A new kind of apatite-type red-emitting Ba_(2)La_(8)(GeO_(4))_(6)O_(2):Eu^(3+)phosphor was prepared by high temperature solid-state method.The Rietveld analysis based on the powder diffraction data shows that Ba_(2)La...A new kind of apatite-type red-emitting Ba_(2)La_(8)(GeO_(4))_(6)O_(2):Eu^(3+)phosphor was prepared by high temperature solid-state method.The Rietveld analysis based on the powder diffraction data shows that Ba_(2)La_(8)(GeO_(4))_(6)O_(2):Eu^(3+)phosphors possess a pure apatite phase without any impurity.The emission spectrum of Ba_(2)La_(8)(GeO_(4))_(6)O_(2):Eu^(3+)phosphor consists of two bands,an orange emission band from 500 to 600 nm and a red emission band from 600 to 680 nm.By varying the amount of the doped europium ions from 0.02 to 0.14 mol,it is found that the luminescent properties of this rare earth phosphor are the best when the concentration of europium ion is 0.08 mol.The optimum concentration is eventually proved to be 0.08 mol.The Eu^(3+)doping dependent luminescence quenching can be further ascribed to dipole-quadrupole interactions.The quantum yield of Ba_(2)La_(7.92)(GeO_(4))_(6)O_(2):0.08 Eu^(3+)is 37.23%.The CIE analysis confirms a reddish emission in the near ultraviolet(n-UV)excitation.All these above properties of the phosphor can help in contribution of promoting white light-emitting diode.展开更多
To evaluate the impact of zinc sulfate(ZnSO_(4)) concentration on the structural properties of the films,Cd_(1-x)Zn_(x)S thin films were formed on glass substrates using chemical bath deposition(CBD) in this study.The...To evaluate the impact of zinc sulfate(ZnSO_(4)) concentration on the structural properties of the films,Cd_(1-x)Zn_(x)S thin films were formed on glass substrates using chemical bath deposition(CBD) in this study.The effect of ZnSO_(4) precursor concentration on the surface morphology,optical properties,and morphological structure of the Cd_(1-x)Zn_(x)S films was investigated.To study the impact of zinc doping content on the performance metrics of Cu(In_(1-x)Ga_(x))Se_(2)(CIGS)cells in the experimental group and to improve the buffer layer thickness,simulations were run using one-dimensional solar cell capacitance simulator(SCAPS-1D) software.展开更多
Background The genome of the severe acute respiratory syndrome-associated coronavirus ( SARS-CoV) includes sequences encoding the putative protein X4 ( ORF8, ORF7a), consisting of 122 amino acids. The deduced sequence...Background The genome of the severe acute respiratory syndrome-associated coronavirus ( SARS-CoV) includes sequences encoding the putative protein X4 ( ORF8, ORF7a), consisting of 122 amino acids. The deduced sequence contains a probable cleaved signal peptide sequence and a C-terminal transmembrane helix, indicating that protein X4 is likely to be a type I membrane protein. This study was conducted to demonstrate whether the protein X4 was expressed and its essential function in the process of SARS-CoV infection. Methods The prokaryotic and eukaryotic protein X4-expressing plasmids were constructed. Recombinant soluble protein X4 was purified from E. coli using ion exchange chromatography, and the preparation was injected into chicken for rising specific polyclonal antibodies. The expression of protein X4 in SARS-CoV infected Vero E6 cells and lung tissues from patients with SARS was performed using immunofluorescence assay and immunohistochemistry technique. The preliminary function of protein X4 was evaluated by treatment with and over-expression of protein X4 in cell lines. Western blot was employed to evaluate the expression of protein X4 in SARS-CoV particles. Results We expressed and purified soluble recombinant protein X4 from E. coli, and generated specific antibodies against protein X4. Western blot proved that the protein X4 was not assembled in the SARS-CoV particles. Indirect immunofluorescence assays revealed that the expression of protein X4 was detected at 8 hours after infection in SARS-CoV-infected Vero E6 cells. It was also detected in the tung tissues from patients with SARS. Treatment with and overexpression of protein X4 inhibited the growth of Balb/c 313 cells as determined by cell counting and MTT assays. Conclusion The results provide the evidence of protein X4 expression following SARS-CoV infection, and may facilitate further investigation of the immunopathological mechanism of SARS.展开更多
