• 한국환경복원기술학회지
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• 제6권2호
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• pp.27-38
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• 2003

This study aimed to provide basic data for future management of roadside trees by analyzing problems associated with plantation and management of roadside trees through categorization of functions and organizational structure, plantation and management, and management regulations and generating improvement opportunities based on the result of a survey on the awareness of government officials who are directly in charge of managing roadside trees in 31 cities & counties within Kyonggi province. The summary of key results of this study is as follows. First, "roadside tree-related function" is still not considered to be independent. About a half of government officials in charge did not majored in this field and they spent only about "2.09hours", in average, in the roadside tree-related function out of 8 working hours per day. Second, regarding problems and improvement opportunities in roadside tree-related function, lack of time was considered to be the biggest problem in overall management of roadside trees. As for improvement opportunities, "increase of dedicated manpower" and "system development" to facilitate efficient processing were suggested. Third, an annual budget for roadside tree-related affairs was merely 92 million won per city/county. A registry for management of roadside trees was kept manually. As for the roles of roadside trees, improvement of landscape and securing of green area itself were valued highly. Fourth, Ginkgo biloba, Zelkova serrata, and Prunus yedoensis were suggested to be the most appropriate species for roadside tree and Platanus occidentalis, Populus albaglandulosa, Populus euramericana, and Robinia pseudo-acacia were mentioned to be the least appropriate species.

• 환경위생공학
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• 제13권3호
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• pp.79-84
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• 1998

The study result on the domestic waste occurrence and admistration condition of Iksan City as follows ; 1. The year of 1995 has observed a radically decreasing ratio of per capita waste generation compared to the previous year by 26.2%, owing to the publication of the new amendment of volume based charge as well as to the rural population included through the merger of Iksan City and Iksan Country ; the daily quantity of domestic waste for Iksan residents in 1997 was calculated to be $0.66kg/capita{\cdot}day$. 2. Waste generation in nonresidential areas were $8.04kg/capita{\cdot}day$ in average ; the quantity per capita in market places was observed to generate the largest, $36.76kg/capita{\cdot}day$, while that of services was the smallest $0.25kg/capita{\cdot}day$. 3. The average generation per capita of household waste was $0.23kg/capita{\cdot}day$ in the area which has no volume based charge system. This area showed no difference from those of other areas ; the apparent density of the waste recorded the lowest $0.llkg/{\ell}$ for District Offices, while the highest among the classified fields was $0.40kg/{\ell}$ of the Fire Station. 4. Iksan City showed great contribution by decreasing the absolute quantity of waste for landfill by waste classfication, according to the days of the week and reutilizing recyclable waste since August, 1997. 5. Location of a landfill site for disposal of nonrecyclable waste will cause a serious problem to the community and it will be highly recommendable to have governmental support and professtional consultation as well as open discussions, such as hearings, for the settlement of the problem.

• 한국토양비료학회지
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• 제49권5호
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• pp.429-433
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• 2016

Adsorption and precipitation of cadmium (Cd) could be dependent on rate of P addition and Cd level in soil. Therefore, the objective of this study was to examine how addition rate of P affect mechanisms of Cd immobilization such as adsorption and precipitation in different levels of Cd in soil. Arable soils were spiked with inorganic Cd ($CdCl_2$) to give a total Cd concentration of 10, 100, and $1,000mg\;Cd\;kg^{-1}$. Monopotassium phosphate ($KH_2PO_4$, MPP) was selected as phosphate material and mixed with the pretreated arable soil at the rates of 0, 800, 1,600 and $3,200mg\;P\;kg^{-1}$. The mixture soils were incubated at $25^{\circ}C$ for 8 weeks in dark condition. Soil pH decreased with increasing MPP addition rate in all levels of Cd but negative charge of soil increased, thereby reducing 1 M $NH_4OAc$ extractable Cd. Soil solutions were undersaturated with respect to $CdCO_3$ and $Cd_3(PO_4)_2$ with all P addition rate in soil with low Cd level (${\leq}100mg\;Cd\;kg^{-1}$) but supersaturated in soil with high Cd level ($1,000mg\;Cd\;kg^{-1}$). From the above results, Cd solubility was controlled by precipitation of Cd minerals such as $CdCO_3$ and $Cd_3(PO_4)_2$ in soil with high Cd level but by Cd adsorption induced by increase in negative charge of soil with low level of Cd.

• 한국안전학회지
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• 제24권4호
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• pp.90-95
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• 2009

The purpose of this study is to investigate industrial safety and health experts' opinions on the examination system of WMSDs(work related musculoskeletal disorders) risk factors. For doing this, a questionnaire study and two FGIs(focused group interview) were conducted. A questionnaire with open questions about the examination system was developed, and sent to 42 experts consented bye-mail. Of the experts, 24 experts responded, whose data were used in the analysis. The FGIs were performed for the persons in charge of industrial safety and health in industries and ergonomists. The questionnaire study revealed that most experts(91.3%) agreed with legalization of employers' duty for preventing WMSDs, necessity of the 11 tasks designated by Ministry of Labor, the examination system and ergonomics program, and pertinency for the examination system classification of periodic and occasional one. However, more than half experts disagreed with timeliness and appropriateness of the legal system. This was validated by the low approval rates for appropriateness of the 11 tasks, methods of the examination, charge person in the examination and ergonomics program. FGIs showed that it was desirable for the examination system to be legalized, and that the system was generally properly performed. It was suggested that the system be partially revised with reflecting problems disclosed during its enforcement rather than whole revision. It is expected that when revising relevant legal system, the results of this study would be used as valuable data.

