Regulatable Orthotropic 3D Hybrid Continuous Carbon Networks for Efficient Bi-Directional Thermal Conduction

Vertically oriented carbon structures constructed from low-dimen-sional carbon materials are ideal frameworks for high-performance thermal inter-face materials(TIMs).However,improving the interfacial heat-transfer efficiency of vertically oriented carbon structures is a challenging task.Herein,an orthotropic three-dimensional(3D)hybrid carbon network(VSCG)is fabricated by depositing vertically aligned carbon nanotubes(VACNTs)on the surface of a horizontally oriented graphene film(HOGF).The interfacial interaction between the VACNTs and HOGF is then optimized through an annealing strategy.After regulating the orientation structure of the VACNTs and filling the VSCG with polydimethylsi-loxane(PDMS),VSCG/PDMS composites with excellent 3D thermal conductive properties are obtained.The highest in-plane and through-plane thermal conduc-tivities of the composites are 113.61 and 24.37 W m^(-1)K^(-1),respectively.The high contact area of HOGF and good compressibility of VACNTs imbue the VSCG/PDMS composite with low thermal resistance.In addition,the interfacial heat-transfer efficiency of VSCG/PDMS composite in the TIM performance was improved by 71.3%compared to that of a state-of-the-art thermal pad.This new structural design can potentially realize high-performance TIMs that meet the need for high thermal conductivity and low contact thermal resistance in interfacial heat-transfer processes.

Numerical study on three-dimensional flow field of continuously rotating detonation in a toroidal chamber

Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate chemistry. The results show that the calculated streak picture is in qualitative agreement with the picture recorded by a high speed streak camera from published literature. The three-dimensional flow field induced by a continuously rotating detonation was visualized and distinctive features of the rotating detonations were clearly depicted. Owing to the unconfined character of detonation wavelet, a deficit of detonation parameters was observed. Due to the effects of wall geometries, the strength of the outside detonation front is stronger than that of the inside portion. The detonation thus propagates with a constant circular velocity. Numerical simulation also shows three-dimensional rotating detonation structures, which display specific feature of the detonation- shock combined wave. Discrete burning gas pockets are formed due to instability of the discontinuity. It is believed that the present study could give an insight into the interest- ing properties of the continuously rotating detonation, and is thus beneficial to the design of continuous detonation propulsion systems.

Design and Construction Strategy of Arched Continuous Rigid-frame Bridge

With the current rapid development of urbanization in China,people's living standards have been greatly improved.In the context of such a development background,the requirements for road traffic are getting more stringent,especially for bridge projects.The arched continuous rigid-frame bridge was developed under this social background.The advantage of the bridge lies in the design of a bridge model that integrates various functions such as transportation,landscape,and sightseeing.Based on the above,this paper first refers to the case to analyze the design and construction strategy of the arched continuous rigid-frame bridge,in hope of providing a valuable reference for relevant personnel.

Continuous selections for pseudo-lower semicontinuous set-valued mappings on convex structure spaces and hyperspace contractibility

SINCE 1956, Michael’s continuous selection theory has been applied to functional analysis,topology, approximation theory and other mathematical fields. In this letter, the concept ofthe pseudo-lower semicontinuity is introduced, and a convex structure of metric space is de-fined. A continuous selection theorem for pseudo-lower semicontinuity is given. This

A novel high-strength Al-La-Mg-Mn alloy for selective laser melting

Developing high-strength Al-(La,Ce)alloys for additive manufacturing(AM)would entail considerable economic benefits.In this work,a novel near-eutectic Al-La alloy containing 5.50 wt.%Mg and 0.60 wt.%Mn was designed and fabricated via selective laser melting(SLM).Submicron Al_(11)La_(3)intermetallics with 3D continuous cellular-dendritic and granular morphologies were observed at the interior and boundary of the melt pool,respectively.Interestingly,these intermetallics are hierarchical and contained numerous Al_(6)Mn and Mg_(2)Si secondary nanoprecipitates.The as-fabricated alloy exhibited a tensile yield strength(YS)of 334 MPa and ultimate tensile strength(UTS)of 588 MPa at room temperature,which is the high-est UTS reported for Al-(La,Ce)alloys with an appreciable failure strain of∼6.4%.The 3D continuous cellular dendritic intermetallic and high Mg content afford significant strengthening and work harden-ing ability.In addition,the hierarchical feature of the intermetallics generated additional microcracks to coordinate the deformation.

Structural Stability of Weighted Digraph with Continuous Vertex Values

In this paper, we give a sufficient condition about the stability of weighted digraph, which exceeds Roberts original judgement extremely.

A SUFFICIENT CONDITION OF A POLYNOMIAL FISH POPULATION SYSTEM TO BE STABLE

In this paper,we use Lyapunov approach to study the stability of an exploited fish population system.The model considered is structured in n age classes and includes a nonlinear polynomial stock-recruitment relationship.Lyapunov candidate functions is investigated and sufficient conditions for global asymptotic stability of the studied polynomial system are proposed to allow computational implementation.The results obtained extend our previous study focusing on the solution to the same problem solved using other tools of control engineering.The advantage of the proposed approach is that the derived conditions proving the stability of the studied systems can be presented as in inequality in general and feasibility tests.The obtained results are tested by numerical examples.