Pitch is a complex mixture of polycyclic aromatic hydrocarbons and their non-metal derivatives that has a high carbon content.Using pitch as a precursor for carbon materials in alkali metal ion(Li^(+)/Na^(+)/K^(+))bat...Pitch is a complex mixture of polycyclic aromatic hydrocarbons and their non-metal derivatives that has a high carbon content.Using pitch as a precursor for carbon materials in alkali metal ion(Li^(+)/Na^(+)/K^(+))batteries has become of great interest.However,its direct pyrolysis often leads to microstructures with a high orientation and small interlayer spacing due to uncontrolled liquid-phase carbonization,resulting in subpar electrochemical performance.It is therefore important to control the microstructures of pitch-derived carbon materials in order to improve their electrochemical properties.We evaluate the latest progress in the development of these materials using various microstructural engineering approaches,highlighting their use in metal-ion batteries and supercapacitors.The advantages and limitations of pitch molecules and their carbon derivatives are outlined,together with strategies for their modification in order to improve their properties for specific applications.Future research possibilities for structure optimization,scalable production,and waste pitch recycling are also considered.展开更多
We consider a single server constant retrial queue,in which a state-dependent service policy is used to control the service rate.Customer arrival follows Poisson process,while service time and retrial time are exponen...We consider a single server constant retrial queue,in which a state-dependent service policy is used to control the service rate.Customer arrival follows Poisson process,while service time and retrial time are exponential distributions.Whenever the server is available,it admits the retrial customers into service based on a first-come first-served rule.The service rate adjusts in real-time based on the retrial queue length.An iterative algorithm is proposed to numerically solve the personal optimal problem in the fully observable scenario.Furthermore,we investigate the impact of parameters on the social optimal threshold.The effectiveness of the results is illustrated by two examples.展开更多
A new methodology for multi-step-ahead forecasting was proposed herein which combined the wavelet transform(WT), artificial neural network(ANN) and forecasting strategies based on the changing characteristics of avail...A new methodology for multi-step-ahead forecasting was proposed herein which combined the wavelet transform(WT), artificial neural network(ANN) and forecasting strategies based on the changing characteristics of available parking spaces(APS). First, several APS time series were decomposed and reconstituted by the wavelet transform. Then, using an artificial neural network, the following five strategies for multi-step-ahead time series forecasting were used to forecast the reconstructed time series: recursive strategy, direct strategy, multi-input multi-output(MIMO) strategy, DIRMO strategy(a combination of the direct and MIMO strategies), and newly proposed recursive multi-input multi-output(RECMO) strategy which is a combination of the recursive and MIMO strategies. Finally, integrating the predicted results with the reconstructed time series produced the final forecasted available parking spaces. Three findings appear to be consistently supported by the experimental results. First, applying the wavelet transform to multi-step ahead available parking spaces forecasting can effectively improve the forecasting accuracy. Second, the forecasting resulted from the DIRMO and RECMO strategies is more accurate than that of the other strategies. Finally, the RECMO strategy requires less model training time than the DIRMO strategy and consumes the least amount of training time among five forecasting strategies.展开更多
2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(HNIW), commonly called as CL-20, is a high energy and high density material of keen interest to both commercial and scientific worlds due to its greater insen...2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(HNIW), commonly called as CL-20, is a high energy and high density material of keen interest to both commercial and scientific worlds due to its greater insensitivity(reduced sensitivity) along with a positive high heat of formation, which is due to the azanitro groups attached to the skeleton of HNIW and its highly strained cage structure. It plays a remarkable role in modification and replacement of most of the propellant(gun and rocket) preparations. In this report we present the comparative strategies involved in the syntheses of HNIW with respect to economical and environmental aspects. Various methods reported in the literature on the purification of the crude HNIW(α-HNIW) to obtain ε-form of HNIW(high dense/more potential) are consolidated. Understanding of the structure, morphology, energetics, thermal behavior and their modification to meet the applicability(decreased impact sensitivity) determines the industrial application of HNIW. A compilation of the available literature on the aforementioned characteristic properties for obtaining a value added ε-HNIW is discussed here. This overview also reports the literature available on newer forms of HNIW including derivatives and cocrystals,which increase the performance of HNIW.展开更多
