NdFeB铸块HD工艺中温度和压力对吸氢行为的影响

对NdFeB铸块在HD工艺中温度和压力对吸氢行为的影响进行了研究。研究发现，NdFeB铸块在氢爆过程中明显存在孕育期，其吸氢过程分为四个阶段：孕育期阶段、慢速吸氢阶段、快速吸氢阶段和缓慢吸氢阶段；随着氢气压力(1～4atm)的升高，孕育时间缩短，吸氢越快；随着温度的升高，NdFeB铸块吸氢越迅速，当温度升至一定程度时，孕育期消失。扫描电镜观察发现，NdFeB合金氢爆破碎中的断裂方式包括沿晶和穿晶断裂，氢爆粉末尺寸小于50μm，取得了较好的氢爆效果。     

Research of novel oscillating wire feeding system using the AC servo motor

With the background of the control of additional mechanical force droplet transfer in MIG/MAG welding, regarding the AC servo motor as core, a novel oscillating wire feeding system has been developed with excellent performances of control and dynamic acceleration which is tested. System constitution and operation principle are introduced in this paper. Influences of parameters on dynamic acceleration performance are analyzed and discussed emphatically, such as oscillating frequency, oscillating amplitude and draw-back speed. Experimental result indicates that according to the technique of welding control, the novel wire feeding system responds rapidly to various kinds of control orders of wire feeding and draw-back, and realizes flexible control of welding wire axial movement, including dynamic shifting ,oscillating and so on.     

数控焊接机CNC系统软件的研究与实现

插补软件是ＣＮＣ系统软件的重要部分，本文以自行研制的ＳＫＨＪ－４焊接机８数控系统为例，重点就该焊机ＣＮＣ系统的插补软件，详细讨论了焊接轨迹插补算法理论，以及在ＣＮＣ软件开发方面应考虑的主要问题。     

Effects of temperature and current density on the surface hardness and tribological properties of Ti-6Al-4V alloy by molten salt carburization

Surface hardening of Ti-6Al-4V alloy was achieved by carburization in a molten salt bath containing BaCO₃ as the carbon-yielding agent with electrolysis within the temperature range 790–930°C. The hardness of the total carburizing layer (TCD) is influenced by the bath temperature, the applied current density and the carburizing period. The major hardening effect is considered to be the formation of a solid solution of carbon in -Ti. The oxide film wrapping at the outermost surface of cathodically charged specimens, identified to be mainly BaTiO₃, was formed irrespective of the bath temperature during the quenching process and has no effect on the surface hardening. The optimal carburizing parameters obtained in this study for surface hardening are carburizing at 930±10°C (bath temperature) and 0.3 A/Cm² (applied current density) for 90 min (carburizing period), while those for tribological properties improvement are carburizing at 860±5°C and 0.3 A/Cm² for 90 min.     

新型水下焊接电源及送丝机构的研究

研究了一种新型的水下焊接系统。系统中孤焊电源输出阶梯型的外特性，送丝系统采用脉动送丝方式。在单片机控制下，脉动送丝波形与外特性同步调控。在停止送丝阶段，单片机夸电源输出电压为峰值，焊丝在此电压下返烧并形成熔滴。送丝脉冲到来的瞬间，电源输出电压切换为基值。熔滴依靠送丝动量向熔地方向前进，最终向熔池过渡，随着焊炬的移动而彤成一道焊缝。实验结果表明，使用这个系统进行气体保护药芯焊丝水下湿法焊接时，电压、电流波形均匀工整，短路过渡频率受控，焊接过程稳定，水下焊缝成形较为美观。     

锆-4合金低周疲劳断口裂纹扩展能量及分形特征研究

对锆-4合金低周疲劳裂纹扩展过程进行了探索性的研究。通过分析锆-4合金低周疲劳断口在裂纹扩展方向上能量及分形维数变化趋势，发现锆-4合金动态裂纹扩展中扩展期由3个阶段组成，每一阶段的能量和分形维数都不同。A-B段的能量最小，归一化值为0-0．0156，A-B段的分形维数居中，在工工方向均值为2．2796，标准差为0．0277，在LH方向均值为2．4516，标准差为0．0592。D-E段能量远大于A-B段，归一化值为0．8754～0．9652，但分形维数最小，LL方向均值为2．2214，标准差为0．0131，LH方向均值为2．3477，标准差为0．0550。F-H（或G-H）段能量最大，归一化值达到1，同时分形维数也达到最大，LL方向均值为2．3414，标准差为0．0704，LH方向均值为2．5398，标准差为0．0263。虽后，根据二次电子成像原理以及锆-4合金低周疲劳断口的形貌特征对此现象进行了初步分析。     

高新技术企业薪酬体系设计原则分析

高新技术企业区别于传统企业的特殊性 ,决定了其激励—约束机制需要在很大程度上进行创新 ,所以传统的一些薪酬制度已经不适合高新技术企业的发展。本文首先探讨了高新技术企业本身及其人才的特点 ;然后在此基础上阐述了高新技术企业在薪酬体系设置的过程中应注意的三个原则 :股权激励性、阶段性和多重性     

2014年灵丘春玉米生育期气象条件分析

根据灵丘县2014年4月下旬到9月下旬的气象观测资料和玉米获得高产所需的农业气象条件,对灵丘县春玉米生育期的气象条件进行了综合分析,得出2014-04—09的综合气象条件能满足春玉米生长发育的需求。其中,有3个时段的气象条件与春玉米生育阶段的需求不吻合,即5月上旬出现冷害、7月中下旬降水偏少、9月出现阶段性低温和阴雨寡照天气,这些不利气象条件都会对春玉米的发育造成不同程度的影响。     

Switching adaptive learning control for nonlinearly parameterized systems with disturbance of unknown periods

In this paper, a logic‐based switching adaptive learning control mechanism is proposed for a class of nonlinearly parameterized systems with disturbance of unknown periods. The switching algorithms include two parts: one is to stabilize the nonlinearly parameterized uncertainties, the other is to learn the periodic bounded disturbance. An adaptive control method with fully saturated periodic adaptation law is presented to take advantage of the periodic and bounded property of the disturbance. It is shown that under the proposed control designs, the asymptotic convergence is ensured irrespective of initial conditions with all the signals in the closed‐loop system bounded. An illustrative example is given to show the validity of the switching adaptive learning control. Copyright © 2014 John Wiley & Sons, Ltd.     

丹江口大坝加高施工期安全度汛方案

丹江口大坝加高工程施工将对工程度汛带来较大影响,包括新老混凝土施工、施工机械安装布置、施工交通运输以及金结机电设备运行等对施工度汛的影响。根据工程特点并结合现场实际情况,采用了多跨全钢结构栈桥度汛方案。详细介绍了2006~2013年安全度汛方案,包括施工要求和闸门启闭设备的工作情况。经过实际运行和监测,施工度汛栈桥工作性能良好,各指标均在设计控制范围内;保证了施工工期,确保了工程安全度汛。