脉冲MIG焊接电弧的闭环控制

作者研究成功了一种用于脉冲MIG焊接电弧的闭环控制系统,称为QH-ARC-102控制法。它具有优异的静态及动态品质。无论脉冲或者维弧阶段,电弧的工作点均位于三极管焊接电源阶梯形外特性的恒流段上。因此,电弧稳定,始终保持喷射过渡,飞溅极少,电流的调节范围也较宽广.在每个脉冲期间,均对弧长讯号进行采样以实现对弧长的闭环控制。因此电弧具有很强的抗弧长干扰能力,而且其脉冲工艺参数能够自动优化,可以适应送丝速度大范围的突变。本控制系统对脉动送丝或程序送丝MIG 焊接新工艺比较适用。如用于实现全位置焊接、焊缝成型控制、线能量控制以及熔深的闭环自动控制等,特别是对机器人焊接更为适用。文章论述了本系统的工作原理,介绍了实用的电路图,并且给出了一些焊接结果。     

Ti和V对Fe中氢与位错交互作用的影响

研究了Fe-0.5wt-%Ti和Fe-0.5wt-%V合金中由氢与位错交互作用所形成的氢致冷加工内耗峰(H-CWP)。实验结果表明:合金元素对H-CWP、对氢与位错之间的交互作用有显著的影响,与氢作用愈强的元素,对H-CWP的影响愈大,内耗实验结果与力学性能之间存在着一定的联系.     

加入WTO给当代大学生带来的若干思考

入世对大学人才培养目标、社会人才需求、大学生知识结构、学习理念、就业市场等提出了新的要求，当代大学生必须提高自身的综合素质，培养创新能力，开阔国际视野，重视非智力因素的培养等，以此来适应WTO对人才的需求。     

Meaningful (2, infinity) secret image sharing scheme based on flipping operations

In this paper, a new method to construct a secret image sharing (SIS) scheme is proposed, where a secret image is shared into several shares by a perfect secure way without any knowledge of cryptography. A basic algorithm implemented by flipping operations with probability for constructing a meaningful (2, 2) SIS scheme is first proposed. Neither codebook tailor-made requirement nor pixel expansion is required in the proposed scheme. Additionally, the meaningful shares by the proposed scheme can be directly generated without any extra data hiding process. During the decrypting procedure, the secret image is visually revealed by performing XOR operations on two meaningful shares. In the following stage, a meaningful (2, infinity) SIS scheme is extended underlying the basic algorithm, where the number of shares can be extended anytime. Further, no matter how large the number of the extended shares is, the visual qualities of both the meaningful share and revealed secret image remain unchanged. Finally, sufficient number of formal proofs are provided to validate the correctness of the proposed schemes, whose superiority is also demonstrated by the experimental results.     

运营商发展行业云计算研究

介绍了目前我国云计算发展现状,结合运营商的能力,提出云计算下一步发展建议,并以物流行业作为案例分析具体的解决方案,最后对下一阶段运营商云计算发展进行展望.     

关于网络安全问题的研究

信息网络所涉及的领域是全方位的,其还涉及到了国家政府的相关领域信息,其能够存储和处理诸多政府信息,国家机密信息也不例外,所以世界各地对网络信息造成人为攻击已经在所难免。使用计算机进行犯罪行动很难会留下证据,这一特点也对计算机高技术犯罪情况的发生产生了刺激因素。计算机技术的飞速发展,也带来了计算机犯罪率的提升,网络安全面临着巨大的威胁,特别是近年来,甚至已经发展成为一种严重的社会问题。针对实际中所存在的诸多问题,本文将展开分析并提出相关建议。     

Structural damage identification by adding virtual masses

This paper presents a method for damage identification by adding virtual masses to the structure in order to increase its sensitivity to local damages. The main concept is based on the Virtual Distortion Method (VDM), which is a fast structural reanalysis method that employs virtual distortions or pseudo loads to simulate structural modifications. In this paper, the structure with an added virtual mass is called the virtual structure. First, the acceleration frequency response of the virtual structure is constructed numerically by the VDM using local dynamic data measured only by a single excitation sensor and a single acceleration sensor. Second, the value of the additional mass is determined via sensitivity analysis of the constructed frequency responses of the virtual structure with respect to damage parameters; only the natural frequencies with high sensitivity are selected. This process is repeated for all the considered placements of the virtual mass. At last, the selected natural frequencies of all the virtual structures are used together for damage identification of the real structure. A finite element (FE) model of a plane frame is used to introduce and verify the proposed method. The damage can be identified precisely and effectively even under simulated 5 % Gaussian noise pollution.     

关于Dex/Ucs自动售货机的通信研究①

介绍了基于Dex／Ucs自动售货机通信系统,并根据Dex特点及其通信原理,在Vb6＋Borland平台上,实现了终端与售货机间通信及数据的采集。此系统的核心为终端与系统间的通信。根据Dex会话层的三次握手来实现通信双方的连接,其中所传输数据遵循Dex协议的格式被封装。系统基于Vb6＋C的模式,利用两者的优势被实现。     

基于RFID的人力和资产管理系统

为应对现下各大IT外包服务公司日益扩张的业务量所带来的成本压力,以及因服务网点分散所带来的资讯问题,并积极有效地分配IT服务人员,设计了一种基于云计算中SaaS概念、物联网概念,并合理运用现有RFID,GSM技术的人力和资产管理系统,旨在实现快速有效的人力资源调度以及方便快捷的物资信息管理。阐述了系统的组成结构,并进行了硬件和软件上的设计。项目结果证明该系统具有可行性和实用性。