Past studies reveal the prevalence of anxiety,coupled with low motivation and disengagement among students in English-medium instruction(EMI)programs.Given the detrimental impact these negative emotions can have on le...Past studies reveal the prevalence of anxiety,coupled with low motivation and disengagement among students in English-medium instruction(EMI)programs.Given the detrimental impact these negative emotions can have on learning outcomes,it is imperative that teachers establish positive emotional rapport with their students.This study explores how experienced and highly rated EMI lecturers at a Chinese university’s overseas campus use communication strategies to build rapport with their students during interactive academic activities.It identifies the strategies used by these lecturers and examines how the strategies facilitate the teaching-learning process.The data,consisting of 10 hours of tutorials and 10 hours of supervisor-student supervision meetings,is analyzed using an adapted Conversation Analysis(CA)approach.The analysis reveals three types of communication strategies(CSs)frequently used by lecturers:back-channeling,codeswitching,and co-creation of messages.By employing these strategies,the lecturers established a strong rapport with the students,which created an encouraging and supportive learning environment.Consequently,this positive atmosphere facilitated students’learning of content knowledge through English.The findings of this study have implications for the training of lecturers who encounter difficulties in establishing rapport with multilingual students in the EMI setting.展开更多
Photocatalytic splitting of water over p-type semiconductors is a promising strategy for production of hydrogen.However,the determination of rate law is rarely reported.To this purpose,copper oxide(CuO)is selected as ...Photocatalytic splitting of water over p-type semiconductors is a promising strategy for production of hydrogen.However,the determination of rate law is rarely reported.To this purpose,copper oxide(CuO)is selected as a model photocathode in this study,and the photogenerated surface charge density,interfacial charge transfer rate constant and their relation to the water reduction rate(in terms of photocurrent)were investigated by a combination of(photo)electrochemical techniques.The results showed that the charge transfer rate constant is exponential-dependent on the surface charge density,and that the photocurrent equals to the product of the charge transfer rate constant and surface charge density.The reaction is first-order in terms of surface charge density.Such an unconventional rate law contrasts with the reports in literature.The charge density-dependent rate constant results from the Fermi level pinning(i.e.,Galvani potential is the main driving force for the reaction)due to accumulation of charge in the surface states and/or Frumkin behavior(i.e.,chemical potential is the main driving force).This study,therefore,may be helpful for further investigation on the mechanism of hydrogen evolution over a CuO photocathode and for designing more efficient CuO-based photocatalysts.展开更多
For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological...For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological index(RSEI)was calculated for the Lijiang River Basin in Guangxi Zhuang Autonomous Region for 1991,2001,2011,and 2021.Spatial autocorrelation analysis was employed to investigate spatiotemporal variations in the ecological environmental quality of the Lijiang River Basin.Furthermore,geographic detectors were used to quantitatively analyze influencing factors and their interaction effects on ecological environmental quality.The results verified that:1)From 1991 to 2021,the ecological environmental quality of the Lijiang River Basin demonstrated significant improvement.The area with good and excellent ecological environmental quality in proportion increased by 19.69%(3406.57 km^(2)),while the area with fair and poor ecological environmental quality in proportion decreased by 10.76%(1860.36 km^(2)).2)Spatially,the ecological environmental quality of the Lijiang River Basin exhibited a pattern of low quality in the central region and high quality in the periphery.Specifically,poor ecological environmental quality characterized the Guilin urban area,Pingle County,and Lingchuan County.3)From 1991 to 2021,a significant positive spatial correlation was observed in ecological environmental quality of the Lijiang River Basin.Areas with high-high agglomeration were predominantly forests and grasslands,indicating good ecological environmental quality,whereas areas with low-low agglomeration were dominated by cultivated land and construction land,indicating poor ecological environmental quality.4)Annual average precipitation and temperature exerted the most significant influence on the ecological environmental quality of the basin,and their interactions with other factors had the great influence.This study aimed to enhance understanding of the evolution of the ecological environment in the Lijiang River Basin of Guangxi Zhuang Autonomous Region and provide scientific guidance for decision-making and management related to ecology in the region.展开更多
