Traffic flow prediction is an important part of the intelligent transportation system. Accurate multi-step traffic flow prediction plays an important role in improving the operational efficiency of the traffic network...Traffic flow prediction is an important part of the intelligent transportation system. Accurate multi-step traffic flow prediction plays an important role in improving the operational efficiency of the traffic network. Since traffic flow data has complex spatio-temporal correlation and non-linearity, existing prediction methods are mainly accomplished through a combination of a Graph Convolutional Network (GCN) and a recurrent neural network. The combination strategy has an excellent performance in traffic prediction tasks. However, multi-step prediction error accumulates with the predicted step size. Some scholars use multiple sampling sequences to achieve more accurate prediction results. But it requires high hardware conditions and multiplied training time. Considering the spatiotemporal correlation of traffic flow and influence of external factors, we propose an Attention Based Spatio-Temporal Graph Convolutional Network considering External Factors (ABSTGCN-EF) for multi-step traffic flow prediction. This model models the traffic flow as diffusion on a digraph and extracts the spatial characteristics of traffic flow through GCN. We add meaningful time-slots attention to the encoder-decoder to form an Attention Encoder Network (AEN) to handle temporal correlation. The attention vector is used as a competitive choice to draw the correlation between predicted states and historical states. We considered the impact of three external factors (daytime, weekdays, and traffic accident markers) on the traffic flow prediction tasks. Experiments on two public data sets show that it makes sense to consider external factors. The prediction performance of our ABSTGCN-EF model achieves 7.2%–8.7% higher than the state-of-the-art baselines.展开更多
It is well known that English is the world language nowadays, and it is an official language in most countries. It is also currently the language most often taught as a foreign language. The reasons of the popularity ...It is well known that English is the world language nowadays, and it is an official language in most countries. It is also currently the language most often taught as a foreign language. The reasons of the popularity lie in both internal factors and external factors. In this paper, the author will analyze the factors that help to push English into a popular world language.展开更多
This case study on one Chinese EFL learner examined both the internal and external factors that affect Chinese EFL learner's speaking performance. Three interviews and three tests have been conducted in the whole ...This case study on one Chinese EFL learner examined both the internal and external factors that affect Chinese EFL learner's speaking performance. Three interviews and three tests have been conducted in the whole process, and the findings revealed:(1) interference from first language is the most influential factor that hinders speaking performance;(2) learner attitude significantly affects speaking performance;(3) learning strategies and practicing help improving performance.展开更多
Sperm motility is important in reproductive biology. To understand the physiological ecology characteristics of sperm of Sepiella maindroni, we studied the activation rate, active time, and lifespan of sperm to evalua...Sperm motility is important in reproductive biology. To understand the physiological ecology characteristics of sperm of Sepiella maindroni, we studied the activation rate, active time, and lifespan of sperm to evaluate the influence of external factors, including temperature, salinity, pH, glucose, NaCl, KCl, MgCl2, CaCl2, EDTA-2Na and artificial seawater on sperm motility. The results show that the appropriate activation and motility condition for sperm were： temperature 20-30℃ （optimum 25℃）, salinity 10.6-30.6 （optimum 15.9） and pH 8.0-8.6 （optimum 8.0-8.4）. Sperm activity varied in different concentrations of glucose, NaCl, KCl, MgCl2 and CaCl〉 None of the selected concentrations of EDTA-2Na solution could activate the sperm. The activation rate in artificial seawater devoid of Ca2＋, Mg2＋ or HCO3- was low. The results should help further studies on the preservation and activation of squid sperm.展开更多
