A three-year experiment was conducted to investigate and compare the economic and ecological benefits of six types of vegetation management measures in citrus orchards of the hilly red soil region of the eastern part ...A three-year experiment was conducted to investigate and compare the economic and ecological benefits of six types of vegetation management measures in citrus orchards of the hilly red soil region of the eastern part of China.Six vegetation treatments,including tillage without herbicide(clean tillage)and no tillage without herbicide(sod culture) and with herbicide paraquat(paraquat),glyphosate(glyphosate),glyphosate-glyphosate-paraquat(G-G-P),and paraquat- paraquat-glyphosate(P-P-G),were applied in the citrus orchards on a clayey red soil with slopes of 8°and 13°and a sandy soil with slope of 25°.The results showed that the sod culture,paraquat,glyphosate,G-G-P,and P-P-G treatments reduced surface runoff by 38.8%,42.5%,18.7%,28.7%,and 37.5%,then the soil-water losses by 55.5%,51.7%,39.9%,46.8%, and 50.0%,and the N,P,and K nutrient losses by 60.3%,50.2%,37.0%,41.8%,and 45.4%,respectively,as compared with the clean tillage treatment.The weed regeneration ratios with the treatments of clean tillage without herbicide,paraquat, glyphosate,G-G-P,and P-P-G were reduced by 55.1%,67.2%,30.3%,36.8%,and 51.2%,respectively,as compared with the sod culture.The sod culture,paraquat,glyphosate,G-G-P,and P-P-G treatments could increase the soil fertility (annual accumulation of N,P,K,and OM)by 7.1%,6.9%,5.3%,6.2%,and 6.6%,respectively,whereas the clean tillage treatment without herbicide reduced soil fertility by 4.4% after the three-year experiment.The citrus fruit yields in the treatments of paraquat,glyphosate,G-G-P,and P-P-G increased by 7%-10%;the soluble solid,total sugar,total acidity,sugar-acid ratio,and single fruit weight of citrus fruits of all treatments except sod culture significantly(P>0.05) exceeded that of the clean tillage treatment.In general,the paraquat treatment showed the best economic and ecological benefits among the six treatments;therefore,it could be regarded as the best available vegetation management measure in citrus orchards of hilly red soil region to retain water and soil,enhance soil fertility,and improve the yield and quality of citrus.展开更多
With the rapidly developing economy,the evolution of science technology improves at a high speed.At the same time,a new technology is born which we called Micro-Class.It has been used widely in high education within a...With the rapidly developing economy,the evolution of science technology improves at a high speed.At the same time,a new technology is born which we called Micro-Class.It has been used widely in high education within a short time.The facts indicate,it is helpful to put flipped classroom model into college English lecture environment.The new model not only makes difference in motivating the students' interests of studying,but also improves their autonomy for studying and the participatory for class activities.In terms of this situation,I will make a pointed statement as follow.展开更多
This paper investigates traffic flow of connected and automated vehicles at lane drop on two-lane highway. We evaluate and compare performance of an optimization-based control algorithm(OCA) with that of a heuristic r...This paper investigates traffic flow of connected and automated vehicles at lane drop on two-lane highway. We evaluate and compare performance of an optimization-based control algorithm(OCA) with that of a heuristic rules-based algorithm(HRA). In the OCA, the average speed of each vehicle is maximized. In the HRA, virtual vehicle and restriction of the command acceleration caused by the virtual vehicle are introduced. It is found that(i) capacity under the HRA(denoted as C_(H)) is smaller than capacity under the OCA;(ii) the travel delay is always smaller under the OCA, but driving is always much more comfortable under the HRA;(iii) when the inflow rate is smaller than C_(H), the HRA outperforms the OCA with respect to the fuel consumption and the monetary cost;(iv) when the inflow rate is larger than C_(H), the HRA initially performs better with respect to the fuel consumption and the monetary cost, but the OCA would become better after certain time. The spatiotemporal pattern and speed profile of traffic flow are presented, which explains the reason underlying the different performance. The study is expected to help for better understanding of the two different types of algorithm.展开更多
Graduate education is the main way to train high-level innovative talents,the basic layout to cope with the global talent competition,and the important cornerstone for implementing the innovation-driven development st...Graduate education is the main way to train high-level innovative talents,the basic layout to cope with the global talent competition,and the important cornerstone for implementing the innovation-driven development strategy and building an innovation-driven country.Therefore,graduate education is of great remarkably to the development of national education.As an important manifestation of graduate education,the quality of a graduate thesis should receive more attention.It is conducive to promoting the quality of graduates by supervising and examining the quality of the graduate thesis.For this purpose,this work is based on textmining,expert interviews,and questionnaire surveys to obtain the factors influencing the quality of a graduate thesis first.Then,through three rounds of expert consultation,a multidimensional evaluation indicator system for the graduate thesis quality is built.Furthermore,probabilistic linguistic termsets(PLTSs)are utilized to obtain the initial evaluation information and apply the stepwise weight assessment ratio analysis method to determine the weights of attributes.In the ensuing step,the novel multi-attribute border approximation area comparison based on the PLTS method is established.Finally,the proposed method is employed in a case study concerning the quality evaluation of a graduate thesis and the effectiveness of this approach is further illustrated.展开更多
The nonlinear radiation of the electron is a distinctive feature of the action of tightly focused linearly polarized lasers.In this paper,from the perspective of radiation symmetry,the effect of laser parameters on th...The nonlinear radiation of the electron is a distinctive feature of the action of tightly focused linearly polarized lasers.In this paper,from the perspective of radiation symmetry,the effect of laser parameters on the electron radiation power in the time domain is studied systematically.An asymmetric bimodal structure is found in the time domain in the direction of the maximum radiation.For this special structure,an explanation is given based on the electron dynamics perspective.The structure is compared with the symmetric bimodal structure in the classical theory.The increase in laser intensity,while significantly increasing the radiated power of the electron,exacerbates the asymmetry of the electron radiation.The variation in the initial phase of the laser leads to a periodic variation in the electron motion,which results in a periodic extension of the electron spatial radiation with a period ofπ.Moreover,the existence of jump points with a phase difference ofπin the range of 0-2πis found.The increase in pulse width reduces the radiated power,extends the radiation range,and alleviates the radiation asymmetry.The results in this paper contribute to the study of electron radiation characteristics in intense laser fields.展开更多