To avoid the old road of urban development with high consumption and high pollution,this paper took the houses in a village near Yinchuan(a typical city of Northwest China)as an exemplary project to explore the approp...To avoid the old road of urban development with high consumption and high pollution,this paper took the houses in a village near Yinchuan(a typical city of Northwest China)as an exemplary project to explore the appropriate strategies in the arid cold climate for the sustainable development in rural undeveloped areas Northwest China.Firstly,all houses were designed according to the principles of passive solar heating.Secondly,optimized biomass energy technologies such as biogas pit and straw gasification stove were utilized for cooking or heating.Last but not the least important,the ecological building materials such as earth,straw bale,fly ash were used to construct houses,which improves the indoor thermal comfort and meanwhile lowers the negative impact on the environment.Low costs,easy accessibility and habitants' inclination were taken into account in the process of design.展开更多
Display devices have significantly changed our daily life for decades,from the watches,television,to the laptop and smartphone.As the desire of advanced display device with high-resolution,long operation life and ligh...Display devices have significantly changed our daily life for decades,from the watches,television,to the laptop and smartphone.As the desire of advanced display device with high-resolution,long operation life and lightweight properties,several display techniques have been demonstrated.There are mainly four types of electronic display device:cathode ray tube(CRT),liquid-crystal display(LCD),organic light-emitting diode(OLED),and micro-LED.Due to the different working principles and device structures,each type of display device has its special characteristic properties.The performance of devices could be adjusted through the material selection or device design.With careful device structure regulation,not only the efficiency but also the stability would be improved.Herein,a brief review of innovative strategies towards the structure design is presented.展开更多
According to schema theory resulting from the psycholinguistic model of reading,comprehending a text is an interactive process between the reader background knowledge and the text. This article first views the psychol...According to schema theory resulting from the psycholinguistic model of reading,comprehending a text is an interactive process between the reader background knowledge and the text. This article first views the psycholinguistic model of reading and research in learning strategies, then discusses the application of socioaffective,cognitive, metacognitive learning strategies in Chinese EFL learners’ reading comprehension.展开更多
Vocabulary teaching is one aspect of language teaching that has not been given the attention it deserves until recent years. For a long period of time, vocabulary is simply taught in the way by asking students to stud...Vocabulary teaching is one aspect of language teaching that has not been given the attention it deserves until recent years. For a long period of time, vocabulary is simply taught in the way by asking students to study and memorize its meaning and spelling, its part of speech and its general function in a sentence. Thus, a student with a command of five thousand English vocabulary still finds it hard to adapt himself to the requirement of our demanding reading assignments, in particular, to the extensive reading task, which is more demanding due to its wide range of materials and large amount of vocabularies. According to Wilkins (1979: 111) "Without grammar very little can be conveyed, without vocabulary, nothing can be conveyed." Yet without a deeper understanding of how vocabulary is taught in the classroom and which methods of teaching are more effective for learners, the teaching of vocabulary may not achieve the desired effects. By researching the topic on vocabulary learning and instruction, this essay intends to bring the attention of both teachers and learners to the weaknesses of the traditional approach of teaching vocabulary and some different strategies in vocabulary instruction with the aim of improving the students’ reading comprehension.\;展开更多
Space-based optical(SBO)space surveillance has attracted widespread interest in the last two decades due to its considerable value in space situation awareness(SSA).SBO observation strategy,which is related to the per...Space-based optical(SBO)space surveillance has attracted widespread interest in the last two decades due to its considerable value in space situation awareness(SSA).SBO observation strategy,which is related to the performance of space surveillance,is the top-level design in SSA missions reviewed.The recognized real programs about SBO SAA proposed by the institutions in the U.S.,Canada,Europe,etc.,are summarized firstly,from which an insight of the development trend of SBO SAA can be obtained.According to the aim of the SBO SSA,the missions can be divided into general surveillance and space object tracking.Thus,there are two major categories for SBO SSA strategies.Existing general surveillance strategies for observing low earth orbit(LEO)objects and beyond-LEO objects are summarized and compared in terms of coverage rate,revisit time,visibility period,and image processing.Then,the SBO space object tracking strategies,which has experienced from tracking an object with a single satellite to tracking an object with multiple satellites cooperatively,are also summarized.Finally,this paper looks into the development trend in the future and points out several problems that challenges the SBO SSA.展开更多
