A new synthesis method of difenoconazole is studied.Difenoconazole is prepared from m-dichlorobenzene by Friedel Crafts reaction,cyclization,bromination,nucleophilic substitution and etherification.The new process imp...A new synthesis method of difenoconazole is studied.Difenoconazole is prepared from m-dichlorobenzene by Friedel Crafts reaction,cyclization,bromination,nucleophilic substitution and etherification.The new process improves the selectivity of the reaction and simplified the pu-rification process.The total yield of this process is 84%,which provides a green and economical synthetic route for industrialization.展开更多
The phenolic emulsifiers used in emulsified asphalt of micro-surfacing, which was the most important tools in the road maintenance, were investigated by control technology. Many factors influencing this reaction were ...The phenolic emulsifiers used in emulsified asphalt of micro-surfacing, which was the most important tools in the road maintenance, were investigated by control technology. Many factors influencing this reaction were studied and three kinds of phenolic emulsifiers were prepared without catalyst in ethanol. The performance was researched that 2-({2-[2-(2-Amino-ethylamino)-ethylamino]-ethyl-amino}-methyl)-4- nonyl-phenol (abbreviated as TETA) could be used in micro-surface. With addition of 0.5 % demulsifier, the mixing time was extended to 120 seconds obviously, and the cohesion torque (60 min) was 2.8 N*m, which satisfied the opening traffic time shorter than 1 h. The wet track abrasion (6 d) was lower than 807 g/m2, with interracial modifier added, but the load wheel was increased with interfacial modifier increasing. When the TETA: demulsifier: interracial modifier =3:1:3, excellent performance was obtained and the experimental results met the International Slurry Surfacing Association (ISSA) standard. The synthesis process of this emulsifier is simple and the performance used in micro-surface was excellent, so this kind of emulsifier could have a better application future.展开更多
Daidzein has been widely used in pharmaceuticals,nutraceuticals,cosmetics,feed additives,etc.Its preparation process and related reaction mechanism need to be further investigated.A cost-effective process for synthesi...Daidzein has been widely used in pharmaceuticals,nutraceuticals,cosmetics,feed additives,etc.Its preparation process and related reaction mechanism need to be further investigated.A cost-effective process for synthesizing daidzein was developed in this work.In this article,a two-step synthesis of daidzein(Friedel–Crafts acylation and[5+1]cyclization)was developed via the employment of trifluoromethanesulfonic acid(TfOH)as an effective promoting reagent.The effect of reaction conditions such as solvent,the amount of TfOH,reaction temperature,and reactant ratio on the conversion rate and the yield of the reaction,respectively,was systematically investigated,and daidzein was obtained in 74.0%isolated yield under optimal conditions.Due to the facilitating effect of TfOH,the Friedel–Crafts acylation was completed within 10 min at 90℃ and the[5+1]cyclization was completed within 180 min at 25℃.In addition,a possible reaction mechanism for this process was proposed.The results of the study may provide useful guidance for industrial production of daidzein on a large scale.展开更多
The coal-to-ethanol process,as the clean coal utilization,faces challenges from the energy-intensive distillation that separates multi-component effluents for pure ethanol.Referring to at least eight columns,the synth...The coal-to-ethanol process,as the clean coal utilization,faces challenges from the energy-intensive distillation that separates multi-component effluents for pure ethanol.Referring to at least eight columns,the synthesis of the ethanol distillation system is impracticable for exhaustive comparison and difficult for conventional superstructure-based optimization as rigorous models are used.This work adopts a superstructure-based framework,which combines the strategy that adaptively selects branches of the state-equipment network and the parallel stochastic algorithm for process synthesis.High-performance computing significantly reduces time consumption,and the adaptive strategy substantially lowers the complexity of the superstructure model.Moreover,parallel computing,elite search,population redistribution,and retention strategies for irrelevant parameters are used to improve the optimization efficiency further.The optimization terminates after 3000 generations,providing a flowsheet solution that applies two non-sharp splitting options in its distillation sequence.As a result,the 59-dimension superstructure-based optimization was solved efficiently via a differential evolution algorithm,and a high-quality solution with a 28.34%lower total annual cost than the benchmark was obtained.Meanwhile,the solution of the superstructure-based optimization is comparable to that obtained by optimizing a single specific configuration one by one.It indicates that the superstructure-based optimization that combines the adaptive strategy can be a promising approach to handling the process synthesis of large-scale and complex chemical processes.展开更多
This study focuses on drawing a hydrothermal synthesis process map for Co3O4 nanoparticles with various morphologies and investigating the effects of Co3O4 nanocatalyst morphology on CO oxidation.A series of cobalt-hy...This study focuses on drawing a hydrothermal synthesis process map for Co3O4 nanoparticles with various morphologies and investigating the effects of Co3O4 nanocatalyst morphology on CO oxidation.A series of cobalt-hydroxide-carbonate nanoparticles with various morphologies(i.e.,nanorods,nanosheets,and nanocubes) were successfully synthesized,and Co3O4 nanoparticles were obtained by thermal decomposition of the cobalt-hydroxide-carbonate precursors.The results suggest that the cobalt source is a key factor for controlling the morphology of cobalt-hydroxide-carbonate at relatively low hydrothermal temperatures(≤ 140℃).Nanorods can be synthesized in CoCl2 solution,while Co(NO3)2 solution promotes the formation of nanosheets.Further increasing the synthesis temperature(higher than 140 ℃) results in the formation of nanocubes in either Co(NO3)2 or CoCl2 solution.The reaction time only affects the size of the obtained nanoparticles.The presence of CTAB could improve the uniformity and dispersion of particles.Co3O4 nanosheets showed much higher catalytic activity for CO oxidation than nanorods and nanocubes because it has more abundant Co^(3+) on the surface,much higher reducibility,and better oxygen desorption capacity.展开更多
