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Study on Refined Forecast Method of Daily Maximum Temperature in Wugang City from July to September 被引量:1
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作者 LIAO Ren-guo LV Xiao-hua +2 位作者 LIU Xu-lin HE Wei-hui DAI Chuan-hong 《Meteorological and Environmental Research》 CAS 2012年第3期6-8,共3页
[Objective] The aim was to study the refined forecast method of daily highest temperature in Wugang City from July to September. IM[ethod] By dint of ECMWF mode product and T231 in 2009 and 2010 and daily maximum temp... [Objective] The aim was to study the refined forecast method of daily highest temperature in Wugang City from July to September. IM[ethod] By dint of ECMWF mode product and T231 in 2009 and 2010 and daily maximum temperature in the station in corresponding period, multi-factors similar forecast method to select forecast sample, multivariate regression multi-mode integration MOS method, after dynamic corrected mode error and regression error, dynamic forecast equation was concluded to formulate the daily maximum temperature forecast in 24 -120 h in Wugang City from July to September. [ Result] Through selection, error correction, the daily maximum temperature equation in Wugang City from July to September was concluded. Through multiple random sampling, F test was made to pass test with significant test of 0.1. [ Conclusionl The method integrated domestic and foreign forecast mode, made full use of useful information of many modes, absorbed each others advantages, con- sidered local regional environment, lessen mode and regression error, and improved forecast accuracy. 展开更多
关键词 Daily maximum temperature Multi-mode integration MOS method Dynamic forecast equatio China
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Quantification of relationship between annual daily maximum temperature and annual daily maximum rainfall in South Australia
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作者 YE Qianping AHAMMED Faisal 《Atmospheric and Oceanic Science Letters》 CSCD 2020年第4期286-293,共8页
The empirical relationship between annual daily maximum temperature(ADMT)and annual daily maximum rainfall(ADMR)was investigated.The data were collected from four weather stations located in Adelaide,South Australia,f... The empirical relationship between annual daily maximum temperature(ADMT)and annual daily maximum rainfall(ADMR)was investigated.The data were collected from four weather stations located in Adelaide,South Australia,from 1988 to 2017.Due to the influence of sea surface temperature on rainfall and temperature,the distance from the weather station to the sea was considered in the selection of weather stations.Two weather stations near the sea and two inland weather stations were selected.Three non-parametric statistical tests(Kruskal–Wallis,Mann–Whitney,and correlation)were applied to perform statistical analysis on the ADMT and ADMR data.It was revealed that the temperature and rainfall in South Australia varies according to weather station location.The distance from the sea to the weather station was found to have limited influence on temperature and rainfall.Meanwhile,with the 0.05 level of significance,the association between ADMT and ADMR near sea stations is not as significant as the association between the two inland weather stations.It is relatively unrealistic to use ADMR to predict ADMT,or vice versa,since their correlation is not statistically significant(Spearman’s rank correlation coefficient:−0.106). 展开更多
关键词 Annual daily maximum rainfall annual daily maximum temperature kruskal–Wallis Mann–Whitney correlation
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Constructal design of a rectangular porous fin considering minimization of maximum temperature difference and pumping power consumption
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作者 LIU XiaoYe FENG HuiJun +1 位作者 CHEN LinGen GE YanLin 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2024年第3期919-929,共11页
A heat dissipation model of a rectangular porous fin is established based on constructal theory. First, the constructal design of rectangular porous fin is conducted by selecting a complex function minimization, which... A heat dissipation model of a rectangular porous fin is established based on constructal theory. First, the constructal design of rectangular porous fin is conducted by selecting a complex function minimization, which composed of linear weighting sum of maximum temperature difference and pumping power consumption, as optimization objective. Effects of gap height, air inlet velocity, total porous fin volume and porosity on the optimal constructs are investigated, respectively. The findings show that the complex function can attain its double minimum at a value of 0.802 when the fin length and number are optimized, and the corresponding optimal fin length and number are 8.01 mm and 10, respectively. In comparison to original design, the complex function and maximum temperature difference after twice optimization are decreased by 19.80% and 66.31%, respectively.Second, the comprehensive performance of porous fin is improved by simultaneously optimizing the fin length and number. The artificial neural network is applied to predict the fin performances, which is used to conduct multi-objective optimization based on NSGA-II algorithm. Optimal structure of porous fin for multiple requirements is gained by LINMAP and TOPSIS decisionmaking strategies. The findings in this study can serve as theoretical guides for fin thermal designs of electronic devices. 展开更多
