While researchers have proposed many techniques to mitigate the contention on the shared cache and memory bandwidth, none of them has considered the memory bus contention due to split lock. Our study shows that the sp...While researchers have proposed many techniques to mitigate the contention on the shared cache and memory bandwidth, none of them has considered the memory bus contention due to split lock. Our study shows that the split lock may cause 9X longer data access latency without saturating the memory bandwidth. To minimize the impact of split lock, we propose Kronos, a runtime system composed of an online bus contention tolerance meter and a bus contention-aware job scheduler. The meter characterizes the tolerance of jobs to the “pressure” of bus contention and builds a tolerance model with the polynomial regression technique. The job scheduler allocates user jobs to the physical nodes in a contention aware manner. We design three scheduling policies that minimize the number of required nodes while ensuring the Service Level Agreement (SLA) of all the user jobs, minimize the number of jobs that suffer from SLA violation without enough nodes, and maximize the overall performance without considering the SLA violation, respectively. Adopting the three policies, Kronos reduces the number of the required nodes by 42.1% while ensuring the SLA of all the jobs, reduces the number of the jobs that suffer from SLA violation without enough nodes by 72.8%, and improves the overall performance by 35.2% without considering SLA.展开更多
In this paper,the effect of different concentrations of sucrose stress on color formation of the Staphylococcus xylosus was investigated.The results showed that the highest a*value and the best coloring effect similar...In this paper,the effect of different concentrations of sucrose stress on color formation of the Staphylococcus xylosus was investigated.The results showed that the highest a*value and the best coloring effect similar to those of nitrite were observed after the addition of 0.05 g/mL sucrose to stress the S.xylosus.UV-Vis and electron spin resonance spectra analysis showed that production of coloring product Mb-NO was significantly enhanced after 0.05 g/mL sucrose stress.The growth curve,reactive oxygen content,cell cycle,nitric oxide synthase(NOS)activity,zeta potential,cell size,and protein composition of S.xylosus were investigated to reveal the mechanism of sucrose stress to enhance the coloring effect of the strain.The result showed that sucrose inhibited the growth of S.xylosus,which changed the physiological state by activating the oxidative stress response.The stress altered the rate of intracellular metabolism of S.xylosus by delaying the cell cycle and increasing cell surface zeta potential and cell particle size.These changes altered the protein composition of the cells and significantly enhanced the activity of intracellular NOS,which could improve the chromogenic ability of S.xylosus.This study will provide theoretical support for sucrose stress on S.xylosus to enhance its coloring effect,and sucrose stress for S.xylosus might be a promising biological alternative to nitrite in meat products.展开更多
A new kind of AlCoCrFeNiTi high-entropy alloy(HEA)as a grain refiner was prepared by vacuum arc melting.In this work,the effects of HEA(1.0 wt.%,2.0 wt.%and 3.0 wt.%)on the microstructure and mechanical properties of ...A new kind of AlCoCrFeNiTi high-entropy alloy(HEA)as a grain refiner was prepared by vacuum arc melting.In this work,the effects of HEA(1.0 wt.%,2.0 wt.%and 3.0 wt.%)on the microstructure and mechanical properties of pure aluminum were studied.The microstructure was characterized and examined by scanning electron microscope(SEM),energy dispersive X-ray spectroscopy(EDS),X-ray diffraction(XRD),electron probe micro-analyzer(EPMA)and transmission electron microscopy(TEM)to indicate the refining abilities and mechanism of HEA on pure aluminum.Results show that the addition of HEA refined both the macrostructure and microstructure of pure aluminum.When 1.0 wt.%HEA was added,most coarse columnar grains were refined into equiaxed crystals,and as the amount of HEA increased to 2.0 wt.%and3.0 wt.%,aluminum grains were further refined,and the grain boundaries were nearly indistinguishable.Moreover,the morphology ofα-Al transformed from coarse columnar crystals to equiaxed grains,and the mean size ofα-Al grains decreased from 374μm to 27μm.The Al3Ti,Al3Ni,and nano-phase precipitated from the aluminum alloy with HEA in the solidification.The typical rod-like nano-phases distributed interdendritic regions ofα-Al.The average length of nano-phases is 2568 nm,4372 nm,and 6907 nm and the average diameter is 112 nm,103 nm,and 92 nm when 1.0 wt.%,2.0 wt.%and 3.0 wt.%HEA were added to the pure aluminum,respectively.The ultimate tensile strength(UTS)and yield strength(YS)were improved in all samples,whereas the elongation(El)was decreased with increasing HEA concentration.When 3.0 wt.%HEA was added into the aluminum melt,the UTS was improved by 145.2%from62 MPa to 152 MPa,the YS was increased by 173.8%from 42 MPa to 115 MPa,and the El was decreased by 33.3%from 39%to 26%.展开更多
