The rapid development of the digital economy has provided a new impetus for rural residents to extend their working hours.Based on the data collected by the China Labor-force Dynamics Survey(CLDS)in 2014,2016,and 2018...The rapid development of the digital economy has provided a new impetus for rural residents to extend their working hours.Based on the data collected by the China Labor-force Dynamics Survey(CLDS)in 2014,2016,and 2018,this paper measured the development level of the digital economy in China from the perspectives of internet development and digital financial inclusion,and tested the mechanisms of how the digital economy affected rural residents’working hours.The results showed that the digital economy extended rural residents’working hours by expanding information channels and enhancing human capital,and this mechanism was affected by heterogeneity in rural residents’educational background,age,and social capital.Building on these findings,this paper holds that to increase rural residents’income by extending their working hours and achieving common prosperity for all,it is necessary to expand the opportunities for rural residents to participate in skills training and promote their accumulation of human capital.展开更多
There is considerable concern about the potential impact of climate change on agriculture, such as the accumulation of chilling hours needed to break the dormancy of many perennial plants, like fruit trees. Therefore,...There is considerable concern about the potential impact of climate change on agriculture, such as the accumulation of chilling hours needed to break the dormancy of many perennial plants, like fruit trees. Therefore, this study aimed to determine if there had been a significant change in air temperatures and chill hours, chill units, and chill portion accumulation in South Carolina over the last two decades. Two decades of daily maximum (T<sub>max</sub>) and minimum (T<sub>min</sub>) air temperature records were obtained from weather stations in thirty-one counties in South Carolina. Hourly temperature data, reconstructed from the daily data, were used to calculate the daily and annual chill hours, chill units, and chill portions accumulation using four different chill models for each location and year. The chill models included the T(t) °C model, the 0°C °C model, the Utah model, and the Dynamic model. For each county, regression analyses were conducted to evaluate the historical trends. Despite year-to-year variability, the tendency was a statistically significant (α = 0.05) increase in air temperature, averaging 0.089°C per year for 20 out of 31 counties in South Carolina. The other 11 counties had no significant change in temperature. The average temperature increase in the 31 counties was 0.072°C per year. The temperature increase resulted in a decrease in annual chill accumulation during the fall to spring, averaging 17.7 chill hours, 8.6 chill hours, 17.0 chill units, and 0.40 chill portions per year calculated with the T(t) °C, 0°C °C, Utah, and Dynamic models, respectively. However, whether this decrease in chill values was statistically significant or not depended on the chill model used. This study did not investigate the cause of the observed historical trends in temperature and chill accumulation. Still, if the trends continue, they could significantly impact the future of the temperate fruit tree industry in the state.展开更多
In order to ease congestion and ground delays in major hub airports, an aircraft taxiing scheduling optimization model is proposed with schedule time as the object function. In the new model, the idea of a classical j...In order to ease congestion and ground delays in major hub airports, an aircraft taxiing scheduling optimization model is proposed with schedule time as the object function. In the new model, the idea of a classical job shop-schedule problem is adopted and three types of special aircraft-taxi conflicts are considered in the constraints. To solve such nondeterministic polynomial time-complex problems, the immune clonal selection algorithm(ICSA) is introduced. The simulation results in a congested hour of Beijing Capital International Airport show that, compared with the first-come-first-served(FCFS) strategy, the optimization-planning strategy reduces the total scheduling time by 13.6 min and the taxiing time per aircraft by 45.3 s, which improves the capacity of the runway and the efficiency of airport operations.展开更多
