• Clean Technology
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• v.25 no.4
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• pp.316-323
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• 2019

In order to enhance combustion efficiency and reduce atmosphere pollutants, it is essential to measure carbon monoxide (CO) concentration precisely in combustion exhaust. CO is the important gas species regarding pollutant emission and incomplete combustion because it can trade off with NOx and increase rapidly when incomplete combustion occurs. In the case of a steel annealing system, CO is generated intentionally to maintain the deoxidation atmosphere. However, it is difficult to measure the CO concentration in a combustion environment in real-time, because of unsteady combustion reactions and harsh environment. Tunable Diode Laser Absorption Spectroscopy (TDLAS), which is an optical measurement method, is highly attractive for measuring the concentration of certain gas species, temperature, velocity, and pressure in a combustion environment. TDLAS has several advantages such as sensitive, non-invasive, and fast response, and in-situ measurement capability. In this study, a combustion system is designed to control the equivalence ratio. Also, the combustion exhaust gases are produced in a Liquefied Petroleum Gas (LPG)/air flame. Measurement of CO concentration according to the change of equivalence ratio is confirmed through TDLAS method and compared with the simulation based on Voigt function. In order to measure the CO concentration without interference from other combustion products, a near-infrared laser at 4300.6 cm^-1 was selected.

• Journal of the Korean Vacuum Society
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• v.14 no.2
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• pp.78-83
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• 2005

Nanometric crystalline silicon (no-Si) embedded in dielectric medium has been paid attention as an efficient light emitting center for more than a decade. In nc-Si, excitonic electron-hole pairs are considered to attribute to radiative recombination. However the surface defects surrounding no-Si is one of non-radiative decay paths competing with the radiative band edge transition, ultimately which makes the emission efficiency of no-Si very poor. In order to passivate those defects - dangling bonds in the $Si:SiO_2$ interface, hydrogen is usually utilized. The luminescence yield from no-Si is dramatically enhanced by defect termination. However due to relatively high mobility of hydrogen in a matrix, hydrogen-terminated no-Si may no longer sustain the enhancement effect on subsequent thermal processes. Therefore instead of easily reversible hydrogen, phosphorus was introduced by ion implantation, expecting to have the same enhancement effect and to be more resistive against succeeding thermal treatments. Samples were Prepared by 400 keV Si implantation with doses of $1\times10^{17}\;Si/cm^2$ and by multi-energy Phosphorus implantation to make relatively uniform phosphorus concentration in the region where implanted Si ions are distributed. Crystalline silicon was precipitated by annealing at $1,100^{\circ}C$ for 2 hours in Ar environment and subsequent annealing were performed for an hour in Ar at a few temperature stages up to $1,000^{\circ}C$ to show improved thermal resistance. Experimental data such as enhancement effect of PL yield, decay time, peak shift for the phosphorus implanted nc-Si are shown, and the possible mechanisms are discussed as well.

• The Korean Journal of Nuclear Medicine
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• v.37 no.5
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• pp.288-300
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• 2003

Purpose: To obtain regional blood flow and tissue-blood partition coefficient with time-activity curves from ${H_2}^{15}O$ PET, fitting of some parameters in the Kety model is conventionally accomplished by nonlinear least squares (NLS) analysis. However, NLS requires considerable compuation time then is impractical for pixel-by-pixel analysis to generate parametric images of these parameters. In this study, we investigated several fast parameter estimation methods for the parametric image generation and compared their statistical reliability and computational efficiency. Materials and Methods: These methods included linear least squres (LLS), linear weighted least squares (LWLS), linear generalized least squares (GLS), linear generalized weighted least squares (GWLS), weighted Integration (WI), and model-based clustering method (CAKS). ${H_2}^{15}O$ dynamic brain PET with Poisson noise component was simulated using numerical Zubal brain phantom. Error and bias in the estimation of rCBF and partition coefficient, and computation time in various noise environments was estimated and compared. In audition, parametric images from ${H_2}^{15}O$ dynamic brain PET data peformed on 16 healthy volunteers under various physiological conditions was compared to examine the utility of these methods for real human data. Results: These fast algorithms produced parametric images with similar image qualify and statistical reliability. When CAKS and LLS methods were used combinedly, computation time was significantly reduced and less than 30 seconds for $128{\times}128{\times}46$ images on Pentium III processor. Conclusion: Parametric images of rCBF and partition coefficient with good statistical properties can be generated with short computation time which is acceptable in clinical situation.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.12
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• pp.803-812
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• 2014

