Understandings of the effect of hot deformation parameters close to the practical production line on grain refinement are crucial for enhancing both the strength and toughness of future rail steels.In this work,the au...Understandings of the effect of hot deformation parameters close to the practical production line on grain refinement are crucial for enhancing both the strength and toughness of future rail steels.In this work,the austenite dynamic recrystallization(DRX)behaviors of a eutectoid pearlite rail steel were studied using a thermo-mechanical simulator with hot deformation parameters frequently employed in rail production lines.The single-pass hot deformation results reveal that the prior austenite grain sizes(PAGSs)for samples with different deformation reductions decrease initially with an increase in deformation temperature.However,once the deformation temperature is beyond a certain threshold,the PAGSs start to increase.It can be attributed to the rise in DRX volume fraction and the increase of DRX grain with deformation temperature,respectively.Three-pass hot deformation results show that the accumulated strain generated in the first and second deformation passes can increase the extent of DRX.In the case of complete DRX,PAGS is predominantly determined by the deformation temperature of the final pass.It suggests a strategic approach during industrial production where part of the deformation reduction in low temperature range can be shifted to the medium temperature range to release rolling mill loads.展开更多
Electron spins confined in semiconductor quantum dots(QDs)are one of potential candidates for physical implementation of scalable quantum information processing technologies.Tunnel coupling based inter exchange intera...Electron spins confined in semiconductor quantum dots(QDs)are one of potential candidates for physical implementation of scalable quantum information processing technologies.Tunnel coupling based inter exchange interaction between QDs is crucial in achieving single-qubit manipulation,two-qubit gate,quantum communication and quantum simulation.This review first provides a theoretical perspective that surveys a general framework,including the Helter−London approach,the Hund−Mulliken approach,and the Hubbard model,to describe the inter exchange interactions between semiconductor quantum dots.An electrical method to control the inter exchange interaction in a realistic device is proposed as well.Then the significant achievements of inter exchange interaction in manipulating single qubits,achieving two-qubit gates,performing quantum communication and quantum simulation are reviewed.The last part is a summary of this review.展开更多
Host-associated microbiota can significantly impact host fitness.Therefore,naturally occurring variations in microbiota may influence the health and persistence of their hosts.This finding is particularly important in...Host-associated microbiota can significantly impact host fitness.Therefore,naturally occurring variations in microbiota may influence the health and persistence of their hosts.This finding is particularly important in reintroduced animals,as they typically experience habitat changes during translocations.However,little is known about how microbiomes are altered in response to conservation translocation.Here,we accessed the gut microbiome of Przewalski’s horse(Equus przewalskii)populations in China from three nature reserves(i.e.Xinjiang Kalamaili Nature Reserve,KNR;Dunhuang Xihu National Nature Reserve,DXNNR;and Anxi Extreme-arid Desert Nature Reserve,AENR)using 16s rRNA gene and metagenome sequencing.The results showed that the microbial composition and function differed significantly across locations,while a subset of core taxa was consistently present in most of the samples.The abundance of genes encoding microbe-produced enzymes involved in the metabolism of carbohydrates,especially for glycoside hydrolases,was significantly higher in open-spaced KNR populations than in more confined AENR individuals.This study offers detailed and significant differential characters related to the microbial community and metabolic pathways in various reintroduced sites of Przewalski’s horse,which might provide a basis for future microecological and conservation research on endangered reintroduced animals.展开更多
Due to information asymmetry and strategic innovation,firms often encounter challenges related to insufficient driving forces and low-quality innovation outcomes.Analysts always act as information intermediaries who h...Due to information asymmetry and strategic innovation,firms often encounter challenges related to insufficient driving forces and low-quality innovation outcomes.Analysts always act as information intermediaries who help foster the advancement of corporate innovation activities and the conversion of innovation output.This study examines the impact of analyst coverage and forecasting bias on corporate innovation,employing data from China A-shared listed firms spanning the period 2007 to 2019.We measure corporate innovation from two perspectives:Input and output.Specifically,we use the ratio of research and development(R&D)expenditure to sales as a proxy for the innovation input and the number of patent citations excluding self-citations to measure innovation output.We find that analyst coverage promotes corporate innovation,which is consistent with the“bright”side of analyst coverage.However,the positive effect of analyst coverage hinges on effectively transmitting and disclosing accurate information to investors in the capital market.Based on this,analysts'forecasting bias includes forecasting dispersion and optimism bias.We find evidence that an increase in analysts'forecast dispersion leads to a decrease in corporate innovation quality.Moreover,this paper presents a novel approach by employing the regression discontinuity method to examine the effect of analyst optimistic bias on firm innovation.The empirical findings reveal that overly optimistic forecasts by analysts exacerbate innovation quality.These analyses enrich the research on analyst coverage and corporate innovation,providing an empirical basis for improving the capital market with the help of analysts.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52293395 and 52293393)the Xiongan Science and Technology Innovation Talent Project of MOST,China(No.2022XACX0500)。
文摘Understandings of the effect of hot deformation parameters close to the practical production line on grain refinement are crucial for enhancing both the strength and toughness of future rail steels.In this work,the austenite dynamic recrystallization(DRX)behaviors of a eutectoid pearlite rail steel were studied using a thermo-mechanical simulator with hot deformation parameters frequently employed in rail production lines.The single-pass hot deformation results reveal that the prior austenite grain sizes(PAGSs)for samples with different deformation reductions decrease initially with an increase in deformation temperature.However,once the deformation temperature is beyond a certain threshold,the PAGSs start to increase.It can be attributed to the rise in DRX volume fraction and the increase of DRX grain with deformation temperature,respectively.Three-pass hot deformation results show that the accumulated strain generated in the first and second deformation passes can increase the extent of DRX.In the case of complete DRX,PAGS is predominantly determined by the deformation temperature of the final pass.It suggests a strategic approach during industrial production where part of the deformation reduction in low temperature range can be shifted to the medium temperature range to release rolling mill loads.
