The container was supported by an I-shaped supporter through the bottom plate of the oven. The distance between the container and the oven bottom was 40 mm. The other end of the supporter was placed on an electronic balance (Lightever, LBA5200) so as to measure the weight of the samples. Ambient air (temperature be-tween 23 and 25 C, relative humidity between 10% and 20%, dried with desiccant) was introduced byan air compressor (OutStanding,
750-30L), and flowed along the Teflon tube tothe sample container.A mass flow controller (SevenStar, MFC D07-19C) was installed between the air compressor and the container to measure andcontrol the flow rate. Thermal insulated tube and cavity was installed after the sample container, so as to avoid condensation