Background Increased levels of inflammatory markers have been documented in various settings of coronary artery disease. The vulnerability of coronary lesions in acute myocardial infarction(AMI) at the time of onset m...Background Increased levels of inflammatory markers have been documented in various settings of coronary artery disease. The vulnerability of coronary lesions in acute myocardial infarction(AMI) at the time of onset may be related to serum levels of C reactive protein(CRP) on admission, before CRP levels are affected by myocardial damage.Objective This study assessed the predictive value of CRP levels within six hours after the onset of acute anterior myocardial infarction with primary percutaneous coronary intervention(PCI).Methods The plasma CRP of 76 patients with first acute anterior myocardial infarction was measured within 6 hours after onset. They were divided into 2 groups: group 1( n =20) with elevated CRP( ≥0.3mg/dl ) on admission within 6 hours after onset and group 2( n =56) with normal CRP( <0.3mg/dl ) within 6 hours after onset. All patients were treated by primary PCI. The primary combined end points, including death due to cardiac causes, re MI related to the infarction artery(RIA) and repeat intervention of the RIA, and the restenosis rate were assessed in relation to CRP levels within 6 hours after onset. Left ventricular end diastolic volume index(EDVI),end systolic volume index(ESVI),and ejection fraction(EF) on admission and 6 month after the onset were assessed by left ventriculography. Changes in EDVI(ΔEDVI),ESVI(ΔESVI), and EF(ΔEF) were obtained by subtracting respective on admission values from corresponding 6 month follow up values. Results There were no significant differences in baseline characteristics between the two groups. The primary combined end points were significantly more frequent in group 1(20%) than those in group 2( 1.79% , P <0.01 ).In addition, restenosis rates were significantly higher in group 1 than in group 2(41.18% vs 16.07%, P<0.05). Group 1 showed greater increases in left ventricular volume and less improvement in EF compared with group 2(ΔEDVI 6.31 ±2.17 vs 3.29 ±9.46ml/m 2 , ΔESVI 5.92 ±2.31 vs 3.86 ±1.08ml/m 2 , ΔEF 1.92 ±0.47 vs 4.79 ±1.73% , P <0.05 , respectively).Conclusions CRP levels within 6 hours after the onset of AMI might predict adverse outcome after primary PCI and progressive ventricular remodeling within 6 month of AMI.展开更多
Background/Aims: Juvenile myopia is a serious problem in China, the prevalence of which stays at a high level and shows an upward trend. The target of this study was to explore the factors associated with myopia in Ch...Background/Aims: Juvenile myopia is a serious problem in China, the prevalence of which stays at a high level and shows an upward trend. The target of this study was to explore the factors associated with myopia in Chinese children. Methods: A cross-sectional analysis in a random sample survey was conducted in Beijing in 2008. The data collected from 15,316 Chinese school students aged 6 to 18 years, randomly selected from 19 schools were evaluated, including noncycloplegic refraction and possible genetic, environmental and behavioral factors, to explore the key risk factors for myopia. Univariate and multiple logistic regression analyses were performed to compare the OR values, and receiver operator characteristic (ROC) curves were generated to compare the differences among the areas under the ROC curves using the method of multiple comparison with the best. Results: Myopia was associated with shorter sleep times versus longer sleep times (adjusted OR = 3.37;95%CI 3.07-3.70), and the multivariate OR for two compared with no parents with myopic was 2.83 (95%CI 2.47-3.24) and 1.95 (95%CI 1.69-2.24) for reading or writing distances less than33 cmcompared to distances greater than33 cm. Controlling for other factors, children that slept for shorter periods of time had significantly more myopic refractions (?1.69D vs ?1.29D for children with longer sleeping time per day). Analysis of the areas under the ROC curves showed five variables with predictable values better than chance: age, sleeping time, reading or writing distance, hours of studying, and parental myopia. Conclusion: It was not surprising, as proved by other studies, that parental myopia, reading or writing distances, time spent on studying or other activities by using eyes were dominant risk factors associated with juvenile myopia. Our findings indicated that hours of sleeping were also closely related to juvenile myopia, in which the underlying mechanism should be explored in the future study.展开更多
Winter chill is essential for the growth and development of deciduous species. To understand the relationship between accumulated chilling hours during endodormancy and blooming and fruit shape development, we control...Winter chill is essential for the growth and development of deciduous species. To understand the relationship between accumulated chilling hours during endodormancy and blooming and fruit shape development, we controlled chilling hours and investigated their effects on blooming date and fruit shape of peaches. The results showed that the number of days to full bloom date and the heat requirement for blooming were negatively correlated with accumulated chilling hours. Accumulated chilling hours were significantly negatively correlated with fruit shape index and fruit tip lengths, suggesting that the number of chilling hours affect the fruit shape development. Fewer accumulated chilling hours may be the major reason for longer fruit shape and protruding fruit tips. In conclusion, our results indicate specifically that decreased winter chilling hours can delay the bloom date and may lead to aberrant fruit shape development in peaches. Our study provides preliminary insights into the response of temperate fruit species to global climate change.展开更多
