The interaction of mineral oxides （α-A12O3, MgO, Fe2O3, and SiO2） with hydrogen peroxide was investigated using the Knudsen cell reactor. The initial reactive uptake coefficients for tile commercially available pow...The interaction of mineral oxides （α-A12O3, MgO, Fe2O3, and SiO2） with hydrogen peroxide was investigated using the Knudsen cell reactor. The initial reactive uptake coefficients for tile commercially available powders are measured as （1.00±0.11）×10-4 for α-A1203, （1.66±0.23）×10-4 for MgO, （9.70±1.95）×10-5 for Fe203, and （5.22±0.9）×10-5 for SiO2. These metal oxide powders exhibit some catalytic behavior toward the decomposition of hydrogen peroxide excluding SiO2. H2O2 can be destroyed on Fe2O3 surface and O2 is formed. The experimental results suggest that the heterogeneous loss on mineral surface can represent an important sink of hydrogen peroxide.展开更多
The insulin/insulin-like growth factor 1 (IGF-1) signaling pathway is evolutionary conserved in diverse speciesincluding C.elegans, saccharomyces cerevisiae, Drosophila melanogaster, rodents and humans, which is invol...The insulin/insulin-like growth factor 1 (IGF-1) signaling pathway is evolutionary conserved in diverse speciesincluding C.elegans, saccharomyces cerevisiae, Drosophila melanogaster, rodents and humans, which is involved in many interrelated functions that are necessary for metabolism, growth and reproduction. Interestingly, more and more research has revealed that insulin/IGF-1 signaling pathway plays a pivotal role in the regulation of longevity. Generally, disruption of the power of this pathway will extend longevity in species ranging from C.elegansto humans. The role of insulin/IGF-1 in longevit yis probably related to stress resistance. Although the underlying mechanisms of longevity are not fully understood, the Insulin/IGF-1 signaling pathway has attracted substantial attention and it will be a novel target to prevent or postpone age-related diseases and extend life span. In this review, we mainly focus on the similar constitution and role of insulin/IGF-1 signaling pathway in C.elegans, saccharomyces cerevisiae, rodents and humans.展开更多
There is a pressing need for improving the current whole life shooting method in order to reduce ammunition consumption in the firearms lifetime test. The influencing factors, the characterization parameters and the c...There is a pressing need for improving the current whole life shooting method in order to reduce ammunition consumption in the firearms lifetime test. The influencing factors, the characterization parameters and the correlation analysis result of lifetime were considered. Accelerating life test and measuring scheme for machinegun were designed systematically by applying such theoretical methods as accelerating test, uniform design and lifetime model. As result, it provides a more scientific and reasonable accelerating life test scheme and proposes methods on modeling lifetime, optimizing model and characterizing lifetime. The conclusion can be used in preparing accelerating life test scheme and lifetime model for machinegun.展开更多
Fluorescence correlation spectroscopy （FCS） is a widely used method for measuring molecular diffusion and chemical kinetics. However, when a mixture of fluorescent species is taken into account, the conven- tional F...Fluorescence correlation spectroscopy （FCS） is a widely used method for measuring molecular diffusion and chemical kinetics. However, when a mixture of fluorescent species is taken into account, the conven- tional FCS method has limitations in extracting autocorrelations for different species and cross correla- tions between different species. Recently developed fluorescence lifetime correlation spectroscopy （FLCS） based on time-tagged time-resolved （TITR） photon recording, which can record the global and micro arrival time for each individual photon, has been used to discriminate different species according to fluorescence lifetime. Here, based on two-dimensional lifetime decay maps constructed from TITR photon stream, we have developed a quantitative lifetime-deconvolution FCS model （LDFCS） to extract precise chemical rates for chemical conversions in multi-species systems. The key point of LDFCS model is separation of different species according to the global distribution of fluorescence lifetime and then deconvolution of autocorrelations and cross-correlations from the two-dimensional lifetime decay maps constructed bv the micro arrival times of photon pairs at each delay time.展开更多
In the field of aerospace, minimum and seal of equipments cause the increase in the thermal loading sharply. Due to the lack of driving force, the performance of conventional condenser deteriorates greatly under the s...In the field of aerospace, minimum and seal of equipments cause the increase in the thermal loading sharply. Due to the lack of driving force, the performance of conventional condenser deteriorates greatly under the small gravity environment, which leads to reduction in the service life of equipments. In this study, a passive condenser, developed on basis of the phase separation concept,is utilized to improve the performance of the condensation heat transfer under the small gravity environment. As a result of the limitation of experiments, the mechanisms of heat transfer enhancement of the phase separation condenser tube are revealed through numerical simulation based on the volume-of-fluid(VOF) method. The following conclusions could be obtained:(1) A novel phase distribution of ‘‘gas near the tube wall and liquid in the tube core'' is formed. The thin liquid film is indeed created after the flow pattern modulation by inserting mesh cylinder.(2)The condensation quantity for single bubble in the annular region increases about 16 times greater than that in the bare tube region in the case of Jl= 0.0574 m/s and Jg= 0.0229 m/s.(3) Gas volume fraction affects the parameters of liquid film thickness, bubble length and liquid bridge length. The increase in the gas volume fraction results in the decrease in the evaluation index from21.56 to 12.82. The evaluation index is defined as the ratio of the condensation quantities per unit tube length of the annular region and the bare tube region.展开更多
基金This work was supported by the Knowledge Innovation Program of the Chinese Academy of Sciences （No.KJCX2-YW-N24, No.KZCX2-YW-Q02-03）the National Basic Research Program of China of Ministry of Science and Technology of China （No.2011CB403401） and the National Natural＇ Science Foundation of China （No.40925016, No.40830101, No.21077109, and No.41005070）.
