The effect of graft yield on both the thermo-responsive hydraulicpermeability and the therrno-responsive diffusional permeability through porous membranes withplasma-grafted poly(N-isopropylacrylamide) (PNIPAM) gates ...The effect of graft yield on both the thermo-responsive hydraulicpermeability and the therrno-responsive diffusional permeability through porous membranes withplasma-grafted poly(N-isopropylacrylamide) (PNIPAM) gates was investigated. Both thermo-responsiveflat membranes and core-shell microcapsule membranes with a wide range of graft yield of PNIPAM wereprepared using a plasma-graft pore-filling polymerization method. The grafted PNIPAM was formedhomogeneously throughout the entire thickness of both the flat polyethylene membranes and themicrocapsule polyamide membranes. Both the hydraulic permeability and the diffusional permeabilitywere heavily dependent on the PNIPAM graft yield. With increasing the graft yield, the hydraulicpermeability (water flux) decreases rapidly at 25℃ because of the decrease of the pore size;however, the water flux at 40℃ increases firstly to a peak because of the increase ofhydrophobicity of the pore surface, and then decreases and finally tends to zero because of the poresize becoming smaller and smaller. For the diffusional permeability, the temperature showsdifferent effects on the diffusional permeability coefficients of solutes across the membranes. Whenthe graft yield was low, the diffusional coefficient of solute across the membrane was higher attemperature above the lower critical solution temperature (LCST) than that below the LCST; however,when the graft yield was high, the diffusional coefficient was lower at temperature above the LCSTthan that below the LCST. It is very important to choose or design a proper graft yield of PNIPAMfor obtaining a desired thermo-responsive 'on/off' hydraulic or diffusional permeability.展开更多
Mechanism analysis on simultaneous oxidation of NO and SO2 with additives was presented and numerical simulation was developed to investigate the performances of three additives on oxidation of NO and SO2. The simulat...Mechanism analysis on simultaneous oxidation of NO and SO2 with additives was presented and numerical simulation was developed to investigate the performances of three additives on oxidation of NO and SO2. The simulation result showed that reaction temperature, residence time, additive dose and NO concentration influence the oxidation process significantly. There exists an optimum reaction condition for each additive, n-C4H10 has the strongest ability to oxidize NO and SO2.展开更多
A simple synthetic method has been described to prepare anisotropic gold nanoparticles （AuNPs） possessing unique optical and structural properties at room temperature, and subsequently the nanoparticles have been st...A simple synthetic method has been described to prepare anisotropic gold nanoparticles （AuNPs） possessing unique optical and structural properties at room temperature, and subsequently the nanoparticles have been stabilized by temperature-sensitive poly（N-isopropylacrylamide）, or poly（NIPAM）. Although poly（NIPAM） does not exhibit a strong binding affinity to gold, simply introducing poly（NIPAM） to these unstable anisotropic AuNPs can maintain the original structures and absorption properties for several weeks. This increased stability is presumably caused by the adsorbed polymer layer around the anisotropic AuNPs. The existence of adsorbed linear poly（NIPAM） around the AuNPs is confirmed through the reversible absorption properties of the nanoparticles upon heating and cooling. To verify the presence of weak attractive forces （e.g., van der Waals, dipole-dipole, and possible hydrogen bonding） between the polymer and the AuNPs, various concentrations of linear poly（NIPAM） are introduced during the formation of the AuNPs resulting in the systematical control of the size and roughness of the nanoparticles. In addition, the preferential attachment of pre-formed anisotropic AuNPs on cross-linked poly（NIPAM） nanoparticles indicates the presence of weak attractive forces between AuNPs and poly（NIPAM）. As such, poly（NIPAM） and its derivatives can serve as a useful stabilizing and capping agent to preserve the properties of the anisotropic AuNPs.展开更多
Quinary oxynitride BaNb_0.5Ta_0.5O_2N crystals were fabricated through the partial nitridation and acidifica- tion of the KCI flux grown Ba_5Nb_2Ta_2O_15 crystals. The parameters of both the solute concentrations and ...Quinary oxynitride BaNb_0.5Ta_0.5O_2N crystals were fabricated through the partial nitridation and acidifica- tion of the KCI flux grown Ba_5Nb_2Ta_2O_15 crystals. The parameters of both the solute concentrations and cooling rates are optimized for the KCI flux growth of the larger Ba_5Nb_2Ta_2O_15 crystals with clearer crystal habits. Here, the optimal Ba_5Nb_2Ta_2O_15 crystals mainly have a hexagonal plate-like shape. After the par- tial nitridation and acidification, the porous BaNb_0.5Ta_0.5O_2N crystals maintained the crystal shape of the oxide precursor and had a single-crystalline nature. For the BasNb2Ta2015 crystals, the wavelength of the absorption edge was about 707 nm. Especially, the CoOx-Ioaded BaNb_0.5Ta_0.5O_2N photocatalyst demon- strated the comparatively high amount of O_2 gas （150.7 μmol） during the 5 h visible-light-induced sacri- ficial water oxidation half-reaction, which might be achieved due to the high crystallinity and visible-light absorotion property.展开更多
