Modeling continuous traffic flow with the average velocity effect of multiple vehicles ahead on gyroidal roads

In the future connected vehicle environment,the information of multiple vehicles ahead can be readily collected in real-time,such as the velocity or headway,which provides more opportunities for information exchange and cooperative control.Meanwhile,gyroidal roads are one of the fundamental road patterns prevalent in mountainous areas.To effectively control the system,it is therefore significant to explore the evolution mechanism of traffic flow on gyroidal roads under a connected vehicle environment.In this paper,we present a new continuum model with the average velocity of multiple vehicles ahead on gyroidal roads.The stability criterion and KdV-Burger equation are deduced via linear and nonlinear stability analysis,respectively.Solving the above KdV-Burger equation yields the density wave solution,which explores the formation and propagation property of traffic jams near the neutral stability curve.Simulation examples verify that the model can reproduce complex phenomena,such as shock waves and rarefaction waves.The analysis of the local cluster effect shows that the number of vehicles ahead and the radius information,and the slope information of gyroidal roads can exert a great influence on traffic jams.The effect of the first and second terms are positive,while the last term is negative.

均一与梯度孔隙率Gyroid结构力学性能研究及多孔种植体增材制造

目的研究不同孔隙率及梯度孔隙率Gyroid结构力学性能,设计并制备新型多孔种植体。方法通过MSLattice和Magics软件建立均一孔隙率为60%、65%、70%、75%、80%和60%~80%梯度的Gyroid结构模型,分别通过有限元分析及力学压缩试验对比不同孔隙率Gyroid结构力学性能,设计并通过激光选区熔融技术(selective laser melting,SLM)3D打印新型多孔种植体。结果随着孔隙率的上升,Gyroid结构的弹性模量和抗压强度下降。同一孔隙率下,SLA前后Gyroid结构的弹性模量差异不具有统计学显著性(P>0.05),梯度Gyroid结构的最大抗压应变均低于各均一孔隙率Gyroid结构。结论梯度Gyroid结构匹配了骨皮质及骨松质的弹性模量,且强度与人骨相近,具有优异的力学性能,有望应用在口腔种植体上。

3D打印梯度Gyroid结构的动态冲击响应

利用ANSYS/LS-DYNA对均匀及梯度Gyroid结构进行准静态与动态压缩数值模拟,分析其应力分布、变形模式、承载能力以及吸能特性。对3D打印的316L不锈钢试样实施了单轴拉伸实验,获取了相应的材料参数,建立了Gyroid结构有限元模型,进而对其动态力学响应进行了数值仿真。结果表明:均匀结构呈现出较均匀的变形模式,梯度结构为低密度端向高密度端传播的逐层变形模式;两种结构均呈现明显的应变率敏感性,且负梯度结构的应变率敏感性最明显;在相同的加载速度下,负梯度结构的吸能效率最高,且具有最低的支撑端应力,是最佳的防护结构。研究结果可为冲击载荷下防护结构的设计选型提供参考。

Feeding Effect of Codariocalyx gyroides on Meat Rabbits

To explore the feeding effect of Codariocalyx gyroides on meat rabbits, 30 healthy meat rabbits at the age of 50 days were randomly divided into five groups(Ⅰ,Ⅱ,Ⅲ,Ⅳ and Ⅴ), six rabbits each group. Rabbits in experimental groups Ⅰ,Ⅱ,Ⅲ and Ⅳ were fed with different quantita-tive complete formula feed and unlimited fresh grass of C. gyroides, and those in group Ⅴ(control group) were fed with complete formula feed. The indicators such as feed intake and growth performance were measured after 60 d. The results showed that the gaining effects of meat rabbits in ex-perimental groups Ⅳ and Ⅲ were most obvious, and the daily gain reached(25.75 ±3.00) and(24.50±1.95) g, 20.72% and 14.86% higher than those in control group, respectively. The conversion efficiency of dry matter in experimental group Ⅲ was the highest, and only 2.99 g of C. gyroides and compound feed dry matter was consumed for the growth of 1 g of rabbit meat, receiving significant economic benefit.

Ordered Bicontinuous Network Structures Regulated by Orientational Interactions in a Rod-Coil Block Copolymer

The rich phase behavior of block copolymers(BCPs)has drawn great attention in recent years.However,the double diamond(DD)phase is rarely obtained because of the competition between the minimization of interfacial energy and packing frustration.Here,a rod-coil BCP containing mesogen-jacketed liquid crystalline polymer is designed to acquire ordered bicontinuous network nanostructures.The reduction of internal energy originating from the orientational interaction among the rod blocks can compensate for the free energy penalty of packing frustration to stabilize the DD structure.The resulting BCP can also experience lamellae-to-DD and double gyroid-to-lamellae transitions by changing the annealing temperature.These results make the rod-coil BCP an excellent candidate for the self-assembly of ordered network structures,demonstrating great potential in nanopatterning and metamaterials.

Bragg-mirror-like circular dichroism in bio-inspired quadruple-gyroid 4srs nanostructures

The smooth and tailorable spectral response of Bragg mirrors has driven their pervasive use in optical systems requiring customizable spectral control of beam propagation.However,the simple nature of Bragg mirror reflection prevents their application to the control of important polarization states such as circular polarization.While helical and gyroid-based nanostructures exhibiting circular dichroism have been developed extensively to address this limitation,they are often restricted by the spectral inconsistency of their optical response.Here we present the fabrication and characterization of quadruple-gyroid 4srs nanostructures exhibiting bio-inspired Bragg-mirror-like circular dichroism:a smooth and uniform band of circular dichroism reminiscent of the spectrum of a simple multilayer Bragg-mirror.Furthermore,we demonstrate that the circular dichroism produced by 4srs nanostructures are robust to changes in incident angle and beam collimation,providing a new platform to create and engineer circular dichroism for functional circular polarization manipulation.

3D direct printing of mechanical and biocompatible hydrogel meta-structures

Direct Ink Writing(DIW)has demonstrated great potential as a versatile method to 3D print multifunctional structures.In this work,we report the implementation of hydrogel meta-structures using DIW at room temperature,which seamlessly integrate large specific surface areas,interconnected porous characteristics,mechanical toughness,biocompatibility,and water absorption and retention capabilities.Robust but hydrophobic polymers and weakly crosslinked nature-origin hydrogels form a balance in the self-supporting ink,allowing us to directly print complex meta-structures without sacrificial materials and heating extrusion.Mechanically,the mixed bending or stretching of symmetrical re-entrant cellular lattices and the unique curvature patterns are combined to provide little lateral expansion and large compressive energy absorbance when external forces are applied on the printed meta-structures.In addition,we have successfully demonstrated ear,aortic valve conduits and hierarchical architectures.We anticipate that the reported 3D meta-structured hydrogel would offer a new strategy to develop functional biomaterials for tissue engineering applications in the future.