In order to cultivate information literacy among college students,the Chinese government has formulated a series of relevant policies as well as revised and adjusted the policy priorities along with the times.Guided b...In order to cultivate information literacy among college students,the Chinese government has formulated a series of relevant policies as well as revised and adjusted the policy priorities along with the times.Guided by co-word and social network analysis,this study analyzes 170 policy texts that have been promulgated by the Chinese government from 1981 to 2020.Based on the clustering results of high-frequency keywords,this study explores the characteristics of policy evolution and its influencing factors from three dimensions:policy themes,contents of information literacy education,and the methods for cultivating information literacy education.Several suggestions have also been put forward in this article to improve the information literacy education policy for Chinese college students.展开更多
This paper addresses the problem of predicting population density leveraging cellular station data.As wireless communication devices are commonly used,cellular station data has become integral for estimating populatio...This paper addresses the problem of predicting population density leveraging cellular station data.As wireless communication devices are commonly used,cellular station data has become integral for estimating population figures and studying their movement,thereby implying significant contributions to urban planning.However,existing research grapples with issues pertinent to preprocessing base station data and the modeling of population prediction.To address this,we propose methodologies for preprocessing cellular station data to eliminate any irregular or redundant data.The preprocessing reveals a distinct cyclical characteristic and high-frequency variation in population shift.Further,we devise a multi-view enhancement model grounded on the Transformer(MVformer),targeting the improvement of the accuracy of extended time-series population predictions.Comparative experiments,conducted on the above-mentioned population dataset using four alternate Transformer-based models,indicate that our proposedMVformer model enhances prediction accuracy by approximately 30%for both univariate and multivariate time-series prediction assignments.The performance of this model in tasks pertaining to population prediction exhibits commendable results.展开更多
The present study examines the impact of short-term public opinion sentiment on the secondary market,with a focus on the potential for such sentiment to cause dramatic stock price fluctuations and increase investment ...The present study examines the impact of short-term public opinion sentiment on the secondary market,with a focus on the potential for such sentiment to cause dramatic stock price fluctuations and increase investment risk.The quantification of investment sentiment indicators and the persistent analysis of their impact has been a complex and significant area of research.In this paper,a structured multi-head attention stock index prediction method based adaptive public opinion sentiment vector is proposed.The proposedmethod utilizes an innovative approach to transform numerous investor comments on social platforms over time into public opinion sentiment vectors expressing complex sentiments.It then analyzes the continuous impact of these vectors on the market through the use of aggregating techniques and public opinion data via a structured multi-head attention mechanism.The experimental results demonstrate that the public opinion sentiment vector can provide more comprehensive feedback on market sentiment than traditional sentiment polarity analysis.Furthermore,the multi-head attention mechanism is shown to improve prediction accuracy through attention convergence on each type of input information separately.Themean absolute percentage error(MAPE)of the proposedmethod is 0.463%,a reduction of 0.294% compared to the benchmark attention algorithm.Additionally,the market backtesting results indicate that the return was 24.560%,an improvement of 8.202% compared to the benchmark algorithm.These results suggest that themarket trading strategy based on thismethod has the potential to improve trading profits.展开更多
Objective:To provide high-quality clinical evidence of the efficacy of Tibetan medicine Honghua Ruyi(HHRY)pills for endometriosis-associated dysmenorrhea.Methods:This study constitutes a multicenter,randomized,double-...Objective:To provide high-quality clinical evidence of the efficacy of Tibetan medicine Honghua Ruyi(HHRY)pills for endometriosis-associated dysmenorrhea.Methods:This study constitutes a multicenter,randomized,double-blind,placebo-controlled trial encompassing a three-menstrual cycle intervention followed by a three-menstrual cycle follow-up period.A total of 164 eligible females with endometriosis-associated dysmenorrhea were randomly divided into HHRY pills and placebo groups in a 1:1 ratio.The primary outcome included dysmenorrhea symptoms assessed using Visual Analog Scale(VAS)scores and quality of life,whereas the secondary outcome measures included the maximum VAS for non-menstrual pelvic pain,duration of pain episodes(in days),frequency and quantity of the consumption of ibuprofen sustained-release capsules(or other non-steroidal anti-inflammatory drugs),and days off work/study for staff/student due to dysmenorrhea,ovarian cyst,and/or pelvic nodule size.The safety was monitored throughout the treatment period.All the analyses were based on the intention-to-treat principle.For continuous outcomes,simple or multiple linear regressions were used to estimate the differences between the HHRY pills and placebo groups,with categorical data expressed as the number and percentage of occurrences.Differences were compared using the chi-square test or Fisher's exact test.The predefined analysis was adjusted for concomitant treatment,a variable considered to be associated with outcomes but unaffected by treatment allocation.Estimates of treatment effects were reported with 95%confidence intervals.Two-tailed P values≤.05 were considered statistically significant.Conclusion:Positive results from this trial,upon completion would provide robust evidence for the efficacy and safety of HHRY pills in treating dysmenorrhea in patients with endometriosis.展开更多
In recent years, there has been increasing research interests in differentiating the relative importance of climate factors and human activities in impacting vegetation dynamics. In this study, based on residual trend...In recent years, there has been increasing research interests in differentiating the relative importance of climate factors and human activities in impacting vegetation dynamics. In this study, based on residual trend method, we used MOD13A3(MODIS vegetation index product), MCD12Q1(MODIS land cover product) and meteorological datasets to differentiate the relative importance of climate factors and human activities in impacting vegetation dynamics during 2000–2015 in the Otindag Sandy Land, northern China. Results show that during the study period(2000–2015), the overall vegetation condition had improved in the Otindag Sandy Land. The driving forces of vegetation dynamics differed spatially in the whole study area over the study period. The area with vegetation degradation solely resulted from human activities accounted for 8.23% of the study area, while the area with vegetation degradation resulted from others(including climate factors and combination of climate factors and human activities) occupied 1.53%. The area with vegetation recovery benefitted from human activities occurred over 26.02% of the study area; the area benefitted from climate factors accounted for 23.69%; and the area benefitted from both climate factors and human activities occupied 37.74%. All in all, impacts of climate factors and human activities on vegetation dynamics varied at the county/city/banner scales and locality-specific measures should be adopted to protect the environments.展开更多
