基于CNTs/PDMS介电层的柔性压力传感特性研究

提出一种基于MEMS工艺的柔性压力传感器制备方法.采用MEMS工艺制备柔性压力传感器模板,结合纳米压印技术、射频磁控溅射技术和PDMS软光刻工艺在PDMS柔性基底上制备了具有"V"型阵列微结构的Ag薄膜平行板电极,基于碳纳米管(CNTs)/PDMS聚合物的压电容特性,制备出电容式柔性压力传感器.针对不同尺寸的压力传感器进行对比测试,本文制作的压力传感器的灵敏度能够达到3.98% kPa-1,具有良好的重复性,在智能穿戴和电子皮肤等方面有着广阔的应用前景.     

石墨烯/聚二甲基硅氧烷三维非织造结构压阻柔性压力传感器

压阻式压力传感器是可穿戴器件中的关键元件。由于优异的弹性性能,本文以三维聚酯非织造布作为基材,还原氧化石墨烯(rGO)作为活性材料,聚二甲基硅氧烷(PDMS)作为柔性材料,组装三维(3D)压阻式压力传感器。该传感器具有良好的感应特性,包括短响应时间(120ms)和微弱的迟滞性(6.8%)。此外,该压力传感器可以用于检测人体的关节以及喉咙的运动情况。因此,该压阻传感器成本低、灵敏度高、耐久性优良,可以作为穿戴智能设备的理想的三维压阻式压力传感器。     

碳纳米管/PDMS复合材料柔性阵列压力传感器制备与实验

以碳纳米管（CNTs）作为导电填料,聚二甲基硅氧烷（PDMS）为基体材料,采用溶液法制备出CNTs/PDMS导电复合材料。研究了碳纳米管浓度对复合材料的电学特性和压阻特性的影响规律,得到碳纳米管在PDMS中的渗滤区域。通过复合材料的压力灵敏度优化碳纳米管浓度。以制备的复合材料为敏感材料,FPCB工艺加工的柔性基板为电极,设计制备了一种简单结构和工艺的柔性阵列压力传感器。用零电势法设计了阵列电阻读出电路与LabVIEW实现的上位机配合,实现信号读取和显示。最后通过一个应用实例表明,该柔性阵列压力传感器及信号处理系统可以实现压力分布与大小的实时监测,可为柔性阵列压力传感器设计与制备提供参考。     

基于 ＧＮＰｓ/ ＰＤＭＳ 复合薄膜的柔性压阻传感器制备及性能研究

目前柔性压力传感器已被用于众多领域,其中压阻薄膜是柔性压力传感器的核心。本文将石墨烯纳米片（GNPs）与聚二甲基硅氧烷（PDMS）复合,通过倒模的方法制备压阻薄膜,经测试,GNPs浓度为8%时,材料具有较好的性能。以此为基础,制备了压敏结构间距为1.2 mm,直径大小为1.0 mm的GNPs/PDMS基压阻传感器,经测试,所制备的传感器加载响应为340 ms,卸载响应速度为260 ms,并具有较好的稳定性,同时,基于该压阻式柔性压力传感器实现了人体手腕关节处压力信号的测试。     

陶瓷压阻式机油压力传感器研制

针对传统滑线式机油压力传感器不足,设计制作了一种陶瓷压阻式机油压力传感器.利用自搭建的温度压力测试系统对其进行了标定与测试,实验结果显示:其综合检测精度(线性、迟滞、重复性等)达到0.925％F.S,完全符合压力传感器通用技术条件规定的综合误差≤2％F.S的要求,并通过了2～3倍量程的过载、爆破压力测试,性能稳定可靠.加之陶瓷芯片具有耐腐蚀、抗磨损、成本低廉等优点,该传感器可广泛应用于机油压力及其他相关场合的压力检测中.     

