Subretinal fibrosis is the end-stage sequelae of neovascular age-related macular degeneration.It causes local damage to photoreceptors,retinal pigment epithelium,and choroidal vessels,which leads to permanent central ...Subretinal fibrosis is the end-stage sequelae of neovascular age-related macular degeneration.It causes local damage to photoreceptors,retinal pigment epithelium,and choroidal vessels,which leads to permanent central vision loss of patients with neovascular age-related macular degeneration.The pathogenesis of subretinal fibrosis is complex,and the underlying mechanisms are largely unknown.Therefore,there are no effective treatment options.A thorough understanding of the pathogenesis of subretinal fibrosis and its related mechanisms is important to elucidate its complications and explore potential treatments.The current article reviews several aspects of subretinal fibrosis,including the current understanding on the relationship between neovascular age-related macular degeneration and subretinal fibrosis;multimodal imaging techniques for subretinal fibrosis;animal models for studying subretinal fibrosis;cellular and non-cellular constituents of subretinal fibrosis;pathophysiological mechanisms involved in subretinal fibrosis,such as aging,infiltration of macrophages,different sources of mesenchymal transition to myofibroblast,and activation of complement system and immune cells;and several key molecules and signaling pathways participating in the pathogenesis of subretinal fibrosis,such as vascular endothelial growth factor,connective tissue growth factor,fibroblast growth factor 2,platelet-derived growth factor and platelet-derived growth factor receptor-β,transforming growth factor-βsignaling pathway,Wnt signaling pathway,and the axis of heat shock protein 70-Toll-like receptors 2/4-interleukin-10.This review will improve the understanding of the pathogenesis of subretinal fibrosis,allow the discovery of molecular targets,and explore potential treatments for the management of subretinal fibrosis.展开更多
Green hydrogen from electrolysis of water has attracted widespread attention as a renewable power source.Among several hydrogen production methods,it has become the most promising technology.However,there is no large-...Green hydrogen from electrolysis of water has attracted widespread attention as a renewable power source.Among several hydrogen production methods,it has become the most promising technology.However,there is no large-scale renewable hydrogen production system currently that can compete with conventional fossil fuel hydrogen production.Renewable energy electrocatalytic water splitting is an ideal production technology with environmental cleanliness protection and good hydrogen purity,which meet the requirements of future development.This review summarizes and introduces the current status of hydrogen production by water splitting from three aspects:electricity,catalyst and electrolyte.In particular,the present situation and the latest progress of the key sources of power,catalytic materials and electrolyzers for electrocatalytic water splitting are introduced.Finally,the problems of hydrogen generation from electrolytic water splitting and directions of next-generation green hydrogen in the future are discussed and outlooked.It is expected that this review will have an important impact on the field of hydrogen production from water.展开更多
Seamless prediction is a weather-climate integrated prediction covering multiple time scales that include days,weeks,months,seasons,years,and decades.Seamless prediction can provide different industries with informati...Seamless prediction is a weather-climate integrated prediction covering multiple time scales that include days,weeks,months,seasons,years,and decades.Seamless prediction can provide different industries with information such as weather conditions and climate variations from the next few days to years,which have important impacts on economic and social development and important reference value for short-,medium-and long-term decision-making and planning of the country.Therefore,seamless prediction has received widespread attention from the international scientific community recently.As Chinese scientists have also carried out relevant research,this paper reviews the research in China on developments and applications of seamless prediction methods and prediction systems in recent years.Among them,the main progress of seamless prediction methods studies is reviewed from four aspects:short-and medium-range weather forecasting,subseasonal-to-seasonal,seasonal-to-interannual,and decadal climate prediction.In terms of development and application of seamless prediction systems,the main achievements made by meteorological operational departments,scientific institutes,and universities in China in recent years are reviewed.Finally,some of the issues in seamless prediction that need further study are discussed.展开更多
Due to the bus characteristics of large quality,high center of gravity and narrow wheelbase,the research of its yaw stability control(YSC)system has become the focus in the field of vehicle system dynamics.However,the...Due to the bus characteristics of large quality,high center of gravity and narrow wheelbase,the research of its yaw stability control(YSC)system has become the focus in the field of vehicle system dynamics.However,the tire nonlinear mechanical properties and the effectiveness of the YSC control system are not considered carefully in the current research.In this paper,a novel adaptive nonsingular fast terminal sliding mode(ANFTSM)control scheme for YSC is proposed to improve the bus curve driving stability and safety on slippery roads.Firstly,the STI(Systems Technologies Inc.)tire model,which can effectively reflect the nonlinear coupling relationship between the tire longitudinal force and lateral force,is established based on experimental data and firstly adopted in the bus YSC system design.On this basis,a more accurate bus lateral dynamics model is built and a novel YSC strategy based on ANFTSM,which has the merits of fast transient response,finite time convergence and high robustness against uncertainties and external disturbances,is designed.Thirdly,to solve the optimal allocation problem of the tire forces,whose objective is to achieve the desired direct yaw moment through the effective distribution of the brake force of each tire,the robust least-squares allocation method is adopted.To verify the feasibility,effectiveness and practicality of the proposed bus YSC approach,the TruckSim-Simulink co-simulation results are finally provided.The co-simulation results show that the lateral stability of bus under special driving conditions has been significantly improved.This research proposes a more effective design method for bus YSC system based on a more accurate tire model.展开更多
[Objective]This study was conducted to evaluate the soil fertility in Yiliantobacco-growing areas of Hunan Province.[Method]The soil nutrient contents iseven tobacco-growing towns of Yiliang County,Yunnan Province wer...[Objective]This study was conducted to evaluate the soil fertility in Yiliantobacco-growing areas of Hunan Province.[Method]The soil nutrient contents iseven tobacco-growing towns of Yiliang County,Yunnan Province were surveyefrom 2010 to 2013 and integrated soil fertility index(SFI value)was calculated tanalyze the soil fertility suitability in theses areas.[Result]The soil p H,contents oorganic matter,hydrolytic N,rapidly available K and available B were all at an appropriate level,while the contents of rapidly available P,available Mg,available Zand water-soluble Cl-were high.Among them,the contents of available P and water-soluble Cl-had great variation.Finally,the soil fertility suitability of Yiliang tobacco-growing areas was graded based on their SFI values.As a result,20%of thestobacco-growing areas were in Grade I,47.7%in Grade II,29.3%in Grade III1.5%in Grade IV and 1.5%in Grade V.The average SFI was 0.61.From 2010 t2013,the p H value and available Mg content reduced year by year,while the contents of organic matter,hydrolytic N,rapidly available P,rapidly available K,available Zn,available B and water-soluble Cl-were increased.展开更多
