Ocean is a distinctive and prior resource in Qingdao. This paper makes summary and analysis of the practice of constructing marine ecological civilization in Qingdao and offers suggestions for the future development o...Ocean is a distinctive and prior resource in Qingdao. This paper makes summary and analysis of the practice of constructing marine ecological civilization in Qingdao and offers suggestions for the future development of the city. With the implementation of the city's strategy of =Protecting the bay and developing the city on the bay", the suggestions focus on between management & utilization, so as to establish the harmony between the optimal utilization of madne resource and marine ecological environment protection, and to consistently promote marine ecological civilization展开更多
The now and heat transfer characteristics in tenon joint gap between turbine blade and disk have been investigated experimentally with a scale up model. The characteristics of flow and heat transfer in this speCial ga...The now and heat transfer characteristics in tenon joint gap between turbine blade and disk have been investigated experimentally with a scale up model. The characteristics of flow and heat transfer in this speCial gap passage have been analyzed. The results are useful for beat transfer analysis in turbine design.展开更多
A thermal-mechanical and micro-macro coupled finite element(FE) model for the hot extrusion process of large-scale thick-walled Inconel 625 pipe was developed based on the DEFORM-2D platform.Then,the influence rules...A thermal-mechanical and micro-macro coupled finite element(FE) model for the hot extrusion process of large-scale thick-walled Inconel 625 pipe was developed based on the DEFORM-2D platform.Then,the influence rules of the key extrusion parameters on the average grain size and grain uniformity of the extruded pipe were revealed.The results show that with the increase of initial billet temperature,extrusion speed and friction coefficient,the grain uniformity is firstly improved and then deteriorated.Larger extrusion ratio leads to more uniform grain distribution.With the increase of initial billet temperature,the average grain size of the pipe first decreases and then increases.Additionally,larger extrusion ratio can bring smaller average grain size.The extrusion speed and friction coefficient have slight effects on the average grain size of the extruded pipe.展开更多
With a water-supply network by dynamic programming. The minimal as an example, the network was optimized annual discounted costs were taken as an objective function and node pressure etc. as constraint conditions. The...With a water-supply network by dynamic programming. The minimal as an example, the network was optimized annual discounted costs were taken as an objective function and node pressure etc. as constraint conditions. The alternative pipe diameters were optimized as per enumeration method and the group allowing objective function with the least values would be the optimized one. It is proved the optimized pipe network reduced by 11.49% in terms of cost and the optimized ben- efits proved much significant.展开更多
With the background of severe rocky desertification in the west of China and the ohjective of ecological environment construction and poverty elimination, the management information system of rocky desertification was...With the background of severe rocky desertification in the west of China and the ohjective of ecological environment construction and poverty elimination, the management information system of rocky desertification was designed according to the natural and humane characteristics in Nanchuan of Sichuan Province. The system was composed of data management module, information query module for rocky desertification, spatial analysis module and dynamic monitoring module.展开更多
Objective] Field and laboratory observation was conducted to investigate Clubiona corrugate. [Method] The trials investigated the bio-ecology and behavior of the spider C. corrugate. [Result] The spider overwintered w...Objective] Field and laboratory observation was conducted to investigate Clubiona corrugate. [Method] The trials investigated the bio-ecology and behavior of the spider C. corrugate. [Result] The spider overwintered with spiderlings, adults and instars turn into adults after 6-8 molts. It had 2-3 generations each year in Hunan, and it owned the character of overlapping of generation in paddies. The average duration of generations of C. corrugate was 158.2 days, and the survival days av-eraged 223.2 days. The female and male mated several times without cannibalistic behavior, average number of eggs female laid throughout its adult life was 371.5, and hatchability can get 85.4%. The sex ratio was 1∶1. Its capability of resistance to starvation and drought was strong. Through indoor observation, the spider can sur-vive 25-61 days under the condition of no water and food. [Conclusion] The behav-ior of C. corrugate was also recorded in detail, and female usual y has a strong a-bility to protect their egg-sacs and spiderlings. At present, the bio-ecology and be-havior of the spider C. corrugate had not been reported.展开更多