Steady-state non-dominated sorting genetic algorithm (SNSGA), a new form of multi-objective genetic algorithm, is implemented by combining the steady-state idea in steady-state genetic algorithms (SSGA) and the fitnes...Steady-state non-dominated sorting genetic algorithm (SNSGA), a new form of multi-objective genetic algorithm, is implemented by combining the steady-state idea in steady-state genetic algorithms (SSGA) and the fitness assignment strategy of non-dominated sorting genetic algorithm (NSGA). The fitness assignment strategy is improved and a new self-adjustment scheme of is proposed. This algorithm is proved to be very efficient both computationally and in terms of the quality of the Pareto fronts produced with five test problems including GA difficult problem and GA deceptive one. Finally, SNSGA is introduced to solve multi-objective mixed integer linear programming (MILP) and mixed integer non-linear programming (MINLP) problems in process synthesis.展开更多
A novel process for catalytic oxidation of methane to synthesis gas (syngas), which consists of two consecutive fixed-bed reactors with air introduced into the reactors, integrated Fischer-Tropsch synthesis, was inves...A novel process for catalytic oxidation of methane to synthesis gas (syngas), which consists of two consecutive fixed-bed reactors with air introduced into the reactors, integrated Fischer-Tropsch synthesis, was investigated. At the same time, a catalytic combustion technology has been investigated for utilizing the F-T offgas to generate heat or power energy. The results show that the two-stage fixed reactor process keep away from explosion of CH4/O2. The integrated process is fitted to produce diesel oil and lubricating oil in remote gas field.展开更多
A predictive parallel search algorithm,the fuzzy match inference strategy,is implemented ina prototype expert system.Selection of separation technologies and sequencing of separators are beingapproached in an integrat...A predictive parallel search algorithm,the fuzzy match inference strategy,is implemented ina prototype expert system.Selection of separation technologies and sequencing of separators are beingapproached in an integrated manner.The fuzzy match mechanism results in a relatively smaller subsetof favored schemes,constituting a hyperstructure for further quantitative evaluation and combinationoptimization.An industrial application example of aromatics extraction separation is presented.展开更多
Potassium bismuth titanate nanosized powders were prepared by the hydrothermal method using Ti(C_4H_9O)_4 and Bi(NO_3)_3·5H_2O as raw materials in alkaline solution.The phase composition,particle size and morphol...Potassium bismuth titanate nanosized powders were prepared by the hydrothermal method using Ti(C_4H_9O)_4 and Bi(NO_3)_3·5H_2O as raw materials in alkaline solution.The phase composition,particle size and morphology of the powders were studied by XRD and TEM analysis.The results showed that the powders were well crystallized and dispersed.The crystal phase of the powders was K_(0.5)Bi_(0.5)TiO_3 with the grain size of about 50 nm~100 nm.Hydrothermal temperature and alkaline concentrations had great effects on the phase composition and morphology of the resultant powders.Pure K_(0.5)Bi_(0.5)TiO_3 powders could be synthesized at 170℃~180℃with KOH concentration of 8 mol/L~12 mol/L.展开更多
An effective and reproducible preparation of silica sol nanospheres via a modified sol-gel process has been described. Monodisperse and stable silica sol nanospheres with uniformsize were successfully obtained through...An effective and reproducible preparation of silica sol nanospheres via a modified sol-gel process has been described. Monodisperse and stable silica sol nanospheres with uniformsize were successfully obtained through the optimized synthesis in which the mixture of tetraethyl orthosilicate (TEOS) and ethanol was followed by the addition of water and ammonium hydroxide (NH3) separately, and the size of silica sol spheres was strictly controlled in the range of 25-119 nm with a narrow size distribution by fine adjustment of several reaction parameters. Results showed that in the presence of low concentration of TEOS, spheres size rose first and reached maximum when H2O concentration was up to 66 g/L. However, the diameter of silica sol spheres decreased above 66 g/L of H2O concentration. Furthermore, it was also found that the size and size distribution of silica sol nanospheres were affected by NH3 concentration. As NH3 concentration increased from 15 to 35 g/L, the diameter declined from 83 to 64 nm. Nevertheless, higher NH3 concentration would result in relatively broad size distribution, and gelation occurred when NH3 concentration reached 44 g/L. In addition, the effect of the different feed rates ofNH3 on the size growth of silica sol nanospheres was also discussed.展开更多
