6,226 research outputs found
MECHANICAL RESPONSE ANALYSIS AND TREATMENT MEASURES OF PARTITION WALL OF METRO STATION
In the process of metro station construction, the partition wall is usually used to prevent the displacement of the soil behind the wall to ensure the construction platform. This research aims to analyze the response of partition wall to keep the safety of the structure. The time-horizontal displacement and cracks of the partition wall are measured during the process of metro station construction. The finite element software FLAC 3D is used to simulate the response of partition wall, and the reasons of partition wall cracking and displacement are analyzed by finite element simulation and measurement data. The stiffness and self-stability of the partition wall in the station is powerful, the stress concentration appeared on the central area and caused cracks of the partition wall. Reducing the pressure exerted on the partition wall and shifting partial pressure exerted on the partition wall by the construction of the medium plate can solve the tress concentration problem. Through the data analysis of the strengthened partition wall, the reinforcement effect is good, ensuring the safety of the subsequent construction. The causes of partition wall cracking are found during process of metro station construction, and the solution proposed in this paper is effective. Engineers can refer to this paper to analyze the response of partition wall in the construction of similar structures, which can ensure construction safety and reduce construction cost
Fragmentation function of in soft gluon factorization and threshold resummation
We study the fragmentation function of the gluon to color-octet heavy
quark-antiquark pair using the soft gluon factorization (SGF) approach, which
expresses the fragmentation function in a form of perturbative short-distance
hard part convoluted with one-dimensional color-octet soft gluon
distribution (SGD). The short distance hard part is calculated to
next-to-leading order in and a renormalization group equation for
the SGD is derived. By solving the renormalization group equation, threshold
logarithms are resummed to all orders in perturbation theory. The comparison
with gluon fragmentation function calculated in NRQCD factorization approach
indicates that the SGF formula resums a series of velocity corrections in NRQCD
which are important for phenomenological study.Comment: 38 pages, 8 figure
Sampling Can Be Faster Than Optimization
Optimization algorithms and Monte Carlo sampling algorithms have provided the
computational foundations for the rapid growth in applications of statistical
machine learning in recent years. There is, however, limited theoretical
understanding of the relationships between these two kinds of methodology, and
limited understanding of relative strengths and weaknesses. Moreover, existing
results have been obtained primarily in the setting of convex functions (for
optimization) and log-concave functions (for sampling). In this setting, where
local properties determine global properties, optimization algorithms are
unsurprisingly more efficient computationally than sampling algorithms. We
instead examine a class of nonconvex objective functions that arise in mixture
modeling and multi-stable systems. In this nonconvex setting, we find that the
computational complexity of sampling algorithms scales linearly with the model
dimension while that of optimization algorithms scales exponentially
Bilevel Fast Scene Adaptation for Low-Light Image Enhancement
Enhancing images in low-light scenes is a challenging but widely concerned
task in the computer vision. The mainstream learning-based methods mainly
acquire the enhanced model by learning the data distribution from the specific
scenes, causing poor adaptability (even failure) when meeting real-world
scenarios that have never been encountered before. The main obstacle lies in
the modeling conundrum from distribution discrepancy across different scenes.
