Low profile and light weight are very important for practical applications of a spoof surface plasmon polariton（SSPP）coupler, especially at low frequencies. In this paper, we propose and design an ultra-thin, light-...Low profile and light weight are very important for practical applications of a spoof surface plasmon polariton（SSPP）coupler, especially at low frequencies. In this paper, we propose and design an ultra-thin, light-weight SSPP coupler based on broadside coupled split ring resonators（BC-SRRs）. The size of BC-SRR can be far less than λ/100 and can extremely well control the reflective phases within a subwavelength thickness. Due to the broadside capacitive coupling, the electrical size of BC-SRR is dramatically reduced to guarantee the ultra-thin thickness of the SSPP coupler. The weight of the SSPP coupler is reduced by a low occupation ratio of BC-SRR in the unit cell volume. As an example, a C-band SSPP coupler composed of phase gradient BC-SRRs is designed, fabricated, and measured. Due to the ultra-small size and low occupation ratio of BC-SRRs, the thickness of the coupler is λ/12 and the surface density is only 0.98 kg/m^2. Both simulation and experiment results verify that the coupler can achieve high-efficiency SPP coupling at 5.27 GHz under normal incidence.展开更多
To solve the problem of realizing autonomous aerial combat decision-making for unmanned combat aerial vehicles(UCAVs) rapidly and accurately in an uncertain environment, this paper proposes a decision-making method ba...To solve the problem of realizing autonomous aerial combat decision-making for unmanned combat aerial vehicles(UCAVs) rapidly and accurately in an uncertain environment, this paper proposes a decision-making method based on an improved deep reinforcement learning(DRL) algorithm: the multistep double deep Q-network(MS-DDQN) algorithm. First, a six-degree-of-freedom UCAV model based on an aircraft control system is established on a simulation platform, and the situation assessment functions of the UCAV and its target are established by considering their angles, altitudes, environments, missile attack performances, and UCAV performance. By controlling the flight path angle, roll angle, and flight velocity, 27 common basic actions are designed. On this basis, aiming to overcome the defects of traditional DRL in terms of training speed and convergence speed, the improved MS-DDQN method is introduced to incorporate the final return value into the previous steps. Finally, the pre-training learning model is used as the starting point for the second learning model to simulate the UCAV aerial combat decision-making process based on the basic training method, which helps to shorten the training time and improve the learning efficiency. The improved DRL algorithm significantly accelerates the training speed and estimates the target value more accurately during training, and it can be applied to aerial combat decision-making.展开更多
A hydrogen-plasma-etching-based plasma-enhanced chemical vapor deposition(PECVD)synthesis route without metal catalyst for preparing the graphene films on flexible glass is developed.The quality of the prepared graphe...A hydrogen-plasma-etching-based plasma-enhanced chemical vapor deposition(PECVD)synthesis route without metal catalyst for preparing the graphene films on flexible glass is developed.The quality of the prepared graphene films is evaluated by scanning electron microscopy,x-ray photoelectron spectroscopy,high-resolution transmission electron microscopy,ultraviolet-visible spectroscopy,and electrochemical measurements.In a radio frequency(RF)power range of 50 W-300 W,the graphene growth rate increases with RF power increasing,while the intensity ratio of D-to G-Raman peak(I_(D)/I_(G))decreases.When the RF power is higher than 300 W,the I_(D)/I_(G)rises again.By optimizing experimental parameters of hydrogen plasma etching and RF power,the properties of as-prepared flexible graphene on glass are modulated to be able to achieve the graphene's transparency,good electrical conductivity,and better macroscopic uniformity.Direct growth of graphene film without any metal catalyst on flexible glass can be a promising candidate for applications in flexible transparent optoelectronics.展开更多
