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Kanchi Suvardhan Kailasa Suresh Kumar Dasari Rekha Pantrangam Subrahmanyam Kapuvedi Kiran Bellum Jayaraj Surasura Ramanaiah Kandhukuri Janardhanam Pattium Chiranjeevi 《Mikrochimica acta》2007,157(3-4):237-244
Cloud point extraction was applied as a method for preconcentration of rhodium after formation of a complex with 2-propylpiperidine-1-carbodithioate
(2-PPC), and later determined by flame atomic absorption spectrometry using TritonX-114 as surfactant. Rhodium was complexed
with 2-PPC in an aqueous phase and kept for 15 min in a thermostatted bath at 40 °C. Separation of the two phases was accomplished
by centrifugation for 15 min at 4000 rpm. The chemical variables affecting the cloud point extraction were optimized and successfully
applied to rhodium determination in various water samples. Under optimized conditions, the preconcentration system (100 mL
sample) permitted an enhancement factor of 50. The detection limits obtained under optimal conditions was 0.052 ng mL−1. The extraction efficiency was investigated at different rhodium concentrations (7.0–42.0 μg mL−1), and good recoveries (96.42–99.14%) were obtained using this method. It has been applied to the determination of rhodium
in water and was compared with reported methods in terms of Student’s ‘t’-test and variance ratio ‘f’-test. 相似文献
2.
The optical absorption spectrum of Ni2+ ion doped in ammonium zinc sulphate has been studied at room and liquid air temperatures. From the nature and the positions
of the bands a successful interpretation of all the bands could be made assumingO
h
symmetry for the Ni2+ ion in the crystal. The fine splitting of the3
T
1
1 band at liquid air temperature has been successfully interpreted to be due to spin-orbit interaction. The crystal field and
spin-orbit parameters derived areDq=1000 cm−1;B=750 cm−1;C=3.45B andξ=600 cm−1. 相似文献
3.
B. Prasanna Lakshmi V. Rajagopal Reddy V. Janardhanam M. Siva Pratap Reddy Jung-Hee Lee 《Applied Physics A: Materials Science & Processing》2013,113(3):713-722
We report on the effect of an annealing temperature on the electrical properties of Au/Ta2O5/n-GaN metal–insulator–semiconductor (MIS) structure by current–voltage (I–V) and capacitance–voltage (C–V) measurements. The measured Schottky barrier height (Φ bo) and ideality factor n values of the as-deposited Au/Ta2O5/n-GaN MIS structure are 0.93 eV (I–V) and 1.19. The barrier height (BH) increases to 1.03 eV and ideality factor decreases to 1.13 upon annealing at 500 °C for 1 min under nitrogen ambient. When the contact is annealed at 600 °C, the barrier height decreases and the ideality factor increases to 0.99 eV and 1.15. The barrier heights obtained from the C–V measurements are higher than those obtained from I–V measurements, and this indicates the existence of spatial inhomogeneity at the interface. Cheung’s functions are also used to calculate the barrier height (Φ bo), ideality factor (n), and series resistance (R s ) of the Au/Ta2O5/n-GaN MIS structure. Investigations reveal that the Schottky emission is the dominant mechanism and the Poole–Frenkel emission occurs only in the high voltage region. The energy distribution of interface states is determined from the forward bias I–V characteristics by taking into account the bias dependence of the effective barrier height. It is observed that the density value of interface states for the annealed samples with interfacial layer is lower than that of the density value of interface states of the as-deposited sample. 相似文献
4.
From optical absorption studies at room and liquid air temperatures and from Mössbauer spectrum, the absorption bands of spessartine garnet are attributed to Mn2+ and Fe2+ ions. The energy matrices ofd 5 andd 6 configurations are solved and the experimental data of Mn2+ and Fe2+ bands are fitted with the calculated values to solve for the Racah and crystal field parameters. 相似文献
5.
A tricyclic intermediate with the potentials to be elaborated to a A-ring aromatic or non-aromatic steroid system, bearing a methyl at C8 carbon, has been synthesized via an oxy-Cope rearrangement from the readily available α-tetralone. 相似文献
6.
S. V. J. Lakshman B. J. Reddy K. Janardhanam V. L. R. Murthy P. Rama Devi 《Czechoslovak Journal of Physics》1978,28(10):1122-1124
The electronic absorption spectrum of chrysocolla, a silicate mineral of copper, has been studied at room and liquid air temperatures. The observed bands were satisfactorily explained as belonging to Cu2+ ion subjected to tetragonal and spin-orbit fields. A good fit between the theoretical and observed band positions was obtained for the following crystal field parameters:Dq=–1400 cm–1
Ds=–3000 cm–1
Dt=–800 cm–1
=–800 cm–1 相似文献
7.
S. Janardhanam A. Balakumar K. Rajagopalan L. Suganthi Bai K. Ravikumar S. S. Rajan 《合成通讯》2013,43(3):297-310
A rational synthesis of Spiro bicyclo (5,4) dec-2-ene-3-methyl-1,6-dione (1) and Spiro bicyclo (5,5) undec-2-ene-3-methyl-1,7-dione (2) from 2-acetyl cycloalkanone is described. Compounds (1) and (2) have very high potentials as important precursors to many naturally occurring bridged tricyclic compounds. A single crystal X-ray crystallographic study of compound (2) was carried out to establish the structure as chemical and spectral methods proved rather inadequate. 相似文献
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