Simultaneous Quantification of Ibuprofen and Paracetamol in Tablet Formulations Using Transmission Fourier Transform Infrared Spectroscopy

A very simple, non-destructive, inexpensive and green strategy was applied for the simultaneous determination of ibu-profen (IBP) and paracetamol (PC) using transmission Fourier Transform Infrared (FTIR) spectroscopy in tablet formulations for routine quality control laboratories. For the determination of the active pharmaceutical ingredients (API), KBr pellets containing known amount of standards and samples were used for acquisition of the FTIR spectra. The partial least squares (PLS) calibration model was developed using the spectral region from 1781 - 1683 cm-1 for IBP and 1630 - 1530 cm-1 for PC. The excellent coefficients of determination (R2), 0.9999 and 0.9998 were achieved for IBP and PC, respectively. The accuracy of calibration model was also verified through root mean square error of cross validation (RMSECV) which was found to be 0.064. This work clearly shows the capability of transmission FTIR spectroscopy for assessment of exact quantity of API to control the quality of finished products as well as during processing in pharmaceutical industries without involvement of any solvent.

Secure Transmission Scheme Based on Dual-Thresholds for Simultaneous Wireless Information and Power Transfer

This paper studies a simultaneous wireless information and power transfer system with multiple external eavesdroppers and internal curious users.We model the random network by Poisson cluster process in consideration of the case where eavesdroppers hide around certain targets.Focusing on the users that work in harvesting-transmitting mode with time switching receivers,we establish communication model via time division multiple access.On this basis,we propose a lightweight secure transmission scheme based on dual-thresholds for physical-layer security enhancement,which consists of two protocols applied to the downlink(DL) and uplink(UL) transmission respectively.In the DL,we design a dynamic information-power switching transmission protocol based on signal-to-noise ratio threshold,which provides an opportunistic approach to reform the fixed period allocation of information and power transfer;in the UL,an energy threshold is proposed for users to control the transmission,which is called a user-led on-off transmission protocol.Furthermore,we give a comprehensive performance analysis for the proposed scheme in terms of delay,reliability,security and secrecy throughput.Based on the analysis results,we optimize the two thresholds and the DL-UL allocationcoefficient to maximize the secrecy throughput.Simulation results show the proposed scheme can bring about a substantial secrecy gain.

Simultaneous transmission of time-frequency and data with co-amplification over urban fiber links

We demonstrate a simultaneous transmission of time-frequency and data over a 160-km urban business network in Shanghai.The signals are transmitted through a cascaded optical link consisting of 48 km and 32 km,which are connected by an optical relay.The metrological signals are inserted into the communication network using dense wavelength division multiplexing.The influence of the interference between different signals has been discussed.The experimental results demonstrate that the radio frequency(RF)instability can reach 2.1×10^(-14)at 1 s and 2.3×10^(-17)at 10,000 s,and the time interval transfer of one pulse per second(1 PPS)signal with less than 10 ps at 1 s is obtained.This work paves the way for the widespread dissemination of ultra-stable time and frequency signals over the communication networks.

Recent developments in HVDC transmission systems to support renewable energy integration

The demands for massive renewable energy integration, passive network power supply, and global energy interconnection have all gradually increased, posing new challenges for high voltage direct current(HVDC) power transmission systems, including more complex topology and increased diversity of bipolar HVDC transmission. This study proposes that these two factors have led to new requirements for HVDC control strategies. Moreover, due to the diverse applications of HVDC transmission technology, each station in the system has different requirements. Furthermore, the topology of the AC-DC converter is being continuously developed, revealing a trend towards hybrid converter stations.

In-package P/G planes analysis and optimization based on transmission matrix method

Power integrity (PI) has become a limiting factor for the chip's overall performance, and how to place in-package decoupling capacitors to improve a chip's PI performance has become a hot issue. In this paper, we propose an improved trans- mission matrix method (TMM) for fast decoupling capacitance allocation. An irregular grid partition mechanism is proposed, which helps speed up the impedance computation and complies better with the irregular power/ground (P/G) plane or planes with many vias and decoupling capacitors. Furthermore, we also ameliorate the computation procedure of the impedance matrix whenever decoupling capacitors are inserted or removed at specific ports. With the fast computation of impedance change, in-package decoupling capacitor allocation is done with an efficient change based method in the frequency domain. Experimental results show that our approach can gain about 5× speedup compared with a general TMM, and is efficient in restraining the noise on the P/G plane.

