh sample after being used four times. It was shown that the co-doped mesoporous titania could be activated by visible light and could thus be potentially applied for the treatment of water contaminated by organic pollutants. The synergistic effect of sulfur and silver co-doping played an important role in improving the photocatalytic activity.展开更多
TiO2 doped with C, N and S (TCNS photocatalyst) was prepared by hydrolysis process using titanium iso-propoxide and thiourea. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron micro...TiO2 doped with C, N and S (TCNS photocatalyst) was prepared by hydrolysis process using titanium iso-propoxide and thiourea. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photo electron spectroscopy (XPS), BET surface area, FTIR and diffuse reflectance spectra (DRS). The results showed that the prepared catalysts are anatase type and nanosized par-ticles. The catalysts exhibited stronger absorption in the visible light region with a red shift in the adsorption edge. The photocatalytic activity of TCNS photocatalysts was evaluated by the photocatalytic degradation of isoproturon pesticide in aqueous solution. In the present study the maximum activity was achieved for TCNS5 catalyst at neutral pH with 1 g L-1 catalyst amount and at 1.14 x 10-4 M concentration of the pesticide solution. The TCNS photocatalysts showed higher phtocatalytic activity under solar light irradiation. This is attributed to the synergetic effects of red shift in the absorption edge, higher surface area and the inhibition of charge carrier recombination process.展开更多
Although silver(Ag) substitution offers several benefits in eliminating bulk defects and facilitating interface type inversion for Cu2ZnSn(S,Se)4(CZTSSe) photovoltaic(PV) technology, its further development is still h...Although silver(Ag) substitution offers several benefits in eliminating bulk defects and facilitating interface type inversion for Cu2ZnSn(S,Se)4(CZTSSe) photovoltaic(PV) technology, its further development is still hindered by the fairly low electrical conductivity due to the significant decrease of acceptors amount.In this work, a versatile Li–Ag co-doping strategy is demonstrated to mitigate the poor electrical conductivity arising from Ag through direct incorporating Li via postdeposition treatment(PDT) on top of the Ag-substituted CZTSSe absorber. Depth characterizations demonstrate that Li incorporation increases ptype carrier concentration, improves the carrier collection within the bulk, reduces the defects energy level as well as inverts the electric field polarity at grain boundaries(GBs) for Ag-substituted CZTSSe system. Benefiting from this lithium-assisted complex engineering of electrical performance both in grain interior(GI) and GBs, the power conversion efficiency(PCE) is finally increased from 9.21% to 10.29%. This systematic study represents an effective way to overcome the challenges encountered in Ag substitution,and these findings support a new aspect that the synergistic effects of double cation dopant will further pave the way for the development of high efficiency kesterite PV technology.展开更多
The Weiquan Ag-polymetallic deposit is located on the southern margin of the Central Asian Orogenic Belt and in the western segment of the Aqishan-Yamansu arc belt in East Tianshan,northwestern China. Its orebodies, c...The Weiquan Ag-polymetallic deposit is located on the southern margin of the Central Asian Orogenic Belt and in the western segment of the Aqishan-Yamansu arc belt in East Tianshan,northwestern China. Its orebodies, controlled by faults, occur in the lower Carboniferous volcanosedimentary rocks of the Yamansu Formation as irregular veins and lenses. Four stages of mineralization have been recognized on the basis of mineral assemblages, ore fabrics, and crosscutting relationships among the ore veins. Stage I is the skarn stage(garnet + pyroxene), Stage Ⅱ is the retrograde alteration stage(epidote + chlorite + magnetite ± hematite 士 actinolite ± quartz),Stage Ⅲ is the sulfide stage(Ag and Bi minerals + pyrite + chalcopyrite + galena + sphalerite + quartz ± calcite ± tetrahedrite),and Stage IV is the