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Energetic hollow microcapsules (EHMs) were designed as dual-functional sensitizers for emulsion explosive with pentane/TiH2 and poly(methyl methacrylate) (PMMA) as core and shell, respectively. SEM...

A novel energetic microsphere with multicore hollow structure and uniform particle size is prepared by an improved suspension polymerization-thermal expansion method with methyl methacrylate, azodicarbonamide (AC) and TiH2 powder as monomer, blowing agent and core material, respectively. The energetic hollow microspheres (EHMs) can play double roles as sensitizers and energetic additives in emulsion explosive, and experimental results show that the EHMs could increase the power of emulsion explosive without affecting its safety. This method provides a completely new idea for the development of high energy emulsion explosive.

The effect of particle size polydispersity (σD) on coal dust explosibility was studied using a 20-L spherical explosion test apparatus. Four kinds of blends with a fixed median diameter (D50) of 95 μm but varying σD of 1.18, 1.70, 1.96 and 2.40, were prepared by mixing original coal samples with relative low σD. Experimental results showed that the values of maximum pressure rise (Pex) and maximum rate of pressure rise ((dP/dt)ex·V1/3) of coal blends with the same D50 of 95 μm varied largely with different σD, and bigger σD produced larger Pex and (dP/dt)ex·V1/3 values. The Sauter mean diameter (D3,2) presented the best correlation between particle size and the explosion parameters for the blended coal samples. Risk assessment evaluation of coal dust should be reported in terms of D3,2 and σD to avoid serious underestimation.

Graph neural networks (GNNs) provide powerful insights for brain neuroimaging technology from the view of graphical networks. However, most existing GNN-based models assume that the neuroimaging-produced brain connectome network is a homogeneous graph with single types of nodes and edges. In fact, emerging studies have reported and emphasized the significance of heterogeneity among human brain activities, especially between the two cerebral hemispheres. Thus, homogeneous-structured brain network-based graph methods are insufficient for modelling complicated cerebral activity states. To overcome this problem, in this paper, we present a heterogeneous graph neural network (HebrainGNN) for multimodal brain neuroimaging fusion learning. We first model the brain network as a heterogeneous graph with multitype nodes (i.e., left and right hemispheric nodes) and multitype edges (i.e., intra- and interhemispheric edges). Then, we propose a self-supervised pretraining strategy based on a heterogeneous brain network to address the potential overfitting problem caused by the conflict between a large parameter size and a small medical data sample size. Our results show the superiority of the proposed model over other existing methods in brain-related disease prediction tasks. Ablation experiments show that our heterogeneous graph-based model attaches more importance to hemispheric connections that may be neglected due to their low strength by previous homogeneous graph models. Other experiments also indicate that our proposed model with a pretraining strategy alleviates the problem of limited labelled data and yields a significant improvement in accuracy.

Vessel tracing by modeling vascular structures in 3D medical images with centerlines and radii can provide useful information for vascular health. Existing algorithms have been developed but there are certain persistent problems such as incomplete or inaccurate vessel tracing, especially in complicated vascular beds like the intracranial arteries. We propose here a deep learning based open curve active contour model (DOST) to trace vessels in 3D images. Initial curves were proposed from a centerline segmentation neural network. Then data-driven machine knowledge was used to predict the stretching direction and vessel radius of the initial curve, while the active contour model (as human knowledge) maintained smoothness and intensity fitness of curves. Finally, considering the nonloop topology of most vasculatures, individually traced vessels were connected into a tree topology by applying a minimum spanning tree algorithm on a global connection graph. We evaluated DOST on a Time-of-Flight (TOF) MRA intracranial artery dataset and demonstrated its superior performance over existing segmentation-based and tracking-based vessel tracing methods. In addition, DOST showed strong adaptability on different imaging modalities (CTA, MR T1 SPACE) and vascular beds (coronary arteries)., Comment: MICCAI 2021