Profile monitoring is used to check the stability of the quality of a product over time when the product quality is best represented by a function at each time point.However,most previous monitoring approaches have no...Profile monitoring is used to check the stability of the quality of a product over time when the product quality is best represented by a function at each time point.However,most previous monitoring approaches have not considered that the argument values may vary from profile to profile,which is common in practice.A novel nonparametric control scheme based on profile error is proposed for monitoring nonlinear profiles with varied argument values.The proposed scheme uses the metrics of profile error as the statistics to construct the control charts.More details about the design of this nonparametric scheme are also discussed.The monitoring performance of the combined control scheme is compared with that of alternative nonparametric methods via simulation.Simulation studies show that the combined scheme is effective in detecting parameter error and is sensitive to small shifts in the process.In addition,due to the properties of the charting statistics,the out-of-control signal can provide diagnostic information for the users.Finally,the implementation steps of the proposed monitoring scheme are given and applied for monitoring the blade manufacturing process.With the application in blade manufacturing of aircraft engines,the proposed nonparametric control scheme is effective,interpretable,and easy to apply.展开更多
The systematic clustering analysis based weight determination methods are suitable for the experts of complex multiattribute large-group decision-making(CMALGDM) in intervalvalued intuitionistic fuzzy environment. How...The systematic clustering analysis based weight determination methods are suitable for the experts of complex multiattribute large-group decision-making(CMALGDM) in intervalvalued intuitionistic fuzzy environment. However, these methods mainly have two shortcomings: they do not consider the consistency of the experts in each aggregation; the aggregation weights are often determined simply by the "majority principle", and neglect the quantity of information provided by the holistic aggregation,leading to decision biases. Hence, a double weight determination method for experts is proposed to solve these problems. As for the first shortcoming, a mathematical programming model is used to solve for the optimal expert weights within each aggregation,ensuring consistency in the overall preferences of the aggregations. As for the second shortcoming, we propose a modification of the aggregation weights based on the information entropy, which fully considers both the number of experts and the amount of information provided by the holistic aggregation. With the proposed method, the final expert weights are determined more rigorously and objectively. The feasibility of the proposed method is investigated through an illustrative example.展开更多
For the scientific management of farmland,it is significant to understand the spatio-temporal variability of soil organic matter and to study the influences of related factors.Using geostatistical theory,GIS spatial a...For the scientific management of farmland,it is significant to understand the spatio-temporal variability of soil organic matter and to study the influences of related factors.Using geostatistical theory,GIS spatial analysis,trend analysis and a Geographically Weighted Regression(GWR)model,this study analyzed the response of soil organic matter to climate and socio-economic factors in central Heilongjiang Province during the past 25 years.Second soil survey data of China for 1979-1985,2005 field sampling data,climate observations and socio-economic data for 1980-2005 were analyzed.First,soil organic matter in 2005 was spatially interpolated using the Co-Kriging method along with auxiliary data sets of soil type and pH.The spatio-temporal variability was then studied by comparison with the 1980s second soil census data.Next,the temporal trends in climate and socio-economic factors over the past 25 years were investigated.Finally,we examined the variation of the response of soil organic matter to climate and socio-economic factors using the GWR model spatially and temporally.The model showed that 53.82%area of the organic matter content remained constant and 29.39%has decreased during the past 25 years.The impact of precipitation on organic matter content is mainly negative,with increasing absolute values of the regression coefficient.The absolute value of regression coefficient of annual average temperature has decreased,and more areas are now under its negative effects.In addition,the areas of positive regression coefficient of annual sunshine hours have northward shifted,with the increasing absolute value of positive coefficient and decreasing absolute value of negative coefficient.The areas of positive regression coefficient of mechanized farming as a socio-economic factor have westward shifted,with the increasing absolute value of negative coefficient and decreasing absolute value of positive coefficient.The area of regions with the positive regression coefficient of irrigation has expanded.The regions with positive regression coefficient of fertilizer use have shrinked.The positive regression coefficient of mulch film consumption has significantly increased.The regression coefficient of pesticide consumption was mainly positive in the west of the study area,while it was negative to the east.Generally,GWR model is capable to investigate the influence of both climatic and socio-economic factors,avoided the insufficiency of other research based on the single perspective of climatic or socio-economic factors.Therefore,we can conclude that GWR model could provide methodological support for global change research and serve as basic reference for cultivated land quality improvement and agricultural decision making.展开更多
