法国几何学习空间模型(Geometric Work Space),最早由巴黎狄德罗大学的Alain Kuzniak提出,用于研究几何学习过程,之后拓展到一般数学领域,形成其他模型,如MWS(Mathematical Working Space)模型.该模型由认识论和认知两个层面,以及图形(...法国几何学习空间模型(Geometric Work Space),最早由巴黎狄德罗大学的Alain Kuzniak提出,用于研究几何学习过程,之后拓展到一般数学领域,形成其他模型,如MWS(Mathematical Working Space)模型.该模型由认识论和认知两个层面,以及图形(符号)、工具、推论三种成因组成.通过三种成因的双向转化,以及两两成因形成的垂直平面连接起两个层面,由此描述几何/数学学习的复杂动态过程.本文通过文献梳理了GWS模型的产生与发展,总结了国外对该模型的应用与实践,最后分析了该模型中国化的应用思路.展开更多
Elucidating the genetic basis of natural variation in grain size and weight among rice varieties can help breeders develop high-yielding varieties.We identified a novel gene,GW3a(Grain Weight 3a)(LOC_Os03g27350),that ...Elucidating the genetic basis of natural variation in grain size and weight among rice varieties can help breeders develop high-yielding varieties.We identified a novel gene,GW3a(Grain Weight 3a)(LOC_Os03g27350),that affects rice grain size and weight.gw3a mutants showed higher total starch content and dry matter accumulation than the wild type(WT),Nipponbare,suggesting that GW3a negatively regulates grain size and weight.Moreover,our study found that GW3a interacted with OsATG8 by cleaving it,suggesting that GW3a may be involved in the assembly of autophagosomes and starch degradation in plants.The haplotype analysis of GW3a showed functional differences between indica and japonica rice.Taken together,we conclude that GW3a is expressed in the autophagosome pathway regulating starch metabolism in rice,affecting yield-related traits,such as grain size,grain weight and thousand grain weight(TGW).Our findings also shed new light on autophagy-mediated yield trait regulation,proposing a possible strategy for the genetic improvement of high-yield germplasm in rice.展开更多
文摘法国几何学习空间模型(Geometric Work Space),最早由巴黎狄德罗大学的Alain Kuzniak提出,用于研究几何学习过程,之后拓展到一般数学领域,形成其他模型,如MWS(Mathematical Working Space)模型.该模型由认识论和认知两个层面,以及图形(符号)、工具、推论三种成因组成.通过三种成因的双向转化,以及两两成因形成的垂直平面连接起两个层面,由此描述几何/数学学习的复杂动态过程.本文通过文献梳理了GWS模型的产生与发展,总结了国外对该模型的应用与实践,最后分析了该模型中国化的应用思路.
基金This research was supported by the National Natural Science Foundation of China(32160485)Jiangxi Double Thousand Plan(jxsq2023201057)Key R&D Plan of Jiangxi Province(20224BBF62001,20224BBF61030).
文摘Elucidating the genetic basis of natural variation in grain size and weight among rice varieties can help breeders develop high-yielding varieties.We identified a novel gene,GW3a(Grain Weight 3a)(LOC_Os03g27350),that affects rice grain size and weight.gw3a mutants showed higher total starch content and dry matter accumulation than the wild type(WT),Nipponbare,suggesting that GW3a negatively regulates grain size and weight.Moreover,our study found that GW3a interacted with OsATG8 by cleaving it,suggesting that GW3a may be involved in the assembly of autophagosomes and starch degradation in plants.The haplotype analysis of GW3a showed functional differences between indica and japonica rice.Taken together,we conclude that GW3a is expressed in the autophagosome pathway regulating starch metabolism in rice,affecting yield-related traits,such as grain size,grain weight and thousand grain weight(TGW).Our findings also shed new light on autophagy-mediated yield trait regulation,proposing a possible strategy for the genetic improvement of high-yield germplasm in rice.
文摘为了研究时效强化对稀土镁合金磨损机理和摩擦变形行为的影响,采用挤压工艺制备GW83(Mg-8Gd-3Y-0.5Zr,质量分数/%)稀土镁合金。利用电子万能试验机测试合金的室温力学性能,利用光学显微镜(optical microscope,OM)、扫描电子显微镜(scanning electron microscope,SEM)、透射电子显微镜(transmission electron microscope,TEM)观察分析合金的组织,利用球-盘式干滑动摩擦磨损试验机测试分析合金的耐磨性能。结果表明:经过T5峰时效处理后,析出了大量透镜状β′相,硬度和抗拉强度分别为124.1HV和420.31 MPa,相比在挤压态(O态)时有明显的增加。在实验载荷范围内,随着载荷的增加,合金的摩擦因数逐渐降低,磨损率逐渐增加。T5处理可显著降低GW83镁合金的磨损体积,提高耐磨性能。耐磨性能的提升与磨损机制及摩擦变形程度的改变有关。在5~10 N时,两种样品的主要磨损机制均为磨粒磨损、氧化磨损与黏着磨损。当载荷增加至20 N,O态样品的主要磨损机制转变为剥层磨损,而T5态样品直至80 N才出现轻微剥层磨损机制。T5处理显著减小了由摩擦引起的表层金属变形程度和变形层厚度,减少了摩擦裂纹的产生。