The flame propagation through TiH2 dust cloud at near constant pressure condition is studied in a series of experiments using an apparatus with transparent latex balloons. The influential factors for the combustion performance of TiH2 dust cloud, including dust concentration, particle size, scale of isobaric space and oxygen content are investigated. Results show that the burning velocity increases with dust concentration in the fuel-lean mixtures, and then plateaus after crossing the stoichiometric condition, while the trend of flame speed changing with dust concentration varies for different mean particle sizes (D50) of 48 and 106 μm. The flame propagation speed of dust cloud is positively correlated to the isobaric space scale and oxygen content. The burning mechanism of TiH2 dust is thought to be mainly controlled by diffusion regime, the appearance of hydrogen gas accelerates the combustion rate of TiH2 particles and also makes the TiH2 dust changed from a discrete media to a continuum, which may account for the phenomenon that the flame speed in dust cloud of TiH2 is larger than that of Ti at the same concentration no matter in air or oxygen atmosphere.

Endothelial-derived factors regulate a wide range of pathophysiological events. It has been reported previously that IL-33 promotes acute kidney injury (AKI) in mice although the underlying epigenetic mechanism is unclear. In the present study we investigated the role of BRG1, a chromatin remodeling protein, in AKI with a focus on its regulation of IL-33 expression in endothelial cells. Smarca4-flox mice were crossbred with Cdh5-Cre mice to achieve endothelial-specific deletion of BRG1. AKI was induced by unilateral renal ischemia followed by reperfusion. Compared to wild type (WT) littermates, endothelial conditional BRG1 knockout (CKO) mice were protected from ischemia-reperfusion induced AKI as evidenced by decreased plasma creatinine levels, attenuated caste and tubular necrosis, and diminished immune infiltrates. CKO mice also developed less severe renal fibrosis as indicated by expression levels of extracellular matrix proteins, picrosirius red staining of collagenous tissues, and quantification of renal hydroxylproline levels. Of interest, renal expression of IL-33 was down-regulated as result of endothelial BRG1 deficiency. In cultured endothelial cells, BRG1 directly bound to the IL-33 promoter to activate transcription. Endothelial cell-derived conditioned media promoted the synthesis of pro-fibrogenic proteins in renal tubular epithelial cells. Knockdown of either BRG1 or IL-33 in endothelial cells blunted the pro-fibrogenic response in renal tubular epithelial cells. In conclusion, we propose that BRG1 may contribute to ischemia-reperfusion induced renal injury and fibrosis by promoting IL-33 transcription in endothelial cells.

In this study, daidzein long-circulating liposomes (DLCL) were prepared using the ultrasonication and lipid film-hydration method. The optimized preparation conditions by the orthogonal design was as follows: 55 to 40 for the molar ratio of soybean phosphatidylcholine (SPC) to cholesterol, 1 to 10 for the mass ratio of daidzein to total lipid (SPC and cholesterol) (w:w), the indicated concentration of 5% DSPE-mPEG2000 (w:w), 50 °C for the hydration temperature, and 24 min for the ultrasonic time. Under these conditions, the encapsulation efficiency and drug loading of DLCL were 85.3 ± 3.6% and 8.2 ± 1.4%, respectively. The complete release times of DLCL in the medium of pH 1.2 and pH 6.9 increased by four- and twofold of that of free drugs, respectively. After rats were orally administered, a single dose of daidzein (30 mg/kg) and DLCL (containing equal dose of daidzein), respectively, and the MRT0−t (mean residence time, which is the time required for the elimination of 63.2% of drug in the body), t1/2 (the elimination half-life, which is the time required to halve the plasma drug concentration of the terminal phase), and AUC0−t (the area under the plasma drug concentration-time curve, which represents the total absorption after a single dose and reflects the drug absorption degree) of daidzein in DLCL group, increased by 1.6-, 1.8- and 2.5-fold as compared with those in the free group daidzein. Our results indicated that DLCL could not only reduce the first-pass effect of daidzein to promote its oral absorption, but also prolong its mean resident time to achieve the slow-release effect.

