Two-dimensional (2-D) materials such as MoS
and phosphorene provide an ideal platform to realize extremely thin body metal-oxide-semiconductor field effect transistors (MOSFETs) which is highly ...immune to short channel effects in the ultra-scaled regime. Even with the excellent electrostatic integrity inherent in 2-D system, however, 2-D materials suffer from the lack of efficient doping method which is crucial in MOSFETs technology. Recently, an unusual phase transition from semiconductor to metal driven by the thickness modulation has been predicted in mono-elemental 2-D material arsenene. Utilizing this extraordinary property, we propose doping-free arsenene heterostructure MOSFETs based on the lateral multilayer (metallic source)/monolayer (semiconducting channel)/multilayer (metallic drain) arsenene heterostructure. Metallic multilayer arsenene in the source and drain can serve as electrodes without doping. We investigate the potential performance of arsenene heterostructure MOSFETs through atomistic simulations using density functional theory and nonequilibrium Green's function. The intrinsic upper limit of the on-state current in arsenene heterostructure MOSFETs is estimated by studying the effect of layer number in the source and drain. We comprehensively analyze the competitiveness of arsenene heterostructure MOSFETs through benchmarking with monolayer arsenene homostructure MOSFETs equipped with the highly degenerate doped source and drain, suggesting superior performance of heterostructure MOSFETs over homostructure MOSFETs.
Two-dimensional (2D) materials have been considered key materials for the future logic devices due to the excellent electrostatic integrity originating from their ultrathin nature. However, the ...carrier polarity control of 2D material field-effect transistors (FETs) still remains a challenging issue, hindering the realization of complementary logic function in the 2D material platform. Here, we report a comprehensive study on the electrical characteristics of PdSe2 FETs with different metal contacts. It is found that the carrier polarity in PdSe2 FETs can be modulated simply by changing the metal contact due to the weak Fermi-level pinning in PdSe2. We demonstrate a complementary metal-oxide-semiconductor (CMOS) inverter using the same channel material PdSe2 for n- and p-MOSFETs but with different metal contacts, suggesting the possible realization of PdSe2-based CMOS logic circuits.
The shoe upper hides the foot motion on the insole, so it has been challenging to measure the non-slip function of socks in a dynamic motor task. The study aimed to propose a method to estimate the ...non-slip function of socks in an acute maneuver. Participants performed a shuttle run task while wearing three types of socks with different frictional properties. The forces produced by foot movement on the upper during the task were measured by pressure sensors installed at the upper. A force platform was also used to measure the ground reaction force at the outsole and ground. Peak force and impulse values computed by using forces measured by the pressure sensors were significantly different between the sock conditions, while there were no such differences in those values computed by using ground reaction forces measured by a force platform. The results suggested that the non-slip function of socks could be quantified by measuring forces at the foot-upper interface. The method could be an affordable option to measure the non-slip function of socks with minimal effects from skin artifacts and shoe upper integrity.
This study aimed to demonstrate the effectiveness of urgent extracranial-to-intracranial bypass (EIB) in acute ischemic stroke (AIS) through quantitative analysis of computed tomography perfusion ...(CTP) results using RAPID software. We retrospectively analyzed 41 patients who underwent urgent EIB for AIS under strict operation criteria. The quantitative data from CTP images were reconstructed to analyze changes in pre- and postoperative perfusion status in terms of objective numerical values using RAPID software. Short- and long-term clinical outcomes, including complications and neurological status, were also analyzed. Postoperatively, the volume of time-to-max (Tmax) > 6 s decreased significantly; it continued to improve significantly until 6 months postoperatively (preoperative, 78 ml (median); immediate postoperative, 23 ml; postoperative 6 months, 7 ml; p = 0.000). Ischemic core-penumbra mismatch volumes were also significantly improved until 6 months postoperatively (preoperative, 72 ml (median); immediate postoperative, 23 ml; postoperative 6 months, 5 ml; p = 0.000). In addition, the patients' neurological condition improved significantly (p < 0.001). Only one patient (2.3%) showed progression of infarction. Urgent EIB using strict indications can be a feasible treatment for IAT-ineligible patients with AIS due to large vessel occlusion or stenosis.
