Three new water-stable In(III)-based metal-organic frameworks, namely, [In(TTTA)(OH)(HO)]·(DMA) (BUT-70, DMA = N,N-dimethylacetamide), [In(TTTA)(CHO)] (BUT-70A), and [In(TTTA)(OH)] (BUT-70B), with rod-shaped secondary building units (SBUs) and an new acrylate-based ligand, (2E,2'E,2″E)-3,3',3″-(2,4,6-trimethylbenzene-1,3,5-triyl)-triacrylate (TTTA) were obtained and structurally characterized. BUT-70A and -70B were generated in a single-crystal to single-crystal transformation fashion from BUT-70 through guest exchange followed by their removal. The solvents used for guest exchange were methanol and dichloromethane, respectively. Single-crystal structure analyses show that the guest exchange and removal process is accompanied by the substitution of coordinated water molecules of In(III) centers with uncoordinated carboxylate O atoms of TTTA ligands. Moreover, hydroxyl groups bridging two In(III) centers are also replaced by methoxyl groups in the transformation from BUT-70 to -70A. Overall, three metal-organic frameworks (MOFs) are constructed by infinite chains consisting of corner-sharing InO(OR) (R = H or Me) octahedral entities, which are interconnected by TTTA ligands to form three-dimensional frameworks. Unlike most reported MOFs with infinite chains as SBUs, such as well-known MIL-53 and M-MOF-74, which have one-dimensional channels along the chain direction, the BUT-70 series contain two-dimensional intersecting channels. The Brunauer-Emmett-Teller surface area and pore volume of BUT-70A were estimated to be 460 m g and 0.18 cm g, respectively, which are obviously lower than those of BUT-70B (695 m g and 0.29 cm g). Gas adsorption experiments demonstrated that BUT-70A and -70B are able to selectively adsorb CH over CO and CH. At 1 atm and 298 K, BUT-70A uptakes 3.1 mmol g CH, which is 3.6 times that of the CO uptake and 7.2 times that of the CH uptake. Compared with BUT-70A, BUT-70B presents an even higher CH uptake of 3.9 mmol g at the same conditions, but slightly lower Ideal Adsorbed Solution Theory CH/CO and CH/CH selectivities.

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Flexible photonic crystals are attractive devices owing to their multifold tunable parameters additionally introduced by soft substrates or by nanostructured, nano-doped, or nano-embedded soft matters. This not only extends significantly the intrinsic functions of photonic crystals, but also facilitates easy integration of the photonic crystal device into various optoelectronic and sensing systems. So far, flexible metallic photonic structures have been constructed on micrometer scales with complex fabrication procedures. Much simpler and more reproducible methods are expected to achieve such metamaterials in large scales and at low costs. In address to these challenges, we developed a straightforward approach to create soft plasmonic photonic crystals consisting of gold nanolines arranged on stretchable substrates with nanoscale periods, centimeter-scale areas, and high reproducibility using annealed gold nanoparticle colloids.

For the purpose of researching the freezing-thawing cycle physical mechanics properties of sandstone in various chemical solutions, taking the red sandstones from Shandong as the example, freezing-thawing cycles experiments under the condition of H2SO4solution (pH≈1.5), NaOH solution (pH≈12.5), NaCl solution (pH≈7, mass fraction is 4%) and water were conducted. The nuclear magnetic resonance (NMR) technique was used to test the porosity of rock samples after freezing-thawing cycles. Brazilian splitting test was also conducted to test the samples with different times of freezing-thawing cycles and soaking solutions. Results show that the quality change of samples in various solutions is different. The mass of sample in water increased, however, the mass change of the sample in other three solutions showed a firstly increasing and then decreasing tendency. The porosity distribution in rock changed obviously after different time’s freezing-thawing cycles. After 30 times freezing-thawing cycles, the porosity in H2SO4solution, NaOH solution, NaCl solution and water has increased by 151.1%, 85.443%, 39.388%, and 17.976% respectively. With the increase of freezing-thawing cycle’s times, tensile strength of the rock reduced, but the damage properties were different in various solutions. The research can provide some mechanical parameters basis to physical mechanics properties of sandstones.

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