In this paper, we address the multiframe super resolution problem from a set of degraded, under-sampled, shifted and rotated low resolution images to obtain a high resolution image using the variational Bayesian methods. In the Bayesian framework a prior model on the high resolution image need to be specified, its aim is to summarize our knowledge of the image and to constraint the ill-posed image reconstruction problem. Appropriate prior model selection according to the super resolution scenario is a critical issue. Here we propose the one-parameter l1 prior. Experimental results demonstrate that the proposed method is very effective and compared favorably to state-of-the-art super resolution algorithms.

A series of silica-pillared zirconium phosphate materials with ordered structure were synthesized using hexadecylamine (HDA) as expanding agent, dodecyl dimethyl benzyl ammonium chloride (DDBAC) as template agent and tetraethyl orthosilicate (TEOS) as silica source. The textural properties of the materials can be effectively controlled by adjusting the dosage of HDA, DDBAC and TEOS. Furthermore, a template-directing self-assembly mechanism was proposed based on the synthesis. In the epoxidation of methyl soyate, the prepared materials showed excellent performance with 95.9 % conversion of double bonds and 84.7 % epoxy selectivity. This result is determined by the large surface area and the ordered interlayer structure. Series silica-pillared zirconium phosphate materials with ordered structure were synthesized. The textural properties of the materials can be effectively controlled by adjusting the dosage of each reaction species. A template-directing self-assembly mechanism was proposed based on the synthesis. The materials show excellent catalytic performance on the epoxidation of methyl soyate.

By using methylamine as the colloidization agent to weaken the interactions of α-ZrP laminate, the quaternary ammonium salts of DTAB, TTAB, CTAB and STAB were successfully intercalated into the methylamine pre-pillared α-ZrP, denoted as DTAB-ZrP, TTAB-ZrP, CTAB-ZrP and STAB-ZrP, respectively. XRD, FTIR, TEM and N 2 sorption were used to characterize the intercalated compounds, and the arrangements of intercalated quaternary ammonium salts within ZrP were supposed according to the results. It was shown that the interlayer distances were increased from 0.76 nm to 2.10–3.50 nm and the intercalated quaternary amine salt cationic bonded with P O − anion through electrostatic interaction. The phenolic compounds adsorption results have demonstrated that all the four intercalated compounds have good adsorption performance, and CTAB-ZrP show the highest maximum adsorption amounts of 0.90, 1.25 and 1.34 mmol g −1 , for phenol, 2-chlorophenol and 2,4-dichlorophenolare, respectively. The adsorption isotherms of phenolic compounds are linear with the C 0 of 2.0–6.0 mmol L −1 and fit well to both the Linear and the Freundlich models, which indicated that the adsorption mechanism is mainly partition effects of organic phase within ZrP interlayer.

Nanoporous metals are now attracting more and more attention for their novel physical, chemical and mechanical properties. It is of great scientific and engineering significance to deposit nano-structure on macro-component surface to locally achieve nano-properties for potential applications. Laser deposition offers a promising approach to deposit a designed structure with designed composition on any location of a component.Nanoporous copper coatings with nano scale porosities were fabricated in this work by laser deposition and dealloying of copper alloy layer on macro-component surface. The fabrication process is constituted of three steps: 1) laser deposition of a MnxCu1-x powder mixture on steel substrates to obtain layers with exact composition; 2) high speed laser remelting of alloy layers to obtain microstructure refinement and composition homogeneity; 3) electrochemical dealloying of remelted layers to obtain nanoporous structure. Dealloying potential and alloy coatings’ composition take important part in microstructure evolution of nanoporous copper, with great impacts on both size and morphology of the nanoporous structure. Microstructural investigations confirm that there is a critical dealloying potential for nanoporous structure formation. When the potential set to a low level, dissolution of Mn as well as pores evolution is restrained. When the potential set to a high level above the critical, dissolution of Mn gets accelerated resulting in pore coarsening. Moreover, alloy coatings with different chemical compositions result in nanoporous coatings with different microstructures, when dealloyed on their own critical potentials.Nanoporous metals are now attracting more and more attention for their novel physical, chemical and mechanical properties. It is of great scientific and engineering significance to deposit nano-structure on macro-component surface to locally achieve nano-properties for potential applications. Laser deposition offers a promising approach to deposit a designed structure with designed composition on any location of a component.Nanoporous copper coatings with nano scale porosities were fabricated in this work by laser deposition and dealloying of copper alloy layer on macro-component surface. The fabrication process is constituted of three steps: 1) laser deposition of a MnxCu1-x powder mixture on steel substrates to obtain layers with exact composition; 2) high speed laser remelting of alloy layers to obtain microstructure refinement and composition homogeneity; 3) electrochemical dealloying of remelted layers to obtain nanoporous structure. Dealloying potential and alloy coatings’ composition take important...