The reaction process of combustion synthesis for TiB2 -Cu was investigated in detail using combustion-wave arresting experiment, X-ray diffraction ( XRD ) analysis, SEM analysis and differential thermal analysis ( ...The reaction process of combustion synthesis for TiB2 -Cu was investigated in detail using combustion-wave arresting experiment, X-ray diffraction ( XRD ) analysis, SEM analysis and differential thermal analysis ( DTA ). The XRD analysis results for the different parts of the quenched specimen show that TiCux intermetallic phase firstly forms with the propagation of combustion wave, and then Ti1.87 B50 and Ti3B4 metastable phases come forth due to the diffusion of B atoms and finally the stable TiB2 phase forms because of the continuous diffusion of B atoms. The formation of TiB2 phase is uot completed by one step, but undergoes several transient processes. The process of reaction synthesis for Ti-B-Cu ternary system can be divided into three main stages: melting of Cu and Ti , and the formation of Cu- Ti melt and few TiCux , TiBx intermetallic phases ; large numbers of TiCux intermetallic phases formation and some fine TiB2 particles precipitation ; and the TiB2 particles coarsening and the stable TiB2 and Cu two phases formation in the final product.展开更多
In the realm of the synthesis of heat-integrated distillation configurations,the conventional approach for exploring more heat integration possibilities typically entails the splitting of a single column into a twocol...In the realm of the synthesis of heat-integrated distillation configurations,the conventional approach for exploring more heat integration possibilities typically entails the splitting of a single column into a twocolumn configuration.However,this approach frequently necessitates tedious enumeration procedures,resulting in a considerable computational burden.To surmount this formidable challenge,the present study introduces an innovative remedy:The proposition of a superstructure that encompasses both single-column and multiple two-column configurations.Additionally,a simultaneous optimization algorithm is applied to optimize both the process parameters and heat integration structures of the twocolumn configurations.The effectiveness of this approach is demonstrated through a case study focusing on industrial organosilicon separation.The results underscore that the superstructure methodology not only substantially mitigates computational time compared to exhaustive enumeration but also furnishes solutions that exhibit comparable performance.展开更多
Recently,the increasing interest in wearable technology for personal healthcare and smart virtual/augmented reality applications has led to the development of facile fabrication methods.Lasers have long been used to d...Recently,the increasing interest in wearable technology for personal healthcare and smart virtual/augmented reality applications has led to the development of facile fabrication methods.Lasers have long been used to develop original solutions to such challenging technological problems due to their remote,sterile,rapid,and site-selective processing of materials.In this review,recent developments in relevant laser processes are summarized under two separate categories.First,transformative approaches,such as for laser-induced graphene,are introduced.In addition to design optimization and the alteration of a native substrate,the latest advances under a transformative approach now enable more complex material compositions and multilayer device configurations through the simultaneous transformation of heterogeneous precursors,or the sequential addition of functional layers coupled with other electronic elements.In addition,the more conventional laser techniques,such as ablation,sintering,and synthesis,can still be used to enhance the functionality of an entire system through the expansion of applicable materials and the adoption of new mechanisms.Later,various wearable device components developed through the corresponding laser processes are discussed,with an emphasis on chemical/physical sensors and energy devices.In addition,special attention is given to applications that use multiple laser sources or processes,which lay the foundation for the all-laser fabrication of wearable devices.展开更多
Two classes of inorganic materials such as metallic nanowires and metal oxides nanorods were synthesized using the polyol process and scaled-up to produce macroscopic quantities. Scale-up strategy was successfully bui...Two classes of inorganic materials such as metallic nanowires and metal oxides nanorods were synthesized using the polyol process and scaled-up to produce macroscopic quantities. Scale-up strategy was successfully built by performing the synthesis in a 15 cm diameter, 4.5 litersvolume cylindrical tank using a straight paddle impeller and a Rushton turbine. The actual yield of the synthesis is ~45 grams per batch for zinc oxide nanorods and ~20 grams per batch for cobalt nickel nanowires. Under the same rotation speed, the aspect ratio of the produced nanowires and nanorods using the Rushton turbine impeller with radial flow patterns has shown a lower aspect ratio, nanoparticle size and polydispersity. This is attributed to the increase of the local dissipated energy as spatially calculated by computational fluid dynamics (CFD) that is proposed to design, optimize and scale-up the polyol process.展开更多
In conventional heterogeneous catalytic process, the activation of C-H bond remains a grand challenge. It is even more difficult to activate the inert C-H bond with other functional groups (e.g. OH) in the same mole...In conventional heterogeneous catalytic process, the activation of C-H bond remains a grand challenge. It is even more difficult to activate the inert C-H bond with other functional groups (e.g. OH) in the same molecule, remaining intact [1]. Although the transformation of C1 species (e.g. CO, CO2, CH4 and CH3OH) into C2 molecules (e.g. C2H4, C2HsOH and HOCH2CH2OH) via C-C coupling has been a hot research topic but the yield of aimed product is still needed to be improved. Ethylene glycol (EG) is a versatile chemical with many important applications, in particular for the manufacture of polyesters, predominantly poly(ethylene terephthalate) [2]. Recently, Wang, Deng and co-workers at Xiamen University cleverly designed a new process for the conversion of methanol to ethylene glycol, in which the EG selectivity can reach 90% (Eq. (1)) [3].展开更多