Evaluation of the river ecological environment can provide a basis for river management and ecological restoration.To conduct a comprehensive health assessment of the rivers in Tianjin,their biological,physical,and ch...Evaluation of the river ecological environment can provide a basis for river management and ecological restoration.To conduct a comprehensive health assessment of the rivers in Tianjin,their biological,physical,and chemical indicators are investigated on the basis of 32 river monitoring sites from August to September 2018.The comprehensive pollution and ecological integrity indexes of the rivers are analyzed.Results of the two evaluations,compared to achieve the river ecological environment evaluation,are as follows.1)Index of Ecological Integrity evaluation shows that among the sampling points,18.8%are"healthy",28.1%are"sub-healthy",40.6%are"fair",6.3%are"poor",and 6.3%are"very poor".2)The comprehensive evaluation of the chemical properties of the 32 river ecosystems in Tianjin shows severe overall river pollution and low standard water function area.Of the total sampling sites,16(50%)are heavily contaminated and 10(31.3%)are moderately contaminated.Excessive chemical oxygen demand and ammonia nitrogen are the main causes of water pollution.3)The Index of Ecological Integrity(IEI)has high correspondence with environmental factors.Pearson correlation analysis results show that the IEI index is significantly correlated with permanganate index(R=-0.453;P=0.023<0.05).Analysis results using BEST show that ammonia nitrogen is the best environmental parameter to explain the changes in IEI(R_(ho)=0.154;P=0.02<0.05)and those using RELATE show significant correlation between the biotic index and the environmental parameter matrices(R_(ho)=0.154;P=0.034<0.05).展开更多
基金sponsored by the National R&D Program of China (2018YFB1004800), the National Natural Science Foundation of China (Grant Nos. 62022057, 61632017, 61832006) and Alibaba Group. Quan Chen and Minyi Guo are the corresponding authors. We thank Chao Qian for his collaborative effort during data collection. And we also thank anonymous reviewers provided helpful comments on earlier drafts of the manuscript.
文摘While researchers have proposed many techniques to mitigate the contention on the shared cache and memory bandwidth, none of them has considered the memory bus contention due to split lock. Our study shows that the split lock may cause 9X longer data access latency without saturating the memory bandwidth. To minimize the impact of split lock, we propose Kronos, a runtime system composed of an online bus contention tolerance meter and a bus contention-aware job scheduler. The meter characterizes the tolerance of jobs to the “pressure” of bus contention and builds a tolerance model with the polynomial regression technique. The job scheduler allocates user jobs to the physical nodes in a contention aware manner. We design three scheduling policies that minimize the number of required nodes while ensuring the Service Level Agreement (SLA) of all the user jobs, minimize the number of jobs that suffer from SLA violation without enough nodes, and maximize the overall performance without considering the SLA violation, respectively. Adopting the three policies, Kronos reduces the number of the required nodes by 42.1% while ensuring the SLA of all the jobs, reduces the number of the jobs that suffer from SLA violation without enough nodes by 72.8%, and improves the overall performance by 35.2% without considering SLA.
基金the National Natural Science Foundation of China(No.31501512)。
文摘In this paper,the effect of different concentrations of sucrose stress on color formation of the Staphylococcus xylosus was investigated.The results showed that the highest a*value and the best coloring effect similar to those of nitrite were observed after the addition of 0.05 g/mL sucrose to stress the S.xylosus.UV-Vis and electron spin resonance spectra analysis showed that production of coloring product Mb-NO was significantly enhanced after 0.05 g/mL sucrose stress.The growth curve,reactive oxygen content,cell cycle,nitric oxide synthase(NOS)activity,zeta potential,cell size,and protein composition of S.xylosus were investigated to reveal the mechanism of sucrose stress to enhance the coloring effect of the strain.The result showed that sucrose inhibited the growth of S.xylosus,which changed the physiological state by activating the oxidative stress response.The stress altered the rate of intracellular metabolism of S.xylosus by delaying the cell cycle and increasing cell surface zeta potential and cell particle size.These changes altered the protein composition of the cells and significantly enhanced the activity of intracellular NOS,which could improve the chromogenic ability of S.xylosus.This study will provide theoretical support for sucrose stress on S.xylosus to enhance its coloring effect,and sucrose stress for S.xylosus might be a promising biological alternative to nitrite in meat products.
