INVESTIGATION OF INTERFACES IN ORGANIC FIELD-EFFECT TRANSISTORS

Ph.DDOCTOR OF PHILOSOPH

Head-raising of snake robots based on a predefined spiral curve method

© 2018 by the authors. A snake robot has to raise its head to acquire a wide visual space for planning complex tasks such as inspecting unknown environments, tracking a flying object and acting as a manipulator with its raising part. However, only a few researchers currently focus on analyzing the head-raising motion of snake robots. Thus, a predefined spiral curve method is proposed for the head-raising motion of such robots. First, the expression of the predefined spiral curve is designed. Second, with the curve and a line segments model of a snake robot, a shape-fitting algorithm is developed for constraining the robot's macro shape. Third, the coordinate system of the line segments model of the robot is established. Then, phase-shifting and angle-solving algorithms are developed to obtain the angle sequences of roll, pitch, and yaw during the head-raising motion. Finally, the head-raising motion is simulated using the angle sequences to validate the feasibility of this method

Physical human-robot collaboration: Robotic systems, learning methods, collaborative strategies, sensors, and actuators

This article presents a state-of-the-art survey on the robotic systems, sensors, actuators, and collaborative strategies for physical human-robot collaboration (pHRC). This article starts with an overview of some robotic systems with cutting-edge technologies (sensors and actuators) suitable for pHRC operations and the intelligent assist devices employed in pHRC. Sensors being among the essential components to establish communication between a human and a robotic system are surveyed. The sensor supplies the signal needed to drive the robotic actuators. The survey reveals that the design of new generation collaborative robots and other intelligent robotic systems has paved the way for sophisticated learning techniques and control algorithms to be deployed in pHRC. Furthermore, it revealed the relevant components needed to be considered for effective pHRC to be accomplished. Finally, a discussion of the major advances is made, some research directions, and future challenges are presented

Analytical Study on the Tidal Wave Propagation Coupled with Vertical Leakage from a Vertically Heterogeneous Aquitard in a Coastal Leaky Aquifer System

AbstractAnalytical studies on the tidal wave propagation in a coastal leaky aquifer commonly assume that the low-permeability aquitard is homogeneous. The aquitard is, however, vertically heterogeneous in nature due to varying soil types along the burial depth as can be frequently seen from borehole logs. In this study, an innovative analytical model is developed to explore the vertical heterogeneity in aquitard hydraulic conductivity (K) and specific storage (Ss) on the tidal wave propagation coupling with vertical leakage from the aquitard. The novelty behind the newly derived analytical solution is attributed to the fact that the aquitard along the burial depth can be divided into any number of homogeneous zones, each of which is associated with distinct K and Ss values, so that arbitrary vertical heterogeneity pattern of aquitard K and Ss can be captured. Theoretical analysis results reveal that an interlayer within the aquitard with a smaller K can significantly enhance the amplitude and phase shift of periodic groundwater head fluctuations in the leaky aquifer, while a larger Ss of the interlayer will weaken the amplitude and phase shift provided a relatively small aquitard K. Buried locations of the interlayer also implement nonnegligible effects on the tidal wave propagation. For the scenario of exponentially decaying aquitard K and Ss, which is commonly encountered for a thick aquitard, a larger decay exponent results in smaller amplitude and phase shift. This analytical study highlights the importance of vertical aquitard heterogeneity on tidal wave propagation in a coastal leaky aquifer system

Impacts of groundwater depth on regional scale soil gleyization under changing climate in the Poyang Lake Basin, China

This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ which permits use, distribution and reproduction in any medium, provided the original work is properly cited. This author accepted manuscript is made available following 24 month embargo from date of publication (November 2018) in accordance with the publisher’s archiving policyVarious natural and anthropogenic factors affect the formation of gleyed soil. It is a major challenge to identify the key hazard factors and evaluate the dynamic evolutionary process of soil gleyization at a regional scale under future climate change. This study addressed this complex challenge based on regional groundwater modelling for a typical agriculture region located in the Ganjiang River Delta (GRD) of Poyang Lake Basin, China. We first implemented in-situ soil sampling analysis and column experiments under different water depths to examine the statistical relationship between groundwater depth (GD) and gleyization indexes including active reducing substance, ferrous iron content, and redox potential. Subsequently, a three-dimensional groundwater flow numerical model for the GRD was established to evaluate the impacts of the historical average level and future climate change on vadose saturation and soil gleyization (averaged over 2016–2050) in the irrigated farmland. Three climate change scenarios associated with carbon dioxide emission (A1B, A2, and B1) were predicted by the ECHAM5 global circulation model published in IPCC Assessment Report (2007). The ECHAM5 outputs were applied to quantify the variation of groundwater level and to identify the potential maximum gleyed zones affected by the changes of meteorological and hydrological conditions. The results of this study indicate that GD is an indirect indicator for predicting the gradation of soil gleyization at the regional scale, and that the GRD will suffer considerable soil gleyization by 2050 due to fluctuations of the water table induced by future climate changes. Compared with the annually average condition, the climate scenario B1 will probably exacerbate soil gleyization with an 8.8% increase in total gleyed area in GRD. On average, the highly gleyed areas will increase in area by 29.7 km2, mainly on the riverside area, and the medium-slightly gleyed area will increase by 19.2 km2 in the middle region.This work was partially supported by the National Key R&D Program of China (No. 2016YFC0402800), the National Natural Science Foundation of China (Nos. 41772254, 41502226, and 41402198), and the Fundamental Research Funds for the Central Universities (No. 2018B18714). We are grateful to Jiangxi Institute of Survey and Design, who provides the detailed hydrogeological data of PLB for establishing three-dimensional groundwater flow model. Yun Yang gratefully acknowledges financial support from China Scholarship Council (CSC No. 201706715023) during the visit to National Centre for Groundwater Research and Training (NCGRT), Australia. Behzad Ataie-Ashtiani and Craig T. Simmons acknowledge support from the National Centre for Groundwater Research and Training, Australia

