A novel A1-Ti-C master alloy containing A14C3 and TiC particle clusters, which exhibits great refining potential for Mg, was prepared. With the addition of 2% A1-Ti-C master alloy, the grains transform to equiaxed cry...A novel A1-Ti-C master alloy containing A14C3 and TiC particle clusters, which exhibits great refining potential for Mg, was prepared. With the addition of 2% A1-Ti-C master alloy, the grains transform to equiaxed crystal with a diameter of (110-a:17) ~tm. The results indicate that A14C3 and TiC particle cluster, rather than a single particle, plays an important role in the refining process. Compared with the simplex smooth nucleating substrate, concave regions on the particle cluster provide easier route for the transformation from liquid Mg atoms to stable nucleus. Nucleus with a small size can also reach the critical nucleation radius when they attach on the concave regions of the substrate. A14C3 and TiC particle clusters thus become more favorable nucleating substrate for a-Mg grains.展开更多
The magnetization curves of MnFe2O4 nanoparticles and self-formed ferrofluids based on these particles have been measured at room temperature. The median size of the particles is 13.67 nm. The specific saturation magn...The magnetization curves of MnFe2O4 nanoparticles and self-formed ferrofluids based on these particles have been measured at room temperature. The median size of the particles is 13.67 nm. The specific saturation magnetization is less than the theoretical value for the ferrofluids. In the high field range from 5 kOe to 10 kOe, the higher the particle volume fraction is, the steeper the slope of the magnetization curves is when it approaches saturation. The behavior of the saturation magnetization and the law of approach to saturation are due to the presence of self-assembled aggregates of ring-like micelle structures which form in the absence of the magnetic field and field-induced aggregates, respectively. The field-induced aggregates have a dissipative structure, so that at high field, the law of approach to saturation magnetization is different from the one described using Langevin paramagnetism theory. The large particles in the ferrofluids result in apparent hysteresis.展开更多
To test the particles solidity and to verify the separating efficiency at normal atmospheric temperature, the experimental research was made on the enhanced cyclone separation of acoustic agglomerated fly ash particl...To test the particles solidity and to verify the separating efficiency at normal atmospheric temperature, the experimental research was made on the enhanced cyclone separation of acoustic agglomerated fly ash particles. The separating efficiency has increased by 3%-4% in a sound field with 150 dB pressure level compared with that obtained without acoustic wave processing. The enhanced cyclone separation test study for acoustic agglomerated particles has provided a technical basis for pressurized fluid bed combustion(PFBC) application.展开更多
Magnetic seeding agglomeration(MSA),i.e.,adding magnetic seeds and a low intensity pre-magnetization for fine agglomeration,was applied to the flotation of coal,pyrite and hematite ore slimes.Size analysis and flotati...Magnetic seeding agglomeration(MSA),i.e.,adding magnetic seeds and a low intensity pre-magnetization for fine agglomeration,was applied to the flotation of coal,pyrite and hematite ore slimes.Size analysis and flotation tests highlight that the MSA improved flotation recovery and kinetics of pyrite ore while causing some loss in selectivity,and in the presences of the polyacrylamide for coal and starch for hematite the agglomeration flotation was further strengthened due to the synergetic effect between the flocculants and magnetic seeds.Magnetism analyses and calculation confirmed the adsorption of magnetic seeds onto minerals,resulting in a decreased threshold magnetic field intensity for the MSA to happen.Then atomic force microscope(AFM)study found that there exists a long range force between magnetic seeds and minerals,which facilitates the adsorption of magnetic seeds on minerals.FTIR shows both the polyacrylamide and starch adsorbed onto minerals and magnetic seeds,thus acting as the bridging media between minerals and magnetic seeds,intensifying the agglomeration in flotation.Surface characterization of the MSA was understood by SEM imaging,and models of the MSA were proposed.展开更多
Behavior of catalytic cracking reactions of particle cluster in fluid catalytic cracking (FCC) riser reactors was numerically analyzed using a four-lump mathematical model. Effects of the cluster porosity, inlet gas...Behavior of catalytic cracking reactions of particle cluster in fluid catalytic cracking (FCC) riser reactors was numerically analyzed using a four-lump mathematical model. Effects of the cluster porosity, inlet gas velocity and temperature, and coke deposition on cracking reactions of the cluster were investigated. Distributions of temperature, gases, and gasoline from both catalyst particle cluster and an isolated catalyst particle are presented. The reaction rates from vacuum gas oil (VGO) to gasoline, gas and coke of individual particle in the cluster are higher than those of the isolated particle, but it reverses for the reaction rates from gasoline to gas and coke. Less gasoline is produced by particle clustering. Simulated results show that the produced mass fluxes of gas and gasoline increase with the operating temperature and molar concentration of VGO, and decrease due to the formation of coke.展开更多
