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Alloy solidification: Assessment and improvement of an easy-to-apply model

Journal of Materials Science & Technology 2022年第35期130卷 1-11页

作者： H.Liu Y.Liu S.L.Lu Y.Zhang H.Chen Y.Chen M.Qian School of Materials Science and Engineering Southwest Jiaotong UniversityChengdu 610031China Centre for Additive Manufacturing School of EngineeringRMIT UniversityMelbourneVIC 3000Australia School of Materials Science and Engineering Sichuan UniversityChengdu 610065China

It has been a central task of solidification research to predict solute microsegregation. Apart from the Lever rule and the Scheil-Gulliver equation, which concern two extreme cases, a long list of microsegregation models has been proposed. However, the use of these models often requires essential experimental input information, e.g., the secondary dendrite arm spacing(λ), cooling rate( ˙T) or actual solidification range(△T). This requirement disables these models for alloy solidification with no measured values for λ,˙T and △T. Furthermore, not all of these required experimental data are easily obtainable. It is therefore highly desirable to have an easy-to-apply predictive model that is independent of experimental input,akin to the Lever rule or Scheil-Gulliver model. Gong, Chen, and co-workers have recently proposed such a model, referred to as the Gong-Chen model, by averaging the solid fractions(f_(s)) of the Lever rule and Scheil-Gulliver model as the actual solid fraction. We provide a systematic assessment of this model versus established solidification microsegregation models and address a latent deficiency of the model, i.e.,it allows the Lever rule solid fraction fsto be greater than one(f_(s)> 1). It is shown that the Gong-Chen model can serve as a generic model for alloy solidification until fsreaches about 0.9, beyond which(f_(s)> 0.9) its applicability is dictated by both the equilibrium solute partition coefcient(k) and the solute diffusion coefcient in the solid(Ds), which has been tabulated in detail.

关键词： Solidification Microsegregation Solute Back diffusion Eutectic formation

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Carrier-assisted differential detection

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Light(Science & Applications) 2020年第1期9卷 1835-1843页

作者： William Shieh Chuanbowen Sun Honglin Ji Department of Electrical and Electronic Engineering The University of MelbourneParkville VIC3010Australia

To overcome power fading induced by chromatic dispersion in optical fiber communications,optical field recovery is a promising solution for direct detection short-reach applications,such as fast-evolving data center interconnects(DCIs).To date,various direct detection schemes capable of optical field recovery have been proposed,including Kramers−Kronig(KK)and signal−signal beat interference(SSBI)iterative cancellation(IC)receivers.However,they are all restricted to the single sideband(SSB)modulation format,thus conspicuously losing half of the electrical spectral efficiency(SE)compared with double sideband(DSB)modulation.Additionally,SSB suffers from the noise folding issue,requiring a precise optical filter that complicates the receiver design.As such,it is highly desirable to investigate the field recovery of DSB signals via direct detection.In this paper,for the first time,we propose a novel receiver scheme called carrier-assisted differential detection(CADD)to realize optical field recovery of complex-valued DSB signals via direct detection.First,CADD doubles the electrical SE compared with the KK and SSBI IC receivers by adopting DSB modulation without sacrificing receiver sensitivities.Furthermore,by using direct detection without needing a precise receiver optical filter,CADD can employ cost-effective uncooled lasers as opposed to expensive temperature-controlled lasers in coherent systems.Our proposed receiver architecture opens a new class of direct detection schemes that are suitable for photonic integration analogous to homodyne receivers in coherent detection.

关键词： receiver precise coherent

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Cohort-based long-term ozone exposure-associated mortality risks with adjusted metrics:A systematic review and meta-analysis

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The Innovation 2022年第3期3卷 43-55页

作者： Haitong Zhe Sun Pei Yu Changxin Lan Michelle WLWan Sebastian Hickman Jayaprakash Murulitharan Huizhong Shen Le Yuan Yuming Guo Alexander T.Archibald Centre for Atmospheric Science Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridge CB21EWUK Department of Earth Sciences University of CambridgeCambridge CB23EQUK School of Public Health and Preventive Medicine Monash UniversityMelbourneVIC 3004Australia Institute of Reproductive and Child Health Key Laboratory of Reproductive HealthNational Health Commission of the People’s Republic of ChinaBeijing 100191China Department of Epidemiology and Biostatistics School of Public HealthPeking UniversityBeijing 100191China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen 518055China National Centre for Atmospheric Science Cambridge CB21EWUK

Long-term ozone(O_(3))exposure may lead to non-communicable diseases and increase mortality risk.However,cohort-based studies are relatively rare,and inconsistent exposure metrics impair the credibility of epidemiological evidence synthetization.To provide more accurate meta-estimations,this study updates existing systematic reviews by including recent studies and summarizing the quantitative associations between O_(3) exposure and cause-specific mortality risks,based on unified exposure metrics.Cross-metric conversion factors were estimated linearly by decadal observations during 1990-2019.

关键词： mortality ozone diseases

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Softening of phonon spectra in metallic glasses

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npj Computational Materials 2016年第1期2卷 31-35页

作者： Reza Mahjoub Nicholas E Hamilton Kevin J Laws Michael Ferry School of Materials Science and Engineering The University of New South WalesSydneyNSWAustralia

The vibrational spectra of a series of MgZnCa amorphous alloys were computed using density functional theory and implementing the small displacement method.The atomic structures of the alloys were obtained by ab initio molecular dynamics simulations.The vibrational thermodynamic properties were calculated as a function of temperature and,in particular,the specific heat at low temperature was approximated by temperature cubed based on the Debye model.We computed the contribution of Mg vibrations to the specific heat and investigated the softening of Mg phonon spectra,where the maximum allowed vibrational frequency is lowered and highly collective diffusion processes are promoted.The statistical correlation between the reported critical casting thickness of the alloys and softening of Mg phonons was obtained.Similar calculations were performed for two distinctively different amorphous ZrTiCuAl alloys with large and small reported critical casting thickness,respectively.The findings were consistent with those of the MgZnCa alloys.