The influence of labor migration on rural household land transfer has been hotly debated in academic circles, which focuses on whether part-time employment leads to land transfer. Using survey data on rural households...The influence of labor migration on rural household land transfer has been hotly debated in academic circles, which focuses on whether part-time employment leads to land transfer. Using survey data on rural households in the Sichuan Province, and applying the theoretical framework of new economics of labor migration, this study explores the influences of labor migration on the direction and scale of land transfer from the perspective of rural household structure. The results indicate that: 1) the quantity of laborers has significant influence on the direction and scale of land transfer. The larger the on-farm labor variable(Labor), the lesser the possibility that land will be rented-out and the amount of land rented out will also be smaller. In addition, there is a greater probability that land will be rented-in and the amount of land rented-in will be greater. 2) The greater the ratio of off-farm laborers to rural household laborers(Off-farm) the greater the possibility that land will be rented-out. In addition the higher the ratio of on-farm laborers to the total household laborers(On-farm), the larger the possibility that land will be rented-in. Meanwhile, if the household has individuals at the age of 64 or older(Old) who are engaged in agriculture, there is a smaller possibility that land will be rentedout. 3) the ratio of part-time laborers to rural household laborers(Pluriactivity) have significant inverse U-shaped influences on the rent-in of land as well as the amount of land rented-in. The inflection points are 33.27% and 14.10%, respectively. Such findings confirm the significance of this study in better understanding the influence of labor migration on rural household land transfer.展开更多
In order to rectify the problems that the component reliability model exhibits deviation, and the evaluation result is low due to the overlook of failure propagation in traditional reliability evaluation of machine ce...In order to rectify the problems that the component reliability model exhibits deviation, and the evaluation result is low due to the overlook of failure propagation in traditional reliability evaluation of machine center components, a new reliability evaluation method based on cascading failure analysis and the failure influenced degree assessment is proposed. A direct graph model of cascading failure among components is established according to cascading failure mechanism analysis and graph theory. The failure influenced degrees of the system components are assessed by the adjacency matrix and its transposition, combined with the Pagerank algorithm.Based on the comprehensive failure probability function and total probability formula, the inherent failure probability function is determined to realize the reliability evaluation of the system components. Finally, the method is applied to a machine center, it shows the following: 1)The reliability evaluation values of the proposed method are at least 2.5% higher than those of the traditional method; 2) The difference between the comprehensive and inherent reliability of the system component presents a positive correlation with the failure influenced degree ofthe system component, which provides a theoretical basis for reliability allocation of machine center system.展开更多
In this study, the solar thermochemical reactor performance for CO_2 utilization into synthesis gas(H_2+ CO) based on CH_4 reforming process was investigated in the context of carbon capture and utilization(CCU) techn...In this study, the solar thermochemical reactor performance for CO_2 utilization into synthesis gas(H_2+ CO) based on CH_4 reforming process was investigated in the context of carbon capture and utilization(CCU) technologies. The P1 radiation heat transfer model is adopted to establish the heat and mass transfer model coupled with thermochemical reaction kinetics. The reactor thermal behavior with direct heat transfer between gaseous reactant and products evolution and the effects of different structural parameters were evaluated. It was found that the reactor has the potential to utilize by ～60% of CO_2 captured with 40% of CH_4 co-fed into syngas(72.9% of H_2 and 27.1% of CO) at 741.31 k W/mof incident radiation heat flux. However, the solar irradiance heat flux and temperature distribution were found to significantly affect the reactant species conversion efficiency and syngas production. The chemical reaction is mainly driven by the thermal energy and higher species conversion into syngas was observed when the temperature distribution at the inner cavity of the reactor was more uniform. Designed a solar thermochemical reactor able to volumetric store concentrated irradiance could highly improve CCU technologies for producing energy-rich chemicals. Besides, the mixture gas inlet velocity, operating pressure and CO_2/CH_4 feeding ratio were crucial to determining the efficiency of CO_2 utilization to solar fuels. Catalytic CO_2-reforming of CH_4 to chemical energy is a promising strategy for an efficient utilization of CO_2 as a renewable carbon source.展开更多
This paper deals mainly with the influence of lane changing behaviours on the stability of two-lane traffic flow under a periodic boundary condition.Following the description of an optimal velocity model for two vehic...This paper deals mainly with the influence of lane changing behaviours on the stability of two-lane traffic flow under a periodic boundary condition.Following the description of an optimal velocity model for two vehicle groups and the derivation of their stability conditions,the feedback signals,which involve information about vehicles from both lanes acting on the two-lane traffic system,are introduced into the optimal velocity model.The control signals play a role in alleviating the traffic jam only if the traffic state is in congestion,and their role will vanish if the traffic state is in the steady state.The numerical simulations show that lane changing behaviours can break the steady state of two-lane traffic flow and aggravate the traffic disturbance,but the control method would successfully suppress the traffic jam eventually,which implies that the conclusions obtained here have certain theoretical and practical significance.展开更多
In this paper, the cement paste and the mortar were tested using the PF-QNM technique. It is shown that the PF-QNM technique is very powerful to characterize the mechanical properties of micro-and nanostructures in th...In this paper, the cement paste and the mortar were tested using the PF-QNM technique. It is shown that the PF-QNM technique is very powerful to characterize the mechanical properties of micro-and nanostructures in the cement-based materials. It does not have strict requirements for test environment and it does not damage the surface of the material. High-resolution images can be obtained very easily, and they can be analyzed statistically. The test results show that PF-QNM analysis can test not only the mechanical properties of the cement paste, but also investigate the interfacial regions in the cement-based material, including the variation in the mechanical properties of interface regions and the extension of the interfacial regions. During the test, care must be taken to choose the size of test area;indeed, a test area too small is not representative but too large leads to lack of stability. The recommended side is a square with a length of in the range 10-30 μm.展开更多
This paper expresses the efficient outputs of decisionmaking unit(DMU) as the sum of "average outputs" forecasted by a GM(1,N) model and "increased outputs" which reflect the difficulty to realize ...This paper expresses the efficient outputs of decisionmaking unit(DMU) as the sum of "average outputs" forecasted by a GM(1,N) model and "increased outputs" which reflect the difficulty to realize efficient outputs.The increased outputs are solved by linear programming using data envelopment analysis efficiency theories,wherein a new sample is introduced whose inputs are equal to the budget in the issue No.n + 1 and outputs are forecasted by the GM(1,N) model.The shortcoming in the existing methods that the forecasted efficient outputs may be less than the possible actual outputs according to developing trends of input-output rate in the periods of pre-n is overcome.The new prediction method provides decision-makers with more decisionmaking information,and the initial conditions are easy to be given.展开更多