We present two schemes for preparing cluster states with atomic qubits in an ion-trap system. In the first scheme an auxiliary atomic level is needed. While in the second scheme an additional classical driven field is...We present two schemes for preparing cluster states with atomic qubits in an ion-trap system. In the first scheme an auxiliary atomic level is needed. While in the second scheme an additional classical driven field is used, and the multi-ion cluster states can be generated by one step. Both the schemes are insensitive to thermal motion of the ions, all the facilities used in them are well within state of the art.展开更多
The Williamson-Hall and uniaxial compression methods were used to study the variations of the micro-strain and stress-strain relations in WC powders after jet milling and ball milling, respectively. The rupture behavi...The Williamson-Hall and uniaxial compression methods were used to study the variations of the micro-strain and stress-strain relations in WC powders after jet milling and ball milling, respectively. The rupture behavior of agglomerates in WC powders was investigated. Meanwhile, the as-obtained WC powders treated by different milling methods were used to fabricate WC-10%Co cemented carbides, followed by the performance assessment of cemented carbides. The results show that the micro-strain of the jet-milled WC powders decreases significantly compared with that of the ball-milled WC powders, and that the cemented carbides prepared by jet-milled WC powders exhibit excellent properties with a transverse-rupture strength of 4260 MPa, due to the elimination of agglomerates and the reduction of lattice strain.展开更多
The hydrophobic flocculation flotation of rutile fines in the presence of styryl phosphonic acid(SPA) was investigated by flotation tests, zeta-potential measurement, optical microscope observation, laser-based part...The hydrophobic flocculation flotation of rutile fines in the presence of styryl phosphonic acid(SPA) was investigated by flotation tests, zeta-potential measurement, optical microscope observation, laser-based particle size analysis, adsorption measurements and DLVO theory. The flotation tests indicated that rutile fines could be flocculated by SPA, and pH, shear force(stirring speed) and stirring time played significant roles in flocculation. The isoelectric point(IEP) and zeta-potential in whole range all moved to negative values as SPA was added according to the results from zeta-potential measurement. It was demonstrated that the primary reason for above was chemical adsorption. The laser-based particle size results showed the particle size at a stirring speed of 1800 r/min and 1000 mg/L SPA was the largest in all experiments. Furthermore, using the optical microscope observation and flotation tests, it was important for flotation of rutile fines to produce the flocculant. In the light of above-mentioned facts, floc flotation of rutile fines could be induced in the form of chemical adsorption by SPA to increase particle size. The data calculated from DLVO theory also indicated that chemical adsorption was the main reason for the formation of flocculant.展开更多
The water stability of aggregates in various size classes separated from 18 samples of red soils under different managements, and the mechanisms responsible for the formation of water-stable soil aggregates were studi...The water stability of aggregates in various size classes separated from 18 samples of red soils under different managements, and the mechanisms responsible for the formation of water-stable soil aggregates were studied. The results showed that the water stability of soil aggregates declined with increasing size, especially for the low organic matter soils. Organic matter plays a key role in the formation of water-stable soil aggregates. The larger the soil aggregate size, the greater the impact of organic matter on the water stability of soil aggregates. Removal of organic matter markedly disintegrated the large water-stable aggregates (> 2.0 mm) and increased the small ones (< 0.25-0.smm) to some extent, whereas removal of free iron(aluminium) oxides considerably destroyed aggregates of all sizes, especially the < 0.25-0.5 mm classes. The contents of organic matter in water-stable aggregates increased with aggregate sizes. It is concluded from this study that small water-stable aggregates (< 0.25-0.5 mm) were chiefly cemented by Fe and Al oxides whilst the large ones (> 2.0 mm) were mainly glued up by organic matter. Both free oxides and organic matter contribute to the formation and water stability of aggregates in red soils.展开更多
