EMBROIDERY is a very precious traditional handicraft in China. Over a century ago it came into daily use for Chinese people. The bridal chamber of every ordinary couple was filled with embroidery, on the bed curtain, ...EMBROIDERY is a very precious traditional handicraft in China. Over a century ago it came into daily use for Chinese people. The bridal chamber of every ordinary couple was filled with embroidery, on the bed curtain, pillow case and quilt covers, stitched with auspicious dragons展开更多
The Songliao basin is a complex successor basin that was initiated in the Mesozoic and experienced multiple periods of reactivation. Based on seismic and drilling data, as well as regional geologic research, we sugges...The Songliao basin is a complex successor basin that was initiated in the Mesozoic and experienced multiple periods of reactivation. Based on seismic and drilling data, as well as regional geologic research, we suggest that the Songliao basin contains several different successor basins resting on top of Carboniferous-Permian folded strata forming the basement to the Songliao basin. These basins include the Triassic-Mid Jurassic Paleo-foreland basin, the Late Jurassic-Early Cretaceous downfaulted basin, and an early Cretaceous depressed basin （since the Denglouku Group）. This paper presents a systematic study of the basin-mountain interactions, and reveals that there are different types of prototype basin at different geologic times. These prototype basins sequentially superimposed and formed the large Songliao basin. Discovery of the Triassic-early Middle Jurassic paleo-foreland basin fills a Triassic-early Middle Jurassic gap in the geologic history of the Songliao basin. The paleo- foreland basin, downfaulted basin, and depressed thermal subsidence basin all together represent the whole Mesozoic-Cenozoic geologic history and deformation of the Songliao basin. Discovery of the Triassic-early Middle Jurassic paleo-foreland basin plays an important role both for deep natural gas exploration and the study of basin-mountain coupling in north China and eastern China in general. This example gives dramatic evidence that we should give much more attention to the polyphase tectonic evolution of related basins for the next phase of exploration and study.展开更多
In multi-agent reinforcement learning(MARL),the behaviors of each agent can influence the learning of others,and the agents have to search in an exponentially enlarged joint-action space.Hence,it is challenging for th...In multi-agent reinforcement learning(MARL),the behaviors of each agent can influence the learning of others,and the agents have to search in an exponentially enlarged joint-action space.Hence,it is challenging for the multi-agent teams to explore in the environment.Agents may achieve suboptimal policies and fail to solve some complex tasks.To improve the exploring efficiency as well as the performance of MARL tasks,in this paper,we propose a new approach by transferring the knowledge across tasks.Differently from the traditional MARL algorithms,we first assume that the reward functions can be computed by linear combinations of a shared feature function and a set of taskspecific weights.Then,we define a set of basic MARL tasks in the source domain and pre-train them as the basic knowledge for further use.Finally,once the weights for target tasks are available,it will be easier to get a well-performed policy to explore in the target domain.Hence,the learning process of agents for target tasks is speeded up by taking full use of the basic knowledge that was learned previously.We evaluate the proposed algorithm on two challenging MARL tasks:cooperative boxpushing and non-monotonic predator-prey.The experiment results have demonstrated the improved performance compared with state-of-the-art MARL algorithms.展开更多
Combined with real engineering, we mainly study the stability of the equilibrium state at the coordinate center of an orthotropic stringer shell system, and the approximate analytic periodic motion is presented around...Combined with real engineering, we mainly study the stability of the equilibrium state at the coordinate center of an orthotropic stringer shell system, and the approximate analytic periodic motion is presented around the studied equilibrium state. In addition the rationality of the obtained results is verified by numerical simulation. Furthermore we found that there are actually only four kinds of phase portrait of this type of shell.展开更多
Voyagers,the first and the only mission sent by human beings beyond the end of the solar wind,might be out of service in just several years.In the cosmos beyond 2025,very likely no artificial detector will be flying a...Voyagers,the first and the only mission sent by human beings beyond the end of the solar wind,might be out of service in just several years.In the cosmos beyond 2025,very likely no artificial detector will be flying at the outer brim of the solar system.The Interstellar Express,a mission proposed by CAS scientists,might come timely as a possible successor to fill in the gap.Unlike Voyagers,its detectors are expected to fly not only to the nose part of the heliosphere,but also the tail part and the altitude dimension.As planned in the shortterm stage of its three-step layout,the first two detectors will be launched by the end of 2025,if everything goes well.展开更多
