Guiying Zhang

Preliminary study on air pollution source identification in Xinzhen, Beijing, using NAA and PIXE

A total of 178 aerosol samples in two size fractions, PM10-2.5 (coarse) and PM2.5 (fine), were collected on nucleopore films using a Gent stacked filter unit sampler at the Graduate School of China Nuclear Industrial Group during May 2007 to November of 2009. Black carbon was determined by a reflectometer. A total of 16 elements, Mg, Al, S, Si, P, Cl, Ca, K, Ti, Mn, Fe, Ni, Cu, Zn, As and Pb, were determined by Particle Induced X-ray Emission. Mg, Al, Ca, K and Mn were also determined by Neutron Activation Analysis. Concentrations of all these elements were used to identify possible pollution sources and directions of the airborne particulate matter by means of softwares PMF and CPF. Some extraordinary events, such as sandstorms, firework and transboundary fire smoke were pinpointed by a combination of time series of multielement, relevant meteorological data and softwares Wind rose, Hysplit, and Google earth.

Source apportionment of PM2.5 in Beijing using positive matrix factorization

Abstract In order to do source apportionment of PM2.5 and source trajectories, particle induced X-ray emission and energy disperse-X ray fluorescence were used to analyze chemical composition of samples. Five major sources have been identified by using positive matrix factorization. Source trajectories have been determined by conditional probability function and the potential source contribution function. Extreme events, such as sandstorms, have been identified and traced.

Study on bubble detectors used as personal neutron dosimeters.

Neutron bubble detector is so far the only personal neutron dosimeter satisfying the energy response criteria of the International Committee of Radiation Protection 60 (ICRP 60). This paper presents our studies on neutron bubble detectors including the manufacture, the relevant equipments, the basic calibrations and on-site tests for monitoring personal neutron dose. The results of calibrations show that the highest sensitivity so far manufactured by the authors reaches about 4bubbles/μSv, the correlation coefficient of dose response is 0.99, and the in-batch consistency and reproducibility are up to the ISO standards. The results of on-site test show that the in-batch consistency and between-batch consistency are within 15% relative standard uncertainty. The results are directly readable. The detectors are portable, especially suitable for on-site neutron dose monitoring in n-γ mixed radiation fields.

Delayed neutron counting at CIAE

The facility for delayed neutron counting was built at the China Institute of Atomic Energy in the 1980s. A method of normalized decaying curve of delayed neutron is proposed in this work. Preliminary experiments show that this method is suitable for the determinations of uranium in samples with a wide range of uranium concentrations.

Nuclear fuel cycle modelling using MESSAGE

In order to demonstrate the possibilities of application of MESSAGE tool for the modelling of a Nuclear Energy System at the national level, one of the possible open nuclear fuel cycle options based on thermal reactors has been modelled using MESSAGE. The steps of the front-end and back-end of nuclear fuel cycle and nuclear reactor operation are described. The optimal structure for Nuclear Power Development and optimal schedule for introducing various reactor technologies and fuel cycle options; infrastructure facilities, nuclear material flows and waste, investments and other costs are demonstrated.