Thermodynamic and kinetic aspects of Sn nucleation and growth processes onto a glassy carbon electrode from SnCl2·2H2O dissolved in ethylene glycol solutions were studied.Typical reduction and oxidation peaks obs...Thermodynamic and kinetic aspects of Sn nucleation and growth processes onto a glassy carbon electrode from SnCl2·2H2O dissolved in ethylene glycol solutions were studied.Typical reduction and oxidation peaks observed in voltammograms have demonstrated the capability of ethylene glycol solutions to electrodeposit Sn.The temperature-dependence of diffusion coefficient values derived from potentiodynamic and potentiostatic studies helped to determine and validate estimations of the activation energy for Sn(II)bulk diffusion.Chronoamperometric results have identified that,the suitable model to describe the early stage of Sn electrodeposition could be composed of Sn three-dimensional nucleation and diffusion-controlled growth and water reduction contributions,which was duly validated by theoretical and experimental approaches.From the model,typical kinetic parameters such as the nucleation frequency of Sn(A),number density of Sn nuclei(N_(0)),and diffusion coefficient of Sn(II)ions(D),were determined.The presence of Sn nuclei with excellent quality and their structures were verified using SEM,EDX,and XRD techniques.展开更多
Research of autonomous manufacturing systems is motivated both by the new technical possibilities of cyber-physical systems and by the practical needs of the industry.Autonomous operation in semi-structured industrial...Research of autonomous manufacturing systems is motivated both by the new technical possibilities of cyber-physical systems and by the practical needs of the industry.Autonomous operation in semi-structured industrial environments can now be supported by advanced sensor technologies,digital twins,artificial intelligence and novel communication techniques.These enable real-time monitoring of production processes,situation recognition and prediction,automated and adaptive(re)planning,teamwork and performance improvement by learning.This paper summarizes the main requirements towards autonomous industrial robotics and suggests a generic workflow for realizing such systems.Application case studies will be presented from recent practice at HUN-REN SZTAKI in a broad range of domains such as assembly,welding,grinding,picking and placing,and machining.The various solutions have in common that they use a generic digital twin concept as their core.After making general recommendations for realizing autonomous robotic solutions in the industry,open issues for future research will be discussed.展开更多
The effect of Si on the growth kinetics of intermetallic compounds during the reaction of solid iron and molten aluminum was investigated with a scanning electron microscope coupled with an energy dispersive X-ray spe...The effect of Si on the growth kinetics of intermetallic compounds during the reaction of solid iron and molten aluminum was investigated with a scanning electron microscope coupled with an energy dispersive X-ray spectroscope, and hot-dip aluminized experiments. The results show that the intermetallic layer is composed of major Fe2Al5 and minor FeAl3. The Al-Fe-Si ternary phase, rl/rg, is formed in the Fe2Al5 layer. The tongue-like morphology of the Fe2Als layer becomes less distinct and disappears finally as the content of Si in aluminum bath increases. Si in the bath improves the prohibiting ability to the growth of Fe2Als and FeAl3. When the contents of Si are 0, 0.5%, 1.0%, 1.5%, 2.0% and 3.0%, the activation energies of Fe2Al5 are evaluated to be 207, 186, 169, 168, 167 and 172 kJ/mol, respectively. The reduction of the activation energy might result from the lattice distortion caused by Si atom penetrating into the Fe2Al5 phase. When Si atom occupies the vacancy site, it blocks easy diffusion path and results in the disappearance of tongue-like morphology.展开更多
In order to restrain the high pumping voltage of braking procedure which is harmful to the system of electric armored vehicle. Based on the analysis of pumping voltage of the braking procedure, the relation between pu...In order to restrain the high pumping voltage of braking procedure which is harmful to the system of electric armored vehicle. Based on the analysis of pumping voltage of the braking procedure, the relation between pumping voltage and PWM ratio is derived and a new digital control method to restrain the pumping voltage by changing PWM ratio is put forward. Because the capacitance is decreased effectively, the volume of controller is reduced and the performance to price ratio is improved. The results of computer simulation and experiment proved that this method is feasible and valid.展开更多