The mechanism of scaling on the oxidation reactor wall in TiO2 synthesis process was investigated. The formation of wall scale is mostly due to being deposited and sintered of TiO2 particle formed in the gas phase rea...The mechanism of scaling on the oxidation reactor wall in TiO2 synthesis process was investigated. The formation of wall scale is mostly due to being deposited and sintered of TiO2 particle formed in the gas phase reaction of TiCl4 with O2. The gas-phase oxidation of TiCl4 was in a high temperature tubular flow reactor with quartz and ceramic rods put in center respectively. Scale layers are formed on reactor wall and two rods. Morphology and phase composition of them were characterized by transmission electron microscope(TEM), scan electron micrographs(SEM) and X-ray diffraction(XRD). The state of reactor wall has a little effect on scaling formation. With uneven temperature distribution along axial of reactor, the higher the reaction temperature is,the thicker the scale layer and the more compact the scale structure is.展开更多
Ammonia is essential for food and energy.Industrial ammonia synthesis via Haber–Bosch process is energy-intensive and releases large amount of CO2.Increasing research efforts are devoted to "green"ammonia s...Ammonia is essential for food and energy.Industrial ammonia synthesis via Haber–Bosch process is energy-intensive and releases large amount of CO2.Increasing research efforts are devoted to "green"ammonia synthesis.The present article reviews the recent progress in the fields of thermocatalytic, electrocatalytic, photocatalytic and chemical looping processes for dinitrogen reduction towards ammonia formation and discusses the challenges borne for mild-condition synthesis.展开更多
Landscape ecology provides new theoretical frameworks and methodologies for understanding complex ecological phenomena at multiple scales.Studies of landscape ecology focus on understanding the dynamics of eco-logical...Landscape ecology provides new theoretical frameworks and methodologies for understanding complex ecological phenomena at multiple scales.Studies of landscape ecology focus on understanding the dynamics of eco-logical patterns and processes,and highlight the integration of multiple disciplines.In this paper,we discussed the problems and challenges that landscape ecology is currently facing,emphasizing the limitations of current methods used to describe dynamic landscape patterns and processes.We suggested that the focus should be on the integration of ground-based observation,mobile monitoring,transect survey,and remote-sensing monitoring,as well as improved coupling of experimental and model simulations.In addition,we outlined the research frontiers in landscape ecology,including scaling,integrated pattern and process modeling,and regional synthesis.Lastly,a brief review of pat-tern-process-scale coupling studies in China was provided.We concluded by pointing out that pattern-process-scale interactions,correlations between natural,economic,and social processes,and the coupling of human and natural systems will be major research areas in landscape ecology in the future.展开更多
In this work, a fast(0.5 h), green microwave-assisted synthesis of single crystalline Sb_2Se_3 nanowires was developed. For the first time we demonstrated a facile solvent-mediated process, whereby intriguing nanostru...In this work, a fast(0.5 h), green microwave-assisted synthesis of single crystalline Sb_2Se_3 nanowires was developed. For the first time we demonstrated a facile solvent-mediated process, whereby intriguing nanostructures including antimony selenide(Sb_2Se_3) nanowires and selenium(Se) microrods can be achieved by merely varying the volume ratio of ethylene glycol(EG) and H_2O free from expensive chemical and additional surfactant. The achieved uniform Sb_2Se_3 nanowire is single crystalline along [001]growth direction with a diameter of 100 nm and a length up to tens of micrometers. When evaluated as an anode of lithium-ion battery, Sb_2Se_3 nanowire can deliver a high reversible capacity of 650.2 m Ah g^(-1) at 100 mA g^(-1) and a capacity retention of 63.8% after long-term 1000 cycles at 1000 mA g^(-1), as well as superior rate capability(389.5 m Ah g^(-1) at 2000 mA g^(-1)). This easy solvent-mediated microwave synthesis approach exhibits its great universe and importance towards the fabrication of high-performance metal chalcogenide electrode materials for future low-cost, large-scale energy storage systems.展开更多
β-Sialon based composites were successfully prepared from fly ash and carbon black under nitrogen atmosphere by carbothermal reduction-nitridation process. Effects of heating temperature and raw materials composition...β-Sialon based composites were successfully prepared from fly ash and carbon black under nitrogen atmosphere by carbothermal reduction-nitridation process. Effects of heating temperature and raw materials composition on synthesis process were investigated, and the formation process of the composites was also discussed. The phase composition and microstructure of the composites were characterized by X-ray diffraction and scanning electronic microscopy. The results show that increasing heating temperature or mass ratio of carbon black to fly ash can promote the formation of β-Sialon. The β-Sialon based composites can be synthesized at 1723 K for 6 h while heating the sample with mass ratio of carbon black to fly ash of 0.56. The as-received β-Sialon in the composites exists as granular with an average particle size of 2-3 μm. The preparation process of β-Sialon based composites includes the formation of O′-Sialon, X-Sialon and β-Sialon as well as the conversion processes of O′-Sialon and X-Sialon to β-Sialon.展开更多
文摘A new synthesis method of difenoconazole is studied.Difenoconazole is prepared from m-dichlorobenzene by Friedel Crafts reaction,cyclization,bromination,nucleophilic substitution and etherification.The new process improves the selectivity of the reaction and simplified the pu-rification process.The total yield of this process is 84%,which provides a green and economical synthetic route for industrialization.