The field emission from pure boron-nitride nanotube and boron-nitride nanotube encapsu- lated with natrium atoms with the electric field perpendicular to the axis of nanotubes is simulated based on a self-consistent m...The field emission from pure boron-nitride nanotube and boron-nitride nanotube encapsu- lated with natrium atoms with the electric field perpendicular to the axis of nanotubes is simulated based on a self-consistent method using the density-functional formalism. It has been found that the nearly-free-electron states in boron-nitride nanotube would perform very well in field emissions after natrium atom encapsulation. The characters of total energy distribution curves are analyzed to seek the function of nearly-free-electron states in the field emission, with special attention to response of the emission current to the external electric field. At last, the perpendicular emission geometry is found to possess a very sensitive response degree which is supposed to be related to specific expansion orientation of the nearly-free-electron states in this system.展开更多
The self-organization mapping (SOM) neural network algorithm is a new method used to identify the ecosystem service zones at regional extent. According to the ecosystem assessment framework of Millennium Ecosystem A...The self-organization mapping (SOM) neural network algorithm is a new method used to identify the ecosystem service zones at regional extent. According to the ecosystem assessment framework of Millennium Ecosystem Assessment ( MA), this paper develops an indicator system and conducts a spatial cluster analysis at the 1km by I km grid pixel scale with the SOM neural network algorithm to sort the core ecosystem services over the vertical and horizontal dimensions. A case study was carried out in Xilingol League. The ecosystem services in Xilingol League could be divided to six different ecological zones. The SOM neural network algorithm was capable of identifying the similarities among the input data automatically. The research provides both spatially and temporally valuable information targeted sustainable ecosystem management for decision-makers.展开更多
A continuous semisolid extending extrusion (CSEP) method was proposed. Temperature field and metal flow during continuous semisolid extending extrusion process of 6201 alloy tube were studied. During the process, th...A continuous semisolid extending extrusion (CSEP) method was proposed. Temperature field and metal flow during continuous semisolid extending extrusion process of 6201 alloy tube were studied. During the process, the temperature in the roll-shoe cavity decreases gradually, and the isothermal lines of the alloy deviate from the shoe side to the work roll side in the roll–shoe gap. Metal flow velocity decreases gradually from the surface of the work roll to the surface of the shoe. In the extrusion mould, alloy temperature decreases gradually from the entrance to the exit and from the center to the sidewall of the mould. The extending cavity is radially filled with the alloy. The flow lines in the tube corresponding to the centers of the splitflow orifices and the welding gaps are dense, and the corresponding harness values are high; there are 8 transitional bands between them. In order to prepare 6201 alloy tubes with good surface quality, the pouring temperature from 750 ℃ to 780 ℃ was suggested.展开更多
Strategic environment assessment (SEA) and ecosystem health are two new ideas on environmental management. On the basis of reviewing some relevant literature, this paper made discussions on the ecological sustainabili...Strategic environment assessment (SEA) and ecosystem health are two new ideas on environmental management. On the basis of reviewing some relevant literature, this paper made discussions on the ecological sustainability target of SEA, the content of ecosystem health as well as the interrelations between SEA and ecosystem health. For a good SEA, its ecological sustainability principles should be provided with distinct content and a general assessment system. A framework for ecosystem health assessment was established according to the content of ecosystem health, and combined into SEA as SEA抯 ecological sustainability target, we can effectively guide decision-makers to make suitable indigenous means and local solutions. , The basic principles and procedure of SEA for ecosystem health are also discussed in the paper.展开更多
Based on the fundamental relationship among the circuit power, the circuit delay and the supply voltage, four theorems associated with the application of dynamic voltage scaling (DVS) policies are proposed and prove...Based on the fundamental relationship among the circuit power, the circuit delay and the supply voltage, four theorems associated with the application of dynamic voltage scaling (DVS) policies are proposed and proved. First, the existence characteristics of the optimal supply voltage for a single task are proved, which suggests that the optimal supply voltage for the single task should be selected only within a one-dimensional term, and the corresponding task end time by the optimal supply voltage should be identical with its deadline. Then, it is pointed out that the minimum energy consumption that the DVS policy can obtain when completing a single task is certainly lower than that of the dynamic power management (DPM) policy or the combined DVS+DPM policy under the same conditions. Finally, the theorem of energy consumption minimization for a multi-task group is proposed, which declares that it is necessary to keep the processor in the execution state during the whole task period to obtain the minimum energy consumption, while satisfying the deadline constraints of any task.展开更多
