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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.

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.

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.

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...

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.