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1.
Yoshikazu Kondo Yutaka Harima Koji Hyakutake Nobumitu Yamada Masafumi Uota Go Sakai Tsuyoshi Kijima 《Colloid and polymer science》2007,285(9):1019-1027
The composite films of poly(lactic acid) (PLA) doped with glucosamine(Gluc)-formaldehyde(FA) polymer/sodium dodecylbenzenesulfonate
(SDBS) complexes at 1–5 wt% were synthesized to demonstrate striking improvement of their structural and mechanical properties.
The polymer complexes were obtained by the hydrothermal polymerization of Gluc and FA at a molar ratio of 1:2 in the presence
of SDBS. The atomic ratios of S in to N in (=S/N) in the polymer complexes limitedly range from 0.52 to 0.69, indicating that the complexation develops through the
nonstoichiometric reaction between groups of (Gluc-FA) polymer and ones of SDBS and 31–48% of the groups remain unbound. The PLA composite film doped with 1 wt% (Gluc-FA)/SDBS showed the elongation-at-break of as large
as 194% compared with 37% for PLA film, together with an appreciable increase of the crystallites size (D
200) of PLA from 21.8 to 33.3 nm. 相似文献
2.
Anil Kumar Nain 《Journal of solution chemistry》2007,36(4):497-516
The densities of binary mixtures of formamide (FA) with 1-butanol, 2-butanol, 1,3-butanediol, and 1,4-butanediol, including
those of the pure liquids, over the entire composition range were measured at temperatures (293.15, 298.15, 303.15, 308.15,
313.15 and 318.15) K and atmospheric pressure. From the experimental data, the excess molar volume, V
m
E, partial molar volumes, and , at infinite dilution, and excess partial molar volumes, and , at infinite dilution were calculated. The variation of these parameters with composition and temperature of the mixtures
are discussed in terms of molecular interactions in these mixtures. The partial molar expansivities, and , at infinite dilution and excess partial molar expansivities, and , at infinite dilution were also calculated. The V
m
E values were found to be positive for all the mixtures at each temperature studied, except for FA + 1-butanol which exhibits
a sigmoid trend wherein V
m
E values change sign from positive to negative as the concentration of FA in the mixture is increased. The V
m
E values for these mixtures follow the order: 1-butanol < 2-butanol < 1,3-butanediol < 1,4-butanediol. It is observed that
the V
m
E values depend upon the number and position of hydroxyl groups in these alkanol molecules. 相似文献
3.
Radosław Szmytkowski 《Journal of mathematical chemistry》2009,46(1):231-260
The derivative of the associated Legendre function of the first kind of integer degree with respect to its order, , is studied. After deriving and investigating general formulas for μ arbitrary complex, a detailed discussion of , where m is a non-negative integer, is carried out. The results are applied to obtain several explicit expressions for the associated
Legendre function of the second kind of integer degree and order, . In particular, we arrive at formulas which generalize to the case of (0 ≤ m ≤ n) the well-known Christoffel’s representation of the Legendre function of the second kind, Q
n
(z). The derivatives and , all with m > n, are also evaluated. 相似文献
4.
François Quentel Valentin Mirčeski Maurice L’Her 《Journal of Solid State Electrochemistry》2008,12(1):31-39
Thermodynamics and kinetics of hydrophilic ion transfers across water|n-octanol (W|OCT) interface have been electrochemically studied by means of novel three-phase and thin-film electrodes. Three-phase
electrodes used for thermodynamics measurements comprise edge plane pyrolytic graphite, the surface of which was partly modified
with an ultrathin film of OCT, containing hydrophobic lutetium bis(tetra-tert-butylphthalocyaninato) (Lu[tBu4Pc]2) as a redox probe. The transfers of anions and cations from W to OCT were electrochemically driven by reversible redox transformations
of Lu[tBu4Pc]2 to chemically stable lipophilic monovalent cation and anion , respectively. Upon reduction of Lu[tBu4Pc]2, the transfers of alkali metal cations from W to OCT have been studied for the first time, enabling estimation of their Gibbs
transfer energies. For kinetic measurements, a thin-film electrode configuration has been used, consisting of the same electrode
covered completely with a thin layer of OCT that contained the redox probe and a suitable electrolyte. Combining the fast
and sensitive square-wave voltammetry with thin-film electrodes, the kinetics of , , and Cl− transfers have been estimated.
Dedicated to Professor Dr. Yakov I. Tur’yan on the occasion of his 85th birthday. 相似文献
5.
