Normal Pressure Hydrocephalus as an Unusual Presentation of Supratentorial Extraventricular Space-Occupying Processes: Report on Two Cases

Normal pressure hydrocephalus (NPH) is a clinical and radiographic syndrome characterized by ventriculomegaly, abnormal gait, urinary incontinence, and dementia. The condition may occur due to a variety of secondary causes but may be idiopathic in approximately 50% of patients. Secondary causes may include head injury, subarachnoid hemorrhage, meningitis, and central nervous system tumor. Here, we describe two extremely rare cases of supratentorial extraventricular space-occupying processes: meningioma and glioblastoma multiforme, which initially presented with NPH

Operation and performance of the 4H-SiC junctionless FinFET

Abstract: This work presents a comprehensive study on the behaviour and operation of a vertical 1.2 kV 4H-SiC junctionless power FinFET. The increased bulk conduction in the channel of this topology may bring reductions in the channel resistance compared to trench MOSFETs, whose performance is limited by the high interface state density. For this purpose, finite element (FE) simulations are used to examine the operation of this device. It is hence demonstrated that the junctionless FinFET can attain a high average channel drift mobility well above 100 cm2/(Vs), leaving the resistance to be determined by the drift and substrate regions. This allows the FinFET to turn on and reach its steady state current using a much (> 3x) smaller gate overdrive than standard designs. On the other hand, however, the overly high field in the gate oxide, the lack of an efficient mechanism for hole extraction, and the low threshold voltage can cause significant reliability issues. Furthermore, it is shown that the high input capacitance of the FinFET can limit its switching speed to slower levels than in standard trench MOSFETs, which raises the need for further development of the original design proposed for vertical GaN devices. In this context, it is demonstrated that the addition of a p-shield below the trenches can alleviate the off-state reliability issues and increase the speed, while still maintaining a competitive R on ∼ 2mΩ cm2 even without the use of n-JFET enhancement doping

Interdependence of photon upconversion performance and antisolvent processing in thin film halide perovskite sensitized triplet triplet annihilators

We prepared triplet triplet annihilation photon upconverters combining thin film methylammonium lead iodide MAPI perovskite with a rubrene annihilator in a bilayer structure. Excitation of the perovskite film leads to delayed, upconverted photoluminescence emitted from the annihilator layer, with triplet excitation of the rubrene being driven by carriers excited in the perovskite layer. To better understand the connections between the semiconductor properties of the perovskite film and the upconversion efficiency, we deliberately varied the perovskite film properties by modifying two spin coating conditions, namely, the choice of antisolvent and the antisolvent dripping time, and then studied the resulting photon upconversion performance with a standard annihilator layer. A stronger upconversion effect was exhibited when the perovskite films displayed brighter and more uniform photoluminescence. Both properties were sensitive to the antisolvent dripping time and were maximized for a dripping time of 20 s measured relative to the end of the spin coating program . Surprisingly, the choice of antisolvent had a significant effect on the upconversion performance, with anisole treated films yielding on average a tenfold increase in upconversion intensity compared to the chlorobenzene treated equivalent. This performance difference was correlated with the carrier lifetime in the perovskite film, which was 52 ns and 306 ns in the brightest chlorobenzene and anisole treated films, respectively. Since the bulk properties of the anisole and chlorobenzene treated films were virtually identical, we concluded that differences in the defect density at the MAPI rubrene interface, linked to the choice of antisolvent, must be responsible for the differing upconversion performanc