摘要：In order to simultaneously measure the initiation toughness of pure mode Ⅰ and mode Ⅱ cracks in one specimen,a large-size double-cracked concave-convex plate(DCCP)specimen configuration was *** tests were implemented in the drop plate impact *** gauges were employed to measure impact loads and crack initiation *** corresponding numerical model was established by using the dynamic finite difference program AUTODYN,and the experimental-numerical method and ABAQUS code were utilized to obtain the initial fracture toughness of the *** experiments and numerical research,we concluded that the DCCP specimen is suitable for measuring the initial fracture toughness of pure mode Ⅰ and mode Ⅱ cracks at the same time;the dynamic initiation toughness increases with the increase of loading rate and the crack initiation time decreases with increasing loading rate;the initiation toughness of mode Ⅱ crack is 0.5 times that of mode Ⅰ crack when subjected to the same loading *** the pre-crack in the vicinity of the bottom of a sample,when its length increases from 20 to 100 mm,the dynamic initiation toughness of the pure mode Ⅰ crack gradually decreases,and the longer the lower crack length is,the easier the crack would initiate,but the dynamic initiation toughness of pure mode Ⅱ crack varies little.

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：Artificial photonic synapses have set off a new upsurge for mimicking a series of neural activities in recent *** particular,the investigation of learning and memory behaviors with pressure or emotion and corresponding mechanisms is currently the focus of more ***,a hippocampus-inspired device based on MoS_(2) for illumination time encoding is fabricated,in which the encryption technology is employed for data *** addition,the pressureinduced memory behaviors with full memory function(memory trace)over time such as encoding,storage and retrieval are demonstrated,resulting from the decreasing positive photocurrent of the MoS;*** proposed mechanism of the memory effect when exposed to the light is elucidated in ***,the effect of stress hormone on memory behavior is displayed via different illumination time periods and light *** results indicate the potential application of MoS_(2) devices in artificial neural network.

摘要：利用二氧化碳作为C1原料进行硅氢化转化,是可持续性催化合成的重要方法之一.该方法能够将二氧化碳转化为不同氧化水平的高值化学品,例如甲酸、甲醛、甲醇和甲烷等.此外,胺可在特定的催化体系中与二氧化碳和硅烷多组分反应,实现基于二氧化碳硅氢化的N—H键酰基化和烷基化等转化.近年来,二氧化碳硅氢化领域的相关研究取得了显著的进展.综述了近三年来应用于二氧化碳硅氢化的主要均相催化体系的研究进展,介绍和总结催化剂的设计和相关催化性能,包括贵金属催化、廉价过渡金属催化、稀土金属催化、主族金属催化和无金属催化等催化体系,并讨论和展望了目前二氧化碳硅氢化的研究现状和潜在挑战.

摘要：Conjugated organic polymer(COP)-based electrochromic devices(ECDs)exhibit promising applications in digital and color ***,fabricating COP-based ECDs integrated with excellent electrochromic performance,customized patterns,and flexibility remains *** this study,we report inkjet-printed,flexible,and patterned ECDs based on two-dimensional(2 D)polyaniline(PANI)sheets,which are evenly dispersed in formic acid(FA)enabling high-precision,stable inkjet *** pristine lamellar structure of PANI sheets,which combine nanoscale thickness and an appropriate doping ratio,and the additive-free ink composition endow the printed PANI electrodes and ECDs with high *** fabricated PANI electrode exhibits a high optical contrast(76%at a wavelength of 750 nm),a good coloration efficiency(CE)of 259.1 cm^(2) C^(-1),and a short coloration/bleaching time(1.8/2.4 s),simultaneously integrated with pseudocapacitance and mechanical ***,the 2 D lamellar PANI ink developed in this study can be printed into various designed patterns,particularly for electrochemically controlled,addressable electrochromic *** work highlights 2 D lamellar PANI as a promising electrochromic material for flexible and patterned ECDs.

摘要：理解析氧反应(OER)电催化剂活性位点的活性来源是开发高效电催化剂的关键。然而,由于催化剂结构-活性关系的复杂性,发展高效电催化剂仍然是一个至关重要的挑战。本文设计了不同Co-N-C催化剂构型,包括单原子、双原子和团簇,并通过第一性原理计算建立了析氧反应构效关系。结果表明,Co-N4由于金属中心的高配位数和与所有析氧反应中间体的适中吸附能,表现出最佳反应性,过电位为0.37V。双原子和团簇的活性来源于催化剂自身与反应中间体相结合的高度配位结构。此外,本文基于Co-N4构型讨论了影响OER活性的其他因素,其中弱金属-金属相互作用可以通过调节Co-O的反键能级优化含氧中间体的吸附降低反应过电位。随后,根据建立的结构-吸附-活性关系,对火山图进行外推,得到CoNi-type4体系OER的过电位为0.23V。本文研究揭示了Co-N-C催化剂OER活性的起源,建立了基于原子尺度的Co-N-C催化剂的构效关系,有助于理解M-N-C基催化剂的高性能,并促进高效OER催化剂的设计。

