光电振荡器是一种能够稳定产生自激振荡的微波光子共振系统,近年来得到了广泛的研究,工作频率达到数百GHz,相位噪声性能达到-163 dBc/Hz at 6 kHz,调谐范围达到数十千兆赫兹。文章回顾了光电振荡器问世以来的部分研究进展和重要应用,重...光电振荡器是一种能够稳定产生自激振荡的微波光子共振系统,近年来得到了广泛的研究,工作频率达到数百GHz,相位噪声性能达到-163 dBc/Hz at 6 kHz,调谐范围达到数十千兆赫兹。文章回顾了光电振荡器问世以来的部分研究进展和重要应用,重点介绍了近年来集成化光电振荡器的研究现状,并提出了一种可应用于集成化光电振荡器的新型电光晶体材料。展开更多
Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are ess...Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are essential.Here,we report the synthesis of single crystals of the Kitaev quantum spin liquid candidate RuBr_(3),achieving millimeter-sized crystals through a self-flux method under high pressure and high temperature conditions.The crystals exhibit well-defined cleavage planes with a lustrous appearance.Transport characterizations exhibit a narrow band-gap semiconducting behavior with 0.13 eV and 0.11 eV band-gap in ab plane and along𝑐axis,respectively.Magnetic measurement shows a transition to antiferromagnetic(AFM)state at approximately 29K both in ab plane and along the c axis.Notably,the N′eel temperature increases to 34K with an applied magnetic field of up to 7T in the ab plane,but without any change along𝑐axis.The large size and high quality of RuBr3 single crystals provide a valuable platform for investigating various interactions,particularly the Kitaev interaction,and for elucidating the intrinsic physical properties of Kitaev quantum spin liquids.展开更多
A"verdict"on the economic value of the patent system by the US economist Fritz Machlup published in 1958 still has an important impact on assessing the effects of the patent system on economic development by...A"verdict"on the economic value of the patent system by the US economist Fritz Machlup published in 1958 still has an important impact on assessing the effects of the patent system on economic development by intellec-tual property scholars worldwide.This contribution analyses Machlup's study as is and in the light of subsequent US and global legal and economic developments.Machlup's assessment was examined based on empirical data generated by the US Bayh-Dole type legislation as regards the translation of basic research into innovative products and pro-cesses.Moreover,it analyses the impact of the new world economic order instituted in the framework of the World Trade Organization(WTO)mandatorily requiring effective patent protection in all WTO Member States on the eco-nomic development of developing and emerging economies.The case of China,which adopted its first Patent Law in 1984,is addressed in the context of Machlup's verdict and in light of the subsequent economic,scientific and techno-logical development of that country.Concluding thoughts consider today's value of Machlup's"verdict".展开更多
Plasma electrolytic oxidation(PEO)processing of light metals has been established for decades and is in increasing industrial use,even as an alternative surface treatment to produce multifunctional coatings with envir...Plasma electrolytic oxidation(PEO)processing of light metals has been established for decades and is in increasing industrial use,even as an alternative surface treatment to produce multifunctional coatings with environmental-friendly processing concept.One of the benefits of PEO processing claimed already a couple of years ago was the ability to treat dissimilar metal joints,which can obviously improve the surface homogeneity and stability at the interface of the dissimilar components,especially impeding the galvanic corrosion due to the different electrochemical properties of each component.However,the progress and breakthrough develop slowly especially for the macro scales due to the much larger gap between each component.This literature review firstly demonstrates the still low number of studies reporting successful PEO treatment of material combination such as Mg/Al,Mg/Ti,Al/Ti and scarcely light metal combinations with steel.The main issues and challenges to performing PEO processing on the macroscale dissimilar weldments were stated.On the other hand,dissimilar metal joints also widely exist in micrometer scale in alloys and metal matrix composites(MMCs).Moreover,there is a huge knowledge base on PEO treatment of such multiphase substrates.PEO processing of such complicated mixed microstructures is reviewed as well to reveal the basic problems.To some certain degree,these PEO-related studies on alloys and MMCs can be good examples to have an insight into the coating formation mechanism on macro-scaled dissimilar metal joints.Conclusions are drawn from the micro-to macroscale.Finally,critical access to the problems is given and possible solutions and reaming limitations are discussed.展开更多