Analysis of the problem of predicting bankruptcy shows that foreign and domestic models included only internal factors of enterprises. But the same indicators of internal factors in the rapidly changing external envir...Analysis of the problem of predicting bankruptcy shows that foreign and domestic models included only internal factors of enterprises. But the same indicators of internal factors in the rapidly changing external environment can lead to bankruptcy, and not in others. External factors are the most dangerous, because the possible influence on them is minimal and the impact of their implementation can be devastating. This paper focuses on the same factors to assess the impact of the macroeconomic indicators （extemal factors） on the parameters of static models predicting a local approximation of the crisis at the plant. To accomplish the purpose, a Spark set of 100 companies was compiled, including 50 companies which officially declared bankruptcy in the period of 2000-2009 and 50 stable operating companies with a random sample of the same time period. External factors were extracted from the Joint Economic and Social Data Archive1 The author compared two data sets： （1） microeconomic indicators--money to the total liabilities, retained earnings to total assets, net profit to revenue, Earnings Before Interest and Taxes （EBIT） to assets, net income to equity, net profit to total liabilities, current liabilities to total assets, the totality of short-term and long-term loans to total assets, current assets to current liabilities, assets to revenue, equity to total assets, and current assets to revenue; and （2） external factors--index of real gross domestic product （GDP）, industrial production index, the index of real cash incomes, an index of real investments, consumer price index, the refinancing rate, unemployment rate, the price of electricity, gas prices, oil price, gas price, dollar to ruble, ruble euro Standard ＆ Poor （S＆P） index, the Russian Trading System （RTS） index, and region. The aim of the comparison results paging classes ＂insolvent＂ and ＂non-bankrupt＂ is achieved using two methods： classification and discrimination. In both methods, computational procedures are realized with the use of algorithms linear regression, artificial neural network, and genetic algorithm. In the 2-m model, data set includes both internal and external factors. The results showed that the inclusion of only the microeconomic indicators, excluding external factors, impedes models about two times.展开更多
The relationship between assessment and learning has gradually become a widely discussed topic in the field of education. The effective implementation of the assessment has a positive impact on promoting learning. Thi...The relationship between assessment and learning has gradually become a widely discussed topic in the field of education. The effective implementation of the assessment has a positive impact on promoting learning. This research is to collect learners' feedback on the related issues of process evaluation through questionnaires and analyze the data, explore the external influencing factors and causes of the effect of process evaluation, in order to correct some cognitive biases, avoid mistakes in the evaluation process, optimize the design of classroom evaluation activities, and improve the specific evaluation steps. The results of data analysis confirm that mutual evaluation and self-evaluation are the main influencing factors of process evaluation. Other external factors, such as whether teachers demonstrate the use of gauges, whether timely feedback is given, whether guidance is given to evaluation activities, and the number of evaluation components, all have an impact on the evaluation results. If teachers make use of the above factors locally, it will have a positive impact on the evaluation effect, otherwise, it will have a negative impact on the evaluation effect.展开更多
With the continuous growth of the scale of China's foreign direct investment, more and more domestic enterprises begin to choose "going out", which not only expands the international influence of the ent...With the continuous growth of the scale of China's foreign direct investment, more and more domestic enterprises begin to choose "going out", which not only expands the international influence of the enterprises themselves, but also makes an important contribution to China's economic development. With the implementation of the national "go globally" strategy, industrial gas enterprises can also expand their market. Different from inward investment, outward investment has its special complexity and uncertainty, so it is very important to explore its influencing factors. However, the external investment of industrial gas is influenced by both the external environment and the risks of gas supply customers. In this paper, the influence of the uncertainty of the main external factors on the foreign direct investment of gas enterprises is briefly described.展开更多
For many years, scholars have been studying the factors that influence foreign language learning. Generally speaking,the factors that influence foreign language learning can be divided into internal and external facto...For many years, scholars have been studying the factors that influence foreign language learning. Generally speaking,the factors that influence foreign language learning can be divided into internal and external factors. Whether internal or external factors, they are interconnected in playing their different roles in learners' process of acquiring a foreign language. Internal factors are things like learners' age, intelligence, language aptitude, attitude, personality, etc while design of curriculum, teachers' instruction, the status of target language culture, and access to native speakers can be categorized into external factors influencing learners' foreign language learning.展开更多
