The development of an efficient catalyst for formic acid electrocatalytic oxidation reaction(FAEOR)is of great significance to accelerate the commercial application of direct formic acid fuel cells(DFAFC).Herein,palla...The development of an efficient catalyst for formic acid electrocatalytic oxidation reaction(FAEOR)is of great significance to accelerate the commercial application of direct formic acid fuel cells(DFAFC).Herein,palladium phosphide(PdxPy)porous nanotubes(PNTs)with different phosphide content(i.e.,Pd3P and Pd5P2)are prepared by combining the self-template reduction method of dimethylglyoxime-Pd(II)complex nanorods and succedent phosphating treatment.During the reduction process,the self-removal of the template and the continual inside-outside Ostwald ripening phenomenon are responsible for the generation of the one-dimensional hollow and porous architecture.On the basis of the unique synthetic procedure and structural advantages,Pd3P PNTs with optimized phos phide content show outstanding electroactivity and stability for FAEOR.Im portantly,the strong electronic effect between Pd and P promotes the direct pathway of FAEOR and inhibits the occurrence of the formic acid decomposition reaction,which effectively enhances the FAEOR electroactivity of Pd3P PNTs.In view of the facial synthesis,excellent electroactivity,high stability,and unordinary selectivity,Pd3P PNTs have the potential to be an efficient anode electrocatalyst for DFAFC.展开更多
Text summarization is an important task in natural language processing and it has been applied in many applications.Recently,abstractive summarization has attracted many attentions.However,the traditional evaluation m...Text summarization is an important task in natural language processing and it has been applied in many applications.Recently,abstractive summarization has attracted many attentions.However,the traditional evaluation metrics that consider little semantic information,are unsuitable for evaluating the quality of deep learning based abstractive summarization models,since these models may generate new words that do not exist in the original text.Moreover,the out-of-vocabulary(OOV)problem that affects the evaluation results,has not been well solved yet.To address these issues,we propose a novel model called ENMS,to enhance existing N-gram based evaluation metrics with semantics.To be specific,we present two types of methods:N-gram based Semantic Matching(NSM for short),and N-gram based Semantic Similarity(NSS for short),to improve several widely-used evaluation metrics including ROUGE(Recall-Oriented Understudy for Gisting Evaluation),BLEU(Bilingual Evaluation Understudy),etc.NSM and NSS work in different ways.The former calculates the matching degree directly,while the latter mainly improves the similarity measurement.Moreover we propose an N-gram representation mechanism to explore the vector representation of N-grams(including skip-grams).It serves as the basis of our ENMS model,in which we exploit some simple but effective integration methods to solve the OOV problem efficiently.Experimental results over the TAC AESOP dataset show that the metrics improved by our methods are well correlated with human judgements and can be used to better evaluate abstractive summarization methods.展开更多
In this paper,numerical simulation is conducted via our in-house solver,vim-FOAM-SJTU,developed on open-source software,OpenFOAM.Flow around static rigid cylinders and elastically mounted rigid cylinder constrained to...In this paper,numerical simulation is conducted via our in-house solver,vim-FOAM-SJTU,developed on open-source software,OpenFOAM.Flow around static rigid cylinders and elastically mounted rigid cylinder constrained to free stream with free end are numerically investigated.Some significant conclusions are made by analyzing the different results between cases with and without free end.The turbulence model is implemented with a shear stress transport-based(SST-based)improved delayed detached eddy simulation(IDDES)approach in the vim-FOAM-SJTU.Firstly,The paper starts with the application of the vim-FOAM-SJTU solver to flow past fixed cylinder with free end at Reynolds number 43000.The numerical results are compared with experimental data.Comparison are satisfactory which implies the validity and accuracy of the current computational fluid dynamics(CFD)solver.The flow visualization in the vicinity of free-end is discussed.Subsequently,the solver is utilized to simulate the free end effect associated with the VIM of a cylinder submerged in current.The motion responses under different inflow velocities are studied.The relationship between transverse motion frequency,in-line motion frequency is discussed.Lastly,the effect of the free end on the vortex of the wake field is analyzed by comparing the 3-D vorticity diagrams of the free end cylinder.The responses of circular cylinder with or without free end are compared.展开更多
基金supported by the National Natural Science Foundation of China(21875133 and 51873100)Natural Science Foundation of Shaanxi Province(2020JZ-23)+2 种基金the National Training Program of Innovation and Entrepreneurship for Undergraduates(S202010718130)Fundamental Research Funds for the Central Universities(GK202101005,GK202103062,and 2021CBLZ004)the 111 Project(B14041).
