Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S...Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S_(4) heterostructures with strong hetero-interface interaction and abundant contact were constructed via an impregnation-annealing strategy.Efficient charge transfer from ZnIn_(2)S_(4) to WSe_(2)was evidenced by transient absorption spectroscopy in crafted heterostructures owing to the tight and2D face-to-face contact.As a result,the prepared WSe_(2)/ZnIn_(2)S_(4) heterostructures exhibited boosted photocatalytic performance and a highest hydrogen evolution rate of 3.377 mmol/(g h)was achieved with an apparent quantum yield of 45.7%at 420 nm.The work not only provides new strategies to achieve efficient 2D/2D heterostructures but also paves the way for the development of green hydrogen in the future.展开更多
A simple technique is proposed for highly-efficient plane processing fully based on femtosecond laser beam shaping. The laser intensity distribution is transformed from a Gaussian to a donut shape. As the donut-shaped...A simple technique is proposed for highly-efficient plane processing fully based on femtosecond laser beam shaping. The laser intensity distribution is transformed from a Gaussian to a donut shape. As the donut-shaped focus seems like a flat top from the side view, a plane with a high level of flatness is obtained directly by scanning once. By applying it to polishing experiments, the surface roughness can be improved significantly. The influence of scanning speed, laser pulse energy, and scanning times on the roughness is also discussed. Moreover, the scanning width can be flexibly controlled in a wide range.展开更多
[Objective]The aim was to research effects of N fertilizer reduction and application of N fertilizer(as base fertilizer)on rapeseed yield and N absorption.[Method]Based on Ganyouza No.5,the ratio of N,P2O5 andK2O was ...[Objective]The aim was to research effects of N fertilizer reduction and application of N fertilizer(as base fertilizer)on rapeseed yield and N absorption.[Method]Based on Ganyouza No.5,the ratio of N,P2O5 andK2O was set at 1:0.5:0.5;N fertilizers were set involving reduced quantity at 150 kg/hm2 and preferred quantity at 180 kg/hm2;100%,80%and 60%of N fertilizers were applied as base fertilizers in the test respectively.In general,field tests were conducted to explore effects of reduced N fertilizer and application of N fertilizer as base fertilizer on rapeseed yield and N absorption.[Resalt]When applied N fertilizer as base fertilizer was the same,plant height,stem diameter,length of major inflorescence,number of effective branch,pod number per plant,seed number per pod,and biomass yield in group with preferred N quantity were significantly higher than those in group with reduced N fertilizer.Rapeseed yield and profits in group with preferred N quantity were signifi-cantly higher than those in group with reduced N fertilizer in field with moderate fertili-ty.In fields with higher fertility,however,the two factors were just a little higher.In group with reduced N fertilizer,use efficiency of N fertilizer,N uptake efficiency,par-tial factor productivity and harvest index of N were all significantly higher than those in group with preferred N fertilizer.Agronomic nitrogen use efficiency in group with preferred N fertilizer was significantly higher than that in group with reduced N fertiliz-er in field with moderate fertility and was significantly lower in field with high yield.With amounts of N,P and K fertilizers fixed,economic characters,yield constitution,yield,profits and N absorption in group,where 60%of N fertilizers were applied as base fertilizer,were significantly higher than those in groups with 80%or 100%of base fertilizer(N fertilizers).These indicated that rational fertilization would maintain rapeseed yield high and reduce N input to improve use efficiency of N fertilizer.On the other hand,it is effective to improve rapeseed yield.'to reduce N fertilizer to 150 kg/hm2,and application of 60%.of N fertilizers as base fertilizer is still proved optimal at present.[Conclusion]The research provides.theoretioal and technical references for improvement of yield of rapeseed and efficiency of N fertilizer.展开更多
