A novel multi-channel porous structure facilitating mass transport towards highly efficient alkaline water electrolysis

An advantageous porous architecture of electrodes is pivotal in significantly enhancing alkaline water electrolysis(AWE)efficiency by optimizing the mass transport mechanisms.This effect becomes even more pronounced when aiming to achieve elevated current densities.Herein,we employed a rapid and scalable laser texturing process to craft novel multi-channel porous electrodes.Particularly,the obtained electrodes exhibit the lowest Tafel slope of 79 mV dec^(-1)(HER)and 49 mV dec^(-1)(OER).As anticipated,the alkaline electrolyzer(AEL)cell incorporating multi-channel porous electrodes(NP-LT30)exhibited a remarkable improvement in cell efficiency,with voltage drops(from 2.28 to 1.97 V)exceeding 300 mV under 1 A cm^(-1),compared to conventional perforated Ni plate electrodes.This enhancement mainly stemmed from the employed multi-channel porous structure,facilitating mass transport and bubble dynamics through an innovative convection mode,surpassing the traditional convection mode.Furthermore,the NP-LT30-based AEL cell demonstrated exceptional durability for 300 h under 1.0 A cm^(-2).This study underscores the capability of the novel multi-channel porous electrodes to expedite mass transport in practical AWE applications.

Design of Cold-Junction Compensation and Disconnection Detection Circuits of Various Thermocouples and Implementation of Multi-Channel Interfaces Using Them-A Secondary Publication

Cold-junction compensation(CJC)and disconnection detection circuit design of various thermocouples(TC)and multi-channel TC interface circuits were designed.The CJC and disconnection detection circuit consists of a CJC semiconductor device,an instrumentation amplifier(IA),two resistors,and a diode for disconnection detection.Based on the basic circuit,a multi-channel interface circuit was also implemented.The CJC was implemented using compensation semiconductor and IA,and disconnection detection was detected by using two resistors and a diode so that IA input voltage became-0.42 V.As a result of the experiment using R-type TC,the error of the designed circuit was reduced from 0.14 mV to 3μV after CJC in the temperature range of 0°C to 1400°C.In addition,it was confirmed that the output voltage of IA was saturated from 88 mV to-14.2 V when TC was disconnected from normal.The output voltage of the designed circuit was 0 V to 10 V in the temperature range of 0°C to 1400°C.The results of the 4-channel interface experiment using R-type TC were almost identical to the CJC and disconnection detection results for each channel.The implemented multi-channel interface has a feature that can be applied equally to E,J,K,T,R,and S-type TCs by changing the terminals of CJC semiconductor devices and adjusting the IA gain.

Multi-channel terahertz focused beam generator based on shared-aperture metasurface

Most of existing metasurfaces usually have limited channel behavior,which seriouslyhinders their development and application.In this paper,we propose a multi-channel terahertz focused beam generator based on shared-aperture metasurface,and the generator consists of a top square metal strip,a middle layer of silica and a metal bottom plate.By changing the position and size of the shared-aperture array,the designed metasurface can generate any number of multi-channel focusing beams at different predicted positions.In addition,the energy intensity of focusing beams can be controlled.The full-wave simulation results show that the metasurface achieves four-channel vortex focused beam generation with different topological charges,and five-,six-,eight-channel focused beam generation with different energy intensities at a frequency of 1 THz,which are in good agreement with the theoretically calculated predictions.This work can provide a new idea for designing the terahertz multichannel devices.

Fast pre-stack multi-channel inversion constrained by seismic reflection features

Classical multi-channel technology can significantly reduce the pre-stack seismic inversion uncertainty, especially for complex geology such as high dipping structures. However, due to the consideration of complex structure or reflection features, the existing multi-channel inversion methods have to adopt the highly time-consuming strategy of arranging seismic data trace-by-trace, limiting its wide application in pre-stack inversion. A fast pre-stack multi-channel inversion constrained by seismic reflection features has been proposed to address this issue. The key to our method is to re-characterize the reflection features to directly constrain the pre-stack inversion through a Hadamard product operator without rearranging the seismic data. The seismic reflection features can reflect the distribution of the stratum reflection interface, and we obtained them from the post-stack profile by searching the shortest local Euclidean distance between adjacent seismic traces. Instead of directly constructing a large-size reflection features constraint operator advocated by the conventional methods, through decomposing the reflection features along the vertical and horizontal direction at a particular sampling point, we have constructed a computationally well-behaved constraint operator represented by the vertical and horizontal partial derivatives. Based on the Alternating Direction Method of Multipliers (ADMM) optimization, we have derived a fast algorithm for solving the objective function, including Hadamard product operators. Compared with the conventional reflection features constrained inversion, the proposed method is more efficient and accurate, proved on the Overthrust model and a field data set.