The thickness‐modulated phase transition from semi‐metallic (bulk) to semiconductor (a few layers) is the most unique property of pentagonal palladium diselenide (PdSe2). Thus, precise thickness ...tailoring is essential to fully utilize its unique thickness‐dependent property for exotic device applications. Here, tunable current transport in PdSe2 based field‐effect transistors (FETs) enabled by layer‐by‐layer thinning of PdSe2 using mild SF6:N2 plasma is presented. With this top‐down plasma‐etching method, the PdSe2 layer thickness can be precisely modulated without structural degradation, which paves the way to realize the complete potential of PdSe2‐based devices. By modifying the plasma power and exposure time, an atomic layer precision etching rate of 0.4 nm min−1 can be achieved. Atomic‐force microscopy, Raman spectroscopy, and secondary ion mass spectrometry confirm the uniform and complete removal of top layers of PdSe2 flake over a large area without affecting remaining bottom layers. Electrical characterization of current transport in plasma‐thinned PdSe2 FETs reveals excellent layer‐dependent conductivity similar to pristine PdSe2 FETs. This simple but highly scalable and controllable plasma‐etching technique provides a promising way to fabricate PdSe2 devices based on lateral heterostructures composed of different thicknesses PdSe2 flakes to exploit strongly thickness‐dependent electronic structures.
A highly selective, reproducible, and CMOS compatible plasma‐etching technique for uniform layer‐by‐layer thinning of PdSe2 is demonstrated. The transport properties of plasma‐thinned PdSe2‐based devices exhibit well‐matched transport behavior compared to pristine PdSe2 FETs. This plasma‐thinning technique provides a promising way to fabricate PdSe2‐based devices utilizing strong thickness‐dependent electronic structures.
This study examines the moderating effect of social capital on the association between economic policy uncertainty (EPU) and cash holdings. Using a sample of US-listed firms from 1990 to 2018, social ...capital is found to have a positive moderating effect on the association between EPU and cash holdings. Our finding is robust even if we use alternative measures of cash, EPU, and social capital. Based on these outcomes, we suggest that firms located in a county with a high level of social capital endure high EPU by raising cash easily.
Nontraumatic subdural hematoma (SDH) is a common disease, and spinal cerebrospinal fluid (CSF) leakage is a possible etiology of unknown significance, which is commonly investigated by several ...invasive studies. This study demonstrates that heavily T2-weighted magnetic resonance myelography (HT2W-MRM) is a safe and clinically effective imaging modality for detecting CSF leakage in patients with nontraumatic SDH.
All patients who underwent HT2W-MRM for nontraumatic SDH workup at our institution were searched and enrolled in this study. Several parameters were measured and analyzed, including patient demographic data, initial modified Rankin Scale (mRS) score upon presentation, SDH bilaterality, hematoma thickness upon presentation, CSF leakage sites, treatment modalities, follow-up hematoma thickness, and follow-up mRS score.
Forty patients were identified, of which 22 (55.0%) had CSF leakage at various spinal locations. Five patients (12.5%) showed no change in mRS score, whereas the remaining (87.5%) showed decreases in follow-up mRS scores. In terms of the overall hematoma thickness, four patients (10.0%) showed increased thickness, two (5.0%) showed no change, 32 (80.0%) showed decreased thickness, and two (5.0%) did not undergo follow-up imaging for hematoma thickness measurement.
HT2W-MRM is not only safe but also clinically effective as a primary diagnostic imaging modality to investigate CSF leakage in patients with nontraumatic SDH. Moreover, this study suggests that CSF leakage is a common etiology for nontraumatic SDH, which warrants changes in the diagnosis and treatment strategies.
