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201.
研究了撫順頁岩油残油的高速裂化。在沸点高于200°的裂化产品参加循环的情况下,可得到49.1%的气体(包括C_4),4.7%的五碳餾分和37.8%的汽油餾分。气体产品中含有70%的烯烴,其中乙烯和丙烯各为26%。五碳餾分基本上由烯烴所組成,其中有約10%的2-甲基丁二烯-1,3,正戊烯-1約33%,2-甲基丁烯約13%。汽油餾分經酸碱洗滌后的性貭为:d_4~(20)0.7728,n_D~(20)1.4444,磺化98%,碘价184,含芳香烴和烯烴各約40%。以硅酸鋁催化精制后的汽油餾分可用作馬达燃料的组分,或經精餾而得到芳香烴。  相似文献   
202.
研究了以硅酸铝为载体的 MoS_2催化剂的表面物化性质,以及载体中 SiO_2/Al_2O_3含量比不同时这些物化性质的变化.实验结果表明,组成不同的各硅铝载体载硫化钼后,其表面孔隙结构均有不同程度的变化。这种变化部分是由于承载过程的条件引起的,而主要是由于硫化钼和载体的组成分相互作用而引起.这种相互作用也使载体的表面酸度改变,但这种改变和其裂化活性的变化不是一致的.这种相互作用使载体生成新的粗孔,同时,改变了载体的相组成——形成类似α—SiO_2的新相.根据组成不同的各种硅铝载体在载 MoS_2后所发生的各种表面物化性质的变化,认为硫化钼和硅铝载体各组成分(氧化铝、氧化硅、活性硅铝络合物)形成了新的化合物.  相似文献   
203.

The purpose of this investigation is to theoretically shed some light on the effect of the unsteady electroosmotic flow (EOF) of an incompressible fractional second-grade fluid with low-dense mixtures of two spherical nanoparticles, copper, and titanium. The flow of the hybrid nanofluid takes place through a vertical micro-channel. A fractional Cattaneo model with heat conduction is considered. For the DC-operated micropump, the Lorentz force is responsible for the pressure difference through the microchannel. The Debye-Hükel approximation is utilized to linearize the charge density. The semi-analytical solutions for the velocity and heat equations are obtained with the Laplace and finite Fourier sine transforms and their numerical inverses. In addition to the analytical procedures, a numerical algorithm based on the finite difference method is introduced for the given domain. A comparison between the two solutions is presented. The variations of the velocity heat transfer against the enhancements in the pertinent parameters are thoroughly investigated graphically. It is noticed that the fractional-order parameter provides a crucial memory effect on the fluid and temperature fields. The present work has theoretical implications for biofluid-based microfluidic transport systems.

  相似文献   
204.
利用人工合成的多晶材料研究了镍锗尖晶石在扩散域的高温蠕变性质。材料颗粒尺寸为0.5μm到8μm,压缩试件为圆柱状,使用气体介质围压试验机。常压蠕变试验过程中,围压为300MPa,温度为1123K到1523K,差应力在55-330MPa范围内。从实验结果得到的镍锗尖晶石在扩散域的流动律表明流动机制为颗粒边界的扩散蠕变(Coble蠕变)。将橄榄石和尖晶石的蠕变数据外推到地球内部条件,粗粒时尖晶石强度远大于橄榄石,粒度减小时,尖晶石比橄榄石还要弱。  相似文献   
205.
This paper investigates a treated fly ash to act as a synthetic zeolite to remediate soils polluted with heavy metals and metalloids (As, Pb, Cu, Zn, Fe, Cd and Mn). Four types of such 'zeolites' were synthesized by hydrothermal treatment of a calcareous fly ash derived from Greek lignite-fired power plants: two with excess of sodium hydroxide in a solid/liquid ratio of 50 g·L^-1, and two with excess of fly ash in a solid/liquid ratio of 100g·L^-1. Soil samples were obtained from a former mining site at Lavrion, Greece. Mobilization and transfer of metals to the retention agents was effected by using HCI aq 1M, with satisfactory results with respect to As, Pb, Cu, Mn and Cd. The great variety of metal complexes in soil was found to be of major importance for the effectiveness of the overall process. The final products were solidified either on their own, or by using additives such as lime and cement.  相似文献   
206.
207.
This paper investigates the exact and approximate spectrum assignment properties associated with realizable output-feedback pole-placement type controllers for single-input single-output linear time-invariant time-delay systems with commensurate point delays. The controller synthesis problem is discussed through the solvability of a set of coupled diophantine equations of polynomials. An extra complexity is incorporated to the above design to cancel extra unsuitable dynamics being generated when solving the above diophantine equations. Thus, the complete controller tracks any arbitrary prefixed (either finite or delaydependent) closed-loop spectrum. However, if the controller is simplified by deleting the above mentioned extra complexity, then the robust stability and approximated spectrum assignment are still achievable for a certain sufficiently small amount of delayed dynamics. Finally, the approximate spectrum assignment and robust stability problems are revisited under plant disturbances if the nominal controller is maintained. In the current approach, the finite spectrum assignment is only considered as a particular case to the designer‘s choice of a (delay-dependent) arbitrary spectrum assignment objective.  相似文献   
208.
Let p(z) be a polynomial of degree at most n. In this paper we obtain some new results about the dependence of p(Rz)-βp(rz) + α (R+1/r+1)n-|β | p(rz) s on p(z) s for every α, β∈ C with |α|≤ 1, |β | ≤ 1, R > r 1, and s > 0. Our results not only generalize some well known inequalities, but also are variety of interesting results deduced from them by a fairly uniform procedure.  相似文献   
209.
We demonstrate two distinct emerging terahertz (THz) biomedical imaging techniques.One is based on the use of a new single frequency THz quantum cascade laser and the other is based on broadband THz time domain spectrocopy.The first method is employed to derive a metastasis lung tissue imaging at 3.7 THz with clear contrast between cancerous and healthy areas.The second approach is used to study an osseous tissue under several imaging modalities and achieve full THz spectroscopic imaging based on the freque...  相似文献   
210.
以Nb/Cu复合管作为外包套材料,Nb棒作为中心增强体,通过原位法粉末装管工艺(in-situ PIT)制备了不同芯丝结构的TiC 粉末掺杂MgB2/NbCu多芯线材.在高纯流动氩气保护条件下、700℃烧结2h进行成相反应.对烧结后的线材分别进行了应力-应变分析、微观结构以及超导电性等分析检测.拉伸实验分析表明,Nb芯...  相似文献   
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