Fabrication of integrated planar gunn diode and micro-cooler on GaAs substrate

We demonstrate fabrication of an integrated micro cooler with the planar Gunn diode and characterise its performance. First experimental results have shown a small cooling at the surface of the micro cooler. This is first demonstration of an integrated micro-cooler with a planar Gunn diode

Micro-cooler Enhancements by Barrier Interface Analysis

Peer reviewedPublisher PD

Impact ionisation electroluminescence in planar GaAs-based heterostructure Gunn diodes:Spatial distribution and impact of doping nonuniformities

When biased in the negative differential resistance regime, electroluminescence (EL) is emitted from planar GaAs heterostructure Gunn diodes. This EL is due to the recombination of electrons in the device channel with holes that are generated by impact ionisation when the Gunn domains reach the anode edge. The EL forms non-uniform patterns whose intensity shows short-range intensity variations in the direction parallel to the contacts and decreases along the device channel towards the cathode. This paper employs Monte Carlo models, in conjunction with the experimental data, to analyse these non-uniform EL patterns and to study the carrier dynamics responsible for them. It is found that the short-range lateral (i.e., parallel to the device contacts) EL patterns are probably due to non-uniformities in the doping of the anode contact, illustrating the usefulness of EL analysis on the detection of such inhomogeneities. The overall decreasing EL intensity towards the anode is also discussed in terms of the interaction of holes with the time-dependent electric field due to the transit of the Gunn domains. Due to their lower relative mobility and the low electric field outside of the Gunn domain, freshly generated holes remain close to the anode until the arrival of a new domain accelerates them towards the cathode. When the average over the transit of several Gunn domains is considered, this results in a higher hole density, and hence a higher EL intensity, next to the anode

Measuring the Reflection Matrix of a Rough Surface

Phase modulation methods for imaging around corners with reflectively scattered light required illumination of the occluded scene with a light source either in the scene or with direct line of sight to the scene. The RM (reflection matrix) allows control and refocusing of light after reflection, which could provide a means of illuminating an occluded scene without access or line of sight. Two optical arrangements, one focal-plane, the other an imaging system, were used to measure the RM of five different rough-surface reflectors. Intensity enhancement values of up to 24 were achieved. Surface roughness, correlation length, and slope were examined for their effect on enhancement. Diffraction-based simulations were used to corroborate experimental results

Sex differences in treatment and outcomes of patients with in-hospital ST-elevation myocardial infarction.

BACKGROUND AND HYPOTHESIS Two cohorts face high mortality after ST-elevation myocardial infarction (STEMI): females and patients with in-hospital STEMI. The aim of this study was to evaluate sex differences in ischemic times and outcomes of in-hospital STEMI patients. METHODS Consecutive STEMI patients treated with percutaneous coronary intervention (PCI) were prospectively recruited from 30 hospitals into the Victorian Cardiac Outcomes Registry (2013-2018). Sex discrepancies within in-hospital STEMIs were compared with out-of-hospital STEMIs. The primary endpoint was 12-month all-cause mortality. Secondary endpoints included symptom-to-device (STD) time and 30-day major adverse cardiovascular events (MACE). To investigate the relationship between sex and 12-month mortality for in-hospital versus out-of-hospital STEMIs, an interaction analysis was included in the multivariable models. RESULTS A total of 7493 STEMI patients underwent PCI of which 494 (6.6%) occurred in-hospital. In-hospital versus out-of-hospital STEMIs comprised 31.9% and 19.9% females, respectively. Female in-hospital STEMIs were older (69.5 vs. 65.9 years, p = .003) with longer adjusted geometric mean STD times (104.6 vs. 94.3 min, p < .001) than men. Female versus male in-hospital STEMIs had no difference in 12-month mortality (27.1% vs. 20.3%, p = .92) and MACE (22.8% vs. 19.3%, p = .87). Female sex was not independently associated with 12-month mortality for in-hospital STEMIs which was consistent across the STEMI cohort (OR: 1.26, 95% CI: 0.94-1.70, p = .13). CONCLUSIONS In-hospital STEMIs are more frequent in females relative to out-of-hospital STEMIs. Despite already being under medical care, females with in-hospital STEMIs experienced a 10-min mean excess in STD time compared with males, after adjustment for confounders. Adjusted 12-month mortality and MACE were similar to males

Differences in outcomes of patients with in-hospital versus out-of-hospital ST-elevation myocardial infarction: a registry analysis

OBJECTIVES Patients with ST-elevation myocardial infarction (STEMI) that occur while already in hospital ('in-hospital STEMI') face high mortality. However, data about this patient population are scarce. We sought to investigate differences in reperfusion and outcomes of in-hospital versus out-of-hospital STEMI. DESIGN, SETTING AND PARTICIPANTS Consecutive patients with STEMI all treated with percutaneous coronary intervention (PCI) across 30 centres were prospectively recruited into the Victorian Cardiac Outcomes Registry (2013-2018). PRIMARY AND SECONDARY OUTCOMES Patients with in-hospital STEMI were compared with patients with out-of-hospital STEMI with a primary endpoint of 30-day major adverse cardiovascular events (MACE). Secondary endpoints included ischaemic times, all-cause mortality and major bleeding. RESULTS Of 7493 patients with PCI-treated STEMI, 494 (6.6%) occurred in-hospital. Patients with in-hospital STEMI were older (67.1 vs 62.4 years, p<0.001), more often women (32% vs 19.9%, p<0.001), with more comorbidities. Patients with in-hospital STEMI had higher 30-day MACE (20.4% vs 9.8%, p<0.001), mortality (12.1% vs 6.9%, p<0.001) and major bleeding (4.9% vs 2.3%, p<0.001), than patients with out-of-hospital STEMI. According to guideline criteria, patients with in-hospital STEMI achieved symptom-to-device times of ≤70 min and ≤90 min in 29% and 47%, respectively. Patients with out-of-hospital STEMI achieved door-to-device times of ≤90 min in 71%. Occurrence of STEMI while in hospital independently predicted higher MACE (adjusted OR 1.77, 95% CI 1.33 to 2.36, p<0.001) and 12-month mortality (adjusted OR 1.49, 95% CI 1.08 to 2.07, p<0.001). CONCLUSIONS Patients with in-hospital STEMI experience delays to reperfusion with significantly higher MACE and mortality, compared with patients with out-of-hospital STEMI, after adjustment for confounders. Focused strategies are needed to improve recognition and outcomes in this high-risk and understudied population