A simple two-step hydrothermal method synthesized four different CdS/Fe_(3)O_(4)photocatalysts with varying ratios of mass of CdS to Fe_(3)O_(4).The composition and morphology of the prepared samples were investigated...A simple two-step hydrothermal method synthesized four different CdS/Fe_(3)O_(4)photocatalysts with varying ratios of mass of CdS to Fe_(3)O_(4).The composition and morphology of the prepared samples were investigated using X-ray diffraction(XRD),Raman spectrum,X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).Solid UV reflectance spectra testing found that CdS/Fe_(3)O_(4)nanocomposites had good light absorption throughout the spectral range,promoting their photocatalytic properties.Under visible light irradiation,CdS/Fe_(3)O_(4)(2∶5)with a mass ratio of 2∶5 exhibited excellent photocatalytic perfor-mance,with a degradation rate of 98.8%for rhodamine B.Furthermore,after five cycles of photocatalytic degrada-tion reaction,the rhodamine B degradation rate remained at 96.2%,indicating that the photocatalysts have good pho-tocatalytic stability.展开更多
[ Objective] Study on the photosynthesis and fluorescence characteristics in peony under water stress. [ Method ] The two peony varieties Huhong and Luoyanghong were treated by different water stress for determining t...[ Objective] Study on the photosynthesis and fluorescence characteristics in peony under water stress. [ Method ] The two peony varieties Huhong and Luoyanghong were treated by different water stress for determining the photosynthesis and fluorescence characteristics. [ Result ] With the aggravation of water stress, the net photosynthetic rate (Pn) and stomatal conductance (Gs) decreased, while the intercellular CO2 concentration (Ci) increased. Drought could decrease Pn, constrain gas exchange and change the daily photosynthesis. Fo of peony leaf increased and Fv/Fm decreased under water stress especially water logging, causing the inactivation of the PS II reaction center, and the chlorophyll fluorescence characters gradually recovered until afternoon. [ Conclusion] The 75% soil relative water content (SRWC) is the best condition for growth of peony. Compared with drought, water logging is more unfit for the growth of peony. For the two varieties, Huhong assumed more tolerance to drought, accordingly more adaptability.展开更多
A series of WO3 samples with different crystalline phases were prepared by the thermal decomposition method from ammonium tungstate hydrate.X-ray diffraction(XRD),scanning electron microscopy(SEM),high-resolution ...A series of WO3 samples with different crystalline phases were prepared by the thermal decomposition method from ammonium tungstate hydrate.X-ray diffraction(XRD),scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM),X-ray photoelectron spectroscopy,and N2 adsorption-desorption were used to characterize the crystalline phase,morphology,particle size,chemical composition,and surface area of the WO3 samples.The formation of hexagonal(h-WO3) and monoclinic(m-WO3) crystal structures of WO3 at different temperatures or different times was confirmed by XRD.m-WO3 is formed at 600 ℃,while m-WO3 starts to transform into h-WO3 at 800℃.However,h-WO3,which forms at 800℃,may transform into m-WO3 by increasing the calcination temperature to 1000℃.SEM results indicate that m-WO3 particles exhibit a bulky shape with heavy aggregates,while h-WO3 particles exhibit a rod-like shape.Moreover,m-WO3 crystals are sporadically patched on the surface of the h-WO3 rod-like particles,resulting in the exposure of both m-WO3 and h-WO3 on the surface.It is observed that the monoclinic phase(m-WO3)/hexagonal phase(h-WO3) junction was fabricated by tuning the calcination temperature and calcination time.The relative ratios between m-WO3 and h-WO3 in the phase junction can readily be tailored by control of the calcination time.The photocatalytic activities of WO3 with different crystalline phases were evaluated by the photocatalytic degradation of rhodamine B as a model pollutant.A higher photocatalytic activity was observed in the WO3 sample with the m-WO3/h-WO3junction as compared with the sample with only m-WO3.The improvement of photocatalytic activity can be attributed to the reduction of the electron-hole recombination rate owing to the formation of the phase junction,whose presence has been confirmed by HRTEM and photoluminescence spectra.展开更多
We investigate the fluorescence quenching of Rhodamine 6G (R6G), a well known laser dye with a high fluorescence quantum yield, by as-synthesized graphene oxide (GO) in aqueous solution, which is found to be rathe...We investigate the fluorescence quenching of Rhodamine 6G (R6G), a well known laser dye with a high fluorescence quantum yield, by as-synthesized graphene oxide (GO) in aqueous solution, which is found to be rather efficient. By means of steady-state and time-resolved fluorescence spectroscopy combined with detailed analysis about the linear absorption vari- ation for this R6G-GO system, the pertinent quenching mechanism has been elucidated to be a combination of dynamic and static quenching. Possible ground-state complexes be- tween R6G and GO during the static quenching have also been suggested. Furthermore, the direction of photoindueed electron transfer between R6G and GO has been discussed.展开更多