As a new type of light-collecting and luminescent material,all-inorganic cesium lead halide CsPbX_(3)(X=Cl,Br,I)perovskite nanocrystals(NCs)are expected to have a wide range of applications in the fields of photovolta...As a new type of light-collecting and luminescent material,all-inorganic cesium lead halide CsPbX_(3)(X=Cl,Br,I)perovskite nanocrystals(NCs)are expected to have a wide range of applications in the fields of photovoltaics,optoelectronics,and fluorescence anti-counterfeiting,etc.Therefore,improving the fluorescence performance and stability of CsPbX_(3)perovskite NCs to prompt their applications would promise both fundamental and practical significance for in-depth research in the field of halide perovskites.In this paper,we developed a modification strategy to introduce a halogen source,zinc bromide(ZnBr_(2))in hexane,to CsPbX_(3)perovskite that can be conducted under atmospheric conditions with reduced reaction cost and easier operation.The first work in this paper was to apply the modification strategy to CsPbI_(3)nanowires(NWs).Compared with the untreated NWs,the ZnBr_(2)/hexane modified CsPbI_(3)NWs exhibited better fluorescence properties.Subsequently,based on the study of perovskite NWs,we investigated perovskite nanocrystal-CsPbI_(3)nanorods(NRs)with different morphologies and sizes.It was found that the luminescence properties of nanorods(NRs)were superior.Later,we infiltrated the modified NRs into the aramid/polyphenylene sulfide(ACFs/PPS)composite paper yielded from our previous work to study its fluorescence performance for anti-counterfeiting.Their luminescence properties under ultraviolet light irradiation enable better performance in fluorescence anti-counterfeiting.The ZnBr_(2)/hexane modification strategy and the applications studied in this work will expand the scope of perovskite research,laying the foundation for the applications of fluorescent anti-counterfeiting,nano-photoelectric devices,and fluorescent composite materials.展开更多
In this paper,an aramid chopped fiber,so-called(ACF)/polyphenylene sulfide(PPS)composite,containing multi-walled carbon nanotubes(MWCNT),and in situ polymerized polypyrrole(PPy)was designed and fabricated,to be applie...In this paper,an aramid chopped fiber,so-called(ACF)/polyphenylene sulfide(PPS)composite,containing multi-walled carbon nanotubes(MWCNT),and in situ polymerized polypyrrole(PPy)was designed and fabricated,to be applied as a paper based electrode.The ACF/PPS/MWCNT-PPy electrode features highly porous paper-like structure with excel-lent electrochemical activity,rendering it a high areal capacitance of~3205 mF cm^(-2) at a current density of 5 mA cm^(-2).After 5000 charge-discharge cycles,the areal capacitance still maintains 93%and 70%at high current densities of 20 and 80 mA cm^(-2),respectively.Moreover,the ACF/PPS/MWCNT-PPy electrode displays over 50%the areal capacitance and maintains it's mechanical stability after annealing at 300℃.The UL-94 test reveals that the highest V-0 flame-retardant performance can be achieved.All these results suggest that the ACF/PPS/MWCNT-PPy composite is a promising material to be used as electrode for supercapacitor with high energy-storage capability and noninflammability.展开更多
The effects of different preheating and annealing temperatures on the surface morphology,microstructure,and optical properties of Cu_(2)ZnSnS_(4)(CZTS) thin films are investigated by controlling the preheating and ann...The effects of different preheating and annealing temperatures on the surface morphology,microstructure,and optical properties of Cu_(2)ZnSnS_(4)(CZTS) thin films are investigated by controlling the preheating and annealing temperatures.The prepared thin films were characterized using X-ray diffraction(XRD),Raman spectroscopy,scanning electron microscopy(SEM),and ultra-violet-visible(UV-Vis) spectroscopy techniques.XRD and Raman spectroscopy showed that a Kesterite structure with a selective orientation along the(112) peak was generated,and the thin films produced at a preheating temperature of 300℃ and annealing temperature of 570℃ had fewer secondary phases,which was beneficial for improving the performance of the solar cells.SEM confirms that the crystallite size increases and then decreases as the temperature increases,and the largest and most uniform crystallite size with the smoothest surface is generated at the above preheating and annealing temperatures.UV-Vis measurements show that the thin films generated at the above temperature have the lowest transmittance and the lowest optical band gap value of 1.46 e V,which is close to the optimal band gap value for solar cells and is suitable as an absorber layer material.展开更多