Opportunistic Routing with Multi-Channel Cooperative Neighbour Discovery

Due to the scattered nature of the network,data transmission in a dis-tributed Mobile Ad-hoc Network(MANET)consumes more energy resources(ER)than in a centralized network,resulting in a shorter network lifespan(NL).As a result,we build an Enhanced Opportunistic Routing(EORP)protocol architecture in order to address the issues raised before.This proposed routing protocol goal is to manage the routing cost by employing power,load,and delay to manage the routing energy consumption based on theflooding of control pack-ets from the target node.According to the goal of the proposed protocol techni-que,it is possible to manage the routing cost by applying power,load,and delay.The proposed technique also manage the routing energy consumption based on theflooding of control packets from the destination node in order to reduce the routing cost.Control packet exchange between the target and all the nodes,on the other hand,is capable of having an influence on the overall efficiency of the system.The EORP protocol and the Multi-channel Cooperative Neighbour Discovery(MCCND)protocol have been designed to detect the cooperative adja-cent nodes for each node in the routing route as part of the routing path discovery process,which occurs during control packet transmission.While control packet transmission is taking place during the routing path discovery process,the EORP protocol and the Multi-channel Cooperative Neighbour Discovery(MCCND)protocol have been designed to detect the cooperative adjacent nodes for each node in the routing.Also included is a simulation of these protocols in order to evaluate their performance across a wide range of packet speeds using Constant Bit Rate(CBR).When the packet rate of the CBR is 20 packets per second,the results reveal that the EORP-MCCND is 0.6 s quicker than the state-of-the-art protocols,according to thefindings.Assuming that the CBR packet rate is 20 packets per second,the EORP-MCCND achieves 0.6 s of End 2 End Delay,0.05 s of Routing Overhead Delay,120 s of Network Lifetime,and 20 J of Energy Consumption efficiency,which is much better than that of the state-of-the-art protocols.

基于Modelica的并联多通道系统流动不稳定性仿真研究

在核反应堆堆芯并联通道中,流动不稳定性会导致临界热流密度(CHF)明显下降或使堆芯燃料组件产生机械振荡,从而危及反应堆正常运行。为了解决该问题,在参考某高温高压汽水两相热工水力实验装置的基础上,基于NUMAP软件搭建了并联双通道系统模型进行流动不稳定性仿真研究。实验表明,当并联通道数分别为2、3、4时,通过仿真计算相同工况条件下并联多通道系统流动不稳定性边界,流动不稳定性边界计算误差不超过±5%,验证了存在多个并联加热通道时采用并联双通道结构即可获得其流动不稳定边界,证实了该软件对流动不稳定性现象的瞬态分析能力。

Parametric study on contact sensors for MASW measurement-based interfacial debonding detection for SCCS

Steel-concrete composite structures(SCCS)have been widely used as primary load-bearing components in large-scale civil infrastructures.As the basis of the co-working ability of steel plate and concrete,the bonding status plays an essential role in guaranteeing the structural performance of SCCS.Accordingly,efficient non-destructive testing(NDT)on interfacial debondings in SCCS has become a prominent research area.Multi-channel analysis of surface waves(MASW)has been validated as an effective NDT technique for interfacial debonding detection for SCCS.However,the feasibility of MASW must be validated using experimental measurements.This study establishes a high-frequency data synchronous acquisition system with 32 channels to perform comparative verification experiments in depth.First,the current sensing approaches for high-frequency vibration and stress waves are summarized.Secondly,three types of contact sensors,namely,piezoelectric lead-zirconate-titanate(PZT)patches,accelerometers,and ultrasonic transducers,are selected for MASW measurement.Then,the selection and optimization of the force hammer head are performed.Comparative experiments are carried out for the optimal selection of ultrasonic transducers,PZT patches,and accelerometers for MASW measurement.In addition,the influence of different pasting methods on the output signal of the sensor array is discussed.Experimental results indicate that optimized PZT patches,acceleration sensors,and ultrasonic transducers can provide efficient data acquisition for MASW-based non-destructive experiments.The research findings in this study lay a solid foundation for analyzing the recognition accuracy of contact MASW measurement using different sensor arrays.