文摘The development of an efficient catalyst for formic acid electrocatalytic oxidation reaction(FAEOR)is of great significance to accelerate the commercial application of direct formic acid fuel cells(DFAFC).Herein,palladium phosphide(PdxPy)porous nanotubes(PNTs)with different phosphide content(i.e.,Pd3P and Pd5P2)are prepared by combining the self-template reduction method of dimethylglyoxime-Pd(II)complex nanorods and succedent phosphating treatment.During the reduction process,the self-removal of the template and the continual inside-outside Ostwald ripening phenomenon are responsible for the generation of the one-dimensional hollow and porous architecture.On the basis of the unique synthetic procedure and structural advantages,Pd3P PNTs with optimized phos phide content show outstanding electroactivity and stability for FAEOR.Im portantly,the strong electronic effect between Pd and P promotes the direct pathway of FAEOR and inhibits the occurrence of the formic acid decomposition reaction,which effectively enhances the FAEOR electroactivity of Pd3P PNTs.In view of the facial synthesis,excellent electroactivity,high stability,and unordinary selectivity,Pd3P PNTs have the potential to be an efficient anode electrocatalyst for DFAFC.
基金This work was supported by the National Natural Science Foundation of China under Grant Nos.62172149,61632009,62172159,and 62172372the Natural Science Foundation of Hunan Province of China under Grant No.2021JJ30137the Open Project of ZHEJIANG LAB under Grant No.2019KE0AB02.
文摘Text summarization is an important task in natural language processing and it has been applied in many applications.Recently,abstractive summarization has attracted many attentions.However,the traditional evaluation metrics that consider little semantic information,are unsuitable for evaluating the quality of deep learning based abstractive summarization models,since these models may generate new words that do not exist in the original text.Moreover,the out-of-vocabulary(OOV)problem that affects the evaluation results,has not been well solved yet.To address these issues,we propose a novel model called ENMS,to enhance existing N-gram based evaluation metrics with semantics.To be specific,we present two types of methods:N-gram based Semantic Matching(NSM for short),and N-gram based Semantic Similarity(NSS for short),to improve several widely-used evaluation metrics including ROUGE(Recall-Oriented Understudy for Gisting Evaluation),BLEU(Bilingual Evaluation Understudy),etc.NSM and NSS work in different ways.The former calculates the matching degree directly,while the latter mainly improves the similarity measurement.Moreover we propose an N-gram representation mechanism to explore the vector representation of N-grams(including skip-grams).It serves as the basis of our ENMS model,in which we exploit some simple but effective integration methods to solve the OOV problem efficiently.Experimental results over the TAC AESOP dataset show that the metrics improved by our methods are well correlated with human judgements and can be used to better evaluate abstractive summarization methods.
基金supported by the National Natural Science Foundation of China(Grant Nos.52131102,51909160 and 51879159)the National Key Research and Development Program of China(Grant No.2019YFB1704200).
文摘In this paper,numerical simulation is conducted via our in-house solver,vim-FOAM-SJTU,developed on open-source software,OpenFOAM.Flow around static rigid cylinders and elastically mounted rigid cylinder constrained to free stream with free end are numerically investigated.Some significant conclusions are made by analyzing the different results between cases with and without free end.The turbulence model is implemented with a shear stress transport-based(SST-based)improved delayed detached eddy simulation(IDDES)approach in the vim-FOAM-SJTU.Firstly,The paper starts with the application of the vim-FOAM-SJTU solver to flow past fixed cylinder with free end at Reynolds number 43000.The numerical results are compared with experimental data.Comparison are satisfactory which implies the validity and accuracy of the current computational fluid dynamics(CFD)solver.The flow visualization in the vicinity of free-end is discussed.Subsequently,the solver is utilized to simulate the free end effect associated with the VIM of a cylinder submerged in current.The motion responses under different inflow velocities are studied.The relationship between transverse motion frequency,in-line motion frequency is discussed.Lastly,the effect of the free end on the vortex of the wake field is analyzed by comparing the 3-D vorticity diagrams of the free end cylinder.The responses of circular cylinder with or without free end are compared.
