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141.
波峰焊接工艺技术的研究 总被引:1,自引:0,他引:1
鲜飞 《电子工业专用设备》2009,38(2):10-14
介绍了波峰焊接技术的原理,以及一种新型波峰焊接技术的特点,与传统波峰焊情况不同,它可以保护表面贴装元件来实现对通孔元件焊接。并分别从焊接前的质量控制、生产工艺材料及工艺参数方面探讨了提高波峰焊质量的有效方法。 相似文献
142.
本文介绍了选择性焊接的概念、特点、分类和使用工艺要点。选择性焊接是现代组装技术的新概念.它的出现促进了SMT(表面贴装技术)的发展.并为PCB设计者提供了新的工艺选择。可以确信选择性焊接将会被更多地应用于电子组装上,成为一种具有竞争力的焊接技术。 相似文献
143.
Within electronic products, solder joints with common interfacial structure of Cu/IMCs/Sn-based solders/IMCs/Cu cannot be used under high temperature for relatively low melting points of Sn-based solders (200–300 °C). However, there is a trend for solder joints to service under high temperature because of the objective for achieving multi-functionality of electronic products.With the purpose of ensuring that solder joints can service under high temperature, full Cu3Sn solder joints with the interfacial structure of Cu/Cu3Sn/Cu can be a substitute due to the high melting point of Cu3Sn (676 °C). In this investigation, soldering process parameters were optimized systematically in order to obtain such joints. Further, interfacial microstructure evolution during soldering was analyzed. The soldering temperature of 260 °C, the soldering pressure of 1 N and the soldering time of 5 h were found to be the optimal parameter combination. During soldering of 260 °C and 1 N, the Cu6Sn5 precipitated first in a planar shape at Cu-Sn interfaces, which was followed by the appearance of planar Cu3Sn between Cu and Cu6Sn5. Then, the Cu6Sn5 at opposite sides continued to grow with a transition from a planar shape to a scallop-like shape until residual Sn was consumed totally. Meanwhile, the Cu3Sn grew with a round-trip shift from a planar shape to a wave-like shape until the full Cu3Sn solder joint was eventually formed at 5 h. The detailed reasons for the shape transformation in both Cu6Sn5 and Cu3Sn during soldering were given. Afterwards, a microstructure evolution model for Cu-Sn-Cu sandwich structure during soldering was proposed. Besides, it was found that no void appeared in the interfacial region during the entire soldering process, and a discuss about what led to the formation of void-free joints was conducted. 相似文献
144.
Techniques to improve solder joint reliability have been the recent research focus in the electronic packaging industry. In this study, Cu/SAC305/Cu solder joints were fabricated using a low-power high-frequency ultrasonic-assisted reflow soldering approach where non-ultrasonic-treated samples were served as control sample. The effect of ultrasonic vibration (USV) time (within 6 s) on the solder joint properties was characterized systematically. Results showed that the solder matrix microstructure was refined at 1.5 s of USV, but coarsen when the USV time reached 3 s and above. The solder matrix hardness increased when the solder matrix was refined, but decreased when the solder matrix coarsened. The interfacial intermetallic compound (IMC) layer thickness was found to decrease with increasing USV time, except for the USV-treated sample with 1.5 s. This is attributed to the insufficient USV time during the reflow stage and consequently accelerated the Cu dissolution at the joint interface during the post-ultrasonic reflow stage. All the USV-treated samples possessed higher shear strength than the control sample due to the USV-induced-degassing effect. The shear strength of the USV-treated sample with 6 s was the lowest among the USV-treated samples due to the formation of plate-like Ag3Sn that may act as the crack initiation site. 相似文献
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148.
无铅化是国际电子整机业发展的必然趋势,无铅制程的导入给企业带来新的挑战与机遇。针对无铅化电子组装带来的问题给出了相应的解决方案,其中包括无铅化生产实施步骤、物料与设备的选择、工艺的制定、有毒有害物质的检测及运行成本等。 相似文献
149.
基于加热因子的回流曲线的优化与控制 总被引:1,自引:0,他引:1
回流焊形成的焊点质量与回流焊过程密切相关。基于加热因子Qη对回流焊接过程进行优化控制。根据焊点疲劳寿命随加热因子分布的特点,提出了对冷点加热因子取最优范围下限值控制策略(冷点代表回流过程中经历的加热因子最小焊点),以使所有焊点的加热因子尽可能都在最优范围之内。冷点下限控制策略满足了大部分焊点的高可靠性,而少部分超出最优范围上限的焊点的可靠性虽略微下降,仍可形成良好焊接。由于加热因子理论不对回流曲线形状做严格要求,定义了两个组合参数:形状参数Ht和移动参数Hb,对冷点的加热因子进行控制。并且根据统计学原理利用实验建立Qη与Ht和Hb的回归关系,发现Qη与Ht、Qη与Hb大体上成线性关系,其为Qη的预测和控制带来了极大的便利,从而使焊接可靠性易于得到保证。 相似文献
150.
讨论TSnAgCu305焊料和cu焊盘在不同回流时间下形成的金属间化合物的厚度和形貌,以及焊点内部的组织结构.通过剪切试验测得不同回流时间下得到的焊点强度.试验结果表明:回流时间较短时,IMC层的厚度随着时间的增大快速增长,随着时间推移最后IMC的厚度在5 μm左右趋于稳定.焊点内部的组织形貌随着时间变化由等轴晶到枝状... 相似文献