Experimental results of helicon sources

Helicon plasma source is known as an efficient generator of uniform and high density plasma. A helicon plasma source was developed for the investigation of plasma striping and plasma lens at the Institute of Modern Physics, CAS. In this paper, the characteristics of helicon plasma have been studied by using Langmuir four-probe and a high plasma density up to 3.9×1013 /cm3 has been achieved with the Nagoya type III antenna. In the experiment, several important phenomena have been found: (1) for a given magnetic induction intensity, the plasma density became greater with the increase of RF power; (2) the helicon mode appeared at the RF power between 300 W and 400 W; (3) the plasma density gradually tended to saturation as the RF power increased to the higher power; (4) a higher plasma density can be obtained by a good matching between the RF power and the magnetic field distribution. The key issue is how to optimize the matching between the RF power and the magnetic field. Moreover, some tests on the extraction of ion beam were performed, and the preliminary results were given. The problems which existed in the helicon ion source will be discussed and the increase in beam density will be expected by extraction system optimum.

Modeling of Hillslope Runoff and Soil Erosion at Rainfall Events Using Cellular Automata Approach

National Science Fund for Distinguished Young Scholars of China [40225004]; National Natural Science Foundation of China [40471048]

Formation and modeling of disinfection by-products in drinking water of six cities in China

Funding and support for this project was provided by NSFC (Grant No. 40771015), and Key International Science and Technology Cooperation Projects (Grant No. 22007DFC20180). The authors also gratefully acknowledge the support of Key Projects in the National Science & Technology Pillar Program in the Eleventh Five-year Plan Period (Grant No. 2006BAD01B06-02). The authors thank the CDCs of Daqing, Beijing, Tianjin, Zhengzhou, Changsha and Shenzhen cities for field and laboratory technical support.

Sulfonated poly(ether ether ketone)/clay-SO3H hybrid proton exchange membranes for direct methanol fuel cells Journal of Power Sources

A new type of sulfonated clay (clay-SO3H) was prepared by the ion exchange method with the sulfanilic acid as the surfactant agent. The grafted amount of sulfanilic acid in clay-SO3H was 51.8 mequiv. (100 g)(-1), which was measured by thermogravimetric analysis (TGA). Sulfonated poly(ether ether ketone) (SPEEK)/clay-SO3H hybrid membranes which composed of SPEEK and different weight contents of clay-SO3H, were prepared by a solution casting and evaporation method. For comparison, the SPEEK/clay hybrid membranes were produced with the same method.

Modeling of organic light-emitting diodes with graded concentration in the emissive multilayer

We model the electrical behavior of organic light-emitting diodes whose emissive multilayer is formed by blends of an electron transporting material, tris-(8-hydroxyquinoline) aluminum (Alq(3)) and a hole transporting material, N,N-'-diphenyl-N,N-'-bis(1,1(')-biphenyl)-4,4-diamine. The multilayer is composed of layers of different concentration. The Alq(3) concentration gradually decreases from the cathode to the anode. We demonstrate that these graded devices have higher efficiency and operate at lower applied voltages than devices whose emissive layer is made of nominally homogeneous blends. Our results show an important advantage of graded devices, namely, the low values of the recombination rate distribution near the cathode and the anode, so that electrode quenching is expected to be significantly suppressed in these devices.