The present study evaluated the effect of feed particle size, thermal processing, several levels of fat inclusion and moisture addition on pellet quality and protein solubility in potassium hydroxide (KOH) in a corn...The present study evaluated the effect of feed particle size, thermal processing, several levels of fat inclusion and moisture addition on pellet quality and protein solubility in potassium hydroxide (KOH) in a corn, soybean meal and animal by products based broiler diets. The different processing factors were combined in a 2 x 4 x 4 x 2 factorial arrangement in an eight randomized block consisting of eight production series: two particle sizes (coarse: 1,041 microns and medium: 743 microns), four fat inclusion levels at the mixer (15, 25, 35 and 45 g/kg of feed), four moisture addition levels in the conditioner (0, 7, 14 and 21 g/kg of feed) and two thermal processing treatments (conditioner-pellet press treatment or conditioner-expander-pellet treatment) which resulted in 64 different processed feeds. For the determination of the pellet durability index (PDI), the amount of intact pellets and protein solubility determinations, eight feed samples (replicates) were collected for each treatment. The data were transformed using a variation of Box-Cox transformation in order to fit a normal distribution (p 〉 0.05). Adding moisture up to 21 g/kg of feed in the conditioner improved pellet quality of the diets (p 〈 0.05). Expansion of diets before pelleting improved (P 〈 0.05) PDI and amount of intact pellets by 26% and 31%, respectively, as compared to a simple conditioning-pelleting feed processing. Expander treatment (at 110 ℃) decreased (p 〈 0.05) protein solubility in KOH from 686 g/kg to 643 g/kg total protein as compared to pelleting process (at 80-82 ℃). The amount of intact pellets reduced from 773 g/kg to 746 g/kg of feed (/7 〈 0.05) as particle size increased from medium to coarse grinding. Pellet quality was significantly reduced with fat inclusion levels higher than 35 g/kg of diet.展开更多
Oriented aggregation of nanoparticles has been accomplished by means of solid state reac- tion. Non-crystallized and crystallized ZnO nanoparticles/clusters could be accommodated in the lamellar spacing of inorganic-o...Oriented aggregation of nanoparticles has been accomplished by means of solid state reac- tion. Non-crystallized and crystallized ZnO nanoparticles/clusters could be accommodated in the lamellar spacing of inorganic-organic composite, which were prepared by thermolysis of layered solid zinc-oleate complex at 260 and 300 ℃ in air, respectively. High-resolution transmission electron microscopy and selected area electron diffraction patterns indicate that aggregates are single crystals with various defects. The photoluminescence excitation spectra of both samples show two bands at 272 and 366 nm. The former may originate from electron transfer from valence band to conduction band in ZnO clusters composed of less than 200 ZnO molecules (2R〈2 nm).展开更多
The flash points of organic compounds were estimated using a hybrid method that includes a simple group contribution method (GCM) implemented in an artificial neural network (ANN) with particle swarm optimization (PSO...The flash points of organic compounds were estimated using a hybrid method that includes a simple group contribution method (GCM) implemented in an artificial neural network (ANN) with particle swarm optimization (PSO). Different topologies of a multilayer neural network were studied and the optimum architecture was determined. Property data of 350 compounds were used for training the network. To discriminate different substances the molecular structures defined by the concept of the classical group contribution method were given as input variables. The capabilities of the network were tested with 155 substances not considered in the training step. The study shows that the proposed GCM+ANN+PSO method represent an excellent alternative for the estimation of flash points of organic compounds with acceptable accuracy (AARD = 1.8%; AAE = 6.2 K).展开更多
Coverage challenge for small considered to be a optlmlzation is a main cell clusters which are promising solution to provide seamless cellular coverage for large indoor or outdoor areas. This paper focuses on small ce...Coverage challenge for small considered to be a optlmlzation is a main cell clusters which are promising solution to provide seamless cellular coverage for large indoor or outdoor areas. This paper focuses on small cell cluster coverage problems and proposes both centralized and distributed self-optimization methods. Modified Particle swarm optimization (MPSO) is introduced to centralized optimization which employs particle swarm optimization (PSO) and introduces a heuristic power control scheme to accelerate the algorithm to search tbr the global optimum solution. Distributed coverage optimization is modeled as a non-cooperative game, with a utility function considering both throughput and interference. An iterative power control algorithm is then proposed using game theory (DGT) which converges to Nash Equilibrium (NE). Simulation results show that both MPSO and DGT have excellent performance in coverage optimization and outperform optimization using simulated annealing algorithm (SA), reaching higher coverage ratio and throughput while with less iterations.展开更多
