The reverse generation current under high-gate-voltage stress condition in LDD nMOSFET's is studied. We find that the generation current peak decreases as the stress time increases. We ascribe this finding to the dom...The reverse generation current under high-gate-voltage stress condition in LDD nMOSFET's is studied. We find that the generation current peak decreases as the stress time increases. We ascribe this finding to the dominating oxide trapped electrons that reduce the effective drain bias, lowering the maximal generation rate. The density of the effective trapped electrons affecting the effective drain bias is calculated with our model.展开更多
The supply and demand features of China electric power market are elaborated in this paper, based on the data of power production and demand in the first quarter 2001, and the present situation on power supply and dem...The supply and demand features of China electric power market are elaborated in this paper, based on the data of power production and demand in the first quarter 2001, and the present situation on power supply and demand is analyzed from multi aspects.展开更多
The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates (e.g., lower and upper limits of ...The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates (e.g., lower and upper limits of metabolic power output) present a method for elucidating the effects of ecological and evolutionary factors on the interface between physiology and life history in birds. In this paper we review variation in avian metabolic rates [basal metabolic rate (BMR; minimum normothermic metabolic rate), summit metabolic rate (Msum; maximal thermoregulatory metabolic rate), and maximal metabolic rate (MMR; maximal exercise metabolic rate)], the factors associated with this variation, the evidence for functional links between these metabolic traits, and the ecological and evolutionary significance of avian metabolic diversity. Both lower and upper limits to metabolic power production are phenotypically flexible traits, and vary in association with numerous ecological and evolutionary factors. For both inter- and intraspecific comparisons, lower and upper limits to metabolic power production are generally upregulated in response to energetically demanding conditions and downregulated when energetic demands are relaxed, or under conditions of energetic scarcity. Positive correlations have been documented between BMR, Msum and MMR in some, but not all studies on birds, providing partial support for the idea of a functional link between lower and upper limits to metabolic power production, but more intraspecific studies are needed to determine the robustness of this conclusion. Correlations between BMR and field metabolic rate (or daily energy expenditure) in birds are variable, suggesting that the linkage between these traits is subject to behavioral adjustment, and studies of the relationship between field and maximal metabolic rates are lacking. Our understanding of avian metabolic diversity would benefit from future studies of: (1) the functional and mechanistic links between lower and upper limits of metabolic power output; (2) the environmental and ecological cues driving phenotypically flexible metabolic responses, and how responses to such cues might impact population responses to climate change; (3) the shapes of metabolic reaction norms and their association with environmental variability; and (4) the relationship of metabolic variation to fitness, including studies of repeatability and heritability of minimum and maximum metabolic power output [Current Zoology 56 (6): 741-758, 2010].展开更多
In order to improve the energy efficiency, reduce the CO2 emission and decrease the cost, a cogenera- tion system for desalination water, heat and power production was studied in this paper. The superstructure of the ...In order to improve the energy efficiency, reduce the CO2 emission and decrease the cost, a cogenera- tion system for desalination water, heat and power production was studied in this paper. The superstructure of the cogeneration system consisted of a coal-based thermal power plant (TPP), a multi-stage flash desalination (MSF) module and reverse osmosis desalination (RO) module. For different demands of water, heat and power production, the corresponding optimal production structure was different. After reasonable simplification, the process model ot each unit was built. The economical model, including the unit investment, and operation and maintenance cost, was presented. By solving this non-linear programming (NLP) model, whose objective is to minimize the annual cost, an optimal cogeneration system can be obtained. Compared to separate production systems, the optimal system can reduce 16.1%-21.7% of the total annual cost. showing this design method was effective.展开更多
The forward gated-diode R-G current method is used to monitor the F-N stressing-induced interface traps of NMOSFET/SOI.This simp le and accurate experiment method can directly give the interface trap density i nduced...The forward gated-diode R-G current method is used to monitor the F-N stressing-induced interface traps of NMOSFET/SOI.This simp le and accurate experiment method can directly give the interface trap density i nduced by F-N stressing effect for characterizing the device's reliability.For the measured NMOS/SOI device with a body structure,an expected power-law relati onship as Δ N it - t 0 4 between the pure F-N stressing-indu ced interface trap density and the accumulated stressing time is obtained.展开更多
