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81.
Baunemann A Bekermann D Thiede TB Parala H Winter M Gemel C Fischer RA 《Dalton transactions (Cambridge, England : 2003)》2008,(28):3715-3722
Novel mixed amido/imido/guanidinato complexes of niobium are reported. The complexes were synthesized by insertion of two equivalents of di-isopropylcarbodiimide (i-Pr-cdi) or bis-cyclohexylcarbodiimide (Cy-cdi) respectively, into the niobium-amido bonds of [Nb(NR(2))(3)(N-t-Bu)] (, R = Me; , R = Et) starting out from [NbCl(3)(N-t-Bu)(py)(2)] and the respective LiNR(2) reagent (py = pyridine). Four representative examples of these mixed ligand amido/imido/guanidinato compounds were synthesized and were characterized by (1)H-NMR, (13)C-NMR, (15)N-NMR, CHN-analysis, mass spectrometry and infra-red spectroscopy. The molecular structures of [Nb(NR(2)){eta(2)-(i-Pr-N)(2)C(NR(2))}(2)(N-t-Bu)] (, R = Me; , R = Et) in the solid state were determined by single-crystal X-ray diffraction studies and are discussed together with the molecular structure of the starting compound [Nb(NMe(2))(3)(N-t-Bu)] (). The thermal properties of the new compounds depend on the substitution at the guanidinato ligand. Complexes of i-Pr-cdi are significantly more volatile than complexes of Cy-cdi as revealed by thermogravimetric analysis. Preliminary experiments using as a single-molecule source for metal-organic chemical vapour deposition (MOCVD) in the absence of ammonia indicate the formation of the stoichiometric, and surprisingly carbon-free, cubic niobium nitride phase. 相似文献
82.
Inexpensive copper catalysts enabled modular one-pot multicomponent syntheses of fully decorated triazoles through a sustainable "click" reaction/direct arylation sequence. 相似文献
83.
Harish Garg 《Computational & Mathematical Organization Theory》2017,23(4):546-571
Pythagorean fuzzy set, an extension of the intuitionistic fuzzy set which relax the condition of sum of their membership function to square sum of its membership functions is less than one. Under these environment and by incorporating the idea of the confidence levels of each Pythagorean fuzzy number, the present study investigated a new averaging and geometric operators namely confidence Pythagorean fuzzy weighted and ordered weighted operators along with their some desired properties. Based on its, a multi criteria decision-making method has been proposed and illustrated with an example for showing the validity and effectiveness of it. A computed results are compared with the aid of existing results. 相似文献
84.
Ajay Sharma Harish Sharma Annapurna Bhargava Nirmala Sharma Jagdish Chand Bansal 《Memetic Computing》2017,9(4):311-331
The power system is a complex interconnected network which can be subdivided into three components: generation, distribution, and transmission. Capacitors of specific sizes are placed in the distribution network so that losses in transmission and distribution is minimum. But the decision of size and position of capacitors in this network is a complex optimization problem. In this paper, Limaçon curve inspired local search strategy (LLS) is proposed and incorporated into spider monkey optimization (SMO) algorithm to deal optimal placement and the sizing problem of capacitors. The proposed strategy is named as Limaçon inspired SMO (LSMO) algorithm. In the proposed local search strategy, the Limaçon curve equation is modified by incorporating the persistence and social learning components of SMO algorithm. The performance of LSMO is tested over 25 benchmark functions. Further, it is applied to solve optimal capacitor placement and sizing problem in IEEE-14, 30 and 33 test bus systems with the proper allocation of 3 and 5-capacitors. The reported results are compared with a network without a capacitor (un-capacitor) and other existing methods. 相似文献
85.
Naik PK Lopus M Aneja R Vangapandu SN Joshi HC 《Journal of computer-aided molecular design》2012,26(2):233-247
Our screen for tubulin-binding small molecules that do not depolymerize bulk cellular microtubules, but based upon structural
features of well known microtubule-depolymerizing colchicine and podophyllotoxin, revealed tubulin binding anti-cancer property
of noscapine (Ye et al. in Proc Natl Acad Sci USA 95:2280–2286, 1998). Guided by molecular modelling calculations and structure–activity relationships we conjugated at C9 of noscapine, a folate
group—a ligand for cellular folate receptor alpha (FRα). FRα is over-expressed on some solid tumours such as ovarian epithelial
cancers. Molecular docking experiments predicted that a folate conjugated noscapine (Targetin) accommodated well inside the
binding cavity (docking score −11.295 kcal/mol) at the interface between α- and β-tubulin. The bulky folate moiety of Targetin
is extended toward lumen of microtubules. The binding free energy (ΔG
bind) computed based on molecular mechanics energy minimization was −221.01 kcal/mol that revealed favourable interaction of Targetin
with the receptor. Chemical synthesis, tubulin-binding experiments, and anti-cancer activity in vitro corroborate fully well
with the molecular modelling experiments. Targetin binds tubulin with a dissociation constant (K
d value) of 149 ± 3.0 μM and decreases the transition frequencies between growth and shortening phases of microtubule assembly
dynamics at concentrations that do not alter the total polymer mass. Cancer cells in general were more sensitive to Targetin
compared with the founding compound noscapine (IC50 in the range of 15–40 μM). Quite strikingly, ovarian cancer cells (SKOV3 and A2780), known to overexpress FRα, were much
more sensitive to targetin (IC50 in the range of 0.3–1.5 μM). 相似文献
86.