This paper deals with characteristics of organo-mineral complexing of microaggregates in the paddy soils developed from purple soils in Sichuan, China. Results show that the contents of organic matter in microaggregat...This paper deals with characteristics of organo-mineral complexing of microaggregates in the paddy soils developed from purple soils in Sichuan, China. Results show that the contents of organic matter in microaggregates are in the order of 1--0.25 mm > smaller than 0.05 mm > 0.05-0.25 mm. But the organic matter in 1-0.01 mm microaggregates accounts for 68.1%-78.7% of that in soil. The organic matter in<0.05 mm microaggregates is complexed humus on the whole, of which the degree of organo-mineral complexing varies between 96.1% and 99.5%, which is higher than that of the soil or>0.05 mm microaggregates. The contents of loosely combined humus and the ratios of loosely and tightly combined humus markedly decline with the size of microaggregates. Fresh soil humus formed from semi-decomposed organic material or organic manure added is combined first with<0.001 mm clay, and then aggregated with other organic and mineral particles to form larger microaggregates, in which the aging of humus happens at the same time; whereas organic matter of the light fraction is mainly involved in the formation of>0.05 mm microaggregates.展开更多
In this work, we proposed a novel three-dimensional (3D) plasmonic nanostructure based on porous graphene/nickel foam (GNF) and gas-phase deposited Ag nanoparticles (NPs). Ag NPs with high density were directly deposi...In this work, we proposed a novel three-dimensional (3D) plasmonic nanostructure based on porous graphene/nickel foam (GNF) and gas-phase deposited Ag nanoparticles (NPs). Ag NPs with high density were directly deposited on the surface of 3D GNF by performing a novel cluster beam deposition approach. In comparison with traditional Ag substrate (SiO2/Ag), such hot-spots enriched 3D nanostructure showed extremely high electromag-netic field enhancement under incident light irradiation which could be used as a sensitive chemical sensor based on surface enhanced Raman scattering (SERS). The experimental results demonstrated that the proposed nanostructure showed superior SERS performance in terms of Raman signal reproducibility and sensitivity for the probe molecules. 3D full-wave simulation showed that the enhanced SERS performance in this 3D hierarchical plasmonic nanostructure was mainly obtained from the hot-spots between Ag NPs and the near-field coupling between Ag NPs and GNF sca olds. This work can provide a novel assembled SERS substrate as a SERS-based chemical sensor in practical applications.展开更多
We present a one-dimensional dynamic model of polydisperse granular mixture with the fractal characteristic of the particle size distribution, in which the particles are subject to inelastic mutual collisions and are ...We present a one-dimensional dynamic model of polydisperse granular mixture with the fractal characteristic of the particle size distribution, in which the particles are subject to inelastic mutual collisions and are driven by Gaussian white noise. The inhomogeneity of the particle size distribution is described by a fractal dimension D. The stationary state that the mixture reaches is the result of the balance between energy dissipation and energy injection. By molecular dynamics simulations, we have mainly studied how the inhomogeneity of the particle size distribution and the inelasticity of collisions influence the velocity distribution and distribution of interparticle spacing in the steady-state. The simulation results indicate that, in the inelasticity case, the velocity distribution strongly deviates from the Gaussian one and the system has a strong spatial clustering. Thus the inhomogeneity and the inelasticity have great effacts on the velocity distribution and distribution of interparticle spacing. The quantitative information of the non-Gaussian velocity distribution and that of clustering are respectively represented.展开更多
Aminopropyl, ethylenediamine, ethenyl and glycidoxy groups functionalized nanoparticles, with average diameters ranging from 4 to 6 nm and containing 1.17mmol of groups/g, are readily obtained from nanodiamonds modifi...Aminopropyl, ethylenediamine, ethenyl and glycidoxy groups functionalized nanoparticles, with average diameters ranging from 4 to 6 nm and containing 1.17mmol of groups/g, are readily obtained from nanodiamonds modified with silane coupling agent. For the study of these nanoparticles, TEM, IRS, XPS, and TG analysis methods have been used.展开更多
