Plasma power can make better powders

It may be a truism to say that round powders pack better, but spheroidisation of powder particles is one of the successful commercial applications of induction plasma technology and can play a key role in substantial improvement of powder quality and fluidity…     

论薄板坯连铸连轧产品质量优势

通过对薄板坯连铸连轧工艺的分析，深入研究了其产品的质量优势，同时还指出了在产品生产过程中需要重点注意解决的一些问题。     

Parametric circles and spheres

Formulations for parametric circles and spheres in terms of rational Gaussian (RaG) curves and surfaces are introduced. With the proposed formulations, a full circle is generated by interpolating a closed RaG curve to the vertices of an equilateral triangle, and a full sphere is generated by interpolating a closed RaG surface to the vertices of an octahedron with equilateral triangular faces. Generation of circles and spheres in this manner is very intuitive and easy to remember as the weights are all 1 and the nodes are all unique and uniformly spaced.     

硫含量对钴钼型耐硫脱氧剂的脱氧活性影响

研究了工艺气中硫含量对钴钼型耐硫脱氧剂脱氧活性的影响。通过常压微反 -色谱装置测定脱氧剂的本征脱氧活性 ,加压原粒度反应器测定脱氧剂的表观脱氧活性 ,结合实际经验确定了耐硫脱氧剂所需的最低硫含量。还讨论了温度、压力、空速对耐硫脱氧剂脱氧活性的影响。结果表明 ,耐硫脱氧剂完全能满足耐硫变换工艺的要求 ,而且有耐硫变换的作用 ,并对耐硫变换催化剂起到保护作用     

生烃化学动力学在川东北普光气田的应用

普光气田是四川盆地近期发现的规模最大、埋藏最深、资源丰度最高的气田。通过认识普光气田各个烃源岩层的贡献量、生烃关键期与构造演化的关系、油气成藏具体模式等，建立生烃化学动力学模型、标定参数，结合地区烃源岩参数和地史、热史资料，定量描述该地区的生烃过程及油裂解成气过程。认为：普光地区的主力烃源岩为下志留统泥岩；主要干酪根生油期为早二叠世末到早三叠世末期（距今286Ma至240Ma）；主要干酪根生气期为中三叠世（距今240Ma至230Ma）；主要气源是原油后期热裂解气，原油裂解成气的时间比较晚，主要油裂解成气期为早白垩世（距今144Ma至97．5Ma），从而决定了普光气田的成藏模式为“多期成藏，油气转化，晚期定位”。图2表3参33     

Stability analysis of network-based cooperative resource allocation strategies

Resource allocation involves deciding how to divide a resource of limited availability among multiple demands in a way that optimizes current objectives. In this brief paper we focus on one type of distributed resource allocation problem where via an imperfect communication network multiple processors can share the load presented by multiple task types. We introduce asynchronous “cooperative” resource allocation strategies, and show that they lead to a bounded cumulative demand.     

Nonpathological Lyapunov functions and discontinuous Carathéodory systems

Differential equations with discontinuous right-hand side and solutions intended in Carathéodory sense are considered. For these equations, sufficient conditions which guarantee both Lyapunov stability and asymptotic stability in terms of nonsmooth Lyapunov functions are given. An invariance principle is also proven.     

Finding feasible mold parting directions using graphics hardware

We present new programmable graphics hardware accelerated algorithms to test the 2-moldability of geometric parts and assist with part redesign. These algorithms efficiently identify and graphically display undercuts as well as minimum and insufficient draft angles. Their running times grow only linearly with respect to the number of facets in the solid model, making them efficient subroutines for our algorithms that test whether a tessellated CAD model can be manufactured in a two-part mold. We have developed and implemented two such algorithms to choose candidate directions to test for 2-moldability using accessibility analysis and Gauss maps. The efficiency of these algorithms lies in the fact that they identify groups of candidate directions such that if any one direction in the group is undercut-free, all are, or if any one is not undercut-free, none are. We examine trade-offs between the algorithms' speed, accuracy, and whether they guarantee that an undercut-free direction will be found for a part if one exists.