A synergistic system of water falling film dielectric barrier discharge(DBD)plasma and persulfate(PS)was set up and used for oxidizing ciprofloxacin(CIP)in water.Results of reactive species formation in the DBD-only s...A synergistic system of water falling film dielectric barrier discharge(DBD)plasma and persulfate(PS)was set up and used for oxidizing ciprofloxacin(CIP)in water.Results of reactive species formation in the DBD-only system as well as the DBD–PS system verified the PS activation in the DBD system.Influencing factors on CIP degradation and the degradation process were also been studied.The obtained results showed that the presence of PS could greatly improve the degradation and mineralization of CIP and that the degradation efficiency could reach 97.73%after only 40 min treatment with 4 m M PS addition.The increase of PS concentration,the lower CIP concentration,the acidic solution p H and the addition of metal ions(Fe^(2+)and Cu^(2+))enhanced the CIP degradation,while the existence of Cl^(-)and HCO_(3)^(-)had a negative effect.The experiments related to scavenger addition confirmed the contribution of the main reactive species to the CIP oxidation.Three probable degradation pathways were proposed by analyzing the inorganic ions and organic byproducts formed during the CIP degradation.The toxicity evaluation results of the CIP and its intermediates confirmed the effectiveness of the DBD–PS synergistic system.展开更多
We applied under pot-culture conditions and the double-casing pot method to study the characteristics of photosynthetic gas exchange and chlorophyll fluorescence in the leaves of Physocarpus amurensis Maxim(PA) and Ph...We applied under pot-culture conditions and the double-casing pot method to study the characteristics of photosynthetic gas exchange and chlorophyll fluorescence in the leaves of Physocarpus amurensis Maxim(PA) and Physocarpus opulifolius under flooding stress.Our results indicate a significantly higher flooding tolerance of P.opulifolius compared to P.amurensis.Especially in P.amurensis, the limitation of non-stomatal factors played a major role in the advanced stages of flooding stress,observed as a rapid increase of the intercellular CO_2 concentration(C_i) and a decrease of the stomatal limitation value(L_s).The maximal PSII photochemical efficiencies(F_v/F_m) and actual photochemical efficiency(?_(PSII)) in the leaves of P.opulifolius were significantly higher, and the extent of decrease during the flooding process was smaller than in P.amurensis.In addition, the non-chemical quenching(NPQ) in the leaves of P.opulifolius significantly increased from the 10 th day under flooding stress,while the variation of NPQ in the leaves of P.amurensis was much smaller.This indicates that the leaves of P.opulifolius had not only higher PSII photochemical activity, but also improved tolerance to flooding stress, which may be caused by its ability to dissipate excess excitation energy by starting NPQ.At the 16 th day under flooding stress, the PIABSsignificantly decreased with greater extent of decrease than F_v/F_m in the leaves of both Physocarpus,but the decreasing extent of PIABSin P.opulifolius was significantly smaller than in P.amurensis.In the 16 th day under flooding stress, the fluorescence at J and I point(V_J and V_I) in P.amurensis were significantly higher, and the extent of increase in V_J was greater than V_I.However, the variations of V_Jand V_I in the leaves of P.opulifolius were smaller, suggesting that the damage sites of flooding stress to PSII in the leaves of P.amurensis were mainly located in the electron transport process from Q_A at the PSII receptor side to Q_B.Flooding stress reduced the proportion(φ Eo) of luminous energy absorbed by the PSII reaction center for the electron transport following Q_A^-, while the maximum quantum yield(φ Do) of non-photochemical quenching increased.However, the TR_o/RC and ETo/RC in the leaves of P.amurensis decreased accompanied by a dramatic increase of energy(DI_o/RC) from the dissipation in the reaction center.This further indicated that the function of the PSII reaction center in the leaves of P.amurensis was significantly lower than in P.opulifolius.展开更多
This study investigates the effects of cold-acclimation in conferring chilling tolerance in seedlings of the mulberry(Morus alba) variety ‘Qiuyu’. Changes in photosynthesis and antioxidant enzymes in chilling acclim...This study investigates the effects of cold-acclimation in conferring chilling tolerance in seedlings of the mulberry(Morus alba) variety ‘Qiuyu’. Changes in photosynthesis and antioxidant enzymes in chilling acclimatized(CA), and non-acclimatized(NA) seedlings were recorded during chilling stress(3 °C) and a recovery period(25 °C) each for 3 days. The results showed that CA plants had higher net photosynthetic rates(P_n), stomatal conductance(G_s), and maximum photochemical efficiency of photosystem Ⅱ(F_v/F_m) in response to chilling stress compared to NA. The seedlings maintained the same trends during the recovery stage. The responses of Q_A reduction degree (1-q_P) and prime electronic transfer rates(F_o) were lower in acclimatized than in non-acclimatized seedlings. Low-temperature acclimation and chilling stress also caused an increase in leaf proline and soluble sugar contents. Leaf malondialdehyde levels were significantly lower while ascorbate peroxidase(APX) activity was significantly higher in acclimatized seedlings, suggesting that elevated osmolytes and APX confer resistance to chilling temperatures. In this study on the response of mulberry seedlings to chilling stress, we also looked at the recovery process. The response to chilling determines whether mulberry leaves can survive under cold temperatures, while the recovery process determines whether photosynthesis can recover as soon as possible to avoid any secondary damage.展开更多
