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81.
L. Acar 《Journal of Optimization Theory and Applications》1995,84(2):251-271
In recent years, the finite-horizon quadratic minimization problem has become popular in process control, where the horizon is constantly rolled back. In this paper, this type of control, which is also called the receding horizon control, is considered for interconnected systems. First, the receding horizon control equations are formulated; then, some stability conditions depending on the interconnection norms and the horizon lengths are presented. For -coupled systems, stability results similar to centralized systems are obtained. For interconnected systems which are not -coupled, the existence of a horizon length and a corresponding stabilizing receding horizon control are derived. Finally, the performance of a locally computed receding horizon control for time-invariant and time-varying systems with different updating intervals is examined in an example. 相似文献
82.
A new HPLC-DAD method was developed and validated for simultaneous determination of six main phenylethanoid glycosides (calceolarioside D, neocalceolarioside D, verbascoside, isoverbascoside, leucoseptoside A and martynoside) in the aerial parts of four Scutellaria L. taxa from flora of Turkey. All standard compounds showed a good linearity (R 2 > 0.999) in a relatively wide concentration range (1–120 μg/mL). The LOD of the compounds was in the range of 0.104–1.295 μg/mL and the LOQ was in the range of 0.450–2.536 μg/mL. The recoveries of the selected compounds were calculated in the range of 97.46–117.85%. The amounts of the phenylethanoid glycosides showed variation in the extracts. The developed method was found to be accurate, precise and reproducible, and successfully applied to identify and quantify the phenylethanoid glycoside composition of Scutellaria species. 相似文献
83.
Halit Kantekin Ümmühan Ocak Yaşar Gök Irfan Acar 《Journal of inclusion phenomena and macrocyclic chemistry》2004,48(3-4):95-101
A new (E, E)-dioxime (H 2 L) containing a diazadioxadithia macrocyclic moieties has been synthesized by reaction of an aromatic primary amine with cyanogendi-N-dioxide. The BF2 +-capped Ni2+ mononuclear complex of this new oxime has been synthesized using a precursor hydrogen-bridged mononuclear Ni2+ complex. The solvent extraction of transition metal cations by (3) and (6) with picrate anion into chloroform has been studied at 25 °C and UV-visible spectroscopy. The extractability and selectivity of transition metal picrates, (Pb2+, Ni2+, Co2+, Cd2+, Zn2+, Cu2+, Ag+) has been evaluated. The structures of new compounds are identified by using elemental analysis, 1H and 13C-NMR, IR and MS spectral data. 相似文献
84.
Cadmium, copper and lead in soils, sediments and spiked sea water samples have been determined by electrothermal atomic absorption spectrometry (ETAAS) with Zeeman effect background corrector using NH4NO3, Sc, Pd, Sc + NH4NO3, Pd + NH4NO3, Sc + Pd and Sc + Pd + NH4NO3 as chemical modifiers. A comprehensive comparison was made among the modifiers and without modifier in terms of pyrolysis and atomization temperatures, atomization and background absorption profiles, characteristic masses, detection limits and accuracy of the determinations. Sc + Pd + NH4NO3 modifier mixture was found to be preferable for the determination of analytes in soil and sediment certified and standard reference materials, and sea water samples because it increased the pyrolysis temperature up to 900 °C for Cd, 1350 °C for Cu and 1300 °C for Pb. Optimum masses of mixed modifier components found are 20 μg Sc + 4 μg Pd + 8 μg NH4NO3. Characteristic masses of Cd, Cu and Pb obtained are 0.6, 5.3 and 15.8 pg, respectively. The detection limits of Cd, Cu and Pb were found to be 0.08, 0.57 and 0.83 μg l−1, respectively. Depending on the solid sample type, the percent recoveries were increased up to 103% for Cd, Cu and Pb by using the proposed modifier mixture. The accuracy of the determination of analytes in the sea water samples was also increased. 相似文献
85.
Tuncer Acar 《Mathematical Methods in the Applied Sciences》2016,39(10):2685-2695
In this paper, we introduce new modifications of Szász–Mirakyan operators based on (p,q)‐integers. We first give a recurrence relation for the moments of new operators and present explicit formula for the moments and central moments up to order 4. Some approximation properties of new operators are explored: the uniform convergence over bounded and unbounded intervals is established, direct approximation properties of the operators in terms of the moduli of smoothness is obtained and Voronovskaya theorem is presented. For the particular case p = 1, the previous results for q‐Sz ász–Mirakyan operators are captured. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
86.
