[2+2]-Type cyclobutane derivatives comprise a large family of natural products with diverse molecular architectures.However,the structure elucidation of the cyclobutane ring,including its connection mode and stereoche...[2+2]-Type cyclobutane derivatives comprise a large family of natural products with diverse molecular architectures.However,the structure elucidation of the cyclobutane ring,including its connection mode and stereochemistry,presents a significant challenge.Plumerubradins A-C(1-3),three novel iridoid glycoside[2+2]dimers featuring a highly functionalized cyclobutane core and multiple stereogenic centers,were isolated from the flowers of Plumeria rubra.Through biomimetic semisynthesis and chemical degradation of compounds 1-3,synthesis of phenylpropanoid-derived[2+2]dimers 7-10,combined with extensive spectroscopic analysis,single-crystal X-ray crystallography,and microcrystal electron diffraction experiments,the structures with absolute configurations of 1-3 were unequivocally elucidated.Furthermore,quantum mechanics-based^(1)H NMR iterative full spin analysis successfully established the correlations between the signal patterns of cyclobutane protons and the structural information of the cyclobutane ring in phenylpropanoid-derived[2+2]dimers,providing a diagnostic tool for the rapid structural elucidation of[2+2]-type cyclobutane derivatives.展开更多
The research on metal dimer clusters is of great importance,owing to the potential in modulating the adsorption behavior towards reaction intermediates.Here,we develop a loading heightening strategy to obtain a 32.5wt...The research on metal dimer clusters is of great importance,owing to the potential in modulating the adsorption behavior towards reaction intermediates.Here,we develop a loading heightening strategy to obtain a 32.5wt%Fe-dimer catalyst(Fe-32.5).The co-anchoring of two Fe atoms in a single triazine ring of carbon nitride with an atomic spacing of∼0.23nm is proved.Fe atoms occupy the pores of the triazine ring in the lower iron content sample(Fe-12.9 and Fe-17.1).However,with the increase of iron content to 32.5wt%,two Fe atoms simultaneously occupy one triazine ring.For Fe-32.5,besides the main peak located at∼1.5Åcorresponding to the Fe–N interaction,a peak attributed to Fe–Fe bonding is observed at∼2.2Åin Fourier-transformed k3-weithted extended X-ray absorption fine structure.Density functional theoretical calculations reveal that Fe-dimer in Fe-32.5 induces a charge redistribution compared with that in Fe-12.9 and Fe-17.1.H_(2)O^(∗)is adsorbed on O^(∗)via hydrogen bonding in Fe-12.9 and Fe-17.1.However,H_(2)O^(∗)and O^(∗)in Fe-32.5 are adsorbed on Fe–Fe dimer,resulting in a decrease in the total energy of the reaction process.For the two former,O_(2)^(-)∗adsorbs on individual Fe atoms.Fe-dimer in Fe-32.5 adsorbs O_(2)^(-)∗in the form of bridge bonds,which facilitates the·O_(2)^(-)release.Furthermore,an enhanced affinity for the substrate 3,3′,5,5′-tetramethylbenzidine and higher peroxidase-like activity were displayed.This work provides an effective mean to synthesize metal dimer clusters through high loading.展开更多
Developing machine learning frameworks with predictive power,interpretability,and transferability is crucial,yet it faces challenges in the field of electrocatalysis.To achieve this,we employed rigorous feature engine...Developing machine learning frameworks with predictive power,interpretability,and transferability is crucial,yet it faces challenges in the field of electrocatalysis.To achieve this,we employed rigorous feature engineering to establish a finely tuned gradient boosting regressor(GBR)model,which adeptly captures the physical complexity from feature space to target variables.We demonstrated that environmental electron effects and atomic number significantly govern the success of the mapping process via global and local explanations.The finely tuned GBR model exhibits exceptional robustness in predicting CO adsorption energies(R_(ave)^(2)=0.937,RMSE=0.153 eV).Moreover,the model demonstrated remarkable transfer learning ability,showing excellent predictive power for OH,NO,and N_(2) adsorption.Importantly,the GBR model exhibits exceptional predictive capability across an extensive search space,thereby demonstrating profound adaptability and versatility.Our research framework significantly enhances the interpretability and transferability of machine learning in electrocatalysis,offering vital insights for further advancements.展开更多
