Research of Digital Manufacturing Technology Application on Ultra-precision Optical Workpiece Machining

Digital manufacturing technology can be used in optical field to solve many problems caused by traditional machining. According to the characters of digital manufacturing and the practical applications of ultra-precision machining,the process of digital ultra-precision machining and its technical contents were presented in this paper. In the conclusions,it was stated that the digitalization of ultra-precision machining will be an economical and efficient way for the production of new sorts of optical workpieces.

Active vibration control of spindle in ultra-precision turning machine

In order to minimize vibration and improve rotary precision of spindle, we apply active vibration control technique to ultra-precision turning machine based on the analysis of vibration characteristic of aerostatic bearing spindle. Using aerostatic bearing itself as actuator, the vibration of spindle is controlled by adjusting admission pressure respectively and by changing pressure distribution in the bearing. The experiments and simulations prove that this method can minimize the vibration of spindle effectively.

Tool path generation of ultra-precision diamond turning: A state-of-the-art review

With the increasing market demand for optical complex surface parts,the application of multi-axis ultraprecision single-point diamond turning is increasing.A tool path generation method is very important to decrease manufacturing time,enhance surface quality,and reduce cost.Compared with the tool path generation of the traditional multi-axis milling,that of the ultra-precision single-point diamond turning requires higher calculation accuracy and efficiency.This paper reviews the tool path generation of ultra-precision diamond turning,considering several key issues:cutter location(CL)points calculation,the topological form of tool path,interpolation mode,and G code optimization.

345 GHz Band-Pass Filter Using Ultra-Precision Machining Technology

This paper presents a terahertz（THz）band-pass filter using ultra-precision machining technology based on Chebyshev filter prototype.This iris inductive window coupled waveguide filter was designed by using 8 resonant cavities with a center frequency of 345 GHz and a 7% bandwidth.The final design fulfills the desired specifications and presents the minimum insertion loss of 1.55 d B and the return loss of less than 15 d B at 345 GHz.The stop-band rejection is50 d B off the center frequency about 30 GHz,which means it has a good performance of high stop-band suppression.Compared with the recent development of THz filters,this filter possesses the characteristic of simple structure and is easy to machining.

Analysis of opposing left-turn conflicts based on traffic conflict technology

The relationship between the opposing left-turn conflict and the traffic participants was analyzed in this study. Based on the traffic conflict technology, the image data were collected in a real traffic situation. The relationship was investigated under two different conditions. The number of opposing left-turn conflicts was positively correlated with the number of left-turn vehicles while the ratio of left-turn vehicles to opposing vehicles was less than 1, and showed a positive correlation with the number of opposing-through vehicles when the ratio of left-turn vehicles to opposing vehi- cles was more than 1. In other words, the opposing left-turn risk was positively correlated with the number of the minor traffic participants, which had a negative effect on the whole traffic system op- eration.

Development and Prospects of China's Space Technology——Will China's space technology be brilliant again at the turn of the century?

For China,at the turn of the century,how to keep the position of the space power,how to stimulate the enthusiasm of the space technicians and how to keep pace with the world space technology,all of these questions lie ahead of the Chinese people.So we may say China’s space industry now is in the key stage.If the space industry draws great attention from the central government and the people of the country,it will have a brilliant future in the 21st century.We should put our eyes on the 21st century and prepare to explore space resources.It is difficult for us to keep pace with the times if we do not explore space resources and try to earn "the money in space".

Research on Chinese Urban Modernity Issues From the Perspective of Technology Rational Critique

With the development of urbanization,metropolises and megapolises are emerging.Urbanization is being completed with the driving force of capital;meanwhile,technology has achieved the quest of capital.In this thesis,in light of Henri Lefebvre’s ideology of technology rational critique,Chinese urban modernity issues under the perspective of technology rational critique were analyzed,including issues like eroded urban texture,urban mechanization,and urban segregation.The technology rational root of Chinese urban modernity issues was discussed from the turn of technical artifacts from design intention to application intention.In the end,possible methods to solve these Chinese urban modernity issues were illustrated based on Henri Lefebvre’s urban development theory.

