• Nuclear Engineering and Technology
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• v.21 no.4
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• pp.287-293
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• 1989

The purpose of this study was to develop a rapid and effective method of laser-induced fluorescence analysis for thrace amounts of Sm, Eu and Tb in nuclear fuels. The features of the method are the use of the distinct fluorescence wavelengths and the discriminative lifetimes of the respective elements when excited by a pulsed nitrogen laser. Fluorescence signals of the three elements were isolated by adequate selection of the filters or complexing agents (HFA, TTA) or discriminative delay and gate times in the signal processing circuit. It was found that S $m^{+3}$ and E $u^{+3}$ emitted strong fluorescence in the two complexing agent solutions or HFA and TTA. But in the case or T $b^{+3}$, the fluorescence signal was detected only in HFA solution. With respect to the concentrations of S $m^{+3}$, E $u^{+3}$ and T $b^{+3}$, the fluorescence signal intensities gave superior linearities in the range of 5 ppb-10 ppm for S $m^{+3}$, 0.5 ppb-1 ppm for E $u^{+3}$, and 0.1 ppb-300 ppb for T $b^{+3}$, The detection limits obtained were 5 ppb for S $m^{+3}$, 0.1 ppb for E $u^{+3}$, and 0.01 ppb for T $b^{+3}$, respectively.

• Journal of radiological science and technology
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• v.35 no.4
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• pp.335-343
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• 2012

Intensity-modulated radiotherapy(IMRT) have the ability to provide better dose conformity and sparing of critical normal tissues than three-dimensional radiotherapy(3DCRT). Especially, with the benefit of health insurance in 2011, its use now increasingly in many modern radiotherapy departments. Also the use of linear accelerator with high-energy photon beams over 10 MV is increasing. As is well known, these linacs have the capacity to produce photonueutrons due to photonuclear reactions in materials with a large atomic number such as the target, flattening filters, collimators, and multi-leaf collimators(MLC). MLC-based IMRT treatments increase the monitor units and the probability of production of photoneutrons from photon-induced nuclear reactions. The purpose of this study is to quantitatively evaluate the dose of photoneutrons produced from 3DCRT and IMRT technique for Rando phantom in cervical cancer. We performed the treatment plans with 3DCRT and IMRT technique using Rando phantom for treatment of cervical cancer. An Rando phantom placed on the couch in the supine position was irradiated using 15 MV photon beams. Optically stimulated luminescence dosimeters(OSLD) were attached to 4 different locations (abdomen, chest, head and neck, eyes) and from center of field size and measured 5 times each of locations. Measured neutron dose from IMRT technique increased by 9.0, 8.6, 8.8, and 14 times than 3DCRT technique for abdomen, chest, head and neck, and eyes, respectively. When using IMRT with 15 MV photonbeams, the photoneutrons contributed a significant portion on out-of-field. It is difficult to prevent high energy photon beams to produce the phtoneutrons due to physical properties, if necessary, It is difficult to prevent high energy photon beams to produce the phtoneutrons due to physical properties, if necessary, it is need to provide the additional safe shielding on a linear accelerator and should therefore reduce the out-of-field dose.

• Korean Journal of Environment and Ecology
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• v.29 no.4
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• pp.626-635
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• 2015

Recently, the number of trail users in Korea has risen tremendously. Consequently, the cost of safety measures related to hiking is sharply increasing. Despite the safety cost input, the number of heart-related adverse events has been not decreasing. Therefore, this research aims to suggest the use of objective and quantitative trail use information in terms of course difficulty. The study site is Jirisan Dullegil (Jirisan Forest Trail). The currently available trail difficulty information either provides the difficulty rating in terms of 3 to 5 levels according to several empirical difficulty factors reported by staff who maintain the forest or simply states the distance of each trail. Thus, many trail visitors feel a great gap between the given information and actual difficulties they experience. In this study, we tried to assess the degree of difficulty by actual energy consumption. Calculating the volumetric oxygen consumption (VOC) by the distance and gradient not only makes possible an absolute rating but a comparison among the trails as well. Also, it is highly effective to simply describe the exercise intensity of a certain trail. Further, it is easy to check the VOCs' changes by switching the start-end points of the same trail. Providing the trail information of VOCs by sections and directions, we expect to prevent heart-related accidents.