[Objective] The aim of this study was to investigate effects of rhubarb decoction with different concentrations on the isolated intestinal movement performance of Ophicephalus argus,and to discuss its pharmacological ...[Objective] The aim of this study was to investigate effects of rhubarb decoction with different concentrations on the isolated intestinal movement performance of Ophicephalus argus,and to discuss its pharmacological mechanism.[Method] With RM6240C biological signal collection and processing system,tension values of the isolated intestine before and after the treatment by rhubarb decoction with different concentrations were recorded by the isolated organ method.[Result] Rhubarb decoction with concentration of 0.062 and 0.125 g/ml showed obvious enhancement on the isolated intestinal contraction of Ophicephalus argus,while rhubarb decoction with concentration of 0.250 and 0.500 g/ml showed inhibition on the isolated intestinal contraction of Ophicephalus argus.There was an extremely significant difference in rhubarb decoction with concentration of lower than 0.500 g/ml and more than 0.500 g/ml.With the increase of rhubarb concentration,the intestinal movement of Ophicephalus argus enhanced,but the contraction frequency did not change obviously.[Conclusion] Rhubarb decoction has remarkable effects on the contraction of smooth muscle in the isolated intestines of Ophicephalus argus.展开更多
[Objective] The research aimed to investigate the bioturbation effects of Branchiura sowerbyi (Tubificidae) on the vertical transport of sedimentary particles in paddy field,and explore the bioturbation effects and ...[Objective] The research aimed to investigate the bioturbation effects of Branchiura sowerbyi (Tubificidae) on the vertical transport of sedimentary particles in paddy field,and explore the bioturbation effects and mechanism of benthic Annelida in coupling process of benthic-pelagic interface.[Method]Using chemically stable glass beads as tracers,the vertical transport of sedimentary particles in paddy field was analyzed comparatively with and without B.sowerbyi.[Result]After 10 days' bioturbation of B.sowerbyi,41.3% of the glass beads on the surface of sedimentary particles were transferred downward to the maximum depth of 9.4 cm,and the vertical transportation rate of sedimentary particles was 1.370×10-3/(g·cm2·d). 25.8% and 17.3% of glass beads at a depth of 6 cm were transferred upwards and downwards respectively after bioturbation,to the maximum depth of 5.2 and 2.7 cm respectively,and the vertical transportation rates of sedimentary particles were 8.557×10-4 and 5.738×10-4/(g·cm2·d) respectively.[Conclusion]The sedimentary particles on the surface and deep layer of the paddy field were vertically shifted by the physical activities of B.sowerbyi,thus changed the sedimentary environment.展开更多
The human-induced vertical vibration serviceability of low-frequency and lightweight footbridges is studied based on the moving mass-spring-damper(MMSD) biodynamic model, and the mass damper(TMD) with different op...The human-induced vertical vibration serviceability of low-frequency and lightweight footbridges is studied based on the moving mass-spring-damper(MMSD) biodynamic model, and the mass damper(TMD) with different optimal model parameters being used to control the vertical vibration.First, the MMSD biodynamic model is employed to simulate the pedestrians, and the time-varying control equations of the vertical dynamic coupling system of the pedestrian-bridgeTMD are established with the consideration of pedestrianbridge dynamic interaction; and the equations are solved by using the Runge-Kutta-Felhberg integral method with variable step size. Secondly, the footbridge dynamic response is calculated under the model of pedestrian-structure dynamic interaction and the model of moving load when the pedestrian pace frequency is consistent with the natural frequency of footbridge. Finally, a comparative study and analysis are made on the control effects of the vertical dynamic coupling system in different optimal models of the TMD. The calculation results show that the pedestrian-bridge dynamic interaction cannot be ignored when the vertical human-induced vibration serviceability of low-frequency and light-weight footbridge is evaluated. The TMD can effectively reduce the vibration under the resonance of pedestrian-bridge, and TMD parameters are recommended for the determination by the Warburton optimization model.展开更多
