Energetic compounds bearing the trinitromethyl group are garnering broad attraction as potential candidates for a new generation of high energy dense oxidizers.In this work,an effective dual modulation strategy involv...Energetic compounds bearing the trinitromethyl group are garnering broad attraction as potential candidates for a new generation of high energy dense oxidizers.In this work,an effective dual modulation strategy involving both molecular isomerization and crystal morphology control was employed to design and optimize trinitromethyl-oxadiazole with improved comprehensive performance.Utilizing this dual strategy,3,5-bis(trinitromethyl)-1,2,4-oxadiazole(3)was synthesized,resulting in the formation of two distinct crystal morphologies(needle and sheet)corresponding to two crystal forms(3-a and3-b).Encouragingly,while maintaining ultra-high oxygen balance(21.73%),3 achieves impressive densities(1.97-1.98 g/cm^(3)).To our knowledge,the density of 1.98 g/cm^(3)for 3-a sets a new record among that of nitrogen-rich monocyclic compounds.Notably,practical crystal morphology prediction was creatively introduced to guide the experimental crystallization conditions of 3,increasing the impact sensitivity and friction sensitivity from 1 J to 80 N(3-a)to 10 J and 240 N(3-b),respectively.Additionally,the crystal structural analyses and theoretical calculations were conducted to elucidate the reasons of differences between 3-a and 3-b in density and stability.This work provides an efficient strategy to enhance performance of trinitromethyl derivatives,broadening the path and expanding the toolbox for energetic materials.展开更多
A millimeter-wave (mmW) broadband dual circularly polarized (dual-CP) antenna with high port isolation is proposed in this paper. The dual-CP performance is realized based on the symmetrical septum circular polarizer ...A millimeter-wave (mmW) broadband dual circularly polarized (dual-CP) antenna with high port isolation is proposed in this paper. The dual-CP performance is realized based on the symmetrical septum circular polarizer based on the gap waveguide (GWG) technology. Two sets of symmetrical septum circular polarizers are used for common aperture combination,achieving the broadband dual-CP characteristics. Taking advantage of GWG structure without good electrical contact, the antenna can also be fabricated and assembled easily in the mmW band. The principle analysis of the antenna is given, and the antenna is simulated and fabricated. The measured results show that the bandwidth for S11lower than-10.7 dB and the axial ratio (AR) lower than 2.90 dB in 75-110 GHz, with realative bandwidth of 38%. Over the frequency band, the gain is higher than 9.16 dBic, and the dual-CP port isolation is greater than32 dB. The proposed antenna with dual-CP and highly isolated in a wide bandwidth range has broad application prospects in the field of mmW communication.展开更多
Separated transmit and receive antennas are employed to improve transmit-receive isolation in conventional short-range radars, which greatly increases the antenna size and misaligns of the transmit/receive radiation p...Separated transmit and receive antennas are employed to improve transmit-receive isolation in conventional short-range radars, which greatly increases the antenna size and misaligns of the transmit/receive radiation patterns. In this paper,a dual circularly polarized(CP) monostatic simultaneous transmit and receive(MSTAR) antenna with enhanced isolation is proposed to alleviate the problem. The proposed antenna consists of one sequentially rotating array(SRA), two beamforming networks(BFN), and a combined decoupling structure. The SRA is shared by the transmit and receive to reduce the size of the antenna and to obtain a consistent transmit and receive pattern.The BFN achieve right-hand CP for transmit and left-hand CP for receive. By exploring the combined decoupling structure of uniplanar compact electromagnetic band gap(UC-EBG) and ringshaped defected ground structure(RS-DGS), good transmitreceive isolation is achieved. The proposed antenna prototype is fabricated and experimentally characterized. The simulated and measured results show good agreement. The demonstrate transmit/receive isolation is height than 33 dB, voltage standing wave ratio is lower than 2, axial ratio is lower than 3 dB, and consistent radiation for both transmit and receive is within4.25-4.35 GHz.展开更多