Satish A. Mahadik D. B. Mahadik M. S. Kavale V. G. Parale P. B. Wagh Harish C. Barshilia Satish C. Gupta N. D. Hegde A. V. Rao 《Journal of Sol-Gel Science and Technology》2012,63(3):580-586
A facile method was developed for the fabrication of the methyltriethoxysilane based transparent and superhydrophobic coating on glass substrates. The transparent and hydrophobic coatings were deposited on the glass substrates, using spray deposition method followed by surface modification process. A spray deposition method generates hierarchical morphology and post surface modification with monofunctional trimethylchlorosilane decreases the surface free energy of coating. These combined effects of synthesis produces bio-inspired superhydrophobic surface. The deposited coating surface shows high optical transparency, micro-nano scale hierarchical structures, improved hydrophobic thermal stability, static water contact angle of about 167° ± 1°, low sliding angle about 2° ± 1° and stable superhydrophobic nature. This paper provides the very simple sol–gel approach to the fabrication of optically transparent, thermally stable superhydrophobic coating on glass substrates. This fabrication strategy may easily extend to the industrial scale up and high-technology fields. 相似文献
87.
Susovan Bhowmik Sudip Kumar Ghosh Samar Layek Prof. Harish Chandra Verma Dr. Sankar Prasad Rath 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(41):13025-13037
Reported herein is a hitherto unknown family of diiron(III)‐μ‐hydroxo bisporphyrins in which two different spin states of Fe are stabilized in a single molecular framework, although both cores have identical molecular structures. Protonation of the oxo‐bridged dimer ( 2 ) by using strong Brønsted acids, such as HI, HBF4, and HClO4, produce red μ‐hydroxo complexes with I3? ( 3 ), BF4? ( 4 ), and ClO4? ( 5 ) counterions, respectively. The X‐ray structure of the molecule reveals that the Fe? O bond length increases on going from the μ‐oxo to the hydroxo complex, whereas the Fe‐O(H)‐Fe unit becomes more bent, which results in the smallest known Fe‐O(H)‐Fe angles of 142.5(2) and 141.2(1)° for 3 and 5 , respectively. In contrast, the Fe‐O(H)‐Fe angle remains unaltered in 4 from the corresponding μ‐oxo complex. The close approach of two rings in a molecule results in unequal core deformations in 3 and 4 , whereas the cores are deformed almost equally but to a lesser extent in 5 . Although 3 was found to have nearly high‐spin and admixed intermediate Fe spin states in cores I and II, respectively, two admixed intermediate spin states were observed in 4 . Even though the cores have identical chemical structures, crucial bond parameters, such as the Fe? Np, Fe? O, and Fe???Ctp bond lengths and the ring deformations, are all different between the two FeIII centers in 3 and 4 , which leads to an eventual stabilization of two different spin states of Fe in each molecule. In contrast, the two Fe centers in 5 are equivalent and assigned to high and intermediate spin states in the solid and solution states, respectively. The spin states are thus found to be dependent on the counterions and can also be reversibly interconverted. Upon protonation, the strong antiferromagnetic coupling in the μ‐oxo dimer (J, ?126.6 cm?1) is attenuated to almost zero in the μ‐hydroxo complex with the I3? counterion, whereas the values of J are ?36 and ?42 cm?1, respectively, for complexes with BF4? and ClO4? counterions. 相似文献
88.
We examine a Markov tree (MT) model for option pricing in which the dynamics of the underlying asset are modeled by a non-IID process. We show that the discrete probability mass function of log returns generated by the tree is closely approximated by a continuous mixture of two normal distributions. Using this normal mixture distribution and risk-neutral pricing, we derive a closed-form expression for European call option prices. We also suggest a regression tree-based method for estimating three volatility parameters σ, σ+, and σ− required to apply the MT model. We apply the MT model to price call options on 89 non-dividend paying stocks from the S&P 500 index. For each stock symbol on a given day, we use the same parameters to price options across all strikes and expires. Comparing against the Black–Scholes model, we find that the MT model’s prices are closer to market prices. 相似文献
89.
Harish Gopalan 《International Journal of Computational Fluid Dynamics》2013,27(3):285-290
‘Stream function as a coordinate approach’ (SFC) combined with compact high-order finite difference schemes has been developed and applied to aeroacoustics and unsteady aerodynamics problems. Straightforward implementation of SFC creates coarse grids at the vicinity of stagnation points that smears high-order numerical computations. Grid clustering is employed to resolve coarse grid near stagnations points. The agreement between numerical results and particle image velocimetry (PIV) measurements for flapping airfoil shows the robustness of the current approach for performing high-order computations. 相似文献
90.