[Objective]The research aimed to explore the bioturbation effects of benthic fish Misgurnus anguillicaudatus on soil microorganism(microflora,biomass,and special physiological groups) of paddy field.[Method]The expe...[Objective]The research aimed to explore the bioturbation effects of benthic fish Misgurnus anguillicaudatus on soil microorganism(microflora,biomass,and special physiological groups) of paddy field.[Method]The experiments were conducted locally and quantitatively in field,using plate count and MPN methods.[Result]In the microflora of paddy soil tested,the quantity of bacteria is the largest,followed by actinomycetes and fungus.Compared with the control paddy fields,in rice-fish paddy fields the quantities of bacteria,actinomycetes and fungus were higher,at significance level P 〈0.05,P 〈0.01,and P 〈0.01 respectively.The microbial biomass C and N in rice-fish paddy fields is remarkably higher than those in control paddy fields,both at significance level P 〈0.01;the microbial biomass P in rice-fish paddy fields is higher than that in control paddy fields,but at significance level P 〈0.05.Benthic fish promotes the growth of soil azotobacter,cellulolytic bacteria,nitrobacteria,sulfur bacteria,and ammonifying bacteria,restricts the reproduction of nitrate reducing bacteria and sulfate reducing bacteria.[Conclusion]The benthic fish had important effects on microflora,microbial biomass,and special microorganism physiological groups of paddy soil,improves the living conditions of soil microorganisms,promotes the soil fertility and bio-chemical activity,which is beneficial for improving the supply ability of soil nutrients such as N,P,S,as well as the efficiency of nutrient utilization.展开更多
Buddhism and local cultural traditions have long protected wildlife species and their habitats in Tibetan-dominated areas of western Sichuan. In Daocheng County, the White Eared-pheasant (Crossoptilon crossoptilon) ha...Buddhism and local cultural traditions have long protected wildlife species and their habitats in Tibetan-dominated areas of western Sichuan. In Daocheng County, the White Eared-pheasant (Crossoptilon crossoptilon) has been afforded special protection by local people because it is conspicuous and white, a color with special symbolism for Buddhists. This and other cultural reasons have led to pheasants and forests benefiting in some areas. Pheasants were found during surveys between January 2003 and June 2004 in forests with varying degrees of local (non-formal) protection. However, there were significant signs that these traditional attitudes were changing in the face of three particular pressures brought to bear by better roads, improving access to and from the rest of China. The first was the development of a significant local demand for the Chinese caterpillar fungus (Cordyceps sinesis), which is much sought after throughout East Asia and mushrooms. Second, and more recent, is a dramatic increase in tourism from major Chinese cities, bringing non-Tibetan values into Daocheng County and changing the local attitudes to all animals. And then, there is a rise in income of the local population, resulting in a higher timber demand for building big houses, which impact all wildlife in the forest, but local attitudes to sacred forests have been retained so far in spite of this increased timber demand. Lessons should be learnt from the impact that unregulated tourism at Chonggu monastery, the most visited area in the county, has on the surrounding forests so that other sacred and non-sacred forests can best be protected for the long term. The alternative is that several Tibetan Plateau Galliformes, currently considered non-threatened because of their extensive distribution in a remote area, cannot be guaranteed such a healthy future.展开更多
文摘Past studies reveal the prevalence of anxiety,coupled with low motivation and disengagement among students in English-medium instruction(EMI)programs.Given the detrimental impact these negative emotions can have on learning outcomes,it is imperative that teachers establish positive emotional rapport with their students.This study explores how experienced and highly rated EMI lecturers at a Chinese university’s overseas campus use communication strategies to build rapport with their students during interactive academic activities.It identifies the strategies used by these lecturers and examines how the strategies facilitate the teaching-learning process.The data,consisting of 10 hours of tutorials and 10 hours of supervisor-student supervision meetings,is analyzed using an adapted Conversation Analysis(CA)approach.The analysis reveals three types of communication strategies(CSs)frequently used by lecturers:back-channeling,codeswitching,and co-creation of messages.By employing these strategies,the lecturers established a strong rapport with the students,which created an encouraging and supportive learning environment.Consequently,this positive atmosphere facilitated students’learning of content knowledge through English.The findings of this study have implications for the training of lecturers who encounter difficulties in establishing rapport with multilingual students in the EMI setting.