关键词 constructal theory rectangular porous fin pumping power consumption maximum temperature difference complex function multi-objective optimization
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Application of Machine-Learning-Based Objective Correction Method in the Intelligent Grid Maximum and Minimum Temperature Predictions
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作者 Jing Liu Chuan Ren +2 位作者 Ningle Yuan Shuai Zhang Yue Wang 《Atmospheric and Climate Sciences》 2023年第4期507-525,共19页
Post-processing correction is an effective way to improve the model forecasting result. Especially, the machine learning methods have played increasingly important roles in recent years. Taking the meteorological obse... Post-processing correction is an effective way to improve the model forecasting result. Especially, the machine learning methods have played increasingly important roles in recent years. Taking the meteorological observational data in a period of two years as the reference, the maximum and minimum temperature predictions of Shenyang station from the European Center for Medium-Range Weather Forecasts (ECMWF) and national intelligent grid forecasts are objectively corrected by using wavelet analysis, sliding training and other technologies. The evaluation results show that the sliding training time window of the maximum temperature is smaller than that of the minimum temperature, and their difference is the largest in August, with a difference of 2.6 days. The objective correction product of maximum temperature shows a good performance in spring, while that of minimum temperature performs well throughout the whole year, with an accuracy improvement of 97% to 186%. The correction effect in the central plains is better than in the regions with complex terrain. As for the national intelligent grid forecasts, the objective correction products have shown positive skills in predicting the maximum temperatures in spring (the skill-score reaches 0.59) and in predicting the minimum temperature at most times of the year (the skill-score reaches 0.68). 展开更多
关键词 Machine Learning Sliding Training Forecast Correction maximum and Minimum temperature
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Changes in Extreme Maximum Temperature Events and Population Exposure in China under Global Warming Scenarios of 1.5 and 2.0°C: Analysis Using the Regional Climate Model COSMO-CLM 被引量:11
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作者 Mingjin ZHAN Xiucang LI +3 位作者 Hemin SUN Jianqing ZHAI Tong JIANG Yanjun WANG 《Journal of Meteorological Research》 SCIE CSCD 2018年第1期99-112,共14页
We used daily maximum temperature data(1986–2100) from the COSMO-CLM(COnsortium for Small-scale MOdeling in CLimate Mode) regional climate model and the population statistics for China in 2010 to determine the fr... We used daily maximum temperature data(1986–2100) from the COSMO-CLM(COnsortium for Small-scale MOdeling in CLimate Mode) regional climate model and the population statistics for China in 2010 to determine the frequency, intensity, coverage, and population exposure of extreme maximum temperature events(EMTEs) with the intensity–area–duration method. Between 1986 and 2005(reference period), the frequency, intensity, and coverage of EMTEs are 1330–1680 times yr^–1, 31.4–33.3℃, and 1.76–3.88 million km^2, respectively. The center of the most severe EMTEs is located in central China and 179.5–392.8 million people are exposed to EMTEs annually. Relative to 1986–2005, the frequency, intensity, and coverage of EMTEs increase by 1.13–6.84, 0.32–1.50, and15.98%–30.68%, respectively, under 1.5℃ warming; under 2.0℃ warming, the increases are 1.73–12.48, 0.64–2.76,and 31.96%–50.00%, respectively. It is possible that both the intensity and coverage of future EMTEs could exceed the most severe EMTEs currently observed. Two new centers of EMTEs are projected to develop under 1.5℃ warming, one in North China and the other in Southwest China. Under 2.0℃ warming, a fourth EMTE center is projected to develop in Northwest China. Under 1.5 and 2.0℃ warming, population exposure is projected to increase by 23.2%–39.2% and 26.6%–48%, respectively. From a regional perspective, population exposure is expected to increase most rapidly in Southwest China. A greater proportion of the population in North, Northeast, and Northwest China will be exposed to EMTEs under 2.0℃ warming. The results show that a warming world will lead to increases in the intensity, frequency, and coverage of EMTEs. Warming of 2.0℃ will lead to both more severe EMTEs and the exposure of more people to EMTEs. Given the probability of the increased occurrence of more severe EMTEs than in the past, it is vitally important to China that the global temperature increase is limited within 1.5℃. 展开更多
关键词 extreme maximum temperature events population exposure 1.5 and 2.0℃ global warming COSMO-CLM regional climate model China
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Analysis of Sampling Error Uncertainties and Trends in Maximum and Minimum Temperatures in China 被引量:2
