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• The feasibility of applying PTC material to infrared camouflage is discussed for the first time. • The design method of performance parameters of PTC material is proposed. • A heat transfer model of PTC material considering the effect of thermal conductivity is proposed. • The adaptive thermal control performance of PTC material in vacuum environment is studied. In order to protect important military targets from the threat of advanced infrared detection systems and guided weapons, the development of adaptive infrared decoy technology has become a top priority. In this paper, the feasibility of applying PTC material to infrared camouflage of decoy was discussed for the first time. Meanwhile, a design method for performance parameters of PTC materials that satisfy the infrared camouflage was proposed with consideration given to the complex background environment in which the space decoy was located. Taking this as a guide, the room temperature PTC materials that attain the design requirements were prepared. In this paper, the phase change characteristics of the material and the change of thermal conductivity with temperature were considered, and the heat transfer model of the PTC material was further optimized, which was verified by experiments in a vacuum environment. On this basis, the infrared camouflage properties of space decoy based on thermal control of PTC materials were further simulated. The results show that the PTC resistor prepared under the guidance of this design method can achieve a more ideal infrared camouflage effect and higher adaptive temperature control precision than ordinary resistors when applied to space decoy. The research results specify possible directions for the development and thermal control of PTC material. [ABSTRACT FROM AUTHOR]

• Designed a combustion experiment platform that can simulate high-altitude environment. • Revealed the intrinsic effect of pressure on the fluorination and oxidation of Mg. • Provided further insight into micro-scale combustion process of Mg particles. • Heterogeneous condensation reactions are innovatively treated in combustion simulation. The exploration of condensed combustion products (CCPs) is essential to reveal the ignition, combustion, and infrared radiation mechanisms of Mg-based (Magnesium/polytetrafluoroethylene/Viton) solid fuels that have been considerably employed in the field of aerospace. Systematic experiments and numerical simulations are performed with the physicochemical properties (including morphology, element distribution, phase composition and particle size distribution) and flow field distribution characteristics of CCPs, respectively. The effects of formulation and pressure on the combustion behaviors of pyrotechnic compositions are thoroughly investigated based on thermal analysis measurements, laser ignition, optical diagnosis and CCPs collection. The results demonstrated that the major solid products for all cases are MgF 2 agglomerates and MgO smoke oxide particles (SOPs). Increasing the Mg content in the formulation is simultaneously beneficial for the reduction of large agglomerates and SOPs. As the pressure is decreased from 0.1 MPa to 0.02 MPa, the volume weighted mean diameter of CCPs increases significantly due to the decrease in burning rate. The numerical model established in this paper better approximates the realistic combustion process by coupling the heterogeneous condensation reactions, and is adopted to predict the distribution of CCPs in the combustion flow field under different experimental conditions. Numerical results reveal that the MgF 2 is mainly distributed in the anaerobic combustion core zone immediately above the burning surface, while MgO is located in the peripheral aerobic combustion diffusion zone. The negative pressure environment has more profound influence on the oxidation reaction of Mg than fluorination reaction. The scientific findings are expected to facilitate the development of more complete combustion and infrared radiation models, while theoretically providing in-depth guidance for the increasing military and civilian application of Mg-based solid fuels. [ABSTRACT FROM AUTHOR]

Poly (aniline) (PANI) is considered an ideal material for the modulation of infrared (IR) radiation due to its excellent electrochromic properties. However, the camphorsulfonic acid doping mechanism which results in emittance modulation is not clearly understood. With the goal of enhancing the IR emittance variation (Δε), a PANI film was synthesized by a chemical oxidation and spraying method, and the doping mechanism of CSA concentration effect on Δε was studied by combining Raman spectra, X-ray photoelectron spectra and density functional theory calculations. The results demonstrate that with increasing camphorsulfonic acid concentration, the effect of the doping concentration on the emittance of PANI/Au films can be divided into two stages: (1) the change in the emittance is mainly caused by the shortening of optical penetration depth either under the state of dopant free (non-doped) or a low CSA doping concentration; (2) the change in emittance is mainly caused by the increase in reflectivity of the PANI layer under the increased doping. Due to the joint action of the two factors, the emittance of the PANI film first increases and then decreases with increasing concentration of CSA, and the maximum Δε (0.45) is realized at 1 M. This paper clarifies the mechanism of PANI films with different CSA dopant concentrations and could provide a way to increase the emittance modulation range by adjusting the concentration of the dopants. • Emittance variation is relevant to the changed of light penetration depth. • Improving of carrier concentration contributes to the shorten of penetration depth. • The carrier concentration evolves with the doping concentration. [ABSTRACT FROM AUTHOR]