The cracking of polyolefins, especially polyethylene in the molten state was effectively catalyzed by the powdery spent FCC （Fluid Catalytic Cracking） catalyst which was dispersed in it. The activation energy of the...The cracking of polyolefins, especially polyethylene in the molten state was effectively catalyzed by the powdery spent FCC （Fluid Catalytic Cracking） catalyst which was dispersed in it. The activation energy of the catalytic cracking of polyethylene was about 74 kJ/mol. The cracked product was naphtha and middle distillate as the major product and gaseous hydrocarbon （C1-C4） as the minor product while little heavy oil was produced. The chemical compositions of the product were： aromatic hydrocarbons, isoparaffins and branched olefins, whereas that of the non-catalyzed products were： n-olefins and n-paraffins with minor amount of dienes with increasing the process time. Additionally, the product pattern shifted from naphtha rich product to kerosene and gas-oil rich product. However, any catalytic product showed low fluid point （〈 -10 ℃）, while that of the non-catalyzed product was as high as 40 ℃. Catalyst could process, more than 100 times by weight of polyethylene with fairly small amount （- 30 wt%） of coke deposition. Spent catalyst gave higher hydrocarbons while fresh catalyst gave gaseous product as the major product. Other polyolefins such as polypropylene and polystyrene were tested on same catalyst to show that their reactivity is higher than that of polyethylene and gave the aliphatic products, alkyl benzenes and C6-C9 iso-paraffins as the major product. Product pattern of the cracked product suggested that the reaction proceeded via the primary reactions making paraffins and olefins which were followed by the isomerization, secondary cracking, aromatization and hydrogen transfer which based on the carbenium ion mechanism.展开更多
Certain perovskite-type oxynitrides have bandgaps suitable for renewable hydrogen production via photocatalytic and photoelectrochemical water splitting under visible light.Understanding the ordering of oxide and nitr...Certain perovskite-type oxynitrides have bandgaps suitable for renewable hydrogen production via photocatalytic and photoelectrochemical water splitting under visible light.Understanding the ordering of oxide and nitride anions in these materials is important because this ordering affects their semiconductor properties.However, the numerous possible orderings complicate systematic analyses based on density functional theory(DFT) calculations using defined elemental arrangements.This work shows that anion ordering in large-scale supercells within perovskite-type oxynitrides can be rapidly predicted based on machine learning, using BaNbO2N(capable of oxidizing water under irradiation up to 740 nm) as an example.Machine learning allows the calculation of the total energy of BaNbO2N directly from randomly selected initial atomic placements without costly structural optimization, thus reducing the computational cost by more than 99.99%.Combined with the Metropolis Monte Carlo method, machine learning permits exploration of the stable anion orderings of large supercells without costly DFT calculations.This work therefore demonstrates a means of predicting the properties of functional materials having complex compositions based on the most realistic elemental arrangements in conjunction with reasonable computational loads.展开更多
Cu/ZrO2/SiO2 are efficient catalysts for the selective hydrogenation of CO2 to CH3OH. In order to understand the role of ZrO2 in these mixed-oxides based catalysts, in situ X-ray absorption spectroscopy has been carri...Cu/ZrO2/SiO2 are efficient catalysts for the selective hydrogenation of CO2 to CH3OH. In order to understand the role of ZrO2 in these mixed-oxides based catalysts, in situ X-ray absorption spectroscopy has been carried out on the Cu and Zr K-edge. Under reaction conditions, Cu remains metallic, while Zr is present in three types of coordination environment associated with 1) bulk ZrO2, 2) coordinatively saturated and 3) unsaturated Zr(Ⅳ) surface sites. The amount of coordinatively unsaturated Zr surface sites can be quantified by linear combination fit of reference X-Ray absorption near edge structure (XANES) spectra and its amount correlates with CH3OH formation rates, thus indicating the importance of Zr(Ⅳ) Lewis acid surface sites in driving the selectivity toward CH3OH. This finding is consistent with the proposed mechanism, where CO2 is hydrogenated at the interface between the Cu nanoparticles that split H2 and Zr(Ⅳ) surface sites that stabilizes reaction intermediates.展开更多
Magnesium(Mg)alloys for metal electroplating require a surface pretreatment,i.e.,the removal of the spontaneously oxidized surface layer(MgO,Mg(OH)_(2),andMgCO_(3)).However,the use of highly toxic and/or corrosive aci...Magnesium(Mg)alloys for metal electroplating require a surface pretreatment,i.e.,the removal of the spontaneously oxidized surface layer(MgO,Mg(OH)_(2),andMgCO_(3)).However,the use of highly toxic and/or corrosive acids in conventional pretreatment processes has become an issue.In this study,a facile and less toxic pretreatment is demonstrated and applied in aluminum(Al)electroplating.The immersion of the AZ31 Mg alloy into acetic anhydride(Ac_(2)O)removed the spontaneously oxidized surface layer and formed a thin but stable magnesium acetate(Mg(OAc)_(2))layer that protects the metal substrate from further oxidation.The Al electroplating bath is a concentrated diglyme(G2)-AlCl_(3)organic solution that can readily dissolve Mg(OAc)_(2)to enable direct plating onto a metal substrate.The as-deposited Al layer has a compact and crack-free morphology that improves the corrosion resistance and hardness(2.7 GPa).Owing to the lack of an interfacial oxidized layer,heat treatment led to the successful diff usion of Mg and Al atoms,which increased the hardness to 4.4 GPa.The Ac_(2)O pretreatment of Mg alloys enables the successful Al electroplating and subsequent heat treatment.展开更多
