排序方式: 共有327条查询结果,搜索用时 15 毫秒
191.
Ebrahim Soleimani Somayeh Ghorbani Mojtaba Taran Afshin Sarvary 《Comptes Rendus Chimie》2012,15(11-12):955-961
An environmentally friendly and simple method for the synthesis of some 4,4′-(arylmethylene)bis(3-methyl-1H-pyrazol-5-ol) derivatives via a one-pot pseudo five-component reaction of hydrazine hydrate, ethyl acetoacetate and aldehydes in water using pyridine trifluoroacetate or acetic acid at 70 °C is reported. 相似文献
192.
Among a comprehensive scope of mitigation measures for climate change, CO2 capture and sequestration (CCS) plays a potentially significant role in industrialised countries. In this paper, we develop
an analytical real options model that values the choice between two emissions-reduction technologies available to a coal-fired
power plant. Specifically, the plant owner may decide to invest in either full CCS (FCCS) or partial CCS (PCCS) retrofits
given uncertain electricity, CO2, and coal prices. We first assess the opportunity to upgrade to each technology independently by determining the option value
of installing a CCS unit as a function of CO2 and fuel prices. Next, we value the option of investing in either FCCS or PCCS technology. If the volatilities of the prices
are low enough, then the investment region is dichotomous, which implies that for a given fuel price, retrofitting to the
FCCS (PCCS) technology is optimal if the CO2 price increases (decreases) sufficiently. The numerical examples provided in this paper using current market data suggest
that neither retrofit is optimal immediately. Finally, we observe that the optimal stopping boundaries are highly sensitive
to CO2 price volatility. 相似文献
193.
Somayeh Zare Zahra Raissi Hosein Mohammadzadeh Behrouz Mirza 《The European Physical Journal C - Particles and Fields》2012,72(9):1-12
We consider a boson gas on the stretched horizon of the Schwartzschild and Kerr black holes. It is shown that the gas is in a Bose?CEinstein condensed state with the Hawking temperature T c =T H if the particle number of the system be equal to the number of quantum bits of space-time $N \simeq{A}/{l_{p}^{2}}$ . Entropy of the gas is proportional to the area of the horizon (A) by construction. For a more realistic model of quantum degrees of freedom on the horizon, we should presumably consider interacting bosons (gravitons). An ideal gas with intermediate statistics could be considered as an effective theory for interacting bosons. This analysis shows that we may obtain a correct entropy just by a suitable choice of parameter in the intermediate statistics. 相似文献
194.
The convective heat transfer coefficients resulting from a slot jet on a plane surface have been estimated by using the real measured temperatures in the plate and inverse method. In this study, the inverse method used the conjugate gradient method with an adjoint equation. Distributions of the local heat transfer coefficient on the impingement surface were determined for various Re and H/Dh. It was found the heat transfer coefficients generally tended to decrease with increasing separation distance and to increase with an increase in Reynolds number. This presented method is able to estimate the variation of the local Nusselt number with time. 相似文献
195.
The growth of sphere-like trimanganese tetraoxide (Mn3O4) nanoparticles on silk fiber was achieved by sequential dipping in an alternating bath of potassium hydroxide and manganese(II) nitrate under ultrasound irradiation. Some parameters such as the effect of pH, numerous sequential dipping and ultrasonic irradiation on growth of the nanoparticles have been studied. The samples were characterized with powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and wavelength dispersive X-ray (WDX). 相似文献
196.
Ali Rahmatpour Babak Kaffashi Somayeh Maghami 《Journal of Macromolecular Science: Physics》2013,52(9):1834-1846
Waterborne polyurethane (WBPU) was synthesized by a polyaddition reaction with toluene diisocyanate (TDI), polytetramethylene ether glycol (PTMEG), dimethylol propionic acid (DMPA), and triethylamine (TEA). Aqueous polyurethane dispersions with three different weight fractions, 30, 40, and 50 wt%, were prepared. All the dispersions made with these concentrations showed Newtonian viscosity behavior. Multiwalled carbon nanotubes (CNTs) were functionalized using a mixture of sulfuric and nitric acid at a ratio of 3:1 and added to these dispersions in two different loads of 0.1 and 0.5 wt%. Ultraviolet visible spectrometry (UV/Vis) spectroscopy proved the formation of stable suspensions following ultrasonic agitation. The rheology of these suspensions was characterized using dynamic and steady-state measurements. The higher amount of CNT in the suspension imparted non-Newtonian and complex viscoelastic behavior. This was attributed to a physical network formed due to the presence of the functionalized CNTs. The Cox-Merz rule was not observed for these suspensions. 相似文献
197.
Farshad Sohbatzadeh Abasalt Hosseinzadeh Colagar Saeed Mirzanejhad Somayeh Mahmodi 《Applied biochemistry and biotechnology》2010,160(7):1978-1984
We developed and employed a new geometrical structure of dielectric barrier discharge in atmospheric pressure for bacterial
broad spectrum sterilization. We utilized a plasma source having an AC power supply at 50 HZ and 5,400 V (rms value). We prepared
suspensions of the Gram-negative bacteria species (Escherichia coli, Pseudomonas aeruginosa) and a Gram-positive of Bacillus cereus with Luria–Bertani broth media up to OD600 nm = 0.25 of McFarland standard. Afterglow of non-thermal atmospheric pressure plasma treated these suspensions. The influence
of the atmospheric plasma afterglow on the species was assayed in different time durations 5, 10, and 15 min. The spectroscopic
results of this investigation indicated that the survival reduction of the species can reach to 100% for P. aeruginosa in an exposure time of 10 min, E. coli and B. cereus in an exposure time of 15 min. 相似文献
198.
Safar Irandoust-pakchin Hossein Kheiri Somayeh Abdi-mazraeh 《Computational Mathematics and Mathematical Physics》2013,53(7):920-932
In this paper, we introduce a modification of He’s variational iteration, homotopy analysis and optimal homotopy analysis methods for solving fractional boundary value problems. It is illustrated that the proposed methods are powerful fast numerical tools to find accurate solutions. It is illustrated that efficiency of these methods is based on proper choosing of initial guess. 相似文献
199.
Fazlollah Soleymani Mahdi Sharifi Bibi Somayeh Mousavi 《Journal of Optimization Theory and Applications》2012,153(1):225-236
In this paper, we first establish a new class of three-point methods based on the two-point optimal method of Ostrowski. Analysis
of convergence shows that any method of our class arrives at eighth order of convergence by using three evaluations of the
function and one evaluation of the first derivative per iteration. Thus, this order agrees with the conjecture of Kung and
Traub (J. ACM 643–651, 1974) for constructing multipoint optimal iterations without memory. We second present another optimal eighth-order class based
on the King’s fourth-order family and the first attained class. To support the underlying theory developed in this work, we
examine some methods of the proposed classes by comparison with some of the existing optimal eighth-order methods in literature.
Numerical experience suggests that the new classes would be valuable alternatives for solving nonlinear equations. 相似文献
200.