For this study, we designed an implantable rectangular spiral antenna for medical biotelemetry in the Medical Implant Communications Service band (402 MHz to 405 MHz). The designed antenna has a ...U‐shaped loop for impedance matching. The antenna impedance is easily adjusted by controlling the shape and length of the U‐shaped loop. Significant design parameters were studied to understand their effects on the antenna performance. To verify the potential of the antenna for the desired applications, we fabricated a prototype and measured its performance in terms of the resonant characteristics and gain radiation patterns of the antenna. In the testing phase, the prototype antenna was embedded in human skin tissue–emulating gel, which was developed to simulate a real operation environment. The measured resonant characteristics show good agreement with the simulations, and the −10 dB frequency band is within the range of 398 MHz to 420 MHz. The antenna exhibits a maximum gain of −22.26 dBi and an antenna efficiency of 0.215%.
OBJECTIVETo analyze the angiographic features and clinical course, including treatment outcomes and the natural course, of fusiform middle cerebral artery aneurysms (FMCAAs) according to their ...location, size, and configuration. METHODSWe reviewed the literature on adult cases of FMCAAs published from 1980 to 2018; from 25 papers, 112 FMCAA cases, for which the location, size, and configuration could be identified, were included in this study. Additionally, 33 FMCAA cases in our hospital were included, from which 16 were assigned to the observation group. Thus, a total of 145 adult FMCAA cases were included. We classified the FMCAAs according to their location (l-type 1, beginning from prebifurcation; l-type 2, beginning from bifurcation; l-type 3, beginning from postbifurcation), size (small, <10 mm; large, ≥10 mm; giant, ≥25 mm), and configuration (c-type 1, classic dissecting aneurysm; c-type 2, segmental ectasia; c-type 3, dolichoectatic dissecting aneurysm). RESULTSThe c-type 3 was more commonly diagnosed with ischemic symptoms (31.8%) than hemorrhage (13.6%), while 40.9% were found accidentally. In contrast, c-type 2 was more commonly diagnosed with hemorrhagic symptoms (14.9%) than ischemic symptoms (10.6%), and 72.3% were accidentally discovered. According to location, ischemic symptoms and hemorrhage were the most frequent symptoms in l-type 1 (28.6%) and l-type 3 (34.6%), respectively. Most of l-type 2 FMCAAs were found incidentally (68.4%). Based on the size of FMCAAs, only 11.1% of small aneurysms were found to be hemorrhagic, while 18.9% and 26.0% of large and giant aneurysms were hemorrhagic, respectively. Although four aneurysms of the 16 FMCAAs in the observation group increased in size and one aneurysm decreased in size during the observation period, no rupture was seen in any case and there were no significant predictors of aneurysm enlargement. Of 104 FMCAAs treated, 14 cases (13.5%) were aggravated than before surgery and all the aggravated cases were l-type 1. CONCLUSIONWhile ischemic symptoms occurred more frequently in l-type 1 and c-type 3, hemorrhagic rather than ischemic symptoms occurred more frequently in l-type 3 and c-type 2. In case of l-type 1 FMCAAs, more caution is required in determining the treatment due to the relatively high complication rate.
This study examines the effect of CEOs' educational background on the cash holdings policy and value of excess cash in Korean firms considering the education system in Korea, where academic tracks ...are determined earlier in life than in other countries. We show that although firms with CEOs who majored in business or in science or engineering have less cash holdings, the value of excess cash holdings varies by major. We find that firms with CEOs who majored in business (science or engineering) show a higher (lower) value of excess cash than other CEOs. Moreover, firms whose CEOs have a master's degree show a higher value of excess cash. In sum, this study suggests that corporate financial policy depends on CEOs' educational background, which determines their personal traits and professional career experience and thus lead to different firm performance in terms of cash holdings policy and the value of excess cash.
•This paper studies academic background effect of CEO in Korea.•Firms with CEOs who majored in business are likely to have less cash.•Firms with CEOs who majored in business also show higher value of excess cash.•The Governance effect on cash holdings varies by CEO's academic background.•Our study suggests the corporate cash policy depends on CEO's academic background.
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