Presents the synthesis of Copolyimide containing triarylamine and NLO chromophore in backbone by azo coupling of 4 nitrobenzenediazonium tetrafloroborate to copoly(amic acid) in organic solvent and characterized by IR...Presents the synthesis of Copolyimide containing triarylamine and NLO chromophore in backbone by azo coupling of 4 nitrobenzenediazonium tetrafloroborate to copoly(amic acid) in organic solvent and characterized by IR and UV Vis spectra, which had high glass transition temperatrue and big second order nonlinear optical coefficient x (2) .展开更多
在无线通信定位中,无线信号中引入的非视距(Non-Line of Sight,NLOS)误差会严重降低系统的定位精度。针对上述问题,首先引入信息阈值和缩放因子,细分非视距误差的影响程度,对卡尔曼迭代过程中的增益进行更为精准的实时调整,利用改进后...在无线通信定位中,无线信号中引入的非视距(Non-Line of Sight,NLOS)误差会严重降低系统的定位精度。针对上述问题,首先引入信息阈值和缩放因子,细分非视距误差的影响程度,对卡尔曼迭代过程中的增益进行更为精准的实时调整,利用改进后的卡尔曼滤波算法更大程度上消除了NLOS误差和系统测量误差;其次引入基于测距残差的加权系数对线性位置线(Linear Line of Position,LLOP)和Taylor定位方法的计算结果进行综合处理,进一步提高定位精度和稳健性。实验结果表明,在NLOS环境下,所提算法优于经典的LLOP算法、Chan算法、LLOP-Taylor算法和基于卡尔曼滤波的LLOP算法。展开更多
针对复杂室内环境下超宽带(Ultra WideBand,UWB)信号传播的非视距(Non Line Of Sight,NLOS)误差问题,本文提出了一种基于无迹卡尔曼滤波(Unscented Kalman Filter,UKF)的环境自适应UWB/DR室内定位方法.该方法通过建立自适应UKF滤波模型,...针对复杂室内环境下超宽带(Ultra WideBand,UWB)信号传播的非视距(Non Line Of Sight,NLOS)误差问题,本文提出了一种基于无迹卡尔曼滤波(Unscented Kalman Filter,UKF)的环境自适应UWB/DR室内定位方法.该方法通过建立自适应UKF滤波模型,将UWB定位信息和航迹推算(Dead Reckoning,DR)定位信息进行融合.依据新息和高斯分布的3σ原则来对UWB定位结果进行非视距检测,再通过新息的实时估计协方差和理论协方差来构建环境适应系数,进而用此系数动态修正UWB定位的观测噪声,使得观测噪声自适应真实环境,降低NLOS误差对融合定位结果的影响.实验结果表明,该方法能有效减小UWB定位的NLOS误差,并且由于环境适应系数的创新引入,比UKF定位和粒子滤波定位(Particle Filtering,PF)有更高的定位精度和更强的抗NLOS误差性能.展开更多
The geometrical structures and stability of non-conjugated C5H10 and C3H8N2 singlet and triplet diradical molecules have been investigated at the UCCSD/6-311g^＊＊ level. The effects of molecular structure, radical po...The geometrical structures and stability of non-conjugated C5H10 and C3H8N2 singlet and triplet diradical molecules have been investigated at the UCCSD/6-311g^＊＊ level. The effects of molecular structure, radical position, amount of Hartree Hork （HF） exchange and spin multiplicity on the nonlinear optical （NLO） coefficients have been also investigated. The reliable UCCSD results show that the triplets of all diradical molecules are more stable compared to their singlet analogues. In addition, the αs and βtot values of C5H10 and C3H8N2 triplet diradical mo-lecules have been investigated by the UBHandHLYP, UB3LYP, UBLYP, UHF and UCCSD methods. The investigation shows that the variations in αs and βtot values are closely connected to the amount of HF exchange. The increasing amount of HF exchange results in monotonic decreases in αs and βtot values, while the αs and βtot values of singlet diradical molecules and the γs of C5H10 and C3H8N2 singlet and triplet diradical molecules have been studied by the UBHandHLYP method. The results illustrate that the NLO coefficients for our studied non-conjugated carbon and nitrogen diradical species can be tuned by molecular structure, radical position and spin multiplicity, which are very significant for designing NLO materials.展开更多
hydroxy-4-nitro azobenzene (NHA) and 4-amino-4-nitro azobenzene (DO3) were prepared respectively from p-nitrophenylamine as a precursor compound. Two kinds of doped organic/inorganic hybrid nonlinear optical (NLO) mat...hydroxy-4-nitro azobenzene (NHA) and 4-amino-4-nitro azobenzene (DO3) were prepared respectively from p-nitrophenylamine as a precursor compound. Two kinds of doped organic/inorganic hybrid nonlinear optical (NLO) materials containing NHA and DO3 were synthesized by Sol-Gel process. The preparation and properties of two NLO materials were studied and characterized by FTIR, 1H-NMR, UV-VIS, SEM, DSC and SHG measurements. The results show that the maximum doping amounts of NHA and DO3 in two doped hybrid NLO materials are 7.2(wt)% and 11.3(wt)% respectively, and the corresponding second-order NLO coefficients (d33 values) are 2.91×10 8esu and 6.14×10 8esu. Two doped NLO materials have relatively good RT stability, after 90 days at RT the d33 values can maintain about 85% of their initial values, but after 10h at 100℃ can only maintain about 50% of their initial values. In this report, the reasons for high-temperature instability of doped materials were discussed, and the possible improvements were also suggested.展开更多
文摘Presents the synthesis of Copolyimide containing triarylamine and NLO chromophore in backbone by azo coupling of 4 nitrobenzenediazonium tetrafloroborate to copoly(amic acid) in organic solvent and characterized by IR and UV Vis spectra, which had high glass transition temperatrue and big second order nonlinear optical coefficient x (2) .