基金the National Basic Research Development of China(2011CB936003)the National Natural Science Foundation of China(50971116)。
文摘Photocatalytic splitting of water over p-type semiconductors is a promising strategy for production of hydrogen.However,the determination of rate law is rarely reported.To this purpose,copper oxide(CuO)is selected as a model photocathode in this study,and the photogenerated surface charge density,interfacial charge transfer rate constant and their relation to the water reduction rate(in terms of photocurrent)were investigated by a combination of(photo)electrochemical techniques.The results showed that the charge transfer rate constant is exponential-dependent on the surface charge density,and that the photocurrent equals to the product of the charge transfer rate constant and surface charge density.The reaction is first-order in terms of surface charge density.Such an unconventional rate law contrasts with the reports in literature.The charge density-dependent rate constant results from the Fermi level pinning(i.e.,Galvani potential is the main driving force for the reaction)due to accumulation of charge in the surface states and/or Frumkin behavior(i.e.,chemical potential is the main driving force).This study,therefore,may be helpful for further investigation on the mechanism of hydrogen evolution over a CuO photocathode and for designing more efficient CuO-based photocatalysts.
基金supported by the Guangxi Natural Science Foundation(2020GXNSFAA297266)Doctoral Research Foundation of Guilin University of Technology(GUTQDJJ2007059)Guangxi Hidden Metallic Mineral Exploration Key Laboratory。
文摘For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological index(RSEI)was calculated for the Lijiang River Basin in Guangxi Zhuang Autonomous Region for 1991,2001,2011,and 2021.Spatial autocorrelation analysis was employed to investigate spatiotemporal variations in the ecological environmental quality of the Lijiang River Basin.Furthermore,geographic detectors were used to quantitatively analyze influencing factors and their interaction effects on ecological environmental quality.The results verified that:1)From 1991 to 2021,the ecological environmental quality of the Lijiang River Basin demonstrated significant improvement.The area with good and excellent ecological environmental quality in proportion increased by 19.69%(3406.57 km^(2)),while the area with fair and poor ecological environmental quality in proportion decreased by 10.76%(1860.36 km^(2)).2)Spatially,the ecological environmental quality of the Lijiang River Basin exhibited a pattern of low quality in the central region and high quality in the periphery.Specifically,poor ecological environmental quality characterized the Guilin urban area,Pingle County,and Lingchuan County.3)From 1991 to 2021,a significant positive spatial correlation was observed in ecological environmental quality of the Lijiang River Basin.Areas with high-high agglomeration were predominantly forests and grasslands,indicating good ecological environmental quality,whereas areas with low-low agglomeration were dominated by cultivated land and construction land,indicating poor ecological environmental quality.4)Annual average precipitation and temperature exerted the most significant influence on the ecological environmental quality of the basin,and their interactions with other factors had the great influence.This study aimed to enhance understanding of the evolution of the ecological environment in the Lijiang River Basin of Guangxi Zhuang Autonomous Region and provide scientific guidance for decision-making and management related to ecology in the region.