关键词： alloys softening casting

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Antagonism between ambient ozone increase and urbanization-oriented population migration on Chinese cardiopulmonary mortality

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The Innovation 2023年第6期4卷 48-58页

作者： Haitong Zhe Sun Junchao Zhao Xiang Liu Minghao Qiu Huizhong Shen Serge Guillas Chiara Giorio Zosia Staniaszek Pei Yu Michelle W.L.Wan Man Mei Chim Kim Robin van Daalen Yilin Li Zhenze Liu Mingtao Xia Shengxian Ke Haifan Zhao Haikun Wang Kebin He Huan Liu Yuming Guo Alexander T.Archibald lYusuf Hamied Department of Chemistry University of CambridgeCambridge CB21EWUK Department of Earth Sciences University of CambridgeCambridge CB23EQUK Department of Environmental Health and Engineering Johns Hopkins Bloomberg School of Public HealthBaltimoreMD 21205USA State Key Joint Laboratory of ESPC State Environmental Protection Key Laboratory of Sources and Control of Air Pollution ComplexSchool of EnvironmentTsinghua UniversityBejing 100084China School of Atmospheric Sciences Nanjing UniversityNanjing 210023China Department of Earth System Science Stanford UniversityStanfordCA 94305USA School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen 518p55China Department of Statistical Science University College LondonLondon WC1E 6BTUK The Alan Turing Institute London NW12DBUK School of Public Heath and Preventive Medicine Monash UniversityMelboumeVIC 3004Australia British Heart Foundation Cardiovascular Epidemiology Unit Department of Public Health and Primary CareUniversity of CambridgeCambridge CB18RNUK Heart and Lung research Institute University of CambridgeCambridge CB20BDUK Baroelona Supercomputing Center Department of Earth Sciences08034 BarcelonaSpain School of Environmental Science and Engineering Nanjing University of Information Science and TechnologyNanjing 210044China Department of Mathematics University of CaliformiaLos AngelesLos AngelesCA 90095USA State Key Laboratory of New Ceramics and Fine Processing KeyLaboratory of Advanced Materials of Ministry of EducationSchool of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Department of Engineering University of CambridgeCambridge CB21PZUK National Centre for Atmospheric Science Cambridge CB21EWUK

Everincreasing ambient ozone(O3)pollution in China has been exacerbating cardiopulmonary premature deaths.However,the urban-rural exposure inequity has seldom been explored.Here,we assess populationcale 03 exposure and mortality burdens between 1990 and 2019 based on integrated pollution tracking and epidemiological evidence.We find Chinese population have been suffering from climbing 03 exposure by 4.3±2.8 ppb per decade as a result of rapid urbanization and growing prosperity of socioeconomic activities.Rural residents are broadly exposed to 9.8±4.1 ppb higher ambient O3 than the adjacent urban citizens,and thus urbaniza-tion-oriented migration compromises the exposure-associated mortality on total population.Cardiopulmonary excess premature deaths attributable to longterm 03 exposure,373,500(95%uncertainty interval[U]:240,600-510,900)in 2019,is underestimated in previous studies due to ignorance of cardiovascular causes.Future 03 pollution policy should focus more on rural population who are facing an aggravating threat of mortality risks to ameliorate environmental health injustice.

关键词： ambient urban urbanization

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二维金属氧化物和硫化物的结构调控及其高性能光电催化应用

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Science Bulletin 2021年第12期66卷 1228-1252,M0004页

作者：王宜超任白玉欧建臻徐凯杨春晖李永祥张海娇 School of Engineering RMIT UniversityMelbourneVic 3000Australia Institute of Nanochemistry and Nanobiology Shanghai UniversityShanghai 200444China Key Laboratory of Advanced Technologies of Materials.Ministry of Education School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China School of Engineering Western Sydney University.PenrithNSW 2751Australia

二维金属氧化物和硫族化物具有优异的物理化学性质,在光催化和电催化应用方面具有很大的潜力,可用于析氢反应、二氧化碳还原和氮还原等许多重要的化学反应.然而,由于导电率低、活性位点少和激发电荷的快速复合,未经改性的二维金属氧化... 详细信息

二维金属氧化物和硫族化物具有优异的物理化学性质,在光催化和电催化应用方面具有很大的潜力,可用于析氢反应、二氧化碳还原和氮还原等许多重要的化学反应.然而,由于导电率低、活性位点少和激发电荷的快速复合,未经改性的二维金属氧化物和硫族化合物通常显示出相对较差的催化性能.因此,需要对二维金属氧化物和硫族化合物合理的结构设计和化学修饰,从而改善和提高其催化性能.基于此,本综述从插层、掺杂、构造缺陷和界面设计以及与其他功能材料的复合等方面综述了近年来二维过渡金属氧化物和硫族化合物的研究进展.同时,系统地讨论了二维金属氧化物和硫族化合物的形貌、物理化学、电子和光学性质与电催化及光催化性能之间的关系.最后,我们对该领域的前景和挑战以及未来可能的研究方向进行了展望,旨在激发更多的研究来实现基于二维过渡金属氧化物和硫族化合物催化剂在能量存储和转换领域的应用.

关键词：电催化金属氧化物析氢反应二氧化碳还原硫族化合物能量存储化学修饰光催化

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