Technical Library | 2019-05-31 14:19:24.0
ACI Technologies (ACI) characterized the reliability of surface mount RF components. The RF frequency band of interest was the X band (10.7 to 11.7GHz). A two pronged test for reliability of circuit card assemblies (CCA) was designed for both extreme thermal cycling and vibration. The rapid thermal cycling and extreme vibration testing simulates the total stress encountered by the assembly over the life of the product but accomplishes it in a relatively short period of time. In order to perform the reliability testing, a test vehicle consisting of a printed circuit board with test structures and components, was designed, fabricated, and assembled at ACI.
Technical Library | 2010-10-07 20:20:58.0
Evolution from cell phones with only a base-band processor and limited memory to today's high-end phones with an additional applications processor and memory has driven the industry to 3-D packaging solutions. 3-D packaging can be achieved via die stackin
Technical Library | 2014-05-01 15:14:12.0
Bilayer graphene has been a subject of intense study in recent years. The interlayer registry between the layers can have dramatic effects on the electronic properties: for example, in the presence of a perpendicular electric field, a band gap appears in the electronic spectrum of so-called Bernal-stacked graphene. This band gap is intimately tied to a structural spontaneous symmetry breaking in bilayer graphene, where one of the graphene layers shifts by an atomic spacing with respect to the other. This shift can happen in multiple directions, resulting in multiple stacking domains with soliton-like structural boundaries between them
Technical Library | 2021-11-03 16:36:36.0
Laser reflow soldering is an important technology in electronic components processing. In this paper, we presented a simple but efficient method to achieve reflow soldering process with gradient energy band created by just two parallel mirrors. The detailed influence of the variety of optical parameters on the soldering process has been analyzed by using the finite element method. And the modulation of the optical parameters on reflow soldering parameters also has been demonstrated. In our experiment, one HR mirror and one-mirror with transmissivity of 10% have been used to create a gradient energy band with an incident laser power of 50W. In summary, both the simulations and the experiments show that the typical reflow soldering profile has been acquired by the optical system. The high quality joints on both the front and rear surface of the capacitor can be acquired by just one surface radiation of the optical system.
Technical Library | 2015-03-19 20:33:34.0
Silicon is arguably the best electronic material, but it is not a good optoelectronic material. By employing first-principles calculations and the cluster-expansion approach, we discover that hydrogenated bilayer silicene (BS) shows promising potential as a new kind of optoelectronic material. Most significantly, hydrogenation converts the intrinsic BS, a strongly indirect semiconductor, into a direct-gap semiconductor with a widely tunable band gap. At low hydrogen concentrations, four ground states of single- and double sided hydrogenated BS are characterized by dipole-allowed direct (or quasidirect) band gaps in the desirable range from 1 to 1.5 eV, suitable for solar applications. At high hydrogen concentrations, three well-ordered double-sided hydrogenated BS structures exhibit direct (or quasidirect) band gaps in the color range of red, green, and blue, affording white light-emitting diodes. Our findings open opportunities to search for new silicon-based light-absorption and light-emitting materials for earth-abundant, high efficiency, optoelectronic applications.Originally published by the American Physical Society
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