carbonate stage(quartz + calcite ± pyrite). Skarnization,silicification, carbonatization,epidotization,chloritization, sericitization, and actinolitization are the principal types of hydrothermal alteration. LAICP-MS U-Pb dating yielded ages of 326.5±4.5 and 298.5±1.5 Ma for zircons from the tuff and diorite porphyry, respectively. Given that the tuff is wall rock and that the orebodies are cut by a late diorite porphyry dike, the ages of the tuff and the diorite porphyry provide lower and upper time limits on the age of ore formation. The δ13C values of the calcite samples range from-2.5‰ to 2.3‰, the δ18OH2 Oand δDVSMOWvalues of the sulfide stage(Stage Ⅲ) vary from 1.1‰ to 5.2‰ and-111.7‰ to-66.1‰, respectively,and the δ13C, δ18OH2 Oand δDV-SMOWvalues of calcite in one Stage IV sample are 1.5‰,-0.3‰, and-115.6‰, respectively. Carbon, hydrogen, and oxygen isotopic compositions indicate that the ore-forming fluids evolved gradually from magmatic to meteoric sources. The δ34SV-CDTvalues of the sulfides have a large range from-6.9‰ to 1.4‰, with an average of-2.2‰, indicating a magmatic source, possibly with sedimentary contributions. The206Pb/204Pb,207Pb/204Pb, and208Pb/204Pb ratios of the sulfides are 17.9848-18.2785,15.5188-15.6536, and 37.8125-38.4650, respectively, and one whole-rock sample at Weiquan yields206Pb/204Pb,207Pb/204Pb, and208Pb/204Pb ratios of 18.2060, 15.5674, and 38.0511,respectively. Lead isotopic systems suggest that the ore-forming materials of the Weiquan deposit were derived from a mixed source involving mantle and crustal components. Based on geological features, zircon U-Pb dating, and C-H-OS-Pb isotopic data, it can be concluded that the Weiquan polymetallic deposit is a skarn type that formed in a tectonic setting spanning a period from subduction to post-collision. The ore materials were sourced from magmatic ore-forming fluids that mixed with components derived from host rocks during their ascent, and a gradual mixing with meteoric water took place in the later stages.展开更多
Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effec...Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effect of S is better than that of C or N on the tunable photocatalytic activities of BiOCl. At low concentration, S-doped BiOCl systems are the most stable under Bi-rich growth conditions because of their lower impurity-formation energy. Compared with the electronic structures of S-doped BiOCl, C-or N-doped BiOCl have relatively deeper impurity energy levels appearing in their band gap(except Bi_(36)O_(35)NCl_(36)), which may act as photogenerated carrier-recombination centers and reduce photocatalytic activity. At high concentration, S is substituted on the O lattice site system, whereas some S 3p states mix with the valence band; this mixture leads to an obvious band-gap decrease and continuum-state formation above the valence-band edge of BiOCl. Such activity is advantageous to photochemical catalysis response. Compared with pure Bi OCl and a low-concentration S-doped system, a high-concentration S-doped system shows an obvious redshift on the absorption edge and has better photocatalytic O_2 evolution performance.展开更多
The physical aging behavior of atactic polystyrene (aPS) films achieved under different drawing conditions has been studied by optical birefringence and modulate differential scanning: calorimeter (m.d.s.c.). The resu...The physical aging behavior of atactic polystyrene (aPS) films achieved under different drawing conditions has been studied by optical birefringence and modulate differential scanning: calorimeter (m.d.s.c.). The results show that on annealing at specific temperature below glass transition temperatue (T-g), the enthalpy relaxation (Delta H) and T-g decrease with increasing of birefringence (Delta n). On the other baud, the effect of molecular draw ratio (MDR) is confusing: Delta H and T-g decrease with increasing of MDR in the early stage of aging, but the MDR's effect become unobvious with the development of aging. It may be concluded that the ordered domain generated by the drawing below or above glass transition temperature will affect the development of physical aging behavior. The viewpoint of cohesional entanglement is used to account for the above observations.展开更多
