With the rapid development of internet technology,security protection of information has become more and more prominent,especially information encryption.Considering the great advantages of chaotic encryption,we propo...With the rapid development of internet technology,security protection of information has become more and more prominent,especially information encryption.Considering the great advantages of chaotic encryption,we propose a 2D-lag complex logistic map with complex parameters(2D-LCLMCP)and corresponding encryption schemes.Firstly,we present the model of the 2D-LCLMCP and analyze its chaotic properties and system stability through fixed points,Lyapunov exponent,bifurcation diagram,phase diagram,etc.Secondly,a block cipher algorithm based on the 2D-LCLMCP is proposed,the plaintext data is preprocessed using a pseudorandom sequence generated by the 2D-LCLMCP.Based on the generalized Feistel cipher structure,a round function F is constructed using dynamic S-box and DNA encoding rules as the core of the block cipher algorithm.The generalized Feistel cipher structure consists of two F functions,four XOR operations,and one permutation operation per round.The symmetric dynamic round keys that change with the plaintext are generated by the 2D-LCLMCP.Finally,experimental simulation and performance analysis tests are conducted.The results show that the block cipher algorithm has low complexit,good diffusion and a large key space.When the block length is 64 bits,only six rounds of encryption are required to provide sufficient security and robustness against cryptographic attacks.展开更多
A robust adaptive controller for a nonholonomic mobile robot with unknown kinematic and dynamic parameters is proposed. A kinematic controller whose output is the input of the relevant dynamic controller is provided b...A robust adaptive controller for a nonholonomic mobile robot with unknown kinematic and dynamic parameters is proposed. A kinematic controller whose output is the input of the relevant dynamic controller is provided by using the concept of backstepping. An adaptive algorithm is developed in the kinematic controller to approximate the unknown kinematic parameters, and a simple single-layer neural network is used to express the highly nonlinear robot dynamics in terms of the known and unknown parameters. In order to attenuate the effects of the uncertainties and disturbances on tracking performance, a sliding mode control term is added to the dynamic controller. In the deterministic design of feedback controllers for the uncertain dynamic systems, upper bounds on the norm of the uncertainties are an important clue to guarantee the stability of the closed-loop system. However, sometimes these upper bounds may not be easily obtained because of the complexity of the structure of the uncertainties. Thereby, simple adaptation laws are proposed to approximate upper bounds on the norm of the uncertainties to address this problem. The stability of the proposed control system is shown through the Lyapunov method. Lastly, a design example for a mobile robot with two actuated wheels is provided and the feasibility of the controller is demonstrated by numerical simulations.展开更多
Photodetectors with long detection distances and fast response are important media in constructing a non-contact human-machine interface for the Masterly Internet of Things(MIT).All-inorganic perovskites have excellen...Photodetectors with long detection distances and fast response are important media in constructing a non-contact human-machine interface for the Masterly Internet of Things(MIT).All-inorganic perovskites have excellent optoelectronic performance with high moisture and oxygen resistance,making them one of the promising candidates for high-performance photodetectors,but a simple,low-cost and reliable fabrication technology is urgently needed.Here,a dual-function laser etching method is developed to complete both the lyophilic split-ring structure and electrode patterning.This novel split-ring structure can capture the perovskite precursor droplet efficiently and achieve the uniform and compact deposition of CsPbBr3 films.Furthermore,our devices based on laterally conducting split-ring structured photodetectors possess outstanding performance,including the maximum responsivity of 1.44×105 mA W^(−1),a response time of 150μs in 1.5 kHz and one-unit area<4×10-2 mm2.Based on these split-ring photodetector arrays,we realized three-dimensional gesture detection with up to 100 mm distance detection and up to 600 mm s^(−1) speed detection,for low-cost,integrative,and non-contact human-machine interfaces.Finally,we applied this MIT to wearable and flexible digital gesture recognition watch panel,safe and comfortable central controller integrated on the car screen,and remote control of the robot,demonstrating the broad potential applications.展开更多
The existing current break protection cannot achieve full-line current protection and may lose its protection capability. Therefore, a self-adjusted full-line current protection strategy based on a double-layer criter...The existing current break protection cannot achieve full-line current protection and may lose its protection capability. Therefore, a self-adjusted full-line current protection strategy based on a double-layer criterion is proposed. The first layer of the criterion adopts the adaptive adjustment threshold as the setting value to realize full-line fault monitoring, which is not affected by the system operation mode and fault type. The second layer is used to locate the fault section of the line and improve the selectivity of the protection strategy. Considering the difficulty in accurately identifying high-resistance ground faults using current protection, an identification method based on compound power is proposed by analyzing the zero-sequence network of the system. Simulation results show that the proposed protection strategy can realize full-length line protection and the effective identification of high-resistance ground faults and is not affected by the system load variation and fault type.展开更多
