A novel dynamic optical add-drop multiplexer(OADM) scheme using tunable sampled fiber Bragg gratings(SFBG) by Vernier effect is firstly proposed. In this scheme, broad wavelength tuning range is achieved by only sligh...A novel dynamic optical add-drop multiplexer(OADM) scheme using tunable sampled fiber Bragg gratings(SFBG) by Vernier effect is firstly proposed. In this scheme, broad wavelength tuning range is achieved by only slightly adjusting the SFBG, the wavelength tuning of OADM will be faster than traditional dynamic OADM.展开更多
We investigate an adaptive cooperative protocol in a Two-Hop-Relay (THR) wireless system that combines the following: (1) adaptive relaying based on repetition coding; (2) single or two transmit antennas and one recei...We investigate an adaptive cooperative protocol in a Two-Hop-Relay (THR) wireless system that combines the following: (1) adaptive relaying based on repetition coding; (2) single or two transmit antennas and one receive antenna configurations for all nodes, each using high order constellation; (3) Bit-Interleaved Coded Modulation (BICM). We focus on a simple decoded relaying (i.e. no error correcting at a relay node) and simple signal quality thresholds for relaying. Then the impact of the two simple thresholds on the system performance is studied. Our results suggest that compared with the traditional scheme for direct transmission, the proposed scheme can increase average throughput in high spectral efficiency region with low implementa-tion-cost at the relay.展开更多
The aim of this paper is to reveal the mechanism of compromise and change in coordination where players agree in general but disagree on coordination methods. When players agree on the need to collaborate but are in c...The aim of this paper is to reveal the mechanism of compromise and change in coordination where players agree in general but disagree on coordination methods. When players agree on the need to collaborate but are in conflict regarding the specific method, one player must always compromise. This situation is known as the Battle of the Sexes in game theory. It has ever been believed that if an agreement is reached under such circumstances, the players do not have the incentive to withdraw from the agreement. However, this study shows that this belief is not always true if the players were able to revise the outcome of their negotiations later. The wide-ranging fields use game theories for their analysis frameworks to analyze the success or failure of coordination. However, comparing with the possibility of betrayal illustrated as a well-known Prisoner Dilemma, it has been rare to discuss conflict regarding the specific method of coordination, although such situations are often observed in today＇s interdependent real world. The repeated Battle of the Sexes games presented in this study would be a useful framework to analyze conflict regarding the specific method of coordination.展开更多
The performances of nonlinear WDM systems with different duty cycle are compared by means of numerical simulation.The numerical results show that the optical pulse with duty cycle of 0.5 is superior to the conventiona...The performances of nonlinear WDM systems with different duty cycle are compared by means of numerical simulation.The numerical results show that the optical pulse with duty cycle of 0.5 is superior to the conventional NRZ modulation scheme.The conclusion is different from that of some references.The reason is that inter symbol interference is not included in some references.In fact,inter symbol interference plays an important role in nonlinear WDM system.Although the larger the duty cycle is ,the stronger the effect of the cross-phase modulation and self-phase modulation on nonlinear WDM is,however,the larger the duty cycle is,the stronger the inter symbol interference is.展开更多
Laszlo and Olsson constructed Grothendieck＇s six operations for constructible complexes on Artin stacks in etale cohomology under an assumption of finite cohomological dimension, with base change established on the l...Laszlo and Olsson constructed Grothendieck＇s six operations for constructible complexes on Artin stacks in etale cohomology under an assumption of finite cohomological dimension, with base change established on the level of sheaves. We give a more direct construction of the six operations for complexes on Deligne- Mumford stacks without the finiteness assumption and establish base change theorems in derived categories. One key tool in our construction is the theory of gluing finitely many pseudofunctors developed by Zheng （2014）. As an application, we prove a Lefschetz-Verdier formula for Deligne-Mumford stacks. We include both torsion and l-adic coefficients.展开更多
Self-healing materials have attracted considerable attention because of their improved safety, lifetime, energy efficiency and environmental impact. Supramolecular interactions have been extensively considered in the ...Self-healing materials have attracted considerable attention because of their improved safety, lifetime, energy efficiency and environmental impact. Supramolecular interactions have been extensively considered in the field of self-healing materials due to their excellent reversibility and sensitive responsiveness to environmental stimuli. However,development of a polymeric material with good mechanical performance as well as self-healing capacity is very challenging. In this study, we report a robust self-healing polyurethane(PU) elastomer polypropylene glycol-2-amino-5-(2-hydroxyethyl)-6-methylpyrimidin-4-ol(PPG-mUPy) by integrating ureidopyrimidone(UPy) motifs with a PPG segment with a well-defined architecture and microphase morphology.To balance the self-healing capacity and mechanical performance, a thermal-triggered switch of H-bonding is introduced. The quadruple H-bonded UPy dimeric moieties in the backbone induce phase separation to form a hard domain as well as enable further aggregation into microcrystals by virtue of the stacking interactions, which are stable in ambient temperature. This feature endows the PU with high mechanical strength. Meanwhile, a high healing efficiency can be realized, when the reversibility of the H-bond was unlocked from the stacking at higher temperature. An optimized sample PPG1000-mUPy50%with a good balance of mechanical performance(20.62 MPa of tensile strength) and healing efficiency(93% in tensile strength) was achieved. This strategy will provide a new idea for developing robust self-healing polymers.展开更多
文摘A novel dynamic optical add-drop multiplexer(OADM) scheme using tunable sampled fiber Bragg gratings(SFBG) by Vernier effect is firstly proposed. In this scheme, broad wavelength tuning range is achieved by only slightly adjusting the SFBG, the wavelength tuning of OADM will be faster than traditional dynamic OADM.