GABA transporter 1(GAT1) takes important roles in multiple physiological processes through the uptake and release of GABA, but the regulation of GAT1 gene expression in different tissues is rarely known. To address th...GABA transporter 1(GAT1) takes important roles in multiple physiological processes through the uptake and release of GABA, but the regulation of GAT1 gene expression in different tissues is rarely known. To address the question, first, 5’ Rapid amplification of cDNA end (RACE) was used to determine GAT1 transcriptional starting sites in neonatal mouse cerebral cortex and intestine, adult mouse brain and adult rat testis. The products of 5’RACE were confirmed by DNA sequencing. We found that the transcript of GAT1 in neonatal mouse cerebral cortex and adult mouse brain starts at the same site (inside of exon 1), while in mouse intestine, GAT1 starts transcription in intron 1, and in rat testis, the transcript of GAT1 has an additional untranslation exon to the 5’ direction.展开更多
文摘光催化灭活是公认的控制病原微生物最具前景手段之一。本文以尿素和硫代巴比妥酸为起始原料,通过热聚合反应制备S掺杂g-C_(3)N_(4)(SCN),随后采用光还原法将Ag纳米粒负载于SCN表面获得新颖的可见光响应型Ag/SCN抗菌材料。对所制备纳米材料进行XRD、SEM、TEM、XPS及UV-Vis DRS表征,并深入探讨其在可见光下灭活大肠杆菌(E.coli)的性能和机制。结果表明,Ag纳米粒均匀且牢固地负载在SCN表面,纳米材料表现出显著增强的可见光响应能力。当负载量为6%时,Ag/SCN-6呈现出最佳的光催化灭菌活性,60 min内能够将6.2 lg CFU·mL^(-1)的E.coli全部灭活。自由基捕获实验结果表明,超氧自由基(·O-2)是灭活过程中最主要活性物种,它协同光生空穴(h+)和羟基自由基(·OH)主导了光催化抗菌的进程。
基金This work was supported by the National Natural Sci- ence Foundation of China （No.41373127） and the Liaoning Provincial Natural Science Foundation of China （No.2013020121）.
文摘In order to improve the photocatalytic performance of mesoporous titania under visible light, a series of photocatalysts of S and Ag co-doped mesoporous titania have been successfully prepared by template method using thiourea, AgNO3 and tetrabutyl titanate as precursors and Pluronic P123 （EO20PO70EO20） as template. Scanning electron microscopy （SEM）, X-ray diffraction （XRD）, nitrogen adsorption-desorption measurements, and UV-visible spectroscopy （UV-Vis） were employed to characterize the morphology, crystal structure, surface structure, and optical absorption properties of the samples. The microcrystal of the photocatalysts consisted of anatase phase and was approximately present in the form of spherical particle. The photocatalytic performance was studied by photodegradation methyl orange （MO） in water under UV and visible light irradiation. The calcination temperature and the doping content influenced the photoactivity. In addition, the possibility of cyclic usage of co-doped mesoporous titania was also confirmed, the photocatalytic activity of mesoporous titania remained above 89% of that of the fresh sample after being used four times. It was shown that the co-doped mesoporous titania could be activated by visible light and could thus be potentially applied for the treatment of water contaminated by organic pollutants. The synergistic effect of sulfur and silver co-doping played an important role in improving the photocatalytic activity.
文摘TiO2 doped with C, N and S (TCNS photocatalyst) was prepared by hydrolysis process using titanium iso-propoxide and thiourea. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photo electron spectroscopy (XPS), BET surface area, FTIR and diffuse reflectance spectra (DRS). The results showed that the prepared catalysts are anatase type and nanosized par-ticles. The catalysts exhibited stronger absorption in the visible light region with a red shift in the adsorption edge. The photocatalytic activity of TCNS photocatalysts was evaluated by the photocatalytic degradation of isoproturon pesticide in aqueous solution. In the present study the maximum activity was achieved for TCNS5 catalyst at neutral pH with 1 g L-1 catalyst amount and at 1.14 x 10-4 M concentration of the pesticide solution. The TCNS photocatalysts showed higher phtocatalytic activity under solar light irradiation. This is attributed to the synergetic effects of red shift in the absorption edge, higher surface area and the inhibition of charge carrier recombination process.
