InSe has emerged as a promising candidate for next-generation electronics due to its predicted ultrahigh electrical performance.However,the efficacy of the InSe transistor in meeting application requirements is hinder...InSe has emerged as a promising candidate for next-generation electronics due to its predicted ultrahigh electrical performance.However,the efficacy of the InSe transistor in meeting application requirements is hindered due to its sensitivity to interfaces.In this study,we have achieved notable enhancement in the electrical performance of InSe transistors through interface engineering.We engineered an InSe/h-BN heterostructure,effectively suppressing dielectric layer-induced scattering.Additionally,we successfully established excellent metal-semiconductor contacts using graphene ribbons as a buffer layer.Through a methodical approach to interface engineering,our graphene/InSe/h-BN transistor demonstrates impressive on-state current,field-effect mobility,and on/off ratio at room temperature,reaching values as high as 1.1 mA/μm,904 cm^(2)·V^(-1)·s^(-1),and>10~6,respectively.Theoretical computations corroborate that the graphene/InSe heterostructure shows significant interlayer charge transfer and weak interlayer interaction,contributing to the enhanced performance of InSe transistors.This research offers a comprehensive strategy to elevate the electrical performance of InSe transistors,paving the way for their utilization in future electronic applications.展开更多
This paper presents an investigation on the effect of JPEG compression on the similarity between the target image and the background,where the similarity is further used to determine the degree of clutter in the image...This paper presents an investigation on the effect of JPEG compression on the similarity between the target image and the background,where the similarity is further used to determine the degree of clutter in the image.Four new clutter metrics based on image quality assessment are introduced,among which the Haar wavelet-based perceptual similarity index,known as HaarPSI,provides the best target acquisition prediction results.It is shown that the similarity between the target and the background at the boundary between visually lossless and visually lossy compression does not change significantly compared to the case when an uncompressed image is used.In future work,through subjective tests,it is necessary to check whether this presence of compression at the threshold of just noticeable differences will affect the human target acquisition performance.Similarity values are compared with the results of subjective tests of the well-known target Search_2 database,where the degree of agreement between objective and subjective scores,measured through linear correlation,reached a value of 90%.展开更多
Color coding is often used to enhance decision quality in complex man-machine interfaces of integrated display systems. However, people are easily distracted by irrelevant colors and by the numerous data points and co...Color coding is often used to enhance decision quality in complex man-machine interfaces of integrated display systems. However, people are easily distracted by irrelevant colors and by the numerous data points and complex structures in the interface. Although an increasing number of studies are seriously focusing on the problem of achieving efficient color coding, few are able to determine the effects of target and distractor saturations on cognitive performance. To study the performances of target colors among distractors, a systematic experiment is conducted to assess the influence of high and low saturated targets on cognitive performance, and the affecting extent of different saturated distractors of homogeneous colors on targets. According to the analysis of the reaction time through the non-parametric statistical method, a calculation method of the cognitive performance of each color is proposed. Based on the calculation of the color differences and the accumulation of the reaction times, it is shown that with the different saturated distractors of homogeneous colors, the high saturated yellow targets perform better than the low saturated ones, and the green and blue targets have moderate performances. When searching for a singleton target placed oll a black background, the color difference between the target and the distractor should be more than 20AE*ab units in the yellow saturation coding, whereas the color difference should be more than 40△E*ab units in the blue and green saturation coding. In addition, as regards saturation coding, the influence of the color difference between the target and the background on cognitive performance is greater than that of the color difference between the target and the distractor. Seemingly, the hue attribute determines whether the saturation difference between the target and the distractor affects thc cognitive performance. Based on the experimental results, the simulation design of the instrument dials in a flight situation awareness interface is completed and tested. Simulation results show the feasibility of the method of choosing the target and distractor colors, and the proposed research provides the instruction for the color saturation design of the interface.展开更多