In order to solve the urgent problem of how to manage and sustain highway tunnels with advanced information technology with the background of the rapid development in the modem traffic, and achieve the cost- effective...In order to solve the urgent problem of how to manage and sustain highway tunnels with advanced information technology with the background of the rapid development in the modem traffic, and achieve the cost- effectiveness optimal principle objectives under the premise of guaranteeing a smooth flow of traffic; a highway tunnel maintenance and management system framework and the key modules were proposed. First, the determined highway tunnel condition assessment index system was established according to the result of expert consulting forms. Secondly, the tunnel diseases, the corresponding maintenance measurements, and many-to-many relationship between diseases and maintenance measurements were introduced. Then, three kinds of 0-1 integer programming models were built according to different tunnel operators' needs in the optimization decision module. Finally, the further development and implementation of the system was prospected. The research results can provide references to tunnel researchers and managers.展开更多
The eXtensible markup language (XML) is a kind of new meta language for replacing HTML and has many advantages. Traditional engineering documents have too many expression forms to be expediently managed and have no dy...The eXtensible markup language (XML) is a kind of new meta language for replacing HTML and has many advantages. Traditional engineering documents have too many expression forms to be expediently managed and have no dynamic correlation functions. This paper introduces a new method and uses XML to store and manage engineering documents to realize the format unity of engineering documents and their dynamic correlations.展开更多
In the research, problems and damages of soil erosions in West -East Natural Gas Transmission were analyzed; the reasons were summarized and the characteristics of soil erosion were researched in order to explore prin...In the research, problems and damages of soil erosions in West -East Natural Gas Transmission were analyzed; the reasons were summarized and the characteristics of soil erosion were researched in order to explore principles of pipeline prevention and seek countermeasures.展开更多
This paper describes a robust support vector regression (SVR) methodology, which can offer superior performance for important process engineering problems. The method incorporates hybrid support vector regression an...This paper describes a robust support vector regression (SVR) methodology, which can offer superior performance for important process engineering problems. The method incorporates hybrid support vector regression and genetic algorithm technique (SVR-GA) for efficient tuning of SVR meta-parameters. The algorithm has been applied for prediction of pressure drop of solid liquid slurry flow. A comparison with selected correlations in the lit- erature showed that the developed SVR correlation noticeably improved the prediction of pressure drop over a wide range of operating conditions, physical properties, and pipe diameters.展开更多
Toxic cyanobacteria(TCB) are well-known worldwide for their adverse impacts on humans. Species compositions and seasonal variations of TCB in reservoirs depend on interactions between physical and chemical factors. Th...Toxic cyanobacteria(TCB) are well-known worldwide for their adverse impacts on humans. Species compositions and seasonal variations of TCB in reservoirs depend on interactions between physical and chemical factors. This study was conducted to evaluate the water quality in the Aha Reservoir, Southwest China, focusing on cyanobacteria and cyanotoxins. Water samples were collected weekly or biweekly from May to September of 2015 and used to delineate temporal variations in density and distribution of toxic cyanobacteria and cyanotoxins in the reservoir. Toxic cyanobacteria identified consisted of Aphanizomenon flos-aquae, Pseudanabaena limnetica, Cylindrospermopsis sp., and Microcystis sp., with Aphanizomenon flos-aquae and Pseudanabaena limnetica being the most common and significant toxic genera. The total biomass of cyanobacteria was 17.0 mg/L. Identification and quantification of microcystin variants were conducted by high performance liquid chromatography(HPLC) using a system equipped with a photodiode array detector. Microcystin levels were between 0–3.0 μg/L, MC-RR was around 0–3.0 μg/L and MC-LR was approximately 0–0.9 μg/L. Overall, the results of this study indicate that the investigated reservoirs should be monitored regularly to minimize potential health risks to the human population.展开更多
