1,606 research outputs found
Reduction of cavity-to-cavity power/ground noise coupling through plane cutout in multi-layer PCBs
No full textAnalysis and suppression of SSN noise coupling between power/ground plane cavities through cutouts in multilayer packages and PCBs
No full textWe introduce a model of simultaneous switching noise (SSN) coupling between the power/ground plane cavities through cutouts in high-speed and high-density multilayer packages and printed circuit boards (PCBs). Usually, the cutouts are used in multilayer plane structures to isolate the SSN of noisy digital circuits from sensitive analog circuits or to provide multiple voltage levels. The noise-coupling model is expressed in terms of the transfer impedance. The. proposed modeling and analysis results are compared with measured data up to 10 GHz to demonstrate the validity of the model. It is demonstrated that the cutout is the major gate for SSN coupling between the plane cavities, and that substantial SSN coupling occurs between the plane cavities through the cutout at the resonant frequencies of the plane cavities. We also analyze and discuss the coupling mechanism and characteristics of the noise coupling, from which we evaluate a method of suppression of the SSN coupling. Proper positioning of the cutout and the devices at each plane cavity achieves significant noise suppression at certain resonant frequencies. The suggested suppression method of the SSN coupling was successfully proved by frequency domain measurement and time domain analysis
Characterization of high-frequency plane-to-plane coupling through cutout in multi-layer packages
No full textObituary: Dr M.K. Bhan – A True Leader & Visionary
No full text12The author remembers Dr M.K. Bhan as a true leader, visionary, a passionate scientist, doctor and a wonderful human being, who has given love and affection to everyone around him
M.K. Asante: “It’s Bigger than Hip Hop: Art, Race and Politics”
No full textIncludes descriptive metadata provided by producer in MPEG-4 video file: "Arts and Culture - Video - M.K. Asante: 'It’s Bigger than Hip Hop: Art, Race and Politics.'" By M.K. Asante. Author and filmmaker Asante delivers the annual Walter R. Murray, Jr., Lecture on Oct. 20, 2010 at the Commons Center. He takes questions after his lecture
A Unified Shell model for Buoyancy-Driven Turbulence
No full textWe construct a unified shell model for stably stratified and convective turbulence. Shell model simulation of stably stratified flow in turbulent regime exhibit Bolgiano-Obukhbov (BO) scaling in which the kinetic energy spectrum varies as . However, simulation of convective turbulence shows Kolmogorov's spectrum. These results are consistent with the direct numerical simulations of Kumar {\em et al.} [Phys. Rev. E {\bf 90}, 023016 (2014)]. We also observe a dual scaling ( and ) for a limited range of parameters in stably stratified flow
Sweeping has no effect on renormalized turbulent viscosity
No full textWe perform renormalization group analysis (RG) of the Navier-Stokes equation in the presence of constant mean velocity field , and show that the renormalized viscosity is unaffected by , thus negating the ``sweeping effect", proposed by Kraichnan [Phys. Fluids {\bf 7}, 1723 (1964)] using random Galilean invariance. Using direct numerical simulation, we show that the correlation functions for and differ from each other, but the renormalized viscosity for the two cases are the same. Our numerical results are consistent with the RG calculations
Energy transfers in small-scale and large-scale dynamos
No full textWe study energy transfers during magnetic energy growth in small-scale and large-scale dynamos. We perform direct numerical simulations for magnetic Prandtl number Pm =20 and 0.2 in a periodic box on 1024^3 grid. Energy fluxes and shell-to-shell energy transfers indicate that in small-scale dynamo for Pm =20, the magnetic energy growth takes place due to a non-local energy transfer from large-scale velocity field to small-scale magnetic field. On the other hand, in large-scale dynamo for Pm =0.2, local energy transfers from large-scale velocity field to large-scale magnetic field takes place
- …
