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61.
通过具体工程实例,探讨在大型石油化工企业(炼油厂)油品储运系统中,如何经济合理地确定中间原料油罐罐容,使之既能满足生产要求,又节省投资,提出中间原料油罐罐容设置的比较经济合理的方法。 相似文献
62.
The effects of protein concentration, ionic strength, and lyophilization on heat-induced aggregation of soy proteins were analyzed by SDS-PAGE, SEC-HPLC and laser light scattering (LLS). SDS-PAGE profile suggested that the aggregates were formed via non-covalent forces and/or disulfide bonds. At ionic strength of zero, SEC-HPLC revealed that the samples were composed of three major fractions: aggregates, intermediate fractions and non-aggregated molecules. Furthermore, the relative proportion of the aggregate fraction increased as protein concentration increased. Similarly, LLS indicated that the average hydrodynamic radius (Rh) increased at higher protein concentration. In sample with an ionic strength of zero, the intermediate fraction decreased after freeze-drying with a concomitant increase of the aggregate fraction. When the sample was heated at elevated ionic strength, the SEC-HPLC and LLS profiles changed substantially, the intermediate fractions decreased, and lyophilization had effect on the fraction of aggregates. These experiments suggest novel strategies for producing soy protein aggregates with controlled properties. 相似文献
63.
ZHOUWen－Jie HEZe－Jun 《核技术(英文版)》2001,12(3):165-168
The production of dileptons from the chemically equilibrating quark gluon plasma in the intermediate mass region has been studied.Comparing with the calcuated results based on the thermodynamic equilibrium system of quark gluon plasma,it has been found that the quark phase of the chemically equilibrating system gives rise to an even larger enhancement of the dileptons production.Therefore.such an enhancement of dilepton production may signal the formation of quark gluon plasma. 相似文献
64.
《Ceramics International》2023,49(12):20290-20297
In this work, the Sm0.2Ce0.8O1.9 (SDC) buffer layer was used to replace the Gd0.1Ce0.9O1.95 (GDC) buffer layer to improve the long-term stability and performance of the solid oxide fuel cells (SOFCs) in the intermediate temperature (550–750 °C). The buffer layer was prepared by screen printing method. The micromorphology of the SDC buffer layer and the cell structures was observed by scanning electron microscopy (SEM). The electrochemical impedance spectroscopy (EIS) results showed that the polarization resistance (RP) of the cell with SDC buffer layer was smaller than that of the cell with GDC buffer layer, reducing the RP values by 43.52% and 43.33%, respectively (SDC-cell: 0.12 Ω cm2 at 650 °C and 0.27 Ω cm2 at 600 °C). The maximum power density of the cell with SDC buffer layer is 560 mW cm−2 at 650 °C, which was 25% higher than that with GDC buffer layer. The long-term durability of the cell with SDC buffer layer was better than that of the cell with GDC buffer layer. These provide an excellent prospect for utilizing SDC buffer layer. 相似文献
65.
《Advanced Powder Technology》2022,33(3):103507
This study investigates the effect of intermediate stress ratio (b) on the mechanical behaviour of granular soil in true triaxial tests. A CFD-DEM solver with the ability to model compressible fluid and moving mesh has been developed and calibrated based on existing experimental test results on Nevada sand. The effect of b on the undrained true triaxial test, which has been neglected in the literature, was investigated using a reasonable number of models. The effects of the initial confining stress and initial void ratio also have been studied. The developed model was used to calculate the hydrodynamic forces on the particles and evaluate the ratio of the particle–fluid interaction force to the resultant force on the particles. It has been demonstrated that, in numerical studies, the effect of these forces cannot be neglected. 相似文献
66.
《International Journal of Hydrogen Energy》2022,47(21):11402-11416
This work addresses the use of TiO2-based particles as an intermediate layer for reaching fully dense Pd-membranes by Electroless Pore-Plating for long-time hydrogen separation. Two different intermediate layers formed by raw and Pd-doped TiO2 particles were considered. The estimated Pd-thickness of the composite membrane was reduced in half when the ceramic particles were doped with Pd nuclei before their incorporation onto the porous support by vacuum-assisted dip-coating. The real thickness of the top Pd-film was even lower (around 3 μm), as evidenced by the cross-section SEM images. However, a certain amount of palladium penetrates in some points of the porous structure of the support up to 50 μm in depth. In this manner, despite saving a noticeable amount of palladium during the membrane fabrication, lower H2-permeance was found while permeating pure hydrogen from the inner to the outer surface of the membrane at 400 °C (3.55·10?4 against 4.59·10?4 mol m?2 s?1 Pa?0.5). Certain concentration-polarization was found in the case of feeding binary H2–N2 mixtures for all the conditions, especially in the case of reaching the porous support before the Pd-film during the permeation process. Similarly, the effect of using sweep gas is more significant when applied on the side where the Pd-film is placed. Besides, both membranes showed good mechanical stability for around 200 h, obtaining a complete H2/N2 ideal separation factor for the entire set of experiments. At this point, this value decreased up to around 400 for the membrane prepared with raw TiO2 particles as intermediate layer (TiO2/Pd). At the same time, complete selectivity was maintained up to 1000 h in case of using doped TiO2 particles (Pd–TiO2/Pd). However, a specific decrease in the H2-permeate flux was found while operating at 450 °C due to a possible alloy between palladium and titanium that is not formed at a lower temperature (400 °C). Therefore, Pd–TiO2/Pd membranes prepared by Electroless Pore-Plating could be very attractive to be used under stable operation in either independent separators or membrane reactors in which moderate temperatures are required. 相似文献
67.