How Is Tech Criticism Possible?On the Significance of Digital Technology as a Paradigm of Literary Criticism

Technology is one of the basic dimensions of literary criticism,but it is often ignored for multiple reasons.As digital technology intervenes in literary production,literary criticism is being approached through the technological dimension.Technology-Based literary criticism now transcends linguistic centrism,using digital technology as a means and method of literary criticism,and bringing technology to the center stage of literary criticism.Technology-Based literary criticism,which features an intersection of interpretive and empirical perspectives,triggers multiple transmutations of the subjects of literary criticism,and also enriches the connotations of literary texts.Tech criticism came from,and has evolved with the changes of literary criticism in the productive forces and the relations of production,which are driven by digital technology.What digital technology has opened up for literary criticism is a comprehensive field,where literary criticism is in a transboundary dynamic of "relational production." Therefore,we need to develop a sense of relation and a sense of systems to better interpret present-day literary criticism.

Study on 6-DOF active vibration-isolation system of the ultra-precision turning lathe based on GA-BP-PID control for dynamic loads

The vibration disturbance from an external environment affects the machining accuracy of ultra-precision machining equipment.Most active vibration-isolation systems(AVIS)have been developed based on static loads.When a vibration-isolation load changes dynamically during ultra-precision turning lathe machining,the system parameters change,and the efficiency of the active vibration-isolation system based on the traditional control strategy deteriorates.To solve this problem,this paper proposes a vibration-isolation control strategy based on a genetic algorithm-back propagation neural network-PID control(GA-BP-PID),which can automatically adjust the control parameters according to the machining conditions.Vibration-isolation simulations and experiments based on passive vibration isolation,a PID algorithm,and the GA-BP-PID algorithm under dynamic load machining conditions were conducted.The experimental results demonstrated that the active vibration-isolation control strategy designed in this study could effectively attenuate vibration disturbances in the external environment under dynamic load conditions.This design is reasonable and feasible.

论科技伦理的四大转向

科技伦理需要实现四大转向,即伦理转向、生活转向、时代转向与中国转向,否则将有违科技伦理的宗旨和使命。伦理转向是针对科技伦理的去伦理化现象而言的,目的是确认伦理是科技活动的底色,伦理属性是科技伦理的根本属性;生活转向是针对科技伦理的理论化现象而言的,目的是回归伦理学的生活本体,并确认科技伦理的实践伦理属性;时代转向是针对科技伦理的架空式研究而言的,目的是确认科技伦理的时代主题以及其作为伦理学的当代形态的角色;中国转向是针对科技伦理的西方化倾向而言的,目的是促进中国科技伦理自主知识体系的建立。在四大转向中,伦理转向是前提,生活转向是基础,时代转向是关键,中国转向是落脚点。

Weakening of the anisotropy of surface roughness in ultra-precision turning of single-crystal silicon

Ultra-precision machining causes materials to undergo a greatly strained deformation process in a short period of time.The effect of shear strain rates on machining quality, in particular on surface anisotropy, is a topic deserving of research that has thus far been overlooked.This study analyzes the impact of the strain rate during the ultra-precision turning of single-crystal silicon on the anisotropy of surface roughness.Focusing on the establishment of cutting models considering the tool rake angle and the edge radius, this is the first research that takes into account the strain rate dislocation emission criteria in studying the effects of the edge radius, the cutting speed, and the cutting thickness on the plastic deformation of single-crystal silicon.The results of this study show that the uses of a smaller edge radius, faster cutting speeds, and a reduced cutting thickness can result in optimally uniform surface roughness, while the use of a very sharp cutting tool is essential when operating with smaller cutting thicknesses.A further finding is that insufficient plastic deformation is the major cause of increased surface roughness in the ultra-precision turning of brittle materials.On this basis, we propose that the capacity of single-crystal silicon to emit dislocations be improved as much as possible before brittle fracture occurs, thereby promoting plastic deformation and minimizing the anisotropy of surface roughness in the machined workpiece.