[Objective] The aim was to analyze the changes characteristics of sunshine hours of Dalian City. [Method] Based on the data of sunshine hours of Dalian City during 1951 to 2009 and by dint of linear estimation and acc...[Objective] The aim was to analyze the changes characteristics of sunshine hours of Dalian City. [Method] Based on the data of sunshine hours of Dalian City during 1951 to 2009 and by dint of linear estimation and accumulation anomaly, the change characteristics of decade, annual, seasonal, monthly sunshine hours in Dalian City were analyzed. [Result] The change characteristics of decade, annual, seasonal, monthly sunshine hours in Dalian City were in a decrease trend since recent 59 years. The average sunshine hour in 1950s was the maximum one. Since 21st century, the annual sunshine hour was the lowest one. Annual average sunshine hours were the highest in 1978, and lowest in 2003. There were more sunshine hours before 1989 and later less. Among the four seasons, the sunshine hours in autumn decreased fastest and slowest in spring. The monthly average sunshine hours were the most in May and least in December; the sunshine hours in each month decreased fastest in July. It showed increasing tendency only in March. [Conclusion] The study supplied scientific reference for the reasonable utilization of light energy, agricultural production structure and sustainable development of agricultural economy.展开更多
[Objective] The research aimed to analyze the variation characteristics of sunshine hours in Puyang City in recent 51 years.[Method] Based on the monthly sunshine hours in five meteorological stations of Puyang City d...[Objective] The research aimed to analyze the variation characteristics of sunshine hours in Puyang City in recent 51 years.[Method] Based on the monthly sunshine hours in five meteorological stations of Puyang City during 1960-2010,the annual,seasonal and monthly variation trends of sunshine hours,mutation time node were analyzed by using the climate trend coefficient,climate tendency rate,sliding average method,SNR and so on.The objective fact and rule of sunshine variation in Puyang in recent 51 years were revealed.[Result] The annual sunshine hours presented the decline trend in Puyang City in recent 51 years,and the decline range was-14.30 h/a.The seasonal sunshine hours presented the decline trend over the years,and the decline range was during-0.66 and-1.89 h/a.The maximum decline range was-1.89 h/a in summer.The monthly sunshine hours presented the decline trend over the years,and the decline range was during-21.51 and-2.13 h/a.The maximum decline range was-21.51 h/a in July.The annual sunshine hours had one mutation in 1983.The sunshine hours was more in the 1960s and 1970s.In the middle and late periods of 1980s,the sunshine hours was relatively less.[Conclusion] The research provided the guidance value for the adjustment of plantation structure and the transformation of agricultural developed manner in Puyang City.展开更多
[Objective]The research aimed to study climatic change characteristics of sunshine hours in Lianyungang and analyze its formation reason. [Method]Based on monthly sunshine hours,precipitation,cloudiness,haze days and ...[Objective]The research aimed to study climatic change characteristics of sunshine hours in Lianyungang and analyze its formation reason. [Method]Based on monthly sunshine hours,precipitation,cloudiness,haze days and vapor pressure from 7 stations of Lianyungang from 1961 to 2010,monthly,seasonal,annual and interdecadal change trends of the sunshine hours were analyzed by using MK test,linear trend analysis and Morlet wavelet. Meanwhile,the cause of change characteristics was analyzed. [Result] Monthly sunshine hours of Lianyungang showed bimodal distribution,and seasonal and annual sunshine hours had decreasing trend at different degrees. The interdecadal change of sunshine hours showed wave characteristics. The annual sunshine hours had multiple temporal-spatial scale features,and there was an obvious mutation in the late 1980s. Sunshine hours in Lianyungang was closely related to visibility,cloudiness,vapor pressure and haze,and they were important factors causing that sunshine hours significantly declined. [Conclusion]The research could provide reference basis for scientifically developing and using solar energy resource and reasonably adjusting industrial and agricultural structures.展开更多
Rational and accurate solar energy databases, essential for designing, sizing and performing the solar energy systems in any part of the world, are not easily accessible in different localities of Nepal. In this study...Rational and accurate solar energy databases, essential for designing, sizing and performing the solar energy systems in any part of the world, are not easily accessible in different localities of Nepal. In this study, daily global solar radiation, sunshine hours and meteorological data for Biratnagar, Kathmandu, Pokhara and Jumla have been used to derive the regression constants. The linear regression technique has been used to develop a model for Biratnagar, Kathmandu, Pokhara and Jumla. The model has calculated the global solar radiation for these locations. The values of global solar radiation estimated by the model are found to be in close agreement with measured values of respective sites. The estimated values were compared with Angstrom-Prescott model and examined using the root mean square error (RMSE), mean bias error (MBE), mean percentage error (MPE), coefficient of regression (R), coefficient of determinant (R2) and correlation coefficient (CC) statistical techniques. Thus, the resultant correlations and linear regression relations may be then used for the locations of similar meteorological/geographical characteristics and also can be used to estimate the missing data of solar radiation for the respective site.展开更多