Intercropping of mulberry(Morus alba L.)and alfalfa(Medicago sativa L.)is a new forestry-grass compound model in China,which can provide high forage yields with high protein.Nitrogen application is one of the importan...Intercropping of mulberry(Morus alba L.)and alfalfa(Medicago sativa L.)is a new forestry-grass compound model in China,which can provide high forage yields with high protein.Nitrogen application is one of the important factors determining the production and quality of this system.To elucidate the advantages of intercropping and nitrogen application,we analyzed the changes of physicochemical properties,enzyme activities,and microbial communities in the rhizosphere soil.We used principal components analysis(PCA)and redundancy discriminators analysis to clarify the relationships among treatments and between treatments and environmental factors,respectively.The results showed that nitrogen application significantly increased pH value,available nitrogen content,soil water content(SWC),and urea(URE)activity in rhizosphere soil of monoculture mulberry.In contrast,intercropping and intercropping+N significantly decreased pH and SWC in mulberry treatments.Nitrogen,intercropping and intercropping+N sharply reduced soil organic matter content and SWC in alfalfa treatments.Nitrogen,intercropping,and intercropping+N increased the values of McIntosh diversity(U),Simpson diversity(D),and Shannon-Weaver diversity(H’)in mulberry treatments.However,PC A scatter plots showed clustering of monoculture mulberry with nitrogen(MNE)and intercropping mulberry without nitrogen(M0).Intercropping reduced both H’and D but nitrogen application showed no effect on diversity of microbial communities in alfalfa.There were obvious differences in using the six types of carbon sources between mulberry and alfalfa treatments.Nitrogen and intercropping increased the numbers of sole carbon substrate in mulberry treatments where the relative use rate exceeded 4%.While the numbers declined in alfalfa with nitrogen and intercropping.RDA indicated that URE was positive when intercropping mulberry was treated with nitrogen,but was negative in monoculture alfalfa treated with nitrogen.Soil pH and SWC were positive with mulberry treatments but were negative with alfalfa treatments.Intercropping with alfalfa benefited mulberry in the absence of nitrogen application.Intercropping with alfalfa and nitrogen application could improve the microbial community function and diversity in rhizosphere soil of mulberry.The microbial community in rhizosphere soil of mulberry and alfalfa is strategically complementary in terms of using carbon sources.展开更多
Fluorescent silk is fundamentally important for the development of future tissue engineering scaffolds.Despite great progress in the preparation of a variety of colored silks,fluorescent silk with enhanced mechanical ...Fluorescent silk is fundamentally important for the development of future tissue engineering scaffolds.Despite great progress in the preparation of a variety of colored silks,fluorescent silk with enhanced mechanical properties has yet to be explored.In this study,we report on the fabrication of intrinsically super-strong fluorescent silk by feeding Bombyx mori silkworm carbon nanodots(CNDs).The CNDs were incorporated into silk fibroin,hindering the conformation transformation,confining crystallization,and inducing orientation of mesophase.The resultant silk exhibited super-strong mechanical properties with breaking strength of 521.9±82.7 MPa and breaking elongation of 19.2±4.3%,improvements of 55.1%and 53.6%,respectively,in comparison with regular silk.The CNDs-reinforced silk displayed intrinsic blue fluorescence when exposed to 405 nm laser and exhibited no cytotoxic effect on cells,suggesting that multi-functional silks would be potentially useful in bioimaging and other applications.展开更多
Estimating spatial variation in crop transpiration coefficients(CTc) and aboveground biomass(AGB)rapidly and accurately by remote sensing can facilitate precision irrigation management in semiarid regions. This study ...Estimating spatial variation in crop transpiration coefficients(CTc) and aboveground biomass(AGB)rapidly and accurately by remote sensing can facilitate precision irrigation management in semiarid regions. This study developed and assessed a novel machine learning(ML) method for estimating CTc and AGB using time-series unmanned aerial vehicle(UAV)-based multispectral vegetation indices(VIs)of maize under several irrigation treatments at the field scale. Four ML regression methods: multiple linear regression(MLR), support vector regression(SVR), random forest regression(RFR), and adaptive boosting regression(ABR), were used to address the complex relationship between CTcand VIs. AGB was then estimated using exponential, logistic, sigmoid, and linear equations because of their clear mathematical formulations based on the optimal CTcestimation model. The UAV VIs-derived CTcusing the RFR estimation model yielded the highest accuracy(R^(2)= 0.91, RMSE = 0.0526, and n RMSE = 9.07%). The normalized difference red-edge index, transformed chlorophyll absorption in reflectance index, and simple ratio contributed significantly to the RFR-based CTcmodel. The accuracy of AGB estimation using nonlinear methods was higher than that using the linear method. The exponential method yielded the highest accuracy(R^(2)= 0.76, RMSE = 282.8 g m, and n RMSE = 39.24%) in both the 2018 and 2019 growing seasons. The study confirms that AGB estimation models based on cumulative CTcperformed well under several irrigation treatments using high-resolution time-series UAV multispectral VIs and can support irrigation management with high spatial precision at a field scale.展开更多
