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491.
Alper Tolga olak Ferda olak Demet Akduman Okan Zafer Yeilel Orhan Büyükgüngr 《Solid State Sciences》2009,11(11):1908-1918
In this study, three novel Cu(II)-pyridine-2,5-dicarboxylate (pydc) complexes with 4-methylimidazole (4-Meim), [Cu(pydc)(H2O)(4-Meim)2]·H2O (1), imidazole (im), {[Cu(μ-pydc)(im)2]·2H2O}n (2), and 3,4-dimethylpyridine (dmpy), [Cu(μ-pydc)(H2O)(dmpy)]n (3) have been synthesized. Elemental and thermal analyses, magnetic susceptibilities, IR and UV/vis spectroscopic studies have been performed to characterize the complexes. The molecular structures of mononuclear (1) and polynuclear (2 and 3) complexes have been determined by the single crystal X-ray diffraction technique. In 1 and 2, Cu(II) ions have distorted square planer geometry, while 3 has distorted octahedral coordination. The pyridine-2,5-dicarboxylate exhibits three different coordination modes namely bidentate (1), tridentate (2) and tetradentate (3). The complex 1 is further constructed to form three-dimensional framework by hydrogen bonding, C–Hπ and ππ stacking interactions. The adjacent chains of 2 and 3 are then mutually linked via hydrogen bonding, ππ and C–Hπ interactions, which are further assembled to form three-dimensional framework. 1 exhibits the magnetic moment value of 1.70 BM, which corresponds to one of the unpaired electron, while the polynuclear complexes 2 and 3 exhibit 1.58 and 1.46 BM, which is lower than the spin only value for one unpaired electron, indicates to antiferromagnetic effect. The first thermal decomposition process of all the complexes is endothermic dehydration. This stage is followed by partial (or complete) decomposition of the neutral and pydc ligands. In the later stage, the remained organic residue exothermically burns. The final decomposition products which identified by IR spectroscopy were the CuO. 相似文献
492.
Maxym Vasylyev Dr. Howard Alper Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(7):1287-1290
Fleetingly formyl : A new rhodium‐catalyzed hydroformylation reaction of N‐allyl oxazolidines, carried out under a CO/H2 atmosphere, followed by a diastereoselective deformylative cyclization affords hexahydropyrrolo[2,1‐b]oxazoles in good yields. The reaction proceeds by a unique hydroformylation–deformylation sequence in which the formyl group virtually substitutes for the {CH2? O} fragment of the oxazolidine heterocycle.
493.
Ebru Cubuk Demiralay Guleren Alsancak Sibel A. Ozkan 《Journal of separation science》2009,32(17):2928-2936
In this study, pKa values were determined by using the dependence of the capacity factor on the pH of the mobile phase for four ionizable substances, namely, tenoxicam, piroxicam, meloxicam, and naproxen (I.S.). The effect of the mobile phase composition on the ionization constant was studied by measuring the pKa at different ACN concentrations, ranging from 30 to 40%. The adequate condition for the chromatographic determination of these compounds in pharmaceutical dosage forms was established based on the different retention behaviors of the species. An octadecylsilica Nucleosil C18 column (150×4.6 mm, 5 μm) was used for all the determinations. The chromatographic separation of oxicams was carried out using acetonitrile (ACN)/water at 35% v/v, containing 65 mM phosphoric acid and UV detection at a wavelength of 355 nm. The method developed was successfully applied to the simultaneous determination of these drug compounds in laboratory‐prepared mixtures and their commercial pharmaceutical dosage forms. Each analysis requires no longer than 12 min. 相似文献
494.
We study a non-cooperative game for joint replenishment by n firms that operate under an EOQ-like setting. Each firm decides whether to replenish independently or to participate in joint
replenishment, and how much to contribute to joint ordering costs in case of participation. Joint replenishment cycle time
is set by an intermediary as the lowest cycle time that can be financed with the private contributions of participating firms.
We characterize the behavior and outcomes under undominated Nash equilibria. 相似文献
495.
We develop a two-stage stochastic programming model for a humanitarian relief logistics problem where decisions are made for pre- and post-disaster rescue centers, the amount of relief items to be stocked at the pre-disaster rescue centers, the amount of relief item flows at each echelon, and the amount of relief item shortage. The objective is to minimize the total cost of facility location, inventory holding, transportation and shortage. The deterministic equivalent of the model is formulated as a mixed-integer linear programming model and solved by a heuristic method based on Lagrangean relaxation. Results on randomly generated test instances show that the proposed solution method exhibits good performance up to 25 scenarios. We also validate our model by calculating the value of the stochastic solution and the expected value of perfect information. 相似文献
496.
Mathematical Programming - We study the minimization of a rank-one quadratic with indicators and show that the underlying set function obtained by projecting out the continuous variables is... 相似文献
497.
Öztürk Tuğçe Pınar Gelir Ali Keshtiban Nahid Aghabalapoor Yargı Önder Özdemir Onur B. Mucur Selin Pıravadılı Seçgin Alper 《Journal of Solid State Electrochemistry》2023,27(4):885-894
Journal of Solid State Electrochemistry - The motion of the ion pairs under the applied electric field is an important phenomenon in the storage properties of the capacitive devices. In this study,... 相似文献
498.
In this work submicron barium sulfate (BaSO4) particles were synthesized successfully by chemical precipitation technique. We focused on the effects of pH and additives on the size and morphology of BaSO4 crystals. Polyacrylic acid, polyvinyl sulfonic acid and ethylenediaminetetraacetic acid were used as crystal growth modifiers. BaSO4 crystals were characterized using scanning electron microscopy, X‐ray diffraction, and Fourier transform infrared resonance techniques. The results show that the submicron BaSO4 particles have been synthesized successfully and the particle size of the barium sulfate was effectively controlled under the experimental conditions. Experimental studies revealed that the additive concentration and pH had great effect on the morphology and size of barium sulfate. 相似文献