In this paper,the effects of different concentrations of complexing agent(ammonia)on the surface morphology,composition,structure and photoelectric properties of Cd Zn S films were studied.The results of X-ray diffrac...In this paper,the effects of different concentrations of complexing agent(ammonia)on the surface morphology,composition,structure and photoelectric properties of Cd Zn S films were studied.The results of X-ray diffraction(XRD),scanning electron microscopy(SEM)and UV-visible spectrum showed that the surface morphology of the films became worse and the content of zinc decreased significantly with the increase of ammonia concentration.The crystalline phase of Cd Zn S films was not influenced by the ammonia concentration.Because the film has good absorbance,transmittance greater than 70%and band gap width between 3.5 eV and 3.07 eV,it is suitable to be used as a buffer layer for solar cells.Cd S,Zn O and Zn(OH)_(2) were found in the precipitates at the bottom of the solution,and the formation of these precipitates affected the properties of the Cd Zn S films.展开更多
The present work uses PEO solution to well disperse carbon fiber and identifies percolation thresholds of carbon fiber and carbon black which are used as conductive fillers.The resultant cathode plates have an average...The present work uses PEO solution to well disperse carbon fiber and identifies percolation thresholds of carbon fiber and carbon black which are used as conductive fillers.The resultant cathode plates have an average compressive strength of 27.3 MPa and flexural strength of 29.09 MPa,which demonstrate excellent mechanical properties.The Cu^(2+)removal efficiency was measured at different current densities in EC process with cement-based cathode plate,while the voltage changes were recorded.The results showed that the cement-based cathode plate operated stably and achieved 99.7%removal of 1 L of simulated wastewater with a Cu^(2+)concentration of 200 ppm at a current density of 8 m A/cm^(2)for 1 h.Characterization of floc and tested cathode plates,SEM and EDS analyses,and repeatability testing of the tested plates demonstrate the reusability of the plates,proving that cement-based plates can effectively replace metal cathode plates,reduce the cost of EC and improve the applicability of EC devices.展开更多
LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)cathode material is prepared by sol-gel method and the effects of Nb^(5+)doping and different calcination temperatures on cathode materials were deeply investigated.Structural and morpho...LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)cathode material is prepared by sol-gel method and the effects of Nb^(5+)doping and different calcination temperatures on cathode materials were deeply investigated.Structural and morphological characterizations revealed that the optimal content of 1 mol%Nb^(5+)can stabilize layered structures,mitigate Ni^(2+)migration to Li layers,improve lithium diffusion capacity,and reduce lattice expansion/shrinkage while cycling.And calcination temperature at 800℃can not only ensure good morphology,but also suppress the mixed discharge of lithium and nickel in the internal structure.Electrochemical performance evaluation revealed that Nb^(5+)doping improves the discharge-specific capacity of the material,which is conducive to ameliorating its rate capability and cycle performance.And the material at 800℃exhibits the highest discharge specific capacity,the best magnification performance,low polarizability,and the best cycle reversibility.展开更多
Thermal biology traits reflect thermal adaptations to an environment and can be used to infer responses to climate warming in animal species.Within a widespread genus or species,assessing the latitudinal or altitudina...Thermal biology traits reflect thermal adaptations to an environment and can be used to infer responses to climate warming in animal species.Within a widespread genus or species,assessing the latitudinal or altitudinal gradient of thermal physiological traits is essential to reveal thermal adaptations and determine future vulnerability to climate warming geographically.We determined the thermal biology traits of a cold-climate distributed