AIM: To investigate the electric and contractile mechanisms involved in the deranged function of the transposed stomach in relation to the course of the symptoms and the changes in contractile and electrical parameter...AIM: To investigate the electric and contractile mechanisms involved in the deranged function of the transposed stomach in relation to the course of the symptoms and the changes in contractile and electrical parameters over time.METHODS: Twenty-one patients after subtotal esophagectomy and 18 healthy volunteers were studied.Complaints were compiled by using a questionnaire, and a symptom score was formed. Synchronous electrogastrography and gastric manometry were performed in the fasting state and postprandially.RESULTS: Eight of the operated patients were symptomfree and 13 had symptoms. The durations of the postoperative periods for the symptomatic (9.1±6.5 mo)and the asymptomatic (28.3±8.8 mo) patients were significantly different. The symptom score correlated negatively with the time that had elapsed since the operation. The percentages of the dominant frequency in the normogastric, bradygastric and tachygastric ranges differed significantly between the controls and the patients.A significant difference was detected between the power ratio of the controls and that of the patients. The occurrence of tachygastria in the symptomatic and the symptom-free patients correlated negatively both with the time that had elapsed and with the symptom score. There was a significant increase in motility index after feeding in the controls, but not in the patients. The contractile activity of the stomach increased both in the controls and in the symptom-free patients. In contrast, in the group of symptomatic patients, the contractile activity decreased postprandially as compared with the fasting state.CONCLUSION: The patients' post-operative complaints and symptoms change during the post-operative period and correlate with the parameters of the myoelectric and contractile activities of the stomach. Tachygastria seems to be the major pathogenetic factor involved in the contractile dysfunction.展开更多
This paper proposes a new channel access algorithm based on channel occupancy time (COT) fairness to guarantee fairness and improve the aggregate throughput of 802.11b multi-rate WLANs. In the algorithm, the COT is ...This paper proposes a new channel access algorithm based on channel occupancy time (COT) fairness to guarantee fairness and improve the aggregate throughput of 802.11b multi-rate WLANs. In the algorithm, the COT is used as fairness index to analyze the fairness of WLANs instead of the channel access probability (CAP) used in the distributed coordination function (DCF). The standard COT is given by access point (AP) and broadcasted to all wireless stations. The AP and wireless stations in the WLAN can achieve COT-based fairness by adjusting their packet length, sending the multiple back-to-back packets at one time, or giving up an opportunity to access the channel. Analysis and simulations show that our algorithm can provide COT-fairness. Compared with the CAP-based algorithm, the proposed algorithm leads to improvements in aggregate throughput of IEEE 802. lib multi-rate WLANs.展开更多
The incidence chromatic number of G is the least number of colors such that G has an incidence coloring. It is proved that the incidence chromatic number of Cn^p, the p-th power of the circuit graph, is 2p + 1 if and...The incidence chromatic number of G is the least number of colors such that G has an incidence coloring. It is proved that the incidence chromatic number of Cn^p, the p-th power of the circuit graph, is 2p + 1 if and only if n = k(2p + 1), for other cases: its incidence chromatic number is at most 2p + [r/k] + 2, where n = k(p + 1) + r, k is a positive integer. This upper bound is tight for some cases.展开更多
The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen e...The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen electrolytic cell equipped with an electrostatic-induction potential-superposed water electrolytic cell that provides a stoichiometric H2-O2 fuel mixture during operation of the vehicle. This generator functions with zero power input, zero matter input and zero emission due to the so-called "zero power input" electrostatic-to-chemical energy conversion occurring in the electrolytic cell. Here, theoretical simulations were performed to verify the target performance of such generators, assuming a pair of FC (fuel cell) and electrolytic cell stacks, both of which are commercially available.展开更多
