Fiber cladding dual channel surface plasmon resonance sensor based on S-type fiber

Fiber cladding surface plasmon resonance(SPR)sensors have few structures,and a clad SPR sensor based on S-type fiber is proposed in this paper.This new type of fiber cladding SPR sensor was formed by electrofusing an S-shaped structure on the fiber to couple the light in the fiber core to the cladding.In this paper,the effects of fiber parameters on the performance of the sensor were studied by simulation and experiment.Based on the conclusion that the smaller the core diameter is,the closer the working band of the SPR resonance is to long wavelengths,and that the geometric characteristics mean that a multimode fiber can receive the fiber cladding light from a small core diameter few-mode fiber,a dual channel SPR sensor with a double S-type fiber cascade was proposed.In the refractive index detection range of 1.333–1.385refractive index units(RIU),the resonant working band of channel I is 627.66 nm–759.78 nm,with an average sensitivity of 2540.77 nm/RIU,and the resonant working band of channel II is 518.24 nm–658.2 nm,with an average sensitivity of2691.54 nm/RIU.The processing method for the S-type fiber cladding SPR sensor is simple,effectively solving the problem of this type of SPR sensor structure and the difficult realization of a dual channel.The sensor is expected to be used in the fields of medical treatment and biological analysis.

Cascaded dual-channel fiber SPR temperature sensor based on liquid and solid encapsulations

In order to control the working wavelength range of the fiber surface plasmon resonance(SPR)temperature sensor and realize the wavelength division multiplexing type multi-channel fiber SPR temperature sensor,by comprehensively investigating the influence of liquids with different thermal-optical coefficients and solid packaging materials on the performance of fiber SPR temperature sensor,a dual-channel fiber SPR temperature sensor based on liquid-solid cascade encapsulation was designed and fabricated.The liquid temperature sensing stage encapsulated in capillary worked in 616.03 nm-639.05 nm band,the solid sensing stage coated with pouring sealant worked in 719.37 nm-825.27 nm band,and the two stages were cascaded to form a fiber dual-channel temperature sensor.The testing results indicated that when the temperature range was 35℃-95℃,the sensitivity of two-stage temperature detection was−0.384 nm/℃and−1.765 nm/℃respectively.The proposed fiber sensor has simple fabrication and excellent performance which can be widely used in various fields of dual-channel temperature measurement and temperature compensation.

A Novel Design of Fuzzy PID Controllers for Dual-Sensor Cardiac Pacemaker Systems

This work proposes to design a fuzzy proportional-integral derivative (FPID) controller for dual-sensor cardiac pacemaker systems, which can automatically control the heart rate to accurately track a desired preset profile. The combination of fuzzy logic and conventional PID control approaches is adopted for the controller design based on dual-sensors. This controller offers good adaptation of the heart rate to the physiological needs of the patient under different states (rest and walk). Through comparing with the conventional fuzzy control algorithm, FPID provides a more suitable control strategy to determine a pacing rate in order to achieve a closer match between actual heart rate and a desired profile. To assist the heartbeat recovery, the stimuli with adjustable pacing rate is generated by the pacemaker according to the FPID controller, such actual heart rate may track the preset heart rate faithfully. Simulation results confirm that this proposed control design is effective for heartbeat recovery and maintenance. This study will be helpful not only for the analysis and treatment of bradycardias but also for improving the performance of medical devices.

Axial Micro-Strain Sensor Based on FM-FBG via Dual-Mode ML-FMF in Sensor Networks

An in-fiber axial micro-strain sensor based on a Few Mode Fiber Bragg Grating (FM-FBG) is proposed and experimentally characterized. This FM-FBG is in inscribed in a multi-layer few-mode fiber (ML-FMF), and could acquire the change of the axial strain along fibers, which depends on the transmission dips. On account of the distinct dual-mode property, a good stability of this sensor is realized. The two transmission dips could have the different sensing behaviors. Both the propagation characteristics and operation principle of such a sensor are demonstrated in detail. High sensitivity of the FM-FBG, ~4 pm/με and ~4.5 pm/με within the range of 0 με - 1456 με, is experimentally achieved. FM-FBGs could be easily scattered along one fiber. So this sensor may have a great potential of being used in sensor networks.

