5,131 research outputs found
First-principles study, fabrication and characterization of (Zr0.25Nb0.25Ti0.25V0.25)C high-entropy ceramic
The formation possibility of a new (Zr0.25Nb0.25Ti0.25V0.25)C high-entropy
ceramic (ZHC-1) was first analyzed by the first-principles calculations and
thermodynamical analysis and then it was successfully fabricated by hot
pressing sintering technique. The first-principles calculation results showed
that the mixing enthalpy of ZHC-1 was 5.526 kJ/mol and the mixing entropy of
ZHC-1 was in the range of 0.693R-1.040R. The thermodynamical analysis results
showed that ZHC-1 was thermodynamically stable above 959 K owing to its
negative mixing Gibbs free energy. The experimental results showed that the
as-prepared ZHC-1 (95.1% relative density) possessed a single rock-salt crystal
structure, some interesting nanoplate-like structures and high compositional
uniformity from nanoscale to microscale. By taking advantage of these unique
features, compared with the initial metal carbides (ZrC, NbC, TiC and VC), it
showed a relatively low thermal conductivity of 15.3 + - 0.3 W/(m.K) at room
temperature, which was due to the presence of solid solution effects,
nanoplates and porosity. Meanwhile, it exhibited the relatively high
nanohardness of 30.3 + - 0.7 GPa and elastic modulus of 460.4 + - 19.2 GPa and
the higher fracture toughness of 4.7 + - 0.5 MPa.m1/2, which were attributed to
the solid solution strengthening mechanism and nanoplate pullout and microcrack
deflection toughening mechanism.Comment: 49 pages,6 figures, 4 table
Oxygen uptake rate (OUR) control strategy for improving avermectin B1a production during fed-batch fermentation on industrial scale (150 m3)
Glucose metabolism plays a crucial role in the process of avermectin B1a biosynthesis. Controlling glucose feeding based on oxygen uptake rate (OUR) was established to improve the efficiency of avermectin B1a production. The result showed that avermectin B1a production was greatly enhanced by OUR control strategy. In the glucose feeding phase, OUR was maintained at approximate 12 mmol/L/h, which was conducive to avermectin B1a biosynthesis. Using this OUR control strategy, an adequate supply of organic acid precursors produced avermectin B1a 5228 U/mL, which was 22.8% higher than that of the control (batch fermentation, 4256 U/mL) on industrial scale.Key words: Avermectin B1a, glucose feeding, oxygen uptake rate, industrial scale
Improved fuzzy logic method to distinguish between meteorological and non-meteorological echoes using C-band polarimetric radar data
To obtain better performance of meteorological applications, it is necessary to distinguish radar echoes from meteorological and non-meteorological targets. After a comprehensive analysis of the computational efficiency and radar system characteristics, we propose a fuzzy logic method that is similar to the MetSignal algorithm; the performance of this method is improved significantly in weak-signal regions where polarimetric variables are severely affected by noise. In addition, post-processing is adjusted to prevent anomalous propagation at a far range from being misclassified as meteorological echo. Moreover, an additional fuzzy logic echo classifier is incorporated into post-processing to suppress misclassification in the melting layer. An independent test set is selected to evaluate algorithm performance, and the statistical results show an improvement in the algorithm performance, especially with respect to the classification of meteorological echoes in weak-signal regions
Exploiting Modality-Specific Features For Multi-Modal Manipulation Detection And Grounding
AI-synthesized text and images have gained significant attention,
particularly due to the widespread dissemination of multi-modal manipulations
on the internet, which has resulted in numerous negative impacts on society.
Existing methods for multi-modal manipulation detection and grounding primarily
focus on fusing vision-language features to make predictions, while overlooking
the importance of modality-specific features, leading to sub-optimal results.
In this paper, we construct a simple and novel transformer-based framework for
multi-modal manipulation detection and grounding tasks. Our framework
simultaneously explores modality-specific features while preserving the
capability for multi-modal alignment. To achieve this, we introduce
visual/language pre-trained encoders and dual-branch cross-attention (DCA) to
extract and fuse modality-unique features. Furthermore, we design decoupled
fine-grained classifiers (DFC) to enhance modality-specific feature mining and
mitigate modality competition. Moreover, we propose an implicit manipulation
query (IMQ) that adaptively aggregates global contextual cues within each
modality using learnable queries, thereby improving the discovery of forged
details. Extensive experiments on the dataset demonstrate the
superior performance of our proposed model compared to state-of-the-art
approaches.Comment: This work has been submitted to the IEEE for possible publication.
