Organic light-emitting diodes （OLEDs） have been extensively studied since the first efficient device based on small molecular luminescent materials was reported by Tang. Organic electroluminescent material, one of t...Organic light-emitting diodes （OLEDs） have been extensively studied since the first efficient device based on small molecular luminescent materials was reported by Tang. Organic electroluminescent material, one of the centerpieces of OLEDs, has been the focus of studies by many material scientists. To obtain high luminosity and to keep material costs low, a few remarkable design concepts have been developed. Aggregation-induced emission （AIE） materials were invented to overcome the common fluorescence-quenching problem, and cross-dipole stacking of fluorescent molecules was shown to be an effective method to get high solid-state luminescence. To exceed the limit of internal quantum efficiency of conventional fluorescent materials, phosphorescent materials were successfully applied in highly efficient electroluminescent devices. Most recently, delayed flu- orescent materials via reverse-intersystem crossing （RISC） from triplet to singlet and the ＂hot exciton＂ materials based on hy- bridized local and charge-transfer （HLCT） states were developed to he a new generation of low-cost luminescent materials as efficient as phosphorescent materials. In terms of the device-fabrication process, solution-processible small molecular lumi- nescent materials possess the advantages of high purity （vs. polymers） and low procession cost （vs. vacuum deposition）, which are garnering them increasing attention. Herein, we review the progress of the development of small-molecule luminescent materials with different design concepts and features, and also briefly examine future development tendencies of luminescent materials.展开更多
Small-state stream ciphers(SSCs),which violate the principle that the state size should exceed the key size by a factor of two,still demonstrate robust security properties while maintaining a lightweight design.These ...Small-state stream ciphers(SSCs),which violate the principle that the state size should exceed the key size by a factor of two,still demonstrate robust security properties while maintaining a lightweight design.These ciphers can be clas-sifed into several constructions and their basic security requirement is to resist generic attacks,ie.,the time-mem-ory-data tradeoff(TMDTO)attack.In this paper,we investigate the security of small-state constructions in the multi-user setting.Based on it,the TMDTO distinguishing attack and the TMDTO key recovery attack are developed for such a setting.It is shown that SSCs which continuously use the key can not resist the TMDTO distinguishing attack.Moreover,SSCs based on the continuous-IV-key-use construction cannot withstand the TMDTO key recovery attack when the key length is shorter than the IV length,no matter whether the keystream length is limited or not.Finally,We apply these two generic attacks to TinyJAMBU and DRACO in the multi-user setting.The TMDTO distinguish-ing attack on TinyJAMBU with a 128-bit key can be mounted with time,memory,and data complexities of 264,248,and 232,respectively.This attack is comparable with a recent work on ToSC 2022,where partial key bits of TinyJAMBU are recovered with more than 250 users(or keys).As DRACO's IV length is smaller than its key length,itis vulnerable to the TMDTO key recovery attack.The resulting attack has a time and memory complexity of both 2112,which means DRACO does not provide 128-bit security in the multi-user setting.展开更多
This paper studies the stability problem for networked control systems.A general result,called network gain theorem,is introduced to determine the input-to-state stability(ISS)for interconnected nonlinear systems.We s...This paper studies the stability problem for networked control systems.A general result,called network gain theorem,is introduced to determine the input-to-state stability(ISS)for interconnected nonlinear systems.We show how this result generalises the previously known small gain theorem and cyclic small gain theorem for ISS.For the case of linear networked systems,a complete characterisation of the stability condition is provided,together with two distributed algorithms for computing the network gain:the classical Jacobi iterations and a message-passing algorithm.For the case of nonlinear networked systems,characterisation of the ISS condition can be done using M-functions,and Jacobi iterations can be used to compute the network gain.展开更多
The problem of a small magnet levitating above a very thin superconducting disc in the Meissner state is analysed. The dipole-dipole interaction model is employed to derive analytical expressions for the interaction e...The problem of a small magnet levitating above a very thin superconducting disc in the Meissner state is analysed. The dipole-dipole interaction model is employed to derive analytical expressions for the interaction energy, levitation force, magnetic stiffness and frequency of small vibrations about the equilibrium position in two different configurations, i.e. with the magnetic moment parallel and perpendicular to the superconductor. The results show that the frequency of small vibrations decreases with the increasing levitation height for a particular radius of the superconducting disc, which is in good agreement with the experimental results. However, the frequency increases monotonically up to saturation by increasing the radius of the disc for a particular height of the magnet. In addition, the frequency of vibrations is higher when the system is in the vertical configuration than that when the system is in the horizontal configuration.展开更多