To improve the accuracy of capacity analysis and prediction for the aircraft assembly stations,an approach for calculating the effective working hour(EWH)of automatic assembly equipment is introduced by using the dyna...To improve the accuracy of capacity analysis and prediction for the aircraft assembly stations,an approach for calculating the effective working hour(EWH)of automatic assembly equipment is introduced by using the dynamic mixed Weibull distribution(DMWD)model.Firstly,according to the features of aircraft assembling,a DMWD model considering the dynamic reliability of multiple subsystems and their synthetic effects on the whole equipment is established.A typical automatic drilling&riveting machine is selected as the research object,and the dynamic weights of reliability of three subsystems are modeled and solved.Subsequently the unknown parameters of the DMWD model are estimated based on maximum likelihood estimation(MLE)and Newton-Raphson method.Finally,the EWH of an automatic station is defined and modeled by using the solved dynamic reliability function.Based on the experimental study on a real automatic drilling&riveting machine from a wing panel assembly station,it is shown that the proposed DMWD and EWH models could effectively calculate the equipment reliability with full consideration of its multiple subsystems.The DMWD model is more suitable for improving the solution precision of EWH than the traditional three-parameter Weibull distribution.展开更多
The present study aims to conduct 2 types of statistical analysis to reveal the impact of the spread of COVID-19 on train delays by comparing the potential contributing factors before, during and after the outbreak of...The present study aims to conduct 2 types of statistical analysis to reveal the impact of the spread of COVID-19 on train delays by comparing the potential contributing factors before, during and after the outbreak of the virus in the metropolitan train lines in Japan. First of all, the result of the present study clearly revealed the changes in contributing factors for train delays caused by the spread of COVID-19. Specifically, the contributing factors for train delays changed due to the decrease of passengers by the effect of the outbreak of the virus. Additionally, though large terminal stations were considered to be a major contributing factor in causing and increasing train delays in the past, this was not the case after the spread of COVID-19. Therefore, under such conditions, it is more effective to make improvements in small to medium stations and tracks rather than terminal stations. Furthermore, as the decrease in passengers also decreased train delays in commuter lines going to the suburbs due to the spread of COVID-19, the contributing factor for such lines is the excessive number of passengers. Therefore, as for countermeasures for train delays after the effects of COVID-19, it is necessary to disperse passengers in order to avoid passengers concentrating in the same time zones and train lines.展开更多
The essay tries to explore the metafiction elements in Michael Cunningham’s novel The Hours.The work,The Hours,is in fact a fiction about how the fiction becomes a fiction and also a fiction about the previous fictio...The essay tries to explore the metafiction elements in Michael Cunningham’s novel The Hours.The work,The Hours,is in fact a fiction about how the fiction becomes a fiction and also a fiction about the previous fiction,Mrs.Dalloway.Through the deconstruction of the previous work,the reality and history are re-defined by The Hours.展开更多
In A Room of One's Own,Virginia Woolf argued her famous proposition that a woman needed to have a room of her own to achieve literary autonomy,and laid the foundation for present-day feminist criticism.Yet the aut...In A Room of One's Own,Virginia Woolf argued her famous proposition that a woman needed to have a room of her own to achieve literary autonomy,and laid the foundation for present-day feminist criticism.Yet the author believes that economic independent does not foster women's identity with certainty.In this thesis,the author explores the crucial place of spiritual and economic independence in building up women's autonomy through analyzing Michael Cunningham Pulitzerwinning work The Hours,which he draws inventively on the life of Virginia Woolf and her work Mrs.Dalloway.展开更多
基金This paper is part of the Youth Program of Science and Technology Research of Chongqing Municipal Education Commission(KJQN202300545)Youth Program of National Social Science Fund of China(21CJY001)Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202300567).