文摘Thermodynamic and kinetic aspects of Sn nucleation and growth processes onto a glassy carbon electrode from SnCl2·2H2O dissolved in ethylene glycol solutions were studied.Typical reduction and oxidation peaks observed in voltammograms have demonstrated the capability of ethylene glycol solutions to electrodeposit Sn.The temperature-dependence of diffusion coefficient values derived from potentiodynamic and potentiostatic studies helped to determine and validate estimations of the activation energy for Sn(II)bulk diffusion.Chronoamperometric results have identified that,the suitable model to describe the early stage of Sn electrodeposition could be composed of Sn three-dimensional nucleation and diffusion-controlled growth and water reduction contributions,which was duly validated by theoretical and experimental approaches.From the model,typical kinetic parameters such as the nucleation frequency of Sn(A),number density of Sn nuclei(N_(0)),and diffusion coefficient of Sn(II)ions(D),were determined.The presence of Sn nuclei with excellent quality and their structures were verified using SEM,EDX,and XRD techniques.
基金supported by the European Union within the framework of the“National Laboratory for Autonomous Systems”(No.RRF-2.3.1-212022-00002)the Hungarian“Research on prime exploitation of the potential provided by the industrial digitalisation(No.ED-18-2-2018-0006)”the“Research on cooperative production and logistics systems to support a competitive and sustainable economy(No.TKP2021-NKTA-01)”。
文摘Research of autonomous manufacturing systems is motivated both by the new technical possibilities of cyber-physical systems and by the practical needs of the industry.Autonomous operation in semi-structured industrial environments can now be supported by advanced sensor technologies,digital twins,artificial intelligence and novel communication techniques.These enable real-time monitoring of production processes,situation recognition and prediction,automated and adaptive(re)planning,teamwork and performance improvement by learning.This paper summarizes the main requirements towards autonomous industrial robotics and suggests a generic workflow for realizing such systems.Application case studies will be presented from recent practice at HUN-REN SZTAKI in a broad range of domains such as assembly,welding,grinding,picking and placing,and machining.The various solutions have in common that they use a generic digital twin concept as their core.After making general recommendations for realizing autonomous robotic solutions in the industry,open issues for future research will be discussed.
基金Project (51071135) supported by the National Natural Science Foundation of ChinaProject (20114301110005) supported by the Ph. D.Programs Foundation of Ministry of Education of ChinaProject (10XZX15) supported by the Science Foundation of Xiangtan University,China
文摘The effect of Si on the growth kinetics of intermetallic compounds during the reaction of solid iron and molten aluminum was investigated with a scanning electron microscope coupled with an energy dispersive X-ray spectroscope, and hot-dip aluminized experiments. The results show that the intermetallic layer is composed of major Fe2Al5 and minor FeAl3. The Al-Fe-Si ternary phase, rl/rg, is formed in the Fe2Al5 layer. The tongue-like morphology of the Fe2Als layer becomes less distinct and disappears finally as the content of Si in aluminum bath increases. Si in the bath improves the prohibiting ability to the growth of Fe2Als and FeAl3. When the contents of Si are 0, 0.5%, 1.0%, 1.5%, 2.0% and 3.0%, the activation energies of Fe2Al5 are evaluated to be 207, 186, 169, 168, 167 and 172 kJ/mol, respectively. The reduction of the activation energy might result from the lattice distortion caused by Si atom penetrating into the Fe2Al5 phase. When Si atom occupies the vacancy site, it blocks easy diffusion path and results in the disappearance of tongue-like morphology.
文摘In order to restrain the high pumping voltage of braking procedure which is harmful to the system of electric armored vehicle. Based on the analysis of pumping voltage of the braking procedure, the relation between pumping voltage and PWM ratio is derived and a new digital control method to restrain the pumping voltage by changing PWM ratio is put forward. Because the capacitance is decreased effectively, the volume of controller is reduced and the performance to price ratio is improved. The results of computer simulation and experiment proved that this method is feasible and valid.
