316 research outputs found
A multi-parameter cinematic curvature
We state a multi-parameter cinematic curvature condition, and prove
bounds for related maximal operators
Comprehensive ab initio study of effects of alloying elements on generalized stacking fault energies of Ni and NiAl
Excellent high-temperature mechanical properties of Ni-based single crystal
superalloys (NSCSs) are attributed to the yield strength anomaly of NiAl
that is intimately related to generalized stacking fault energies (GSFEs).
Therefore, clarifying the effects of alloying elements on the GSFEs is of great
significance for alloys design. Here, by means of ab initio density functional
theory calculations, we systematically calculated the GSFEs of different slip
systems of Ni and NiAl without and with alloying elements using the alias
shear method. We obtained that for Ni, except for magnetic elements Mn, Fe, and
Co, most of alloying elements decrease the unstable stacking fault energy
() of the and slip systems
and also decrease the stable stacking fault energy () of the
slip system. For NiAl, most of alloying elements in
groups IIIB-VIIB show a strong Al site preference. Except for Mn and Fe, the
elements in groups VB-VIIB and the first column of group VIII increase the
values of of different slip systems of NiAl. On the other
hand, the elements in groups IIIB-VIIB also increase the value of
. We found that Re is an excellent strengthening alloying element
that significantly increases the slip barrier of the tailing slip process for
Ni, and also enhances the slip barrier of the leading slip process of three
slip systems for NiAl. W and Mo exhibit similar effects as Re. We
predicted that Os, Ru, and Ir are good strengthening alloying elements as well,
since they show the strengthening effects on both the leading and tailing slip
process for Ni and NiAl
Development and Validation of a Prognostic Nomogram for Extremity Soft Tissue Leiomyosarcoma
Background: Extremity soft tissue leiomyosarcoma (LMS) is a rare disease with a poor prognosis. The aim of this study is to develop nomograms to predict the overall survival (OS) and cancer-specific survival (CSS) of patients with extremity soft tissue LMS.Methods: Based on the Surveillance, Epidemiology, and End Results (SEER) database, 1,528 cases of extremity soft tissue LMS diagnosed between 1983 and 2015 were included. Cox proportional hazards regression modeling was used to analyze prognosis and obtain independent predictors. The independent predictors were integrated to develop nomograms predicting 5- and 10-year OS and CSS. Nomogram performance was evaluated by a concordance index (C-index) and calibration plots using R software version 3.5.0.Results: Multivariate analysis revealed that age β₯60 years, high tumor grade, distant metastasis, tumor size β₯5 cm, and lack of surgery were significantly associated with decreased OS and CSS. These five predictors were used to construct nomograms for predicting 5- and 10-year OS and CSS. Internal and external calibration plots for the probability of 5- and 10-year OS and CSS showed excellent agreement between nomogram prediction and observed outcomes. The C-index values for internal validation of OS and CSS prediction were 0.776 (95% CI 0.752β0.801) and 0.835 (95% CI 0.810β0.860), respectively, whereas those for external validation were 0.748 (95% CI 0.721β0.775) and 0.814 (95% CI 0.785β0.843), respectively.Conclusions: The proposed nomogram is a reliable and robust tool for accurate prognostic prediction in patients with extremity soft tissue LMS
Assessing Hidden Risks of LLMs: An Empirical Study on Robustness, Consistency, and Credibility
The recent popularity of large language models (LLMs) has brought a
significant impact to boundless fields, particularly through their open-ended
ecosystem such as the APIs, open-sourced models, and plugins. However, with
their widespread deployment, there is a general lack of research that
thoroughly discusses and analyzes the potential risks concealed. In that case,
we intend to conduct a preliminary but pioneering study covering the
robustness, consistency, and credibility of LLMs systems. With most of the
related literature in the era of LLM uncharted, we propose an automated
workflow that copes with an upscaled number of queries/responses. Overall, we
conduct over a million queries to the mainstream LLMs including ChatGPT, LLaMA,
and OPT. Core to our workflow consists of a data primitive, followed by an
automated interpreter that evaluates these LLMs under different adversarial
metrical systems. As a result, we draw several, and perhaps unfortunate,
conclusions that are quite uncommon from this trendy community. Briefly, they
are: (i)-the minor but inevitable error occurrence in the user-generated query
input may, by chance, cause the LLM to respond unexpectedly; (ii)-LLMs possess
poor consistency when processing semantically similar query input. In addition,
as a side finding, we find that ChatGPT is still capable to yield the correct
answer even when the input is polluted at an extreme level. While this
phenomenon demonstrates the powerful memorization of the LLMs, it raises
serious concerns about using such data for LLM-involved evaluation in academic
development. To deal with it, we propose a novel index associated with a
dataset that roughly decides the feasibility of using such data for
LLM-involved evaluation. Extensive empirical studies are tagged to support the
aforementioned claims
Structure-driven intercalated architecture of septuple-atomic-layer family with diverse properties from semiconductor to topological insulator to Ising superconductor
Motivated by the fact that septuple-atomic-layer MnBiTe can be
structurally viewed as the combination of double-atomic-layer MnTe
intercalating into quintuple-atomic-layer BiTe, we present a general
approach of constructing twelve septuple-atomic-layer - and
- monolayer family (\emph{i} = 1 to 6) by intercalating
MoS-type monolayer into InSe-type AZ monolayer. Besides
reproducing the experimentally synthesized -MoSiN,
-WSiN and -MnBiTe monolayer materials,
another 66 thermodynamically and dynamically stable were predicted,
which span a wide range of properties upon the number of valence electrons
(VEC). with the rules of 32 or 34 VEC are mostly semiconductors with
direct or indirect band gap and, however, with 33 VEC are generally metal,
half-metal ferromagnetism, or spin-gapless semiconductor upon whether or not an
unpaired electron is spin polarized. Moreover, we propose
-WSiP for the spin-valley polarization,
-TaSiN for Ising superconductor and -SrGaSe
for topological insulator.Comment: Maintext 9 pages; 5 figures; Supplementary Materials 8 figures and 4
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