Exploration of novel narrow bandgap semiconductors for overall water splitting is vital for the realization of practical solar H2 production.In the work,solid solutions of zinc selenide and copper gallium selenide wit...Exploration of novel narrow bandgap semiconductors for overall water splitting is vital for the realization of practical solar H2 production.In the work,solid solutions of zinc selenide and copper gallium selenide with absorption edge wavelengths ranging from 480 to 730 nm were developed.Using these metal selenides as H2-evolving photocatalysts,CoOx/BiVO4 as the O2-evolving photocatalyst,and reduced graphene oxide as the electron mediator,all-solid-state Z-scheme overall pure water splitting systems were constructed.The rate of photocatalytic H2 evolution from aqueous solutions containing Na2S and Na2SO3 as the electron donors was evaluated while employing these selenide photocatalysts at various Zn/(Zn+Cu)and Ga/Cu molar ratios.The data demonstrate that efficient Z-scheme overall water splitting was significantly correlated to the photoelectrochemical performance of the selenide photocatalysts acting as photocathodes,rather than the photocatalytic activities of these materials during the sacrificial H2 evolution.展开更多
We presented a control strategy for tablet manufacturing processes based on continuous direct compression.The work was conducted by the experts of pharmaceutical companies,machine suppliers,academia,and regulatory aut...We presented a control strategy for tablet manufacturing processes based on continuous direct compression.The work was conducted by the experts of pharmaceutical companies,machine suppliers,academia,and regulatory authority in Japan.Among different items in the process,the component ratio and blended powder content were selected as the items requiring the control method specific to continuous manufacturing different from the conventional batch manufacturing.The control and management of the Loss in Weight(LIW)feeder were deemed the most important,and the Residence Time Distribution(RTD)model were regarded effective for setting the control range and for controlling of the LIW feeder.Based on these ideas,the concept of process control using RTD was summarized.展开更多
Despite a continuing increase in the number of patients suffering from chronic kidney disease,currently available treatments for these patients,such as dialysis and kidney transplantation,are imperfect.The kidney is a...Despite a continuing increase in the number of patients suffering from chronic kidney disease,currently available treatments for these patients,such as dialysis and kidney transplantation,are imperfect.The kidney is also a critical target organ vulnerable to the toxicity of various new drugs,and the lack of a reliable in vitro culture model imposes a severe limitation on drug discovery.Although the development of induced pluripotent stem cells(iPSCs)revolutionized strategies in biomedical fields,the complexity of the kidney imposed additional challenge to the application of this technology in kidney regeneration.Nonetheless,the recent advancement in our understanding on the developmental origin of kidney progenitor cells and the mechanisms of their reciprocal induction and self-organization has boosted research in kidney regeneration.Research since then has demonstrated that kidney organoids derived from iPSCs can serve as a useful model for drug discovery and toxicity screening,as well as for disease modeling,especially in combination with gene editing techniques.Moreover,attempts at kidney organoid implantation in animals have suggested their potential as an alternative source of kidney transplantation.In this review,we summarize recent progress on the generation of kidney organoids,as well as the obstacles that remain.展开更多
Based on non-isothermal experimental results for eight Chinese biomass species, a new kinetic model, named as the 損seudo bi-component separate-stage model (PBSM)? is developed in this note to describe the mass loss b...Based on non-isothermal experimental results for eight Chinese biomass species, a new kinetic model, named as the 損seudo bi-component separate-stage model (PBSM)? is developed in this note to describe the mass loss behavior of biomass thermal decomposition. This model gains an advantage over the commonly used 損seudo single-component overall model (PSOM)?and 損seudo multi-component overall model (PMOM)? By means of integral analysis it is indicated that the new model is suitable to describe the mass loss kinetics of wood and leaf samples under relatively low heating rates (e.g. 10℃/min, used in this work).展开更多