文摘The rapid development of the digital economy has provided a new impetus for rural residents to extend their working hours.Based on the data collected by the China Labor-force Dynamics Survey(CLDS)in 2014,2016,and 2018,this paper measured the development level of the digital economy in China from the perspectives of internet development and digital financial inclusion,and tested the mechanisms of how the digital economy affected rural residents’working hours.The results showed that the digital economy extended rural residents’working hours by expanding information channels and enhancing human capital,and this mechanism was affected by heterogeneity in rural residents’educational background,age,and social capital.Building on these findings,this paper holds that to increase rural residents’income by extending their working hours and achieving common prosperity for all,it is necessary to expand the opportunities for rural residents to participate in skills training and promote their accumulation of human capital.
文摘There is considerable concern about the potential impact of climate change on agriculture, such as the accumulation of chilling hours needed to break the dormancy of many perennial plants, like fruit trees. Therefore, this study aimed to determine if there had been a significant change in air temperatures and chill hours, chill units, and chill portion accumulation in South Carolina over the last two decades. Two decades of daily maximum (T<sub>max</sub>) and minimum (T<sub>min</sub>) air temperature records were obtained from weather stations in thirty-one counties in South Carolina. Hourly temperature data, reconstructed from the daily data, were used to calculate the daily and annual chill hours, chill units, and chill portions accumulation using four different chill models for each location and year. The chill models included the T(t) °C model, the 0°C °C model, the Utah model, and the Dynamic model. For each county, regression analyses were conducted to evaluate the historical trends. Despite year-to-year variability, the tendency was a statistically significant (α = 0.05) increase in air temperature, averaging 0.089°C per year for 20 out of 31 counties in South Carolina. The other 11 counties had no significant change in temperature. The average temperature increase in the 31 counties was 0.072°C per year. The temperature increase resulted in a decrease in annual chill accumulation during the fall to spring, averaging 17.7 chill hours, 8.6 chill hours, 17.0 chill units, and 0.40 chill portions per year calculated with the T(t) °C, 0°C °C, Utah, and Dynamic models, respectively. However, whether this decrease in chill values was statistically significant or not depended on the chill model used. This study did not investigate the cause of the observed historical trends in temperature and chill accumulation. Still, if the trends continue, they could significantly impact the future of the temperate fruit tree industry in the state.
基金Supported by the Basic Scientific Research Projects of the Central University of China(ZXH2010D010)the National Natural Science Foundation of China(60979021/F01)~~
文摘In order to ease congestion and ground delays in major hub airports, an aircraft taxiing scheduling optimization model is proposed with schedule time as the object function. In the new model, the idea of a classical job shop-schedule problem is adopted and three types of special aircraft-taxi conflicts are considered in the constraints. To solve such nondeterministic polynomial time-complex problems, the immune clonal selection algorithm(ICSA) is introduced. The simulation results in a congested hour of Beijing Capital International Airport show that, compared with the first-come-first-served(FCFS) strategy, the optimization-planning strategy reduces the total scheduling time by 13.6 min and the taxiing time per aircraft by 45.3 s, which improves the capacity of the runway and the efficiency of airport operations.