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作者 HUA Wei Samuel S.P.SHEN WANG Huijun 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2014年第2期263-272,共10页
In this paper we report an analysis of sampling error uncertainties in mean maximum and minimum temperatures (Tmax and Tmin) carried out on monthly,seasonal and annual scales,including an examination of homogenized ... In this paper we report an analysis of sampling error uncertainties in mean maximum and minimum temperatures (Tmax and Tmin) carried out on monthly,seasonal and annual scales,including an examination of homogenized and original data collected at 731 meteorological stations across China for the period 1951-2004.Uncertainties of the gridded data and national average,linear trends and their uncertainties,as well as the homogenization effect on uncertainties are assessed.It is shown that the sampling error variances of homogenized Tmax and Tmin,which are larger in winter than in summer,have a marked northwest-southeast gradient distribution,while the sampling error variances of the original data are found to be larger and irregular.Tmax and Tmin increase in all months of the year in the study period 1951-2004,with the largest warming and uncertainties being 0.400℃ (10 yr)-1 + 0.269℃ (10 yr)-1 and 0.578℃ (10 yr)-1 + 0.211℃ (10 yr)-1 in February,and the least being 0.022℃ (10 yr)-1 + 0.085℃ (10 yr)-1 and 0.104℃ (10 yr)-1 +0.070℃ (10 yr)-1 in August.Homogenization can remove large uncertainties in the original records resulting from various non-natural changes in China. 展开更多
关键词 sampling error uncertainty maximum temperature minimum temperature temperature trend
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Numerical and experimental study on the critical velocity and smoke maximum temperature in the connected area of branch tunnel 被引量:1
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作者 Haihang Li Fei Tang 《Building Simulation》 SCIE EI CSCD 2022年第4期525-536,共12页
The objective of this study is to investigate critical velocity and smoke maximum temperature beneath the ceiling in the connected area of branch tunnel with varying fire locations.The fire sources were located in the... The objective of this study is to investigate critical velocity and smoke maximum temperature beneath the ceiling in the connected area of branch tunnel with varying fire locations.The fire sources were located in the divergent connected area of the branch tunnel,to imitate traffic accidents near the branch point.A 1/20 scale model branch tunnel was built including main line before branch,main line after branch,and ramp.Experimental tests and numerical simulations were performed to explore smoke movement characteristics with longitudinal ventilation.The results showed that the enlarged cross-sectional area in branch tunnel caused the shortening of the back-layering length,and a modified model of back-layering length was proposed.The higher tunnel height in this work affected the critical condition of large fire;it caused a larger transition point of dimensionless critical velocity.A revised model was proposed for the maximum temperature rise of tunnel fires in the connected area of branch tunnel.The critical velocity kept unchanged when the branch angle increased from 0°to 20°because there is little change in the longitudinal smoke temperature.As the local tunnel width of fire source was increased,the required critical velocity was increased while the local effective velocity kept nearly the same. 展开更多
关键词 tunnel fire critical velocity maximum temperature dimensionless back-layering length branch tunnel
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Asymmetrical Change Characteristics of Maximum and Minimum Temperatures in Shangqiu in Recent 50 Years
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作者 ZHANG Yun-xia Shangqiu Meteorological Bureau in Henan Province,Shangqiu 476000,China 《Meteorological and Environmental Research》 CAS 2011年第10期50-54,58,共6页
[Objective] The research aimed to analyze temporal and spatial variation characteristics of temperature in Shangqiu City during 1961-2010.[Method] Based on temperature data in eight meteorological stations of Shangqiu... [Objective] The research aimed to analyze temporal and spatial variation characteristics of temperature in Shangqiu City during 1961-2010.[Method] Based on temperature data in eight meteorological stations of Shangqiu during 1961-2010,by using trend analysis method,the temporal and spatial evolution characteristics of annual average temperature,annual average maximum and minimum temperatures,annual extreme maximum and minimum temperatures,daily range of annual average temperature in Shangqiu City were analyzed.M-K method was used to determine mutation year of temperature.[Result] The annual average temperature,annual average minimum temperature and annual extreme minimum temperature respectively rose at 0.122,0.255 and 0.488 ℃/10 a.The variation trend of annual average maximum temperature wasn’t obvious.The daily range of annual average temperature and annual extreme maximum temperature respectively declined at-0.217 and-0.292 ℃/10 a.Seen from spatial distribution,the increase amplitudes of annual average temperature,annual average minimum temperature and annual extreme minimum temperature were all large in the east and small in the west.The decrease amplitude of daily range of annual average temperature was large in the east and small in the west.The decrease amplitude of annual extreme maximum temperature was large in the west and small in the east.The annual average maximum temperature had trends of increase and decrease.The annual average temperature,annual average minimum temperature and daily range of annual average temperature all mutated in 1997.The annual average maximum temperature didn’t have obvious mutation point.The annual extreme maximum temperature mutated in 1973.The annual extreme minimum temperature respectively mutated in 1989 and 1999.[Conclusion] The research played important guidance significances in adjustment of agricultural production structure,regional climate planning,reasonably using climate resource and replying climate change in Shangqiu City. 展开更多