The Lower Cambrian Longwangmiao dolomite gas reservoirs in the Sichuan Basin are characterized by well-developed natural micro-fractures and dissolved pores and cavities.Due to the strong heterogeneity of reservoirs a...The Lower Cambrian Longwangmiao dolomite gas reservoirs in the Sichuan Basin are characterized by well-developed natural micro-fractures and dissolved pores and cavities.Due to the strong heterogeneity of reservoirs and the serious damage of drilling and completion fluids,acid placement is difficult,and especially the acidizing stimulation of long-interval highly deviated wells or horizontal wells is more difficult.In this paper,the diverting mechanism and rheological behavior of viscoelastic surfactant(VES)based diverting acid was firstly investigated,and the diverting acid with good diversion performance and low secondary damage was selected as the main acid.Then,based on the experimental results of its rheological behaviors,an empirical model of effective viscosity was fitted and a two-scale wormhole propagation model was coupled.And accordingly,a mathematical model for the acidizing of self-diverting acid was established to simulate the pH value,Ca^(2+)concentration,effective viscosity and wormhole shape under the effect of diverting acid in long-interval highly deviated wells that are non-uniformly damaged.Finally,gelled acid and 5%VES diverting acid were compared in terms of their etched wormhole shapes,flow rate dis-tribution and acid imbibition profiles.It is shown that the diverting acid can obviously improve the acid imbibition profile of strong-heterogeneity reservoirs to intensify low-permeability reservoir stimulation.In view of the strong heterogeneity of Longwangmiao dolomite reservoirs and the complexities of drilling and completion fluid damage in the Sichuan Basin,a placement technology was developed for variable VES concentration diverting acid in horizontal wells and long-interval highly deviated wells completed with slotted liners.This acid placement technology has been practically applied in 8 wells and their cumulative gas production rate tested at the wellhead is 1233.46×10^(4)m^(3)/d.The average production stimulation ratio per well is up to 1.95.It provides a support for the efficient development of the Longwangmiao giant gas reservoir.展开更多
基金financially supported by the National Natural Science Foundation of China (No.52106259)the Fundamental Research Funds for the Central Universities (2024MS013)Key Research and Development Program of Shaanxi (Program No.2022LL-JB-08)。
文摘Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S_(4) heterostructures with strong hetero-interface interaction and abundant contact were constructed via an impregnation-annealing strategy.Efficient charge transfer from ZnIn_(2)S_(4) to WSe_(2)was evidenced by transient absorption spectroscopy in crafted heterostructures owing to the tight and2D face-to-face contact.As a result,the prepared WSe_(2)/ZnIn_(2)S_(4) heterostructures exhibited boosted photocatalytic performance and a highest hydrogen evolution rate of 3.377 mmol/(g h)was achieved with an apparent quantum yield of 45.7%at 420 nm.The work not only provides new strategies to achieve efficient 2D/2D heterostructures but also paves the way for the development of green hydrogen in the future.
基金supported by the National Key R&D Program of China(No.2017YFB1104300)the National Natural Science Foundation of China(NSFC)(No.51505505)+2 种基金the Hunan Provincial Innovation Foundation for Postgraduate(No.CX2015B044)the Natural Science Foundation of Hunan Province(No.2016JJ3147)the Open Research Fund of Key Laboratory of High Performance and Complex Manufacturing,Central South University(No.KFKT2015-09)
文摘A simple technique is proposed for highly-efficient plane processing fully based on femtosecond laser beam shaping. The laser intensity distribution is transformed from a Gaussian to a donut shape. As the donut-shaped focus seems like a flat top from the side view, a plane with a high level of flatness is obtained directly by scanning once. By applying it to polishing experiments, the surface roughness can be improved significantly. The influence of scanning speed, laser pulse energy, and scanning times on the roughness is also discussed. Moreover, the scanning width can be flexibly controlled in a wide range.