Relationship between precipitation strengthening and creep resistance improvement has been an impor-tant topic for the widespread applications of magnesium alloys.Generally,static precipitation strength-ening through ...Relationship between precipitation strengthening and creep resistance improvement has been an impor-tant topic for the widespread applications of magnesium alloys.Generally,static precipitation strength-ening through thermal stable precipitates would generate satisfactory creep resistance.However,an op-posite example is presented in this work and we propose that the size of precipitates plays a crucial role in controlling the operative creep mechanisms.In addition,the precipitate components along with their crystal structures in the crept Mg-4Al-3Sm-0.4Mn samples with/without pre-aging were thor-oughly studied using Cs aberration-corrected high-angle annular dark-field scanning transmission elec-tron microscopy(HAADF-STEM).Previous aging generates a large density of fine precipitates(<~5 nm)homogeneously distributing in Mg matrix and exhibiting satisfactory strengthening effect.However,the number density of precipitate strings consisting of several or even dozens of relatively coarse precipitates(~10 nm)was significantly decreased at the same time.As revealed in this work,the relatively coarse particles in Mg matrix are much more efficient than the fine precipitates in promoting dislocation climb.Therefore,the rate-controlling mechanisms are transferred from dislocation climb to dislocation slip after previous aging,thus leading to degradation of creep resistance.Moreover,there are mainly five types of precipitates/clusters,namelyβ"-(Al,Mg)3Sm,Al5Sm3,ordered Al-Sm cluster,ordered Al-Mn cluster and ordered/unordered AlMnSm clusters.The crystal structures of the former two precipitates were discussed and the formation mechanisms of the precipitates/clusters were revealed.展开更多
With the growing demand for weight reduction,the application of joint lightweight structural materials is increasing.Magnesium alloys feature low density,high specific strength and good formability,offering significan...With the growing demand for weight reduction,the application of joint lightweight structural materials is increasing.Magnesium alloys feature low density,high specific strength and good formability,offering significant advantages for fuel efficiency and load capacity.Combined with Ti,a dissimilar Ti/Mg composite material provides great flexibility combining the properties of each material.However,because of the great differences in chemical and electrochemical properties between Mg and Ti,it is imperative to address the galvanic corrosion problem of such dissimilar Ti/Mg components.This work presents an investigation of the PEO processing of sintered Ti/Mg0.6Ca couples,aiming to improve the corrosion resistance of such dissimilar alloy combinations using a phosphate-aluminate electrolyte.The results show that uniform and continuous coatings can be formed on the dissimilar Ti/Mg0.6Ca couple.The coating mainly contains MgO and MgAl_(2)O_(4)on the Mg0.6Ca side,and Al_(2)TiO_(5)is the dominant phase on the Ti side.The work also took advantage of synchrotron X-ray computed tomography(CT)scanning to achieve 3D reconstruction of the coating morphology,which can be a fast method to assess the porosity and compactness of the coating and further predict the coating corrosion resistance.The coating effectively improved the corrosion resistance of the dissimilar Ti/Mg0.6Ca couple.展开更多
