Manganese(II)-selective PVC membrane electrode based on a pentaazamacrocyclic manganese complex

Manganese(II) complex of 14,16-dimethyl-1,4,7,10,13-pentaazacyclohexadeca-13,16-diene [Me₂(16)dieneN₅] (I) was synthesized and used in the fabrication of Mn²⁺-selective ISE membrane in PVC matrix. The membrane having Mn(II) macrocyclic complex as electroactive material along with sodium tetraphenylborate (NaTPB) as anion discriminator and dioctylphthalate (DOP) as plasticizer in poly(vinylchloride) (PVC) matrix was prepared for the determination of Mn²⁺. The best performance was observed by the membrane having Mn(II) complex–PVC–NaTPB–DOP in the ratio 1:5:1:3. The sensor worked well over a concentration range of 1.25 × 10⁻⁵ to 1.0 × 10⁻¹ M between pH 3.0 and 8.0 and had a fast response time of 20 s with a lifetime of 4 months. Their performance in partially non-aqueous medium was found satisfactory up to 30% (v/v) alcoholic content. Electrodes exhibited excellent selectivity for Mn²⁺ ion over other mono-, di-, trivalent cations. It can also be used as indicator electrode in the potentiometric titration of Mn²⁺ against EDTA.     

Novel erbium (III)-selective fluorimetric bulk optode

For the first time a highly sensitive and selective fluorimetric optode membrane was prepared for the determination of trace amounts of Er(III) ions. The Er(III) sensing system was constructed by incorporating 5-(dimethylamino) naphthalene-1-sulfonyl-4-phenylsemicarbazide (L) as a neutral Er(III)-selective fluoroionophore, in the plasticized PVC-membrane containing sodium tetraphenyl borate as a lipophilic anionic additive. The response of the optode is based on the strong fluorescence quenching of L by Er³⁺ ions. At a pH value of 5.0, the proposed optode displays a wide concentration range of 1.0 × 10⁻¹⁰ to 1.0 × 10⁻² M, with a relatively fast response time of less than 50 s. In addition, to high stability and reproducibility, the sensor shows a unique selectivity towards Er³⁺ ion with respect to common cations. The proposed optode was applied successfully to the trace determination of erbium ion in binary mixture and water samples.     

四对溴苯基铂卟啉PVC敏感膜氧传感器的研究

该文研制了一种新型氧敏感膜,其敏感物质为四对溴苯基铂卟啉,支持体系为PVC粉.该敏感膜是基于四对溴苯基铂卟啉在不同氧气浓度的环境中的荧光强度的变化而工作的.其最大激发波长与发射波长分别为515 nm和664 nm.文中检测了该敏感膜的稳定性,重现性等性质,发现其对分子氧的响应值I0/I100=52,其中I0是敏感膜在纯氮气氛围中的荧光强度,I100为其在纯氧气氛围中的荧光强度.该敏感膜具有良好的重现性及稳定性.     

Highly sensitive and linear calibration optical fiber oxygen sensor based on Pt(II) complex embedded in sol-gel matrix

A simple, low-cost technique for fabrication of high performance optical fiber oxygen sensor is described. An organically modified silicate (ORMOSIL) as a matrix for the fabrication of oxygen sensing film was produced. The technique is based on coating the end of an optical fiber with ORMOSIL composite xerogel films film sequestered with luminophore platinum (II) meso-tetrakis(pentafluorophenyl)porphyrin (PtTFPP) prepared by a sol-gel process. The composite xerogels studied are 3,3,3-trifluoropropyltrimethoxysliane (TFP-TriMOS) or n-propyltrimethoxysilane (n-propyl-TriMOS)/tetraethylorthosilane (TEOS)/n-octyltriethoxysilane (Octyl-triEOS). Results show that, expect for PtTFPP-doped TFP-TriMOS or n-propyl-TriMOS/TEOS/Octyl-triEOS composite xerogels show the high sensitivity and linear Stern-Volmer relationship which indicate the homogenous environment of the luminophore. The sensitivities of the two oxygen sensors are quantified in terms of the ratio I_N2/I_O2, where I_N2 and I_O2 represent the detected fluorescence intensities in pure nitrogen and pure oxygen environments, respectively. The experimental results reveal that the PtTFPP-doped TFP-TriMOS/TEOS/Octyl-triEOS and n-propyl-TriMOS/TEOS/Octyl-triEOS oxygen sensors have sensitivities of 101 and 155, respectively. The experimental results confirm that the current oxygen sensors exhibit the linear Stern-Volmer plots and high-sensitive based on the oxygen indicator embedded in TFP-TriMOS or n-propyl-TriMOS/TEOS/Octyl-triEOS composite xerogels.     