基金Supported by Teaching Reform Project of Tianjin Agricultural University (C-08-01)Scientific and Technological Project of Tianjin Sci-ence and Technology Commission (06YFGZNC02400)~~
文摘[Objective] The aim of this study was to investigate effects of rhubarb decoction with different concentrations on the isolated intestinal movement performance of Ophicephalus argus,and to discuss its pharmacological mechanism.[Method] With RM6240C biological signal collection and processing system,tension values of the isolated intestine before and after the treatment by rhubarb decoction with different concentrations were recorded by the isolated organ method.[Result] Rhubarb decoction with concentration of 0.062 and 0.125 g/ml showed obvious enhancement on the isolated intestinal contraction of Ophicephalus argus,while rhubarb decoction with concentration of 0.250 and 0.500 g/ml showed inhibition on the isolated intestinal contraction of Ophicephalus argus.There was an extremely significant difference in rhubarb decoction with concentration of lower than 0.500 g/ml and more than 0.500 g/ml.With the increase of rhubarb concentration,the intestinal movement of Ophicephalus argus enhanced,but the contraction frequency did not change obviously.[Conclusion] Rhubarb decoction has remarkable effects on the contraction of smooth muscle in the isolated intestines of Ophicephalus argus.
基金Supported by National Natural Science Foundation of China(31070421 )Human Resources and Social Security Department Students Abroad Science and Technology Activities Preferred Foundation (Human and Social Council Issued 2008-86)+8 种基金Talent Development Fund Project in Jilin Province (Jilin 2007-259)Jilin Province Science and Technology Development Project (20060577 )Technology Project Jilin Provincial Ministry of Education (20094352006113 20071692010150)The Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (2005-546)Changchun Normal University Natural Science Foundation(2009002)Northeast Normal University Natural Science Foundation for Young Scholar(20050406)~~
文摘[Objective] The research aimed to investigate the bioturbation effects of Branchiura sowerbyi (Tubificidae) on the vertical transport of sedimentary particles in paddy field,and explore the bioturbation effects and mechanism of benthic Annelida in coupling process of benthic-pelagic interface.[Method]Using chemically stable glass beads as tracers,the vertical transport of sedimentary particles in paddy field was analyzed comparatively with and without B.sowerbyi.[Result]After 10 days' bioturbation of B.sowerbyi,41.3% of the glass beads on the surface of sedimentary particles were transferred downward to the maximum depth of 9.4 cm,and the vertical transportation rate of sedimentary particles was 1.370×10-3/(g·cm2·d). 25.8% and 17.3% of glass beads at a depth of 6 cm were transferred upwards and downwards respectively after bioturbation,to the maximum depth of 5.2 and 2.7 cm respectively,and the vertical transportation rates of sedimentary particles were 8.557×10-4 and 5.738×10-4/(g·cm2·d) respectively.[Conclusion]The sedimentary particles on the surface and deep layer of the paddy field were vertically shifted by the physical activities of B.sowerbyi,thus changed the sedimentary environment.
基金The National Natural Science Foundation of China(No.51508257,51668042,51578274)the Yangtze River Scholar and the Innovation Team of M inistry of Education(No.IRT13068)the Scientific Research Project of Gansu Higher Education(No.2015B-34)
文摘The human-induced vertical vibration serviceability of low-frequency and lightweight footbridges is studied based on the moving mass-spring-damper(MMSD) biodynamic model, and the mass damper(TMD) with different optimal model parameters being used to control the vertical vibration.First, the MMSD biodynamic model is employed to simulate the pedestrians, and the time-varying control equations of the vertical dynamic coupling system of the pedestrian-bridgeTMD are established with the consideration of pedestrianbridge dynamic interaction; and the equations are solved by using the Runge-Kutta-Felhberg integral method with variable step size. Secondly, the footbridge dynamic response is calculated under the model of pedestrian-structure dynamic interaction and the model of moving load when the pedestrian pace frequency is consistent with the natural frequency of footbridge. Finally, a comparative study and analysis are made on the control effects of the vertical dynamic coupling system in different optimal models of the TMD. The calculation results show that the pedestrian-bridge dynamic interaction cannot be ignored when the vertical human-induced vibration serviceability of low-frequency and light-weight footbridge is evaluated. The TMD can effectively reduce the vibration under the resonance of pedestrian-bridge, and TMD parameters are recommended for the determination by the Warburton optimization model.
