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排序方式: 共有165条查询结果,搜索用时 15 毫秒
41.
Determination of hexavalent chromium by on-line dialysis ion chromatography in a matrix of strong colourants and trivalent chromium 总被引:3,自引:0,他引:3
Ganeshjeevan R Chandrasekar R Yuvaraj S Radhakrishnan G 《Journal of chromatography. A》2003,988(1):151-159
Hexavalent chromium detection in the presence of a high load of colourants without any false positive and in-procedure oxidation of Cr(III) is an important area of study. Colourants are a class of interfering substances in many spectroscopic analyses and chromatographic separations and detection. A purification method using an on-line dialysis technique for ion chromatography (IC) has been developed to remove water-soluble anionic dyes and particulate colourants and other substances to facilitate Cr(VI) quantification and the method is discussed. The dialysis was optimized with Cr(VI) standard solutions for quantification. The efficacy of the procedure for the removal of anionic dyes and detection of Cr(VI) was checked with a Cr(VI) spiked synthetic preparation containing a water-soluble dye and trivalent chromium. Soluble Cr(VI) extracted with organic dyes from environmental samples was analyzed. The method has a detection limit of 5 microg/l, recovery rate of 100% and analysis time less than 20 min. 相似文献
42.
M. Lakshmanan V. K. Chandrasekar 《The European physical journal. Special topics》2013,222(3-4):665-688
In this article, we present a brief overview of some of the recent progress made in identifying and generating finite dimensional integrable nonlinear dynamical systems, exhibiting interesting oscillatory and other solution properties, including quantum aspects. Particularly we concentrate on Lienard type nonlinear oscillators and their generalizations and coupled versions. Specific systems include Mathews-Lakshmanan oscillators, modified Emden equations, isochronous oscillators and generalizations. Nonstandard Lagrangian and Hamiltonian formulations of some of these systems are also briefly touched upon. Nonlocal transformations and linearization aspects are also discussed. 相似文献
43.
Gowthaman I. Sathiyadevi K. Chandrasekar V. K. Senthilkumar D. V. 《Nonlinear dynamics》2020,101(1):53-64
Nonlinear Dynamics - Aging transition refers to the manifestation of the homogeneous steady state beyond a critical ratio of the inactive oscillators in a network of active and inactive... 相似文献
44.
Using the matrix method, spin-dependent tunneling properties such as barrier transparency, the degree of resonance polarization, and tunneling lifetime of electrons are examined in the non-magnetic/diluted magnetic semiconductor heterostructure. The effects of the double δ-potential and the magnetic field are discussed on the transport properties of the electrons. The introduction of double δ-potential shifts the resonance peak of polarization to the higher energy value. Both height and position of the δ-potential influence the degree of resonance polarization in the considered heterostructure. The increasing magnetic field enhances the spin-polarization. 相似文献
45.
S. Chandrasekar K. Panchanatheswaran 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):1442-1443
The identity of the title complex, C13H10ClNO·C7H6O2, is confirmed to be a hydrogen‐bonded adduct of benzoic acid and N‐(3‐chlorophenyl)‐α‐phenylnitrone. The two aromatic rings in the nitrone are trans about the C=N bond. 相似文献
46.
S. C. Sahoo N. Venkataramani Shiva Prasad Murtaza Bohra R. Krishnan 《Applied Physics A: Materials Science & Processing》2010,99(4):889-894
Co-ferrite thin films were prepared by pulsed laser deposition technique at room temperature, and magnetization was studied
as a function of annealing temperature (T
A
) and annealing time. One set of films was quenched immediately after annealing while the other set was furnace cooled. Spontaneous
magnetization value, 4π
M
S
, of the quenched films was observed to be higher than the furnace cooled films in all the cases. Magnetization increases
monotonically up to T
A
=650°C and then became nearly constant with the increase in T
A
. Magnetization values even higher than the Co-ferrite bulk value of 5300 G was observed in the quenched films annealed at
and above 650°C. In the case of furnace cooled films, magnetization decreased with the increase in annealing time, while it
remained nearly constant in quenched films. Coercivity values of the quenched films were always found to be lower than those
of the furnace cooled films. The observed magnetic properties in the films were attributed to the cation distribution and
the grain sizes. 相似文献
47.
Chandrasekar M. S. Shanmugasigamani Srinivasan Malathy Pushpavanam 《Journal of Solid State Electrochemistry》2009,13(5):781-789
Zinc–cobalt (Zn–Co) and zinc–nickel (Zn–Ni) alloy electrodeposits each prepared from acid and alkaline formulations were compared
for their properties. Compared to alkaline baths, acid baths offer higher metal percent of the alloying element and higher
current efficiency. In alkaline baths, the variation of metal percent in deposit with current density is less significant,
but that of current efficiency with current density is more. Electrolyte pH does not change significantly in alkaline solutions
compared to acid solutions. X-ray diffraction evaluation of Zn–Co deposits from both electrolytes indicated their presence
in the η-phase, while Zn–Ni shows pure γ-phase for deposits obtained from alkaline solutions and the existence of γ-phase
with traces of η-phase of zinc for deposits obtained from the acid electrolytes. Scanning electron microscope examination
shows finer grain structure for deposits obtained from alkaline solutions, and atomic force microscope studies confirm their
nanostructure with reduced surface roughness. Deposits obtained from the alkaline baths exhibited higher corrosion resistance
probably due to their nanostructure. 相似文献
48.
Nirmala C Trivedi R Prasanthi PV Mullangi R Srinivas NR 《Biomedical chromatography : BMC》2006,20(9):945-950
Grastim is bacterially produced recombinant counterpart of human granulocyte colony stimulating factor (G-CSF). It has biological activity similar to that of endogenous G-CSF. In the present work a sensitive, accurate, precise and enzyme-linked immunosorbent assay (ELISA) for the quantitation of G-CSF in rat plasma was developed and validated. The ELISA method employed a technique in which anti-human-G-CSF was adsorbed onto 96-well maxisorp plates and used to capture the G-CSF in rat plasma samples. The captured G-CSF was then detected using streptavidin-HRP amplification system. Absolute recovery was >90% from rat plasma. The validation includes assessments of method accuracy and precision, range of reliable response, lower limit of quantitation (LLOQ), storage stability (30 days) in rat plasma and assay specificity. The standard curve for G-CSF was linear (R2 > 0.996) in the concentration range 4.88-625 pg/mL. The LLOQ was established at 4.88 pg/mL. The inter- and intra-day precisions in the measurement of quality control (QC) samples, 15, 250 and 500 pg/mL, were in the range 3.00-8.66% relative standard deviation (RSD) and 1.03-4.69% RSD, respectively. Accuracy in the measurement of QC samples was in the range 87.28-110.79% of the nominal values. The assay shows dilutional linearity and specificity. Stability of G-CSF was established for 30 days at -80 degrees C and through three freeze-thaw cycles. The validated assay was successfully employed for the assessment of pharmacokinetic disposition of G-CSF in rats. 相似文献
49.
Rajadurai C Schramm F Brink S Fuhr O Ghafari M Kruk R Ruben M 《Inorganic chemistry》2006,45(25):10019-10021
A one-dimensional supramolecular head-to-tail N+ -H...N-type hydrogen-bonded chain of the complex [FeII(L)2H](ClO4)3.MeOH [L = 4'-(4'-pyridyl)-1,2':6'1'-bis(pyrazolyl)pyridine] exhibits a reversible, thermally driven spin transition at 286 K with a hysteresis loop of ca. 2 K. 相似文献
50.