排序方式: 共有19条查询结果,搜索用时 109 毫秒
1.
The apparent molar heat capacities of dilute aqueous solutions of acetic, propanoic and succinic acid and sodium salts of the two monofunctional acids were measured at 300 Kp,2
o
. After subtracting the heat capacity of a point mass, the remaining heat capacity was successfully decomposed into functional group contributions at all temperatures. Together with the results of our previous paper on alcohols and diols the heat capacity contributions of the CH2, CH3, OH, COOH, (COOH)2, and COONa groups are now available and these allow reasonably accurate predictions of the heat capacities of all compounds composed of these groups in this temperature range. 相似文献
2.
Americo Inglese Fabio Mavelli Rosario De Lisi Stefania Milioto 《Journal of solution chemistry》1997,26(3):319-336
Densities of binary mixtures of polar organic solvents with alcohols were measured at 25‡C. The solvents studied were N,N-dimethylformamide,
dimethylsulfoxide, and formamide while alcohols were butanol, pentanol, hexanol, and 1,4-butanediol. Density measurements
of hydrocarbons (from pentane to dodecane and some heptane isomers) + N,N-dimethylformamide were also performed. From these
data the apparent molar volumes of alcohols and hydrocarbons as functions of concentration were calculated. The standard partial
molar volumes were obtained by extrapolation to infinite dilution and are discussed in terms of group contributions. 相似文献
3.
The present work offers new equations for phase evaluation in measurements. Several phase shifting equations with an arbitrary but constant phase shift between captured intensity signs are proposed. The equations are similarly derived as the so-called Carré equation. The idea is to develop a generalization of Carré equation that is not restricted to four images. Errors and random noise in the images cannot be eliminated, but the uncertainty due to their effects can be reduced by increasing the number of observations. An experimental analysis of the mistakes of the technique was made, as well as a detailed analysis of mistakes of the measurement. The advantages of the proposed equation are its precision in the measures taken, speed of processing and the immunity to noise in signs and images. 相似文献
4.
Surface Tension, Heat Capacity, and Volume of Amphiphilic Compounds in Formamide Solutions 总被引:1,自引:0,他引:1
Americo Inglese Pietro D'Angelo Rosario De Lisi Stefania Milioto 《Journal of solution chemistry》1998,27(5):403-424
Density measurements of sodium dodecyl sulfate (SDS), sodium decyl sulfate (SDeS), sodium octyl sulfate(SOS), and sodium hexyl sulfate(SHS) in formamide (FA) as functions of the surfactant concentrations were carried out at 25°C. For SDS in FA, additional density measurements at 35 and 60°C and surface tension and specific heat capacity measurements at 25°C were also performed. From density and specific heat capacity data, the apparent molar volume and heat capacity of the surfactants as functions of concentration were calculated. The surface excess of SDS at the solution–air interface was also determined from the surface tension measurements using the Gibbs adsorption equation. Under our experimental conditions, none of the experimental results evidence micelle formation. In addition, volumetric studies of the hexanol–SDS–FA ternary system at 25°C evidence only interactions between the dispersed surfactant and alcohol. 相似文献
5.
Juan Pedro Rojas-Armas Jorge Luis Arroyo-Acevedo Miriam Palomino-Pacheco Jos Manuel Ortiz-Snchez James Calva Hugo Jesus Justil-Guerrero Americo Castro-Luna Norma Ramos-Cevallos Edwin Csar Cieza-Macedo Oscar Herrera-Calderon 《Molecules (Basel, Switzerland)》2022,27(6)
Annona muricata leaves are traditionally used as an anticancer plant in the world. The aim of this study was to evaluate the ameliorative effect of the essential oil from Annona muricata leaves (EOAm) in an experimental model of breast cancer and to determine the volatile constituents with gas chromatography-mass spectrometry (GC-MS). Thirty female rats were assigned to five groups: the control group; the DMBA (7,12-dimethylbenz[α]anthracene) group; and three groups received daily EOAm doses of 50, 100, and 200 mg/kg/day, plus DMBA, respectively. After 13 weeks of treatment, tumors were analyzed pathologically and biochemical markers in serum were noted. As a result, in GC-MS analysis, 40 compounds were identified and 4 of them were abundant: Z-caryophyllene (40.22%), followed by α-selinene (9.94%), β-pinene (8.92%), and β-elemene (7.48%). Furthermore, EOAm in a dose-dependent form produced a reduction in tumor frequency and the accumulated tumor volume was reduced by 50% and 71% with doses of 100 and 200 mg/kg, respectively. Serum levels of reduced glutathione (GSH) increased and malondialdehyde (MDA) decreased significantly compared to the DMBA group. Serum levels of vascular endothelial growth factor (VEGF) decreased significantly from 70.75 ± 7.15 pg/mL in the DMBA group to 46.50 ± 9.00 and 34.13 ± 11.50 pg/mL in groups treated with doses of 100 and 200 mg/kg, respectively. This study concludes that the EOAm leaves showed an ameliorative effect in a murine model of breast cancer. 相似文献
6.
