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1.
Journal of Thermal Analysis and Calorimetry - In the case of flow boiling, the prediction of vapour fraction in the horizontal microchannel is a severe issue using the numerical technique.... 相似文献
2.
Pavan Mathur 《Journal of Chemical Sciences》2006,118(6):553-568
New tetradentatebis-benzimidazole ligands have been synthesized and utilized to prepare copper (II) complexes. Some of these copper (II) complexes
have been characterized structurally. The copper (II) in these complexes is found to possess varying geometries. A distorted
octahedral geometry is found with a highly unsymmetrical bidentate nitrate group. An unusual polymeric one-dimensional structure
is observed where copper (II) is in a distorted square pyramidal geometry with a monodentate nitrate ion, having long Cu-O
bond, while a distorted triagonal bipyramidal geometry is found with two carbonyl O atoms and a Cl atom in the equatorial
plane, and two benzimidazole imine N atoms occupy the axial position. These compounds are found to activate the cumylperoxyl
group, and this has been utilized in the facile oxidation of aromatic alcohols to aldehydes, where they act as catalysts with
large turnovers. The yields of the respective products vary from 32 to 65%. The role of molecular oxygen has been studied
and an attempt has been made to identify the “active copper species”. Activation of molecular oxygen has also been observed
and has been used for oxidative dealkylation of a hindered phenol, producing di-butyl quinones with yields of 20–25% and 10–12
fold catalytic turnover. Dihydroxybenzenes and substituted catechols are also readily oxidized to the corresponding quinones,
in oxygen-saturated solvents. Yields of 84% have been observed with 34-fold catalyst turnover, with di-t-butylcatechol. The activity of these copper (II) —bis-benzmidazolediamide compounds is reminiscent of the functioning of copper centres in galactose oxidase, tyrosinase and catechol
oxidase. 相似文献
3.
We report the results of a study of white light generation in a 7.5 cm long crystal of a high band-gap material, barium fluoride, using ultrashort (<42 fs) laser pulses over a range of values of incident laser power that extend up to more than three orders of magnitude larger than the critical power for self-focusing (Pcr). We explore white light generation and the intensity and spectral distributions within filaments that are formed as a result of the interplay of self-focusing and plasma-induced defocusing. The onset of plasma effects occurs at power levels in excess of 7 GW for ultrashort pulses in BaF2. For incident power levels that are three orders of magnitude larger than the critical power, blue-shifting of the incident laser wavelength is observed in addition to asymmetric continuum generation. The blue shift enables us to estimate the temporal variation of the electron density in the plasma that is generated within the BaF2 crystal. PACS 52.38.Hb; 42.65.Jx; 42.65.Tg; 33.80.Wz; 52.35.Mw 相似文献
4.
V Ravindran Pankaj Agrawal Rahul Basu Satyaki Bhattacharya J Blümlein V Del Duca R Harlander D Kosower Prakash Mathews Anurag Tripathi 《Pramana》2006,67(5):983-992
This is the report of the subgroup QCD of Working Group-4 at WHEPP-9. We present the activities that had taken place in the
subgroup and report some of the partial results arrived at following the discussion at the working group meetings. 相似文献
5.
Pankaj Mathur 《分析论及其应用》2006,22(2):105-113
In this paper, we study the explicit representation and convergence of (0, 1;0)-interpolation on infisite interval, which means to determine a polynomial of degree ≤ 3n - 2 when the function values areprescribed at two set of points namely the zeros of Hn(x) and H′n (x) and the first derivatives at the zerosof H′n(x). 相似文献
6.
It has been found that the states of the 2-charge extremal D1–D5 system are given by smooth geometries that have no singularity and no horizon individually, but a ‘horizon’ does arise after ‘coarse-graining’. To see how this concept extends to the 3-charge extremal system, we construct a perturbation on the D1–D5 geometry that carries one unit of momentum charge P. The perturbation is found to be regular everywhere and normalizable, so we conclude that at least this state of the 3-charge system behaves like the 2-charge states. The solution is constructed by matching (to several orders) solutions in the inner and outer regions of the geometry. We conjecture the general form of ‘hair’ expected for the 3-charge system, and the nature of the interior of black holes in general. 相似文献
7.