Piperacillin is a polar organic substance,and can reduce the interfacial tension of oil and water when dissolved in water.In this study,changes in dichloromethane–water interfacial tensions and microdroplet sizes dur...Piperacillin is a polar organic substance,and can reduce the interfacial tension of oil and water when dissolved in water.In this study,changes in dichloromethane–water interfacial tensions and microdroplet sizes during piperacillin synthesis from an aqueous solution of ampicillin and dichloromethane solution of 4-ethyl-2,3-dioxo-1-piperazine carbonyl chloride(EDPC)were observed using a pendent drop technique and a coaxial ring tube system with embedded high-speed camera,respectively.It was found that the rapid N-acylation reaction caused the piperacillin at the interface to synthesize rapidly and diffuse out slowly,resulting in the interfacial tension decreased from 19.5 m N·m-1 to 7.2 m N·m-1 rapidly and then increased slowly as the concentrations of ampicillin and EDPC were 0.05 mol·L-1 and 0.1 mol·L-1.Meanwhile,the increase in the concentration of EDPC increased the peak concentration of piperacillin at the interface,and the addition of ethyl acetate to the ampicillin solution promoted mass transfer and reduced the aggregation of piperacillin effectively.During synthesis,the interfacial tension decreased,leading to a change in droplet sizes in the micro-reaction system.The two-phase reaction was carried out in a coaxial ring tube,with ampicillin and EDPC solutions as continuous and dispersed phases,respectively.The reaction reduced the dripping flow area,and the addition of ethyl acetate to the ampicillin solution slightly affected the division of the flow pattern.Under the same flow conditions,the droplet sizes of the reaction group were smaller than those of the no reaction group.The experimental results demonstrated that the increase of the continuous phase,decrease in the dispersed phase flow rate,or increase in EDPC concentration making droplet sizes smaller,and the addition of ethyl acetate slightly affected droplet sizes.These findings are important for the design and optimization of piperacillin synthesis reactors.展开更多
Ginkgo biloba L. is a precious relic tree species with important economic value. Seeds, as a vital reproductive organ of plants, can be used to distinguish cultivars of the species. We chose 400 seeds from two cultiva...Ginkgo biloba L. is a precious relic tree species with important economic value. Seeds, as a vital reproductive organ of plants, can be used to distinguish cultivars of the species. We chose 400 seeds from two cultivars of ginkgo(“Fozhi” and “Maling”;200 seeds for each cultivar) as the study material and used the Gielis equation to fit the projected shape of these seeds. The coefficients of variation(CV) in root mean squared errors(RMSE)obtained from the fitted data were used to compare the level of inter-cultivar variations in seed shape. We also used the covariance analysis to compare the allometric relationships between seed weights and projected areas of these two cultivars. The Gielis equation fitted well the seedshapes of two ginkgo cultivars. The lower CV in RMSE of cultivar “Fozhi” than “Maling” indicated a less symmetrical seed shape in the latter than the former. The bootstrap percentile method showed that the seed shape differences between the two cultivars were significant. However, there was no significant difference in the exponents between the seed weights and the projected areas of these two cultivars.Overall, the significant differences in shapes between the seeds of two ginkgo cultivars were well explained by the Gielis equation;this model can be further extended to compare morphological differences in other ginkgo cultivars, and even for plant seeds or animal eggs that have similar oval shapes.展开更多
A mathematical model is developed for the calculation of the nucleation and growth process of silica nanostructured particles prepared by using the drop-by-drop method,and the calculation results of the proposed model...A mathematical model is developed for the calculation of the nucleation and growth process of silica nanostructured particles prepared by using the drop-by-drop method,and the calculation results of the proposed model is compared with the experimental value obtained from SAXS data.The model provides a non-ideal improvement in the supersaturation calculation and considers the impact of both mass transfer and surface reaction on the particle growth rate.The nucleation and growth rates are coupled depending on the change in monomer concentration over time,based on which the particle size and distribution are calculated.The growth curve of the silica particles from 3 nm to 20 nm and the change in particle number from 0 to over 10^(20) are calculated,which are consistent with the experimental values,establishing the reliability of the model.The calculations of the growth rate reveal that mass transfer controls the growth of silica particles before 10 min and the surface reaction is the rate-determining step after 10 min.The changes in the model parameters obtained by fitting with the SAXS data under different reaction conditions indicate the sensitivity of the corresponding process to different conditions.Moreover,the relationship between the particle growth rate and monomer concentration change is analyzed using the proposed model.展开更多
Quinones have been widely studied as a potential catholyte in water-based redox flow batteries(RFBs)due to their ability to carry both electrons and protons in aqueous solutions.The wide variety of quinones and deriva...Quinones have been widely studied as a potential catholyte in water-based redox flow batteries(RFBs)due to their ability to carry both electrons and protons in aqueous solutions.The wide variety of quinones and derivatives offers exciting opportunities to optimize the device performance while poses theoretical challenges to quantify their electrochemical behavior as required for molecular design.Computational screening of target quinones with high performance is far from satisfactory.While solvation of quinones affects their potential application in RFBs in terms of both electrochemical windows,stability,and charge transport,experimental data for the solvation structure and solvation free energies are rarely available if not incomplete.Besides,conventional thermodynamic models are mostly unreliable to estimate the properties of direct interest for electrochemical applications.Here,we analyze the hydration free energies of more than 1,400 quinones by combining the first-principles calculations and the classical density functional theory.In order to attain chemical insights and possible trends,special attention is placed on the effects of"backbones"and functional groups on the solvation behavior.The theoretical results provide a thermodynamic basis for the design,synthesis,and screening of high-performance catholytes for electrical energy storage.展开更多
The establishment of ecological risk thresholds for arsenic(As)plays a pivotal role in developing soil conservation strategies.However,despite many studies regarding the toxicological profile of As,such thresholds var...The establishment of ecological risk thresholds for arsenic(As)plays a pivotal role in developing soil conservation strategies.However,despite many studies regarding the toxicological profile of As,such thresholds varying by diverse soil properties have rarely been established.This study aims to address this gap by compiling and critically examining an extensive dataset of As toxicity data sourced from existing literature.Furthermore,to augment the existing information,experimental studies on As toxicity focusing on barley-root elongation were carried out across various soil types.The As concentrations varied from 12.01 to 437.25 mg/kg for the effective concentrations that inhibited 10%of barley-root growth(EC10).The present study applied a machine-learning approach to investigate the complex associations between the toxicity thresholds of As and diverse soil properties.The results revealed that Mn-/Fe-ox and clay content emerged as the most influential factors in predicting the EC10 contribution.Additionally,by using a species sensitivity distribution model and toxicity data from 21 different species,the hazardous concentration for x%of species(HCx)was calculated for four representative soil scenarios.The HC5 values for acidic,neutral,alkaline,and alkaline calcareous soils were 80,47,40,and 28 mg/kg,respectively.This study establishes an evidence-based methodology for deriving soil-specific guidance concerning As toxicity thresholds.展开更多