Kinetics and equilibria for the formation of a 1:1 complex between palladium(II) and chloroacetate were studied by spectrophotometric measurements in 1.00 mol HClO4 at 298.2 K. The equilibrium constant, K, of the reaction
was determined from multi-wavelength absorbance measurements of equilibrated solutions at variable temperatures as log 0.006 with and , and spectra of individual species were calculated. Variable-temperature kinetic measurements gave rate constants for the forward and backward reactions at 298.2 K and ionic strength 1.00 mol as and , with activation parameters and , respectively. From the kinetics of the forward and reverse processes, and were derived in good agreement with the results of the equilibrium measurements. Specific Ion Interaction Theory was employed for determination of thermodynamic equilibrium constants for the protonation of chloroacetate () and formation of the PdL+ complex (). Specific ion interaction coefficients were derived. 相似文献
6.
Guang-hui Cai 《Journal of mathematical chemistry》2008,43(1):375-385
Consider the partly linear regression model Y = xβ + g(t) + e where the explanatory x is erroneously measured, and both t and the response Y are measured exactly, the random error e is ρ−-mixing. Let be a surrogate variable observed instead of the true x in the primary survey data. Assume that in addition to the primary data set containing N observations of , which is ρ−-mixing data sets, an independent validation data containing n observations of is available. The exact observations on x may be obtained by some expensive or diffcult procedures for only a small subset of subjects enrolled in the study. In this
paper, inspired by Berberan-Santos et al. [J. Math. Chem. 37 (2005)101], a semiparametric method with the primary data is
employed to obtain the estimators of β and g(·) based on the least squares criterion with the help of validata. The proposed estimators are proved to be strongly consistent.
相似文献
7.
Within the Hartree-Fock framework, the spinless two-electron density function Γ (r
1, r
2) consists of direct Γdi (r
1, r
2) and exchange Γex (r
1, r
2) parts. Accordingly, the inner and outer radii in many-electron systems are rigorously separated into the direct and exchange contributions, i.e., and . It is generally shown that and , where is the usual average radius of an electron. Numerical examinations of the direct and exchange contributions for the 102 atoms
from He to Lr in their ground states find that the electron exchange works to decrease and increase . However, the exchange parts are very small and the direct parts essentially govern the inner and outer radii. 相似文献
8.
Let λ1 (G) and Δ (G), respectively, denote the largest eigenvalue and the maximum degree of a graph G. Let
be the set of trees with perfect matchings on 2m vertices, and
. Among the trees in
, we characterize the tree which alone minimizes the largest eigenvalue, as well as the tree which alone maximizes the largest
eigenvalue when
. Furthermore, it is proved that, for two trees T
1 and T
2 in
(m≥ 4), if
and Δ (T
1) > Δ (T
2), then λ1 (T
1) > λ1 (T
2). 相似文献
9.
Reena Singh Atanu Banerjee Yee Gordon Kajal Krishna Rajak 《Transition Metal Chemistry》2009,34(6):689-694
Abstract The title complexes and have been synthesized in excellent yields by reacting Co(OAc)2·4H2O with H2L1 and H2L2, respectively, in acetonitrile solution. Here, [L1]2− and [L2]2− are the deprotonated forms of N,N-bis(2-hydroxybenzyl)-N′,N′-dimethylethylenediamine and N,N-bis(2-hydroxybenzyl)-2-picolylamine, respectively. The crystal structures of and were determined by x-ray crystallography. In , each cobalt atom has distorted trigonal bipyramid geometry, while in , each cobalt atom has distorted octahedral geometry. Variable temperature magnetic moment measurements show weak antiferromagnetic
interaction in . The magnetic characterization for is in agreement with the presence of Co(II) and Co(III) centers.
Graphical Abstract The title complexes and have been synthesized in excellent yields by reacting Co(OAc)2·4H2O with dianionic N2O2 coordinating ligands. In complex 1, each cobalt atom has distorted trigonal bipyramid geometry, while in complex 2, each
cobalt atom has distorted octahedral geometry. Variable temperature magnetic moment measurements show weak antiferromagnetic
interaction in complex 1. The magnetic characterization for complex 2 is in agreement with the presence of Co(II) and Co(III)
centers.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
10.
Richard D. Adams Burjor Captain Wei Fu Mark D. Smith Lei Zhu 《Journal of Cluster Science》2006,17(1):87-95
Two new compounds Pd2Os3(CO)12
, 13 and Pd3Os3(CO)12
, 14 have been obtained from the reaction of
with Os3(CO)12 at room temperature. The products were formed by the addition of two and three
groups to the Os–Os bonds of Os3(CO)12. Compounds 13 and 14 interconvert between themselves by intermolecular exchange of the
groups in solution. Compounds 13 and 14 have been characterized by single crystal X-ray diffraction analyses.Dedicated to Professor Brian F. G. Johnson on the occasion of his retirement – 2005. 相似文献
11.