The state-of-the-art solar power system technologies are presented. Various methods of capturing solar energy using solar collectors such as parabolic trough collectors and dish collectors are reviewed. Combined heat ...The state-of-the-art solar power system technologies are presented. Various methods of capturing solar energy using solar collectors such as parabolic trough collectors and dish collectors are reviewed. Combined heat and power (CHP) systems driven by concentrating solar absorbers and supplemented by biomass boilers are proving to be the most promising methods of domestic power generation, μCHP systems eliminate losses associated with power distribution and transmission opposed to the large scale power generation methods. The systems can utilize about 75% of solar energy to provide electric and thermal energy direct to end users. The driving potential behind μCHP systems is the thermal efficiency the systems can achieve and their market significance. Despite huge potential market for μCHP systems, the systems are yet to be seen available in commercial market. Hence the authors of this paper are currently developing such type of CHP system with electricity production being of prime importance.展开更多
The paper presents a method of life cycle assessment (LCA) to determine the impact of the electricity produced on the environment. To determine the environmental burdens and benefits the LCA technique is used, metho...The paper presents a method of life cycle assessment (LCA) to determine the impact of the electricity produced on the environment. To determine the environmental burdens and benefits the LCA technique is used, methodologically based on ISO 14040 series. In addition, the usefulness of this method to assess the energy sector has been shown. To evaluate the process, SimaPro software and the method of Eco Indicator 99 were used, which allows to get the results of the burden and benefit with taking into account three categories of damages: ecosystem quality, human health, and raw materials. This paper presents the impact of electricity generation on the environment in coal power plants. The article also points to the directions of the Polish energy sector and pointed to the need to determine the environmental risks associated with the production of energy. A detailed analysis by the method of LCA is made to compare the environmental impact of electricity generation in the Lagisza Power Plant and Turdw Power Plant. It is pointed to the difference in the results obtained. Moreover, the causes of the reported environmental impacts are discussed. Measures are identified which will help to reduce in the future the impact of the electricity produced on the environment during the production of electricity.展开更多
A microbial fuel cell (MFC) is a device that converts chemical energy to electrical energy during substrate oxidation by microorganisms. The characterization and identification of these microbial communities will al...A microbial fuel cell (MFC) is a device that converts chemical energy to electrical energy during substrate oxidation by microorganisms. The characterization and identification of these microbial communities will allow better control of this electricity generation with simultaneous removal of carbon and nitrogen. This study aims to investigate the role of natural bacteria in electricity generation by studying three different sources of wastewater: the raw wastewater (RW), wastewater from an aeration tank (AEW) and returned activated sludge (RAS) from an activated sludge treatment plant. The result showed that after the MFC treatment, the number of bacterial strains was reduced from twenty strains to eight strains. Microscopic observation further showed that fifteen isolate before the treatment were gram-positive, and five were gram-negative whereas all isolates after the treatment were gram-positive rods or cocci The four strains isolated from the RAS inoculums, β-Comamonas sp., γ-Enterobacter sp., Bacillus cereus sp. and Clostridium sp. produced the highest power density of 67.57 mW/m^2 which made them potential candidates for electrochemically active bacteria in MFCs. However, the level of chemical oxygen demand (COD) removal was 20% and the total kjeldahl nitrogen (TKN) removal was 66.7%. Key words:展开更多
The development of small and medium wind turbine industry in 2010 is presented, including the production capability, the mainstream products and the main producers. Suggestions for future's development are also pu...The development of small and medium wind turbine industry in 2010 is presented, including the production capability, the mainstream products and the main producers. Suggestions for future's development are also put forward.展开更多
On the basis of summing up the development of electric power industry in the 10th Five-Year Plan period, the idea of electric power development planning from 2006 to 2020 is presented. The authors analyzed ten main pr...On the basis of summing up the development of electric power industry in the 10th Five-Year Plan period, the idea of electric power development planning from 2006 to 2020 is presented. The authors analyzed ten main problems that existed in electric development during the 10th Five-Year Plan period, forecasted the electricity generation from 2006 to 2020, put forward the development strategy of power industry, discussed the component and development program of hydropower, thermal power, nuclear power, natural gas power and renewable power, outlined the present situations of six regional power grids, power transmission from western to eastern regions, UHV AC/DC power transmission and nationwide power grid interconnections, and finally gave out seven suggestions about electric power development in the future.展开更多