基于Multi-Radio Multi-Channel传感器网络无冲突信道分配算法的研究

为降低通信冲突和信道干扰,对Mult-i Radio Mult-i Channel传感器网络无冲突信道进行研究,结果证实在网络通信半径大于3倍的网络最大功率通信半径的前提下,Sensor节点规模满足2倍网络功率级数加1的环境下,网络无冲突信道分配的信道数达到网络信道冲突图的最大值。文章通过对无冲突信道算法的运用,最终证实其可以有效地提高传感器网络的工作效率,大幅度提升网络的吞吐量。

一种PT100多通道测温系统设计及实现

本文阐述了一种基于国产ARM芯片方案的三线制PT100高精度多通道测温系统的设计与实现。该系统采用国产ARM处理器和24位的高精度delta-sigma A/D转换器,使用恒压源与精密电阻对各通道PT100进行分压,再通过差分放大电路放大后进行采样,实现多路温度的准确测量。并且通过硬件电路设计与软件数据处理算法设计,有效地解决了接线电阻与自热效应对测温精度的影响。通过实物测试结果显示,该系统表现出性能稳定、体积小巧的特点,其测量精度可达0.5 ℃。

Discussion on the Status Quo of Vocational College Students’Self-Image and its Improvement Strategies

An individual’s self-image is a multi-dimensional and multi-structural concept.Its internal dimensions include ability,knowledge,values,personality,and temperament,and its external dimensions are physical appearance,behavior,and clothing.A good image will have a positive impact both in life and at work.We will choose appropriate clothing and makeup to modify the external image and cultivate positive qualities such as correct values and an optimistic attitude towards life to enhance internal dimensions.Among them,“personality”and“ability”mostly belong to the research category of mental health education,and“values”fit in the research field of ideological and political education.Ideological and political education and mental health education are both important components of higher education,which show similarities between them.Ideological and political education and mental health education can complement each other in many ways to enhance students’self-image.

融合多头自注意力的AeroMACS自适应调制编码算法

航空移动机场通信系统(AeroMACS)因传输速率高、安全性好等优点成为机场、空地通信网络的重要组成部分。针对飞机起飞、着陆高速移动阶段的信道快速时变导致信道状态信息(CSI)过时和多普勒频移大等引起通信质量恶化的问题,利用多头自注意力机制,提出了基于Transformer神经网络的信道预测方法。根据实时预测的信噪比(SNR)来调整AeroMACS的WiMAX和5G双模的调制编码方案(MCS)。仿真结果表明,与其他3种人工智能方法相比,所提出的基于Transformer网络的信道预测方法能够达到较高的准确率,并提升了系统的总吞吐量,对缓解信道参数过时现状和提高系统通信性能具有良好的促进作用。

多路绝对激光测距仪精密三维控制网的建立与解算

建立高精度三维控制网是实现大型粒子加速器等精密工程测量的前提条件,目前主要通过间接测量两点间距离或者自由设站实现,而多路绝对激光测距仪可在0.02~30 m范围内直接测量空间中两点间距离,利用高精度绝对测距值可建立高精度的三维测边控制网。基于多路绝对激光测距仪高精度绝对测距性能,建立仅含控制点间距离的秩亏自由网平差模型,通过任意初值选取,应用改进的LM算法迭代求解非线性超定方程组实现坐标概算,得到方程组的一组解作为未知数的近似值进行整网平差,获得高精度控制点坐标。实验数据分析表明,在8 m×3.5 m×2.5 m的实验范围内,建立控制点平均点位精度优于±1.14μm的三维测边网,可满足现代工业生产中对安装定位的高精度需求。

多信道光纤通信系统信号偏差控制方法研究

光纤通信系统多信道的开发在分担了并发用户通信请求压力的同时,也使得信号偏差问题越来越严重,导致通信可靠性下降,通信延迟问题加重。针对上述问题,研究一种多信道光纤通信系统信号偏差控制方法。利用采集器获取同一时段通信系统信道信号与导频信道信号并实施滤波处理,计算两种信号之间的相似度,检测是否存在信号偏差。利用零点比较法计算两种信号之间的相位差。通过纠正比例因子的引入和粒子群算法的整定,优化PID信号偏差控制器,以相位差为输入,得出多信道光纤通信系统信号偏差控制量。结果表明:与控制前相比,控制后三信道通信信号与导频信道信号之间的相似度更大,而且均大于0.95,由此说明所研究控制方法是有效的,抑制了信号偏差现象。

氯乙烯转化器温度采集和检测系统的优化改造

针对氯乙烯合成转化器温度采集和检测系统信号不稳定、数据传输延迟的问题,进行了技术改进。使用MTL831B多路温度转换器采集温度,并对DCS进行优化,有效解决了上述问题,温度显示率和准确率均达到100%。

