变厚度圆盘的自由扭转振动

本文求出径向线性变厚度圆盘自由扭转振动的弹性动力学理论解,探讨了圆盘的无剪扭振和剪切扭振的特性,并给出不同厚度变化率和内外径比圆盘的固有频率和振型的数字计算结果。     

中厚板圆盘剪剪切力能参数测试及最佳剪刃间隙数学模型的建立

针对中厚板圆盘剪剪切质量差、剪切力理论计算偏差大等问题开展了生产实测、数据采集、回归拟合处理,得出现有的剪切力理论公式计算结果和实测结果相比误差在-9.56%～+56.5%之间.这些理论公式求解中未考虑随着厚度的增加剪切抗力和抗剪面积的非线性变化,导致剪切力计算结果大幅减小.这些公式适宜于薄规格钢板的剪切力计算,但用于厚板剪切力计算还要进一步完善.同时,建立了一个综合剪切钢板厚度、材料属性、累积剪切面积的圆盘剪剪刃间隙调整模型,并且考虑了刀盘装置在剪切受力过程中的变形对剪刃间隙影响.因此,针对不同的圆盘剪设备,要在该模型中考虑刀轴载荷-变形值的影响,对模型进行修正完善,就可获得适合于自己的间隙调整工艺参数.     

中厚板切边圆盘剪的设计与结构分析

本文利用计算机辅助系统,借鉴国外的先进技术,自主设计了国产化的中厚板切边圆盘剪,主要阐述了其结构特征及工作原理,并对主要结构件进行了参数制定分析,剪刃重叠量及侧隙对剪切质量的影响。     

一种碎边剪后废料溜槽的新结构

在各类板带轧制及后处理生产线中,圆盘剪碎边剪后的废料收集普遍采用碎边剪上的废料溜槽直接导入废料箱的方式,本文介绍一种碎边剪后废料溜槽的新结构。其目的是：在碎边剪之后,随着废料车的移动,能最大限度的使用废料箱体的空间,提高其使用效率。     

圆盘剪剪切中板间隙值浅析

圆盘剪剪切钢板过程中,如果能采用合理适合的方法来调整剪切时的间隙,可以保证切过质量,又能使剪刃承受适合的剪切力避免崩刀的风险和减小磨损。因此对剪切中板的间隙值进行攻关优化,确定调整间隙值的规律。     

CPC、EPC系统在硅钢重卷机组上的应用

通过对CPC、EPC系统在硅钢重卷机组的应用,介绍其工作原理,结合实践经验重点描述系统的调试方法,利用CPC系统解决机组圆盘剪只能对称剪切的缺陷问题。     

圆盘造球机刮刀系统改造

本文简单的介绍了圆盘造球机的用途、工作原理,主要针对圆盘造球机中固定刮刀在实际生产中出现的一系列问题进行了分析,提出了刮刀系统的优化方案。实践证明,新结构的刮刀系统的采用可从根本上解决原固定刮刀结构存在的问题。     

双圆盘传感器阵列的声定位系统

声定位技术在许多领域中有着广泛的应用，但大范围、远距离目标的声定位始终是工程实际应用中的一个难题。本文提出了一种平面双圆盘传感器阵列的技术方案，每个圆盘相当于一个矢量传感器，用于测定声目标的方向。本文对该系统的误差来源进行了详细分析，给出了各种误差对定位精度的影响，并进行了仿真实验研究。     

钛薄壁圆盘的无飞边冲压工艺

一般的封头型零件都是冲压成型后再经机加工而成.但对于冲压成型壁厚仅为2 mm的钛圆盘,由于钛塑性好、刚性差,冲压后产生飞边,后续工序困难.为此分析了采用冲压成型制作薄壁钛圆盘而不产生飞边,不须后续精加工的可行性,并制订了多个工艺方案.通过优选建立了无飞边一次冲压成型制作薄壁钛圆盘的工艺,并设计了专用冲压模.采用本工艺及其模具冲压成型的钛圆盘,无飞边、无毛刺、底面平整、盘壁无皱折,且出模容易,变形较小,完全符合图纸设计要求.     

