摘要：The trend towards miniaturization has increased dramatically over the last decade, especially within the fields concerned with bioengineering, microelectronics, and aerospace. Micromillin8 is among the principal manu- facturing processes which have allowed the development of components possessing micrometric dimensions, being used to the manufacture of both forming tools and the final product. The aim of this work is to present the principal aspects related to this technology, with emphasis on the work material requirements, tool ma- terials and geometry, cutting forces and temperature, quality of the finished product, process modelling and monitoring and machine tool requirements. It can be noticed that size effect possesses a relevant role with regard to the selection of both work material （grain size） and tooling （edge radius）. Low forces and temper- ature are recorded during micromillin8, however, the specific cutting force may reach high values because of the ploughing effect observed as the uncut chip thickness is reduced. Finally, burr formation is the principal concern with regard to the quality of the finished part.

摘要：Kirigami, the ancient Japanese paper cutting technique, has been applied to achieve high stretchability and low energy loss of designed metallic glass. Despite the exploration of the underlying deformation mechanism of kirigami-inspired structures from the energy point of view, the morphable responses of the kirigami patterns and the origin of the kirigami response are yet to be fully understood. This study reveals the mechanical driven-forms of the kirigami structure with the corresponding deformation stages. Based on the beam deflection theory, the elastic buckling behavior of kirigami metallic glass is manifested and a critical force prediction model is developed. Moreover, a force concentration parameter is introduced in the rigid-plastic deformation stage, predicting the nominal ultimate force. The kirigami-inspired facture force is firstly proposed. The findings of these models are in good agreement with the experimental sizedependent kirigami responses, and expected to provide significant insights into the understanding of the deformation behavior and the design of kirigami metallic glasses.

摘要：Selective hydrodeoxygenation of lignin derivatives into aromatic compounds is a promising route for the upgrading of lignin *** carbide catalysts have exhibited excellent selectivity in hydrodeoxygenation reactions,while their structure-activity relationship is still in ***,a liquid-phase atomic layer deposition method was employed to synthesize W_(2)C/SiO_(2) catalysts with uniform and size-controllable W_(2)C *** gas-phase hydrodeoxygenation of lignin-derived m-cresol at 350℃,these W_(2)C/SiO_(2) catalysts showed superior toluene selectivities(>95%)regardless of the W_(2)C particle *** optimal W_(2)C particle size of~7 nm was obtained for achieving the highest W_(2)C-based hydrodeoxygenation *** contrast,the turnover rate per surface W site increased almost monotonously as the W_(2)C particle size increased within 0.7-15 nm,attributable to high-index planes appeared on the larger W_(2)C *** effects of m-cresol and H_(2),taken together with temperature-programmed desorption of probe molecules and theoretical treatments,further indicate that the W_(2)C surface is nearly saturated by adsorbed m-cresol or its derivates under the reaction condition and the H-addition of the C7H7*intermediate to form toluene,instead of the initial C-O cleavage in m-cresol,acts as the rate-determining step.A side-by-side comparison between W_(2)C(102)and W_(2)C(001)catalyst surfaces in theoretical simulations of m-cresol hydrodeoxygenation verifies that high-index planes can stabilize kinetically-relevant transition states more effectively than the low-index ones,as a result of more available less-coordinated active sites on the *** above findings bring new mechanistic insights into the site requirements of supported W_(2)C nanocatalysts,distinct from those metal-catalyzed hydrodeoxygenation of oxygenates.

摘要：Platinum(Pt)is an efficient catalyst for hydrogen evolution reaction(HER)and oxygen reduction reaction(ORR),but the debate of the relevance between the Pt particle size and its electrocatalytic activity still *** strong metal–support interaction(SMSI)between the metal and carrier causes the charge transfer and mass transport from the support to the ***,Pt species(0.5 wt.%)with various particle sizes supported on carbon nanotubes(CNTs)have been synthesized by a photo-reduction ***^1.5 nm-sized Pt catalyst shows much higher HER performance than the counterparts in all pH solutions,and the mass activity of it is even 23–36 times that of Pt/*** for ORR,the^3 nm-sized Pt catalyst exhibits the optimal performance,and the mass activity is 3 times and even 16 times that of Pt/C in acidic and alkaline media,*** high HER and ORR performances of the^1.5 nm-and^3 nm-sized Pt catalysts benefit from the SMSI between Pt and the CNTs matrix and the higher ratio of face sites to edge sites,which is meaningful for the design of efficient electrocatalysts for renewable energy application.

摘要：CO oxidation is probably the most studied reaction in heterogeneous *** reaction has become a hot topic with the discovery of nanogold catalysts,which are active at low temperatures（at or below room temperature）.Au catalysts are the benchmark for judging the activities of other metals in CO ***-group metals（PGMs） that give comparable performances are of particular *** this mini-review,we summarize the advances in various PGM（Pt,Pd,Ir,Rh,Ru）catalysts that have high catalytic activities in low-temperature CO oxidation arising from reducible supports or the presence of OH *** effects of the size of the metal species and the importance of the interface between the metal and the reducible support are covered and discussed in terms of their promotional role in CO oxidation at low temperatures.

摘要：Compared with the inherent brittleness of bulk silicon(Si)at ambient temperature,the nanosized Si materials with very high strength,plasticity,and anelasticity due to size effect,are all ***,the ultimate stretchability of Si nanostructure has not yet been demonstrated due to the difficulties in experimental ***,directly performing in-situ tensile tests in a scanning electron microscope after developing a protocol for sample transfer,shaping and straining,we report the customized nanosized Si mechanical metamaterial which overcomes brittle limitations and achieves an ultra-large tensile strain of up to 95%using the maskless focused ion beam(FIB)*** unprecedented characteristic is achieved synergistically through FIB-induced size-softening effect and engineering modification of mechanical metamaterials,revealed through analyses of finite element analysis,atomic-scale transmission electron microscope characterization and molecular dynamics *** work is not only instructive for tailoring the strength and deformation behavior of nanosized Si mechanical metamaterials or other bulk materials,but also of practical relevance to the application of Si nanomaterials in nanoelectromechanical system and nanoscale strain engineering.