Study on the resistance spot welding technology of 22MnMoB hot stamping quenched steel

In this paper, the spot welding technology of a new kind of 22MnMoB hot stamping quenched steel sheet was systematically studied by power frequency spot welder. Through a series of technology and test experiments, we have obtained the optimal spot welding technological parameter condition. According to the results, the relations among spot welding technological parameter, welding nugget, mechanical property and fracture mode were discussed. The effects of all the welding parameters such as welding current, welding time and electrode force on the quality of joint can be boiled down to one thing--the diameter of welding nugget. The experimental results showed that welding nugget diameter determines the mechanical property of spot welding joint and the relation between welding nugget diameter and the mechanical property of joint presents a kind of linear mathematic representation. There are two typical fracture models of 22MnMoB hot stamping quenched steel sheet, i.e., interracial fracture and nugget pullout. Other than mild steel or normal high strength steel, in the shearing tensile test, hot stamping quenched steel has a great tendency to fail in interfacial mode due to the effects of high strength matrix structure, welding soft zone and the porosity level of fusion zone.     

免疫遗传PID在工业自动化通用平台上的实现

针对目前免疫遗传PID在工程应用中存在的问题,采用图形化组态技术,在工业自动化通用技术平台IAP上实现基于在线免疫遗传算法的PID控制器组态,通过仿真实验分析了免疫遗传PID在阶跃响应和扰动情况下的性能指标.仿真实验结果表明,IAP平台上的免疫遗传PID具有与MATLAB相同的控制性能和控制效果,说明在IAP平台上实现先进控制算法的可行性和有效性.利用IAP兼容包括PLC在内的多种控制站等优点,可以把控制逻辑组态下载到实际的工业控制中,实现免疫遗传PID应用的通用性.     

基于激光扫描共焦显微技术的刀具刃口精密测量

为表征刀具刃口结构,提出了一种刃口精密测量和数据处理方法.采用激光扫描共焦显微镜对刀具刃口进行精密测量,通过数据后处理拟合刃口圆弧半径.研究结果表明:测量采用的角度块倾角会对刃口测量范围及刃口不对称度判定产生影响,应根据刀具结构参数合理选择,对于TPMT16T304刀具选择倾角为50.5°的角度块时测量效果较好;数据平滑可以有效去除测量噪声,提高数据处理效率和测量精度;刀具刃口最小二乘拟合结果与扫描电镜法测量值及标称值较吻合,标准不确定度优于0.084μm.以上结果说明,基于激光扫描共焦显微技术的刀具刃口测量方法简便、测量精度高且不破坏刀具.     

基于评价主体的教育网络游戏评价体系探究

教育网络游戏作为一个独立的新生事物,近年来得到了长足的发展,但其评价方面的研究仍然比较薄弱。从不同的评价主体,能够评价的内容及专业程度不同的视角出发,探究并设计了教育网络游戏的评价体系,并且讲解了该如何具体操作。     

入海河口退化生境阶梯式生态修复策略构想

基于河口生态系统的结构与功能,结合近年来中国主要河流入海污染物的主要种类及含量,提出入海河口生境阶梯式生态修复策略,主要包含:河口"上游段—中游段—下游段"纵向阶梯式生态修复技术体系;河口各段"潮上带—潮间带—潮下带"横向阶梯式生态修复技术体系;污染物在河口从上至下各段(上游段—中游段—下游段)各带(潮上带—潮间带—潮下带)阶梯式消减技术体系;"污染物源头处理—河口污染物生态修复"阶梯式生态修复技术策略。并对这些策略给予理论论证,为构建入海河口生态修复技术体系,消减陆源污染物经河口进入海洋提供新思路。     

河南典型县域农用地产能及潜力研究

以耕地质量等级成果为基础,利用农用地产能核算理论和技术方法,核算了辉县市农用地的理论产能、可实现产能和实际产能.并根据辉县市的粮食生产特征,计算和评价其农用地利用潜力.结果表明:1)辉县市理论单产28 972 kg/hm2,各乡镇之间差别不大;辉县市可实现单产为17 381.72 kg/hm2,各乡镇之间可实现单产存在较明显差异;辉县市农用地实际总产能的计算结果为54.99万t,与统计年鉴产量基本一致;实际单产为12 752.54 kg/hm2,且南部平原区的实际产能高于西北部山区.2)辉县市各行政村的农用地单产利用潜力为1 426.85~7 621.66 kg/hm2,均值为4 628.41 kg/hm2;辉县市农用地总产利用潜力为19.97万t,占整市实际产能的36.29%,其农用地总产具有较大的发展空间.     

基于旅游非优区理论的森林公园旅游发展探讨——以陕西省翠峰山森林公园为例

基于旅游非优区理论,探讨了旅游非优区研究进展、优化路径,以陕西省翠峰山森林公园为例,分析了翠峰山的非优表现,总结出由"生态、创新、主题、本土、休闲、体验"六环节构成的公园旅游优化发展模式.森林公园非优区的旅游发展应突破传统的资源导向模式,结合市场需求与特点,以休闲经济和度假旅游为导向,合理定位、重新组合,开发休闲旅游资源,打造差异化的特色旅游产品;营造独树一帜的休闲度假环境;走出特色化的旅游管理与服务;塑造品牌化的旅游文化与形象,走不仅仅依靠资源的多向发展之路.     

铲齿凸轮理论廓线的设计研究

以铲齿凸轮理论廓线为研究对象,对其设计方法进行了深入研究,提出Hermite型的凸轮回程曲线设计.简要叙述了利用铲齿车床加工齿轮滚刀铲背曲面的基本原理.基于微分几何学和Hermite多项式插值理论,并结合曲线边界条件,给出了三次Hermite型回程曲线的参数方程.结合铲齿凸轮设计实例,比较Archimedes型和Hermite型回程曲线的运动特性曲线,并分析其对加工过程的影响,证明Hermite型曲线的优势.为提高设计效率,用C语言编写铲齿凸轮理论廓线辅助设计程序,并结合开源程序包gnuplot和LaTeX,以曲线图呈现设计结果.     

Progress in the research of radical anion ligands and their complexes

Recent progress in the research of radical anion ligands and their complexes with metals were summarized in this review. Radical anions were sorted into several types including iminosemiquinonate and iminoquinonate radical, nitroxide radical, heterocycle radical etc. Structural characteristics and properties of the corresponding complexes were introduced. The complexes exhibited novel properties and possibility for applications in organic magnetic materials and transition metal catalysis.     

Observation of directional change of core field inside flux ropes within one reconnection diffusion region in the Earth’s magnetotail

Two consecutive magnetic flux ropes, separated by less than 30 s （△t 〈 30 s）, are observed within one magnetic reconnection diffusion region without strong guide field in the Earth＇s magnetotail by Cluster multispacecraft. The flux ropes are characterized by bipolar signatures of the south-north magnetic field component Bz accompanied with strong core magnetic field By, intense current J and density depletions inside of them. In spite of the small but non-trivial global scale negative guide field （-By）, there exists a directional change of the core fields of two flux ropes, i.e., -By for the first one, and ＋By for the second one. The directions of the core fields are the same as the ambient cross-tail magnetic field component （By） just outside of flux ropes. Therefore, we suggest that the core field of flux ropes is formed by compression of the local preexisting By and that the directional change of core field is due to the change of local preexisting By. Such a change in ambient By might be caused by some microscale physics.