α+β固溶处理对Ti65合金薄板的影响:硅化物析出、力学行为和新型{1011}孪晶系

为应对航空领域对轻质和优异高温性能钛合金部件的迫切需求,对经不同热处理的新型高温钛合金Ti65合金薄板的显微组织演变、硅化物析出和力学行为进行系统研究。结果表明:在固溶空冷后的合金中析出亚微米级硅化物(Ti,Zr)_(6)Si_(3),导致拉伸性能变差和剧烈波动。在950℃固溶炉冷后的合金中发现穿晶界(Ti,Zr)_(5)Si_(3)和近晶界(Ti,Zr)_(6)Si_(3)硅化物的共存。当固溶温度升高至1010℃时,(Ti,Zr)_(3)Si硅化物在位错附件出现。薄板固有尺寸效应与硅化物析出的协同效应导致拉伸性能的明显波动,塑性显著下降,甚至发生脆性断裂。硅化物析出受低温固溶处理的保温时间的影响较弱。此外,在990℃热轧获得的薄板中观察到新型{1011}孪晶,其轴角对为65°<8443>,仅存在于粗大的基面织构α晶粒中。

Whole-genome resequencing of Japanese whiting(Sillago japonica) provide insights into local adaptations

The genetic adaptations of various organisms to heterogeneous environments in the northwestern Pacific remain poorly understood.Heterogeneous genomic divergence among populations may reflect environmentalselection.Advancingour understanding of the mechanisms by which organisms adapt to different temperatures in response to climate change and predicting the adaptive potential and ecological consequences of anthropogenic global warming are critical.We sequenced the whole genomes of Japanese whiting(Sillago japonica)specimens collected from different latitudinal locations along the coastal waters of China and Japan to detect possible thermal adaptations.Using population genomics,a total of 5.48 million single nucleotide polymorphisms(SNPs)from five populations revealed a complete genetic break between the Chinese and Japanese groups,which was attributed to both geographic distance and local adaptation.The shared natural selection genes between two isolated populations(i.e.,Zhoushan and Ise Bay/Tokyo Bay)indicated possible parallel evolution at the genetic level induced by temperature.These genes also indicated that the process of temperature selection on isolated populations is repeatable.Moreover,we observed natural candidate genes related to membrane fluidity,possibly underlying adaptation to cold environmental stress.These findings advance our understanding of the genetic mechanisms underlying the rapid adaptations of fish species.Species distribution projection models suggested that the Chinese and Japanese groups may have different responses to future climate change,with the former expanding and the latter contracting.The findings of this study enhance our understanding of genetic differentiation and adaptation to changing environments.

Chiral Br?nsted acid-catalyzed asymmetric intermolecular[4+2]annulation of ynamides with para-quinone methides

Catalytic asymmetric transformations of ynamides have attracted considerable attention in recent years.However,most of them were limited to intramolecular reactions or required metal catalysts.Herein,a chiral Br?nsted acid-catalyzed asymmetric intermolecular[4+2]annulation of ynamides with para-quinone methides(p-QMs)is disclosed,which not only represents the first metal-free protocol for catalytic asymmetric nucleophilic addition of ynamides to electrophiles,but also constitutes the first enantioselective annulation between p-QMs and alkynes.This methodology leads to the practical synthesis of biologically important chiral 4-aryl-3,4-dihydrocoumarins and 4-aryl-coumarins.Preliminary control experiments indicate that the orthohydroxyphenyl substituted p-QMs could isomerize into ortho-quinone methides(o-QMs)in the presence of chiral catalyst,which further react with ynamides via enantioselective[4+2]annulation,to generate the chiral product.

Br■nsted acid-catalyzed asymmetric dearomatization of indolyl ynamides: Practical and enantioselective synthesis of polycyclic indolines

Catalytic asymmetric dearomatization of indoles and alkynes has received much attention in the past decade because this strategy offers an attractive and alternative way for the efficient synthesis of valuable chiral polycyclic indolines. However, these reactions have been mostly limited to transition-metal catalysts, and the related chiral Br■nsted acid catalysis has been scarcely reported. Herein, we disclose a chiral phosphoric acid-catalyzed asymmetric dearomatization of indolyl ynamides by direct activation of alkynes. This metal-free method enables the practical and atom-economical construction of an array of valuable chiral polycyclic indolines in moderate to good yields with high enantioselectivities.

Over-expressing root-specific β-amyrin synthase gene increases glycyrrhizic acid content in hairy roots of glycyrrhiza uralensis

Objsective: Glycyrrhizia uralensis, one of the most widely-used traditional Chinese medicines, is mainly cropped in China. However, many cultivars are less in glycyrrhizic acid than Chinese Pharmacopoeia requires. In this paper, we improved glycyrrhizic acid by regulating β-amyrin synthase gene(GuBAS).Methods: Tobacco root-specific promoter TobRB7 and Gu BAS c DNA were obtained and combined with linearized pCAMBIA1305.1 to construct root-specific plant expression vector which was later transformed into Agrobacterium rhizogenes ACCC10060 by electrotransformation. The cotyledons and hypocotyls of G.uralensis were infected by the recombinant A. rhizogenes ACCC10060 to induce hairy roots. The GA content was quantified by HPLC.Results: The PCR and sequencing results both showed that three transgenic hairy root lines were obtained. The copy number of Gu BAS in these transgenic hairy roots was intended by q RT-PCR to be 3, 7,and 4. GA was detected by HPLC, and the results showed that GA was present in the three transgenic hairy roots, while absent in wild hairy roots.Conclusion: Over-expressing Gu BAS root-specifically in hairy roots of G. uralensis enhanced GA accumulation.

浙江大学特种控制阀研究室（英文）

目的:目前大中型控制阀大多存在结构复杂、驱动能耗大、反应时间慢、振动噪声大、稳定性差和使用寿命短等缺点。基于此,浙江大学相关研究人员组建了特种控制阀研究室,致力于提升控制阀的整体性能和设计水平。研究点:本研究室的主要方向为:1.控制阀内部流动特性分析和新结构设计开发;2.流体目标流量、温度、压力和振动噪声等的智能控制研究;3.适应纳米流体、压缩氢气和高温高压过热蒸汽等新流体介质的智慧控制阀研究。展望:特种控制阀作为超超临界火电机组、核电、石化高压反应和百万吨级乙烯工程等国家重大重点工程的关键零部件之一,将会在内流动机理、新结构开发、新流体介质和智能控制等研究领域得到广泛关注和长足发展。

Copper-Catalyzed Carbocyclization of Silyl Enol Ether Tethered Ynamides for Efficient and Practical Synthesis of 2-Azabicyclo[3.2.o] Compounds

Summary of main observation and conclusion An efficient copper-catalyzed carbocyclization of silyl enol ether tethered ynamides has been developed,allowing rapid and practical construction of diverse 2-azabicyclo[3.2.0]compounds in generally good to excellent yields with broad substrate scope under mild reaction conditions.Importantly,this protocol not only constitutes a rare example of non-noble metal-catalyzed alkyne carbocyclization,but also represents a rare cyclization on the B-position ofπu-tethered ynamides.The possibility of asymmetric carbocyclization via kinetic resolution also emerges.