The research on asphalt performance mainly focused on the macro performance and micro mechanism.Mesoscopic analysis was introduced to study the effect of rubber powder movement on asphalt rubber properties.After the p...The research on asphalt performance mainly focused on the macro performance and micro mechanism.Mesoscopic analysis was introduced to study the effect of rubber powder movement on asphalt rubber properties.After the preparation parameters and the preparation process of asphalt rubber were determined,the modification mechanism and rheological properties were analyzed which revealed the compatible stability mechanism.Then,the analysis model of asphalt rubber was established to focus on simulating the effect of rubber powder and the spatial movement on its mechanical properties.The experimental results show that rubber powder can make the asphalt rubber bear more uniform stress distribution and enhance the ability to resist deformation.Meanwhile,the rotational motion and final distribution of rubber powder have an obvious impact on the mechanical properties of asphalt rubber.In the selected feature points,the average stress of rubber powder at 0°space angle is only 34.1%of that at90°space angle.When the rubber powders are all in parallel in the ideal state,it enhances the mechanical properties the most.This study supplements the“mesoscopic”scale between macro and micro research.The relationship between micro mechanism and macro properties of asphalt rubber will be established from the mesoscopic perspective.It is also an effort to realize the effective correlation from micro,mesoscopic to macro in asphalt.展开更多
The physical performance of recycled asphalt was used as the main evaluation index to study the optimal range of a self-made rejuvenator.Through the penetration,viscosity and gel permeation chromatography(GPC)tests,th...The physical performance of recycled asphalt was used as the main evaluation index to study the optimal range of a self-made rejuvenator.Through the penetration,viscosity and gel permeation chromatography(GPC)tests,the diffusion degree of the rejuvenator under different temperatures and time process was analyzed,and the diffusion efficiency of the rejuvenator was evaluated from the macro and micro perspective.The regeneration mechanism of the rejuvenator in the aged asphalt was also analyzed using the Fourier transform infrared spectroscopy(FTIR),scanning electron microscope(SEM)and chemical composition tests.The research results showed that the optimum rejuvenator content was about 3%.Higher temperature and longer time were beneficial to improving the permeability and diffusion of the rejuvenator.During the aging process,the light components were reduced,and more macromolecular asphaltenes were generated as well as a large number of carbonyl and sulfoxide.After diffusion and regeneration,the light components in the asphalt were supplemented,the wrinkles and gullies of the aged asphalt were almost improved to the surface state of the matrix asphalt.展开更多
Near-infrared spectra of pathogenic bacteria (salmonella and Listeria monocytogenes ) were determined, and the spectral data were analyzed by the projection discriminant analysis based on principal component analysis ...Near-infrared spectra of pathogenic bacteria (salmonella and Listeria monocytogenes ) were determined, and the spectral data were analyzed by the projection discriminant analysis based on principal component analysis (PCA). The expected results were obtained. The results showed that salmonella and L. monocytogenes could be distinguished from each other by the near-infrared spectroscopy of the whole cells, cell walls or cytoplasm.展开更多
食品中的亚硫酸盐主要用途是在食品生产加工过程中充当漂白剂、防腐剂、脱色剂、抗氧化剂和防止酶变及非酶褐变的添加剂。本实验建立了食品中亚硫酸盐的离子色谱检测方法。以Metrosep A Supp5-150为色谱柱,淋洗液为3.2mM Na2CO3+1.0mM N...食品中的亚硫酸盐主要用途是在食品生产加工过程中充当漂白剂、防腐剂、脱色剂、抗氧化剂和防止酶变及非酶褐变的添加剂。本实验建立了食品中亚硫酸盐的离子色谱检测方法。以Metrosep A Supp5-150为色谱柱,淋洗液为3.2mM Na2CO3+1.0mM NaHCO3,流速0.8mL/min,进样体积25μL,化学抑制电导检测,结果表明,亚硫酸盐的残留量在0～10mg/L的范围内线性关系良好,相关系数为0.9994,加标回收率为97.5～102.4%。亚硫酸盐不稳定,因此样品采用40mmol/LNaOH溶液提取,甲醛作稳定剂。展开更多