基金National Natural Science Foundation of China (52071259, 51834009)National Key R&D Program of China (2017YFE0301402)+1 种基金Research Program of Science and Technology of Shaanxi Province (2020zdzx04-04-01, 2018ZDXM-GY-136, 20JY050)Sponsored by State Key Laboratory of Long-Life High Temperature Materials (DTCC28EE190226)。
基金financially supported by the National Natural Science Foundation of China(No.51561021)the State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology(No.SKLAB02019007)the National Innovation Training Program of College Students of China(No.DC2019165 DC2019161)。
文摘A new kind of AlCoCrFeNiTi high-entropy alloy(HEA)as a grain refiner was prepared by vacuum arc melting.In this work,the effects of HEA(1.0 wt.%,2.0 wt.%and 3.0 wt.%)on the microstructure and mechanical properties of pure aluminum were studied.The microstructure was characterized and examined by scanning electron microscope(SEM),energy dispersive X-ray spectroscopy(EDS),X-ray diffraction(XRD),electron probe micro-analyzer(EPMA)and transmission electron microscopy(TEM)to indicate the refining abilities and mechanism of HEA on pure aluminum.Results show that the addition of HEA refined both the macrostructure and microstructure of pure aluminum.When 1.0 wt.%HEA was added,most coarse columnar grains were refined into equiaxed crystals,and as the amount of HEA increased to 2.0 wt.%and3.0 wt.%,aluminum grains were further refined,and the grain boundaries were nearly indistinguishable.Moreover,the morphology ofα-Al transformed from coarse columnar crystals to equiaxed grains,and the mean size ofα-Al grains decreased from 374μm to 27μm.The Al3Ti,Al3Ni,and nano-phase precipitated from the aluminum alloy with HEA in the solidification.The typical rod-like nano-phases distributed interdendritic regions ofα-Al.The average length of nano-phases is 2568 nm,4372 nm,and 6907 nm and the average diameter is 112 nm,103 nm,and 92 nm when 1.0 wt.%,2.0 wt.%and 3.0 wt.%HEA were added to the pure aluminum,respectively.The ultimate tensile strength(UTS)and yield strength(YS)were improved in all samples,whereas the elongation(El)was decreased with increasing HEA concentration.When 3.0 wt.%HEA was added into the aluminum melt,the UTS was improved by 145.2%from62 MPa to 152 MPa,the YS was increased by 173.8%from 42 MPa to 115 MPa,and the El was decreased by 33.3%from 39%to 26%.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment of China(No.2018ZX07111002)the Major Science and Technology Program for Water Pollution Control and Treatment of China(No.2017ZX07107001).
文摘Evaluation of the river ecological environment can provide a basis for river management and ecological restoration.To conduct a comprehensive health assessment of the rivers in Tianjin,their biological,physical,and chemical indicators are investigated on the basis of 32 river monitoring sites from August to September 2018.The comprehensive pollution and ecological integrity indexes of the rivers are analyzed.Results of the two evaluations,compared to achieve the river ecological environment evaluation,are as follows.1)Index of Ecological Integrity evaluation shows that among the sampling points,18.8%are"healthy",28.1%are"sub-healthy",40.6%are"fair",6.3%are"poor",and 6.3%are"very poor".2)The comprehensive evaluation of the chemical properties of the 32 river ecosystems in Tianjin shows severe overall river pollution and low standard water function area.Of the total sampling sites,16(50%)are heavily contaminated and 10(31.3%)are moderately contaminated.Excessive chemical oxygen demand and ammonia nitrogen are the main causes of water pollution.3)The Index of Ecological Integrity(IEI)has high correspondence with environmental factors.Pearson correlation analysis results show that the IEI index is significantly correlated with permanganate index(R=-0.453;P=0.023<0.05).Analysis results using BEST show that ammonia nitrogen is the best environmental parameter to explain the changes in IEI(R_(ho)=0.154;P=0.02<0.05)and those using RELATE show significant correlation between the biotic index and the environmental parameter matrices(R_(ho)=0.154;P=0.034<0.05).
