• The Korean Journal of Nuclear Medicine
• /
• v.34 no.3
• /
• pp.183-198
• /
• 2000

Purpose: The purpose of this study was to evaluate alterations of regional cerebral blood flow (CBF) and cerebrovascular reserve (CVR), and correlation between these alternations and cognitive dysfunction in patients with chronic traumatic brain injury (TBI) and normal brain MRI findings. Materials and Methods: Thirty TBI patients and 19 healthy volunteers underwent rest/acetazolamide brain SPECT using Tc-99m HMPAO. Korean-Wechsler Adult Intelligence scale test was also performed in the patient group. Statistical analysis was performed with statistical parametric mapping software (SPM'97) Results: CBF was diminished in the left hemisphere including Wernicke's area in all patients with lower verbal scale scores. In addition, a reduction in CBF in the right frontal, temporal and parietal cortices was related with depressed scores in information, digital span, arithmetic and similarities. In patients with lower performance scale scores, CBF was mainly diminished in the right hemisphere including superior temporal and supramarginal gyri, premotor, primary somatomotor and a part of prefrontal cortices, left frontal lobe and supramarginal gyrus. CVR was diminished in sixty-four Brodmann's areas compared to control. A reduction in CVR was demonstrated bilaterally in the frontal and temporal lobes in patients with lower scores in both verbal and performance tests, and in addition, both inferior parietal and occipital lobes in information subset. Conclusion: Alterations of CBF and CVR were demonstrated in the symptomatic TBI patients with normal MRI finding. These alterations were correlated with the change of intelligence, of which the complex functions are subserved by multiple interconnected cortical structures.

• Radiation Oncology Journal
• /
• v.27 no.3
• /
• pp.111-119
• /
• 2009

Purpose: This study aimed at assessing the value of fluorine-18 fluorodeoxyglucose positron emission tomography ($^{18}F$-FDG PET) for predicting the response of locally advanced rectal cancer to neoadjuvant CRT. Materials and Methods: Between August 2006 and January 2008, we prospectively enrolled 20 patients with locally advanced rectal cancer and who were treated with neoadjuvant CRT at the Korea Institute of Radiological and Medical Sciences. The treatment consisted of radiation therapy and chemotherapy, and this was followed by curative resection 6 weeks later. All the patients underwent $^{18}F$-FDG PET/CT both before CRT and 6 weeks after completing CRT. The measurements of the FDG uptake ($SUV_{max}$), the absolute difference (${\Delta}SUV_{max}$) and the percent $SUV_{max}$ difference (response index, $RI_{SUV}$) between the pre- and post-CRT $^{18}F$-FDG PET/CT scans were assessed. The measurements of the metabolic volume, the absolute difference (${\Delta}$metabolic volume) and the percent metabolic volume difference (response index, $RI_{metabolic\;volume}$) were also assessed. Results: Of the 20 patients who underwent surgery, 11 patients (55%) were classified as responders according to Dworak's classification. The post-CRT $SUV_{max}$ was significantly lower than the pre-CRT $SUV_{max}$. However, there were no significant differences in the $SUV_{max}$ and the metabolic volume reduction between the responders and non-responders. We used a minimum $SUV_{max}$ reduction of 67% as the cut-off value for defining a response, with a sensitivity of 45.5%, a specificity of 88.9%, a positive predictive value of 77% and a negative predictive value of 53.8%. Conclusion: Although there were no statistically significant results in this study, other studies have revealed that $^{18}F$-FDG PET/CT has the potential to assess the tumor response to neoadjuvant CRT in patients with locally advanced rectal cancer.