关键词 Average temperature maximum and minimum temperatures Extreme temperature Daily range Climate change Temporal and spatial variation characteristics China
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Climatic characteristics of high temperature in East China during 1961-2005 被引量:5
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作者 SHI Jun TANG Xu CUI Linli 《Journal of Geographical Sciences》 SCIE CSCD 2008年第3期283-294,共12页
Based on the daily maximum temperature data covering the period 1961-2005, temporal and spatial characteristics and their changing in mean annual and monthly high temperature days(HTDs)and the mean daily maximum tem... Based on the daily maximum temperature data covering the period 1961-2005, temporal and spatial characteristics and their changing in mean annual and monthly high temperature days(HTDs)and the mean daily maximum temperature(MDMT)during annual and monthly HTDs in East China were studied.The results show that the mean annual HTDs were 15.1 and the MDMT during annual HTDs was 36.3℃in the past 45 years.Both the mean annual HTDs and the MDMT during annual HTDs were negative anomaly in the1980s and positive anomaly in the other periods of time,oscillating with a cycle of about 12-15 years.The mean annual HTDs were more in the southern part,but less in the northern part of East China.The MDMT during annual HTDs was higher in Zhejiang,Anhui and Jiangxi provinces in the central and western parts of East China.The high temperature process(HTP) was more in the southwestern part,but less in northeastern part of East China.Both the HTDs and the numbers of HTP were at most in July,and the MDMT during monthly HTDs was also the highest in July.In the first 5 years of the 21st century,the mean annual HTDs and the MDMT during annual HTDs increased at most of the stations,both the mean monthly HTDs and the MDMT during monthly HTDs were positive anomalies from April to October,the number of each type of HTP generally was at most and the MDMT in each type of HTP was also the highest. 展开更多
关键词 climatic characteristics high temperature days (HTDs) mean daily maximum temperature (MDMT) during HTDs high temperature process (HTP) East China
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The Short-term Effects of Temperature on Infectious Diarrhea among Children under 5 Years Old in Jiangsu,China:A Time-series Study(2015-2019) 被引量:3
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作者 Nan-nan HUANG Hao ZHENG +4 位作者 Bin LI Gao-qiang FEI Zhen DING Jia-jia WANG Xiao-bo LI 《Current Medical Science》 SCIE CAS 2021年第2期211-218,共8页
The association between meteorological factors and infectious diarrhea has been widely studied in many countries.However,investigation among children under 5 years old in Jiangsu,China remains quite limited.Data inclu... The association between meteorological factors and infectious diarrhea has been widely studied in many countries.However,investigation among children under 5 years old in Jiangsu,China remains quite limited.Data including infectious diarrhea cases among children under five years old and daily meteorological indexes in Jiangsu,China from 2015 to 2019 were collected.The lag-effects up to 21 days of daily maximum temperature(Tmax)on infectious diarrhea were explored using a quasi-Poisson regression with a distributed lag non-linear model(DLNM)approach.The cases number of infectious diarrhea was significantly associated with seasonal variation of meteorological factors,and the burden of disease mainly occurred among children aged 0-2 years old.Moreover,when the reference value was set at 16.7°C,Tmax had a significant lag-effect on cases of infectious diarrhea among children under 5 years old in Jiangsu Province,which was increased remarkably in cold weather with the highest risk at 8℃.The results of DLNM analysis implicated that the lag-effect of Tmax varied among the 13 cities in Jiangsu and had significant differences in 8 cities.The highest risk of Tmax was presented at 5 lag days in Huaian with a maximum RR of 1.18(95% CI:1.09,1.29).Suzhou which had the highest number of diarrhea cases(15830 cases),had a maximum RR of 1.04(95%CI:1.03,1.05)on lag 15 days.Tmax is a considerable indicator to predict the epidemic of infectious diarrhea among 13 cities in Jiangsu,which reminds us that in cold seasons,more preventive strategies and measures should be done to prevent infectious diarrhea. 展开更多
关键词 infectious diarrhea INCIDENCE meteorological factors maximum temperature(Tmax) lag-effect
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Temperature Field Analysis of Mine Flameproof Outer Rotor Permanent Magnet Synchronous Motor with Different Cooling Schemes 被引量:1