As a bioproduct from the thermal decomposition of biomass,biochar has various applications in diversified field.In this study,a bibliometric analysis was conducted to visualize the current research status and trends o...As a bioproduct from the thermal decomposition of biomass,biochar has various applications in diversified field.In this study,a bibliometric analysis was conducted to visualize the current research status and trends of biochar research.A total of 5535 documents were collected from the Web of Science Core Collection and subjected to visualization analysis for the biochar field’s development in 2021 with CiteSpace software.The visual analysis results demonstrate that the number of publications expanded dramatically in 2021,and the growth trend would continue.China and USA were the most contributing countries in biochar research in terms of the number of publications.Based on the keyword co-occurrence analyses,“Biochar for toxic metal immobilization”,“Biochar-based catalyst for biofuel production”,“Biochar for global climate change mitigation”,“Biochar for salinity and drought stress amelioration”,“Biochar amendment in composting”,and“Biochar as additives in anaerobic digestion”were the main research trends and hotspots in this field in 2021.This indicates that the biochar research was multidisciplinary.Regarding the research hotspots,the employment of biochar as heterogeneous catalysts for biofuel production gained great attention in 2021.On the contrary,bioremediation using functional bacteria immobilized on biochar and biochar-assisted advanced oxidation process were well-studied but with less frequency than other topics in 2021.Furthermore,the future research was proposed for green and sustainable applications of biochar.This review provides a comprehensive overview of the research frontiers,the evolution of research hotspots,and potential future research directions in the biochar field.展开更多
Long-chainα-olefins have a high added value as important raw materials for many highly marketable products.Fishcher-Tropsch synthesis products contain ultrahigh-contentα-olefins,which are of great value if the chall...Long-chainα-olefins have a high added value as important raw materials for many highly marketable products.Fishcher-Tropsch synthesis products contain ultrahigh-contentα-olefins,which are of great value if the challenging separation ofα-olefin/paraffin is achieved through energy-saving ways,for which adsorption separation is an attractive technology.One of the most significant differences between the adsorption separation of long-chain and light hydrocarbons is the steric hindrance of the molecular chain.Herein,we propose a combination of window size,metal node spacing,and bending degree to quantitatively describe the adsorption cavity structure for the separation of long-chainα-olefin/paraffin.The general cavity structural characteristics of microporous materials with good separation performance for long-chainα-olefin/paraffin are revealed.The selective adsorption of liquid C6 and C_(8)α-olefin/paraffin mixtures on CuBTC(BTC=benzene-1,3,5-tricarboxylate)was studied in detail to reveal the influence of the cavity structure on the adsorption and interaction using a combination of batch adsorption experiments and molecular simulation techniques.CuBTC exhibited 360 and 366 mg/g olefin adsorption capacities for C6 and C8 linearα-olefins,respectively.The adsorption energies were−0.540 and−0.338 eV for C8 linearα-olefin and paraffin,respectively.The contributions of different types of interactions to the overall adsorption energy were quantified to illustrate the adsorption energy difference betweenα-olefin/paraffin and CuBTC.This work provides a new understanding of the long-chain hydrocarbon adsorption behavior different from ethylene/ethane and propylene/propane,which guides the design of adsorbents forα-olefin/paraffin separation.展开更多
The liquid products of Fischer–Tropsch synthesis with a high content of linearα-olefins can act as valuable raw materials for increasing high added-valueα-olefin production if the challenging separation of long-ch...The liquid products of Fischer–Tropsch synthesis with a high content of linearα-olefins can act as valuable raw materials for increasing high added-valueα-olefin production if the challenging separation of long-chainα-olefin/paraffin is achieved.Adsorption separation is an efficient alternative to energy-intensive distillation.Herein,the selective adsorption behavior and interaction mechanism of liquidα-olefin/paraffin on Mg metal–organic framework(MOF)-74 were investigated using a combination of batch adsorption experiments and molecular simulation techniques.Mg-MOF-74 exhibited 301 and 333 mg/g olefin adsorption capacities for C6 and C8 linearα-olefins in binary olefin/paraffin mixtures,respectively,and was still unsaturated at high olefin concentrations.The adsorption isotherms were analyzed and compared with the simulated results by configurational-bias grand canonical Monte Carlo(CB-GCMC)simulation.The visualized adsorption sites by CB-GCMC simulation indicated that all adsorbates were arranged in hexagonal shapes and preferentially adsorbed by the vertex of the hexagon,where the metal node magnesium is located.The adsorption energies were−1.456 and−0.378 eV for C8 linearα-olefin and paraffin,respectively,calculated by density functional theory simulation based on the visualized adsorption sites.The charge transfer was analyzed,and the contributions of different kinds of interactions to the overall adsorption energy were quantified by principle orbital interaction analysis to further reveal the difference in adsorption energy betweenα-olefin/paraffin and Mg-MOF-74.This work also provides a general means to investigate the liquid adsorption performance and host–guest interactions in the adsorption or catalytic processes of nanoporous materials.展开更多
Numerous studies have unequivocally demonstrated that biochar and,to a lesser degree,earthworms can independently improve soil fertility and crop productivity,although information about their co-application effects on...Numerous studies have unequivocally demonstrated that biochar and,to a lesser degree,earthworms can independently improve soil fertility and crop productivity,although information about their co-application effects on soil characteristics is limited.In this review,(1)earthworm biomarkers and underlying influencing factors,as well as the changes in the amended soil quality in response to co-application of earthworms and biochar are presented,(2)the functional interactions between earthworms and biochar in soil are summarized;(3)the principles governing the synergetic effects of biochar and earthworms on soil quality enhancement are probed;and(4)alternative strategies to optimize the efficacy of earthworm and biochar amendments are provided.It is noteworthy that while low doses of biochar can have a positive effect on various earthworm biomarkers,including growth and reproduction,restoration of the intestinal environment,and the mitigation of cellular organelle toxicity and genetic damage,high biochar dosages can yield adverse effects.Conversely,earthworms play a crucial role in distributing biochar particles deeper into the soil matrix,bolstering carbon sequestration potential,and enhancing the persistence and efficiency of biochar utilization.Moreover,earthworms stimulate the production of soil extracellular enzymes by microorganisms,which are pivotal to the processing,stabilization,and decomposition of soil organic matter,as well as nutrient cycling in terrestrial ecosystems.Additionally,they enhance the binding affinities of these enzymes to biochar.Significantly,changes in earthworm biomarkers in response to biochar integration are predominately governed by biochar properties and dosage,contact time,and soil type.展开更多
Biogas slurry is not suitable for liquid fertilizer due to its high amounts of volatile materials being of complicated composition and peculiar smell. In order to remove volatiles from biogas slurry efficiently, the d...Biogas slurry is not suitable for liquid fertilizer due to its high amounts of volatile materials being of complicated composition and peculiar smell. In order to remove volatiles from biogas slurry efficiently, the dynamic headspace and gas chromatography-mass spectrometry were used to clear the composition of volatiles. Nitrogen stripping and superfluous ozone were also used to remove volatiles from biogas slurry. The results showed that there were 21 kinds of volatile compounds in the biogas slurry, including sulfur compounds, organic amines, benzene, halogen generation of hydrocarbons and alkanes, some of which had strong peculiar smell. The volatile compounds in biogas slurry can be removed with the rate of 53.0% by nitrogen stripping and with rate of 81.7% by the oxidization and stripping of the superfluous ozone. On this basis, the removal rate of the volatile compounds reached 99.2% by chloroform and n-hexane extraction, and almost all of odor was eliminated. The contents of some dissolved organic compounds decreased obviously and however main plant nutrients had no significant change in the biogas slurry after being treated.展开更多