Fuzzy Controller for Dual Sensors Cardiac Pacemaker System in Patients with Bradycardias at Rest

Cardiovascular disease is defined as a heart rate that is less than 60 bpm. Implantable cardiac devices such as pacemakers are widely used nowadays. In this paper, design and implementation of the heart model can be controlled to be the heart of a patient suffering from a decrease in heart rate (Bradycardia). A system is designed to sense and calculate the heart rate per minute and it is considered as an input to the controller. The design and implementation of Mamdani fuzzy controller to generate electric pulses that mimic the natural pacing system of the heart maintains an adequate heart rate by delivering controlled, rhythmic electrical stimuli to the chambers of the patient heart. The proposed controller is tested by using Matlab/Simulink program.

A Dual-Parameter Fusion Distributed Optical Fiber Sensor System for Oil and Gas Pipeline Monitoring

For oil and gas pipeline monitoring applications, this paper proposed a dual-parameter fusion distributed fiber optic sensor system that enables distributed temperature and distributed vibration measurements in a single fiber. Through the fiber-scattering spectrum time domain detection combined with coded pulse sequence and Raman scattering spectrum is obtained, which realizes high-resolution temperature measurement and wide-band vibrational wave measurement. The experimental results show that, on 10 km optical fiber measurement, temperature resolution up to 0.1?C and vibration response frequency range 20 Hz - 5 kHz. This sensing system achieves temperature and vibration dual-parameter measurements with fiber optics, greatly simplifying the system and facilitating installation and it can be widely used in oil and gas pipeline monitoring.

全局/滚动曝光兼容高动态抗辐照CMOS图像传感器设计

针对高速目标的高精度探测及辐射环境的应用要求,为解决全局与滚动曝光模式兼容难度大、灵敏度和动态低、帧速不高、抗辐照水平低等问题,对CMOS图像传感器架构、像素结构、列并行高精度数字化、高速读出、抗辐照加固等技术进行研究。基于单边列并行DDS、多模兼容的架构方案,设计了一款7.5μm×7.5μm,2048×2048可见光CMOS图像传感器,采用双增益像素结构、高帧速数字化读出、多通道可选输出、像素和电路抗辐照加固等方法,实现了全局与滚动曝光兼容、高灵敏度高动态成像、高精度数字化和高速输出、抗辐照加固等技术验证,填补了国内多模曝光兼容抗辐照CMOS图像传感技术研究空白。测试结果表明:器件功能正常,成像效果良好,动态范围、满阱电荷、灵敏度、帧速、抗辐照等指标满足预期要求,对高速高动态成像及辐射环境的系统应用具有重要意义。

早期香蕉枯萎病Foc4双探针核酸纸基检测传感器研制

为实现对早期香蕉枯萎病4号生理小种(fusarium oxysporum f.sp.cubense 4, Foc4)的准确检测,该研究提出一种基于胶体金的双探针纸基传感器。该传感器将2种不同粒径的胶体金分别与检测探针和信号增强探针结合,利用DNA探针代替抗原和抗体,形成双探针体系,通过增加信号增强探针降低检测限。基于目标序列与双探针体系的碱基互补配对形成“金标探针-目标序列-T线探针”复合物并在传感器的测试区被捕获,10 min内形成肉眼可见的目标产物,通过分析测试条带得到光强度峰面积并代入标准曲线中,实现Foc4定量检测。试验结果表明,双探针纸基传感器的检测限达到0.001 nmol/L,是传统纸基传感器的100倍,提高了检测灵敏度;在0.001~1 000.000 nmol/L范围内,Foc4浓度与测试线光强度峰面积呈线性关系;使用高浓度非互补探针进行试验干扰,发现非互补序列对检测效果基本无影响,表明该传感器具有较好的特异性;香蕉叶片Foc4检测的平均回收率为77.6%~102.3%,相对标准偏差为7.4%~7.7%。与传统形态学观察等检测方法相比,该研究提出的双探针核酸纸基检测传感器可以及时、快速、准确地判断早期Foc4的存在,具有良好的推广性和实际应用价值。

Active pixel image sensor array for dual vision using large-area bilayer WS_(2)

