摘要：Cobalt nanoparticles(NPs)catalysts are extensively used in heterogeneous catalytic reactions,and the addition of alkali metal promoters is a common method to modulate the catalytic performance because the catalyst's surface structures and morphologies are sensitive to the addition of ***,the underlying modulation trend remains ***,the adsorption of alkali metal promoters(Na and K)on the surfaces of face-centered-cubic(FCC)and hexagonal-closest packed(HCP)polymorphous cobalt was systematically investigated using density functional ***,the effect of alkali promoters on surface energies and nanoparticle morphologies was revealed on the basis of Wulff *** FCC-Co,the exposed area of the(111)facet in the nanoparticle increases with the adsorption coverage of alkali metal ***,the(311),(110),and(100)facets would disappear under the higher adsorption coverage of alkali *** HCPCo,the Wulff morphology is dominated by the(0001)and(1011)facets and is independent of the alkali metal adsorption *** work provides insights into morphology modulation by alkali metal promoters for the rational design and synthesis of cobalt-based nanomaterials with desired facets and morphologies.

摘要：A grand challenge facing society is climate change caused mainly by rising CO_(2) concentration in Earth’s *** plants are linchpins in global carbon cycling,with a unique capability of capturing CO_(2) via photosynthesis and translocating captured carbon to stems,roots,and soils for long-term ***,many researchers postulate that existing land plants cannot meet the ambitious requirement for CO_(2) removal to mitigate climate change in the future due to low photosynthetic efficiency,limited carbon allocation for long-term storage,and low suitability for the *** address these limitations,there is an urgent need for genetic improvement of existing plants or construction of novel plant systems through biosystems design(or biodesign).Here,we summarize validated biological parts(e.g.,protein-encoding genes and noncoding RNAs)for biological engineering of carbon dioxide removal(CDR)traits in terrestrial plants to accelerate land-based decarbonization in bioenergy plantations and agricultural settings and promote a vibrant ***,we first summarize the framework of plant-based CDR(e.g.,CO_(2) capture,translocation,storage,and conversion to value-added products).Then,we highlight some representative biological parts,with experimental evidence,in this ***,we discuss challenges and strategies for the identification and curation of biological parts for CDR engineering in plants.

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：粉末床熔融增材制造技术已应用于功能梯度材料的制造.文献中报道了一种材料成分沿垂直于粉末铺粉方向变化的新设计.基于此设计,本工作采用离散单元数值模拟研究了两种密度差异较大的金属粉末在铺粉过程中颗粒的偏析情况.结果发现,在铺粉过程中,较大密度粉末(重颗粒)一侧的铺粉量小于较小密度粉末(轻颗粒)的一侧的铺粉量.这种现象表明重颗粒从粉末密度大的一侧向粉末密度较小的一侧扩散.这种扩散受铺粉速度影响较大,铺粉速度越快,扩散越明显.但粉末层厚度对扩散影响不大.结果还表明,重颗粒与轻颗粒间的粒径差异影响扩散较大,减小重颗粒的粒径可能是控制颗粒偏析的一种方案.

摘要：Laser powder bed fusion(LPBF)makes it possible for biodegradable zinc(Zn)to be used to produce customized orthopedic *** this research,we investigate the impact of laser power and scanning speed on the development of surface quality,relative densification,and texture during LPBF of Zn *** laser power was able to decrease melt viscosity and surface tension,which improved the metallurgical bonding between adjacent *** and twisted tracks also became continuous and *** speed could controlmolten-pool temperature to restrain grain natural orientation,achieving various crystal orientations and a weakened ***,it further avoided the thermal expansion and contraction caused by excessive energy storage and accumulation in the matrix,thus reducing the generation of high-dislocation *** a result,by selecting a reasonable laser power and scanning speed,the LPBF parts exhibited a flat surface morphology and a high density over 99.5%.Their average hardness,mechanical strength,and elongation reached 50.2 HV,127.8 MPa,and 7.6%,***,the parts displayed a moderate degradation rate and excellent osteogenic *** these results provide a basis for selecting process parameters to optimize the comprehensive properties of LPBF-processed Zn parts for biodegradable applications.

