利用分子动力学模拟方法研究页岩有机质孔缝内液态烷烃赋存状态。基于OPLS（Optimized Potentials for Liquid Simulation）力场模拟计算了烷烃在不同温度和压力条件下的密度,并与实验值比较,验证了该方法的有效性。在此基础上,以正庚...利用分子动力学模拟方法研究页岩有机质孔缝内液态烷烃赋存状态。基于OPLS（Optimized Potentials for Liquid Simulation）力场模拟计算了烷烃在不同温度和压力条件下的密度,并与实验值比较,验证了该方法的有效性。在此基础上,以正庚烷为例分析了油藏条件下有机质孔缝内烷烃赋存的基本特征,并探讨了缝宽、有机质成熟度、烷烃碳链长度以及同分异构体对其赋存的影响。结果表明：1烷烃在有机质孔缝内的密度分布并非均匀,而是呈现周期性的波动;2在靠近固体壁面处烷烃会形成＂类固体＂层,其密度约为游离态流体密度的1.9~2.7倍;3液态烷烃在有机质孔缝内主要发生多层吸附,每个吸附层的厚度约为0.48 nm,吸附层的数目受缝宽和流体组分影响。实例模拟分析表明,原油在有机质孔缝内以吸附态形式存在的比例为18.2%。展开更多
The influence of the thickness of a covering liquid layer and its viscosity as well as the impact velocity on energy loss during the normal impact on a flat steel wall of spherical granules with a liquid layer was stu...The influence of the thickness of a covering liquid layer and its viscosity as well as the impact velocity on energy loss during the normal impact on a flat steel wall of spherical granules with a liquid layer was studied. Free-fall experiments were performed to obtain the restitution coefficient of elastic-plastic γ- Al2O3 granules by impact on the liquid layer, using aqueous solutions of hydroxypropyl methylcellulose with different concentrations for variation of viscosity （1-300 mPa s）, In the presence of a liquid layer, increase of liquid viscosity decreases the restitution coefficient and the minimum thickness of the liquid layer at which the granule sticks to the wall. The measured restitution coefficients were compared with experiments performed without liquid layer. In contrast to the dry restitution coefficient, due to viscous losses at lower impact velocity, higher energy dissipation was obtained, A rational explanation for the effects obtained was given by results of numerically solved force and energy balances for a granule impact on a liquid layer on the wall. The model takes into account forces acting on the granule including viscous, surface tension, capillary, contact, drag, buoyancy and gravitational forces. Good agreement between simulations and experiments has been achieved.展开更多
The reduction in noble metal content for efficient oxygen evolution catalysis is a crucial aspect towards the large scale commercialisation of polymer electrolyte membrane electrolyzers.Since catalytic stability and a...The reduction in noble metal content for efficient oxygen evolution catalysis is a crucial aspect towards the large scale commercialisation of polymer electrolyte membrane electrolyzers.Since catalytic stability and activity are inversely related,long service lifetime still demands large amounts of low-abundant and expensive iridium.In this manuscript we elaborate on the concept of maximizing the utilisation of iridium for the oxygen evolution reaction.By combining different tin oxide based support materials with liquid atomic layer deposition of iridium oxide,new possibilities are opened up to grow thin layers of iridium oxide with tuneable noble metal amounts.In-situ,time-and potential-resolved dissolution experiments reveal how the stability of the substrate and the catalyst layer thickness directly affect the activity and stability of deposited iridium oxide.Based on our results,we elaborate on strategies how to obtain stable and active catalysts with maximized iridium utilisation for the oxygen evolution reaction and demonstrate how the activity and durability can be tailored correspondingly.Our results highlight the potential of utilizing thin noble metal films with earth abundant support.materials for future catalytic applications in the energy sector.展开更多
Graphene(G),as a typical two-dimensional material,is often used as an additive for liquid lubricants.However,graphene is mostly added to liquid lubricants in a one-time manner in friction;it mainly exists in the form ...Graphene(G),as a typical two-dimensional material,is often used as an additive for liquid lubricants.However,graphene is mostly added to liquid lubricants in a one-time manner in friction;it mainly exists in the form of multilayer agglomerated structures due to theπ–πstacking between graphene sheets,making it unable to fully exert the synergistic lubrication function.Herein,we propose a new macroscopic superlubric system of graphene/potassium hydroxide(G/KOH)solution;and the graphene additive involved is exfoliated in-situ from graphene/epoxy(G/EP)friction pair by friction,continuously providing freshly-peeled graphene into KOH solution and minimizing the adverse effects of graphene agglomeration.Moreover,the in-situ produced graphene additive has thinner thickness and better anti-aggregation ability,which provide more graphene to accommodate OH−,form more stacked sandwich structures of OH−/graphene/OH−between friction pairs(i.e.,equivalent to a moving pulley block with more wheels),and finally realize superlubricity.This study develops a new liquid superlubric system suitable for alkaline environments,and at the same time proposes a new way to gradually release graphene additives in situ,rather than adding them all at once,deepening the understanding to liquid superlubricity mechanism,and paving the experimental foundation for the practical application of macroscopic superlubricity.展开更多