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Functional variant of the carboxypeptidase M (CPM) gene may affect silica-related pneumoconiosis susceptibility by its expression: a multistage case-control study.
ObjectivesIn a genome-wide association study, we discovered chromosome 12q15 (defined as rs73329476) as a silica-related pneumoconiosis susceptibility region. However, the causal variants in this region have not yet been reported.MethodsWe systematically screened eight potentially functional single-neucleotide polymorphism (SNPs) in the genes near rs73329476 (carboxypeptidase M (CPM) and cleavage and polyadenylation specific factor 6 (CPSF6)) in a case-control study including 177 cases with silicosis and 204 healthy controls, matched to cases with years of silica dust exposure. We evaluated the associations between these eight SNPs and the development of silicosis. Luciferase reporter gene assays were performed to test the effects of selected SNP on the activity of CPM in the promoter. In addition, a two-stage case-control study was performed to investigate the expression differences of the two genes in peripheral blood leucocytes from a total of 64 cases with silicosis and 64 healthy controls with similar years of silica dust exposure as the cases.ResultsWe found a strong association between the mutant rs12812500 G allele and the susceptibility of silicosis (OR=1.45, 95% CI 1.03 to 2.04, p=0.034), while luciferase reporter gene assays indicated that the mutant G allele of rs12812500 is strongly associated with increased luciferase levels compared with the wild-type C allele (p<0.01). Moreover, the mRNA (peripheral blood leucocytes) expression of the CPM gene was significantly higher in subjects with silicosis compared with healthy controls.ConclusionsThe rs12812500 variant of the CPM gene may increase silicosis susceptibility by affecting the expression of CPM, which may contribute to silicosis susceptibility with biological plausibility
Gauge-boson propagator in out of equilibrium quantum-field system and the Boltzmann equation
We construct from first principles a perturbative framework for studying
nonequilibrium quantum-field systems that include gauge bosons. The system of
our concern is quasiuniform system near equilibrium or nonequilibrium
quasistationary system. We employ the closed-time-path formalism and use the
so-called gradient approximation. No further approximation is introduced. We
construct a gauge-boson propagator, with which a well-defined perturbative
framework is formulated. In the course of construction of the framework, we
obtain the generalized Boltzmann equation (GBE) that describes the evolution of
the number-density functions of gauge-bosonic quasiparticles. The framework
allows us to compute the reaction rate for any process taking place in the
system. Various processes, in turn, cause an evolution of the systems, which is
described by the GBE.Comment: 28 page
Spectroscopic Properties, Conformation and Structure of Difluorothiophosphoryl Isocyanate in the Gaseous and Solid Phase
Schwabedissen J, Trapp PC, Stammler H-G, et al. Spectroscopic Properties, Conformation and Structure of Difluorothiophosphoryl Isocyanate in the Gaseous and Solid Phase. ChemistryOpen. 2020;9(9):913-920.Difluorothiophosphoryl isocyanate, F2P(S)NCO was characterized with UV/vis, NMR, IR (gas and Ar‐matrix), and Raman (liquid) spectroscopy. Its molecular structure was also established by means of gas electron diffraction (GED) and single crystal X‐ray diffraction (XRD) in the gas phase and solid state, respectively. The analysis of the spectroscopic data and molecular structures is complemented by extensive quantum‐chemical calculations. Theoretically, the Cs symmetric syn‐conformer is predicted to be the most stable conformation. Rotation about the P−N bond requires about 9 kJ mol−1 and the predicted existence of an anti‐conformer is dependent on the quantum‐chemical method used. This syn‐orientation of the isocyanate group is the only one found in the gas phase and contained likewise in the crystal. The overall molecular structure is very similar in gas and solid, despite in the solid state the molecules arrange through intramolecular O⋅⋅⋅F contacts into layers, which are further interconnected by S⋅⋅⋅N, S⋅⋅⋅C and C⋅⋅⋅F contacts. Additionally, the photodecomposition of F2P(S)NCO to form CO, F2P(S)N, and F2PNCO is observed in the solid Ar‐matrix
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