Rehabilitation engineering aims in the upmost degree to restore the lost functions for those persons with physical disability. Biomechanical modeling has been widely used for different purposes in rehabilitation engin...Rehabilitation engineering aims in the upmost degree to restore the lost functions for those persons with physical disability. Biomechanical modeling has been widely used for different purposes in rehabilitation engineering to understand the bio-展开更多
A MgO/biochar composite(MBC)with a wide range of pore sizes was prepared by a MgCl_(2)-NaOH co-impregnation method using lavender stalks as the biochar source,which can effectively remove Pb(Ⅱ)and Cd(Ⅱ)from wastewat...A MgO/biochar composite(MBC)with a wide range of pore sizes was prepared by a MgCl_(2)-NaOH co-impregnation method using lavender stalks as the biochar source,which can effectively remove Pb(Ⅱ)and Cd(Ⅱ)from wastewater.The co-impregnation treatment resulted in a specific surface area of the MBC that was approximately 54 times greater than that of the biochar derived from untreated stalks.The ion-exchange capacity of MBC was increased by the incorporation of MgO nanoparticles,which increased the alkali metal ion(Mg2+)content.These specific structures and compositions gave the MBC a high adsorption capacity for Pb(Ⅱ)and Cd(Ⅱ).The adsorption data followed a quasi second-order kinetic model.For Cd(Ⅱ)and Pb(Ⅱ),the maximum adsorption capacities of MBC-700(treated at 700℃for 2 h)reached 520 mg/g and 808 mg/g,respectively.The primary adsorption mechanisms were ion exchange,precipitation,electrostatic attraction and surface complexation.Furthermore,metallic lead was recovered by using the reducing properties of the biochar at high temperatures.This study provides a reference for developing inexpensive and efficient heavy metal adsorbents and the low-carbonization utilization of biomass waste.展开更多
Metasurfaces are artificial structures that can finely control the characteristics of electromagnetic waves at subwavelength scales,and they are widely used to manipulate the propagation,phase,amplitude,and polariza⁃t...Metasurfaces are artificial structures that can finely control the characteristics of electromagnetic waves at subwavelength scales,and they are widely used to manipulate the propagation,phase,amplitude,and polariza⁃tion of light.In this work,a bound state in the continuum(BIC)structure based on a metallic metasurface is pro⁃posed.By adjusting the metallic structure using CST and COMSOL software,a significant quasi-BIC peak can be achieved at a frequency of 0.8217 terahertz(THz).Through multi-level expansion analysis,it is found that the electric dipole(ED)is the main factor contributing to the resonant characteristics of the structure.By leveraging the characteristics of BIC,an imaging system was created and operated.According to the simulation results,the imaging system demonstrated excellent sensitivity and resolution,revealing the great potential of terahertz imag⁃ing.This research not only provides new ideas for the creation of BIC structures but also offers an effective refer⁃ence for the development of high-performance terahertz imaging technology.展开更多
随着6G移动通信技术的发展,通信与感知一体化(integrated sensing and communication,ISAC)成为未来无线网络的重要方向。在大规模分布式场景中,高精度定位仍面临计算和通信开销过大、参数不可靠等挑战。为此,提出一种多级融合的ISAC定...随着6G移动通信技术的发展,通信与感知一体化(integrated sensing and communication,ISAC)成为未来无线网络的重要方向。在大规模分布式场景中,高精度定位仍面临计算和通信开销过大、参数不可靠等挑战。为此,提出一种多级融合的ISAC定位架构:在接入点(access point,AP)级对感知信号进行预处理,并将结果上传至边缘分布式单元(edge distributed unit,EDU);EDU级利用神经网络将信噪比映射为时延参数的权重,并结合几何精度因子(geometric dilution of precision,GDOP)策略进行加权最小二乘局部定位;中央处理单元(central processing unit,CPU)级则在全局视角下对EDU上传的可靠参数进行二次动态筛选与最终定位。仿真结果表明,该架构能显著降低整体区域内的定位误差,通信和计算开销均优于集中式方案,具有良好的系统可扩展性。展开更多
合法通信双方可以利用无线信道状态的随机特性提取符合信息论安全的共享密钥序列。为了提高无线信道提取密钥的效率,提出一种基于差分的多级量化共享密钥提取方案。该方案采用随机调制对无线信道进行高频采样,并引入融合随机抽样差分的...合法通信双方可以利用无线信道状态的随机特性提取符合信息论安全的共享密钥序列。为了提高无线信道提取密钥的效率,提出一种基于差分的多级量化共享密钥提取方案。该方案采用随机调制对无线信道进行高频采样,并引入融合随机抽样差分的自适应符号量化(ASQ)和均衡化多比特修正量化(BMMQ)这2个算法处理一阶差分序列,以获得原始密钥序列。在此基础上,应用信息协商算法纠正原始密钥中不一致的比特,并使用原始密钥及一阶差分序列重构信号,再对该信号进行二次量化,最终实现合法通信双方的密钥同步。实验结果表明,随机抽样差分能够将相邻样本点之间的相关系数降低至e^(-1)以下,有效降低密钥序列中的统计依赖性;在信噪比(SNR)为25 dB的条件下,ASQ算法可在保持原始密钥提取率(OKER)为0.86的同时,将密钥不一致率(KDR)降低至3.8×10^(-5);在无损量化的条件下,BMMQ算法可以把KDR降低至7×10^(-3)。最终生成的共享密钥序列通过了NIST(National Institute of Standards and Technology)随机性测试,验证了密钥的安全性和有效性。展开更多
基金Research Grant Council of Hong Kong (GRF Project nos PolyU5331 /07E,PolyU5352 /08E)a grant from Ministry of Sciences and Technology,China (No 2006BAI22B00)
文摘Rehabilitation engineering aims in the upmost degree to restore the lost functions for those persons with physical disability. Biomechanical modeling has been widely used for different purposes in rehabilitation engineering to understand the bio-
基金funded by the National Natural Science Foundation of China(52563033)Xinjiang Natural Science Fund for Distinguished Young Scholars(2022D01E37)+1 种基金Xinjiang Tianshan Talent Project(2024TSYCCX0007)Key programs of Xinjiang Natural Science Foundation(2022B02051,2023B2045 and 2024LQ01001-3).