基于RFID的无线无源柔性压力传感器研究

提出了一种基于RFID反向散射耦合原理的无线无源柔性压力传感器。该传感器以铁氧体薄膜作为反射层,柔性海绵作为中间层,RFID标签作为数据传输层。通过有限元方法对传感器的增益和杨氏模量进行仿真,并使用压力测试系统测量传感器的灵敏度,最后得到了同样的结论：在相同厚度下中间层为低密度海绵的传感器灵敏度更高。此外对传感器进行了一系列性能测试,得到传感器最大工作距离为10 cm,在温度测量范围(25℃～45℃)误差为0.91%,在湿度测量范围(43%RH～82%RH)误差为0.89%。该无线无源柔性压力传感器结构简单、生产成本低,增加了无线无源传感器在近场范围内的测量距离。在医用绷带压力检测、足底压力检测等智能医疗领域具有良好的应用前景。     

MEMS硅铝异质结构压力传感器的设计制作与测试研究

金属半导体异质混合结构是一种特殊的压阻结构,其具有高于传统MEMS压阻式压力传感器的压阻性能.鉴于此,设计和研究了一种由掺杂单晶硅和金属铝混合形成的MEMS异质结构压力传感器.首先结合理论模型和ANSYS有限元模拟仿真分析了硅铝异质结构传感器的灵敏度特性,然后通过MEMS工艺制作了硅铝异质结构压力传感器芯片,并对其进行了封装与测试.实验结果表明,硅铝异质结构压力传感器的灵敏度可达到0.1168 mV/(V·kPa),而利用参考结构能够明显减小环境温度对其性能的影响.在此基础之上,本文采用基于遗传算法改进的小波神经网络对传感器的温度漂移和非线性误差进行了补偿,补偿后硅铝异质结构压力传感器的测量误差小于±1.5％FS.     

基于高分子聚合物的柔性传感器研究进展

对基于高分子聚合物的柔性传感器的研究进展进行了概述.从传感器的种类、材料、结构设计、制备工艺、传感原理等多个角度进行分析,并对这些传感器的主要性能(灵敏度、稳定性与重复性、响应时间、迟滞性等)进行评估.重点讨论基于高聚物的柔性传感器在可穿戴设备、柔性驱动以及疾病预防等领域内的应用,总结了当前国内外传感器技术研究所面临的...     

铁基非晶合金整体磁芯轴向拉压型测力传感器的研究与设计

将铁基非晶态合金薄带缠绕成圆柱型应力敏感磁芯,基于压磁效应,使同一传感器实现既能测量拉力,又能测量压力.介绍了传感器的结构和原理,推导出传感器的输出特性方程.通过拉伸和压缩试验,分析了传感器的最佳激磁磁场强度、静态特性以及温度特性.试验数据显示,传感器测量拉伸和压缩载荷时,最大非线性误差分别为0.41％F.S和1.12％F.S,重复性误差分别为0.86％F.S和0.85％F.S,平均灵敏度为0.71 mV/kN和1.16 mV/kN.     

石墨烯柔性压力/应变传感器的研究进展

柔性压力/应变传感器可以贴附在物体表面,测量其表面压力或应变,可用于人体脉搏检测、表情识别和运动监测等,在健康监护、医疗诊断等方面有广阔的发展空间.石墨烯柔性压力/应变传感器比普通压力/应变传感器性能更为优异,其测量范围宽、灵敏度高且尺寸仅为纳米级.综述了石墨烯压力/应变传感器在近几年来的研究进展及应用情况,重点讨论了基于石墨烯材料的电容法、激光诱导法、3D海绵法、纸基法、水凝胶法的压力/应变传感器的制备方法及性能差异.最后简要指明石墨烯柔性压力/应变传感器未来的研究方向.     

M/G/c/K blocking probability models and system performance

An exact solution for the M/G/c/K model is only possible for special cases, such as exponential service, a single server, or no waiting room at all. Instead of basing the approximation on an infinite capacity queue as is often the case, an approximation based on a closed-form expression derivable from the finite capacity exponential queue is presented. Properties of the closed-form expression along with its use in approximating the blocking probability of M/G/c/K systems are discussed. Extensive experiments are provided to test and verify the efficacy of our approximate results.     

