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841.
分析和归纳了现有曲面数控加工中的全局刀具干涉(碰撞)检验算法,提出了一种新的在刀位轨迹生成过程中检测和避免全局刀具干涉的方法,该方法先依据斜立方体凸包法粗检现行的刀具方向与斜立方体凸包之间是否存在干涉,若不存在,则该刀具方向是可行的;若存在,则需通过进一步的详细检测法来判断该空间自由曲面与现行的刀具方向之间是否真正存在全局刀具干涉.该方法能有效地避免全局刀具干涉,提高无干涉刀位轨迹的生成速度. 相似文献
842.
根据FMS生产计划、工件加工工艺以及FMS资源等情况提出了一个零件分批模型和分批优化算法.根据零件加工时间、系统托盘数及零件批量等对所加工任务进行分批预处理,在交货期等约束条件下以各机床的加工时间分配均衡为目标,采用逐次搜索剩余零件空间的方法找出最合适的零件分批组合.仿真结果表明算法是有效的. 相似文献
843.
采用大孔吸附树脂分别对以水和乙醇为溶剂制得的板栗壳棕色素Ⅰ和色素Ⅱ进行精制,确定了色素Ⅰ以D4020,色素Ⅱ以NKA-9为吸附剂,并对精制效果作了评价。本文为吸附树脂在色素中的应用提供一定的科学依据。 相似文献
844.
Investigation of the kinetic mechanism of the demanganization reaction between carbon-saturated liquid iron and CaF2-CaO-SiO2-based slags 下载免费PDF全文
Sheng-chao Duan Chuang Li Han-jie Guo Jing Guo Shao-wei Han Wen-sheng Yang 《矿物冶金与材料学报》2018,25(4):399-404
The demanganization reaction kinetics of carbon-saturated liquid iron with an eight-component slag consisting of CaO-SiO2-MgO-FeO-MnO-Al2O3-TiO2-CaF2 was investigated at 1553, 1623, and 1673 K in this study. The rate-controlling step (RCS) for the demanganization reaction with regard to the hot metal pretreatment conditions was studied via kinetics analysis based on the fundamental equation of heterogeneous reaction kinetics. From the temperature dependence of the mass transfer coefficient of a transition-metal oxide (MnO), the apparent activation energy of the demanganization reaction was estimated to be 189.46 kJ·mol-1 in the current study, which indicated that the mass transfer of MnO in the molten slag controlled the overall rate of the demanganization reaction. The calculated apparent activation energy was slightly lower than the values reported in the literature for mass transfer in a slag phase. This difference was attributed to an increase in the "specific reaction interface" (SRI) value, either as a result of turbulence at the reaction interface or a decrease of the absolute amount of slag phase during sampling, and to the addition of calcium fluoride to the slag. 相似文献
845.
Reductive recovery of manganese from low-grade manganese dioxide ore using toxic nitrocellulose acid wastewater as reductant 下载免费PDF全文
The hydrometallurgical strategy of extracting Mn from low-grade Mn ores has attracted attention for the production of electrolytic manganese metal (EMM). In this work, the reductive dissolution of low-grade MnO2 ores using toxic nitrocellulose acidic wastewater (NAW) as a reductant was investigated for the first time. Under the optimized conditions of an MnO2 ore dosage of 100 g·L-1, an ore particle size of -200 mesh, concentrated H2SO4-to-NAW volume ratio of 0.12, reaction temperature of 90℃, stirring speed at 160 r·min-1, and a contact time of 120 min, the reductive leaching efficiency of Mn and the total organic carbon (TOC) removal efficiency of NAW reached 97.4% and 98.5%, respectively. The residual TOC of 31.6 mg·L-1 did not adversely affect the preparation of EMM. The current process offers a feasible route for the concurrent realization of the reductive leaching of Mn and the treatment of toxic wastewater via a simple one-step process. 相似文献
846.
正确有效的评价方法和反馈方法对于方案设计专家系统的质量是至关重要的。本文提出了评价子系统的基本模式,研究了评价数学模型和优化反馈模型,研制了建立评价子系统的工具软件E&F,并对该软件进行了应用试验。 相似文献
847.
针对当前物流行业中存在的信息泄露问题,提出了一种面向物流行业的用户隐私信息保护方法。该方法基于匿名通信的思想,对现有的物流条码技术加以改进,使得物流过程中的每个站点只能获取到部分用户信息,从而有效地避免了用户隐私信息的泄露。本方法采用6位验证码作为取货码来验证取件人身份,并且该取货码在签收完成之前只有收件人知道,从而有效地防止了快递冒领等问题的出现。理论分析和模拟测试结果表明,该方法在保证物流转运效率的同时,降低了用户信息泄露的概率,有效地保护了用户的个人隐私。 相似文献
848.
A graph theory model of the human nature structure ( GMH ) for machine vision and image/graphics processing is described in this paper.Independent from the motion and deformation of con-tours, the human nature structure (HNS) embodies the most basic movement characteristics of the body.The human body can be divided into basic units like head, torso, and limbs.Using these basic units, a graph theory model for the HNS can be constructed.GMH provides a basic model for human posture processing, and the outline in the perspective projection plane is the body contour of an image.In addition, the GMH can be applied to articulated motion and deformable objects, e.g., in the design and analysis of body posture, by modifying mapping parameters of the GMH. 相似文献
849.
随着科学、信息技术的进步,政策积极引导以及市场需求的不断增加,低空无人机航摄系统突破了众多技术瓶颈,整个行业都得到了快速发展,满足了众多领域的实际应用需要。现针对弹射式低空无人机航摄系统的发展现状、特点、实施过程以及存在的若干问题进行探讨,以此来指导低空无人机航摄实践,更好地满足我国经济社会迅猛发展的航摄测绘需求。 相似文献
850.
The success of embryo implantation is a critical step towards further embryo development and pregnancy outcome. The observations and investigations on embryo implantation have been over a century. A huge body of knowledge has been accumulated in anatomy, histology, ultrastructure and hormonal regulation; as well as recently in depth information about molecular signaling pathways got from studies of genomic wide gene screening and specific gene deletion. The knowledge from basic research has also substantially helped to initiate and improve the Artificial Reproductive Technology (ART) in clinical applications. Now we've known that the normal embryo implantation involves the embryo's development into an implantation-competent blastocyst and the synchronized transformation of uteri into a receptive stage. The interdependent relationship between the blastocyst and uterus involves complicated hormonal regulation and local paracrine, juxtacrine interactions. In this paper, we review some important historical findings regarding uterine receptivity and blastocyst activation, as well as some less discussed topics such as embryo spacing, embryo orientation. Further understandings on detailed mechanisms during the process of embryo implantation will help cure women infertility as well as develop new generation of non-steroids contraceptives. 相似文献