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        검색결과 453

        384.
        1994.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 발표된 (박 1994) 창날개뿔나방과와 속먹이뿔나방과에 이어 한국산 감꼭지나방과 7종(2미기록종), Batrachedridae 1종(신종기) Blastodacnidae 3종(1미록기종)을 정리하였으며, 창날개뿔나방과, 2종을 신종으로 기재함과동시에 2미기록종을 정리발표한다. 기발표된 종들에 대해서는 전체목록을 위해 유충의 기주에 관한 제정보를 추가하여 삽입하였다. 처음 소개되는 상기 2개과의 우리말 이름은 아직 동서학자들간의 분류체계에 관한 이견이 크므로 새로운 분류체계가 정립되는데도 추후에 명명키로한다.
        4,000원
        387.
        1994.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have constructed a 3-dim hydrodynamics code called BTSPH. The fluid dynamics part of the code is based on the smoothed particle hydrodynamics (SPH), and for its Poisson solver the binary tree (BT) scheme is employed. We let the smoothing length in the SPH algorithm vary with space and time, so that resolution of the calculation is considerably enhanced over the version of SPH with fixed smoothing length. The binary tree scheme calculates the gravitational force at a point by collecting the monopole forces from neighboring particles and the multipole forces from aggregates of distant particles. The BTSPH is free from geometric constraints, does not rely on grids, and needs arrays of moderate size. With the code we have run the following set of test calculations: one-dim shock tube, adiabatic collapse of an isothermal cloud, small oscillation of an equilibrium polytrope of index 3/2, and tidal encounter of the polytrope and a point mass perturber. Results of the tests confirmed the code performance.
        5,100원
        392.
        1973.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        1) 쇠파리의 누대 실내사육을 위한 온도는 약 가 좋으며, 이때 유충기간은 약 6.8일, 용기간은 5.3일, 산란전기간은 10.4일, 성충의 수명은 약 30일이었다. 2) 인공사육에 있어서 용화율은 우화율은 였으며 성비는 1 : 1이었다. 3) 용의 체중량은 약 14.5mg이었으며, Wheat bran medium 보다 Standard medium이 사육성적이 좋았다. 4) medium 125gr에 대한 난의 접종수는 약 310개가 가장 적합하였다. 5) rectangular cage를 사용할 경우, 성충의 resting place는 가 적합할 것으로 본다.
        4,000원
        393.
        2020.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        This study investigates the problem of outlier detection based on discrete wavelet transform in the context of time series data where the identification and treatment of outliers constitute an important component. An outlier is defined as a data point that deviates so much from the rest of observations within a data sample. In this work we focus on the application of the traditional method suggested by Tukey (1977) for detecting outliers in the closed price series of the Saudi Arabia stock market (Tadawul) between Oct. 2011 and Dec. 2019. The method is applied to the details obtained from the MODWT (Maximal-Overlap Discrete Wavelet Transform) of the original series. The result show that the suggested methodology was successful in detecting all of the outliers in the series. The findings of this study suggest that we can model and forecast the volatility of returns from the reconstructed series without outliers using GARCH models. The estimated GARCH volatility model was compared to other asymmetric GARCH models using standard forecast error metrics. It is found that the performance of the standard GARCH model were as good as that of the gjrGARCH model over the out-of-sample forecasts for returns among other GARCH specifications.
        394.
        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℃.
        395.
        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.
        396.
        2017.11 서비스 종료(열람 제한)
        Depending on the steam pressure and temperature balance, it is possible to increase the power generation efficiency of the steam turbine by increasing the heat loss of the turbine by increasing the temperature and pressure. As the high temperature and high pressure increase, the boiler main steam amount is reduced by about 10%, but the increase rate of the heat drop is larger than the decrease rate of the steam flow rate, leading to improvement of power generation efficiency. Utilizing the US Department of Energy Steam Turbine Calculator, we calculated the electricity produced by steam temperature and pressure changes. In this study, the steam temperature was increased from 50℃ to 500℃ at the steam temperature of 20 kg/cm²×300℃, and increased by 10 kg/cm² at the pressure of 20 kg/cm² at the pressure of 60 kg/cm² to investigate the changes in electricity production. Electricity production increased with increasing temperature and pressure. The electricity production was increased by 40.11% at 40 kg/cm²×400℃ and 75.56% at 60 kg/cm²×500℃ compared to the standard condition of 20 kg/cm²×300℃ for comparison.
        397.