To enhance the comprehension of flow characteristics and enrich the well-test theory of slanted wells,this study established a well-test model for a slanted well in a heterogeneous multi-zonal reservoir.The model cons...To enhance the comprehension of flow characteristics and enrich the well-test theory of slanted wells,this study established a well-test model for a slanted well in a heterogeneous multi-zonal reservoir.The model considered closed boundaries at both the top and bottom,as well as an external boundary with infinite,closed,or constant pressure on the horizontal plane.We took the bi-zonal composite model as an example to carry out concrete analysis.Various contemporary mathematical techniques,including Laplace integral transformation,separation of variables,and eigenfunction methods,were employed to solve the model.The pressure solution in real space was obtained through Duhamel's principle and Stehfest numerical inversion,then analytical curves created,and flow stages were defined for a slanted well in a bi-zonal composite reservoir.In addition,we performed a sensitivity analysis on some parameters affecting the curves.For a tri-zonal composite model,we also plotted the well-test curves and categorized them.Finally,we validated the model through the interpretation of an example well.The results show that the fluid flow of a slanted well in a bi-zonal composite reservoir can be divided into seven main stages,including wellbore storage effect(WSE)stage,skin effect(SE)stage,linear flow(LF)stage,radial flow(RF)stage of the 1st zone,transitional flow(TF)stage from the 1st to the 2nd zone,RF stage of the 2nd zone,and the external boundary response stage.The position of the pressure curve at the SE stage and LF stage decreases as the length and inclination angle increase.Correspondingly,the pressure curve at the RF stage of the 2nd zone and external boundary response stage decreases with increasing mobility ratio.Furthermore,as the radius of the 1st zone increases,the pressure curve at the RF stage of the 1st zone and the TF stage shifts towards the right.The established model and plotted curves provide a theoretical basis for further studies on the flow behavior of slanted wells in composite reservoirs.展开更多
Platinum group alloys have an excellent electronic structure for oxidation of alcohols,but the active sites are more susceptible to deactivation by CO adsorbates(CO_(ads)).The precise integration of single-atom and al...Platinum group alloys have an excellent electronic structure for oxidation of alcohols,but the active sites are more susceptible to deactivation by CO adsorbates(CO_(ads)).The precise integration of single-atom and alloy structures is highly attractive for energy conversion but still a challenge.Here,we report an ionexchange coupled in situ reduction strategy to fabricate hollow PtPdTe alloy nanoreactors loaded with atomically dispersed Cu sites(Cu_(SA)/h-PtPdTe NRs).The planted oxyphilic Cu single sites and resulted compressive strains are conductive to modulating the electronic structure of the active sites,which changes the rate-determining step of the reaction while inhibiting the formation of CO_(ads)and modulating the adsorption of intermediates,resulting in the improved activity and stability.Specifically,the obtained Cu_(SA)/h-PtPdTe NRs exhibit an excellent oxidation performance of multiple alcohols,especially for methanol and ethanol,with 8.0 and 10.3 times of the mass activity higher than Pt/C,and the activity could be recovered by refreshing the electrolyte and could be sustained for 72,000 and 36,000 s,respectively.Meanwhile,Cu_(SA)/h-PtPdTe NRs show superior oxidation performance and durability to ethylene glycol and glycerol.This work pioneers the realization of precise modulation of catalytic sites using single atoms and provides an encouraging pathway for the design of efficient and stable electrocatalysts for the oxidation of multiple alcohols,which could broaden the range of options and sources of fuel cells.展开更多
Determining the optimal ceramic content of the ceramics-in-polymer composite electrolytes and the appropriate stack pressure can effectively improve the interfacial contact of solid-state batteries(SSBs).Based on the ...Determining the optimal ceramic content of the ceramics-in-polymer composite electrolytes and the appropriate stack pressure can effectively improve the interfacial contact of solid-state batteries(SSBs).Based on the contact mechanics model and constructed by the conjugate gradient method,continuous convolution,and fast Fourier transform,this paper analyzes and compares the interfacial contact responses involving the polymers commonly used in SSBs,which provides the original training data for machine learning.A support vector regression model is established to predict the relationship between the content of ceramics and the interfacial resistance.The Bayesian optimization and K-fold cross-validation are introduced to find the optimal combination of hyperparameters,which accelerates the training process and improves the model’s accuracy.We found the relationship between the content of ceramics,the stack pressure,and the interfacial resistance.The results can be taken as a reference for the design of the low-resistance composite electrolytes for solid-state batteries.展开更多
基金supported by the National Key R&D Program of China(No.2023YFC3503902)the National Natural Science Foundation of China(Nos.82293681(82293680)and 82321004)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(Nos.2022B1515120015 and 2021A1515111021)the Guangdong Major Project of Basic and Applied Basic Research(No.2023B0303000026)the Science and Technology Projects in Guangzhou(No.202102070001).