SnO_2 quantum dots(QDs) ended with chlorine ions are introduced at the interface of spin-coated TiO_2 electron selective layer(ESL)/perovskite to fill the pinholes in the layer and passivate the trapping defects. As a...SnO_2 quantum dots(QDs) ended with chlorine ions are introduced at the interface of spin-coated TiO_2 electron selective layer(ESL)/perovskite to fill the pinholes in the layer and passivate the trapping defects. As a result of the increased interface electron collection and reduced bulk recombination, the planar perovskite solar cell with the QDs modified ESL gives the large power conversion efficiency enhancement from 14.9% to 17.3% and greatly improved stability under the continuous light irradiation.展开更多
Surface enhanced Raman scattering(SERS)is a rapid and nondestructive technique that is capable of detecting and identifying chemical or biological compounds.Sensitive SERS quantification is vital for practical applica...Surface enhanced Raman scattering(SERS)is a rapid and nondestructive technique that is capable of detecting and identifying chemical or biological compounds.Sensitive SERS quantification is vital for practical applications,particularly for portable detection of biomolecules such as amino acids and nucleotides.However,few approaches can achieve sensitive and quantitative Raman detection of these most fundamental components in biology.Herein,a noblemetal-free single-atom site on a chip strategy was applied to modify single tungsten atom oxide on a lead halide perovskite,which provides sensitive SERS quantification for various analytes,including rhodamine,tyrosine and cytosine.The single-atom site on a chip can enable quantitative linear SERS responses of rhodamine(10^(−6)-1 mmol L^(−1)),tyrosine(0.06-1 mmol L^(−1))and cytosine(0.2-45 mmol L^(−1)),respectively,which all achieve record-high enhancement factors among plasmonic-free semiconductors.The experimental test and theoretical simulation both reveal that the enhanced mechanism can be ascribed to the controllable single-atom site,which can not only trap photoinduced electrons from the perovskite substrate but also enhance the highly efficient and quantitative charge transfer to analytes.Furthermore,the label-free strategy of single-atom sites on a chip can be applied in a portable Raman platform to obtain a sensitivity similar to that on a benchtop instrument,which can be readily extended to various biomolecules for low-cost,widely demanded and more precise point-of-care testing or in-vitro detection.展开更多
Droplet-based microfluidic technology can be utilized as a microreactor to prepare novel functional monodisperse microcapsules.In this study,a droplet-based microfluidic chip with surface modification,which allowed th...Droplet-based microfluidic technology can be utilized as a microreactor to prepare novel functional monodisperse microcapsules.In this study,a droplet-based microfluidic chip with surface modification,which allowed the one-step preparation of double emulsion microcapsules.An O/W/O double emulsion using polyethylene(glycol)diacrylate(PEGDA)solution as the intermediate water phase was prepared by regulating the hydrophilicity and hydrophobicity of the chip surface,with PEGDA microcapsules prepared using UV polymerization.And then anti-tumor drug paclitaxel and neurotoxin 6-OHDA were encapsulated in microcapsules for drug and toxicology evaluation,respectively.Compared to controls,drug-loaded mi-crocapsules caused a significant increase in the death rate of PC12 cells.This indicates that the obtained drug-loaded microcapsules could be used in drug evaluation and potentially in drug screening and deliv-ery.展开更多
The influence of material micro-defects on the main crack growth under pure shear loading is studied theoretically.The mechanism behind the initiation of micro-cracks and crack propagation induced by dislocation accum...The influence of material micro-defects on the main crack growth under pure shear loading is studied theoretically.The mechanism behind the initiation of micro-cracks and crack propagation induced by dislocation accumulation near the grain boundary(GB)ismainly considered,and the influence of dislocation accumulation on the main crack propagation is analyzed.The research results reveal that the initiation of micro-cracks near the GB is prior to the propagation of the main crack.In a hydrogen environment,hydrogen can cause serious embrittlement of the crack tip and promote crack growth.The energy release rate in the main crack growth direction in the dislocation emission direction is the highest.Therefore,the main crack will eventually merge with the micro-cracks at the GB along the direction of the slip band,resulting in fracture of the crystal material.The research presented in this paper provides some new information for the first stage of crack propagation and contributes to the analysis of the mechanism of crystal metal fracture.展开更多