• Macromolecular Research
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• v.17 no.12
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• pp.963-968
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• 2009

Liquid crystal (LC; E7 and/or ML-0249)-embedded, poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-co-HFP)-based, polymer electrolytes were prepared for use in dye-sensitized solar cells (DSSCs). The electrolytes contained 1-methyl-3-propylimidazolium iodide (PMII), tetrabutylammonium iodide (TBAI), and iodine ($I_2$), which participate in the $I_3^-/I^-$ redox couple. The incorporation of photochemically stable PVdF-co-HFP in the DSSCs created a stable polymer electrolyte that resisted leakage and volatilization. DSSCs, with liquid crystal(LC)-embedded PVdF-co-HFP-based polymer electrolytes between the amphiphilic ruthenium dye N719 absorbed to the nanocrystalline $TiO_2$ photoanode and the Pt counter electrode, were fabricated. These DSSCs displayed enhanced redox couple reduction and reduced charge recombination in comparison to that fabricated from the conventional PVdF-co-HFP-based polymer electrolyte. The behavior of the polymer electrolyte was improved by the addition of optimized amounts of plasticizers, such as ethylene carbonate (EC) and propylene carbonate (PC). The significantly increased short-circuit current density ($J_{sc}$, $14.60\;mA/cm^2$) and open-circuit voltage ($V_{oc}$, 0.68 V) of these DSSCs led to a high power conversion efficiency (PCE) of 6.42% and a fill factor of 0.65 under a standard light intensity of $100\;mW/cm^2$ irradiation of AM 1.5 sunlight. A DSSC fabricated by using E7-embedded PVdF-co-HFP-based polymer electrolyte exhibited a maximum incident photon-to-current conversion efficiency (IPCE) of 50%.

• Journal of Nutrition and Health
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• v.56 no.4
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• pp.391-403
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• 2023

Purpose: This study evaluated the validity of a physical activity classification table (PACT) based on total energy expenditure (TEE) and physical activity level (PAL) measured using the doubly labeled water (DLW) method in Korean adults and the elderly. Methods: A total of 141 (male 70, female 71) adults and elderly were included. The reference standards TEE_DLW, PAL_DLW were measured over a 14-day period using DLW. A 24-hour physical activity diary was kept for three days (two days during the week and one day on the weekend). PAL_PACT was calculated by classifying the activity type and intensity using the PACT. PAL_PACT was multiplied by resting energy expenditure measured by indirect calorimetry to estimate TEE_PACT. Results: The mean age of the study participants was 50.5 ± 18.8 years, and the mean body mass index was 23.4 ± 3.3 kg/m². A comparison of TEE_DLW and TEE_PACT by sex and age showed no significant differences. The bias, the difference between TEE_DLW and TEE_PACT, was male 17.3 kcal/day and female -4.5 kcal/day. The percentage of accurate predictions (values within ± 10% of the TEE_DLW) of TEE_PACT was 58.6% in males and 54.9% in females, with the highest prediction values in the age group 40-64 years (70.9%) in males and over 65 years (73.9%) in females. The spearman correlation coefficient (r) between TEE_PACT and TEE_DLW was 0.769, indicating a significant positive correlation (p < 0.001). Conclusion: In this study, the use of a new PACT for calculating TEE and PAL was evaluated as valid. A web version of the software program and a smartphone application need to be developed using PACT to make it easier to apply for research purposes.

• Economic and Environmental Geology
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• v.47 no.2
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• pp.193-204
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• 2014

Shale gas has caused a change in the dynamics of gas market since development of horizontal drilling technic and hydraulic fracturing technic caused its commercial production. The commercial amount of shale gas is 187.5 trillions $m^3$ so human can use it for 59 years and the amount will increase in the future. Several nations such as USA, Canada, China and Russia have more and more interested in shale gas as a futuristic major energy source. In accordance with this trend in the world, the amount of studying theses for development of shale gas have increased so their theses became important increasingly. The number of searched theses (1986 ~ The first half of 2013) is 3,468 and has increased recently. Among 89 nations studying shale gas, USA has 637 theses as No.1 in the world. 1,813 global studying institutes have studied shale gas; in the analysis result of several studying institutes, US geological survey institute was ranked as No.1 for the quality level of shale gas study and intensity of global cooperation.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.105-109
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• 2020

