摘要：Regulating the selectivity of catalysts in selective hydrogenation reactions at the atomic level is highly desirable but remains a grand challenge. Here we report a simple and practical strategy to synthesize a monolithic single-atom catalyst(SAC) with isolated Pd atoms supported on bulk nitrogen-doped carbon foams(Pd-SAs/CNF). Moreover, we demonstrate that the single-atom Pd sites with unique electronic structure endow Pd-SAs/CNF with an isolated site effect, leading to excellent activity and selectivity in 4-nitrophenylacetylene semi-hydrogenation reaction. In addition, benefiting from the great integrity and excellent mechanical strength, monolithic Pd-SAs/CNF catalyst is easy to separate from the reaction system for conducting the subsequent recycling. The cyclic test demonstrates the excellent reusability and stability of monolithic Pd-SAs/CNF *** discovery of isolated site effect provides a new approach to design highly selective catalysts. And the development of monolithic SACs provides new opportunities to advance the practical applications of single-atom catalysts.

摘要：In order to establish the constitutive relationship of high-ductility cementitious composites(HDCCs)under uniaxial tensile load and to guide the structural design of HDCCs,based on the analysis of the existing uniaxial tensile constitutive relationship and ideal elastoplastic linear strain-hardening model,a bilinear tensile constitutive equation of HDCCs was *** points of nominal initial cracking and nominal maximum stress were adopted as control points of the line segment,and the constitutive relationship of HDCCs was *** series of uniaxial tensile stress-strain curves of HDCCs were combined to perform an experimental application of the constitutive equation,along with an analysis of the key *** experimental results confirm the ability of the constitutive equation to overcome the problem of insufficient or excessive redundancy of existing models in terms of calculation bearing ***,the measured maximum stress value is larger than the nominal value,and the ratio between the two values ranges from 1.08 to ***,the tensile strain at the softening point obtained by fitting a straight line with the valley points of the strain-hardening stage curve is greater than or equal to the tensile strain at the measured maximum stress point and the ratio of the fitted values to the measured values ranges from 1.00 to 1.19.

摘要：Variable stiffness composite laminates(VSCLs)are promising in aerospace engineering due to their designable material properties through changing fiber angles and stacking *** to control the thermal postbuckling and nonlinear panel flutter motions of VSCLs,a full-order numerical model is developed based on the linear quadratic regulator(LQR)algorithm in control theory,the classical laminate plate theory(CLPT)considering von Kármán geometrical nonlinearity,and the first-order Piston *** critical buckling temperature and the critical aerodynamic pressure of VSCLs are parametrically *** location and shape of piezoelectric actuators for optimal control of the dynamic responses of VSCLs are determined through comparing the norms of feedback control gain(NFCG).Numerical simulations show that the temperature field has a great effect on aeroelastic tailoring of VSCLs;the curvilinear fiber path of VSCLs can significantly affect the optimal location and shape of piezoelectric actuator for flutter suppression;the unstable panel flutter and the thermal postbuckling deflection can be suppressed effectively through optimal design of piezoelectric patches.

摘要：Surface tailoring of Pt-based nanocatalysts is an effective pathway to promote their electrocatalytic performance and ***,we report two kinds of one-dimensional(1D)ultrafine PtCu nanowires(smooth surface&rugged surface)synthesized via a wet chemical method and their distinct catalytic performances in electro-oxidation of *** alloyed PtCu nanowires having rough surfaces with atomic steps exhibit superior catalytic activity toward multiple electrochemical reactions compared with the smooth *** functional theory simulations show the excellent reactivity of rugged PtCu na-nowires and attribute it to the surface synergetic Pt-Cu site which accounts for the promotion of water dissociation and the dehydrogenation of the carboxyl *** current study provides an insight into reasonable design of alloy nanocatalysts in energy-related electrocatalytic systems.

摘要：可被蓝光激发的高热稳定性红色荧光粉是制作高性能白光二极管(WLED)的关键材料.研究发现,Ce^(3+)掺杂的SrLaScO_(4)(SLO:Ce^(3+))荧光粉在440 nm激发下呈现峰值为640 nm的反常宽带红光发射.光谱学和结构分析证实Ce^(3+)离子在SLO中进入[LaO_(8)]多面体,产生强的晶体场劈裂和较大的Stokes位移,实现了比Eu^(2+)更低能量的红光发射.我们还设计并揭示了一种电荷转移相互作用的策略:在Sc^(3+)位置引入电负性较大的Ga^(3+),Ga^(3+)可以吸引更多邻位配合基团的电荷,以减少导带底部的电子占用而扩大带隙.Sc/Ga取代有效地抑制了热激活电离过程,使SrLa(Sc,Ga)O_(4):Ce^(3+)的热稳定性获得了显著提升,即在150℃的发光强度比(相对于20℃)从15%提升至31%.本研究为发现具有良好热稳定性的新型Ce^(3+)掺杂红色荧光粉提供了有效的设计原则.