Increasing tiller number is a target of high-yield rice breeding. Identification of tiller-defect mutants and their corresponding genes is helpful for clarifying the molecular mechanism of rice tillering. Summarizing ...Increasing tiller number is a target of high-yield rice breeding. Identification of tiller-defect mutants and their corresponding genes is helpful for clarifying the molecular mechanism of rice tillering. Summarizing research progress on the two processes of rice tiller formation, namely the formation and growth of axillary meristem, this paper reviews the effects of genetic factors, endogenous hormones, and exogenous environment on rice tillering, finding that multiple molecular mechanisms and signal pathways regulating rice tillering cooperate rice tillering, and discusses future research objectives and application of its regulatory mechanism. Elucidation of theis mechanism will be helpful for breeding high-yielding rice cultivars with ideal plant type via molecular design breeding.展开更多
This thesis investigates the causes of fossilization in English writing among two groups of English majors as well as the measures to deal with it. The experiment was conducted among 62 English majors from National Un...This thesis investigates the causes of fossilization in English writing among two groups of English majors as well as the measures to deal with it. The experiment was conducted among 62 English majors from National University of Defense Technology, and both their questionnaires and written texts were collected as the source of data analyzed. With data collected from questionnaires and written texts, the study aimed to explore （a） the causal factors leading to fossilization in writing, （b） the strategies to deal with students＇ fossilization. Relevant information was elicited from the questionnaire, written texts. Quantitative data were treated with SPSS for descriptive analysis and correlation analysis. The results indicated that both external and internal factors can lead to fossilization in English writing. The external factors include input, instruction and environment in the learning, and the internal factors incorporate students＇ interest, learning strategy, motivation with their systematic knowledge. Based on the results of the experiment, the author attempts to discuss measures to deal with fossilization.展开更多
Preterm labor(before 37 weeks’gestation)is the leading cause of neonatal mortality and morbidity,which can be divided into iatrogenic preterm labor,infectious preterm labor,and spontaneous preterm labor(sPTL).Up to n...Preterm labor(before 37 weeks’gestation)is the leading cause of neonatal mortality and morbidity,which can be divided into iatrogenic preterm labor,infectious preterm labor,and spontaneous preterm labor(sPTL).Up to now,there continue to be great difficulties in prediction and prevention of sPTL,owing to multiple risk factors,pathogenesis,and pathologic processes contributing to the event,which have not been fully clarified.Pregnancy maintenance and parturition is a complicated process with continuous maternal-fetal dialogue,in which both maternal and fetal factors participate and affect the outcome of pregnancy,including sPTL.Besides,external factors can also participate in sPTL,individually or through the interaction with internal factors.In this article,we summarize recent studies regarding sPTL from our and other groups,and discuss the risk factors and pathogenesis of preterm birth from both external and internal(maternal and fetal)aspects,so as to provide theoretical evidences for the diagnosis,prevention,and treatment of sPTL in the future.展开更多
It is very important to predict the coupling between the cavity and the high power input source in the coupler design. In this paper, a time domain method is used to calculate the external quality factor Qext for the ...It is very important to predict the coupling between the cavity and the high power input source in the coupler design. In this paper, a time domain method is used to calculate the external quality factor Qext for the BEPC Ⅱ superconducting cavity. A comparison between simulation results and experimental results is presented. The results of simulation and measurement of Qext have a good agreement within an error of 10%. The geometry parameters related with Qext are also studied.展开更多