lizard,Takydromus amurensis,and integrated published thermal biology traits within the genus Takydromus to reveal a preliminary geographical pattern in thermal adaptation.The mean selected body temperature(cloaca temperature;T_(sel)),critical thermal maximum(CT_(max)),critical thermal minimum(CT_(min)),and optimal temperature for locomotion(i.e.,sprint speed;T_(opt)) of T.amurensis were 32.6,45.1,3.1,and 33.4℃,respectively.The resting metabolic rates of T.amurensis were po sitively related to temperature from 18℃ to 38℃.We compared the traits of tropical T.sexlineatus,subtropical T.septentrionalis,and T.wolteri with T.amurensis and found that the CT_(max) and thermal tolerance range(the difference between CT_(max) and CT_(min);TTR) increased toward high latitudes,whereas CT_(min) increased toward low latitudes in these four Takydromus lizards.According to this preliminary pattern,we speculate the species at medium and low latitudes would be more vulnerable to extreme heat events caused by ongoing climate warming.We highlight the importance of integrating thermal biology traits along geographical clues,and its potential contribution to evaluate the vulnerabilities of species in the context of climate warming.展开更多
ZnO_(1-x)S_(x) thin films modified by sulfur doping were prepared on glass substrates by chemical bath deposition(CBD) for studying the effect of thiourea concentration on the thin film properties. The obtained ZnO_(1...ZnO_(1-x)S_(x) thin films modified by sulfur doping were prepared on glass substrates by chemical bath deposition(CBD) for studying the effect of thiourea concentration on the thin film properties. The obtained ZnO_(1-x)S_(x) thin films were characterized by scanning electron microscopy(SEM), which shows the surfaces of ZnO_(1-x)S_(x) thin films deposited under the thiourea concentration of 0.14 M are more compact. X-ray diffraction(XRD) measurement shows that the ZnO_(1-x)S_(x) thin films with hexagonal crystal structure had strong diffraction peaks and better crystallinity. The optical transmittance of the ZnO_(1-x)S_(x) thin films with 0.14 M thiourea concentration is above 80% in the wavelength range of 300-900 nm. According to the measurement results from spectrophotometer, the ZnO_(1-x)S_(x) band gap energy value Eg varies nonlinearly with different S/(S+O) ratio x, and increases with the increase of x. There is a band gap value of 2.97 eV in the ZnO_(1-x)S_(x) thin films deposited under 0.14 M thiourea concentration. Therefore, the thin films have better structural, optical and electric properties, and are more suitable for the buffer layers of copper indium gallium selenide(CIGS) thin film solar cells.展开更多
Novel poly(N-vinyl-2-pyrrolidone) (PVP)-coated nickel ferrite nanocrystals were prepared by simultaneously pyrolyzing nickel(Ⅱ) acetylacetonate (Ni(acac)2) and iron(Ⅲ) acetylacetonate (Fe(acac)3) in N-vinyl-2-pyrrol...Novel poly(N-vinyl-2-pyrrolidone) (PVP)-coated nickel ferrite nanocrystals were prepared by simultaneously pyrolyzing nickel(Ⅱ) acetylacetonate (Ni(acac)2) and iron(Ⅲ) acetylacetonate (Fe(acac)3) in N-vinyl-2-pyrrolidone (NVP). The PVP coating was formed in situ through polymerization of NVP. The crystalline structure of the resultant nickel ferrite was analyzed by high-resolution transmission electron microscopy,electron diffraction patterns,and powder X-ray diffraction. In addition,the valence state of Ni and the metal contents of Ni and Fe in different valence states were analyzed by X-ray photoelectron spectroscopy (XPS),atomic absorption and the phenanthroline method. The surface coating layer of PVP and its binding states were characterized by Fourier transform infrared spectroscopy in combination with XPS. Colloidal stability experiments revealed that the nanocrystals could be dispersed well in both phosphate-buffered saline and Dulbecco's Modified Eagle Medium.展开更多
Although the Songnen Plain in the northeastern China was developed relatively late in the temperate zone of the world, its eco-environment has changed greatly. This paper analyzes the changes of land cover and the rat...Although the Songnen Plain in the northeastern China was developed relatively late in the temperate zone of the world, its eco-environment has changed greatly. This paper analyzes the changes of land cover and the rates and trends ofdesertification during the past 100 years in the Songnen Plain. According to the macroscopic analysis, we find that the eco-environment in the plain has reached to the threshold of catastrophic change since the 1950s. The Thom Needle Catastrophic Model was used to determine and validate this conclusion. Human activities, including large-scale construction projects, such as huge dams and dikes, and excessive grazing were the primary factors contributing to regional eco-environmental catastrophe. And irrational reclamation of the wilderness also affected the eco-environmental change. The results reveal the complex human-land interactions.展开更多