It has been possible to pelletize wood Miscanthus mixtures (12.5%, 25% and 50%) without modifying production process settings of a softwood pellets plant. Pure Miscanthus material tested in the same conditions has l...It has been possible to pelletize wood Miscanthus mixtures (12.5%, 25% and 50%) without modifying production process settings of a softwood pellets plant. Pure Miscanthus material tested in the same conditions has led to unstable production, mainly explained by hammermill overfeeding. The unstable production has been identified as the main responsible factor of the low quality of pellets produced with pure Miscanthus for these trials. The produced pellets were tested in a 25 kW boiler and compared with agro-pellets of various origins: winter barley straw, rapeseed straw, reed, old hay, Miscanthus, and wood pellets. Results gained during these combustion trials allowed to describe combustion of these uncommon fuels and to characterize its emissions. The trials confirm general characteristics of agricultural fuel combustion: influence of the ash content on the gross calorific value, influence of the N content in the fuel on the NOx emissions, influence on the alkali content on the C12 emissions. But the influence of known parameter (S. alkali and earth alkali content) on SO2 emission might not be highlighted, while a relation with the fuel moisture content could be considered.展开更多
基金Project(DUT15JJ(G)01) supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2009AA03Z525) supported by the National High-tech Research and Development Program of China
文摘A novel A1-Ti-C master alloy containing A14C3 and TiC particle clusters, which exhibits great refining potential for Mg, was prepared. With the addition of 2% A1-Ti-C master alloy, the grains transform to equiaxed crystal with a diameter of (110-a:17) ~tm. The results indicate that A14C3 and TiC particle cluster, rather than a single particle, plays an important role in the refining process. Compared with the simplex smooth nucleating substrate, concave regions on the particle cluster provide easier route for the transformation from liquid Mg atoms to stable nucleus. Nucleus with a small size can also reach the critical nucleation radius when they attach on the concave regions of the substrate. A14C3 and TiC particle clusters thus become more favorable nucleating substrate for a-Mg grains.
文摘The magnetization curves of MnFe2O4 nanoparticles and self-formed ferrofluids based on these particles have been measured at room temperature. The median size of the particles is 13.67 nm. The specific saturation magnetization is less than the theoretical value for the ferrofluids. In the high field range from 5 kOe to 10 kOe, the higher the particle volume fraction is, the steeper the slope of the magnetization curves is when it approaches saturation. The behavior of the saturation magnetization and the law of approach to saturation are due to the presence of self-assembled aggregates of ring-like micelle structures which form in the absence of the magnetic field and field-induced aggregates, respectively. The field-induced aggregates have a dissipative structure, so that at high field, the law of approach to saturation magnetization is different from the one described using Langevin paramagnetism theory. The large particles in the ferrofluids result in apparent hysteresis.
文摘To test the particles solidity and to verify the separating efficiency at normal atmospheric temperature, the experimental research was made on the enhanced cyclone separation of acoustic agglomerated fly ash particles. The separating efficiency has increased by 3%-4% in a sound field with 150 dB pressure level compared with that obtained without acoustic wave processing. The enhanced cyclone separation test study for acoustic agglomerated particles has provided a technical basis for pressurized fluid bed combustion(PFBC) application.
基金Project(51274256)supported by the National Natural Science Foundation of China
文摘Magnetic seeding agglomeration(MSA),i.e.,adding magnetic seeds and a low intensity pre-magnetization for fine agglomeration,was applied to the flotation of coal,pyrite and hematite ore slimes.Size analysis and flotation tests highlight that the MSA improved flotation recovery and kinetics of pyrite ore while causing some loss in selectivity,and in the presences of the polyacrylamide for coal and starch for hematite the agglomeration flotation was further strengthened due to the synergetic effect between the flocculants and magnetic seeds.Magnetism analyses and calculation confirmed the adsorption of magnetic seeds onto minerals,resulting in a decreased threshold magnetic field intensity for the MSA to happen.Then atomic force microscope(AFM)study found that there exists a long range force between magnetic seeds and minerals,which facilitates the adsorption of magnetic seeds on minerals.FTIR shows both the polyacrylamide and starch adsorbed onto minerals and magnetic seeds,thus acting as the bridging media between minerals and magnetic seeds,intensifying the agglomeration in flotation.Surface characterization of the MSA was understood by SEM imaging,and models of the MSA were proposed.
基金Supported by the National Natural Science Foundation of China (50776023) and NSFC-Petro China (20490200).