Vortex beams carrying orbital angular momentum(OAM)have aroused great interest of both scientific and engineering communities.Encouragingly,generating OAM with different topological charges in a shared aperture is reg...Vortex beams carrying orbital angular momentum(OAM)have aroused great interest of both scientific and engineering communities.Encouragingly,generating OAM with different topological charges in a shared aperture is regarded as a potential route to expanding the communication capacity,which yet is an academic challenging task.In this work,a paradigm of designing metasurface-based shared aperture antenna for generating polarization-dependent vortex beams with distinct topological charges is proposed.Anisotropic unit cells that can tailor different resonance phase profiles in two orthogonal orientations are used to assemble a metasurface reflector.As a proof-of-concept,a planar reflector antenna is designed with two Vivaldi sources,which can generate x-and y-polarized vortex beams with topological charges of l=-1 and l=-2,respectively.Both the simulation results and the measurement results are in good agreement,which demonstrates the feasibility of our design.Significantly,this work provides a new route to achieving vortex beams carrying different topological charges in the same frequency band,which may have potential applications in communication systems.展开更多
Objective:To study the effect of minimally invasive evacuation of hematoma combined with Xingnaojing therapy on neurological function damage and cytokine level in patients with hypertensive cerebral hemorrhage.Methods...Objective:To study the effect of minimally invasive evacuation of hematoma combined with Xingnaojing therapy on neurological function damage and cytokine level in patients with hypertensive cerebral hemorrhage.Methods:A total of 80 patients with hypertensive cerebral hemorrhage treated in our hospital between June 2010 and September 2015 were selected as the research subjects, the treatment methods and test results were reviewed, and then they were divided into the control group (n=45) who accepted minimally invasive evacuation of hematoma alone and the observation group (n=35) who accepted minimally invasive evacuation of hematoma combined with Xingnaojing therapy. Before and after treatment, cerebral blood flow detector was used to detect cerebral blood flow parameters;ELISA method was used to detect serum levels of neurological function indexes and inflammatory cytokines;high performance liquid chromatograph was used to detect serum neurotransmitter levels. Results: Before treatment, the differences in cerebral blood flow parameters, neurological function indexes, inflammatory cytokines and neurotransmitters were not statistically significant between two groups of patients. After treatment, cerebral blood flow parameters Q and V levels of observation group were higher than those of control group while R level was lower than that of control group;serum NSE, NPY, IL-1β, IL-4, IL-6, TNF-α, Glu and Asp contents of observation group were lower than those of control group while BDNF and Gly contents were higher than those of control group.Conclusion: Minimally invasive evacuation of hematoma combined with Xingnaojing therapy can improve the neurological function and regulate the synthesis of inflammatory cytokines and neurotransmitters in patients with hypertension cerebral hemorrhage.展开更多
Mixtures of W and B13C2 powders were mechanically milled and subsequently annealed at 900-1200℃.It is found that amorphous W-B-C alloy formed as the mixtures were milled for 20.80 h.After annealing the 80 h-milled mi...Mixtures of W and B13C2 powders were mechanically milled and subsequently annealed at 900-1200℃.It is found that amorphous W-B-C alloy formed as the mixtures were milled for 20.80 h.After annealing the 80 h-milled mixtures at 900-950℃,solid solutions of C and/or B in tungsten[W（B,C）],C in tungsten boride[W2B（C）or WB（C）]formed by the crystallization of amorphous W-B-C.The formation temperature of W2B（C）and WB（C）is lower than that of W2B and WB reported previously.As the 80 h-milled mixtures were annealed at 1200℃,W reacted with amorphous W-B-C completely to form WB and W2B5 or W2B5 instead of the solid solutions of C in tungsten borides,which is determined by the mole ratio of W to B13C2.The formation mechanisms of the W2B（C）and WB（C）solid solutions as well as phase transition rules of the mixtures at annealing temperature and mole ratio were also investigated using first-principle calculation.展开更多
Objective:Pain is a health problem frequently reported in the clinical and general populations.Acupoint therapy is one of the most effective ways to treat pain;however,its mechanism remains unclear.Therefore,this stud...Objective:Pain is a health problem frequently reported in the clinical and general populations.Acupoint therapy is one of the most effective ways to treat pain;however,its mechanism remains unclear.Therefore,this study aimed to explore the relationship between distal acupoints,dorsal root ganglion(DRG)neurons,and spinal cord dorsal horn(SDH) neurons in neck acute inflammatory pain(NAIP).Methods:NAIP model rats were used to explore the relationship between acupoint sensitization and pain.Out of fourteen rats,ten rats were grouped into control and NAIP groups,five rats in control and five rats in NAIP.Mustard oil was subcutaneously injected on one side between the C4 and C7 vertebrae