基于谐波通讯的无线电能与反向信号同步传输技术

针对现有无线电能与反向信号同步传输(simultaneous wireless power and reverse signal transmission,SWPRST)系统存在较大无功功率、负载电压易受信号传输发生波动或需要额外增加高频信号源等问题,提出一种基于谐波通讯的SWPRST技术,通过利用逆变器输出方波电压中的基波分量传输电能,三次谐波分量传输信号。不需要外加高频信号发射电路,实现了可靠的电能与反向信号同步传输。首先,给出基于谐波通讯的SWPRST系统结构,对其工作模式和基本原理进行分析;接着,建立系统等效数学模型,分析系统参数取值对信号与电能传输之间的互扰影响;然后,对信号的调制解调电路进行设计,分析信号检测通道参数对信号传输速率的影响;最后,搭建实验平台对理论分析进行验证,实验结果表明,该方法在有效实现了无线电能与反向信号同步传输的同时,信号无误码率传输速率可达5 kbps,同时系统具有无功小,输出负载电压几乎无波动(电压波动率0.33%)等优点。该方法采用谐波作为信号载体,为多频利用式实现电能与反向信号同步传输系统提供一种新的思路,具有较好的理论意义与实际工程应用价值。

超声波无线电能传输的声电通道设计

为了解决磁耦合方式无线电能传输技术在金属障碍环境下因涡流效应而效率低下问题,该文开展了金属障碍环境下超声无线电能传输技术研究。首先从声学的角度分析能量传输通道参数对声波透射系数的影响规律,并指导完成通道参数的配置。然后,采用同时共轭阻抗匹配技术完成通道输入端口与输出端口的阻抗匹配网络设计,并通过实验验证阻抗匹配网络的有效性。测试结果表明,该文所设计的超声波无线电能传输系统透11 mm厚304不锈钢障碍的理论最佳传输效率为68%,进行同时共轭阻抗匹配后通道的实际能量传输效率为56.25%,传输功率达51.53 W。该研究所达到的能量传输效率和传输功率均能满足绝大部分使用需求。该技术在军事、航天等领域具有较好的应用前景。

面向无线传能的磁耦合通信射频链路解耦设计

针对磁耦合无线能量数据协同传输中传能链路与通信链路的解耦需求,在采用DD型通信线圈与传能线圈实现空域解耦的基础上,开展了滤波网络与线圈的协同设计,提升了通信链路通带阻抗匹配特性和带外抑制能力,并进一步引入带阻滤波网络,增强了与传能线圈的频域解耦。在耦合距离为30 mm时,搭建了与167 kHz无线传能天线共口径的磁耦合通信天线与滤波馈电网络硬件,在中心频率14.8 MHz实现了4 MHz的-3 dB通带带宽,该解耦天线系统相比DD线圈天线对传能信号提高了85 dB的抑制能力。

用于VSLAM系统的CNN在FPGA平台上的加速

为实现视觉同步定位与建图系统中卷积神经网络在FPGA上的加速,基于SuperPoint模型设计一种低功耗高效CNN加速器及相应的SoC系统。采用循环分块、数据复用、计算单元展开和双缓冲策略充分利用加速器的片上资源;为提高突发传输效率,预先对权重参数重排;提出Pack模块和Unpack模块,设计多通道数据传输,用于提高传输带宽。在Ultra96-V2 FPGA平台上部署整个SoC系统,在仅3 W左右的功耗下实现25.63 GOPS的吞吐量,其BRAM效率、DSP效率、性能密度和功耗效率相比之前的文献有明显优势。

深海无线传能技术的发展与展望

深海无线传能技术具有安全、可靠、隐蔽、灵活等特点,可以大大提升水下无人装备的续航能力,支撑其连续、隐蔽作业。本文综述了水下无线传能技术的发展现状,分析了复杂海洋环境对无线传能传输效率、稳定性、低噪声、电磁兼容性、境耐压防腐的影响,综合判断水下无线传能的发展趋势,提炼出水下无线传能的关键技术方向,以期水下无线传能技术为我国海洋装备的发展奠定基础。

