Chemical oxygen demand (COD) is one of the most important parameters to assess pollution in seawater monitoring, which can be determined accurately by the combined use of UV-Vis spectroscopy and multivariate calibration. The calibration model of COD value was established by partial least squares (PLS). The COD of seawater determined by this method was very close to which determined by the standard method. Compared with the standards, this method has many different advantages, such as high-speed, sensitive, no preprocessing and no secondary pollution.

In this paper, the sol-gel process was used to synthesize a glass binder in thick-film paste for aluminum nitride (AlN) metallization. Some major factors that influenced the sol-gel process including PH value, quantity of water were discussed in detail. The xerogel was analyzed by means of TG-DSC in order to determine its optimum heat treatment process. Meanwhile, the sintering behavior of silver/glass composite thick film had been studied by varying the glass content. The results show that a glass powder of a low melting point and chemically compatible with AlN substrate can be obtained by sol-gel method when the composition (wt %) is CaO (40), B2O3 (15), SiO2 (35), BaO (10). During sintering, the glass becomes liquid and largely affects the microstructure development and square resistance of the thick film. When the glass content is optimum (10wt %), the film adhesion strength achieves maximum and the square resistance has a relatively low value.