Commonly used flow improvers in oilfields,such as ethylene–vinyl acetate copolymer(EVA),poly(octadecyl acrylate)(POA),and polymethylsilsesquioxane(PMSQ)are proven to be effective to enhance the flowability of crude o...Commonly used flow improvers in oilfields,such as ethylene–vinyl acetate copolymer(EVA),poly(octadecyl acrylate)(POA),and polymethylsilsesquioxane(PMSQ)are proven to be effective to enhance the flowability of crude oil.However,the addition of these flow improvers may change the stability of the emulsion and make the crude oil treatment process challenging.In this research,the impacts of different flow improvers on the interfacial properties of the emulsions containing asphaltenes are systematically investigated.The co-adsorption behaviors of the flow improvers and asphaltenes are analyzed through dynamic interfacial tension(DIFT).The rheological properties of the interfacial layer after the adsorption are explored via dilational viscoelasticity.Significant difference is observed in the structural properties of the interface adsorbed by different flow improvers,which is attributed to different interactions between the flow improvers and asphaltenes.To investigate these interactions,conductivity,asphaltenes precipitation,dynamic light scattering(DLS),and contact angle experiments are conducted systematically.Results show that EVA and POA can alter the interfacial properties by changing the asphaltene dispersion state.The interaction between EVA and asphaltenes is stronger than that between POA and asphaltenes due to the difference in molecular structures.Unlike EVA and POA,the change of interfacial property with the addition of PMSQ is attributed to the partial adsorption of asphaltenes on PMSQ.展开更多
Numerous growth and physiological variables of 3-week-old Populus simonii × P.nigra seedlings were assessed after treatment with either nitrate nitrogen(NO_(3)^(−)--N)(0.1,0.5,1,5,or 10 mmol·L^(−1)) or ammon...Numerous growth and physiological variables of 3-week-old Populus simonii × P.nigra seedlings were assessed after treatment with either nitrate nitrogen(NO_(3)^(−)--N)(0.1,0.5,1,5,or 10 mmol·L^(−1)) or ammonium nitrogen(NH_(4)^(+)+-N)(0.1,0.5,1,5,or 10 mmol·L^(−1)) to determine the best nitrogen form and concentration to optimize growth,biomass allocation,pigment content,and photosynthetic capacity.The results of combining membership function and an evaluation index suggested that,5 mmol·L^(−1) nitrogen,regardless of the form,yielded the highest comprehensive evaluation index and good growth.In addition,a Pearson correlation analysis and network visualization revealed that the total mass,shoot mass,root mass,leaf dry mass,plant height,leaf area,chlorophyll a and total chlorophyll had a physiological index connectivity degree≥15 for both nitrogen forms.Net photosynthetic rate,stomatal conductance,transpiration rate,maximum photochemical efficiency of PSII,total nitrogen content,ground diameter,chlorophyll b,and carotenoid were unique indices for evaluating NH_(4)^(+)+-N-based nutrition,which could provide a theoretical basis for evaluating the effects of nitrogen fertilizer on seedlings,cultivation periods,and stress tolerance in P.simonii× P.nigra.展开更多
The solution culture method was used to study the effect of increasing nitrogen on the growth and pho-tosynthesis of poplar seedlings under 100 mmol L-1 NaCl stress. I Increase in nitrogen reduced stomatal limitation ...The solution culture method was used to study the effect of increasing nitrogen on the growth and pho-tosynthesis of poplar seedlings under 100 mmol L-1 NaCl stress. I Increase in nitrogen reduced stomatal limitation of leaves under NaCl stress, improved utilization of CO2 by mesophyll cells, enhanced photosynthetic carbon assimi-lation capacity, significantly alleviated saline damage of NaCl, and promoted the accumulation of aboveground and root biomass. I Increased nitrogen enhanced photochemical efficiency (ΦPSⅡ) and electron transport rates, relieved the reduction of maximum photochemical efficiency (Fv/Fm) under NaCl, and reduced the degree of photoinhibition caused by NaCl stress. Increased nitrogen applications reduced the proportion of energy dissipating in the form of ineffective heat energy and hence a greater proportion of light energy absorbed by leaves was allocated to photo-chemical reactions. Under treatment with increased nitro-gen, the synergistic effect of heat dissipation and the xanthophyll cycle in the leaves effectively protected pho-tosynthetic PSⅡ and enhanced light energy utilization of leaves under NaCl stress. The increased nitrogen promoted photosynthetic electron supply and transport ability under NaCl stress evident in enhanced functioning of the oxygen-evolving complex on the electron donor side of PS Ⅱ. It increased the ability of the receptor pool to accept electrons on the PSII electron acceptor side and improved the sta-bility of thylakoid membranes under NaCl stress. Therefore, increasing nitrogen applications under NaCl stress can promote poplar growth by improving the effi-ciency of light energy utilization.展开更多
Electric double-layer capacitors(EDLCs) are emerging technologies to meet the ever-increasing demand for sustainable energy storage devices and systems in the 21 st Century owing to their advantages such as long lifet...Electric double-layer capacitors(EDLCs) are emerging technologies to meet the ever-increasing demand for sustainable energy storage devices and systems in the 21 st Century owing to their advantages such as long lifetime, fast charging speed and environmentally-friendly nature, which play a critical part in satisfying the demand of electronic devices and systems. Although it is generally accepted that EDLCs are suitable for working at low temperatures down to-40℃, there is a lack of comprehensive review to summarize the quantified performance of EDLCs when they are subjected to low-temperature environments. The rapid and growing demand for high-performance EDLCs for auxiliary power systems in the aeronautic and aerospace industries has triggered the urge to extend their operating temperature range,especially at temperatures below-40℃. This article presents an overview of EDLC’s performance and their challenges at extremely low temperatures including the capability of storing a considerable amount of electrical energy and maintaining long-term stability. The selection of electrolytes and electrode materials is crucial to the performance of EDLCs operating at a desired low-temperature range. Strategies to improve EDLC’s performance at extremely low temperatures are discussed, followed by the future perspectives to motivate more future studies to be conducted in this area.展开更多