基于STARS的安全认知无线电联合波束成形优化算法

基于可重构智能表面(RIS,reconfigurable intelligent surface)的安全认知无线电(SCR,secure cognitive radio)系统均假设次用户(SU,secondary user)和主用户(PU,primary user)在基站(BS,base station)的同一侧,仅能够实现通信区域的部分覆盖,限制了RIS部署的灵活性和有效性。为了解决上述问题,提出了一种新的基于同时透射和反射表面(STARS,simultaneously transmitting and reflecting surface)的SCR系统。在该系统中,STARS能够实现通信区域的全覆盖,利用透射波束成形向量提高SU的接收信号强度,同时利用反射波束成形向量降低SU对PU的干扰,为SCR系统的设计提供了新的优化自由度(DoF,degree of freedom)。考虑SU保密率约束、PU干扰功率约束(IPC,interference power constraint)和STARS透射/反射参数约束,从降低系统总功耗角度出发,以最小化BS发射功率为目标,构建BS主动波束成形向量和STARS透射/反射波束成形向量联合优化问题。这一最小化问题是变量耦合非凸问题,很难直接求解,提出了基于凸差松弛(DCR,difference-of-convex relaxation)方法和顺序秩一约束松弛(SROCR,sequential rank-one constraint relaxation)方法的交替优化(AO,alternating optimization)算法,联合设计BS主动波束成形向量和STARS透射/反射波束成形向量。仿真结果表明,所提算法具有良好的收敛性能,能够有效降低SU对PU的干扰,且与传统RIS、随机相位、最大比传输(MRT,maximum-ratio transmission)和等能量分裂(Equal ES,equal energy splitting)方案相比,BS发射功率分别降低了8.3%、15.4%、5.9%和5.3%。

基于共享通道的双向无线电能和信息同时传输系统特性研究

随着电力电子技术、控制技术及开关电源相关技术的发展,电能和信号传输逐渐从以电缆为传输媒介的传统传输方式逐渐向无线传输方向发展。对于需要在水介质中长时间工作的电气设备而言,能量供应是维持其正常工作的关键因素,但由于电缆进行物理连接的传统传输方式在水介质中运用较为不便,并且存在较大的安全隐患,因此需要构建一个基于共享通道的双向无线电能和信息同时传输的系统。

基于换相角预测计算的高压直流输电双桥共同换相预判方法

高压直流输电系统交流故障下出现双桥共同换相会增大换相失败的风险,提前判断双桥共同换相的发生有利于及时采取措施避免换相失败。为获取对双桥共同换相进行预判所需的高精度换相角预测计算结果,利用拉格朗日中值定理建立换相角与中值时刻的关系,并构造虚拟换相过程用于确定中值时刻。仿真结果表明,所提换相角预测计算方法具有良好的鲁棒性和精度,用于双桥共同换相预判中能有效预判双桥共同换相的发生。

虚拟多输入多输出无线电能与信息同步传输技术

在无线通信系统中,多输入多输出(MIMO)天线技术可有效提高信号传输速率和信道利用率。传统的能量调制式无线电能与信息同步传输(SWPIT)技术主要依赖单输入单输出线圈实现系统的供电和通信,难以实现多路并行通信。该文针对需要多信号接收器的无线供电场景,提出一种虚拟MIMO-SWPIT技术以满足多端通信的需求。所提系统可在两种状态下工作:当仅需无线供电时,系统工作在谐振状态进行高效电能传输;当需要通信时,通过控制逆变器开关信号的相移角和频率,在发射线圈中构造非标准正弦多载波(即虚拟多输入),以其中的基波和谐波分量作为通信载波传输信息。系统接收回路对基波和谐波所携带的信息进行解调(即虚拟多输出),同时谐波分量可用于负载供电。搭建的实验样机实现了稳定的电能与双通道信息并行同步传输,通信时电压波动低于3%,每路通道信息传输速率为4.0 kbit/s,验证了所提方案的可行性。

大功率高速激光无线能量信息同传技术

激光通信及激光能量传输技术都以激光为载体,进行空间传输,将能量和携带信息传递给远端设备,在系统构成上具有天然共同点,因此,在同一套系统内实现激光通信/传能两种功能,必将成为未来系统能源信息传输的有效手段,将优化系统构成,提高系统效率。文章研究了激光无线能量信息同传技术,对激光能量信息同传机制、同传机制下激光信号调制解调、高效率光电转换技术,提出高效能量信息同传系统设计方案,研制了火箭地面激光传能通信一体化样机,实现25 m传输距离,激光无线供电461W,激光无线通信速率500Mbps,为下一步高效激光无线能量信息同传系统发展提供解决思路。

