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51.
52.
Slater's transition state concept and the relativistic numerical Hartree-Fock-Slater theory has been used to calculate the electronegativity and first ionization potential for the rare earth atoms. Based on these results the electron affinity has also been estimated. The theory predicts almost constant values of the electronegativity as 2 eV, first ionization potential as 8 eV and the electron affinity of -(4–5) eV respectively.This work is dedicated to the memory of Prof. J. C. Slater.Alexander von Humboldt fellow, on leave from school of chemistry, University of Hyderabad, India. 相似文献
53.
Summary Nitrosyl chloride has been treated with [Ni(PPh3)2X2] (X = Cl, Br, NCS or NO3) to obtain [Ni(PPh3)XCl]2 (X=Cl, Br, NCS or NO3) and [Ni(OPPh3)(SCN)Cl]2. The compounds obtained were characterised by analyses, infrared (including far i.r.) and visible spectral studies, magnetic moment and conductivity measurements and many chemical reactions. It is proposed that the compounds have a dimeric structure with a distorted tetrahedral environment around the nickel atom and chloro-bridges. 相似文献
54.
Tangoulis V Malamatari DA Soulti K Stergiou V Raptopoulou CP Terzis A Kabanos TA Kessissoglou DP 《Inorganic chemistry》1996,35(17):4974-4983
Two mixed-valence Mn(III)Mn(II) complexes and a homo-valence Mn(II) trinuclear manganese complex of stoichiometry Mn(III)Mn(II)Mn(III)(5-Cl-Hsaladhp)(2)(AcO)(4)(MeOH)(2).4CH(3)OH (1a), Mn(III)Mn(II)Mn(III) (Hsaladhp)(2)(AcO)(2)(5-Cl-Sal)(2)(thf)(2) (3a) and Mn(II)Mn(II)Mn(II) (AcO)(6)(pybim)(2) (1b) where H(3)saladhp is a tridentate Schiff base ligand and pybim a neutral bidentate donor ligand, have been structurally characterized by using X-ray crystallography. The structurally characterized mixed-valence complexes have strictly 180 degrees Mn(III)-Mn(II)-Mn(III) angles as required by crystallographic inversion symmetry. The complexes are valence trapped with two terminal Mn(III) ions showing Jahn-Teller distortion along the acetate or salicylate-Mn(III)-X axis. The Mn.Mn separation is 3.511 ? and 3.507 ? respectively. The mixed-valence complexes have S = (3)/(2) ground state and the homovalence complex S = (5)/(2), with small antiferromagnetic exchange J couplings, -5.6 and -1.8 cm(-1), respectively, while the powder ESR spectra at 4 K show a broad low field signal with g approximately 4.3 for Mn(III)Mn(II)Mn(III) and a broad temperature-dependent signal at g = 2 for Mn(II)Mn(II)Mn(II). Crystal data for 1a: [C(36)H(60)O(20)N(2)Cl(2)Mn(3)], triclinic, space group P&onemacr;, a = 9.272(7) ?, b = 11.046(8) ?, c = 12.635(9) ?, alpha = 76.78(2) degrees, beta = 81.84(2) degrees, gamma = 85.90(2) degrees, Z = 1. Crystal data for 3a: [C(48)H(56)O(18)N(2)Cl(2)Mn(3)], monoclinic, space group P2(1)/n, a = 8.776(3) ?, b = 22.182(7) ?, c = 13.575(4) ?, beta = 94.44(1) degrees, Z = 2. Crystal data for 1b: [C(36)H(36)O(12)N(6)Mn(3)], triclinic, space group P&onemacr;, a = 13.345(6) ?, b = 8.514(4) ?, c = 9.494(4) ?, alpha = 75.48(1) degrees, beta = 75.83(1) degrees, gamma = 76.42(1) degrees, Z = 1. 相似文献
55.
Kali Yassine Saad Maarouf Benjelloun Khalid Khairallah Charles 《Nonlinear dynamics》2018,92(2):557-573
Nonlinear Dynamics - In a small tubular neighborhood of the heteroclinic orbits, we establish a local coordinate system by using the foundational solutions of the linear variational equation of the... 相似文献
56.
The paper concerns vibration surveillance during ball end milling of curved flexible details. Here is explained dynamic analysis of non-stationary vibrating system, from which are separated subsystems: modal, structural and connective. An assessment of coincidence of the calculation model results with those from investigation on milling machine is performed. Ball end milling of flexible details is observed very frequently in case of modern machining centres. It is obvious that tool-workpiece relative vibration plays principal role during cutting process. The most important task is to create a FE-model of machined flexible detail and obtain its good correlation with the results of experimental modal analysis. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
57.
Koteswara Rao Ch. P. Rao T. B. Charan G. Kali Srinu B. Maturi S. R. 《Russian Journal of General Chemistry》2019,89(5):1023-1028
Russian Journal of General Chemistry - In the present study a new series of 2-{4-[5-(5-substituted arylpyrimidin-2-yl)-1H-pyrazol-3-yl] phenyl}thiazolo[4,5-b]pyridine derivatives (11a–11j)... 相似文献
58.
Srinu B. Parameshwar R. Kali Charan G. Srinivas E. Koteswara Rao Ch. P. Narendra Sharath Chandra J. N. Naresh Varma S. 《Russian Journal of General Chemistry》2019,89(4):836-843
Russian Journal of General Chemistry - A novel series of 2-(4-chlorobenzylamino)-4-(cyclohexylmethylamino)-pyrimidine-5-carboxamide derivatives are synthesized and their structures are confirmed by... 相似文献
59.
Stable isotopes of hydrogen and oxygen were used to examine how the isotopic signal of meteoric water is modified as it travels through soil and epikarst into two caves in Florida. Surface and cave water samples were collected every week from February 2006 until March 2007. The isotopic composition of precipitation at the investigated sites is highly variable and shows little seasonal control. The delta18O vs. delta2H plot shows a mixing line having a slope of 5.63, suggesting evaporation effects dominate the isotopic composition of most rainfall events of less than 8 cm/day, as indicated by their low d-excess values. The delta18O values of the drip water show little variability (<0.6 per thousand), which is loosely tied to local variations in the seasonal amount of precipitation. This is only seen during wintertime at the Florida Caverns site. The lag time of over two months and the lack of any relationship between rainfall amount and the increase in drip rate indicate a dominance of matrix flow relative to fracture/conduit flow at each site. The long residence time of the vadose seepage waters allows for an effective isotopic homogenisation of individual and seasonal rainfall events. We find no correlation between rainfall and drip water delta18O at any site. The isotopic composition of drip water in both caves consistently tends to resemble the amount-weighted monthly mean rainfall input. This implies that the delta18O of speleothems from these two caves in Florida cannot record seasonal cycle in rainfall delta18O, but are suitable for paleoclimate reconstructions at inter-annual time scales.dagger. 相似文献
60.