基金Project supported by the National Natural Science Foundation of China(51672257,51872269)。
文摘A new kind of apatite-type red-emitting Ba_(2)La_(8)(GeO_(4))_(6)O_(2):Eu^(3+)phosphor was prepared by high temperature solid-state method.The Rietveld analysis based on the powder diffraction data shows that Ba_(2)La_(8)(GeO_(4))_(6)O_(2):Eu^(3+)phosphors possess a pure apatite phase without any impurity.The emission spectrum of Ba_(2)La_(8)(GeO_(4))_(6)O_(2):Eu^(3+)phosphor consists of two bands,an orange emission band from 500 to 600 nm and a red emission band from 600 to 680 nm.By varying the amount of the doped europium ions from 0.02 to 0.14 mol,it is found that the luminescent properties of this rare earth phosphor are the best when the concentration of europium ion is 0.08 mol.The optimum concentration is eventually proved to be 0.08 mol.The Eu^(3+)doping dependent luminescence quenching can be further ascribed to dipole-quadrupole interactions.The quantum yield of Ba_(2)La_(7.92)(GeO_(4))_(6)O_(2):0.08 Eu^(3+)is 37.23%.The CIE analysis confirms a reddish emission in the near ultraviolet(n-UV)excitation.All these above properties of the phosphor can help in contribution of promoting white light-emitting diode.
基金supported by the Science and Technology Innovation Development Program (No.70304901)。
文摘To evaluate the impact of zinc sulfate(ZnSO_(4)) concentration on the structural properties of the films,Cd_(1-x)Zn_(x)S thin films were formed on glass substrates using chemical bath deposition(CBD) in this study.The effect of ZnSO_(4) precursor concentration on the surface morphology,optical properties,and morphological structure of the Cd_(1-x)Zn_(x)S films was investigated.To study the impact of zinc doping content on the performance metrics of Cu(In_(1-x)Ga_(x))Se_(2)(CIGS)cells in the experimental group and to improve the buffer layer thickness,simulations were run using one-dimensional solar cell capacitance simulator(SCAPS-1D) software.
文摘Background The genome of the severe acute respiratory syndrome-associated coronavirus ( SARS-CoV) includes sequences encoding the putative protein X4 ( ORF8, ORF7a), consisting of 122 amino acids. The deduced sequence contains a probable cleaved signal peptide sequence and a C-terminal transmembrane helix, indicating that protein X4 is likely to be a type I membrane protein. This study was conducted to demonstrate whether the protein X4 was expressed and its essential function in the process of SARS-CoV infection. Methods The prokaryotic and eukaryotic protein X4-expressing plasmids were constructed. Recombinant soluble protein X4 was purified from E. coli using ion exchange chromatography, and the preparation was injected into chicken for rising specific polyclonal antibodies. The expression of protein X4 in SARS-CoV infected Vero E6 cells and lung tissues from patients with SARS was performed using immunofluorescence assay and immunohistochemistry technique. The preliminary function of protein X4 was evaluated by treatment with and over-expression of protein X4 in cell lines. Western blot was employed to evaluate the expression of protein X4 in SARS-CoV particles. Results We expressed and purified soluble recombinant protein X4 from E. coli, and generated specific antibodies against protein X4. Western blot proved that the protein X4 was not assembled in the SARS-CoV particles. Indirect immunofluorescence assays revealed that the expression of protein X4 was detected at 8 hours after infection in SARS-CoV-infected Vero E6 cells. It was also detected in the tung tissues from patients with SARS. Treatment with and overexpression of protein X4 inhibited the growth of Balb/c 313 cells as determined by cell counting and MTT assays. Conclusion The results provide the evidence of protein X4 expression following SARS-CoV infection, and may facilitate further investigation of the immunopathological mechanism of SARS.