Transition metal dichalcogenides(TMDs)are a promising candidate for developing advanced sensors,particularly for day and night vision systems in vehicles,drones,and security surveillance.While traditional systems rely on separate sensors for different lighting conditions,TMDs can absorb light across a broad-spectrum range.In this study,a dual vision active pixel image sensor array based on bilayer WS2 phototransistors was implemented.The bilayer WS2 film was synthesized using a combined process of radio-frequency sputtering and chemical vapor deposition.The WS2-based thin-film transistors(TFTs)exhibit high average mobility,excellent Ion/Ioff,and uniform electrical properties.The optoelectronic properties of the TFTs array exhibited consistent behavior and can detect visible to near-infrared light with the highest responsivity of 1821 A W1(at a wavelength of 405 nm)owing to the photogating effect.Finally,red,green,blue,and near-infrared image sensing capabilities of active pixel image sensor array utilizing light stencil projection were demonstrated.The proposed image sensor array utilizing WS2 phototransistors has the potential to revolutionize the field of vision sensing,which could lead to a range of new opportunities in various applications,including night vision,pedestrian detection,various surveillance,and security systems.

双轴倾角传感器离轴倾斜测量的误差校正

二维摆动台常由离轴布局的两个一维摆动台组成。双轴倾角传感器用于二维摆动台倾斜测量时,难以避免出现传感器安装误差。同时,离轴布局的摆动台存在二维转轴间的角度耦合,即底层摆动台倾斜会造成上方摆动台的角度测量偏差。首先,对上述二维离轴倾斜系统的角度误差进行了分析和建模,将误差分类为近似线性误差和非线性误差。线性误差包括竖直和水平方向的倾角传感器安装误差。非线性误差则仅由摆动台离轴布局造成。随后,联合线性单应矩阵和非线性离轴倾角模型,提出了针对两类误差的校正方法,并制定了自动校正流程。最后,为了检验所提方法的校正精度,在±12°范围内进行了离轴角度调控实验。实验结果表明,二维摆动台倾斜角度测量精度由校正前的0.559°和-0.216°提高到了0.025°和0.013°,使角度误差减小了一个数量级。此外,为了进一步验证所提方法的有效性,与两种现有方法进行了对比实验。实验结果表明所提方法在校正精度和操作简易性方面均优于其他两种方法,证明了本文误差校正模型具有较高的完备性。

R6G-AAO双峰发射器的能量传递与Fe(III)/Cr(VI)的探测

设计了一种由罗丹明6G(Rhodamine 6G,R6G)和阳极氧化铝(anodised aluminium,AAO)组成的双发射固态探测器(R6G-AAO,RA),通过稳态/瞬态荧光光谱详细探究了R6G与AAO之间的能量传递过程。由于其具有双峰发射,因此,存在自校正效应,可以避免环境因素对探测结果的影响。此外,这种光致发光探测器能够用于检测金属Fe(III)和Cr(VI)两种离子。结果表明,当用RA对Fe(III)进行检测时,检出限较高且具有可重复使用性;用于Cr(VI)检测时,能量传递过程被破坏,其两个发射峰的变化比例不同,展现出了双峰探测器的自校正效应。还进一步阐述了探测器对Fe(III)和Cr(VI)的检测机制。

可用于运动监测的双模态离子传感纤维

针对传统刚性导电材料柔韧性差、舒适性低及现有离子导电材料多为薄膜或块状而导致透气透湿性差等问题,提出一种湿法纺丝一步制得的一维离子传感纤维,并研究其物理性能及传感性能,阐述其未来的发展潜力。测试结果表明,离子传感纤维灵敏度高(规格因子GF=201)且可准确监测微小应变(~05%),具有宽应变监测范围;响应时间小于50 ms,与人体皮肤的响应时间接近,足以监测人体运动信号;表现出优异的循环耐久性,10000次循环拉伸后仍能保持电阻信号变化稳定;同时具有湿度传感性能,对环境中湿度的变化能做出及时且准确的信号反馈。该离子传感纤维制备方法简便,具有工业化大规模的潜力,在智能健康监测、运动训练与优化、智能人机交互等领域均具有较大的发展潜力。