In this paper,the formation process,morphology,and electrochemical performance of PEO coatings on AM50 magnesium alloy prepared in low concentration phosphate,aluminate,and phosphate-aluminate electrolytes were system...In this paper,the formation process,morphology,and electrochemical performance of PEO coatings on AM50 magnesium alloy prepared in low concentration phosphate,aluminate,and phosphate-aluminate electrolytes were systematically studied.The results show that the coatings prepared from the phosphate electrolytes have a higher thickness and better corrosion resistance properties compared to the other electrolytes.The coatings prepared from low concentration phosphate-aluminate mixed electrolytes have slightly thinner thickness,a similar coating structure and an order of magnitude lower value of electrochemical impedance compared with phosphate electrolyte coatings.The Coatings prepared from low concentration aluminate electrolytes have the lowest thickness and the worst corrosion resistance properties which gets close to corrosion behavior of the bare AM50 under the same test conditions.Considering application,coatings prepared from single low concentration phosphate electrolytes and low concentration phosphate-aluminate electrolytes have greater potential than single low concentration aluminate coatings.However,reducing the electrolyte concentrations of coating forming ions too much has negative influence on the coating growth rate.展开更多
The effects of starch phosphate monoester content(SPC),namely C-3(C3P)and C-6 phosphate monoesters(C6P),on the starch properties were investigated using four potato starches with varied SPC/C3P/C6P and two nonphosphor...The effects of starch phosphate monoester content(SPC),namely C-3(C3P)and C-6 phosphate monoesters(C6P),on the starch properties were investigated using four potato starches with varied SPC/C3P/C6P and two nonphosphorylated maize starches with a similar range of amylose content(AC)as controls.The starch property results showed that a higher SPC is associated with lower turbidity,storage and loss modulus after storage,and water solubility,but higher swelling power(SP)and pasting viscosities.These findings suggested that SPC inhibited molecular rearrangement during storage and starch leaching during heating,and enhanced swelling and viscosities due to increased hydration and water uptake caused by the repulsion effect of phosphate groups and a less ordered crystalline structure.Increased SPC also resulted in lower resistant starch(RS)content in a native granular state but higher RS after retrogradation.Pearson correlations further indicated that SPC/C3P/C6P were positively correlated with peak(r^(2)=0.925,0.873 and 0.930,respectively),trough(r^(2)=0.994,0.968 and 0.988,respectively),and final viscosities(r^(2)=0.981,0.968 and 0.971,respectively).Notably,SPC,mainly C3P,exhibited a significantly positive correlation with SP(r^(2)=0.859)and setback viscosity(r^(2)=0.867),whereas SPC,mainly C6P,showed a weak positive correlation with RS after retrogradation(r^(2)=0.746).However,SPC had no significant correlations with water solubility,turbidity and rheology properties,which were more correlated with AC.These findings are helpful for the food industry to select potato starches with desired properties based on their contents of SPC,C3P,or C6P.展开更多
文摘光电振荡器是一种能够稳定产生自激振荡的微波光子共振系统,近年来得到了广泛的研究,工作频率达到数百GHz,相位噪声性能达到-163 dBc/Hz at 6 kHz,调谐范围达到数十千兆赫兹。文章回顾了光电振荡器问世以来的部分研究进展和重要应用,重点介绍了近年来集成化光电振荡器的研究现状,并提出了一种可应用于集成化光电振荡器的新型电光晶体材料。
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFA1406000 and 2022YFA1403800)the National Natural Science Foundation of China(Grant Nos.12474002,22171283,22203031,12434005,12204515,and 12074175)support of the Young Elite Scientists Sponsorship Program by CAST(Grant No.2022QNRC001)。
文摘Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are essential.Here,we report the synthesis of single crystals of the Kitaev quantum spin liquid candidate RuBr_(3),achieving millimeter-sized crystals through a self-flux method under high pressure and high temperature conditions.The crystals exhibit well-defined cleavage planes with a lustrous appearance.Transport characterizations exhibit a narrow band-gap semiconducting behavior with 0.13 eV and 0.11 eV band-gap in ab plane and along𝑐axis,respectively.Magnetic measurement shows a transition to antiferromagnetic(AFM)state at approximately 29K both in ab plane and along the c axis.Notably,the N′eel temperature increases to 34K with an applied magnetic field of up to 7T in the ab plane,but without any change along𝑐axis.The large size and high quality of RuBr3 single crystals provide a valuable platform for investigating various interactions,particularly the Kitaev interaction,and for elucidating the intrinsic physical properties of Kitaev quantum spin liquids.