This paper takes the Fujian Meteorological Service Center as the research objective, and uses the methods of departmental data sharing and network search to study the dissemination mechanism of meteorological informat...This paper takes the Fujian Meteorological Service Center as the research objective, and uses the methods of departmental data sharing and network search to study the dissemination mechanism of meteorological information in the whole media era. The result shows that it is of great significance to actively adapt to the characteristics of information dissemination in the all-media era, establish and improve meteorological information service rules and supervision mechanisms, actively explore strong measures to strengthen the monitoring of meteorological services, promptly release authoritative voices, curb the breeding of rumors, regulate the propagation path, and conduct meteorological information dissemination assessment. Finally, this paper proposes the construction of meteorological information dissemination mechanism from five aspects: service quality assessment, introduction of enterprise information filing and credit management system, establishment of authoritative meteorological information sharing channels, formulation of emergency response plans, and vigorous promotion of meteorological popularization. The mechanism provides a theoretical reference for the meteorological department to better adapt to the all-media context and to carry out scientific and effective media-based public opinion information risk management.展开更多
Wearable electronics has been one of the hottest research topics in recent years and fabric is regarded as a very promising substrate for the wearable units because of its excellent wearability.So far,there is no repo...Wearable electronics has been one of the hottest research topics in recent years and fabric is regarded as a very promising substrate for the wearable units because of its excellent wearability.So far,there is no report on the construction of a fabric-based optical switch.In the present work we fabricate a silk fabric-based optical switch via screen-printing of silver interdigital electrode and Bi2S3 nanowires network layer.Bi2S3 NWs with展开更多
With rapid advances of miniaturization and wireless technologies,electronics has been associated with traditional textiles to develop smart wearable devices for daily health monitoring and fitness tracking 1-2.It is o...With rapid advances of miniaturization and wireless technologies,electronics has been associated with traditional textiles to develop smart wearable devices for daily health monitoring and fitness tracking 1-2.It is of great demand to fabricate flexible materials that possess both wearability and prac-展开更多
Flexible supercapacitors have attracted much attention owing to their great potentials in wearable electronics.However,flexible solid state supercapacitor with silk fabric as the supporting substrate has not been real...Flexible supercapacitors have attracted much attention owing to their great potentials in wearable electronics.However,flexible solid state supercapacitor with silk fabric as the supporting substrate has not been realized.In this work,a simple and low-cost method is introduced to fabricate flexible solid-state supercapacitors on silk fabric via展开更多
Developing new types of rechargeable metal-ion batteries beyond lithium-ions,including alkaline ion(such as Na+,K+)and multivalent ion(such as Mg 2+,Zn 2+,Ca 2+and Al 3+)batteries,is progressing quickly towards large-...Developing new types of rechargeable metal-ion batteries beyond lithium-ions,including alkaline ion(such as Na+,K+)and multivalent ion(such as Mg 2+,Zn 2+,Ca 2+and Al 3+)batteries,is progressing quickly towards large-scale energy storage systems.However,the major obstacle to their large-scale applications has been a lack of appropriate electrode materials with reversible metal ions insertion/extraction be-havior,resulting in inferior electrochemical performance.Here we develop a well-designed MoS_(2)/MoO_(2) hybrid nanosheets anchored on carbon cloth(MoS_(2)/MoO_(2)/CC)as electrode materials.This rational de-sign can effectively shorten ion diffusion distance,increase electric conductivity of the electrode,and buffer volume change.Benefiting from the synergistic effect of structural and compositional features,the MoS_(2)/MoO_(2)/CC electrode exhibits high initial reversible capacities(326 mA h g^(−1) at 0.1 A g^(−1) in magnesium-ion storage;1270 mA h g^(−1) at 0.1 A g^(−1) in sodium-ion storage),excellent rate capacities(57 mA h g^(−1) at 10 A g^(−1) in magnesium-ion storage;335 mA h g^(−1) at 5 A g^(−1) in sodium-ion storage)and long-term cycling stability(105 mA h g^(−1) after 600 cycle at 1 A g^(−1) in magnesium-ion storage;208 mA h g^(−1) after 600 cycles at 5 A g^(−1) in sodium-ion storage).We expect that the multi-engineering strategy will provide some valuable insights for the development of other advanced electrode materials for high-performance metal-ion batteries.展开更多
基金National Natural Science Foundation of China(No.21876070)for their support of this study.
