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1.
The equilibria for formation of iron(III) complexes with 1-hydroxy-7-sulpho-2-naphthoic and 1-hydroxy-4,7-disulpho-2-naphthoic acids in aqueous 0.1M sodium perchlorate medium at 25 degrees have been studied by spectrophotometric and potentiometric methods. The data are well described in terms of a series of stepwise complexes, FeL((3-rn)+)(r) in both systems (L(n-) denotes the unprotonated ligand anion). 相似文献
2.
Necessary and sufficient conditions are obtained for every solution of
to oscillate or tend to zero as n , where p
n, q
n and f
n are sequences of real numbers such that q
n 0. Different ranges for p
n are considered. 相似文献
3.
In this paper, sufficient conditions have been obtained under which every solution of
, oscillates or tends to zero or to ±∞ → ∞. Usually these conditions are stronger than
. An example is given to show that the condition (*) is not enough to arrive at the above conclusion. Existence of a positive
(or negative) solution of
is considered. 相似文献
4.
N. Parhi P. Das 《数学物理学报(B辑英文版)》1998,(1)
1IntroductionInthispaperwedealwithoscillatoryandnonoscillatorybehaviourofsolutionsofnonlinearthirdorderdifferentialequationsoftheformwherea,b,cEC([er,co),R),rrER,fEC(R,R)suchthatac2P>0fory/0and7>0isaquotientofoddintegers.From"Theoryofequations"tsee[1],itfollowsthattheequationwithconstantcoefficientsMoreover,allnonoscillatorysolutionsof(1.3)tendtozeroifandonlyifequatioll(l.3)hasanoscillatorysolution.Theseobservationsarefoundtobetruetoalargeextentformoregeneralequationsoftheformwherealb,cE… 相似文献
5.
A Liapunov-type inequality for a class of third order delay-differential equations is derived. 相似文献
6.
In this paper, the structure of the solution space of y n +3 + ry n +2 + qy n +1 + py n =0, n S 0, is studied, keeping oscillatory/nonoscillatory behaviour of solutions of the equation in view, where p , q and r are constants. Some of these results are generalized partially to hold for y n +3 + r n y n +2 + q n y n +1 + p n y n =0, n S 0, where { p n }, { q n } and { r n } are sequences of real numbers. 相似文献
7.
A solid-state metathesis approach for the synthesis of hydrated MnV2O6·xH2O (x=2, 4) materials driven by mechanochemical activation energy has been demonstrated. The metathesis pathway of forming the desired product is confirmed by the presence of high lattice energy by-product such as NaCl. The structural, optical, and chemical properties of the synthesized materials are examined by powder X-ray diffraction, X-ray photoelectron spectroscopy, thermo gravimetric analysis, scanning electron microscopy, transmission electron microscopy, and diffused reflectance measurements in the UV–vis range. The valence state of Mn and V was determined to be +2 and +5, respectively, for the title compounds and the bandgap values determined showed these materials are likely to be semiconductors. 相似文献
8.
Ajit K. Parhi 《Tetrahedron》2008,64(42):9821-9827
In this report the concept of converting carbohydrate to non-carbohydrate asymmetric molecules has been successfully exploited. The mixed acetal segment of glyceroplasmalopsychosine, a novel glycolipid, has been synthesized in a stereospecific manner using two simple sugar units. The glycosidation reaction between these two monosaccharides ensured the correct acetal stereocenter of the target molecule. Either olefin metathesis or heterogeneous Wittig reactions were used for constructing the long aliphatic chain of glyceroplasmalopsychosine. 相似文献
9.
Ajit K. Parhi 《Tetrahedron letters》2008,49(21):3395-3399
Three fluorescent probes were synthesized aiming for optical imaging to detect amyloid plaques present in the patients with Alzheimer’s disease (AD). These compounds were prepared via Sonogashira coupling of a well-defined fluorophore (4-bora-3a,4a-diaza-s-indacene, BODIPY) with the pharmacophore possessing either a stilbene or a diphenylacetylene moiety. Different polyethylene glycol chain lengths were used as linkers between the fluorophore and the pharmacophore to adjust the lipophilicity of these probes. These compounds exhibit strong fluorescence emission between 665 and 680 nm and have very high extinction coefficients comparable to the parent fluorophore, BODIPY dye. 相似文献
10.
The current research work has employed an evolutionary based novel navigational strategy to trace the collision free near optimal path for underwater robot in a three-dimensional scenario. The population based harmony search algorithm has been dynamically adapted and used to search next global best pose for underwater robot while obstacle is identified near about robot’s current pose. Each pose is evaluated based on their respective value for objective function which incorporates features of path length minimization as well as obstacle avoidance. Dynamic adaptation of control parameters and new perturbation schemes for solution vectors of harmony search has been proposed to strengthen both exploitation and randomization ability of present search process in a balanced manner. Such adaptive tuning process has found to be more effective for avoiding early convergence during underwater motion in comparison with performances of other popular variants of Harmony Search. The proposed path planning method has also shown better navigational performance in comparison with improved version of ant colony optimization and heuristic potential field method for avoiding static obstacles of different shape and sizes during underwater motion. Simulation studies and corresponding experimental verification for three-dimensional navigation are performed to check the accuracy, robustness and efficiency of proposed dynamically adaptive harmony search algorithm. 相似文献