摘要：Zero thermal expansion(ZTE)alloys have unique aspects in the application of the engineering of precise dimensional ***,the harsh conditions to realize ZTE,i.e.,appropriate coupling among spin,lattice,and charge upon heating,have limited the ZTE alloys by very few numbers of *** this work,we report a route to achieving twodimensional(2D)ZTE behavior by regulating crystallographic texture and magneto-volume effects(MVEs)in volumetric positive thermal expansion *** is illustrated in a series of Mn_(x)Fe_(5-x)Si_(3)compounds by those earth-abundant *** a result,a 2D ZTE performance with a coefficient of thermal expansion α_(1)=0.45×10^(-7)K^(-1) over a broad temperature window of 10–310 K was observed in *** experimental results by synchrotron X-ray diffraction,neutron diffraction,microscopy,and magnetization measurements reveal that such a ZTE behavior is strongly coupled with fiber crystallographic texture and magnetic moment at the crystallographic 6g site that dominates MVEs in the a-b *** competition between ferromagnetic Fe_(4d)–Fe_(6g)(J_(FM))and antiferromagnetic Mn_(4d)–Mn_(6g)(J_(AFM))interactions makes the Mn_(1.5)Fe_(3.5)Si_(3) and Mn_(2)Fe_(3)Si_(3)compounds show mixed magnetism and negative thermal expansion(NTE).The integral approach presented here can be used to extend the scope of ZTE/NTE species in other magnetic or ferroelectric materials.

摘要：The limitation of areal energy density of rechargeable aqueous hybrid batteries(RAHBs)has been a significant longstanding problem that impedes the application of RAHBs in miniaturized energy *** thick electrodes with optimized geometrical properties is a promising strategy for achieving high areal energy density,but the sluggish ion/electron transfer and poor mechanical stability,as well as the increased electrode thickness,itself present well-known *** this work,a 3D printing technique is introduced to construct an ultra-thick lithium iron phosphate(LFP)/carboxylated carbon nanotube(CNT)/carboxyl terminated cellulose nanofiber(CNF)composite electrode with uncompromised reaction kinetics for high areal energy density Li–Zn *** uniformly dispersed CNTs and CNFs form continuous interconnected 3D networks that encapsulate LFP nanoparticles,guaranteeing fast electron transfer and efficient stress relief as the electrode thickness ***,multistage ion diffusion channels generated from the hierarchical porous structure assure accelerated ion *** a result,LFP/Zn hybrid pouch cells assembled with 3D printed electrodes deliver a well-retained reversible gravimetric capacity of about 143.5 mAh g^(-1) at 0.5 C as the electrode thickness increases from 0.52 to 1.56 mm,and establish a record-high areal energy density of 5.25 mWh cm^(-2) with an impressive utilization of active material up to 30 mg cm^(-2) for an ultra-thick(2.08 mm)electrode,which outperforms almost all reported zinc-based hybrid-ion and single-ion *** work opens up exciting prospects for developing high areal energy density energy storage devices using 3D printing.

摘要：Designing high entropy alloys(HEAs) with high strength and excellent ductility has attracted extensive scientific interest. In the present work, the CALPHAD(calculation of phase diagrams) method was applied to guide the design of an(FeCoNi)92Al2.5Ti5.5 HEA strengthened by precipitation hardening. The grain size as well as the size and volume fraction of the precipitates was tailored via a thermomechanical process to optimize the mechanical *** uniformly dispersed nano-precipitates are Ni3(Al,Ti)-type precipitates with an L12 ordered structure presenting a fully coherent interface with the face-centered cubic(FCC) *** yield strength of the alloy increases from 338.3 to1355.9 MPa and the ultimate tensile strength increases from 759.3 to 1488.1 MPa, while the elongation maintains a reasonable value of 8.1%. The striking enhancement of strength is mainly caused by the precipitate’s hardening mechanism,which is evaluated quantitatively by various analytical *** deformation-induced microbands and the coherent precipitates sheared by dislocations are the deformation and strengthening mechanisms contributing to the superior combination of ductility and strength in the present *** investigation demonstrates that the CALPHAD method is beneficial to the design and optimization of HEAs.

摘要：The martensitic transformation,mechanical,and magnetic properties of the Ni_(2)Mn_(1.5-x)Cu_(x)Ti_(0.5) (x=0.125,0.25,0.375,0.5) and Ni_(2-y)Co_(y)Mn_(1.5-x)Cu_(x)Ti_(0.5)[(x=0.125,y=0.125,0.25,0.375,0.5) and (x=0.125,0.25,0.375,y=0.625)]alloys were systematically studied by the first-principles *** the formation energy,the martensite is smaller than the austenite,the Ni–(Co)–Mn–Cu–Ti alloys studied in this work can undergo martensitic *** austenite and non-modulated (NM) martensite always present antiferromagnetic state in the Ni_(2)Mn_(1.5-x)Cu_(x)Ti_(0.5) and Ni_(2-y)Co_(y)Mn_(1.5-x)Cu_(x)Ti_(0.5) (y<0.625) *** y=0.625 in the Ni_(2-y)Co_(y)Mn_(1.5-x)Cu_(x)Ti_(0.5) series,the austenite presents ferromagnetic state while the NM martensite shows antiferromagnetic *** doping can decrease the thermal hysteresis and anisotropy of the Ni–(Co)–Mn–Ti *** Mn and decreasing Ti content can improve the shear resistance and normal stress resistance,but reduce the toughness in the Ni–Mn–Cu–Ti *** the ductility of the Co–Cu co-doping alloy is inferior to that of the Ni–Mn–Cu–Ti and Ni–Co–Mn–Ti *** electronic density of states was studied to reveal the essence of the mechanical and magnetic properties.