This study assesses the strategy and performance of Eco-industrial Park (EIP) initiative implemented by Korea Industrial Complex Corporation (KICOX) with the support of Ministry of Trade, Industry and Energy (MOTIE), Korea since 2005 to 2013 and recommends future directions. After the concept of EIP based on industrial symbiosis (IS) is introduced, the background and implementation procedure of the EIP initiative are described. Then, economic and environmental achievement was assessed. During the project periods (2005-2013), 449 industrial symbiosis project were explored, among which 296 projects have been implemented. Among (Of these 296 projects,) them, 244 projects have been completed in which 118 projects have been commercialized which shows 48% commercialization rate of the completed projects. Through these commercialized projects, around 311.1 billion won/year of economic benefits and reduction of waste by-products of 828,113 tons/year, wastewater of 215,517 tons/year, reduction in energy consumption of 250,475 toe/year and GHG emission reduction of 1,107,189 $tCO_2/year$ were achieved. This results confirmed that EIP initiative based on industrial symbiosis can enhance eco-efficiency of industrial parks and harmonize economy and environment. However, there are obstacles like absence of interagency coordination and cooperation, laws and institutional barriers, increased demand for local governments, funding for project investment. Thus, to utilize EIP initiative as a strategic tool for competiveness and environmental management of industrial parks, it needs intergovernmental collaboration and interdisciplinary approach to lower barrier in implementation.

• The Journal of Korean Society for Radiation Therapy
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• v.17 no.2
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• pp.87-94
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• 2005

Purpose : Heavy metal use when producing the block from the workshop. At this time, production of heavy metal dust and fume gives risk in human. This like heavy metal to improve seriousness through measurement and analysis. And by the quest in solution is purpose of this thesis. Materials and Methods : Organization is Inductively Coupled Plasma Atomic Emission Spectrometer, and the object is Deajeon city 4 workshops in university hospital radiation oncology (Bismuth, Lead, Tin and cadmium). Method is the ppb the pumping it does at unit, comparison analysis. And the Calculation heavy metal standard level in air through heavy metal standard level in body and blood, so Heavy metal temporary standard set. Results : Subterranean existence room air quality the administration laws appointed Lead and Cadmium's exposure recommend that it is $3{\mu}g/m^3\;and\;2{\mu}g/m^3$. And Bismuth and Tin decides $7{\mu}g/m^3\;and\;6{\mu}g/m^3$ through standard level in air heavy metal and standard level in body and blood. Heavy metal measurement level of workshops in 4 university hospital Daejeon city compares with work existence and nonexistence. On work nonexistence almost measurement level is below the recommend level. But work existence case express high level. Also consequently in composition ratio of the block is continuous with the detection ratio. Conclusion : Worker's heavy metal contamination imbrued serious for solution founds basic part. In hospital may operation on local air exhauster and periodical efficiency check, protector offer, et al. And worker have a correct understanding part of heavy metal contamination, and have continuous interest, health control. Finally, learned society sphere administer to establishment standard level and periodical measurement. And it founds basic solution plan of periodical special health checkup.

• Journal of Korea Water Resources Association
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• v.42 no.1
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• pp.33-50
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• 2009