This study investigates the impact of parental labor migration on the academic achievements and non-academic growth of left-behind children in fourth and seventh grades. Employing survey data collected from rural Chin...This study investigates the impact of parental labor migration on the academic achievements and non-academic growth of left-behind children in fourth and seventh grades. Employing survey data collected from rural China in 2014, 2015, and 2016, we examine the effect of parental absence on children's academic achievement using Propensity Score Matching(PSM) and Difference in Difference(DID) methods. The results demonstrate that left-behind children whose parents have migrated for one year have statistically significantly lower academic scores. Academic scores drop lower for fourthgrade students and students from higher-income families. There are also adverse effects on left-behind children's confidence, teacher-student relationships, subjective well-being, and educational expectations if parents migrate for one year. Surprisingly, if parental migration lasts longer(totaling two years), these adverse effects disappear, and student's educational expectations even improve. These results may be because, over time, the adverse effects that occur immediately after parental migration are offset by the positive effects of migration(i.e. higher income). These conclusions can inform migrant parents on ways to utilize their resources to improve the academic performance of their left-behind children.展开更多
Assessment of performance of China's sports industry is not only favorable for grasping development level of sports industry,but also able to,from micro perspective,find out factors influencing development of spor...Assessment of performance of China's sports industry is not only favorable for grasping development level of sports industry,but also able to,from micro perspective,find out factors influencing development of sports industry and their contribution to development of sports industry. Through selecting quantitative indicators for development of sports industry,the authors analyzed performance of development of sports industry in China and analyzed regional difference of sports industry by the data envelopment analysis( DEA) method. The study indicated that( i) performance of sports industry in recent years takes on growth trend,which may give the credit to scientific and technological progress;( ii) the development of sports industry in China has distinct spatial difference,best in eastern regions,better in middle regions,and poor in western regions.展开更多
Purpose: The aims of this study were to assess differences of limb symmetry index(LSI) in strength-and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related perform...Purpose: The aims of this study were to assess differences of limb symmetry index(LSI) in strength-and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related performance levels and to prospectively assess limb differences as a possible risk factor for traumatic and overuse injury in youth ski racers.Methods: The study(Study 1) included 285 high-level competitive ski racers(125 females, 160 males) of 3 age-related performance levels and based on the school system: 95 youth(10à14 years, secondary modern school), 107 adolescent(15à19 years, grammar school), and 83 elite athletes(20à34 years). To investigate the second aim(Study 2), 67 of the 95 youth athletes were included and any traumatic or overuse injuries were prospectively recorded over 2 seasons. All athletes performed 4 unilateral tests(strength related: one-leg counter movement jump(OL-CMJ) and one-leg isometric/isokinetic press strength test(OL-ILS); coordination related: one-leg stability test(OL-ST) and one-leg speedy jump test(OL-SJ)). The LSI was calculated by dividing the dominant leg by the nondominant leg and multiplying by 100. Kruskal-Wallis H tests and binary logistic regression analyses were conducted.Results: There were significant differences between the LSI of the 3 age-related performance-level groups only in the strength-related tests: the OL-CMJ(x2(2, 285) = 9.09; p = 0.01) and the OL-ILS(x2(2, 285) = 14.79; p < 0.01). The LSI for OL-ILS was found to be a significant risk factor for traumatic injury in youth ski racers(Wald = 7.08; p < 0.01). No significant risk factors were found for overuse injuries.Conclusion: Younger athletes display slightly greater LSI values only in the strength-related tests. The cut-off value of limb differences of <10%for return to sport decisions seems to be appropriate for elite athletes, but for youth and adolescent athletes it has to be critically discussed. It seems to be necessary to define thresholds based on specific performance tasks(strength vs. coordination related) rather than on generalizations,and age-related performance levels must be considered. Limb differences in unilateral leg extension strength represent a significant injury risk factor in youth ski racers.展开更多