文摘[2+2]-Type cyclobutane derivatives comprise a large family of natural products with diverse molecular architectures.However,the structure elucidation of the cyclobutane ring,including its connection mode and stereochemistry,presents a significant challenge.Plumerubradins A-C(1-3),three novel iridoid glycoside[2+2]dimers featuring a highly functionalized cyclobutane core and multiple stereogenic centers,were isolated from the flowers of Plumeria rubra.Through biomimetic semisynthesis and chemical degradation of compounds 1-3,synthesis of phenylpropanoid-derived[2+2]dimers 7-10,combined with extensive spectroscopic analysis,single-crystal X-ray crystallography,and microcrystal electron diffraction experiments,the structures with absolute configurations of 1-3 were unequivocally elucidated.Furthermore,quantum mechanics-based^(1)H NMR iterative full spin analysis successfully established the correlations between the signal patterns of cyclobutane protons and the structural information of the cyclobutane ring in phenylpropanoid-derived[2+2]dimers,providing a diagnostic tool for the rapid structural elucidation of[2+2]-type cyclobutane derivatives.
基金financially supported by National Natural Science Foundation of China(No.52301011)Hainan Provincial Natural Science Foundation of China(No.524QN226)the Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices,Ministry of Education,Jianghan University(No.JDGD-202315).
文摘The research on metal dimer clusters is of great importance,owing to the potential in modulating the adsorption behavior towards reaction intermediates.Here,we develop a loading heightening strategy to obtain a 32.5wt%Fe-dimer catalyst(Fe-32.5).The co-anchoring of two Fe atoms in a single triazine ring of carbon nitride with an atomic spacing of∼0.23nm is proved.Fe atoms occupy the pores of the triazine ring in the lower iron content sample(Fe-12.9 and Fe-17.1).However,with the increase of iron content to 32.5wt%,two Fe atoms simultaneously occupy one triazine ring.For Fe-32.5,besides the main peak located at∼1.5Åcorresponding to the Fe–N interaction,a peak attributed to Fe–Fe bonding is observed at∼2.2Åin Fourier-transformed k3-weithted extended X-ray absorption fine structure.Density functional theoretical calculations reveal that Fe-dimer in Fe-32.5 induces a charge redistribution compared with that in Fe-12.9 and Fe-17.1.H_(2)O^(∗)is adsorbed on O^(∗)via hydrogen bonding in Fe-12.9 and Fe-17.1.However,H_(2)O^(∗)and O^(∗)in Fe-32.5 are adsorbed on Fe–Fe dimer,resulting in a decrease in the total energy of the reaction process.For the two former,O_(2)^(-)∗adsorbs on individual Fe atoms.Fe-dimer in Fe-32.5 adsorbs O_(2)^(-)∗in the form of bridge bonds,which facilitates the·O_(2)^(-)release.Furthermore,an enhanced affinity for the substrate 3,3′,5,5′-tetramethylbenzidine and higher peroxidase-like activity were displayed.This work provides an effective mean to synthesize metal dimer clusters through high loading.
基金supported by the Research Grants Council of Hong Kong(CityU 11305919 and 11308620)and NSFC/RGC Joint Research Scheme N_CityU104/19Hong Kong Research Grant Council Collaborative Research Fund:C1002-21G and C1017-22Gsupported by the Hong Kong Research Grant Council Collaborative Research Fund:C6021-19E.
文摘Developing machine learning frameworks with predictive power,interpretability,and transferability is crucial,yet it faces challenges in the field of electrocatalysis.To achieve this,we employed rigorous feature engineering to establish a finely tuned gradient boosting regressor(GBR)model,which adeptly captures the physical complexity from feature space to target variables.We demonstrated that environmental electron effects and atomic number significantly govern the success of the mapping process via global and local explanations.The finely tuned GBR model exhibits exceptional robustness in predicting CO adsorption energies(R_(ave)^(2)=0.937,RMSE=0.153 eV).Moreover,the model demonstrated remarkable transfer learning ability,showing excellent predictive power for OH,NO,and N_(2) adsorption.Importantly,the GBR model exhibits exceptional predictive capability across an extensive search space,thereby demonstrating profound adaptability and versatility.Our research framework significantly enhances the interpretability and transferability of machine learning in electrocatalysis,offering vital insights for further advancements.