This study was conducted to the improvement of solar light-based artificial light supply system and effect of lettuce cultivation. The artificial light supply system was consisted of units such as light source, power, system measurement and controller. The light source supply was composed of a solar transmitter and an LED lamp. The power supply consisted of an leakage breaker, SMPS, LED controller and relay. The solar transmitter was made of a quartz optical fiber with optimal light transmission. Artificial light used white lamp among LEDs. System measurement and control consisted of touch screen, Zigbee communication module and light quantity sensor. The results of test confirmed that the LED light is automatically activated when the intensity measured by the light intensity sensor is 200 μmolm^-2s^-1 or less. Moreover, the leaf length, root length, chlorophyll content and root fresh weight of optical fiber treatment was hight than LED lamp treatment. Therefore, it can be inferred that the energy-saving solar light collector device can be effective in the indoor lettuce production. However, the use of LED lamp is also recommended to assure the availability of sufficient sunlight in cloudy and rainy days.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.50-57
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• 2022

Ti-In-Zn-O (TIZO)/Ag/TIZO multilayer transparent electrodes were prepared on glass substrates at room temperature using RF/DC magnetron sputtering. Obtained multilayer structure comprising TIZO/Ag/TIZO (10 nm/10 nm/40 nm) with the total thickness of 60 nm showed a transmittance of 86.5% at 650 nm and a sheet resistance of 8.1 Ω/□. The multilayer films were expected to be applicable for use in energy-saving smart window based on polymer-dispersed liquid crystal (PDLC) because of their transmittance properties to effectively block infrared rays (heat rays). We investigated the effects of the content ratio of prepolymer, the thickness of the PDLC coating layer, and the ultraviolet (UV) light intensity on electro-optical properties, and the surface morphology of polyester acrylate-based PDLC systems using new TIZO/Ag/TIZO transparent conducting electrodes. A PDLC cell with a thickness of 15 ㎛ PDLC layer photocured at an UV intensity of 1.5 mW/cm² exhibited good driving voltage, favorable on-state transmittance, and excellent off-haze. The LC droplets formed on the surface of the polymer matrix of the PDLC composite had a size range of 1 to 3 ㎛ capable of efficiently scattering incident light. Also, the PDLC-based smart window manufactured using TIZO/Ag/TIZO multi-layered transparent electrodes in this study exhibited a light brown, which will have an advantage in terms of aesthetics.

• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.454-461
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• 2015

This study aims to classify the biotope types based on the vegetation community in built-up areas by different land use and to map the plant communities. By classifying biotopes according to a taxonomic system, the characteristics of a biological community can be well-represented. The biotope classification indexes for the target area include human behavioral factors such as land use intensity, land-use patterns and land-cover types. The type classification was divided into four hierarchic ranks starting with Biotope Class, next by Biotope Group and Biotope Type and lastly by Biotope Sub-Type. The Biotope Class was first divided into two areas: the areas improved by humans and the areas unimproved by humans. The improved areas were again divided into permeable and non-permeable regions on the Biotope Group level. In the Biotope Type level, permeable paving areas were divided into areas with wide gap pavers and those with narrow gap pavers. The differential species of each biotope type are Lindera glauca, Conyza canadensis, Mazus pumilus, Vicia tetrasperma, Crepidiastrum sonchifolium, Zoysis japonica, Potentilla supina and Festuca arundinacea. The results of this study suggest that the biotope classification methodology, using a subjective phytosociological approach, is a useful and valuable tool and the results also suggest the possibility of applying more objective and scientific methods in mapping and classifying various environments.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.4
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• pp.43-48
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• 2006

Recently, many researchers have shown great interest in wind-photovoltaic hybrid generation system which promotes electric power supply safely and progress of energy usage efficiently with complementary cooperation of a wind generation system and photovoltaic generation system. To use this hybrid generation system stably and effectively, we established a system which can acquire, analyse and save data and monitored remotely using internet. We constructed the signal conditioning circuit and used many kinds of converters to measure physical quantities such as wind velocity, intensity of illumination and temperature as well as many kinds of voltage and current for AC and DC. we acquired data from computer with data acquisition board, developed server program and client program which can download data that is monitored and saved in realtime at remote place. We analysed the measured data in relation to many conditions such as time and weather conditions.