全文获取类型
收费全文 | 104篇 |
免费 | 5篇 |
国内免费 | 7篇 |
专业分类
综合类 | 11篇 |
化学工业 | 11篇 |
金属工艺 | 42篇 |
机械仪表 | 1篇 |
建筑科学 | 4篇 |
矿业工程 | 1篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
武器工业 | 1篇 |
一般工业技术 | 14篇 |
冶金工业 | 27篇 |
自动化技术 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 7篇 |
2013年 | 2篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 3篇 |
2007年 | 9篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 13篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1996年 | 2篇 |
1991年 | 1篇 |
排序方式: 共有116条查询结果,搜索用时 15 毫秒
1.
As a solid state joining process, ultrasonic spot welding has been proven to be a promising technique for joining copper alloys. However, challenges still remain in employing ultrasonic spot welding to join copper alloys. This article comprehensively reviews the current state of ultrasonic spot welding of copper alloys with a number of critical issues including materials flow, plastic deformation, temperature distribution, vibration, relative motion, vertical displacement, interface friction coefficient, online monitoring technique, coupled with the macrostructure and microstructure, the mechanical properties and electrical conductivity. In addition, the future trends in this field are provided. 相似文献
2.
Ravi Shanker Vidyarthy Dheerendra Kumar Dwivedi Vasudevan Muthukumaran 《Materials and Manufacturing Processes》2018,33(7):709-717
In the present work, the influence of process parameters such as welding current (I), welding speed (S), and flux coating density (F) on different aspects of weld bead geometry for example depth of penetration (DOP), bead width (BW), depth to width ratio (D/W), and weld fusion zone area (WA) were investigated by using the central composite design (CCD). 9–12% Cr ferritic stainless steel (FSS) plates were welded using A-TIG welding. It was observed that all input variables have a direct influence on the DOP, BW, and D/W. However, flux coating density has no significant effect on WA. Mathematical models were generated from the obtained responses to predict the weld bead geometry. An optimized DOP, BW, D/W, and WA of 6.95?mm, 8.76?mm, 0.80, and 41.99?mm2, respectively, were predicted at the welding current of 213.78 A, the welding speed of 96.22?mm/min, and the flux coating density of 1.99?mg/cm2. Conformity test was done to check the practicability of the developed models. The conformity test results were in good agreement with the predicted values. Arc constriction and reversal in Marangoni convection were considered as major mechanisms for the deep and narrow weld bead during A-TIG welding. 相似文献
3.
介绍了40Mn2钢的特性及用途。结合石钢3#连铸机设备的实际情况,分析了导致40Mn2铸坯低倍内裂的原因。通过优化电磁搅拌参数和振动参数,基本消除了40Mn2钢材低倍内裂的缺陷问题,为连铸设备出现变化时如何保证生产提供了思路。 相似文献
4.
摘要:基于热酸洗腐蚀原理与图像光学理论,提出运用金属低倍组织灰度分析技术(灰度分析法)获取中高碳钢铸坯的低倍组织中不同位置不同区域不同尺度的一维、二维C元素含量分布。偏析严重的位置得到的C元素含量高,初始凝固的晶粒中心位置得到的C元素含量低,说明通过灰度分析法计算的C元素含量分布能与低倍组织形貌很好地对应。同时,通过电子探针与灰度分析法的测量结果对比,发现二者C元素含量的变化趋势具有很好的一致性,这验证了灰度分析法的有效性。另外,低倍组织图像整体亮度的改变不会造成由灰度分析法所测量的C元素含量发生明显改变,则表明灰度分析法对测量环境的变化具有一定的抗干扰能力,也间接说明了其可靠性。 相似文献
5.
ABSTRACTIn this paper, an electromagnetic torque device based on the theoretical model was established to determine the optimum frequency accurately and conveniently in billet and bloom continuous casting with in-mould electromagnetic stirring (M-EMS). Magnetic characteristics with M-EMS was investigated by numerical simulation and physical experiment with the application of electromagnetic torque device and gauss meter. In addition, the effects of stirring frequency with M-EMS on macro segregation and equiaxed crystal ratio were compared and analysed for 55SiCr with 150?mm?×?150?mm billet caster and BU with 310?×?360?mm bloom caster by a series of plant trials, respectively. The results showed that maximum magnetic flux density and maximum electromagnetic torque occurred with different frequency and same current in M-EMS, and central equiaxed crystal ratio and macro segregation has been significantly improved by optimum frequency with M-EMS. 相似文献
6.
7.
8.
《结构钢低倍组织缺陷评级图》GB/T1979-2001是目前国内唯一钢铁型材、扁材低倍组织缺陷评级图,但样品缺陷的大、小与样品规格不成正比。笔者结合标准的修订,阐述了大、小规格评级图间的差异及联系。 相似文献
9.
石英玻璃的结构缺陷及其形成机理 总被引:2,自引:0,他引:2
采用不同工艺制备4种石英玻璃,分析其结构缺陷及形成机理。结果表明,水晶粉为原料、石墨坩埚中熔制的Ⅰ类玻璃气泡、颗粒、条纹最多;高纯SiCl4原料、CVD工艺制备的Ⅲ、Ⅳ类玻璃无颗粒缺陷,气泡与条纹明显少于Ⅰ、Ⅱ类。Ⅱ、Ⅳ类玻璃经高温拉棒形成较大热应力,Ⅲ类玻璃熔体降温速度慢、热应力小。微观结构上,Ⅰ类玻璃金属杂质含量最高,Ⅱ类次之,Ⅲ、Ⅳ类都小于5×10-6。Ⅳ类玻璃在无氢的等离子火焰中熔制、羟基含量极低,Ⅱ、Ⅲ类在H2-O2焰中熔制导致羟基含量高。Ⅰ、Ⅱ、Ⅳ类玻璃氧空位含量较高,Ⅲ类玻璃基本不存在氧空位。 相似文献
10.