Understanding effective lifetimes measured on oxidized silicon wafers with different techniques

The interpretation of minority carrier Iifetime measurements on oxidized wafers is often difficult. Nonlinear decays in transient measurements or apparently incompatible results from different measurement techniques are observed. We present a comparison of measured results from three different techniques: photoconductance decay PCD, modulated free carrier absorption MFCA and lateral photocurrent LPC. An extended SRH formalism for the Si/SiO2, interface is used for modelling the experimental findings. With correct accounting for injection level dependent surface recombination an excellent agreement between the different methods is obtained on the basis of oxide parameters measured with MOS-techniques

An Electrostatic Free-Electron Maser for Fusion - Design Considerations

For the next generation of large tokamaks, efficient mm-wave sources at frequencies of up to 300 GHz and unit size of 1 MW cw will be required. The design of a free electron maser for this application, based on a dc electrostatic accelerator, is discussed

The design of an ECRH system for JET-EP

An electron cyclotron resonance heating (ECRH) system has been designed for JET in the framework of the JET enhanced performance project (JET-EP) under the European fusion development agreement. Due to financial constraints it has been decided not to implement this project. Nevertheless, the design work conducted from April 2000 to January 2002 shows a number of features that can be relevant in preparation of future ECRH systems, e.g. for ITER. The ECRH system was foreseen to comprise six gyrotrons, 1 MW each, in order to deliver 5 MW into the plasma (Verhoeven A.G.A. et al 2001 The ECRH system for JET 26th Int. Conf. on Infrared and Millimeter Waves (Toulouse, 10–14 September 2001) p 83; Verhoeven A.G.A. et al 2003 The 113 GHz ECRH system for JET Proc. 12th Joint Workshop on ECE and ECRH (13–16 May 2002) ed G. Giruzzi (Aix-en-Provence: World Scientific) pp 511–16). The main aim was to enable the control of neo-classical tearing modes. The paper will concentrate on: the power-supply and modulation system, including series IGBT switches, to enable independent control of each gyrotron and an all-solid-state body power supply to stabilize the gyrotron output power and to enable fast modulations up to 10 kHz and a plug-in launcher that is steerable in both toroidal and poloidal angles and able to handle eight separate mm-wave beams. Four steerable launching mirrors were foreseen to handle two mm-wave beams each. Water cooling of all the mirrors was a particularly ITER-relevant feature

Altered exhaled biomarker profiles in children during and after rhinovirus-induced wheeze

Preschool rhinovirus-induced wheeze is associated with an increased risk of asthma. In adult asthma, exhaled volatile organic compounds (VOC) are associated with inflammatory activity. We therefore hypothesised that acute preschool wheeze is accompanied by a differential profile of exhaled VOC, which is maintained after resolution of symptoms in those children with rhinovirus-induced wheeze. We included 178 children (mean +/- SD age 22 +/- 9 months) from the EUROPA cohort comparing asymptomatic and wheezing children during respiratory symptoms and after recovery. Naso- and oropharyngeal swabs were tested for rhinovirus by quantitative PCR. Breath was collected via a spacer and analysed using an electronic nose. Between-group discrimination was assessed by constructing a 1000-fold cross-validated receiver operating characteristic curve. Analyses were stratified by rhinovirus presence/absence. Wheezing children demonstrated a different VOC profile when compared with asymptomatic children (p <0.001), regardless of the presence (area under the curve (AUC) 0.77, 95% CI 0.07) or absence (AUC 0.81, 95% CI 0.05) of rhinovirus. After symptomatic recovery, discriminative accuracy was maintained in children with rhinovirus-induced wheeze (AUC 0.84, 95% CI 0.06), whereas it dropped significantly in infants with non-rhinovirus-induced wheeze (AUC 0.67, 95% CI 0.06). Exhaled molecular profiles differ between preschool children with and without acute respiratory wheeze. This appears to be sustained in children with rhinovirus-induced wheeze after resolution of symptoms. Therefore, exhaled VOC may qualify as candidate biomarkers for early signs of asthm

The design of an ECRH system for JET-EP

An electron cyclotron resonance heating (ECRH) system has been designed for JET in the framework of the JET enhanced performance project (JET-EP) under the European fusion development agreement. Due to financial constraints it has been decided not to implement this project. Nevertheless, the design work conducted from April 2000 to January 2002 shows a number of features that can be relevant in preparation of future ECRH systems, e.g. for ITER. The ECRH system was foreseen to comprise six gyrotrons, 1 MW each, in order to deliver 5 MW into the plasma (Verhoeven A.G.A. et al 2001 The ECRH system for JET 26th Int. Conf on Infrared and Millimeter Waves (Toulouse, 10-14 September 2001) p 83; Verhoeven A.G.A. et al 2003 The 113 GHz ECRH system for JET Proc. 12th Joint Workshop on ECE and ECRH (13-16 May 2002) ed G. Giruzzi (Aix-en-Provence: World Scientific) pp 511-16). The main aim was to enable the control of neo-classical tearing modes. The paper will concentrate on: the power-supply and modulation system, including series IGBT switches, to enable independent control of each gyrotron and an all-solid-state body power supply to stabilize the gyrotron output power and to enable fast modulations up to 10 kHz and a plug-in launcher that is steerable in both toroidal and poloidal angles and able to handle eight separate mm-wave beams. Four steerable launching mirrors were foreseen to handle two mm-wave beams each. Water cooling of all the mirrors was a particularly ITER-relevant feature