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11.
Background
Pentachloronitrobenzene (PCNB) and hexachlorobenzene (HCB) are highly toxic and widespread in every environmental compartment. Some of metabolic products such as amino/nitro containing chlorinated aromatic compounds can be determined by gas chromatography coupled with electron capture detector (GC-ECD). However, it is difficult to identify some of chlorophenolic and chloroquinolic intermediates produced from PCNB and HCB by the above mentioned technique. Therefore, for analysis of these compounds and their metabolites, we have developed a high performance liquid chromatography (HPLC) based method.Results
The extraction of PCNB and HCB from soil and minimal salt medium was carried out with ethyl acetate and hexane respectively with good recoveries (98% for PCNB and 97% for HCB). The validation of the proposed extraction and HPLC method was done by analysis of PCNB and HCB biodegradation and their metabolites identification from anaerobic enriched soil samples.Conclusion
A rapid, sensitive and simple HPLC based analytical method was developed for the analysis of PCNB, HCB and their possible intermediates. 相似文献12.
Sasmal S Hazra S Kundu P Dutta S Rajaraman G Sañudo EC Mohanta S 《Inorganic chemistry》2011,50(15):7257-7267
This investigation presents the syntheses, crystal structures, magnetic properties, and density functional theoretical modeling of magnetic behavior of two heterobridged μ-phenoxo-μ(1,1)-azido dinickel(II) compounds [Ni(II)(2)(L(1))(2)(μ(1,1)-N(3))(N(3))(H(2)O)]·CH(3)CH(2)OH (1) and [Ni(II)(2)(L(2))(2)(μ(1,1)-N(3))(CH(3)CN)(H(2)O)](ClO(4))·H(2)O·CH(3)CN (2), where HL(1) and HL(2) are the [1+1] condensation products of 3-methoxysalicylaldehyde and 1-(2-aminoethyl)-piperidine (for HL(1))/4-(2-aminoethyl)-morpholine (for HL(2)), along with density functional theoretical magneto-structural correlations of μ-phenoxo-μ(1,1)-azido dinickel(II) systems. Compounds 1 and 2 crystallize in orthorhombic (space group Pbca) and monoclinic (space group P2(1)/c) systems, respectively. The coordination environments of both metal centers are distorted octahedral. The variable-temperature (2-300 K) magnetic susceptibilities at 0.7 T of both compounds have been measured. The interaction between the metal centers is moderately ferromagnetic; J = 16.6 cm(-1), g = 2.2, and D = -7.3 cm(-1) for 1 and J = 16.92 cm(-1), g = 2.2, and D(Ni1) = D(Ni2) = -6.41 cm(-1) for 2. Broken symmetry density functional calculations of exchange interaction have been performed on complexes 1 and 2 and provide a good numerical estimate of J values (15.8 cm(-1) for 1 and 15.35 cm(-1) for 2) compared to experiments. The role of Ni-N bond length asymmetry on the magnetic coupling has been noted by comparing the structures and J values of complexes 1 and 2 together with previously published dimers 3 (Eur. J. Inorg. Chem. 2009, 4982), 4 (Inorg. Chem. 2004, 43, 2427), and 5 (Dalton Trans. 2008, 6539). Our extensive DFT calculations reveal an important clue to the mechanism of coupling where the orientation of the magnetic orbitals seems to differ with asymmetry in the Ni-N bond lengths. This difference in orientation leads to a large change in the overlap integral between the magnetic orbitals and thus the magnetic coupling. DFT calculations have also been extended to develop several magneto-structural correlations in this type of complexes and the correlation aim to focus on the asymmetry of the Ni-N bond lengths reveal that the asymmetry plays a proactive role in governing the magnitude of the coupling. From a completely symmetric Ni-N bond length, two behaviors have been noted: with a decrease in bond length there is an increase in the ferromagnetic coupling, while an increase in the bond lengths leads to a decrease in ferromagnetic interaction. The later correlation is supported by experiments. The magnetic properties of 1, 2, and three previously reported related compounds have been discussed in light of the structural parameters and also in light of the theoretical correlations determined here. 相似文献
13.