摘要：Silicon(Si)is a promising anode material for next-generation Li-ion *** nanometer-sized Si could alleviate the pulverization caused by large volume changes during deep ***,compression between agglomerated Si particles causes Si cracking and electrode *** this,we engineered a mechanical cushioning space between Si particles via elastic hollow graphene shells(GSs)to flexibly buffer volume changes and maintain the stability of the electrode *** stress generated from the Si volume expansion during lithiation was mechanically buffered and gently released by compression of the hollow space of the *** this Si/GS composite electrode,GS also reduced the local agglomeration of Si particles and effectively improved the overall *** these advantages,the designed Si/GS electrode showed an enhanced cycling performance with more than 1200 mA h g^(-1) at 0.8 A g^(-1) and an excellent rate capability of 1025 mA h g^(-1) at 4 A g^(-1) after 200 cycles.

摘要：Three-dimensional(3D)printing has attracted increasing research interest as an emerging manufacturing technology for devel-oping sophisticated and exquisite architecture through hierarchical *** has also been employed in various advanced industrial *** development of intelligent biomedical engineering has raised the requirements for 3D printing,such as flexible manufacturing processes and technologies,biocompatible constituents,and alternative ***,state-of-the-art 3D printing mainly involves inorganics or polymers and generally focuses on traditional industrial fields,thus severely limiting applications demanding biocompatibility and *** this regard,peptide architectonics,which are self-assembled by programmed amino acid sequences that can be flexibly functionalized,have shown promising potential as bioinspired inks for 3D ***,the combination of 3D printing and peptide self-assembly poten-tially opens up an alternative avenue of 3D bioprinting for diverse advanced ***,a small but innovative nation,has significantly contributed to 3D bioprinting in terms of scientific studies,marketization,and peptide architectonics,including modulations and applications,and ranks as a leading area in the 3D bioprinting *** review summarizes the recent progress in 3D bioprinting in Israel,focusing on scientific studies on printable components,soft devices,and tissue *** paper further delves into the manufacture of industrial products,such as artificial meats and bioinspired supramolecular architectures,and the mechanisms,physicochemical properties,and applications of peptide ***,Israel contributes significantly to the field of 3D bioprinting and should thus be appropriately recognized.

摘要：To realize a sustainable hydrogen energy infrastructure,techniques to produce hydrogen gas without involving fossil fuels are *** has been proposed in last century that producing hydrogen gas by splitting water could be a sustainable way because of plenty of water in this planet.

摘要：矸石胶结充填开采是一种重要的充填开采方法,然而,酸性矿井水会严重影响矸石胶结充填体的强度。在本研究中,将矸石胶结充填体试件分别置于不同环境(空气、水、硫酸溶液、硫酸与荷载耦合)中,测试了不同龄期试件的抗压强度、电阻率及超声波波速,监测了加载过程中试件的声发射能量数值,同时结合扫描电镜和X衍射分析不同龄期充填体的微观结构。结果表明,1)空气中与水中养护的充填体抗压强度的增长趋势随龄期的增加而逐渐减缓。硫酸溶液中的充填体强度在前90天大于空气及水中养护的充填体强度。硫酸溶液与荷载耦合作用下充填体的强度随龄期的下降速率比单一硫酸溶液作用的较为缓慢;2)不同龄期矸石胶结充填体电阻率与超声波波速与强度有较好的对应关系。受侵蚀后矸石胶结充填体的破坏形式较为多样,且在加载不同阶段表现出不同的声发射能量特征,可以将声发射能量激增作为充填体的破坏前兆;3)侵蚀产物前期填充充填体内部孔隙,提高了其强度,后期会导致充填体膨胀开裂,强度降低。施加40%应力强度比的荷载会抵抗硫酸溶液的侵蚀。本文研究结果可以为充填体的耐侵蚀设计提供参考。

摘要：Magnesium alloys have shown prospective applications as a new biodegradable metal within bone. To garantee the longterm biocompatibility, a Mg-Zn-Ca alloy,composing of essential elements for human, was prepared and its feasibility for orthopedic applications was investigated. The in vitro and in vivo corrosion of Mg-Zn-Ca alloy as well as the biocompatibility were studied. The in vitro corrosion tests in five kinds of physiological solutions showed that the corrosion rates and corrosion morphologies of the alloy were strongly influenced by the solution used. The addition of serum in Hank’s and MEM significantly slowed down the corrosion rate and improved the corrosion uniformity of the alloy. The corrosion rate decreased with increasing serum *** alloy showed the slowest corrosion rate as well as homogeneous corrosion morphology in MEM＋10%FBS. Both the indirect and direct cell experiments indicated good cytocompatibility of the extruded Mg-Zn-Ca alloy. In vivo, we observed a gradual degradation process from the surface of extruded Mg-Zn-Ca alloy and only 40% in volume of implant was left after 4 weeks implantation in medullary cavities of mice. The micro-CT and histological analyses revealed its good biocompatibility with peri-implant new bone formation and increasing cortical bone thickness with increasing implantation period. This study showed that the extruded MgZn-Ca alloy provided sufficient biocompatibility for orthopedic application, though the in vivo corrosion rate should be further reduced for clinical use.