It is a common phenomenon in international relations that the interaction between international actors leads to structural changes,which are often manifested as a positive friendly relationship or an escalation of con...It is a common phenomenon in international relations that the interaction between international actors leads to structural changes,which are often manifested as a positive friendly relationship or an escalation of contradictions or even conflicts among actors.Taking the relations between China and the Arab League as an example,this paper investigates the characteristics and influences of building friendly relations between the two sides.China-Arab relations are undergoing structural changes in the new era,generally reflected as follows:China and Arab countries enhance each other’s position in their overall diplomacy;there is a strategic docking between‘Looking East’of the Arab League and China’s‘Belt and Road Initiative’;China has become the second largest trading partner of the Arab League;ChinaArab cooperation has expanded in new frontiers such as high technology;the multilateral cooperation mechanism between China and Arab countries has been increasingly improved,and the strategic positioning of both sides has been constantly promoted.There are both internal and external driving forces to promote the structural upgrading of China-Arab relations.The former includes the economic interdependence between China and the Arab League,the changes in the policy orientation and priorities of the two sides,and the domestic political changes of Arab League countries,while the latter involves the changes in the surrounding situation of both sides,the changes in the international situation and the strategic contraction of the United States from the Middle East.The structural upgrading of China-Arab relations is conducive to the multi-polar development of the Middle East.Nevertheless,the two sides need to take precautions to cope with the changes in power,interests and identity brought about by this structural upgrading.展开更多
In 2018,summer precipitation was above normal in North and Northwest China and below normal around the Yangtze River valley,due to an extremely strong East Asian summer monsoon(EASM).The atmospheric circulation anomal...In 2018,summer precipitation was above normal in North and Northwest China and below normal around the Yangtze River valley,due to an extremely strong East Asian summer monsoon(EASM).The atmospheric circulation anomalies in East Asia and key external forcing factors that influence the EASM in 2018 are explored in this paper.The results show that there existed an anomalous cyclonic circulation near the Philippines,while the western Pacific subtropical high was located more northward than its normal position.In the mid–high latitudes,a negative geopotential height anomaly center was found near the Ural Mountains,suppressing the blocking activity.Under such a circulation pattern,precipitation near the Yangtze River valley decreased because local divergence and subsidence intensified,whereas precipitation in northern China increased due to large amounts of water vapor transport by anomalously strong southerly winds.Further analyses reveal that the strong EASM circulation in 2018 might result from the joint influences of several external forcing factors.The weak La Ni?a event that started from October 2017,the positive North Atlantic Tripolar mode(NAT)in spring 2018,and the reduced snow cover over the Tibetan Plateau in winter 2017/18 all collaboratively contributed to formation of the cyclonic circulation anomaly near the Philippines,leading to the extremely strong EASM.Especially,the positive NAT and the reduced Tibetan snow cover may have caused the negative geopotential height anomaly near the Ural Mountains,in favor of a strong EASM.The above external factors and their reinforcing impacts on the EASM are further verified by two groups of similar historical cases.展开更多
基金supported by the Nation Natural Science Foundation of China(NSFC)under Grant No.61462042 and No.61966018.
文摘Traffic flow prediction is an important part of the intelligent transportation system. Accurate multi-step traffic flow prediction plays an important role in improving the operational efficiency of the traffic network. Since traffic flow data has complex spatio-temporal correlation and non-linearity, existing prediction methods are mainly accomplished through a combination of a Graph Convolutional Network (GCN) and a recurrent neural network. The combination strategy has an excellent performance in traffic prediction tasks. However, multi-step prediction error accumulates with the predicted step size. Some scholars use multiple sampling sequences to achieve more accurate prediction results. But it requires high hardware conditions and multiplied training time. Considering the spatiotemporal correlation of traffic flow and influence of external factors, we propose an Attention Based Spatio-Temporal Graph Convolutional Network considering External Factors (ABSTGCN-EF) for multi-step traffic flow prediction. This model models the traffic flow as diffusion on a digraph and extracts the spatial characteristics of traffic flow through GCN. We add meaningful time-slots attention to the encoder-decoder to form an Attention Encoder Network (AEN) to handle temporal correlation. The attention vector is used as a competitive choice to draw the correlation between predicted states and historical states. We considered the impact of three external factors (daytime, weekdays, and traffic accident markers) on the traffic flow prediction tasks. Experiments on two public data sets show that it makes sense to consider external factors. The prediction performance of our ABSTGCN-EF model achieves 7.2%–8.7% higher than the state-of-the-art baselines.