This paper is the first attempt to investigate the risk probability criterion in semi-Markov decision processes with loss rates. The goal is to find an optimal policy with the minimum risk probability that the total l...This paper is the first attempt to investigate the risk probability criterion in semi-Markov decision processes with loss rates. The goal is to find an optimal policy with the minimum risk probability that the total loss incurred during a first passage time to some target set exceeds a loss level. First, we establish the optimality equation via a successive approximation technique, and show that the value function is the unique solution to the optimality equation. Second, we give suitable conditions, under which we prove the existence of optimal policies and develop an algorithm for computing ?-optimal policies. Finally, we apply our main results to a business system.展开更多
The discovery of intrinsic 2D ferromagnets provides exciting possibilities for spintronics applications. A particularly attractive example is CrI3, whose monolayer is ferromagnetic while bilayer shows antiferromagneti...The discovery of intrinsic 2D ferromagnets provides exciting possibilities for spintronics applications. A particularly attractive example is CrI3, whose monolayer is ferromagnetic while bilayer shows antiferromagnetic coupling. Because of weak interlayer coupling, the magnetism of bilayer CrI3 can be easily modulated by external perturbations, such as gating or pressure. Here, we constructed a magnetic phase diagram of bilayer CrI3 under arbitrary biaxial strain(within ±4%) from compression to stretch,and found that compressive strain can effectively convert the antiferromagnetic coupling of bilayer CrI3 to ferromagnetic.Detailed analyses on electronic structure were then performed to unravel the underlying mechanism of the magnetic phase transition. It was shown that both band gap and orbital composition at conduction band minimum play important roles in determining magnetic ground states of strained bilayer CrI3. These results strengthen our understanding of the interlayer magnetism of 2D magnets and provide a feasible way to modulate the magnetism in 2D layered materials.展开更多
基金Funded by the Key Research and Development Projects in Shaanxi Province (2022SF-328)the Science and Technology Project of Henan Department of Transportation (2020J-2-3)the Science and Technology Project of Shaanxi Department of Transportation (Nos.19-10K and 19-28K)。
文摘The research on asphalt performance mainly focused on the macro performance and micro mechanism.Mesoscopic analysis was introduced to study the effect of rubber powder movement on asphalt rubber properties.After the preparation parameters and the preparation process of asphalt rubber were determined,the modification mechanism and rheological properties were analyzed which revealed the compatible stability mechanism.Then,the analysis model of asphalt rubber was established to focus on simulating the effect of rubber powder and the spatial movement on its mechanical properties.The experimental results show that rubber powder can make the asphalt rubber bear more uniform stress distribution and enhance the ability to resist deformation.Meanwhile,the rotational motion and final distribution of rubber powder have an obvious impact on the mechanical properties of asphalt rubber.In the selected feature points,the average stress of rubber powder at 0°space angle is only 34.1%of that at90°space angle.When the rubber powders are all in parallel in the ideal state,it enhances the mechanical properties the most.This study supplements the“mesoscopic”scale between macro and micro research.The relationship between micro mechanism and macro properties of asphalt rubber will be established from the mesoscopic perspective.It is also an effort to realize the effective correlation from micro,mesoscopic to macro in asphalt.