基金Supported by Human Resources and Social Security Department Students Abroad Science and Technology Activities Preferred Foundation (Human and Social Council Issued 2008-86)Talent Development Fund Project in Jilin Province (Jilin 2007-259)+6 种基金Jilin Province Science and Technology Development Project (20060577 )Technology Project Jilin Provincial Ministry of Education (200943520061132007169)The Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry (2005-546 )Science Foundation of Changchun Teachers University (2009002)Northeast Normal University Natural Science Foundation for Young Scholar (20050406)~~
文摘[Objective]The research aimed to explore the bioturbation effects of benthic fish Misgurnus anguillicaudatus on soil microorganism(microflora,biomass,and special physiological groups) of paddy field.[Method]The experiments were conducted locally and quantitatively in field,using plate count and MPN methods.[Result]In the microflora of paddy soil tested,the quantity of bacteria is the largest,followed by actinomycetes and fungus.Compared with the control paddy fields,in rice-fish paddy fields the quantities of bacteria,actinomycetes and fungus were higher,at significance level P 〈0.05,P 〈0.01,and P 〈0.01 respectively.The microbial biomass C and N in rice-fish paddy fields is remarkably higher than those in control paddy fields,both at significance level P 〈0.01;the microbial biomass P in rice-fish paddy fields is higher than that in control paddy fields,but at significance level P 〈0.05.Benthic fish promotes the growth of soil azotobacter,cellulolytic bacteria,nitrobacteria,sulfur bacteria,and ammonifying bacteria,restricts the reproduction of nitrate reducing bacteria and sulfate reducing bacteria.[Conclusion]The benthic fish had important effects on microflora,microbial biomass,and special microorganism physiological groups of paddy soil,improves the living conditions of soil microorganisms,promotes the soil fertility and bio-chemical activity,which is beneficial for improving the supply ability of soil nutrients such as N,P,S,as well as the efficiency of nutrient utilization.
基金supported by the National Science Foundation of China (Grant No. 30800101)the Chicago Zoological Society, the World Pheasant Association and the Critical Ecosystem Partnership FundPeter Garson (Chair,WPA-IUCN Pheasant Specialist Group) provided constructive advice on the work and helped facilitate financial support
文摘Buddhism and local cultural traditions have long protected wildlife species and their habitats in Tibetan-dominated areas of western Sichuan. In Daocheng County, the White Eared-pheasant (Crossoptilon crossoptilon) has been afforded special protection by local people because it is conspicuous and white, a color with special symbolism for Buddhists. This and other cultural reasons have led to pheasants and forests benefiting in some areas. Pheasants were found during surveys between January 2003 and June 2004 in forests with varying degrees of local (non-formal) protection. However, there were significant signs that these traditional attitudes were changing in the face of three particular pressures brought to bear by better roads, improving access to and from the rest of China. The first was the development of a significant local demand for the Chinese caterpillar fungus (Cordyceps sinesis), which is much sought after throughout East Asia and mushrooms. Second, and more recent, is a dramatic increase in tourism from major Chinese cities, bringing non-Tibetan values into Daocheng County and changing the local attitudes to all animals. And then, there is a rise in income of the local population, resulting in a higher timber demand for building big houses, which impact all wildlife in the forest, but local attitudes to sacred forests have been retained so far in spite of this increased timber demand. Lessons should be learnt from the impact that unregulated tourism at Chonggu monastery, the most visited area in the county, has on the surrounding forests so that other sacred and non-sacred forests can best be protected for the long term. The alternative is that several Tibetan Plateau Galliformes, currently considered non-threatened because of their extensive distribution in a remote area, cannot be guaranteed such a healthy future.