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        검색결과 27

        15.
        2018.05 서비스 종료(열람 제한)
        The Stockholm Convention was adopted in Sweden in 2001 to protect human health and the environment, including Persistent Organic Pollutants Rotors, such as toxic and bioaccumulative. Currently, there are 28 kinds of materials. This prohibits and limits the production, use, and manufacture of the product. Korea is a party to the Convention and it is necessary to prepare management and treatment plan to cope with POPs trends. In the text, we have discussed HCBD materials. HCBD belongs to halogenated aliphatic unsaturated hydrocarbons. It is a toxic, organic mixture of bioaccumulation. A study on the treatment of waste containing HCBD substance, We decided to treat the waste containing HCBD thermally. So six samples were selected. Waste water treatment sludge, rubber plate, insecticide, tarpaulin, tire rubber, mixed sample. The tire rubber injected HCBD as a technical sample. HCBD analysis showed that 59.345 ~ 18,238.355 ug/kg was detected. For the thermal treatment, we analyzed element. As a result of thermogravimetric analysis, the weight change due to the decomposition of the material started at 200℃. The material decomposition was completed within 800℃. The thermal treatment was performed on a Lab-scale (1kg/hr). After exhaust gas analysis result, HCBD was detected at 0.01 to 0.09 ug/kg. The decomposition rate is estimated to be 99.848 ~ 99.999%. As a result of dioxin analysis in the exhaust gas, the highest concentration was found in the tarpaulins and the emission limit was exceeded. The concentrations of Cd, Pb, Cr, Cu, Ni and Zn in the residues were very low. Considering the decomposition rate of HCBD containing wastes, incineration treatment at 2 ton/hr or more is considered to be possible. And unintentional persistent organic pollutants such as dioxins in the exhaust gas. Therefore, it is considered safe to operate the incineration temperature at more than 1100℃.
        16.
        2018.05 서비스 종료(열람 제한)
        To achieve energy efficiency improvement is used to lower temperature for emission gas at catalyst inlet, or to reduce/stop using steam to reheat emission gas. Saved energy from this process can be used as power source in order to increase generation efficiency. Dry emission gas treatment, on the other hand, is the technology to increase generation efficiency by using highly efficient desalination materials including highly-responsive slaked lime and sodium type chemicals in order to comply with air pollution standards and reduce used steam volume for reheating emission gas. If dry emission gas is available, reheating is possible only with the temperature of 45℃ in order to expect generation efficiency by reducing steam volume for reheating. Retention energy of emission gas from combustion is calculated by emission gas multiplied by specific heat and temperature. In order to obtain more heat recovery from combustion emission gas, it is necessary to reduce not only exothermic loss from boiler facilities but emission calorie of emission gas coming out of boiler facilities. In order to reduce emission calorie of emission gas, it is efficient to realize temperature lowering for the emission gas temperature from the exit of heat recovery facility and reduce emission gas volume. When applying low temperature catalysts, the energy saving features from 0.03% to 2.52% (average 1.28%). When increasing the excess air ratio to 2.0, generation efficiency decreases by 0.41%. When the inlet temperature of the catalyst bed was changed from 210℃ to 180℃, greenhouse gas reduction results were 47.4, 94.8, 118.5, 142.2 thousand tons-CO2/y, CH4 was calculated to be 550.0, 1100.1, 1375.1, 1650.1 kg-CH4/y, and N2O was 275.0, 550.0, 687.6, 825.1 kg-N2O/y. In the case of high efficiency dry flue gas treatment, reduction of greenhouse gases by the change of temperature 120~160℃ and exhaust gas 5,000 ~ 6,500 ㎥/ton is possible with a minimum of 355,461 ton/y of CO2 and minimum 4,125 tons of CH4/y to a maximum of 6,325 ton/y and N2O to a minimum of 2,045 kg/y to a maximum of 3,135 kg/y.
        17.
        2003.09 서비스 종료(열람 제한)
        DNA methylation is involved in epigenetic processes such as X-chromosome inactivation, imprinting and silencing of transposons. DNA methylation is a highly plastic and critical component of mammalian development The DNA methyltransferases (Dnmts) are responsible for the generation of genomic methylation patterns, which lead to transcriptional silencing. The maintenance DNA methyltransferase enzyme, Dnmt 1, and the de novo methyltransferase, Dnmt3a and Dnmt3b, are indispensable for development because mice homozygous for the targeted disruption of any of these genes are not viable. The occurrence of DNA methylation is not random, and it can result in gene silencing The mechanisms underlying these processes are poorly understood. It is well established that DNA methylation and histone deacetylation operate along a common mechanistic pathway to repress transcription through the action of methyl-binding domain proteins (MBDs), which are components of, or recruit, histone deacetylase (HDAC) complexes to methylated DNA. As a basis for future studies on the role of the DNA-methyl-transferase in porcine development, we have isolated and characterized a partial cDNA coding for the porcine Dnmt1. Total RNA of testis, lung and ovary was isolated with TRlzol according to the manufacture's specifications. 5 ug of total RNA was reverse transcribed with Super Script II in the presence of porcine Dnmt 1 specific primers. Standard PCRs were performed in a total volume of 50 ul with cDNA as template. Two DNA fragmenets in different position were produced about 700bp, 1500bp and were cloned into pCR II-TOPO according to the manufacture's specification. Assembly of all sequences resulted in a cDNA from 158bp of 5'to 4861bp of 3'compare with the known human maintenance methyltransferase. Now, we are cloning the unknown Dnmt 1 region by 5'-RACE method and expression of Dnmt 1 in tissues from adult porcine animals.
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