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101.
Parida KM Mallick S Mohapatra BK Misra VN 《Journal of colloid and interface science》2004,277(1):48-54
Physicochemical characterization of manganese-nodule leached residues was carried out by chemical analyses, XRD, TG-DTA, surface area measurement, and FTIR techniques. The material is very fine-grained (<75 microm), is cryptocrystalline to amorphous in nature, and contains mainly of delta-MnO(2), quartz (alpha-SiO(2)), and zeolite/feldspar minerals. Physically adsorbed sulfates in the leached residue are removed by repeated water washing and the washed sample shows an appreciable increase in surface area. This is indicated by the absence of 1387 and 1099 cm(-1) peaks in the IR spectrum of the washed sample. The adsorption behavior of the washed sample toward Ni(2+) was recorded as a function of time, pH, temperature, and concentrations of adsorbent and adsorbate. 相似文献
102.
103.
Misra SK Andronenko SI Rinaldi G Chand P Earle KA Freed JH 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2003,160(2):131-138
Multifrequency electron paramagnetic resonance studies on the Mn(2+) impurity ion in a mixed single crystal NH(4)Cl(0.9)I(0.1) were carried out at 9.62 (X-band) in the range 120-295 K, at 35.87 (Q-band) at 77 and 295 K, and at 249.9 GHz (far-infrared band) at 253 K. The high-field EPR spectra at 249.9 GHz are well into the high-field limit leading to a considerable simplification of the spectra and their interpretation. Three magnetically inequivalent, but physically equivalent, Mn(2+) ions with their respective magnetic Z-axes oriented along the crystallographic [100], [010], [001] axes were observed. Simultaneous fitting of EPR line positions observed at X-, Q-, and far infra-red bands was performed using a least-squares procedure and matrix diagonalization to estimate accurately the Mn(2+) spin-Hamiltonian parameters. The temperature variation of the linewidth and peak-to-peak intensities of the EPR lines indicate the presence of lambda-transitions in the mixed NH(4)Cl(0.9)I(0.1) crystal at 242 and 228 K consistent with those observed in the pure NH(4)Cl and NH(4)I crystals, respectively. A superposition-model analysis of the spin-Hamiltonian parameters reveals that the local environment of the Mn(2+) ion is considerably reorganized to produce axially symmetric crystal fields about the respective Z-axes of the three magnetically inequivalent ions as a consequence of the vacancy created due to charge-compensation when the divalent Mn(2+) ion substitutes for a monovalent NH(4)(+) ion in the NH(4)Cl(0.9)I(0.1) crystal. This reorganization is almost the same as that observed in NH(4)Cl and NH(4)I single crystals, although the latter two are characterized by different, simple cubic and face-centered cubic, structures. 相似文献
104.
Ronald G.?DouglasEmail author Gadadhar?Misra 《Integral Equations and Operator Theory》2003,47(4):435-456
The notion of a quasi-free Hilbert module over a function algebra
$\mathcal{A}$ consisting of holomorphic functions on a bounded domain $\Omega$ in complex m
space is introduced. It is shown that quasi-free Hilbert modules correspond to
the completion of the direct sum of a certain number of copies of the algebra
$\mathcal{A}$. A Hilbert module is said to be weakly regular (respectively, regular) if there
exists a module map from a quasi-free module with dense range (respectively,
onto). A Hilbert module $\mathcal{M}$ is said to be compactly supported if there exists a
constant $\beta$ satisfying $\|\varphi f\| \leq \beta \ |\varphi \| \textsl{X} \|f \|$ for some compact subset X of $\Omega$ and
$\varphi$ in $\mathcal{A}$, f in $\mathcal{M}$. It is shown that if a Hilbert module is compactly supported
then it is weakly regular. The paper identifies several other classes of Hilbert
modules which are weakly regular. In addition, this result is extended to yield
topologically exact resolutions of such modules by quasi-free ones. 相似文献
105.
BRST resolution is studied for the principally graded Wakimoto module of
recently found in math.QA/0005203. The submodule structure is completely determined and irreducible representations can be obtained as the zero-th cohomology group. 相似文献
106.