To remedy this, we first explore relationships between diverse low-light scenes
based on statistical analysis, i.e., the network parameters of the encoder
trained in different data distributions are close. We introduce the bilevel
paradigm to model the above latent correspondence from the perspective of
hyperparameter optimization. A bilevel learning framework is constructed to
endow the scene-irrelevant generality of the encoder towards diverse scenes
(i.e., freezing the encoder in the adaptation and testing phases). Further, we
define a reinforced bilevel learning framework to provide a meta-initialization
for scene-specific decoder to further ameliorate visual quality. Moreover, to
improve the practicability, we establish a Retinex-induced architecture with
adaptive denoising and apply our built learning framework to acquire its
parameters by using two training losses including supervised and unsupervised
forms. Extensive experimental evaluations on multiple datasets verify our
adaptability and competitive performance against existing state-of-the-art
works. The code and datasets will be available at
https://github.com/vis-opt-group/BL
2,4-Dichloro-6-[2-methoxy-4-(prop-2-en-1-yl)phenoxy]-1,3,5-triazine
The title compound, C13H11Cl2N3O2, was obtained by the reaction of eugenol and cyanuric chloride. The dihedral angle between the benzene and triazine rings is 87.56 (4)°. Two C atoms of the allyl group are disordered over two sites in a 0.72 (2):0.28 (2) ratio
Quality of reporting of systematic reviews published in “evidence-based” Chinese journals
BACKGROUND: The number of systematic reviews (SRs)/meta-analyses (MAs) has increased dramatically in China over the past decades. However, evaluation of quality of reporting of systematic reviews published has not been undertaken. The objective of this study is to evaluate the quality of reporting of SRs/MAs assessing efficacy and/or harms of clinical interventions published in “evidence-based” Chinese journals. METHODS: Web-based database searches were conducted for the Chinese Journal of Evidence-based Medicine, the Journal of Evidence-Based Medicine, the Chinese Journal of Evidence Based Pediatrics, and the Chinese Journal of Evidence-Based Cardiovascular Medicine. SRs/MAs assessing efficacy and/or harms of clinical interventions were included. The cut-off was December 31st 2011. The PRISMA statement was applied to assess the quality of reporting. Each item was assessed as follows: ‘Yes’ for total compliance, scored ‘1’; ‘partial’ for partial compliance, scored ‘0.5’; and ‘No’ for non-compliance, scored ‘0’. The review was considered to have major flaws if it received a total score of ≤15.0, minor flaws if it received a total score of 15.5 to 21.0, and minimal flaws if it received a total score 21.5 to 27.0. Odds ratios were used for binary variables, and the mean difference was used for continuous variables. Analyses were performed using RevMan 5.0 software. RESULTS: Overall, 487 SRs/MAs were identified and assessed. The included reviews had medium quality with minor flaws based on PRISMA total scores (range: 8.5–26.0; mean: 19.6 ± 3.3). The stratified analysis showed that SRs/MAs with more than 3 authors, from a university, hospital + university cooperation, multiple affiliations (≥2), and funding have significantly higher quality of reporting of SRs/MAs; 58% of the included reviews were considered to have minor flaws (total score of 15.6 to 21.0). Only 9.6% of reviews were considered to have major flaws. Specific areas needing improvement in reporting include the abstract, protocol and registration, and characteristics of the search. CONCLUSIONS: The reporting of SRs published in “evidence-based” Chinese journals is poor and needs to be improved in order for reviews to be useful. SR authors should use the PRISMA checklist to ensure complete and accurate accounts of their SRs
WC@meso-Pt core–shell nanostructures for fuel cells
We developed a facile method to synthesize core–shell WC@meso-Pt nanocatalysts by carburizing ammonium tungstate and copper nitrate via gas–solid reactions, followed by a Pt replacement reaction. The mesoporous nanocomposite displays higher activity and stability towards methanol electrooxidation than commercial Pt/C catalysts
Antidiabetic retinopathy effect of Fufang Danshen Mingmu in rats
Purpose: To investigate the effect of Fufang Danshen Mingmu (FDM) on streptozotocin-induced diabetic retinopathy rats.Methods: Diabetic retinopathy model rats were prepared using a single intraperitoneal injection of a freshly prepared solution of streptozotocin (50 mg/kg). The rats were randomly divided into 6 groups of ten rats each: negative control group, control group, reference group (glibenclamide, 1 mg/kg) as well as FDM groups, (50, 100 and 200 mg/kg body weight). Blood glucose and plasma insulin levels were determined. Oxidative stress was evaluated in liver and kidney as lipid peroxidation (LPO), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GPx) and catalase (CAT). Blood serum levels of creatinine and urea were determined in both diabetic control and treated rats.Results: Compared with diabetic rats, oral administration of FDM at a dose of 200 mg/kg daily for 30 days resulted in a significant decrease in fasting blood glucose (120.21 ± 3.37 mg/dL, p < 0.05) and increased insulin level (13.31 ± 0.67 uU/mL, p < 0.05). Furthermore, it significantly reduced biochemical parameters (serum creatinine, 0.86 ±0.24 mg/dL, p < 0.05) and serum urea 41.86±1.59 mg/dL, p <0.05).Conclusion: The results indicate that FDM normalizes impaired antioxidant status in streptozotocin induced diabetic retinopathy rats, and also exerts a protective effect against lipid peroxidation by scavenging free radicals
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