111 research outputs found

    Magnetic Borophenes from an Evolutionary Search

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    A computational methodology based on ab initio evolutionary algorithms and spin-polarized density functional theory was developed to predict two-dimensional magnetic materials. Its application to a model system borophene reveals an unexpected rich magnetism and polymorphism. A metastable borophene with nonzero thickness is an antiferromagnetic semiconductor from first-principles calculations, and can be further tuned into a half-metal by finite electron doping. In this borophene, the buckling and coupling among three atomic layers are not only responsible for magnetism, but also result in an out-of-plane negative Poisson\u27s ratio under uniaxial tension, making it the first elemental material possessing auxetic and magnetic properties simultaneously

    Early selection of \u3cem\u3ebZIP73\u3c/em\u3e facilitated adaptation of \u3cem\u3ejaponica\u3c/em\u3e rice to cold climates

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    Cold stress is a major factor limiting production and geographic distribution of rice (Oryza sativa). Although the growth range of japonica subspecies has expanded northward compared to modern wild rice (O. rufipogon), the molecular basis of the adaptation remains unclear. Here we report bZIP73, a bZIP transcription factor-coding gene with only one functional polymorphism (+511 G\u3eA) between the two subspecies japonica and indica, may have facilitated japonica adaptation to cold climates. We show the japonica version of bZIP73 (bZIP73Jap) interacts with bZIP71 and modulates ABA levels and ROS homeostasis. Evolutionary and population genetic analyses suggest bZIP73 has undergone balancing selection; the bZIP73Jap allele has firstly selected from standing variations in wild rice and likely facilitated cold climate adaptation during initial japonica domestication, while the indica allele bZIP73Ind was subsequently selected for reasons that remain unclear. Our findings reveal early selection of bZIP73Jap may have facilitated climate adaptation of primitive rice germplasms

    Study of Peeling of Single Crystal Silicon by Intense Pulsed Ion Beam

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    The surface peeling process induced by intense pulsed ion beam (IPIB) irradiation was studied. Single crystal silicon specimens were treated by IPIB with accelerating voltage of 350 kV current density of 130 A/cm2. It is observed that under smaller numbers of IPIB shots, the surface may undergo obvious melting and evaporation..

    The roles of SMYD4 in epigenetic regulation of cardiac development in zebrafish

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    SMYD4 belongs to a family of lysine methyltransferases. We analyzed the role of smyd4 in zebrafish development by generating a smyd4 mutant zebrafish line (smyd4L544Efs*1) using the CRISPR/Cas9 technology. The maternal and zygotic smyd4L544Efs*1 mutants demonstrated severe cardiac malformations, including defects in left-right patterning and looping and hypoplastic ventricles, suggesting that smyd4 was critical for heart development. Importantly, we identified two rare SMYD4 genetic variants in a 208-patient cohort with congenital heart defects. Both biochemical and functional analyses indicated that SMYD4(G345D) was pathogenic. Our data suggested that smyd4 functions as a histone methyltransferase and, by interacting with HDAC1, also serves as a potential modulator for histone acetylation. Transcriptome and bioinformatics analyses of smyd4L544Efs*1 and wild-type developing hearts suggested that smyd4 is a key epigenetic regulator involved in regulating endoplasmic reticulum-mediated protein processing and several important metabolic pathways in developing zebrafish hearts

    Study of Peeling of Single Crystal Silicon by Intense Pulsed Ion Beam

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    The surface peeling process induced by intense pulsed ion beam (IPIB) irradiation was studied. Single crystal silicon specimens were treated by IPIB with accelerating voltage of 350 kV current density of 130 A/cm2. It is observed that under smaller numbers of IPIB shots, the surface may undergo obvious melting and evaporation..

    Study on Ablation Products of Zinc by Intense Pulsed Ion Beam Irradiation

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    As a kind of flash heat source, intense pulse ion beam can be used for material surface modification. The ablation effect has important influence on interaction between IPIB and material. Therefore, the understanding of ablation mechanism is of great significance to IPIB application..

    Study of the intense pulsed electron beam energy spectrum from BIPPAB-450

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    Intense pulsed particle beams have been widely used and studied as an effective method for material surface modification in the past several decades. Beihang Intense Pulsed PArticle Beams 450 accelerator (BIPPAB-450) can produce Intense Pulsed Ion Beams (IPIB) and Electron Beams (IPEB) in two modes with different Magnetically Insulated Diodes (MID). For IPEB, the pulse duration, accelerating voltage, total beam current are 100ns, up to 450keV and 3kA, respectively..
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