基金Project supported by the Shandong Province Natural Science Foundation(Grant Nos.ZR2023MF089,R2023QF036,and ZR2021MF073)the Industry-University-Research Collaborative Innovation Fund Project of Qilu University of Technology(Shandong Academy of Sciences)(Grant Nos.2021CXY-13 and 2021CXY-14)+2 种基金the Major Scientific and Technological Innovation Projects of Shandong Province(Grant No.2020CXGC010901)the Talent Research Project of Qilu University of Technology(Shandong Academy of Sciences)(Grant No.2023RCKY054)the Basic Research Projects of Science,Education and Industry Integration Pilot Project of Qilu University of Technology(Shandong Academy of Sciences)(Grant No.2023PX081)。
文摘With the rapid development of internet technology,security protection of information has become more and more prominent,especially information encryption.Considering the great advantages of chaotic encryption,we propose a 2D-lag complex logistic map with complex parameters(2D-LCLMCP)and corresponding encryption schemes.Firstly,we present the model of the 2D-LCLMCP and analyze its chaotic properties and system stability through fixed points,Lyapunov exponent,bifurcation diagram,phase diagram,etc.Secondly,a block cipher algorithm based on the 2D-LCLMCP is proposed,the plaintext data is preprocessed using a pseudorandom sequence generated by the 2D-LCLMCP.Based on the generalized Feistel cipher structure,a round function F is constructed using dynamic S-box and DNA encoding rules as the core of the block cipher algorithm.The generalized Feistel cipher structure consists of two F functions,four XOR operations,and one permutation operation per round.The symmetric dynamic round keys that change with the plaintext are generated by the 2D-LCLMCP.Finally,experimental simulation and performance analysis tests are conducted.The results show that the block cipher algorithm has low complexit,good diffusion and a large key space.When the block length is 64 bits,only six rounds of encryption are required to provide sufficient security and robustness against cryptographic attacks.
基金partly supported by the National Natural Science Foundation of China (No.50625516)the 863 program of China(No.2006AA09Z203,2006AA04A110)
文摘A robust adaptive controller for a nonholonomic mobile robot with unknown kinematic and dynamic parameters is proposed. A kinematic controller whose output is the input of the relevant dynamic controller is provided by using the concept of backstepping. An adaptive algorithm is developed in the kinematic controller to approximate the unknown kinematic parameters, and a simple single-layer neural network is used to express the highly nonlinear robot dynamics in terms of the known and unknown parameters. In order to attenuate the effects of the uncertainties and disturbances on tracking performance, a sliding mode control term is added to the dynamic controller. In the deterministic design of feedback controllers for the uncertain dynamic systems, upper bounds on the norm of the uncertainties are an important clue to guarantee the stability of the closed-loop system. However, sometimes these upper bounds may not be easily obtained because of the complexity of the structure of the uncertainties. Thereby, simple adaptation laws are proposed to approximate upper bounds on the norm of the uncertainties to address this problem. The stability of the proposed control system is shown through the Lyapunov method. Lastly, a design example for a mobile robot with two actuated wheels is provided and the feasibility of the controller is demonstrated by numerical simulations.
基金support by the Key Research Project of Zhejiang Laboratory(N.O.2021PE0AC02)the National Natural Science Foundation of China(N.O.11674210)the Project of Hetao Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone(HZQB-KCZYB-2020083).
文摘Photodetectors with long detection distances and fast response are important media in constructing a non-contact human-machine interface for the Masterly Internet of Things(MIT).All-inorganic perovskites have excellent optoelectronic performance with high moisture and oxygen resistance,making them one of the promising candidates for high-performance photodetectors,but a simple,low-cost and reliable fabrication technology is urgently needed.Here,a dual-function laser etching method is developed to complete both the lyophilic split-ring structure and electrode patterning.This novel split-ring structure can capture the perovskite precursor droplet efficiently and achieve the uniform and compact deposition of CsPbBr3 films.Furthermore,our devices based on laterally conducting split-ring structured photodetectors possess outstanding performance,including the maximum responsivity of 1.44×105 mA W^(−1),a response time of 150μs in 1.5 kHz and one-unit area<4×10-2 mm2.Based on these split-ring photodetector arrays,we realized three-dimensional gesture detection with up to 100 mm distance detection and up to 600 mm s^(−1) speed detection,for low-cost,integrative,and non-contact human-machine interfaces.Finally,we applied this MIT to wearable and flexible digital gesture recognition watch panel,safe and comfortable central controller integrated on the car screen,and remote control of the robot,demonstrating the broad potential applications.
基金financial support the Key Research Project of Zhejiang Laboratory(2021PE0AC02)the National Natural Science Foundation of China(11704239,61922053,and 11674210)。
基金Supported by the National Natural Science Foundation of China(U22B20106)the State Grid Power Company of Hunan Province Science and Technology Project(5216A5220022).