摘要：The commercialization of proton exchange membrane fuel cells(PEMFCs)could provide a cleaner energy society in the near ***,the sluggish reaction kinetics and harsh conditions of the oxygen reduction reaction affect the durability and cost of *** previous reports on Pt-based electrocatalyst designs have focused more on improving their activity;however,with the commercialization of PEMFCs,durability has received increasing ***-depth insight into the structural evolution of Pt-based electrocatalysts throughout their lifecycle can contribute to further optimization of their activity and *** development of in situ electron microscopy and other in situ techniques has promoted the elucidation of the evolution *** mini review highlights recent advances in the structural evolution of Pt-based *** mechanisms are adequately discussed,and some methods to inhibit or exploit the structural evolution of the catalysts are also briefly reviewed.

摘要：Harvesting the promising high energy density of advanced electrode materials in lithium-ion batteries is critically dependent on a mechanistic understanding on how the materials function and degrade along with the battery ***,we tracked phase transformations during(de)lithiation of Sb_(2)Se_(3) single crystals using in situ high-resolution transmission electron microscopy(HRTEM)technique,and revealed electro-chemo-mechanical evolution at the reaction *** effect of this electro-chemo-mechanical coupling has a complicated interplay on the lithiation kinetics and causes various types of defects at the reaction front,including dislocation dipoles,antiphase boundaries,and *** return,the formed cracks and related defects build a path for fast diffusion of lithium ions and trigger a highly anisotropic lithiation at the twisted reaction front,giving rise to the formation of presumably "dead" Sb_(2)Se_(3) nanodomains in amorphous Li_(x)Sb_(2)Se_(3).The detailed mechanistic understanding may facilitate the rational design of high-capacity electrode materials for battery applications.

摘要：本文研究了一种新型低密度(~6.24 g cm^(-3))双相AlTiVCoNi高熵合金,其组织结构由有序L21高熵金属间化合物、无序体心立方结构和纳米L21相多层次结构构成.该合金在1200℃+24 h热处理下未发生相结构转变,在此条件下具有优异的高温相结构稳定性,其铸态和热处理态的压缩屈服强度相当,达到~1.6 GPa.另外,该合金在室温和600℃条件下表现出了优异的强塑性匹配和优异的比屈服强度,分别达到了约261和210 MPa g^(-1)cm^(3).该合金的超高强度主要源于有序L21相与体心立方相的半共格界面导致的一种强相结构稳定性和多层次结构的复合强化机制.该合金在800和1000℃压缩过程中出现了动态再结晶软化,使得其高温强度有所降低.这种“具有半共格界面L21+体心立方+纳米L21颗粒”的多层次结构设计为开发新型低密度耐高温高熵合金提供了一种新设计思路.

摘要：Negative thermal expansion(NTE),as an abnormal physical behavior,has been followed by scientists’attention over the past 30 years,due to its fascinating physical mechanisms and the prospect of high-precision thermal expansion control[1-5].Although some NTE materials(alloys[6],cyanides[7],fluorides[8-10],nitrides[11],oxides[12,13],MOFs[14-16],etc.)have been found,their number and variety are still very small,limiting their *** and designing new NTE materials is an important and challenging topic for the development of the field of *** have been continually reviewing and summarizing obtained results to look to the future of NTE[17-23].

摘要：Global demand for food and bioenergy production has increased rapidly,while the area of arable land has been declining for decades due to damage caused by erosion,pollution,sea level rise,urban development,soil salinization,and water scarcity driven by global climate *** order to overcome this conflict,there is an urgent need to adapt conventional agriculture to water-limited and hotter conditions with plant crop systems that display higher water-use efficiency(WUE).Crassulacean acid metabolism(CAM)species have substantially higher WUE than species performing C3 or C4 *** plants are derived from C3 photosynthesis ***,it is extremely unlikely that the C3 or C4 crop plants would evolve rapidly into CAM photosynthesis without human ***,there is growing interest in improving WUE through transferring CAM into C3 ***,engineering a major metabolic plant pathway,like CAM,is challenging and requires a comprehensive deep understanding of the enzymatic reactions and regulatory networks in both C3 and CAM photosynthesis,as well as overcoming physiometabolic limitations such as diurnal stomatal *** advances in CAM evolutionary genomics research,genome editing,and synthetic biology have increased the likelihood of successful acceleration of C3-to-CAM ***,we first summarize the systems biology-level understanding of the molecular processes in the CAM ***,we review the principles of CAM engineering in an evolutionary ***,we discuss the technical approaches to accelerate the C3-to-CAM transition in plants using synthetic biology toolboxes.