The design and construction of heterojunction photocatalysts,which possess a staggered energy band structure and appropriate interfacial contact,is an effective way to achieve outstanding photocatalytic performance.In...The design and construction of heterojunction photocatalysts,which possess a staggered energy band structure and appropriate interfacial contact,is an effective way to achieve outstanding photocatalytic performance.In this study,2D/2D BiOBr/g‐C_(3)N_(4)heterojunctions were successfully obtained by a convenient in situ self‐assembly route.Under simulated sunlight irradiation,99%of RhB(10 mg·L–1,100 mL)was efficiently degraded by 1.5‐BiOBr/g‐C_(3)N_(4)within 30 min,which is better than the performance of both BiOBr and g‐C_(3)N_(4),and it has superior stability.In addition,the composite also exhibits enhanced photocatalytic activity for H2 production.The enhanced activity can be attributed to the intimate interface contact,the larger surface area,and the highly efficient separation of photoinduced electron–hole pairs.Based on the experimental results,a novel S‐scheme model was proposed to illuminate the transfer process of charge carriers.This study presents a simple way to develop novel step‐scheme photocatalysts for environmental and related applications.展开更多
Two novel rhodamine-based fluorescence enhanced molecular probes (RA1 and RA2) were synthesized, which were both designed as comparative fiuoroionophore and chromophore for the optical detection of Hg^2+. The recog...Two novel rhodamine-based fluorescence enhanced molecular probes (RA1 and RA2) were synthesized, which were both designed as comparative fiuoroionophore and chromophore for the optical detection of Hg^2+. The recognizing behaviors were investigated both experimentally and computationally. They exhibited high selectivity and sensitivity for Hg^2+ over other commonly coexistent metal ions in CH3CN/H2O (1:1, V/V) solution. Test shows that hydroxy benzene of rich electron was beneficial to the chelate of Hg^2+ with sensors. The detection limit was measured to be at least 0.14 p.mol/L. After addition of Hg^2+, the color changed from colourless to pink, which was easily and hydrogel sensor. detected by the naked eye in both solution展开更多
The surface plasmonic resonance(SPR)effect of Bi can effectively improve the light absorption abilities and photogenerated charge carrier separation rate.In this study,a novel ternary heterojunction of g-C3N4/Bi2MoO6/...The surface plasmonic resonance(SPR)effect of Bi can effectively improve the light absorption abilities and photogenerated charge carrier separation rate.In this study,a novel ternary heterojunction of g-C3N4/Bi2MoO6/Bi(CN/BMO/Bi)hollow microsphere was successfully fabricated through solvothermal and in situ reduction methods.The results revealed that the optimal ternary 0.4 CN/BMO/9 Bi photocatalyst exhibited the highest photocatalytic efficiency toward rhodamine B(RhB)degradation with nine times that of pure BMO.The DRS and valence band of the X-ray photoelectron spectroscopy spectrum demonstrate that the band structure of 0.4 CN/BMO/9 Bi is a z-scheme structure.Quenching experiments also provided solid evidence that the·O^2-(at-0.33 eV)is the main species during dye degradation,and the conduction band of g-C3N4 is only the reaction site,demonstrating that the transfer of photogenerated charge carriers of g-C3N4/Bi2 MoO 6/Bi is through an indirect z-scheme structure.Thus,the enhanced photocatalytic performance was mainly ascribed to the synergetic effect of heterojunction structures between g-C3N4 and Bi2MoO6 and the SPR effect of Bi doping,resulting in better optical absorption ability and a lower combination rate of photogenerated charge carriers.The findings in this work provide insight into the synergism of heterostructures and the SPR absorption ability in wastewater treatment.展开更多
The transmission and distribution of moisture in cement-based materials are of great significance to the properties and durability of materials. Traditional macro-humidity monitoring equipment in civil engineering can...The transmission and distribution of moisture in cement-based materials are of great significance to the properties and durability of materials. Traditional macro-humidity monitoring equipment in civil engineering cannot capture the microscale humidity inside cement-based materials in situ. In this paper, a method of using rhodamine 6G fluorescence to characterize the change in relative humidity in cement-based materials is proposed. Two kinds of moulding processes are designed, which are premixed and smeared after moulding, and the optimal preparation concentration is explored. The results showed that rhodamine 6G can reflect the relative humidity of cement-based materials in situ by its fluorescence intensity and had little effect on the hydration heat release and hydration products of cement-based materials;the fluorescence intensity was much higher when the internal relative humidity was 63% and 75%. The research results lead the application of polymer materials in the field of traditional building materials, help to explore the performance evolution law of cement-based materials in micro scale, and have important significance for the evolution from single discipline to interdisciplinary.展开更多