Ernest Antwi Niamh A. Packer Jordyn M. Ratliff Barbara Marchetti Tolga N. V. Karsili 《Photochemistry and photobiology》2023,99(4):1072-1079
Isoprene is the most abundant nonmethane volatile organic compound emitted into the troposphere by terrestrial vegetation. Reaction with ozone represents an important isoprene removal process from the troposphere and is a well-known source of Criegee intermediates (CIs), which are reactive carbonyl oxides. Three CIs, formaldehyde oxide (CH2OO), methyl vinyl ketone oxide (MVK-oxide) and methacrolein oxide (MACR-oxide) are formed during isoprene ozonolysis. All three CIs contain strongly absorbing ππ* states, electronic excitation, which leads to dissociation to form aldehyde/ketone + oxygen products. Here, we compare the excited state chemistry of CH2OO, MVK-oxide and MACR-oxide in order to ascertain how increasing molecular complexity affects their photodynamics. In CH2OO, vertical excitation to the S2 state leads to prompt O-O bond fission with a unity quantum yield. Branching into both the O (1D) + H2CO (S0) and O (3P) + H2CO (T1) product channels is predicted, with 80% of trajectories dissociating to form the former product pair. Analogous vertical excitation of the lowest energy conformers of MVK-oxide and MACR-oxide also undergoes O-O bond fission to form O + MVK/MACR products—albeit with a nonunity quantum yield. In the latter case, ca. 10% and 25% of trajectories remain as the parent MVK-oxide and MACR-oxide molecules, respectively. Additionally, at most only 5% of the dissociating trajectories form O (3P) + MVK/MACR (T1) products, with a greater fraction forming O (1D) + MVK/MACR (S0) products (cf. CH2OO). This latter observation coupled with the greater fraction of undissociated trajectories aligns with the bathochromic shift in the electronic absorption of the MACR-oxide and MVK-oxide (cf. CH2OO). We discuss the implications of the results in a broader context, including those that are relevant to the atmosphere. 相似文献
87.
Alper Tolga ?olak Okan Zafer Yeilel Tuncer H?kelek Ertan ahin 《Structural chemistry》2008,19(2):285-290
A novel metal–organic coordination polymer framework formulated as {[Zn(dipic)(μ-en)]·3H2O}
n
(1) (catena-poly-μ-ethylenediamine(dipicolinato)zinc(II) trihydrate) has been synthesized and characterized by spectral method (IR), elemental
analysis, thermal analysis (TG, DTG, DTA) and single crystal X-ray diffraction techniques. It crystallizes in the triclinic
system, space group P−1. The asymmetric unit contains three hydrogen-bonded water molecules and the Zn atom is five-coordinated by three N and
two O atoms. In fact, it is a new one-dimensional zinc complex with the peculiarity of having the ethylenediamine ligand very
unusually acting as bridge to form polymeric chains. In the crystal structure, intramolecular O–H···O and intermolecular O–H···O
and N–H···O hydrogen bonds result in the formation of a supramolecular structure, in which they seem to be effective in the
stabilization of the structure. 相似文献
88.
Elif Gungor Mustafa Burak Coban Hulya Kara Yasemin Acar 《Journal of Cluster Science》2018,29(6):967-974
A new cubane-based cobalt(II) cluster, [Co4L4] (1), where H2L?=?2-((E)-(2-hydroxyethylimino) methyl)-4-chlorophenol has been prepared using a solvothermal process and characterized by structural, optical and magnetism. The crystal structure of 1 consists of a tetranuclear Co4O4 core in an open-cubane framework. Each cobalt(II) ion is penta-coordinated in a distorted square pyramidal geometry (τCo1=Co1i?=?0.030, τCo2=Co2i?=?0.023). Furthermore, the photoluminescence analysis indicates that 1 has a strong blue emission which should be attributed to coordination of the metal to the ligand. The temperature dependence of the magnetic susceptibilities of 1 shows antiferromagnetic coupling (J?=???26.61?±?0.01) between cobalt(II) ions. 相似文献
89.
A systematic study on the synthesis of 8‐aminoquinoline derivatives with an n‐butyl group at each alternate position of the quinoline ring was carried out. Skraup Reaction and its Doebner–von Miller variation were used to obtain most of the quinoline ring except for the 2‐butyl‐8‐aminoquinolines and 4‐butyl‐8‐aminoquinolines where the commercially available methylquinoline derivatives were used as precursors. The structures of the synthesized compounds were characterized by FTIR, 1H‐NMR, COSY, 13C‐NMR and HRMS spectra. 相似文献
90.
Handan Günay Alper Tolga Çolak Ersin Temel Özlem Saniye Bayraktar Ferdağ Çolak Orhan Büyükgüngör 《Journal of Coordination Chemistry》2016,69(9):1499-1513
Two coordination polymers with 5-aminoisophthalic acid (H2aip), [Ni(μ-aip)(H2O)2(tmeda)]n (1) and {H2dap[Zn2(μ-aip)(μ3-aip)2]?9H2O}n (2) (H2aip = 5-aminoisophthalic acid, tmeda = N,N,N′-N′-tetramethylethylenediamine, dap = 1,3-diaminopropane) have been synthesized. Elemental and thermal analyses, magnetic susceptibilities, IR, AAS, mass and UV–vis spectroscopic studies have been performed to characterize the compounds. Nickel(II) has octahedral geometry by two oxygens of different carboxylates, bidentate, tmeda as bidentate chelating and two water ligands. Zn(II) has tetrahedral geometry by three oxygens of different carboxylate groups and one nitrogen by amine of aip. 1 crystallizes in the orthorhombic crystal system with space group Pccn and 2 in monoclinic crystal system with space group P21/c. Complex 2 exhibits photoluminescence properties in the solid state at room temperature. This study determined the susceptibility patterns of 1 and 2 against bacterial, yeast and mold micro-organisms. Antimicrobial activities were done on 12 different micro-organisms using the micro-dilution method. Tested microbial species were inhibited by 1 with a Minimum inhibitory concentrations (MIC) of 375–3000 μg mL?1. Compound 2 showed antimicrobial activities against tested micro-organisms with a MIC of 188–1500 μg mL?1. Compound 2 showed antibacterial activity against Legionella pneumophila sg1 375 μg mL?1 (MIC value). 相似文献