文摘A"verdict"on the economic value of the patent system by the US economist Fritz Machlup published in 1958 still has an important impact on assessing the effects of the patent system on economic development by intellec-tual property scholars worldwide.This contribution analyses Machlup's study as is and in the light of subsequent US and global legal and economic developments.Machlup's assessment was examined based on empirical data generated by the US Bayh-Dole type legislation as regards the translation of basic research into innovative products and pro-cesses.Moreover,it analyses the impact of the new world economic order instituted in the framework of the World Trade Organization(WTO)mandatorily requiring effective patent protection in all WTO Member States on the eco-nomic development of developing and emerging economies.The case of China,which adopted its first Patent Law in 1984,is addressed in the context of Machlup's verdict and in light of the subsequent economic,scientific and techno-logical development of that country.Concluding thoughts consider today's value of Machlup's"verdict".
基金the China Scholarship Council(No.201708510113)for fellowship and funding.
文摘Plasma electrolytic oxidation(PEO)processing of light metals has been established for decades and is in increasing industrial use,even as an alternative surface treatment to produce multifunctional coatings with environmental-friendly processing concept.One of the benefits of PEO processing claimed already a couple of years ago was the ability to treat dissimilar metal joints,which can obviously improve the surface homogeneity and stability at the interface of the dissimilar components,especially impeding the galvanic corrosion due to the different electrochemical properties of each component.However,the progress and breakthrough develop slowly especially for the macro scales due to the much larger gap between each component.This literature review firstly demonstrates the still low number of studies reporting successful PEO treatment of material combination such as Mg/Al,Mg/Ti,Al/Ti and scarcely light metal combinations with steel.The main issues and challenges to performing PEO processing on the macroscale dissimilar weldments were stated.On the other hand,dissimilar metal joints also widely exist in micrometer scale in alloys and metal matrix composites(MMCs).Moreover,there is a huge knowledge base on PEO treatment of such multiphase substrates.PEO processing of such complicated mixed microstructures is reviewed as well to reveal the basic problems.To some certain degree,these PEO-related studies on alloys and MMCs can be good examples to have an insight into the coating formation mechanism on macro-scaled dissimilar metal joints.Conclusions are drawn from the micro-to macroscale.Finally,critical access to the problems is given and possible solutions and reaming limitations are discussed.
基金funded by the National Natural Science Foundation of China (Nos. 02110023210043, 51971042, U2167213, 51901028)supported by Sinoma Institute of Materials Research (Guang ZHOU) Co., Ltd (SIMR)gratefully acknowledged for financial support for Shi-bo ZHOU (No. 202106050089)
基金Chinese Academy of Sciences Youth Innovation Promotion Association(No.2023234)Scientific and Technological Developing Scheme of Jilin Province(No.20220402012GH)+2 种基金National Natural Science Foundation of China(No.U21A20323)Capital Construction Fund within the Budget of Jilin Province(No.2023C044-2)Major science and technology projects of Jilin Province and Changchun City(No.20220301026GX),the Special high-tech。
文摘Relationship between precipitation strengthening and creep resistance improvement has been an impor-tant topic for the widespread applications of magnesium alloys.Generally,static precipitation strength-ening through thermal stable precipitates would generate satisfactory creep resistance.However,an op-posite example is presented in this work and we propose that the size of precipitates plays a crucial role in controlling the operative creep mechanisms.In addition,the precipitate components along with their crystal structures in the crept Mg-4Al-3Sm-0.4Mn samples with/without pre-aging were thor-oughly studied using Cs aberration-corrected high-angle annular dark-field scanning transmission elec-tron microscopy(HAADF-STEM).Previous aging generates a large density of fine precipitates(<~5 nm)homogeneously distributing in Mg matrix and exhibiting satisfactory strengthening effect.However,the number density of precipitate strings consisting of several or even dozens of relatively coarse precipitates(~10 nm)was significantly decreased at the same time.As revealed in this work,the relatively coarse particles in Mg matrix are much more efficient than the fine precipitates in promoting dislocation climb.Therefore,the rate-controlling mechanisms are transferred from dislocation climb to dislocation slip after previous aging,thus leading to degradation of creep resistance.Moreover,there are mainly five types of precipitates/clusters,namelyβ"-(Al,Mg)3Sm,Al5Sm3,ordered Al-Sm cluster,ordered Al-Mn cluster and ordered/unordered AlMnSm clusters.The crystal structures of the former two precipitates were discussed and the formation mechanisms of the precipitates/clusters were revealed.