文摘It is well known that English is the world language nowadays, and it is an official language in most countries. It is also currently the language most often taught as a foreign language. The reasons of the popularity lie in both internal factors and external factors. In this paper, the author will analyze the factors that help to push English into a popular world language.
文摘This case study on one Chinese EFL learner examined both the internal and external factors that affect Chinese EFL learner's speaking performance. Three interviews and three tests have been conducted in the whole process, and the findings revealed:(1) interference from first language is the most influential factor that hinders speaking performance;(2) learner attitude significantly affects speaking performance;(3) learning strategies and practicing help improving performance.
基金Supported by the National Natural Science Foundation of China (No.40646030)the National Agriculture Science and Technology Achievements Transfer Capital (No.2009GB2C2204)the Major Project of Zhejiang Province (No.2007C12061)
文摘Sperm motility is important in reproductive biology. To understand the physiological ecology characteristics of sperm of Sepiella maindroni, we studied the activation rate, active time, and lifespan of sperm to evaluate the influence of external factors, including temperature, salinity, pH, glucose, NaCl, KCl, MgCl2, CaCl2, EDTA-2Na and artificial seawater on sperm motility. The results show that the appropriate activation and motility condition for sperm were： temperature 20-30℃ （optimum 25℃）, salinity 10.6-30.6 （optimum 15.9） and pH 8.0-8.6 （optimum 8.0-8.4）. Sperm activity varied in different concentrations of glucose, NaCl, KCl, MgCl2 and CaCl〉 None of the selected concentrations of EDTA-2Na solution could activate the sperm. The activation rate in artificial seawater devoid of Ca2＋, Mg2＋ or HCO3- was low. The results should help further studies on the preservation and activation of squid sperm.
文摘Analysis of the problem of predicting bankruptcy shows that foreign and domestic models included only internal factors of enterprises. But the same indicators of internal factors in the rapidly changing external environment can lead to bankruptcy, and not in others. External factors are the most dangerous, because the possible influence on them is minimal and the impact of their implementation can be devastating. This paper focuses on the same factors to assess the impact of the macroeconomic indicators （extemal factors） on the parameters of static models predicting a local approximation of the crisis at the plant. To accomplish the purpose, a Spark set of 100 companies was compiled, including 50 companies which officially declared bankruptcy in the period of 2000-2009 and 50 stable operating companies with a random sample of the same time period. External factors were extracted from the Joint Economic and Social Data Archive1 The author compared two data sets： （1） microeconomic indicators--money to the total liabilities, retained earnings to total assets, net profit to revenue, Earnings Before Interest and Taxes （EBIT） to assets, net income to equity, net profit to total liabilities, current liabilities to total assets, the totality of short-term and long-term loans to total assets, current assets to current liabilities, assets to revenue, equity to total assets, and current assets to revenue; and （2） external factors--index of real gross domestic product （GDP）, industrial production index, the index of real cash incomes, an index of real investments, consumer price index, the refinancing rate, unemployment rate, the price of electricity, gas prices, oil price, gas price, dollar to ruble, ruble euro Standard ＆ Poor （S＆P） index, the Russian Trading System （RTS） index, and region. The aim of the comparison results paging classes ＂insolvent＂ and ＂non-bankrupt＂ is achieved using two methods： classification and discrimination. In both methods, computational procedures are realized with the use of algorithms linear regression, artificial neural network, and genetic algorithm. In the 2-m model, data set includes both internal and external factors. The results showed that the inclusion of only the microeconomic indicators, excluding external factors, impedes models about two times.
