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排序方式: 共有148条查询结果,搜索用时 254 毫秒
21.
Luis M. Romeo Luis I. DíezIsabel Guedea Irene BoleaCarlos Lupiáñez Ana GonzálezJavier Pallarés Enrique Teruel 《Experimental Thermal and Fluid Science》2011,35(3):477-484
Oxyfuel combustion is a promising alternative for CO2 capture. While this has been proven in pulverized fuel (PF) burners, research in fluidized bed (FB) reactors is still scarce. Our work aims to increase the knowledge about this technology. To this purpose, a 95 kWth FB oxyfuel combustion test rig has been erected. Its main characteristics are described in this paper, giving detailed information on the subsystems: the FB reactor, the fuel and oxidant supplies, and ancillaries. Plant flexibility is emphasized. It allows to operate under different CO2/O2 ratios, and to recycle CO2 from the flue gases. Both the processes design and monitoring are supported by simulations that have been validated against experimental data, regarding fluid dynamics, combustion, and heat transfer. Finally, the performance of the facility has been tested both with coal alone and blended with biomass. CO2 concentrations over 90% (dry basis) in the flue gases have been obtained. Comparison of air and oxygen combustion tests and operational recommendations are discussed, confirming the feasibility of the FB oxyfuel technology for CO2 capture purposes. 相似文献
22.
Summary The polymer beds described are synthesized in aqueous solution directly in the column or batchwise in the form of large clusters of small particles. The conventional, expensive step involving prepreparation of beads in an organic solvent is thus omitted. Beds were synthesized from piperazine diacrylamide, methacrylamide and allyl glycidyl ether. The epoxy-activated beds thus obtained were used for covalent attachment of either nonpolar ligands (e.g. octadecanol) or polar OH-rich substances (e.g. dextran). The non-polar beds were used for reversed-phase chromatography, as were polar ones following coupling with 1,2-epoxyoctadecane. Coating with OH-rich substances serves two purposes: (I) the matrix becomes hydrophilic, decreasing nonspecific interactions (modifiers can be excluded) and hence increases resolution and (II) many—OH groups are available (e.g. for coupling to epoxides), a prerequisite for high ligand density. Resolution of proteins was high even at high flow rates. Depending on the method used for the synthesis of the bed, resolution of proteins either increased with an increase in flow rate or decreased slinghtly. Choice of the correct temperature was very important for high resolution of CNRr-digested peptides. 相似文献
23.
电磁波的非线性动力理论 总被引:1,自引:1,他引:0
使用全动力途径,严格地推导了左旋圆极化电磁波的非线性色散关系。所得到的色散关系被用来分析电子Bernstein波和高杂波所激发的电磁辐射。结果表明:(1)电子Bernstein波可以激发频率上移辐射,也可以激发频率下移辐射,这取决于背景等离子体频率wpe与电子回旋频率Ωe的比值大小;(2)高杂波只能激发频率下移辐射;(3)当电子Bernstein波位于高杂共振层时,频率上移辐射和频率下移辐射可以同 相似文献
24.
K. I. Sakodynskii S. A. Volkov K. F. Khalilov V. I. Reznikov V. Yu. Zel'venskii 《Chromatographia》1985,20(9):538-542
Summary Chromatography is carried out under the conditions of fluidization, in long, straight tubes under organized and non-organized
conditions. Under non-organized conditions the column is filled only with a sorbent. In organized conditions, either metal
coils are added into the column or a segmented column is utilized with metal grids. The results obtained are compared to those
obtained under fixed-bed conditions when the column is completely filled with the sorbent. Organized fluidized beds provide
a significant decrease in longitudinal bandspreading. 相似文献
25.
Plasmas in modern tokamak experiments contain a significant fraction of impurity ion species in addition to main deuterium background. A new unlike-particle collision operator for δf particle simulation has been developed to self-consistently study the non-local effects of impurities on neoclassical transport in toroidal plasmas. A new algorithm for simulation of cross-collisions between different ion species includes test-particle and conserving field-particle operators. The field-particle operator is designed to enforce conservation of number, momentum and energy. It was shown that the new operator correctly simulates the thermal equilibration of different plasma components. It was verified that the ambipolar radial electric field reaches steady state when the total radial guiding center particle current vanishes. 相似文献
26.
A. H.?KhaterEmail author D. K.?Callebaut M. A.?Helal A. R.?Seadawy 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,39(2):237-245
The nonlinear evolution
of the kink instability of a plasma
with an elliptic magnetic stagnation line is studied by means
of an amplitude expansion of the ideal magnetohydrodynamic equations.
Wahlberg et al. [12] have shown that, near marginal stability,
the nonlinear evolution of the stability can be described in terms
of a two-dimensional potential U(X,Y), where X and Y represent
the amplitudes of the perturbations with positive and negative
helical polarization. The potential U(X,Y) is found to be nonlinearly
stabilizing for all values of the polarization. In our paper a Lagrangian
and an invariant variational principle for two coupled nonlinear ordinal
differential equations describing the nonlinear evolution of the stagnation
line instability with arbitrary polarization are given. Using a trial function
in a rectangular box we find the functional integral. The general case for
the two box potential can be obtained on the basis of a different ansatz
where we approximate the Jost function by polynomials of order n instead
of a piecewise linear function. An example for the second order is
given to illustrate the general case. Some considerations concerning
solar filaments and filament bands (circular or straight) are
indicated as possible applications besides laboratory experiments
with cusp geometry corresponding to quadripolar cusp geometries for
some clouds and thunderstorms. 相似文献
27.
S. Mahmood N. Akhtar 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,49(2):217-222
Linear and nonlinear ion acoustic waves in the presence of adiabatically heated ions in magnetized electron-positron-ion plasmas
are studied. The Sagdeev potential approach is employed to obtain the energy integral equation in such a mulitcomponent plasma
using fluid theory. It is found that electron density humps are formed in the subsonic region in magnetized electron-positron-ion
plasmas. The amplitude of electron density hump is decreased with the increase of hot ion temperature in electron-positron-ion
plasmas. However, the increase in positron concentration and obliqueness of the wave increases the amplitude of nonlinear
structure. The increase in positron concentration also reduces the width of the nonlinear structure in a magnetized multicomponent
plasma. The numerical solutions in the form of solitary pulses are also presented for different plasma cases. The results
may be applicable to astrophysical plasma situations, where magnetized electron-positron-ion plasma with hot ions can exist. 相似文献
28.
D. D. Pawar S. W. Bhaware A. G. Deshmukh 《International Journal of Theoretical Physics》2008,47(3):599-605
In this paper we have investigated bulk viscous fluid plane symmetric dust magnetized string cosmological model. To get a
deterministic model, it is assumed that ε=λ, and a relation between metric potential B=RA
n
. The behaviour of the model in the presence and absence of magnetic field together with physical and geometrical aspects
of the model are also discussed. 相似文献
29.
复杂气固两相系统的微观结构 总被引:2,自引:0,他引:2
流化床中的气固两相流动是一个高度复杂的非线性混沌系统。本文利用激光粒子动态分析仪(PDA)得到的循环流化床中颗粒脉动速度信号,采用FFT分析了脉动信号的宽频谱特征,在此基础上应用小波法分析了脉动信号的动态特征,得到了颗粒脉动速度的微观结构,指出颗粒脉动速度的非线性特性是流化床具有混沌特性的根源,且在不同的尺度上颗粒脉动速度表现出各向异性的特征。 相似文献
30.