A method is proposed for using the Picker microcalorimeter without programmation of the flow rates of the reactant liquids. From the measurements of the three systems (carbon tetrachloride+benzene, +n-heptane and +cyclopentane) it is shown that the excess enthalphy curves obtained point by point are better defined than those obtained directly in the scanning mode, especially in the dilute regions. 相似文献
7.
Pedro Americo Almeida Magalhaes Perrin Smith Neto Clovis Sperb de Barcellos 《Optical Review》2009,16(4):432-441
The present work offers new algorithms for phase evaluation in optics measurements. Several phase-shifting algorithms with
an arbitrary but constant phase-shift between captured intensity frames are proposed. The algorithms are derived similarly
to the so called Carre algorithm. The idea is to develop a generalization of Carre that is not restricted to four images.
Errors and random noise in the images cannot be eliminated, but the uncertainty due to its effects can be reduced by increasing
the number of observations. The advantages of the proposed algorithm are its precision in the measures taken and immunity
to noise in images. 相似文献
8.
Americo Inglese Maurizio Castagnolo Angelo Dellatti Angelo de Giglio 《Thermochimica Acta》1981,44(1):77-87
Molar excess heat capacities at constant pressure, CEp, of binary liquid mixtures chloroform + oxolane, chloroform + 1,3-dioxolane, chloroform + oxane, and chloroform + 1,4-dioxane have been determined at 298.15 K from measurements of volumetric heat capacities in a Picker flow microcalorimeter. A precision of ±0.04 J K?1 mole? was achieved by using the stepwise procedure. Experimental molar excess heat capacities are compared with values derived from HE results at different temperatures. Excess molar volumes, VE, for the same systems at 298.15 K have been determined by measuring the density of the pure liquids and solutions with a high-precision digital flow densimeter. 相似文献
9.
Nonlinear Dynamics - This work deals with the solution of a non-convex optimization problem to enhance the performance of an energy harvesting device, which involves a nonlinear objective function... 相似文献
10.
Richard S. Herrick Christopher J. Ziegler Roshinee Costa Americo Gambella 《Journal of organometallic chemistry》2009,694(24):3929-3934
The title compounds were prepared in good yield by treatment of Re(CO)5Cl or [Re(CO)3(H2O)3]Br with sodium dimethyldithiocarbamate hydrate (NaS2CNMe2·H2O) and a neutral ligand yielding eight Re(CO)3(S2CNMe2)(L) derivatives: L = NH31, pyridine (py) 2, imidazole (im) 3, pyrazole (pz) 4, triphenylphospine (PPh3) 5, 1,3,5-triaza-7-phosphaadamantane (PTA) 6, t-butyl isocyanide (t-BuNC) 7, and cyclohexyl isocyanide (CyNC) 8. The resulting new complexes were characterized by 1H and 13C NMR and infrared spectroscopy. Each was also structurally elucidated by X-ray crystallography. General structural features in all eight compounds were similar. The orientation of the three single-faced ligands, py, im and pz, demonstrates an interaction with the filled π orbital of the dithiocarbamate. Compounds were tested for stability under conditions that mimic physiological conditions; 1-4 quickly decomposed, 7 and 8 decomposed over 24 h while 5 and 6 were stable. 相似文献