Reinaldo F. Teófilo Helder J. Ceragioli Alfredo C. Peterlevitz Leonardo M. Da Silva Flavio S. Damos Márcia M. C. Ferreira Vitor Baranauskas Lauro T. Kubota 《Journal of Solid State Electrochemistry》2007,11(10):1449-1457
The electrochemical properties of boron-doped diamond (BDD) polycrystalline films grown on tungsten wire substrates using
ethanol as a precursor are described. The results obtained show that the use of ethanol improves the electrochemistry properties
of “as-grown” BDD, as it minimizes the graphitic phase upon the surface of BDD, during the growth process. The BDD electrodes
were characterized by Raman spectroscopy, scanning electronic microscopy, cyclic voltammetry (CV), and electrochemical impedance
spectroscopy (EIS). The boron-doping levels of the films were estimated to be ∼1020 B/cm3. The electrochemical behavior was evaluated using the and redox couples and dopamine. Apparent heterogeneous electro-transfer rate constants were determined for these redox systems using the CV and EIS techniques. values in the range of 0.01–0.1 cm s−1 were observed for the and redox couples, while in the special case of dopamine, a lower value of 10−5 cm s−1 was found. The obtained results showed that the use of CH3CH2OH (ethanol) as a carbon source constitutes a promising alternative for manufacturing BDD electrodes for electroanalytical
applications. 相似文献
12.
The energy of a graph is defined as the sum of the absolute values of all the eigenvalues of the graph. Let
denote the set of trees on n vertices and diameter d,
. Yan and Ye [Appl. Math. Lett. 18 (2005) 1046–1052] have recently determined the unique tree in
with minimal energy. In this article, the trees in
with second-minimal energy are characterizedAMS Subject Classification: 05C50, 05C35 相似文献
13.
Parampaul K. Banipal Sonal Gautam Sonima Dua Tarlok S. Banipal 《Journal of solution chemistry》2006,35(6):815-844
Apparent molar volumes, V
φ, and viscosity, η, of D(+)-glucose, D(−)-fructose and sucrose in water and in 0.02, 0.05, 0.5, 1.0 and 2.0 mol·kg−1 aqueous solutions of ammonium bromide, tetraethylammonium bromide and tetra-n-butylammonium bromide have been determined at 25 °C from density and efflux time measurements by using a vibrating-tube digital densimeter and a capillary viscometer, respectively. Partial molar volumes, , at infinite dilution that were extrapolated from the V
φ data were used to obtain the corresponding transfer volumes, , for saccharides from water to different aqueous solutions of co-solutes. The Jones-Dole equation viscosity B-coefficients were obtained from the viscosity data. Positive values of were obtained for the saccharides in the presence of ammonium bromide, whereas both positive and negative values were obtained in the presence of tetraethylammonium and tetra-n-butylammonium bromides. The negative values at very low concentrations have small magnitudes. Volumetric interaction coefficients have been calculated by using the McMillan-Mayer theory and Gibbs energies of activation of viscous flow have been calculated by using Feakin’s transition-state theory equation. The parameters obtained from the volumetric and viscometric studies were used to understand various mixing effects due to the interactions between saccharides and ammonium salts in aqueous solutions. 相似文献
14.
Codon Adaptation Index (CAI), Effective Number of Codons as well as its modifications , can be used to measure gene codon bias. In this article, we prove is more efficient and unbiased than and by revisiting correlations of them with CAI in the level of individual amino acid’s codon bias. Correlations are studied
by mathematical expressions rather than statistic methods, because the latter unavoidably depend on the data set used. Additionally,
the immediate cause of correlations of with CAI (as well as those of RSCU with CAI) are also described in mathematical language. Perhaps, mathematics provides us
a new way to study correlations between biological indexes. 相似文献
15.
I. I. Guseinov 《Journal of mathematical chemistry》2008,44(1):197-205
The new formulas are obtained for complete orthonormal sets of exponential type vector orbitals of a particle with spin 1
in coordinate, momentum and four-dimensional spaces using the properties of spherical vectors and complete orthonormal scalar
basis sets of -exponential type orbitals ( -ETO), -momentum space orbitals ( -MSO) and -hyperspherical harmonics ( -HSH) introduced by the author for particles with spin s = 0, where These vector orbitals are complete without the inclusion of the continuum and, therefore, their group of transformation is
the four-dimensional rotation group of O(4). For overlap integrals over vector Slater orbitals with the same screening constant
the analytical relations in coordinate space are also derived. It should be noted that the new idea presented in this study
is the combination of spherical vectors with complete orthonormal scalar sets for radial parts of -orbitals. 相似文献
16.