文摘Behavior of catalytic cracking reactions of particle cluster in fluid catalytic cracking (FCC) riser reactors was numerically analyzed using a four-lump mathematical model. Effects of the cluster porosity, inlet gas velocity and temperature, and coke deposition on cracking reactions of the cluster were investigated. Distributions of temperature, gases, and gasoline from both catalyst particle cluster and an isolated catalyst particle are presented. The reaction rates from vacuum gas oil (VGO) to gasoline, gas and coke of individual particle in the cluster are higher than those of the isolated particle, but it reverses for the reaction rates from gasoline to gas and coke. Less gasoline is produced by particle clustering. Simulated results show that the produced mass fluxes of gas and gasoline increase with the operating temperature and molar concentration of VGO, and decrease due to the formation of coke.
基金The project supported by the Scientific Research Fund of the Education Department of Hunan Province under Grant No.06C354the Natural Science Foundation of Hunan Province under Grant No.06JJ5015
文摘We present two schemes for preparing cluster states with atomic qubits in an ion-trap system. In the first scheme an auxiliary atomic level is needed. While in the second scheme an additional classical driven field is used, and the multi-ion cluster states can be generated by one step. Both the schemes are insensitive to thermal motion of the ions, all the facilities used in them are well within state of the art.
基金Project(2016GZ0290) supported by the Key Technology R&D Program of Sichuan Province,ChinaProject(2019CDXYCL0031) supported by the Fundamental Research Funds for the Central Universities,China
文摘The Williamson-Hall and uniaxial compression methods were used to study the variations of the micro-strain and stress-strain relations in WC powders after jet milling and ball milling, respectively. The rupture behavior of agglomerates in WC powders was investigated. Meanwhile, the as-obtained WC powders treated by different milling methods were used to fabricate WC-10%Co cemented carbides, followed by the performance assessment of cemented carbides. The results show that the micro-strain of the jet-milled WC powders decreases significantly compared with that of the ball-milled WC powders, and that the cemented carbides prepared by jet-milled WC powders exhibit excellent properties with a transverse-rupture strength of 4260 MPa, due to the elimination of agglomerates and the reduction of lattice strain.
基金Projects(51474254,51774332,51320105006) supported by the National Natural Science Foundation of ChinaProject(NCET-13-0595) supported by the Program for New Century Excellent Talents in University,ChinaProjects(2017zzts579,2017zzts379) supported by the Fundamental Research Funds for the Central Universities of China
文摘The hydrophobic flocculation flotation of rutile fines in the presence of styryl phosphonic acid(SPA) was investigated by flotation tests, zeta-potential measurement, optical microscope observation, laser-based particle size analysis, adsorption measurements and DLVO theory. The flotation tests indicated that rutile fines could be flocculated by SPA, and pH, shear force(stirring speed) and stirring time played significant roles in flocculation. The isoelectric point(IEP) and zeta-potential in whole range all moved to negative values as SPA was added according to the results from zeta-potential measurement. It was demonstrated that the primary reason for above was chemical adsorption. The laser-based particle size results showed the particle size at a stirring speed of 1800 r/min and 1000 mg/L SPA was the largest in all experiments. Furthermore, using the optical microscope observation and flotation tests, it was important for flotation of rutile fines to produce the flocculant. In the light of above-mentioned facts, floc flotation of rutile fines could be induced in the form of chemical adsorption by SPA to increase particle size. The data calculated from DLVO theory also indicated that chemical adsorption was the main reason for the formation of flocculant.
文摘The water stability of aggregates in various size classes separated from 18 samples of red soils under different managements, and the mechanisms responsible for the formation of water-stable soil aggregates were studied. The results showed that the water stability of soil aggregates declined with increasing size, especially for the low organic matter soils. Organic matter plays a key role in the formation of water-stable soil aggregates. The larger the soil aggregate size, the greater the impact of organic matter on the water stability of soil aggregates. Removal of organic matter markedly disintegrated the large water-stable aggregates (> 2.0 mm) and increased the small ones (< 0.25-0.smm) to some extent, whereas removal of free iron(aluminium) oxides considerably destroyed aggregates of all sizes, especially the < 0.25-0.5 mm classes. The contents of organic matter in water-stable aggregates increased with aggregate sizes. It is concluded from this study that small water-stable aggregates (< 0.25-0.5 mm) were chiefly cemented by Fe and Al oxides whilst the large ones (> 2.0 mm) were mainly glued up by organic matter. Both free oxides and organic matter contribute to the formation and water stability of aggregates in red soils.