基金Funded by the National Key Basic Research and Development Plan(No.2012CB724601)the Jiangsu Provincial Natural Science Foundation(No.BK 2008503)
文摘The phenolic emulsifiers used in emulsified asphalt of micro-surfacing, which was the most important tools in the road maintenance, were investigated by control technology. Many factors influencing this reaction were studied and three kinds of phenolic emulsifiers were prepared without catalyst in ethanol. The performance was researched that 2-({2-[2-(2-Amino-ethylamino)-ethylamino]-ethyl-amino}-methyl)-4- nonyl-phenol (abbreviated as TETA) could be used in micro-surface. With addition of 0.5 % demulsifier, the mixing time was extended to 120 seconds obviously, and the cohesion torque (60 min) was 2.8 N*m, which satisfied the opening traffic time shorter than 1 h. The wet track abrasion (6 d) was lower than 807 g/m2, with interracial modifier added, but the load wheel was increased with interfacial modifier increasing. When the TETA: demulsifier: interracial modifier =3:1:3, excellent performance was obtained and the experimental results met the International Slurry Surfacing Association (ISSA) standard. The synthesis process of this emulsifier is simple and the performance used in micro-surface was excellent, so this kind of emulsifier could have a better application future.
基金the Science and Technology Planning Project of Guangdong Province(2016B090934002)Guangdong Provincial Natural Science Foundation(2023A1515011640)for financial support.
文摘Daidzein has been widely used in pharmaceuticals,nutraceuticals,cosmetics,feed additives,etc.Its preparation process and related reaction mechanism need to be further investigated.A cost-effective process for synthesizing daidzein was developed in this work.In this article,a two-step synthesis of daidzein(Friedel–Crafts acylation and[5+1]cyclization)was developed via the employment of trifluoromethanesulfonic acid(TfOH)as an effective promoting reagent.The effect of reaction conditions such as solvent,the amount of TfOH,reaction temperature,and reactant ratio on the conversion rate and the yield of the reaction,respectively,was systematically investigated,and daidzein was obtained in 74.0%isolated yield under optimal conditions.Due to the facilitating effect of TfOH,the Friedel–Crafts acylation was completed within 10 min at 90℃ and the[5+1]cyclization was completed within 180 min at 25℃.In addition,a possible reaction mechanism for this process was proposed.The results of the study may provide useful guidance for industrial production of daidzein on a large scale.
文摘The coal-to-ethanol process,as the clean coal utilization,faces challenges from the energy-intensive distillation that separates multi-component effluents for pure ethanol.Referring to at least eight columns,the synthesis of the ethanol distillation system is impracticable for exhaustive comparison and difficult for conventional superstructure-based optimization as rigorous models are used.This work adopts a superstructure-based framework,which combines the strategy that adaptively selects branches of the state-equipment network and the parallel stochastic algorithm for process synthesis.High-performance computing significantly reduces time consumption,and the adaptive strategy substantially lowers the complexity of the superstructure model.Moreover,parallel computing,elite search,population redistribution,and retention strategies for irrelevant parameters are used to improve the optimization efficiency further.The optimization terminates after 3000 generations,providing a flowsheet solution that applies two non-sharp splitting options in its distillation sequence.As a result,the 59-dimension superstructure-based optimization was solved efficiently via a differential evolution algorithm,and a high-quality solution with a 28.34%lower total annual cost than the benchmark was obtained.Meanwhile,the solution of the superstructure-based optimization is comparable to that obtained by optimizing a single specific configuration one by one.It indicates that the superstructure-based optimization that combines the adaptive strategy can be a promising approach to handling the process synthesis of large-scale and complex chemical processes.
