With the new method and the travel survey data in Nanhai,Foshan,the paper calculates traveler\'s generalized travel cost and formulates a Logistic-based travel frequency forecasting model.

Structure and the frequency output characteristic of the quartz crystal sensor are described.

The relation equation between the stylus beating frequency and the motion speed of printer head is derived from the analysis of the mechanism of stylus printer and validated by experience.

The results show that the occurrence frequency with force two~four sea conition is 80.

In traditional three-wave-head AC-AC converter,there are deficiencies such as complex control circuit,big harmonic content in output waveform or low output frequency.

Analyse the grain current velocity,dirt percengtage and and temperatures influecing factors for sensor output frequency on the experimental bench.

This paper, with A Catalogue of Foreign Newspapers and Periodicals (ninth edition) as source of materials, makes a deep study of the discipline distribution, country distribution, category distribution, publishing frequency publishing institution, and so on, of biological periodicals, and a brief description of the prominent characteristics of these periodicals.