Prediction has become more and more difficult in mineral exploration, especially in the mature exploration environment such as Tongling copper district. For enhancing predictive discovery of hidden ore deposits in suc...Prediction has become more and more difficult in mineral exploration, especially in the mature exploration environment such as Tongling copper district. For enhancing predictive discovery of hidden ore deposits in such mature environment, the key strategies which should be adopted include the innovation of the exploration models, application of the advanced exploration techniques and integration of multiple sets of information. The innovation of the exploration models should incorporate the new metallogenic concepts that are based on the geodynamic anatomization. The advanced techniques applied in the mature exploration environment should aim at the speciality and complexity of the geological setting and working environments. The information synthesis is to integrate multiple sets of data for giving a more credible and visual prospectivity map by using the geographic imformation system(GIS) and several mathematical methods, such as weight of evidence and fuzzy logic, which can extract useful information from every set of data as much as possible. Guided by these strategies, a predictive exploration in Fenghuangshan ore field of Tongling copper district was implemented, and a hidden ore deposit was discovered.展开更多
This paper simulated the optimal refrigerant charge inventory of a refrigeration system in air-conditioning operation and heat-pump operation respectively,and studied the refrigerant control strategies in this system....This paper simulated the optimal refrigerant charge inventory of a refrigeration system in air-conditioning operation and heat-pump operation respectively,and studied the refrigerant control strategies in this system.The void fraction in two-phase fluid region was calculated by Harms model.And based on distributed parameter model and Harms model,the refrigerant charge inventory in condenser and evaporator were calculated and analyzed in air-conditioning conditions and heat-pump conditions,respectively.The calculating results of different refrigerant mass between refrigeration and heating conditions indicate that the optimal refrigerant charge inventory in heat-pump conditions is lower than that in air-conditioning conditions.To avoid the decrease of COP due to the surplus refrigerant in heating conditions,we introduced the liquid reservoir control method and associate capillary control method.Both of them could increase the heating capacity of the air-source heat pump.The difference of optimal refrigerant charge inventory in air-conditioning and heat-pump system can be controlled by the liquid reservoir or the associate capillary.展开更多
With the development of psycho-linguistics in the past twenty years or so, listening comprehension strategy has become an increasingly important aspect of research on Second Language Acquisition and Instruction. Altho...With the development of psycho-linguistics in the past twenty years or so, listening comprehension strategy has become an increasingly important aspect of research on Second Language Acquisition and Instruction. Although much has been done by researchers like O’Malley, Bacon, Richard, there is still some argument about what are listening comprehension strategies, how they can be classified, and what, as well as how they can be taught in class. This article is intended to contribute some ideas to these controversial fields of research on Listening Comprehension Strategy.\;For the theoretical aspect, the writers of this article venture a system of strategies, which is based on the well-established cognitive classification of learning strategies, and at the same time includes those strategies characteristic of listening comprehension.\;For the practical aspect, in order to find out on what strategies students need more training, a survey has been conducted on how students (first year and second year non-English majors) make use of listening comprehension strategies in the process of listening comprehension. By analyzing the students’ response to the survey, the writers of this article find that both first year and second year students are weak at using listening comprehension strategies. Of the 25 strategies, only 8 strategies are within the students’ command. This is explained as a result of lack of training in class. The writers appeal for more strategy-consciousness on the part of English teachers. The writers also find that the most serious problem in strategy using lies in discourse strategies, the difficulty of which often goes hand in hand with that in reading comprehension. And the training of discourse strategies is predicted by the writers of this article to be the most difficult part of listening class.\;展开更多
The booming live-streaming commerce has significantly changed the traditional e-commerce model,thus attracting much attention from both industry and academia.In recent years,an increasing number of scholars have appli...The booming live-streaming commerce has significantly changed the traditional e-commerce model,thus attracting much attention from both industry and academia.In recent years,an increasing number of scholars have applied analytical models to explore live-streaming strategies for firms in different scenarios.However,the previous literature mainly considers monopolists,while in the real world,competition is not rare.To fill this gap between the literature and practical observations,this paper applies a game theoretical model to study live-streaming adoption and pricing strategy for firms under competitive environments.The results show that,for competitive firms,the equilibrium strategy depends on the relation between the commission rate and the intensity of the market expansion effect.Additionally,compared to the case in which no firm adopts live-streaming,competitive firms do not always benefit from the adoption of live-streaming selling.The paper also shows that competition plays a negative role in inducing a firm to adopt live-streaming.展开更多
