High Mixing Entropy Enhanced Energy States in Metallic Glasses

Owing to the nonequilibrium nature,the energy state of metallic glasses(MGs)can vary a lot and has a critical influence on the physical properties.Exploring new methods to modulate the energy state of glasses and studying its relationship with properties have attracted great interests.Herein,we systematically investigate the energy state,mixing entropy and physical properties of Zr–Ti–Cu–Ni–Be multicomponent high entropy MGs by experiments and simulations.We find that the energy state increases along with the increase of mixing entropy.The yield strength and thermal stability of MGs are also enhanced by high mixing entropy.These results may open a new door on regulation of energy states and thus physical properties of MGs.

Reply to“Comment on‘High Mixing Entropy Enhanced Energy States in Metallic Glasses'”

We thank Dr.Ristic and Dr.Babic for their interests in our work and for reminding us about their works on metallic glasses.Metallic glasses are a family of materials with disordered atomic packing structure,which makes it quite challenging to design new advanced metallic glasses and makes it charming to understand the relative physical mechanisms.

矮牵牛花朵大小遗传规律及相关基因的表达分析

花朵大小是植物进化及物种形成过程中的关键因子,也是决定植物观赏价值的重要性状,研究其遗传规律与调控机制具有重要的科学意义和实用价值。以不同花朵大小的矮牵牛(Petunia hybrida)自交系和原生种为材料,配制大花×中花和大花×小花杂交组合,构建遗传群体,研究其花朵大小的遗传规律。结果表明,大花自交系W与腋花矮牵牛S26(中花)杂交F_(1)群体均为大花,F_(2)群体中大花与中花的分离比接近3:1,BC1回交群体中大花与中花的分离比接近1:1;大花自交系W与中花自交系S杂交F_(1)群体均为大花, F_(2)群体花朵大小出现分离,大花与中花的比例接近2:1;大花自交系W与膨大矮牵牛S6 (小花)杂交F_(1)群体均为中花, F_(2)群体则出现花径从大到小的连续分布。利用主基因+多基因混合模型分析,按照AIC值最小的标准选出W×S26组合的最优模型为1MG-AD, W×S的最优模型为2MG-EAD,由此判定W大花对S26中花由1对主显性基因控制,具加性-显性效应,W大花对S中花则由2对主基因控制,具等加性-显性效应。此外,根据前期大、小花转录组分析结果,选取9个可能调控花朵大小的基因,通过qPCR检测了它们在不同花朵大小的矮牵牛株系花瓣中的表达水平,结果发现细胞分裂素受体基因PhHK以及响应细胞分裂素信号的type-ARRs基因在大花中的表达水平普遍高于中花和小花,表明细胞分裂素信号途径可能是参与调控矮牵牛大花性状的关键因素。

Relating microstructure to magnetocaloric properties in RE_(36)Tb_(20)Co_(20)Al_(24)(RE=Gd,Dy or Ho)high-entropy metallic-glass microwires designed by binary eutectic clusters method

The new high-entropy metallic-glasses(HE-MGs)are designed by using Dy and Ho to replace Gd in Gd_(36)Tb_(20)Co_(20)Al_(24)alloy based on the binary eutectic clusters method.Compared with the equiatomic Gd 25 Tb 25 Co 25 Al 25 HE-MG,the non-equiatomic RE_(36)Tb_(20)Co_(20)Al_(24)(RE=Gd,Dy,or Ho)alloys show bet-ter glass-forming ability,which is attributed to the deep binary eutectic compositions used for alloy de-sign.All RE_(36)Tb_(20)Co_(20)Al_(24)alloys undergo second-order magnetic transition.An extreme peak value of magnetic entropy change is obtained as 10.3 J kg^(-1) K-1(5 T)for the Ho_(36)Tb_(20)Co_(20)Al_(24)alloy.In-situ high-energy synchrotron X-ray diffraction was conducted to observe the microstructural difference among non-equiatomic samples at cryogenic temperatures.The results indicate that Gd_(36)Tb_(20)Co_(20)Al_(24)alloy possesses a relatively large average value of the dispersion of local clusters at a low-temperature range.This,com-bined with the critical exponentβclose to 0.5 of Gd_(36)Tb_(20)Co_(20)Al_(24)alloy,leads to its widest working temperature span among non-equiatomic samples.This work successfully establishes the connection be-tween microstructure and magnetocaloric properties of HE-MGs,which is beneficial for understanding the physical mechanism of the magnetocaloric behaviors of HE-MGs.

