152 research outputs found
Transforming low-quality sand into construction materials under 110℃ and Recycling of the Waste Solution
A strong and eco-friendly material was transformed from low-quality sand via sol-gel method with ethanol as the solvent. 110oC was chosen as a target temperature because it is the average day temperature of the moon, which may be the first place for extraterrestrial development. The appropriate KOH content and ethanol concentration can improve the reaction degree and limit the side reaction. The main results indicated that the highest compressive strength (38 MPa) of the produced material could be obtained by using 20 mass% KOH and 90 V/V% ethanol. According to XRD and FTIR analysis, the formation of sanidine, zeolite, and tetraethoxysilane is the main reason for strength enhancement. Sanidine and zeolite could fill the gap between sand particles and tetraethoxysilane is a good consolidate. Excess ethanol in the waste solution can be reused with recycle rate above 65%. The total carbon emission is 197 kg CO2 eq/m2 after recycling waste solution, which is 35.82% of that produced by normal concrete. Therefore, a tough construction material can be synthesized from lowquality sand, which can partially substitute concrete. This material can address the shortage of raw materials for concrete and can be utilised for extra-terrestrial construction
Nature of the spin resonance mode in CeCoIn
Spin-fluctuation-mediated unconventional superconductivity can emerge at the
border of magnetism, featuring a superconducting order parameter that changes
sign in momentum space. Detection of such a sign-change is experimentally
challenging, since most probes are not phase-sensitive. The observation of a
spin resonance mode (SRM) from inelastic neutron scattering is often seen as
strong phase-sensitive evidence for a sign-changing superconducting order
parameter, by assuming the SRM is a spin-excitonic bound state. Here, we show
that for the heavy fermion superconductor CeCoIn, its SRM defies
expectations for a spin-excitonic bound state, and is not a manifestation of
sign-changing superconductivity. Instead, the SRM in CeCoIn likely arises
from a reduction of damping to a magnon-like mode in the superconducting state,
due to its proximity to magnetic quantum criticality. Our findings emphasize
the need for more stringent tests of whether SRMs are spin-excitonic, when
using their presence to evidence sign-changing superconductivity.Comment: accepted for publication in Communications Physic
Robust Upward Dispersion of the Neutron Spin Resonance in the Heavy Fermion Superconductor CeYbCoIn
The neutron spin resonance is a collective magnetic excitation that appears
in copper oxide, iron pnictide, and heavy fermion unconventional
superconductors. Although the resonance is commonly associated with a
spin-exciton due to the ()-wave symmetry of the superconducting
order parameter, it has also been proposed to be a magnon-like excitation
appearing in the superconducting state. Here we use inelastic neutron
scattering to demonstrate that the resonance in the heavy fermion
superconductor CeYbCoIn with has a ring-like
upward dispersion that is robust against Yb-doping. By comparing our
experimental data with random phase approximation calculation using the
electronic structure and the momentum dependence of the -wave
superconducting gap determined from scanning tunneling microscopy for
CeCoIn, we conclude the robust upward dispersing resonance mode in
CeYbCoIn is inconsistent with the downward dispersion
predicted within the spin-exciton scenario.Comment: Supplementary Information available upon reques
Valley: Video Assistant with Large Language model Enhanced abilitY
Large language models (LLMs), with their remarkable conversational
capabilities, have demonstrated impressive performance across various
applications and have emerged as formidable AI assistants. In view of this, it
raises an intuitive question: Can we harness the power of LLMs to build
multimodal AI assistants for visual applications? Recently, several multi-modal
models have been developed for this purpose. They typically pre-train an
adaptation module to align the semantics of the vision encoder and language
model, followed by fine-tuning on instruction-following data. However, despite
the success of this pipeline in image and language understanding, its
effectiveness in joint video and language understanding has not been widely
explored. In this paper, we aim to develop a novel multi-modal foundation model
capable of comprehending video, image, and language within a general framework.
To achieve this goal, we introduce Valley, a Video Assistant with Large
Language model Enhanced abilitY. The Valley consists of a LLM, a temporal
modeling module, a visual encoder, and a simple projection module designed to
bridge visual and textual modes. To empower Valley with video comprehension and
instruction-following capabilities, we construct a video instruction dataset
and adopt a two-stage tuning procedure to train it. Specifically, we employ
ChatGPT to facilitate the construction of task-oriented conversation data
encompassing various tasks, including multi-shot captions, long video
descriptions, action recognition, causal relationship inference, etc.
Subsequently, we adopt a pre-training-then-instructions-tuned pipeline to align
visual and textual modalities and improve the instruction-following capability
of Valley. Qualitative experiments demonstrate that Valley has the potential to
function as a highly effective video assistant that can make complex video
understanding scenarios easy
Machine learning reveals neutrophil-to-lymphocyte ratio as a crucial prognostic indicator in severe Japanese encephalitis patients
Japanese encephalitis (JE) is a severe infectious disease affecting the central nervous system (CNS). However, limited risk factors have been identified for predicting poor prognosis (PP) in adults with severe JE. In this study, we analyzed clinical data from thirty-eight severe adult JE patients and compared them to thirty-three patients without organic CNS disease. Machine learning techniques employing branch-and-bound algorithms were used to identify clinical risk factors. Based on clinical outcomes, patients were categorized into two groups: the PP group (mRs ≥ 3) and the good prognosis (GP) group (mRs ≤ 2) at three months post-discharge. We found that the neutrophil-to-lymphocyte ratio (NLR) and the percentage of neutrophilic count (N%) were significantly higher in the PP group compared to the GP group. Conversely, the percentage of lymphocyte count (L%) was significantly lower in the PP group. Additionally, elevated levels of aspartate aminotransferase (AST) and blood glucose were observed in the PP group compared to the GP group. The clinical parameters most strongly correlated with prognosis, as indicated by Pearson correlation coefficient (PCC), were NLR (PCC 0.45) and blood glucose (PCC 0.45). In summary, our findings indicate that increased serum NLR, N%, decreased L%, abnormal glucose metabolism, and liver function impairment are risk factors associated with poor prognosis in severe adult JE patients
High-energy magnetic excitations from heavy quasiparticles in CeCuSi
Magnetic fluctuations is the leading candidate for pairing in cuprate,
iron-based and heavy fermion superconductors. This view is challenged by the
recent discovery of nodeless superconductivity in CeCuSi, and calls for
a detailed understanding of the corresponding magnetic fluctuations. Here, we
mapped out the magnetic excitations in \ys{superconducting (S-type)}
CeCuSi using inelastic neutron scattering, finding a strongly
asymmetric dispersion for ~meV, which at higher energies evolve
into broad columnar magnetic excitations that extend to meV. While
low-energy magnetic excitations exhibit marked three-dimensional
characteristics, the high-energy magnetic excitations in CeCuSi are
almost two-dimensional, reminiscent of paramagnons found in cuprate and
iron-based superconductors. By comparing our experimental findings with
calculations in the random-phase approximation,we find that the magnetic
excitations in CeCuSi arise from quasiparticles associated with its
heavy electron band, which are also responsible for superconductivity. Our
results provide a basis for understanding magnetism and superconductivity in
CeCuSi, and demonstrate the utility of neutron scattering in probing
band renormalization in heavy fermion metals
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