Rice is the main food of Sierra Leoneans and an important source of employment and income for rural communities. According to the West African Rice Development Association report, annual consumption of rice is amongst...Rice is the main food of Sierra Leoneans and an important source of employment and income for rural communities. According to the West African Rice Development Association report, annual consumption of rice is amongst the highest in SubSaharan Africa（SSA）, 104 kg. Mainly, small scale farmers who are resource poor on both the upland and various lowlands grow rice. Sierra Leone has not been able to produce enough rice to meet its local consumption demand for a very long time now. 530 000 MT of milled rice is the required consumption need of the Sierra Leonean population per annum. In 2007, national paddy rice production was projected at 638 000 MT. The level of rice self-sufficiency rose from 50.57% in 2002 to 62.15% in 2006 and then to 63.49% in 2007. The remainder must be imported at increasingly expensive prices in the current situation of high food prices, which includes rice. The price of rice has seen a steady increase in the entire country. What most affected by this, is the low-income urban and peri-urban households. The promotion of domestic rice production is therefore a key element in the strategies for improving rice self-sufficiency, stimulating economic growth and increasing rural income. Therefore, supporting rice production programme is the only solution to pull the country out of the worsening rice situation and maintain the present trend in rice self-sufficiency. Therefore, having an understanding of the strategic interventions in rice production in Sierra Leone is an important ingredient in the promotion and attainment of rice self-sufficiency.展开更多
Climate change is one of the most significant environment issues in the whole world today. And it is one of the most complex challenges of the humanities faced in the 21st century. Climate Change is impacted on our gl...Climate change is one of the most significant environment issues in the whole world today. And it is one of the most complex challenges of the humanities faced in the 21st century. Climate Change is impacted on our global; nobody can avoid the influence of climate change. The local adaptation strategies on climate change are very important to contribute the mitigation and poverty stricken situation, both in China and in the world. We chose a typical China＇s province as a case to analyze the impact of climate change on the region （such as agricultural, natural ecosystems, water resources, as well as local people healthy condition）, and how the local government and local residences face the impact of the climate change influence, and summarized several strategies on climate change of the area in a sustainable development way.展开更多
Natural grassland in the West of Northeastern China is located in 40°0′- 43°5′N latitude and 117°0′ -127°5′Elongitude. It lies in the Liao River Valley, the Songhua River Valley and Nen River V...Natural grassland in the West of Northeastern China is located in 40°0′- 43°5′N latitude and 117°0′ -127°5′Elongitude. It lies in the Liao River Valley, the Songhua River Valley and Nen River Valley. About 130 years ago, this region had rich natural grassland resources, was numerically 26.67 millions in hectare of grasslands. Since the last stage of Qing Dynasty, the grassland has been destroyed seriously in 3 times. Up to now, this region only preserved about 2 millions in hectare of the grasslands. In addition, 3.33 millions in hectare of the grasslands have changed from primary grassland to desertification, salinizatio-nalkalinization and degeneration grasslands in the form of patches of bare soil(their simple form of a name is'3 kinds of degeneration grasslands'). This paper indicaed that in any period both grasslands destruction and its restoration were relevant to economic changes and economic systems, particularly to market econmy in that time. The following agricultural economic-technological strategies have been applied to transform of retrogressive grasslands: ① to return reclaimed grassland as farmland to primary grassland in order to greatly increase-economic ecological benefits; ② to close desertification, salinizationalkalinization and degradation grasslands in the form of patches of bare soil; ③to develop grassland-agriculture for establishment of stable production bases of concentrated feed crops and coarse herbage crops.展开更多
In the realm of aerial warfare,the protection of Unmanned Aerial Vehicles(UAVs) against adversarial threats is crucial.In order to balance the impact of response delays and the demand for onboard applications,this pap...In the realm of aerial warfare,the protection of Unmanned Aerial Vehicles(UAVs) against adversarial threats is crucial.In order to balance the impact of response delays and the demand for onboard applications,this paper derives three analytical game strategies for the active defense of UAVs from differential game theory,accommodating the first-order dynamic delays.The targeted UAV executes evasive maneuvers and launches a defending missile to intercept the attacking missile,which constitutes a UAVMissile-Defender(UMD) three-body game problem.We explore two distinct operational paradigms:the first involves the UAV and the defender working collaboratively to intercept the incoming threat,while the second prioritizes UAV self-preservation,with independent maneuvering away from potentially sacrificial engagements.Starting with model linearization and order reduction,the Collaborative Interception Strategy(CIS) is first derived via a linear quadratic differential game formulation.Building upon CIS,we further explore two distinct strategies:the Informed Defender Interception Strategy(IDIS),which utilizes UAV maneuvering information,and the Unassisted Defender Interception Strategy(UDIS),which does not rely on UAV maneuvering information.Additionally,we investigate the conditions for the existence of saddle point solutions and their relationship with vehicle maneuverability and response agility.The simulations demonstrate the effectiveness and advantages of the proposed strategies.展开更多