通过不同退火路径获得相同的玻璃态

本文以金基金属玻璃为模型,使用高精度闪速差示扫描量热法研究了等温退火和连续降温退火对焓弛豫和回复过程的影响.发现即使玻璃的能量(焓)一样,两种退火路径获得的玻璃的状态也可能不同.对于短时间等温退火或快速连续降温退火得到的高能量玻璃,两种退火路径获得的玻璃状态明显不同:连续降温退火得到的玻璃的弛豫峰更窄,而等温退火得到的玻璃弛豫峰更宽.但是,对于长时间等温退火或慢速连续降温退火得到的低能量玻璃,两种退火路径获得的玻璃状态趋于相同,即弛豫峰完全重合.弛豫动力学结果表明,高能量玻璃处在β弛豫阶段,具有热历史依赖性.而低能量玻璃处在α弛豫阶段,玻璃状态与热历史无关,这主要是因为α弛豫具有较强的协同性,具有各态遍历特征,使结构均一化.这些发现对精准调控玻璃性质具有重要意义.

具有大磁热效应的低钴含量Gd-Co-Al金属玻璃

磁制冷是一种具有广泛应用前景的制冷技术.文献表明,Gd基金属玻璃具有优异的磁热效应和优异的制冷能力.此类金属玻璃的开发通常需要先确定非晶的形成,再评价非晶形成合金的磁热效应.受制于传统的试错法,这一研发过程费时费力.本文以Gd-Co-Al合金体系为对象,通过组合制备和高通量结构表征快速揭示非晶形成成分范围,从而大幅减少需要单独测量磁热效应的成分空间.以文献数据呈现的规律为指导,在非晶形成合金中进一步获得三个具有大磁热效应的新成分:Gd_(60)Co_(10)Al_(30),Gd_(65)Co_(10)Al_(25)和Gd_(70)Co_(5)Al_(25).这三个新合金的磁热效应表明,Gd-Co-Al合金体系中存在一个临界Co含量和Gd/Co比例.超过临界值后,制冷能力达到饱和.这些研究结果有助于开发具有更大制冷能力的磁性材料.

Influence of thermal history on the crystallization behavior of high-Bs Fe-based amorphous alloys

A crucial step in creating cutting-edge soft magnetic alloys is the nanocrystallization of Fe-based amorphous alloys.However,it is unclear how the thermal history affects the nanocrystallization.In this work,high-precision nanocalorimetry and in-situ hightemperature transmission electron microscopy are used to systematically examine how the pre-annealing relaxation process affects the nanocrystallization of Fe-based amorphous alloys.We discover that the glass with more thermal energy storage will crystallize into superb nanocrystalline structures with exceptionally advanced soft magnetism.The soft magnetic properties of Fe-B nanocrystalline alloys can be improved by increasing the relaxation temperature.This finding provides solid and clear evidence for the influences of thermal history on crystallization behavior for Fe-based amorphous alloys,which is helpful for designing advanced soft magnetic nanocrystalline alloys.

Development,verification and application of a versatile aerosol calibration system for online aerosol instruments

Traditional calibration methods mostly focus on the calibration of detection systems while the calibration from the sampling and pre-condition systems to the detection system is usually ignored.In this regard,a Primary Standard Aerosol Mass Concentration Calibration System(PAMAS)is developed for the whole-process calibration of time-resolved aerosol measurement instruments.PAMAS is composed of a particle generation chamber,an ultrasonic atomizer,a dilution system,and a syringe pump.It is designed to steadily generate standard aerosol particles of known concentrations(≤250μg/m^(3)),chemical compositions,and stable particle size distributions.Monodispersed aerosol can be generated in the size range of hundreds of nanometers to several micrometers with a narrow size distribution.The generated particles with different compositions generated by PAMAS have been well verified by the filter-based gravimetric method,yielding accuracy and R^(2) of more than 95%and 0.999 in a wide concentration range.The response time by changing the target concentration of reference particles is 1-2 min.PAMAS has been applied to various types of time-resolved aerosol measurement instruments,including particle mass concentration monitors(Beta Attenuation and Tapered Element Oscillating Microbalance),online Ion Chromatograph,and semi-continuous OCEC carbon aerosol analyzer.Very consistent results between PAMAS and calibrated instruments can be obtained if the instruments are functioning well.As for instruments with certain technical issues,PAMAS can serve as a good tool for performance evaluation and quality assurance of the instruments and the accuracy of the measurement data can be adjusted based on the calibration results.

Response of PM_(2.5)-bound elemental species to emission variations and associated health risk assessment during the COVID-19 pandemic in a coastal megacity

The coronavirus(COVID-19)pandemic is disrupting the world from many aspects.In this study,the impact of emission variations on PM_(2.5)-bound elemental species and health risks associated to inhalation exposure has been analyzed based on real-time measurements at a remote coastal site in Shanghai during the pandemic.Most trace elemental species decreased significantly and displayed almost no diel peaks during the lockdown.After the lockdown,they rebounded rapidly,of which V and Ni even exceeded the levels before the lockdown,suggesting the recovery of both inland and shipping activities.Five sources were identified based on receptor modeling.Coal combustion accounted for more than 70%of the measured elemental concentrations before and during the lockdown.Shipping emissions,fugitive/mineral dust,and waste incineration all showed elevated contributions after the lockdown.The total non-carcinogenic risk(HQ)for the target elements exceeded the risk threshold for both children and adults with chloride as the predominant species contributing to HQ.Whereas,the total carcinogenic risk(TR)for adults was above the acceptable level and much higher than that for children.Waste incineration was the largest contributor to HQ,while manufacture processing and coal combustion were the main sources of TR.Lockdown control measures were beneficial for lowering the carcinogenic risk while unexpectedly increased the non-carcinogenic risk.From the perspective of health effects,priorities of control measures should be given to waste incineration,manufacture processing,and coal combustion.A balanced way should be reached between both lowering the levels of air pollutants and their health risks.

