Experimental Simulation of the Reactor Section of Fluid Cokers: Comparison of FCC and Fluid Coke Particles

The hydrodynamics of fluid cokers were studied in a pressurized fully cylindrical cold model of diameter 483 mm, geometrically and dynamically scaled down by a factor of ～20 from commercial units. Differential pressure fluctuations, voidage distributions, solids momentum flux distributions and steady state gas mixing behaviour in the reactor section are compared for the same operating conditions with two kinds of particles, FCC and fluid coke. The voidage distributions and core‐annular flow structures in the reactor section were similar enough that either FCC or fluid coke particles can be used for cold modelling of fluid cokers.     

相位噪声建标方案和不确定度分析

相位噪声是频率测量的重要项目,其表征能直观地观察到连续的相位调制边带及离散寄生信号分量等。介绍了实验室时间频率计量相位噪声建标的方案,并对其系统的不确定度进行了分析。     

BOPP塑瓶大输液瓶胚冷却方式的改进

介绍了BOPP塑瓶制瓶工艺的间歇冷却和在线冷却2种冷却方式,并分析了其优缺点,在此基础上进行了改造。实践证明改造后的在线冷却方式技术成熟、工艺简单、改造时间短、费用低,提高了产品质量及吹瓶合格率,大大降低了生产成本,节约了劳动力。     

Wear Characteristics of Diamond Tools in Machining Ceramics

Wear characteristics of natural diamonds used to machine ceramic materials at a depth of cut of 2 μm and a speed of 1600 m/min were investigated. The diamond tools used for the machining tests were inspected using the Laue back reflection technique and scanning electron microscopy (SEM). Wear characteristics of the diamond tools appeared to be influenced by the material properties of the ceramics being machined, the build-up on the tips of the diamond tools, and the crystallographic orientations of the diamond crystals. Three wear patterns were identified: single-flat wear, double-flat wear, and micro-chipping wear. The single-flat and double-flat wear patterns were primarily observed in machining silicon nitride and alumina; the microchipping wear pattern was observed in machining silicon carbide. The wear rate for the microchipping pattern was found to be one to two orders of magnitude higher than those for other wear patterns. Silicon nitride wore the diamond tools faster than alumina did; however, it often formed built-up lips which reduced the wear of the diamond tools.     

模糊离散事件系统的自适应监督控制

针对基于模糊自动机的模糊离散事件系统模型在实际工程应用中的不足,从产生式规则出发,建立了该类系统的模糊规则化模型.通过定义结构化的模糊因子并以其构成模糊规则,实现了对模糊状态转移函数的描述.提出了一种包含模糊监控器和模糊控制器的系统闭环监控结构,并针对模糊推理环节给出了具体的实现方法.通过定义一种可动态调整的模糊规则允许发生度,实现了系统的自适应监控机制.借助电动汽车电池均衡管理系统对方法进行了验证.结果表明,系统的运行过程符合预定的目标.     

EXPERIMENTAL AND NUMERICAL STUDY ON GAS FLOW IN THE GRID ZONE OF JETTING-FLUIDIZED BEDS

A grid model describing the gas flow and interchange in the grid zone of jetting fluidized beds is proposed. Based on this model, longitudinal gas concentration profiles in the jet and annulus are calculated. The longitudinal gas concentration distribution is also experimentally investigated in a jetting fluidized bed with an inside diameter of 50 mm at the ambient temperature, and a jetting fluidized bed with an inside diameter of 80 mm at high temperatures. Comparison between the calculated and experimental results has shown that the experimental profiles can be qualitatively predicted by the grid model. The results indicated that the concentration in the grid zone depends on the gas exchange between the jet and the annulus, and the net gas flow from the jet to the annulus. The gas exchange rate is mainly affected by the inlet gas velocity from the nozzle. The present study is thought to be helpful to understand the grid gas behavior in the jetting fluidized bed coal gasifier.     

蔬果磷稳定性研究

用非离子型表面活性剂和吡咯类化合物作稳定剂，加入由约含８０％蔬果磷原药配制的２５％乳油中，制剂被装入安瓿瓶内，在５４℃条件下，储存１４天。分析蔬果磷的含量，没有加稳定剂的，蔬果磷仅残留约５３．４４％，加入稳定剂的，蔬果磷含量至少存在９６．２９％。然而当蔬果磷２５％乳油用３５％左右的原药和稳定剂配制时，在上述储存条件下蔬果磷的分解率为４５％－７０％。     

房建工程工具式定型组合木模板施工技术

相比于散支散拆木模板,定性组合木模板具有脱模容易、拼装方便、节约用材、可回收利用等诸多优势,在大力推广绿色建筑背景下得到了广泛应用.在房建工程中使用工具式定型组合木模板时,既要做好前期模板设计与物料准备,同时还要加强外墙、内墙、楼板等部分模板安装的技术管理,为混凝土浇筑与成型提供必要的支持.首先概述了定型组合木模板的应用优势,结合某工程实例,分别从前期施工准备、中期模板安装、后期模板拆卸等方面,简要概述了施工技术要点,为房建工程推广应用这一技术提供经验参考.     

正六边形孔蜂窝组合梁腹板纯弯屈曲研究

蜂窝构件具有承载力高、抗弯刚度大和方便穿越管线等优点,近年来广泛应用于各类高层建筑和大跨度结构中.对于蜂窝构件来说,腹板的局部屈曲是其主要破坏模式之一,屈曲会导致腹板局部变形的急速增加,直至退出工作,并可能导致构件整体失稳及结构上的连锁反应.在传统钢结构设计中通过对腹板高厚比进行限制来避免腹板局部屈曲的发生,而蜂窝构件...     

绿色建筑与绿色施工现状及展望

随着我国社会经济与科学技术的快速发展,各行各业都取得了很大的进步,建筑业的发展尤为显著。作为支持我国经济发展的重要行业之一,同时也是实现我国经济社会可持续发展的重点领域。近年来,我国积极贯彻可持续发展原则,倡导绿色建筑。基于此,本文对绿色建筑与绿色施工的关系、绿色施工推进建议进行了研究。