Diversity indexes of current forestry view, such as dominance degree, fragmentation degree and overcast degree, were evaluated by the software ARCVIEWGIS. And developing strategies to improve diversity were put forwar...Diversity indexes of current forestry view, such as dominance degree, fragmentation degree and overcast degree, were evaluated by the software ARCVIEWGIS. And developing strategies to improve diversity were put forward in this paper, that is, combining with the items of forestry tour and enhancing scientific management, and choosing typical trees to change forestry structure on the basis of general conditions of dominance degree, fragmentation degree and overcast degree.展开更多
近日,东南大学计算机与科学工程学院白如帆在人工智能领域国际期刊《Artificial Intelligence》(AIJ,CCF A)上发表题为“On the Computation of Mixed Strategies for Security Games with General Defending Requirements”的论文,介...近日,东南大学计算机与科学工程学院白如帆在人工智能领域国际期刊《Artificial Intelligence》(AIJ,CCF A)上发表题为“On the Computation of Mixed Strategies for Security Games with General Defending Requirements”的论文,介绍该团队在智能体安全博弈领域内的最新研究成果,白如帆老师为论文唯一第一作者,这也是东南大学第二次以第一、通信单位身份在该期刊发表论文。展开更多
文摘Pitch is a complex mixture of polycyclic aromatic hydrocarbons and their non-metal derivatives that has a high carbon content.Using pitch as a precursor for carbon materials in alkali metal ion(Li^(+)/Na^(+)/K^(+))batteries has become of great interest.However,its direct pyrolysis often leads to microstructures with a high orientation and small interlayer spacing due to uncontrolled liquid-phase carbonization,resulting in subpar electrochemical performance.It is therefore important to control the microstructures of pitch-derived carbon materials in order to improve their electrochemical properties.We evaluate the latest progress in the development of these materials using various microstructural engineering approaches,highlighting their use in metal-ion batteries and supercapacitors.The advantages and limitations of pitch molecules and their carbon derivatives are outlined,together with strategies for their modification in order to improve their properties for specific applications.Future research possibilities for structure optimization,scalable production,and waste pitch recycling are also considered.
基金supported by the National Natural Science Foundation of China(Grant No.11971486)。
文摘We consider a single server constant retrial queue,in which a state-dependent service policy is used to control the service rate.Customer arrival follows Poisson process,while service time and retrial time are exponential distributions.Whenever the server is available,it admits the retrial customers into service based on a first-come first-served rule.The service rate adjusts in real-time based on the retrial queue length.An iterative algorithm is proposed to numerically solve the personal optimal problem in the fully observable scenario.Furthermore,we investigate the impact of parameters on the social optimal threshold.The effectiveness of the results is illustrated by two examples.
基金Project(51561135003)supported by the International Cooperation and Exchange of the National Natural Science Foundation of ChinaProject(51338003)supported by the Key Project of National Natural Science Foundation of China
文摘A new methodology for multi-step-ahead forecasting was proposed herein which combined the wavelet transform(WT), artificial neural network(ANN) and forecasting strategies based on the changing characteristics of available parking spaces(APS). First, several APS time series were decomposed and reconstituted by the wavelet transform. Then, using an artificial neural network, the following five strategies for multi-step-ahead time series forecasting were used to forecast the reconstructed time series: recursive strategy, direct strategy, multi-input multi-output(MIMO) strategy, DIRMO strategy(a combination of the direct and MIMO strategies), and newly proposed recursive multi-input multi-output(RECMO) strategy which is a combination of the recursive and MIMO strategies. Finally, integrating the predicted results with the reconstructed time series produced the final forecasted available parking spaces. Three findings appear to be consistently supported by the experimental results. First, applying the wavelet transform to multi-step ahead available parking spaces forecasting can effectively improve the forecasting accuracy. Second, the forecasting resulted from the DIRMO and RECMO strategies is more accurate than that of the other strategies. Finally, the RECMO strategy requires less model training time than the DIRMO strategy and consumes the least amount of training time among five forecasting strategies.
基金financial assistance under the sponsored project "Novel materials for high energy reactions" (H/A: 4254) to Gulbarga University, Kalaburagi, India
文摘2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(HNIW), commonly called as CL-20, is a high energy and high density material of keen interest to both commercial and scientific worlds due to its greater insensitivity(reduced sensitivity) along with a positive high heat of formation, which is due to the azanitro groups attached to the skeleton of HNIW and its highly strained cage structure. It plays a remarkable role in modification and replacement of most of the propellant(gun and rocket) preparations. In this report we present the comparative strategies involved in the syntheses of HNIW with respect to economical and environmental aspects. Various methods reported in the literature on the purification of the crude HNIW(α-HNIW) to obtain ε-form of HNIW(high dense/more potential) are consolidated. Understanding of the structure, morphology, energetics, thermal behavior and their modification to meet the applicability(decreased impact sensitivity) determines the industrial application of HNIW. A compilation of the available literature on the aforementioned characteristic properties for obtaining a value added ε-HNIW is discussed here. This overview also reports the literature available on newer forms of HNIW including derivatives and cocrystals,which increase the performance of HNIW.
