全文获取类型
收费全文 | 195篇 |
免费 | 10篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 9篇 |
综合类 | 3篇 |
化学工业 | 41篇 |
金属工艺 | 64篇 |
机械仪表 | 3篇 |
建筑科学 | 5篇 |
矿业工程 | 5篇 |
能源动力 | 5篇 |
轻工业 | 6篇 |
水利工程 | 2篇 |
石油天然气 | 3篇 |
武器工业 | 2篇 |
无线电 | 15篇 |
一般工业技术 | 26篇 |
冶金工业 | 17篇 |
原子能技术 | 2篇 |
自动化技术 | 2篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2017年 | 14篇 |
2016年 | 27篇 |
2015年 | 25篇 |
2014年 | 27篇 |
2013年 | 24篇 |
2012年 | 21篇 |
2011年 | 15篇 |
2010年 | 7篇 |
2009年 | 7篇 |
2008年 | 10篇 |
2007年 | 5篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 3篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有210条查询结果,搜索用时 15 毫秒
201.
为了减小后排乘员在偏置碰撞中受到的伤害,运用MADYMO软件建立包括汽车车身、前后排座椅、三点式安全带、汽车地板、后排5%女性假人的某款汽车后排偏置碰撞的乘员约束系统仿真模型。通过样车试验碰撞结果和模型仿真结果进行对标,验证模型的准确性。在此模型基础上,研究分析前排座椅和安全带等参数对后排乘员安全性的影响,并提出了安全带固定点改进方案,结果表明改进后后排乘员的头部HIC15降低14.2%,颈部张力降低14.4%,有效地保护后排乘员安全。 相似文献
202.
We have studied the effects of Ti underlayer (collimated Ti vs. standard Ti) and Al deposition power (12 KW vs. 6 KW) on the
electromigration (EM) lifetime of bottom-Ti/Al-0.5wt.%Cu/Ti/TiN-top stack. The (002) texture of standard Ti (s-Ti) was stronger
than that of collimated Ti (c-Ti). The Al stack prepared with s-Ti underlayer, which had the stronger Al (111) texture and
more uniform grain size distribution, showed better EM lifetime than the same with c-Ti underlayer, independent of the Al
deposition power. The Al stack prepared with an Al deposition power of 6 KW was also found to show better EM lifetime than
the same with a 12 KW deposition power, independent of the type of Ti underlayer. Longer deposition time for low power sputtering
resulted in the stronger Al (111) texture, larger median grain size, and more uniform Ti−Al reaction layer. Finally, the effects
of Ti underlayer and Al deposition power on the EM lifetime of Al-0.5%Cu films could be well explained by the grain size distribution
and Al (111) texture, which is closely related to the underlying-Ti (002) texture. 相似文献
203.
对Al-25%Si合金采用固溶处理,用金相显微镜分析在不同处理工艺条件的显微组织,并采用image pro-plus软件测定固溶处理后合金组织中初生Si相的尺寸、形态和数量分布。用布氏硬度计测量不同试验条件下试样的硬度,并进行数据分析。通过控制固溶处理温度、固溶时间等工艺参数,最终确定了优化初生硅相的最优工艺条件。 相似文献
204.
基于物理气相沉积(PVD)之直流磁控溅射镀膜技术在低硅钢薄板双面共沉积富Si膜,然后高温真空扩散处理使Si渗入低硅钢基体,提高基体含Si量。以沉积Fe5Si3膜+1 180℃×1h扩散为1回合增Si处理,研究了多回合循环增Si处理过程硅钢基体组织结构与性能的演化机理。采用光学显微镜对样品进行了金相分析,采用扫描电镜(SEM)观察了样品的微观组织形貌,并用能谱分析仪(EDS)进行成分分析。用X射线衍射仪(XRD)和透射电镜(TEM)表征了样品的结构特征。经过4回合循环增Si处理可将0.35mm厚低硅钢基体含Si量由3%提高到6.5%,且沿厚度方向Si浓度分布均匀。相比于初始态低硅钢基片,PVD法制成6.5%Si高硅钢中高频铁损值降低40%~50%。 相似文献
205.