Multiple size group (MUSIG) model combined with a threedimensional twofluid model were em ployed to predict subcooled boiling flow of liquid nitrogen in a vertical upward tube. Based on the mechanism of boiling heat...Multiple size group (MUSIG) model combined with a threedimensional twofluid model were em ployed to predict subcooled boiling flow of liquid nitrogen in a vertical upward tube. Based on the mechanism of boiling heat transfer, some important bubble model parameters were amended to be applicable to the modeling of liquid nitrogen. The distribution of different discrete bubble classes was demonstrated numerically and the distribu tion patterns of void fraction in the wallheated tube were analyzed. It was found that the average void fraction in creases nonlinearly along the axial direction with wall heat flux and it decreases with inlet mass flow rate and sub cooled temperature. The local void fraction exhibited a Ushape distribution in the radial direction. The partition of the wall heat flux along the tube was obtained. The results showed that heat flux consumed on evaporation is the leading part of surface heat transfer at the rear region of subcooled boiling. The turning point in the pressure drop curve reflects the instability of bubbly flow. Good agreement was achieved on the local heat transfer coefficient aalnst experimental measurements, which demonstrated the accuracy of the numerical model.展开更多
Community-based natural resource management in northeast India has a long history. Indigenous knowledge and adaptation are the collective information, with improvement from generation to generation. The expectation is...Community-based natural resource management in northeast India has a long history. Indigenous knowledge and adaptation are the collective information, with improvement from generation to generation. The expectation is that under community control, local expertise on biodiversity will play a significant role in natural resource management through traditional practices. This paper discusses the characteristics and application of the traditional ecological knowledge of aboriginal peoples in northeast India and its role in natural resource management. Examples are provided in two different eco-cultural landscapes, i.e., Demazong (the Buddhist eco-cultural landscape in Sikkim Himalaya) and the Apatani eco-cultural landscape in Arunachal Pradesh, which illustrate the utility value of traditional ecological knowledge in sustainable natural resource management. Both eco-cultural landscapes are indeed very complex and highly evolved systems with high levels of economic and ecological efficiencies. The paper concludes that traditional ecological knowledge systems and institutions could serve as entry points into the sustainable utilization and management of natural resources. This could be achieved through the exploration of the cultural practices of the local people and integrating useful aspects into the modern natural resource management expertise. With rapidly depleting biodiversity in the developing tropic regions, there is a greater utilization today than ever before of the value of respecting the "Sacred" as a tool towards better conservation of natural resources.展开更多
文摘Ocean is a distinctive and prior resource in Qingdao. This paper makes summary and analysis of the practice of constructing marine ecological civilization in Qingdao and offers suggestions for the future development of the city. With the implementation of the city's strategy of =Protecting the bay and developing the city on the bay", the suggestions focus on between management & utilization, so as to establish the harmony between the optimal utilization of madne resource and marine ecological environment protection, and to consistently promote marine ecological civilization
文摘The now and heat transfer characteristics in tenon joint gap between turbine blade and disk have been investigated experimentally with a scale up model. The characteristics of flow and heat transfer in this speCial gap passage have been analyzed. The results are useful for beat transfer analysis in turbine design.
基金Project(2009ZX04005-031-11)supported by the Major National Science and Technology Special Project of ChinaProject(KP200911)supported by the Research Fund of State Key Laboratory of Solidification Processing of ChinaProject(B08040)supported by the"111"Project of China
文摘A thermal-mechanical and micro-macro coupled finite element(FE) model for the hot extrusion process of large-scale thick-walled Inconel 625 pipe was developed based on the DEFORM-2D platform.Then,the influence rules of the key extrusion parameters on the average grain size and grain uniformity of the extruded pipe were revealed.The results show that with the increase of initial billet temperature,extrusion speed and friction coefficient,the grain uniformity is firstly improved and then deteriorated.Larger extrusion ratio leads to more uniform grain distribution.With the increase of initial billet temperature,the average grain size of the pipe first decreases and then increases.Additionally,larger extrusion ratio can bring smaller average grain size.The extrusion speed and friction coefficient have slight effects on the average grain size of the extruded pipe.