A proper operating strategy is helpful to improve the off-design performance of combined cooling,heating and power(CCHP)systems,providing high efficiency and low emission.The energy level difference graphic analysis m...A proper operating strategy is helpful to improve the off-design performance of combined cooling,heating and power(CCHP)systems,providing high efficiency and low emission.The energy level difference graphic analysis method is used to identify energy level as well as exergy destruction of the part-load process.This method illustrates the energy efficiency upgrading mechanism of the flue gas reinjecting(FGR)operating strategy.It is referenced to a reducing turbine inlet temperature(TIT)operating strategy.By comparison,the FGR operating strategy leads to a 2.62%exergy distribution reduction in a gas turbine at an 85%load level due to the decrease of the energy level difference.When the output power is reduced further,the FGR operating strategy is supplanted by the TIT operating strategy with the limit of compressor inlet temperature.However,the opposite results of exergy distribution are presented in the exhaust-heat recovery devices.A heat-driven refrigeration and power cycle is introduced in a typical CCHP system as a solution.Moreover,the results suggest that the operational flexibility of the CCHP system is improved by enlarging the ratio of cooling to electricity.展开更多
The aim of this research lies on comparing anxiety body image profiles between male and female university students. A total sample of 2089 freshmen—902 women and 1187 men is from the different degrees offered by the ...The aim of this research lies on comparing anxiety body image profiles between male and female university students. A total sample of 2089 freshmen—902 women and 1187 men is from the different degrees offered by the Autonomous University of Chihuahua, with an average age of 18.23 ± 0.74 years. The approach used in the research is part of a quantitative design with a survey description. The differences found between men and women regarding their own perception of anxiety suggest that when designing any kind of intervention that aims at the decreasingly perceived anxiety, the gender variable will have to be taken into account. Future investigations should respond to these discoveries in larger samples.展开更多
The objective of the present experimental work is to investigate the performance of a wrapped screen heat pipe for atmospheric air heating to compare with the limits of this pipe. The experiment was conducted using co...The objective of the present experimental work is to investigate the performance of a wrapped screen heat pipe for atmospheric air heating to compare with the limits of this pipe. The experiment was conducted using copper pipe material and acetone as working fluid at different vapor temperatures. The testing also consists of a heater, a blower for heat removal (condenser), temperature measuring device, a vapor temperature probe, acetone charging system, and a vacuum pump. The copper outside diameterof the pipe is 0.022 m, with a total length of 0.6 m. The results showed that the pipe wall temperature (Tw) for a wrapped screen heat pipe has a rapid increase and takes 50 min to reach steady state at (Q = 63 W). The vapour temperature of working fluid increases as the heat load increases at constant air velocity. It was also been found that the range of vapour temperature deceases as the filling ratio increases that means the increasing of the filling ratio results the decrease of the maximum vapour temperature and the variation in the vapour temperature. The best recorded filling ratio is 0.6 which has the lowest vapour temperature at highest heat load. The maximum heat transport limit for this pipe is 80 W and the maximum temperature difference for air is 5。C.展开更多
The effects of green high performance concrete (GHPC) admixture on the anti-chloride permeability and anti- chloride corrodibility of concrete are studied by a series of experiments designed on the basis of the diffus...The effects of green high performance concrete (GHPC) admixture on the anti-chloride permeability and anti- chloride corrodibility of concrete are studied by a series of experiments designed on the basis of the diffusion principle and electro-chemical principle. The GHPC admixture consists of fly ash, gangue, slag, red mud, etc., of which the mass fraction of industrial residues is over 96 %. The anti-permeabilities and anti-corrodibilities of the tested GHPC and normal concrete (NC) are evaluated by the Diffusion Coefficients of chloride which was obtained by measuring the concentration of chloride in the tested systems by the voltage difference method. It is found that the adoption of GHPC admixture greatly improves the anti-chloride permeability and anti-chloride corrodibility by modifying the inner structure and contracting the porosity of concrete to the reduce considerably the diffusion rate of chloride. The admixture is desirable regarding its engineering performances as well as economical and environmental interests.展开更多
