“双碳”背景下,随着碳捕集与封存技术逐步被应用于燃煤机组中,碳捕集-电转气(carbon capture-power to gas,CC-P2G)的耦合特性对电-气互联系统(integrated electricity and gas system,IEGS)安全可靠性的影响不可忽视。为评估该影响,...“双碳”背景下,随着碳捕集与封存技术逐步被应用于燃煤机组中,碳捕集-电转气(carbon capture-power to gas,CC-P2G)的耦合特性对电-气互联系统(integrated electricity and gas system,IEGS)安全可靠性的影响不可忽视。为评估该影响,基于耦合设备变工况精细化模型,提出了考虑CC-P2G耦合特性的IEGS连锁故障评估方法。首先,将电转气过程划分为电解水和甲烷化,并将碳捕集系统中的二氧化碳参与甲烷化,建立CC-P2G变工况精细化模型;同时,考虑详细的气转电过程建立燃气轮机变工况精细化模型。然后,根据电能和天然气流动惯性差异,分别建立基于直流潮流的电力系统连锁故障模型和基于动态潮流的天然气系统连锁故障模型,协同模拟IEGS连锁故障。最后,从拓扑完整性与物理运行特性角度建立评估指标,分别对电力系统与天然气系统受到的连锁故障影响进行量化评估。利用IEEE 39节点系统和29节点天然气系统构建电-气互联测试系统,验证所提方法的有效性。展开更多
多园区综合能源微电网系统交互需要解决每个微电网之间的协调优化调度的问题,文中通过引入交互耦合功率变量解耦的方法,来求解园区内微电网之间交互的电功率,将集中求解的复杂问题转换为各微电网之间相互合作而且可以内部管理的优化问题...多园区综合能源微电网系统交互需要解决每个微电网之间的协调优化调度的问题,文中通过引入交互耦合功率变量解耦的方法,来求解园区内微电网之间交互的电功率,将集中求解的复杂问题转换为各微电网之间相互合作而且可以内部管理的优化问题,于是文中考虑采用同步式交替向乘子法(alternating direction method of multipliers,ADMM)分布式求解方法来实现各个园区微电网系统的成本关系分配,系统只需要求解分布式优化方案所需的信息,可以最大限度地降低运行成本,同时为了保证多园区微电网系统的低碳运行和降低环境成本,在考虑单个电热冷综合能源微电网系统的基础上,采用碳捕集设备和电转气装置以及配合阶梯碳交易机制的方法,更进一步降低系统碳排放;最后,通过仿真算例来验证所提方法和模型的有效性。展开更多
The interaction of a single two-level two-mode trapped ion with a laser beam has been studied theoretically. With application of a unitary transformation, an analytical solution to this quantum system has been obtaine...The interaction of a single two-level two-mode trapped ion with a laser beam has been studied theoretically. With application of a unitary transformation, an analytical solution to this quantum system has been obtained without performing the Lamb-Dicke approximation. In this system the entangled displacement Fock state is produced.展开更多
We have reported previously the ultrafast energy transfer process with a time constant of 0.8 ps from a monomeric to a dimeric subunit within a perylenetetracarboxylic diimide trimer, which was derived indirectly from...We have reported previously the ultrafast energy transfer process with a time constant of 0.8 ps from a monomeric to a dimeric subunit within a perylenetetracarboxylic diimide trimer, which was derived indirectly from a model fitting into the transient absorption experimental data. Here we present a direct ultrafast fluorescence quenching measurement by employing fs time-resolved transient fluorescence spectroscopy based on noncollinear optical parametric amplification technique. The rapid decay of the monomer's emission due to energy transfer was observed directly with a time constant of about 0.82 ps, in good agreement with the previous result.展开更多
Nowadays,the upwind schemes are in a rapid development to capture shock accurately.However,these upwind schemes’properties at low speeds,such as their reconstruction scheme dependencies,grid dependencies,and Mach num...Nowadays,the upwind schemes are in a rapid development to capture shock accurately.However,these upwind schemes’properties at low speeds,such as their reconstruction scheme dependencies,grid dependencies,and Mach number dependencies,are concerned by few people.In this paper,a systematic study on their low speeds’issues is conducted.Through a series of tests,we can find that most parameter-free upwind schemes,widely used in practice today,are not applicable to low speeds’simulations.In contrast,SLAU and SLAU2 can give reliable results.Also,the upwind scheme’s influence on the accuracy is stronger than the reconstruction scheme’s influence at low speeds.展开更多
We study the effects of electrolyte temperature on DNA molecule translocation experimentally without and with a temperature gradient across nanopore membranes.The same temperatures on both electrolyte chambers are fir...We study the effects of electrolyte temperature on DNA molecule translocation experimentally without and with a temperature gradient across nanopore membranes.The same temperatures on both electrolyte chambers are first considered.The DNA molecule translocation time is measured to be 2.44 ms at 2°C in both chambers,which is 1.57 times longer than at 20°C.Then the temperature difference effect