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Odd Number (odd + number)
Selected AbstractsInclusion Complexes for Use in Room-Temperature Gas-Sensor DesignEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 33 2007Liwei Mi Abstract The inclusion complex [{Co(bpy)(H2O)4}·(fcds)]n (1), which has been constructed using the guest molecule ferrocene-1,1,-disulfonate (fcds), the bridging ligand 4,4,-bipyridine (bpy) and d7 Co2+, contains an infinite zigzag chain formed by the central CoII ion and the bridging bpy ligand. Guest fcds molecules lie between two adjacent zigzag chains. The highly conjugated structure of complex 1 means that it can be used as a metal-organic semiconductor, and it also shows a high response to liquefied petroleum gas (LPG) and ethanol/petroleum ether (EP) at room temperature. The inclusion complexes [{Co(bpp)2(H2O)2}·(fcds)·4H2O]n [2; bpp = 1,3-bis(4-pyridyl)propane] and [{Zn(bpy)(H2O)4}·(fcds)]n (3), on the other hand, cannot be employed as room-temperature gas sensors because they are insulators. The electrical resistivity of inclusion complex [{Ni(bpy)(H2O)4}·(fcds)]n (4) is 621 M,, whereas that of [{Co(bpy)(H2O)4}SO4·(4-abaH)2·3H2O]n (5) (4-abaH = 4-aminobenzoic acid) is only 137 M,. This means that the semi-conducting properties of such inclusion complexes depend on both the conjugated structure and the central metal ions. Furthermore, conjugated inclusion complexes with an odd number of electrons could be useful for the design of highly selective room-temperature gas sensors.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Synchronization patterns in spaghetti-like nanoclustersINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 15 2008Acep Purqon Abstract Spaghetti-like nanoclusters concern disordered shapes and irregular shape fluctuations in few correlated biological lipids. We evaluate the shape fluctuations by introducing Symmetry- S as a physical parameter for measuring symmetry degrees and detecting shape transitions. From numerical simulation of few correlated lipids of POPC and POPE at 300 K and 340 K by using molecular dynamics, we investigate the symmetry dynamics for each individual cluster by analyzing both spatiotemporal and frequency. From spatiotemporal analysis, we find several jump motions in S -dynamics and non-Gaussian distributions in S -distribution. Interestingly, the jump motions likely contribute on the existence of transitions in the non-Gaussian distributions. Additionally, even number of lipids show more symmetric than the odd number of lipids and the symmetry distributions shift at higher temperature, while, from three dimension of actual position of symmetry dynamics, they are not easy to configure high symmetry as well as showing certain patterns. From power spectra density analysis, each individual cluster shows nearly random fluctuation. Besides individual clusters, we also investigate mutual clusters. Surprisingly, although individual clusters show fluctuations randomly, mutual clusters show certain direction correlations. Moreover, they show certain patterns in delayed time analysis such as mutual fluctuations periodically occur for same number of lipids. It indicates that an existence of synchronization patterns occur in shape fluctuations of spaghetti-like nanoclusters. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [source] Predictive and interpolative biplots applied to canonical variate analysis in the discrimination of vegetable oils by their fatty acid compositionJOURNAL OF CHEMOMETRICS, Issue 9 2004M. Rui Alves Abstract The fatty acid profiles of 120 commercial unblended peanut, corn, soybean and sunflower vegetable oils and 17 commercial brands of blended edible oils were determined by HRGC/FID/capillary column, including several cis and trans isomers of mono-, di- and tri-unsaturated fatty acids as well as fatty acids with an odd number of carbon atoms. Although many statistical techniques may show some usefulness in the description and analysis of the data obtained, predictive biplots applied to canonical variate analysis prove to be a very useful way of carrying out interpretations and an important aid in building up models, while interpolative biplots display great advantages in the utilization of models for classification purposes on a day-to-day basis. Furthermore, these biplots require only a modest understanding of statistical tools, since all judgements are made regarding original fatty acids and original measuring units. Copyright © 2005 John Wiley & Sons, Ltd. [source] Synthesis, characterization, and in vitro degradation of thermotropic polyesters and copolyesters based on terephthalic acid, 3-(4-hydroxyphenyl)propionic acid, and glycolsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2001Minoru Nagata Abstract A new series of thermotropic liquid-crystalline (LC) polyesters were prepared from a diacyl chloride derivative of 4,4,-(terephthaloyldioxy)-di-4-phenylpropionic acid (PTP) and glycols with a different number of methylene groups (n) [HO(CH2)n OH, n = 6,10, 12] by high-temperature solution polycondensation in diphenyl oxide. PTP6/10 and PTP6/hydroquinone (H) LC copolyesters were also prepared according to a similar procedure. The chemical structure, LC, phase-transition behaviors, thermal stability, and solubility were characterized by