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971.
以拉把型腔模具为例,着重介绍了CimatronE软件在模具制造中的数控加工工艺规划、刀路合理选择和加工参数设置以及难加工部位的电极设计等关键技术,给出了模具型腔零件的完整制造过程。对现代模具合理设计和优化具有借鉴作用。 相似文献
972.
973.
974.
运用内聚力模型研究了锆-钛-钢复合板在粘结试验中的界面损伤过程,并利用扫描电子显微镜分析了界面断裂机理。运用正交试验研究了不同热处理工艺条件下的表面耐腐蚀性能,分析了保温温度、保温时间和升降温速率对粘结性能的影响。结果表明,I型裂纹加载下,界面损伤由内壁处开始,并逐渐发展至整个界面。界面整体属于脆性断裂,而波峰与波谷的过渡斜面则为混合断裂。腐蚀试验的塔菲尔极化曲线研究结果表明,锆覆层在HCl溶液中以点腐蚀为主,而在HAc溶液中以均匀腐蚀为主。爆炸焊接后,锆复合板的耐点腐蚀性能低于纯锆材料,并且保温温度越高,保温时间越长,耐腐蚀性能下降越明显。 相似文献
975.
This article addresses a production planning optimization problem of overall refinery. The authors formulated the optimization problem as mixed integer linear programming. The model considers the main factors for optimizing the production plan of overall refinery related to the use of run-modes of processing units. The aim of this planning is to decide which run-mode to use in each processing unit in each period of a given horizon, to satisfy the demand, such as the total cost of production and inventory is minimized. The resulting model can be regarded as a generalized lot-sizing problem where a run-mode can produce and consume more than one product. The resulting optimization problem is large-sized and NP-hard. The authors have proposed a column generation-based algorithm called branch-and-price (BP) for solving the interested optimization problem. The model and implementation of the algorithm are described in detail in this article. The computational results verify the effectiveness of the proposed model and the solution method. 相似文献
976.
污水处理过程的多目标多模型预测控制方法研究 总被引:1,自引:0,他引:1
针对污水处理过程节能降耗问题以及污水处理过程的高度非线性、强耦合、不确定性等特点.以基于活性污泥2号模型ASM2的A2/O污水处理过程为研究对象,提出了污水处理过程的多目标多模型预测控制方法.该方法首先采用聚类-PLS方法建立污水过程的多模型预测模型,然后构建了包含出水水质区间控制和经济性能指标的多目标优化结构的预测控制策略.仿真结果表明,与设定值预测控制方法相比,多目标优化预测控制策略在保证出水水质的前提下,能有效地节约能耗费用. 相似文献
977.
通过回顾上海化学工业区十余年的开发建设,阐述了"一体化"集成开发的规划理念及在开发建设过程中规划优化的原则和重要性,强调规划是提升化工区竞争力的重要抓手. 相似文献
978.
Ilkka Malinen 《Chemical engineering science》2008,63(13):3419-3430
The aim of this paper is to introduce modifications that enhance the usability of the bounded homotopy methods proposed by Paloschi [1995. Bounded homotopies to solve systems of algebraic nonlinear equations. Computers and Chemical Engineering 19, 1243-1254; 1997. Bounded homotopies to solve systems of sparse algebraic nonlinear equations. Computers and Chemical Engineering 21, 531-541], especially in the area of chemical engineering. In modified bounded homotopies, the homotopy path is tracked by exploiting mapped variables instead of unmapped ones. Path tracking based on mapped variables makes it significantly easier to track the bounded homotopy path even though the bounding zone has to be narrow. Mapping also improves the bounding effect of bounded homotopies and makes it possible to avoid unreasonable variable values in homotopy path tracking. The performance of the modifications is illustrated with test cases. These examples clearly show that the modifications enlarge the capability and accuracy of bounded homotopies when solving both small- and large-scale sets of nonlinear equations describing chemical engineering problems. 相似文献
979.
Phosphate rock with proper management could be a sustainable source of phosphorus for increased cowpea production on the Entisols of Sokoto Semi-arid zone. Therefore, field experiments were conducted in 2004 and 2005 rainy seasons to determine the influence
of Sokoto phosphate rock (SPR) and placement methods on the yield of cowpea varieties. Treatments consisted of factorial combination
of two varieties (Ba’adare and IAR48), three levels of SPR (25, 50 and 75 kg SPR ha−1) along with a control (0 kg SPR ha−1) and three placement methods (plough sole, broadcast and side-band) laid out in a randomized complete block design replicated
3 times. Results of phosphate rock and placement methods are presented in this paper. The study indicated significant (P < 0.01) response to applied SPR compared to control (1074 kg grain ha−1) in most parameters studied. Application of 25 kg SPR ha−1 significantly (P < 0.05) influenced higher pod yield and number of pods plant−1 only in 2004 trial. But, shelling percentage, grain yield, stover yield, 1000-grain weight, harvest index (HI) and number
of seeds pods−1 were not influenced by SPR levels. Significantly (P < 0.05) higher pod yield in 2004, grain yield, 1000-grain weight and number of pods per plant in 2004 and 2005, HI, shelling
percentage and number of seeds pod−1 in 2005, were observed in plough-sole than broadcast and band-side methods of fertilizer placement. Therefore, from this
study, it was concluded that SPR could be directly used as a source of P to sustain cowpea production (1527 kg grain ha−1 with 25 kg SPR compared to 1074 kg ha−1with 0 kg SPR). Application of 25 kg SPR ha−1 (3.74 kg P ha−1) using plough-sole method of fertilizer placement was most efficient under Sokoto semi-arid condition. 相似文献
980.