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排序方式: 共有192条查询结果,搜索用时 31 毫秒
81.
82.
A potentiometric oxygen electrode was successfully used to produce a microbial biosensors with an extended response range, based on immobilised yeast cells (Saccharomyces ellipsoideus). The response for ethanol takes ca. 7 min for the steady-state method and 2 min for kinetic measurements. A linear calibration achieved over more than two decades of ethanol concentration. Selective determination of ethanol in the presence of non-volatile compounds was achieved using a second PTFE membrane to cover the biocatalytic layer. 相似文献
83.
One considers Hilbert space valued measures on the Borel sets of a compact metric space. A natural numerical valued integral of vector valued continuous functions with respect to vector valued measures is defined. Using this integral, different norms (we called them Monge–Kantorovich norm, modified Monge–Kantorovich norm and Hanin norm) on the space of measures are introduced, generalizing the theory of (weak) convergence for probability measures on metric spaces. These norms introduce new (equivalent) metrics on the initial compact metric space. 相似文献
84.
Illegal deforestation is a worldwide problem which may be alleviated through technological means of deforestation monitoring, e.g. wireless sensor networks capable of identifying chain-saw noise, performing sound source localization (SSL), and alerting the authorities to the location of the illegal deforestation activity. In this paper we evaluate the feasibility of performing SSL on low-power, energy-constrained, microphone-array-equipped sensor nodes (SNs) with the Delay-and-Sum (DS) beam-forming algorithm. Our work is the first application of this technique for chain-saw noise. We evaluate array configurations of 4, 8, and 16 microphones, and a multitude of DS algorithm configurations, utilizing chain-saw recordings from the ESC dataset, which is available online. We implement the DS algorithm as a digital circuit in a Xilinx Spartan-6 FPGA and analyze its energy consumption. Our analysis indicates that accurate chain-saw localization can be achieved with much simpler microphone arrays and DS configurations compared to previous work. Furthermore, adding FPGA-based SSL capability to the SN increases the energy consumption by less than 10%, compared to a baseline SN capable only of chain-saw identification through spectral analysis executed in software on the SN microcontroller. 相似文献
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87.
[2,2-dimethyl-4-(t-butyldimethylsiloxy)-3,4-dihydro-2H-pyran-6-yl] methanal (1) was synthesized from commercially available butopyronoxyl (2). The selectivity of reducing agents such as DIBAL-H and LiAlH4 towards butopyronoxyl was studied. Solvent effects were found to influence 1,2 versus 1,4 reduction. 相似文献
88.
Lucian Coroianu 《Numerical Functional Analysis & Optimization》2013,34(7):713-727
In this article, we investigate the local approximation and shape preserving properties in subintervals for the Meyer-König and Zeller max-product operators. The results obtained put in evidence that in the class of strictly positive continuous functions, the local properties of the nonlinear Meyer-König and Zeller max-product operators are much stronger and more general than those in the case of their linear counterparts. 相似文献
89.
Marcela Stoia Oana ?tef?nescu Gabriela Vlase Lucian Barbu-Tudoran Mirela Barbu Mircea ?tef?nescu 《Journal of Sol-Gel Science and Technology》2012,62(1):31-40
This paper presents a study regarding the formation of hybrid gels starting from tetraethyl orthosilicate (TEOS), polyvinyl
alcohol (PVA) and 1,3-propanediol (PD) and their thermal evolution to mesoporous silica matrices. The possibility of obtaining
homogenously dispersed cobalt ferrite inside the silica matrix starting from (TEOS–PVA–PD–Metal Nitrates) gels was also studied.
The formation of the hybrid gels TEOS/PVA/PD with different compositions was studied by FT-IR spectrometry and thermal analysis,
in order to evidence the interaction between the diol with the organic and the inorganic polymers. Both thermal analysis and
FT-IR spectrometry have evidenced the formation of physical and chemical interaction between polyols and the siloxane network.
Elemental mapping performed by SEM-EDX technique evidenced the formation of homogenous hybrids both in the presence of the
absence of 1,3-propanediol. SEM images of the powders obtained by annealing the hybrid xerogels at 600 °C have evidenced the
formation of mesoporous silica. By thermal treatment of the (TEOS–PVA–PD–Metal Nitrates) gels, 30%CoFe2O4/70%SiO2 (mass percent) nanocomposites uniformly dispersed in silica matrix with characteristic magnetic properties, have been successfully
synthesized. 相似文献
90.
Ana‐Maria Gurban Lucian Rotariu Virgil Emanuel Marinescu Camelia Bala 《Electroanalysis》2012,24(12):2371-2379
A ternary composite material based on Prussian blue, single‐walled carbon nanotubes and 1‐butyl‐3‐methylimidazolium hexafluorophosphate was prepared and tested for electrochemical detection of H2O2. The sensor allows amperometric detection of H2O2 at ?0.05 V, with a sensitivity of 137 mA M?1?cm?2. The nanocomposite provides a favorable microenvironment for immobilization of horseradish peroxidase (HRP). Determination of xenoestrogenic compounds was performed by enzymatic oxidation at the surface of modified screen printed biosensor in the presence of H2O2. The developed electrochemical biosensors exhibited high sensitivity, low detection limits, good operational and storage stability, for detection of 4‐t‐butylphenol, 4‐t‐octylphenol, 4‐n‐nonylphenol and 4‐n‐nonylphenol ethoxylate. 相似文献