长键槽在加工过程中的误差分析

简述了普通刨床加工长键槽产生加工误差的多种因素,并对加工过程中产生的主要误差、定位误差、对称度误差和刀具误差进行了综合分析。     

面向对象的制造资源分类与生产规划调度模型研究

在分析制造资源信息构成的基础上，应用面向对象（0－O）的技术，研究制造资源的结构形式及其相互关系，建立了面向对象的制造资源结构模型，为建立制造资源类库乃至工艺知识和工艺数据库奠定了良好的基础，并对制造资源与生产规划调度（PPS）的关系模型进行了研究。     

中压配电网的衍生接线模式

小区负荷发展在时间上是一个S形状,经历三个阶段:早期、中期和饱和期。本文研究了随小区负荷S形发展,接线模式的变化规律,提出中压配网衍生接线的思想。该思想利用较高负载率的接线模式,用时变的观点规划配电网络,选择接线模式;并针对架空线网和电缆网分别作了研究,指出架空线网的衍生经历了放射状网、“手拉手”网、多馈线联络到n-1网的过程;电缆网的衍生经历了“手拉手”网、双∏型网到多分段多联络网络的过程。衍生出的高负载率的接线模式与配电网自动化配合,具有推迟新建项目的潜在经济效益,优化了整个中压配电网络,并在对比了经济效益的基础上对杭州市规划新建小区提出了应用建议。     

关于旧城改造规划若干问题的综述

旧城改造方式有很多种,不论采取哪种方式,在旧城改造都要强调综合规划、综合改造和综合效益。旧城改造规划应遵循从实际出发,因地制 宜,量力而行,尽力而为的原则。其中应尤为注意几个关键问题,如旧城改造的重点;旧城改造的效益;旧城改造的速度和标准;旧城改造中新旧关系处理,保护和改造问题等等。为使旧城改造能够按规划的要求顺利进行,还需要实行灵活政策,综合开发。     

焊管生产中带钢的板边加工

焊接钢管生产中带钢边缘加工质量的好坏 ,直接影响焊管的成型、焊接的质量和生产效率。就目前带钢板边加工的各种方法和特点进行了论述 ,并就设备的国产化 ,提出自己的一些看法     

断阶滑行艇气层减阻试验研究

本文研究了2种重心位置、2种断阶方式、5种喷气流量对断阶滑行艇气层减阻的影响，取得了总阻力减少25％的效果。阻力减少的主要原因在于喷气时形成的空穴所引起的浸湿面积的减少。     

控制性详细规划的控制功能探析

解析控制性详细规划控制功能的概念、内涵与属性，研究影响控制功能发挥的因素并探讨减少影响的途径。     

广州市若干历史文化保护区保护规划

本文回顾了广州市内几个历史文化保护区规划在编制和实施。探讨历史文化保护区规划的新任务,从规划管理的角度,提出了切实可行的建议。     

Uncovering secrets behind low-resistance planing craft hull forms through optimization

There has always been significant interest within the naval architectural research community to identify ship hull forms with low resistance. While numerous design optimization frameworks have been proposed over the years to support the activity, very little attention has been paid towards the process of gaining an understanding of ‘what makes a good ship design superior?’. Furthermore, there have been limited attempts to identify computationally cheap indicators that can be used to distinguish between good and poor designs. A recent technique named discovery of innovative design principles, which is aimed at understanding the relationship between the design variables, is incorporated in this work. In this article, optimal high-speed planing craft hull forms with minimum calm-water resistance are identified through the use of three state-of-the-art optimization algorithms. Collections of such designs are then used to uncover insights into the underlying relationships between the variables. The importance of such relationships is further analysed to identify computationally cheap performance indicators that can be used in lieu of detailed calm-water resistance calculations. Such indicators are useful at the concept and preliminary design stages, where one needs to sieve efficiently through a number of candidate designs to identify the better ones for further analysis.     

Identification of acceleration deceleration profile of feed drive systems in CNC machines

In process planning, trajectory planning has generally disregarded the limitations of the feed drive systems in terms of acceleration, jerk, and motion blending. It results in poor prediction of the feed rate mainly in the transient phases and affects, consequently, the machining integrity and safety. Therefore, identifying and integrating the feed drive system limitations with the trajectory planning of the tool path are crucial in order to achieve the desired feed rate at the appropriate tool position. In this paper, a methodology based on time series modeling is proposed to identify the acceleration/deceleration (Acc/Dec) profile of a feed drive system. This profile provides the relationship between the actual feed rate, assumed proportional to the tachometer signal, and the commanded feed rate specified in the G-Code file. A particular shape of the input has been addressed to allow the application of the time series modeling. The different characteristics of this input are carefully considered to avoid both nonlinear response due to saturation and excitation of the high frequency components of the feed drive. The resulting model is transformed into a Finite Impulse Response (FIR) filter and applied as an (Acc/Dec) processor to determine the actual feed rate from the commanded feed rate. The good agreement between the model output and the experimental results demonstrates the effectiveness of the proposed identification method. It is demonstrated that integrating these limitations with the trajectory planing results in a feasible trajectory.