The contents of total phenolics and extractable condensed tannins in the leaves, twigs and stem bark of Canarium album were determined. The structural heterogeneity of condensed tannins from stem bark was characterize...The contents of total phenolics and extractable condensed tannins in the leaves, twigs and stem bark of Canarium album were determined. The structural heterogeneity of condensed tannins from stem bark was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and nuclear magnetic resonance (NMR) analyses The results show the predominance of signals representative of procyanidins and prodelphinidins. In addition, epicatechin and epigallocatechin polymers with galloylated procyanidin or prodelphinidin were also observed. The tannins were screened for their potential antioxidant activities using l,l-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) model systems. Tannins extracted from leaves, twigs and stem bark all showed a very good DPPH radical scavenging activity and ferric reducing power.展开更多
Hierarchical TiO2 hollow nanoboxes(TiO2‐HNBs)assembled from TiO2 nanosheets(TiO2‐NSs)show improved photoreactivity when compared with the building blocks of discrete TiO2‐NSs.However,TiO2‐HNBs can only be excited ...Hierarchical TiO2 hollow nanoboxes(TiO2‐HNBs)assembled from TiO2 nanosheets(TiO2‐NSs)show improved photoreactivity when compared with the building blocks of discrete TiO2‐NSs.However,TiO2‐HNBs can only be excited by ultraviolet light.In this paper,visible‐light‐responsive N and S co‐doped TiO2‐HNBs were prepared by calcining the mixture of cubic TiOF2 and methionine(C5H11NO2S),a N‐and S‐containing biomacromolecule.The effect of calcination temperature on the structure and performance of the TiO2‐HNBs was systematically studied.It was found that methionine can prevent TiOF2‐to‐anatase TiO2 phase transformation.Both N and S elements are doped into the lattice of TiO2‐HNBs when the mixture of TiOF2 and methionine undergoes calcination at 400°C,which is responsible for the visible‐light response.When compared with that of pure 400°C‐calcined TiO2‐HNBs(T400),the photoreactivity of 400°C‐calcined methionine‐modified TiO2‐HNBs(TM400)improves 1.53 times in photocatalytic degradation of rhodamine‐B dye under visible irradiation(?>420 nm).The enhanced visible photoreactivity of methionine‐modified TiO2‐HNBs is also confirmed by photocatalytic oxidation of NO.The successful doping of N and S elements into the lattice of TiO2‐HNBs,resulting in the improved light‐harvesting ability and efficient separation of photo‐generated electron‐hole pairs,is responsible for the enhanced visible photocatalytic activity of methionine‐modified TiO2‐HNBs.The photoreactivity of methionine modified TiO2‐HNBs remains nearly unchanged even after being recycled five times,indicating its promising use in practical applications.展开更多
The fluorescence quenching of Rhodamine 6G (R6G) by graphene oxide (GO) was interrogated by R6G fluorescence measurements using a set of controlled GO samples with varied C/O ratios as the quencher. The carbonyl g...The fluorescence quenching of Rhodamine 6G (R6G) by graphene oxide (GO) was interrogated by R6G fluorescence measurements using a set of controlled GO samples with varied C/O ratios as the quencher. The carbonyl groups on the GO nanosheet turned to play a dominant role in quenching the R6G fluorescence. The quenching in the static regime can be described by the "sphere of action" model. The significant absorption of the R6G fluorescence by the ground-state complex formed between R6G and GO was identified to be responsible for the static quenching mechanisms in quenching. This work offers the R6G/GO system. insights into the fluorescence展开更多
A type of poriferous TiO2 material was prepared using cetyl trimethyl ammonium bromide as a template agent and butyl tetra titanate as a precursor. Through studying the photocatalytic kinetic activity of Rhodamine B p...A type of poriferous TiO2 material was prepared using cetyl trimethyl ammonium bromide as a template agent and butyl tetra titanate as a precursor. Through studying the photocatalytic kinetic activity of Rhodamine B photocatalytic degradation reaction with a UV-1601PC ultraviolet-visible spectrophotometer, the photocatalytic degradation process of Rhodamine B was found to not correspond to the first-order kinetic process completely. According to the reaction phenomenon, the photocatalytic degradation process of Rhodamine B with poriferous TiO2 involved two irreversible reactions. The kinetic model was tested using experimental data.展开更多