文摘A MgO/biochar composite(MBC)with a wide range of pore sizes was prepared by a MgCl_(2)-NaOH co-impregnation method using lavender stalks as the biochar source,which can effectively remove Pb(Ⅱ)and Cd(Ⅱ)from wastewater.The co-impregnation treatment resulted in a specific surface area of the MBC that was approximately 54 times greater than that of the biochar derived from untreated stalks.The ion-exchange capacity of MBC was increased by the incorporation of MgO nanoparticles,which increased the alkali metal ion(Mg2+)content.These specific structures and compositions gave the MBC a high adsorption capacity for Pb(Ⅱ)and Cd(Ⅱ).The adsorption data followed a quasi second-order kinetic model.For Cd(Ⅱ)and Pb(Ⅱ),the maximum adsorption capacities of MBC-700(treated at 700℃for 2 h)reached 520 mg/g and 808 mg/g,respectively.The primary adsorption mechanisms were ion exchange,precipitation,electrostatic attraction and surface complexation.Furthermore,metallic lead was recovered by using the reducing properties of the biochar at high temperatures.This study provides a reference for developing inexpensive and efficient heavy metal adsorbents and the low-carbonization utilization of biomass waste.
基金supported by the National Natural Science Foundation of China(61927813,61865009,12104203)Jiangxi Provincial Natu-ral Science Foundation(20212ACB201007)。
文摘Metasurfaces are artificial structures that can finely control the characteristics of electromagnetic waves at subwavelength scales,and they are widely used to manipulate the propagation,phase,amplitude,and polariza⁃tion of light.In this work,a bound state in the continuum(BIC)structure based on a metallic metasurface is pro⁃posed.By adjusting the metallic structure using CST and COMSOL software,a significant quasi-BIC peak can be achieved at a frequency of 0.8217 terahertz(THz).Through multi-level expansion analysis,it is found that the electric dipole(ED)is the main factor contributing to the resonant characteristics of the structure.By leveraging the characteristics of BIC,an imaging system was created and operated.According to the simulation results,the imaging system demonstrated excellent sensitivity and resolution,revealing the great potential of terahertz imag⁃ing.This research not only provides new ideas for the creation of BIC structures but also offers an effective refer⁃ence for the development of high-performance terahertz imaging technology.
文摘合法通信双方可以利用无线信道状态的随机特性提取符合信息论安全的共享密钥序列。为了提高无线信道提取密钥的效率,提出一种基于差分的多级量化共享密钥提取方案。该方案采用随机调制对无线信道进行高频采样,并引入融合随机抽样差分的自适应符号量化(ASQ)和均衡化多比特修正量化(BMMQ)这2个算法处理一阶差分序列,以获得原始密钥序列。在此基础上,应用信息协商算法纠正原始密钥中不一致的比特,并使用原始密钥及一阶差分序列重构信号,再对该信号进行二次量化,最终实现合法通信双方的密钥同步。实验结果表明,随机抽样差分能够将相邻样本点之间的相关系数降低至e^(-1)以下,有效降低密钥序列中的统计依赖性;在信噪比(SNR)为25 dB的条件下,ASQ算法可在保持原始密钥提取率(OKER)为0.86的同时,将密钥不一致率(KDR)降低至3.8×10^(-5);在无损量化的条件下,BMMQ算法可以把KDR降低至7×10^(-3)。最终生成的共享密钥序列通过了NIST(National Institute of Standards and Technology)随机性测试,验证了密钥的安全性和有效性。