基金the National Natural Science Foundation of China(61874159,61974173,51702085,51802081 and 21603058)the Joint Talent Cultivation Funds of NSFC-HN(U1704151)the Science and Technology Innovation Talents in Universities of Henan Province(18HASTIT016)。
文摘Although silver(Ag) substitution offers several benefits in eliminating bulk defects and facilitating interface type inversion for Cu2ZnSn(S,Se)4(CZTSSe) photovoltaic(PV) technology, its further development is still hindered by the fairly low electrical conductivity due to the significant decrease of acceptors amount.In this work, a versatile Li–Ag co-doping strategy is demonstrated to mitigate the poor electrical conductivity arising from Ag through direct incorporating Li via postdeposition treatment(PDT) on top of the Ag-substituted CZTSSe absorber. Depth characterizations demonstrate that Li incorporation increases ptype carrier concentration, improves the carrier collection within the bulk, reduces the defects energy level as well as inverts the electric field polarity at grain boundaries(GBs) for Ag-substituted CZTSSe system. Benefiting from this lithium-assisted complex engineering of electrical performance both in grain interior(GI) and GBs, the power conversion efficiency(PCE) is finally increased from 9.21% to 10.29%. This systematic study represents an effective way to overcome the challenges encountered in Ag substitution,and these findings support a new aspect that the synergistic effects of double cation dopant will further pave the way for the development of high efficiency kesterite PV technology.
基金funded by the China Geological Survey (No. 1212011220731)
文摘The Weiquan Ag-polymetallic deposit is located on the southern margin of the Central Asian Orogenic Belt and in the western segment of the Aqishan-Yamansu arc belt in East Tianshan,northwestern China. Its orebodies, controlled by faults, occur in the lower Carboniferous volcanosedimentary rocks of the Yamansu Formation as irregular veins and lenses. Four stages of mineralization have been recognized on the basis of mineral assemblages, ore fabrics, and crosscutting relationships among the ore veins. Stage I is the skarn stage(garnet + pyroxene), Stage Ⅱ is the retrograde alteration stage(epidote + chlorite + magnetite ± hematite 士 actinolite ± quartz),Stage Ⅲ is the sulfide stage(Ag and Bi minerals + pyrite + chalcopyrite + galena + sphalerite + quartz ± calcite ± tetrahedrite),and Stage IV is the carbonate stage(quartz + calcite ± pyrite). Skarnization,silicification, carbonatization,epidotization,chloritization, sericitization, and actinolitization are the principal types of hydrothermal alteration. LAICP-MS U-Pb dating yielded ages of 326.5±4.5 and 298.5±1.5 Ma for zircons from the tuff and diorite porphyry, respectively. Given that the tuff is wall rock and that the orebodies are cut by a late diorite porphyry dike, the ages of the tuff and the diorite porphyry provide lower and upper time limits on the age of ore formation. The δ13C values of the calcite samples range from-2.5‰ to 2.3‰, the δ18OH2 Oand δDVSMOWvalues of the sulfide stage(Stage Ⅲ) vary from 1.1‰ to 5.2‰ and-111.7‰ to-66.1‰, respectively,and the δ13C, δ18OH2 Oand δDV-SMOWvalues of calcite in one Stage IV sample are 1.5‰,-0.3‰, and-115.6‰, respectively. Carbon, hydrogen, and oxygen isotopic compositions indicate that the ore-forming fluids evolved gradually from magmatic to meteoric sources. The δ34SV-CDTvalues of the sulfides have a large range from-6.9‰ to 1.4‰, with an average of-2.2‰, indicating a magmatic source, possibly with sedimentary contributions. The206Pb/204Pb,207Pb/204Pb, and208Pb/204Pb ratios of the sulfides are 17.9848-18.2785,15.5188-15.6536, and 37.8125-38.4650, respectively, and one whole-rock sample at Weiquan yields206Pb/204Pb,207Pb/204Pb, and208Pb/204Pb ratios of 18.2060, 15.5674, and 38.0511,respectively. Lead isotopic systems suggest that the ore-forming materials of the Weiquan deposit were derived from a mixed source involving mantle and crustal components. Based on geological features, zircon U-Pb dating, and C-H-OS-Pb isotopic data, it can be concluded that the Weiquan polymetallic deposit is a skarn type that formed in a tectonic setting spanning a period from subduction to post-collision. The ore materials were sourced from magmatic ore-forming fluids that mixed with components derived from host rocks during their ascent, and a gradual mixing with meteoric water took place in the later stages.
