Y2O3 with particle sizes ranging from 5 nm to 1  μm were studied at high pressure using x-ray diffraction and Raman spectroscopy techniques. Nanometer-sized Y2O3 particles are shown to be more stable than their bulk counterparts, and a grain size-dependent crystalline-amorphous transition was discovered in these materials. High-energy atomic pair distribution function measurements reveal that the amorphization is associated with the breakdown of the long-rang order of the YO6 octahedra, while the nearest-neighbor edge-shared octahedral linkages are preserved.

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Sea cucumbers possess high-value and bioactive components that have been used for human food and pharmaceuticals in treating a wide number of ailments. Most of the sea cucumber products on the market are dehydrated due to the immediate autolysis that occurs upon removal of the sea cucumber from seawater. Rehydration of the dried products is necessary to obtain sea cucumbers with the highest water content. In this study, a rapid and non-invasive NMR and MRI method was introduced to analyze the rehydration process for dried sea cucumber. The spin-spin relaxation time (T 2 ) weighted NMR signal, obtained by a CPMG pulse sequence and processed by the chemometric method, was used to identify lightly dried and salted dried sea cucumber. The water uptake and distribution during the rehydration process was monitored by NMR 1 H T 2 . Structural changes were analyzed by MRI with T 1 and T 2 weighted imaging. The results indicated that the proper presoaking and rehydration time was 24 and 96 h, respectively, for lightly dried sea cucumber. Good linear correlation during the rehydration process was observed between the NMR parameters and texture profile analysis parameters including the hardness, chewiness, and rehydration ratio of lightly dried sea cucumbers. The NMR and MRI method has the potential to noninvasively analyze the rehydration process of dried sea cucumber.

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Yb 3+ /Er 3+ co-doped Zn 2 SiO 4 ceramics are rapidly synthesized by the microwave radiation method. Green and red up-conversion emissions are observed in Zn 2 SiO 4 : Yb 3+ , Er 3+ ceramics under 980 nm excitation. The influence of co-doped Li + or Bi 3+ ion on luminescence intensity for the phosphors has been investigated. At Li + or Bi 3+ doping concentration of 1 mol%, up-converted green emission can be increased by 6 times and 20 times, respectively. It is believed that co-doped Li + or Bi 3+ ion results in the local distortion of Er 3+ in Zn 2 SiO 4 , increasing the intra-4f transitions of Er 3+ ions. The local distortion is proved by spectral probing method with Eu 3+ .

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