文摘Background Increased levels of inflammatory markers have been documented in various settings of coronary artery disease. The vulnerability of coronary lesions in acute myocardial infarction(AMI) at the time of onset may be related to serum levels of C reactive protein(CRP) on admission, before CRP levels are affected by myocardial damage.Objective This study assessed the predictive value of CRP levels within six hours after the onset of acute anterior myocardial infarction with primary percutaneous coronary intervention(PCI).Methods The plasma CRP of 76 patients with first acute anterior myocardial infarction was measured within 6 hours after onset. They were divided into 2 groups: group 1( n =20) with elevated CRP( ≥0.3mg/dl ) on admission within 6 hours after onset and group 2( n =56) with normal CRP( <0.3mg/dl ) within 6 hours after onset. All patients were treated by primary PCI. The primary combined end points, including death due to cardiac causes, re MI related to the infarction artery(RIA) and repeat intervention of the RIA, and the restenosis rate were assessed in relation to CRP levels within 6 hours after onset. Left ventricular end diastolic volume index(EDVI),end systolic volume index(ESVI),and ejection fraction(EF) on admission and 6 month after the onset were assessed by left ventriculography. Changes in EDVI(ΔEDVI),ESVI(ΔESVI), and EF(ΔEF) were obtained by subtracting respective on admission values from corresponding 6 month follow up values. Results There were no significant differences in baseline characteristics between the two groups. The primary combined end points were significantly more frequent in group 1(20%) than those in group 2( 1.79% , P <0.01 ).In addition, restenosis rates were significantly higher in group 1 than in group 2(41.18% vs 16.07%, P<0.05). Group 1 showed greater increases in left ventricular volume and less improvement in EF compared with group 2(ΔEDVI 6.31 ±2.17 vs 3.29 ±9.46ml/m 2 , ΔESVI 5.92 ±2.31 vs 3.86 ±1.08ml/m 2 , ΔEF 1.92 ±0.47 vs 4.79 ±1.73% , P <0.05 , respectively).Conclusions CRP levels within 6 hours after the onset of AMI might predict adverse outcome after primary PCI and progressive ventricular remodeling within 6 month of AMI.
文摘Background/Aims: Juvenile myopia is a serious problem in China, the prevalence of which stays at a high level and shows an upward trend. The target of this study was to explore the factors associated with myopia in Chinese children. Methods: A cross-sectional analysis in a random sample survey was conducted in Beijing in 2008. The data collected from 15,316 Chinese school students aged 6 to 18 years, randomly selected from 19 schools were evaluated, including noncycloplegic refraction and possible genetic, environmental and behavioral factors, to explore the key risk factors for myopia. Univariate and multiple logistic regression analyses were performed to compare the OR values, and receiver operator characteristic (ROC) curves were generated to compare the differences among the areas under the ROC curves using the method of multiple comparison with the best. Results: Myopia was associated with shorter sleep times versus longer sleep times (adjusted OR = 3.37;95%CI 3.07-3.70), and the multivariate OR for two compared with no parents with myopic was 2.83 (95%CI 2.47-3.24) and 1.95 (95%CI 1.69-2.24) for reading or writing distances less than33 cmcompared to distances greater than33 cm. Controlling for other factors, children that slept for shorter periods of time had significantly more myopic refractions (?1.69D vs ?1.29D for children with longer sleeping time per day). Analysis of the areas under the ROC curves showed five variables with predictable values better than chance: age, sleeping time, reading or writing distance, hours of studying, and parental myopia. Conclusion: It was not surprising, as proved by other studies, that parental myopia, reading or writing distances, time spent on studying or other activities by using eyes were dominant risk factors associated with juvenile myopia. Our findings indicated that hours of sleeping were also closely related to juvenile myopia, in which the underlying mechanism should be explored in the future study.
