Yan Cheng

Rapid Determination of Organic Matter Fractions by Ozonation Chemiluminescence

Understanding marine biogeochemistry requires a network of global ocean in situ monitoring of various parameters on different scales in time and space. Among the various parameters involved in marine biogeochemistry, sediment chemistry is most important, and the organic matter fractions are the dominate factor in this parameter. However, classical methods of determining organic matter fractions consume a great deal of time and labor. In addition, some of these methods can produce high levels of pollution and are therefore not suitable for in situ studies. This study explored a method of rapid determination of organic matter fractions by ozonation chemiluminescence. In this method, the organic matter was separated into extractives, acid soluble fractions and acid insoluble fractions (AIF) using the classical method and then oxidized by ozone. The ozonation chemiluminescence characteristics of eight samples were subsequently used to set up a model to predict the concentrations of organic matter fractions. The model was tested using nine other organic samples and the results showed that it provided a better fit for the predicted acid soluble fractions. This study is the first to demonstrate the use of ozonation chemiluminescence for rapid determination of organic matter fractions; however, further study is required to enable its universal use.

Design of Ocean Surveillance Multifunctional Data Acquisition Processor

It is a very important content for the design and development of automatic ocean surveillance system to make the data acquisition, storage, processing and transmission of ocean surveillance effective. The thesis puts forward a special design method and plan of ocean surveillance multifunctional data acquisition process equipment in detail which provides a great deal of signal patterns such as, analog quantity, digital quantity, pulsed quantity, serial port signal for the ocean surveillance information automatic collection and huge information storage, providing linear communication and remote communication data transmission mode the ocean surveillance tasks probably take application, and also provides the display, analysis, query and processing functions of collected information. The equipment is designed as a simple setup that can be flexibly applied to all kinds of ocean surveillance tasks, which illustrates a good prospect of application and extension

Development and deployment of an autonomous sensor for the in-situ radioactivity measurement in the marine environment

An autonomous sensor for the in-situ radioactivity measurement is developed，based on NaI(Tl) crystal, to detect the activity concentrations of natural and anthropogenic radionuclides in seawater. Its electronics module, integral enclosure and spectrum analysis were presented. The energy, resolution and efficiency were calibrated. Monte Carlo simulation and the minimum detection estimations were realized. The sensor was tested in the water tank and then successfully deployed for the continuous monitoring in the marine environment in Qingdao offshore for the performance test, background measurement and environmental survey. Some results were deduced from the gamma ray spectra and discussed in comparison with those from the laboratory and literatures.