• Designed a small-scale negative pressure combustion experiment system. • Revealed the effect of pressure on flame structure and temperature. • Demonstrated the pressure sensitivity of the burning rate under 0.02–0.1 MPa. • Predicted the combustion products distribution characteristics. The present study is devoted to comprehensively evaluating the combustion performance of Mg-based (Magnesium/polytetrafluoroethylene/Viton) solid fuels in high-altitude operating environments. A small-scale sealed CO 2 laser ignition experiment system is designed to produce different negative pressure environments. A high-speed camera (HSC) and an infrared thermal imager are used to cooperatively capture the burning process. The results obtained demonstrate that the area of the flame core zone and the flame temperature increase significantly as the pressure increases. It is conducive to the heat feedback of the gas phase reaction zone to the solid phase heating zone, resulting in an increase in the burning rate. As the Mg content increases, the flame temperature is decreased and the burning rate is increased. The burning rate for the Mg-based solid fuels is found to increase monotonically with ambient pressure and to follow the Vieille's law in the pressure range of 0.02–0.1 MPa. Based on the experiment, a three-dimensional combustion-flow coupling solution model is established including the detailed aerobic combustion reaction kinetic model and the eddy dissipation concept (EDC) model. Numerical simulation results reveal that the content of incompletely reacted Mg increases as the pressure decreases. Conversely, the decreasing behavior of oxygen partial pressure at low pressure reduces the probability of reaction of Mg with O 2 , resulting in a dramatical decrease in the mass fraction of MgO. The scientific findings provide useful insight for the deep understanding of the combustion behavior of Mg-based solid fuels, and support for the increasing demands for both military and civilian applications. [ABSTRACT FROM AUTHOR]

In recent times, complicated three-dimensional shape reconstruction from a single RGB image has become a crucial technology in many industries such as Automotive, Healthcare, and Military. It is particularly challenging to reconstruct the complex shape of a military tank. Former methods infer 3D information from 2D images via shape deformation from ellipsoids, which has the problems of local adhesion, uneven surfaces, and distortion of the structure. This study introduces a new single-view 3D shape reconstruction (SVSR) framework with multi-scale feature extraction that splits shape reconstruction into three tasks—camera parameter prediction, initial shape construction, and deformation prediction. The shape-initialization module provides a variable initial shape by predicting the stretch and displacement parameters of each geometric component based on their topological relationships. The shape-deformation module predicts the directional deformation of each vertex. These two modules are dedicated separately to avoid shape adhesion and improve the local detail performance. Silhouette images of the tank's overall shape and local geometric components are employed to eliminate the impact of component shielding and avoid structural distortion via both pixel loss and perceptual loss. Experiments on the main battle tank dataset demonstrate that our method can predict complicated 3D shapes with a low Chamfer distance value (0.0017). Our approach outperforms the other state-of-the-art methods in terms of Chamfer distance and F-score with at least a 10% improvement, with more realistic overall contours and part details. It has huge application prospects in dealing with other complex shape predictions by modifying the shape-initialization module. • A new method was proposed to reconstruct meshes of various complicated tanks from a single image. • Our framework avoids the problems of local adhesion, uneven surface and distortion of structure. • We design a Shape Initialization Module to provide a variable initial shape. • Part loss was designed to optimize the local remodelling of the object. • Multi-scale extraction and multi-path prediction structure optimized the feature processing. [ABSTRACT FROM AUTHOR]