In this study,we estimated the weekly Gravity Recovery and Climate Experiment(GRACE)spherical harmonic(SH)solutions and regional mascon solutions using GRACE-based Geopotential Difference(GPD)data and investigated the...In this study,we estimated the weekly Gravity Recovery and Climate Experiment(GRACE)spherical harmonic(SH)solutions and regional mascon solutions using GRACE-based Geopotential Difference(GPD)data and investigated their abilities in retrieving terrestrial water storage(TWS)changes over the Amazon River Basin(ARB)from January 2003 to February 2013.The performance of the weekly GPD-SH and GPDmascon solutions was evaluated by comparing them with the weekly GFZ-SH solutions,Global Land Data Assimilation Systems(GLDAS)-NOAH hydrological model outputs,and monthly GFZ-SH,GPD-SH,and CSRmascon solutions in the spatio-temporal and spectral domains.The results demonstrate that the weekly GPD-SH and GPD-mascon present good consistency with the weekly GFZ-SH solutions and GLDAS-NOAH estimates in the spatio-temporal domains,but GPD-mascon presents stronger signal amplitudes and more spatial details.The comparison of the monthly average of weekly estimates and monthly solutions demonstrates that the weekly GPD-mascon and GFZ-SH with DDK1 filtering are close to the monthly CSRmascon and GFZ-SH solutions,respectively.However,the signal amplitudes of TWS changes from GPD-SH and GFZ-SH with 650 km Gaussian filtering are smaller than the monthly solutions,and the corresponding Root Mean Square Errors between the TWS change time series from the monthly average of weekly solutions and monthly estimates are 18.12 mm(GPD-mascon),18.81 mm(GFZ-SH-DDK1),24.93 mm(GPDSH-G650km),and 33.07 mm(GFZ-SH-G650km),respectively.Additionally,the TWS change time series derived from weekly solutions present more high-frequency time-varying information than monthly solutions.Furthermore,the 300 km Gaussian filtering can improve the signal amplitudes of TWS changes from the weekly GPD-SH solutions more than those with 650 km Gaussian filtering,but the corresponding noise level is higher.The weekly GPD-SH and GPD-mascon solutions can extend the application scopes of GRACE and provide good complements to the current GRACE monthly solutions.展开更多
Mathematical model of cross type multi-stream plate-fin heat exchanger is established.Meanwhile,mean square error of accumulative heat load is normalized by dimensionless,and the equations of temperature-difference un...Mathematical model of cross type multi-stream plate-fin heat exchanger is established.Meanwhile,mean square error of accumulative heat load is normalized by dimensionless,and the equations of temperature-difference uniformity factor are improved.Evaluation factors above and performance of heat exchanger are compared and analyzed by taking aircraft three-stream condenser as an example.The results demonstrate that the mean square error of accumulative heat load is common result of total heat load and excess heat load between passages.So it can be influenced by passage arrangement,flow inlet parameters as well as flow patterns.Dimensionless parameter of mean square error of accumulative heat load can reflect the influence of passage arrangement to heat exchange performance and will not change dramatically with the variation of flow inlet parameters and flow patterns.Temperature-difference uniformity factor is influenced by passage arrangement and flow patterns.It remains basically unchanged under a certain range of flow inlet parameters.展开更多
基金the support of the National Natural Science Foundation of China (Grant No.62204030)supported in part by the National Natural Science Foundation of China (Grant Nos.62122036,62034004,61921005,61974176,and 12074176)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDB44000000)。
文摘InSe has emerged as a promising candidate for next-generation electronics due to its predicted ultrahigh electrical performance.However,the efficacy of the InSe transistor in meeting application requirements is hindered due to its sensitivity to interfaces.In this study,we have achieved notable enhancement in the electrical performance of InSe transistors through interface engineering.We engineered an InSe/h-BN heterostructure,effectively suppressing dielectric layer-induced scattering.Additionally,we successfully established excellent metal-semiconductor contacts using graphene ribbons as a buffer layer.Through a methodical approach to interface engineering,our graphene/InSe/h-BN transistor demonstrates impressive on-state current,field-effect mobility,and on/off ratio at room temperature,reaching values as high as 1.1 mA/μm,904 cm^(2)·V^(-1)·s^(-1),and>10~6,respectively.Theoretical computations corroborate that the graphene/InSe heterostructure shows significant interlayer charge transfer and weak interlayer interaction,contributing to the enhanced performance of InSe transistors.This research offers a comprehensive strategy to elevate the electrical performance of InSe transistors,paving the way for their utilization in future electronic applications.