Lithium metal batteries based on solid electrolytes are considered as promising candidates with high energy density and safety.However,the weak solid-solid contact between electrolyte and electrode can easily lead to ...Lithium metal batteries based on solid electrolytes are considered as promising candidates with high energy density and safety.However,the weak solid-solid contact between electrolyte and electrode can easily lead to interface instability and lithium ions discontinuous migration,which seriously reduces the electrochemical performance of the battery.Herein,we construct a soft gel interfacial layer to improve the stability of the solid-solid interface between electrolyte and electrode by means of polyester-based monomers and imidazole-based ionic liquids.Based on this,garnet-type Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)particles as inorganic ceramic filler were introduced in the layer to obtain composite electrolytes with high ionic conductivity(up to 1.1×10^(-3)S/cm at 25℃).As a result,the assembled lithium symmetric battery of Li|THCE-15%LLZTO|Li suggests excellent cycling stability with 700 h at 0.1 mA/cm^(2)at 50℃,and the lithium metal batteries of LFP|THCE-15%LLZTO|Li delivers high initial discharge capacity of 128.2 mA·h/g with capacity retain of 75.48%after 150 cycles at 2 C.This work paves a new route to build safe and stable lithium metal batteries with synergistic introduction of composite electrolytes between electrolyte and electrode using soft gel interfacial layer and inorganic filler.展开更多
[Objectives]To establish the quality standard of Oxyria sinensis Hemsl.[Methods]The method in Chinese Pharmacopoeia(2020 edition)was used to determine the moisture,total ash,acid-insoluble ash and alcohol-soluble extr...[Objectives]To establish the quality standard of Oxyria sinensis Hemsl.[Methods]The method in Chinese Pharmacopoeia(2020 edition)was used to determine the moisture,total ash,acid-insoluble ash and alcohol-soluble extracts of O.sinensis.The qualitative identification of medicinal materials was carried out by microscopic identification method and thin layer chromatography(TLC).The contents of hyperoside and isoquercitrin were determined by high performance liquid chromatography(HPLC).[Results]The total amount of moisture,total ash,acid-insoluble ash,alcohol-soluble extract,hyperoside and isoquercitrin of 12 batches of medicinal materials were 8.56%-11.53%,11.26%-15.48%,1.62%-2.56%,17.75%-26.09%,and 0.036%-0.42%,respectively.The microscopic features were obvious,and pores,fibers,calcium oxalate clusters,calcium oxalate square crystals,cork cells could be observed.Fluorescent spots of the same color were displayed at the positions corresponding to the hyperoside reference substance.[Conclusions]Establishing relatively complete quality standards for O.sinensis medicinal materials can provide a reference for the quality control of medicinal materials.展开更多
文摘The influence of the thickness of a covering liquid layer and its viscosity as well as the impact velocity on energy loss during the normal impact on a flat steel wall of spherical granules with a liquid layer was studied. Free-fall experiments were performed to obtain the restitution coefficient of elastic-plastic γ- Al2O3 granules by impact on the liquid layer, using aqueous solutions of hydroxypropyl methylcellulose with different concentrations for variation of viscosity （1-300 mPa s）, In the presence of a liquid layer, increase of liquid viscosity decreases the restitution coefficient and the minimum thickness of the liquid layer at which the granule sticks to the wall. The measured restitution coefficients were compared with experiments performed without liquid layer. In contrast to the dry restitution coefficient, due to viscous losses at lower impact velocity, higher energy dissipation was obtained, A rational explanation for the effects obtained was given by results of numerically solved force and energy balances for a granule impact on a liquid layer on the wall. The model takes into account forces acting on the granule including viscous, surface tension, capillary, contact, drag, buoyancy and gravitational forces. Good agreement between simulations and experiments has been achieved.
文摘The reduction in noble metal content for efficient oxygen evolution catalysis is a crucial aspect towards the large scale commercialisation of polymer electrolyte membrane electrolyzers.Since catalytic stability and activity are inversely related,long service lifetime still demands large amounts of low-abundant and expensive iridium.In this manuscript we elaborate on the concept of maximizing the utilisation of iridium for the oxygen evolution reaction.By combining different tin oxide based support materials with liquid atomic layer deposition of iridium oxide,new possibilities are opened up to grow thin layers of iridium oxide with tuneable noble metal amounts.In-situ,time-and potential-resolved dissolution experiments reveal how the stability of the substrate and the catalyst layer thickness directly affect the activity and stability of deposited iridium oxide.Based on our results,we elaborate on strategies how to obtain stable and active catalysts with maximized iridium utilisation for the oxygen evolution reaction and demonstrate how the activity and durability can be tailored correspondingly.Our results highlight the potential of utilizing thin noble metal films with earth abundant support.materials for future catalytic applications in the energy sector.