of the neck to establish an NAIP model.Evans blue(EB) was injected through the tail vein to detect sensitized acupoints after NAIP modeling.EB exudation in the body,Liè qūe(列缺 LU7),and Língdào(灵道 HT4) were evaluated.An immunofluorescence assay was conducted to detect the expression of calcitonin generelated peptide(CGRP),isolectin B4(IB4),and c-Fos in the dorsal root ganglion(DRG)and spinal cord dorsal medullae spinalis(CDMS).Four rats were used for the retrograde labeling of neurons of the LU7 region to the DRG and CDMS using CTB-488 and CTB-555 microinjection.Results:NAIP was shown to lead to oozing and pain sensitization in the LU7 and HT4 and increased the proportion of c-Fos^(+)/CGRP^(+)and c-Fos^(+)/IB4^(+)cells in both the DRG and CDMS.CTB-488 and CTB-555injected into the LU7 and sensitization point areas were observed in the DRG and CDMS regions of NAIP rats.Conclusions:Our study revealed that NAIP could lead to oozing and pain sensitization in the LU7 and HT4regions and that the pain point around LU7 might result from the transfer of peptidergic(CGRP-positive)and non-peptidergic(IB4-positive) neurons in the DRG and CDMS.展开更多
In this study, the effect of wheel speed and mischmetal（MM） content on the magnetic properties of MMFeB ribbons was investigated. The samples were prepared via direct solidification technique. The nominal compositio...In this study, the effect of wheel speed and mischmetal（MM） content on the magnetic properties of MMFeB ribbons was investigated. The samples were prepared via direct solidification technique. The nominal composition of the alloy ingots is MM;Fe;B;with x varying from 9 to 15 in steps of 2. Experimental results show the overall magnetic properties of the ribbons.Analysis of the results shows that the magnetic properties first improve and then degrade with the wheel speed and MM content increasing. Increase in MM content leads to better formation of crystal texture in the ribbons, indicating that the a-Fe phase might undermine the formation of crystal texture. Magnetic properties results show that the coercivity of the ribbons rises with an appropriate increase in both MM content and wheel speed during melt-spun process. The strongest magnetic properties of the ribbons(remanence of M;= 0.72 T, intrinsic coercivity of H;= 352.58 kA·m;, and maximum energy product of（BH）;=72.14 kJ·m;) are obtained for compositions where x = 13 and a wheel speed of v = 20 m·s;.展开更多
The magnetic properties and microstructure of sintered R-Fe-B（R, rare earth） magnets with nominal composition of（（PrNd）（1-x）MMx）（30）Fe（bal）B1（x = 0, 0.1.0.2,0.3, 0.4, 0.5 and 0.7; MM, misch metal） prepar...The magnetic properties and microstructure of sintered R-Fe-B（R, rare earth） magnets with nominal composition of（（PrNd）（1-x）MMx）（30）Fe（bal）B1（x = 0, 0.1.0.2,0.3, 0.4, 0.5 and 0.7; MM, misch metal） prepared using dual-alloy method were investigated. For x = 0.3, the maximum energy product（（BH）（max）） of the sintered magnet is higher than 318.4 kJ·m^-3,but intrinsic coercivity（H（cj）） is lower than 351.8 kA·m^-1. The La and Ce contents are obviously different in some matrix-phase grains, which proves that the multi-hard magnetic phases（La, Ce-rich and La, Ce-lean） exist in the magnets. The coercivity is improved by the method of doping PrNd nanoparticles without sacrificing other magnetic properties. An enhancement in coercivity from 517.2 to 872.9 kA·m^-1 is achieved by doping 5 wt% PrNd nanoparticles. Meanwhile, it could exhibit better magnetic properties（remanence Br = 1.332 T.intrinsic coercivity H（cj）= 872.9 kA·m^-1 maximum energy product（BH）（max）=318.6 kJ·m^-3） and make the distribution of the intergranular phase become more homogeneous.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61331005,61471388,and 61501503)
文摘Low profile and light weight are very important for practical applications of a spoof surface plasmon polariton（SSPP）coupler, especially at low frequencies. In this paper, we propose and design an ultra-thin, light-weight SSPP coupler based on broadside coupled split ring resonators（BC-SRRs）. The size of BC-SRR can be far less than λ/100 and can extremely well control the reflective phases within a subwavelength thickness. Due to the broadside capacitive coupling, the electrical size of BC-SRR is dramatically reduced to guarantee the ultra-thin thickness of the SSPP coupler. The weight of the SSPP coupler is reduced by a low occupation ratio of BC-SRR in the unit cell volume. As an example, a C-band SSPP coupler composed of phase gradient BC-SRRs is designed, fabricated, and measured. Due to the ultra-small size and low occupation ratio of BC-SRRs, the thickness of the coupler is λ/12 and the surface density is only 0.98 kg/m^2. Both simulation and experiment results verify that the coupler can achieve high-efficiency SPP coupling at 5.27 GHz under normal incidence.
