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Inre antenn knappast en enkel match

Mobiltelefonen har gått igenom en enorm teknisk utveckling de senaste åren. För antennens del har det inneburit en rad förändringar och denna artikel försöker beskriva några av de nya utmaningar som antennspecialisterna idag ställs inför. Antennen är numera ofta inbyggd i telefonen och täcker fler band på högre frekvenser och som inbyggd har den betydligt sämre förutsättningar än tidigare att fung

Analysis of Fluid Flow and Heat Transfer for Proton Exchange Membrane Fuel Cells by an Extended Darcy Model

By using a three dimensional computational method, gas flow and heat transfer have been investigated and analyzed for both cathode / anode ducts of proton exchange membrane fuel cells. The Brinkman- Forchheimer-extended Darcy model is employed to investigate the flow inside the porous layer of the duct. Effects of inertial coefficient, together with permeability, effective thermal conductivity, th

Phase noise reduction in RF CMOS VCO's via capacitive filtering

This paper presents the experimental results of two different techniques, the already known inductive degeneration technique and the new capacitive filtering technique, for reducing the phase noise in RF CMOS VCO's. The techniques are applied to two distinct VCO designs, showing that the largest phase noise reduction (up to 7 dB at 3 MHz offset frequency from the carrier) is achieved via inductive

Reconstruction of nonlinear material properties for homogeneous, isotropic slabs using electromagnetic waves

This paper addresses the inverse problem of reconstructing a medium’s instantaneous, nonlinear response to electromagnetic excitation. Using reflection and transmission data for an almost arbitrary incident field on a homogeneous slab, we are able to obtain the nonlinear constitutive relations for both electric and magnetic fields, with virtually no assumptions made on the specific form of the rel

Regional cerebral blood flow in schizophrenia: repeated studies during a psychotic episode

Regional cerebral blood flow (rCBF) measurements and clinical ratings were performed on 17 schizophrenic patients and a subgroup of 10 medication-free patients before and after treatment. While clinically exacerbated patients had normal blood flow, patients in remission showed a redistribution of flow with lower values in frontal areas. Anteroposterior ratios correlated with the degree of behavior

Closer to a win-win situation? Changes in the salespersons-customer relationship when implementing value-selling

Value selling is often presented to be the most profitable and competitive sales practice in business markets. This paper argues that the relevant theory does not consider the consequences of introducing value selling for the relationship between the individual salesperson and buyer. This is problematic since the literature assigns most responsibilities within value selling to the salesperson. The