elemental analysis, Fourier transform infrared spectroscopy, 1H and 13C NMR spectra, differential scanning calorimetry (DSC), thermogravimetric analysis, and a polarizing light microscope. The melting and isotropization temperatures decreased in a zigzag manner as the number of n increased. All of the polyesters formed a nematic phase with the exception of PTP8. The temperature ranges of the mesophase (,T) were much wider for the polyesters with an odd number of n's than those with an even number. ,T increased markedly for the PTP6/10 and PTP6/H copolyesters. The in vitro degradations of the polymers were ascertained by enzymatic hydrolysis and alkaline hydrolysis. The model compound, PTP dihexylester, was synthesized and found to be degraded into terephthalic acid, 3-(4-hydroxyphenyl)propionic acid, and 1-hexanol by Rhizopus delemar lipase, but PTPn homopolyesters and PTP6/10 and PTP6/H copolyesters were resistant to Rhizopus delemar hydrolysis. They were degradable in a sodium hydroxide buffer solution of pH 12 at 60 °C, depending on the number of n's and the copolymer composition. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3043,3051, 2001 [source] Predicted signs of reduced two-bond spin,spin coupling constants (2hKX,Y) across X,H,Y hydrogen bondsMAGNETIC RESONANCE IN CHEMISTRY, Issue 5 2004Janet E. Del Bene Abstract The reduced two-bond Fermi-contact terms and the reduced spin,spin coupling constants 2hKX,Y across X,H,Y hydrogen bonds for complexes stabilized by C,H,N, N,H,N, O,H,N, F,H,N, C,H,O, O,H,O, F,H,O and C,H,F hydrogen bonds are positive. The NMR Triplet Wavefunction Model (NMRTWM) indicates that the signs of the reduced FC terms and 2hKX,Y are determined by excited triplet states that have an odd number of nodes intersecting the X,Y axis between X and Y, thereby leading to an antiparallel alignment of the nuclear magnetic moments of atoms X and Y. Copyright © 2004 John Wiley & Sons, Ltd. [source] Spin-dependent electron tunnelling and spin relaxation in quantum dots in regime with filling factor of around twoPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 8 2007S. Tarucha Abstract Spin-dependent electron tunnelling and spin relaxation were studied for a quantum dot in the regime with a filling factor between two and four. In this regime, the electronic configuration of a quantum dot undergoes transitions between a spin singlet and triplet states for an even number of electrons, and between two doublet states for an odd number of electrons. These transitions were clearly distinguished by using quantum wires as spin filtering contact leads to the dot. In addition, the temporal behaviour of electron tunnelling was studied for a quantum dot in a similar filling factor regime, using a quantum point contact as a charge sensor. Electron tunnelling through the dot in a spin singlet state could be well distinguished from that in a triplet state using the fact that the tunnelling rate was much larger for the triplet state. The difference in the tunnelling rate was also used to derive a triplet-to-singlet-state relaxation time. The obtained relaxation time agreed fairly well with that predicted by the theory of spin-orbit interaction. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Control of electron transport through a quantum wire by side-attached nanowiresPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue S1 2004P. A. Orellana Abstract A system of arrays of nanowires side-coupled to a quantum wire is studied. Transport through the quantum wire is investigated by using a noninteracting-electron Anderson tunneling Hamiltonian. An analytical expression of the conductance at zero temperature is given, showing a band with alternating forbidden and allowed minibands due to the discrete structure of the nanowires. The conductance is found to exhibit a forbidden miniband in the center of the band for an odd number of sites in the nanowires, while shows an allowed band for an even number. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] (111)p microtwinning in SrRuO3 thin films on (001)p LaAlO3ACTA CRYSTALLOGRAPHICA SECTION B, Issue 6 2009Y. Han SrRuO3 (SRO) thin films grown on (001)p (p = pseudocubic) oriented LaAlO3 (LAO) by pulsed laser deposition have been characterized using transmission electron microscopy. Observations along the ,100,p directions suggests that although the SRO layer maintains a pseudocube-to-pseudocube orientation relationship with the underlying LAO substrate, it has a ferroelastic domain structure associated with a transformation on cooling to room temperature to an orthorhombic Pbnm phase (a,a,c+ Glazer tilt system). In addition, extra diffraction spots located at ±1/6(ooo)p and ±1/3(ooo)p (where `o' indicates an index with an odd number) positions were obtained in ,110,p zone-axis diffraction patterns. These were attributed to the existence of high-density twins on {111}p pseudocubic planes within the SrRuO3 films rather than to more conventional mechanisms for the generation of superstructure reflections. [source] Morphological Aspects of In Vivo Cleavage in Myocastor coypus (coypu)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2004A. E. Felipe Summary The objective of the present work was to characterize the in vivo cleavage stage of Myocastor coypus embryos. For this purpose a colpocytological