基金Supported by China Modern Agriculture Research System(CARS-13)Jiangxi Technological Innovation Team(20115BCB29020)Innovation Funds of Jiangxi Academy of Agricultural Sciences(2011CJJ012)
文摘[Objective]The aim was to research effects of N fertilizer reduction and application of N fertilizer(as base fertilizer)on rapeseed yield and N absorption.[Method]Based on Ganyouza No.5,the ratio of N,P2O5 andK2O was set at 1:0.5:0.5;N fertilizers were set involving reduced quantity at 150 kg/hm2 and preferred quantity at 180 kg/hm2;100%,80%and 60%of N fertilizers were applied as base fertilizers in the test respectively.In general,field tests were conducted to explore effects of reduced N fertilizer and application of N fertilizer as base fertilizer on rapeseed yield and N absorption.[Resalt]When applied N fertilizer as base fertilizer was the same,plant height,stem diameter,length of major inflorescence,number of effective branch,pod number per plant,seed number per pod,and biomass yield in group with preferred N quantity were significantly higher than those in group with reduced N fertilizer.Rapeseed yield and profits in group with preferred N quantity were signifi-cantly higher than those in group with reduced N fertilizer in field with moderate fertili-ty.In fields with higher fertility,however,the two factors were just a little higher.In group with reduced N fertilizer,use efficiency of N fertilizer,N uptake efficiency,par-tial factor productivity and harvest index of N were all significantly higher than those in group with preferred N fertilizer.Agronomic nitrogen use efficiency in group with preferred N fertilizer was significantly higher than that in group with reduced N fertiliz-er in field with moderate fertility and was significantly lower in field with high yield.With amounts of N,P and K fertilizers fixed,economic characters,yield constitution,yield,profits and N absorption in group,where 60%of N fertilizers were applied as base fertilizer,were significantly higher than those in groups with 80%or 100%of base fertilizer(N fertilizers).These indicated that rational fertilization would maintain rapeseed yield high and reduce N input to improve use efficiency of N fertilizer.On the other hand,it is effective to improve rapeseed yield.'to reduce N fertilizer to 150 kg/hm2,and application of 60%.of N fertilizers as base fertilizer is still proved optimal at present.[Conclusion]The research provides.theoretioal and technical references for improvement of yield of rapeseed and efficiency of N fertilizer.
基金Project supported by the National Science and Technology Major Project“Large-scale Oil and Gas Fields and CBM Development:Demonstration Project of Large-scale Carbonate Gas Fields in Sichuan Basin”(Code:2016ZX05052)CNPC Major Science and Technology Project“Research and Application of Deep-Temperature and High-Pressure Sulfur Gas Reservoir Reformation Technology in Sichuan Basin”(Code:2016E-0609).
文摘The Lower Cambrian Longwangmiao dolomite gas reservoirs in the Sichuan Basin are characterized by well-developed natural micro-fractures and dissolved pores and cavities.Due to the strong heterogeneity of reservoirs and the serious damage of drilling and completion fluids,acid placement is difficult,and especially the acidizing stimulation of long-interval highly deviated wells or horizontal wells is more difficult.In this paper,the diverting mechanism and rheological behavior of viscoelastic surfactant(VES)based diverting acid was firstly investigated,and the diverting acid with good diversion performance and low secondary damage was selected as the main acid.Then,based on the experimental results of its rheological behaviors,an empirical model of effective viscosity was fitted and a two-scale wormhole propagation model was coupled.And accordingly,a mathematical model for the acidizing of self-diverting acid was established to simulate the pH value,Ca^(2+)concentration,effective viscosity and wormhole shape under the effect of diverting acid in long-interval highly deviated wells that are non-uniformly damaged.Finally,gelled acid and 5%VES diverting acid were compared in terms of their etched wormhole shapes,flow rate dis-tribution and acid imbibition profiles.It is shown that the diverting acid can obviously improve the acid imbibition profile of strong-heterogeneity reservoirs to intensify low-permeability reservoir stimulation.In view of the strong heterogeneity of Longwangmiao dolomite reservoirs and the complexities of drilling and completion fluid damage in the Sichuan Basin,a placement technology was developed for variable VES concentration diverting acid in horizontal wells and long-interval highly deviated wells completed with slotted liners.This acid placement technology has been practically applied in 8 wells and their cumulative gas production rate tested at the wellhead is 1233.46×10^(4)m^(3)/d.The average production stimulation ratio per well is up to 1.95.It provides a support for the efficient development of the Longwangmiao giant gas reservoir.
