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排序方式: 共有658条查询结果,搜索用时 31 毫秒
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Victor V. Dodonov Margarita A. Man’ko Vladimir I. Man’ko Apostol Vourdas 《Journal of Russian Laser Research》2007,28(5):404-428
A brief review of the history of ten workshops/conferences on “Squeezed States and Uncertainty Relations” and main achievements
in the related fields of quantum physics for the period from 1991 to 2007 are presented. 相似文献
4.
Esperanza Salfrn Carlos Seoaneb Margarita Surez Yamila Verdecia Amaury Alvarez Estael Ochoa Roberto Martínez‐Alvarez Nazario Martín 《Journal of heterocyclic chemistry》2004,41(4):509-516
Novel 4‐amino‐6‐aryl‐2‐phenylpyrimidine‐5‐carbonitriles have been prepared in one step procedure from the readily available 4‐aryl‐2‐amino‐3‐cyano‐5,6,7,8‐tetrahydro‐7,7‐dimethyl‐5‐oxo‐4H‐benzopyrans. The mass spectroscopy study under EI conditions shows molecular peaks with high intensity corresponding to the loss of benzonitrile from the C2 position of the pyrimidine ring. Semiempirical (AMI and PM3) and ab initio HF/6–31G* calculations reveal a favored distorted geometry where the three rings are not in the same plane. 相似文献
5.
Margarita Valero Silvia M. B. Costa José R. Ascenso M. Mercedes Velázquez Licesio J. Rodríguez 《Journal of inclusion phenomena and macrocyclic chemistry》1999,35(4):663-677
The inclusion of the anti-inflammatory drug, Nabumetone, in -, - and hydroxypropyl--cyclodextrin (CDs) is studied using UV-VIS absorption and steady-state fluorescence emission. Binding constants and thermodynamic parameters of complex formation are determined by spectrofluorimetry. The inclusion phenomena of Nabumetone with the three cyclodextrins is compared with that of the well known similar anti-inflammatory drug Naproxen. In the case of Nabumetone pronounced differences are observed in the complexation process with each cyclodextrin whereas the respective Naproxen complexes are nearly identical. 1H-NMR experiments show that the inclusion process in Nabumetone can occur either through the substituents in the -2 (butanone) or -6 (methoxy) positions in the naphthalene ring. 相似文献
6.
Molecular dynamics simulations of monolayers of surfactant mixtures at the air/water interface were performed where the binary mixture was composed of sodium dodecyl sulfate (SDS) and dodecanol molecules. At the same ratio of SDS and dodecanol molecules, two monolayer mixtures were prepared. In the first monolayer, all the dodecanol molecules were placed together in the center of the simulation box, whereas in the second monolayer, those molecules were uniformly distributed in the surface area in such a way that they were far from each other. Simulations of both systems indicate that the dodecanol tails in the first monolayer are straighter and more ordered than those in the second monolayer. From the present results, we observed new insights of how the different molecules should array or distribute at the interface in real systems. Finally, studies of the interfacial water around the different surfactants were also analyzed, showing that they are closer to the polar headgroups of dodecanol than to the SDS headgroups. 相似文献
7.
Margarita Valero Brígida Esteban Rafael Peläez Licesio J. Rodrïguez 《Journal of inclusion phenomena and macrocyclic chemistry》2004,48(3-4):157-163
The aim of the present study was to investigate the effect of the presence of thewater-soluble polymer polyvinylpyrrolidone (PVP) MW = 24000 g/mol, on thecomplexation of the phototoxic anti-inflammatory drug naproxen, in its sodiumsalt form, with hydroxypropil-β-cyclodextrin (HP-β-CD). The datashown that the polymer interacts with the free naproxen and with thenaproxen:HP-β-CD inclusion complex. The presence of different proportions of PVP, in the 0–1%(w/w) rangesystematically increased the Kapp of the naproxen:HP-β-CD inclusioncomplex formation. The cause of this increase is that the polymer interactswith the HP-β-CD with a binding constant of K2 = 29000 ± 53 M-1; and with the naproxen:HP-β-CD inclusion complex, to givea ternary complex naproxen:HP-β-CD:PVP. The binding constant of thisprocess was K3 = 5350 ± 1 M-1. NMR data revealed that in the ternary system, PVP is outside of the cyclodextrin, and therefore must be wholly or partially recovering the naproxen:HP-β-CD inclusion complex. 相似文献
8.