文摘The interaction of mineral oxides （α-A12O3, MgO, Fe2O3, and SiO2） with hydrogen peroxide was investigated using the Knudsen cell reactor. The initial reactive uptake coefficients for tile commercially available powders are measured as （1.00±0.11）×10-4 for α-A1203, （1.66±0.23）×10-4 for MgO, （9.70±1.95）×10-5 for Fe203, and （5.22±0.9）×10-5 for SiO2. These metal oxide powders exhibit some catalytic behavior toward the decomposition of hydrogen peroxide excluding SiO2. H2O2 can be destroyed on Fe2O3 surface and O2 is formed. The experimental results suggest that the heterogeneous loss on mineral surface can represent an important sink of hydrogen peroxide.
基金Supported by the Major State Basic Research Development Program of China (973 Program), No. G2000057010
文摘The insulin/insulin-like growth factor 1 (IGF-1) signaling pathway is evolutionary conserved in diverse speciesincluding C.elegans, saccharomyces cerevisiae, Drosophila melanogaster, rodents and humans, which is involved in many interrelated functions that are necessary for metabolism, growth and reproduction. Interestingly, more and more research has revealed that insulin/IGF-1 signaling pathway plays a pivotal role in the regulation of longevity. Generally, disruption of the power of this pathway will extend longevity in species ranging from C.elegansto humans. The role of insulin/IGF-1 in longevit yis probably related to stress resistance. Although the underlying mechanisms of longevity are not fully understood, the Insulin/IGF-1 signaling pathway has attracted substantial attention and it will be a novel target to prevent or postpone age-related diseases and extend life span. In this review, we mainly focus on the similar constitution and role of insulin/IGF-1 signaling pathway in C.elegans, saccharomyces cerevisiae, rodents and humans.
文摘There is a pressing need for improving the current whole life shooting method in order to reduce ammunition consumption in the firearms lifetime test. The influencing factors, the characterization parameters and the correlation analysis result of lifetime were considered. Accelerating life test and measuring scheme for machinegun were designed systematically by applying such theoretical methods as accelerating test, uniform design and lifetime model. As result, it provides a more scientific and reasonable accelerating life test scheme and proposes methods on modeling lifetime, optimizing model and characterizing lifetime. The conclusion can be used in preparing accelerating life test scheme and lifetime model for machinegun.
基金supported by ‘‘Strategic Priority Research Program” of Chinese Academy of Sciences (XDA09040300)Beijing Science and Technology Project (Z151100003915077)+1 种基金Beijing Nova Programme (Z151100000315081)Beijing Talents Fund (2015000021223ZK17)
文摘Fluorescence correlation spectroscopy （FCS） is a widely used method for measuring molecular diffusion and chemical kinetics. However, when a mixture of fluorescent species is taken into account, the conven- tional FCS method has limitations in extracting autocorrelations for different species and cross correla- tions between different species. Recently developed fluorescence lifetime correlation spectroscopy （FLCS） based on time-tagged time-resolved （TITR） photon recording, which can record the global and micro arrival time for each individual photon, has been used to discriminate different species according to fluorescence lifetime. Here, based on two-dimensional lifetime decay maps constructed from TITR photon stream, we have developed a quantitative lifetime-deconvolution FCS model （LDFCS） to extract precise chemical rates for chemical conversions in multi-species systems. The key point of LDFCS model is separation of different species according to the global distribution of fluorescence lifetime and then deconvolution of autocorrelations and cross-correlations from the two-dimensional lifetime decay maps constructed bv the micro arrival times of photon pairs at each delay time.
基金supported by the National Natural Science Foundation of China(51476054 and 51506026)the Program for New Century Excellent Talents in University(NCET-13-0792)
文摘In the field of aerospace, minimum and seal of equipments cause the increase in the thermal loading sharply. Due to the lack of driving force, the performance of conventional condenser deteriorates greatly under the small gravity environment, which leads to reduction in the service life of equipments. In this study, a passive condenser, developed on basis of the phase separation concept,is utilized to improve the performance of the condensation heat transfer under the small gravity environment. As a result of the limitation of experiments, the mechanisms of heat transfer enhancement of the phase separation condenser tube are revealed through numerical simulation based on the volume-of-fluid(VOF) method. The following conclusions could be obtained:(1) A novel phase distribution of ‘‘gas near the tube wall and liquid in the tube core'' is formed. The thin liquid film is indeed created after the flow pattern modulation by inserting mesh cylinder.(2)The condensation quantity for single bubble in the annular region increases about 16 times greater than that in the bare tube region in the case of Jl= 0.0574 m/s and Jg= 0.0229 m/s.(3) Gas volume fraction affects the parameters of liquid film thickness, bubble length and liquid bridge length. The increase in the gas volume fraction results in the decrease in the evaluation index from21.56 to 12.82. The evaluation index is defined as the ratio of the condensation quantities per unit tube length of the annular region and the bare tube region.