Microfluidic systems provide a powerful platform for preparing,functionalizing,and manipulating nano-/micro-materials.In this review,we summarize the characteristics of state-of-the-art microfluidic techniques and the...Microfluidic systems provide a powerful platform for preparing,functionalizing,and manipulating nano-/micro-materials.In this review,we summarize the characteristics of state-of-the-art microfluidic techniques and their application to processing novel nano-/micro-materials with tunable size,shape,morphology,composition,and properties.A variety of synthesis strategies based on novel microfiuidic devices are presented and compared,including their integration with real-time monitoring,external fields,and automatic feedback control.Novel functional nano-/micro-materials with complex structures have been controllably prepared and post-processed to obtain high-quality products.Strategies for controlling and tuning physical and chemical properties are also examined in terms of the design and function of microfluidic platforms.We provide an outlook on future developments in the processing of nano-/micro-materials by microfluidic technologies.展开更多
Biochar is the carbon-rich product obtained from the thermochemical conversion of biomass under oxygen-limited conditions.Biochar has attained extensive attention due to its agronomical and environmental benefits in a...Biochar is the carbon-rich product obtained from the thermochemical conversion of biomass under oxygen-limited conditions.Biochar has attained extensive attention due to its agronomical and environmental benefits in agro-ecosystems.This work adopts the scientometric analysis method to assess the development trends of biochar research based on the literature data retrieved from the Web of Science over the period of 1998-2018.By analysing the basic characteristics of 6934 publications,we found that the number of publications grew rapidly since 2010.Based on a keyword analysis,it is concluded that scholars have had a fundamental recognition of biochar and preliminarily found that biochar application had agronomic and environmental benefits during the period of 1998-2010.The clustering results of keywords in documents published during 2011-2015 showed that the main research hotspots were“biochar production”,“biochar and global climate change”,“soil quality and plant growth”,“organic pollutants removal”,and“heavy metals immobilization”.While in 2016-2018,beside these five main research hotspots,“biochar and composting”topic had also received greater attention,indicating that biochar utilization in organic solid waste composting is the current research hotspot.Moreover,updated reactors(e.g.,microwave reactor,fixed-bed reactor,screw-feeding reactor,bubbling fluidized bed reactor,etc.)or technologies(e.g.,solar pyrolysis,Thermo-Catalytic Reforming process,liquefaction technology,etc.)applied for efficient energy production and modified biochar for environmental remediation have been extensively studied recently.The findings may help the new researchers to seize the research frontier in the biochar field.展开更多
Transformation of polychlorinated biphenyls (PCBs) by zero-valent iron represents one of the latest innovative technologies for environmental remediation. The dechlorination of 4-chlorobiphenyl (4-C1BP) by nanosca...Transformation of polychlorinated biphenyls (PCBs) by zero-valent iron represents one of the latest innovative technologies for environmental remediation. The dechlorination of 4-chlorobiphenyl (4-C1BP) by nanoscale zero-valent iron (NZVI) in the presence of humic acid or metal ions was investigated. The results showed that the dechlorination of 4-C1BP by NZVI increased with decreased solution pH. When the initial pH value was 4.0, 5.5, 6.8, and 9.0, the de.chlorination efficiencies of 4-CIBP after 48 hr were 53.8%, 47.8%, 35.7%, and 35.6%, respectively. The presence of humic acid inhibited the reduction of 4-CIBP in the first 4 hi', and then significantly accelerated the dechlorination by reaching 86.3% in 48 hr. Divalent metal ions, Co2+, Cu2+, and Ni2+, were reduced and formed bimetals with NZVI, thereby enhanced the dechlorination of 4-CIBP. The dechlorination percentages of 4-CIBP in the presence of 0.1 mmol/L Co2~, Cuz~ and Niz~ were 66.1%, 66.0% and 64.6% in 48 hr, and then increased to 67.9%, 71.3% and 73.5%, after 96 hr respectively. The dechlorination kinetics of 4-C1BP by the NZVI in all cases followed pseudo-first order model. The results provide a basis for better understanding of the dechlorination mechanisms of PCBs in real environment.展开更多
In this paper,we present a new method for preparing γ-alumina nanoparticles with a bimodal pore size distribution by using an efficiently mixing membrane dispersion microreactor.NH4HCO3and AI2(SO4)3.18H2Owere reacted...In this paper,we present a new method for preparing γ-alumina nanoparticles with a bimodal pore size distribution by using an efficiently mixing membrane dispersion microreactor.NH4HCO3and AI2(SO4)3.18H2Owere reacted under vigorous mixing to give an ammonium aluminum carbonate hydroxide (AACH)precursor.γ-Alumina was obtained by calcination of AACH at 550℃ for 6h.The effects of NH4HCO3concentration,pH during aging,and reaction temperature were investigated.The mechanism of bimodal pore formation was clarified.The results showed that large pores (10-100nm) were mainly formed in the reactor and during aging,and small pores (0-10nm)were mainly formed during calcination.When the concentration of NH4HCO3was 1.5mol/L,the aging pH was 9.2,and the reaction temperature was 80℃,γ-alumina with a specific surface area of 504.7m^2/g and pore volume of 1.76mL/g was obtained.The average size of the large pores was about 30nm,and the average size of the small pores was about 4nm.展开更多
Biochar,derived from thermal pyrolysis of biomass,has been regarded as a low-cost,sustainable and beneficial material and widely applied in agriculture,environment and energy during the last two decades.To elucidate t...Biochar,derived from thermal pyrolysis of biomass,has been regarded as a low-cost,sustainable and beneficial material and widely applied in agriculture,environment and energy during the last two decades.To elucidate the research status timely and future trends in biochar field,CiteSpace is used to systematically analyze the related literature retrieved from the Web of Science core collection in 2019.Based on the keywords clustering analysis,it was found that“biochar production”,“organic pollutants removal”,“heavy metals immobilization”,“bioremediation”were the main hotspots in research covering biochar.“Bioremediation”is an emerging topic and deserves extensive attention due to its highly effective and environmentally friendly treatment of pollutants.Improving the phytoremediation effect,immobilizing functional microorganisms on biochar,and using microorganisms as raw materials to produce biochar were the common methods of biochar-assisted bioremediation.While studies focused on“soil quality and plant growth”and“biochar and global climate change”decreased,investigations concentrated in the toxicity of biochar to soil biota and ruminants are sustainably growing.Research on direct and catalytic thermal pyrolysis of green waste(mainly microalgae)for biofuels(bio-oil,biodiesel,syngas,etc.)and biochar production is increasing.Converting municipal wastes(e.g.,sewage sludge,fallen leaves)into biochar through pyrolysis was a suitable treatment for municipal waste and became a popular topic in recent time.Moreover,the biochar produced from these municipal wastes exhibited excellent performance in the removal of pollutants from wastewater and soil.This review may help to identify future directions in biochar research and applications.展开更多
基金supported by grants from National Key R&D Program of China,No.2023YFC2506100(to JZ)the National Natural Science Foundation of China,No.82171062(to JZ).