基于单片机的多通道电路检测系统设计

针对电压、电流检测技术中检测系统可检测通道不足的问题,提出并设计一种基于单片机的电路检测系统。该系统由采集电路、通道切换电路、放大与滤波电路、模/数转换电路、主控单片机以及显示器等部件组成。首先介绍了检测系统的主要技术,包括多通道检测及其相关的通道选通技术、电信号类型判别方法。其次从总体结构上介绍了检测系统,并对其中的放大与滤波电路、模/数转换电路数据处理等关键组成进行详细说明。最后根据多通道检测技术分析和系统设计,得出电路检测系统研究的相关结论。实际问题研究表明,所设计的电路检测系统具有较高的实际应用价值和进一步研究的价值。

基于嵌入式技术的液体泄露检测系统研究

液体管道在地下土壤环境中容易受到腐蚀,这会影响管道的使用寿命和使用安全,为此通过多个液体检测传感器、油位传感器、温度传感器等硬件设备研究液体管道的性能检测。基于嵌入式技术实现检测的硬件和软件设计,其中硬件包括中央处理器、存储器、计算器、控制器、A/D转换模块、D/A转换模块和多路传感器接口等关键部件,实现数据信息的采集、计算与检测。中央处理器以S3C6410的内核为微处理器(ARM11)的处理器,通过串行外围设备接口(SPI)总线传递到嵌入式软件中的Linux内核空间。通过伯努利方程实现数据信息的故障判断。实验表明,本研究对液体管道检测的精度最高,对接精密度高达99.2%,提高了检测的工作效率。

A Novel Design of Efficient Multi-channel UART Controller Based on FPGA

In traditional universal asynchronous receiver transmitter （UART） controller, the data transmission is inefficient and the data bus utilization ratio is low. A novel design is provided to solve these problems. The architecture of the system is introduced, the flow charts of data processing as well as the implementation state machine are also presented in detail. This paper is concluded by comparing the performance of this design, which is realized on field programmable gate army （FPGA） using Verilog hardware description language （HDL）, with other traditional UART controllers.

Performance analysis of multi-channel order statistics detector for range-spread target

The problem of two order statistics detection schemes for the detection of a spatially distributed target in white Gaussian noise are studied.When the number of strong scattering cells is known,we first show an optimal detector,which requires many processing channels.The structure of such optimal detector is complex.Therefore,a simpler quasi-optimal detector is then introduced.The quasi-optimal detector,called the strong scattering cells’ number dependent order statistics（SND-OS） detector,takes the form of an average of maximum strong scattering cells with a known number.If the number of strong scattering cells is unknown in real situation,the multi-channel order statistics（MC-OS） detector is used.In each channel,a various number of maximums scattered from target are averaged.Then,the false alarm probability analysis and thresholds sets for each channel are given,following the detection results presented by means of Monte Carlo simulation strategy based on simulated target model and three measured targets.In particular,the theoretical analysis and simulation results highlight that the MC-OS detector can efficiently detect range-spread targets in white Gaussian noise.

信道衰落下多智能体系统有限时间一致性控制

针对带有信道衰落下二阶多智能体系统的有限时间一致性跟踪问题,文中提出了基于滑模策略的分布式控制算法。根据智能体的拓扑结构搭建数学模型构造了随机信道衰落影响下的一致性误差函数,基于误差函数设计一致性协议将系统的一致性问题转化为跟踪误差系统的稳定性问题。设计了指数型非奇异终端滑模面,结合Lyapunov稳定性理论和滑模控制理论分析了误差系统的有限时间稳定性和滑模可达性。采用1个领导者和4个跟随者的多智能体模型进行仿真实验,结果显示4个跟随者可以准确跟踪领导者,达成系统跟踪一致性,且在10 s时其误差函数曲线也趋于0,证明了控制策略的有效性。

A time-sharing multi-channel pulse amplitude analyzer

A conventional multi-channel pulse amplitude analyzer acquires single energy spectrum,but provides no information on its tendency with time.To address the limitation,we propose a scheme of time-sharing multichannel pulse amplitude analyzer(TSMCA).A dual-port random access memory is divided into two storage spaces,one for current energy spectrum data acquisition and another for previous energy spectrum data storage.The two tasks can be performed simultaneously,and the time-related variation tendency of energy spectrum can be obtained.A prototype system of TSMCA is designed.It performs nicely,with maximum channel number of 4096 in capacity of 2^(32)/Ch,minimal time-sharing slice of 25 ms,the differential nonlinearity of <1.5%,and the integral nonlinearity of <0.3%.