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A necessary and sufficient condition for the matrix equation to be consistent is established, and if it is, a representation of the general solution is given, thus generalizing earlier results concerning the equation . 相似文献
3.
Most of the potentiometric sensing electrodes offer detection limits of the order of approximately 1 micromol L(-1) rarely stretching down to 0.1 micromol L(-1). Recent advances have made it possible to bring these levels down to 0.01-10 nmol L(-1) for some inorganic ions. Most of these electrodes (barring a few) have come up to expectations in terms of selectivity in spite of significant strides made in the design and synthesis of novel chemical receptors. Imprinted polymers or plastic antibodies which rely on lock and key mechanism can, in principle, selectively rebind and sense a particular analyte in a host of other analogous species of similar size, shape and geometry. Thus, the integration of imprinted polymers with potentiometric transducers has immense potentialities in the fabrication of commercial sensing devices. This review gives an overview of research efforts made so far in this direction, critically discusses the virtues and vices and presents the futuristic scenario on imprinted polymer based potentiometric sensors. 相似文献
4.
This paper reports the results of the study of anisotropy in elastic wave propagation in single crystal superconducting BSCCO.
The inverse and group velocities of elastic waves propagating in different directions have been computed and the corresponding
slowness and ray velocity surfaces plotted, taking elastic constant data from literature. In addition, the phenomenon of phonon
focussing has been investigated in this material by computing the phonon enhancement factor along different directions in
spherical polar coordinates. The abnormally high values in phonon enhancement factor exhibited in certain directions for the
phonon modes are interpreted as due to caustics occurring in the geometrical acoustics approximation adopted in the computational
analysis. The results in LSCO and YBCO are found to be similar to those in BSCCO. 相似文献
5.
Jyoti Malviya R. K. P. Singh Shashi Kala L. K. Sharma 《Russian Journal of Electrochemistry》2018,54(3):311-317
A facile and Eco-compatible synthesis of benzofuran derivatives (4a–4h) has been carried out at platinum electrode by electrochemical oxidation of catechol in the presence of active methylene groups. Electro- organic synthesis has been performed in an undivided cell at ambient conditions. The products of electrolysis have been purified and characterized by FTIR, 1H NMR and 13C NMR and mechanism was deduced by voltammetric studies. 相似文献
6.
Comparative determinations of various phenothiazine derivatives in blood and urine samples were carried out using HPLC in reversed-phase mode and non-aqueous capillary electrophoresis (NACE). The examined samples of biological fluids originated from six forensic cases concerning poisonings with drugs, including the following commonly used phenothiazines: chlorpromazine, levomepromazine, promazine, and perazine. The quantification limits for both methods were similar and ranged from 0.02 to 0.35 µg mL?1. The correlation coefficient (r2) between the results obtained by two methods was 0.9869. 相似文献
7.
T. Kala 《Phase Transitions》2013,86(1-4):65-88
The theoretical backgrounds and some experimental data on the electronic properties of polycrystalline Pb(Zr, Ti)O3 solid solutions are summarized. These substances occur in the perovskite structure, and so their electronic band structure is presumed to be analogous to other perovskite compounds. Their forbidden gap energy has been determined to be about 3.30–3.56 eV on the basis of optical, photoacoustical, and photoelectrical measurements. Many local levels and traps exist in the forbidden gap because of the polycrystalline character and heterovalent doping. Their actual configurations and states strongly influence the optical, photoelectrical, piezoelectrical, and other physical properties of Pb(Zr, Ti)O3 solid solutions. 相似文献
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This article compares the solid phase extraction (SPE) and coprecipitative preconcentration of cadmium and lead from dilute aqueous solutions as a function of pH and weight of chelating agent. SPE enriches cadmium and lead over a wider pH range (6.0-8.0) and requires lower weight of DBQ chelate embedded benzophenone. Among the quinoline-8-ol and its dihaloderivatives, DBQ embedded benzophenone allows quantitative enrichment over a wide pH range (6.0-8.0) for both cadmium and lead unlike DCQ (∼6.5 for Cd and 6.5-7.0 for Pb), DBQ was preferred. The calibration plots were rectilinear over the concentration range of 0.1-50 and 2.5-200 μg l−1 of cadmium and lead with detection limits of 0.1 and 2.0 μg l−1, respectively, which are 400 times lower than the direct FAAS method. The precision of the developed procedure is good as it provides relative standard deviation values of 2.20 and 2.45% during five replicate determinations of 2 and 25 μg l−1 of cadmium and lead, respectively. The accuracy of the developed procedure was tested by analyzing certified reference materials (CRM's) of soil and marine sediment samples supplied by IAEA, Italy and NRC, Canada, respectively. Furthermore, the developed procedure has been successfully used for the speciative determination of cadmium and lead in soil samples collected from the vicinity of industries in India. 相似文献
10.
Let T=(T*, T?) be a spherical latin bitrade. With each a=(a1, a2, a3)∈T* associate a set of linear equations Eq(T, a) of the form b1+b2=b3, where b=(b1, b2, b3) runs through T*\{a}. Assume a1=0=a2 and a3=1. Then Eq(T,a) has in rational numbers a unique solution $b_{i}=\bar{b}_{i}Let T=(T*, T?) be a spherical latin bitrade. With each a=(a1, a2, a3)∈T* associate a set of linear equations Eq(T, a) of the form b1+b2=b3, where b=(b1, b2, b3) runs through T*\{a}. Assume a1=0=a2 and a3=1. Then Eq(T,a) has in rational numbers a unique solution $b_{i}=\bar{b}_{i}$. Suppose that $\bar{b}_{i}\not= \bar{c}_{i}$ for all b, c∈T* such that $\bar{b}_{i}\not= \bar{c}_{i}$ and i∈{1, 2, 3}. We prove that then T? can be interpreted as a dissection of an equilateral triangle. We also consider group modifications of latin bitrades and show that the methods for generating the dissections can be used for a proof that T* can be embedded into the operational table of a finite abelian group, for every spherical latin bitrade T. © 2009 Wiley Periodicals, Inc. J Combin Designs 18: 1–24, 2010 相似文献