An Siwen – new PhD at STC

Save favourite 14 Mar March 2018

We warmly welcome An Siwen as a new PhD student here at STC! Mid Sweden University is very familiar to An Siwen as she completed her Master's degree in Electronic Design with us a few years ago. Her research will focus on measurement systems for detecting toxic metals in nature and in industry using energy dispersive X-ray fluorescence technique.

The research will contribute to environmental improvements to detect for instance, fly ash and leachate from municipal incineration plants.

But how did An Siwen find itself back to us at Mid Sweden University and STC?
- I really enjoyed my two years here in Sundsvall between 2011 and 2013. It was very rewarding to work in the research group Radiation Sensor Systems. There is a huge difference in the working environment here compared to China. I feel more energetic and free here. I felt that STC would be a great place to pursue my PhD. In addition, the research area is very close to my heart as China, and especially Beijing, has major environmental problems with wastewater and fly ash. This research will have a significant impact on the global environment, An Siwen describes.

During her master's program, An Siwen built a measurement system to measure the characteristic of a silicon detector. After that, she has worked with the temperature dependence and sensitivity profile of a Gallium Arsenide-based semiconductor detector. 

Important research for environmental improvements
An Siwen’s PhD research will focus on environmental measurement systems using energy dispersive X-ray fluorescence. It is a non-destructive way to determine the chemical composition of all kinds of materials, such as solid, fluid, force. For example, this method can be used to detect contaminants in wastewater and drinking water and contaminants in fly ash from municipal solid waste incineration.

- The measurement setup for our research contains an X-ray tube. The tube irradiates a sample and a detector measures the radiation coming from the sample. In this way, we can detect toxic metals such as Chromium, Molybdenum and Cadmium. The goal of my research is to get more knowledge about how we can minimize environmental impact, An Siwen explains.

For the moment, An Siwen collects samples of fly ash and wastewater from a combined heat and power plant (Korstaverket) and the city landfill (Blåbergstippen) run by the partners Sundsvall Energi and Mittsverige Vatten och Avfall. She will start analyzing the presence of toxic metals. An Siwen points out that for an online measurement system on site, it is efficient to take actions before landfill if the metal content in the fly ash is higher than allowed for non-hazardous waste.

From Artificial Intelligence to X-ray technique

From the beginning, it was not decided that An Siwen would focus on X-ray technique. She actually chooses the major Intelligences Science and Technology /Artificial Intelligence for her bachelor at Beijing Information Science and Technology University.

- I thought it seemed fun with AI related to robots, but after my years as an exchange student and my master at Mid Sweden University, I switched area to of X-ray technology instead. The research team has a big part of this as they made the research area so interesting to me. The exciting thing with electronics is that you cannot see what you are measuring by our eyes, but you can measure it with a setup, An Siwen describes.

Before starting her PhD studies, An Siwen worked as a software designer for four years in Beijing, where she focused on the functionality of the software itself.

During her spare time An Siwen likes to play ping-pong and go to the movies. The film selection changes from comedies to drama or “feel good” movies - all depends on what mood she is on.

In the summer, she hopes to get a visit from her parents who are living in Beijing.
- It is better that they visit me in the summer when it is so hot in Beijing. Here is a more comfortable temperature, An Siwen smiles.


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