文摘Subretinal fibrosis is the end-stage sequelae of neovascular age-related macular degeneration.It causes local damage to photoreceptors,retinal pigment epithelium,and choroidal vessels,which leads to permanent central vision loss of patients with neovascular age-related macular degeneration.The pathogenesis of subretinal fibrosis is complex,and the underlying mechanisms are largely unknown.Therefore,there are no effective treatment options.A thorough understanding of the pathogenesis of subretinal fibrosis and its related mechanisms is important to elucidate its complications and explore potential treatments.The current article reviews several aspects of subretinal fibrosis,including the current understanding on the relationship between neovascular age-related macular degeneration and subretinal fibrosis;multimodal imaging techniques for subretinal fibrosis;animal models for studying subretinal fibrosis;cellular and non-cellular constituents of subretinal fibrosis;pathophysiological mechanisms involved in subretinal fibrosis,such as aging,infiltration of macrophages,different sources of mesenchymal transition to myofibroblast,and activation of complement system and immune cells;and several key molecules and signaling pathways participating in the pathogenesis of subretinal fibrosis,such as vascular endothelial growth factor,connective tissue growth factor,fibroblast growth factor 2,platelet-derived growth factor and platelet-derived growth factor receptor-β,transforming growth factor-βsignaling pathway,Wnt signaling pathway,and the axis of heat shock protein 70-Toll-like receptors 2/4-interleukin-10.This review will improve the understanding of the pathogenesis of subretinal fibrosis,allow the discovery of molecular targets,and explore potential treatments for the management of subretinal fibrosis.
基金supported by the National Natural Science Foundation of China(U23A20573,U23A20140,22109038)the Starting Research Funds of Hebei University of Science and Technology,Hebei Natural Science Foundation(D2022208001)+1 种基金the S&T Program of Hebei(23314401D)Hebei Pharmaceutical and Chemical Technology Innovation Center(225676121H).
文摘Green hydrogen from electrolysis of water has attracted widespread attention as a renewable power source.Among several hydrogen production methods,it has become the most promising technology.However,there is no large-scale renewable hydrogen production system currently that can compete with conventional fossil fuel hydrogen production.Renewable energy electrocatalytic water splitting is an ideal production technology with environmental cleanliness protection and good hydrogen purity,which meet the requirements of future development.This review summarizes and introduces the current status of hydrogen production by water splitting from three aspects:electricity,catalyst and electrolyte.In particular,the present situation and the latest progress of the key sources of power,catalytic materials and electrolyzers for electrocatalytic water splitting are introduced.Finally,the problems of hydrogen generation from electrolytic water splitting and directions of next-generation green hydrogen in the future are discussed and outlooked.It is expected that this review will have an important impact on the field of hydrogen production from water.
基金supported by the National Natural Science Foundation of China(Grant Nos.U2242206,42175015,and 41975094)the Basic Research and Operational Special Project of CAMS(Grant No.2021Z007).
文摘Seamless prediction is a weather-climate integrated prediction covering multiple time scales that include days,weeks,months,seasons,years,and decades.Seamless prediction can provide different industries with information such as weather conditions and climate variations from the next few days to years,which have important impacts on economic and social development and important reference value for short-,medium-and long-term decision-making and planning of the country.Therefore,seamless prediction has received widespread attention from the international scientific community recently.As Chinese scientists have also carried out relevant research,this paper reviews the research in China on developments and applications of seamless prediction methods and prediction systems in recent years.Among them,the main progress of seamless prediction methods studies is reviewed from four aspects:short-and medium-range weather forecasting,subseasonal-to-seasonal,seasonal-to-interannual,and decadal climate prediction.In terms of development and application of seamless prediction systems,the main achievements made by meteorological operational departments,scientific institutes,and universities in China in recent years are reviewed.Finally,some of the issues in seamless prediction that need further study are discussed.
基金Supported by National Natural Science Foundation of China(Grant Nos.52072161,U20A20331)China Postdoctoral Science Foundation(Grant No.2019T120398)+2 种基金State Key Laboratory of Automotive Safety and Energy of China(Grant No.KF2016)Vehicle Measurement Control and Safety Key Laboratory of Sichuan Province(Grant No.QCCK2019-002)Young Elite Scientists Sponsorship Program by CAST(Grant No.2018QNRC 001).
文摘Due to the bus characteristics of large quality,high center of gravity and narrow wheelbase,the research of its yaw stability control(YSC)system has become the focus in the field of vehicle system dynamics.However,the tire nonlinear mechanical properties and the effectiveness of the YSC control system are not considered carefully in the current research.In this paper,a novel adaptive nonsingular fast terminal sliding mode(ANFTSM)control scheme for YSC is proposed to improve the bus curve driving stability and safety on slippery roads.Firstly,the STI(Systems Technologies Inc.)tire model,which can effectively reflect the nonlinear coupling relationship between the tire longitudinal force and lateral force,is established based on experimental data and firstly adopted in the bus YSC system design.On this basis,a more accurate bus lateral dynamics model is built and a novel YSC strategy based on ANFTSM,which has the merits of fast transient response,finite time convergence and high robustness against uncertainties and external disturbances,is designed.Thirdly,to solve the optimal allocation problem of the tire forces,whose objective is to achieve the desired direct yaw moment through the effective distribution of the brake force of each tire,the robust least-squares allocation method is adopted.To verify the feasibility,effectiveness and practicality of the proposed bus YSC approach,the TruckSim-Simulink co-simulation results are finally provided.The co-simulation results show that the lateral stability of bus under special driving conditions has been significantly improved.This research proposes a more effective design method for bus YSC system based on a more accurate tire model.
基金Supported by Fund of Hongyun Honghe Tobacco(Group)Co.Ltd.(HYHH2012YL03)Fund of Yunnan Branch of China National Tobacco Corporation(2010YN25)
文摘[Objective]This study was conducted to evaluate the soil fertility in Yiliantobacco-growing areas of Hunan Province.[Method]The soil nutrient contents iseven tobacco-growing towns of Yiliang County,Yunnan Province were surveyefrom 2010 to 2013 and integrated soil fertility index(SFI value)was calculated tanalyze the soil fertility suitability in theses areas.[Result]The soil p H,contents oorganic matter,hydrolytic N,rapidly available K and available B were all at an appropriate level,while the contents of rapidly available P,available Mg,available Zand water-soluble Cl-were high.Among them,the contents of available P and water-soluble Cl-had great variation.Finally,the soil fertility suitability of Yiliang tobacco-growing areas was graded based on their SFI values.As a result,20%of thestobacco-growing areas were in Grade I,47.7%in Grade II,29.3%in Grade III1.5%in Grade IV and 1.5%in Grade V.The average SFI was 0.61.From 2010 t2013,the p H value and available Mg content reduced year by year,while the contents of organic matter,hydrolytic N,rapidly available P,rapidly available K,available Zn,available B and water-soluble Cl-were increased.