基金We also thank DESY(Hamburg,Germany)for granting beamtime to the proposal I-20221296 and support of the PETRAⅢP05 end-station.
文摘With the growing demand for weight reduction,the application of joint lightweight structural materials is increasing.Magnesium alloys feature low density,high specific strength and good formability,offering significant advantages for fuel efficiency and load capacity.Combined with Ti,a dissimilar Ti/Mg composite material provides great flexibility combining the properties of each material.However,because of the great differences in chemical and electrochemical properties between Mg and Ti,it is imperative to address the galvanic corrosion problem of such dissimilar Ti/Mg components.This work presents an investigation of the PEO processing of sintered Ti/Mg0.6Ca couples,aiming to improve the corrosion resistance of such dissimilar alloy combinations using a phosphate-aluminate electrolyte.The results show that uniform and continuous coatings can be formed on the dissimilar Ti/Mg0.6Ca couple.The coating mainly contains MgO and MgAl_(2)O_(4)on the Mg0.6Ca side,and Al_(2)TiO_(5)is the dominant phase on the Ti side.The work also took advantage of synchrotron X-ray computed tomography(CT)scanning to achieve 3D reconstruction of the coating morphology,which can be a fast method to assess the porosity and compactness of the coating and further predict the coating corrosion resistance.The coating effectively improved the corrosion resistance of the dissimilar Ti/Mg0.6Ca couple.
基金China Scholarship Council for the award of fellowship and funding(No.202006370022).
文摘In this paper,the formation process,morphology,and electrochemical performance of PEO coatings on AM50 magnesium alloy prepared in low concentration phosphate,aluminate,and phosphate-aluminate electrolytes were systematically studied.The results show that the coatings prepared from the phosphate electrolytes have a higher thickness and better corrosion resistance properties compared to the other electrolytes.The coatings prepared from low concentration phosphate-aluminate mixed electrolytes have slightly thinner thickness,a similar coating structure and an order of magnitude lower value of electrochemical impedance compared with phosphate electrolyte coatings.The Coatings prepared from low concentration aluminate electrolytes have the lowest thickness and the worst corrosion resistance properties which gets close to corrosion behavior of the bare AM50 under the same test conditions.Considering application,coatings prepared from single low concentration phosphate electrolytes and low concentration phosphate-aluminate electrolytes have greater potential than single low concentration aluminate coatings.However,reducing the electrolyte concentrations of coating forming ions too much has negative influence on the coating growth rate.
基金the China Scholarship Council funding(CSC,202006150028)for her PhD study at the University of Copenhagen,Denmark.
文摘The effects of starch phosphate monoester content(SPC),namely C-3(C3P)and C-6 phosphate monoesters(C6P),on the starch properties were investigated using four potato starches with varied SPC/C3P/C6P and two nonphosphorylated maize starches with a similar range of amylose content(AC)as controls.The starch property results showed that a higher SPC is associated with lower turbidity,storage and loss modulus after storage,and water solubility,but higher swelling power(SP)and pasting viscosities.These findings suggested that SPC inhibited molecular rearrangement during storage and starch leaching during heating,and enhanced swelling and viscosities due to increased hydration and water uptake caused by the repulsion effect of phosphate groups and a less ordered crystalline structure.Increased SPC also resulted in lower resistant starch(RS)content in a native granular state but higher RS after retrogradation.Pearson correlations further indicated that SPC/C3P/C6P were positively correlated with peak(r^(2)=0.925,0.873 and 0.930,respectively),trough(r^(2)=0.994,0.968 and 0.988,respectively),and final viscosities(r^(2)=0.981,0.968 and 0.971,respectively).Notably,SPC,mainly C3P,exhibited a significantly positive correlation with SP(r^(2)=0.859)and setback viscosity(r^(2)=0.867),whereas SPC,mainly C6P,showed a weak positive correlation with RS after retrogradation(r^(2)=0.746).However,SPC had no significant correlations with water solubility,turbidity and rheology properties,which were more correlated with AC.These findings are helpful for the food industry to select potato starches with desired properties based on their contents of SPC,C3P,or C6P.