基金This project was supported by the China Postdoctoral Science Foundation,Henan Postdoctoral Science Foundation,NCWU 2017 Annual Teaching Teacher Training Object ProjectKey Research Projects of Higher Education in Henan Province(18B150010)+1 种基金the Key Scientific Research Project of Henan Higher Education(No.17A520011)the Science and Technology Research Project of Henan Province(182102110029)
文摘Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effect of S is better than that of C or N on the tunable photocatalytic activities of BiOCl. At low concentration, S-doped BiOCl systems are the most stable under Bi-rich growth conditions because of their lower impurity-formation energy. Compared with the electronic structures of S-doped BiOCl, C-or N-doped BiOCl have relatively deeper impurity energy levels appearing in their band gap(except Bi_(36)O_(35)NCl_(36)), which may act as photogenerated carrier-recombination centers and reduce photocatalytic activity. At high concentration, S is substituted on the O lattice site system, whereas some S 3p states mix with the valence band; this mixture leads to an obvious band-gap decrease and continuum-state formation above the valence-band edge of BiOCl. Such activity is advantageous to photochemical catalysis response. Compared with pure Bi OCl and a low-concentration S-doped system, a high-concentration S-doped system shows an obvious redshift on the absorption edge and has better photocatalytic O_2 evolution performance.
基金This work was Supported by the National Basic Research Project-Macromolecular Condensed State
文摘The physical aging behavior of atactic polystyrene (aPS) films achieved under different drawing conditions has been studied by optical birefringence and modulate differential scanning: calorimeter (m.d.s.c.). The results show that on annealing at specific temperature below glass transition temperatue (T-g), the enthalpy relaxation (Delta H) and T-g decrease with increasing of birefringence (Delta n). On the other baud, the effect of molecular draw ratio (MDR) is confusing: Delta H and T-g decrease with increasing of MDR in the early stage of aging, but the MDR's effect become unobvious with the development of aging. It may be concluded that the ordered domain generated by the drawing below or above glass transition temperature will affect the development of physical aging behavior. The viewpoint of cohesional entanglement is used to account for the above observations.
基金foundations from Chinese Academy of Sciences and Special Funds for Major State Basic reseaxch of China (G1999053903).
文摘GABA transporter 1(GAT1) takes important roles in multiple physiological processes through the uptake and release of GABA, but the regulation of GAT1 gene expression in different tissues is rarely known. To address the question, first, 5’ Rapid amplification of cDNA end (RACE) was used to determine GAT1 transcriptional starting sites in neonatal mouse cerebral cortex and intestine, adult mouse brain and adult rat testis. The products of 5’RACE were confirmed by DNA sequencing. We found that the transcript of GAT1 in neonatal mouse cerebral cortex and adult mouse brain starts at the same site (inside of exon 1), while in mouse intestine, GAT1 starts transcription in intron 1, and in rat testis, the transcript of GAT1 has an additional untranslation exon to the 5’ direction.