基金supported by the National Natural Science Foundation of China (No. 61573286)the Aeronautical Science Foundation of China (No. 20180753006)+2 种基金the Fundamental Research Funds for the Central Universities (3102019ZDHKY07)the Natural Science Foundation of Shaanxi Province (2019JM-163, 2020JQ-218)the Shaanxi Province Key Laboratory of Flight Control and Simulation Technology。
文摘To solve the problem of realizing autonomous aerial combat decision-making for unmanned combat aerial vehicles(UCAVs) rapidly and accurately in an uncertain environment, this paper proposes a decision-making method based on an improved deep reinforcement learning(DRL) algorithm: the multistep double deep Q-network(MS-DDQN) algorithm. First, a six-degree-of-freedom UCAV model based on an aircraft control system is established on a simulation platform, and the situation assessment functions of the UCAV and its target are established by considering their angles, altitudes, environments, missile attack performances, and UCAV performance. By controlling the flight path angle, roll angle, and flight velocity, 27 common basic actions are designed. On this basis, aiming to overcome the defects of traditional DRL in terms of training speed and convergence speed, the improved MS-DDQN method is introduced to incorporate the final return value into the previous steps. Finally, the pre-training learning model is used as the starting point for the second learning model to simulate the UCAV aerial combat decision-making process based on the basic training method, which helps to shorten the training time and improve the learning efficiency. The improved DRL algorithm significantly accelerates the training speed and estimates the target value more accurately during training, and it can be applied to aerial combat decision-making.
基金Project supported by the National Natural Science Foundation of China(Grant No.51302215)the Joint Research Funds of Department of Science&Technology of Shaanxi Province and Northwestern Polytechnical University,China(Grant No.2020GXLH-Z-029)the Natural Science Basic Research Program of Shaanxi Province,China(Grant Nos.2018JQ6084 and 2019JQ-860).
文摘A hydrogen-plasma-etching-based plasma-enhanced chemical vapor deposition(PECVD)synthesis route without metal catalyst for preparing the graphene films on flexible glass is developed.The quality of the prepared graphene films is evaluated by scanning electron microscopy,x-ray photoelectron spectroscopy,high-resolution transmission electron microscopy,ultraviolet-visible spectroscopy,and electrochemical measurements.In a radio frequency(RF)power range of 50 W-300 W,the graphene growth rate increases with RF power increasing,while the intensity ratio of D-to G-Raman peak(I_(D)/I_(G))decreases.When the RF power is higher than 300 W,the I_(D)/I_(G)rises again.By optimizing experimental parameters of hydrogen plasma etching and RF power,the properties of as-prepared flexible graphene on glass are modulated to be able to achieve the graphene's transparency,good electrical conductivity,and better macroscopic uniformity.Direct growth of graphene film without any metal catalyst on flexible glass can be a promising candidate for applications in flexible transparent optoelectronics.
基金Project supported by the National Natural Science foundation of China(Grant No.61971347).