Copper oxide nanowires with varying oxidation states are prepared and their activity for water oxidation is studied. The nanowires with a CuO phase are found to be the most active, and their degree of crystallinity is...Copper oxide nanowires with varying oxidation states are prepared and their activity for water oxidation is studied. The nanowires with a CuO phase are found to be the most active, and their degree of crystallinity is important in achieving efficient water oxidation. For the crystalline CuO nanowires in a weakly basic Na2CO3 electrolyte, a Tafel slope of 41 mV/decade, an overpotential of approximately 500 mV at - 10 mA/crn2 （without compensation for the solution resistance）, and a faradaic efficiency of nearly 100% are obtained. This electrode maintains a stable current for over 15 lx The low overpotential of 500 mV at 10 mA/cm2, small Tafel slope, long-term stability, and low cost make CuO one of the most promising catalysts for water oxidation. Moreover, the evolution of the CuO nanowire morphology over time is studied by electron microscop）-revealing that the diffusion of Cu ions from the interior of the nanowires to their surface causes the aggregation of individual nanowires over time. However, despite this aggregation, the current density remains nearly constant, because the total electrochemically active surface area of CuO does not change.展开更多
Cyclohexane dehydrogenation in the solar-driven membrane reactor is a promising method of directly producing pure hydrogen and benzene from cyclohexane and storing low-grade solar energy as high-grade chemical energy....Cyclohexane dehydrogenation in the solar-driven membrane reactor is a promising method of directly producing pure hydrogen and benzene from cyclohexane and storing low-grade solar energy as high-grade chemical energy.In this paper,partial pressure of gases,conversion rate of cyclohexane,and energy efficiency of the reactor are analyzed based on numerical simulation.The process of cyclohexane dehydrogenation under four temperatures(200℃,250℃,300℃,and 350℃)and four permeate pressures(0.050 MPa,0.025 MPa,0.010 MPa,and 0.001 MPa)were studied.A complete conversion rate(99.9%)of cyclohexane was obtained as the reaction equilibrium shifts forward with hydrogen separation.The first-law thermodynamic efficiency,solar-to-fuel efficiency,and exergy efficiency could reach as high as 94.69%,46.93%and 93.08%,respectively.This study indicates that it is feasible to combine solar energy supply technology with cyclohexane dehydrogenation reaction integrated with membrane reactor.展开更多
The physicochemical properties of a specific ionic liquid(IL)are naturally considered to be constant at a given temperature.However,a series of eutectic melts of trihexyl(tetradecyl)phosphonium chloride([P6,6,6,14]Cl)...The physicochemical properties of a specific ionic liquid(IL)are naturally considered to be constant at a given temperature.However,a series of eutectic melts of trihexyl(tetradecyl)phosphonium chloride([P6,6,6,14]Cl)with aluminum chloride(AlCl3)is an exception.The viscosity of Al_(2)Cl_(7)−-dominated[P6,6,6,14]Cl–AlCl_(3)ILs(i.e.,AlCl_(3)mole fraction x=0.60–0.67)gradually increased as a function of annealing.Annealing also influenced the ultraviolet–visible spectra,nuclear magnetic resonance spectra,and the glass transition temperature of the ILs.Such annealing-induced variations in physicochemical properties were not observed in the AlCl4−-and Cl−-dominated ILs.In particular,the ionic conductivities of the ILs(x=0.60–0.67)were strongly decoupled from their viscosities during annealing.Ab initio calculations revealed the bending of the long tetradecyl chains in[P6,6,6,14]+coupled with Al_(2)Cl_(7)−,while neither Cl−nor AlCl_(4)−caused bending.In general,[P6,6,6,14]+-based ILs are recognized as sponge-like structures that consist of nano-scale polar and non-polar domains.We propose a gradual structurization process in Al_(2)Cl_(7)−-dominated ILs to account for their unusual physicochemical properties.Moreover,the addition of tetradecane,solvated in the non-polar domains of the ILs,substantially reduced the viscosity of the structured IL with x=0.67.Mirror Al electroplating is possible without a brightener,using the x=0.67 ILs,regardless of annealing or the admixture of tetradecane.展开更多
CONSPECTUS:Sustainable development cannot be achieved without substantial technological advancements.For instance,flexible electricity management requires smart power sourcing with advanced energy storage/conversion t...CONSPECTUS:Sustainable development cannot be achieved without substantial technological advancements.For instance,flexible electricity management requires smart power sourcing with advanced energy storage/conversion technologies.Remedies for abrupt power spikes/drops observed in renewable energy sources such as solar and wind require rapid load-leveling using high-power energy storage systems when they are integrated into a microgrid.Electrochemical energy storage devices efficiently convert electrical and chemical energy,which can potentially function as distributed power sources.Among these,lithium-ion batteries are a present de facto standard with their relatively high energy density and energy efficiencies that are based on topochemical intercalation chemistry,whereby vip lithium ions are(de)intercalated reversibly with simultaneous redox reactions and minimal structural changes.However,their energy density,power density,life-cycle cost,calendar life,and safety remain unsatisfactory for widespread use.When the storage capacity is maximized,as a result of which a labile deep charge/discharge state is generated,to develop batteries with high energy density,subsequent irreversible phase transformations or chemical reactions occur in many cases.The combination of the reversible electrode reactions and the subsequent irreversible phase transformations sometimes causes a charge/discharge curve characterized by a large voltage hysteresis with 100%Coulombic efficiency.Because a large voltage hysteresis significantly degrades the energy efficiency,unveiling the reaction mechanism is of primary importance in mitigating energy loss.展开更多
基金Supported by the National Natural Science Foundation of China(No.29876022).