基金Supported by National Key Technology R&D Programin the 11th Five Year Plan of China(2006BAJ04A18)
文摘To avoid the old road of urban development with high consumption and high pollution,this paper took the houses in a village near Yinchuan(a typical city of Northwest China)as an exemplary project to explore the appropriate strategies in the arid cold climate for the sustainable development in rural undeveloped areas Northwest China.Firstly,all houses were designed according to the principles of passive solar heating.Secondly,optimized biomass energy technologies such as biogas pit and straw gasification stove were utilized for cooking or heating.Last but not the least important,the ecological building materials such as earth,straw bale,fly ash were used to construct houses,which improves the indoor thermal comfort and meanwhile lowers the negative impact on the environment.Low costs,easy accessibility and habitants' inclination were taken into account in the process of design.
基金Projects(71572028,71872027)supported by the National Natural Science Foundation of China。
文摘Display devices have significantly changed our daily life for decades,from the watches,television,to the laptop and smartphone.As the desire of advanced display device with high-resolution,long operation life and lightweight properties,several display techniques have been demonstrated.There are mainly four types of electronic display device:cathode ray tube(CRT),liquid-crystal display(LCD),organic light-emitting diode(OLED),and micro-LED.Due to the different working principles and device structures,each type of display device has its special characteristic properties.The performance of devices could be adjusted through the material selection or device design.With careful device structure regulation,not only the efficiency but also the stability would be improved.Herein,a brief review of innovative strategies towards the structure design is presented.
文摘According to schema theory resulting from the psycholinguistic model of reading,comprehending a text is an interactive process between the reader background knowledge and the text. This article first views the psycholinguistic model of reading and research in learning strategies, then discusses the application of socioaffective,cognitive, metacognitive learning strategies in Chinese EFL learners’ reading comprehension.
文摘Vocabulary teaching is one aspect of language teaching that has not been given the attention it deserves until recent years. For a long period of time, vocabulary is simply taught in the way by asking students to study and memorize its meaning and spelling, its part of speech and its general function in a sentence. Thus, a student with a command of five thousand English vocabulary still finds it hard to adapt himself to the requirement of our demanding reading assignments, in particular, to the extensive reading task, which is more demanding due to its wide range of materials and large amount of vocabularies. According to Wilkins (1979: 111) "Without grammar very little can be conveyed, without vocabulary, nothing can be conveyed." Yet without a deeper understanding of how vocabulary is taught in the classroom and which methods of teaching are more effective for learners, the teaching of vocabulary may not achieve the desired effects. By researching the topic on vocabulary learning and instruction, this essay intends to bring the attention of both teachers and learners to the weaknesses of the traditional approach of teaching vocabulary and some different strategies in vocabulary instruction with the aim of improving the students’ reading comprehension.\;
基金This work was supported by the National Natural Science Foundation of China(61690210,61690213).
文摘Space-based optical(SBO)space surveillance has attracted widespread interest in the last two decades due to its considerable value in space situation awareness(SSA).SBO observation strategy,which is related to the performance of space surveillance,is the top-level design in SSA missions reviewed.The recognized real programs about SBO SAA proposed by the institutions in the U.S.,Canada,Europe,etc.,are summarized firstly,from which an insight of the development trend of SBO SAA can be obtained.According to the aim of the SBO SSA,the missions can be divided into general surveillance and space object tracking.Thus,there are two major categories for SBO SSA strategies.Existing general surveillance strategies for observing low earth orbit(LEO)objects and beyond-LEO objects are summarized and compared in terms of coverage rate,revisit time,visibility period,and image processing.Then,the SBO space object tracking strategies,which has experienced from tracking an object with a single satellite to tracking an object with multiple satellites cooperatively,are also summarized.Finally,this paper looks into the development trend in the future and points out several problems that challenges the SBO SSA.