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作者 Shengnan Wu Daquan Hao Wenming Tong 《CES Transactions on Electrical Machines and Systems》 CSCD 2022年第2期162-169,共8页
Aiming at the problem of temperature rise of mine flameproof outer rotor permanent magnet synchronous motor,based on the fluid structure coupling method,the temperature distribution of motor under three cooling scheme... Aiming at the problem of temperature rise of mine flameproof outer rotor permanent magnet synchronous motor,based on the fluid structure coupling method,the temperature distribution of motor under three cooling schemes of air cooling and water cooling are calculated respectively.For the structure I air cooling system,the influence of different number of heat sink on the maximum temperature rise and pressure drop of fluid channel is analyzed,and the parameters of heat sink are optimized.For the structure II air cooling system,the influence of setting fillet at the turn back of the fluid channel on the head loss in the fluid domain of the motor is analyzed,and the influence of different fillet radius on the head loss and the maximum temperature rise in the fluid domain is obtained.For the structure II water cooling system,the influence of different water flow speed on the maximum temperature rise of the motor is analyzed,and the influence of different assembly clearance of modular stator teeth and yoke on the maximum temperature rise of the motor is analyzed.The cooling effect and temperature rise distribution characteristics of the three cooling schemes are compared and analyzed.Finally,a water-cooled prototype is manufactured,and the temperature rise experiment is carried out,and the influence of the thermal deformation of fluid channel,stator yoke and stator teeth on the maximum temperature of the motor is analyzed.The results show that the calculated temperature field after considering the thermal deformation is closer to the experimental value,which verifies the accuracy of the calculation results,It also provides a reference for the selection and design of the cooling structure of the same type of PMSM electric roller. 展开更多
关键词 Permanent magnet synchronous motor with outer rotor Fluid structure coupling maximum temperature rise and head loss Assembly clearance and thermal deformation
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The Relation among Synthetic Fluid Inclusions Homogenization Temperature of Halite,Air Temperature and Water Temperature under Natural Conditions
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作者 QIN Huan CHI Zhe +3 位作者 ZHOU hua SUN Xiaochi MENG Fanwei PEI Ni 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期244-244,共1页
A large number of fluid inclusions are formed in the crystal formation of halite,in which pure liquid phase ones supply a new method of paleo temperature inversion by means of cryogenic thermometry.In this study,we
关键词 halite fluid inclusions homogenization temperature air temperature maximum temperature
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Variation Characteristics of Winter Temperature in Jinan in Recent 60 Years
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作者 ZHANG Li Department of Policies and Statutes,Shandong Meteorological Bureau,Jinan 250013,China 《Meteorological and Environmental Research》 CAS 2011年第7期9-11,共3页
[Objective] The research aimed to study the variation characteristics of winter temperature in Jinan in recent 60 years.[Method] Based on winter monthly average,maximum and minimum temperatures in the ground observati... [Objective] The research aimed to study the variation characteristics of winter temperature in Jinan in recent 60 years.[Method] Based on winter monthly average,maximum and minimum temperatures in the ground observation station of Jinan during 1951-2010,by using linear trend,5-year moving average and anomaly,the variation characteristics of winter average,maximum and minimum temperatures in Jinan in recent 60 years were analyzed.The historical evolution trend and decadal variation characteristics were discussed.[Result] Winter average,maximum and minimum temperatures in Jinan in recent 60 years all presented slow fluctuation rise trend.The rise trend was obvious.Especially the increase amplitude of minimum temperature was the maximum.It illustrated that the variation of minimum temperature was more sensitive than that of maximum temperature,and the climatic warming in winter was mainly from the contribution of minimum temperature rise.Seen from the decadal variation,cold winter mainly appeared before the 1970s.Then,it presented obvious decrease trend.Conversely,warm winter presented increase trend after the 1970s.Warm winter phenomenon slowed after 2000.Winter temperature presented stepped warming trend during 1950s-1990s.Winter average temperature presented jumped warming trend when entered into the 1990s.The temperature presented downward trend when entered into the 21st century.But winter temperature still presented rise trend as a whole.The population growth in Jinan made that urbanization process accelerated,and urban heat island effect aggravated.It was one of important factors for climate warming in Jinan.[Conclusion] The research provided theoretical basis for understanding the long-term variation trend of climate in Jinan area,and if it was consistent with the background of global climatic warming. 展开更多