• Clean Technology
• /
• v.24 no.2
• /
• pp.127-134
• /
• 2018

To reduce the environmental pollution by $NO_x$ from ship engine, International maritime organization (IMO) announced Tier III regulation, which is the emmision regulation of ship's exhaust gas in Emission control area (ECA). Selective catalytic reduction (SCR) process is the most commercial $De-NO_x$ system in order to meet the requirement of Tier III regulation. In generally, commercial ceramic honeycomb SCR catalyst has been installed in SCR reactor inside marine vessel engine. However, the ceramic honeycomb SCR catalyst has some serious issues such as low strength and easy destroution at high velocity of exhaust gas from the marine engine. For these reasons, we design to metallic structured catalyst in order to compensate the defects of the ceramic honeycomb catalyst for applying marine SCR system. Especially, metallic structured catalyst has many advantages such as robustness, compactness, lightness, and high thermal conductivity etc. In this study, in order to support catalyst on metal substrate, coating slurry is prepared by changing binder. we successfully fabricate the metallic structured catalyst with strong adhesion by coating, drying, and calcination process. And we carry out the SCR performance and durability such as sonication and dropping test for the prepared samples. The MFC01 shows above 95% of $NO_x$ conversion and much more robust and more stable compared to the commercial honeycomb catalyst. Based on the evaluation of characterization and performance test, we confirm that the proposed metallic structured catalyst in this study has high efficient and durability. Therefore, we suggest that the metallic structured catalyst may be a good alternative as a new type of SCR catalyst for marine SCR system.

• Clean Technology
• /
• v.25 no.1
• /
• pp.81-90
• /
• 2019

A dielectric barrier discharge (DBD) plasma reactor packed with $Ni-CeO_2/{\gamma}-Al_2O_3$ catalyst was used for the dry ($CO_2$) reforming of propane (DRP) to improve the production of syngas (a mixture of $H_2$ and CO) and the catalyst stability. The plasma-catalytic DRP was carried out with either thermally or plasma-reduced $Ni-CeO_2/{\gamma}-Al_2O_3$ catalyst at a $C_3H_8/CO_2$ ratio of 1/3 and a total feed gas flow rate of $300mL\;min^{-1}$. The catalytic activities associated with the DRP were evaluated in the range of $500{\sim}600^{\circ}C$. Following the calcination in ambient air, the ${\gamma}-Al_2O_3$ impregnated with the precursor solution ($Ni(NO_3)_2$ and $Ce(NO_3)_2$) was subjected to reduction in an $H_2/Ar$ atmosphere to prepare $Ni-CeO_2/{\gamma}-Al_2O_3$ catalyst. The characteristics of the catalysts were examined using X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectrometry (EDS), temperature programmed reduction ($H_2-TPR$), temperature programmed desorption ($H_2-TPD$, $CO_2-TPD$), temperature programmed oxidation (TPO), and Raman spectroscopy. The investigation revealed that the plasma-reduced $Ni-CeO_2/{\gamma}-Al_2O_3$ catalyst exhibited superior catalytic activity for the production of syngas, compared to the thermally reduced catalyst. Besides, the plasma-reduced $Ni-CeO_2/{\gamma}-Al_2O_3$ catalyst was found to show long-term catalytic stability with respect to coke resistance that is main concern regarding the DRP process.

• Korean Chemical Engineering Research
• /
• v.59 no.1
• /
• pp.127-137
• /
• 2021

Air emission charge for nitrogen oxide as a precursor of fine dust has been introduced and implemented within the country from 2020. Therefore, the development of economical combustion technology for NOx reduction has got more needed urgently. This study investigated the air-staging effect as a way to reduce the NOx during combustion of domestic unused forest biomass, recently possible to secure REC (Renewable Energy Certification) as a substitute for overseas wood pellets in a 0.1 MWth circulating fluidized bed combustion test-rig. Operating conditions were comparison with and without air-staging, the supply position of tertiary air (6.4 m, 8.1 m, 9.4 m in the combustor) and variation of air-staging ratio (Primary air:Secondary air:Tertiary air=91%:9%:0%, 82%:9%:9%, 73%:9%:18%). NO and CO concentrations in flue gas, profiles of temperature and pressure at the height of the combustion, unburned carbon in sampled fly ash and combustion efficiency on operating conditions were evaluated. As notable results, NO concentration with air-staging application under tertiary air supply at 9.4 m in the combustor reduced 100.7 ppm compared to 148.8 ppm without air-staging while, CO concentration increased from 52.2 ppm without air-staging to 99.8 ppm with air-staging. However, among air-staging runs, when tertiary air supply amount at 6.4 m in the combustor increased by air-staging ratio (Primary air:Secondary air:Tertiary air=73%:9%:18%), NO and CO concentrations decreased the lowest 90.8 ppm and 66.1 ppm, respectively. Furthermore, combustion efficiency at this condition was improved to 99.3%, higher than that (98.3%) of run without air-staging.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.50 no.3
• /
• pp.19-34
• /
• 2022