is characterized in both chambers.The results show that the DNA translocation speed can be slowed down as long as one side temperature is lowered,irrespective of the temperature gradient direction.This indicates that the thermophoretic driving force generated by a temperature gradient has no obvious effect on the threading speed of DNA molecules,while the main reason for the slowed DNA translocation speed is the increased viscosity.Interestingly,the capture rate of DNA molecules is enhanced under a temperature gradient condition,and the capture rate during DNA translocation from hot side at 21°C to cold one at 2°C is 1.7 times larger than that under the condition of both chambers at 20°C.Finally,an optimized configuration is proposed to acquire higher capture rates and lower DNA translocation speeds.展开更多
The impacts of transgenic Bt rice on target pests and their predators need to be clarified prior to the commercialization of Bt rice.In this study,the percentages of folded leaves of three transgenic Bt rice lines and...The impacts of transgenic Bt rice on target pests and their predators need to be clarified prior to the commercialization of Bt rice.In this study,the percentages of folded leaves of three transgenic Bt rice lines and non-transgenic parental rice line caused by Cnaphalocrocis medinalis were studied over two successive growing seasons.In addition,the population densities,relative abundance and population dynamics of C.medinalis and four species of its natural arthropod predators were investigated at three sites in China.The results showed that rice line significantly affected the percentages of folded leaves and population densities of C.medinalis larvae.Significantly higher percentages of folded leaves were observed on the non-transgenic rice compared with the three transgenic Bt rice on most sampling dates.Significantly higher densities of C.medinalis larvae and higher relative abundance of C.medinalis within phytophages were found on non-transgenic rice compared with three transgenic Bt rice at different sites across the study period.The population dynamics of C.medinalis larvae were significantly affected by rice line,rice line×sampling date,rice line×year,rice line×sampling date×year.However,there was little,if any,significant difference in the relative abundance,population density and population dynamics of the four arthropod predators between the three Bt rice lines and non-transgenic rice.The results of this study indicate that the Bt toxin in transgenic Bt rice can effectively suppress the occurrence of C.medinalis,but has no significant effects on the occurrence of the four predatory arthropod species.展开更多
In this paper the management model a two-species fishery involving impulsesis investigated by using optimal impulsive control theorem. Optimal impulsive harvesting times andthe corresponding optimal harvesting populat...In this paper the management model a two-species fishery involving impulsesis investigated by using optimal impulsive control theorem. Optimal impulsive harvesting times andthe corresponding optimal harvesting population levels in different cases are obtained.展开更多
The recognition and binding of proteins through the "fly-casting" mechanism are important biological processes. In this paper, a physical model for fly-casting binding is described based on the capillarity t...The recognition and binding of proteins through the "fly-casting" mechanism are important biological processes. In this paper, a physical model for fly-casting binding is described based on the capillarity theory for protein chains. It is found that the capture radius for the fly-casting binding process is maximized at the transition temperature at which the free energy of the monomeric extended state of the protein equals that of the folded state. The factors related to the folding barrier or binding affinity do not change the condition needed to realize the optimization for fly-casting processes. These results will aid in the comprehensive understanding of binding processes.展开更多