follow-up and controlled mating of 18 females were performed. Specimens from the beginning of the first cleavage to the acquisition of a morula appearance were considered to be in cleavage stage. Embryos in cleavage were collected between days 3 and 6 post-coitus. Of the collected embryos, 80% presented an even number of blastomeres and the remaining 20% an odd number. Embryos from 3 to 7 cells were blastomere associations in a spherical disposition within the zona pellucida. Blastomeres were spherical or ovoid, presenting slight flattening in areas contacting with other blastomeres. Embryos of 8 and 9 cells were as a group of blastomeres slightly elongated, surrounded by a spherical zona pellucida. The percentage of peri-vitelline space occupied by the embryonic mass ranged from 74.1 to 95.8% for all the substages. The cleavage pattern, developed in the oviduct, was of a rotational holoblastic type and asynchronic. [source] Graph-set and packing analysis of hydrogen-bonded networks in polyamide structures in the Cambridge Structural DatabaseACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2000W. D. Samuel Motherwell The hydrogen-bond networks and crystal packing of 81 unique secondary di- and polyamides in the Cambridge Structural Database are investigated. Graph-set analysis, as implemented in the RPluto program, is used to classify network motifs. These have been rationalized in terms of the relative dispositions of the amide groups. Peptide and retropeptides exhibit significant conformational flexibility, which permits alternative hydrogen-bonding patterns. In peptides, dihedral angles of ,,,,, 105° allow an antiparallel ladder arrangement, containing rings of either the same or alternating sizes. For retropeptides, and diamides with an odd number of CH2 spacers, this conformation leads to a parallel ladder with rings of equal size. If , approaches ,60° and , 180°, ladders adopt a helical twist, and if the conformation is distorted further, a three-dimensional network is usually adopted. Diamides with aromatic or an even number of CH2 spacers generally form either antiparallel ladders or sheets, although some exhibit both polymorphs. Symmetry relationships within and between hydrogen-bonded chains, ladders and sheets in the crystal packing have also been analysed. Polyamides form considerably more complex networks, although many of the structural motifs present in the diamides occur as components of these networks. [source] Demonstration of "Möbius" Aromaticity in Planar MetallacyclesCHEMISTRY - A EUROPEAN JOURNAL, Issue 26 2010Michael Mauksch Dr. Abstract Möbius aromaticity, predicted by Edgar Heilbronner in 1964, is a stabilizing effect exhibited by 4,n electron fully conjugated cyclic molecules (or transition states) with an odd number of orbital phase inversions. Although it has previously been suggested that this effect might also apply to planar metallacycles in which a transition metal employs a d orbital in ,-type binding mode, only very few examples of stable twisted molecules composed of main group elements are known. We report herein, the first computationally confirmed 4,n,, aromatic planar metallacyclic examples and their building principles. Aromatic stabilization energy (ASE) of a 8,, metalla-cycloheptatriene [Fe(CH)6H2], with four doubly occupied , orbitals and a HOMA value of +0.80 (cf. benzene=+1.0), an NICS(0) value of ,8.5 (benzene=,9.8, NICS=nucleus independent chemical shift), and with one phase inversion, is +27.5,kcal,mol,1 (about two-thirds of the value for benzene). In contrast, an unknown non-Möbius 1,4-dimetallabenzene [Fe2(CH)4H4], also with 8,, electrons, and without phase inversions, has an ASE of ,4.1,kcal,mol,1 and a NICS(0)=+15.6, indicative of antiaromaticity. Aromaticity of the proposed Möbius aromatic metallacycles is confirmed by using magnetic (NICS(0), NICS(1)zz, ,1H) and geometric (HOMA) aromaticity criteria, planarity, and near equalized CC bond lengths, bonding analysis (Wiberg bond indices, NBO, and NLMO analysis). The role of wave function boundary conditions (periodic vs. antiperiodic) in chemistry is further stressed, being equivalent to Zimmerman's concept of nodal parity for Möbius/Hückel systems. [source] Crystallization kinetics of poly(trimethylene terephthalate)POLYMER ENGINEERING & SCIENCE, Issue 2 2001Hoe H. Chuah The bulk isothermal crystallization kinetics of poly(trimethylene terephthalate) (PTT) was studied using a differential scanning calorimeter. Avrami's theory was used to analyze the data. Based on crystallinity growth rate, Avrami rate constant, K, and crystallization half-time, PTT's crystallization rate is between those of poly(butylene terephthalate) (PBT) and poly(ethylene terephthalate) (PET) when compared at the same degree of undercooling. PBT has the highest crystallization rate with K in the order of 10,2 to 10,1 min,n. It is about an order of magnitude faster than PTT at 10,3 to 10,2 min,n, which in turn is an order of magnitude faster than PET with K of 10,4 to 10,2 min,n. Contrary to previous reports (PTT was not included in the study) that aromatic polyesters with odd numbers of methylene units were more difficult to crystallize than the even-numbered polyesters, PTT did not fit in the prediction and did not follow the odd-even effect. [source] | ||||||||||||||||