Effect of Electromagnetic Stirring on the Quality of K417 Superalloy Ingots

The effect of electromagnetic stirring on the inner quality of K417 superalloy ingots is studied with EPMA and optical microscope.The results show that while an electromagnetic stirring with 50Hz frequency and 80A current is imposed,the equiax crystals of K417 superalloy ingots can be effectively refined and increased,and the central shrinkage porosity and the dendritic segregation of K417 superalloy ingots are greatly reduced,so the inner quality of K417 superalloy ingots is obviously improved.     

营造服务营销中的"真实瞬间"

随着服务业的迅猛发展,服务企业间的竞争日趋激烈,提供优质服务已成为企业管理者越来越重视的问题。通过从服务特点中的不可分离性入手,确立了“真实瞬间”的概念,并由此提出了服务性企业提高服务质量的对策。     

星载GPS数据质量控制方法研究

针对星载全球定位系统（GPS）数据的特点,分别从阈值设置和周跳检验量的角度对TurboEdit方法进行改进,并在传统抗差估计方法的基础上,提出一种改进的抗差估计策略。利用GRACE卫星的星载GPS观测数据对本文的质量控制方法进行分析验证,结果表明：改进的质量控制方法能明显增强周跳探测性能,有效抑制小周跳和粗差的影响,提高几何法定轨的精度和可靠性。     

加强过程控制提高风洞实验质量

结合风洞实验的过程控制,概述了过程方法的内涵、风洞实验过程的三个阶段、风洞实验过程控制的要点以及实施规范化管理和落实岗位责任制的看法和建议。     

浅论软件项目管理中的质量保证

质量保证在软件项目管理中能够起到积极、重要的作用,质量保证活动的执行效果直接影响到项目的质量甚至项目的成败。本文结合某公司实施CMM二级评估和软件项目经验,论述了在软件项目管理中实施质量保证的方法、内容和要求,并提出质量保证工作与软件过程的持续改进相辅相成以促进软件项目管理水平的提高。     

电阻点焊质量评判初探

在大量实验数据基础上，利用回归分析法构造了基于热量和电极压力的电阻点焊质量评判数学模型。在点焊过程参数变化情况下，用该数学模型，能有效地对焊点质量进行初级评判。     

基于P～t曲线的导弹火工品品质测试

为了提高导弹火工品的存贮安全性和使用可靠性 ,提出了一种基于P～t(压力 -时间 )曲线获取的火工品品质测试分析方案 ;利用凌华高性能数据采集卡PCI- 9112采集爆炸过程的瞬态压力信号 ,并在对采集到的信号进行频谱分析和在滤波的基础上提取出了火工品的特征参数 ,从而为火工品的品质评判提供了决策参考。     

A real-time combined quality control method for GNSS precise positioning in harsh environments

Global Navigation Satellite System (GNSS) precise positioning can be significantly affected by severe multipath effects and outliers in harsh environments, and highly relies on quality control strategies. Previous studies mainly focus on the posterior residuals to check and exclude the outliers in GNSS observations, limited work emphasizes the combined quality control method considering both the prior and posterior knowledge simultaneously. This paper proposed a real-time combined quality control method to process the multipath effects and outliers in harsh environments simultaneously. Specifically, in the prior stage, a modified multipath processing strategy is proposed for both phase and code observations, then a modified detection, identification, and adaptation (DIA) method considering the maximum times of data snooping is studied in the posterior stage. Two dedicated experiments in real harsh environments were carried out to evaluate the performance of the proposed combined quality control method. For the static experiment, the proposed method exhibits smaller positioning errors, the best positioning accuracy, and the highest availability in this study. Specifically, the proposed method exhibits an improved percentage of 55.4 %, 56.3 %, and 59.7 % for positioning accuracy compared to those without the quality control method in the E, N, and U directions, respectively. Besides, the proposed method can further improve the performance of ambiguity resolution with an improved percentage of 32.2 %. For the kinematic experiment, the three-dimensional positioning accuracy of the proposed method is 0.577 m, which exhibits a 40.0 % improvement compared to those without the quality control method. Also, the proposed method exhibits better performance under relatively strong multipath effects. In this sense, the proposed real-time combined quality control method is highly appreciated in terms of positioning availability, accuracy, and ambiguity resolution for GNSS precise positioning, especially in harsh environments.     

碳／环氧复合材料弹翼的质量控制

影响碳／环氧复合材料弹翼的质量因素较多，而且很复杂。本文着重介绍了弹翼在试生产过程中，不断改进工艺方法以及工艺装备，使复合材料弹翼质量得到了有效控制，各项技术指标均满足了设计和使用要求。