小郑庄南跨渠连续箱梁盘销式支架材料的应用

本研究以小郑庄南生产桥为研究案例,研究了跨渠连续箱梁盘销式支架材料的具体应用,分析了跨支架布设方案,对跨现浇支架检算与圆盘架搭设等具体技术环节进行了研究。     

考虑研磨子——车轮和轮轨作用的城际动车组车轮磨耗预测

针对站间距短、研磨子频繁作用的城际铁路,建立了集车辆系统动力学、研磨子―车轮接触和车轮磨耗等模型于一体的动车组车轮磨耗预测模型,车轮磨耗采用Archard模型计算,实现了研磨子―车轮和轮轨接触对车轮磨耗贡献的定量预测。以中国南方某城际线路上运行的某型城际动车组为例,模拟了动车组车轮LM廓形在一个车轮镟修周期内的演化,通过对比跟踪测试结果,确定研磨子所致车轮磨耗的磨耗系数取1.45×10-4,并完成了模型验证。上述城际铁路的模拟结果显示,该模型的车轮磨耗预测误差仅为5.00%。以0.30 MPa工作气压下的高硬度研磨子为例,发现其最佳工作模式为“工作20 s—停止工作25 s”的间歇式工作模式。为动车组研磨子系统的优化设计提供有效模拟工具。     

Edge detection using Chebyshev's orthogonal polynomial and brain extraction from magnetic resonance images of human head

In this article, we propose a new edge detecting method based on the transform coefficients obtained by a point spread function constructed out of Chebyshev's orthogonal polynomials. This edge detector finds edges similar to that of Prewitt and Roberts but is robust against additive and multiplicative noises. We also propose a new scheme to extract brain portion from the magnetic resonance images (MRI) of human head scan by making use of the of the new edge detector. The proposed scheme involves edge detection, morphological operations, and largest connected component analysis. Experiments conducted by applying the proposed scheme on 19 volumes of MRI collected from Internet Brain Segmentation Repository (IBSR) show that the proposed brain extraction scheme performed better than the popular Brain Extraction Tool (BET). The performance of the proposed scheme is measured by computing the Dice coefficient (D) and Jaccard similarity index (J). The proposed method produced a value of 0.9068 for D and 0.8321 for J.     

三面切书机振动分析的阶次跟踪方法

旋转机械的固有特性导致其在运行过程中会产生振动,当振动过于强烈时,会导致机器工作异常,甚至产生生产事故。如何有效地控制振动,成为工程技术人员的一个重要研究课题。采用阶次分析方法对三面切书机振动进行测试分析,确定振动产生的原因。为进一步的控制和降低三面切书机的振动提供参考和依据。     

Radarsat SAR图像上水稻田边界提取研究

为精确提取Radarsat SAR图像上水稻边界信息，开发了一个二维8方向滤波算法并设计了优化的边界提取方案，将其应用于863－308项目“SAR技术用于南方水稻长势监测与土地利用调查应用示范”研究中，结果表明该算法比用遥感图像处理软件（PCI）提取的水稻田边界更精细，且连续性好，从而在应用中可降低水稻种植面积计算的误差，进一步提高水稻估产的精度。     

Edge enhancement and edge-enhanced correlation with photorefractive polymers

We demonstrate a simple all-optical realization of programmable edge enhancement and edge-enhanced correlation using novel photorefractive polymers. We show that the higher non-Bragg order in a two-beam coupling scheme contains the edge enhancement of the object when placed in the path of one of the incident beams. Also, this arrangement provides a scheme for writing joint transform correlation dynamic holograms, which can be read by a third beam. The correlation is edge enhanced, and the correlation peak increases with the applied bias voltage. Numerical results without and with beam fanning are presented. Theoretical predictions are reconciled with experimental results.     

