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Hydroxyapatite (HA), of molecular formula Ca10(PO4)6(OH)2 is a major inorganic component of a human's hard tissue. It possesses advantageous qualities such as excellent biocompatibility and bioactivity. However, its mechanical qualities are significantly poorer, in particular its extreme brittleness. As a result, hydroxyapatite cannot be used for load-bearing implants in clinical applications. Thus, it can only be applied for unload-bearing or low-loaded implants, such as powders, coating and porous implants 1 . To combat this problem, various hydroxyapatite/polymer composites were widely constructed with hydroxyapatite and some polymers, such as polyethylene 2 , polylactic acid 3 , polymethylmethacrylate 4 , chitosan 5 , etc. These hydroxyapatite/polymer composites successfully remedied the issues associated with hydroxyapatite's mechanical properties. They are still highly biocompatible but are now much less brittle. Therefore, they can be used for bone replacement and bone tissue engineering 6,7 . Nevertheless, the interfacial bonding is very weak between the hydroxyapatite and the polymer matrix because of their significantly difference hydrophilicities. Because of this, their interface can be easily destroyed from stress or a physiological fluid when it is implanted into the body 8 . Therefore, if the hydroxyapatite/ polymer compounds fail, then implant failure would subsequently take place.

In this article, a new approach is proposed to investigate adsorption kinetics and transport of gases in shale. Due to co‐existence of pores with different size in the shale, a set of adsorption processes happened in pores of different sizes are considered. A first‐order multi‐process model is developed, which can perfectly fit the adsorption kinetic data of CH4 and CO2 obtained at different temperatures. The modeling and pore characterization results indicate that an adsorption process happens in micropores/mesopores (<50 nm) and another adsorption process happens in macropores (>50 nm) in the Wufeng shale. Gas diffusion mechanism is dominant in micropores/mesopores, and gas seepage mechanism is dominant in macropores. The effective diffusivity of CO2 is smaller than that of CH4, because the adsorption of large amount of CO2 in the pores hinders its diffusion. The coefficients related to the diffusion and seepage have no obvious trend with temperature.

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In this paper, a two gap capillary (TGC) structure is presented and the corresponding driving circuit based on surface flashover ignition is designed to achieve reliable and repetitive discharge in atmosphere. The characteristics of the two gap capillary (TGC) discharge in low energy are investigated, of which the discharge energy is from 27 J to 432 J. With the rise of charging voltage, the delay of the weak capillary discharge and the main discharge both decrease. Meanwhile, the current flowing through the main gap and the plasma jet ejection are enhanced. The main gap resistance is about several hundreds of milliohms in the main discharge and rises gradually with the decay of the current. The long tail extinction is witnessed at the relatively low charging voltage of 0.5 kV and 1.0 kV, by which the pulse width of the discharge is extended. However, the discharge during the long tail extinction contributes little to the plasma jet ejection with negligible plasma jet velocity and low degree of the plasma ionization. The effective energy deposition efficiency on the main gap increases gradually with the charging voltage and reaches approximately 2 times higher than that of the traditional structure at the charging voltage of 2.0 kV. The series inductor in the circuit can restrain the development of the long tail extinction and increase the effective energy deposition efficiency. Thus, the discharge characteristics and the plasma ejection of TGC under the relatively low charging voltage are optimized.