Returning corn cobs to the field during corn kernel harvesting is an effective way to improve soil properties and increase crop yield. However, seasonally frozen soil seriously hinders the field decomposition process of corn cobs. To explore the decomposition characteristics and promote field decomposition, in this study, the nylon mesh bag method was used to perform field decomposition tests for 150 days. Fiber composition analysis and microstructure observation were carried out. The results showed that the field decomposition of corn cob was influenced by temperature, precipitation, and frozen soil environment. The 150-day cumulative decomposition rates of the pith, woody ring, and glume were 40.0%, 24.2%, and 36.3%, respectively. Caused by the difference in fiber compositions, the decomposition speeds of pith and glume were much higher than that of the woody ring. The complex microstructures of the pith, woody ring, and glume led to differences in the accessibility of cellulose, which indirectly influenced the field decomposition characteristics. The homogeneous sponge-like structure of the pith and glume increased the accessibility of cellulose and ultimately accelerated the field decomposition, while the compact lignocellulosic structure of the woody ring hindered the decomposition process. Compared with corn stalk, corn cob had similar or even better field decomposition characteristics and excellent application prospects.

Silicon nitride whiskers or rod-like crystals have a wide range application due to its excellent mechanical properties and high temperature performance. Two different silicon powders with different size (mesh 200 and mesh 300, respectively) were chosen to prepare rod-like Si₃N₄ crystals by SHS method and the effects of silicon particle size on the morphology of rod-like Si₃N₄ crystals were investigated. The results indicate that rod-like Si₃N₄ crystals could be formed with either kind of silicon powders when no more than 9wt% extra Y₂O₃ was introduced, which could effectively promote the growth of rod-like Si₃N₄ crystals. The residual free silicon was detected when using coarse silicon powders, while the silicon could be reacted completely with nitrogen gas when using fine silicon powders. The morphology of samples with coarse Si powders as starting materials is more uniform and regular than that of fine Si powders samples. Fine silicon powders are not ideal candidates for forming uniform and regular rod-like Si₃N₄ crystals.

ZnO thin films is a kind of very potential semiconductor materials, due to their excellent chemical, electrical and optical properties. The effects of annealing temperature and coating layers on properties of ZnO thin films prepared by sol-gel immerse technique is studied in this work. The structure properties and optical properties were investigated by XRD, SEM and UV-Vis spectrophotometry respectively. It is found that the thin films were composed of better hexagonal wurtzite crystals with the c-axis preferred orientation by thermal annealing 550°C. With coating layers increasing from 2 layers to 8 layers, the intensity for all diffraction peaks were increased gradually, and the crystallite size of ZnO thin films is slightly increased. The transmittance of prepared thin films is over 80% in the visible-near IR region from 460 nm - 800 nm.