TBP／煤油热解焚烧装置设备材料的腐蚀

针对ＴＢＰ／煤油热解焚烧系统的一些可能环境，选取了不锈钢１Ｃｒ１８Ｎｉ９Ｔｉ和Ａ３碳钢等几种材料，在不同的料液组成，温度，试验时间等综合条件下研究了它们在料液中的腐蚀情况。在高温且有热解蒸汽的真实环境下研究了不锈钢１Ｃｒ１８Ｎｉ９Ｔｉ等几种材料的高温腐蚀状况。结果表明：不锈钢１Ｃｒ１８Ｎｉ９Ｔｉ在料液和热解气氛中皆呈均匀腐蚀，在料液中，其腐蚀速率随料液含水量和温度的增加而增大；在高温热解蒸汽中，其     

Estimating the width of a uniform distribution when data are measured with additive normal errors with known variance

The problem of estimating the width of the symmetric uniform distribution on the line when data are measured with normal additive error is considered. The main purpose is to discuss the efficiency of the maximum likelihood estimator and the moment method estimator. It is shown that the model is regular and that the maximum likelihood estimator is more efficient than the moment method estimator. A sufficient condition is also given for the existence of both estimators.     

基于网格服务的数据库统一查询系统的设计与实现

首先介绍了数据网格研究现状和科学数据网格的项目背景,分析了科学数据网格环境下数据资源共享和统一查询的需求,然后设计了基于网格服务的科学数据库统一查询系统模型,并着重阐述了该系统模型中各个模块的详细设计内容,最后总结和评估了该系统。该系统现已经成功地应用于科学数据网格。     

Spray forming: Science and technology

Spray forming involves sequential gas atomization of a melt into a spray of fine droplets and their deposition on a substrate to build up a high-density preform. The rapid solidification inherent in spray deposition generates refined, equiaxed and low segregation microstructures. A number of promising features of this near-net shape manufacturing process are highlighted and compared, wherever possible, with the conventional casting and PM techniques. Some commercial nozzles used to create spray and mechanisms associated with spray generation are described. The consolidation of the droplets and the development of the microstructure in the deposit are primarily governed by the nature of the spray and the thermal state of droplets on the deposition surface. Several microstructural characteristics of the deposit are presented and their origin in spray deposition is discussed.     

Reduction of droplet of tantalum oxide using double slit in pulsed laser deposition

We developed a double slit method in order to reduce droplets that were a problem in pulsed laser deposition (PLD) of tantalum oxide. The tantalum oxide films were deposited using KrF excimer laser ablation of a Ta target in 5 mass% O₃ at a pressure of 10 Pa. Stoichiometric and dense films with few droplets were obtained at a pressure of 10 Pa. Without double slit, as the laser pulses increased, the number of droplets containing rich metal on the film gets increased and its size became larger, and the surface morphology of the target also became more and more rugged. It was found that the number of droplet could be controlled by changing the initial roughness of the target. The number of droplets with a diameter size of under 1 μm was decreased to 1/10 of their sizes. Droplets larger than 3 μm, which mostly affect the corrosion resistance and hardly increase even beyond the laser pulses of 100 000. It is evident from this study that the double slit is a very effective method for reducing the droplets, which are otherwise a problem often seen in film production by PLD.     

A modified θ projection model for constant load creep curves-II. Application of creep life prediction

To minimize the deviation of the predicted creep curves obtained under constant load conditions by the original θ projection model, a new modified version that can be expressed by $\epsilon ={\theta }_1\left(1-e^{-{\theta }_{2}t}\right)+{\theta }_3\left(e^{{\theta }_4{e}^{{\theta }_5\epsilon }t}-1\right)$, was derived and experimentally validated in our last study. In the present study, the predictive capability of the modified θ projection model was investigated by comparing the simulated and experimentally determined creep curves of K465 and DZ125 superalloys over a range of temperatures and stresses. Furthermore, the linear relationship between creep temperature and initial stress was extended to the 5-parameter model. The results indicated that the modified model could be used as a creep life prediction method, as it described the creep curve shape and resulted in predictions that fall within a specified error interval. Meanwhile, this modified model provides a more accurate way of describing creep curves under constant load conditions. The limitations and future direction of the modified model were also discussed. In addition, this modified θ projection model shows great potential for the evaluation and assessment of the service safety of structural materials used in components governed by creep deformation.     

驱油剂对中间层原油乳状液稳定性的影响

考察了孤岛油田中间层原油和外输原油的稳定性差异以及驱油剂对原油乳状液稳定性的影响.对于同一种破乳剂TA1031,在相同的脱水条件下,外输原油与中间层原油的最终脱水率分别为95.48％和78.40％,加入二元复合驱之后,脱水率分别为83.33％和70.30％.随着驱油剂浓度的增加,zeta电位的负值越来越大,乳状液稳定性...     

Minimizing total weighted completion time when scheduling orders in a flexible environment with uniform machines

We consider the scheduling of orders in an environment with m uniform machines in parallel. Each order requests certain amounts of k different product types. Each product type can be produced by any one of the m machines. No setup is required if a machine switches over from one product type to another. Different product types intended for the same order can be produced at the same time (concurrently) on different machines. Each order is released at time zero and has a positive weight. Preemptions are allowed. The completion time of an order is the finish time of the product type that is completed last for that order. The objective is to minimize the total weighted completion time. We propose heuristics for the non-preemptive as well as the preemptive case and obtain worst case bounds that are a function of the number of machines as well as the differences in the speeds of the machines. Even though the worst-case bounds we showed for the two heuristics are not very tight, our experimental results show that they yield solutions that are very close to optimal.     

Validation of Solids Suspension Viscosity Measurements Using Computational Fluid Dynamics

Accurately measuring the viscosity of a solids suspension requires uniform suspension of the solids in the viscometer cup. In a cup‐and‐impeller viscometer system, solids may settle when the impeller speed is too low, causing viscosity measurements to appear lower than that of a well‐suspended slurry. Pre‐mixing of a solids suspension is typically performed to achieve steady state prior to measurements. Data here shows that the measured viscosity values differ depending on the pre‐mixing speed, indicating that the solids are not properly suspended at all speeds. A commonly used cup‐and‐vane impeller system can be thought of as a mixing tank that should operate above the uniform‐suspension speed (USS), although determining the USS experimentally is rather subjective. Computational fluid dynamics (CFD) is employed here to determine the USS of a pretreated corn stover (PCS) solids suspension and to confirm the experimentally measured USS.     

一种产生矩形光斑的LED均匀照明系统设计

随着LED光源芯片性能的稳步提升,各种LED光源被应用于不同领域,从而根据需要产生不同形状的光斑。在本文中,笔者提出了一种能够产生均匀矩形光斑的设计方法。在这种设计方法中,光斑的形状取决于复眼结构、聚光杯以及准直透镜对光路的再分配,此外依据研究需要成功将其应用于一些实例。