文摘在无线通信定位中,无线信号中引入的非视距(Non-Line of Sight,NLOS)误差会严重降低系统的定位精度。针对上述问题,首先引入信息阈值和缩放因子,细分非视距误差的影响程度,对卡尔曼迭代过程中的增益进行更为精准的实时调整,利用改进后的卡尔曼滤波算法更大程度上消除了NLOS误差和系统测量误差;其次引入基于测距残差的加权系数对线性位置线(Linear Line of Position,LLOP)和Taylor定位方法的计算结果进行综合处理,进一步提高定位精度和稳健性。实验结果表明,在NLOS环境下,所提算法优于经典的LLOP算法、Chan算法、LLOP-Taylor算法和基于卡尔曼滤波的LLOP算法。
文摘针对复杂室内环境下超宽带(Ultra WideBand,UWB)信号传播的非视距(Non Line Of Sight,NLOS)误差问题,本文提出了一种基于无迹卡尔曼滤波(Unscented Kalman Filter,UKF)的环境自适应UWB/DR室内定位方法.该方法通过建立自适应UKF滤波模型,将UWB定位信息和航迹推算(Dead Reckoning,DR)定位信息进行融合.依据新息和高斯分布的3σ原则来对UWB定位结果进行非视距检测,再通过新息的实时估计协方差和理论协方差来构建环境适应系数,进而用此系数动态修正UWB定位的观测噪声,使得观测噪声自适应真实环境,降低NLOS误差对融合定位结果的影响.实验结果表明,该方法能有效减小UWB定位的NLOS误差,并且由于环境适应系数的创新引入,比UKF定位和粒子滤波定位(Particle Filtering,PF)有更高的定位精度和更强的抗NLOS误差性能.
基金Supported by the National Natural Science Foundation of China (20873017)the Natural Science Foundation of Jilin Province (20101154)
文摘The geometrical structures and stability of non-conjugated C5H10 and C3H8N2 singlet and triplet diradical molecules have been investigated at the UCCSD/6-311g^＊＊ level. The effects of molecular structure, radical position, amount of Hartree Hork （HF） exchange and spin multiplicity on the nonlinear optical （NLO） coefficients have been also investigated. The reliable UCCSD results show that the triplets of all diradical molecules are more stable compared to their singlet analogues. In addition, the αs and βtot values of C5H10 and C3H8N2 triplet diradical mo-lecules have been investigated by the UBHandHLYP, UB3LYP, UBLYP, UHF and UCCSD methods. The investigation shows that the variations in αs and βtot values are closely connected to the amount of HF exchange. The increasing amount of HF exchange results in monotonic decreases in αs and βtot values, while the αs and βtot values of singlet diradical molecules and the γs of C5H10 and C3H8N2 singlet and triplet diradical molecules have been studied by the UBHandHLYP method. The results illustrate that the NLO coefficients for our studied non-conjugated carbon and nitrogen diradical species can be tuned by molecular structure, radical position and spin multiplicity, which are very significant for designing NLO materials.
基金Plan Project of Science and Technology of Guangzhou City (2002J1-C0061) The First Author: XI Hongxia(1968-)
文摘hydroxy-4-nitro azobenzene (NHA) and 4-amino-4-nitro azobenzene (DO3) were prepared respectively from p-nitrophenylamine as a precursor compound. Two kinds of doped organic/inorganic hybrid nonlinear optical (NLO) materials containing NHA and DO3 were synthesized by Sol-Gel process. The preparation and properties of two NLO materials were studied and characterized by FTIR, 1H-NMR, UV-VIS, SEM, DSC and SHG measurements. The results show that the maximum doping amounts of NHA and DO3 in two doped hybrid NLO materials are 7.2(wt)% and 11.3(wt)% respectively, and the corresponding second-order NLO coefficients (d33 values) are 2.91×10 8esu and 6.14×10 8esu. Two doped NLO materials have relatively good RT stability, after 90 days at RT the d33 values can maintain about 85% of their initial values, but after 10h at 100℃ can only maintain about 50% of their initial values. In this report, the reasons for high-temperature instability of doped materials were discussed, and the possible improvements were also suggested.