文摘A synergistic system of water falling film dielectric barrier discharge(DBD)plasma and persulfate(PS)was set up and used for oxidizing ciprofloxacin(CIP)in water.Results of reactive species formation in the DBD-only system as well as the DBD–PS system verified the PS activation in the DBD system.Influencing factors on CIP degradation and the degradation process were also been studied.The obtained results showed that the presence of PS could greatly improve the degradation and mineralization of CIP and that the degradation efficiency could reach 97.73%after only 40 min treatment with 4 m M PS addition.The increase of PS concentration,the lower CIP concentration,the acidic solution p H and the addition of metal ions(Fe^(2+)and Cu^(2+))enhanced the CIP degradation,while the existence of Cl^(-)and HCO_(3)^(-)had a negative effect.The experiments related to scavenger addition confirmed the contribution of the main reactive species to the CIP oxidation.Three probable degradation pathways were proposed by analyzing the inorganic ions and organic byproducts formed during the CIP degradation.The toxicity evaluation results of the CIP and its intermediates confirmed the effectiveness of the DBD–PS synergistic system.
基金supported by the National Natural Science Foundation of China(No.31500323)
文摘We applied under pot-culture conditions and the double-casing pot method to study the characteristics of photosynthetic gas exchange and chlorophyll fluorescence in the leaves of Physocarpus amurensis Maxim(PA) and Physocarpus opulifolius under flooding stress.Our results indicate a significantly higher flooding tolerance of P.opulifolius compared to P.amurensis.Especially in P.amurensis, the limitation of non-stomatal factors played a major role in the advanced stages of flooding stress,observed as a rapid increase of the intercellular CO_2 concentration(C_i) and a decrease of the stomatal limitation value(L_s).The maximal PSII photochemical efficiencies(F_v/F_m) and actual photochemical efficiency(?_(PSII)) in the leaves of P.opulifolius were significantly higher, and the extent of decrease during the flooding process was smaller than in P.amurensis.In addition, the non-chemical quenching(NPQ) in the leaves of P.opulifolius significantly increased from the 10 th day under flooding stress,while the variation of NPQ in the leaves of P.amurensis was much smaller.This indicates that the leaves of P.opulifolius had not only higher PSII photochemical activity, but also improved tolerance to flooding stress, which may be caused by its ability to dissipate excess excitation energy by starting NPQ.At the 16 th day under flooding stress, the PIABSsignificantly decreased with greater extent of decrease than F_v/F_m in the leaves of both Physocarpus,but the decreasing extent of PIABSin P.opulifolius was significantly smaller than in P.amurensis.In the 16 th day under flooding stress, the fluorescence at J and I point(V_J and V_I) in P.amurensis were significantly higher, and the extent of increase in V_J was greater than V_I.However, the variations of V_Jand V_I in the leaves of P.opulifolius were smaller, suggesting that the damage sites of flooding stress to PSII in the leaves of P.amurensis were mainly located in the electron transport process from Q_A at the PSII receptor side to Q_B.Flooding stress reduced the proportion(φ Eo) of luminous energy absorbed by the PSII reaction center for the electron transport following Q_A^-, while the maximum quantum yield(φ Do) of non-photochemical quenching increased.However, the TR_o/RC and ETo/RC in the leaves of P.amurensis decreased accompanied by a dramatic increase of energy(DI_o/RC) from the dissipation in the reaction center.This further indicated that the function of the PSII reaction center in the leaves of P.amurensis was significantly lower than in P.opulifolius.
基金financially supported by the National Natural Science Foundation(31500323 41501583 31370426)
文摘This study investigates the effects of cold-acclimation in conferring chilling tolerance in seedlings of the mulberry(Morus alba) variety ‘Qiuyu’. Changes in photosynthesis and antioxidant enzymes in chilling acclimatized(CA), and non-acclimatized(NA) seedlings were recorded during chilling stress(3 °C) and a recovery period(25 °C) each for 3 days. The results showed that CA plants had higher net photosynthetic rates(P_n), stomatal conductance(G_s), and maximum photochemical efficiency of photosystem Ⅱ(F_v/F_m) in response to chilling stress compared to NA. The seedlings maintained the same trends during the recovery stage. The responses of Q_A reduction degree (1-q_P) and prime electronic transfer rates(F_o) were lower in acclimatized than in non-acclimatized seedlings. Low-temperature acclimation and chilling stress also caused an increase in leaf proline and soluble sugar contents. Leaf malondialdehyde levels were significantly lower while ascorbate peroxidase(APX) activity was significantly higher in acclimatized seedlings, suggesting that elevated osmolytes and APX confer resistance to chilling temperatures. In this study on the response of mulberry seedlings to chilling stress, we also looked at the recovery process. The response to chilling determines whether mulberry leaves can survive under cold temperatures, while the recovery process determines whether photosynthesis can recover as soon as possible to avoid any secondary damage.