• 한국지반환경공학회 논문집
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• 제25권7호
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• pp.5-19
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• 2024

During the blasting process, a fracture zone is formed in the vicinity of the blast hole. Any damage that extends beyond the excavation boundary line necessitates the implementation of an additional support system to assure safety. Typically, fracture zone radius is estimated from blast hole pressure using theoretical methods due to its simplicity. However, linear charge concentration (kg/m) is used for tunnel blasting. This paper compiles Swedish experimental datasets to estimate the radius of fracture zones based on linear charge concentration. Further numerical analyses are performed in LS-DYNA for coupled single-hole blasting. The Riedel-Hiermaier-Thoma (RHT) model has been selected as the constitutive model for this investigation. The numerical model is validated against small-scale laboratory tests. Parametric studies are conducted to predict fracture zones in granite and sandstone rocks using two kinds of explosives, PETN and AFNO. The analyses evaluate ten types of blast hole sizes, ranging from 17 to 100 mm. The results indicate that granite has a larger fracture zone than sandstone, and the PETN explosive predicts more damage than ANFO. Smaller blast holes exhibit smaller fracture zones in comparison to larger blast holes. Wave propagation is more rapidly attenuated in granite than in sandstone. Subsequently, the predicted fracture zone outcomes are compared with the empirical dataset. Fracture zones of medium blast hole diameter align well with the experimental data set. A predictive equation is derived from the data set, which may be used to evaluate blast design to manage fracture zones beyond the excavation line.

• 전기화학회지
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• 제3권2호
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• pp.76-80
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• 2000

Electrochemical oxidation of ethanol has been studied at nickel and $RuO_2-modified$ nickel electrodes in 1 M KOH using electrochemical impedance spectroscopy. Equivalent circuits have been worked out from simulation of impedance data to model oxidation of ethanol as well as the passivation of the electrode. The charge-transfer resistances for oxidation of these electrodes became smaller in the presence of ethanol than in its absence. The nickel substrate facilitated ethanol oxidation at $RuO_2-modified$ nickel electrodes. We also describe the Performance of nanosized electrocatalysts of the same composition in comparison to those of the bulk electrodes. The nanosized electrodes were obtained by electrode-positing the alloy from complexed form of these metal ions with fourth and fifth generation polyamidoamine dendrimers.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.147-152
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• 2004

Aerobic cometabolism of cis-1,2-dichloroethylene (c-DCE) and c-DCE epoxide by a butane-grown mixed culture was evaluated. Transformation of c-DCE resulted in the concomitant generation of c-DCE epoxide. Chloride release studies showed nearly complete oxidative dechlorination of c-DCE (approximately 75%). Mass spectrometry confirmed tile presence of a compound with mass-to-charge-fragment ratios of 112, 83, 48, and 35. The values are in agreement with the spectra of a chemically synthesized c-DCE epoxide. Some evidences indicating the involvement of the monooxygenase in the transformation of c-DCE epoxide are: 1) $O_2$ requirement for c-DCE transformation and butane degradation; 2) butane inhibition on c-DCE transformation and vice versa; 3) the inactivation of c-DCE and c-DCE epoxide transformations by acetylene (a known monooxygenase inactivator); and 4) tire inhibition of c-DCE epoxide transformation by c-DCE.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2011년도 제44차 학술발표회
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• pp.62-62
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• 2011

Intramolecular charge transfer (ICT) system has received great attentions due to their promising optoelectronic properties For the efficient ICT of the chromophore, their organic compound mainly consists of strong electron donors (e.g. $NR_2$ or OR groups) and acceptors (e.g. CN or $NO_2$ groups). According to the molecular design and synthesis, the ICT compounds can be extended in many application fields. In this study, we have synthesized ICT compounds having a strong electron acceptor and donor. These novel ICT compounds were easily synthesized by a previously described method with some modifications. Their single crystals were grown and their structures were solved and described in this presentation.

• Environmental Engineering Research
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• 제10권4호
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• pp.155-164
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• 2005

This study investigated the possibility of reducing the residual aluminum (Al) in the treated water using polymers. Two raw waters (lake and river water) and three kinds of polymers (coagulant, flocculant, and filtration aids) were used for this purpose. This study found that coagulation at the high dose did not necessarily lead to the high concentration of the residual Al in the treated water. The coagulation efficacy was found more important in determining the residual Al than the coagulant dose. The use of a polymer enhanced the removal of turbidity as well as the residual Al. The coagulant aid removed the dissolved Al as well as the particulate Al by helping the coagulation and the solid-liquid separation. The flocculant aid and the filtration aid preferentially removed the particulate Al while helping the solid-liquid separation. The filtration aid reduced the residual Al substantially more effectively than the flocculant aid. The polyamine-based coagulant aid (FL) showed the better performance in reducing the residual Al and turbidity than DADMAC (WT). The cationic flocculant aid with weak charge density and the medium molecular weight (SC-020) showed the best performance in reducing the residual Al.

• 환경위생공학
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• 제14권2호
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• pp.96-104
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• 1999

A questionary survey was conducted to investigate citizen's attitude to the treatment of food wastes in Miryang city. In this study, collection effectives was 87.8%, as 281 individuals among 320 individuals. After volume-base charge system, 86.8% of answers perform source separation and 60.9% of respondents separate everything of recycle goods. The majority of respondents discharge food waste using standard envelope. The biggest problems for deposition of the food wastes are offensive odor and worm for reasons of sanitation. Almost citizens think that the period of deposition suit from two days to three days. More than 90.0% of the citizens recognized that compost products made from food wastes and recognition of the people for the composting and composting facilities was affirmative. Majority of the respondents thought that the administration and the provincial government need activity publicity for the source separation fixations of the food wastes.