基金supported by the Key Laboratory of Testing and Tracing of Rare Earth Products for State Market Regulation,Jiangxi University of Science and Technology(No.TTREP2022YB04)the National Natural Science Foundation of China(Nos.51872269 and 52078394)+4 种基金the Science and Technology Research Project of Hubei Provincial Department of Education(No.B2021091)Key Laboratory for New Textile Materials and Applications of Hubei Province,Wuhan Textile University(No.FZXCL202107)the Open Project Program of High-Tech Organic Fibers Key Laboratory of Sichuan ProvinceChina and National Project Cultivation Plan of Wuhan Textile Universitysupported by the Graduate Innovation Fund Project of Wuhan Textile University。
文摘As a new type of light-collecting and luminescent material,all-inorganic cesium lead halide CsPbX_(3)(X=Cl,Br,I)perovskite nanocrystals(NCs)are expected to have a wide range of applications in the fields of photovoltaics,optoelectronics,and fluorescence anti-counterfeiting,etc.Therefore,improving the fluorescence performance and stability of CsPbX_(3)perovskite NCs to prompt their applications would promise both fundamental and practical significance for in-depth research in the field of halide perovskites.In this paper,we developed a modification strategy to introduce a halogen source,zinc bromide(ZnBr_(2))in hexane,to CsPbX_(3)perovskite that can be conducted under atmospheric conditions with reduced reaction cost and easier operation.The first work in this paper was to apply the modification strategy to CsPbI_(3)nanowires(NWs).Compared with the untreated NWs,the ZnBr_(2)/hexane modified CsPbI_(3)NWs exhibited better fluorescence properties.Subsequently,based on the study of perovskite NWs,we investigated perovskite nanocrystal-CsPbI_(3)nanorods(NRs)with different morphologies and sizes.It was found that the luminescence properties of nanorods(NRs)were superior.Later,we infiltrated the modified NRs into the aramid/polyphenylene sulfide(ACFs/PPS)composite paper yielded from our previous work to study its fluorescence performance for anti-counterfeiting.Their luminescence properties under ultraviolet light irradiation enable better performance in fluorescence anti-counterfeiting.The ZnBr_(2)/hexane modification strategy and the applications studied in this work will expand the scope of perovskite research,laying the foundation for the applications of fluorescent anti-counterfeiting,nano-photoelectric devices,and fluorescent composite materials.
基金The authors thank the financial support from Key Research and Development Plan of Hubei Province(2020BCB068).
文摘In this paper,an aramid chopped fiber,so-called(ACF)/polyphenylene sulfide(PPS)composite,containing multi-walled carbon nanotubes(MWCNT),and in situ polymerized polypyrrole(PPy)was designed and fabricated,to be applied as a paper based electrode.The ACF/PPS/MWCNT-PPy electrode features highly porous paper-like structure with excel-lent electrochemical activity,rendering it a high areal capacitance of~3205 mF cm^(-2) at a current density of 5 mA cm^(-2).After 5000 charge-discharge cycles,the areal capacitance still maintains 93%and 70%at high current densities of 20 and 80 mA cm^(-2),respectively.Moreover,the ACF/PPS/MWCNT-PPy electrode displays over 50%the areal capacitance and maintains it's mechanical stability after annealing at 300℃.The UL-94 test reveals that the highest V-0 flame-retardant performance can be achieved.All these results suggest that the ACF/PPS/MWCNT-PPy composite is a promising material to be used as electrode for supercapacitor with high energy-storage capability and noninflammability.
