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We determine upper and lower bounds for partial sums of subsequences of the dyadic Champernowne sequence, which are obtained from completely deterministic selection functions. This complements results by Shiokawa and Uchiyama.
This paper deals with the preconditioning of the matrix that arises from a H(curl)-conforming finite element (FEM) discretization of an eddy current problem in the frequency domain. Large jumps in the material coefficients may cause serve ill-conditioning. We have investigated how operator preconditioning and hierarchical matrices can be used to construct efficient preconditioners and obtain fast...
Since lead was banned from the solder joints, mechanical tests of microelectronic components and modules have gained much importance not just in mobile electronics but quite in general. The standardized JEDEC drop test is commonly used. It delivers repeatable results for a wide range of loads in the components mounted on the well specified test PCB. As yet the JEDEC drop test is time consuming and...
After surveying the laminate theory, this paper presents a field proven 3-steps concept for modeling printed circuit boards (PCB). First, the behavior of the single plies is studied by means of a 3D detailed model representing a typical cell. Afterwards, the laminate theory is applied to transfer the material data determined in the first step to a 3-layers model, which eventually allows modeling full...
Although there seems to be agreement that the SnAgCu-solder is the lead-free alloy of choice, the basic eutectic SnAgCu system does not fully satisfy the requirements of an alternative to the classic SnPb system. Therefore the question is, how the simple SnAgCu eutectic needs to be changed in order to achieve a higher mechanical performance of the solder. Changes include the increase or reduction...
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