基金financially supported by the National Key Research and Development Program of China(2019YFA0905100)the National Natural Science Foundation of China(21878169 and 21991102)Tsinghua University Initiative Scientific Research Program(2018Z05JZY010)。
文摘Piperacillin is a polar organic substance,and can reduce the interfacial tension of oil and water when dissolved in water.In this study,changes in dichloromethane–water interfacial tensions and microdroplet sizes during piperacillin synthesis from an aqueous solution of ampicillin and dichloromethane solution of 4-ethyl-2,3-dioxo-1-piperazine carbonyl chloride(EDPC)were observed using a pendent drop technique and a coaxial ring tube system with embedded high-speed camera,respectively.It was found that the rapid N-acylation reaction caused the piperacillin at the interface to synthesize rapidly and diffuse out slowly,resulting in the interfacial tension decreased from 19.5 m N·m-1 to 7.2 m N·m-1 rapidly and then increased slowly as the concentrations of ampicillin and EDPC were 0.05 mol·L-1 and 0.1 mol·L-1.Meanwhile,the increase in the concentration of EDPC increased the peak concentration of piperacillin at the interface,and the addition of ethyl acetate to the ampicillin solution promoted mass transfer and reduced the aggregation of piperacillin effectively.During synthesis,the interfacial tension decreased,leading to a change in droplet sizes in the micro-reaction system.The two-phase reaction was carried out in a coaxial ring tube,with ampicillin and EDPC solutions as continuous and dispersed phases,respectively.The reaction reduced the dripping flow area,and the addition of ethyl acetate to the ampicillin solution slightly affected the division of the flow pattern.Under the same flow conditions,the droplet sizes of the reaction group were smaller than those of the no reaction group.The experimental results demonstrated that the increase of the continuous phase,decrease in the dispersed phase flow rate,or increase in EDPC concentration making droplet sizes smaller,and the addition of ethyl acetate slightly affected droplet sizes.These findings are important for the design and optimization of piperacillin synthesis reactors.
基金supported by the National Natural Science Foundation of China(No.31400348)Postgraduate Research and Practice Innovation Program of Jiangsu Province(No.KYCX17_0836)the PAPD of Jiangsu Province。
文摘Ginkgo biloba L. is a precious relic tree species with important economic value. Seeds, as a vital reproductive organ of plants, can be used to distinguish cultivars of the species. We chose 400 seeds from two cultivars of ginkgo(“Fozhi” and “Maling”;200 seeds for each cultivar) as the study material and used the Gielis equation to fit the projected shape of these seeds. The coefficients of variation(CV) in root mean squared errors(RMSE)obtained from the fitted data were used to compare the level of inter-cultivar variations in seed shape. We also used the covariance analysis to compare the allometric relationships between seed weights and projected areas of these two cultivars. The Gielis equation fitted well the seedshapes of two ginkgo cultivars. The lower CV in RMSE of cultivar “Fozhi” than “Maling” indicated a less symmetrical seed shape in the latter than the former. The bootstrap percentile method showed that the seed shape differences between the two cultivars were significant. However, there was no significant difference in the exponents between the seed weights and the projected areas of these two cultivars.Overall, the significant differences in shapes between the seeds of two ginkgo cultivars were well explained by the Gielis equation;this model can be further extended to compare morphological differences in other ginkgo cultivars, and even for plant seeds or animal eggs that have similar oval shapes.
基金financially supported by the National Natural Science Foundation of China(21878169,21991102)the National Key Research and Development Program of China(2019YFA0905100)the Tsinghua University Initiative Scientific Research Program(2018Z05JZY010)。
文摘A mathematical model is developed for the calculation of the nucleation and growth process of silica nanostructured particles prepared by using the drop-by-drop method,and the calculation results of the proposed model is compared with the experimental value obtained from SAXS data.The model provides a non-ideal improvement in the supersaturation calculation and considers the impact of both mass transfer and surface reaction on the particle growth rate.The nucleation and growth rates are coupled depending on the change in monomer concentration over time,based on which the particle size and distribution are calculated.The growth curve of the silica particles from 3 nm to 20 nm and the change in particle number from 0 to over 10^(20) are calculated,which are consistent with the experimental values,establishing the reliability of the model.The calculations of the growth rate reveal that mass transfer controls the growth of silica particles before 10 min and the surface reaction is the rate-determining step after 10 min.The changes in the model parameters obtained by fitting with the SAXS data under different reaction conditions indicate the sensitivity of the corresponding process to different conditions.Moreover,the relationship between the particle growth rate and monomer concentration change is analyzed using the proposed model.
基金supported by the National Natural Science Foundation of China(U1862204)the U.S.National Science Foundation(NSF-1940118)。
文摘Quinones have been widely studied as a potential catholyte in water-based redox flow batteries(RFBs)due to their ability to carry both electrons and protons in aqueous solutions.The wide variety of quinones and derivatives offers exciting opportunities to optimize the device performance while poses theoretical challenges to quantify their electrochemical behavior as required for molecular design.Computational screening of target quinones with high performance is far from satisfactory.While solvation of quinones affects their potential application in RFBs in terms of both electrochemical windows,stability,and charge transport,experimental data for the solvation structure and solvation free energies are rarely available if not incomplete.Besides,conventional thermodynamic models are mostly unreliable to estimate the properties of direct interest for electrochemical applications.Here,we analyze the hydration free energies of more than 1,400 quinones by combining the first-principles calculations and the classical density functional theory.In order to attain chemical insights and possible trends,special attention is placed on the effects of"backbones"and functional groups on the solvation behavior.The theoretical results provide a thermodynamic basis for the design,synthesis,and screening of high-performance catholytes for electrical energy storage.
基金supported by the National Key R&D Programof China(2021YFC1809102)the National Natural Science Foundation of China(42225701,42107041,41977027)the Natural Science Foundation of Jiangsu Province,China(BK20210997).
文摘The establishment of ecological risk thresholds for arsenic(As)plays a pivotal role in developing soil conservation strategies.However,despite many studies regarding the toxicological profile of As,such thresholds varying by diverse soil properties have rarely been established.This study aims to address this gap by compiling and critically examining an extensive dataset of As toxicity data sourced from existing literature.Furthermore,to augment the existing information,experimental studies on As toxicity focusing on barley-root elongation were carried out across various soil types.The As concentrations varied from 12.01 to 437.25 mg/kg for the effective concentrations that inhibited 10%of barley-root growth(EC10).The present study applied a machine-learning approach to investigate the complex associations between the toxicity thresholds of As and diverse soil properties.The results revealed that Mn-/Fe-ox and clay content emerged as the most influential factors in predicting the EC10 contribution.Additionally,by using a species sensitivity distribution model and toxicity data from 21 different species,the hazardous concentration for x%of species(HCx)was calculated for four representative soil scenarios.The HC5 values for acidic,neutral,alkaline,and alkaline calcareous soils were 80,47,40,and 28 mg/kg,respectively.This study establishes an evidence-based methodology for deriving soil-specific guidance concerning As toxicity thresholds.
基金National Natural Science Foundation of China(Project No.42225701,42007355).