This paper proposed a novel model-based feature representation method to characterize human walking properties for individual recognition by gait. First, a new spatial point reconstruction approach is proposed to reco...This paper proposed a novel model-based feature representation method to characterize human walking properties for individual recognition by gait. First, a new spatial point reconstruction approach is proposed to recover the coordinates of 3D points from 2D images by the related coordinate conversion factor (CCF). The images are captured by a monocular camera. Second, the human body is represented by a connected three-stick model. Then the parameters of the body model are recovered by the method of projective geometry using the related CCF. Finally, the gait feature composed of those parameters is defined, and it is proved by experiments that those features can partially avoid the influence of viewing angles between the optical axis of the camera and walking direction of the subject.展开更多
文摘“双碳”背景下,随着碳捕集与封存技术逐步被应用于燃煤机组中,碳捕集-电转气(carbon capture-power to gas,CC-P2G)的耦合特性对电-气互联系统(integrated electricity and gas system,IEGS)安全可靠性的影响不可忽视。为评估该影响,基于耦合设备变工况精细化模型,提出了考虑CC-P2G耦合特性的IEGS连锁故障评估方法。首先,将电转气过程划分为电解水和甲烷化,并将碳捕集系统中的二氧化碳参与甲烷化,建立CC-P2G变工况精细化模型;同时,考虑详细的气转电过程建立燃气轮机变工况精细化模型。然后,根据电能和天然气流动惯性差异,分别建立基于直流潮流的电力系统连锁故障模型和基于动态潮流的天然气系统连锁故障模型,协同模拟IEGS连锁故障。最后,从拓扑完整性与物理运行特性角度建立评估指标,分别对电力系统与天然气系统受到的连锁故障影响进行量化评估。利用IEEE 39节点系统和29节点天然气系统构建电-气互联测试系统,验证所提方法的有效性。
文摘多园区综合能源微电网系统交互需要解决每个微电网之间的协调优化调度的问题,文中通过引入交互耦合功率变量解耦的方法,来求解园区内微电网之间交互的电功率,将集中求解的复杂问题转换为各微电网之间相互合作而且可以内部管理的优化问题,于是文中考虑采用同步式交替向乘子法(alternating direction method of multipliers,ADMM)分布式求解方法来实现各个园区微电网系统的成本关系分配,系统只需要求解分布式优化方案所需的信息,可以最大限度地降低运行成本,同时为了保证多园区微电网系统的低碳运行和降低环境成本,在考虑单个电热冷综合能源微电网系统的基础上,采用碳捕集设备和电转气装置以及配合阶梯碳交易机制的方法,更进一步降低系统碳排放;最后,通过仿真算例来验证所提方法和模型的有效性。
基金The project supported by the Natural Science Foundation of the Education Committee of Anhui Province of China under Grant No.2004kj186
文摘The interaction of a single two-level two-mode trapped ion with a laser beam has been studied theoretically. With application of a unitary transformation, an analytical solution to this quantum system has been obtained without performing the Lamb-Dicke approximation. In this system the entangled displacement Fock state is produced.
基金This work was supported by the National Natural Science Foundation of China (No.20925313 and No.60438020), the National Basic Research Program of China (No.2009CB929404), and the Chinese Academy of Sciences Innovation Program (KJCX2-YW-W25).
文摘We have reported previously the ultrafast energy transfer process with a time constant of 0.8 ps from a monomeric to a dimeric subunit within a perylenetetracarboxylic diimide trimer, which was derived indirectly from a model fitting into the transient absorption experimental data. Here we present a direct ultrafast fluorescence quenching measurement by employing fs time-resolved transient fluorescence spectroscopy based on noncollinear optical parametric amplification technique. The rapid decay of the monomer's emission due to energy transfer was observed directly with a time constant of about 0.82 ps, in good agreement with the previous result.
基金supported by the National Basic Research Program of China("973" Project)(Grant No.2009CB724104)
文摘Nowadays,the upwind schemes are in a rapid development to capture shock accurately.However,these upwind schemes’properties at low speeds,such as their reconstruction scheme dependencies,grid dependencies,and Mach number dependencies,are concerned by few people.In this paper,a systematic study on their low speeds’issues is conducted.Through a series of tests,we can find that most parameter-free upwind schemes,widely used in practice today,are not applicable to low speeds’simulations.In contrast,SLAU and SLAU2 can give reliable results.Also,the upwind scheme’s influence on the accuracy is stronger than the reconstruction scheme’s influence at low speeds.