The exclusive use of renewable energies is today an essential nautical concern. Nowadays, the onboard energy generation comes mainly from diesel oil, which is in user mind the simplest way. Our objective is to develop...The exclusive use of renewable energies is today an essential nautical concern. Nowadays, the onboard energy generation comes mainly from diesel oil, which is in user mind the simplest way. Our objective is to develop a self-adaptive management system of the onboard energy in order to change the user mind. We introduce models for energy production, storage and consumption that fit with the yachting environment, which is mobile and not as predictable as the home automation case. These models are combined within a configurable simulator. This simulator can handle user's boat equipment, reproduce sailing conditions and so help to validate the models and to study different management strategies. This first step is necessary to develop a smart system able to manage sailing energy in order to answer the main issue: assuring safety and optimizing comfort according to user demands.展开更多
文摘The reverse generation current under high-gate-voltage stress condition in LDD nMOSFET's is studied. We find that the generation current peak decreases as the stress time increases. We ascribe this finding to the dominating oxide trapped electrons that reduce the effective drain bias, lowering the maximal generation rate. The density of the effective trapped electrons affecting the effective drain bias is calculated with our model.
文摘The supply and demand features of China electric power market are elaborated in this paper, based on the data of power production and demand in the first quarter 2001, and the present situation on power supply and demand is analyzed from multi aspects.
文摘The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates (e.g., lower and upper limits of metabolic power output) present a method for elucidating the effects of ecological and evolutionary factors on the interface between physiology and life history in birds. In this paper we review variation in avian metabolic rates [basal metabolic rate (BMR; minimum normothermic metabolic rate), summit metabolic rate (Msum; maximal thermoregulatory metabolic rate), and maximal metabolic rate (MMR; maximal exercise metabolic rate)], the factors associated with this variation, the evidence for functional links between these metabolic traits, and the ecological and evolutionary significance of avian metabolic diversity. Both lower and upper limits to metabolic power production are phenotypically flexible traits, and vary in association with numerous ecological and evolutionary factors. For both inter- and intraspecific comparisons, lower and upper limits to metabolic power production are generally upregulated in response to energetically demanding conditions and downregulated when energetic demands are relaxed, or under conditions of energetic scarcity. Positive correlations have been documented between BMR, Msum and MMR in some, but not all studies on birds, providing partial support for the idea of a functional link between lower and upper limits to metabolic power production, but more intraspecific studies are needed to determine the robustness of this conclusion. Correlations between BMR and field metabolic rate (or daily energy expenditure) in birds are variable, suggesting that the linkage between these traits is subject to behavioral adjustment, and studies of the relationship between field and maximal metabolic rates are lacking. Our understanding of avian metabolic diversity would benefit from future studies of: (1) the functional and mechanistic links between lower and upper limits of metabolic power output; (2) the environmental and ecological cues driving phenotypically flexible metabolic responses, and how responses to such cues might impact population responses to climate change; (3) the shapes of metabolic reaction norms and their association with environmental variability; and (4) the relationship of metabolic variation to fitness, including studies of repeatability and heritability of minimum and maximum metabolic power output [Current Zoology 56 (6): 741-758, 2010].
基金Supported by the National Natural Science Foundation of China(21076202)
文摘In order to improve the energy efficiency, reduce the CO2 emission and decrease the cost, a cogenera- tion system for desalination water, heat and power production was studied in this paper. The superstructure of the cogeneration system consisted of a coal-based thermal power plant (TPP), a multi-stage flash desalination (MSF) module and reverse osmosis desalination (RO) module. For different demands of water, heat and power production, the corresponding optimal production structure was different. After reasonable simplification, the process model ot each unit was built. The economical model, including the unit investment, and operation and maintenance cost, was presented. By solving this non-linear programming (NLP) model, whose objective is to minimize the annual cost, an optimal cogeneration system can be obtained. Compared to separate production systems, the optimal system can reduce 16.1%-21.7% of the total annual cost. showing this design method was effective.