Objective To analyze the effects of Dan Huang Ming Mu Recipe(DHMMR)(a pharmaceutical preparation from herbs and having the function of replenishing vital essence,removing heat,promoting blood circulation and excreting...Objective To analyze the effects of Dan Huang Ming Mu Recipe(DHMMR)(a pharmaceutical preparation from herbs and having the function of replenishing vital essence,removing heat,promoting blood circulation and excreting pathogenic water) on diabetic retinopathy(DR) after retinal laser photocoagulation through regulating the expression of vascular endothelial growth factor(VEGF) and pigment epithelium-derived factor(PEDF).Methods Forty male Brown Norway(BN) rats were randomly divided into blank group(group A,10 BN rats) and model group(30 BN rats).DR models were induced by 40 mg/kg streptozotocin(STZ) and the body weight and blood glucose of rats were monitored.After 12-week injection,fluorescein fundus angiography(FFA) and histopathological examination were detected to confirm the successful establishment of DR models.Subsequently,the right eyes of model group rats were conducted retinal laser photocoagulation with the left eyes having no retinal laser photocoagulation and rats of the model group were randomly divided into group B(the model control group),group C(the positive control group),and group D(the DHMMR group),with 10 rats in each group.Rats of the group A and the group B were given vehicle,and the group C were given calcium dobesilate suspension by gavage,and the group D were given DHMMR by gavage.After 4-week gavage,FFA was carried out to observe the fundus microvascular change.Then,the rats were sacrificed to do histopathological examinations and the serum levels of P-selectin,cAMP,cGMP,and the relative expression of the protein of VEGF and PEDF in retina were detected.Results After 12-week STZ injection,the blood glucose of the model group were pronouncedly higher than the blank group(P < 0.01).Fundus micro-hemangioma changes were observed in the rats of the model group through FFA,and the rats of the blank group did not see any changes.The pictures of HE staining showed that the retinal structure of the model group was more disordered than the blank group.After 4-week gavage,treatments with DHMMR showed dramatic reduction of serum levels of Pselectin,cAMP and cGMP compared with the group B(P < 0.01).FFA and histopathological examinations of DHMMR-treated rats revealed significantly suppression of retinal edema,fundus microvascular destruction and retinal destruction distinguishing from the group B.And the relative expression of VEGF protein of the group D and the group A was markedly lower than that of the group B(P < 0.01).The relative expression of PEDF protein of the group D and the group A was dramatically higher than that of the group B to the contrary(P < 0.01).Conclusions DHMMR demonstrates pronounced suppressive effects on the progression of DR after retinal laser photocoagulation,through down-regulating VEGF and upregulating PEDF.展开更多
Au@Au@Ag double shell nanoparticles were fabricated and characterized using TEM,STEM-mapping and UV-Vis methods.Using crystal violet as Raman probe,the surface-enhanced Raman scattering(SERS)activity of the as-prepare...Au@Au@Ag double shell nanoparticles were fabricated and characterized using TEM,STEM-mapping and UV-Vis methods.Using crystal violet as Raman probe,the surface-enhanced Raman scattering(SERS)activity of the as-prepared Au@Au@Ag nanoparticles was studied by comparing to Au,Au@Ag and Au@Au core-shell nanoparticles which were prepared by the same methods.Moreover,it can be found that the SERS activity was enhanced obviously by introduction of NaCl and the concentrations of NaCl played a key role in SERS detection.With an appropriate concentration of NaCl,the limit of detection as low as 10^(-10)mol/L crystal violet can be achieved.The possible enhanced mechanism was also discussed.Furthermore,with simple sample pretreatment,the detection limit of 5μg/g Rhodamine B(RhB)in chili powders can be achieved.The results highlight the potential utility of Au@Au@Ag for detection of illegal food additives with low concentrations.展开更多
文摘A simple two-step hydrothermal method synthesized four different CdS/Fe_(3)O_(4)photocatalysts with varying ratios of mass of CdS to Fe_(3)O_(4).The composition and morphology of the prepared samples were investigated using X-ray diffraction(XRD),Raman spectrum,X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).Solid UV reflectance spectra testing found that CdS/Fe_(3)O_(4)nanocomposites had good light absorption throughout the spectral range,promoting their photocatalytic properties.Under visible light irradiation,CdS/Fe_(3)O_(4)(2∶5)with a mass ratio of 2∶5 exhibited excellent photocatalytic perfor-mance,with a degradation rate of 98.8%for rhodamine B.Furthermore,after five cycles of photocatalytic degrada-tion reaction,the rhodamine B degradation rate remained at 96.2%,indicating that the photocatalysts have good pho-tocatalytic stability.
