The safety issue of lithium‐ion batteries is a crucial factor limiting their large‐scale application. Therefore, it is of practical significance to evaluate the impact of their overcharge behavior ...because of the severe levels of oxygen release of cathode materials during this process. Herein, by combining a variety of in situ techniques of spectroscopy and electron microscopy, this work studies the structural degradation of LiNi0.8Co0.1Mn0.1O2 (NCM811) accompanying the oxygen release in the overcharge process. It is observed that a small amount of O2 evolves from the initial surface at ≈4.7 V. When charging to a higher voltage (≈5.5 V), a large amount of O2 evolves on the newly formed surface due to the occurrence of microcracks. Based on experimental results and theoretical calculations, it is determined that the oxygen release mainly occurs in the near‐surface regions, where the remaining oxygen vacancies accumulate to create voids. To suppress the oxygen release, single‐crystalline NCM811 with integrated structure is introduced and serves as a cathode, which can effectively inhibit morphology destruction and reduce the activation of lattice oxygen in the surface region. These findings provide a theoretical basis and effective strategy for improving the safety performance of Ni‐rich cathode materials in practical applications.
Safety issues hinder the commercialization of Ni‐rich cathode materials. Oxygen release occurs from different regions during the overcharge process as shown by several in situ spectroscopy techniques and electron microscopy. O2 appears first in the near‐surface region of secondary particles, then on the fresh surface between primary particles due to the occurrence of microcracks. Single‐crystalline NCM811 with integrated structure could reduce this phenomenon.
Physical Properties of 5 Root Canal Sealers Zhou, Hui-min, PhD; Shen, Ya, DDS, PhD; Zheng, Wei, PhD ...
Journal of endodontics,
10/2013, Letnik:
39, Številka:
10
Journal Article
Recenzirano
Abstract Introduction The aim of this study was to evaluate the pH change, viscosity and other physical properties of 2 novel root canal sealers (MTA Fillapex and Endosequence BC) in comparison with ...2 epoxy resin-based sealers (AH Plus and ThermaSeal), a silicone-based sealer (GuttaFlow), and a zinc oxide-eugenol–based sealer (Pulp Canal Sealer). Methods ISO 6876/2001 specifications were followed. The pH change of freshly mixed and set sealers was evaluated during periods of 1 day and 5 weeks, respectively. The viscosity was investigated at different injection rates (72, 10, and 5 mm/min) at room temperature by using a syringe-based system that was based on the Instron 3360 series universal testing system. Results The flow, dimensional change, solubility, and film thickness of all the tested sealers were in agreement with ISO 6876/2001 recommendations. The MTA Fillapex sealer exhibited a higher flow than the Endosequence BC sealer ( P < .05). The MTA Fillapex and Endosequence BC sealers showed the highest film thicknesses among the tested samples. The Endosequence BC sealer exhibited the highest value of solubility, which was in accordance with 3% mass fraction recommended by the ISO 6876/2001, and showed an acceptable dimensional change. The MTA Fillapex and Endosequence BC sealers presented an alkaline pH at all times. The pH of fresh samples of the AH Plus and ThermaSeal sealers was alkaline at first but decreased significantly after 24 hours. The viscosity of the tested sealers increased with the decreased injection rates. Conclusions The tested sealers were pseudoplastic according to their viscosities as determined in this study. The MTA Fillapex and Endosequence BC sealers each possessed comparable flow and dimensional stability but higher film thickness and solubility than the other sealers tested.
This paper presents a new neural network for enhancing underexposed photos. Instead of directly learning an image-to-image mapping as previous work, we introduce intermediate illumination in our ...network to associate the input with expected enhancement result, which augments the network's capability to learn complex photographic adjustment from expert-retouched input/output image pairs. Based on this model, we formulate a loss function that adopts constraints and priors on the illumination, prepare a new dataset of 3,000 underexposed image pairs, and train the network to effectively learn a rich variety of adjustment for diverse lighting conditions. By these means, our network is able to recover clear details, distinct contrast, and natural color in the enhancement results. We perform extensive experiments on the benchmark MIT-Adobe FiveK dataset and our new dataset, and show that our network is effective to deal with previously challenging images.
Native plant communities are often invaded by multiple alien species. It is still unclear how increasing diversity of alien invasive species suppresses the growth of native species and thus ...contributes to invasion success. In the subtropical monsoon region of southeast China, we experimentally created a native plant community with 18 herbaceous species. One week later, we let it be invaded by either zero (controls without invasion), one, two, four or eight alien plant species, with either high or low species evenness. After a four‐month growth period we harvested the aboveground biomass of each species. We found that increasing invasive species richness significantly increased invasive plant biomass, the biomass of all invasive and native plant species within the community, and invasion success (the ratio of invasive plant biomass to the biomass of all native and invasive plants), but it did not significantly reduce native plant biomass. Experimentally manipulating invasive species evenness did not influence invasion success and did not show any differential suppression effects on native plants. One invasive species, Sesbania cannabina, became dominant in terms of plant biomass, irrespective of its proportion in the alien plant mixtures. Throughout this experiment, effects of invasive species richness on invasion success were mainly due to such selection effects among the invasive species. On the other hand, the unchanged biomass of native species under increasing invasive plant richness suggests the presence of at least partly complementary resource niches between invasive and native species.
