The genetic variation of the backcross modified lines developed from the maize line 08-641 selected by different directions

In this study, two donaors CN962 and 8065 were used to improve the resistance to northern leaf blight of the recurrent parent inbred line 08-641 (R08). A total of 79 lines (BC2F4) were developed by a bidirectional selection based on the similarity and dissimilarity in the shape and color of seeds to R08.The genetic variation of these lines were analyzed by 44 pairs of SSR molecular markers, the result showed that a total of 272 alleles were detected in the improved lines and R08, 123 out of them were detected in the modified lines but discarded in R08. The modified line selected based on dissimialry in the shape and corlor of seeds to R08 have lower genetic similary between R08 than that between the lines selected based on similary in the shape and color of seeds and R08, and the genetic variation of these lines were wider. It concluded that when the backcross breeding were used to improve the maize inbred lines, multidirectional selection based on phenotypic value were contribute to create and keep genetic variation.

Ultrathin salt-free polymer-in-ceramic electrolyte for solid-state sodium batteries

The practical energy density of solid-state batteries remains limited,partly because of the lack of a general method to fabricate thin membranes for solid-state electrolytes with high ionic conductivity and low area-specific resistance(ASR).Herein,we use an ultrahigh concentration of a ceramic ion conductor(Na_(3)SbS_(4))to build an ionconduction“highway”,and a polymer(polyethylene oxide,2 wt%)as a flexible host to prepare a polymer-inceramic ion-conducting membrane of approximately 40μm.Without the use of any salt(e.g.,NaPF_(6)),the resulting membrane exhibits a threefold increase in electronic ASR and a twofold decrease in ionic ASR compared with a pure ceramic counterpart.The activation energy for sodium-ion transport is only 190 meV in the membrane,similar to that in pure ceramic,suggesting ion transport predominantly occurs through a percolated network of ion-conducting ceramic particles.The salt-free design also provides an opportunity to suppress dendritic metal electrodeposits,according to a recently refined chemomechanical model of metal deposition.Our work suggests that salt is not always necessary in composite solid-state electrolytes,which broadens the choice of polymers to allow the optimization of other desired attributes,such as mechanical strength,chemical/electrochemical stability,and cost.

Synthesis of amorphous Pd-based nanocatalysts for efficient alcoholysis of styrene oxide and electrochemical hydrogen evolution

Amorphous nanomaterials with long-range disordered structures could possess distinct properties and promising applications,especially in catalysis,as compared with their conventional crystalline counterparts.It is imperative to achieve the controlled preparation of amorphous noble metal-based nanomaterials for the exploration of their phase-dependent applications.Here,we report a facile wet-chemical reduction strategy to synthesize various amorphous multimetallic Pd-based nanomaterials,including PdRu,PdRh,and PdRuRh.The phase-dependent catalytic performances of distinct Pd-based nanomaterials towards diverse catalytic applications have been demonstrated.Specifically,the usage of PdRu nanocatalysts with amorphous and crystalline face-centered cubic(fcc)phases can efficiently switch the ring-opening route of styrene oxide to obtain different products with high selectivity through alcoholysis reaction and hydrogenation reaction,respectively.Moreover,when used as an electrocatalyst for hydrogen evolution reaction(HER),the synthesized amorphous PdRh nanocatalyst exhibits low overpotential and high turnover frequency values,outperforming its crystalline fcc counterpart and most of the reported Pd-based HER electrocatalysts.

Recent Progress on Monoelemental Nanomaterials with Unconventional Crystal Phases

As an important parameter of crystalline materials,the crystal phase describes the periodic atomic arrangement in their structures.For some monoelemental materials,e.g.,carbon and phosphorus,they can exist in more than one crystal phase.The different crystal phases of monoelemental materials result in different physicochemical properties and functions.Therefore,engineering the crystal phase of monoelemental materials gives an effective strategy to modulate their properties and functions.Conventionally,the crystal phase of monoelemental materials can be altered under some harsh conditions,e.g.,high temperature and high pressure.Recently,with the rapid development of nanotechnology,various monoelemental materials with unconventional crystal phases have been well developed on the nanoscale.For example,our group has successfully achieved the synthesis of Au nanomaterials with unconventional hexagonal close-packed(hcp)2H and 4H phases by wetchemical methods,which exhibit distinct optical properties as well as outstanding electrocatalytic performance when compared to those with a thermodynamically stable facecentered cubic(fcc)phase.In this Account,we give a comprehensive overview of the recent development of monoelemental nanomaterials with unconventional crystal phases and their crystal-phase-dependent properties and applications.We first introduce the typical strategies for the synthesis of monoelemental nanomaterials with unconventional crystal phases.By using a wet-chemical reduction method,template-assisted method,and thermal annealing method,monoelemental nanomaterials with unconventional crystal phases can be directly prepared.Besides,unconventional-phase monoelemental nanomaterials can also be obtained via the phase transformation from materials with conventional crystal phases under specific conditions.In addition,some other methods have also been reported for preparing monoelemental nanomaterials with unconventional crystal phases,such as controlled crystallization of amorphous structure,the chemical vapor transport(CVT)method,electrodeposition,galvanic replacement,sputter-deposition,and so on.Subsequently,we summarize the unique structural stability and magnetic,electronic,optical,and other properties of the obtained monoelemental nanomaterials with unconventional crystal phases.We also highlight their promising applications in catalysis and batteries.Finally,we present our personal perspectives on the challenges and future opportunities in this important research field.