基金the Heilongjiang Province Science Foundation for Youths(Grant No.QC2016018)the National Natural Science Foundation of China(Grant No.31600508)+2 种基金the Fundamental Research Funds for the Central University(2572017CA21)the Application Technology Research and Development Projects of Heilongjiang Province(Grant No.WB13B104)the Science and Technology Project of Heilongjiang Farms&Land Reclamation Administration(Grant No.HNK135-01-056)。
文摘Intercropping of mulberry(Morus alba L.)and alfalfa(Medicago sativa L.)is a new forestry-grass compound model in China,which can provide high forage yields with high protein.Nitrogen application is one of the important factors determining the production and quality of this system.To elucidate the advantages of intercropping and nitrogen application,we analyzed the changes of physicochemical properties,enzyme activities,and microbial communities in the rhizosphere soil.We used principal components analysis(PCA)and redundancy discriminators analysis to clarify the relationships among treatments and between treatments and environmental factors,respectively.The results showed that nitrogen application significantly increased pH value,available nitrogen content,soil water content(SWC),and urea(URE)activity in rhizosphere soil of monoculture mulberry.In contrast,intercropping and intercropping+N significantly decreased pH and SWC in mulberry treatments.Nitrogen,intercropping and intercropping+N sharply reduced soil organic matter content and SWC in alfalfa treatments.Nitrogen,intercropping,and intercropping+N increased the values of McIntosh diversity(U),Simpson diversity(D),and Shannon-Weaver diversity(H’)in mulberry treatments.However,PC A scatter plots showed clustering of monoculture mulberry with nitrogen(MNE)and intercropping mulberry without nitrogen(M0).Intercropping reduced both H’and D but nitrogen application showed no effect on diversity of microbial communities in alfalfa.There were obvious differences in using the six types of carbon sources between mulberry and alfalfa treatments.Nitrogen and intercropping increased the numbers of sole carbon substrate in mulberry treatments where the relative use rate exceeded 4%.While the numbers declined in alfalfa with nitrogen and intercropping.RDA indicated that URE was positive when intercropping mulberry was treated with nitrogen,but was negative in monoculture alfalfa treated with nitrogen.Soil pH and SWC were positive with mulberry treatments but were negative with alfalfa treatments.Intercropping with alfalfa benefited mulberry in the absence of nitrogen application.Intercropping with alfalfa and nitrogen application could improve the microbial community function and diversity in rhizosphere soil of mulberry.The microbial community in rhizosphere soil of mulberry and alfalfa is strategically complementary in terms of using carbon sources.
基金sponsored by the National Key Research and Development Program of China(2016YFA0201700,2016YFA0201702)the Fundamental Research Funds for the Central Universities(2232019A3-06,2232019D3-02)+2 种基金the National Key Research and Development Program of China(2018YFC1105800)the National Natural Science Foundation of China(21674018,51903045)the Shanghai Belt and Road Joint Laboratory of Advanced Fiber and Low-Dimension Materials(18520750400).
文摘Fluorescent silk is fundamentally important for the development of future tissue engineering scaffolds.Despite great progress in the preparation of a variety of colored silks,fluorescent silk with enhanced mechanical properties has yet to be explored.In this study,we report on the fabrication of intrinsically super-strong fluorescent silk by feeding Bombyx mori silkworm carbon nanodots(CNDs).The CNDs were incorporated into silk fibroin,hindering the conformation transformation,confining crystallization,and inducing orientation of mesophase.The resultant silk exhibited super-strong mechanical properties with breaking strength of 521.9±82.7 MPa and breaking elongation of 19.2±4.3%,improvements of 55.1%and 53.6%,respectively,in comparison with regular silk.The CNDs-reinforced silk displayed intrinsic blue fluorescence when exposed to 405 nm laser and exhibited no cytotoxic effect on cells,suggesting that multi-functional silks would be potentially useful in bioimaging and other applications.
基金funded by the National Natural Science Foundation of China (51979233)the Natural Science Basic Research Plan in Shaanxi Province of China (2022JQ-363)。
文摘Estimating spatial variation in crop transpiration coefficients(CTc) and aboveground biomass(AGB)rapidly and accurately by remote sensing can facilitate precision irrigation management in semiarid regions. This study developed and assessed a novel machine learning(ML) method for estimating CTc and AGB using time-series unmanned aerial vehicle(UAV)-based multispectral vegetation indices(VIs)of maize under several irrigation treatments at the field scale. Four ML regression methods: multiple linear regression(MLR), support vector regression(SVR), random forest regression(RFR), and adaptive boosting regression(ABR), were used to address the complex relationship between CTcand VIs. AGB was then estimated using exponential, logistic, sigmoid, and linear equations because of their clear mathematical formulations based on the optimal CTcestimation model. The UAV VIs-derived CTcusing the RFR estimation model yielded the highest accuracy(R^(2)= 0.91, RMSE = 0.0526, and n RMSE = 9.07%). The normalized difference red-edge index, transformed chlorophyll absorption in reflectance index, and simple ratio contributed significantly to the RFR-based CTcmodel. The accuracy of AGB estimation using nonlinear methods was higher than that using the linear method. The exponential method yielded the highest accuracy(R^(2)= 0.76, RMSE = 282.8 g m, and n RMSE = 39.24%) in both the 2018 and 2019 growing seasons. The study confirms that AGB estimation models based on cumulative CTcperformed well under several irrigation treatments using high-resolution time-series UAV multispectral VIs and can support irrigation management with high spatial precision at a field scale.
