• International conference on construction engineering and project management
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• 2013.01a
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• pp.196-203
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• 2013

Environmental problems like global warming have now become important issues that should be considered in all industries, including construction. In South Korea, many studies have been conducted to achieve the government's goals of reduction in environmental impacts. However, the research on buildings has only focused on CO₂ emission as a research target despite the fact that other environmental impacts resulting from ozone depletion and acidification should also be considered, in addition to global warming. In this regard, this study attempted to propose assessment criteria and methods to evaluate the environmental performance of the structures from various aspects. The environmental impact category can be divided into global impacts, regional impacts, and local impacts. First, global impacts include global warming, ozone layer depletion, and abiotic resource depletion, while regional impacts include acidification, eutrophication, and photochemical oxidation. In addition, noise and vibration occurring in the building construction phase are defined as local impacts. The evaluation methods on the eight environmental impacts will be proposed after analyzing existing studies, and the methods representing each environmental load as monetary value will be presented. The methods presented in this study will present benefits that can be obtained through green buildings with a clear quantitative assessment on structures. Ultimately, it is expected that if the effects of green buildings are clearly presented through the findings of this study, the greening of structures will be actively expanded.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.4
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• pp.347-361
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• 2003

Sulfur dioxide (SO$_2$), ozone, total suspended particulates (TSP) and PM$_{2.5}$ were measured at Deokjeok Island in the Yellow Sea during April 1999 to June 2000. Although the emission amount of air pollutants is quite low in this small island of 36 km$^2$ with 1.4 thousand inhabitants, there are pollutant sources such as an oil -firing power plant and a wharf for ferryboat. The island is also influenced from the emissions from the greater Seoul area in the east and from China in the west. In order to characterize the pollutant variations due to interactions between transport and local emissions. the correlation between variations of SO$_2$ and ozone was investigated. Mass and ion concentrations of TSP and PM$_{2.5}$ were examined on selected episode days of positive and negative correlations between the two gaseous species in spring and winter. The effects of transport were pronounced on the days of positive correlation in spring with higher concentrations of ozone and PM$_{2.5}$. TSP concentrations were also high on these days because of high wind speeds. On the days of negative correlation in spring, frequent fog associated with low wind speeds facilitated SO$_2$ oxidation and increased sulfate accompanied with decrease in nitrate in PM$_{2.5}$ and chloride in TSP. This latter phenomena was noticeable since it showed that chemical composition of fine particles could be significantly altered not only during the transport but also by local environment.ronment.

• Bulletin of the Korean Chemical Society
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• v.23 no.9
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• pp.1218-1242
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• 2002

Photochemical reactions of aromatic carbonyl compounds with silyl ketene acetals have been explored. Irradiation of acetonitrile or benzene solutions containing aryl aldehydes or ketones in the presence of silyl ketene acetals is observed to promo te formation of ${\beta}-hydroxyester$, 2,2-dioxyoxetane and 3,3-dioxyoxetane products. The ratios of these photoproducts, which arise by competitive single electron transfer (SET) and classical Paterno-Buchi mechanistic pathways, is found to be dependent on the degree of methyl-substitution on the vinyl moieties of the ketene acetals in a manner which reflects expected alkyl substituent effects on the oxidation potentials of these electron rich donors. An analysis of the product distribution arising by irradiation of a solution containing butyrophenone (6) and the silyl ketene acetal 9, derived from methyl isobutyrate, provides an estimate of the rate constants for the competitive Norrish type Ⅱ, SET and Paterno-Buchi processes occuring. Finally, sequences involving silyl ketene acetal-aryl aldehyde or ketone photoaddition followed by 2,2-dioxyoxetane hydrolysis represent useful procedures for Claisen-condensation type, ${\beta}-hydroxyester$ synthesis.