文摘As a bioproduct from the thermal decomposition of biomass,biochar has various applications in diversified field.In this study,a bibliometric analysis was conducted to visualize the current research status and trends of biochar research.A total of 5535 documents were collected from the Web of Science Core Collection and subjected to visualization analysis for the biochar field’s development in 2021 with CiteSpace software.The visual analysis results demonstrate that the number of publications expanded dramatically in 2021,and the growth trend would continue.China and USA were the most contributing countries in biochar research in terms of the number of publications.Based on the keyword co-occurrence analyses,“Biochar for toxic metal immobilization”,“Biochar-based catalyst for biofuel production”,“Biochar for global climate change mitigation”,“Biochar for salinity and drought stress amelioration”,“Biochar amendment in composting”,and“Biochar as additives in anaerobic digestion”were the main research trends and hotspots in this field in 2021.This indicates that the biochar research was multidisciplinary.Regarding the research hotspots,the employment of biochar as heterogeneous catalysts for biofuel production gained great attention in 2021.On the contrary,bioremediation using functional bacteria immobilized on biochar and biochar-assisted advanced oxidation process were well-studied but with less frequency than other topics in 2021.Furthermore,the future research was proposed for green and sustainable applications of biochar.This review provides a comprehensive overview of the research frontiers,the evolution of research hotspots,and potential future research directions in the biochar field.
基金supported by the National Natural Science Foundation of China(Nos.21878169 and 21991102)the National Key Research and Development Program of China(No.2019YFA0905100)the Tsinghua University Initiative Scientific Research Program(No.2018Z05JZY010).
文摘Long-chainα-olefins have a high added value as important raw materials for many highly marketable products.Fishcher-Tropsch synthesis products contain ultrahigh-contentα-olefins,which are of great value if the challenging separation ofα-olefin/paraffin is achieved through energy-saving ways,for which adsorption separation is an attractive technology.One of the most significant differences between the adsorption separation of long-chain and light hydrocarbons is the steric hindrance of the molecular chain.Herein,we propose a combination of window size,metal node spacing,and bending degree to quantitatively describe the adsorption cavity structure for the separation of long-chainα-olefin/paraffin.The general cavity structural characteristics of microporous materials with good separation performance for long-chainα-olefin/paraffin are revealed.The selective adsorption of liquid C6 and C_(8)α-olefin/paraffin mixtures on CuBTC(BTC=benzene-1,3,5-tricarboxylate)was studied in detail to reveal the influence of the cavity structure on the adsorption and interaction using a combination of batch adsorption experiments and molecular simulation techniques.CuBTC exhibited 360 and 366 mg/g olefin adsorption capacities for C6 and C8 linearα-olefins,respectively.The adsorption energies were−0.540 and−0.338 eV for C8 linearα-olefin and paraffin,respectively.The contributions of different types of interactions to the overall adsorption energy were quantified to illustrate the adsorption energy difference betweenα-olefin/paraffin and CuBTC.This work provides a new understanding of the long-chain hydrocarbon adsorption behavior different from ethylene/ethane and propylene/propane,which guides the design of adsorbents forα-olefin/paraffin separation.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21878169 and 21991102)Key Technologies Research and Development Program of China(No.2019YFA0905100)Tsinghua University Initiative Scientific Research Program(No.2018Z05JZY010).
文摘The liquid products of Fischer–Tropsch synthesis with a high content of linearα-olefins can act as valuable raw materials for increasing high added-valueα-olefin production if the challenging separation of long-chainα-olefin/paraffin is achieved.Adsorption separation is an efficient alternative to energy-intensive distillation.Herein,the selective adsorption behavior and interaction mechanism of liquidα-olefin/paraffin on Mg metal–organic framework(MOF)-74 were investigated using a combination of batch adsorption experiments and molecular simulation techniques.Mg-MOF-74 exhibited 301 and 333 mg/g olefin adsorption capacities for C6 and C8 linearα-olefins in binary olefin/paraffin mixtures,respectively,and was still unsaturated at high olefin concentrations.The adsorption isotherms were analyzed and compared with the simulated results by configurational-bias grand canonical Monte Carlo(CB-GCMC)simulation.The visualized adsorption sites by CB-GCMC simulation indicated that all adsorbates were arranged in hexagonal shapes and preferentially adsorbed by the vertex of the hexagon,where the metal node magnesium is located.The adsorption energies were−1.456 and−0.378 eV for C8 linearα-olefin and paraffin,respectively,calculated by density functional theory simulation based on the visualized adsorption sites.The charge transfer was analyzed,and the contributions of different kinds of interactions to the overall adsorption energy were quantified by principle orbital interaction analysis to further reveal the difference in adsorption energy betweenα-olefin/paraffin and Mg-MOF-74.This work also provides a general means to investigate the liquid adsorption performance and host–guest interactions in the adsorption or catalytic processes of nanoporous materials.
基金National Key Agricultural Science and Technology Project of China(NK2022180104)National Key Research and Development Program of China(2021YFD1500202,2019YFC1803403).
文摘Numerous studies have unequivocally demonstrated that biochar and,to a lesser degree,earthworms can independently improve soil fertility and crop productivity,although information about their co-application effects on soil characteristics is limited.In this review,(1)earthworm biomarkers and underlying influencing factors,as well as the changes in the amended soil quality in response to co-application of earthworms and biochar are presented,(2)the functional interactions between earthworms and biochar in soil are summarized;(3)the principles governing the synergetic effects of biochar and earthworms on soil quality enhancement are probed;and(4)alternative strategies to optimize the efficacy of earthworm and biochar amendments are provided.It is noteworthy that while low doses of biochar can have a positive effect on various earthworm biomarkers,including growth and reproduction,restoration of the intestinal environment,and the mitigation of cellular organelle toxicity and genetic damage,high biochar dosages can yield adverse effects.Conversely,earthworms play a crucial role in distributing biochar particles deeper into the soil matrix,bolstering carbon sequestration potential,and enhancing the persistence and efficiency of biochar utilization.Moreover,earthworms stimulate the production of soil extracellular enzymes by microorganisms,which are pivotal to the processing,stabilization,and decomposition of soil organic matter,as well as nutrient cycling in terrestrial ecosystems.Additionally,they enhance the binding affinities of these enzymes to biochar.Significantly,changes in earthworm biomarkers in response to biochar integration are predominately governed by biochar properties and dosage,contact time,and soil type.
基金supported by the National Basic Research Program (973) of China (No. 2011CB100503)the National Natural Science Foundation of China (No. 40971141)the Science and Technology Development Project of Jilin Province (No. 201105012)
文摘Biogas slurry is not suitable for liquid fertilizer due to its high amounts of volatile materials being of complicated composition and peculiar smell. In order to remove volatiles from biogas slurry efficiently, the dynamic headspace and gas chromatography-mass spectrometry were used to clear the composition of volatiles. Nitrogen stripping and superfluous ozone were also used to remove volatiles from biogas slurry. The results showed that there were 21 kinds of volatile compounds in the biogas slurry, including sulfur compounds, organic amines, benzene, halogen generation of hydrocarbons and alkanes, some of which had strong peculiar smell. The volatile compounds in biogas slurry can be removed with the rate of 53.0% by nitrogen stripping and with rate of 81.7% by the oxidization and stripping of the superfluous ozone. On this basis, the removal rate of the volatile compounds reached 99.2% by chloroform and n-hexane extraction, and almost all of odor was eliminated. The contents of some dissolved organic compounds decreased obviously and however main plant nutrients had no significant change in the biogas slurry after being treated.