基金funded by National Natural Science Foundation of China,(Grant Nos.11974030 and 92165208)。
文摘Electron spins confined in semiconductor quantum dots(QDs)are one of potential candidates for physical implementation of scalable quantum information processing technologies.Tunnel coupling based inter exchange interaction between QDs is crucial in achieving single-qubit manipulation,two-qubit gate,quantum communication and quantum simulation.This review first provides a theoretical perspective that surveys a general framework,including the Helter−London approach,the Hund−Mulliken approach,and the Hubbard model,to describe the inter exchange interactions between semiconductor quantum dots.An electrical method to control the inter exchange interaction in a realistic device is proposed as well.Then the significant achievements of inter exchange interaction in manipulating single qubits,achieving two-qubit gates,performing quantum communication and quantum simulation are reviewed.The last part is a summary of this review.
基金We are grateful to rangers and staff members at the Xinjiang Kalamaili Nature Reserve,the Anxi Extremearid Desert Nature Reserve,and the Dunhuang Xihu National Nature Reserve for their support in sample collection.We would like to thank Editage(www.editage.cn)for English language editing.This work was supported by the Beijing Forestry University Outstanding Young Talent Cultivation Project[grant number 2019JQ03018]the Postdoctoral Innovative Talents Support Program[grant number BX20190042]+1 种基金the China Postdoctoral Science Foundation[grant number 2020M670177]L.T.acknowledges support from China Scholarship Council for her study at the University of Oxford(No.201906510039).
文摘Host-associated microbiota can significantly impact host fitness.Therefore,naturally occurring variations in microbiota may influence the health and persistence of their hosts.This finding is particularly important in reintroduced animals,as they typically experience habitat changes during translocations.However,little is known about how microbiomes are altered in response to conservation translocation.Here,we accessed the gut microbiome of Przewalski’s horse(Equus przewalskii)populations in China from three nature reserves(i.e.Xinjiang Kalamaili Nature Reserve,KNR;Dunhuang Xihu National Nature Reserve,DXNNR;and Anxi Extreme-arid Desert Nature Reserve,AENR)using 16s rRNA gene and metagenome sequencing.The results showed that the microbial composition and function differed significantly across locations,while a subset of core taxa was consistently present in most of the samples.The abundance of genes encoding microbe-produced enzymes involved in the metabolism of carbohydrates,especially for glycoside hydrolases,was significantly higher in open-spaced KNR populations than in more confined AENR individuals.This study offers detailed and significant differential characters related to the microbial community and metabolic pathways in various reintroduced sites of Przewalski’s horse,which might provide a basis for future microecological and conservation research on endangered reintroduced animals.
文摘Due to information asymmetry and strategic innovation,firms often encounter challenges related to insufficient driving forces and low-quality innovation outcomes.Analysts always act as information intermediaries who help foster the advancement of corporate innovation activities and the conversion of innovation output.This study examines the impact of analyst coverage and forecasting bias on corporate innovation,employing data from China A-shared listed firms spanning the period 2007 to 2019.We measure corporate innovation from two perspectives:Input and output.Specifically,we use the ratio of research and development(R&D)expenditure to sales as a proxy for the innovation input and the number of patent citations excluding self-citations to measure innovation output.We find that analyst coverage promotes corporate innovation,which is consistent with the“bright”side of analyst coverage.However,the positive effect of analyst coverage hinges on effectively transmitting and disclosing accurate information to investors in the capital market.Based on this,analysts'forecasting bias includes forecasting dispersion and optimism bias.We find evidence that an increase in analysts'forecast dispersion leads to a decrease in corporate innovation quality.Moreover,this paper presents a novel approach by employing the regression discontinuity method to examine the effect of analyst optimistic bias on firm innovation.The empirical findings reveal that overly optimistic forecasts by analysts exacerbate innovation quality.These analyses enrich the research on analyst coverage and corporate innovation,providing an empirical basis for improving the capital market with the help of analysts.