文摘The effect of graft yield on both the thermo-responsive hydraulicpermeability and the therrno-responsive diffusional permeability through porous membranes withplasma-grafted poly(N-isopropylacrylamide) (PNIPAM) gates was investigated. Both thermo-responsiveflat membranes and core-shell microcapsule membranes with a wide range of graft yield of PNIPAM wereprepared using a plasma-graft pore-filling polymerization method. The grafted PNIPAM was formedhomogeneously throughout the entire thickness of both the flat polyethylene membranes and themicrocapsule polyamide membranes. Both the hydraulic permeability and the diffusional permeabilitywere heavily dependent on the PNIPAM graft yield. With increasing the graft yield, the hydraulicpermeability (water flux) decreases rapidly at 25℃ because of the decrease of the pore size;however, the water flux at 40℃ increases firstly to a peak because of the increase ofhydrophobicity of the pore surface, and then decreases and finally tends to zero because of the poresize becoming smaller and smaller. For the diffusional permeability, the temperature showsdifferent effects on the diffusional permeability coefficients of solutes across the membranes. Whenthe graft yield was low, the diffusional coefficient of solute across the membrane was higher attemperature above the lower critical solution temperature (LCST) than that below the LCST; however,when the graft yield was high, the diffusional coefficient was lower at temperature above the LCSTthan that below the LCST. It is very important to choose or design a proper graft yield of PNIPAMfor obtaining a desired thermo-responsive 'on/off' hydraulic or diffusional permeability.
文摘Mechanism analysis on simultaneous oxidation of NO and SO2 with additives was presented and numerical simulation was developed to investigate the performances of three additives on oxidation of NO and SO2. The simulation result showed that reaction temperature, residence time, additive dose and NO concentration influence the oxidation process significantly. There exists an optimum reaction condition for each additive, n-C4H10 has the strongest ability to oxidize NO and SO2.
基金supported by Korea Ministry of Environment as The Eco-Innovation Project (Global Top project,No.GT-SWS-11-01-0040-0)
文摘A simple synthetic method has been described to prepare anisotropic gold nanoparticles （AuNPs） possessing unique optical and structural properties at room temperature, and subsequently the nanoparticles have been stabilized by temperature-sensitive poly（N-isopropylacrylamide）, or poly（NIPAM）. Although poly（NIPAM） does not exhibit a strong binding affinity to gold, simply introducing poly（NIPAM） to these unstable anisotropic AuNPs can maintain the original structures and absorption properties for several weeks. This increased stability is presumably caused by the adsorbed polymer layer around the anisotropic AuNPs. The existence of adsorbed linear poly（NIPAM） around the AuNPs is confirmed through the reversible absorption properties of the nanoparticles upon heating and cooling. To verify the presence of weak attractive forces （e.g., van der Waals, dipole-dipole, and possible hydrogen bonding） between the polymer and the AuNPs, various concentrations of linear poly（NIPAM） are introduced during the formation of the AuNPs resulting in the systematical control of the size and roughness of the nanoparticles. In addition, the preferential attachment of pre-formed anisotropic AuNPs on cross-linked poly（NIPAM） nanoparticles indicates the presence of weak attractive forces between AuNPs and poly（NIPAM）. As such, poly（NIPAM） and its derivatives can serve as a useful stabilizing and capping agent to preserve the properties of the anisotropic AuNPs.
基金supported in part by the Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem)
文摘Quinary oxynitride BaNb_0.5Ta_0.5O_2N crystals were fabricated through the partial nitridation and acidifica- tion of the KCI flux grown Ba_5Nb_2Ta_2O_15 crystals. The parameters of both the solute concentrations and cooling rates are optimized for the KCI flux growth of the larger Ba_5Nb_2Ta_2O_15 crystals with clearer crystal habits. Here, the optimal Ba_5Nb_2Ta_2O_15 crystals mainly have a hexagonal plate-like shape. After the par- tial nitridation and acidification, the porous BaNb_0.5Ta_0.5O_2N crystals maintained the crystal shape of the oxide precursor and had a single-crystalline nature. For the BasNb2Ta2015 crystals, the wavelength of the absorption edge was about 707 nm. Especially, the CoOx-Ioaded BaNb_0.5Ta_0.5O_2N photocatalyst demon- strated the comparatively high amount of O_2 gas （150.7 μmol） during the 5 h visible-light-induced sacri- ficial water oxidation half-reaction, which might be achieved due to the high crystallinity and visible-light absorotion property.
