CoS_(2)nanowires supported graphdiyne for highly efficient hydrogen evolution reaction

Transition metal sulfides are an important category for hydrogen evolution reaction(HER).However,only few edge unsaturated sulfurs functionalize as catalytic sites,which has dramatically limited the catalytic activity and stability.In this work,planar unsaturated sulfurs in(211)plane of the CoS_(2)nanowires have been successfully activated through constructing Graphdiyne-CoS_(2)heterojunction nanocomposites.The corresponding electrons transfer energy barriers for these planar unsaturated sulfurs have been significantly diminished,which are induced by the synergetic effects of the sp~1 hybridized carbons and unsaturated planar sulfurs.In addition,DFT simulations reveal the synergetic effects of the sp~1 hybridized carbons and unsaturated planar sulfurs can promote electron transfer kinetics of the key step,VolmerHeyrovsky step,of the reaction.As expected,the Graphdiyne-CoS_(2)heterojunction nanocomposites exhibit superior HER catalytic performance with low overpotential of 97 mV at 10 mA cm^(-2),and the Tafel slope of 56 mV dec^(-1).Furthermore,the heterojunction shows outstanding stability as well due to the pr tection of the Graphdiyne(GDY).The approach thus paves the way for the further efficient transition metal disulfides catalyst manufactures.

Changes in compressed neurons from dogs with acute and severe cauda equina constrictions following intrathecal injection of brain-derived neurotrophic factor-conjugated polymer nanoparticles

This study established a dog model of acute multiple cauda equina constriction by experimental constriction injury （48 hours） of the lumbosacral central processes in dorsal root ganglia neurons. The repair effect of intrathecal injection of brain-derived neurotrophic factor with 15 mg encapsulated biodegradable poly（lactide-co-glycolide） nanoparticles on this injury was then analyzed. Dorsal root ganglion cells （LT） of all experimental dogs were analyzed using hematoxylin-eosin staining and immunohistochemistry at 1,2 and 4 weeks following model induction. Intrathecal injection of brain-derived neurotrophic factor can relieve degeneration and inflammation, and elevate the expression of brain-derived neurotrophic factor in sensory neurons of compressed dorsal root ganglion Simultaneously, intrathecal injection of brain-derived neurotrophic factor obviously improved neurological function in the dog model of acute multiple cauda equina constriction. Results verified that sustained intraspinal delivery of brain-derived neurotrophic factor encapsulated in biodegradable nanoparticles promoted the repair of histomorphology and function of neurons within the dorsal root ganglia in dogs with acute and severe cauda equina syndrome.

A novel metal-ceramic composite combining the structures of nacre and nanofiber reinforced foam

Lightweight high-strength and tough composites have enormous potentials in a multitude of fields in-cluding biomaterials,sporting goods,aerospace and automobile industries.Herein,we present a strat-egy to develop a novel bulk Al/SiC composite with a nacre/foam hybrid structure to combine excellent lightweight of foams with outstanding strength and toughness of nacre.To reduce the adverse effect of foam pores on mechanical properties,we further propose to strengthen the foams with 3D nanofiber networks,obtaining a nacre/nanofiber reinforced foam structure.Simultaneously,new particle-bubble co-assembly and selective infiltration technologies are proposed to prepare the novel nacre/foam and nacre/nanofiber reinforced foam structures.The nacre/nanofiber reinforced foam composite shows greater specific strength and toughness than the nacre/foam composite,conventional dense Al/SiC composites and many engineering materials.Our approach opens a promising new avenue for the structure design and manufacturing of lightweight,high-performance structural materials.

TARGET AGGREGATION OF SECOND-ORDER MULTI-AGENT SYSTEMS WITH SWITCHING INTERCONNECTION

In this paper, the target aggregation is investigated for a multi-agent system consisting of second-order agents and multiple leaders. Sufficient conditions are proposed to make the agents approach the target set spanned by these moving leaders. With the condition on switching interconnection topologies, all mobile agents can asymptotically track the dynamical target set specified by multiple moving leaders with bounded error. Moreover, discussion on the case with static leaders is also given.

Design of multidimensional nanocomposite material to realize the application both in energy storage and electrocatalysis

The development of clean,sustainable and renewable energy storage systems is in urgent need with the fast-growing energy demand in the areas of electric vehicles and mobile electronics etc.Lithium-ion batteries(LIBs)have been deemed to be the most promising energy storage devices for their high power density,long cycle life and fast charge-discharge rates[1].Transition

Two-dimensional perovskite capping layer for stable and efficient tin-lead perovskite solar cells

Mixed tin-lead iodide perovskites exhibit the characteristics of low toxicity and improved light harvesting ability up to nearinfrared(NIR) spectral region, making them as an attractive alternative for traditional lead based perovskites. However, the performance of lead-based perovskites solar cells is still far inferior to their lead analogues owing to the unavoidable oxidation of Sn^(2+)to Sn^(4+). Here we introduced two-dimensional(2D) perovskite on the top of three dimensional(3D) perovskite film as a capping layer to reduce the self-oxidation, and thus improved the device stability. 2D capping layer was then confirmed by X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS) analysis. The existence of the 2D protecting thin layer significantly reduce the spontaneous Sn^(2+)oxidation, thus improve the device performance and reduce the hysteresis. The phenomena could be ascribed to the improved charge extraction efficiency causing by prohibited nonradiative recombination. On top of this, the photovoltaic devices based on conventional-structure configuration were fabricated. Taking advantage of the 2D capping layer, 2D/3D hybrid perovskite photovoltaic devices achieve a open-circuit voltage(Voc) of 0.77 V with short circuit current density(Jsc) of 26.60 mA cm^(-2), delivering the best-performing power conversion efficiency of 15.5%. Moreover, the 2D/3D perovskite devices maintained 60% its initial efficiency after 40 h exposed in air(humidity around 30%, temperature 22 °C),while 3D perovskite-based devices completely failed.