This paper presents an unsupervised method to identify internet new words from the large scale web corpus, which combines with an improved Point-wise Mutual Information (PMI), PMIk algorithm, and some basic rules. This method can recognize internet new words with length from 2 to n (n is any number as needed). Experimented based on 257 MB Baidu Tieba corpus, the precision of proposed system achieves 97.39% when the parameter value of PMIk algorithm is equal to 10, and the precision increases 28.79%, compared to PMI method. The results show that proposed system is significant and efficient for detecting new word from the large scale web corpus. Compiling the results of new word discovery into user dictionary and then loading the user dictionary into ICTCLAS (Institute of Computing Technology, Chinese Lexical Analysis System), experimented with 10 KB Baidu Tieba corpus, the precision, the recall and F-measure were promoted 7.93%, 3.73% and 5.91% respectively, compared with ICTCLAS. The result show that new word discovery could improve the performance of segmentation for web corpus significantly.

Hydrothermal synthesis of anatase titania nano-powder is a widely used method in the chemical industry and the material sciences. The size of the anomaterial is one of the significant concerns in related researches. Anatase titania with different sizes are synthesized from Ti(SO₄)₂ by adjusting the pH value, the reaction time and the precursors concentrations. The results indicate that the size of nano-titania has an approximately logarithmic relation with the reaction time; the influence of Ti(SO₄)₂ concentration and pH value on the particle size is independent; the synthesis of anatase titania nano-powder with different sizes could be achieved by controlling the synthesis temperature, the precursor concentrations and the pH values.