文摘The cracking of polyolefins, especially polyethylene in the molten state was effectively catalyzed by the powdery spent FCC （Fluid Catalytic Cracking） catalyst which was dispersed in it. The activation energy of the catalytic cracking of polyethylene was about 74 kJ/mol. The cracked product was naphtha and middle distillate as the major product and gaseous hydrocarbon （C1-C4） as the minor product while little heavy oil was produced. The chemical compositions of the product were： aromatic hydrocarbons, isoparaffins and branched olefins, whereas that of the non-catalyzed products were： n-olefins and n-paraffins with minor amount of dienes with increasing the process time. Additionally, the product pattern shifted from naphtha rich product to kerosene and gas-oil rich product. However, any catalytic product showed low fluid point （〈 -10 ℃）, while that of the non-catalyzed product was as high as 40 ℃. Catalyst could process, more than 100 times by weight of polyethylene with fairly small amount （- 30 wt%） of coke deposition. Spent catalyst gave higher hydrocarbons while fresh catalyst gave gaseous product as the major product. Other polyolefins such as polypropylene and polystyrene were tested on same catalyst to show that their reactivity is higher than that of polyethylene and gave the aliphatic products, alkyl benzenes and C6-C9 iso-paraffins as the major product. Product pattern of the cracked product suggested that the reaction proceeded via the primary reactions making paraffins and olefins which were followed by the isomerization, secondary cracking, aromatization and hydrogen transfer which based on the carbenium ion mechanism.
基金financially supported by Grants-in-Aid for Scientific Research (A) (no.16H02417)Young Scientists (A) (no.15H05494) from the Japan Society for the Promotion of Science (JSPS)partly supported by MEXT as “Priority Issue on Post-K computer” (Development of new fundamental technologies for highefficiency energy creation, conversion/storage and use)
文摘Certain perovskite-type oxynitrides have bandgaps suitable for renewable hydrogen production via photocatalytic and photoelectrochemical water splitting under visible light.Understanding the ordering of oxide and nitride anions in these materials is important because this ordering affects their semiconductor properties.However, the numerous possible orderings complicate systematic analyses based on density functional theory(DFT) calculations using defined elemental arrangements.This work shows that anion ordering in large-scale supercells within perovskite-type oxynitrides can be rapidly predicted based on machine learning, using BaNbO2N(capable of oxidizing water under irradiation up to 740 nm) as an example.Machine learning allows the calculation of the total energy of BaNbO2N directly from randomly selected initial atomic placements without costly structural optimization, thus reducing the computational cost by more than 99.99%.Combined with the Metropolis Monte Carlo method, machine learning permits exploration of the stable anion orderings of large supercells without costly DFT calculations.This work therefore demonstrates a means of predicting the properties of functional materials having complex compositions based on the most realistic elemental arrangements in conjunction with reasonable computational loads.
基金E.L.,K.L.,P.W.,and S.T.are supported by the SCCER-Heat and Energy Storage program
文摘Cu/ZrO2/SiO2 are efficient catalysts for the selective hydrogenation of CO2 to CH3OH. In order to understand the role of ZrO2 in these mixed-oxides based catalysts, in situ X-ray absorption spectroscopy has been carried out on the Cu and Zr K-edge. Under reaction conditions, Cu remains metallic, while Zr is present in three types of coordination environment associated with 1) bulk ZrO2, 2) coordinatively saturated and 3) unsaturated Zr(Ⅳ) surface sites. The amount of coordinatively unsaturated Zr surface sites can be quantified by linear combination fit of reference X-Ray absorption near edge structure (XANES) spectra and its amount correlates with CH3OH formation rates, thus indicating the importance of Zr(Ⅳ) Lewis acid surface sites in driving the selectivity toward CH3OH. This finding is consistent with the proposed mechanism, where CO2 is hydrogenated at the interface between the Cu nanoparticles that split H2 and Zr(Ⅳ) surface sites that stabilizes reaction intermediates.
基金financially supported by KAKENHI(No.22K14508:Z.Z.,No.19H02490 and No.19K22056:A.K.,No.20H05663:K.M.)from the Japan Society for the Promotion of Science(JSPS)。
文摘Magnesium(Mg)alloys for metal electroplating require a surface pretreatment,i.e.,the removal of the spontaneously oxidized surface layer(MgO,Mg(OH)_(2),andMgCO_(3)).However,the use of highly toxic and/or corrosive acids in conventional pretreatment processes has become an issue.In this study,a facile and less toxic pretreatment is demonstrated and applied in aluminum(Al)electroplating.The immersion of the AZ31 Mg alloy into acetic anhydride(Ac_(2)O)removed the spontaneously oxidized surface layer and formed a thin but stable magnesium acetate(Mg(OAc)_(2))layer that protects the metal substrate from further oxidation.The Al electroplating bath is a concentrated diglyme(G2)-AlCl_(3)organic solution that can readily dissolve Mg(OAc)_(2)to enable direct plating onto a metal substrate.The as-deposited Al layer has a compact and crack-free morphology that improves the corrosion resistance and hardness(2.7 GPa).Owing to the lack of an interfacial oxidized layer,heat treatment led to the successful diff usion of Mg and Al atoms,which increased the hardness to 4.4 GPa.The Ac_(2)O pretreatment of Mg alloys enables the successful Al electroplating and subsequent heat treatment.