文摘The relationship between assessment and learning has gradually become a widely discussed topic in the field of education. The effective implementation of the assessment has a positive impact on promoting learning. This research is to collect learners' feedback on the related issues of process evaluation through questionnaires and analyze the data, explore the external influencing factors and causes of the effect of process evaluation, in order to correct some cognitive biases, avoid mistakes in the evaluation process, optimize the design of classroom evaluation activities, and improve the specific evaluation steps. The results of data analysis confirm that mutual evaluation and self-evaluation are the main influencing factors of process evaluation. Other external factors, such as whether teachers demonstrate the use of gauges, whether timely feedback is given, whether guidance is given to evaluation activities, and the number of evaluation components, all have an impact on the evaluation results. If teachers make use of the above factors locally, it will have a positive impact on the evaluation effect, otherwise, it will have a negative impact on the evaluation effect.
文摘With the continuous growth of the scale of China's foreign direct investment, more and more domestic enterprises begin to choose "going out", which not only expands the international influence of the enterprises themselves, but also makes an important contribution to China's economic development. With the implementation of the national "go globally" strategy, industrial gas enterprises can also expand their market. Different from inward investment, outward investment has its special complexity and uncertainty, so it is very important to explore its influencing factors. However, the external investment of industrial gas is influenced by both the external environment and the risks of gas supply customers. In this paper, the influence of the uncertainty of the main external factors on the foreign direct investment of gas enterprises is briefly described.
文摘For many years, scholars have been studying the factors that influence foreign language learning. Generally speaking,the factors that influence foreign language learning can be divided into internal and external factors. Whether internal or external factors, they are interconnected in playing their different roles in learners' process of acquiring a foreign language. Internal factors are things like learners' age, intelligence, language aptitude, attitude, personality, etc while design of curriculum, teachers' instruction, the status of target language culture, and access to native speakers can be categorized into external factors influencing learners' foreign language learning.
基金supported by the National Natural Science Foundation of China (32071993, 32188102, 31971872, 31861143006,U2004204)Key Agricultural Technology Project(NK2022010302)。
文摘Increasing tiller number is a target of high-yield rice breeding. Identification of tiller-defect mutants and their corresponding genes is helpful for clarifying the molecular mechanism of rice tillering. Summarizing research progress on the two processes of rice tiller formation, namely the formation and growth of axillary meristem, this paper reviews the effects of genetic factors, endogenous hormones, and exogenous environment on rice tillering, finding that multiple molecular mechanisms and signal pathways regulating rice tillering cooperate rice tillering, and discusses future research objectives and application of its regulatory mechanism. Elucidation of theis mechanism will be helpful for breeding high-yielding rice cultivars with ideal plant type via molecular design breeding.
文摘This thesis investigates the causes of fossilization in English writing among two groups of English majors as well as the measures to deal with it. The experiment was conducted among 62 English majors from National University of Defense Technology, and both their questionnaires and written texts were collected as the source of data analyzed. With data collected from questionnaires and written texts, the study aimed to explore （a） the causal factors leading to fossilization in writing, （b） the strategies to deal with students＇ fossilization. Relevant information was elicited from the questionnaire, written texts. Quantitative data were treated with SPSS for descriptive analysis and correlation analysis. The results indicated that both external and internal factors can lead to fossilization in English writing. The external factors include input, instruction and environment in the learning, and the internal factors incorporate students＇ interest, learning strategy, motivation with their systematic knowledge. Based on the results of the experiment, the author attempts to discuss measures to deal with fossilization.
基金supported by National Key Research and Development Project No.2019YFC1005203National Natural Science Foundation of China No.81771608 and 82120108011+2 种基金Major Project of Shanghai Municipal Education Commission’s Scientific Research and Innovation Plan No.2021-01-07-00-07-E00144“Dawn”Program of Shanghai Education Commission No.17SG36The Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning.
文摘Preterm labor(before 37 weeks’gestation)is the leading cause of neonatal mortality and morbidity,which can be divided into iatrogenic preterm labor,infectious preterm labor,and spontaneous preterm labor(sPTL).Up to now,there continue to be great difficulties in prediction and prevention of sPTL,owing to multiple risk factors,pathogenesis,and pathologic processes contributing to the event,which have not been fully clarified.Pregnancy maintenance and parturition is a complicated process with continuous maternal-fetal dialogue,in which both maternal and fetal factors participate and affect the outcome of pregnancy,including sPTL.Besides,external factors can also participate in sPTL,individually or through the interaction with internal factors.In this article,we summarize recent studies regarding sPTL from our and other groups,and discuss the risk factors and pathogenesis of preterm birth from both external and internal(maternal and fetal)aspects,so as to provide theoretical evidences for the diagnosis,prevention,and treatment of sPTL in the future.