基于Au—Ni复合材料的新型葡萄糖传感器的研究

利用新型Au—Ni复合材料,通过壳聚糖将Au—Ni复合材料修饰到电极表面．制备了一种新型的用于葡萄糖检测的电化学传感器。以XRD表征了Au—Ni材料,以循环伏安法,交流阻抗法,计时电流等电化学方法研究了此传感器的电化学特性。研制的电极对葡萄糖检测的线性范围为2．5×10^-9．5×10^-4mol／L,检测限为lxl0...     

无线传感网中基于能量矩阵的多簇头分簇算法

在能量异构的无线传感器网络环境下,提出了一种基于能量矩阵的剩余能量预测模型和新的聚簇路由协议。模型中引入卡尔曼过滤算法,协议中节点通过建立相邻节点剩余能量预测机制,使选举簇头节点的概率与节点当前剩余能量直接相关,以均衡节点的能量消耗,延长网络寿命。此外,还通过多簇头方法,提高数据传输可靠性。仿真实验结果表明,LEACH-EM协议在延长网络生命周期和减少能量消耗上比其他协议有了很大改善。     

基于关系矩阵的主被动传感器统计融合算法

针对传感器对目标跟踪时观测噪声非高斯问题,提出了一种基于关系矩阵的主、被动传感器量测统计融合算法.采用方差加权距离处理传感器量测噪声非高斯问题,运用传感器综合融合度构建关系矩阵,并且在门限附近采用椭圆模糊处理技术,利用Perron-Frobenius定理计算量测融合过程中每个传感器的权重.仿真结果表明当传感器观测噪声具有非高斯特性时,基于关系矩阵的主被动传感器统计融合算法和传统的融合算法相比扰动较小,具有较好的稳定性,可用于改善跟踪系统的抗干扰能力.     

无线传感器网络中基于LU分解的分簇密钥管理方法

提出了一种基于LU矩阵分解的密钥管理方案。该方案借助于LU矩阵来完成密钥预分配,使得所有的簇头间以及节点和它的簇头间都能进行安全通信。分析表明,该方法占用较小密钥存储空间,同时支持网络的拓扑结构变化,能动态地管理密钥信息,从而解决了密钥泄露等问题。     

Fabrication of a highly selective Eu(III) membrane sensor based on a new S–N hexadentates Schiff''s base

A novel potentiometric membrane Eu (III) ion sensor is described based on a new S–N hexadentates Schiff's base, bis(thiophenol)butane2,3-dihydrazone (SNSB). The sensor exhibited a Nernstian response over a concentration range of 1.0 × 10⁻⁵ to 1.0 × 10⁻² M, with a detection limit of 5.0 × 10⁻⁶ M. The best performance was achieved with a membrane composition of 30% PVC, 63% o-nitrophenyloctyl ether (NPOE), 5% SNSB, and 5% (0.010 mmol) potassium tetrakis(p-chlorophenyl) borate (KTpClPB). It was found that in the pH range of 3.0–8.5, the potential response of the sensor was not affected by the pH. Furthermore, the electrode presented satisfactory reproducibility, very fast response time (<5 s), and relatively good discriminating ability for Eu(III) ions with respect to many common cations and lanthanide ions, including sodium, potassium, magnesium, calcium, copper, nickel, cobalt, zinc, lead, lanthanum, cerium, gadolinium, samarium, ytterbium, presidium, terbium, neodymium, holmium, erbium, thulium, lutetium, dysprosium, iron and chromium metal ions. The sensor was applied to the determination of fluoride ions in two mouth wash preparations and binary mixtures.     