Solvent effects on the dielectric dispersion of poly(vinyl pyrrolidone)-poly(ethylene glycol) blends
The complex relative dielectric function , loss tangent , complex electric modulus and alternating current electrical conductivity dispersion behaviour of liquid poly(vinyl pyrrolidone)-poly(ethylene glycol)
(PVP–PEG) blends in water, ethyl alcohol and 1,4–dioxane solvent over the entire volume mixture concentration range has been
investigated in the frequency range of 20 Hz to 1 MHz at 25 °C. The PVP–PEG blends show the dielectric dispersion corresponding
to the micro-Brownian motion of the PVP chain in the upper frequency region, whereas in the lower frequency region, dielectric
dispersion is due to ionic conduction and electrode polarization phenomena. Results show that the conductivity values of these
blends in water and dioxane can be monitored with the change in the solvent concentration, whereas it has a small variation
with ethyl alcohol concentration. The comparative dielectric dispersion shape study confirms that the chain dynamics of polymers
blend is influenced by heterogeneous interactions and solvent polar strength. 相似文献
17.
Let G be an unicycle graph and d
v
the degree of the vertex v. In this paper, we investigate the following topological indices for an unicycle graph ,
, where m ≥ 2 is an integer. All unicycle graphs with the largest values of the three topological indices are characterized.
This research is supported by the National Natural Science Foundation of China(10471037)and the Education Committee of Hunan
Province(02C210)(04B047). 相似文献
18.
P. Krishnan 《Journal of Solid State Electrochemistry》2007,11(9):1327-1334
Electrochemical oxidation of thiocyanate (SCN−) on platinum electrode in the sulfuric acid medium was studied using cyclic voltammetry, in situ UV-visible absorption measurement,
rotating ring-disc electrode voltammetry, and electrical impedance spectroscopy. Two oxidation processes are involved in the
electrochemical oxidation of SCN− in sulfuric acid medium. The adsorbed SCN− undergoes oxidation at potential values higher than 0.900 V versus saturated calomel electrode (SCE). Trithiocyanate, , is formed as a relatively stable product during the first oxidation process. The potential range of formation increases with increase in concentration of SCN−, and it is exclusively produced in the potential range of 0.550 to 1.40 V versus SCE with 1.0 M NH4SCN solution. The second oxidation process does not produce any stable product, and the products of second oxidation passivate
the electrode surface. 相似文献
19.
Li-Hua Bi Sib Sankar Mal Nadeen H. Nsouli Michael H. Dickman Ulrich Kortz Saritha Nellutla Naresh S. Dalal Manuel Prinz Georg Hofmann Manfred Neumann 《Journal of Cluster Science》2008,19(1):259-273
The mixed-valence 24-vanadophosphate
(1) has been synthesized and characterized in the solid state by IR, magnetism, EPR, XPS, and elemental analysis. Single-crystal
X-ray analysis was carried out on (Na-1), which crystallizes in the triclinic system, space group , with a = 17.168(3) ?, b = 18.1971(14) ?, c = 20.1422(13) ?, α = 114.753(3)°, β = 99.390(4)°, γ = 95.124(4)°, and Z = 2. Polyanion 1 has an unusual, open structure composed of 2 RuIIIO6 octahedra, 2 VIVO6 octahedra, 14 VVO5 square-pyramids, 8 VVO4 tetrahedra, and 2 PO4 tetrahedra which are all directly linked via edges and corners. The outer surface of 1 is decorated with six RuII(dmso)3 groups. XPS studies on Na-1 confirm the presence of 2 RuIII and 6 RuII as well as 22 VV and 2 VIV centers. Magnetic susceptibility data on Na-1 show that the VIV–RuIII pairs are coupled antiferromagnetically, with J
1 = −13 K and J
2 ∼ −3 K. We did not detect any peak in our EPR measurements on Na-1, thus supporting the conclusion that Na-1 is diamagnetic in its ground state.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
In Memoriam Prof. F. A. Cotton 相似文献
20.
The new polyoxotungstates
H2O (1),
· 28H2O (2) and
H2O (3) were synthesized in aqueous solution and characterized by IR and Raman spectroscopy, energy dispersive X-ray fluorescence and single-crystal X-ray analysis. The anions in 1 and 2 are the first structurally characterized sandwich-type polyoxoanions which contain trivalent manganese atoms. The manganese atoms are coordinated by four oxygen atoms of two
Keggin fragments and one water molecule, forming a square pyramid. The manganese(II) containing anions in 3 are linked via Mn–O–W-bonds, forming a two-dimensional network.Dedicated to Prof. M.T. Pope on the occasion of his retirement. 相似文献