Embed-Solitons and Their Evolutional Behaviors of (3+1)-Dimensional Burgers System

With the help of an extended mapping approach and a linear variable separation method,new families ofvariable separation solutions with arbitrary functions for the(3+1)-dimensional Burgers system are derived.Based onthe derived exact solutions, some novel and interesting localized coherent excitations such as embed-solitons are revealedby selecting appropriate boundary conditions and/or initial qualifications.The time evolutional properties of the novellocalized excitation are also briefly investigated.

Evolution behavior and mechanism of iron carbon agglomerates under simulated blast furnace smelting conditions

Iron carbon agglomerates(ICA)are the composite burden for low-carbon blast furnace(BF)ironmaking.In order to optimize the reactivity of ICA according to the evolution characteristics of ICA in the BF smelting process,the evolution behavior and mechanism of different reactive ICA under simulated BF smelting conditions were studied.The results show that the existence of more sillimanite and aluminosilicate and less active sites of metallic iron will weaken gasification reaction and carburization ability of ICA-1(containing 10%iron ore).It weakens the promoting effect of ICA-1 on the reduction,softening,and melting of ferrous burdens and the dripping of slag-iron.The aluminosilicate with a high melting point decreases,the low melting point slag phase and Fe–Si alloy increase,and many active sites of metallic iron exist,which strengthen the gasification reaction and carburization ability of ICA-2(containing 30%iron ore).The promoting effect of ICA-2 on the reduction,softening,and melting of ferrous burdens and the dripping of slag-iron is significantly improved.The gasification reaction capacity of ICA-3(containing 35%iron ore)is reduced,and the improvement in ICA-3 on the softening–melting performance of mixed burdens is reduced.The appropriate proportion of iron ore in ICA is about 30%.

The damage evolution behavior of polypropylene fiber reinforced concrete subjected to sulfate attack based on acoustic emission

To study the damage evolution behavior of polypropylene fiber reinforced concrete(PFRC)subjected to sulfate attack,a uniaxial compression test was carried out based on acoustic emission(AE).The effect of sulfate attack relative to time and fiber hybridization were analyzed and the compression damage factor was calculated using a mathematical model.The changes to AE ringing counts during the compression could be divided into compaction,elastic,and AE signal hyperactivity stages.In the initial stage of sulfate attack,the concrete micropores and microcracks were compacted gradually under external load and a corrosion products filling effect,and this corresponded with detection of few AE signals and with concrete compression strength enhancement.With increasing sulfate attack time,AE activity decreased.The cumulative AE ringing counts of PFRC at all corrosion ages were much higher than those for plain concrete.PFRC could still produce AE signals after peak load due to drawing effect of polypropylene fiber.After 150 d of sulfate attack,the cumulative AE ringing counts of plain concrete went down by about an order of magnitude,while that for PFRC remained at a high level.The initial damage factor of hybrid PFRC was-0.042 and-0.056 respectively after 150 d of corrosion,indicating that the advantage of hybrid polypropylene fiber was more obvious than plain concrete and single-doped PFRC.Based on a deterioration equation,the corrosion resistance coefficient of hybrid PFRC would be less than 0.75 after 42 drying-wetting sulfate attack cycles,which was 40%longer than that of plain concrete.

Song variation of a native songbird in a modified habitat by invasive plant

Habitat structure has been considered as an important factor affecting the acoustic evolution of birds,and bird songs are increasingly affected by artificial environmental variation.Invasive plants sometimes can dramatically alter native habitats,but the song variation of native songbirds migrating into invaded habitats has received little attention.The invasion of smooth cordgrass Spartina alterniflora in the coastal wetlands of eastern China has drastically altered the vegetation structure and some small passerines have begun to use invaded habitats to breed.In this study,we compared the song type prevalence and the song characteristics of male plain prinia Prinia inornata to identify differences in vocal behavior between native and invaded habitats.We also tested for differences in vocal behavior in relation to singing perch and wind speed variation between different habitats.The results indicated that males of plain prinia in invaded habitats sang shorter songs than those in native habitats and had a lower song diversity.The homogeneous vegetation structure and higher wind speed in invaded habitats likely leads to males changing the traditional perched singing style.The song variation may be related to the founder effect,the alteration of vegetation structure and microclimate in invaded habitats.This finding highlights the need for better understanding the behavioral evolution of native species in the process of adapting to the invaded habitat.In the future,experimental manipulation is needed to ascertain how the invasive plant drove these vocal behavior changes of native songbirds.

Growth,coalescence,and etching of two-dimensional overlayers on metals modulated by near-surface Ar nanobubbles

The synthesis of high-quality ultrathin overlayers is critically dependent on the surface structure of substrates,especially involving the overlayer–substrate interaction.By using in situ surface measurements,we demonstrate that the overlayer–substrate interaction can be tuned by doping near-surface Ar nanobubbles.The interfacial coupling strength significantly decreases with near-surface Ar nanobubbles,accompanying by an“anisotropic to isotropic”growth transformation.On the substrate containing near-surface Ar,the growth front crosses entire surface atomic steps in both uphill and downhill directions with no difference,and thus,the morphology of the two-dimensional(2D)overlayer exhibits a round-shape.Especially,the round-shaped 2D overlayers coalesce seamlessly with a growth acceleration in the approaching direction,which is barely observed in the synthesis of 2D materials.This can be attributed to the immigration lifetime and diffusion rate of growth species,which depends on the overlayer–substrate interaction and the surface catalysis.Furthermore,the“round to hexagon”morphological transition is achieved by etching-regrowth,revealing the inherent growth kinetics under quasi-freestanding conditions.These findings provide a novel promising way to modulate the growth,coalescence,and etching dynamics of 2D materials on solid surfaces by adjusting the strength of overlayer–substrate interaction,which contributes to optimization of large-scale production of 2D material crystals.