Current researches of action recognition which focus on single-view and multi-view recognition can hardly satisfy the requirements of human-robot interaction (HRI) applications for recognizing human ...actions from arbitrary views. Arbitrary-view recognition is still a challenging issue due to view changes and visual occlusions. In addition, the lack of datasets also sets up barriers. To provide data for arbitrary-view action recognition, we collect a new large-scale RGB-D action dataset for arbitrary-view action analysis, including RGB videos, depth and skeleton sequences. The dataset includes action samples captured in 8 fixed viewpoints and varying-view sequences which cover the entire 360° view angles. In total, 118 persons are invited to act 40 action categories. Our dataset involves more participants, more viewpoints and a large number of samples. More importantly, it is the first dataset containing the entire 360° varying-view sequences. The dataset provides sufficient data for multi-view, cross-view and arbitrary-view action analysis. Besides, we propose a View-guided Skeleton CNN (VS-CNN) to tackle the problem of arbitrary-view action recognition. Experiment results show that the VS-CNN achieves superior performance, and our dataset provides valuable but challenging data for the evaluation of arbitrary-view recognition.
In 2D semiconductors, doping offers an effective approach to modulate their optical and electronic properties. Here, an in situ doping of oxygen atoms in monolayer molybdenum disulfide (MoS2) is ...reported during the chemical vapor deposition process. Oxygen concentrations up to 20–25% can be reliable achieved in these doped monolayers, MoS2‐xOx. These oxygen dopants are in a form of substitution of sulfur atoms in the MoS2 lattice and can reduce the bandgap of intrinsic MoS2 without introducing in‐gap states as confirmed by photoluminescence spectroscopy and scanning tunneling spectroscopy. Field effect transistors made of monolayer MoS2‐xOx show enhanced electrical performances, such as high field‐effect mobility (≈100 cm2 V−1 s−1) and inverter gain, ultrahigh devices’ on/off ratio (>109) and small subthreshold swing value (≈80 mV dec−1). This in situ oxygen doping technique holds great promise on developing advanced electronics based on 2D semiconductors.
In situ oxygen substitutional doping in MoS2 monolayers is achieved by a one‐step chemical vapor deposition process and lateral heterostructures with controlled doping concentrations are reliably fabricated. The bandgap tuniability (from 2.25 to 1.75 eV) and n‐doping electronic properties are relized. This nondestructive oxygen doping technique holds great promise on future electronics based on 2D semiconductors.
Proteins used for the formation of light weight and mechanically strong biological fibers are typically composed of folded rigid and unfolded flexible units. In contrast to fibrous proteins, globular ...proteins are generally not regarded as a good candidate for fiber production due to their intrinsic structural defects. Thus, it is challenging to develop an efficient strategy for the construction of mechanically strong fibers using spherical proteins. Herein, we demonstrate the production of robust protein fibers from bovine serum albumin (BSA) using a microfluidic technique. Remarkably, the toughness of the fibers was up to 143 MJ m−3, and after post‐stretching treatment, their breaking strength increased to almost 300 MPa due to the induced long‐range ordered structure in the fibers. The performance is comparable to or even higher than that of many recombinant spider silks or regenerated silkworm fibers. Thus, this work opens a new way for making biological fibers with high performance.
A robust protein fiber is produced from globular bovine serum albumin (BSA) using a microfluidic technique. This involves the use of glutaraldehyde to crosslink the proteins during the spinning process to improve the mechanical performance of the fiber. The strength of these fibers is comparable to or even higher than that of many recombinant spider silks or regenerated silkworm fibers.
Large scale epitaxial growth and transfer of monolayer MoS2 has attracted great attention in recent years. Here, we report the wafer-scale epitaxial growth of highly oriented continuous and uniform ...monolayer MoS2 films on single-crystalline sapphire wafers by chemical vapor deposition (CVD) method. The epitaxial film is of high quality and stitched by many 0°, 60° domains and 60°-domain boundaries. Moreover, such wafer-scale monolayer MoS2 films can be transferred and stacked by a simple stamp-transfer process, and the substrate is reusable for subsequent growth. Our progress would facilitate the scalable fabrication of various electronic, valleytronic, and optoelectronic devices for practical applications.
NOTCH2NLC GGC repeat expansions were recently identified in neuronal intranuclear inclusion disease (NIID); however, it remains unclear whether they occur in other neurodegenerative disorders. This ...study aimed to investigate the role of intermediate‐length NOTCH2NLC GGC repeat expansions in Parkinson disease (PD). We screened for GGC repeat expansions in a cohort of 1,011 PD patients and identified 11 patients with intermediate‐length repeat expansions ranging from 41 to 52 repeats, with no repeat expansions in 1,134 controls. Skin biopsy revealed phospho‐alpha‐synuclein deposition, confirming the PD diagnosis in 2 patients harboring intermediate‐length repeat expansions instead of NIID or essential tremor. Fibroblasts from PD patients harboring intermediate‐length repeat expansions revealed NOTCH2NLC upregulation and autophagic dysfunction. Our results suggest that intermediate‐length repeat expansions in NOTCH2NLC are potentially associated with PD. ANN NEUROL 2021;89:182–187
Abstract
Detection of low abundance target DNA/RNA for clinical or research purposes is challenging because the target sequences can be hidden under a large background of human genomic or non-human ...metagenomic sequences. We describe a probe-based capture method to enrich for target sequences with DNA-clicked iron oxide nanoparticles. Our method was tested against commercial capture assays using streptavidin beads, on a set of probes derived from a common genotype of the hepatitis C virus. We showed that our method is more specific and sensitive, most likely due to the combination of an inert silica coating and a high density of DNA probes clicked to the nanoparticles. This facilitates target capture below the limits of detection for TaqMan qPCR, and we believe that this method has the potential to transform management of infectious diseases.
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