Objective The detection of RNA single nucleotide polymorphism(SNP)is of great importance due to their association with protein expression related to various diseases and drug responses.At present,splintR ligase-assist...Objective The detection of RNA single nucleotide polymorphism(SNP)is of great importance due to their association with protein expression related to various diseases and drug responses.At present,splintR ligase-assisted methods are important approaches for RNA direct detection,but its specificity will be limited when the fidelity of ligases is not ideal.The aim of this study was to create a method to improve the specificity of splintR ligase for RNA detection.Methods In this study,a dualcompetitive-padlock-probe(DCPLP)assay without the need for additional enzymes or reactions is proposed to improve specificity of splintR ligase ligation.To verify the method,we employed dual competitive padlock probe-mediated rolling circle amplification(DCPLP-RCA)to genotype the CYP2C9 gene.Results The specificity was well improved through the competition and strand displacement of dual padlock probe,with an 83.26%reduction in nonspecific signal.By detecting synthetic RNA samples,the method demonstrated a dynamic detection range of 10 pmol/L-1 nmol/L.Furthermore,clinical samples were applied to the method to evaluate its performance,and the genotyping results were consistent with those obtained using the qPCR method.Conclusion This study has successfully established a highly specific direct RNA SNP detection method,and provided a novel avenue for accurate identification of various types of RNAs.展开更多
In this paper,a control scheme based on current optimization is proposed for dual three-phase permanent-magnet synchronous motor(DTP-PMSM)drive to reduce the low-frequency temperature swing.The reduction of temperatur...In this paper,a control scheme based on current optimization is proposed for dual three-phase permanent-magnet synchronous motor(DTP-PMSM)drive to reduce the low-frequency temperature swing.The reduction of temperature swing can be equivalent to reducing maximum instantaneous phase copper loss in this paper.First,a two-level optimization aiming at minimizing maximum instantaneous phase copper loss at each electrical angle is proposed.Then,the optimization is transformed to a singlelevel optimization by introducing the auxiliary variable for easy solving.Considering that singleobjective optimization trades a great total copper loss for a small reduction of maximum phase copper loss,the optimization considering both instantaneous total copper loss and maximum phase copper loss is proposed,which has the same performance of temperature swing reduction but with lower total loss.In this way,the proposed control scheme can reduce maximum junction temperature by 11%.Both simulation and experimental results are presented to prove the effectiveness and superiority of the proposed control scheme for low-frequency temperature swing reduction.展开更多
The irreversible phase transition and interface side reactions during the cycling process severely limit the large scale application of nickel-rich layered oxides Li[Ni_(x)Co_(y)Mn_(1−x−y)]O_(2)(NCM,x>0.8).Herein,w...The irreversible phase transition and interface side reactions during the cycling process severely limit the large scale application of nickel-rich layered oxides Li[Ni_(x)Co_(y)Mn_(1−x−y)]O_(2)(NCM,x>0.8).Herein,we have designed LiNi_(0.8)Co_(0.1)Mn 0.1 O_(2)cathodes modified by Nb/Al co-doping and LiNbO_(3)/LiAlO_(2)composite coating.Detailed characterization reveals that Nb/Al co-doping can stabilize the crystal structure of the cathodes and expand the layer spacing of the layered lattice,thereby increasing the diffusion rate and reversibility of Li^(+).And the composite coatings can improve the electrochemical kinetic and inhibit the erosion of acidic substances by hindering direct contact between the cathodes and electrolyte.As a result,the Ni-rich cathodes with dual modification can still exhibit a higher capacity of 184.02 mA·h/g after 100 cycles with a capacity retention of up to 98.1%,and can still release a capacity of 161.6 mA·h/g at a high rate of 7 C,meanwhile,it shows excellent thermal stability compared to bare NCM.This work provides a new perspective for enhancing electrochemical properties of cathodes through integrated strategies.展开更多
In this paper, a filtering method is presented to estimate time-varying parameters of a missile dual control system with tail fins and reaction jets as control variables. In this method, the long-short-term memory(LST...In this paper, a filtering method is presented to estimate time-varying parameters of a missile dual control system with tail fins and reaction jets as control variables. In this method, the long-short-term memory(LSTM) neural network is nested into the extended Kalman filter(EKF) to modify the Kalman gain such that the filtering performance is improved in the presence of large model uncertainties. To avoid the unstable network output caused by the abrupt changes of system states,an adaptive correction factor is introduced to correct the network output online. In the process of training the network, a multi-gradient descent learning mode is proposed to better fit the internal state of the system, and a rolling training is used to implement an online prediction logic. Based on the Lyapunov second method, we discuss the stability of the system, the result shows that when the training error of neural network is sufficiently small, the system is asymptotically stable. With its application to the estimation of time-varying parameters of a missile dual control system, the LSTM-EKF shows better filtering performance than the EKF and adaptive EKF(AEKF) when there exist large uncertainties in the system model.展开更多