基金the Key Project Foundation of Henan Province (0122012400)the Key Project Foundation of Luoyang City (20011001)~~
文摘[ Objective] Study on the photosynthesis and fluorescence characteristics in peony under water stress. [ Method ] The two peony varieties Huhong and Luoyanghong were treated by different water stress for determining the photosynthesis and fluorescence characteristics. [ Result ] With the aggravation of water stress, the net photosynthetic rate (Pn) and stomatal conductance (Gs) decreased, while the intercellular CO2 concentration (Ci) increased. Drought could decrease Pn, constrain gas exchange and change the daily photosynthesis. Fo of peony leaf increased and Fv/Fm decreased under water stress especially water logging, causing the inactivation of the PS II reaction center, and the chlorophyll fluorescence characters gradually recovered until afternoon. [ Conclusion] The 75% soil relative water content (SRWC) is the best condition for growth of peony. Compared with drought, water logging is more unfit for the growth of peony. For the two varieties, Huhong assumed more tolerance to drought, accordingly more adaptability.
基金supported by the National Natural Science Foundation of China (21573101)the Liaoning Provincial Natural Science Foundation(2014020107)+2 种基金the Program for Liaoning Excellent Talents in University (LJQ2014041)the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry ([2013]1792)the Opening Project of Key Laboratory of Photochemical Conversion and Optoelectronic Materials, TIPC, CAS,the Opening Project of State Key Laboratory of Catalysis, DICP, CAS (N-09-06)~~
文摘A series of WO3 samples with different crystalline phases were prepared by the thermal decomposition method from ammonium tungstate hydrate.X-ray diffraction(XRD),scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM),X-ray photoelectron spectroscopy,and N2 adsorption-desorption were used to characterize the crystalline phase,morphology,particle size,chemical composition,and surface area of the WO3 samples.The formation of hexagonal(h-WO3) and monoclinic(m-WO3) crystal structures of WO3 at different temperatures or different times was confirmed by XRD.m-WO3 is formed at 600 ℃,while m-WO3 starts to transform into h-WO3 at 800℃.However,h-WO3,which forms at 800℃,may transform into m-WO3 by increasing the calcination temperature to 1000℃.SEM results indicate that m-WO3 particles exhibit a bulky shape with heavy aggregates,while h-WO3 particles exhibit a rod-like shape.Moreover,m-WO3 crystals are sporadically patched on the surface of the h-WO3 rod-like particles,resulting in the exposure of both m-WO3 and h-WO3 on the surface.It is observed that the monoclinic phase(m-WO3)/hexagonal phase(h-WO3) junction was fabricated by tuning the calcination temperature and calcination time.The relative ratios between m-WO3 and h-WO3 in the phase junction can readily be tailored by control of the calcination time.The photocatalytic activities of WO3 with different crystalline phases were evaluated by the photocatalytic degradation of rhodamine B as a model pollutant.A higher photocatalytic activity was observed in the WO3 sample with the m-WO3/h-WO3junction as compared with the sample with only m-WO3.The improvement of photocatalytic activity can be attributed to the reduction of the electron-hole recombination rate owing to the formation of the phase junction,whose presence has been confirmed by HRTEM and photoluminescence spectra.
基金This work was supported by the National Basic Research Program of China (No.2010CB923300), the National Natural Science Foundation of China (No.91127042 and No.21173205), the Chinese Academy of Sciences (No.XDB01020000), the FR- FCUC (No.WK2340000012), the USTC-NSRL Joint Funds (No.KY2340000021), and the National Under- graduate Innovative Training Program of Ministry of Education (No.201210358064).
文摘We investigate the fluorescence quenching of Rhodamine 6G (R6G), a well known laser dye with a high fluorescence quantum yield, by as-synthesized graphene oxide (GO) in aqueous solution, which is found to be rather efficient. By means of steady-state and time-resolved fluorescence spectroscopy combined with detailed analysis about the linear absorption vari- ation for this R6G-GO system, the pertinent quenching mechanism has been elucidated to be a combination of dynamic and static quenching. Possible ground-state complexes be- tween R6G and GO during the static quenching have also been suggested. Furthermore, the direction of photoindueed electron transfer between R6G and GO has been discussed.