《International Journal of Hydrogen Energy》2022,47(63):27187-27198
Very-high-temperature gas-cooled reactors (VHTRs) are promising for efficient, zero-carbon hydrogen production. The intermediate heat exchanger (IHX) is a key piece of equipment for VHTR-coupled hydrogen production. Constrained by the limited space within the VHTR, the IHX must be efficient and compact. Besides, radioactive graphite dust deposition will reduce the performance and reliability of IHXs. Therefore, understanding the thermal-hydraulic and dust-deposition characteristics of IHX tube bundles is crucial for the design and safe operation of IHXs. This study uses the unsteady k-kl-ω model to simulate flow and heat transfer in IHX tube bundles. The discrete particle model combined with a deposition model is used to predict the movement and deposition behavior of graphite dust. The deposition model is achieved using user-defined functions. The model and code are first validated by empirical correlations and experimental results. The transient flow fields show that, in the in-line arrangement, unsteady and asymmetric periodic flow occurs with a period of about 0.047 s. The flow is steadier and more symmetric in the staggered arrangement due to the restriction of the main flow to the separation vortices. The maximum circumferential heat-transfer coefficient for inner tubes occurs at the impact point, where the central angle θ is about 60° and 0° for the in-line and staggered arrangement, respectively. The graphite-dust deposition rate decreases with increasing Reynolds number and particle size and the deposition mechanism is also analyzed in detail. With the current design conditions, the Nusselt number of the staggered arrangement increases by 27.90%–29.17% compared with the in-line arrangement, and the deposition rate decreases by 1.52%–3.15%. Furthermore, new correlations for Nusselt number and friction factor are developed for the thermal-hydraulic design of IHX tube bundles. 相似文献
68.
Ion implantation followed by pulsed laser melting is an extensively-studied method for hyperdoping Si with impurity concentrations that exceed the equilibrium solubility limit by orders of magnitude. In the last decade, hyperdoped Si has attracted renewed interest for its potential as an intermediate band material. In this review, we first examine the important experimental results on both solid and liquid phase crystal regrowth from early laser annealing studies. The highly non-equilibrium regrowth kinetics following pulsed laser melting and its implications for dopant incorporation processes are discussed. We then review recent work in hyperdoped Si for enhanced sub-band gap photoresponse and give a brief discussion on photodetector device performance. 相似文献
69.
《Ceramics International》2020,46(15):23314-23325
A composite cathode exhibits low activation polarisation by spreading its electrochemically active area within its volume. Composite cathodes enable the development of high-performance electrodes for solid oxide fuel cells (SOFCs) at intermediate temperatures (600 °C – 800 °C) because of their significant role in determining the kinetics of oxygen reduction reaction (ORR). Few anions O2− are transferred through the electrolyte component when the ORR is low, thereby lowering the reaction with cation H+ from an anode side to transfer electrons along the outer circuit to the cathode side to participate in ORR. The resistance to the ORR at the cathode is minimised, thereby contributing to performance degradation and efficiency loss in existing SOFCs, especially at intermediate temperatures. The suitability and compatibility of the cathode and electrolyte are crucial in the development of cathodes and electrochemical reactions. The intercomponent compatibility is important to ensure the robustness and durability of SOFCs, especially at an operating temperature around 800 °C, at which the components experience extreme thermal and mechanical stresses. Composite cathodes are used to improve cathode performance. These composite cathodes help enhance the properties of mixed electronic–ionic conductors and the intercomponent compatibility. Herein, we reviewed historical data of composite-cathode development for SOFCs, including its basic principle and criteria. The overall performance of as-synthesised composite cathodes in terms of microstructure, electrochemical reaction and intercomponent compatibility is briefly discussed. 相似文献
70.