基金supported by the grants from the Agricultural Science and Technology Innovation Program, China (CAAS-ASTIP-2015-ZFRI)the Comprehensive Experimental Station of Zhengzhou of China Agriculture Research System (CARS-31-Z-10)
文摘Winter chill is essential for the growth and development of deciduous species. To understand the relationship between accumulated chilling hours during endodormancy and blooming and fruit shape development, we controlled chilling hours and investigated their effects on blooming date and fruit shape of peaches. The results showed that the number of days to full bloom date and the heat requirement for blooming were negatively correlated with accumulated chilling hours. Accumulated chilling hours were significantly negatively correlated with fruit shape index and fruit tip lengths, suggesting that the number of chilling hours affect the fruit shape development. Fewer accumulated chilling hours may be the major reason for longer fruit shape and protruding fruit tips. In conclusion, our results indicate specifically that decreased winter chilling hours can delay the bloom date and may lead to aberrant fruit shape development in peaches. Our study provides preliminary insights into the response of temperate fruit species to global climate change.
文摘[Objective] The aim was to analyze the changes characteristics of sunshine hours of Dalian City. [Method] Based on the data of sunshine hours of Dalian City during 1951 to 2009 and by dint of linear estimation and accumulation anomaly, the change characteristics of decade, annual, seasonal, monthly sunshine hours in Dalian City were analyzed. [Result] The change characteristics of decade, annual, seasonal, monthly sunshine hours in Dalian City were in a decrease trend since recent 59 years. The average sunshine hour in 1950s was the maximum one. Since 21st century, the annual sunshine hour was the lowest one. Annual average sunshine hours were the highest in 1978, and lowest in 2003. There were more sunshine hours before 1989 and later less. Among the four seasons, the sunshine hours in autumn decreased fastest and slowest in spring. The monthly average sunshine hours were the most in May and least in December; the sunshine hours in each month decreased fastest in July. It showed increasing tendency only in March. [Conclusion] The study supplied scientific reference for the reasonable utilization of light energy, agricultural production structure and sustainable development of agricultural economy.
文摘[Objective] The research aimed to analyze the variation characteristics of sunshine hours in Puyang City in recent 51 years.[Method] Based on the monthly sunshine hours in five meteorological stations of Puyang City during 1960-2010,the annual,seasonal and monthly variation trends of sunshine hours,mutation time node were analyzed by using the climate trend coefficient,climate tendency rate,sliding average method,SNR and so on.The objective fact and rule of sunshine variation in Puyang in recent 51 years were revealed.[Result] The annual sunshine hours presented the decline trend in Puyang City in recent 51 years,and the decline range was-14.30 h/a.The seasonal sunshine hours presented the decline trend over the years,and the decline range was during-0.66 and-1.89 h/a.The maximum decline range was-1.89 h/a in summer.The monthly sunshine hours presented the decline trend over the years,and the decline range was during-21.51 and-2.13 h/a.The maximum decline range was-21.51 h/a in July.The annual sunshine hours had one mutation in 1983.The sunshine hours was more in the 1960s and 1970s.In the middle and late periods of 1980s,the sunshine hours was relatively less.[Conclusion] The research provided the guidance value for the adjustment of plantation structure and the transformation of agricultural developed manner in Puyang City.
基金Supported by Meteorological Youth Fund of Jiangsu Province,China(Q201104)the Project of Science and Technology Bureau in Lianyungang of Jiangsu Province,China(SH1206,SH1013)the Project of Science and Technology Department of Jiangsu Province,China(BE2011720)
文摘[Objective]The research aimed to study climatic change characteristics of sunshine hours in Lianyungang and analyze its formation reason. [Method]Based on monthly sunshine hours,precipitation,cloudiness,haze days and vapor pressure from 7 stations of Lianyungang from 1961 to 2010,monthly,seasonal,annual and interdecadal change trends of the sunshine hours were analyzed by using MK test,linear trend analysis and Morlet wavelet. Meanwhile,the cause of change characteristics was analyzed. [Result] Monthly sunshine hours of Lianyungang showed bimodal distribution,and seasonal and annual sunshine hours had decreasing trend at different degrees. The interdecadal change of sunshine hours showed wave characteristics. The annual sunshine hours had multiple temporal-spatial scale features,and there was an obvious mutation in the late 1980s. Sunshine hours in Lianyungang was closely related to visibility,cloudiness,vapor pressure and haze,and they were important factors causing that sunshine hours significantly declined. [Conclusion]The research could provide reference basis for scientifically developing and using solar energy resource and reasonably adjusting industrial and agricultural structures.