文摘The present study evaluated the effect of feed particle size, thermal processing, several levels of fat inclusion and moisture addition on pellet quality and protein solubility in potassium hydroxide (KOH) in a corn, soybean meal and animal by products based broiler diets. The different processing factors were combined in a 2 x 4 x 4 x 2 factorial arrangement in an eight randomized block consisting of eight production series: two particle sizes (coarse: 1,041 microns and medium: 743 microns), four fat inclusion levels at the mixer (15, 25, 35 and 45 g/kg of feed), four moisture addition levels in the conditioner (0, 7, 14 and 21 g/kg of feed) and two thermal processing treatments (conditioner-pellet press treatment or conditioner-expander-pellet treatment) which resulted in 64 different processed feeds. For the determination of the pellet durability index (PDI), the amount of intact pellets and protein solubility determinations, eight feed samples (replicates) were collected for each treatment. The data were transformed using a variation of Box-Cox transformation in order to fit a normal distribution (p 〉 0.05). Adding moisture up to 21 g/kg of feed in the conditioner improved pellet quality of the diets (p 〈 0.05). Expansion of diets before pelleting improved (P 〈 0.05) PDI and amount of intact pellets by 26% and 31%, respectively, as compared to a simple conditioning-pelleting feed processing. Expander treatment (at 110 ℃) decreased (p 〈 0.05) protein solubility in KOH from 686 g/kg to 643 g/kg total protein as compared to pelleting process (at 80-82 ℃). The amount of intact pellets reduced from 773 g/kg to 746 g/kg of feed (/7 〈 0.05) as particle size increased from medium to coarse grinding. Pellet quality was significantly reduced with fat inclusion levels higher than 35 g/kg of diet.
文摘Oriented aggregation of nanoparticles has been accomplished by means of solid state reac- tion. Non-crystallized and crystallized ZnO nanoparticles/clusters could be accommodated in the lamellar spacing of inorganic-organic composite, which were prepared by thermolysis of layered solid zinc-oleate complex at 260 and 300 ℃ in air, respectively. High-resolution transmission electron microscopy and selected area electron diffraction patterns indicate that aggregates are single crystals with various defects. The photoluminescence excitation spectra of both samples show two bands at 272 and 366 nm. The former may originate from electron transfer from valence band to conduction band in ZnO clusters composed of less than 200 ZnO molecules (2R〈2 nm).
文摘The flash points of organic compounds were estimated using a hybrid method that includes a simple group contribution method (GCM) implemented in an artificial neural network (ANN) with particle swarm optimization (PSO). Different topologies of a multilayer neural network were studied and the optimum architecture was determined. Property data of 350 compounds were used for training the network. To discriminate different substances the molecular structures defined by the concept of the classical group contribution method were given as input variables. The capabilities of the network were tested with 155 substances not considered in the training step. The study shows that the proposed GCM+ANN+PSO method represent an excellent alternative for the estimation of flash points of organic compounds with acceptable accuracy (AARD = 1.8%; AAE = 6.2 K).
基金supported by the National High-Tech Development 863 Program of China (Grant DOS. 2012AA012801)National Natural Science Foundation of China(No.61331009)
文摘Coverage challenge for small considered to be a optlmlzation is a main cell clusters which are promising solution to provide seamless cellular coverage for large indoor or outdoor areas. This paper focuses on small cell cluster coverage problems and proposes both centralized and distributed self-optimization methods. Modified Particle swarm optimization (MPSO) is introduced to centralized optimization which employs particle swarm optimization (PSO) and introduces a heuristic power control scheme to accelerate the algorithm to search tbr the global optimum solution. Distributed coverage optimization is modeled as a non-cooperative game, with a utility function considering both throughput and interference. An iterative power control algorithm is then proposed using game theory (DGT) which converges to Nash Equilibrium (NE). Simulation results show that both MPSO and DGT have excellent performance in coverage optimization and outperform optimization using simulated annealing algorithm (SA), reaching higher coverage ratio and throughput while with less iterations.