基金supported by the National Natural Science Foundation of China(51704315)。
文摘Commonly used flow improvers in oilfields,such as ethylene–vinyl acetate copolymer(EVA),poly(octadecyl acrylate)(POA),and polymethylsilsesquioxane(PMSQ)are proven to be effective to enhance the flowability of crude oil.However,the addition of these flow improvers may change the stability of the emulsion and make the crude oil treatment process challenging.In this research,the impacts of different flow improvers on the interfacial properties of the emulsions containing asphaltenes are systematically investigated.The co-adsorption behaviors of the flow improvers and asphaltenes are analyzed through dynamic interfacial tension(DIFT).The rheological properties of the interfacial layer after the adsorption are explored via dilational viscoelasticity.Significant difference is observed in the structural properties of the interface adsorbed by different flow improvers,which is attributed to different interactions between the flow improvers and asphaltenes.To investigate these interactions,conductivity,asphaltenes precipitation,dynamic light scattering(DLS),and contact angle experiments are conducted systematically.Results show that EVA and POA can alter the interfacial properties by changing the asphaltene dispersion state.The interaction between EVA and asphaltenes is stronger than that between POA and asphaltenes due to the difference in molecular structures.Unlike EVA and POA,the change of interfacial property with the addition of PMSQ is attributed to the partial adsorption of asphaltenes on PMSQ.
基金This work was supported by the Science Fund Project of Heilongjiang Province of China(ZD2020C004)the Special Fund for Basic Scientifi c research operation Fee of Central University(2572019CT02)+1 种基金the Innovation Project of State Key Laboratory of Tree Genetics and Breeding(Northeast Forestry University)(2019A03)Heilongjiang Touyan Innovation Team Program(Tree Genetics and Breeding Innovation Team).
文摘Numerous growth and physiological variables of 3-week-old Populus simonii × P.nigra seedlings were assessed after treatment with either nitrate nitrogen(NO_(3)^(−)--N)(0.1,0.5,1,5,or 10 mmol·L^(−1)) or ammonium nitrogen(NH_(4)^(+)+-N)(0.1,0.5,1,5,or 10 mmol·L^(−1)) to determine the best nitrogen form and concentration to optimize growth,biomass allocation,pigment content,and photosynthetic capacity.The results of combining membership function and an evaluation index suggested that,5 mmol·L^(−1) nitrogen,regardless of the form,yielded the highest comprehensive evaluation index and good growth.In addition,a Pearson correlation analysis and network visualization revealed that the total mass,shoot mass,root mass,leaf dry mass,plant height,leaf area,chlorophyll a and total chlorophyll had a physiological index connectivity degree≥15 for both nitrogen forms.Net photosynthetic rate,stomatal conductance,transpiration rate,maximum photochemical efficiency of PSII,total nitrogen content,ground diameter,chlorophyll b,and carotenoid were unique indices for evaluating NH_(4)^(+)+-N-based nutrition,which could provide a theoretical basis for evaluating the effects of nitrogen fertilizer on seedlings,cultivation periods,and stress tolerance in P.simonii× P.nigra.
基金supported by the Fundamental Research Funds for the Central Universities(2572018BE05)the National Natural Science Foundation of China(3150032331370426)
文摘The solution culture method was used to study the effect of increasing nitrogen on the growth and pho-tosynthesis of poplar seedlings under 100 mmol L-1 NaCl stress. I Increase in nitrogen reduced stomatal limitation of leaves under NaCl stress, improved utilization of CO2 by mesophyll cells, enhanced photosynthetic carbon assimi-lation capacity, significantly alleviated saline damage of NaCl, and promoted the accumulation of aboveground and root biomass. I Increased nitrogen enhanced photochemical efficiency (ΦPSⅡ) and electron transport rates, relieved the reduction of maximum photochemical efficiency (Fv/Fm) under NaCl, and reduced the degree of photoinhibition caused by NaCl stress. Increased nitrogen applications reduced the proportion of energy dissipating in the form of ineffective heat energy and hence a greater proportion of light energy absorbed by leaves was allocated to photo-chemical reactions. Under treatment with increased nitro-gen, the synergistic effect of heat dissipation and the xanthophyll cycle in the leaves effectively protected pho-tosynthetic PSⅡ and enhanced light energy utilization of leaves under NaCl stress. The increased nitrogen promoted photosynthetic electron supply and transport ability under NaCl stress evident in enhanced functioning of the oxygen-evolving complex on the electron donor side of PS Ⅱ. It increased the ability of the receptor pool to accept electrons on the PSII electron acceptor side and improved the sta-bility of thylakoid membranes under NaCl stress. Therefore, increasing nitrogen applications under NaCl stress can promote poplar growth by improving the effi-ciency of light energy utilization.