Online single particle analysis of chemical composition and mixing state of crop straw burning particles： from laboratory study to field measurement

Fresh straw burning （SB） particles were generated in the laboratory by the combustion of rice straw and corn straw. The chemical composition and mixing state of the fresh SB particles were investigated by an Aerosol Time-of-Flight Mass Spectrometer （ATOFMS）. Based on the mass spectral patterns, the SB particles were clustered into four major types： Salt, Organic Carbon （OC）, Elemental Carbon （EC）, and internally mixed particles of EC and OC （EC-OC）. In addition, particles containing ash, polycyclic aromatic hydrocarbons, heavy metals or nicotine were also observed. Physical and chemical changes of the SB particles immediately after the emission were analyzed with highly time-resolved data. During the aging processes, the average particle size increased steadily. Freshly emitted organic compounds were gradu- ally oxidized to more oxygenated compounds in the OC- containing particles. Meanwhile, an important displace- ment reaction （2KCI＋ SO24- KzSO4 ＋ 2C1-） was observed. The marker ions for SB particles were optimized and applied to identify the SB particles in the ambient atmosphere. The fluctuation of the number fraction of ambient SB particles sorted by ATOFMS agrees well with that of water soluble K＋ measured by an online ion chromatography, demonstrating that the optimized marker ions could be good tracers for SB particles in field measurements.

Taking advantage of glass:capturing and retaining the helium gas on the moon

Helium-3(3He)is a noble gas that has critical applications in scientific research and promising application potential as clean fusion energy.It is thought that the lunar regolith contains large amounts of helium,but it is challenging to extract because most helium atoms are reserved in defects of crystals or as solid solutions.Here,we find large amounts of helium bubbles in the glassy surface layer of ilmenite particles that were brought back by the Chang’E-5 mission.The special disordered atomic packing structure of glasses should be the critical factor for capturing the noble helium gas.The reserves in bubbles do not require heating to high temperatures to be extracted.Mechanical methods at ambient temperatures can easily break the bubbles.Our results provide insights into the mechanism of helium gathering on the moon and offer guidance on future in situ extraction.

Abnormal relaxation kinetics in D-mannitol glass confined by nanoporous alumina

The relaxation kinetics and phase transformations of the confined D-mannitol(DM)in nanoporous alumina are studied in-situ using a high-precision nano-calorimeter.We find that the crystallization behavior can be suppressed when it is confined in nanopores smaller than 50 nm.The confined DM glass has a much smaller fragility(~76)than free DM glass(~125),confirming the enhanced glass-forming ability.It is intriguing that during isothermal annealing both the confined and free DM glasses relaxation kinetics experience two relaxation stages that have distinct activation energies.The relaxation activation energy of the confined glass is about 25%-29%smaller than the free glass,which is attributed to the reduced dimensionality.The abnormal kinetics observed in the confined DM glass open a new avenue for preparing stable glasses.

Fast degradation of azo dye by nanocrystallized Fe-based alloys

Exploring new alloys with high efficiency in degrading organic pollutants in aqueous solutions is of wide interests. Here, we report that the nanocrystallized Fe_(82.65)Si_4B_(12)Cu_(1.35) alloy exhibits higher efficiency in decolorizing azo dye solutions compared to its amorphous counterpart. The increased efficiency is attributed to the formation of numerous microbatteries between the α-Fe(Si)and Fe_2 B nanocrystalline phases, which exhibit different corrosion potentials. These results suggest that nanocrystallized Fe-based amorphous composites hold promising application potential in degrading azo dyes solutions.

Inheritance factor on the physical properties in metallic glasses

Material genetic engineering can significantly accelerate the development of new materials.As an important topic in material science and condensed matter physics,the development of metallic glasses(MGs)with specific properties has largely been the result of trial and error since their discovery in 1960.Yet,property design based on the physical parameters of constituent elements of MGs remains a huge challenge owing to the lack of an understanding of the property inheritance from constitute elements to the resultant alloys.In this work,we report the inherent relationships of the yield strengthσ_(y),Young’s modulus E,and shear Modulus G with the valence electron density.More importantly,we reveal that the electronic density of states(EDOSs)at the Fermi surface(E_(F))is an inheritance factor for the physical properties of MGs.The physical properties of MGs are inherited from the specific element with the largest coefficient of electronic specific heat(γ_(i)),which dominates the value of the EDOS at E_(F).This work not only contributes to the understanding of property inheritances but also guides the design of novel MGs with specific properties based on material genetic engineering.