基金supported by the Tianjin Municipal Education Commission (No.70304901)。
文摘The effects of different preheating and annealing temperatures on the surface morphology,microstructure,and optical properties of Cu_(2)ZnSnS_(4)(CZTS) thin films are investigated by controlling the preheating and annealing temperatures.The prepared thin films were characterized using X-ray diffraction(XRD),Raman spectroscopy,scanning electron microscopy(SEM),and ultra-violet-visible(UV-Vis) spectroscopy techniques.XRD and Raman spectroscopy showed that a Kesterite structure with a selective orientation along the(112) peak was generated,and the thin films produced at a preheating temperature of 300℃ and annealing temperature of 570℃ had fewer secondary phases,which was beneficial for improving the performance of the solar cells.SEM confirms that the crystallite size increases and then decreases as the temperature increases,and the largest and most uniform crystallite size with the smoothest surface is generated at the above preheating and annealing temperatures.UV-Vis measurements show that the thin films generated at the above temperature have the lowest transmittance and the lowest optical band gap value of 1.46 e V,which is close to the optimal band gap value for solar cells and is suitable as an absorber layer material.
基金supported by the Fund for Creative Research Groups。
文摘In this paper,the effects of different concentrations of complexing agent(ammonia)on the surface morphology,composition,structure and photoelectric properties of Cd Zn S films were studied.The results of X-ray diffraction(XRD),scanning electron microscopy(SEM)and UV-visible spectrum showed that the surface morphology of the films became worse and the content of zinc decreased significantly with the increase of ammonia concentration.The crystalline phase of Cd Zn S films was not influenced by the ammonia concentration.Because the film has good absorbance,transmittance greater than 70%and band gap width between 3.5 eV and 3.07 eV,it is suitable to be used as a buffer layer for solar cells.Cd S,Zn O and Zn(OH)_(2) were found in the precipitates at the bottom of the solution,and the formation of these precipitates affected the properties of the Cd Zn S films.
基金Funded by the National Natural Science Foundation of China (No.52078394)the Key Research and Development Program of Hubei Provincial (No.2020BAB081)。
文摘The present work uses PEO solution to well disperse carbon fiber and identifies percolation thresholds of carbon fiber and carbon black which are used as conductive fillers.The resultant cathode plates have an average compressive strength of 27.3 MPa and flexural strength of 29.09 MPa,which demonstrate excellent mechanical properties.The Cu^(2+)removal efficiency was measured at different current densities in EC process with cement-based cathode plate,while the voltage changes were recorded.The results showed that the cement-based cathode plate operated stably and achieved 99.7%removal of 1 L of simulated wastewater with a Cu^(2+)concentration of 200 ppm at a current density of 8 m A/cm^(2)for 1 h.Characterization of floc and tested cathode plates,SEM and EDS analyses,and repeatability testing of the tested plates demonstrate the reusability of the plates,proving that cement-based plates can effectively replace metal cathode plates,reduce the cost of EC and improve the applicability of EC devices.
文摘LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)cathode material is prepared by sol-gel method and the effects of Nb^(5+)doping and different calcination temperatures on cathode materials were deeply investigated.Structural and morphological characterizations revealed that the optimal content of 1 mol%Nb^(5+)can stabilize layered structures,mitigate Ni^(2+)migration to Li layers,improve lithium diffusion capacity,and reduce lattice expansion/shrinkage while cycling.And calcination temperature at 800℃can not only ensure good morphology,but also suppress the mixed discharge of lithium and nickel in the internal structure.Electrochemical performance evaluation revealed that Nb^(5+)doping improves the discharge-specific capacity of the material,which is conducive to ameliorating its rate capability and cycle performance.And the material at 800℃exhibits the highest discharge specific capacity,the best magnification performance,low polarizability,and the best cycle reversibility.
基金supported by National Natural Science Foundation of China (31870391 and 31500324)supported by Youth Innovation Promotion Association CAS (No.2019085)。
文摘Thermal biology traits reflect thermal adaptations to an environment and can be used to infer responses to climate warming in animal species.Within a widespread genus or species,assessing the latitudinal or altitudinal gradient of thermal physiological traits is essential to reveal thermal adaptations and determine future vulnerability to climate warming geographically.We determined the thermal biology traits of a cold-climate distributed lizard,Takydromus amurensis,and integrated published thermal biology traits within the genus Takydromus to reveal a preliminary geographical pattern in thermal adaptation.The mean selected body temperature(cloaca temperature;T_(sel)),critical thermal maximum(CT_(max)),critical thermal minimum(CT_(min)),and optimal temperature for locomotion(i.e.,sprint speed;T_(opt)) of T.amurensis were 32.6,45.1,3.1,and 33.4℃,respectively.The resting metabolic rates of T.amurensis were po sitively related to temperature from 18℃ to 38℃.We compared the traits of tropical T.sexlineatus,subtropical T.septentrionalis,and T.wolteri with T.amurensis and found that the CT_(max) and thermal tolerance range(the difference between CT_(max) and CT_(min);TTR) increased toward high latitudes,whereas CT_(min) increased toward low latitudes in these four Takydromus lizards.According to this preliminary pattern,we speculate the species at medium and low latitudes would be more vulnerable to extreme heat events caused by ongoing climate warming.We highlight the importance of integrating thermal biology traits along geographical clues,and its potential contribution to evaluate the vulnerabilities of species in the context of climate warming.