基金the Australian Research Council for its support through the Discovery Project scheme (DP190103186)the Industrial Transformation Training Centre Scheme(IC180100005)。
文摘Electric double-layer capacitors(EDLCs) are emerging technologies to meet the ever-increasing demand for sustainable energy storage devices and systems in the 21 st Century owing to their advantages such as long lifetime, fast charging speed and environmentally-friendly nature, which play a critical part in satisfying the demand of electronic devices and systems. Although it is generally accepted that EDLCs are suitable for working at low temperatures down to-40℃, there is a lack of comprehensive review to summarize the quantified performance of EDLCs when they are subjected to low-temperature environments. The rapid and growing demand for high-performance EDLCs for auxiliary power systems in the aeronautic and aerospace industries has triggered the urge to extend their operating temperature range,especially at temperatures below-40℃. This article presents an overview of EDLC’s performance and their challenges at extremely low temperatures including the capability of storing a considerable amount of electrical energy and maintaining long-term stability. The selection of electrolytes and electrode materials is crucial to the performance of EDLCs operating at a desired low-temperature range. Strategies to improve EDLC’s performance at extremely low temperatures are discussed, followed by the future perspectives to motivate more future studies to be conducted in this area.
文摘This paper takes the Fujian Meteorological Service Center as the research objective, and uses the methods of departmental data sharing and network search to study the dissemination mechanism of meteorological information in the whole media era. The result shows that it is of great significance to actively adapt to the characteristics of information dissemination in the all-media era, establish and improve meteorological information service rules and supervision mechanisms, actively explore strong measures to strengthen the monitoring of meteorological services, promptly release authoritative voices, curb the breeding of rumors, regulate the propagation path, and conduct meteorological information dissemination assessment. Finally, this paper proposes the construction of meteorological information dissemination mechanism from five aspects: service quality assessment, introduction of enterprise information filing and credit management system, establishment of authoritative meteorological information sharing channels, formulation of emergency response plans, and vigorous promotion of meteorological popularization. The mechanism provides a theoretical reference for the meteorological department to better adapt to the all-media context and to carry out scientific and effective media-based public opinion information risk management.
文摘Wearable electronics has been one of the hottest research topics in recent years and fabric is regarded as a very promising substrate for the wearable units because of its excellent wearability.So far,there is no report on the construction of a fabric-based optical switch.In the present work we fabricate a silk fabric-based optical switch via screen-printing of silver interdigital electrode and Bi2S3 nanowires network layer.Bi2S3 NWs with
基金Natural Science Foundation of China,Specialized Research Fund for the Doctoral Program of Higher Education(RFDP)Chongqing Natural Science Foundation and Young Core Teacher Program of the Municipal Higher Educational Institution of Chongqing
文摘With rapid advances of miniaturization and wireless technologies,electronics has been associated with traditional textiles to develop smart wearable devices for daily health monitoring and fitness tracking 1-2.It is of great demand to fabricate flexible materials that possess both wearability and prac-
文摘Flexible supercapacitors have attracted much attention owing to their great potentials in wearable electronics.However,flexible solid state supercapacitor with silk fabric as the supporting substrate has not been realized.In this work,a simple and low-cost method is introduced to fabricate flexible solid-state supercapacitors on silk fabric via
基金financially supported by in part the National Science Fund for Distinguished Young Scholars (No.51625102)the National Natural Science Foundation of China (Nos.51971065,22075173)+1 种基金the Innovation Program of Shanghai Municipal Educa-tion Commission (No.2019-01-07-00-07-E00028)the Science and Science and Technology Commission of Shanghai Municipality (Nos.19DZ2271100 and 21010501100).
文摘Developing new types of rechargeable metal-ion batteries beyond lithium-ions,including alkaline ion(such as Na+,K+)and multivalent ion(such as Mg 2+,Zn 2+,Ca 2+and Al 3+)batteries,is progressing quickly towards large-scale energy storage systems.However,the major obstacle to their large-scale applications has been a lack of appropriate electrode materials with reversible metal ions insertion/extraction be-havior,resulting in inferior electrochemical performance.Here we develop a well-designed MoS_(2)/MoO_(2) hybrid nanosheets anchored on carbon cloth(MoS_(2)/MoO_(2)/CC)as electrode materials.This rational de-sign can effectively shorten ion diffusion distance,increase electric conductivity of the electrode,and buffer volume change.Benefiting from the synergistic effect of structural and compositional features,the MoS_(2)/MoO_(2)/CC electrode exhibits high initial reversible capacities(326 mA h g^(−1) at 0.1 A g^(−1) in magnesium-ion storage;1270 mA h g^(−1) at 0.1 A g^(−1) in sodium-ion storage),excellent rate capacities(57 mA h g^(−1) at 10 A g^(−1) in magnesium-ion storage;335 mA h g^(−1) at 5 A g^(−1) in sodium-ion storage)and long-term cycling stability(105 mA h g^(−1) after 600 cycle at 1 A g^(−1) in magnesium-ion storage;208 mA h g^(−1) after 600 cycles at 5 A g^(−1) in sodium-ion storage).We expect that the multi-engineering strategy will provide some valuable insights for the development of other advanced electrode materials for high-performance metal-ion batteries.