基金supported by the National Natural Science Foundation of China (51374004,51204083)the Candidate Talents Training Fund of Yun-nan Province (2012HB009,2014HB006)+2 种基金the Applied Basic Research Program of Yunnan Province (2014FB123)a School-Enterprise Cooperation Project from Jinchuan Corporation (Jinchuan 201115)the Talents Training Program of Kunming University of Science and Technology (KKZ3201352038)~~
文摘This study focuses on drawing a hydrothermal synthesis process map for Co3O4 nanoparticles with various morphologies and investigating the effects of Co3O4 nanocatalyst morphology on CO oxidation.A series of cobalt-hydroxide-carbonate nanoparticles with various morphologies(i.e.,nanorods,nanosheets,and nanocubes) were successfully synthesized,and Co3O4 nanoparticles were obtained by thermal decomposition of the cobalt-hydroxide-carbonate precursors.The results suggest that the cobalt source is a key factor for controlling the morphology of cobalt-hydroxide-carbonate at relatively low hydrothermal temperatures(≤ 140℃).Nanorods can be synthesized in CoCl2 solution,while Co(NO3)2 solution promotes the formation of nanosheets.Further increasing the synthesis temperature(higher than 140 ℃) results in the formation of nanocubes in either Co(NO3)2 or CoCl2 solution.The reaction time only affects the size of the obtained nanoparticles.The presence of CTAB could improve the uniformity and dispersion of particles.Co3O4 nanosheets showed much higher catalytic activity for CO oxidation than nanorods and nanocubes because it has more abundant Co^(3+) on the surface,much higher reducibility,and better oxygen desorption capacity.
文摘Steady-state non-dominated sorting genetic algorithm (SNSGA), a new form of multi-objective genetic algorithm, is implemented by combining the steady-state idea in steady-state genetic algorithms (SSGA) and the fitness assignment strategy of non-dominated sorting genetic algorithm (NSGA). The fitness assignment strategy is improved and a new self-adjustment scheme of is proposed. This algorithm is proved to be very efficient both computationally and in terms of the quality of the Pareto fronts produced with five test problems including GA difficult problem and GA deceptive one. Finally, SNSGA is introduced to solve multi-objective mixed integer linear programming (MILP) and mixed integer non-linear programming (MINLP) problems in process synthesis.
基金Supported by the Major State Basic Research Projects of the Ministry of Science and Technology of China (G1999022402).
文摘A novel process for catalytic oxidation of methane to synthesis gas (syngas), which consists of two consecutive fixed-bed reactors with air introduced into the reactors, integrated Fischer-Tropsch synthesis, was investigated. At the same time, a catalytic combustion technology has been investigated for utilizing the F-T offgas to generate heat or power energy. The results show that the two-stage fixed reactor process keep away from explosion of CH4/O2. The integrated process is fitted to produce diesel oil and lubricating oil in remote gas field.
基金Supported in parts by the National Natural Science Foundation of China, the state Commission of Education of China
文摘A predictive parallel search algorithm,the fuzzy match inference strategy,is implemented ina prototype expert system.Selection of separation technologies and sequencing of separators are beingapproached in an integrated manner.The fuzzy match mechanism results in a relatively smaller subsetof favored schemes,constituting a hyperstructure for further quantitative evaluation and combinationoptimization.An industrial application example of aromatics extraction separation is presented.
文摘Potassium bismuth titanate nanosized powders were prepared by the hydrothermal method using Ti(C_4H_9O)_4 and Bi(NO_3)_3·5H_2O as raw materials in alkaline solution.The phase composition,particle size and morphology of the powders were studied by XRD and TEM analysis.The results showed that the powders were well crystallized and dispersed.The crystal phase of the powders was K_(0.5)Bi_(0.5)TiO_3 with the grain size of about 50 nm~100 nm.Hydrothermal temperature and alkaline concentrations had great effects on the phase composition and morphology of the resultant powders.Pure K_(0.5)Bi_(0.5)TiO_3 powders could be synthesized at 170℃~180℃with KOH concentration of 8 mol/L~12 mol/L.
基金Funded by the Guangdong Well-Silicasol Company Limited,China
文摘An effective and reproducible preparation of silica sol nanospheres via a modified sol-gel process has been described. Monodisperse and stable silica sol nanospheres with uniformsize were successfully obtained through the optimized synthesis in which the mixture of tetraethyl orthosilicate (TEOS) and ethanol was followed by the addition of water and ammonium hydroxide (NH3) separately, and the size of silica sol spheres was strictly controlled in the range of 25-119 nm with a narrow size distribution by fine adjustment of several reaction parameters. Results showed that in the presence of low concentration of TEOS, spheres size rose first and reached maximum when H2O concentration was up to 66 g/L. However, the diameter of silica sol spheres decreased above 66 g/L of H2O concentration. Furthermore, it was also found that the size and size distribution of silica sol nanospheres were affected by NH3 concentration. As NH3 concentration increased from 15 to 35 g/L, the diameter declined from 83 to 64 nm. Nevertheless, higher NH3 concentration would result in relatively broad size distribution, and gelation occurred when NH3 concentration reached 44 g/L. In addition, the effect of the different feed rates ofNH3 on the size growth of silica sol nanospheres was also discussed.
