2000m3低温丙烯球罐球壳板型式和材料的选择

大型球罐球壳板型式和材料的选择是设计的首要环节,从这两方面论述了设计时选择的过程。     

聚丙烯球形高效催化剂的工业应用研究

介绍了DQ-2型球形高效催化剂在间歇式液相本体法聚丙烯生产装置上进行工业应用的试验研究，试验证明，该催化剂具有节水、节电、反应平稳且操作时间短等聚合反应特性，催化剂活性平均为42kgPP／(gCat)，一级品率达90％，并与非球型高效催化剂进行了比较。     

Preparation and application of polybenzoxazine adsorption resin

The synthesis and application of polybenzoxazine adsorption resin was studied. First, the precursor was synthesized by the solventless method. And then a kind of spherical and granular polybenzoxazine resin was obtained using reverse‐phase suspension polymerization technique in the process of solidification. Besides, the influence of dispersion medium, the volume ratio of precursor to medium, the solidification temperature, and the agitation speed were studied in detail in the process of polymerization. Second, the spherical shape of the polybenzoxazine resin was identified by scanning electronic microscope and the thermal stability of resin was measured by thermogravimetric analysis. Finally, the adsorption capacity of the spherical resin on pyridine was studied in cyclohexane systems. The correlation coefficient of Langmuir adsorption constant temperature line was bigger than 0.99, which indicated that the equilibrium sorption date was coincident with the Langmuir isotherm equation. And the saturated adsorptive capacity of dried resin achieved 222.2 mg g^?1. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Coding scheme based on spherical polar coordinate for control over packet erasure channel

Like feedback strategy, coding scheme is an important part of networked control system design as well. On the basis of spherical polar coordinate, a novel coding scheme is proposed for stabilization problem of discrete linear time invariant system subject to packet erasure channel with feedback. The coding scheme uses encoder without access to control inputs. In the case that a decoder does not use control inputs, a definite relation between the quantized data and the corresponding quantization error is established, which helps to analyze the stability of system, and a selective quantization method is adopted, by which finite data rate is obtained. In the case that a decoder uses control inputs, instead of quantizing the system state at each time step as usual, the encoder quantizes the initial state all the time by updating quantizer. Sufficient conditions guaranteeing the system stable are presented for two cases, respectively, and the corresponding design methods for coding schemes are given. Copyright © 2012 John Wiley & Sons, Ltd.     

Static solution on four-region spherial cavity expansion model in a pressure sensitive medium

Spherical cavity expansion model is often used to study the mechanic characteristics of pressure sensitive mediums. The most important one we do in the paper is that we construct a four-region model with σθ≠0 in damage region,which is different from what Satapathy did before and is more reasonable. By adopting this model,different constitutive equations were constructed by different method-elastic mechanics in elastic region,damage mechanics and fracture mechanics in damage region,and macro-micro mechanics theory in plastic region. Then using Durban's self-similarity assumption,the control differential equations with boundary conditions were established,and the static numerical solution of stress field and displacement field in the three different regions of elastic,damage and plastic area were discussed respectively. Results showed that this four-region model can describe precisely the mechanic characteristics of pressure sensitive mediums under initial pressure.     

压力敏感性材料球形孔洞动态扩展问题

为进一步研究岩土材料爆炸场的特点,采用椭圆型屈服准则和自相似假设,并结合Hopkins三区模型,研究幂硬化材料球形孔洞动态扩展问题.通过对弹性区的研究得出弹性区应力的分布和弹塑性交界处的连续条件;然后在塑性区给出一个求解动态扩展问题的非线性微分方程组;最后通过打靶法数值求解该非线性微分方程组,给出满足边界条件的数值解,并讨论材料参数对场量的影响.结果表明,椭圆型屈服准则能很好地描述压力敏感性材料中孔洞的动态扩展.     

Mathematical models of grinding manufacture and tooth contact analysis of spherical gears

The spherical gear is a gear-driven mechanism with two degrees of freedom (DOF), which can transfer spatial motion and power. Grinding machining of the spherical gear is performed with a plate grinding wheel by using generating method, and based on mathematical model of the plate grinding wheel, the mathematical model of the spherical gear is set up. And then, the meshing model of a spherical gear pair is developed and the tooth contact analysis (TCA) of the spherical gear pairs is performed. After that, th...     

煤尘爆炸特征参数影响因素研究

采用20L球形爆炸装置研究了煤尘粒径、浓度、点火能量对煤尘爆炸最大压力、爆炸最大压力上升速率的影响。研究结果表明,在煤尘粒径一定的条件下,随着煤尘浓度的增大,爆炸最大压力及爆炸最大压力上升速率先增大后减小,煤尘浓度在400~480g/m3之间取得爆炸最大压力最大值0.94MPa、爆炸最大压力上升速率最大值28.79MPa/s;在煤尘浓度一定的条件下,爆炸最大压力不随煤尘粒径的减小而单调变化,爆炸最大压力上升速率随煤尘粒径的减小而逐渐增大;随着点火能量的增大,爆炸最大压力及爆炸最大压力上升速率明显增加。     

我国回转窑水泥不同粉磨工艺颗粒形貌剖析

利用电子显微镜及专用的计算机软件等方法，对我国目前大中型水泥企业不同粉磨工艺下水泥颗粒形貌状况进行了研究分析。研究结果表明，我国不同粉磨工艺下水泥颗粒形貌存在较大差别，提高磨机研磨功能有利于改善水泥颗粒形貌。