The course of science and technology,and acoustics:past,present and future——turning to information acoustics

In this paper, the historical development of acoustics has been briefly reviewed. It can be concluded that acoustics study has been developed along with the same atream of the historical developments of science and technology, the category of acoustics has changed from the nature-oriented and passive physical acoustics to the human-oriented and active information acoustics. It has been extended over a variety of wide fields.

信息化部门在高校数字化转型环境下面临的新挑战

在教育数字化转型的大背景下,各高校积极开展数字化转型的研究与实践。关于高校数字化转型“转什么”和“如何转”的问题,已有大量文献进行了深入探讨。然而,具体到执行层面,“谁来转?哪个部门能够有效执行转型规划?”等问题仍需进一步被明确。许多高校将这一职责赋予了信息化职能部门,但传统的信息化部门在权责职能上与数字化转型的要求存在较大差距。文章首先梳理了高校网络与信息化工作的组织架构,阐述了各类架构的主要优点,并分析了高校传统信息化部门的主要职责及其在数字化转型中的权责差距。高校数字化转型应推动“六转”先行,即从决策层的理念、信息化部门的管理架构、管理机制与体制、权责划分、各类人员素养提升以及转型经费的统筹6个方面率先转型,才能为高校数字化转型的成功提供重要保障。

基于双峰谐振长周期光纤光栅的海水盐度传感器

为研制高灵敏海水盐度传感器,本文基于CO_(2)激光技术成功制备出一种工作在色散转折点(DTP)附近的长周期光纤光栅(LPFG)。首先,利用CO_(2)激光器在80μm细单模光纤上制备出工作在DTP附近的LPFG,证明了采用CO_(2)激光微加工技术制备较短周期LPFG的可能性。其次,通过调控CO_(2)激光器的制备周期,使高阶包层模式LP_(1,9)工作在DTP附近,从而显著提高了LPFG的折射率灵敏度。在双峰谐振增敏效应的作用下,当海水盐度从5.001‰变化到39.996‰时,光栅周期为115.4μm的双峰谐振LPFG平均灵敏度高达0.279 nm/‰。研究结果表明,本文制备的LPFG海水盐度传感器具有谐振损耗大和灵敏度高的优点,其在海水盐度监测领域具有较好的应用前景。

迈向技术型自治:数字乡村中村民自治空间转向的失序及调适

有序是数字乡村中村民自治空间转向的价值追求,在实践中却出现了与之相抵牾的失序现象,这既不利于营造清朗的虚拟社区空间,也不利于形成良好的网络政治生态。在数字乡村中村民自治空间转向失序的现实表征为:村庄外部人员假冒身份进入虚拟社区开展活动,村庄内部人员在虚拟社区中随意处理私人事务、发布传播不当言论以及违背在线议事规则等。失序现象的形成蕴藏着“科层制治理失灵”“市场治理失灵”“自组织治理失灵”等三重逻辑,其中,政府缺位导致刚性制度对村民自治空间转向的规制有限,市场利益驱动导致虚拟社区成为售卖商品和诈骗活动的平台,村委会的治理局限导致村庄制度约束力不足和技术可选择空间小。依靠元治理调适村民自治空间转向失序现象,应突出强调政府在村民自治空间转向中的作用,通过制度供给及柔性治理等方式明确村民自治虚拟社区平台的政治属性,规范虚拟社区中行为主体的权利和义务,强化村委会的责任意识和能力建设,加大对违法犯罪行为的排查和惩罚力度,统一建设村民自治空间转向的实现载体。