文摘A three-year experiment was conducted to investigate and compare the economic and ecological benefits of six types of vegetation management measures in citrus orchards of the hilly red soil region of the eastern part of China.Six vegetation treatments,including tillage without herbicide(clean tillage)and no tillage without herbicide(sod culture) and with herbicide paraquat(paraquat),glyphosate(glyphosate),glyphosate-glyphosate-paraquat(G-G-P),and paraquat- paraquat-glyphosate(P-P-G),were applied in the citrus orchards on a clayey red soil with slopes of 8°and 13°and a sandy soil with slope of 25°.The results showed that the sod culture,paraquat,glyphosate,G-G-P,and P-P-G treatments reduced surface runoff by 38.8%,42.5%,18.7%,28.7%,and 37.5%,then the soil-water losses by 55.5%,51.7%,39.9%,46.8%, and 50.0%,and the N,P,and K nutrient losses by 60.3%,50.2%,37.0%,41.8%,and 45.4%,respectively,as compared with the clean tillage treatment.The weed regeneration ratios with the treatments of clean tillage without herbicide,paraquat, glyphosate,G-G-P,and P-P-G were reduced by 55.1%,67.2%,30.3%,36.8%,and 51.2%,respectively,as compared with the sod culture.The sod culture,paraquat,glyphosate,G-G-P,and P-P-G treatments could increase the soil fertility (annual accumulation of N,P,K,and OM)by 7.1%,6.9%,5.3%,6.2%,and 6.6%,respectively,whereas the clean tillage treatment without herbicide reduced soil fertility by 4.4% after the three-year experiment.The citrus fruit yields in the treatments of paraquat,glyphosate,G-G-P,and P-P-G increased by 7%-10%;the soluble solid,total sugar,total acidity,sugar-acid ratio,and single fruit weight of citrus fruits of all treatments except sod culture significantly(P>0.05) exceeded that of the clean tillage treatment.In general,the paraquat treatment showed the best economic and ecological benefits among the six treatments;therefore,it could be regarded as the best available vegetation management measure in citrus orchards of hilly red soil region to retain water and soil,enhance soil fertility,and improve the yield and quality of citrus.
文摘With the rapidly developing economy,the evolution of science technology improves at a high speed.At the same time,a new technology is born which we called Micro-Class.It has been used widely in high education within a short time.The facts indicate,it is helpful to put flipped classroom model into college English lecture environment.The new model not only makes difference in motivating the students' interests of studying,but also improves their autonomy for studying and the participatory for class activities.In terms of this situation,I will make a pointed statement as follow.
基金Project supported in part by the Fundamental Research Funds for the Central Universities (Grant No.2021JBZ107)the National Natural Science Foundation of China (Grant Nos.72288101 and 71931002)。
文摘This paper investigates traffic flow of connected and automated vehicles at lane drop on two-lane highway. We evaluate and compare performance of an optimization-based control algorithm(OCA) with that of a heuristic rules-based algorithm(HRA). In the OCA, the average speed of each vehicle is maximized. In the HRA, virtual vehicle and restriction of the command acceleration caused by the virtual vehicle are introduced. It is found that(i) capacity under the HRA(denoted as C_(H)) is smaller than capacity under the OCA;(ii) the travel delay is always smaller under the OCA, but driving is always much more comfortable under the HRA;(iii) when the inflow rate is smaller than C_(H), the HRA outperforms the OCA with respect to the fuel consumption and the monetary cost;(iv) when the inflow rate is larger than C_(H), the HRA initially performs better with respect to the fuel consumption and the monetary cost, but the OCA would become better after certain time. The spatiotemporal pattern and speed profile of traffic flow are presented, which explains the reason underlying the different performance. The study is expected to help for better understanding of the two different types of algorithm.
文摘Graduate education is the main way to train high-level innovative talents,the basic layout to cope with the global talent competition,and the important cornerstone for implementing the innovation-driven development strategy and building an innovation-driven country.Therefore,graduate education is of great remarkably to the development of national education.As an important manifestation of graduate education,the quality of a graduate thesis should receive more attention.It is conducive to promoting the quality of graduates by supervising and examining the quality of the graduate thesis.For this purpose,this work is based on textmining,expert interviews,and questionnaire surveys to obtain the factors influencing the quality of a graduate thesis first.Then,through three rounds of expert consultation,a multidimensional evaluation indicator system for the graduate thesis quality is built.Furthermore,probabilistic linguistic termsets(PLTSs)are utilized to obtain the initial evaluation information and apply the stepwise weight assessment ratio analysis method to determine the weights of attributes.In the ensuing step,the novel multi-attribute border approximation area comparison based on the PLTS method is established.Finally,the proposed method is employed in a case study concerning the quality evaluation of a graduate thesis and the effectiveness of this approach is further illustrated.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.10947170/A05 and 11104291)Natural Science Fund for Colleges and Universities in Jiangsu Province (Grant No.10KJB140006)+2 种基金Natural Science Foundation of Shanghai (Grant No.11ZR1441300)Natural Science Foundation of Nanjing University of Posts and Telecommunications (Grant No.NY221098)sponsored by the Jiangsu Qing Lan Project and STITP Project (Grant No.CXXYB2022516)。
文摘The nonlinear radiation of the electron is a distinctive feature of the action of tightly focused linearly polarized lasers.In this paper,from the perspective of radiation symmetry,the effect of laser parameters on the electron radiation power in the time domain is studied systematically.An asymmetric bimodal structure is found in the time domain in the direction of the maximum radiation.For this special structure,an explanation is given based on the electron dynamics perspective.The structure is compared with the symmetric bimodal structure in the classical theory.The increase in laser intensity,while significantly increasing the radiated power of the electron,exacerbates the asymmetry of the electron radiation.The variation in the initial phase of the laser leads to a periodic variation in the electron motion,which results in a periodic extension of the electron spatial radiation with a period ofπ.Moreover,the existence of jump points with a phase difference ofπin the range of 0-2πis found.The increase in pulse width reduces the radiated power,extends the radiation range,and alleviates the radiation asymmetry.The results in this paper contribute to the study of electron radiation characteristics in intense laser fields.