文摘This paper deals with characteristics of organo-mineral complexing of microaggregates in the paddy soils developed from purple soils in Sichuan, China. Results show that the contents of organic matter in microaggregates are in the order of 1--0.25 mm > smaller than 0.05 mm > 0.05-0.25 mm. But the organic matter in 1-0.01 mm microaggregates accounts for 68.1%-78.7% of that in soil. The organic matter in<0.05 mm microaggregates is complexed humus on the whole, of which the degree of organo-mineral complexing varies between 96.1% and 99.5%, which is higher than that of the soil or>0.05 mm microaggregates. The contents of loosely combined humus and the ratios of loosely and tightly combined humus markedly decline with the size of microaggregates. Fresh soil humus formed from semi-decomposed organic material or organic manure added is combined first with<0.001 mm clay, and then aggregated with other organic and mineral particles to form larger microaggregates, in which the aging of humus happens at the same time; whereas organic matter of the light fraction is mainly involved in the formation of>0.05 mm microaggregates.
基金supported by the National Natural Science Foundation of China (No.11604161)the Natural Science Foundation of Jiangsu Province (No.BK20160914)+2 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (No.16KJB140009)the Foundation from Nanjing University of Posts and Telecommunication (No.NY216012)the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sk lodowska-Curie Grant (No.752102)
文摘In this work, we proposed a novel three-dimensional (3D) plasmonic nanostructure based on porous graphene/nickel foam (GNF) and gas-phase deposited Ag nanoparticles (NPs). Ag NPs with high density were directly deposited on the surface of 3D GNF by performing a novel cluster beam deposition approach. In comparison with traditional Ag substrate (SiO2/Ag), such hot-spots enriched 3D nanostructure showed extremely high electromag-netic field enhancement under incident light irradiation which could be used as a sensitive chemical sensor based on surface enhanced Raman scattering (SERS). The experimental results demonstrated that the proposed nanostructure showed superior SERS performance in terms of Raman signal reproducibility and sensitivity for the probe molecules. 3D full-wave simulation showed that the enhanced SERS performance in this 3D hierarchical plasmonic nanostructure was mainly obtained from the hot-spots between Ag NPs and the near-field coupling between Ag NPs and GNF sca olds. This work can provide a novel assembled SERS substrate as a SERS-based chemical sensor in practical applications.
基金The project supported by National Natural Science Foundation of China under Grant No. 10675048 and Natural Science Foundation of Xianning College under Grant No. KZ0627
文摘We present a one-dimensional dynamic model of polydisperse granular mixture with the fractal characteristic of the particle size distribution, in which the particles are subject to inelastic mutual collisions and are driven by Gaussian white noise. The inhomogeneity of the particle size distribution is described by a fractal dimension D. The stationary state that the mixture reaches is the result of the balance between energy dissipation and energy injection. By molecular dynamics simulations, we have mainly studied how the inhomogeneity of the particle size distribution and the inelasticity of collisions influence the velocity distribution and distribution of interparticle spacing in the steady-state. The simulation results indicate that, in the inelasticity case, the velocity distribution strongly deviates from the Gaussian one and the system has a strong spatial clustering. Thus the inhomogeneity and the inelasticity have great effacts on the velocity distribution and distribution of interparticle spacing. The quantitative information of the non-Gaussian velocity distribution and that of clustering are respectively represented.
基金Chinese Ministry of Education Doctor Fund No.: 2000055804.
文摘Aminopropyl, ethylenediamine, ethenyl and glycidoxy groups functionalized nanoparticles, with average diameters ranging from 4 to 6 nm and containing 1.17mmol of groups/g, are readily obtained from nanodiamonds modified with silane coupling agent. For the study of these nanoparticles, TEM, IRS, XPS, and TG analysis methods have been used.
文摘It has been possible to pelletize wood Miscanthus mixtures (12.5%, 25% and 50%) without modifying production process settings of a softwood pellets plant. Pure Miscanthus material tested in the same conditions has led to unstable production, mainly explained by hammermill overfeeding. The unstable production has been identified as the main responsible factor of the low quality of pellets produced with pure Miscanthus for these trials. The produced pellets were tested in a 25 kW boiler and compared with agro-pellets of various origins: winter barley straw, rapeseed straw, reed, old hay, Miscanthus, and wood pellets. Results gained during these combustion trials allowed to describe combustion of these uncommon fuels and to characterize its emissions. The trials confirm general characteristics of agricultural fuel combustion: influence of the ash content on the gross calorific value, influence of the N content in the fuel on the NOx emissions, influence on the alkali content on the C12 emissions. But the influence of known parameter (S. alkali and earth alkali content) on SO2 emission might not be highlighted, while a relation with the fuel moisture content could be considered.