设计模式变体的描述与验证*

为解决标准设计模式演化后难以检测的问题,引入设计模式变体思想,以Bridge模式为例,给出了八种常用的变体实现,并以人工形式挖掘了四种开源系统中Bridge模式变体的基准数,接着在Apache Ant1.6.2与JHotDraw5.1开源系统中通过六种主流设计模式检测工具进行了变体检测实验。试验结果表明,FCA-CBR方法简单有效,对2种开源系统中Bridge模式变体检测的精确率达到60%与48.1%,与先前方法相比有了较大的提高。     

(r∞, n12, s12) measurements on the 2-CPU CRAY X-MP

We report performance measurements made on the 2-CPU CRAY X-MP at ECMWF, Reading. Vector (SIMD) performance on one CPU is interpreted by the two parameters ($\text{r}{}_{\mathrm{\infty }}\text{, n}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$), and we find for dyadic operations using FORTRAN $\text{r}{}_{\mathrm{\infty }}\text{= 70}\text{Mflop/s}\text{, n}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 53}\text{flop}$. All vector triadic operations produce $\text{r}{}_{\mathrm{\infty }}\text{= 107}\text{Mflop/s}\text{, n}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 45}\text{flop}$; and a triadic operation with two vectors and one scalar gives r_∞ = 148 Mflop/s and $\text{n}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 60}\text{flop}$. MIMD performance using both CPUs on one job is interpreted with the two parameters ($\text{r}{}_{\mathrm{\infty }}\text{, s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$), where $\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ is the amount of arithmetic that could have been done during the time taken to synchronize the two CPUs. We find, for dyadic operations using the TSKSTART and TSKWAIT synchronization primitives, that r_∞ = 130 Mflop/s and $\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 5700}\text{flop}$. This means that a job must contain more than ～ 6000 floating-point operations if it is to run at more than 50% of the maximum performance when split between both CPUs by this method. Less expensive synchronization methods using LOCKS and EVENTS reduces $\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ to 4000 flop and 2000 flop respectively. A simplified form of LOCK synchronization written in CAL code further reduces $\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ to 220 flop. This is probably the minimum possible value for synchronization overhead on the CRAY X-MP.     

Geom/G/1/n system with LIFO discipline without interrupts and constrained total amount of customers

Consideration was given to the discrete-time queuing system with inversive servicing without interrupts, second-order geometrical arrivals, arbitrary (discrete) distribution of the customer length, and finite buffer. Each arriving customer has length and random volume. The total volume of the customers sojourning in the system is bounded by some value. Formulas of the stationary state probabilities and stationary distribution of the time of customer sojourn in the system were established.     

Complex random sample scheduling and its application to an N/M/F/Fmax problem

“Complex Random Sample Scheduling(CRSS)” was proposed in this paper as an efficient heuristic method for solving any permutation scheduling problems. To show the effectiveness of the proposed CRSS, it was applied to an N-job, M-machine, permutation flowshop scheduling problem to minimize makespan, N/M/F/F_max. Numerical experiments made it clear that the proposed CRSS provides a schedule very close to the near-optimal schedule obtained by the existing promising heuristic methods such as taboo search and simulated annealing, within less computation time than these heuristic methods.     

Efficient implementation of Johnson''s rule for the n/2/F/Fmax scheduling problem

Several efficient algorithms of O(n log n) computational complexity, for the Johnson's rule to schedule a set of simultaneously available jobs on two machines in a flowship to minimize the maximum job flowtime have appeared in the literature. A modified version of one of these algorithms is presented which not only simplifies the programming effort for implementation but is also able to generate all possible optimal sequences obtainable from Johnson's rule.     

On the M/Ck/1 queue

We obtain the exact analytic expression of the probability distribution of the number of units in a single server queue with Poisson arrivals and Coxian service time distribution (notated as M/C_k/1). A recursive procedure for calculating this probability distribution is given. The well-known queues M/E_k/1 and M/D/1 are re-derived as special cases of the M/C_k/1 queue. Finally, the cases of M/C₂/1 and M/C₃/1 are fully worked out.