文摘Rational and accurate solar energy databases, essential for designing, sizing and performing the solar energy systems in any part of the world, are not easily accessible in different localities of Nepal. In this study, daily global solar radiation, sunshine hours and meteorological data for Biratnagar, Kathmandu, Pokhara and Jumla have been used to derive the regression constants. The linear regression technique has been used to develop a model for Biratnagar, Kathmandu, Pokhara and Jumla. The model has calculated the global solar radiation for these locations. The values of global solar radiation estimated by the model are found to be in close agreement with measured values of respective sites. The estimated values were compared with Angstrom-Prescott model and examined using the root mean square error (RMSE), mean bias error (MBE), mean percentage error (MPE), coefficient of regression (R), coefficient of determinant (R2) and correlation coefficient (CC) statistical techniques. Thus, the resultant correlations and linear regression relations may be then used for the locations of similar meteorological/geographical characteristics and also can be used to estimate the missing data of solar radiation for the respective site.
基金This work was supported in part by the Fundamental Research Funds for the Central Universities(Nos.N170303009,N180703007),China.
文摘To improve the accuracy of capacity analysis and prediction for the aircraft assembly stations,an approach for calculating the effective working hour(EWH)of automatic assembly equipment is introduced by using the dynamic mixed Weibull distribution(DMWD)model.Firstly,according to the features of aircraft assembling,a DMWD model considering the dynamic reliability of multiple subsystems and their synthetic effects on the whole equipment is established.A typical automatic drilling&riveting machine is selected as the research object,and the dynamic weights of reliability of three subsystems are modeled and solved.Subsequently the unknown parameters of the DMWD model are estimated based on maximum likelihood estimation(MLE)and Newton-Raphson method.Finally,the EWH of an automatic station is defined and modeled by using the solved dynamic reliability function.Based on the experimental study on a real automatic drilling&riveting machine from a wing panel assembly station,it is shown that the proposed DMWD and EWH models could effectively calculate the equipment reliability with full consideration of its multiple subsystems.The DMWD model is more suitable for improving the solution precision of EWH than the traditional three-parameter Weibull distribution.
文摘The present study aims to conduct 2 types of statistical analysis to reveal the impact of the spread of COVID-19 on train delays by comparing the potential contributing factors before, during and after the outbreak of the virus in the metropolitan train lines in Japan. First of all, the result of the present study clearly revealed the changes in contributing factors for train delays caused by the spread of COVID-19. Specifically, the contributing factors for train delays changed due to the decrease of passengers by the effect of the outbreak of the virus. Additionally, though large terminal stations were considered to be a major contributing factor in causing and increasing train delays in the past, this was not the case after the spread of COVID-19. Therefore, under such conditions, it is more effective to make improvements in small to medium stations and tracks rather than terminal stations. Furthermore, as the decrease in passengers also decreased train delays in commuter lines going to the suburbs due to the spread of COVID-19, the contributing factor for such lines is the excessive number of passengers. Therefore, as for countermeasures for train delays after the effects of COVID-19, it is necessary to disperse passengers in order to avoid passengers concentrating in the same time zones and train lines.
文摘The essay tries to explore the metafiction elements in Michael Cunningham’s novel The Hours.The work,The Hours,is in fact a fiction about how the fiction becomes a fiction and also a fiction about the previous fiction,Mrs.Dalloway.Through the deconstruction of the previous work,the reality and history are re-defined by The Hours.
文摘In A Room of One's Own,Virginia Woolf argued her famous proposition that a woman needed to have a room of her own to achieve literary autonomy,and laid the foundation for present-day feminist criticism.Yet the author believes that economic independent does not foster women's identity with certainty.In this thesis,the author explores the crucial place of spiritual and economic independence in building up women's autonomy through analyzing Michael Cunningham Pulitzerwinning work The Hours,which he draws inventively on the life of Virginia Woolf and her work Mrs.Dalloway.