关键词 Winter temperature maximum temperature Minimum temperature Variation characteristic China
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Summer water temperature structures and their interannual variation in the upper Canada Basin 被引量:4
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作者 ZHAO Jinping CAO Yong 《Advances in Polar Science》 2011年第4期223-234,共12页
Conductivity, temperature and depth (CTD) data from 1993 2010 are used to study water tempera- ture in the upper Canada Basin. There are four kinds of water temperature structures: The remains of the winter convect... Conductivity, temperature and depth (CTD) data from 1993 2010 are used to study water tempera- ture in the upper Canada Basin. There are four kinds of water temperature structures: The remains of the winter convective mixed layer, the near-surface temperature maximum (NSTM), the wind-driven mixed layer, and the advected water under sea ice. The NSTM mainly appears within the conductive mixed layer that forms in winter. Solar heating and surface cooling are two basic factors in the formation of the NSTM. The NSTM can also appear in undisturbed open water, as long as there is surface cooling. Water in open water areas may advect beneath the sea ice. The overlying sea ice cools the surface of the advected water, and a temperature maximum could appear similar to the NSTM. The NSTM mostly occurred at depths 10-30 m because of its deepening and strengthening during smnmer, with highest frequency at 20 m. Two clear stages of interannual variation are identified. Before 2003, most NSTMs were observed in marginal ice zones and open waters, so temperature maxima were usually warmer than 0~C. After 2004, most NSTMs occurred in ice-covered areas, with nmch colder temperature maxima. Average depths of the temperature maxima in most years were about 20 m, except for about 16 m in 2007, which was related to the extreme minimum of ice cover. Average temperatures were around 0.8~C to 1.1~C, but increased to around 0.5~C in 2004, 2007 and 2009, corresponding to reduced sea ice. As a no-ice summer in the Arctic is expected, the NSTM will be warmer with sea ice decline. Most energy absorbed by seawater has been transported to sea ice and the atmosphere. The heat near the NSTM is only the remains of total absorption, and the energy stored in the NSTM is not considerable. However, the NSTM is an important sign of the increasing absorption of solar energy in seawater. 展开更多
关键词 Canada Basin upper ocean near-surface temperature maximum HALOCLINE WARMING
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Conceptual design and safety characteristics of a new multi-mission high flux research reactor 被引量:1
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作者 Wei Xu Jian Li +4 位作者 Heng Xie Zhi-Hong Liu Jing Zhao Fei Xie Lei Shi 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第3期9-24,共16页
Research reactors with neutron fluxes higher than 10^(14) n cm^(−2) s^(−1) are widely used in nuclear fuel and material irradiation,neutron-based scientific research,and medical and industrial isotope production.Such ... Research reactors with neutron fluxes higher than 10^(14) n cm^(−2) s^(−1) are widely used in nuclear fuel and material irradiation,neutron-based scientific research,and medical and industrial isotope production.Such high flux research reactors are not only important scientific research facilities for the development of nuclear energy but also represent the national comprehensive technical capability.China has several high flux research reactors that do not satisfy the requirements of nuclear energy development.A high flux research reactor has the following features:a compact core arrangement,high power density,plate-type fuel elements,a short refueling cycle,and high coolant velocity in the core.These characteristics make it difficult to simultaneously realize high neutron flux and optimal safety margin.A new multi-mission high flux research reactor was designed by the Institute of Nuclear and New Energy Technology at Tsinghua University in China;the reactor can simul-taneously realize an average neutron flux higher than 2.0×10^(15) n cm^(−2) s^(−1) and fulfill the current safety criterion.This high flux research reactor features advanced design concepts and has sufficient safety margins according to the preliminary safety analysis.Based on the analysis of the station blackout accident,loss of coolant accident,and reactivity accident of a single-control drum rotating out accidently,the maximum temperature of the cladding surface,minimum departure from nucleate boiling ratio,and temperature difference to the onset of nucleate boiling temperature satisfy the design limits. 展开更多
关键词 High flux research reactor Neutron flux Safety analysis maximum temperature of cladding surface Departure from nucleate boiling ratio
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The Influence of Climate Variability on the Watermelon Production in Zanzibar
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作者 Asya Omar Hamad Kombo Hamad Kai +5 位作者 Agnes Kijazi Sara Abdalla Khamis Abdalla Hassan Abdalla Hassan Khatib Ame Masoud Makame Faki Faki Ali Ali 《Atmospheric and Climate Sciences》 CAS 2023年第1期44-61,共18页
