Papers by Keyword: Chlorine

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Authors: Wen Jie Zhang, Mei Ling Hu, Jia Wei Bai, Hong Li
Abstract: Photoelectrochemical (PEC) degradation of Procion Red MX-5B was investigated in aqueous NaCl solutions. PEC degradation efficiencies showed strong dependence on the concentrations of aqueous NaCl solutions and applied potentials. 95% decolorization of the dye could be achieved in 10 minutes at applied potential of 8 V in 0.3 M NaCl solution, while the efficiency was only 35% by photocatalytic oxidation. Electrodegradation can be as powerful as PEC degradation upon dye decolorization when the potential exceeds 5 volts. However, it can not mineralize dye degradation intermediates by itself alone. PEC degradation performed very high TOC removal capacity and nearly 80% of total organic carbon was removed in the first hour of reaction, compared with 50% removal in PCO process during the same period.
Authors: Takahisa Ohno, Taizo Sasaki, Akihito Taguchi
Authors: Tomoaki Hatayama, T. Shimizu, Hiroshi Yano, Yukiharu Uraoka, Takashi Fuyuki
Abstract: Anisotropic thermal etching of 4H-SiC {0001} and {11-20} substrates was studied in the mixed gas of chlorine (Cl2) and oxygen (O2) over 900oC. Etch pits appeared only on the (0001) Si face. Etching rates depended on the temperature, O2/Cl2 ratio, and an etching direction on the substrate surfaces. When the mesa structure was formed by the selective etching method, sloped sidewalls were observed around the periphery of the mesa. The angle of sidewalls depended on the orientation of substrates.
Authors: Zhen Li, Li Xia Zhou, Qing Liu
Abstract: The co-pyrolysis process of coal and waste plastics was studied. Changing and transferring property of chlorine in the process was investigated. There was synergistic effect between coal and waste plastics when chlorine was released, which resulted in increase of chlorine in tar and decrease in coke. The effect of waste plastics’ amount on chlorine releasing property varied with the amount of waste plastics in the sample and the time of constant temperature at the same final co-pyrolysis temperature (such as 950 oC). Using the distributional function of chlorine, the distribution of chlorine in coke, tar and gas was studied. The results indicated that the distribution of chlorine in the co-pyrolysis process could be controlled to a certian extent by controlling the percentage of waste plastics and the time of constant temperature. The amount of chlorine redistributed in coke decreases with the increase of constant temperature time and increased with the increase of the percentage of waste plastics. On the contrary, the chlorine in tar increased with the increase of the constant temperature time and the percentage of waste plastics. And the chlorine redistributed in gas increased with the increase of the constant temperature time, but it decreased when the percentage of waste plastics increased. Additionally, the mathematical model of chlorine changing and transferring rule was established.
Authors: Woo Teck Kwon, Soo Ryong Kim, Y. Kim, Jong Hee Hwang, Vikram V. Dabhade, Tae Wook Yoo, Seong Youl Bae
Abstract: The possible utilization of automobile shredder residue as a fuel in the cement kiln process was investigated. The detailed characteristics of the automobile shredder residues were investigated in terms of it’s chlorine content as a fuel feed and its circulation in cement kiln. For estimation of the chlorine content in the cement kiln system, the Weber model which is one of the circulation material’s forecast model was used. From the results, we estimated the chlorine by-pass rate should be 1 ~ 2 percent, for maintaining the present level of chlorine content’s on the hot-meal of the cement kiln system.
Authors: Giovanni Alfieri, Tsunenobu Kimoto
Abstract: An annealing study, in the 100-1400 C temperature range ,was carried out on Cl-implanted n- or p-type 4H-SiC epilayers. The electrical characterization of the epilayers shows the rise of several deep levels and the role of Cl, on both carrier concentration and defects' microscopic structure, is discussed in the light of theoretical results obtained by density functional calculations performed on a 64-atom cubic SiC supercell.
Authors: Hidenori Koketsu, Tomoaki Hatayama, Hiroshi Yano, Takashi Fuyuki
Abstract: The sub-trenches in 4H-SiC Si- and C-faces could be disappeared by the thermal treatment in chlorine ambience at 900-1000oC. The surface morphologies of the thermally treated trench-sidewalls were unchanged. It is considered that the sub-trench is selectively removed because thermally Cl2 etching rate of the (0001) Si- and (000-1) C-face are different to the (11-20) and (1-100).
Authors: Hidenori Koketsu, Tomoaki Hatayama, Kento Amishima, Hiroshi Yano, Takashi Fuyuki
Abstract: The sloped sidewall angle in 4H-SiC mesa structure could be controlled by a thermal etching at 900oC in chlorine (Cl2) based ambience. 4H-SiC C face with 8o off substrate was used. The SiO2 layers for the etching mask were formed by a deposited SiO2 layer or a thermally oxidized layer. Thermal etching was carried out at Cl2 ambience at 900oC for 15 minutes. The surface morphologies of the mesa structures were observed with the scanning electron microscope (SEM) and atomic force microscope (AFM). The sloped angles at the mesa sidewalls using deposited SiO2 mask and thermal SiO2 mask were about 23o and 60o, respectively. These results mean that the angle of sloped sidewall can change by mask fabrication method.
Authors: Tomoaki Hatayama, Hidenori Koketsu, Hiroshi Yano, Takashi Fuyuki
Abstract: Relationship between the chemical reactivity and the orientation of SiC substrates was investigated. Thermal etching of 4H-SiC in the mixed gas of oxygen and chlorine was carried out as the chemical reaction. The etching rate did not change monotonously with the increase of the off angle in 4H-SiC (000-1) C substrate. By the use of such tendency in the thermal etching, the three dimensional structure with the specific pyramidal plane was able to be obtained.
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