文摘This paper presents an investigation on the effect of JPEG compression on the similarity between the target image and the background,where the similarity is further used to determine the degree of clutter in the image.Four new clutter metrics based on image quality assessment are introduced,among which the Haar wavelet-based perceptual similarity index,known as HaarPSI,provides the best target acquisition prediction results.It is shown that the similarity between the target and the background at the boundary between visually lossless and visually lossy compression does not change significantly compared to the case when an uncompressed image is used.In future work,through subjective tests,it is necessary to check whether this presence of compression at the threshold of just noticeable differences will affect the human target acquisition performance.Similarity values are compared with the results of subjective tests of the well-known target Search_2 database,where the degree of agreement between objective and subjective scores,measured through linear correlation,reached a value of 90%.
基金Supported by National Natural Science Foundation of China(Grant Nos.71071032,71271053)
文摘Color coding is often used to enhance decision quality in complex man-machine interfaces of integrated display systems. However, people are easily distracted by irrelevant colors and by the numerous data points and complex structures in the interface. Although an increasing number of studies are seriously focusing on the problem of achieving efficient color coding, few are able to determine the effects of target and distractor saturations on cognitive performance. To study the performances of target colors among distractors, a systematic experiment is conducted to assess the influence of high and low saturated targets on cognitive performance, and the affecting extent of different saturated distractors of homogeneous colors on targets. According to the analysis of the reaction time through the non-parametric statistical method, a calculation method of the cognitive performance of each color is proposed. Based on the calculation of the color differences and the accumulation of the reaction times, it is shown that with the different saturated distractors of homogeneous colors, the high saturated yellow targets perform better than the low saturated ones, and the green and blue targets have moderate performances. When searching for a singleton target placed oll a black background, the color difference between the target and the distractor should be more than 20AE*ab units in the yellow saturation coding, whereas the color difference should be more than 40△E*ab units in the blue and green saturation coding. In addition, as regards saturation coding, the influence of the color difference between the target and the background on cognitive performance is greater than that of the color difference between the target and the distractor. Seemingly, the hue attribute determines whether the saturation difference between the target and the distractor affects thc cognitive performance. Based on the experimental results, the simulation design of the instrument dials in a flight situation awareness interface is completed and tested. Simulation results show the feasibility of the method of choosing the target and distractor colors, and the proposed research provides the instruction for the color saturation design of the interface.
基金financial support from the Overseas Expertise Introduction Project for Discipline Innovation (B16031)the National Natural Science Foundation of China (71703084)the Fundamental Research Funds for the Central Universities (2017CSZ021)
文摘This study investigates the impact of parental labor migration on the academic achievements and non-academic growth of left-behind children in fourth and seventh grades. Employing survey data collected from rural China in 2014, 2015, and 2016, we examine the effect of parental absence on children's academic achievement using Propensity Score Matching(PSM) and Difference in Difference(DID) methods. The results demonstrate that left-behind children whose parents have migrated for one year have statistically significantly lower academic scores. Academic scores drop lower for fourthgrade students and students from higher-income families. There are also adverse effects on left-behind children's confidence, teacher-student relationships, subjective well-being, and educational expectations if parents migrate for one year. Surprisingly, if parental migration lasts longer(totaling two years), these adverse effects disappear, and student's educational expectations even improve. These results may be because, over time, the adverse effects that occur immediately after parental migration are offset by the positive effects of migration(i.e. higher income). These conclusions can inform migrant parents on ways to utilize their resources to improve the academic performance of their left-behind children.
文摘Assessment of performance of China's sports industry is not only favorable for grasping development level of sports industry,but also able to,from micro perspective,find out factors influencing development of sports industry and their contribution to development of sports industry. Through selecting quantitative indicators for development of sports industry,the authors analyzed performance of development of sports industry in China and analyzed regional difference of sports industry by the data envelopment analysis( DEA) method. The study indicated that( i) performance of sports industry in recent years takes on growth trend,which may give the credit to scientific and technological progress;( ii) the development of sports industry in China has distinct spatial difference,best in eastern regions,better in middle regions,and poor in western regions.