This study was conducted to provide basic data that can be used when establishing Net Zero policies and implementation plans for non-urban settlements by quantitatively analyzing the Net Zero contribution to green infrastructure in rural areas corresponding to non-urban settlements. The main purpose is to first, systematize green infrastructure in rural areas, secondly derive basic units for each element of green infrastructure, and thirdly quantify and present the impact on Net Zero in Korea using these. In this study, CVR(Content Validity Ration) analysis was performed to verify the adequacy of green infrastructure elements in rural areas derived through research and analysis of previous studies, is as follows. First, Hubs of Green infrastructure in rural area include village forests, wetlands, farm land, and smart farms with a CVR value of .500 or higher. And Links of Green infrastructure in rural area include streams, village green areas, and LID (rainwater recycling). Second, the basic unit for each green infrastructure element was presented by classifying it into minimum, maximum, and median values using the results of previous studies so that it could be used for spatial planning and design for Net Zero. Third, when Green infrastructure in rural areas is applied to non-urban settlements in Korea, it is analyzed that it has the effect of indirectly reducing CO₂ by at least 70.76 million tons and up to 141.16 million tons. This is 3.4 to 6.7 times the amount of CO₂ emission from the agricultural sector in 2019, and it can be seen that the contribution to Net Zero is very high. It is expected to greatly contribute to the transformation of the ecosystem. This study quantitatively presented the carbon-neutral contribution to settlements located in non-urban areas, and by deriving the carbon reduction unit for each element of green infrastructure in rural areas, it can be used in spatial planning and design for carbon-neutral at the village level. It has significance as a basic research. In particular, the basic unit of carbon reduction for each green infrastructure factors will be usable for Net Zero policy at the village level, presenting a quantitative target when establishing a plan, and checking whether or not it has been achieved. In addition, based on this, it will be possible to expand and apply Net Zero at regional and city units such as cities, counties, and districts.

• Horticultural Science & Technology
• /
• v.29 no.5
• /
• pp.389-406
• /
• 2011

As part of a feasibility study for introducing carbon labeling of fruit products in Korea, we explore the use of carbon footprints for Korean kiwifruit from Gyeongnam region as a case study. In Korea, the Korean Environmental Industry and Technology Institute (KEITI) is responsible for the carbon footprint labeling certification, and has two types of certification programs: one program focuses on climate change response (carbon footprint labeling analysis) and the other on low-carbon products (reduction of carbon footprints analysis). Currently agricultural products have not yet been included in the program. Carbon labeling could soon be a prerequisite for the international trading of agricultural products. In general the carbon footprints of various agricultural products from New Zealand followed the methodology described in the ISO standards and conformed to the PAS 2050. The carbon footprint assessment focuses on a supply chain, and considers the foreground and the background systems. The basic scheme consists of four phases, which are the 'goal', 'scope', 'inventory analysis', and 'interpretation' phases. In the case of the carbon footprint of New Zealand kiwifruit the study tried to understand each phase's contribution to total GHG emissions. According to the results, shipping, orchard, and coolstore operation are the main life cycle stages that contribute to the carbon footprint of the kiwifruit supply chain stretching from the orchard in New Zealand to the consumer in the UK. The carbon emission of long-distance transportation such as shipping can be a hot-spot of GHG emissions, but can be balanced out by minimizing the carbon footprint of other life cycle phases. For this reason it is important that orchard and coolstore operations reduce the GHG-intensive inputs such as fuel or electricity to minimize GHG emissions and consequently facilitate the industry to compete in international markets. The carbon footprint labeling guided by international standards should be introduced for fruit products in Korea as soon as possible. The already established LCA methodology of NZ kiwifruit can be applied for fruit products as a case study.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.6
• /
• pp.667-676
• /
• 2006