基金supported by the National Natural Science Foundation of China(No.22375021,22235003,22261132516&22205021)the BIT Research and Innovation 265 Promoting Project(Grant No.2023YCXZ017)。
文摘Energetic compounds bearing the trinitromethyl group are garnering broad attraction as potential candidates for a new generation of high energy dense oxidizers.In this work,an effective dual modulation strategy involving both molecular isomerization and crystal morphology control was employed to design and optimize trinitromethyl-oxadiazole with improved comprehensive performance.Utilizing this dual strategy,3,5-bis(trinitromethyl)-1,2,4-oxadiazole(3)was synthesized,resulting in the formation of two distinct crystal morphologies(needle and sheet)corresponding to two crystal forms(3-a and3-b).Encouragingly,while maintaining ultra-high oxygen balance(21.73%),3 achieves impressive densities(1.97-1.98 g/cm^(3)).To our knowledge,the density of 1.98 g/cm^(3)for 3-a sets a new record among that of nitrogen-rich monocyclic compounds.Notably,practical crystal morphology prediction was creatively introduced to guide the experimental crystallization conditions of 3,increasing the impact sensitivity and friction sensitivity from 1 J to 80 N(3-a)to 10 J and 240 N(3-b),respectively.Additionally,the crystal structural analyses and theoretical calculations were conducted to elucidate the reasons of differences between 3-a and 3-b in density and stability.This work provides an efficient strategy to enhance performance of trinitromethyl derivatives,broadening the path and expanding the toolbox for energetic materials.
文摘A millimeter-wave (mmW) broadband dual circularly polarized (dual-CP) antenna with high port isolation is proposed in this paper. The dual-CP performance is realized based on the symmetrical septum circular polarizer based on the gap waveguide (GWG) technology. Two sets of symmetrical septum circular polarizers are used for common aperture combination,achieving the broadband dual-CP characteristics. Taking advantage of GWG structure without good electrical contact, the antenna can also be fabricated and assembled easily in the mmW band. The principle analysis of the antenna is given, and the antenna is simulated and fabricated. The measured results show that the bandwidth for S11lower than-10.7 dB and the axial ratio (AR) lower than 2.90 dB in 75-110 GHz, with realative bandwidth of 38%. Over the frequency band, the gain is higher than 9.16 dBic, and the dual-CP port isolation is greater than32 dB. The proposed antenna with dual-CP and highly isolated in a wide bandwidth range has broad application prospects in the field of mmW communication.
基金supported by Guangdong Natural Science Foundation(2019A1515011622)Guangdong Provincial Laboratory of Southern Marine Science and Engineering (Zhuhai)(SML2021SP407)。
文摘Separated transmit and receive antennas are employed to improve transmit-receive isolation in conventional short-range radars, which greatly increases the antenna size and misaligns of the transmit/receive radiation patterns. In this paper,a dual circularly polarized(CP) monostatic simultaneous transmit and receive(MSTAR) antenna with enhanced isolation is proposed to alleviate the problem. The proposed antenna consists of one sequentially rotating array(SRA), two beamforming networks(BFN), and a combined decoupling structure. The SRA is shared by the transmit and receive to reduce the size of the antenna and to obtain a consistent transmit and receive pattern.The BFN achieve right-hand CP for transmit and left-hand CP for receive. By exploring the combined decoupling structure of uniplanar compact electromagnetic band gap(UC-EBG) and ringshaped defected ground structure(RS-DGS), good transmitreceive isolation is achieved. The proposed antenna prototype is fabricated and experimentally characterized. The simulated and measured results show good agreement. The demonstrate transmit/receive isolation is height than 33 dB, voltage standing wave ratio is lower than 2, axial ratio is lower than 3 dB, and consistent radiation for both transmit and receive is within4.25-4.35 GHz.
