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11.
Luis E. Juanicó Fabián Rinalde Eduardo Taglialavore Marcelo Molina 《Journal of Electronic Materials》2013,42(7):1789-1795
This paper presents a new thermogenerator based on moderate-temperature (up to 175°C) BiTe modules available on the open market. Despite this handicap relative to commercial thermogenerators based on high-temperature proprietary-technology PbBi modules (up to 560°C), this new design may become economically competitive due to its innovative thermal sink. Our thermal sink is based on a free-convection water loop built with standard tubing and household hot-water radiators, leading to a more practical, modular design. So, the specific cost of about 55,000 USD/kW obtained for this 120-W prototype is improved to 33,000 USD/kW for a 1-kW unit, which represents about half the price of commercial thermogenerators. Moreover, considering recently launched BiTe modules (that withstand up to 320°C), our proposition could have an even more favorable outlook. 相似文献
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Synthesis and Structure Elucidation of New Regioisomeric 2‐Alkylamino‐6‐aryl‐8,9‐dihydropyrimido[4,5‐b][1,4]diazepin‐4(7H)‐ones
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Braulio Insuasty Fabián Orozco Jairo Quiroga Rodrigo Abonía Manuel Nogueras Justo Cobo 《Journal of heterocyclic chemistry》2014,51(1):196-202
Novel 2‐Alkylamino‐6‐aryl‐8,9‐dihydropyrimido[4,5‐b][1,4]diazepin‐4(7H)‐ones 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j , 5k , 5l , 5m , 5n , 5o were prepared regioselectively by the reaction of 2‐alkylamino‐5,6‐diaminopyrimidin‐4(3H)‐ones 3a , 3b , 3c and dimethylamino propiophenones (Mannich bases) 4a , 4b , 4c , 4d , 4e , 4f . The combination of conventional heating and microwave irradiation approaches provided the possibility of working with both stable and sensitive diaminopyrimidines by controlling parameters such as reaction rates, temperature, and power of irradiation. All products were fully characterized by detailed NMR measurements. 相似文献
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Fabián H. Gaioli Edgardo T. Garcia-Alvarez Mario A. Castagnino 《International Journal of Theoretical Physics》1997,36(11):2371-2389
We introduce a ‘proper time’ formalism to study the instability of the vacuum in a uniform external electric field due to
particle production. This formalism allows us to reduce a quantum field-theoretic problem to a quantum mechanical one in a
higher dimension. The instability results from the inverted oscillator structure which appears in the Hamiltonian. We show
that the ‘proper time’ unitary evolution splits into two semigroups. The semigroup associated with decaying Gamov vectors
is related to the Feynman boundary conditions for the Green functions and the semigroup associated with growing Gamov vectors
is related to the Dyson boundary conditions. 相似文献
16.
Milan Stehlík Rastislav Potocký Helmut Waldl Zdeněk Fabián 《Computational Statistics》2010,25(3):485-503
Assessment of heavy tailed data and its compound sums has many applications in insurance, auditing and operational risk capital
assessment among others. In this paper, we compare the classical estimators (maximum likelihood, QQ and moment estimators)
with the recently introduced robust estimators of “generalized median”, “trimmed mean” and estimators based on t-score moments.
We derive the exact distribution of the likelihood ratio tests of homogeneity and simple hypothesis on the tail index of a
two-parameter Pareto model. Such exact tests support the assessment of the performance of estimators. In particular, we discuss
some problems that one can encounter when misemploying the log-normal assumption based methods supported by the Basel II framework.
Real data and simulated examples illustrate the methods. 相似文献
17.
Previous works on single bubble sonoluminescence in sulfuric acid solutions have stressed the fact that the sonoluminescence (SL) emissions are the highest ever found, but at the same time the bubble moves in orbits. We have fixed the SL bubble spatially and at the same time we have reached higher SL emissions using another harmonic acoustic signal to produce the acoustic excitation. Multiple harmonic excitation produces up to a fourfold increase in SL emissions, reaching the peak value of about 40 microW for a moving bubble and 15 microW for a nonmoving bubble. The ability to have a bright stationary bubble also opens new research opportunities. In particular, we develop a new method to measure the absolute radius evolution of the bubble that exploits this stability. 相似文献
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Semigroup Forum - To a given numerical semigroup S we associate a family of subsemigroups $$\{\partial ^nS\}$$ , $$n\in {\mathbb {N}}$$ , that permits us to understand some of the structure of S.... 相似文献
20.
The title compound crystallizes in the orthorhombic space group Pnma, with a = 7.9209(5), b = 9.818(1), c = 16.867(2) Å, and Z = 4. The structure was solved employing 1864 independent x-ray reflections with I>2(I) by Patterson and difference Fourier techniques and refined by full-matrix least-squares to R = 0.036. The trans-[CO(NH3)4(NH2CH3)Cl](ClO4)2 molecule is on a crystallographic mirror plane. The cobalt ion is in an elongated octahedral coordination with four equatorial ammonia ligands [average Co–N distance equal to 1.966(2) Å], an axial methylamine [Co–N=1.965(3)Å], and an axial chlorine ion [Co–Cl=2.2771(9)Å]. Kinetic steric effects of the complex are interpreted in terms of structural results. 相似文献