In this paper,three competitive systems with different kinds of state-dependent control are presented and investigated.The existence of the order-1 homoclinic orbit and order-1 periodic solution of the two systems tha...In this paper,three competitive systems with different kinds of state-dependent control are presented and investigated.The existence of the order-1 homoclinic orbit and order-1 periodic solution of the two systems that incorporate just one kind of state-dependent control is obtained by applying differential equation geometry theory,and the stability of the order-1 periodic solution of each system is also given.Besides,sufficient conditions for the existence and stability of the order-2 periodic solution of the system that incorporate two kinds of state-dependent control are gained by successor function method and analogue of Poincare criterion,respectively.Finally,numerical simulations are carried out to verify the theoretical results.展开更多
In this paper,the system with impulsive state feedback control corresponding to the sulphitation reaction in process of manufacturo of sugar is considered.By means of square approximation and a series of switched syst...In this paper,the system with impulsive state feedback control corresponding to the sulphitation reaction in process of manufacturo of sugar is considered.By means of square approximation and a series of switched systems,the periodic solution is approximated by a series of continuous hybrid limit cycles.Similar to the analysis of limit cycles of continuous systems,the existence and stability criteria of the order-1 periodic solution are obtained.Further,numerical analysis and discussion are given.展开更多
The price fluctuation of commodities affects their demand,and it strongly influences the development of industry and the stability of the international economy.A price-output model with two price-dependent impulses is...The price fluctuation of commodities affects their demand,and it strongly influences the development of industry and the stability of the international economy.A price-output model with two price-dependent impulses is presented in this paper to describe their mutual restrictions and the price adjustment strategies.The equilibria and dynamic properties of the impulsive-free price-output model are qualitatively analyzed,and the results show the hazard of free price fluctuation.For the price-output model with two price-dependent impulses,conditions for the existence of the order-2 periodic solution are obtained,and the orbital asymptotic stability is proved.Those results reveal the positive role of price adjustment strategies.Finally,some numerical simulations are carried out to verify the theoretical results.展开更多
文摘EMBROIDERY is a very precious traditional handicraft in China. Over a century ago it came into daily use for Chinese people. The bridal chamber of every ordinary couple was filled with embroidery, on the bed curtain, pillow case and quilt covers, stitched with auspicious dragons
基金the National Natural Science Foundation of China （Nos. 40573002, 40773030, 40373005） ； Sichuan Province Science Foundation （Nos. 03ZQ026-046, 05JY029-088-2）.
文摘The Songliao basin is a complex successor basin that was initiated in the Mesozoic and experienced multiple periods of reactivation. Based on seismic and drilling data, as well as regional geologic research, we suggest that the Songliao basin contains several different successor basins resting on top of Carboniferous-Permian folded strata forming the basement to the Songliao basin. These basins include the Triassic-Mid Jurassic Paleo-foreland basin, the Late Jurassic-Early Cretaceous downfaulted basin, and an early Cretaceous depressed basin （since the Denglouku Group）. This paper presents a systematic study of the basin-mountain interactions, and reveals that there are different types of prototype basin at different geologic times. These prototype basins sequentially superimposed and formed the large Songliao basin. Discovery of the Triassic-early Middle Jurassic paleo-foreland basin fills a Triassic-early Middle Jurassic gap in the geologic history of the Songliao basin. The paleo- foreland basin, downfaulted basin, and depressed thermal subsidence basin all together represent the whole Mesozoic-Cenozoic geologic history and deformation of the Songliao basin. Discovery of the Triassic-early Middle Jurassic paleo-foreland basin plays an important role both for deep natural gas exploration and the study of basin-mountain coupling in north China and eastern China in general. This example gives dramatic evidence that we should give much more attention to the polyphase tectonic evolution of related basins for the next phase of exploration and study.