We have analysed the two body non-leptonic charmed-meson decays of heavyB meson based on the factorization assumption. The transition matrix elements and the corresponding decay widths are calculated
in the heavy quark and chiral symmetry limit and the Isgur-Wise function present in the expression is determined by the wave
function model of Aliet al. The results obtained are quite interesting and agree reasonably well with the experimental data. 相似文献
14.
The weak radiative decay Λ
b
→Λγ is studied in the heavy quark effective theory treatings-quark as heavy. This rare decay is induced by the short distance electromagnetic penguins. Including corrections of the order
of (1/m
Q), we obtain the transition matrix element and the corresponding decay width. The Isgur-Wise function is evaluated in the
largeN
c limit and the branching ratio obtained is 1.48×10−5. 相似文献
15.
It is well known that the study of flavour physics and CP violation is very important to critically test the Standard Model
and to look for possible signature of new physics beyond it. The observation of CP violation in kaon system in 1964 has ignited
a lot of experimental and theoretical efforts to understand its origin and to look for CP violation effects in other systems
besides the neutral kaons. The two B-factories BABAR and BELLE, along with other experiments, in the last decade or so made studies in flavour physics and CP
violation a very interesting one. In this article we discuss the status and prospectives of the flavour physics associated
with the strange, charm and bottom sectors of the Standard Model. The important results in kaon sector will be briefly discussed.
Recently, mixing in the charm system has been observed, which was being pursued for quite some time without any success. The
smallness of the mixing parameters in the charm system is due to the hierarchical structure of the CKM matrix. Interestingly,
so far we have not found CP violation in the charm system but in the future, with more dedicated experiments at charm threshold,
the situation could change. Many interesting observations have been made in the case of bottom mesons and some of them show
some kind of deviations from that of the Standard Model expectations which are mainly associated with the b → s flavour changing neutral current transitions. It is long believed that the B
s
system could be the harbinger of new physics since it is a system in which both bottom and strange quarks are the constituents.
Recently, D0 and CDF announced their result for the B
s
mixing which is claimed to be the first possible new physics signature in the flavour sector. We plan to touch upon all important
issues pointing out both theoretical and experimental developments and future prospects in this review article. 相似文献
16.
17.
Electrical bistability and memory switching phenomenon in Cu2FeSnS4 thin films: role of p-n junction
Madhusudanan Sreejith P. Mohanta Kallol Batabyal Sudip K. 《Journal of Solid State Electrochemistry》2019,23(5):1307-1314
Journal of Solid State Electrochemistry - Electrical bistability of Cu2FeSnS4 (CFTS) thin films fabricated via successive ionic layer adsorption and reaction (SILAR) method was studied here. The... 相似文献
18.
We consider the thermoelastic plate under the presence of along range memory. We find uniform rates of decay (in time)of the energy, provided that suitable assumptions on the relaxationfunctions are given. Namely, if the relaxation decays exponentiallythen the first order energy also decays exponentially. Whenthe relaxation g satisfies -c1g(t)1+1/p g'(t) -cog(t)1+1/p; and g,g1-1/p L1 (R) withp > 2 then the energy decays as 1/(1+t)p. A new Liapunov functionalis built for this problem. 相似文献
19.
20.
Using integer and noninteger n-Slater type orbitals in single- and double-zeta approximations, the Hartree-Fock-Roothaan calculations were performed for the ground states of first ten cationic members of the isoelectronic series of He atom. All the noninteger parameters and orbital exponents were fully optimized. In the case of noninteger n-Slater type orbitals in double zeta basis sets, the results of calculations obtained are more close to the numerical Hatree-Fock values and the average deviations of our ground state energies do not exceed 2×10-6 hartrees of their numerical results. 相似文献