In this paper we study the pollution-error in the h-version of the finite element method and its effect on the local quality of a-posteriori error estimators. We show that the pollution-effect in an interior subdomain depends on the relationship between the mesh inside and outside the subdomain and the smoothness of the exact solution. We also demonstrate that it is possible to guarantee the quality of local error estimators in any mesh-patch in the interior of a finite-element mesh by employing meshes which are sufficiently refined outside the patch. 相似文献
8.
Pankaj K. Agarwal 《Discrete and Computational Geometry》1990,5(1):533-573
In this paper we present efficient deterministic algorithms for various problems involving lines or segments in the plane, using the partitioning algorithm described in a companion paper [A3]. These applications include: (i) anO(m
2/3
n
2/3 · log2/3
n · log/3 (m/n)+(m+n) logn) algorithm to compute all incidences betweenm points andn lines, where is a constant <3.33; (ii) anO(m
2/3
n
2/3 · log5/3
n · log/3 (m/n)+(m+n) logn) algorithm to computem faces in an arrangement ofn lines; (iii) anO(n
4/3 log(+2)/3
n) algorithm to count the number of intersections in a set ofn segments; (iv) anO(n
4/3 log( + 2)/3
n) algorithm to count red-blue intersections between two sets of segments, and (v) anO(n
3/2 log/3
n) algorithm to compute spanning trees with low stabbing number for a set ofn points. We also present an algorithm that, given set ofn points in the plane, preprocesses it, in timeO(nm log+1/2
n), into a data structure of sizeO(m) forn lognmn
2, so that the number of points ofS lying inside a query triangle can be computed inO((n/m) log3/2
n) time.Work on this paper has been supported by Office of Naval Research Grant N00014-87-K-0129, by National Science Foundation Grant DCR-83-20085, and by grants from the Digital Equipment Corporation and the IBM Corporation. A preliminary version of this paper appears in theProceedings of the 5th ACM Symposium on Computational Geometry, 1989, pp. 11–22. 相似文献
9.
The electrochemical oxidation of ethyl 3-oxo-3-phenyl-2-phenylhydrazonopropionate has been studied in the pH range 3.0–11.0 at a pyrolytic graphite electrode by linear and cyclic sweep voltammetry, coulometry and spectral studies. The results indicate that the 2 e−, 2 H+ oxidation of this compound gives phenol and ethyl 3-phenyl-2,3-dioxopropionate as the major products of electrooxidation. 相似文献
10.
S. C. Gupta B. B. Tak N. K. Mathur C. K. Narang 《Journal of Radioanalytical and Nuclear Chemistry》1993,170(1):3-8
Polyamino group-containing resins act both as chelating ion exchangers and weakly basic anion exchangers depending upon the species in contact in the solution. In the present work, ion exchangers based on polyamine incorporated polysaccharides (cellulose and galactomannan or guaran) have been used for removal of radioisotopes of185W as WO
4
2–
,99Mo as MoO
4
2–
and125Sb as Sb3+ from their separate aqueous solutions. These chelating anion exchangers have been synthesized by reaction of polysaccharides with epichlorohydrin followed by the respective polyamines as nucleophiles in a strongly alkaline medium. WO
4
2–
and MoO
4
2–
are adsorbed from their aqueous solutions through anion exchange process by chloride form of cellulose-triethylenetetraamine (cellulose-trien), cellulose-tetraethylenepentaamine (cellulose-tetren), guaran-triethylenetetraamine (guar-trien) and guar-tetraethylenepentaamine (guar-tetren) weakly basic anion exchangers. Guar-tetren chelating polymer has been found to be highly selective for125Sb isotopes presumably due to the presence of chelating cis-hydroxy and tetren groups in the galactomannan matrix. 相似文献