干式电抗器匝间绝缘状态监测技术综述

干式电抗器由于其参数稳定、损耗小的优点得到广泛应用。但随着干式电抗器的广泛应用,相关事故也随之频繁出现,其中最为常见的是匝间故障。本文首先简要总结了干式电抗器匝间故障产生的原因和机理,随后从不同的角度综述了近年来国内外干式电抗器匝间绝缘状态监测的研究现状,最后基于研究中存在的不足,对干式电抗器匝间绝缘状态监测技术的发展趋势进行了展望。

网络思想政治教育的“技术范式”

网络思想政治教育的“技术范式”,不仅体现为一种理论和实践模式,还体现为一种价值取向和方法论。“技术范式”的建构可以促进网络思想政治教育学科的发展,完善其基本理论与方法,提升其实践能力,实现技术与思想政治教育的深度融合。“技术范式”的建构要处理好技术与人、技术与思想政治教育的关系,使得网络信息技术真正服务于人的全面发展和思想政治教育的现代化转型。“技术范式”的运用能够推动网络思想政治教育方法的革新,提高其技术含量,促进其向精准化、个性化和智能化方向发展,从而提升网络思想政治教育的有效性。

基于成组技术的滚刀复合加工零编程系统开发

针对齿轮滚刀个性化、小批量的需求现状和多工序、低效率的加工现状,利用成组技术原理对齿轮滚刀进行分类,通过分析现存滚刀加工工艺设计车铣复合加工工艺,提出基于成组技术零编程实现滚刀的半成品加工。以整体式滚刀为研究对象,车铣复合机床BHR700V为平台,设计各工序的结构和工艺参数化变量,实现各工序的参数化编程,在西门子SINUMERIK 840d数控系统上开发出齿轮滚刀的定制化人机界面,并在车铣复合机床BHR700V上成功用于滚刀半成品加工。

数控车铣复合机床的编程技术分析

阐述数控车铣复合机床的特点与应用,以及数控机床编程技术的原理。基本原理包括数学模型、语言规范和程序生成。分析数控编程语言的种类及特点、数控编程常见指令的解析与应用、数控编程技术的优化方法。探讨编程技术应用与发展。

A Workable Solution for Reducing the Large Number of Vehicle and Pedestrian Accidents Occurring on a Yellow Light

Traffic intersections are incredibly dangerous for drivers and pedestrians. Statistics from both Canada and the U.S. show a high number of fatalities and serious injuries related to crashes at intersections. In Canada, during 2019, the National Collision Database shows that 28% of traffic fatalities and 42% of serious injuries occurred at intersections. Likewise, the U.S. National Highway Traffic Administration (NHTSA) found that about 40% of the estimated 5,811,000 accidents in the U.S. during the year studied were intersection-related crashes. In fact, a major survey by the car insurance industry found that nearly 85% of drivers could not identify the correct action to take when approaching a yellow traffic light at an intersection. One major reason for these accidents is the “yellow light dilemma,” the ambiguous situation where a driver should stop or proceed forward when unexpectedly faced with a yellow light. This situation is even further exacerbated by the tendency of aggressive drivers to inappropriately speed up on the yellow just to get through the traffic light. A survey of Canadian drivers conducted by the Traffic Injury Research Foundation found that 9% of drivers admitted to speeding up to get through a traffic light. Another reason for these accidents is the increased danger of making a left-hand turn on yellow. According to the National Highway Traffic Safety Association (NHTSA), left turns occur in approximately 22.2% of collisions—as opposed to just 1.2% for right turns. Moreover, a study by CNN found left turns are three times as likely to kill pedestrians than right turns. The reason left turns are so much more likely to cause an accident is because they take a driver against traffic and in the path of oncoming cars. Additionally, most of these left turns occur at the driver’s discretion—as opposed to the distressingly brief left-hand arrow at busy intersections. Drive Safe Now proposes a workable solution for reducing the number of accidents occurring during a yellow light at intersections. We believe this fairly simple solution will save lives, prevent injuries, reduce damage to public and private property, and decrease insurance costs.