In this study, ELF-MF levels of subway trains were measured to understand the status of the intensity of ELFMF. The measurement points for the train are selected in the center of each train compartment(pantagraph compartment, motor-driven compartment and the compartment that is not connected to any other electric equipment) using EMDEX II. ELF-MF levels of trains were measured from the starting to the terminal station in each lines(Seoul line 1-9, Incheon line 1, Incheon international airport line, Gyungui line, Bundang line, Gyeongchun line, Joongang line, Suin line). We found that the mean and range of ELF-MF levels in the DC power subway train are 2.4 and 0.1~125.9 mG, respectively, while the mean and range of ELF-MF levels in the AC power subway train are 10.4and 0.0~156.3 mG, respectively. Furthermore, the maximum ELF-MF level(156.3 mG) was lower than the reference level(ICNIRP 833 mG, 60Hz). The findings of this study in relation to the characteristics of ELF-MF for subway will be useful to derive the ELF-MF exposure coefficient from our living environment in a subsequent study.

Cathode materials and their precursors are prepared with transition metal solutions recycled from the thewaste lithium-ion batteries containing NCM (nickel-cobalt-manganese) cathodes by a H2 and C-reduction process. Therecycled transition metal sulfate solutions are used in a co-precipitation process in a CSTR reactor to obtain the tran-sition metal hydroxide. The NCM cathode materials (Ni:Mn:Co=5:3:2) are prepared from the transition metal hydroxideby calcining with lithium carbonate. X-ray diffraction and scanning electron microscopy analyses show that the cathodematerial has a layered structure and particle size of about 10 µm. The cathode materials also exhibited a capacity ofabout 160 mAh/g with a retention rate of 93~96% after 100 cycles.

The light trespass problem still has not been solved for a long time because of the complex influences of the reflection or overlap lights. To solve the light trespass problem, the assessment of the characteristics of the spilt light carry out firstly. In this study, we estimated the light trespass reducing performance of various load lightings using by RELUX lighting simulation program. In the simulation program, we designed the lighting environment according to the streetlight installation guideline by the ministry of land, transport and maritime affairs. And we estimated the light trespass caused by roadway lighting from first floor position to fourth floor position. And we compare the light trespass caused by back light of the roadway lighting with the light trespass caused by forward light. Then we estimated the effect of light trespass by improving the light distribution of roadway lighting from Backlight rating 3 to Backlight rating zero. From the research, we find that the light trespass caused by roadway lighting maximize at the first floor position of the house. And the light trespass contribution rate by backlight and forward light is 66 percentage and 33 percentage respectively. And we estimated that the light trespass can be decreased about 40 % by improving the backlight. The result derived from this research will be helpful to establish the light pollution reduction plan to minimize the adverse effect by the spilt light from the roadway lighting.