文摘In order to cultivate information literacy among college students,the Chinese government has formulated a series of relevant policies as well as revised and adjusted the policy priorities along with the times.Guided by co-word and social network analysis,this study analyzes 170 policy texts that have been promulgated by the Chinese government from 1981 to 2020.Based on the clustering results of high-frequency keywords,this study explores the characteristics of policy evolution and its influencing factors from three dimensions:policy themes,contents of information literacy education,and the methods for cultivating information literacy education.Several suggestions have also been put forward in this article to improve the information literacy education policy for Chinese college students.
基金Guangdong Basic and Applied Basic Research Foundation under Grant No.2024A1515012485in part by the Shenzhen Fundamental Research Program under Grant JCYJ20220810112354002.
文摘This paper addresses the problem of predicting population density leveraging cellular station data.As wireless communication devices are commonly used,cellular station data has become integral for estimating population figures and studying their movement,thereby implying significant contributions to urban planning.However,existing research grapples with issues pertinent to preprocessing base station data and the modeling of population prediction.To address this,we propose methodologies for preprocessing cellular station data to eliminate any irregular or redundant data.The preprocessing reveals a distinct cyclical characteristic and high-frequency variation in population shift.Further,we devise a multi-view enhancement model grounded on the Transformer(MVformer),targeting the improvement of the accuracy of extended time-series population predictions.Comparative experiments,conducted on the above-mentioned population dataset using four alternate Transformer-based models,indicate that our proposedMVformer model enhances prediction accuracy by approximately 30%for both univariate and multivariate time-series prediction assignments.The performance of this model in tasks pertaining to population prediction exhibits commendable results.
基金funded by the Major Humanities and Social Sciences Research Projects in Zhejiang higher education institutions,grant number 2023QN082,awarded to Cheng ZhaoThe National Natural Science Foundation of China also provided funding,grant number 61902349,awarded to Cheng Zhao.
文摘The present study examines the impact of short-term public opinion sentiment on the secondary market,with a focus on the potential for such sentiment to cause dramatic stock price fluctuations and increase investment risk.The quantification of investment sentiment indicators and the persistent analysis of their impact has been a complex and significant area of research.In this paper,a structured multi-head attention stock index prediction method based adaptive public opinion sentiment vector is proposed.The proposedmethod utilizes an innovative approach to transform numerous investor comments on social platforms over time into public opinion sentiment vectors expressing complex sentiments.It then analyzes the continuous impact of these vectors on the market through the use of aggregating techniques and public opinion data via a structured multi-head attention mechanism.The experimental results demonstrate that the public opinion sentiment vector can provide more comprehensive feedback on market sentiment than traditional sentiment polarity analysis.Furthermore,the multi-head attention mechanism is shown to improve prediction accuracy through attention convergence on each type of input information separately.Themean absolute percentage error(MAPE)of the proposedmethod is 0.463%,a reduction of 0.294% compared to the benchmark attention algorithm.Additionally,the market backtesting results indicate that the return was 24.560%,an improvement of 8.202% compared to the benchmark algorithm.These results suggest that themarket trading strategy based on thismethod has the potential to improve trading profits.
基金supported by the National Natural Science Foundation of China(81830115).
文摘Objective:To provide high-quality clinical evidence of the efficacy of Tibetan medicine Honghua Ruyi(HHRY)pills for endometriosis-associated dysmenorrhea.Methods:This study constitutes a multicenter,randomized,double-blind,placebo-controlled trial encompassing a three-menstrual cycle intervention followed by a three-menstrual cycle follow-up period.A total of 164 eligible females with endometriosis-associated dysmenorrhea were randomly divided into HHRY pills and placebo groups in a 1:1 ratio.The primary outcome included dysmenorrhea symptoms assessed using Visual Analog Scale(VAS)scores and quality of life,whereas the secondary outcome measures included the maximum VAS for non-menstrual pelvic pain,duration of pain episodes(in days),frequency and quantity of the consumption of ibuprofen sustained-release capsules(or other non-steroidal anti-inflammatory drugs),and days off work/study for staff/student due to dysmenorrhea,ovarian cyst,and/or pelvic nodule size.The safety was monitored throughout the treatment period.All the analyses were based on the intention-to-treat principle.For continuous outcomes,simple or multiple linear regressions were used to estimate the differences between the HHRY pills and placebo groups,with categorical data expressed as the number and percentage of occurrences.Differences were compared using the chi-square test or Fisher's exact test.The predefined analysis was adjusted for concomitant treatment,a variable considered to be associated with outcomes but unaffected by treatment allocation.Estimates of treatment effects were reported with 95%confidence intervals.Two-tailed P values≤.05 were considered statistically significant.Conclusion:Positive results from this trial,upon completion would provide robust evidence for the efficacy and safety of HHRY pills in treating dysmenorrhea in patients with endometriosis.