文摘The design and construction of heterojunction photocatalysts,which possess a staggered energy band structure and appropriate interfacial contact,is an effective way to achieve outstanding photocatalytic performance.In this study,2D/2D BiOBr/g‐C_(3)N_(4)heterojunctions were successfully obtained by a convenient in situ self‐assembly route.Under simulated sunlight irradiation,99%of RhB(10 mg·L–1,100 mL)was efficiently degraded by 1.5‐BiOBr/g‐C_(3)N_(4)within 30 min,which is better than the performance of both BiOBr and g‐C_(3)N_(4),and it has superior stability.In addition,the composite also exhibits enhanced photocatalytic activity for H2 production.The enhanced activity can be attributed to the intimate interface contact,the larger surface area,and the highly efficient separation of photoinduced electron–hole pairs.Based on the experimental results,a novel S‐scheme model was proposed to illuminate the transfer process of charge carriers.This study presents a simple way to develop novel step‐scheme photocatalysts for environmental and related applications.
文摘Two novel rhodamine-based fluorescence enhanced molecular probes (RA1 and RA2) were synthesized, which were both designed as comparative fiuoroionophore and chromophore for the optical detection of Hg^2+. The recognizing behaviors were investigated both experimentally and computationally. They exhibited high selectivity and sensitivity for Hg^2+ over other commonly coexistent metal ions in CH3CN/H2O (1:1, V/V) solution. Test shows that hydroxy benzene of rich electron was beneficial to the chelate of Hg^2+ with sensors. The detection limit was measured to be at least 0.14 p.mol/L. After addition of Hg^2+, the color changed from colourless to pink, which was easily and hydrogel sensor. detected by the naked eye in both solution
基金financially supported by the Science Foundation of China University of Petroleum,Beijing(2462017YJRC048,2462018BJC005)the National Natural Science Foundation of China(51802351)~~
文摘The surface plasmonic resonance(SPR)effect of Bi can effectively improve the light absorption abilities and photogenerated charge carrier separation rate.In this study,a novel ternary heterojunction of g-C3N4/Bi2MoO6/Bi(CN/BMO/Bi)hollow microsphere was successfully fabricated through solvothermal and in situ reduction methods.The results revealed that the optimal ternary 0.4 CN/BMO/9 Bi photocatalyst exhibited the highest photocatalytic efficiency toward rhodamine B(RhB)degradation with nine times that of pure BMO.The DRS and valence band of the X-ray photoelectron spectroscopy spectrum demonstrate that the band structure of 0.4 CN/BMO/9 Bi is a z-scheme structure.Quenching experiments also provided solid evidence that the·O^2-(at-0.33 eV)is the main species during dye degradation,and the conduction band of g-C3N4 is only the reaction site,demonstrating that the transfer of photogenerated charge carriers of g-C3N4/Bi2 MoO 6/Bi is through an indirect z-scheme structure.Thus,the enhanced photocatalytic performance was mainly ascribed to the synergetic effect of heterojunction structures between g-C3N4 and Bi2MoO6 and the SPR effect of Bi doping,resulting in better optical absorption ability and a lower combination rate of photogenerated charge carriers.The findings in this work provide insight into the synergism of heterostructures and the SPR absorption ability in wastewater treatment.
基金Project(2018YFD1101002) supported by the National Key R&D Program of ChinaProject(51308405) supported by the National Natural Science Foundation of China。
文摘The transmission and distribution of moisture in cement-based materials are of great significance to the properties and durability of materials. Traditional macro-humidity monitoring equipment in civil engineering cannot capture the microscale humidity inside cement-based materials in situ. In this paper, a method of using rhodamine 6G fluorescence to characterize the change in relative humidity in cement-based materials is proposed. Two kinds of moulding processes are designed, which are premixed and smeared after moulding, and the optimal preparation concentration is explored. The results showed that rhodamine 6G can reflect the relative humidity of cement-based materials in situ by its fluorescence intensity and had little effect on the hydration heat release and hydration products of cement-based materials;the fluorescence intensity was much higher when the internal relative humidity was 63% and 75%. The research results lead the application of polymer materials in the field of traditional building materials, help to explore the performance evolution law of cement-based materials in micro scale, and have important significance for the evolution from single discipline to interdisciplinary.