基金financially supported by the Artificial Photosynthesis Project of the New Energy and Industrial Technology Development Organization(NEDO)Grant-in-Aids for Scientific Research(A)(No.16H02417)Young Scientists(A)(No.15H05494)from the Japan Society for the Promotion of Science(JSPS)
文摘Exploration of novel narrow bandgap semiconductors for overall water splitting is vital for the realization of practical solar H2 production.In the work,solid solutions of zinc selenide and copper gallium selenide with absorption edge wavelengths ranging from 480 to 730 nm were developed.Using these metal selenides as H2-evolving photocatalysts,CoOx/BiVO4 as the O2-evolving photocatalyst,and reduced graphene oxide as the electron mediator,all-solid-state Z-scheme overall pure water splitting systems were constructed.The rate of photocatalytic H2 evolution from aqueous solutions containing Na2S and Na2SO3 as the electron donors was evaluated while employing these selenide photocatalysts at various Zn/(Zn+Cu)and Ga/Cu molar ratios.The data demonstrate that efficient Z-scheme overall water splitting was significantly correlated to the photoelectrochemical performance of the selenide photocatalysts acting as photocathodes,rather than the photocatalytic activities of these materials during the sacrificial H2 evolution.
文摘We presented a control strategy for tablet manufacturing processes based on continuous direct compression.The work was conducted by the experts of pharmaceutical companies,machine suppliers,academia,and regulatory authority in Japan.Among different items in the process,the component ratio and blended powder content were selected as the items requiring the control method specific to continuous manufacturing different from the conventional batch manufacturing.The control and management of the Loss in Weight(LIW)feeder were deemed the most important,and the Residence Time Distribution(RTD)model were regarded effective for setting the control range and for controlling of the LIW feeder.Based on these ideas,the concept of process control using RTD was summarized.
文摘Despite a continuing increase in the number of patients suffering from chronic kidney disease,currently available treatments for these patients,such as dialysis and kidney transplantation,are imperfect.The kidney is also a critical target organ vulnerable to the toxicity of various new drugs,and the lack of a reliable in vitro culture model imposes a severe limitation on drug discovery.Although the development of induced pluripotent stem cells(iPSCs)revolutionized strategies in biomedical fields,the complexity of the kidney imposed additional challenge to the application of this technology in kidney regeneration.Nonetheless,the recent advancement in our understanding on the developmental origin of kidney progenitor cells and the mechanisms of their reciprocal induction and self-organization has boosted research in kidney regeneration.Research since then has demonstrated that kidney organoids derived from iPSCs can serve as a useful model for drug discovery and toxicity screening,as well as for disease modeling,especially in combination with gene editing techniques.Moreover,attempts at kidney organoid implantation in animals have suggested their potential as an alternative source of kidney transplantation.In this review,we summarize recent progress on the generation of kidney organoids,as well as the obstacles that remain.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 59876039 59936140) the National Key Basic ResearchProgramm of China the China-Greece Joint Project 揑nvestigation on the Characteristics of Forest Fire in the Ear
文摘Based on non-isothermal experimental results for eight Chinese biomass species, a new kinetic model, named as the 損seudo bi-component separate-stage model (PBSM)? is developed in this note to describe the mass loss behavior of biomass thermal decomposition. This model gains an advantage over the commonly used 損seudo single-component overall model (PSOM)?and 損seudo multi-component overall model (PMOM)? By means of integral analysis it is indicated that the new model is suitable to describe the mass loss kinetics of wood and leaf samples under relatively low heating rates (e.g. 10℃/min, used in this work).
文摘Copper oxide nanowires with varying oxidation states are prepared and their activity for water oxidation is studied. The nanowires with a CuO phase are found to be the most active, and their degree of crystallinity is important in achieving efficient water oxidation. For the crystalline CuO nanowires in a weakly basic Na2CO3 electrolyte, a Tafel slope of 41 mV/decade, an overpotential of approximately 500 mV at - 10 mA/crn2 （without compensation for the solution resistance）, and a faradaic efficiency of nearly 100% are obtained. This electrode maintains a stable current for over 15 lx The low overpotential of 500 mV at 10 mA/cm2, small Tafel slope, long-term stability, and low cost make CuO one of the most promising catalysts for water oxidation. Moreover, the evolution of the CuO nanowire morphology over time is studied by electron microscop）-revealing that the diffusion of Cu ions from the interior of the nanowires to their surface causes the aggregation of individual nanowires over time. However, despite this aggregation, the current density remains nearly constant, because the total electrochemically active surface area of CuO does not change.