A Novel Anonymous Authentication Scheme Based on Edge Computing in Internet of Vehicles

The vehicular cloud computing is an emerging technology that changes vehicle communication and underlying traffic management applications. However, cloud computing has disadvantages such as high delay, low privacy and high communication cost, which can not meet the needs of real-time interactive information of Internet of vehicles. Ensuring security and privacy in Internet of Vehicles is also regarded as one of its most important challenges. Therefore, in order to ensure the user information security and improve the real-time of vehicle information interaction, this paper proposes an anonymous authentication scheme based on edge computing. In this scheme, the concept of edge computing is introduced into the Internet of vehicles, which makes full use of the redundant computing power and storage capacity of idle edge equipment. The edge vehicle nodes are determined by simple algorithm of defining distance and resources, and the improved RSA encryption algorithm is used to encrypt the user information. The improved RSA algorithm encrypts the user information by reencrypting the encryption parameters . Compared with the traditional RSA algorithm, it can resist more attacks, so it is used to ensure the security of user information. It can not only protect the privacy of vehicles, but also avoid anonymous abuse. Simulation results show that the proposed scheme has lower computational complexity and communication overhead than the traditional anonymous scheme.     

基于亮度的自适应单尺度Retinex图像增强算法

针对基于Retinex理论的经典图像增强算法中存在的灰化现象、噪声扩大现象和光晕现象,提出一种基于亮度的自适应单尺度Retinex图像增强算法.算法中引入了基于边缘信息的高斯滤波器,主要使用同类性质的像素进行平滑处理用以改善光晕现象和抑制噪声;在提取的反射分量中加入像素的原始亮度以改善灰化现象和减小噪声.对比仿真卖验结...     

泰州大桥中塔墩防船撞研究

泰州大桥主墩位于航道边缘,可能遭受船舶的撞击。为保护大桥,综合考虑多种因素研究大桥中塔墩防船撞方案。针对泰州大桥三塔悬索桥型,结合通航船舶规划、桥梁参数、桥墩基础特点,开展防撞研究,提出针对性防撞方案,进行防撞特性计算分析,确定防撞方案的技术、经济特性。通过有限元数值仿真技术,研究泰州大桥在船舶撞击下的安全性和防撞方案的有效性。     

一种新型的基于数据平面共享环的IP over ASTN机制

提出了一种重叠模型下新型的基于数据平面共享环的IP over ASTN机制,其优点是利用IP网络中路由器自身具备的能力和在ASTN边缘节点引入基于以太网的二层交换能力,以较低的环路带宽代价实现各IP网间可达性信息传达,同时避免了对路由器的基本运行机制的较复杂修改。分析了相应的组网形式、边缘节点结构和网络运行机制,并对其中具有关键意义的带宽限制参数提出两种参数确定算法。     

Robust network coding against path failures

In this study, an approach for robust network coding is introduced for multicast in a directed acyclic network in the presence of network edge failures. The proposed designs aim at combating the resulting path failures, which result in interestingly scalable solutions. A robust network coding scheme (RNC1) is proposed that, devising a rate-path diversity trade-off for the receivers, attains the post-failure capacity of the network with high probability. The scheme is receiver based and can also be applied for correcting random erasures. Next, a rate-guaranteed robust network coding scheme (RNC2) is proposed. The code guarantees the maximum rate for a predetermined number of path failures. The scheme, of course, attains the refined Singleton bound for the edge failure model. A path failure may not necessarily reduce the network capacity, as the remaining intact edges within the network may still facilitate backup paths from the source to the sinks. We introduce RNC3 to employ such backup paths in addition to the original paths and guarantee multicast at a certain rate in the presence of all edge/path failure patterns that do not reduce the capacity below this rate. All the three proposed schemes for multicast are robust to a number of edge failures that may, in general, exceed the refined Singleton bound. Our analyses indicate that the design complexities and the required field sizes grow as a function of the number of network paths, as opposed to the number of network edges because of prior schemes.