• Journal of Construction Engineering and Project Management
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• v.3 no.3
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• pp.1-9
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• 2013

Environmental problems like global warming have now become important issues that should be considered in all industries, including construction. In South Korea, many studies have been conducted to achieve the government's goals of reduction in environmental impacts. However, the research on buildings has only focused on CO2 emission as a research target despite the fact that other environmental impacts resulting from ozone depletion and acidification should also be considered, in addition to global warming. In this regard, this study attempted to propose assessment criteria and methods to evaluate the environmental performance of the structures from various aspects. The environmental impact category can be divided into global impacts, regional impacts, and local impacts. First, global impacts include global warming, ozone layer depletion, and abiotic resource depletion, while regional impacts include acidification, eutrophication, and photochemical oxidation. In addition, noise and vibration occurring in the building construction phase are defined as local impacts. The evaluation methods on the eight environmental impacts will be proposed after analyzing existing studies, and the methods representing each environmental load as monetary value will be presented. The methods presented in this study will present benefits that can be obtained through green buildings with a clear quantitative assessment on structures. Ultimately, it is expected that if the effects of green buildings are clearly presented through the findings of this study, the greening of structures will be actively expanded.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.3
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• pp.139-148
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• 2000

A mass balance/photochemical modeling approach was used to evaluate the sea-to-air dimethyl sulfide (DMS) fluxes in tropical regions and part of the Southern Ocean. The flux determinations were based on 10 airborne observations by ACE 1 transit flights (i.e., Flights 4-9 and 29-32). The DMS flux values for the tropical regions ranged from 1.0 to 7.4 $\mu$mole/$m^2$/day with an average estimate of 4.2$\pm$2.3 $\mu$mole/$m^2$/day. The seasonal variations in the DMS flux predicted for the equatorial Pacific Ocean based on atmospheric DMS measurements were not entirely consistent with those derived from seawater DMS measurements were not entirely consistent with those derived from seawater DMS measurements reported in previous literature. Inhomogeneities in the DMS flux field were found to cause significant shifts in the atmospheric DMS levels even in the same sampling location. Accordingly, no definitive statement can be made at this stage regarding systematic differences or agreements in the DMS flux estimates from the two approaches. Moreover, this study strongly suggests that DMS oxidation is the most likely dominant source of SO$_2$in tropical regions, which is also supported by another set of compiled observations. Finally, these SO$_2$observations indicate that, when significant data was available for both the boundary and buffer layers, the vertical SO$_2$gradient between these two zones was primarily negative.

• Rapid Communication in Photoscience
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• v.4 no.2
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• pp.37-40
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• 2015

To examine the photosensitized biomolecules damaging activity, dimethoxyP(V)tetrakis(2-naphthyl)porphyrin (NP) and dimethoxyP(V)tetraphenylporphyrin (PP) were synthesized. The naphthyl moiety of NP hardly deactivated the photoexcited P(V)porphyrin ring in ethanol. In aqueous solution, the naphthyl moiety showed the quenching effect on the photoexcited porphyrin ring, possibly through electron transfer and self-quenching by a molecular association. Binding interaction between human serum albumin (HSA), a water soluble protein, and these porphyrins could be confirmed by the absorption spectral change. The apparent association constant of NP was larger than that of PP. It is explained by that more hydrophobic NP can easily bind into the hydrophobic pockets of HSA. The photoexcited PP effectively induced damage of the tryptophan residue of HSA, through electron transfer-mediated oxidation and singlet oxygen generation. NP also induced HSA damage during photo-irradiation and the contributions of the electron transfer and singlet oxygen mechanisms were speculated. The electron transfer-mediated mechanism to the photosensitized protein damage should be advantageous for photodynamic therapy in hypoxic condition. The quantum yield of the HSA photodamage by PP was significantly larger than that of NP. The quenching effect of the naphthyl moiety is considered to suppress the photosensitized protein damage. In conclusion, the naphthalene substitution to the P(V)porphyrins can enhance the binding interaction with hydrophobic biomacromolecules such as protein, however, this substitution may reduce the photodynamic effect of P(V)porphyrin ring in aqueous media.

• Applied Chemistry for Engineering
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• v.19 no.6
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• pp.624-628
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• 2008

Nitrous oxide ($N_2O$), known as one of the major greenhouse gases, is an important component of the earth's atmosphere, and gives rise to precursor of acid rain and photochemical smog. For the removal of $N_2O$ and other nitrogen oxides, the SCR reaction system with various reductants is widely used. This study is based on the results of experimental and theoretical examinations on the catalytic decomposition of sole nitrous oxide ($N_2O$) and selective catalytic reduction of $N_2O$ with $CH_4$ in the presence of oxygen using mixed metal oxide catalysts obtained from hydrolatcite-type precursors. When $CH_4$ is fed together with a reductant, it affects positively on the $N_2O$ decomposition activity. At an optimum ratio of $CH_4$ to $O_2$ mole ratio, the $N_2O$ conversion activity is enhanced on the SCR reaction with partial oxidation of methane.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.1
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• pp.64-74
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• 2017