文摘With a water-supply network by dynamic programming. The minimal as an example, the network was optimized annual discounted costs were taken as an objective function and node pressure etc. as constraint conditions. The alternative pipe diameters were optimized as per enumeration method and the group allowing objective function with the least values would be the optimized one. It is proved the optimized pipe network reduced by 11.49% in terms of cost and the optimized ben- efits proved much significant.
基金the National Science and Technology Key Project (2006BAC01A16)Program of Chongqing Science Committee (2004-8258)~~
文摘With the background of severe rocky desertification in the west of China and the ohjective of ecological environment construction and poverty elimination, the management information system of rocky desertification was designed according to the natural and humane characteristics in Nanchuan of Sichuan Province. The system was composed of data management module, information query module for rocky desertification, spatial analysis module and dynamic monitoring module.
基金Supported by National Natural Science Foundation of China[31472017]National Natural Science Foundation of China[31272339]+1 种基金National Natural Science Foundation of China[31071943]Major Program of Department of Science and Technology of Hunan Province[2014FJ2003]~~
文摘Objective] Field and laboratory observation was conducted to investigate Clubiona corrugate. [Method] The trials investigated the bio-ecology and behavior of the spider C. corrugate. [Result] The spider overwintered with spiderlings, adults and instars turn into adults after 6-8 molts. It had 2-3 generations each year in Hunan, and it owned the character of overlapping of generation in paddies. The average duration of generations of C. corrugate was 158.2 days, and the survival days av-eraged 223.2 days. The female and male mated several times without cannibalistic behavior, average number of eggs female laid throughout its adult life was 371.5, and hatchability can get 85.4%. The sex ratio was 1∶1. Its capability of resistance to starvation and drought was strong. Through indoor observation, the spider can sur-vive 25-61 days under the condition of no water and food. [Conclusion] The behav-ior of C. corrugate was also recorded in detail, and female usual y has a strong a-bility to protect their egg-sacs and spiderlings. At present, the bio-ecology and be-havior of the spider C. corrugate had not been reported.
文摘The field emission from pure boron-nitride nanotube and boron-nitride nanotube encapsu- lated with natrium atoms with the electric field perpendicular to the axis of nanotubes is simulated based on a self-consistent method using the density-functional formalism. It has been found that the nearly-free-electron states in boron-nitride nanotube would perform very well in field emissions after natrium atom encapsulation. The characters of total energy distribution curves are analyzed to seek the function of nearly-free-electron states in the field emission, with special attention to response of the emission current to the external electric field. At last, the perpendicular emission geometry is found to possess a very sensitive response degree which is supposed to be related to specific expansion orientation of the nearly-free-electron states in this system.
基金Supported by the National Scientific Foundation of China(4080123170873118)+6 种基金the Chinese Academy of Sciences(KZCX2-YW-305-2KSCX2-YW-N-039KZCX2-YW-326-1)the Ministry of Science and Technology of China(2006DFB91912012006BAC08B032006BAC08B062008BAK47B02)~~
文摘The self-organization mapping (SOM) neural network algorithm is a new method used to identify the ecosystem service zones at regional extent. According to the ecosystem assessment framework of Millennium Ecosystem Assessment ( MA), this paper develops an indicator system and conducts a spatial cluster analysis at the 1km by I km grid pixel scale with the SOM neural network algorithm to sort the core ecosystem services over the vertical and horizontal dimensions. A case study was carried out in Xilingol League. The ecosystem services in Xilingol League could be divided to six different ecological zones. The SOM neural network algorithm was capable of identifying the similarities among the input data automatically. The research provides both spatially and temporally valuable information targeted sustainable ecosystem management for decision-makers.