基金Funded by the Science and Technology Project of Henan Department of Transportation(No.2020J-2-3)Shaanxi Transportation Science and Technology Project(Nos.17-05K,19-10K,19-28K)。
文摘The physical performance of recycled asphalt was used as the main evaluation index to study the optimal range of a self-made rejuvenator.Through the penetration,viscosity and gel permeation chromatography(GPC)tests,the diffusion degree of the rejuvenator under different temperatures and time process was analyzed,and the diffusion efficiency of the rejuvenator was evaluated from the macro and micro perspective.The regeneration mechanism of the rejuvenator in the aged asphalt was also analyzed using the Fourier transform infrared spectroscopy(FTIR),scanning electron microscope(SEM)and chemical composition tests.The research results showed that the optimum rejuvenator content was about 3%.Higher temperature and longer time were beneficial to improving the permeability and diffusion of the rejuvenator.During the aging process,the light components were reduced,and more macromolecular asphaltenes were generated as well as a large number of carbonyl and sulfoxide.After diffusion and regeneration,the light components in the asphalt were supplemented,the wrinkles and gullies of the aged asphalt were almost improved to the surface state of the matrix asphalt.
文摘Near-infrared spectra of pathogenic bacteria (salmonella and Listeria monocytogenes ) were determined, and the spectral data were analyzed by the projection discriminant analysis based on principal component analysis (PCA). The expected results were obtained. The results showed that salmonella and L. monocytogenes could be distinguished from each other by the near-infrared spectroscopy of the whole cells, cell walls or cytoplasm.
文摘食品中的亚硫酸盐主要用途是在食品生产加工过程中充当漂白剂、防腐剂、脱色剂、抗氧化剂和防止酶变及非酶褐变的添加剂。本实验建立了食品中亚硫酸盐的离子色谱检测方法。以Metrosep A Supp5-150为色谱柱,淋洗液为3.2mM Na2CO3+1.0mM NaHCO3,流速0.8mL/min,进样体积25μL,化学抑制电导检测,结果表明,亚硫酸盐的残留量在0～10mg/L的范围内线性关系良好,相关系数为0.9994,加标回收率为97.5～102.4%。亚硫酸盐不稳定,因此样品采用40mmol/LNaOH溶液提取,甲醛作稳定剂。
基金supported by National Natural Science Foundation of China(Grant Nos.61374067 and 11471341)
文摘This paper is the first attempt to investigate the risk probability criterion in semi-Markov decision processes with loss rates. The goal is to find an optimal policy with the minimum risk probability that the total loss incurred during a first passage time to some target set exceeds a loss level. First, we establish the optimality equation via a successive approximation technique, and show that the value function is the unique solution to the optimality equation. Second, we give suitable conditions, under which we prove the existence of optimal policies and develop an algorithm for computing ?-optimal policies. Finally, we apply our main results to a business system.
基金supported by the National Key Research and Development Program of China (Grant No. 2017YFB0701600)the National Natural Science Foundation of China (Grant Nos. 11974197+4 种基金51920105002)Shenzhen Basic Research Projects (Grant No. JCYJ20170407155608882)Guangdong Innovative and Entrepreneurial Research Team Program(Grant No. 2017ZT07C341)the Bureau of Industry and Information Technology of Shenzhen for the 2017 Graphene Manufacturing Innovation Center Project (Grant No. 201901171523)the China Postdoctoral Science Foundation (Grant No. 2018M631458)。
文摘The discovery of intrinsic 2D ferromagnets provides exciting possibilities for spintronics applications. A particularly attractive example is CrI3, whose monolayer is ferromagnetic while bilayer shows antiferromagnetic coupling. Because of weak interlayer coupling, the magnetism of bilayer CrI3 can be easily modulated by external perturbations, such as gating or pressure. Here, we constructed a magnetic phase diagram of bilayer CrI3 under arbitrary biaxial strain(within ±4%) from compression to stretch,and found that compressive strain can effectively convert the antiferromagnetic coupling of bilayer CrI3 to ferromagnetic.Detailed analyses on electronic structure were then performed to unravel the underlying mechanism of the magnetic phase transition. It was shown that both band gap and orbital composition at conduction band minimum play important roles in determining magnetic ground states of strained bilayer CrI3. These results strengthen our understanding of the interlayer magnetism of 2D magnets and provide a feasible way to modulate the magnetism in 2D layered materials.