Zhan-yong Zhao Xi-hua Guan Jian Zhang Xiao-ping Sun Hui-Nan Liu 《Materials and Manufacturing Processes》2015,30(10):1223-1228
Electromagnetic stirring induced metal flow and led to homogenous dispersion of TiAl3 particles. Fragmentation mechanism induced by electromagnetic stirring also contributed to TiAl3 particle refining. TiAl3 particle size decreased with the increases of stirring temperature and time. Shearing force among different melt layers under the shear action of roll in the roll-shoe gap increased with the decrease of casting temperature and the increase of melt viscosity, and the fragmentation of TiAl3 phase became obvious correspondingly. Under the optimal process parameters, Al–5Ti–1B(wt.%) alloy wire with excellent inner microstructure and high surface quality was produced. The average sizes of TiAl3 are less than 20 µm, and TiB2 phases are less than 0.5 µm, respectively. Al–5Ti–1B(wt.%) alloy wire manufactured by present method has a high refining ability on pure aluminum and an excellent ability of refining effectiveness. 相似文献
206.
207.
208.
An W-10 wt.%Ti alloy target was prepared by the W-Ti ball-milled powders, and W-Ti thin ?lms were deposited by dc magnetron sputtering on Si substrates. Then Cu/W-Ti/Si structures were prepared after Cu films were deposited on the W-Ti/Si structures. The results show that W-Ti alloy has a single phase structure with fine grain size. The structures of W-Ti thin films evolved from an amorphous film to a dual phase structure with bcc W and hcp Ti, followed by W-Ti solid solution with increasing sputtering powers. W-Ti thin ?lms can effectively block against Cu diffusion and maintain good adhesion strength with Cu ?lms at 600 °C. The failure mechanism of the crystal W-Ti films is related to the grain boundary which provides fast diffusion paths for Cu and Si atoms, while the amorphous W-Ti diffusion barrier layer is directly related to the thermal stress and interface reaction. 相似文献
209.
基于传热模型,计算了直径分别为300、600和900μm的Fe-52%Cu合金微滴在自由凝固条件下的温度场分布,分析了温度梯度的变化及L_(2)相小球动力学特点。结果表明,合金微滴在相分离过程中其中心与表面温差较小(<5 K),而对于给定尺寸的微滴其径向方向上温度梯度却差异较大,但温度梯度值随时间成一次线性减小。通过理论计算,确定了小球在三种微滴内最大可迁移时间,分别是0.0206、0.07和0.141 s。此外,还比较了小球在三种微滴内的迁移距离,发现同尺寸小球在合金微滴内最大迁移距离与微滴半径之比为定值,r/R=0.4849,表明小球在合金微滴内的末态相对位置不依赖于微滴直径。这与目前大部分研究者对合金微滴直径影响核/壳结构形貌的观点有所不同。本研究不仅有助于理解核/壳型粉末的形成过程,同时为新材料设计奠定重要理论基础。 相似文献
210.
《International Journal of Hydrogen Energy》2023,48(42):15879-15893
Blue hydrogen production by steam methane reforming (SMR) with carbon capture is by far the most commercialised production method, and with the addition of a simultaneous in-situ CO2 adsorption process, sorption-enhanced steam methane reforming (SESMR) can further decrease the cost of H2 production. Ni-based catalysts have been extensively used for SMR because of their excellent activity and relatively low price, but carbon deposition, sulphation, and sintering can lead to catalyst deactivation. One effective solution is to introduce additional metal element(s) to improve the overall performance. This review summarizes recent developments on bi/polymetallic catalysts for SMR, including promoted nickel-based catalysts and other transition metal-based bi/polymetallic materials. The review mainly focuses on experimental studies, but also includes results from simulations to evaluate the synergistic effects of selected metals from an atomic point of view. An outlook is provided for the future development of bi/polymetallic SMR catalysts. 相似文献