基金Funded bythe Aerospace Innovation Fundation andthe ResearchFund by the Doctoral Program of High Education ( No.20020213037)
文摘The reaction process of combustion synthesis for TiB2 -Cu was investigated in detail using combustion-wave arresting experiment, X-ray diffraction ( XRD ) analysis, SEM analysis and differential thermal analysis ( DTA ). The XRD analysis results for the different parts of the quenched specimen show that TiCux intermetallic phase firstly forms with the propagation of combustion wave, and then Ti1.87 B50 and Ti3B4 metastable phases come forth due to the diffusion of B atoms and finally the stable TiB2 phase forms because of the continuous diffusion of B atoms. The formation of TiB2 phase is uot completed by one step, but undergoes several transient processes. The process of reaction synthesis for Ti-B-Cu ternary system can be divided into three main stages: melting of Cu and Ti , and the formation of Cu- Ti melt and few TiCux , TiBx intermetallic phases ; large numbers of TiCux intermetallic phases formation and some fine TiB2 particles precipitation ; and the TiB2 particles coarsening and the stable TiB2 and Cu two phases formation in the final product.
文摘In the realm of the synthesis of heat-integrated distillation configurations,the conventional approach for exploring more heat integration possibilities typically entails the splitting of a single column into a twocolumn configuration.However,this approach frequently necessitates tedious enumeration procedures,resulting in a considerable computational burden.To surmount this formidable challenge,the present study introduces an innovative remedy:The proposition of a superstructure that encompasses both single-column and multiple two-column configurations.Additionally,a simultaneous optimization algorithm is applied to optimize both the process parameters and heat integration structures of the twocolumn configurations.The effectiveness of this approach is demonstrated through a case study focusing on industrial organosilicon separation.The results underscore that the superstructure methodology not only substantially mitigates computational time compared to exhaustive enumeration but also furnishes solutions that exhibit comparable performance.
基金supported by the Basic Research Program through the National Research Foundation of Korea(NRF)(Nos.2022R1C1C1006593,2022R1A4A3031263,and RS-2023-00271166)the National Science Foundation(Nos.2054098 and 2213693)+1 种基金the National Natural Science Foundation of China(No.52105593)Zhejiang Provincial Natural Science Foundation of China(No.LDQ24E050001).EH acknowledges a fellowship from the Hyundai Motor Chung Mong-Koo Foundation.
文摘Recently,the increasing interest in wearable technology for personal healthcare and smart virtual/augmented reality applications has led to the development of facile fabrication methods.Lasers have long been used to develop original solutions to such challenging technological problems due to their remote,sterile,rapid,and site-selective processing of materials.In this review,recent developments in relevant laser processes are summarized under two separate categories.First,transformative approaches,such as for laser-induced graphene,are introduced.In addition to design optimization and the alteration of a native substrate,the latest advances under a transformative approach now enable more complex material compositions and multilayer device configurations through the simultaneous transformation of heterogeneous precursors,or the sequential addition of functional layers coupled with other electronic elements.In addition,the more conventional laser techniques,such as ablation,sintering,and synthesis,can still be used to enhance the functionality of an entire system through the expansion of applicable materials and the adoption of new mechanisms.Later,various wearable device components developed through the corresponding laser processes are discussed,with an emphasis on chemical/physical sensors and energy devices.In addition,special attention is given to applications that use multiple laser sources or processes,which lay the foundation for the all-laser fabrication of wearable devices.
文摘Two classes of inorganic materials such as metallic nanowires and metal oxides nanorods were synthesized using the polyol process and scaled-up to produce macroscopic quantities. Scale-up strategy was successfully built by performing the synthesis in a 15 cm diameter, 4.5 litersvolume cylindrical tank using a straight paddle impeller and a Rushton turbine. The actual yield of the synthesis is ~45 grams per batch for zinc oxide nanorods and ~20 grams per batch for cobalt nickel nanowires. Under the same rotation speed, the aspect ratio of the produced nanowires and nanorods using the Rushton turbine impeller with radial flow patterns has shown a lower aspect ratio, nanoparticle size and polydispersity. This is attributed to the increase of the local dissipated energy as spatially calculated by computational fluid dynamics (CFD) that is proposed to design, optimize and scale-up the polyol process.
文摘In conventional heterogeneous catalytic process, the activation of C-H bond remains a grand challenge. It is even more difficult to activate the inert C-H bond with other functional groups (e.g. OH) in the same molecule, remaining intact [1]. Although the transformation of C1 species (e.g. CO, CO2, CH4 and CH3OH) into C2 molecules (e.g. C2H4, C2HsOH and HOCH2CH2OH) via C-C coupling has been a hot research topic but the yield of aimed product is still needed to be improved. Ethylene glycol (EG) is a versatile chemical with many important applications, in particular for the manufacture of polyesters, predominantly poly(ethylene terephthalate) [2]. Recently, Wang, Deng and co-workers at Xiamen University cleverly designed a new process for the conversion of methanol to ethylene glycol, in which the EG selectivity can reach 90% (Eq. (1)) [3].