基金supported by the Natural Science Foundation of Tianjin (No.18JCYBJC95400)。
文摘ZnO_(1-x)S_(x) thin films modified by sulfur doping were prepared on glass substrates by chemical bath deposition(CBD) for studying the effect of thiourea concentration on the thin film properties. The obtained ZnO_(1-x)S_(x) thin films were characterized by scanning electron microscopy(SEM), which shows the surfaces of ZnO_(1-x)S_(x) thin films deposited under the thiourea concentration of 0.14 M are more compact. X-ray diffraction(XRD) measurement shows that the ZnO_(1-x)S_(x) thin films with hexagonal crystal structure had strong diffraction peaks and better crystallinity. The optical transmittance of the ZnO_(1-x)S_(x) thin films with 0.14 M thiourea concentration is above 80% in the wavelength range of 300-900 nm. According to the measurement results from spectrophotometer, the ZnO_(1-x)S_(x) band gap energy value Eg varies nonlinearly with different S/(S+O) ratio x, and increases with the increase of x. There is a band gap value of 2.97 eV in the ZnO_(1-x)S_(x) thin films deposited under 0.14 M thiourea concentration. Therefore, the thin films have better structural, optical and electric properties, and are more suitable for the buffer layers of copper indium gallium selenide(CIGS) thin film solar cells.
基金supported by the National Natural Science Foundation of China (20640430564 and 20820102035)the Knowledge Innovation Program of the Chinese Academy of Sciences (KJCX2-YW-M15)the Ministry of Health (2008ZX10001-014)
文摘Novel poly(N-vinyl-2-pyrrolidone) (PVP)-coated nickel ferrite nanocrystals were prepared by simultaneously pyrolyzing nickel(Ⅱ) acetylacetonate (Ni(acac)2) and iron(Ⅲ) acetylacetonate (Fe(acac)3) in N-vinyl-2-pyrrolidone (NVP). The PVP coating was formed in situ through polymerization of NVP. The crystalline structure of the resultant nickel ferrite was analyzed by high-resolution transmission electron microscopy,electron diffraction patterns,and powder X-ray diffraction. In addition,the valence state of Ni and the metal contents of Ni and Fe in different valence states were analyzed by X-ray photoelectron spectroscopy (XPS),atomic absorption and the phenanthroline method. The surface coating layer of PVP and its binding states were characterized by Fourier transform infrared spectroscopy in combination with XPS. Colloidal stability experiments revealed that the nanocrystals could be dispersed well in both phosphate-buffered saline and Dulbecco's Modified Eagle Medium.
基金Under the auspices of the Key Project of Chinese Academy of Sciences (No. KZCX2)
文摘Although the Songnen Plain in the northeastern China was developed relatively late in the temperate zone of the world, its eco-environment has changed greatly. This paper analyzes the changes of land cover and the rates and trends ofdesertification during the past 100 years in the Songnen Plain. According to the macroscopic analysis, we find that the eco-environment in the plain has reached to the threshold of catastrophic change since the 1950s. The Thom Needle Catastrophic Model was used to determine and validate this conclusion. Human activities, including large-scale construction projects, such as huge dams and dikes, and excessive grazing were the primary factors contributing to regional eco-environmental catastrophe. And irrational reclamation of the wilderness also affected the eco-environmental change. The results reveal the complex human-land interactions.