        2017.11 서비스 종료(열람 제한)
        Energy can be reduced by reducing the exhaust gas temperature at the catalyst inlet and reducing or not using the amount of steam to reheat the exhaust gas. At this time, it is a method to improve the power generation efficiency by using the saved energy for power generation. When the exhaust gas temperature at the inlet of the catalytic reaction tower is operated at about 210℃, it is necessary to increase the temperature of the flue gas downstream of the bag filter at 165℃ to 45℃ to 210℃ required for the catalytic reaction. In the case of low temperature catalyst application, the temperature required for the catalytic reaction tower may be 185℃ and the temperature may be raised only 20℃. Therefore, the amount of steam for heating can be reduced. If the exhaust gas temperature of the bag filter inlet can be increased to 190℃, it can be combined with the low-temperature catalyst to reduce the energy consumed by removing exhaust gas ash. On the other hand, since the high-pressure steam is used as the heat source for reheating the exhaust gas, the reheating temperature is limited. According to such conditions, the exhaust gas temperature at the inlet of the catalytic reaction tower is often designed at about 200 to 220℃.
        398.
        2017.11 서비스 종료(열람 제한)
        Even if the amount of exhaust gas is the same, it is possible to reduce the exhaust gas exit heat at the outlet of the boiler facility by lowering the outlet temperature of the economizer, so that it is possible to increase the heat quantity recovered from the boiler facility. There are many cases where the existing facility adopts 220~250℃ as the design value of the exhaust gas temperature at the exit of the economizer. However, in recent years, there has been a case of cooling and recovering heat to 200℃ or less from the viewpoint of active heat recovery. The amount of combustion exhaust gas is reduced by reducing the amount of combustion air supplied to the incinerator, and the amount of heat exhausted from the boiler facility is reduced, thereby improving the boiler efficiency. The holding energy of the combustion exhaust gas is the product of the exhaust gas amount and the specific heat and the temperature. In order to recover more heat from the combustion exhaust gas, not only the heat loss in the boiler facility is reduced, but also the heat radiated from the boiler facility is reduced. It is effective to reduce the exhaust gas temperature at the outlet of the heat recovery equipment and reduce the amount of exhaust gas in order to reduce the amount of exhaust heat of the exhaust gas. Even if the exhaust gas temperature at the outlet of the economizer is the same, the amount of exhaust gas discharged at the boiler facility outlet is reduced by reducing the amount of exhaust gas, and an increase in the recovered heat quantity at the boiler is expected.
        399.
        2017.11 서비스 종료(열람 제한)
        Persistent organic pollutants are highly toxic, stay in the environment for a long time, accumulate in the body according to the food chain, and cause damage not only to the area where they occur but also to other areas beyond the border. Parties to the Convention, as well as Korea, are obliged to carry out various efforts to control, reduce or eliminate sources of POPs in accordance with the national implementation plan. In addition, national efforts to limit the production, distribution and use of persistent organic pollutants and the current state of domestic pollution and emissions should be submitted every five years. A flame retardant is a polymeric material with a property that is easy to burn, and it lowers the ignition point by adding a compound having a large flame retarding effect such as halogen, phosphorus, and a nitrogen metal compound. Among them, chlorine-based flame retardants classified as halogen-based are used for suppressing ignition of combustible organic materials including plastics, furniture, textiles, clothing, and electronic products. It is also used as an alternative to brominated flame retardants, causing mutations in carcinogenic substances, hormone destruction, and nervous system damage. In the case of waste containing chlorine-based flame retardants in Korea, the methods and standards for disposal of waste are not specified. The highest SCCP values were 4,253.09 mg/kg for polyurethane foam, 628.29 mg/kg for mobile phone case and 341.91 mg/kg for flame retardant rubber sheet. In the case of car seats no SCCPs were detected, and TCEP was detected at 512. 66 mg/kg, exceeding the EU limit of 5 mg/kg. However, other chlorinated flame retardants TDCP and TDCPP were not detected in all samples.
        400.
        2017.11 서비스 종료(열람 제한)
        Annex A and Annex B of the Stockholm Convention define POPs as unintentional releases to Annex C, as well as organochlorine pesticides, polychlorinated biphenyls and hexachlorobenzen which are intentionally produced and used. These pesticides are very stable in the atmosphere due to insecticides, fungicides, herbicides, etc., and are likely to accumulate in living organisms due to residues in crops. There are 15 substances listed in POPs. These materials are widely used due to their high chemical stability, low solubility in water, high volatility, strong insecticidal effect and relatively low production costs. Aldrin-containing pesticides are known to have a combustion method for incineration in a chemical incinerator equipped with a reheat-burner device and a gas scrubber, and a solidification isolation method for solidifying and filling with cement mixed with a combustible material in waste treatment. In the case of solid-phase pesticides, HCB was 421.8 ng/g, Endosolfan-2 73.044 ng/g, PeCB 53.972 ng/g and Endosolfan-1 43.649 ng/g. In the case of liquid pesticides, HCB concentration was the highest at 167.489 ng/g similar to that of the solid phase, followed by PeCB at 23.462 ng/g. B-HCH, g-HCH, d-HCH and the like were detected as a small amount of other substances. It is judged that it is not necessary to set separate operating conditions or preventive facility standards since the material is decomposed sufficiently at 850℃ or more. However, considering the possibility of dioxin or unintentional persistent organic pollutants, it is considered appropriate to operate at above 1,100℃.