Gas metal arc welding of high nitrogen stainless steel with Ar-N2-O2 ternary shielding gas

High nitrogen stainless steel with nitrogen content of 0.75％was welded by gas metal arc welding with Ar—N2-O2 ternary shielding gas. The effect of the ternary shielding gas on the retention and improvement of nitrogen content in the weld was identified. Surfacing test was conducted first to compare the ability of O2 and CO2 in prompting nitrogen dissolution. The nitrogen content of the surfacing metal with O2 is slightly higher than CO2. And then Ar—N2-O2 shielding gas was applied to weld high nitrogen stainless steel. After using N2-containing shielding gas, the nitrogen content of the weld was improved by 0.1 wt％. As N2 continued to increase, the increment of nitrogen content was not obvious, but the ferrite decreased from the top to the bottom. When the proportion of N2 reached 20％, a full austenitic weld was obtained and the tensile strength was improved by 8.7％. Combined with the results of surfacing test and welding test, it is concluded that the main effect of N2 is to inhibit the escape of nitrogen and suppress the ni-trogen diffusion from bottom to the top in the molten pool.     

Trajectory predictions of new lift separation sabots

This paper presents a modified analytical model to evaluate the trajectories of various lift separation sabot configurations. The aerodynamic forces acting on the sabot surfaces during a supersonic flight are modeled in the present analytical model by incorporating the pressures on the windward side of the sabot due to the detached/attached shock and its reflections and then integrated using the 3-DoF dynamical equations. The trajectory and the aerodynamic coefficients were obtained for these config-urations at a projectile Mach number of 3. The sabot configurations, which include two new designs, are compared with each other and with the conventional free flight trajectory data of the conventional sabots. The mechanical interaction between the sabot and projectile is also addressed in the present work. The comparison shows that the new designs with the aerodynamic surfaces close to the center of gravity, lift-off from the projectile with minimal mechanical interaction compared to a conventional sabot.     

铁谱技术及其在机械监测诊断应用的机理研究

简要分析了磨粒监测技术的几种方法,并对各种监测技术的原理、特点、适用范围进行了评述和比较。在文中系统论述了铁谱分析技术的基本原理及在磨粒监测分析中的重要意义;是应用磁场将润滑剂中磨损颗粒进行分类并计数的一种技术,对铁谱片上磨损碎片的观测能够诊断引起非正常磨损的起因和机械部件磨损的真实情况,常用来检测非正常磨损、磨损方式和磨损的程度,为预测磨损部件的使用寿命提供基本信息,从而使油液的监测分析结果更为全面和准确。     

自航式鱼雷发射装置发射管长度优化研究

基于某型鱼雷自航发射的内弹道数学模型,选择自航管的总长度作为优化目标,讨论了约束函数的取值,确定了优化问题的数学表达.采用惩罚函数法进行寻优计算,针对约束函数具有不可微和非线性的特点,采用模式搜索算法进行了无约束优化的求解,给出了优化结果并进行了比较.     

公安现役部队院校建构心理调控机制探析

当前公安现役部队院校开展心理调控工作日益成为人们关注的焦点,它关系到和谐警营的创建、学员心理品质的优化和部队战斗力的提高等重大现实问题。为此,必须建构公安现役部队院校心理调控机制,从领导、内容、管理和运行等方面规范公安现役部队院校的心理调控工作,以促进公安现役部队院校的全面建设。     

建立定期交流机制促进武警院校教学改革发展

武警院校是武警部队人才培养的重要基地,多年来为武警部队输送了一大批指挥和技术人才。新时期武警部队任务特点的转变,对武警院校教学改革提出了更高的要求。建立武警院校与武警部队、武警院校之间、武警院校与解放军院校以及与地方高校之间多方位、多层次的定期交流机制,对武警院校教学改革具有重要意义。     

中国收费公路制度改革的利益机制设计

收费公路是我国市场化改革延伸到基础设施的重大举措。收费公路已经被作为一种商品在向市场提供,且公路特殊性,使得收费公路产业具有明显的自然垄断性。在公路收费定价优势信息的主导下,在收费公路定价方面通行者处于明显劣势地位。本文希望通过利益机制的设计来提升通行者在收费公路定价博弈中的地位,通过利益机制设计中的激励与约束使公路收费定价者会倾向于选择更公平、公正的价格。     

在依法从严治校中加强院校正规化建设

依法从严治校,是体现现代教育思想和遵循军事教育规律的办学之道,是一种先进高效的管理模式。武警院校在调整改革中,必须始终坚持从严治警、依法从严治校,不断提高院校正规化建设水平。     

移动式综合避雷装置防雷机理与应用

针对石油库重点设施设备的防雷保护特点,提出运用移动式综合避雷装置对油库不同区域进行雷电机动防护。分析了移动式综合避雷装置系统的组成和特点,并应用于实践。移动式综合避雷装置应用于某油库一些重点区域的综合防雷实践中,具有安全、可靠、实用、方便等特点,值得推广应用。     

基于反馈机制的武器装备体系作战能力聚合方法

武器装备体系作战能力聚合对武器装备体系的发展、建设和运用具有重要意义。针对武器装备体系的整体涌现性和作战能力要素的非线性特性,对能力指标间的反馈机制进行研究,提出了一种基于反馈机制的武器装备体系作战能力聚合方法,并通过对某侦察情报装备体系的作战能力聚合算例分析,验证了方法的有效性。