文摘Purpose: The aims of this study were to assess differences of limb symmetry index(LSI) in strength-and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related performance levels and to prospectively assess limb differences as a possible risk factor for traumatic and overuse injury in youth ski racers.Methods: The study(Study 1) included 285 high-level competitive ski racers(125 females, 160 males) of 3 age-related performance levels and based on the school system: 95 youth(10à14 years, secondary modern school), 107 adolescent(15à19 years, grammar school), and 83 elite athletes(20à34 years). To investigate the second aim(Study 2), 67 of the 95 youth athletes were included and any traumatic or overuse injuries were prospectively recorded over 2 seasons. All athletes performed 4 unilateral tests(strength related: one-leg counter movement jump(OL-CMJ) and one-leg isometric/isokinetic press strength test(OL-ILS); coordination related: one-leg stability test(OL-ST) and one-leg speedy jump test(OL-SJ)). The LSI was calculated by dividing the dominant leg by the nondominant leg and multiplying by 100. Kruskal-Wallis H tests and binary logistic regression analyses were conducted.Results: There were significant differences between the LSI of the 3 age-related performance-level groups only in the strength-related tests: the OL-CMJ(x2(2, 285) = 9.09; p = 0.01) and the OL-ILS(x2(2, 285) = 14.79; p < 0.01). The LSI for OL-ILS was found to be a significant risk factor for traumatic injury in youth ski racers(Wald = 7.08; p < 0.01). No significant risk factors were found for overuse injuries.Conclusion: Younger athletes display slightly greater LSI values only in the strength-related tests. The cut-off value of limb differences of <10%for return to sport decisions seems to be appropriate for elite athletes, but for youth and adolescent athletes it has to be critically discussed. It seems to be necessary to define thresholds based on specific performance tasks(strength vs. coordination related) rather than on generalizations,and age-related performance levels must be considered. Limb differences in unilateral leg extension strength represent a significant injury risk factor in youth ski racers.
基金supported by the National Natural Science Foundation of China(Grant No.52006213)。
文摘A proper operating strategy is helpful to improve the off-design performance of combined cooling,heating and power(CCHP)systems,providing high efficiency and low emission.The energy level difference graphic analysis method is used to identify energy level as well as exergy destruction of the part-load process.This method illustrates the energy efficiency upgrading mechanism of the flue gas reinjecting(FGR)operating strategy.It is referenced to a reducing turbine inlet temperature(TIT)operating strategy.By comparison,the FGR operating strategy leads to a 2.62%exergy distribution reduction in a gas turbine at an 85%load level due to the decrease of the energy level difference.When the output power is reduced further,the FGR operating strategy is supplanted by the TIT operating strategy with the limit of compressor inlet temperature.However,the opposite results of exergy distribution are presented in the exhaust-heat recovery devices.A heat-driven refrigeration and power cycle is introduced in a typical CCHP system as a solution.Moreover,the results suggest that the operational flexibility of the CCHP system is improved by enlarging the ratio of cooling to electricity.
文摘The aim of this research lies on comparing anxiety body image profiles between male and female university students. A total sample of 2089 freshmen—902 women and 1187 men is from the different degrees offered by the Autonomous University of Chihuahua, with an average age of 18.23 ± 0.74 years. The approach used in the research is part of a quantitative design with a survey description. The differences found between men and women regarding their own perception of anxiety suggest that when designing any kind of intervention that aims at the decreasingly perceived anxiety, the gender variable will have to be taken into account. Future investigations should respond to these discoveries in larger samples.
文摘The objective of the present experimental work is to investigate the performance of a wrapped screen heat pipe for atmospheric air heating to compare with the limits of this pipe. The experiment was conducted using copper pipe material and acetone as working fluid at different vapor temperatures. The testing also consists of a heater, a blower for heat removal (condenser), temperature measuring device, a vapor temperature probe, acetone charging system, and a vacuum pump. The copper outside diameterof the pipe is 0.022 m, with a total length of 0.6 m. The results showed that the pipe wall temperature (Tw) for a wrapped screen heat pipe has a rapid increase and takes 50 min to reach steady state at (Q = 63 W). The vapour temperature of working fluid increases as the heat load increases at constant air velocity. It was also been found that the range of vapour temperature deceases as the filling ratio increases that means the increasing of the filling ratio results the decrease of the maximum vapour temperature and the variation in the vapour temperature. The best recorded filling ratio is 0.6 which has the lowest vapour temperature at highest heat load. The maximum heat transport limit for this pipe is 80 W and the maximum temperature difference for air is 5。C.