基金Project(2001CB409809) supported by the National Key Foundmental Research and Development Program of Chinaproject(1042610) supported by the Key Program of the Education Ministry of China
文摘Prediction has become more and more difficult in mineral exploration, especially in the mature exploration environment such as Tongling copper district. For enhancing predictive discovery of hidden ore deposits in such mature environment, the key strategies which should be adopted include the innovation of the exploration models, application of the advanced exploration techniques and integration of multiple sets of information. The innovation of the exploration models should incorporate the new metallogenic concepts that are based on the geodynamic anatomization. The advanced techniques applied in the mature exploration environment should aim at the speciality and complexity of the geological setting and working environments. The information synthesis is to integrate multiple sets of data for giving a more credible and visual prospectivity map by using the geographic imformation system(GIS) and several mathematical methods, such as weight of evidence and fuzzy logic, which can extract useful information from every set of data as much as possible. Guided by these strategies, a predictive exploration in Fenghuangshan ore field of Tongling copper district was implemented, and a hidden ore deposit was discovered.
基金Supported by Hubei Provincial Natural Science Foundation(2008CDB363)
文摘This paper simulated the optimal refrigerant charge inventory of a refrigeration system in air-conditioning operation and heat-pump operation respectively,and studied the refrigerant control strategies in this system.The void fraction in two-phase fluid region was calculated by Harms model.And based on distributed parameter model and Harms model,the refrigerant charge inventory in condenser and evaporator were calculated and analyzed in air-conditioning conditions and heat-pump conditions,respectively.The calculating results of different refrigerant mass between refrigeration and heating conditions indicate that the optimal refrigerant charge inventory in heat-pump conditions is lower than that in air-conditioning conditions.To avoid the decrease of COP due to the surplus refrigerant in heating conditions,we introduced the liquid reservoir control method and associate capillary control method.Both of them could increase the heating capacity of the air-source heat pump.The difference of optimal refrigerant charge inventory in air-conditioning and heat-pump system can be controlled by the liquid reservoir or the associate capillary.
文摘With the development of psycho-linguistics in the past twenty years or so, listening comprehension strategy has become an increasingly important aspect of research on Second Language Acquisition and Instruction. Although much has been done by researchers like O’Malley, Bacon, Richard, there is still some argument about what are listening comprehension strategies, how they can be classified, and what, as well as how they can be taught in class. This article is intended to contribute some ideas to these controversial fields of research on Listening Comprehension Strategy.\;For the theoretical aspect, the writers of this article venture a system of strategies, which is based on the well-established cognitive classification of learning strategies, and at the same time includes those strategies characteristic of listening comprehension.\;For the practical aspect, in order to find out on what strategies students need more training, a survey has been conducted on how students (first year and second year non-English majors) make use of listening comprehension strategies in the process of listening comprehension. By analyzing the students’ response to the survey, the writers of this article find that both first year and second year students are weak at using listening comprehension strategies. Of the 25 strategies, only 8 strategies are within the students’ command. This is explained as a result of lack of training in class. The writers appeal for more strategy-consciousness on the part of English teachers. The writers also find that the most serious problem in strategy using lies in discourse strategies, the difficulty of which often goes hand in hand with that in reading comprehension. And the training of discourse strategies is predicted by the writers of this article to be the most difficult part of listening class.\;
基金supported by the National Natural Science Foundation of China(72171219,72201264,71921001,71801206,71971203)the Fundamental Research Funds for the Central Universities(WK2040000027)+1 种基金the New Liberal Arts Fund of USTC(FSSF-A-230104)the Four Batch Talent Programs of China.
文摘The booming live-streaming commerce has significantly changed the traditional e-commerce model,thus attracting much attention from both industry and academia.In recent years,an increasing number of scholars have applied analytical models to explore live-streaming strategies for firms in different scenarios.However,the previous literature mainly considers monopolists,while in the real world,competition is not rare.To fill this gap between the literature and practical observations,this paper applies a game theoretical model to study live-streaming adoption and pricing strategy for firms under competitive environments.The results show that,for competitive firms,the equilibrium strategy depends on the relation between the commission rate and the intensity of the market expansion effect.Additionally,compared to the case in which no firm adopts live-streaming,competitive firms do not always benefit from the adoption of live-streaming selling.The paper also shows that competition plays a negative role in inducing a firm to adopt live-streaming.
文摘Rice is the main food of Sierra Leoneans and an important source of employment and income for rural communities. According to the West African Rice Development Association report, annual consumption of rice is amongst the highest in SubSaharan Africa（SSA）, 104 kg. Mainly, small scale farmers who are resource poor on both the upland and various lowlands grow rice. Sierra Leone has not been able to produce enough rice to meet its local consumption demand for a very long time now. 530 000 MT of milled rice is the required consumption need of the Sierra Leonean population per annum. In 2007, national paddy rice production was projected at 638 000 MT. The level of rice self-sufficiency rose from 50.57% in 2002 to 62.15% in 2006 and then to 63.49% in 2007. The remainder must be imported at increasingly expensive prices in the current situation of high food prices, which includes rice. The price of rice has seen a steady increase in the entire country. What most affected by this, is the low-income urban and peri-urban households. The promotion of domestic rice production is therefore a key element in the strategies for improving rice self-sufficiency, stimulating economic growth and increasing rural income. Therefore, supporting rice production programme is the only solution to pull the country out of the worsening rice situation and maintain the present trend in rice self-sufficiency. Therefore, having an understanding of the strategic interventions in rice production in Sierra Leone is an important ingredient in the promotion and attainment of rice self-sufficiency.