文摘Objective The detection of RNA single nucleotide polymorphism(SNP)is of great importance due to their association with protein expression related to various diseases and drug responses.At present,splintR ligase-assisted methods are important approaches for RNA direct detection,but its specificity will be limited when the fidelity of ligases is not ideal.The aim of this study was to create a method to improve the specificity of splintR ligase for RNA detection.Methods In this study,a dualcompetitive-padlock-probe(DCPLP)assay without the need for additional enzymes or reactions is proposed to improve specificity of splintR ligase ligation.To verify the method,we employed dual competitive padlock probe-mediated rolling circle amplification(DCPLP-RCA)to genotype the CYP2C9 gene.Results The specificity was well improved through the competition and strand displacement of dual padlock probe,with an 83.26%reduction in nonspecific signal.By detecting synthetic RNA samples,the method demonstrated a dynamic detection range of 10 pmol/L-1 nmol/L.Furthermore,clinical samples were applied to the method to evaluate its performance,and the genotyping results were consistent with those obtained using the qPCR method.Conclusion This study has successfully established a highly specific direct RNA SNP detection method,and provided a novel avenue for accurate identification of various types of RNAs.
基金supported by the National Natural Science Foundation of China(No.62271109)。
文摘In this paper,a control scheme based on current optimization is proposed for dual three-phase permanent-magnet synchronous motor(DTP-PMSM)drive to reduce the low-frequency temperature swing.The reduction of temperature swing can be equivalent to reducing maximum instantaneous phase copper loss in this paper.First,a two-level optimization aiming at minimizing maximum instantaneous phase copper loss at each electrical angle is proposed.Then,the optimization is transformed to a singlelevel optimization by introducing the auxiliary variable for easy solving.Considering that singleobjective optimization trades a great total copper loss for a small reduction of maximum phase copper loss,the optimization considering both instantaneous total copper loss and maximum phase copper loss is proposed,which has the same performance of temperature swing reduction but with lower total loss.In this way,the proposed control scheme can reduce maximum junction temperature by 11%.Both simulation and experimental results are presented to prove the effectiveness and superiority of the proposed control scheme for low-frequency temperature swing reduction.
基金Project(2023JJ40759)supported by the Natural Science Foundation of Hunan Province,China。
文摘The irreversible phase transition and interface side reactions during the cycling process severely limit the large scale application of nickel-rich layered oxides Li[Ni_(x)Co_(y)Mn_(1−x−y)]O_(2)(NCM,x>0.8).Herein,we have designed LiNi_(0.8)Co_(0.1)Mn 0.1 O_(2)cathodes modified by Nb/Al co-doping and LiNbO_(3)/LiAlO_(2)composite coating.Detailed characterization reveals that Nb/Al co-doping can stabilize the crystal structure of the cathodes and expand the layer spacing of the layered lattice,thereby increasing the diffusion rate and reversibility of Li^(+).And the composite coatings can improve the electrochemical kinetic and inhibit the erosion of acidic substances by hindering direct contact between the cathodes and electrolyte.As a result,the Ni-rich cathodes with dual modification can still exhibit a higher capacity of 184.02 mA·h/g after 100 cycles with a capacity retention of up to 98.1%,and can still release a capacity of 161.6 mA·h/g at a high rate of 7 C,meanwhile,it shows excellent thermal stability compared to bare NCM.This work provides a new perspective for enhancing electrochemical properties of cathodes through integrated strategies.
文摘In this paper, a filtering method is presented to estimate time-varying parameters of a missile dual control system with tail fins and reaction jets as control variables. In this method, the long-short-term memory(LSTM) neural network is nested into the extended Kalman filter(EKF) to modify the Kalman gain such that the filtering performance is improved in the presence of large model uncertainties. To avoid the unstable network output caused by the abrupt changes of system states,an adaptive correction factor is introduced to correct the network output online. In the process of training the network, a multi-gradient descent learning mode is proposed to better fit the internal state of the system, and a rolling training is used to implement an online prediction logic. Based on the Lyapunov second method, we discuss the stability of the system, the result shows that when the training error of neural network is sufficiently small, the system is asymptotically stable. With its application to the estimation of time-varying parameters of a missile dual control system, the LSTM-EKF shows better filtering performance than the EKF and adaptive EKF(AEKF) when there exist large uncertainties in the system model.