文摘Vortex beams carrying orbital angular momentum(OAM)have aroused great interest of both scientific and engineering communities.Encouragingly,generating OAM with different topological charges in a shared aperture is regarded as a potential route to expanding the communication capacity,which yet is an academic challenging task.In this work,a paradigm of designing metasurface-based shared aperture antenna for generating polarization-dependent vortex beams with distinct topological charges is proposed.Anisotropic unit cells that can tailor different resonance phase profiles in two orthogonal orientations are used to assemble a metasurface reflector.As a proof-of-concept,a planar reflector antenna is designed with two Vivaldi sources,which can generate x-and y-polarized vortex beams with topological charges of l=-1 and l=-2,respectively.Both the simulation results and the measurement results are in good agreement,which demonstrates the feasibility of our design.Significantly,this work provides a new route to achieving vortex beams carrying different topological charges in the same frequency band,which may have potential applications in communication systems.
文摘Objective:To study the effect of minimally invasive evacuation of hematoma combined with Xingnaojing therapy on neurological function damage and cytokine level in patients with hypertensive cerebral hemorrhage.Methods:A total of 80 patients with hypertensive cerebral hemorrhage treated in our hospital between June 2010 and September 2015 were selected as the research subjects, the treatment methods and test results were reviewed, and then they were divided into the control group (n=45) who accepted minimally invasive evacuation of hematoma alone and the observation group (n=35) who accepted minimally invasive evacuation of hematoma combined with Xingnaojing therapy. Before and after treatment, cerebral blood flow detector was used to detect cerebral blood flow parameters;ELISA method was used to detect serum levels of neurological function indexes and inflammatory cytokines;high performance liquid chromatograph was used to detect serum neurotransmitter levels. Results: Before treatment, the differences in cerebral blood flow parameters, neurological function indexes, inflammatory cytokines and neurotransmitters were not statistically significant between two groups of patients. After treatment, cerebral blood flow parameters Q and V levels of observation group were higher than those of control group while R level was lower than that of control group;serum NSE, NPY, IL-1β, IL-4, IL-6, TNF-α, Glu and Asp contents of observation group were lower than those of control group while BDNF and Gly contents were higher than those of control group.Conclusion: Minimally invasive evacuation of hematoma combined with Xingnaojing therapy can improve the neurological function and regulate the synthesis of inflammatory cytokines and neurotransmitters in patients with hypertension cerebral hemorrhage.
基金supported by the National Natural Science Foundation of China(Grant Nos.11274135,11074093,61205038)the Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20130061130011)+2 种基金the Ph.D Programs Foundation of Ministry of Education of China(Grant No.20120061120011)the Science and Technology Development Project of Jilin Province,China(Grant No.20170101142JC)supported by High Performance Computing Center of Jilin University,China
文摘Mixtures of W and B13C2 powders were mechanically milled and subsequently annealed at 900-1200℃.It is found that amorphous W-B-C alloy formed as the mixtures were milled for 20.80 h.After annealing the 80 h-milled mixtures at 900-950℃,solid solutions of C and/or B in tungsten[W（B,C）],C in tungsten boride[W2B（C）or WB（C）]formed by the crystallization of amorphous W-B-C.The formation temperature of W2B（C）and WB（C）is lower than that of W2B and WB reported previously.As the 80 h-milled mixtures were annealed at 1200℃,W reacted with amorphous W-B-C completely to form WB and W2B5 or W2B5 instead of the solid solutions of C in tungsten borides,which is determined by the mole ratio of W to B13C2.The formation mechanisms of the W2B（C）and WB（C）solid solutions as well as phase transition rules of the mixtures at annealing temperature and mole ratio were also investigated using first-principle calculation.