文摘Climate change is one of the most significant environment issues in the whole world today. And it is one of the most complex challenges of the humanities faced in the 21st century. Climate Change is impacted on our global; nobody can avoid the influence of climate change. The local adaptation strategies on climate change are very important to contribute the mitigation and poverty stricken situation, both in China and in the world. We chose a typical China＇s province as a case to analyze the impact of climate change on the region （such as agricultural, natural ecosystems, water resources, as well as local people healthy condition）, and how the local government and local residences face the impact of the climate change influence, and summarized several strategies on climate change of the area in a sustainable development way.
文摘Natural grassland in the West of Northeastern China is located in 40°0′- 43°5′N latitude and 117°0′ -127°5′Elongitude. It lies in the Liao River Valley, the Songhua River Valley and Nen River Valley. About 130 years ago, this region had rich natural grassland resources, was numerically 26.67 millions in hectare of grasslands. Since the last stage of Qing Dynasty, the grassland has been destroyed seriously in 3 times. Up to now, this region only preserved about 2 millions in hectare of the grasslands. In addition, 3.33 millions in hectare of the grasslands have changed from primary grassland to desertification, salinizatio-nalkalinization and degeneration grasslands in the form of patches of bare soil(their simple form of a name is'3 kinds of degeneration grasslands'). This paper indicaed that in any period both grasslands destruction and its restoration were relevant to economic changes and economic systems, particularly to market econmy in that time. The following agricultural economic-technological strategies have been applied to transform of retrogressive grasslands: ① to return reclaimed grassland as farmland to primary grassland in order to greatly increase-economic ecological benefits; ② to close desertification, salinizationalkalinization and degradation grasslands in the form of patches of bare soil; ③to develop grassland-agriculture for establishment of stable production bases of concentrated feed crops and coarse herbage crops.
基金supported by the China Postdoctoral Science Foundation (Grant No.2021M700321)the Fundamental Research Funds for the Central Universities (Grant No.YWF-23-Q1041)。
文摘In the realm of aerial warfare,the protection of Unmanned Aerial Vehicles(UAVs) against adversarial threats is crucial.In order to balance the impact of response delays and the demand for onboard applications,this paper derives three analytical game strategies for the active defense of UAVs from differential game theory,accommodating the first-order dynamic delays.The targeted UAV executes evasive maneuvers and launches a defending missile to intercept the attacking missile,which constitutes a UAVMissile-Defender(UMD) three-body game problem.We explore two distinct operational paradigms:the first involves the UAV and the defender working collaboratively to intercept the incoming threat,while the second prioritizes UAV self-preservation,with independent maneuvering away from potentially sacrificial engagements.Starting with model linearization and order reduction,the Collaborative Interception Strategy(CIS) is first derived via a linear quadratic differential game formulation.Building upon CIS,we further explore two distinct strategies:the Informed Defender Interception Strategy(IDIS),which utilizes UAV maneuvering information,and the Unassisted Defender Interception Strategy(UDIS),which does not rely on UAV maneuvering information.Additionally,we investigate the conditions for the existence of saddle point solutions and their relationship with vehicle maneuverability and response agility.The simulations demonstrate the effectiveness and advantages of the proposed strategies.
文摘Diversity indexes of current forestry view, such as dominance degree, fragmentation degree and overcast degree, were evaluated by the software ARCVIEWGIS. And developing strategies to improve diversity were put forward in this paper, that is, combining with the items of forestry tour and enhancing scientific management, and choosing typical trees to change forestry structure on the basis of general conditions of dominance degree, fragmentation degree and overcast degree.
文摘近日,东南大学计算机与科学工程学院白如帆在人工智能领域国际期刊《Artificial Intelligence》(AIJ,CCF A)上发表题为“On the Computation of Mixed Strategies for Security Games with General Defending Requirements”的论文,介绍该团队在智能体安全博弈领域内的最新研究成果,白如帆老师为论文唯一第一作者,这也是东南大学第二次以第一、通信单位身份在该期刊发表论文。