基金supported by the National Key Research and Development Program of China(2016YFA0601900)the National Natural Science Foundation of China(41401006)
文摘In recent years, there has been increasing research interests in differentiating the relative importance of climate factors and human activities in impacting vegetation dynamics. In this study, based on residual trend method, we used MOD13A3(MODIS vegetation index product), MCD12Q1(MODIS land cover product) and meteorological datasets to differentiate the relative importance of climate factors and human activities in impacting vegetation dynamics during 2000–2015 in the Otindag Sandy Land, northern China. Results show that during the study period(2000–2015), the overall vegetation condition had improved in the Otindag Sandy Land. The driving forces of vegetation dynamics differed spatially in the whole study area over the study period. The area with vegetation degradation solely resulted from human activities accounted for 8.23% of the study area, while the area with vegetation degradation resulted from others(including climate factors and combination of climate factors and human activities) occupied 1.53%. The area with vegetation recovery benefitted from human activities occurred over 26.02% of the study area; the area benefitted from climate factors accounted for 23.69%; and the area benefitted from both climate factors and human activities occupied 37.74%. All in all, impacts of climate factors and human activities on vegetation dynamics varied at the county/city/banner scales and locality-specific measures should be adopted to protect the environments.
基金supported by National Natural Science Foundation of China (Grant No. 70931004,Grant No. 70802043)
文摘Profile monitoring is used to check the stability of the quality of a product over time when the product quality is best represented by a function at each time point.However,most previous monitoring approaches have not considered that the argument values may vary from profile to profile,which is common in practice.A novel nonparametric control scheme based on profile error is proposed for monitoring nonlinear profiles with varied argument values.The proposed scheme uses the metrics of profile error as the statistics to construct the control charts.More details about the design of this nonparametric scheme are also discussed.The monitoring performance of the combined control scheme is compared with that of alternative nonparametric methods via simulation.Simulation studies show that the combined scheme is effective in detecting parameter error and is sensitive to small shifts in the process.In addition,due to the properties of the charting statistics,the out-of-control signal can provide diagnostic information for the users.Finally,the implementation steps of the proposed monitoring scheme are given and applied for monitoring the blade manufacturing process.With the application in blade manufacturing of aircraft engines,the proposed nonparametric control scheme is effective,interpretable,and easy to apply.
基金supported by the National Natural Science Foundation of China(7157212371172148)
文摘The systematic clustering analysis based weight determination methods are suitable for the experts of complex multiattribute large-group decision-making(CMALGDM) in intervalvalued intuitionistic fuzzy environment. However, these methods mainly have two shortcomings: they do not consider the consistency of the experts in each aggregation; the aggregation weights are often determined simply by the "majority principle", and neglect the quantity of information provided by the holistic aggregation,leading to decision biases. Hence, a double weight determination method for experts is proposed to solve these problems. As for the first shortcoming, a mathematical programming model is used to solve for the optimal expert weights within each aggregation,ensuring consistency in the overall preferences of the aggregations. As for the second shortcoming, we propose a modification of the aggregation weights based on the information entropy, which fully considers both the number of experts and the amount of information provided by the holistic aggregation. With the proposed method, the final expert weights are determined more rigorously and objectively. The feasibility of the proposed method is investigated through an illustrative example.
基金financed by the National Basic Research Program of China(2010CB951502)the National Natural Science Foundation of China(41101537,40930101,41201184 and 71203157)
文摘For the scientific management of farmland,it is significant to understand the spatio-temporal variability of soil organic matter and to study the influences of related factors.Using geostatistical theory,GIS spatial analysis,trend analysis and a Geographically Weighted Regression(GWR)model,this study analyzed the response of soil organic matter to climate and socio-economic factors in central Heilongjiang Province during the past 25 years.Second soil survey data of China for 1979-1985,2005 field sampling data,climate observations and socio-economic data for 1980-2005 were analyzed.First,soil organic matter in 2005 was spatially interpolated using the Co-Kriging method along with auxiliary data sets of soil type and pH.The spatio-temporal variability was then studied by comparison with the 1980s second soil census data.Next,the temporal trends in climate and socio-economic factors over the past 25 years were investigated.Finally,we examined the variation of the response of soil organic matter to climate and socio-economic factors using the GWR model spatially and temporally.The model showed that 53.82%area of the organic matter content remained constant and 29.39%has decreased during the past 25 years.The impact of precipitation on organic matter content is mainly negative,with increasing absolute values of the regression coefficient.The absolute value of regression coefficient of annual average temperature has decreased,and more areas are now under its negative effects.In addition,the areas of positive regression coefficient of annual sunshine hours have northward shifted,with the increasing absolute value of positive coefficient and decreasing absolute value of negative coefficient.The areas of positive regression coefficient of mechanized farming as a socio-economic factor have westward shifted,with the increasing absolute value of negative coefficient and decreasing absolute value of positive coefficient.The area of regions with the positive regression coefficient of irrigation has expanded.The regions with positive regression coefficient of fertilizer use have shrinked.The positive regression coefficient of mulch film consumption has significantly increased.The regression coefficient of pesticide consumption was mainly positive in the west of the study area,while it was negative to the east.Generally,GWR model is capable to investigate the influence of both climatic and socio-economic factors,avoided the insufficiency of other research based on the single perspective of climatic or socio-economic factors.Therefore,we can conclude that GWR model could provide methodological support for global change research and serve as basic reference for cultivated land quality improvement and agricultural decision making.
基金financial supports from National Natural Science Foundation of China(Grant Nos.4157152741801221+3 种基金4160161441701622)Sichuan Center for Rural Development Research Project(Grant No.01781912)Ministry of education humanities and social science research youth fund project(No.17YJC630136)
文摘The influence of labor migration on rural household land transfer has been hotly debated in academic circles, which focuses on whether part-time employment leads to land transfer. Using survey data on rural households in the Sichuan Province, and applying the theoretical framework of new economics of labor migration, this study explores the influences of labor migration on the direction and scale of land transfer from the perspective of rural household structure. The results indicate that: 1) the quantity of laborers has significant influence on the direction and scale of land transfer. The larger the on-farm labor variable(Labor), the lesser the possibility that land will be rented-out and the amount of land rented out will also be smaller. In addition, there is a greater probability that land will be rented-in and the amount of land rented-in will be greater. 2) The greater the ratio of off-farm laborers to rural household laborers(Off-farm) the greater the possibility that land will be rented-out. In addition the higher the ratio of on-farm laborers to the total household laborers(On-farm), the larger the possibility that land will be rented-in. Meanwhile, if the household has individuals at the age of 64 or older(Old) who are engaged in agriculture, there is a smaller possibility that land will be rentedout. 3) the ratio of part-time laborers to rural household laborers(Pluriactivity) have significant inverse U-shaped influences on the rent-in of land as well as the amount of land rented-in. The inflection points are 33.27% and 14.10%, respectively. Such findings confirm the significance of this study in better understanding the influence of labor migration on rural household land transfer.