基金Supported by the National Key Research and Development Program of China:2018YFC1704606。
文摘Objective:Pain is a health problem frequently reported in the clinical and general populations.Acupoint therapy is one of the most effective ways to treat pain;however,its mechanism remains unclear.Therefore,this study aimed to explore the relationship between distal acupoints,dorsal root ganglion(DRG)neurons,and spinal cord dorsal horn(SDH) neurons in neck acute inflammatory pain(NAIP).Methods:NAIP model rats were used to explore the relationship between acupoint sensitization and pain.Out of fourteen rats,ten rats were grouped into control and NAIP groups,five rats in control and five rats in NAIP.Mustard oil was subcutaneously injected on one side between the C4 and C7 vertebrae of the neck to establish an NAIP model.Evans blue(EB) was injected through the tail vein to detect sensitized acupoints after NAIP modeling.EB exudation in the body,Liè qūe(列缺 LU7),and Língdào(灵道 HT4) were evaluated.An immunofluorescence assay was conducted to detect the expression of calcitonin generelated peptide(CGRP),isolectin B4(IB4),and c-Fos in the dorsal root ganglion(DRG)and spinal cord dorsal medullae spinalis(CDMS).Four rats were used for the retrograde labeling of neurons of the LU7 region to the DRG and CDMS using CTB-488 and CTB-555 microinjection.Results:NAIP was shown to lead to oozing and pain sensitization in the LU7 and HT4 and increased the proportion of c-Fos^(+)/CGRP^(+)and c-Fos^(+)/IB4^(+)cells in both the DRG and CDMS.CTB-488 and CTB-555injected into the LU7 and sensitization point areas were observed in the DRG and CDMS regions of NAIP rats.Conclusions:Our study revealed that NAIP could lead to oozing and pain sensitization in the LU7 and HT4regions and that the pain point around LU7 might result from the transfer of peptidergic(CGRP-positive)and non-peptidergic(IB4-positive) neurons in the DRG and CDMS.
基金financially supported by the National Natural Science Foundation of China (Nos. 51461033, 51571126, 51541105, and 11547032)the Inner Mongolia Innovative Research Team (No. 3400102)+3 种基金the Inner Mongolia Science Foundation (No. 2013MS0110)the Provincial Major Science and Technology Project of Inner Mongolia (No. 2009J1006)the Baotou Major Research Project Special for Rare Earth (No. 2012R1006)the Inner Mongolia University of Science and Technology Innovation Fund
文摘In this study, the effect of wheel speed and mischmetal（MM） content on the magnetic properties of MMFeB ribbons was investigated. The samples were prepared via direct solidification technique. The nominal composition of the alloy ingots is MM;Fe;B;with x varying from 9 to 15 in steps of 2. Experimental results show the overall magnetic properties of the ribbons.Analysis of the results shows that the magnetic properties first improve and then degrade with the wheel speed and MM content increasing. Increase in MM content leads to better formation of crystal texture in the ribbons, indicating that the a-Fe phase might undermine the formation of crystal texture. Magnetic properties results show that the coercivity of the ribbons rises with an appropriate increase in both MM content and wheel speed during melt-spun process. The strongest magnetic properties of the ribbons(remanence of M;= 0.72 T, intrinsic coercivity of H;= 352.58 kA·m;, and maximum energy product of（BH）;=72.14 kJ·m;) are obtained for compositions where x = 13 and a wheel speed of v = 20 m·s;.
基金financially supported by the National Key Research and Development Program of China (No.2016YFB0700903)the National Natural Science Foundation of China (No.51571126)+3 种基金the Inner Mongolia Innovative Research Team(No.3400102)the Innovative Science and Technology Project of Inner Mongolia (No.4140300502)the Science and Technology Project of Baotou (Nos.2012R1006 and 2015C2006-13)the Science and Technology Innovation Project of University (No.2014QDL003)
文摘The magnetic properties and microstructure of sintered R-Fe-B（R, rare earth） magnets with nominal composition of（（PrNd）（1-x）MMx）（30）Fe（bal）B1（x = 0, 0.1.0.2,0.3, 0.4, 0.5 and 0.7; MM, misch metal） prepared using dual-alloy method were investigated. For x = 0.3, the maximum energy product（（BH）（max）） of the sintered magnet is higher than 318.4 kJ·m^-3,but intrinsic coercivity（H（cj）） is lower than 351.8 kA·m^-1. The La and Ce contents are obviously different in some matrix-phase grains, which proves that the multi-hard magnetic phases（La, Ce-rich and La, Ce-lean） exist in the magnets. The coercivity is improved by the method of doping PrNd nanoparticles without sacrificing other magnetic properties. An enhancement in coercivity from 517.2 to 872.9 kA·m^-1 is achieved by doping 5 wt% PrNd nanoparticles. Meanwhile, it could exhibit better magnetic properties（remanence Br = 1.332 T.intrinsic coercivity H（cj）= 872.9 kA·m^-1 maximum energy product（BH）（max）=318.6 kJ·m^-3） and make the distribution of the intergranular phase become more homogeneous.