文摘The forward gated-diode R-G current method is used to monitor the F-N stressing-induced interface traps of NMOSFET/SOI.This simp le and accurate experiment method can directly give the interface trap density i nduced by F-N stressing effect for characterizing the device's reliability.For the measured NMOS/SOI device with a body structure,an expected power-law relati onship as Δ N it - t 0 4 between the pure F-N stressing-indu ced interface trap density and the accumulated stressing time is obtained.
文摘AIM: To investigate the electric and contractile mechanisms involved in the deranged function of the transposed stomach in relation to the course of the symptoms and the changes in contractile and electrical parameters over time.METHODS: Twenty-one patients after subtotal esophagectomy and 18 healthy volunteers were studied.Complaints were compiled by using a questionnaire, and a symptom score was formed. Synchronous electrogastrography and gastric manometry were performed in the fasting state and postprandially.RESULTS: Eight of the operated patients were symptomfree and 13 had symptoms. The durations of the postoperative periods for the symptomatic (9.1±6.5 mo)and the asymptomatic (28.3±8.8 mo) patients were significantly different. The symptom score correlated negatively with the time that had elapsed since the operation. The percentages of the dominant frequency in the normogastric, bradygastric and tachygastric ranges differed significantly between the controls and the patients.A significant difference was detected between the power ratio of the controls and that of the patients. The occurrence of tachygastria in the symptomatic and the symptom-free patients correlated negatively both with the time that had elapsed and with the symptom score. There was a significant increase in motility index after feeding in the controls, but not in the patients. The contractile activity of the stomach increased both in the controls and in the symptom-free patients. In contrast, in the group of symptomatic patients, the contractile activity decreased postprandially as compared with the fasting state.CONCLUSION: The patients' post-operative complaints and symptoms change during the post-operative period and correlate with the parameters of the myoelectric and contractile activities of the stomach. Tachygastria seems to be the major pathogenetic factor involved in the contractile dysfunction.
基金Supported by National Natural Science Foundation of China (No.60472078 and No.90604013) .
文摘This paper proposes a new channel access algorithm based on channel occupancy time (COT) fairness to guarantee fairness and improve the aggregate throughput of 802.11b multi-rate WLANs. In the algorithm, the COT is used as fairness index to analyze the fairness of WLANs instead of the channel access probability (CAP) used in the distributed coordination function (DCF). The standard COT is given by access point (AP) and broadcasted to all wireless stations. The AP and wireless stations in the WLAN can achieve COT-based fairness by adjusting their packet length, sending the multiple back-to-back packets at one time, or giving up an opportunity to access the channel. Analysis and simulations show that our algorithm can provide COT-fairness. Compared with the CAP-based algorithm, the proposed algorithm leads to improvements in aggregate throughput of IEEE 802. lib multi-rate WLANs.
基金Supported by NSFC(10201022,10571124,10726008)Supported by SRCPBMCE(KM200610028002)Supported by BNSF(1012003)
文摘The incidence chromatic number of G is the least number of colors such that G has an incidence coloring. It is proved that the incidence chromatic number of Cn^p, the p-th power of the circuit graph, is 2p + 1 if and only if n = k(2p + 1), for other cases: its incidence chromatic number is at most 2p + [r/k] + 2, where n = k(p + 1) + r, k is a positive integer. This upper bound is tight for some cases.
文摘The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen electrolytic cell equipped with an electrostatic-induction potential-superposed water electrolytic cell that provides a stoichiometric H2-O2 fuel mixture during operation of the vehicle. This generator functions with zero power input, zero matter input and zero emission due to the so-called "zero power input" electrostatic-to-chemical energy conversion occurring in the electrolytic cell. Here, theoretical simulations were performed to verify the target performance of such generators, assuming a pair of FC (fuel cell) and electrolytic cell stacks, both of which are commercially available.