基金Supported by National Natural Science Foundation of China(Grant No.51175222)Jilin Provincial Natural Science Foundation of China(Grant No.20150101025JC)High-end CNC machine tools and basic manufacturing equipment science and technology of major special projects(Grant No.2015ZX04003002)
文摘In order to rectify the problems that the component reliability model exhibits deviation, and the evaluation result is low due to the overlook of failure propagation in traditional reliability evaluation of machine center components, a new reliability evaluation method based on cascading failure analysis and the failure influenced degree assessment is proposed. A direct graph model of cascading failure among components is established according to cascading failure mechanism analysis and graph theory. The failure influenced degrees of the system components are assessed by the adjacency matrix and its transposition, combined with the Pagerank algorithm.Based on the comprehensive failure probability function and total probability formula, the inherent failure probability function is determined to realize the reliability evaluation of the system components. Finally, the method is applied to a machine center, it shows the following: 1)The reliability evaluation values of the proposed method are at least 2.5% higher than those of the traditional method; 2) The difference between the comprehensive and inherent reliability of the system component presents a positive correlation with the failure influenced degree ofthe system component, which provides a theoretical basis for reliability allocation of machine center system.
基金supported by the National Natural Science Foundation of China (No. 51522601)Chang Jiang Young Scholars Program of China (Q2016186)the Fok Ying Tong Education Foundation of China (No. 141055)
文摘In this study, the solar thermochemical reactor performance for CO_2 utilization into synthesis gas(H_2+ CO) based on CH_4 reforming process was investigated in the context of carbon capture and utilization(CCU) technologies. The P1 radiation heat transfer model is adopted to establish the heat and mass transfer model coupled with thermochemical reaction kinetics. The reactor thermal behavior with direct heat transfer between gaseous reactant and products evolution and the effects of different structural parameters were evaluated. It was found that the reactor has the potential to utilize by ～60% of CO_2 captured with 40% of CH_4 co-fed into syngas(72.9% of H_2 and 27.1% of CO) at 741.31 k W/mof incident radiation heat flux. However, the solar irradiance heat flux and temperature distribution were found to significantly affect the reactant species conversion efficiency and syngas production. The chemical reaction is mainly driven by the thermal energy and higher species conversion into syngas was observed when the temperature distribution at the inner cavity of the reactor was more uniform. Designed a solar thermochemical reactor able to volumetric store concentrated irradiance could highly improve CCU technologies for producing energy-rich chemicals. Besides, the mixture gas inlet velocity, operating pressure and CO_2/CH_4 feeding ratio were crucial to determining the efficiency of CO_2 utilization to solar fuels. Catalytic CO_2-reforming of CH_4 to chemical energy is a promising strategy for an efficient utilization of CO_2 as a renewable carbon source.
基金Project supported by the National Natural Science Foundation of China (Grant No. 70971094)the National Natural Science Youth Foundation of China (Grant No. 50908155)the Key Project of Tianjin Municipal Science and Technology Support Program,China (Grant No. 08ZCKFSF01000)
文摘This paper deals mainly with the influence of lane changing behaviours on the stability of two-lane traffic flow under a periodic boundary condition.Following the description of an optimal velocity model for two vehicle groups and the derivation of their stability conditions,the feedback signals,which involve information about vehicles from both lanes acting on the two-lane traffic system,are introduced into the optimal velocity model.The control signals play a role in alleviating the traffic jam only if the traffic state is in congestion,and their role will vanish if the traffic state is in the steady state.The numerical simulations show that lane changing behaviours can break the steady state of two-lane traffic flow and aggravate the traffic disturbance,but the control method would successfully suppress the traffic jam eventually,which implies that the conclusions obtained here have certain theoretical and practical significance.
基金Funded by the National Natural Science Foundation of China(51778582&51879235)the National Key R&D Plan(2017YFC0804809)
文摘In this paper, the cement paste and the mortar were tested using the PF-QNM technique. It is shown that the PF-QNM technique is very powerful to characterize the mechanical properties of micro-and nanostructures in the cement-based materials. It does not have strict requirements for test environment and it does not damage the surface of the material. High-resolution images can be obtained very easily, and they can be analyzed statistically. The test results show that PF-QNM analysis can test not only the mechanical properties of the cement paste, but also investigate the interfacial regions in the cement-based material, including the variation in the mechanical properties of interface regions and the extension of the interfacial regions. During the test, care must be taken to choose the size of test area;indeed, a test area too small is not representative but too large leads to lack of stability. The recommended side is a square with a length of in the range 10-30 μm.
基金supported by the Research Start Funds for Introducing High-level Talents of North China University of Water Resources and Electric Power
文摘This paper expresses the efficient outputs of decisionmaking unit(DMU) as the sum of "average outputs" forecasted by a GM(1,N) model and "increased outputs" which reflect the difficulty to realize efficient outputs.The increased outputs are solved by linear programming using data envelopment analysis efficiency theories,wherein a new sample is introduced whose inputs are equal to the budget in the issue No.n + 1 and outputs are forecasted by the GM(1,N) model.The shortcoming in the existing methods that the forecasted efficient outputs may be less than the possible actual outputs according to developing trends of input-output rate in the periods of pre-n is overcome.The new prediction method provides decision-makers with more decisionmaking information,and the initial conditions are easy to be given.