文摘The existing current break protection cannot achieve full-line current protection and may lose its protection capability. Therefore, a self-adjusted full-line current protection strategy based on a double-layer criterion is proposed. The first layer of the criterion adopts the adaptive adjustment threshold as the setting value to realize full-line fault monitoring, which is not affected by the system operation mode and fault type. The second layer is used to locate the fault section of the line and improve the selectivity of the protection strategy. Considering the difficulty in accurately identifying high-resistance ground faults using current protection, an identification method based on compound power is proposed by analyzing the zero-sequence network of the system. Simulation results show that the proposed protection strategy can realize full-length line protection and the effective identification of high-resistance ground faults and is not affected by the system load variation and fault type.
基金financially supported by the National Natural Science Foundation of China (51825204)the Key Research Program of Frontier Sciences CAS (QYZDB-SSW-JSC039)
文摘SnO_2 quantum dots(QDs) ended with chlorine ions are introduced at the interface of spin-coated TiO_2 electron selective layer(ESL)/perovskite to fill the pinholes in the layer and passivate the trapping defects. As a result of the increased interface electron collection and reduced bulk recombination, the planar perovskite solar cell with the QDs modified ESL gives the large power conversion efficiency enhancement from 14.9% to 17.3% and greatly improved stability under the continuous light irradiation.
基金supported by the Natural Science Foundation of Beijing Municipality(Z180014)。
文摘Surface enhanced Raman scattering(SERS)is a rapid and nondestructive technique that is capable of detecting and identifying chemical or biological compounds.Sensitive SERS quantification is vital for practical applications,particularly for portable detection of biomolecules such as amino acids and nucleotides.However,few approaches can achieve sensitive and quantitative Raman detection of these most fundamental components in biology.Herein,a noblemetal-free single-atom site on a chip strategy was applied to modify single tungsten atom oxide on a lead halide perovskite,which provides sensitive SERS quantification for various analytes,including rhodamine,tyrosine and cytosine.The single-atom site on a chip can enable quantitative linear SERS responses of rhodamine(10^(−6)-1 mmol L^(−1)),tyrosine(0.06-1 mmol L^(−1))and cytosine(0.2-45 mmol L^(−1)),respectively,which all achieve record-high enhancement factors among plasmonic-free semiconductors.The experimental test and theoretical simulation both reveal that the enhanced mechanism can be ascribed to the controllable single-atom site,which can not only trap photoinduced electrons from the perovskite substrate but also enhance the highly efficient and quantitative charge transfer to analytes.Furthermore,the label-free strategy of single-atom sites on a chip can be applied in a portable Raman platform to obtain a sensitivity similar to that on a benchtop instrument,which can be readily extended to various biomolecules for low-cost,widely demanded and more precise point-of-care testing or in-vitro detection.
基金supported by the National Natural Science Foun-dation of China(Nos.31800848 and 21775101).
文摘Droplet-based microfluidic technology can be utilized as a microreactor to prepare novel functional monodisperse microcapsules.In this study,a droplet-based microfluidic chip with surface modification,which allowed the one-step preparation of double emulsion microcapsules.An O/W/O double emulsion using polyethylene(glycol)diacrylate(PEGDA)solution as the intermediate water phase was prepared by regulating the hydrophilicity and hydrophobicity of the chip surface,with PEGDA microcapsules prepared using UV polymerization.And then anti-tumor drug paclitaxel and neurotoxin 6-OHDA were encapsulated in microcapsules for drug and toxicology evaluation,respectively.Compared to controls,drug-loaded mi-crocapsules caused a significant increase in the death rate of PC12 cells.This indicates that the obtained drug-loaded microcapsules could be used in drug evaluation and potentially in drug screening and deliv-ery.
基金supported by the National Natural Science Foundation of China(Grant No.11472230).
文摘The influence of material micro-defects on the main crack growth under pure shear loading is studied theoretically.The mechanism behind the initiation of micro-cracks and crack propagation induced by dislocation accumulation near the grain boundary(GB)ismainly considered,and the influence of dislocation accumulation on the main crack propagation is analyzed.The research results reveal that the initiation of micro-cracks near the GB is prior to the propagation of the main crack.In a hydrogen environment,hydrogen can cause serious embrittlement of the crack tip and promote crack growth.The energy release rate in the main crack growth direction in the dislocation emission direction is the highest.Therefore,the main crack will eventually merge with the micro-cracks at the GB along the direction of the slip band,resulting in fracture of the crystal material.The research presented in this paper provides some new information for the first stage of crack propagation and contributes to the analysis of the mechanism of crystal metal fracture.
