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21.
Sumanta Chakraborty Soumitra SenGupta 《The European Physical Journal C - Particles and Fields》2017,77(8):573
We show that a possible resolution to the stabilization of an extra spatial dimension (radion) can be obtained solely in the context of gravitational dynamics itself without the necessity of introducing any external stabilizing field. In this scenario the stabilized value of the radion field gets determined in terms of the parameters appearing in the higher curvature gravitational action. Furthermore, the mass of the radion field and its coupling to the standard model fields are found to be in the weak scale implying possible signatures in the TeV scale colliders. Some resulting implications are also discussed. 相似文献
22.
Indranil SenGupta 《Journal of Mathematical Analysis and Applications》2011,375(2):762-776
In this paper three-dimensional superradiance problem is considered and a differential operator that commutes with the integral operator related to the problem is obtained. All the eigenfunctions of the differential operator are found and a complete set of eigensolutions for the three-dimensional superradiance problem is obtained. 相似文献
23.
Amarendra Patra Sumana Ghosh Biswapati Mukherjee 《Magnetic resonance in chemistry : MRC》2010,48(10):823-828
Besides three known biphenyldibenzodioxinbisbenzylisoquinoline alkaloids, two novel alkaloids of the same group have been isolated from the fruits of Tiliacora racemosa. The structures of these new compounds designated tiliaimine and nordinklacorine were established on the basis of 1D and 2D NMR spectroscopy, including COSY, TOCSY, ROESY, HMBC and HSQC experiments. Preliminary antibacterial activity studies on the known compounds (tiliarine, 2′‐nortiliacorinine, 2′‐nortiliacorine) from the fruits of the plant showed strong activity against three bacterial strains viz. Escherichia coli strain VT3 (Verotoxigenic E.coli), Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6623 but were inactive against the strains Vibrio cholerae O1 (NB2) and Pseudomonas aeruginosa ATCC 15442. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Tetrahydropyran (THP) undergoes photodissociation on excitation with ArF laser at 193 nm, generating OH radical as one of the transient photoproducts. Laser-induced fluorescence technique is used to detect the nascent OH radical and measure its energy state distribution. The OH radical is formed mostly in the ground vibrational level (v"=0), with low rotational excitation. The rotational distribution of OH (v"=0,J) is characterized by a temperature of 433+/-31 K, corresponding to a rotational energy of 0.86+/-0.06 kcalmol. Two Lambda-doublet levels, 2Pi+(A') and 2Pi-(A"), and the two spin-orbit states, the 2Pi(3/2) and 2Pi(1/2), of OH are populated statistically for all rotational levels. The relative translational energy associated with the photoproducts in the OH channel is calculated to be 21.9+/-3.2 kcal mol(-1), from the Doppler-broadened linewidth, giving an ft value of approximately 43%, and most of the remaining 57% of the available energy is distributed in the internal modes of the other photofragment, C5H9. The observed distribution of the available energy is explained well, using a hybrid model of energy partitioning, with an exit barrier of 40 kcal mol(-1). The potential-energy surface of the reaction channel was mapped by ab initio molecular-orbital calculations. Based on experimental and theoretical results, a mechanism for OH formation is proposed. Electronically excited THP relaxes to the ground electronic state, and from there, a sequence of reactions takes place, generating OH. The proposed mechanism first involves C-O bond scission, followed by a 1,3 H atom migration to O atom, and finally, the C-OH bond cleavage giving OH. 相似文献
25.
Rahul Bhattacharya Sumana Chanda Andrea Cantoni Gabriele Bocelli Ashutosh Ghosh 《Journal of chemical crystallography》2004,34(5):325-331
The crystal structures of benzimidazolium tetrahalocobaltates (HBz)2[CoX4] (X = Cl and Br) have been determined. The chloride salt is triclinic, P-1, with a = 7.670(3) Å, b = 8.307(3) Å, c = 15.730(2) Å, and = 87.37(3)°, = 84.99(3)°, = 67.72(2)°. The bromide salt is monoclinic, C2/c, with a = 15.568(2) Å, b = 8.063(3) Å, c = 5.762(2) Å and = 91.36(3)°. The structures of the two salts are closely related. Both the compounds contain isolated tetrahedral CoX4
2– anions and benzimidazolium cations. In the chloride salt, three chloride ions are involved in strong hydrogen bonding while only two bromide ions participate in the bromide salt. The greater deviation from the ideal tetrahedral geometry in CoBr4
2– can be related to the less extensive hydrogen-bonding network compared to the chloro complex. 相似文献
26.
The iron(II) complex of H2L (H2L=3, 14‐dimethyl‐4, 7, 10, 13‐tetraazahexadeca‐3,13‐diene‐2,15‐dione dioxime, Coord. Chem. Rev., 33, 87 (1980)) is oxidized by periodate very rapidly in the range pH 2.0–7.0, and the kinetics of the reaction has been followed by stopped‐flow spectrophotometry at 30°C and ionic strength I=0.20 mol L−1 (NaClO4). The reaction is found to follow a simple second‐order kinetics as −d/dt [FeII(H2L)2+]=k [FeII(H2L)2+] [I(VII)], giving [FeIII(L)]+ and IO3− as the final products. The reaction has been proposed to occur through a H‐bonded transition state formed probably between the protonated oxime group of the ligand and the oxygen atom on the periodate species, followed by an electron transfer from FeII centre to IVII in a rate‐determining step. The IVI species thus generated reacts in a fast step with another FeII complex. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 23–28, 1999 相似文献
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B.?MukhopadhyayaEmail author S.?Sen S.?SenGupta S.?Sur 《The European Physical Journal C - Particles and Fields》2004,35(1):129-135
The possibility of parity violation in a gravitational theory with torsion is extensively explored in four and higher dimensions. In the former case, we have listed our conclusions on when and whether parity ceases to be conserved, with both two- and three-index antisymmetry of the torsion field. In the latter, the bulk spacetime is assumed to have torsion, and the survival of parity violating terms in the four dimensional effective action is studied, using the compactification schemes proposed by Arkani-Hamed-Dimopoulos-Dvali and Randall-Sundrum. An interesting conclusion is that the torsion-axion duality arising in a stringy scenario via the second rank antisymmetric Kalb-Ramond field leads to conservation of parity in the gravity sector in any dimension. However, parity violating interactions do appear for spin-1/2 fermions in such theories, which can have crucial phenomenological implications.Received: 17 July 2003, Revised: 12 February 2004, Published online: 23 April 2004 相似文献
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