文摘The mechanism of scaling on the oxidation reactor wall in TiO2 synthesis process was investigated. The formation of wall scale is mostly due to being deposited and sintered of TiO2 particle formed in the gas phase reaction of TiCl4 with O2. The gas-phase oxidation of TiCl4 was in a high temperature tubular flow reactor with quartz and ceramic rods put in center respectively. Scale layers are formed on reactor wall and two rods. Morphology and phase composition of them were characterized by transmission electron microscope(TEM), scan electron micrographs(SEM) and X-ray diffraction(XRD). The state of reactor wall has a little effect on scaling formation. With uneven temperature distribution along axial of reactor, the higher the reaction temperature is,the thicker the scale layer and the more compact the scale structure is.
基金the financial supports from the National Natural Science Foundation of China (Grant nos.21633011, 21603220 and 21872137)Sino-Japanese Research Cooperative Program of Ministry of Science and Technology (2016YFE0118300)Youth Innovation Promotion Association CAS (No.2018213)
文摘Ammonia is essential for food and energy.Industrial ammonia synthesis via Haber–Bosch process is energy-intensive and releases large amount of CO2.Increasing research efforts are devoted to "green"ammonia synthesis.The present article reviews the recent progress in the fields of thermocatalytic, electrocatalytic, photocatalytic and chemical looping processes for dinitrogen reduction towards ammonia formation and discusses the challenges borne for mild-condition synthesis.
基金Under the auspices of National Natural Science Foundation of China (No.40930528)State Forestry Administration of China (No.201004058)
文摘Landscape ecology provides new theoretical frameworks and methodologies for understanding complex ecological phenomena at multiple scales.Studies of landscape ecology focus on understanding the dynamics of eco-logical patterns and processes,and highlight the integration of multiple disciplines.In this paper,we discussed the problems and challenges that landscape ecology is currently facing,emphasizing the limitations of current methods used to describe dynamic landscape patterns and processes.We suggested that the focus should be on the integration of ground-based observation,mobile monitoring,transect survey,and remote-sensing monitoring,as well as improved coupling of experimental and model simulations.In addition,we outlined the research frontiers in landscape ecology,including scaling,integrated pattern and process modeling,and regional synthesis.Lastly,a brief review of pat-tern-process-scale coupling studies in China was provided.We concluded by pointing out that pattern-process-scale interactions,correlations between natural,economic,and social processes,and the coupling of human and natural systems will be major research areas in landscape ecology in the future.
基金supported by the National Key Research and Development Program of China(2016YFA0202603)the National Basic Research Program of China(2013CB934103)+5 种基金the National Natural Science Foundation of China(51521001,51602239)the National Natural Science Fund for Distinguished Young Scholars(51425204)Yellow Crane Talent(Science&Technology)Program of Wuhan Citythe Fundamental Research Funds for the Central Universities(WUT:2016III001,2016III003,2016IVA090)the Programme of Introducing Talents of Discipline to Universities(B17034)support from the Lorraine Region(nowpart of Grand Est Region)Cooperation Research Lorraine/Hubei Program 2015/2017
文摘In this work, a fast(0.5 h), green microwave-assisted synthesis of single crystalline Sb_2Se_3 nanowires was developed. For the first time we demonstrated a facile solvent-mediated process, whereby intriguing nanostructures including antimony selenide(Sb_2Se_3) nanowires and selenium(Se) microrods can be achieved by merely varying the volume ratio of ethylene glycol(EG) and H_2O free from expensive chemical and additional surfactant. The achieved uniform Sb_2Se_3 nanowire is single crystalline along [001]growth direction with a diameter of 100 nm and a length up to tens of micrometers. When evaluated as an anode of lithium-ion battery, Sb_2Se_3 nanowire can deliver a high reversible capacity of 650.2 m Ah g^(-1) at 100 mA g^(-1) and a capacity retention of 63.8% after long-term 1000 cycles at 1000 mA g^(-1), as well as superior rate capability(389.5 m Ah g^(-1) at 2000 mA g^(-1)). This easy solvent-mediated microwave synthesis approach exhibits its great universe and importance towards the fabrication of high-performance metal chalcogenide electrode materials for future low-cost, large-scale energy storage systems.
基金Project (51074038) supported by the National Natural Science Foundation of ChinaProject (N100302002) supported by the Fundamental Research Funds for the Central Universities, China
文摘β-Sialon based composites were successfully prepared from fly ash and carbon black under nitrogen atmosphere by carbothermal reduction-nitridation process. Effects of heating temperature and raw materials composition on synthesis process were investigated, and the formation process of the composites was also discussed. The phase composition and microstructure of the composites were characterized by X-ray diffraction and scanning electronic microscopy. The results show that increasing heating temperature or mass ratio of carbon black to fly ash can promote the formation of β-Sialon. The β-Sialon based composites can be synthesized at 1723 K for 6 h while heating the sample with mass ratio of carbon black to fly ash of 0.56. The as-received β-Sialon in the composites exists as granular with an average particle size of 2-3 μm. The preparation process of β-Sialon based composites includes the formation of O′-Sialon, X-Sialon and β-Sialon as well as the conversion processes of O′-Sialon and X-Sialon to β-Sialon.