In this study, we have analyzed relationship between the measured Water Soluble Organic Carbon (WSOC) concentrations and the estimated aerosol water content of $PM_{10}$ (particulate matter with an aerodynamic diameter of less than or equal to $10{\mu}m$) for the period between September 2006 and August 2007 at Seoul, Korea. Water content of $PM_{10}$ was estimated by using a gas/particle equilibrium model, Simulating composition of Atmospheric Particles at Equilibrium 2 (SCAPE2). The WSOC concentrations showed low correlation with Elemental Carbon (EC), but Water Insoluble Organic Carbon (WISOC) were highly correlated with EC. It seemed that hydrophilic groups were produced by secondary formation rather than primary formation. As with the previous studies, WSOC showed good correlation with secondary ions ($NO_3{^-}$, $SO_4{^{2-}}$, $NH_4{^+}$), especially WSOC was highly correlated with $NO_3{^-}$ that is a secondary ion formed by photochemical oxidation from more local sources than $SO_4{^{2-}}$. No apparent correlation between the measured WSOC and estimated water content was observed. However, WSOC showed good correlation with estimated water content when it was assumed that relative humidity was higher than the deliquescence relative humidity of the system. In conclusion, WSOC is correlated with water content by hygroscopic ions and it is expected that nitrate play an important role among the water content and WSOC.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.1
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• pp.63-71
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• 2006

An automated carbonyl measurement system was constructed. Atmospheric carbonyl compounds were extracted onto DNPH containing collection solution while flowing through a glass coil. Each carbonyl species was separated on a HPLC column and quantified by UV absorption detector. Using this system, carbonyl compounds were continuously measured at the campus of Korea University in Seoul, Korea during June, 2005. Sampling resolution was 30 minutes and the detection limit of HCHO was 0.19 ppbv. Also, $\O_{3}$, it's precursors, and meteorological parameters were measured. The maximum, minimum, average, and median concentrations of HCHO during the whole experiment was 35.8 ppbv, 1.4 ppbv, 11.7 ppbv, and 9.3 ppbv respectively. Formaldehyde showed a distinct diurnal variation with a broad maximum around 13 $\sim$ 15, which was 1 $\sim$ 3 hours ahead of an ozone maximum. During a couple of days, however, HCHO concentrations were kept high through the night or increased concomitantly with NOx in the morning. These results imply that HCHO was mainly produced from the photochemical oxidation of VOCs, but local emission sources couldn't be ruled out. The differences between daily maximum and minimum of $O_{3}$ and HCHO were calculated for 11 days of June, when typical diurnal variations were observed for the two species. A strong positive correlation was found between $\Delta O_{3}$ and $\Delta HCHO$ and the average mole ratio of $\Delta HCHO$ to $\Delta O_{3}$ was 2.6. It indicates that formaldehyde played a key role in $\Delta O_{3}$ production as an indicator species in Metropolitan Seoul during June, 2005.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1479-1484
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• 2010

Photosynthesis uses light energy to drive the oxidation of water at an oxygen-evolving catalytic site within photosystem II (PSII). Chlorophyll binding by the photosystem II subunit S protein, PsbS, was found to be necessary for energy-dependent quenching (qE), the major energy-dependent component of non-photochemical quenching (NPQ) in Arabidopsis thaliana. It is proposed that PsbS acts as a trigger of the conformational change that leads to the establishment of nonphotochemical quenching. However, the exact structure and function of PsbS in PSII are still unknown. Here, we clone and express the recombinant PsbS gene from Arabidopsis thaliana in E. coli and purify the resulting homogeneous protein. We used various biochemical and biophysical techniques to elucidate PsbS structure and function, including circular dichroism (CD), fluorescence, and DSC. The protein shows optimal stability at $4^{\circ}C$ and pH 7.5. The CD spectra of PsbS show that the conformational changes of the protein were strongly dependent on pH conditions. The CD curve for PsbS at pH 10.5 curve had the deepest negative peak and the peak of PsbS at pH 4.5 was the least negative. The fluorescence emission spectrum of the purified PsbS protein was also measured, and the ${\lambda}_{max}$ was found to be at 328 nm. PsbS revealed some structural changes under varying temperature and oxygen gas condition.