表面活性剂在PVC膜上吸附的压电传感检测

在液隔电极式压电传感器表面修饰聚氯乙烯(PVC)膜,实时监测十二烷基苯磺酸钠在修饰膜表面吸附过程中的质量变化,获得吸附/脱附速率常数、平衡常数、饱和吸附量等参数,并讨论盐浓度的影响。     

Construction of a highly selective PVC-based membrane sensor for Ce(III) ions

A highly Ce(III) ion-selective poly vinyl chloride (PVC) membrane sensor based on N′-[(2-hydroxyphenyl)methylidene]-2-furohydrazide (NHMF) as an excellent sensing material is successfully developed. The electrode shows a good selectivity for Ce(III) ions with respect to most common cations including alkali, alkaline earth, transition and heavy metal ions. The proposed sensor exhibits a wide linear response with a slope of 19.4 ± 0.3 mV/decade over the concentration range of 1.0 × 10⁻⁵ to 1.0 × 10⁻¹ M, and a detection limit of 7.6 × 10⁻⁶ M of Ce(III) ions. The sensor response is independent of pH in the range of 3.5–10.0. The proposed electrode was applied as an indicator electrode in potentiometric titration of Ce(III) ions with EDTA and C₂O₄². It was also successfully applied in the determination of cerium ions in aqueous samples.     

Fabrication of a highly selective and sensitive Gd(III)-PVC membrane sensor based on N-(2-pyridyl)-N′-(4-nitrophenyl)thiourea

In this work we report the development of a highly selective and sensitive Gd(III) membrane based on N-(2-pyridyl)-N′-(4-nitrophenyl)thiourea (PyTu4NO₂) as an excellent neutral ion carrier. The Gd(III) sensor exhibits a Nernstian slope of 19.95 ± 0.3 mV per decade over the concentration range of 3.0 × 10⁻⁷ to 1.0 × 10⁻¹ M, and a detection limit of 3.0 × 10⁻⁷ M of Gd(III) ions. The potentiometric response of the sensor is independent of the solution pH in the range of 4.0–9.0. It manifests advantages of low detection limit, fast response time (10 s), and most significantly, very good selectivity with respect to a number of lanthanide ions (La, Ce, Sm, and Eu ions). It can be used at least for a period of 8 weeks without any significant divergences in its potential response. To assess its analytical applicability the proposed Gd(III) sensor was successfully applied as an indicator electrode in the titration of Gd(III) ion solutions with EDTA and for the determination of the fluoride ion in two mouth wash preparations. It was also used for the direct monitoring of Gd(III) ions in binary mixtures.     

A printable glucose sensor based on a poly(pyrrole)-latex hybrid material

A printable glucose sensor was obtained by immobilisation of glucose oxidase onto the surface of poly(pyrrole)-coated latex spheres, which were mixed with a conducting ink. The obtained hybrid material was able to amperometrically detect glucose under aerobic as well as anaerobic conditions, without the use of electron mediators. Since all of the steps involved in the preparation of this latex-poly(pyrrole)-based ink are performed in solution, in-expensive mass production will be possible. A possible mechanism for this sensor is proposed based on the direct communication between the enzyme and the conducting polymer under anaerobic conditions.     

无线传感器网络环境下基于卡尔曼滤波的PTP协议

作为分布式系统的重要组成部分,精确时间同步是对时间敏感的工业无线网络的核心技术.基于时间信息包交换的IEEE 1588精确时间同步协议（PTP）主要针对有线网络提出,其同步精度受制于时间戳的精度和传输延迟抖动.在无线传感网中,节点难以获取精确时钟戳,同时由于信道共享、包冲突和信道衰落,无线网络的传输延迟抖动非常明显. 研究了无线网络中PTP的性能与时间戳精度之间的关系,提出了一个自回归模型来描述时钟漂移,将PTP中的包交换过程抽象为一组状态空间方程,将延迟抖动等作为观测噪音,从而利用卡尔曼滤波器予以滤除.仿真结果表明,在不同时间戳精度和延迟抖动下,卡尔曼滤波能有效改善时钟误差和稳定性.     

Preparation of PCLT/P(VDF-TrFE) pyroelectric sensor based on plastic film substrate

Nanosized lead titanate doped with calcium and lanthanum (PCLT) powder obtained by the sol–gel method was homogeneously mixed with vinylidene fluoride-trifluoroethylene [P(VDF-TrFE)]. The nanocomposite PCLT/P(VDF-TrFE) film was used as the sensing film for pyroelectric sensors, whose detective merit was about 22.4% higher than that of sensors using pure P(VDF-TrFE). A 35 nm ITO film was deposited as the bottom electrode on PET plastic film substrate, on which PCLT/P(VDF-TrFE) was prepared by spin-coating, and Ni–Cr film was chosen as the upper electrode. The PET plastic film substrate could effectively decrease the thermal conductivity of the element and the ITO bottom electrode could reflect the infrared irradiation. The voltage responsivity was increased and the thermal fluctuation noise of the pyroelectric element was decreased significantly. The experimental results indicated that the specific detectivity of PCLT/P(VDF-TrFE) pyroelectric sensors based on PET film substrate reached 3.4E7 cm Hz^1/2 W⁻¹, more than two orders of magnitude higher than that of the sensors on bulk silicon substrate formed under the same conditions.     