文摘The state-of-the-art solar power system technologies are presented. Various methods of capturing solar energy using solar collectors such as parabolic trough collectors and dish collectors are reviewed. Combined heat and power (CHP) systems driven by concentrating solar absorbers and supplemented by biomass boilers are proving to be the most promising methods of domestic power generation, μCHP systems eliminate losses associated with power distribution and transmission opposed to the large scale power generation methods. The systems can utilize about 75% of solar energy to provide electric and thermal energy direct to end users. The driving potential behind μCHP systems is the thermal efficiency the systems can achieve and their market significance. Despite huge potential market for μCHP systems, the systems are yet to be seen available in commercial market. Hence the authors of this paper are currently developing such type of CHP system with electricity production being of prime importance.
文摘The paper presents a method of life cycle assessment (LCA) to determine the impact of the electricity produced on the environment. To determine the environmental burdens and benefits the LCA technique is used, methodologically based on ISO 14040 series. In addition, the usefulness of this method to assess the energy sector has been shown. To evaluate the process, SimaPro software and the method of Eco Indicator 99 were used, which allows to get the results of the burden and benefit with taking into account three categories of damages: ecosystem quality, human health, and raw materials. This paper presents the impact of electricity generation on the environment in coal power plants. The article also points to the directions of the Polish energy sector and pointed to the need to determine the environmental risks associated with the production of energy. A detailed analysis by the method of LCA is made to compare the environmental impact of electricity generation in the Lagisza Power Plant and Turdw Power Plant. It is pointed to the difference in the results obtained. Moreover, the causes of the reported environmental impacts are discussed. Measures are identified which will help to reduce in the future the impact of the electricity produced on the environment during the production of electricity.
文摘A microbial fuel cell (MFC) is a device that converts chemical energy to electrical energy during substrate oxidation by microorganisms. The characterization and identification of these microbial communities will allow better control of this electricity generation with simultaneous removal of carbon and nitrogen. This study aims to investigate the role of natural bacteria in electricity generation by studying three different sources of wastewater: the raw wastewater (RW), wastewater from an aeration tank (AEW) and returned activated sludge (RAS) from an activated sludge treatment plant. The result showed that after the MFC treatment, the number of bacterial strains was reduced from twenty strains to eight strains. Microscopic observation further showed that fifteen isolate before the treatment were gram-positive, and five were gram-negative whereas all isolates after the treatment were gram-positive rods or cocci The four strains isolated from the RAS inoculums, β-Comamonas sp., γ-Enterobacter sp., Bacillus cereus sp. and Clostridium sp. produced the highest power density of 67.57 mW/m^2 which made them potential candidates for electrochemically active bacteria in MFCs. However, the level of chemical oxygen demand (COD) removal was 20% and the total kjeldahl nitrogen (TKN) removal was 66.7%. Key words:
文摘The development of small and medium wind turbine industry in 2010 is presented, including the production capability, the mainstream products and the main producers. Suggestions for future's development are also put forward.
文摘On the basis of summing up the development of electric power industry in the 10th Five-Year Plan period, the idea of electric power development planning from 2006 to 2020 is presented. The authors analyzed ten main problems that existed in electric development during the 10th Five-Year Plan period, forecasted the electricity generation from 2006 to 2020, put forward the development strategy of power industry, discussed the component and development program of hydropower, thermal power, nuclear power, natural gas power and renewable power, outlined the present situations of six regional power grids, power transmission from western to eastern regions, UHV AC/DC power transmission and nationwide power grid interconnections, and finally gave out seven suggestions about electric power development in the future.
文摘The exclusive use of renewable energies is today an essential nautical concern. Nowadays, the onboard energy generation comes mainly from diesel oil, which is in user mind the simplest way. Our objective is to develop a self-adaptive management system of the onboard energy in order to change the user mind. We introduce models for energy production, storage and consumption that fit with the yachting environment, which is mobile and not as predictable as the home automation case. These models are combined within a configurable simulator. This simulator can handle user's boat equipment, reproduce sailing conditions and so help to validate the models and to study different management strategies. This first step is necessary to develop a smart system able to manage sailing energy in order to answer the main issue: assuring safety and optimizing comfort according to user demands.