基金Projects (51034002, 50974038) supported by the National Natural Science Foundation of ChinaProject (132002) supported by the Fok Ying Tong Education FoundationProject (2011CB610405) supported by National Basic Research Program of China
文摘A continuous semisolid extending extrusion (CSEP) method was proposed. Temperature field and metal flow during continuous semisolid extending extrusion process of 6201 alloy tube were studied. During the process, the temperature in the roll-shoe cavity decreases gradually, and the isothermal lines of the alloy deviate from the shoe side to the work roll side in the roll–shoe gap. Metal flow velocity decreases gradually from the surface of the work roll to the surface of the shoe. In the extrusion mould, alloy temperature decreases gradually from the entrance to the exit and from the center to the sidewall of the mould. The extending cavity is radially filled with the alloy. The flow lines in the tube corresponding to the centers of the splitflow orifices and the welding gaps are dense, and the corresponding harness values are high; there are 8 transitional bands between them. In order to prepare 6201 alloy tubes with good surface quality, the pouring temperature from 750 ℃ to 780 ℃ was suggested.
文摘Strategic environment assessment (SEA) and ecosystem health are two new ideas on environmental management. On the basis of reviewing some relevant literature, this paper made discussions on the ecological sustainability target of SEA, the content of ecosystem health as well as the interrelations between SEA and ecosystem health. For a good SEA, its ecological sustainability principles should be provided with distinct content and a general assessment system. A framework for ecosystem health assessment was established according to the content of ecosystem health, and combined into SEA as SEA抯 ecological sustainability target, we can effectively guide decision-makers to make suitable indigenous means and local solutions. , The basic principles and procedure of SEA for ecosystem health are also discussed in the paper.
文摘Based on the fundamental relationship among the circuit power, the circuit delay and the supply voltage, four theorems associated with the application of dynamic voltage scaling (DVS) policies are proposed and proved. First, the existence characteristics of the optimal supply voltage for a single task are proved, which suggests that the optimal supply voltage for the single task should be selected only within a one-dimensional term, and the corresponding task end time by the optimal supply voltage should be identical with its deadline. Then, it is pointed out that the minimum energy consumption that the DVS policy can obtain when completing a single task is certainly lower than that of the dynamic power management (DPM) policy or the combined DVS+DPM policy under the same conditions. Finally, the theorem of energy consumption minimization for a multi-task group is proposed, which declares that it is necessary to keep the processor in the execution state during the whole task period to obtain the minimum energy consumption, while satisfying the deadline constraints of any task.
基金The US National Science Foundation(No.CM M I-0408390,CM M I-0644552)the National Natural Science Foundation of China(No.U1134206,51250110075,51150110478)+1 种基金the Western Project of M inistry of Communications of China(No.0901005C)the Natural Science Foundation of Jiangsu Province(No.BK200910046)
文摘In order to solve the urgent problem of how to manage and sustain highway tunnels with advanced information technology with the background of the rapid development in the modem traffic, and achieve the cost- effectiveness optimal principle objectives under the premise of guaranteeing a smooth flow of traffic; a highway tunnel maintenance and management system framework and the key modules were proposed. First, the determined highway tunnel condition assessment index system was established according to the result of expert consulting forms. Secondly, the tunnel diseases, the corresponding maintenance measurements, and many-to-many relationship between diseases and maintenance measurements were introduced. Then, three kinds of 0-1 integer programming models were built according to different tunnel operators' needs in the optimization decision module. Finally, the further development and implementation of the system was prospected. The research results can provide references to tunnel researchers and managers.
文摘The eXtensible markup language (XML) is a kind of new meta language for replacing HTML and has many advantages. Traditional engineering documents have too many expression forms to be expediently managed and have no dynamic correlation functions. This paper introduces a new method and uses XML to store and manage engineering documents to realize the format unity of engineering documents and their dynamic correlations.
基金Supported by Scientific Research Program of Water Resources Department of the Xinjiang Uygur Autonomous Region (xjsl-2011-11)Young Core Project of Northwest A&F University (KZCXI-10-4-1)~~
文摘In the research, problems and damages of soil erosions in West -East Natural Gas Transmission were analyzed; the reasons were summarized and the characteristics of soil erosion were researched in order to explore principles of pipeline prevention and seek countermeasures.