基金This work is funded by the National Natural Science Foundation of China(No.51906179)the China Scholarship Council(No.201906275035)the National Key Research and Development Program of China(No.2018YFC0808401).
文摘Cyclohexane dehydrogenation in the solar-driven membrane reactor is a promising method of directly producing pure hydrogen and benzene from cyclohexane and storing low-grade solar energy as high-grade chemical energy.In this paper,partial pressure of gases,conversion rate of cyclohexane,and energy efficiency of the reactor are analyzed based on numerical simulation.The process of cyclohexane dehydrogenation under four temperatures(200℃,250℃,300℃,and 350℃)and four permeate pressures(0.050 MPa,0.025 MPa,0.010 MPa,and 0.001 MPa)were studied.A complete conversion rate(99.9%)of cyclohexane was obtained as the reaction equilibrium shifts forward with hydrogen separation.The first-law thermodynamic efficiency,solar-to-fuel efficiency,and exergy efficiency could reach as high as 94.69%,46.93%and 93.08%,respectively.This study indicates that it is feasible to combine solar energy supply technology with cyclohexane dehydrogenation reaction integrated with membrane reactor.
基金supported by the Japan Society for the Promotion of Science(JSPS,No.22K14508:Z.L.Z.No.22H01830:A.K.+2 种基金No.20H05663:K.M.)the Joint Usage/Research Program on Zero-Emission Energy Research,Institute of Advanced Energy,Kyoto University(ZE2022A-01)Z.Z.also acknowledges the financial support of the Kyoto University Research Fund for Young Scientists(Start-up).
文摘The physicochemical properties of a specific ionic liquid(IL)are naturally considered to be constant at a given temperature.However,a series of eutectic melts of trihexyl(tetradecyl)phosphonium chloride([P6,6,6,14]Cl)with aluminum chloride(AlCl3)is an exception.The viscosity of Al_(2)Cl_(7)−-dominated[P6,6,6,14]Cl–AlCl_(3)ILs(i.e.,AlCl_(3)mole fraction x=0.60–0.67)gradually increased as a function of annealing.Annealing also influenced the ultraviolet–visible spectra,nuclear magnetic resonance spectra,and the glass transition temperature of the ILs.Such annealing-induced variations in physicochemical properties were not observed in the AlCl4−-and Cl−-dominated ILs.In particular,the ionic conductivities of the ILs(x=0.60–0.67)were strongly decoupled from their viscosities during annealing.Ab initio calculations revealed the bending of the long tetradecyl chains in[P6,6,6,14]+coupled with Al_(2)Cl_(7)−,while neither Cl−nor AlCl_(4)−caused bending.In general,[P6,6,6,14]+-based ILs are recognized as sponge-like structures that consist of nano-scale polar and non-polar domains.We propose a gradual structurization process in Al_(2)Cl_(7)−-dominated ILs to account for their unusual physicochemical properties.Moreover,the addition of tetradecane,solvated in the non-polar domains of the ILs,substantially reduced the viscosity of the structured IL with x=0.67.Mirror Al electroplating is possible without a brightener,using the x=0.67 ILs,regardless of annealing or the admixture of tetradecane.
基金This work was financially supported by a Ministry of Education,Culture,Sports,Science and Technology(MEXT),Japan,Grant-in-Aid for Scientific Research(S)(no.20H05673)This work was also supported by the“Elements Strategy Initiative for Catalysts and Batteries(ESICB)”.M.O.was financially supported by the Japan Society for the Promotion of Science(JPSP)KAKENHI(grant nos.19H05816,18K19124,and 21H04697)the Asahi Glass Foundation.
文摘CONSPECTUS:Sustainable development cannot be achieved without substantial technological advancements.For instance,flexible electricity management requires smart power sourcing with advanced energy storage/conversion technologies.Remedies for abrupt power spikes/drops observed in renewable energy sources such as solar and wind require rapid load-leveling using high-power energy storage systems when they are integrated into a microgrid.Electrochemical energy storage devices efficiently convert electrical and chemical energy,which can potentially function as distributed power sources.Among these,lithium-ion batteries are a present de facto standard with their relatively high energy density and energy efficiencies that are based on topochemical intercalation chemistry,whereby vip lithium ions are(de)intercalated reversibly with simultaneous redox reactions and minimal structural changes.However,their energy density,power density,life-cycle cost,calendar life,and safety remain unsatisfactory for widespread use.When the storage capacity is maximized,as a result of which a labile deep charge/discharge state is generated,to develop batteries with high energy density,subsequent irreversible phase transformations or chemical reactions occur in many cases.The combination of the reversible electrode reactions and the subsequent irreversible phase transformations sometimes causes a charge/discharge curve characterized by a large voltage hysteresis with 100%Coulombic efficiency.Because a large voltage hysteresis significantly degrades the energy efficiency,unveiling the reaction mechanism is of primary importance in mitigating energy loss.