The reduction of $Hg^{2+}$ in the aqueous phase results in the production of dissolved gaseous mercury(DGM), and the volatilization of DGM has been identified as an important mechanism for the loss of Hg from waterbodies to the atmosphere. Although mercury emission in the world is known to be mostly from Asia, there have been few studies of measuring DGM concentrations in lakes in Asia. In this study, DGM concentrations were measured at Juam reservoir($35^{\cir}00'N,\;127^{\circ}14'E$), Korea. The results showed that the average concentrations of DGM at the upper and down stream of the lake during summer time were $95{\pm}8\;and\;130{\pm}15$ pg/L, respectively and the concentration of total mercury(TM) at the upper and down stream was $2.1{\pm}0.7,\;1.7{\pm}0.3$ ng/L respectively. Average DGM concentration during summer time($101{\pm}14pg/L$) was approximately 5.5 times higher than that during fall($18{\pm}0.1pg/L$). The DGM concentrations ai the midstream decreased from 32 to 13.7 pg/L during rain event, while the TM concentrations increased from 2.2 ng/L to 2.7 ng/L indicating the deposition of mercury from the atmosphere. Also, the diurnal patterns between DGM concentrations and UV intensities were observed. Water temperatures and DOC concentrations were significantly related to DGM concentrations, while TM concentrations were negatively related to DGM concentrations(p<0.0001). Comparing with the study of Dill et al.,(2006) the average concentrations of DGM $(109{\pm}15pg/L)\;and\;TM(2.2{\pm} 0.4ng/L)$ at Juam reservoir were approximately 3 and 2.2 times higher than those measured in other lakes(DGM: $38{\pm}16pg/L$, TM: $1.0{\pm}1.2ng/L$).

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.9
• /
• pp.961-972
• /
• 2008

In 2004, total emissions of Greenhouse Gases(GHGs) in Korea was estimated to be about 590 million metric tons, which is the world's 10th largest emissions. Considering the much amount of nation's GHG emissions and growing nation's position in the world, GHG emissions in Korea should be reduced in near future. The CO$_2$ emissions from two sub-sections of energy sector in Korea, such as thermal power plant and industry section(including manufacturing and construction industries), was about 300 million metric tons in 2004 and this is 53.3% of total GHG emissions in Korea. So, the mitigation of CO$_2$ emissions in these two section is more important and more effective to reduce the nation's total GHGs than any other fields. In addition, these two section have high potential to qualitatively and effectively apply the CCS(Carbon Capture and Storage) technologies due to the nature of their process. There are several CCS technologies applied to these two section. In short term, the chemical absorption technology using amine as a absorbent could be the most effectively used. In middle or long term, pre-combustion technology equipped with ATR(Autothermal reforming), or MSR-$H_2$(Methane steam reformer with hydrogen separation membrane reactor) unit and oxyfuel combustion such as SOFC+GT(Solid oxide fuel cell-Gas turbine) process would be the promising technologies to reduce the CO$_2$ emissions in two areas. It is expected that these advanced CCS technologies can reduce the CO$_2$ avoidance cost to $US 8.5-43.5/tCO$_2$. Using the CCS technologies, if the CO$_2$ emissions from two sub-sections of energy sector could be reduced to even 10% of total emissions, the amount of 30 million metric tons of CO$_2$ could be mitigated.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.11 no.1
• /
• pp.24-34
• /
• 2008

To mitigate the climate change and global warming, various technologies have been internationally proposed for reducing greenhouse gas emissions. Especially, in recent, carbon dioxide capture and storage (CCS) technology is regarded as one of the most promising emission reduction options that $CO_2$ be captured from major point sources (eg., power plant) and transported for storage into the marine geological structure such as deep sea saline aquifer. The purpose of this paper is to review the latest progress on the development of technologies for $CO_2$ storage in marine geological structure and its perspective in republic of Korea. To develop the technologies for $CO_2$ storage in marine geological structure, we carried out relevant R&D project, which cover the initial survey of potentially suitable marine geological structure fur $CO_2$ storage site and monitoring of the stored $CO_2$ behavior, basic design for $CO_2$ transport and storage process including onshore/offshore plant and assessment of potential environmental risk related to $CO_2$ storage in geological structure in republic of Korea. By using the results of the present researches, we can contribute to understanding not only how commercial scale (about 1 $MtCO_2$) deployment of $CO_2$ storage in the marine geological structure of East Sea, Korea, is realized but also how more reliable and safe CCS is achieved. The present study also suggests that it is possible to reduce environmental cost (about 2 trillion Won per year) with developed technology for $CO_2$ storage in marine geological structure until 2050.