High-accuracy turning with slender boring bars

The paper presents the theoretical background for new approaches for achieving high accuracy in finish turning with slender tools.The approaches are developed especially for high-accuracy turning with vibrationsdamped boring bars with a length-to-diameter ratio up to14.The approaches are based on established force models of turning operations and utilize a three-pass scheme where the deflection of the boring bar is calculated and compensated for in the final passes.Very good results are achieved in practical machining tests for a great variation of cutting conditions.Experiments show that the typical diameter error is 0.01 mm,even in situation where the tool deflection is 0.3 mm.     

常温下桃保鲜的研究

<正>对于桃的保鲜,目前一般采用低温贮藏。国际标准化组织也推荐低温气调贮藏。据报导一般低温气调贮藏可使桃的保鲜期延长数月。但是,鉴于我国目前的经济技术状况,大力发展此项技术并不适宜。其一、产地修建冷库需要大的投资;其二、冷库操作时的水电消耗较     

基于虚拟仪器的自动化测试系统设计与软件实现

基于虚拟仪器技术,依据实际的某接收机测试设备研制任务,设计了一套自动化测试系统。系统以工控机为核心,数据采集卡、GPIB控制器、串行接口板卡等为扩展,Lab-VIEW编程语言为工具。通过测控软件实现对多种接口和多路通道的控制,并对实时数据进行处理分析,完成测试功能。系统扩展性好,自动化程度高,改进了以往手动对硬件进行设置和测试的测试方法,节约了成本,操作界面友好,在某型号导弹测试中得到应用。     

Engineering geological investigations for a subsea tunnel for an oil pipeline across the hjeltefjorden strait

A subsea tunnel across the approx. 6-km-wide and 375-m-deep Hjeltefjorden strait was planned to be part of STATOIL's concept for transportation of crude oil to the Mongstad refinery (GULLPIPE). The planning and engineering geological investigations were carried out in three phases from May 1983 to May 1984. This article deals with the different engineering geological investigations made, the results obtained, the evaluation and the recommendations made in connection with this subsea tunnel. Of particular importance were refraction seismic investigations of the seabed at depths of more than 350 m. Also, core drilling at such depths was carried out for the first time.     

Spectral Approximation of Partial Differential Equations in Highly Distorted Domains

In this paper we discuss spectral approximations of the Poisson equation in deformed quadrilateral domains. High order polynomial approximations are used for both the solution and the representation of the geometry. Following an isoparametric approach, the four edges of the computational domain are first parametrized using high order polynomial interpolation. Transfinite interpolation is then used to construct the mapping from the square reference domain to the physical domain. Through a series of numerical examples we show the importance of representing the boundary of the domain in a careful way; the choice of interpolation points along the edges of the physical domain may significantly effect the overall discretization error. One way to ensure good interpolation points along an edge is based on the following criteria: (i)?the points should be on the exact curve; (ii)?the derivative of the exact curve and the interpolant should coincide at the internal points along the edge. Following this approach, we demonstrate that the discretization error for the Poisson problem may decay exponentially fast even when the boundary has low regularity.     

Investigating an “Internet of Hybrid Products”: Assembling Products, Interactions, Services, and Networks through Design

This article takes up the relations between products, people, and the Internet. Our investigation is set in the context of the emergence of networked and service-driven physical products. The article builds upon the curation and design of an exhibition that pulls together recent hybrids composed of physical objects as well as digital things and networked services. Through investigating this selection of both prototypical and widely available consumer products, we seek to understand how the previously-separate domains of product, interaction, and service design might be combined in order to design and research new hybrid products, services, and interactions. Taken together, these investigations point toward an “Internet of Hybrid Products” that draws heavily from social practices in networked media that is already highly branded and in urgent need of attention from design research.