基金the National Key R&D Program of China(2021ZD0112700,2018AAA0101400)the National Natural Science Foundation of China(62173251,61921004,U1713209)the Natural Science Foundation of Jiangsu Province of China(BK20202006)。
文摘In multi-agent reinforcement learning(MARL),the behaviors of each agent can influence the learning of others,and the agents have to search in an exponentially enlarged joint-action space.Hence,it is challenging for the multi-agent teams to explore in the environment.Agents may achieve suboptimal policies and fail to solve some complex tasks.To improve the exploring efficiency as well as the performance of MARL tasks,in this paper,we propose a new approach by transferring the knowledge across tasks.Differently from the traditional MARL algorithms,we first assume that the reward functions can be computed by linear combinations of a shared feature function and a set of taskspecific weights.Then,we define a set of basic MARL tasks in the source domain and pre-train them as the basic knowledge for further use.Finally,once the weights for target tasks are available,it will be easier to get a well-performed policy to explore in the target domain.Hence,the learning process of agents for target tasks is speeded up by taking full use of the basic knowledge that was learned previously.We evaluate the proposed algorithm on two challenging MARL tasks:cooperative boxpushing and non-monotonic predator-prey.The experiment results have demonstrated the improved performance compared with state-of-the-art MARL algorithms.
文摘Combined with real engineering, we mainly study the stability of the equilibrium state at the coordinate center of an orthotropic stringer shell system, and the approximate analytic periodic motion is presented around the studied equilibrium state. In addition the rationality of the obtained results is verified by numerical simulation. Furthermore we found that there are actually only four kinds of phase portrait of this type of shell.
文摘Voyagers,the first and the only mission sent by human beings beyond the end of the solar wind,might be out of service in just several years.In the cosmos beyond 2025,very likely no artificial detector will be flying at the outer brim of the solar system.The Interstellar Express,a mission proposed by CAS scientists,might come timely as a possible successor to fill in the gap.Unlike Voyagers,its detectors are expected to fly not only to the nose part of the heliosphere,but also the tail part and the altitude dimension.As planned in the shortterm stage of its three-step layout,the first two detectors will be launched by the end of 2025,if everything goes well.
基金The authors would like to thank the anonymous referees and Professor Lansun Chen for their very valuable comments,which led to a significant improveinent of the original paper.This work is supposed by the National Natural Science Foundation of China(No.11671346)Nanhu Scholars Program of XYNU.
文摘In this paper,three competitive systems with different kinds of state-dependent control are presented and investigated.The existence of the order-1 homoclinic orbit and order-1 periodic solution of the two systems that incorporate just one kind of state-dependent control is obtained by applying differential equation geometry theory,and the stability of the order-1 periodic solution of each system is also given.Besides,sufficient conditions for the existence and stability of the order-2 periodic solution of the system that incorporate two kinds of state-dependent control are gained by successor function method and analogue of Poincare criterion,respectively.Finally,numerical simulations are carried out to verify the theoretical results.
基金This work is supported by the National Natural Science Foundation of China(61751317)the Natural Science Foundation of Guangxi Province(2018JJA110058,2019JJA110027)the Scientific Research Fund of Yulin Normal University for High-level Talents(G2019ZK18).
文摘In this paper,the system with impulsive state feedback control corresponding to the sulphitation reaction in process of manufacturo of sugar is considered.By means of square approximation and a series of switched systems,the periodic solution is approximated by a series of continuous hybrid limit cycles.Similar to the analysis of limit cycles of continuous systems,the existence and stability criteria of the order-1 periodic solution are obtained.Further,numerical analysis and discussion are given.
基金This work is supported by the National Natural Science Foundation of China(No.11701026,No.12071407)the Fundaineiital Researcli Funds of Beijing University of Civil Engineering and Architecture(No.X18225,No.XI9031)the Post Graduate Innovation Project of Beijing University of Civil Engineering and Architecture(No.PG2020098).
文摘The price fluctuation of commodities affects their demand,and it strongly influences the development of industry and the stability of the international economy.A price-output model with two price-dependent impulses is presented in this paper to describe their mutual restrictions and the price adjustment strategies.The equilibria and dynamic properties of the impulsive-free price-output model are qualitatively analyzed,and the results show the hazard of free price fluctuation.For the price-output model with two price-dependent impulses,conditions for the existence of the order-2 periodic solution are obtained,and the orbital asymptotic stability is proved.Those results reveal the positive role of price adjustment strategies.Finally,some numerical simulations are carried out to verify the theoretical results.