基于F-P光纤传感器的变压器油中双局部放电源定位研究

电力变压器作为电力系统中至关重要的能量转换设备,其稳定运行对于保障电能供应的可靠性具有重大意义。局部放电影响高压电气设备绝缘性能。局部放电在线监测不仅可以获取设备老化信息,还可以预测变压器寿命。局部放电源准确位置信息可以帮助检修人员制定精准维护计划,确保电力系统稳定,设备制造商可利用此信息优化结构和安装方法。变压器内部双局部放电源放电是一种更为复杂的故障类型,传统的检测方法难以准确捕捉到此类放电波形。F-P光纤传感器是一种新型的局部放电声学检测方式,该传感器结构小,灵敏度高,而且有较强的抗电磁干扰能力,可以内置于变压器内部实现复杂情况下的局部放电检测。在本研究中,研制了基于F-P光纤传感器的双局部放电源检测系统,采用基于多信号分类(MUSIC)测向原理的交叉定位算法,可以实现对变压器油中双局部放电源定位。总的来说,F-P光纤传感器阵列有较好的方向清晰度,可以实现准确定位。将该双局部放电源定位系统应用到了35 kV单相变压器模型上,验证了其对外绕组双局部放电源定位的有效性。

基于PMN-PT的宽带高灵敏双谐振式声发射传感器研究

声发射传感器被广泛应用于局部放电检测中,而基于PZT压电陶瓷的声发射传感器难以同时满足越来越高的灵敏度和带宽需求。该文设计了一种双谐振式声发射传感器,采用高性能铁电单晶PMN-PT作为压电振子,并使用谐振峰耦合,可同时提升灵敏度和带宽。所制备的传感器实现了76.2 dB的高灵敏度,20~105 kHz的大带宽,且具备良好的稳定性。对比基于PZT-5H的声发射传感器,其具有更高的灵敏度和信噪比。

双驱动自组装制备聚甲基丙烯酸甲酯嵌段聚4-乙烯基吡啶/多酚氧化酶多孔膜在酚类污染物检测中的应用

在呼吸图法的基础上引人静电作用,原位制备了功能高分子生物膜材料。聚甲基丙烯酸甲酯嵌段聚4-乙烯基吡啶(PMMA-b-P4VP)是一种两亲嵌段聚合物。亲水段P4VP和和亲水性的多酚氧化酶(PPO)在亲疏水性的驱动下同时转向了水相,形成一重驱动。调节PPO水溶液的pH值,使得PPO与电离的P4VP带异种电荷,发生静电吸引,实现二重驱动,在静电驱动下PPO跟随P4VP有序排列,更好地与酚类物质作用。膜厚度的测量结果表明,膜存在疏松的多孔状结构;接触角结果表明,更多疏水的PMMA在膜表面富集,P4VP转向膜内侧。提供了一种简便的制备方法得到能用于检测水体环境中酚类污染物电化学传感器,在测量儿茶酚溶液时线性范围为0.0010-0.030mmol^(L)-1,检出限为0.07μM。线性方程y=48.37x+0.08163,相关系数R=0.9967。存放30天后,电极对儿茶酚的响应电流仍能保持初始电流的87.4%。

基于功能化金属有机骨架材料的比率电化学传感器在检测领域的应用进展

比率电化学传感器将电流信号的比值作为输出信号,通过电流信号比值的变化实现目标物的定量检测,具有可靠性好、重复性高等优点。金属有机骨架(MOFs)材料是一种多孔配位聚合物,因比表面积、孔隙率、孔径等结构和性能优势备受学者关注。目前,基于MOFs材料的比率电化学传感器已广泛用于多种物质的检测,成为传统检测方法的潜在替代方法。为此,对比率电化学传感器的原理、分类、常用信号物质以及不同MOFs材料的性能进行总结,重点综述了基于功能化MOFs材料的比率电化学传感器在检测领域的应用进展(引用文献60篇)。