基金supported by the National Basic Research Program of China("973"Project)(Grant Nos.2011CB707601 and 2011CB707605)the National Natural Science Foundation of China(Grants Nos.50925519 and 51375092)+1 种基金supported by the Scientific Research Foundation of Graduate School of Southeast University(Grant No.YBJJ1004)supported by the Fundamental Research Funds for the Central Universities and the Innovative Project for Graduate Students of Jiangsu Province(Grant No.KYLX_0100)
文摘We study the effects of electrolyte temperature on DNA molecule translocation experimentally without and with a temperature gradient across nanopore membranes.The same temperatures on both electrolyte chambers are first considered.The DNA molecule translocation time is measured to be 2.44 ms at 2°C in both chambers,which is 1.57 times longer than at 20°C.Then the temperature difference effect is characterized in both chambers.The results show that the DNA translocation speed can be slowed down as long as one side temperature is lowered,irrespective of the temperature gradient direction.This indicates that the thermophoretic driving force generated by a temperature gradient has no obvious effect on the threading speed of DNA molecules,while the main reason for the slowed DNA translocation speed is the increased viscosity.Interestingly,the capture rate of DNA molecules is enhanced under a temperature gradient condition,and the capture rate during DNA translocation from hot side at 21°C to cold one at 2°C is 1.7 times larger than that under the condition of both chambers at 20°C.Finally,an optimized configuration is proposed to acquire higher capture rates and lower DNA translocation speeds.
基金supported by National Genetically Modified Organisms Breeding Major Project:Technology of Environmental Risk Assessment on Transgenic Rice (Grant No. 2008ZX08011-001)
文摘The impacts of transgenic Bt rice on target pests and their predators need to be clarified prior to the commercialization of Bt rice.In this study,the percentages of folded leaves of three transgenic Bt rice lines and non-transgenic parental rice line caused by Cnaphalocrocis medinalis were studied over two successive growing seasons.In addition,the population densities,relative abundance and population dynamics of C.medinalis and four species of its natural arthropod predators were investigated at three sites in China.The results showed that rice line significantly affected the percentages of folded leaves and population densities of C.medinalis larvae.Significantly higher percentages of folded leaves were observed on the non-transgenic rice compared with the three transgenic Bt rice on most sampling dates.Significantly higher densities of C.medinalis larvae and higher relative abundance of C.medinalis within phytophages were found on non-transgenic rice compared with three transgenic Bt rice at different sites across the study period.The population dynamics of C.medinalis larvae were significantly affected by rice line,rice line×sampling date,rice line×year,rice line×sampling date×year.However,there was little,if any,significant difference in the relative abundance,population density and population dynamics of the four arthropod predators between the three Bt rice lines and non-transgenic rice.The results of this study indicate that the Bt toxin in transgenic Bt rice can effectively suppress the occurrence of C.medinalis,but has no significant effects on the occurrence of the four predatory arthropod species.
基金This research is supported by the Foundation of Educational Committee of Liaoning Province (No.20331080)
文摘In this paper the management model a two-species fishery involving impulsesis investigated by using optimal impulsive control theorem. Optimal impulsive harvesting times andthe corresponding optimal harvesting population levels in different cases are obtained.
基金supported by the National Basic Research Program of China (Grant No.2007CB814806)the National Natural Science Foundation of China (Grant Nos.10974088,10834002 and 10774069)the Natural Science Foundation of Jiangsu Province (Grant No.BK2009008)
文摘The recognition and binding of proteins through the "fly-casting" mechanism are important biological processes. In this paper, a physical model for fly-casting binding is described based on the capillarity theory for protein chains. It is found that the capture radius for the fly-casting binding process is maximized at the transition temperature at which the free energy of the monomeric extended state of the protein equals that of the folded state. The factors related to the folding barrier or binding affinity do not change the condition needed to realize the optimization for fly-casting processes. These results will aid in the comprehensive understanding of binding processes.
基金the National Natural Science Foundation of China (No. 60675024)
文摘This paper proposed a novel model-based feature representation method to characterize human walking properties for individual recognition by gait. First, a new spatial point reconstruction approach is proposed to recover the coordinates of 3D points from 2D images by the related coordinate conversion factor (CCF). The images are captured by a monocular camera. Second, the human body is represented by a connected three-stick model. Then the parameters of the body model are recovered by the method of projective geometry using the related CCF. Finally, the gait feature composed of those parameters is defined, and it is proved by experiments that those features can partially avoid the influence of viewing angles between the optical axis of the camera and walking direction of the subject.