Yanshan University

About: Yanshan University is a education organization based out in Qinhuangdao, China. It is known for research contribution in the topics: Microstructure & Control theory. The organization has 19544 authors who have published 16904 publications receiving 184378 citations. The organization is also known as: Yānshān dàxué.

Construction of a novel hierarchical structured NH4-Co-Ni phosphate toward an ultrastable aqueous hybrid capacitor

Abstract: Aqueous hybrid capacitors (HCs) suffer from sacrificed power density and long cycle life due to the insufficient electric conductivity and poor chemical stability of the battery-type electrode material. Herein, we report a novel NH4-Co-Ni phosphate with a stable hierarchical structure combining ultrathin nanopieces and single crystal microplatelets in one system, which allows for a synergistic integration of two microstructures with different length scales and different energy storage mechanisms. The microplatelets with a stable single crystal structure store charge through the intercalation of hydroxyl ions, while the ultrathin nanopieces store charge through surface redox reaction providing enhanced specific capacitance. Furthermore, the large single crystal can bridge the small nanopieces forming continuous electronic conduction paths as well as ionic conduction channels, and facilitate both electron and ion transportation in the hierarchical structure. The HC cell based on the as prepared material and a 3D hierarchical porous carbon delivers a high energy density of 29.6 Wh kg(-1) at a high power density of 11 kW kg(-1). Particularly, an ultralong cycle life along with 93.5% capacitance retention after 10,000 charge-discharge cycles is achieved, which is outstanding among the state-of-the-art aqueous HC cells.

Highly Efficient and Rapid Lead(II) Scavenging by the Natural Artemia Cyst Shell with Unique Three-Dimensional Porous Structure and Strong Sorption Affinity

Abstract: Heavy metal purification of water is a worldwide issue. In this work, we first find that the discarded Artemia cyst shell exhibits a unique three-dimensional porous structure, which can be recycled for efficient toxic Pb(II) removal. The hierarchical skeleton comprised of the macro–meso–micropore confirmation as well as 17 types of amino acid species provides fast ion accessibility and a strong sorption affinity. The results prove that an extremely rapid Pb capture is obtained in less than 2 min, strong adsorption occurs in the presence of high concentration of Ca/Mg/Na ions, and selectivity is far beyond that of the commercial 001x7 (greater than 50 times). More importantly, an efficient application is achieved with a treatment capacity of 9100 kg wastewater/kg sorbent, which is 45 times greater than the performance of commercially activated carbon and ion-exchange resin. The effluent can be dramatically reduced to below 10 μg/L level (WHO). In addition, we can also regenerate the exhausted biomaterial A...

Effects of Pore Position in Depth on Stress/Strain Concentration and Fatigue Crack Initiation

Abstract: The stress field around a pore was analyzed as a function of the pore position in depth in the surface of a linear elastic solid using finite element modeling It was found that the pore depth dominated the stress field around the pore on the surface and that the maximum stress was increased sharply when the pore intercepted with the surface at its top Given the applied nominal stress, the magnitude of the maximum main stress only depended on the relative depth of the pore, while the pore size affected the stress distribution in the surface An elastic-plastic model was also used to account for the yielding effect in the region where stress was over the yield strength The results still indicated a significant maximum stress concentration when the pore was just buried underneath the surface, but with a lowered value than that of the linear elastic model These results were consistent with the experimental observations that fatigue cracks were preferably initiated from pores and particles, which were just intercepted at their top with the sample surface or just buried beneath the surface