对3种典型检波器及其数据的几点看法

动圈式检波器与压电式检波器是当前石油地震勘探中应用最为广泛的两类检波器,典型代表包括动圈式速度检波器、水中压电式压力检波器以及陆上压电式加速度检波器。分析了3种检波器的物理结构、力学模型、等效电路以及传输函数,实际数据证明动圈式检波器拾取的地表振动速度与陆地压电检波器拾取的地表振动加速度在主要频带内是等效的,但后者一致性稍差。水中压电式检波器(简称水检)是压力型检波器,不是加速度型检波器,其与动圈式速度检波器或者MEMS加速度检波器(简称陆检)是组成双检海底电缆(OBC)与海底节点(OBN)施工、采用双检合并技术消除水层鸣震的装备基础。当前双检合并技术的几个假设前提,如地震波场是平面波场,检波器距离海底非常近但二者并不接触,不考虑耦合效应,不考虑检波系统的机电效应等,在实际生产中并不满足。因此,提高双检合并技术的实用性需要对以上假设条件进行更深入的研究并采取相应的工程措施。考虑到检波器的主要功能是“忠实地记录大地振动”,野外经由电路提频的做法不应提倡。此外,对比了容易混淆的两种检波器分类方法并清晰地展示了检波器的分类标准及其对数据的影响。

基于比色法和表面增强拉曼光谱双传感系统检测水中的芘

设计了一种基于AgNPs-AuNPs的核-卫星纳米结构检测水样中多环芳烃芘的比色和SERS双通道传感系统。首先将单巯基β-环糊精修饰到纳米金颗粒和纳米银颗粒的表面。受益于氧化态的四甲基联苯胺的触发,当体系中存在多环芳烃芘时,纳米颗粒会自组装形成AgNPs-pyrene-AuNPs的核-卫星结构。芘分子在其中充当分子桥的作用,拉近纳米粒子距离,使得纳米粒子发生一定的聚集。所以芘分子的个数直接影响AgNPs-pyrene-AuNPs的核-卫星结构数量,使溶液颜色发生变化,能够通过目测法建立溶液颜色与芘浓度的关系;组装形成的的核-卫星结构具有非常丰富的“热点”而表现出较强的表面增强拉曼光谱(SERS)活性,可通过SERS方法实现芘分子的高灵敏高特异检测。此结构可通过比色法和SERS方法实现水中芘的高灵敏高特异性检测。该方法可以在25 min内快速完成微量芘的检测,比色法对芘的检出限为3.4μmol·L^(-1), SERS法的检出限为0.42μmol·L^(-1)。根据上述原理,基于AgNPs-PAHs-AuNPs核-卫星结构的SERS传感器可用来检测水样中的多种多环芳烃。这一双通道传感系统提供了一种检测水样中多环芳烃芘的新方法,并为开发多路复用的传感系统提供了新的思路。

基于SMF-PDMS-DCF的柔性曲率传感器设计

为克服现有曲率传感器测量曲率范围小、灵敏度不高等缺陷,设计了一种以单模光纤(single mode fiber,SMF)和双芯光纤(double-core fiber,DCF)为干涉结构的SMF-PDMS-DCF柔性曲率传感器。该传感器使用聚二甲基硅氧烷(polydimethylsiloxane,PDMS)柔性材料作为耦合器,将单模光纤和双芯光纤软连接起来,利用PDMS材料和双芯光纤构成悬臂梁,使悬臂梁弯曲可以检测出曲率大小。经实验表明:曲率在0~4.1198 m^(-1)时,反射光的波长、光谱强度都和曲率之间具有良好的线性关系;从波长和曲率的关系看,灵敏度最高可达-0.3118 nm/m^(-1);从光谱强度和曲率的关系看,灵敏度最高可到-1.6715 dB/m^(-1)。

能耗均衡与节能的自适应水下路由协议

针对水下传感器网络中节点能耗不均衡和能量有限的问题,提出一种能耗均衡与节能的自适应水下路由协议ECBES(energy consumption balanced and energy saving adaptive underwater routing protocol)。构建双区非均匀分层拓扑。基于能耗均衡因子,利用拓扑和节点剩余能量计算节点转发优先级,实现自适应转发节点选择,均衡网络能耗。与此同时,通过候选转发区域各分区域中节点参与转发数据包的比例确定次优候选转发区域,将次优候选转发区域作为初始策略,利用策略迭代思想确定最优候选转发区域,保证投递率的同时减少不同网络规模中重复数据包的转发,降低网络的整体能耗。仿真结果表明,ECBES相比VBF、ES-VBF和ALRP,在不同节点数量下,节点死亡率均最低,在保证数据包投递率的同时,能耗最少。