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Lin C.X.C.,University of Queensland | Jambhrunkar S.,University of Queensland | Yuan P.,China University of PetroleumBeijing | Zhou C.H.C.,Zhejiang University of Technology | Zhao G.X.S.,University of Queensland
RSC Advances | Year: 2015

Recently many scientists are interested in replicating the unique structure and function of multi-compartments found in natural cells. Despite the success in recreating multi-compartment structures for organic materials, it is a great challenge to translate a similar concept into inorganic and hybrid materials for more versatile applications. Here, as the first example in the organosilica family, we present a facile synthesis route to create hybrid materials with a multi-compartment structure through the spontaneous assembly of fluorocarbon (FC) and hydrocarbon (HC) surfactants with the addition of co-solvent. The formation of multi-compartment periodic mesoporous organosilica (MCPMO) is triggered by the presence of organic co-solvent that induces an osmotic pressure difference in the system. The MCPMO demonstrates a high loading capacity of the antimalarial and anticancer drug artemisinin (47%) with a sustainable release profile attributed to the unique compartmentalized structure and hydrophobic properties. This synthesis strategy can be extended to design various materials with different compositions and morphologies for wider applications including microelectronics, biomedicine, catalysis and energy storage. © The Royal Society of Chemistry. Source

Li H.,Peking University | Cong Y.,Peking University | Zheng Y.,Peking University | Cui L.,China University of PetroleumBeijing
Materials Science and Engineering C | Year: 2016

In the present study, a novel kind of NiTiW shape memory alloy with chemical composition of Ni43.5Ti45.5W11 (at.%) has been successfully developed with excellent X-ray radiopacity by the introduction of pure W precipitates into the NiTi matrix phase. Its microstructure, X-ray radiopacity, mechanical properties, corrosion resistance in simulated body fluid, hemocompatibility and in vitro cytocompatibility were systematically investigated. The typical microstructural feature of NiTiW alloy at room temperature was tiny pure W particles randomly distributing in the NiTi matrix phase. The presence of W precipitates was found to result in enhanced radiopacity and microhardness of NiTiW alloy in comparison to that of NiTi binary alloy. NiTiW alloy exhibits excellent shape memory effect, and a maximum shape recovery ratio of about 30% was obtained with a total prestrain of 8% for the NiTiW alloy sample. In the electrochemical test, NiTiW alloy presented an excellent corrosion resistance in simulated body fluid, comparable to that of NiTi alloy. Hemocompatibility tests indicated that the NiTiW alloy has quite low hemolysis (lower than 0.5%) and the adherent platelet showed round shape without pseudopod. Besides, in vitro cell viability tests demonstrated that the cell viability is all above 90%, and the cells spread well on the NiTiW alloy, having polygon or spindle healthy morphology. The hemocompatibility tests, in vitro cell viability tests and morphology observation indicated that the NiTiW shape memory alloys have excellent biocompatibility. The excellent X-ray radiopacity makes the NiTiW alloys show obvious advantages in orthopedic, stomatological, neurological and cardiovascular domains where radiopacity is quite important factor in order to guarantee successful implantation. © 2015 Published by Elsevier B.V. Source

Zhu D.,China University of PetroleumBeijing | Sharma A.Z.,University of Manitoba | Wiebe C.R.,University of Winnipeg | Budzelaar P.H.M.,University of Manitoba
Dalton Transactions | Year: 2015

Oxidation of (MeBDI)Rh(cyclooctene) (MeBDI = [2,6-Me2C6H3NCMe]2CH) with Br2 or I2 produces paramagnetic halide-bridged RhII dimers [(MeBDI)Rh]2(μ-X)2 without a direct Rh-Rh bond. Steric factors are proposed to play a key role in preventing the formation of Rh-Rh bonded alternative structures. This journal is © The Royal Society of Chemistry. Source

Wei J.-G.,Northeast Petroleum University | Yan C.-L.,China University of PetroleumQingdao | Yan C.-L.,China University of PetroleumBeijing
Geomechanics and Engineering | Year: 2014

Borehole instability during drilling process occurs frequently when drilling through shale formation. When a borehole is drilled in shale formation, the low permeability leads to an undrained loading condition. The pore pressure in the compressed area near the borehole may be higher than the initial pore pressure. However, the excess pore pressure caused by stress concentration was not considered in traditional borehole stability models. In this study, the calculation model of excess pore pressure induced by drilling was obtained with the introduction of Henkel’s excess pore pressure theory Combined with Mohr-Coulumb strength criterion, the calculation model of collapse pressure of shale in undrained condition is obtained. Furthermore, the variation of excess pore pressure and effective stress on the borehole wall is analyzed, and the influence of Skempton’s pore pressure parameter on collapse pressure is also analyzed. The excess pore pressure decreases with the increasing of drilling fluid density; the excess pore pressure and collapse pressure both increase with the increasing of Skempton’s pore pressure parameter. The study results provide a reference for determining drilling fluid density when drilling in shale formation. © 2014 Techno-Press, Ltd. Source

Zhong R.,China University of PetroleumBeijing | Yu X.,China University of PetroleumBeijing | Zou R.,Peking University
Inorganic Chemistry Communications | Year: 2015

A new lanthanide-organic framework formulated as TbL 1 (H3L = 9-(4-carboxy-phenyl)-9H-carbazole-3,6-dicarboxylic acid), was synthesized under hydrothermal reaction condition. Single-crystal X-ray diffraction analysis shows that 1 crystallizes in a hexagonal P65 space group with three-dimensional network and microporous structure. The desolventized framework of 1 shows much higher uptake of CO2 (43.7 cm3 g-1) than that of CH4 (15.1 cm3 g-1) at 1 atm and 273 K, which makes it a potential candidate for CO2/CH4 separation. © 2015 Published by Elsevier B.V. Source

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