基金Supported by the National Natural Science Foundation of China (No.60496311) and partially supported by the B3G project (2003AA123310).
文摘We investigate an adaptive cooperative protocol in a Two-Hop-Relay (THR) wireless system that combines the following: (1) adaptive relaying based on repetition coding; (2) single or two transmit antennas and one receive antenna configurations for all nodes, each using high order constellation; (3) Bit-Interleaved Coded Modulation (BICM). We focus on a simple decoded relaying (i.e. no error correcting at a relay node) and simple signal quality thresholds for relaying. Then the impact of the two simple thresholds on the system performance is studied. Our results suggest that compared with the traditional scheme for direct transmission, the proposed scheme can increase average throughput in high spectral efficiency region with low implementa-tion-cost at the relay.
文摘The aim of this paper is to reveal the mechanism of compromise and change in coordination where players agree in general but disagree on coordination methods. When players agree on the need to collaborate but are in conflict regarding the specific method, one player must always compromise. This situation is known as the Battle of the Sexes in game theory. It has ever been believed that if an agreement is reached under such circumstances, the players do not have the incentive to withdraw from the agreement. However, this study shows that this belief is not always true if the players were able to revise the outcome of their negotiations later. The wide-ranging fields use game theories for their analysis frameworks to analyze the success or failure of coordination. However, comparing with the possibility of betrayal illustrated as a well-known Prisoner Dilemma, it has been rare to discuss conflict regarding the specific method of coordination, although such situations are often observed in today＇s interdependent real world. The repeated Battle of the Sexes games presented in this study would be a useful framework to analyze conflict regarding the specific method of coordination.
文摘The performances of nonlinear WDM systems with different duty cycle are compared by means of numerical simulation.The numerical results show that the optical pulse with duty cycle of 0.5 is superior to the conventional NRZ modulation scheme.The conclusion is different from that of some references.The reason is that inter symbol interference is not included in some references.In fact,inter symbol interference plays an important role in nonlinear WDM system.Although the larger the duty cycle is ,the stronger the effect of the cross-phase modulation and self-phase modulation on nonlinear WDM is,however,the larger the duty cycle is,the stronger the inter symbol interference is.
基金supported by China’s Recruitment Program of Global Experts,National Natural Science Foundation of China(Grant No.11321101)Hua Loo-Keng Key Laboratory of Mathematics,Chinese Academy of Sciences,National Center for Mathematics and Interdisciplinary Sciences and Chinese Academy of Sciences
文摘Laszlo and Olsson constructed Grothendieck＇s six operations for constructible complexes on Artin stacks in etale cohomology under an assumption of finite cohomological dimension, with base change established on the level of sheaves. We give a more direct construction of the six operations for complexes on Deligne- Mumford stacks without the finiteness assumption and establish base change theorems in derived categories. One key tool in our construction is the theory of gluing finitely many pseudofunctors developed by Zheng （2014）. As an application, we prove a Lefschetz-Verdier formula for Deligne-Mumford stacks. We include both torsion and l-adic coefficients.
基金financially supported by the National Natural Science Foundation of China(51773131,51811530149and 51721091)the International S&T Cooperation Project of Sichuan Province(2017HH0034)
文摘Self-healing materials have attracted considerable attention because of their improved safety, lifetime, energy efficiency and environmental impact. Supramolecular interactions have been extensively considered in the field of self-healing materials due to their excellent reversibility and sensitive responsiveness to environmental stimuli. However,development of a polymeric material with good mechanical performance as well as self-healing capacity is very challenging. In this study, we report a robust self-healing polyurethane(PU) elastomer polypropylene glycol-2-amino-5-(2-hydroxyethyl)-6-methylpyrimidin-4-ol(PPG-mUPy) by integrating ureidopyrimidone(UPy) motifs with a PPG segment with a well-defined architecture and microphase morphology.To balance the self-healing capacity and mechanical performance, a thermal-triggered switch of H-bonding is introduced. The quadruple H-bonded UPy dimeric moieties in the backbone induce phase separation to form a hard domain as well as enable further aggregation into microcrystals by virtue of the stacking interactions, which are stable in ambient temperature. This feature endows the PU with high mechanical strength. Meanwhile, a high healing efficiency can be realized, when the reversibility of the H-bond was unlocked from the stacking at higher temperature. An optimized sample PPG1000-mUPy50%with a good balance of mechanical performance(20.62 MPa of tensile strength) and healing efficiency(93% in tensile strength) was achieved. This strategy will provide a new idea for developing robust self-healing polymers.
