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排序方式: 共有72条查询结果,搜索用时 15 毫秒
1.
K. Rohlena K. Mašek E. G. Balabanova I. Paulička 《Czechoslovak Journal of Physics》1988,38(6):622-637
Systematic calculations of maximum inversion were performed for iodine photodissociation laser in dependence on the mixture composition. The flash-lamp radiation was modelled as emanating from an optically thin Xe plasma. Duration of the pumping pulse is about 300 s. The sensitivity of the model to the values of kinetic constants was also tested. 相似文献
2.
B. A. Trofimov S. E. Korostova A. I. Mikhaleva L. N. Balabanova A. N. Vasil'ev 《Chemistry of Heterocyclic Compounds》1977,13(2):172-173
The hydrogenation of 1-vinylpyrroles over Raney nickel in ethanol at 50–90°C proceeds exclusively at the 1-vinyl group and leads to the formation of 1-ethylpyrroles in 80–90% yields. The IR and PMR spectra are presented.Translated from Khimiya Geterotsilicheskikh Soedinenii, No. 2, pp. 215–216, February, 1077. 相似文献
3.
F. K. Velichko L. V. Balabanova T. T. Vasil'eva O. P. Bondarenko G. A. Shvekhgeimer 《Russian Chemical Bulletin》1988,37(3):610-612
1. | The position of the charge transfer band in the charge transfer complexes of ferrocene derivatives with CH2I2, CHI3, and CI4 is more a function of the nature of the polyiodomethane than of the nature of the substituent in the ferrocene molecule. |
2. | The ferrocene ionization potential was used to calculate the position of this band when experimental determination was difficult. |
4.
The production of ultrafine silica particles is examined by modelling the processes in a flow plasma reactor. The model is based on the authors' experimental data on silica sand processing by use of thermal arc plasma. The free-molecular coagulation is assumed to be the dominant process for particle growth. This is carried out at fast cooling of the vapour, during its mixing with oxygen. The particle size distribution functions are calculated, and the influence of the chemical monomer generation and the mixing on their behavior is investigated. Comparison of the calculated and the experimental mean particle size is made.List of symbols
C
nl
collision frequency function, cm3/s
-
d
m
mean median diameter, nm
-
F
LN(d)
integral form of the particle size distribution function,%
-
g(t)
mixing function
-
k
Boltzmann's constant
-
k
1,k,k
rate coefficients, cm3/s
-
k
2,k
3
rate coefficiens, cm6/s
-
m
mass of the monomer, g
-
M
number of groups
-
T
absolute temperature, K
-
T
0
temperature of the hot vapour, K
-
T
E
temperature of SiO2 condensation, K
-
t
time, s
-
t
m
mixing time, s
-
t
c
colling time, s
-
z
0
monomer concentration, cm–3
-
z
n
,z
l
concentrations of particles in groups, cm–3
- z
n
total number concentration of particles (n=0, 1, M), cm–3
-
z
n
/(z
n
)(log d
n+1
–logd
n)
differential form of particle size distribution function
-
w
i
reaction rates (i=1, 2, 3), cm–3/s
- ,
cooling rates, K/s
-
coefficient of proportionality
- SiO
conversion rate of SiO,%
-
coefficient determined from the cooling rate, s–1
-
mass density of the particles, g/cm3
-
standard deviation
The authors gratefully acknowledge Prof. L. S. Polak from the Institute of Petrol Chemical Synthesis, Russian Academy of Science, for helpful discussions. 相似文献
5.
6.
A. Ya. Samuilov S. V. Nesterov F. B. Balabanova Ya. D. Samuilov A. I. Konovalov 《Russian Journal of Organic Chemistry》2013,49(7):968-973
The mechanisms of the reactions of methyl isocyanate with phenol monomer and linear dimer were studied at the B3LYP/6-311++G(df,p) level of theory, and the results were compared with those obtained for the reactions with methanol associates. All the examined reactions involve asymmetric concerted transition states. The addition of phenol is electrophilic, whereas the addition of methanol is nucleophilic. The formation of H-complexes with phenol and methanol molecules increases not only electron-donating power but also gasphase acidity and basicity. 相似文献
7.
A. Ya. Samuilov A. R. Valeev F. B. Balabanova Ya. D. Samuilov A. I. Konovalov 《Russian Journal of Organic Chemistry》2013,49(1):28-33
Thermal decomposition of urea in ethylene glycol with formation of isocyanic acid and ammonia was studied at the B3LYP/6-311++G(df,p) level of theory. The decomposition process is efficiently catalyzed by monomeric and dimeric forms of ethylene glycol. Ethylene glycol dimer formed via intermolecular hydrogen bonding is a stronger acid than the monomeric species, which is responsible for the higher catalytic activity of the former. Ethylene glycol associates efficiently catalyze addition of ammonium to isocyanic acid in the synthesis of ethylene carbonate. 相似文献
8.
Mathilde Montibus Xavier Vitrac Vronique Coma Anne Loron Laetitia Pinson-Gadais Nathalie Ferrer Marie-Noëlle Verdal-Bonnin Julien Gabaston Pierre Waffo-Tguo Florence Richard-Forget Vessela Atanasova 《Molecules (Basel, Switzerland)》2021,26(2)
Fusarium graminearum is a fungal pathogen that can colonize small-grain cereals and maize and secrete type B trichothecene (TCTB) mycotoxins. The development of environmental-friendly strategies guaranteeing the safety of food and feed is a key challenge facing agriculture today. One of these strategies lies on the promising capacity of products issued from natural sources to counteract crop pests. In this work, the in vitro efficiency of sixteen extracts obtained from eight natural sources using subcritical water extraction at two temperatures was assessed against fungal growth and TCTB production by F. graminearum. Maritime pine sawdust extract was shown to be extremely efficient, leading to a significant inhibition of up to 89% of the fungal growth and up to 65% reduction of the mycotoxin production by F. graminearum. Liquid chromatography/mass spectrometry analysis of this active extract revealed the presence of three families of phenolics with a predominance of methylated compounds and suggested that the abundance of methylated structures, and therefore of hydrophobic compounds, could be a primary factor underpinning the activity of the maritime pine sawdust extract. Altogether, our data support that wood/forest by-products could be promising sources of bioactive compounds for controlling F. graminearum and its production of mycotoxins. 相似文献
9.
The oxidation of ascorbic acid (AA) and dopamine (DA) is studied on non-modified and copper crystal-modified poly(3,4-ethylenedioxythiophene) (PEDOT)-coated electrodes. Both oxidation reactions are studied for different thickness of the polymer layers. For several microns thick PEDOT layers both PEDOT and Cu-modified PEDOT show the largest currents. A stable voltammetric response for AA oxidation is observed together with a linear dependence of the peak currents on concentration in the 0.3 to 6.0 mM range. For DA oxidation, however, a gradual loss of electroactivity is found with increasing number of voltammetric scans and concentration. This problem is overcome by using thinner (<1 µm) polymer layers. In the presence of both AA and DA, the Cu-modified PEDOT-coated electrodes provide better selectivity with respect to DA in comparison to non-modified PEDOT due to partial suppression of the AA oxidation currents. Thin PEDOT layers modified with electrodeposited Cu crystals show a stable and sensitive response for DA oxidation in the micromolar concentration range. A linear dependence of the voltammetric peak currents is found in a wide concentration range (from 6 to about 200 µM) of DA in the presence of a large excess (1 mM concentration) of AA. The sensitivity is 0.013 µA?µM-1. 相似文献
10.