中国居民家庭“收入-健康”循环效应代际传递的经验验证

健康是增加收入、提高代际收入流动性的重要途径。本文基于2010—2020年中国家庭追踪调查(CFPS)数据,采用3SLS法构建联立方程组估计健康与收入间的相互关系和循环效应,并进一步通过Blanden法对健康在代际收入传递中的贡献率进行分解和测度。结果表明:健康与收入之间呈现相互作用的双向因果关系,即“收入—健康”具有循环效应。我国存在代际收入固化现象,健康人力资本对子代收入的提升具有促进作用,进一步对健康贡献率进行异质性分析可知,农村、母亲、低收入阶层、子代16~25岁和初中阶段的健康贡献率更大。因此,应构建阻隔代际收入固化的循环传递效应机制,重视健康人力资本在打破收入固化中的积极作用,完善公共卫生和健康政策以提高居民健康水平,增强代际流动性。

面向航天器地面测试的双参量同步采集与无线传输系统设计

针对航天器地面测试过程中双参量同步采集与数据无线传输的需求,提出了一种双参量同步采集与无线传输系统。设计了基于FPGA的双过载参量同步采样电路,搭建了长距离LoRa和高速率GFSK调制动态切换的无线传输模式,实现了过载加速度和压力参量的同步、实时无线传输。为增强系统可靠性,设计了Flash存储模式,在无线传输出现故障时通过有线通信读取数据。测试表明,输入信号频率在4 kHz内,可实现双通道同步采集与无线传输,且波形可复现。采用GFSK无线传输,速率可达2 Mbps,传输距离为0.5 km;采用LoRa无线传输,速率为1 kbps时可实现1.2 km的远距离无线传输。该系统能够满足过载向心加速度和压力的同步、远距离、实时采集与监测,在航天器地面测试领域应用潜力巨大。

无线传能磁通信带内干扰抑制射频架构与算法

针对磁耦合无线电能与数据协同传输系统中磁耦合数据通信面临的传能装置谐波干扰,建立了基于DD线圈的通信和干扰感测相互隔离的射频通道,并在数字域采用基于递归最小二乘(Recursive Least Square,RLS)算法的数字干扰对消,抑制通信链路的残余传能干扰。通过仿真验证了方案的可行性。建立了中心频率17.6 MHz、通信带宽2 MHz的通信与干扰感测通道,并基于GNU Radio和X310软件无线电平台完成了算法验证,成功恢复出受传能谐波干扰的正交相移键控(Phase-Shift Keying,QPSK)通信信号星座图,将带内干扰谐波抑制了12 dB以上,提升了磁耦合通信链路抗干扰能力。

Stability Control Method for Hybrid AC-DC Transmission Systems Considering Cross-region Multi-energy Coordination

China has built the largest hybrid AC-DC power systems with the highest voltage levels in the world.How to effectively guarantee the stable operation of the hybrid AC-DC power systems is a critical undertaking and technical demand.In view of the stability problems of hybrid AC-DC transmission systems with a high percentage of wind power,a hybrid AC・DC transmission system's stability control method that considers cross-region multi-energy coordination is established in this paper.Aiming at the uncertainty of a high percentage of wind power,the dynamic inversion method is used as the inner loop for robust control,and the battery energy storage and regenerative electric boiler are used as multiple energy sources to coordinate,and the outer loop robust control is used for uncertainty compensation.The hybrid AC-DC weak-sending terminal system with wind power is analyzed and designed by//-synthesis based on the Hg control,and a stability control method for hybrid AC-DC transmission systems,considering cross-region multi-energy coordination,is established.Simulation results show that the model proposed in this paper can guarantee the robustness of the dynamic inversion method and improves the control performance of AC-DC transmission systems.

Simultaneously transmitting and reflecting(STAR)RISs for 6G:fundamentals,recent advances,and future directions

Simultaneously transmitting and reflecting reconfigurable intelligent surfaces(STAR-RISs)have been attracting significant attention in both academia and industry for their advantages of achieving 360°coverage and enhanced degrees-of-freedom.This article first identifies the fundamentals of STAR-RIS,by discussing the hardware models,channel models,and signal models.Then,three representative categorizing approaches for STAR-RISs are introduced from the phase-shift,directional,and energy consumption perspectives.Furthermore,the beamforming design of STAR-RISs is investigated for both independent and coupled phase-shift cases.As a recent advance,a general optimization framework,which has high compatibility and provable optimality regardless of the application scenarios,is proposed.As a further advance,several promising applications are discussed to demonstrate the potential benefits of applying STAR-RISs in sixth-generation wireless communication.Lastly,a few future directions and research opportunities are highlighted.