A complete normal coordinate analysis was performed for five-coordinate non-rigid triarylantimony diester SbPh3(O2CR)2, known to be a bioactive molecule, using Wilson G-F matrix method and Urey Bradley force field. The study of vibrational
dynamics was performed using the concept of group frequencies and band intensities.
相似文献
107.
High power continuous wave operation of a diode face-pumped thin Nd:YAG slab laser is reported. A novel pumping geometry for
a thin Nd:YAG slab using cylindrical lens duct coupled diode laser stacks is demonstrated. In a close-coupled resonator, a
maximum laser output power of 260 W in multimode operation is obtained. This corresponds to a slope efficiency of 34% and
an optical-to-optical efficiency of 27%, respectively. In high-brightness operation, a polarized laser output of 70 W has
been obtained with a beam quality factor close to 4 in both directions. The polarization contrast ratio is >100.
PACS 42.55.Xi; 42.60.Pk; 42.60.By 相似文献
108.
Priyanka Trivedi Jonnala Kotesh Kumar Arvind Singh Negi Karuna Shanker 《Biomedical chromatography : BMC》2011,25(6):697-706
Extraction and pre‐concentration of a bioactive marker compound, phenyl‐1,3,5‐heptatriyne from Bidens pilosa, prior to HPLC has been demonstrated using both organic and ecofriendly solvents. Non‐ionic surfactants, viz. Triton X‐100, Triton X‐114 and Genapol X‐80, were used for extraction. No back‐extraction or liquid chromatographic steps were required to remove the target phytochemical from the surfactant‐rich extractant phase. The optimized cloud point extraction procedure has been shown to be a potentially useful methodology for the preconcentration of the target analyte, with a preconcentration factor of 4–99. Moreover, the method is simple, sensitive, rapid and consumes lesser solvent than traditional methods. An isocratic chromatographic separation and quantitation was accomplished on a C18 column with acetonitrile–acidified aqueous as mobile phase at a flow rate of 1.0 mL/min, UV detection at 254 nm and specificity with photo diode‐array detector (PDA) and MS. Under the optimum experimental conditions recovery was satisfactory (99.18–100.33%) without interference from the surfactant. The method seems to be reliable with intraday precision and interday precision below 2.0%. Good linearity was obtained in the working range from 7.5 to 30 µg/mL with correlation coefficient >0.99. The limits of detection and quantitation were 1.84 and 6.13 µg/mL, respectively. The method was validated following international guidelines and successfully applied for quantitative assays of cytotoxic compound phenyl‐1,3,5‐heptatriyne in Bidens pilosa. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
109.
Nonlinear ion-acoustic solitary waves in an electron-positron-ion plasma with relativistic positron beam
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The propagation characteristics of nonlinear ion–acoustic(IA) solitary waves(SWs) are studied in thermal electron–positron–ion plasma considering the effect of relativistic positron beam. Starting from a set of fluid equations and using the reductive perturbation technique, we derive a Korteweg–de Vries(KdV) equation which governs the evolution of weakly nonlinear IA SWs in relativistic beam driven plasmas. The properties of the IA soliton are studied, and it is shown that the presence of relativistic positron beam significantly modifies the characteristics of IA solitons. 相似文献
110.
Mazaahir Kidwai Preeti Misra Bhavesh Dave Kumar R. Bhushan Rajendra K. Saxena Meena Singh 《Monatshefte für Chemie / Chemical Monthly》2000,17(3):1207-1212
A novel synthesis of 6-fluoro-7-(5-aryl-1,3,4-thiadiazol/oxadiazol-2-yl-sulfanyl)-4-quinolone-3-carboxylic acids from 7-chloro-6-fluoro-4-quinolone-3-carboxylic acid and 5-substituted 1,3,4-thiadiazoles/oxadiazoles on basic alumina under microwave activation is described. All compounds were screened for their in vitro antibacterial activity against B. lichenformis, 2689, K. aerogens 2281, S. typhimurium 2501, E. herbicola 2491, and P. vulgaris 2027 and found to possess activities comparable to that of the standard drug norfloxacin. 相似文献