Climate change and variability, has embarked societies in Zanzibar to rely on horticulture (i.e. watermelon production) as an adaptive measure due to an unpromising situation of commonly used agricultural yields. Curr... Climate change and variability, has embarked societies in Zanzibar to rely on horticulture (i.e. watermelon production) as an adaptive measure due to an unpromising situation of commonly used agricultural yields. Currently, there is either no or scant information that describes the influence of climate changes and variability to watermelon production in Zanzibar. Thus, this study aimed to determine the influence of climate variability on the quantity of watermelon production in Zanzibar. The study used both primary and secondary datasets, which include the anecdotal information collected from interviewers’ responses from four districts of Unguja and Pemba, and climate parameters (rainfall, maximum and minimum temperature (Tmax and Tmin) acquired from Tanzania Meteorological Authority (TMA) at Zanzibar offices. Pearson correlation was used for analyzing the association between watermelon production and climate parameters, while paired t-test was applied to show the significance of the mean differences of watermelon and climate parameters for two periods of 2014-2017 and 2018-2021, respectively. Percentage changes were used to feature the extent to which the two investigated parameters affect each other. The anecdotal responses were sorted, calculated in monthly and seasonal averages, plotted and then analyzed. Results have shown a strong correlation (r = 0.8 at p ≤ 0.02, and r = 0.7) between watermelon production, Tmax and rainfall during OND, especially in Unguja, as well as Tmin during JJA (i.e. r = - 0.8 at p ≤ 0.02) in Pemba. Besides, results have shown the existence of significant differences between the means of watermelon production and climate parameter for the two stated periods, indicating that the climate parameters highly affects the watermelon production by either enhancing or declining the yields by 69% - 162% and 17% - 77%, respectively. Moreover, results have shown that respondents were aware that excess temperature intensity during dry periods can lead to high production costs due number of soil and other environmental factors. Besides the results have shown that OND seasonal rainfall and MAM Tmax had good association with watermelon production in Unguja while JJA Tmin declined the production in Pemba. Thus, the study concludes that seasonal variability of climate parameter has a significant influence on the watermelon production. The study calls for more studies on factors affecting watermelon production (e.g. soil characteristics, pest sides and manure), and recommends for climate based decision making on rain fed agricultural yields and routine monitoring of weather information. 展开更多
关键词 WATERMELON March to May (MAM) and October to November (OND) Seasonal Rainfall maximum and Minimum temperature Anecdotal Information
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基于REOF研究辽宁省极端最高气温时空分布(英文) 被引量:2
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作者 王震 王颖 《Meteorological and Environmental Research》 CAS 2010年第11期1-3,8,共4页
By selecting the daily maximum temperatures during 1961-2005 in 35 representative stations in Liaoning Province, the temporal and spatial distribution characteristics of extremely maximum temperature event were studie... By selecting the daily maximum temperatures during 1961-2005 in 35 representative stations in Liaoning Province, the temporal and spatial distribution characteristics of extremely maximum temperature event were studied. By using REOF, the mean-square deviation and so on, the variation and distribution situation of extremely maximum temperature in the different regions of Liaoning were reflected. The results showed that the extremely maximum temperature in Liaoning Province could be divided into 3 regions where were respectively the northeast area, the west and the northwest area, the south and the southeast area. The distribution characteristic of extremely maximum temperature threshold value in Liaoning Province was basically consistent with the distribution characteristic of average temperature. The zone where the extremely maximum temperature threshold was relatively high was in the northwest area of Liaoning, and the low threshold zone was in the southeast area and most areas in the east. The variation of extremely maximum temperature in winter was the greatest and in summer was the smallest. The variation of extremely maximum temperature days was the greatest in summer and wasn't great in spring, autumn, winter. 展开更多
关键词 Extremely maximum temperature Spatial and temporal distribution REOF analysis China
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ON CHANGES OF CHINA'S MAXIMUM AND MINIMUM TEMPERATURES IN 1951——1990 被引量:3
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作者 翟盘茂 任福民 《Acta meteorologica Sinica》 SCIE 1999年第3期278-290,共13页