基金Supported by National Natural Science Foundation of China(k711360503)
文摘It is very important to predict the coupling between the cavity and the high power input source in the coupler design. In this paper, a time domain method is used to calculate the external quality factor Qext for the BEPC Ⅱ superconducting cavity. A comparison between simulation results and experimental results is presented. The results of simulation and measurement of Qext have a good agreement within an error of 10%. The geometry parameters related with Qext are also studied.
基金the National Social Science Foundation of China project‘The Theory and Practice approaches of the League of Arab States’[No.19FGJB015]National Social Science Fund of China‘China’s overall diplomacy towards Arab countries under the framework of the"China-Arab Cooperation Forum"[No.19AGJ010]。
文摘It is a common phenomenon in international relations that the interaction between international actors leads to structural changes,which are often manifested as a positive friendly relationship or an escalation of contradictions or even conflicts among actors.Taking the relations between China and the Arab League as an example,this paper investigates the characteristics and influences of building friendly relations between the two sides.China-Arab relations are undergoing structural changes in the new era,generally reflected as follows:China and Arab countries enhance each other’s position in their overall diplomacy;there is a strategic docking between‘Looking East’of the Arab League and China’s‘Belt and Road Initiative’;China has become the second largest trading partner of the Arab League;ChinaArab cooperation has expanded in new frontiers such as high technology;the multilateral cooperation mechanism between China and Arab countries has been increasingly improved,and the strategic positioning of both sides has been constantly promoted.There are both internal and external driving forces to promote the structural upgrading of China-Arab relations.The former includes the economic interdependence between China and the Arab League,the changes in the policy orientation and priorities of the two sides,and the domestic political changes of Arab League countries,while the latter involves the changes in the surrounding situation of both sides,the changes in the international situation and the strategic contraction of the United States from the Middle East.The structural upgrading of China-Arab relations is conducive to the multi-polar development of the Middle East.Nevertheless,the two sides need to take precautions to cope with the changes in power,interests and identity brought about by this structural upgrading.
基金the National Key Research and Development Program of China(2018YFC1506006)National Science and Technology Support Program of China(2015BAC03B04)National Natural Science Foundation of China(41805067 and 41275073)
文摘In 2018,summer precipitation was above normal in North and Northwest China and below normal around the Yangtze River valley,due to an extremely strong East Asian summer monsoon(EASM).The atmospheric circulation anomalies in East Asia and key external forcing factors that influence the EASM in 2018 are explored in this paper.The results show that there existed an anomalous cyclonic circulation near the Philippines,while the western Pacific subtropical high was located more northward than its normal position.In the mid–high latitudes,a negative geopotential height anomaly center was found near the Ural Mountains,suppressing the blocking activity.Under such a circulation pattern,precipitation near the Yangtze River valley decreased because local divergence and subsidence intensified,whereas precipitation in northern China increased due to large amounts of water vapor transport by anomalously strong southerly winds.Further analyses reveal that the strong EASM circulation in 2018 might result from the joint influences of several external forcing factors.The weak La Ni?a event that started from October 2017,the positive North Atlantic Tripolar mode(NAT)in spring 2018,and the reduced snow cover over the Tibetan Plateau in winter 2017/18 all collaboratively contributed to formation of the cyclonic circulation anomaly near the Philippines,leading to the extremely strong EASM.Especially,the positive NAT and the reduced Tibetan snow cover may have caused the negative geopotential height anomaly near the Ural Mountains,in favor of a strong EASM.The above external factors and their reinforcing impacts on the EASM are further verified by two groups of similar historical cases.