• A deep learning model to invert thermal boundary parameters is proposed. • The combination of heat transfer and deep learning model is successful. • The proposed hybrid models outperformed the standalone models (CNN, LSTM). • It can effectively solve the complex calculation of traditional inverse methods. Estimating thermal boundary condition parameters in the transient inverse heat transfer problem (IHTP) is characterized by instability and non-uniqueness of the solution. This study formulated a simple method based on deep learning, which can realize multi-dimensional real-time prediction of thermal boundary condition parameters. The proposed model combining convolutional neural network (CNN) and long short-term memory networks (LSTM) allowed estimating multiple time-varying parameters based on the time-varying temperature field image of the target. The data-driven model used the computational fluid dynamics (CFD) method to obtain the numerical data, and the influence weight of the parameters was introduced in the training process to improve the generalization ability of the model. An experiment on the cubic cavity was made to verify the reliability of the proposed model to estimate time-varying parameters. The studies we have performed showed that the proposed hybrid models outperformed the standalone models (CNN, LSTM) in estimating multiple time-varying parameters. In the experimental results, the relative errors of air temperature and humidity were only 2.33% and 4.33%, respectively. These attempts of introducing the deep learning method to the IHTP in the present study were successful and it was significant for the study of the transient inverse heat transfer problem. [ABSTRACT FROM AUTHOR]

• Breast cancer related differentially expressed genes were identified based on TCGA database and GTEx database. • The GIMAP family genes with relatively high diagnostic values for the patients of breast cancer were analyzed. • Immune infiltration of GIMAP family genes obtained, providing selectable targets for breast cancer treatment. Breast cancer is the most common malignancy threatening women's health worldwide. The GTPase IMAP family genes are proteins belonging to the immune-associated nucleotide subfamily of the GTP-binding superfamily and nucleotide-binding proteins. However, little is known about the role of different GTPase IMAP family genes in breast cancer. We obtained differential genes from the GEPIA and UALCAN databases and then used the Kaplan–Meier plotter, The Human Protein Atlas, NetworkAnalyst, STRING, and TIMER to analyze the prognostic value, protein expression, and immune cell infiltration of the GTPase IMAP family in patients with breast cancer. Among the GIMAP family genes, the expression levels of GIMAP1, GIMAP5, GIMAP6, GIMAP7, and GIMAP8 were significantly low in breast tumor tissues. In the overall population, patients with high expression of all genes of the GIMAP family had a significantly higher overall survival (OS), with the most significant increase correlated with the GIMAP2 gene (hazard ratio [HR] = 0.45, 95% confidence interval [CI], 0.34–0.59, P = 3.1e−09). However, patients with high expression of the GIMAP family genes in triple-negative breast cancer compared to those with low expression had a significant OS benefit, with the most pronounced benefit correlated with the GIMAP2 gene (HR = 0.37, 95% CI, 0.23–0.59, P = 1.4e−05). GIMAP7 and GIMAP8 were significantly upregulated in breast tumor tissues. The expression of genes in different GIMAP families was positively correlated with the infiltration and expression of six immune cell types (B cells, CD4+ T cells, CD8+ T cells, macrophages, neutrophils, and dendritic cells). This study may provide novel insights into the selection of GIMAP family prognostic biomarkers for breast cancer. [ABSTRACT FROM AUTHOR]

• The study creates a scale measuring language disorder in Mandarin-speaking children. • MCELP-CS is beneficial in language measurement for autistic, CP, and HI children. • MCELP-CS has good internal consistency and excellent structural validity. • The MCELP-CS measured language comprehension and production across domains. To test the psychometric properties of a newly developed Mandarin Clinical Evaluation of Language for Preschooler's Core Scale (MCELP-CS). Data were collected from 379 preschool-aged participants, including 81 children with language disorders associated with clinical conditions. The 155-item MCELP-CS consists of five subscales: vocabulary comprehension (VC), sentence comprehension (SC), vocabulary naming (VN), sentence structure imitation (SSI), and story narration (SN). The scale was used to measure the receptive and expressive language abilities of children aged 3–5 years and 11 months. The Peabody Picture Vocabulary Test-revised (PPVT-R) was used to measure the receptive vocabulary abilities among the children (n = 338). The internal consistency, test-retest reliability, structural validity, convergent validity, and diagnostic accuracy were used to evaluate the scale. Differences between age groups were also examined using analysis of variance. The MCELP-CS had high internal consistency and good test-retest reliability. Fitting indices of the two-factor model from confirmatory factor analysis (CFA), including χ 2 , CFI, TLI, RSEAM, and SRMR, suggested that the model is consistent with the theoretical structure. Significant correlations between the MCELP-CS and PPVT-R showed a high convergent validity. In addition, the scale indicated good diagnostic accuracy in differentiating the language disorders of children with autism, cerebral palsy (CP), and hearing impairment (HI). The MCELP-CS is a reliable and valid diagnostic tool for language disorders of Mandarin-speaking preschool children with autism, CP, and HI. It is appropriate to collect normative data for the MCELP-CS with a large sample population of preschool children. [ABSTRACT FROM AUTHOR]