基金We gratefully ack no wledge the support of the National Nature Science Foundation of China (91334201,21506004,21606008)the State Key Laboratory of Chemical Engineering (SKL-ChE-16A01, SKL-ChE-17A02).
文摘Microfluidic systems provide a powerful platform for preparing,functionalizing,and manipulating nano-/micro-materials.In this review,we summarize the characteristics of state-of-the-art microfluidic techniques and their application to processing novel nano-/micro-materials with tunable size,shape,morphology,composition,and properties.A variety of synthesis strategies based on novel microfiuidic devices are presented and compared,including their integration with real-time monitoring,external fields,and automatic feedback control.Novel functional nano-/micro-materials with complex structures have been controllably prepared and post-processed to obtain high-quality products.Strategies for controlling and tuning physical and chemical properties are also examined in terms of the design and function of microfluidic platforms.We provide an outlook on future developments in the processing of nano-/micro-materials by microfluidic technologies.
基金support by the National Natural Science Foundation of China(21537002,41422105,41671478)the Natural Science Foundation of Jiangsu Province,China(Project No.BK20130050).
文摘Biochar is the carbon-rich product obtained from the thermochemical conversion of biomass under oxygen-limited conditions.Biochar has attained extensive attention due to its agronomical and environmental benefits in agro-ecosystems.This work adopts the scientometric analysis method to assess the development trends of biochar research based on the literature data retrieved from the Web of Science over the period of 1998-2018.By analysing the basic characteristics of 6934 publications,we found that the number of publications grew rapidly since 2010.Based on a keyword analysis,it is concluded that scholars have had a fundamental recognition of biochar and preliminarily found that biochar application had agronomic and environmental benefits during the period of 1998-2010.The clustering results of keywords in documents published during 2011-2015 showed that the main research hotspots were“biochar production”,“biochar and global climate change”,“soil quality and plant growth”,“organic pollutants removal”,and“heavy metals immobilization”.While in 2016-2018,beside these five main research hotspots,“biochar and composting”topic had also received greater attention,indicating that biochar utilization in organic solid waste composting is the current research hotspot.Moreover,updated reactors(e.g.,microwave reactor,fixed-bed reactor,screw-feeding reactor,bubbling fluidized bed reactor,etc.)or technologies(e.g.,solar pyrolysis,Thermo-Catalytic Reforming process,liquefaction technology,etc.)applied for efficient energy production and modified biochar for environmental remediation have been extensively studied recently.The findings may help the new researchers to seize the research frontier in the biochar field.
基金supported by the National Basic Research and Development Program (973) of China (No. 2007CB936604)
文摘Transformation of polychlorinated biphenyls (PCBs) by zero-valent iron represents one of the latest innovative technologies for environmental remediation. The dechlorination of 4-chlorobiphenyl (4-C1BP) by nanoscale zero-valent iron (NZVI) in the presence of humic acid or metal ions was investigated. The results showed that the dechlorination of 4-C1BP by NZVI increased with decreased solution pH. When the initial pH value was 4.0, 5.5, 6.8, and 9.0, the de.chlorination efficiencies of 4-CIBP after 48 hr were 53.8%, 47.8%, 35.7%, and 35.6%, respectively. The presence of humic acid inhibited the reduction of 4-CIBP in the first 4 hi', and then significantly accelerated the dechlorination by reaching 86.3% in 48 hr. Divalent metal ions, Co2+, Cu2+, and Ni2+, were reduced and formed bimetals with NZVI, thereby enhanced the dechlorination of 4-CIBP. The dechlorination percentages of 4-CIBP in the presence of 0.1 mmol/L Co2~, Cuz~ and Niz~ were 66.1%, 66.0% and 64.6% in 48 hr, and then increased to 67.9%, 71.3% and 73.5%, after 96 hr respectively. The dechlorination kinetics of 4-C1BP by the NZVI in all cases followed pseudo-first order model. The results provide a basis for better understanding of the dechlorination mechanisms of PCBs in real environment.
基金This work was financially supported by the National Basic Research Foundation of China (grant number 2013CB733600)and the National Natural Science Foundation (grant numbers 21276140,20976096,and 21036002).
文摘In this paper,we present a new method for preparing γ-alumina nanoparticles with a bimodal pore size distribution by using an efficiently mixing membrane dispersion microreactor.NH4HCO3and AI2(SO4)3.18H2Owere reacted under vigorous mixing to give an ammonium aluminum carbonate hydroxide (AACH)precursor.γ-Alumina was obtained by calcination of AACH at 550℃ for 6h.The effects of NH4HCO3concentration,pH during aging,and reaction temperature were investigated.The mechanism of bimodal pore formation was clarified.The results showed that large pores (10-100nm) were mainly formed in the reactor and during aging,and small pores (0-10nm)were mainly formed during calcination.When the concentration of NH4HCO3was 1.5mol/L,the aging pH was 9.2,and the reaction temperature was 80℃,γ-alumina with a specific surface area of 504.7m^2/g and pore volume of 1.76mL/g was obtained.The average size of the large pores was about 30nm,and the average size of the small pores was about 4nm.
基金support by the National Natural Science Foundation of China(21537002)the Special research assistant project,Chinese academy of sciences(Project no.E022ST01).
文摘Biochar,derived from thermal pyrolysis of biomass,has been regarded as a low-cost,sustainable and beneficial material and widely applied in agriculture,environment and energy during the last two decades.To elucidate the research status timely and future trends in biochar field,CiteSpace is used to systematically analyze the related literature retrieved from the Web of Science core collection in 2019.Based on the keywords clustering analysis,it was found that“biochar production”,“organic pollutants removal”,“heavy metals immobilization”,“bioremediation”were the main hotspots in research covering biochar.“Bioremediation”is an emerging topic and deserves extensive attention due to its highly effective and environmentally friendly treatment of pollutants.Improving the phytoremediation effect,immobilizing functional microorganisms on biochar,and using microorganisms as raw materials to produce biochar were the common methods of biochar-assisted bioremediation.While studies focused on“soil quality and plant growth”and“biochar and global climate change”decreased,investigations concentrated in the toxicity of biochar to soil biota and ruminants are sustainably growing.Research on direct and catalytic thermal pyrolysis of green waste(mainly microalgae)for biofuels(bio-oil,biodiesel,syngas,etc.)and biochar production is increasing.Converting municipal wastes(e.g.,sewage sludge,fallen leaves)into biochar through pyrolysis was a suitable treatment for municipal waste and became a popular topic in recent time.Moreover,the biochar produced from these municipal wastes exhibited excellent performance in the removal of pollutants from wastewater and soil.This review may help to identify future directions in biochar research and applications.