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p. 509-518
Received: 5 September 2005 / Accepted: 28 November 2005 / Published: 1 December 2005
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| Download PDF Full-text (287 KB) Abstract: Imprinting is a flexible and straightforward technique to generate selective sensormaterials e.g. for mass-sensitive detection. Inherently, the strategy suits both molecularanalytes and entire micro organisms or cells. Imprinted polyurethanes e.g. are capable ofdistinguishing the different xylene isomers with very appreciable selectivity factors.Combining imprinted titanates with surface transverse wave resonators (STW) leads to apowerful tool for detecting engine oil degradation, which is an excellent example foroxidative deterioration processes in a highly complex matrix. Surface imprints withgeometrically equal cavities exhibit clear chemical selectivity, as can e.g. be seen throughthe example of different human rhinovirus (HRV) serotypes. Another example is a bloodgroup-selective sensor prepared by templating with erythrocyte ghosts. Both the bloodgroupA and B imprinted material selectively distinguish between blood groups A, B and O,whereas no difference in sensor signal has been observed for AB, where both blood groupantigen types are present on the cell surface.
p. 519-528
Received: 18 November 2005 / Accepted: 30 November 2005 / Published: 1 December 2005
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| Download PDF Full-text (893 KB) Abstract: WO3 and NiO-WO3 thin films of various thicknesses were deposited on anAl2 O3 -Si (alumina-silicon) substrate using high vacuum thermal evaporation. Afterannealing at 500oC for 30 minutes in air, the crystallanity and surface morphology of WO3 and NiO-WO3 thin films were investigated using X-ray diffraction (XRD) and ScanningElectron Microscopy (SEM). It is observed that the WO3 thin films were resulted in cracksbetween the polycrystalline grains and the grain growth was increased with increasingthickness causing deteriorated sensing characteristics of the films. On the other hand, anoptimum deposition of NiO on WO3 thin film has inhibited the grain growth and improvedthe sensitivity of the films. The inhibition is limited to a certain thickness of WO3 and NiOcontent (mol %) of inclusion and below or above this limitation the grain growth could notbe suppressed. Moreover, the deposition sequence of NiO and WO3 is also playing asignificant role in controlling the grain growth. A probable mechanism for the control ofgrain growth and improving the sensing property has been discussed.
p. 529-536
Received: 16 November 2005 / Accepted: 27 November 2005 / Published: 7 December 2005
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| Download PDF Full-text (126 KB) Abstract: A Chinese yellow wine classification method is proposed based on chemometricanalysis of voltammogram of copper electrode. The main components in Chinese yellowwine are alcohol, amino acids and carbon hydrates. In strong alkaline solution copperelectrode shows rich voltammetric responses to these components. Principal componentanalysis is employed to analyse voltammetric response of copper electrode to six Chinesewine samples in strong alkaline solution. The score plots show good discrimination of thesewine samples. In order to compress the original voltammetric data, a windowed time slicingmethod is investigated in this study. It greatly reduces the input data number and theresulted PCA plot still has good discrimination ability.
p. 537-545
Received: 8 June 2005 / Accepted: 10 December 2005 / Published: 15 December 2005
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| Download PDF Full-text (133 KB) Abstract: Amperometric detection of nitric oxide with ISO-NOPMC NO microsensors(WPI) is systemically studied in the six media including seawater. The linear range of themicrosensor for NO was from 10-6 to 10-9 mol/l and the detection limit was4.2×10-10 mol/L(S/N=2). With this method, we provide preliminary evidence that NOproduction could be a general attribute of marine alga (Haeterosigma akashiwo).Experiment conducted with inhibitor of uncoupler 2,4-DNP (2,4-dinitropheno) revealed thatNR (nitrate reductase) activity is responsible for NO formation.
p. 546-579
Received: 5 December 2005 / Accepted: 15 December 2005 / Published: 15 December 2005
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| Download PDF Full-text (725 KB) Abstract: High performance planar electromagnetic sensors, their modeling and a fewapplications have been reported in this paper. The researches employing planar typeelectromagnetic sensors have started quite a few years back with the initial emphasis on theinspection of defects on printed circuit board. The use of the planar type sensing system hasbeen extended for the evaluation of near-surface material properties such as conductivity,permittivity, permeability etc and can also be used for the inspection of defects in the nearsurfaceof materials. Recently the sensor has been used for the inspection of quality ofsaxophone reeds and dairy products. The electromagnetic responses of planar interdigitalsensors with pork meats have been investigated.