基金Project supported by the National Natural Science Foundation of China (No. 30671646)the Program for New Century Excellent Talents in University, China (No. NCET-07-0725)the Program for Innovative Research Team in Science and Technology in Fujian Province University, China
文摘The contents of total phenolics and extractable condensed tannins in the leaves, twigs and stem bark of Canarium album were determined. The structural heterogeneity of condensed tannins from stem bark was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and nuclear magnetic resonance (NMR) analyses The results show the predominance of signals representative of procyanidins and prodelphinidins. In addition, epicatechin and epigallocatechin polymers with galloylated procyanidin or prodelphinidin were also observed. The tannins were screened for their potential antioxidant activities using l,l-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) model systems. Tannins extracted from leaves, twigs and stem bark all showed a very good DPPH radical scavenging activity and ferric reducing power.
基金supported by the National Natural Science Foundation of China(31402137,51672312,21373275)Hubei Province Science Fund for Distinguished Yong Scholars(2013CFA034)+2 种基金the Program for Excellent Talents in Hubei Province(RCJH15001)the Science and Technology Program of Wuhan(2016010101010018)the Fundamental Research Funds for the Central University,South-Central University for Nationalities(CZP17077,CZP18016)~~
文摘Hierarchical TiO2 hollow nanoboxes(TiO2‐HNBs)assembled from TiO2 nanosheets(TiO2‐NSs)show improved photoreactivity when compared with the building blocks of discrete TiO2‐NSs.However,TiO2‐HNBs can only be excited by ultraviolet light.In this paper,visible‐light‐responsive N and S co‐doped TiO2‐HNBs were prepared by calcining the mixture of cubic TiOF2 and methionine(C5H11NO2S),a N‐and S‐containing biomacromolecule.The effect of calcination temperature on the structure and performance of the TiO2‐HNBs was systematically studied.It was found that methionine can prevent TiOF2‐to‐anatase TiO2 phase transformation.Both N and S elements are doped into the lattice of TiO2‐HNBs when the mixture of TiOF2 and methionine undergoes calcination at 400°C,which is responsible for the visible‐light response.When compared with that of pure 400°C‐calcined TiO2‐HNBs(T400),the photoreactivity of 400°C‐calcined methionine‐modified TiO2‐HNBs(TM400)improves 1.53 times in photocatalytic degradation of rhodamine‐B dye under visible irradiation(?>420 nm).The enhanced visible photoreactivity of methionine‐modified TiO2‐HNBs is also confirmed by photocatalytic oxidation of NO.The successful doping of N and S elements into the lattice of TiO2‐HNBs,resulting in the improved light‐harvesting ability and efficient separation of photo‐generated electron‐hole pairs,is responsible for the enhanced visible photocatalytic activity of methionine‐modified TiO2‐HNBs.The photoreactivity of methionine modified TiO2‐HNBs remains nearly unchanged even after being recycled five times,indicating its promising use in practical applications.
基金supported by the Ministry of Science and Technology of China (No.2016YFA0200602)the National Natural Science Foundation of China (No.21573211 and No.21633007)the Fundamental Research Funds for the Central Universities (No.WK2340000063)
文摘The fluorescence quenching of Rhodamine 6G (R6G) by graphene oxide (GO) was interrogated by R6G fluorescence measurements using a set of controlled GO samples with varied C/O ratios as the quencher. The carbonyl groups on the GO nanosheet turned to play a dominant role in quenching the R6G fluorescence. The quenching in the static regime can be described by the "sphere of action" model. The significant absorption of the R6G fluorescence by the ground-state complex formed between R6G and GO was identified to be responsible for the static quenching mechanisms in quenching. This work offers the R6G/GO system. insights into the fluorescence
文摘A type of poriferous TiO2 material was prepared using cetyl trimethyl ammonium bromide as a template agent and butyl tetra titanate as a precursor. Through studying the photocatalytic kinetic activity of Rhodamine B photocatalytic degradation reaction with a UV-1601PC ultraviolet-visible spectrophotometer, the photocatalytic degradation process of Rhodamine B was found to not correspond to the first-order kinetic process completely. According to the reaction phenomenon, the photocatalytic degradation process of Rhodamine B with poriferous TiO2 involved two irreversible reactions. The kinetic model was tested using experimental data.
