The UNIFAC-NRF group contribution activity coefficient model is used for the calculation of vapor–liquid equilibria of binary systems of the heavy alkanes and light gases such as CH4, C2H6, CO2 and N2. The linear combination mixing rule, LCVM, of the Huron–Vidal and Michelsen, Chen et al. modification of PSRK and Universal Group Contribution Equation of State of Ahlers and Gmehling are combined with the UNIFAC-NRF group activity coefficient model to correlation of the vapor–liquid equilibrium of both light and heavy hydrocarbons. The results show that the LCVM mixing rule combing with UNIFAC-NRF group contribution model correlate the asymmetric systems better than the LCVM-UNIFAC and the other EOS/GE models. Also the group contribution model is used for the prediction of the phase envelope of the synthetic fluid with accurate results. 相似文献
Inspired by the adhesive proteins of mussels, polydopamine (pDA) has emerged as one of the most widely employed materials for surface functionalization. Despite numerous attempts at characterization, little consensus has emerged regarding whether pDA is a covalent polymer or a noncovalent aggregate of low molecular weight species. Here, we employed single‐molecule force spectroscopy (SMFS) to characterize pDA films. Retraction of a pDA‐coated cantilever from an oxide surface shows the characteristic features of a polymer with contour lengths of up to 200 nm. pDA polymers are generally weakly bound to the surface through much of their contour length, with occasional “sticky” points. Our findings represent the first direct evidence for the polymeric nature of pDA and provide a foundation upon which to better understand and tailor its physicochemical properties. 相似文献
From a thermal point of view, zeotropic mixtures are likely to be more efficient than azeotropic fluids in low-temperature power cycles for reduction in exergy destruction occurring during heat absorption/rejection processes due to their suitable boiling characteristics. In this study, comprehensive energetic and exergetic analyses are mathematically performed for an organic Rankine cycle (ORC) system employing a potential binary zeotropic working fluid, namely R717/water. For this purpose, initially mass, energy, and exergy balance equations are derived. With regard to the similarity in molar mass of R717 (17.03 g mol?1) and water (18.01 g mol?1), there is no need to alter the size of the ORC components such as turbine and pump. In order to achieve the optimal thermal and exergy efficiencies of the ORC system, modified version a powerful and relatively new optimization algorithm called artificial bee colony (ABC) is used taking into account different effective constraints. The main motivation behind using ABC lies on its robustness, reliability, and convergence rate speed in dealing with complicated constrained multi-objective problems. Convergence rates of the algorithm for optimal calculation of the efficiencies are presented. Subsequently, due to the importance of exergy concept in ORC systems, exergy destructions occurring in the components are computed. Finally, the impacts of pressure, temperature, mass fraction, and mass flow rate on the ORC thermal and exergy efficiencies are discussed.
Individual laser-cooled atoms are delivered on demand from a single atom magneto-optic trap to a high-finesse optical cavity using an atom conveyor. Strong coupling of the atom with the cavity field allows simultaneous cooling and detection of individual atoms for time scales exceeding 15 s. The single atom scatter rate is studied as a function of probe-cavity detuning and probe Rabi frequency, and the experimental results are in qualitative agreement with theoretical predictions. We demonstrate the ability to manipulate the position of a single atom relative to the cavity mode with excellent control and reproducibility. 相似文献
Research on Chemical Intermediates - The compound ortho-chlorobenzylidene malononitrile (OCM) is the defining component of tear gas commonly referred to as CS gas. In present work, at first, OCM... 相似文献
A new operator called RESET “Reducing nuclEar Spin multiplicitiEs to singuleTs” is presented to acquire broadband proton decoupled proton spectra in one and two dimensions. Basically, the homonuclear decoupling is achieved through the application of bilinear rotation pulses and delays. A [BIRD]r,x pulse building block is used to selectively invert all proton magnetization remotely attached to 13C isotopes, which is equivalent to a scalar J decoupling of the protons directly attached to 13C from all other protons in the spin system. In conjunction with an appropriate data processing technique pure shift proton spectra are obtained. For this purpose, the concept of constant time acquisition in the observe dimension is exploited. Both ideas were merged together producing superior HSQC based pseudo 3D pulse sequences. The resulting HSQC spectra show cross peaks with collapsed multiplet structures and singlet responses for the proton chemical shift frequencies. An unambiguous assignment of signals from overcrowded spectra becomes much easier. Finally, the recently introduced SHARC technique is exploited to enhance the capability of the scalar J decoupling method. A significant reduction of the total measurement time is achieved. The time is saved by reducing the number of 13C chemical shift evolution increments and working with superimposed narrow spectral bandwidths in the 13C indirect domain. 相似文献
In Section 2 of the present paper, we introduce the concept of pseudocomplementation for semirings and show the semiring version of some known results in lattice theory. We also introduce semirings with pc-functions and prove some interesting results for minimal prime ideals of such semirings. In Section 3, some classical results for minimal prime ideals in ring theory are generalized in the context of semiring theory. 相似文献