In consideration of the contributions to this work, Feng Qian unequivocally requests the removal of his name from the author list of this publication [...]
The impact of key process parameters on the electrical characteristics of atomic layer deposited HfO2 films has been systematically studied with MHOS devices via capacitance–voltage (C–V) measurement. C–V hysteresis curves revealed that charge storage capacity is significantly enhanced with decreasing substrate temperature from 350 down to 150 °C and/or increasing purge time of the inert gas. The developed HfO2 trapping layer was also demonstrated by a MAHOS memory device. Improved memory window, fast program speed and good retention characteristics have been obtained. The study provides a reference for memory performance improvement of HfO2-based charge trap flash memory.
Virtual geographic environments (VGEs) are extensively used to explore the relationship between humans and environments. Crowd simulation provides a method for VGEs to represent crowd behaviors that are observed in the real world. The social force model (SFM) can simulate interactions among individuals, but it has not sufficiently accounted for inter-group and intra-group behaviors which are important components of crowd dynamics. We present the social group force model (SGFM), based on an extended SFM, to simulate group behaviors in VGEs with focuses on the avoiding behaviors among different social groups and the coordinate behaviors among subgroups that belong to one social group. In our model, psychological repulsions between social groups make them avoid with the whole group and group members can stick together as much as possible; while social groups are separated into several subgroups, the rear subgroups try to catch up and keep the whole group cohesive. We compare the simulation results of the SGFM with the extended SFM and the phenomena in videos. Then we discuss the function of Virtual Reality (VR) in crowd simulation visualization. The results indicate that the SGFM can enhance social group behaviors in crowd dynamics.
Here we report the formation of stimulus-responsive chemically end-grafted "brush-brushes" by synthesizing, mono thiol(end)-functionalized poly(methacrylic acid--ethylene glycol) or poly(MAA--EG) comb-type graft copolymers a combination of protecting group chemistry and atom transfer radical polymerization using the initiator 2-(2,4-dinitrophenylthio)ethyl 2-bromo-2-methyl propionate. The polymers were synthesized with three different molecular weights (15 k, 17 k and 27 k), PEG side chain graft densities (EG/MAA mole ratio = 2.2, 0.4 and 1.9, respectively), and a PEG molecular weight = 1100 and then chemically end-grafted to gold substrates chemisorption, resulting in molecular separation distances of ∼3-4 nm. pH-Dependent swelling was confirmed to take place gradually above pH 4-5 and quantified by heights measured by contact mode AFM imaging of microcontact printed (µCP) samples. Swelling factors (maximum height/minimum height) were fairly large (3.6-7.3) and a decrease in molecular weight by ∼2× and side chain graft density by ∼4× resulted in a decrease in swelling factor by ∼2×. Layer height normal force for all three polymers measured by contact mode atomic force microscope imaging on µCP samples at pH 9 showed a nonlinearly decreasing relationship and complete compression ∼<2 nm for forces >10 nN. At pH 4, all polymer layers were largely collapsed (heights ∼<4 nm) and incompressible (, heights were independent of normal force).
The impacts of natural processes and anthropogenic input on riverine nitrate (NO-3) could be identified by NO-3 concentrations and nitrogen and oxygen isotope ratios (δ15N-NO-3 and δ18O-NO-3); however, the effects of variable land use on riverine NO-3 sources and transformations remain unclear. In particular, the human impacts on riverine NO-3 in mountain areas are still unknown. The Yihe River and Luohe River were used to elucidate this question due to their spatially heterogeneous land use. Hydrochemical compositions, water isotope ratios (δD-H2O and δ18O-H2O), and δ15N-NO-3 and δ18O-NO-3 values were utilized to constrain the NO-3 sources and transformations affected by different land use types. The results indicated that ① the mean nitrate concentrations in the Yihe River and Luohe River waters were 6.57 and 9.29 mg·L-1, the mean values of δ15N-NO-3 were 9.6‰ and 10.4‰, and the average δ18O-NO-3 values were -2.2‰ and -2.7‰, respectively. Based on the analysis of δ15N-NO-3 and δ18O-NO-3 values, the NO-3 in the Yihe and Luohe Rivers were derived from multiple sources, and nitrogen removal existed in the Luohe River, but the biological removal in the Yihe River was weak. ② The contributions of different nitrate sources were calculated using a Bayesian isotope mixing model (BIMM) based on δ15N-NO-3 and δ18O-NO-3 values of river water in the mainstream and tributaries with spatial locations. The results revealed that sewage and manure had major impacts on riverine nitrate in the upper reaches of both the Luohe River and Yihe River, where forest vegetation was widely distributed. However, the contributions from soil organic nitrogen and chemical fertilizer were higher in the upper reaches than in downstream ones. The contributions of sewage and manure still increased in the downstream reaches. Our results confirmed the primary impacts of point sources, e.g., sewage and manure, on riverine nitrate in the studied area, and the contributions of nonpoint sources, e.g., chemical fertilizer, had not increased as the agricultural activities elevated the downstream. Therefore, more attention should be paid to point source pollution treatment, and the high-quality development of ecological civilization in the Yellow River Basin should be maintained.
Tyrosine kinase inhibitors (TKIs) have improved the overall survival of patients with gastrointestinal stromal tumors (GISTs), but their side effects can impact dose intensity and, consequently, the clinical benefit. To date, no guideline or consensus has been published on the TKI-associated adverse reactions. Therefore, the Chinese Society of Surgeons for Gastrointestinal Stromal Tumor of the Chinese Medical Doctor Association organized an expert panel discussion involving representatives from gastrointestinal surgery, medical oncology, cardiology, dermatology, nephrology, endocrinology, and ophthalmology to consider the systemic clinical symptoms, molecular and cellular mechanisms, and treatment recommendations of GISTs. Here, we present the resultant evidence- and experience-based consensus to guide the management of TKI-associated side events in clinical practice.
The production of structural and functional materials with enhanced mechanical properties through the integration of soft and hard components is a common approach to Nature's materials design. However, directly mimicking these optimized design routes in the lab for practical applications remains challenging. For example, graphene and silk are two materials with complementary mechanical properties that feature ultrahigh stiffness and toughness, respectively. Yet no simple and controllable approach has been developed to homogeneously integrate these two components into functional composites, mainly due to the hydrophobicity and chemical inertness of the graphene. In this study, well-dispersed and highly stable graphene/silk fibroin (SF) suspension systems were developed, which are suitable for processing to fabricate polymorphic materials, such as films, fibers, and coatings. The obtained graphene/SF nanocomposites maintain the electronic advantages of graphene, and they also allow tailorable mechanical performance to form including ultrahigh stretchable (with a strain to failure to 611±85%), or high strength (339 MPa) and high stiffness (7.4 GPa) material systems. More remarkably, the electrical resistances of these graphene/SF materials are sensitive to material deformation, body movement, as well as humidity and chemical environmental changes. These unique features promise their utility as wearable sensors, smart textiles, intelligent skins, and human-machine interfaces.
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