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941.
A geometrical method is suggested for representing a molecule by a smoothed region. The effective volume and surface area are calculated, which results in more adequate proportionality of interactant molecules compared to the classical van der Waals models. 相似文献
942.
《Thermochimica Acta》2004,414(2):137-143
The kinetics of nanocrystallization in amorphous TiO2 has been studied in non-isothermal conditions by DSC. It was found that this process could be well described by standard Johnson-Mehl-Avrami-Kolmogorov (JMA) model with kinetic exponent m≅1. The kinetic parameters were calculated by simultaneous analysis of experimental data taken at different heating rates. These parameters were used as a basis for prediction of crystallization kinetics in isothermal conditions. The agreement between the JMA model prediction and experimental data depends on the method of preparation of amorphous TiO2. 相似文献
943.
In a flow catalytic reactor with an autocatalytic trigger as a kinetic subsystem, the conditions have been found, in which oscillations appear. Some peculiarities of the kinetic model dynamics, where the kinetic subsystem is an autocatalytic oscillator, are investigated. 相似文献
944.
H. Bendiab G. Roux-Desgranges A. H. Roux J. -P. E. Grolier D. Patterson 《Journal of solution chemistry》1994,23(2):307-323
Densities and heat capacities of ternary systems were determined at 25°C. The ternary systems consisted of: a polar molecule (component 1) + a mixture of alkanes (components 2 and 3) of different sizes and shapes. Five such systems were studied: chlorobenzene + cyclohexane + n-heptane; chlrobenzene + cyclohexane + n-hexadecane; chlorobenze + cyclohexane + isooctane; chlorobenzene + isooctane + n-heptane; 1-chloronaphthalene + isooctane + n-heptane. The excess molar volumes and heat capacities were obtained along dilution lines by component 1 (chlorobenzene or 1-chloronaphthalene) of mixtures of components 2 and 3 (at fixed component 2 mole fraction X2). Unexpectedly the excess heat capacities C
p1(23)
E
of the pseudo-binaries {1+(2+3)} do not always fall between the two (limiting) curves of C
p12
E
and C
p13
E
corresponding to the two binaries {1+2} and {1+3}. Instead, especially for {chlorobenzene + cyclohexane + an n-alkane} the C
p1(23)
E
curves are displaced toward less negative values, even beyond the limiting values corresponding to the binaries. This correlates semi-quantitatively with the negative C
p23
E
of the binary {2+3}.Presented at the Symposium, 76th CSC Congress, Sherbrooke, Quebec, May 30-June 3, 1993, honoring Professor Donald Patterson on the occasion of his 65th birthday. 相似文献
945.
安力农的极谱测定及其电化学行为 总被引:4,自引:0,他引:4
在pH5.6,0.15mol/L磷酸盐缓冲溶液(PBS)中,得到了安力农的灵敏极谱吸附波,波的二阶导波高在2×10^-8~8×10^-6mol/L范围内与安力农的浓度成直线关系,检测下限为1×10^-8mol/L,测定出电极过程的电子传递系数a=0.43,表面电极反尖速率常数ks=3.3s^-1,安力农在汞电极上的吸附遵从Langmuir等温式,测得其吸附系数β=8.1×10^5。 相似文献
946.
H. M. J. Goldschmidt N. C. V. Péquériaux J. De Jongh-Leuvenink 《Accreditation and quality assurance》2002,7(11):468-472
The European Foundation for Quality Management (EFQM) integral quality management model covers nine issues: five so-called
enabler criteria and four so-called result-oriented criteria. The first enabler criterion concerns leadership and covers all
kind of strategic management aspects. However, directly or indirectly, the leadership of the board of directors or its individual
members is characterized and scored. An even more explicate technique, originated in a totally different way, is the 360°
feedback evaluation method. In this paper both methods are compared and practiced on various individuals. A checklist was
developed to facilitate scoring in the EFQM leadership submodel. Both methods, although from a different origin, could be
linked easily, covered very similar aspects and gave results that were in excellent agreement with each other. The scoring
showed almost identical results, supporting in large the use of the integral EFQM model.
Received: 25 May 2002 Accepted: 17 July 2002
Presented at the European Conference on Quality in the Spotlight in Medical Laboratories, 7–9 October 2001, Antwerp, Belgium
Correspondence to H. M. J. Goldschmidt 相似文献
947.
Krzysztof Kurzak Iwona Kuźniarska-Biernacka Barbara Kurzak Julia Jezierska 《Journal of solution chemistry》2001,30(8):709-731
As a part of our general interest in the UV-Vis spectroscopy of multidentate mixed-donor ligands, the (salicylideneethylenediamine)Cu(II) complex has been prepared and characterized by elemental analyses, solubility in common solvents, molar conductivities, and ultraviolet (UV), and visible (Vis) spectroscopy. The combined results of spectrophotometric measurements and EPR spectra, as well as known the X-ray structure for solids, were used to determine the structure of the investigated complex in solutions. The spectra of [Cu(salen)] (H2salen = salicylideneethylenediamine), were measured in various solvents at room temperature, resolved by Gaussian analysis, and angular overlap model (AOM) treated in C
2v symmetry. Because of overparametrization problems, the bis(salicylaldehyde)Cu(II) complex has been characterized and AOM treated. The results of this have been used for AOM studies of [Cu(salen)]. The effect of the solvents upon the - and -bonding ligand abilities is discussed. 相似文献
948.
Jacob G. Reynolds 《Silicon Chemistry》2007,3(5):267-269
The Partial Charge Model was developed to predict the hydroxylation, polymerization, and precipitation of ions. The purpose
of this study is to evaluate the Partial Charge Model for describing the polymerization of silica in aqueous solutions. The
Partial Charge Model predicts the stability of ions and complexes based on the assumption that the stable species will have
the same electronegativity as the mean electronegativity of the solution. The silica system was chosen for model validation
because of the rare availability of self-consistent thermodynamic data on many dissolved but polymerized silicate anions,
including both linear and cyclical species. The electronegativity of each species was calculated using the Partial Charge
Model and the results were plotted against the stability constants for the ions. The silicate anions segregated into groups
on the plot based on the number of charges per silicon atom in the polymer. Plots of the log of the stability constant versus
the change in electronegativity produced a linear relationship for the silica polymers containing one negative charge per
silicon atom, which resulted in an r
2 of 0.9978. Thus, the Partial Charge Model successfully describes the thermodynamics of silica polymerization in aqueous solution
for species that are sufficiently alike, but was not accurate for all silica species. 相似文献
949.
Thermodynamics of the interaction between Ni2+ and human growth hormone (hGH) were determined at 27 °C in Nail solution by isothermal titration calorimetry. A new method to predict protein penetration and the effect of metal ions on the stability of proteins is introduced. The new solvation model was used to reproduce the enthalpies of Ni2+-hGH interaction over the whole range of Ni2+ concentrations. The solvation parameters recovered from the new equation, attributed to the structural change of hGH and its biological activity. 相似文献
950.
A relationship between the X-H (X = N, O, C, and so on) equilibrium bond length in a Morse oscillator and the X-H stretching overtone frequency shifts is obtained theoretically. We use the equation to discuss the empirical linear relationships that have been proposed for heterocyclics, alkanes and fluorinated benzenes. On the other hand, a unified relationship between the X-H bond angles and the experimental quantities (ω(?) and the coupling strength λ) is also presented for XH2, XH, and XH4 molecules or molecular fragments. Calculations of X-H bond angles for a number of molecules show that the results from our equations are in excellent agreement with the experimental values. Also we can extract the information of relative magnitude of bond coupling force field. 相似文献