基金supported by the National Natural Science Foundation of China(52075224,21975109,51975252,and 52075225)Natural Science Foundation of Jiangsu Province(BK20201423)+1 种基金Foundation of State Key Laboratory of Solid Lubrication(LSL-1801)Tribology Science Fund of State Key Laboratory of Tribology(SKLTKF18B03).
文摘Graphene(G),as a typical two-dimensional material,is often used as an additive for liquid lubricants.However,graphene is mostly added to liquid lubricants in a one-time manner in friction;it mainly exists in the form of multilayer agglomerated structures due to theπ–πstacking between graphene sheets,making it unable to fully exert the synergistic lubrication function.Herein,we propose a new macroscopic superlubric system of graphene/potassium hydroxide(G/KOH)solution;and the graphene additive involved is exfoliated in-situ from graphene/epoxy(G/EP)friction pair by friction,continuously providing freshly-peeled graphene into KOH solution and minimizing the adverse effects of graphene agglomeration.Moreover,the in-situ produced graphene additive has thinner thickness and better anti-aggregation ability,which provide more graphene to accommodate OH−,form more stacked sandwich structures of OH−/graphene/OH−between friction pairs(i.e.,equivalent to a moving pulley block with more wheels),and finally realize superlubricity.This study develops a new liquid superlubric system suitable for alkaline environments,and at the same time proposes a new way to gradually release graphene additives in situ,rather than adding them all at once,deepening the understanding to liquid superlubricity mechanism,and paving the experimental foundation for the practical application of macroscopic superlubricity.
基金supported by the National Natural Science Foundation of China(22008053,52002111)Key Research and Development Program of Hebei Province(20310601D,205A4401D)+2 种基金the Natural Science Foundation of Hebei Province(B2021208061,B2022208006,E2022208023)the Science Foundation of University of Hebei Province(BJ2020053)Beijing Natural Science Foundation(Z200011).
文摘Lithium metal batteries based on solid electrolytes are considered as promising candidates with high energy density and safety.However,the weak solid-solid contact between electrolyte and electrode can easily lead to interface instability and lithium ions discontinuous migration,which seriously reduces the electrochemical performance of the battery.Herein,we construct a soft gel interfacial layer to improve the stability of the solid-solid interface between electrolyte and electrode by means of polyester-based monomers and imidazole-based ionic liquids.Based on this,garnet-type Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)particles as inorganic ceramic filler were introduced in the layer to obtain composite electrolytes with high ionic conductivity(up to 1.1×10^(-3)S/cm at 25℃).As a result,the assembled lithium symmetric battery of Li|THCE-15%LLZTO|Li suggests excellent cycling stability with 700 h at 0.1 mA/cm^(2)at 50℃,and the lithium metal batteries of LFP|THCE-15%LLZTO|Li delivers high initial discharge capacity of 128.2 mA·h/g with capacity retain of 75.48%after 150 cycles at 2 C.This work paves a new route to build safe and stable lithium metal batteries with synergistic introduction of composite electrolytes between electrolyte and electrode using soft gel interfacial layer and inorganic filler.
基金Supported by Chinese Medicine(Ethnic Medicine)Standard Improvement Project of Sichuan Medical Products Administration(510201202102305)School Level Innovation Team of Fundamental Research Funds for the Central Universities(ZYN2022067)。
文摘[Objectives]To establish the quality standard of Oxyria sinensis Hemsl.[Methods]The method in Chinese Pharmacopoeia(2020 edition)was used to determine the moisture,total ash,acid-insoluble ash and alcohol-soluble extracts of O.sinensis.The qualitative identification of medicinal materials was carried out by microscopic identification method and thin layer chromatography(TLC).The contents of hyperoside and isoquercitrin were determined by high performance liquid chromatography(HPLC).[Results]The total amount of moisture,total ash,acid-insoluble ash,alcohol-soluble extract,hyperoside and isoquercitrin of 12 batches of medicinal materials were 8.56%-11.53%,11.26%-15.48%,1.62%-2.56%,17.75%-26.09%,and 0.036%-0.42%,respectively.The microscopic features were obvious,and pores,fibers,calcium oxalate clusters,calcium oxalate square crystals,cork cells could be observed.Fluorescent spots of the same color were displayed at the positions corresponding to the hyperoside reference substance.[Conclusions]Establishing relatively complete quality standards for O.sinensis medicinal materials can provide a reference for the quality control of medicinal materials.