基金the funding support from the Provincial Natural Science Foundation General Program(No.2015JJ2109)Hunan Province Graduate Student Research Innovation Program(No.CX2018B473)+7 种基金Hunan Traditional Chinese Medicine Scientific Research Program(NO.201463 and NO.2017141)Key Scientific Research Project of Hunan Administration of Traditional Chinese Medicine(NO.201917)University-level Scientific Research Projects of Hunan University of Chinese Medicine(NO.2017029 and NO.2018XJJJ31)The Domestic Firstclass Discipline Construction Project of Chinese Medicine of Hunan University of Chinese MedicineCentral Finance Supported Local High School Construction ProjectState Administration of Traditional Chinese Medicine Ophthalmology Key Discipline Construction ProjectHunan Province Traditional Chinese Medicine Facial Feature Key Discipline Construction ProjectHunan Engineering Technology Research Center for the Prevention and Treatment of Otorhinolaryngologic Diseases and Protection of Visual Function with Chinese Medicine,Hunan Provincial Key Laboratory for the Prevention and Treatment of Ophthalmology and Otolaryngology Diseases with Traditional Chinese Medicine
文摘Objective To analyze the effects of Dan Huang Ming Mu Recipe(DHMMR)(a pharmaceutical preparation from herbs and having the function of replenishing vital essence,removing heat,promoting blood circulation and excreting pathogenic water) on diabetic retinopathy(DR) after retinal laser photocoagulation through regulating the expression of vascular endothelial growth factor(VEGF) and pigment epithelium-derived factor(PEDF).Methods Forty male Brown Norway(BN) rats were randomly divided into blank group(group A,10 BN rats) and model group(30 BN rats).DR models were induced by 40 mg/kg streptozotocin(STZ) and the body weight and blood glucose of rats were monitored.After 12-week injection,fluorescein fundus angiography(FFA) and histopathological examination were detected to confirm the successful establishment of DR models.Subsequently,the right eyes of model group rats were conducted retinal laser photocoagulation with the left eyes having no retinal laser photocoagulation and rats of the model group were randomly divided into group B(the model control group),group C(the positive control group),and group D(the DHMMR group),with 10 rats in each group.Rats of the group A and the group B were given vehicle,and the group C were given calcium dobesilate suspension by gavage,and the group D were given DHMMR by gavage.After 4-week gavage,FFA was carried out to observe the fundus microvascular change.Then,the rats were sacrificed to do histopathological examinations and the serum levels of P-selectin,cAMP,cGMP,and the relative expression of the protein of VEGF and PEDF in retina were detected.Results After 12-week STZ injection,the blood glucose of the model group were pronouncedly higher than the blank group(P < 0.01).Fundus micro-hemangioma changes were observed in the rats of the model group through FFA,and the rats of the blank group did not see any changes.The pictures of HE staining showed that the retinal structure of the model group was more disordered than the blank group.After 4-week gavage,treatments with DHMMR showed dramatic reduction of serum levels of Pselectin,cAMP and cGMP compared with the group B(P < 0.01).FFA and histopathological examinations of DHMMR-treated rats revealed significantly suppression of retinal edema,fundus microvascular destruction and retinal destruction distinguishing from the group B.And the relative expression of VEGF protein of the group D and the group A was markedly lower than that of the group B(P < 0.01).The relative expression of PEDF protein of the group D and the group A was dramatically higher than that of the group B to the contrary(P < 0.01).Conclusions DHMMR demonstrates pronounced suppressive effects on the progression of DR after retinal laser photocoagulation,through down-regulating VEGF and upregulating PEDF.
基金supported by the National Natural Science Foundation of China(No.21505118)the Natural Science Foundation of Jiangsu Province of China(BK 20150438)Postdoctoral Research Funding Program of Jiangsu Province of China(No.1701133C).
文摘Au@Au@Ag double shell nanoparticles were fabricated and characterized using TEM,STEM-mapping and UV-Vis methods.Using crystal violet as Raman probe,the surface-enhanced Raman scattering(SERS)activity of the as-prepared Au@Au@Ag nanoparticles was studied by comparing to Au,Au@Ag and Au@Au core-shell nanoparticles which were prepared by the same methods.Moreover,it can be found that the SERS activity was enhanced obviously by introduction of NaCl and the concentrations of NaCl played a key role in SERS detection.With an appropriate concentration of NaCl,the limit of detection as low as 10^(-10)mol/L crystal violet can be achieved.The possible enhanced mechanism was also discussed.Furthermore,with simple sample pretreatment,the detection limit of 5μg/g Rhodamine B(RhB)in chili powders can be achieved.The results highlight the potential utility of Au@Au@Ag for detection of illegal food additives with low concentrations.