Dual Antiplatelet Treatment up to 72 Hours after Ischemic Stroke

BackgroundDual antiplatelet treatment has been shown to reduce recurrence of stroke compared to aspirin alone when initiated early after an acute stroke. The effect of clopidogrel and aspirin versus aspirin alone within 72 hours of acute cerebral ischemia from atherosclerosis has not been well studied.MethodsWe conducted a randomized, double-blind, placebo-controlled, 2-by-2 factorial trial in patients with mild ischemic stroke or high-risk transient ischemic attack (TIA) of presumed atherosclerotic cause, not receiving thrombolysis or thrombectomy in 222 hospitals in China. Patients were randomly assigned within 72 hours after symptom onset in a 1:1 ratio, to receive clopidogrel (300mg on day 1, 75mg daily on days 2-90) and aspirin (100-300mg on day1, 100mg daily on days 2-21), or clopidogrel placebo and aspirin (100-300mg on day1, 100mg daily on days 2-90). There was no interaction between this component of the factorial trial design trial and a second part that tested immediate vs delayed stain treatment and is reported separately. The primary efficacy outcome was a new stroke, and the primary safety outcome was moderate-to-severe bleeding, both within 90 days.ResultsA total of 6100 patients were enrolled, 3050 assigned to each trial group. The qualifying event for enrollment was TIA in 13%. Approximately 13% of patients were assigned to a treatment group within 24 hours and 87% were assigned between 24 and 72 hours of onset of stroke. A new stroke occurred in 222 (7.3%) in the clopidogrel-aspirin group, and 279 (9.2%) in the aspirin group (hazard ratio, 0.79; 95% confidence interval [CI], 0.66-0.94; P=0.008). Moderate-to-severe bleeding occurred in 27 (0.9%) and 13 patients (0.4%), respectively (hazard ratio, 2.08; 95% CI, 1.07-4.04, P=0.03).ConclusionsAmong patients with mild ischemic stroke or high-risk TIA of presumed atherosclerotic cause, combined clopidogrel-aspirin initiated within 72 hours of onset was superior to aspirin alone in reducing the risk of new stroke at 90 days but was associated with a low but increased risk of moderate-to-severe bleeding

2021 Taxonomic update of phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales.

Correction to: 2021 Taxonomic update of phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales. Archives of Virology (2021) 166:3567–3579. https://doi.org/10.1007/s00705-021-05266-wIn March 2021, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by four families (Aliusviridae, Crepuscuviridae, Myriaviridae, and Natareviridae), three subfamilies (Alpharhabdovirinae, Betarhabdovirinae, and Gammarhabdovirinae), 42 genera, and 200 species. Thirty-nine species were renamed and/or moved and seven species were abolished. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.This work was supported in part through Laulima Government Solutions, LLC prime contract with the US National Institute of Allergy and Infectious Diseases (NIAID) under Contract No. HHSN272201800013C. J.H.K. performed this work as an employee of Tunnell Government Services (TGS), a subcontractor of Laulima Government Solutions, LLC under Contract No. HHSN272201800013C. This work was also supported in part with federal funds from the National Cancer Institute (NCI), National Institutes of Health (NIH), under Contract No. 75N91019D00024, Task Order No. 75N91019F00130 to I.C., who was supported by the Clinical Monitoring Research Program Directorate, Frederick National Lab for Cancer Research. This work was also funded in part by Contract No. HSHQDC-15-C-00064 awarded by DHS S&T for the management and operation of The National Biodefense Analysis and Countermeasures Center, a federally funded research and development center operated by the Battelle National Biodefense Institute (V.W.); and NIH contract HHSN272201000040I/HHSN27200004/D04 and grant R24AI120942 (N.V., R.B.T.). S.S. acknowledges partial support from the Special Research Initiative of Mississippi Agricultural and Forestry Experiment Station (MAFES), Mississippi State University, and the National Institute of Food and Agriculture, US Department of Agriculture, Hatch Project 1021494. Part of this work was supported by the Francis Crick Institute which receives its core funding from Cancer Research UK (FC001030), the UK Medical Research Council (FC001030), and the Wellcome Trust (FC001030).S

Space advanced technology demonstration satellite

The Space Advanced Technology demonstration satellite (SATech-01), a mission for low-cost space science and new technology experiments, organized by Chinese Academy of Sciences (CAS), was successfully launched into a Sun-synchronous orbit at an altitude of similar to 500 km on July 27, 2022, from the Jiuquan Satellite Launch Centre. Serving as an experimental platform for space science exploration and the demonstration of advanced common technologies in orbit, SATech-01 is equipped with 16 experimental payloads, including the solar upper transition region imager (SUTRI), the lobster eye imager for astronomy (LEIA), the high energy burst searcher (HEBS), and a High Precision Magnetic Field Measurement System based on a CPT Magnetometer (CPT). It also incorporates an imager with freeform optics, an integrated thermal imaging sensor, and a multi-functional integrated imager, etc. This paper provides an overview of SATech-01, including a technical description of the satellite and its scientific payloads, along with their on-orbit performance