文摘The effects of green high performance concrete (GHPC) admixture on the anti-chloride permeability and anti- chloride corrodibility of concrete are studied by a series of experiments designed on the basis of the diffusion principle and electro-chemical principle. The GHPC admixture consists of fly ash, gangue, slag, red mud, etc., of which the mass fraction of industrial residues is over 96 %. The anti-permeabilities and anti-corrodibilities of the tested GHPC and normal concrete (NC) are evaluated by the Diffusion Coefficients of chloride which was obtained by measuring the concentration of chloride in the tested systems by the voltage difference method. It is found that the adoption of GHPC admixture greatly improves the anti-chloride permeability and anti-chloride corrodibility by modifying the inner structure and contracting the porosity of concrete to the reduce considerably the diffusion rate of chloride. The admixture is desirable regarding its engineering performances as well as economical and environmental interests.
基金funded by the National Natural Science Foundation of China(Nos.41974015,42374002)the Project Supported by the Special Fund of Hubei Luojia Laboratory(No.220100004)。
文摘In this study,we estimated the weekly Gravity Recovery and Climate Experiment(GRACE)spherical harmonic(SH)solutions and regional mascon solutions using GRACE-based Geopotential Difference(GPD)data and investigated their abilities in retrieving terrestrial water storage(TWS)changes over the Amazon River Basin(ARB)from January 2003 to February 2013.The performance of the weekly GPD-SH and GPDmascon solutions was evaluated by comparing them with the weekly GFZ-SH solutions,Global Land Data Assimilation Systems(GLDAS)-NOAH hydrological model outputs,and monthly GFZ-SH,GPD-SH,and CSRmascon solutions in the spatio-temporal and spectral domains.The results demonstrate that the weekly GPD-SH and GPD-mascon present good consistency with the weekly GFZ-SH solutions and GLDAS-NOAH estimates in the spatio-temporal domains,but GPD-mascon presents stronger signal amplitudes and more spatial details.The comparison of the monthly average of weekly estimates and monthly solutions demonstrates that the weekly GPD-mascon and GFZ-SH with DDK1 filtering are close to the monthly CSRmascon and GFZ-SH solutions,respectively.However,the signal amplitudes of TWS changes from GPD-SH and GFZ-SH with 650 km Gaussian filtering are smaller than the monthly solutions,and the corresponding Root Mean Square Errors between the TWS change time series from the monthly average of weekly solutions and monthly estimates are 18.12 mm(GPD-mascon),18.81 mm(GFZ-SH-DDK1),24.93 mm(GPDSH-G650km),and 33.07 mm(GFZ-SH-G650km),respectively.Additionally,the TWS change time series derived from weekly solutions present more high-frequency time-varying information than monthly solutions.Furthermore,the 300 km Gaussian filtering can improve the signal amplitudes of TWS changes from the weekly GPD-SH solutions more than those with 650 km Gaussian filtering,but the corresponding noise level is higher.The weekly GPD-SH and GPD-mascon solutions can extend the application scopes of GRACE and provide good complements to the current GRACE monthly solutions.
文摘Mathematical model of cross type multi-stream plate-fin heat exchanger is established.Meanwhile,mean square error of accumulative heat load is normalized by dimensionless,and the equations of temperature-difference uniformity factor are improved.Evaluation factors above and performance of heat exchanger are compared and analyzed by taking aircraft three-stream condenser as an example.The results demonstrate that the mean square error of accumulative heat load is common result of total heat load and excess heat load between passages.So it can be influenced by passage arrangement,flow inlet parameters as well as flow patterns.Dimensionless parameter of mean square error of accumulative heat load can reflect the influence of passage arrangement to heat exchange performance and will not change dramatically with the variation of flow inlet parameters and flow patterns.Temperature-difference uniformity factor is influenced by passage arrangement and flow patterns.It remains basically unchanged under a certain range of flow inlet parameters.