The impact on hydrologic components considering future potential climate, land use change and vegetation cover information was assessed using SLURP (Semi-distributed Land-Use Runoff Process) continuous hydrologic model. The model was calibrated (1999 - 2000) and validated (2001 - 2002) for the upstream watershed ($260.4\;km^2$) of Gyeongancheon water level gauging station with the coefficient of determination and Nash-Sutcliffe efficiency ranging from 0.77 to 0.60 and 0.79 to 0.60, respectively. Two GCMs (MIROC3.2hires, ECHAM5-OM) future weather data of high (A2), middle (A1B) and low (B1) emission scenarios of the IPCC (Intergovernmental Panel on Climate Change) were adopted and the data was corrected by 20C3M (20th Century Climate Coupled Model) and downscaled by Change Factor (CF) method using 30 years (1977 - 2006, baseline period) weather data. Three periods data of 2010 - 2039 (2020s), 2040 - 2069 (2050s), 2070 - 2099 (2080s) were prepared. To reduce the uncertainty of land surface conditions, future land use and vegetation canopy prediction were tried by CA-Markov technique and NOAA NDVI-Temperature relationship respectively. MIROC3.2 hires and ECHAM5-OM showed increase tendency in annual streamflow up to 21.4 % for 2080 A1B and 8.9 % for 2050 A1B scenario respectively. The portion of future predicted ET about precipitation increased up to 3 % in MIROC3.2 hires and 16 % in ECHAM5-OM respectively. The future soil moisture content slightly increased compared to 2002 soil moisture.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.11
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• pp.1615-1634
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• 2004

A review was undertaken to obtain information on the sustainability of pig free-range production systems including the management, performance and health of pigs in the system. Modern outdoor rearing systems requires simple portable and flexible housing with low cost fencing. Local pig breeds and outdoor-adapted breeds for certain environment are generally more suitable for free-range systems. Free-range farms should be located in a low rainfall area and paddocks should be relatively flat, with light topsoil overlying free-draining subsoil with the absence of sharp stones that can cause foot damage. Huts or shelters are crucial for protecting pigs from direct sun burn and heat stress, especially when shade from trees and other facilities is not available. Pigs commonly graze on strip pastures and are rotated between paddocks. The zones of thermal comfort for the sow and piglet differ markedly; between 12-22$^{\circ}C$ for the sow and 30-37$^{\circ}C$ for piglets. Offering wallows for free-range pigs meets their behavioural requirements, and also overcomes the effects of high ambient temperatures on feed intake. Pigs can increase their evaporative heat loss via an increase in the proportion of wet skin by using a wallow, or through water drips and spray. Mud from wallows can also coat the skin of pigs, preventing sunburn. Under grazing conditions, it is difficult to control the fibre intake of pigs although a high energy, low fibre diet can be used. In some countries outdoor sows are fitted with nose rings to prevent them from uprooting the grass. This reduces nutrient leaching of the land due to less rooting. In general, free-range pigs have a higher mortality compared to intensively housed pigs. Many factors can contribute to the death of the piglet including crushing, disease, heat stress and poor nutrition. With successful management, free-range pigs can have similar production to door pigs, although the growth rate of the litters is affected by season. Piglets grow quicker indoors during the cold season compared to outdoor systems. Pigs reared outdoors show calmer behaviour. Aggressive interactions during feeding are lower compared to indoor pigs while outdoor sows are more active than indoor sows. Outdoor pigs have a higher parasite burden, which increases the nutrient requirement for maintenance and reduces their feed utilization efficiency. Parasite infections in free-range pigs also risks the image of free-range pork as a clean and safe product. Diseases can be controlled to a certain degree by grazing management. Frequent rotation is required although most farmers are keeping their pigs for a longer period before rotating. The concept of using pasture species to minimise nematode infections in grazing pigs looks promising. Plants that can be grown locally and used as part of the normal feeding regime are most likely to be acceptable to farmers, particularly organic farmers. However, one of the key concerns from the public for free-range pig production system is the impact on the environment. In the past, the pigs were held in the same paddock at a high stocking rate, which resulted in damage to the vegetation, nutrient loading in the soil, nitrate leaching and gas emission. To avoid this, outdoor pigs should be integrated in the cropping pasture system, the stock should be mobile and stocking rate related to the amount of feed given to the animals.