Acid fracturing is an important method of achieving high-efficiency economic development of carbonate reservoirs. The propagation of acid-etched fractures is affected significantly by geological discontinuities such as natural fractures and limestone caverns. Therefore, acid-etched fractures in carbonate reservoirs also differ greatly in morphology to those inhomogeneous reservoirs. However, no clear propagation mechanism has been available to describe and predict the propagation behavior of acid-etched fractures. In order to investigate the process, based on the extended finite element method, a set of acid-etched fracture propagation models for fracture-vuggy reservoirs, including mechanical, hydro and acid-rock reaction modules, were established. The effect of vuggy, natural fracture and acid on the initiation and propagation of induced fracture, the surface morphology of the acid-etched fractures, the effects of the number of perforation clusters, and natural limestone caverns, were considered. The calculated geometric size of the fracture was compared with the results based on the CGD (Christianovich-Geertsma-Daneshy model) model, for validating the reliability of the present model. The effects of the injection fracturing liquid type and the number of perforation clusters on fracture initiation position, propagation path, and surface morphology were evaluated. The calculation results also were compared with large-scale tri-axial physical experiment data. Finally, the fracture propagation behavior in rock samples containing natural fractures and limestone caverns was simulated in order to examine examining the effects of the limestone caverns with different sizes at different positions on the propagation path of acid-etched fractures. The interaction between induced fractures and limestone caverns was discussed. The induced fractures priority was given to activating natural fractures around the wellbore and extending along the natural fractures and tended to be deflected from the maximum horizontal principal stress direction due to the existence of caverns arrested fractures to a certain degree. • An acid-etched fracture propagation models for fracture-vuggy reservoirs was established. • The initiation and extension mechanisms were discussed. • The artificial fractures tended to initiation from the large size natural fractures near the well. [ABSTRACT FROM AUTHOR]

Stress-dependent permeability (SDP) of naturally fractured tight gas reservoir (NFTGR) has drawn considerable attention in recent decades. The SDP of natural fracture (NF) is quite different from that of the rock matrix (RM) due to the variance NF width and NF filling degree. The SDP of naturally fractures can be obtained by conducting permeability measurement experiments on naturally fractured core plugs (NFCP). However, it is usually impossible to obtain downhole NFCPs due to economic and technical limitations. Our research group obtained various types of naturally fractured downhole core plugs from a NFTGR (Tarim filed, China) and make it possible to investigate the effect of NFs on SDP. The NF types of the downhole core plugs include RM core plug (RMCP), unpenetrated-ring fractured core plug (URFCP), penetrated-vertical fractured core plug (PVFCP), penetrated-incline fractured core plug (PIFCP), unpenetrated-U-type fractured core plug (UUFCP), and multiple fractured core plug (MFCP). We conducted SDP experiments through the application of pressure-pulse-decay (PPD) method. Results showed that the initial permeability of RMCP and MFCP were higher than that of others, and the permeability vanished stress of them were also highest, indicating that the flow resistance of RMCP and MFCP were lower than those of others. It is also shown that the degree of permeability stress-dependent (DPSD) varied from NF types. A modified exponential permeability model was derived to evaluate DPSD of natural fractured core plugs. Two parameters (γ σeff and γ σeff ') were used to describe the DSDP in NFTGR, and the range of which were obtained from the experimental data by regression analysis. The reasonable γ σeff and γ σeff ' range of NFCP were also proposed in this paper. Sensitivity analysis showed that the influence γ σeff ' on SDP was more significant than that of γ σeff. The proposed model can be integrated to reservoir simulators and help to improve of oil and gas production prediction accuracy in NFTGRs. • Real downhole core plugs were used to evaluate the stress dependent permeability. • The degree of stress dependent permeability was evaluated by types of natural fractures. • An analytical model was proposed to assess the stress dependent permeability of naturally fractured reservoir. • Key parameters that control of the stress dependent permeability were identified. [ABSTRACT FROM AUTHOR]