基于权重动态离散模型的WSNs定位算法

针对测距误差和距离权重对定位误差的影响,提出一种离散距离权重动态修正的定位算法。算法首先分区域获取动态路径损耗指数,建立接收信号强度测距简化数学模型,抑制接收信号强度测距误差。然后将静态距离权重因子离散化,为离散距离权重匹配动态权重系数,并在划定的动态取值范围内寻找最优权重系数,权重系数与接收信号强度正相关。基于MATLAB平台仿真结果表明,与其他算法相比,该算法能够较好地抑制接收信号强度测距的误差影响,显著降低平均定位误差,提高定位精度。     

矩阵池在传感器网络密钥预配置方案中的应用

借鉴传感器网络中基于密钥矩阵密钥对预配置方案,设计出一个应用于传感器网络的高效密钥对预配置方案：应用矩阵池的密钥预配置方案。该方案提出了矩阵池的概念,将密钥的预配置建立在多个密钥矩阵之上,节省了节点的存储空间,增强了网络的可扩展性。将加密传输机制应用到密钥的传输过程中,增强了密钥传输过程中的安全性。通过本文的分析可以看出该方案有一些优良的特性,包括两节点间能以很高的概率成功建立密钥对、对入侵有较强的鲁棒性、低通讯量。     

Electrochemical copper (II) sensor based on self-assembled 4-amino-6-hydroxy-2-mercaptopyrimidine monohydrate

A 4-amino-6-hydroxy-2-mercaptopyrimidine monohydrate (AHMP)-based self-assembled monolayer (SAM) was formed on the gold electrode surface. Ellipsometric measurements evidenced the SAM formation on the gold electrode surface. The structural integrity of the modified gold electrode was also characterized by insulating properties of the SAM that were detected by cyclic voltammetry. The results of cyclic voltammetry showed that the SAM, which was formed by assembly of AHMP, was stable but did not completely block the redox-activity of ferrocene and K₃[Fe(CN)₆]/K₄[Fe(CN)₆]. In contrast completely blocked redox-activity was observed after the treatment of AHMP-based SAM with saturated solution of 4-formylphenylboronic acid in 1,4-dioxan. The modified electrodes exhibited a selective response towards Cu(II) ions in the presence of some interfering ions such as Cd(II), Co(II), Fe(II), Ni(II) and Pb(II). This study is the first scientific report on the application of AHMP-modified electrode as a selective Cu(II) sensor in the presence of some interfering cations.     

A miniature bio-inspired optic flow sensor based on low temperature co-fired ceramics (LTCC) technology

Low temperature co-fired ceramics (LTCC) technology is classically used in the field of radio frequencies to make items such as miniature transceivers for handheld devices. Here we harness the LTCC technology to autonomous micro-aerial vehicles (MAVs), a field in which small size and low mass are at a premium. Designing autonomous MAVs will be a highly challenging issue during the next few decades. Bio-inspired optic flow sensors, also known as elementary motion detector (EMD) circuits, have proved to be efficient means of providing animals and robots with visual guidance ability. The LTCC technology gives a good trade-off between the need for reliable optic flow sensors and the need for small-sized multiple electronic components. Comparisons with other technologies (PCB, analogue VLSI) show that LTCC technology is one of the most reliable solutions to the problem of obtaining reliable electronic EMDs that are small enough (area 7 mm × 7 mm) and light enough (mass 0.2 g) to be accommodated on-board a MAV. The output from our LTCC based optic flow sensors is largely invariant with respect to both contrast and spatial frequency.     

Data forwarding based on sensor device constraints in wireless multimedia sensor networks

A variety of data forwarding schemes have been proposed for wireless multimedia sensor networks where energy awareness and reliability are essential design issues. This paper proposes a data forwarding mechanism based on sensor device constraints in wireless multimedia sensor networks. A dynamic path cost function is defined considering the constraints and characteristics of wireless multimedia sensor networks. The cost function is applied to ZigBee mesh routing, and the performance of the proposed method is evaluated using a QualNet network simulator.