Nonlinear instability for nonhomogeneous incompressible viscous fluids

We investigate the nonlinear instability of a smooth steady density profile solution to the three-dimensional nonhomogeneous incompressible Navier-Stokes equations in the presence of a uniform gravitational field, including a Rayleigh-Taylor steady-state solution with heavier density with increasing height (referred to the Rayleigh-Taylor instability). We first analyze the equations obtained from linearization around the steady density profile solution. Then we construct solutions to the linearized problem that grow in time in the Sobolev space H ^k , thus leading to a global instability result for the linearized problem. With the help of the constructed unstable solutions and an existence theorem of classical solutions to the original nonlinear equations, we can then demonstrate the instability of the nonlinear problem in some sense. Our analysis shows that the third component of the velocity already induces the instability, which is different from the previous known results.     

Comparisons of soil pretreatment methods for SF-ICP-MS determination of ultra-trace level plutonium in water soluble and exchangeable fractions

Journal of Radioanalytical and Nuclear Chemistry - In this study, we developed a method to evaluate the potentially bioavailable fraction of Pu in agricultural soils by determining their water...     

Mesoporous Zirconium Phosphonate Hybrid Bentonite as a Novel Efficient Catalyst for the Removal of Trace Olefins from Aromatics

A nove l mesoporous zirconium phosphonate hybrid bentonite (MZrPHB ) catalyst was prepared for the removal of trace olefins from refining aromat ic oil. Pyridine-FTIR, NH₃?TPD, XRD, and N₂ adsorptiondesorption analysis were applied to characterize acidic properties and textural properties of catalysts. And its olefins removal performance of MZrPHB catalyst was evaluated in comparison with commercial clay catalyst. It is found that the MZrPHB catalyst possesses an abundance of weak Lewis acid centers, large surface area, and regular mesopore, and thus, exhibits a longer treat life and higher olefins conversion compared to commercial clay catalyst. MZrPHB prepared in this report can be considered as a promising and superior alternative material to commercial clays for the purification of aromatics.     

A double‐layered zinc(II) coordination polymer with the ligand 3,5‐bis(carboxylatomethoxy)benzoate

In the title compound, poly[hexaaquabis[μ₄‐3,5‐bis(carboxylatomethoxy)benzoato]trizinc(II)], [Zn₃(C₁₁H₇O₈)₂(H₂O)₆]_n, there are two crystallographically distinct Zn^II cations which are bridged by polycarboxylate ligands in a μ₄‐bridging mode. A pair of ligands bridges adjacent Zn atoms to give centrosymmetric dimetal building blocks which act as four‐connected nodes to be further interlinked into a two‐dimensional double‐layered framework with (4,4) topology. Other Zn atoms, lying on inversion centres, occupy the cavities of this topological structure. This submission shows a versatile polycarboxylate ligand with rigid and flexible functional groups, the co‐operation and complementarity of which would meet the coordination requirements of a variety of topological structures.     

两步溶胶-凝胶法于SiO2/聚合物杂化基质中原位合成铕的三元配合物及其发光性质

采用两步溶胶－凝胶过程制备了含铕的三元配合物的凝胶。荧光激发光谱证实于ＳｉＯ２基质中原位合成了铕的配合物。含铕配合物的杂化材料发出铕的特征荧光，与相应的纯配合物溶于乙醇相比，铕离子具有较长的荧光寿命。