Pulverized coal plasma gasification 总被引:11,自引:0,他引:11
R. A. Kalinenko A. P. Kuznetsov A. A. Levitsky V. E. Messerle Yu. A. Mirokhin L. S. Polak Z. B. Sakipov A. B. Ustimenko 《Plasma Chemistry and Plasma Processing》1993,13(1):141-167
A number of experiments on the plasma-vapor gasification of brown coals of three types have been carried out using an experimental plant with an electric-arc reactor of the combined type. On the basis of the material and heat balances, process parameters have been obtained: the degree of carbon gasification (c), the level of sulfur conversion into the gas phase (s), the synthesis gas concentration (CO+Hz) in the gaseous products, and the specific power consumption for the gasification process. The degree of gasification was 90.5-95.0%, the concentration of the synthesis gas amounted to 84.7–85.7%, and the level of sulfur conversion into the gas phase was 94.3–96.7%. Numerical study of the process of plasma gasification of coals was carried out using a mathematical model of motion, heating, and gasification of polydisperse coal particles in an electric-arc reactor of the combined type with an internal heat source (arc). The initial conditions for a conjugate system of nonlinear differential equations of the gas dynamics and kinetics of a pulverized coal stream interacting with the electric arc and oxidizer (water vapor) agree with the initial conditions of the experiments. The computation results satisfactorily correlate with the experimental data. The mathematical model can be used for the determination of reagent residence time and geometrical dimensions of the plasma reactor for the gasification of coals.Nomenclature
c
i
volume concentration of components (kmol m–3)
-
x
longitudinal coordinate (m)
-
f
i
source members, determined by variation of the ith component due to chemical reactions in unit volume in unit time (kmol m–3s–1)
-
velocity (m s–1)
-
M
s
ash mass in one particle (kg)
-
C
D
particle drag coefficient
-
3.14
-
r
s
particle radius (m)
-
d
particle diameter (m)
-
density (kg m–3)
-
C
p
heat capacity of components (J molt– K–1)
-
Q
j
thermal effect of reaction (J kmol–1)
- Ej
activation energy of reaction
-
N
l
volume concentration of particles of thelth fraction (m–3)
-
T
temperature (K)
-
emissivity factor of coal particles
-
5.67 × 10–8, blackbody emissivity coefficient (W m–2 K–4)
-
P
pressure (Pa)
-
S
reactor cross section (m2)
-
D
reactor diameter (m)
-
V
reactor volume (m3)
-
L
R
reactor length (m)
-
F
W
friction force on the wall (N)
-
f
g
friction coefficient
-
residence time (s)
- Nu
Nusselt number
- Re
Reynolds number
- Pr
Prandtl number
-
thermal conductivity of gas (J m– s–1 K–1)
-
R
8.3 × 103, universal gas constant (J kmol K–1)
- µ
i
molecular mass of component (kg kmol–1)
-
dynamic viscosity coefficient of gas (kg m–1 s–1)
-
thermal efficiency of plasma reactor
- qarc
specific heat flow from arc (W m–3)
-
P
1
heat supplied in vapor at T = 405 K (W)
-
P
2
heat loss to wall (W)
-
P
3
heat loss in the gas and slag separator chamber (W)
-
P
4
heat loss in the synthesis gas oxidation chamber (W)
-
P
5
heat loss in the slag catcher (W)
-
P
6
heat carried away in the off-gas (W)
- P
heat input of arc (W)
-
P
arc
electric power of arc (W)
- Qsp
specific power consumption (kw Hr kg–1)
-
d
w
specific heat flow to wall (W m–2)
-
c
degree of carbon gasification (%)
-
s
level of sulfur conversion into gas phase (%) 相似文献
9.
Chekmarev DS Lazareva MI Zatonsky GV Maskaev AV Caple R Smit W 《The Journal of organic chemistry》2002,67(23):7957-7967
Data on the selectivity of the Lewis acids induced transformations of the title compounds are presented, and the routes leading to formation of products containing either cyclohexane or 1,3-diene units are described. 相似文献
10.
Novella F. Kazanskaya Margarita A. Manenkova Nikolay L. Eremeev 《Applied biochemistry and biotechnology》1996,61(1-2):57-65
The coupling of photosensitive reagents has been carried out with the goal of obtaining the predetermined distribution of binding sites either for “surface” or “spacial” immobilization of biomacromolecules. The correlation holds between light intensity and the number of readant groups emerged in a matrix. 相似文献