By means of the reduced-density linear entropy, we investigate the properties of dynamical entanglement of vibrations in integrable dimer and realistic small molecules which are initially in the two-mode squeezed vacu...By means of the reduced-density linear entropy, we investigate the properties of dynamical entanglement of vibrations in integrable dimer and realistic small molecules which are initially in the two-mode squeezed vacuum state. It is found that the entropy of the integrable dimer is periodic for weak coupling strength cl and small squeezing parameter r, and there exists a beat phenomenon for strong el and large r. Moreover, the entropy of the small molecules is quasi-periodic for small r, ＆nd the begt phenomenon occurs in the entropy evolution of the two molecules C2D2 and S02 for large r. Our results might be used for molecular quantum computing based on vibrational states.展开更多
The problem of comprehensive evaluation of liying basis for small businesses is discussed, based on fuzziness of index, a corresponding fuzzy state comprehensive evaluation method is presented; the good results that i...The problem of comprehensive evaluation of liying basis for small businesses is discussed, based on fuzziness of index, a corresponding fuzzy state comprehensive evaluation method is presented; the good results that is,the evaluation of living basis for small business are illustrated by a simulated example.展开更多
Knowing the temperature distribution in silo is a convenient and efficient way to control the process of grain storage.A three-dimensional(3-D)numerical model was used to study the temperature variation in small grain...Knowing the temperature distribution in silo is a convenient and efficient way to control the process of grain storage.A three-dimensional(3-D)numerical model was used to study the temperature variation in small grain steel silo under quasi-steady state.In this study,experiments were conducted and porous media model was adopted.Results of numerical simulation and experiment were compared and the results indicated that grain temperature was influenced by temperature of the wall,grain stacking height,and the distance between grain and wall.The higher the wall temperature,the more the temperature increases.If the wall temperature is low,the effect of wall temperature on temperature distribution is significant.The temperature at the top part of grain varied obviously with the changes of temperature in air layer.Overall,numerical simulation results coincided with experimental results and the model established in this study is valuable for predicting grain temperature in steel silo.展开更多
基金supported by the National Natural Science Foundation of China(21334002,51303057,51373054,91233113)the National Basic Research Program of China(2013CB834705,2014CB643504,2015CB655003)+1 种基金the Fundamental Research Funds for the Central Universities(2013ZZ0001)the Introduced Innovative R&D Team of Guangdong(201101C0105067115)
文摘Organic light-emitting diodes （OLEDs） have been extensively studied since the first efficient device based on small molecular luminescent materials was reported by Tang. Organic electroluminescent material, one of the centerpieces of OLEDs, has been the focus of studies by many material scientists. To obtain high luminosity and to keep material costs low, a few remarkable design concepts have been developed. Aggregation-induced emission （AIE） materials were invented to overcome the common fluorescence-quenching problem, and cross-dipole stacking of fluorescent molecules was shown to be an effective method to get high solid-state luminescence. To exceed the limit of internal quantum efficiency of conventional fluorescent materials, phosphorescent materials were successfully applied in highly efficient electroluminescent devices. Most recently, delayed flu- orescent materials via reverse-intersystem crossing （RISC） from triplet to singlet and the ＂hot exciton＂ materials based on hy- bridized local and charge-transfer （HLCT） states were developed to he a new generation of low-cost luminescent materials as efficient as phosphorescent materials. In terms of the device-fabrication process, solution-processible small molecular lumi- nescent materials possess the advantages of high purity （vs. polymers） and low procession cost （vs. vacuum deposition）, which are garnering them increasing attention. Herein, we review the progress of the development of small-molecule luminescent materials with different design concepts and features, and also briefly examine future development tendencies of luminescent materials.
基金This work was supported by the National Natural Science Foundation of China[grant number 62022036,62132008,62372213].