文摘To enhance the comprehension of flow characteristics and enrich the well-test theory of slanted wells,this study established a well-test model for a slanted well in a heterogeneous multi-zonal reservoir.The model considered closed boundaries at both the top and bottom,as well as an external boundary with infinite,closed,or constant pressure on the horizontal plane.We took the bi-zonal composite model as an example to carry out concrete analysis.Various contemporary mathematical techniques,including Laplace integral transformation,separation of variables,and eigenfunction methods,were employed to solve the model.The pressure solution in real space was obtained through Duhamel's principle and Stehfest numerical inversion,then analytical curves created,and flow stages were defined for a slanted well in a bi-zonal composite reservoir.In addition,we performed a sensitivity analysis on some parameters affecting the curves.For a tri-zonal composite model,we also plotted the well-test curves and categorized them.Finally,we validated the model through the interpretation of an example well.The results show that the fluid flow of a slanted well in a bi-zonal composite reservoir can be divided into seven main stages,including wellbore storage effect(WSE)stage,skin effect(SE)stage,linear flow(LF)stage,radial flow(RF)stage of the 1st zone,transitional flow(TF)stage from the 1st to the 2nd zone,RF stage of the 2nd zone,and the external boundary response stage.The position of the pressure curve at the SE stage and LF stage decreases as the length and inclination angle increase.Correspondingly,the pressure curve at the RF stage of the 2nd zone and external boundary response stage decreases with increasing mobility ratio.Furthermore,as the radius of the 1st zone increases,the pressure curve at the RF stage of the 1st zone and the TF stage shifts towards the right.The established model and plotted curves provide a theoretical basis for further studies on the flow behavior of slanted wells in composite reservoirs.
基金supported by the National Natural Science Foundation of China(22102132)the Funds for Basic Scientific Research in Central Universities+2 种基金the Scientific Research Foundation of Qingdao UniversityTaishan Scholar Program(NO.tsqnz20231213)sponsored by the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(CX2024101)。
文摘Platinum group alloys have an excellent electronic structure for oxidation of alcohols,but the active sites are more susceptible to deactivation by CO adsorbates(CO_(ads)).The precise integration of single-atom and alloy structures is highly attractive for energy conversion but still a challenge.Here,we report an ionexchange coupled in situ reduction strategy to fabricate hollow PtPdTe alloy nanoreactors loaded with atomically dispersed Cu sites(Cu_(SA)/h-PtPdTe NRs).The planted oxyphilic Cu single sites and resulted compressive strains are conductive to modulating the electronic structure of the active sites,which changes the rate-determining step of the reaction while inhibiting the formation of CO_(ads)and modulating the adsorption of intermediates,resulting in the improved activity and stability.Specifically,the obtained Cu_(SA)/h-PtPdTe NRs exhibit an excellent oxidation performance of multiple alcohols,especially for methanol and ethanol,with 8.0 and 10.3 times of the mass activity higher than Pt/C,and the activity could be recovered by refreshing the electrolyte and could be sustained for 72,000 and 36,000 s,respectively.Meanwhile,Cu_(SA)/h-PtPdTe NRs show superior oxidation performance and durability to ethylene glycol and glycerol.This work pioneers the realization of precise modulation of catalytic sites using single atoms and provides an encouraging pathway for the design of efficient and stable electrocatalysts for the oxidation of multiple alcohols,which could broaden the range of options and sources of fuel cells.
基金the National Natural Science Foundation of China(12102085)the Postdoctoral Science Foundation of China(2023M730504)the Sichuan Province Regional Innovation and Cooperation Project(2024YFHZ0210).
文摘Determining the optimal ceramic content of the ceramics-in-polymer composite electrolytes and the appropriate stack pressure can effectively improve the interfacial contact of solid-state batteries(SSBs).Based on the contact mechanics model and constructed by the conjugate gradient method,continuous convolution,and fast Fourier transform,this paper analyzes and compares the interfacial contact responses involving the polymers commonly used in SSBs,which provides the original training data for machine learning.A support vector regression model is established to predict the relationship between the content of ceramics and the interfacial resistance.The Bayesian optimization and K-fold cross-validation are introduced to find the optimal combination of hyperparameters,which accelerates the training process and improves the model’s accuracy.We found the relationship between the content of ceramics,the stack pressure,and the interfacial resistance.The results can be taken as a reference for the design of the low-resistance composite electrolytes for solid-state batteries.