p. 580-593
Received: 2 September 2005 / Accepted: 12 December 2005 / Published: 16 December 2005
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| Download PDF Full-text (370 KB) Abstract: Polypyrrole(PPy) nanowire modified electrodes were developed by template-freeelectrochemical method based on graphite electrode. The modified electrode wascharacterized by their amperometric response towards nitrate ions. Before reduction ofnitrate ions, electrochemical solid-phase extraction (EC-SPE) of nitrate in/on modifiedelectrodes was conducted. It is found that the unusual nanowired structure of polypyrrolelayer (instead of well known cauliflower structure) allows us to increase the effectivesurface area of the electrode and subsequently the sensitivity. And the effects ofelectrochemical preparation parameters of PPy nanowire modified electrodes on theircorresponding characters were evaluated. The experimental results show that theelectrochemical preparation parameters of the modified electrodes such as scan rate,polymerization potential, temperature of polymerization solution and polymerization timehave significantly effects on the morphology of PPy nanowires and subsequently effectivesurface area of the electrode and electroreduction current density of nitrate. Thedetermination sensitivity may be varied according to the modification parameters. Under acertain polymerization conditions, the corresponding sensitivity reaches 336.28 mA/M cm2 and the detection limit is 1.52×10-6 M. The proposed method was successfully applied in thedetection of nitrate in the real samples.
p. 594-603
Received: 6 October 2005 / Accepted: 19 December 2005 / Published: 20 December 2005
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| Download PDF Full-text (327 KB) Abstract: Atomic force and high resolution scanning tunneling analyses were carried out onnanostructured WO3 films. It turned out that the band gap measured by scanning tunnelingspectroscopy at surface is lower than the band gap reported in the literature. This effect isattributed to the high density of surface states in this material, which allows tunneling intothese states. Such a high density of surface states pins the Fermi level resulting in modestsurface activity at room temperature. Photo activation of WO3 results in unpinning of theFermi level and thereby in higher chemical activity at surface.
p. 604-612
Received: 4 March 2005 / Accepted: 19 December 2005 / Published: 21 December 2005
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| Download PDF Full-text (125 KB) Abstract: A new atropine drug-FET sensor, which was made of an ISFET (ion sensitivefield effect transistor) and a drug sensitive membrane prepared by adding electric activematter to a β-cyclodextrin solution, was developed. The pH influence, selectivity, responsecurve, reproducibility, stability, response time and life of this sensor were investigated. Apreliminary application of the sensor was discussed as well. The experimental resultsindicated that the sensor showed a Nernst response to atropine with a slope of 58.0mV/decade over the concentration range of 5.0×10-3 - 1.0×10-6 mol/L and the pH rangeof 5.0-8.5. The sensor detection limit was 8.0×10-7 mol/L. The performance of this sensorwas very stable when it was used to determine atropine concentration in a medicinalinjection. The obtained results agreed well with the pharmacopoeia method.
p. 613-632
Received: 5 December 2005 / Accepted: 21 December 2005 / Published: 21 December 2005
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| Download PDF Full-text (477 KB) Abstract: In this paper, a sensor to measure the rollover angle of a car under performance testsis presented. Basically, the sensor consists of a dual-axis accelerometer, analog-electronicinstrumentation stages, a data acquisition system and an adaptive filter based on a recursiveleast-squares (RLS) lattice algorithm. In short, the adaptive filter is used to improve theperformance of the rollover sensor by carrying out an optimal prediction of the relevant signalcoming from the sensor, which is buried in a broad-band noise background where we have littleknowledge of the noise characteristics. The experimental results are satisfactory and show asignificant improvement in the signal-to-noise ratio at the system output.
p. 633-643
Received: 15 September 2005 / Accepted: 22 December 2005 / Published: 23 December 2005
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| Download PDF Full-text (98 KB) Abstract: An isoperibolic calorimetric cell is built with glass surrounded by plastic insulation. Thecell has a lid on which a thermistor thermometer, an electric resistance to provide the cell with definitequantities of electric work and a container for a glass ampoule, are placed. For measuring the thermalchanges, an NTC thermistor, which provides an electric resistance signal that varies with temperature,is used. Calibration curves of the thermistor and of the stabilization of the system signal in thermalequilibrium are shown, which enable the observation of a good insulation. The calorific capacity of thesystem with water, with a value of 206.7 ± 0.7 J °C-1 is determined; the solution enthalpy for propanolwaterand KCl-water systems is obtained, which shows the behavior of the cell before exothermic andendothermic effects, respectively.
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