文摘Small-state stream ciphers(SSCs),which violate the principle that the state size should exceed the key size by a factor of two,still demonstrate robust security properties while maintaining a lightweight design.These ciphers can be clas-sifed into several constructions and their basic security requirement is to resist generic attacks,ie.,the time-mem-ory-data tradeoff(TMDTO)attack.In this paper,we investigate the security of small-state constructions in the multi-user setting.Based on it,the TMDTO distinguishing attack and the TMDTO key recovery attack are developed for such a setting.It is shown that SSCs which continuously use the key can not resist the TMDTO distinguishing attack.Moreover,SSCs based on the continuous-IV-key-use construction cannot withstand the TMDTO key recovery attack when the key length is shorter than the IV length,no matter whether the keystream length is limited or not.Finally,We apply these two generic attacks to TinyJAMBU and DRACO in the multi-user setting.The TMDTO distinguish-ing attack on TinyJAMBU with a 128-bit key can be mounted with time,memory,and data complexities of 264,248,and 232,respectively.This attack is comparable with a recent work on ToSC 2022,where partial key bits of TinyJAMBU are recovered with more than 250 users(or keys).As DRACO's IV length is smaller than its key length,itis vulnerable to the TMDTO key recovery attack.The resulting attack has a time and memory complexity of both 2112,which means DRACO does not provide 128-bit security in the multi-user setting.
基金supported in part by the National Natural Science Foundation of China(Nos.U21A20476,U1911401,U22A20221,62273100,62073090).
文摘This paper studies the stability problem for networked control systems.A general result,called network gain theorem,is introduced to determine the input-to-state stability(ISS)for interconnected nonlinear systems.We show how this result generalises the previously known small gain theorem and cyclic small gain theorem for ISS.For the case of linear networked systems,a complete characterisation of the stability condition is provided,together with two distributed algorithms for computing the network gain:the classical Jacobi iterations and a message-passing algorithm.For the case of nonlinear networked systems,characterisation of the ISS condition can be done using M-functions,and Jacobi iterations can be used to compute the network gain.
文摘The problem of a small magnet levitating above a very thin superconducting disc in the Meissner state is analysed. The dipole-dipole interaction model is employed to derive analytical expressions for the interaction energy, levitation force, magnetic stiffness and frequency of small vibrations about the equilibrium position in two different configurations, i.e. with the magnetic moment parallel and perpendicular to the superconductor. The results show that the frequency of small vibrations decreases with the increasing levitation height for a particular radius of the superconducting disc, which is in good agreement with the experimental results. However, the frequency increases monotonically up to saturation by increasing the radius of the disc for a particular height of the magnet. In addition, the frequency of vibrations is higher when the system is in the vertical configuration than that when the system is in the horizontal configuration.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11174081,11034002,11104075,60708003,and 11134003the National Basic Research Program of China under Grant Nos.2011CB921602 and 2012CB821302
文摘By means of the reduced-density linear entropy, we investigate the properties of dynamical entanglement of vibrations in integrable dimer and realistic small molecules which are initially in the two-mode squeezed vacuum state. It is found that the entropy of the integrable dimer is periodic for weak coupling strength cl and small squeezing parameter r, and there exists a beat phenomenon for strong el and large r. Moreover, the entropy of the small molecules is quasi-periodic for small r, ＆nd the begt phenomenon occurs in the entropy evolution of the two molecules C2D2 and S02 for large r. Our results might be used for molecular quantum computing based on vibrational states.
文摘The problem of comprehensive evaluation of liying basis for small businesses is discussed, based on fuzziness of index, a corresponding fuzzy state comprehensive evaluation method is presented; the good results that is,the evaluation of living basis for small business are illustrated by a simulated example.
基金National Natural Science Foundation of China(31271972)Science and Technology Innovation Team in Universities of Henan Province(16IRTSTHN009).
文摘Knowing the temperature distribution in silo is a convenient and efficient way to control the process of grain storage.A three-dimensional(3-D)numerical model was used to study the temperature variation in small grain steel silo under quasi-steady state.In this study,experiments were conducted and porous media model was adopted.Results of numerical simulation and experiment were compared and the results indicated that grain temperature was influenced by temperature of the wall,grain stacking height,and the distance between grain and wall.The higher the wall temperature,the more the temperature increases.If the wall temperature is low,the effect of wall temperature on temperature distribution is significant.The temperature at the top part of grain varied obviously with the changes of temperature in air layer.Overall,numerical simulation results coincided with experimental results and the model established in this study is valuable for predicting grain temperature in steel silo.