Based on China's observational data in 1951-1990,after minimizing the possible biases caused by station relocation and urban heat island,the spatial and temporal distributions of trends for maximum and minimum tem... Based on China's observational data in 1951-1990,after minimizing the possible biases caused by station relocation and urban heat island,the spatial and temporal distributions of trends for maximum and minimum temperatures are studied.The results show that increasing trends of maximum temperatures are in the areas west to 95°E,and north to the Huanghe(Yellow)River, while decreasing trends exist in eastern China south to the Yellow River.Minimum temperatures are generally increasing throughout China,with dominant warming trends at the higher latitudes. This resulted in very obvious decreasing trends in diurnal temperature ranges. The periodic cycles are consistent between the maximum and minimum temperatures,but asymmetric trends are very obvious.The significant increase of minimum(nighttime)temperatures reflects the evidence of enhancement of greenhouse effect.Further analysis shows that the changes of maximum and minimum temperatures are mainly related to sunshine duration and atmospheric water vapor content. 展开更多
关键词 maximum temperatures minimum temperatures CHANGE
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Correlation Analysis of Rice Seed Setting Rate and Weight of 1 000-Grain and Agro-Meteorology over the Middle and Lower Reaches of the Yangtze River,China 被引量:2
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作者 ZHAO Hai-yan YAO Feng-mei +4 位作者 ZHANG Yong XU Bin YUAN Jing HU Ya-nan XU Yin-long 《Agricultural Sciences in China》 CAS CSCD 2007年第4期430-436,共7页
The purpose of this study is to reveal the effects of historic climate change on rice yield over the middle and lower reaches of the Yangtze River, China, and to better adapt to climate change in the future. This stud... The purpose of this study is to reveal the effects of historic climate change on rice yield over the middle and lower reaches of the Yangtze River, China, and to better adapt to climate change in the future. This study presents the relation of temperature and precipitation and rice components from 1981 to 2003 at 48 early rice stations and 30 middle rice stations. It focuses on an analysis of three stages: flowering, pre-milk, and late milk. The results show that mean maximum temperature and mean daily precipitation at the stages of flowering and pre-milk are most related to early rice yield. Yield change of middle rice is mainly because of mean precipitation change at the flowering stage. Furthermore, percentage of undeveloped grain increases as mean maximum temperature rises at the flowering stage. Over-precipitation in the reproductive stage is a major reason for reduction in yield of early rice. Consecutive rainfall and continuous high temperature can have negative effects on middle rice yield. Global warming would affect middle rice more seriously than early rice. 展开更多
关键词 mean maximum temperature mean daily precipitation percentage of undeveloped grain percentage of partially developed grain weight of 1 000-grain
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Cooling System Design and Thermal Analysis of Modular Stator Hybrid Excitation Synchronous Motor
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作者 Shengnan Wu Daquan Hao Wenming Tong 《CES Transactions on Electrical Machines and Systems》 CSCD 2022年第3期241-251,共11页
Hybrid excitation synchronous motor has the advantages of uniform and adjustable electromagnetic field, wide speed range and high power density. It has broad application prospects in new energy electric vehicles, wind... Hybrid excitation synchronous motor has the advantages of uniform and adjustable electromagnetic field, wide speed range and high power density. It has broad application prospects in new energy electric vehicles, wind power generation and other fields. This paper introduces the basic structure of hybrid excitation motor with modular stator, and analyzes the operation principle of hybrid excitation motor. The cooling structure of the water-cooled plate is designed, and the effects of the thickness of the water-cooled plate and the number of water channels in the water-cooled plate on the heat dissipation capacity of the water-cooled plate are analyzed by theoretical and computational fluid dynamics methods. The effects of different water cooling plate structures on water velocity, pressure drop, water pump power consumption and heat dissipation capacity were compared and analyzed. The influence of different inlet flow velocity on the maximum temperature rise of each part of the motor is analyzed, and the temperature of each part of the motor under the optimal water flow is analyzed. The influence of the traditional spiral water jacket cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of the motor components is compared and analyzed. The results show that the water-cooled plate cooling structure is more suitable for the modular stator motor studied in this paper. Based on the water-cooled plate cooling structure, the air-water composite cooling structure is designed, and the effects of the air-water composite cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of each component of the motor are compared and analyzed. The results show that the maximum temperature rise of each component of the motor is reduced under the air-water composite cooling structure. 展开更多
关键词 Hybrid excitation synchronous motor Cooling structure of the water-cooled plate The heat dissipation capacity of the water-cooled plate The maximum temperature rise of each part Air water composite cooling structure
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