Size segregation in gas-solid fluidized beds with continuous size distributions

Discrete-particle simulations of a gas-solid fluidized bed are used to investigate the species segregation (de-mixing) behavior of systems with continuous particle size distributions. Both Gaussian and lognormal distributions are investigated over a range of distribution widths, restitution and friction coefficients, and gas velocities. The results indicate that: (i) the average particle diameter decreases as the height within the bed increases, (ii) the level of segregation increases with an increase in the width of the particle size distribution, and (iii) segregation is attenuated as bubbling becomes more vigorous. Furthermore, the shape of the local size distribution (i.e., Gaussian or lognormal) is found to mimic that of the overall size distribution in most regions of the fluidized bed.     

Texaco与Shell煤气化工艺比较分析

煤气化技术对于促进煤炭的综合利用、改善当前资源紧缺状况,并减少环境污染具有重要的意义。阐述了Texaco和Shell煤气化的工艺流程,并对2种煤气化工艺进行了比较分析,找出各自的优缺点,为煤气化工艺的选择提供参考。     

基于动态MANCOVA的混合制程虚拟测量算法

在晶圆/液晶面板等批次加工过程中,产品质量的及时估计与品质管制是提高产能和降低成本的有效途径.针对"少量多样"的混合制程,利用逐步回归算法挑选该制程的关毽变量,引入产品的效益因子,建立混合制程的虚拟测量模型;为克服系统扰动对模型精度的影响,以产品效益因子为状态量建立该制程的状态方程,利用Kalman滤波器递归估计模型参数得到动态的MANCOVA模型;最后通过某湿式蚀刻制程的工程应用验证了该算法的有效性.     

秦安县农村户用改进型沼气池建造的关键技术

近年来,随着我县农村户用沼气建设力度的不断加大,为缓解我县能源资源短缺的现状,通过对农村户用沼气池施工技术及工艺的改进,进行技术集成示范,总结出秦安农村户用改进型沼气池的建造技术,为该地区沼气事业的发展提供科学依据.     

连续式双膜分离塔的数学模型

本文建立了适用于连续式双膜分离塔的数学模型。用实验数据验证了数学模型的可行性和合理性。将本模型与已发表的模型进行了比较,结果表明本模型具有形式简单、计算方便和适用范围更宽广等优点。     

湿法腈纶生产的含腈废水处理实验研究

采用不同方法对湿法腈纶废水进行预处理，比较了它们的处理效果和特点。研究中使用的菌种预处理方法达到了理想的效果，废水中大分子有机污染物被迅速、高效地分解为挥发性脂肪酸和氨氮等，为后续的接触氧化以及反硝化创造了良好的条件，COD和TKN的总去除率分别为92％和85％，最终出水达到或优于行业二级排放标准。     

国内干法脱硫剂工业应用现状

介绍了国内主要的干法脱硫过程以及脱硫剂的工业应用情况和发展趋势 ,比较了现有国内不同脱硫剂的使用情况、主要性能、适用条件和经济技术指标等 ,认为选择合适的脱硫剂应考虑其各自特点及影响因素     

国外ABS生产技术进展

综述了世界ＡＢＳ树脂的生产及供求，介绍了各种生产工艺的进展，对其技术特点及产品性能进行了比较。     

ESTIMATION FOR NONNEGATIVE AUTOREGRESSIVE PROCESSES WITH AN UNKNOWN LOCATION PARAMETER

Abstract. Consider an AR(1) process given by X ^t=γ+ø X _t+ Z _t≥ 1. where 0 ≤γ, 0 ≤ø 1 are unknown parameters and the innovations Z _t, ≥ 1, are independently and identically distributed positive random variables. We propose estimates of (γø) which are obtained as the solution to a linear programming problem and establish their strong consistency. When the Z _ts have the exponential distribution. our estimate becomes the conditional maximum likelihood estimate given X ₀. Under the assumption of regular variation of the innovation distribution at its left and right endpoints (assumed to be 0 and ∝ respectively), we establish asymptotic limit laws for the estimates. Consistent estimators for a class of moving-average processes with heavy-tailed innovation distribution are also presented.