文摘This paper describes a robust support vector regression (SVR) methodology, which can offer superior performance for important process engineering problems. The method incorporates hybrid support vector regression and genetic algorithm technique (SVR-GA) for efficient tuning of SVR meta-parameters. The algorithm has been applied for prediction of pressure drop of solid liquid slurry flow. A comparison with selected correlations in the lit- erature showed that the developed SVR correlation noticeably improved the prediction of pressure drop over a wide range of operating conditions, physical properties, and pipe diameters.
基金Supported by the Department of Science and Technology of Guizhou Province(Nos.[2015]2001,[2017]2863,[2018]5805)the Education Department of Guizhou Province(No.KY[2017]032)the Water Resources Department of Guizhou Province(No.KT201401)
文摘Toxic cyanobacteria(TCB) are well-known worldwide for their adverse impacts on humans. Species compositions and seasonal variations of TCB in reservoirs depend on interactions between physical and chemical factors. This study was conducted to evaluate the water quality in the Aha Reservoir, Southwest China, focusing on cyanobacteria and cyanotoxins. Water samples were collected weekly or biweekly from May to September of 2015 and used to delineate temporal variations in density and distribution of toxic cyanobacteria and cyanotoxins in the reservoir. Toxic cyanobacteria identified consisted of Aphanizomenon flos-aquae, Pseudanabaena limnetica, Cylindrospermopsis sp., and Microcystis sp., with Aphanizomenon flos-aquae and Pseudanabaena limnetica being the most common and significant toxic genera. The total biomass of cyanobacteria was 17.0 mg/L. Identification and quantification of microcystin variants were conducted by high performance liquid chromatography(HPLC) using a system equipped with a photodiode array detector. Microcystin levels were between 0–3.0 μg/L, MC-RR was around 0–3.0 μg/L and MC-LR was approximately 0–0.9 μg/L. Overall, the results of this study indicate that the investigated reservoirs should be monitored regularly to minimize potential health risks to the human population.
基金Supported by the National Natural Science Foundation of China (51106119, 81100707), the Fundamental Research Funds for the Central University of China, Doctoral Fund of Ministry of Education (20110201120052) and the National Science and Technology Sur0orting Item (2012BAA08B03).
文摘Multiple size group (MUSIG) model combined with a threedimensional twofluid model were em ployed to predict subcooled boiling flow of liquid nitrogen in a vertical upward tube. Based on the mechanism of boiling heat transfer, some important bubble model parameters were amended to be applicable to the modeling of liquid nitrogen. The distribution of different discrete bubble classes was demonstrated numerically and the distribu tion patterns of void fraction in the wallheated tube were analyzed. It was found that the average void fraction in creases nonlinearly along the axial direction with wall heat flux and it decreases with inlet mass flow rate and sub cooled temperature. The local void fraction exhibited a Ushape distribution in the radial direction. The partition of the wall heat flux along the tube was obtained. The results showed that heat flux consumed on evaporation is the leading part of surface heat transfer at the rear region of subcooled boiling. The turning point in the pressure drop curve reflects the instability of bubbly flow. Good agreement was achieved on the local heat transfer coefficient aalnst experimental measurements, which demonstrated the accuracy of the numerical model.
文摘Community-based natural resource management in northeast India has a long history. Indigenous knowledge and adaptation are the collective information, with improvement from generation to generation. The expectation is that under community control, local expertise on biodiversity will play a significant role in natural resource management through traditional practices. This paper discusses the characteristics and application of the traditional ecological knowledge of aboriginal peoples in northeast India and its role in natural resource management. Examples are provided in two different eco-cultural landscapes, i.e., Demazong (the Buddhist eco-cultural landscape in Sikkim Himalaya) and the Apatani eco-cultural landscape in Arunachal Pradesh, which illustrate the utility value of traditional ecological knowledge in sustainable natural resource management. Both eco-cultural landscapes are indeed very complex and highly evolved systems with high levels of economic and ecological efficiencies. The paper concludes that traditional ecological knowledge systems and institutions could serve as entry points into the sustainable utilization and management of natural resources. This could be achieved through the exploration of the cultural practices of the local people and integrating useful aspects into the modern natural resource management expertise. With rapidly depleting biodiversity in the developing tropic regions, there is a greater utilization today than ever before of the value of respecting the "Sacred" as a tool towards better conservation of natural resources.