In order to increase wear resistance investigations of locomotive engine parts on the comparison of different techniques for surface treatment were undertaken and compared with respect to their best fit for purpose. Base of the development was to improve the resistance of cylinder liners against abrasive wear in the region of the upper dead centre as well as of piston ring grooves against wear and deformation. Techniques compared are laser transformation hardening and laser-assisted alloying. During surface characterisation and wear tests alloyed surfaces have shown a better integrity of the surface and slightly smaller abrasion. The break out of Steadite grains observed in the hardened surfaces will increase the capacity of lubricant storage and improve failsafe running functions. This effect makes transformation hardening the preferred technique for cylinder liner treatment. For the piston ring grooves careful analysis has proven the equivalence of the techniques. For reasons of simplicity in production also transformation hardening will be preferred. However, the balance will turn according to the field tests of the components which are currently under appraisal.In order to increase wear resistance investigations of locomotive engine parts on the comparison of different techniques for surface treatment were undertaken and compared with respect to their best fit for purpose. Base of the development was to improve the resistance of cylinder liners against abrasive wear in the region of the upper dead centre as well as of piston ring grooves against wear and deformation. Techniques compared are laser transformation hardening and laser-assisted alloying. During surface characterisation and wear tests alloyed surfaces have shown a better integrity of the surface and slightly smaller abrasion. The break out of Steadite grains observed in the hardened surfaces will increase the capacity of lubricant storage and improve failsafe running functions. This effect makes transformation hardening the preferred technique for cylinder liner treatment. For the piston ring grooves careful analysis has proven the equivalence of the techniques. For reasons of simplicity in production...

Based on a 529-actuator adaptive optic (AO) system, the sparseness of slope response matrix from deformable mirror to Hartmann wavefront sensor and the sparseness of iterative matrix in wavefront reconstruction are analyzed. The influence of actuator coupling coefficient on the slope response matrix sparseness, the iterative matrix sparseness, and the AO system correction quality are also studied under the condition of constant actuator spacing. Larger coupling coefficient results in a lower sparseness of slope response matrix and an iterative matrix. Too large or too small coupling coefficient will lead to lower stability and correction quality of AO system. Finally, the optimal range of coupling coefficient is provided by the balancing correction quality, sparseness of slope response matrix, and stability.

The nanoporous metal is fabricated by means of hybrid laser processing in combination with electrochemical dealloying. Cu-Mn alloy coatings with fine shape, low dilute ratio and refined microstructure are fabricated on medium carbon steel by means of laser processing. Polarization curve indicates that the Cu-Mn alloy shows selective dissolution characteristics for different electrolytes. Nanoporous Cu and nanoporous Mn are fabricated with optimal electrochemically dealloying parameters. Nanoporous Cu has pore sizes rangeing from 30 to 50 nm, while the surface morphology of the porous Mn shows a ribbon-like structure with ultrahigh roughness factor up to 900. Finally, the potential-pH diagram is used to explain the mechanism of the dealloying.