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排序方式: 共有262条查询结果,搜索用时 31 毫秒
171.
Željko D. Čupić Ljiljana Z. Kolar‐Anić Slobodan R. Anić Stevan R. Maćešić Jelena P. Maksimović Marko S. Pavlović Maja C. Milenković Itana Nuša M. Bubanja Emanuela Greco Stanley D. Furrow Rinaldo Cervellati 《Helvetica chimica acta》2014,97(3):321-333
The intermittency or intermittent bursting as the type of dynamic state when two qualitatively different behaviors replace one another randomly during the course of the reaction, although all the control parameters remain constant, is found in the Briggs? Rauscher oscillating system moderated by a very small amount of phenol. Within a range of phenol concentrations, the oscillation amplitude is diminished considerably, and after oscillations cease, they repeat intermittently, giving several bursts of oscillations. For the concentrations used here, the range of phenol concentrations where intermittent bursting oscillations occur in a closed reactor is ca. 1.8×10?5 to 3.6×10?5 M . Bursting also occurs in an open reactor and can be sustained indefinitely at 5.53×10?5 M concentration. The intermittent bursting behavior is robust, and can be achieved at a variety of conditions. 相似文献
172.
Rinaldo M. Colombo Paola Goatin Fabio S. Priuli 《Nonlinear Analysis: Theory, Methods & Applications》2007
This note is devoted to the study of traffic flow models that develop phase transitions. From the analytical point of view, this is a first example of a well posedness result for conservation laws developing phase transitions, which is independent from the number of phase boundaries in the initial data or in the solutions. We consider below the Cauchy problem as well as the problem with boundaries. 相似文献
173.
This paper considers the Cauchy problem for a conservation law with a variable unilateral constraint, its motivation being, for instance, the modeling of a toll gate along a highway. This problem is solved by means of nonclassical shocks and its well posedness is proved. Then, the solutions so obtained are shown to coincide with the limits of the classical solutions to suitable conservation laws with discontinuous flux function that approximate the constrained problem. 相似文献
174.
Abstract We give rigorous results on the analytical properties of multilane traffic flow models based on hyperbolic balance laws.
Keywords: Traffic flows, Hyperbolic conservatin laws, Operator splitting method 相似文献
175.
ATRP/OMRP/CCT Interplay in Styrene Polymerization Mediated by Iron(II) Complexes: A DFT Study of the α‐Diimine System
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Prof. Rinaldo Poli Prof. Michael P. Shaver 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(52):17530-17540
A DFT study of various model systems has addressed the interference of catalytic chain transfer (CCT) as a function of the R2 substituent in the atom‐transfer radical polymerization (ATRP) of styrene catalyzed by [FeCl2(R1N?C(R2)?C(R2)?NR1)] complexes. All model systems used R1=CH3 in place of the experimental Cy and tBu substituents and 1‐phenylethyl in place of the polystyrene (PS) chain. A mechanistic investigation of 1) ATRP activation, 2) radical trapping in organometallic‐mediated radical polymerization (OMRP), and 3) pathways to the hydride CCT intermediate was conducted with a simplified system with R2=H. This study suggests that CCT could occur by direct hydrogen‐atom transfer without any activation barrier. Further analysis of more realistic models with R2=p‐C6H4F or p‐C6H4NMe2 suggests that the electronic effect of the aryl para substituents significantly alters the ATRP activation barrier. Conversely, the hydrogen‐atom‐transfer barrier is essentially unaffected. Thus, the greater ATRP catalytic activity of the p‐NMe2 system makes the background CCT process less significant. The DFT study also compares the [FeCl2(R1N?C(R2)?C(R2)?NR1)] systems with a diaminobis(phenolato) derivative for which the CCT process shows even greater accessibility but has less incidence because of faster ATRP chain growth and interplay with a more efficient OMRP trapping. The difference between the two systems is attributed to destabilization of the FeII catalyst by the geometric constraints of the tetradentate diaminobis(phenolato) ligand. 相似文献
176.
Dr. Fabio Carniato Dr. Chiara Bisio Dr. Rinaldo Psaro Prof. Leonardo Marchese Dr. Matteo Guidotti 《Angewandte Chemie (International ed. in English)》2014,53(38):10095-10098
A NbV‐containing saponite clay was designed to selectively transform toxic organosulfur chemical warfare agents (CWAs) under extremely mild conditions into nontoxic products with reduced environmental impact. Thanks to the insertion of NbV sites within the saponite framework, a bifunctional catalyst with strong oxidizing and acid properties was obtained. Remarkable activity and high selectivity were observed for the oxidative abatement of (2‐chloroethyl)ethyl sulfide (CEES), a simulant of sulfur mustard, at room temperature with aqueous hydrogen peroxide. This performance was significantly better compared to a conventional commercial decontamination powder. 相似文献
177.
178.
The theory of hyperbolic conservation laws has been successfully applied to the study of vehicular traffic flows. We present here some models showing phase transitions, that in terms of traffic flows correspond to two distinct behaviors, free or congested. 相似文献
179.
We introduce an interacting particle system to model the emergence of drug-resistant diseases, one of the most serious health problems in modern society. We are interested in diseases for which a natural strain may mutate into a drug-resistant strain. This happens, for instance, when antibiotics are misused. The main result of our analysis is that with an efficient drug against the natural strain, if there is even a small chance that the natural strain mutates into the drug-resistant one, then there will eventually be an outbreak of the drug-resistant strain throughout the population. In that case the natural strain disappears and is replaced by the drug-resistant strain. The disturbing part of this is that an efficient treatment of the natural strain gives an edge to the drug-resistant strain. 相似文献
180.
Summary In this work we consider thermal and electric conduction in rigid materials with memory. The implications due to the invariance
of the entropy production under time-reversal are examined in detail. Some interesting conditions on the relaxation functions
of the heat flux, the electric current and the internal energy density are discussed.
This work was supported by the ? Gruppo Nazionale per la Fisica Matematica ? of C.N.R.
Entrata in Redazione il Io ottobre 1973. 相似文献
Sunto In questo lavoro gli Autori studiano la conduzione termica ed elettrica in un materiale rigido con memoria. Vengono esaminate in dettaglio le conseguenze, dovute alla invarianza della produzione entropica per inversione temporale, sulle funzioni di rilassamento per il flusso di calore, la densità di corrente elettrica e la densità di energia interna.
This work was supported by the ? Gruppo Nazionale per la Fisica Matematica ? of C.N.R.
Entrata in Redazione il Io ottobre 1973. 相似文献