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.1
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• pp.29-34
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• 2019

Purpose An examination guide is a useful medium to provide the patient with an overview, pre- and post-test preparation, and precautions of nuclear testing. The design and arrangement of existing written texts and announcements were evaluated to elucidate the comprehension of patients undergoing testing. Materials and Methods Informational material describing bone scanning and $^{201}thallium$ myocardium perfusion single-photon emission computed tomography (SPECT), as a secondary examination, which accounts for the largest portion of gamma imaging at Asan Hospital (Seoul, South Korea), was selected as an improvement target in consultation with a national innovation center. Existing informational material was dispensed to patients scheduled for bone scans from November 2016 to February 2017 and the revised material was issued from March 2017 to May 2017. A survey was conducted of 200 patients who underwent $^{201}thallium$ myocardium perfusion SPECT before and after the revisions (n = 100 each time period) to assess the patients' understanding of the informational material. Results When comparing the use of the conventional vs. revised material, the number of patients who received treatment before bone scanning had decreased from 130 to 60, while the number of those who required additional imaging decreased from 53 to 14. Prior to the revision, 43% of patients underwent testing before preparation and 18% underwent additional testing. The decreased need for additional image acquisition after revision of the informational material resulted in a decrease in acquisition time of about 2 min, from 16.5 to 14.2 min. In the case of $^{201}thallium$ myocardium perfusion SPECT, patient comprehension of all five items surveyed had increased, while the number of patients who had repeatedly asked about various facets of the procedure pre- and post-testing had decreased from 36% to 16% and 31% to 14%, respectively. Conclusion Lower patient comprehension is accompanied by a decrease in image quality due to non-compliance during pre-testing and may lead to repetitive questions from the patient, which may also negatively affect the fatigue and work efficiency of the examiner. Improved readability and visibility of informational material through visualization was correlated with greater patient comprehension as well as improved image quality and acquisition time.

• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.526-535
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• 2021

Spatial sampling design plays an important role in GIS-based modeling studies because it increases modeling efficiency while reducing the cost of sampling. In the field of agricultural systems, research demand for high-resolution spatial databased modeling to predict and evaluate climate change impacts is growing rapidly. Accordingly, the need and importance of spatial sampling design are increasing. The purpose of this study was to design spatial sampling of paddy fields (11,386 grids with 1 km spatial resolution) in Korea for use in agricultural spatial modeling. A stratified random sampling design was developed and applied in 2030s, 2050s, and 2080s under two RCP scenarios of 4.5 and 8.5. Twenty-five weather and four soil characteristics were used as stratification variables. Stratification and sample allocation were optimized to ensure minimum sample size under given precision constraints for 16 target variables such as crop yield, greenhouse gas emission, and pest distribution. Precision and accuracy of the sampling were evaluated through sampling simulations based on coefficient of variation (CV) and relative bias, respectively. As a result, the paddy field could be optimized in the range of 5 to 21 strata and 46 to 69 samples. Evaluation results showed that target variables were within precision constraints (CV<0.05 except for crop yield) with low bias values (below 3%). These results can contribute to reducing sampling cost and computation time while having high predictive power. It is expected to be widely used as a representative sample grid in various agriculture spatial modeling studies.

• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.267-274
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• 2022

Excess nitrogen (N) flowing from livestock manure to water systems poses a serious threat to the natural environment. Thus, livestock wastewater management has recently drawn attention to this related field. This study first attempted to obtain the optimal conditions for the further volatilization of NH₃ gas generated from pig wastewater by adjusting the amount of injected magnesia (MgO). At 0.8 wt.% of MgO (by pig wastewater weight), the volatility rate of NH₃ increased to 75.5% after a day of aeration compared to untreated samples (pig wastewater itself). This phenomenon was attributed to increases in the pH of pig wastewater as MgO dissolved in it, increasing the volatilization efficiency of NH₃. The initial pH of pig wastewater was 8.4, and the pH was 9.2 when MgO was added up to 0.8 wt.%. Second, the residual ammonia nitrogen (NH₄⁺-N) in pig wastewater was removed by precipitation in the form of struvite (NH₄MgPO₄·6H₂O) by adjusting the pH after adding MgO and H₃PO₄. Struvite produced in the pig wastewater was identified by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) analysis. White precipitates began to form at pH 6, and the higher the pH, the lower the concentration of NH₄⁺-N in pig wastewater. Of the total 86.1% of NH₄⁺-N removed, 62.4% was achieved at pH 6, which was the highest removal rate. Furthermore, how struvite changes with pH was investigated. Under conditions of pH 11 or higher, the synthesized struvite was completely decomposed. The yield of struvite in the precipitate was determined to be between 68% and 84% through a variety of analyses.