• Journal of the Korean Society of Radiology
• /
• 제15권4호
• /
• pp.429-435
• /
• 2021

In intracavitary radiotherapy, incorrect location of the source can cause excessive dose to normal tissue, so it is essential to evaluate the location accuracy of the source. In this study, basic research was performed on digital line dosimeter based on lead (II) oxide (PbO) to improve analog verification method. Therefore, a polycrystalline PbO unit cell dosimeter was manufactured and the measurement performance for Ir-192 sources was evaluated. As a result, the reproducibility satisfies the evaluation criteria of 1.5% with a relative standard deviation of 0.85%. Linearity showed excellent results with a linear coefficient of R² of 0.9998. In the case of distance dependence evaluation, the power function R² showed 0.9855 for PbO and 0.9974 for diode, and the overall average difference was 1.66% for PbO and 2.18% for diode. This study presents the basic detection performance of the polycrystalline PbO dosimeter for the Ir-192 source and can provide basic data in the field of radiation measurement.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• 제55권5호
• /
• pp.714-720
• /
• 2022

A dietary comparison of yellow goosefish Lophius litulon in the South Sea and Yellow Sea was performed by analyzing stomach contents. Using a bottom trawl net from fisheries resources survey vessels of the National Institute of Fisheries Science, 326 individuals were collected from the South Sea and 166 individuals were collected from the Yellow Sea. The total length range of L. litulon was 5.3-68.4 cm for individuals collected from the South Sea and 7.5-55.1 cm for individuals collected from the Yellow Sea. Based on the index of relative importance and the variation in stomach contents by fish size, L. litulon was found to be a piscevore and a spatiotemporally opportunistic feeder fish that fed mainly on pisces. There were differences in the composition of the stomach contents by season, location, and the interaction between the season and the location. Thus, the diet of L. litulon is affected by the prey abundance and prey spectrum of the habitat.

• Journal of the Korean Society for Library and Information Science
• /
• 제56권1호
• /
• pp.5-25
• /
• 2022

In most countries, public libraries are knowledge information centers, complex cultural spaces, lifelong learning facilities, and third places for local residents. The social homage spoken on the premise of this identity and socio-cultural role is the knowledge and information agora, cultural infrastructure, living room in the city, and the university of the people. However, if there is a significant gap between public libraries regardless of country or region, it will inevitably lead to information gaps, regional gaps, and cultural inequality and cultural welfare gaps among local residents. This study is regarded as the essence of regional cultural facilities and premised that the regional gap in public libraries is a factor of regional cultural gaps. Based on this premise, the gap between the location quotient, input indicators, and output indicators of public libraries of regional governments in Korea and basic local governments in the Gyeongbuk region was analyzed. And this study derived core elements through correlation and regression analysis of input and output indicators of all public libraries nationwide, developed a management model for each indicator, and suggested a plan to resolve the relative gap for public libraries by city and county in Gyeongbuk.

• Journal of the Korea institute for structural maintenance and inspection
• /
• 제27권4호
• /
• pp.45-53
• /
• 2023

In this study, to analyze the correlation of surface chloride and corrosion amount level according to the installation location of steel members exposed to the marine environment, the surface chloride and mean corrosion depth were evaluated by member units for box girder members of the offshore steel bridge and box specimens. The surface chloride was measured monthly using the Bresle method for one year. The corrosion amount was evaluated by converting the weight loss due to corrosion products generated in the monitoring steel plate into mean corrosion depth. As a measurement result of the surface chloride and corrosion amount, relative differences in surface chloride and mean corrosion depth were appeared depending on the shape or installation location of the steel members. Moreover, even if members of the same shape were installed in the same bridge, it was confirmed that the corrosion amount was increased locally and rapidly. The tendency of corrosion amount depending on the surface chloride was evaluated to analyze the correlation between surface chloride and corrosion amount, and the relation equations that can asseses the corrosion amount depending on the surface chloride were analyzed. From the results of the correlation between surface chloride and corrosion amount, it was found that the corrosion amount of the steel member affected by the surface chloride was varied up to about 1.15 times depending on the structural detail.

• Journal of the Korean Society of Radiology
• /
• 제81권2호
• /
• pp.379-394
• /
• 2020

Purpose To design a scoring system to predict malignancy of additional MRI-detected lesions in breast cancer patients. Materials and Methods Eighty-six lesions (64 benign and 22 malignant) detected on preoperative MRI of 68 breast cancer patients were retrospectively included. The clinico-radiologic features were correlated with the histopathologic results using the Student's t-test, Fisher's exact test, and logistic regression analysis. The scoring system was designed based on the significant predictive features of malignancy, and its diagnostic performance was compared with that of the Breast Imaging-Reporting and Data System (BI-RADS) category. Results Lesion size ≥ 8 mm (p < 0.001), location in the same quadrant as the primary cancer (p = 0.005), delayed plateau kinetics (p = 0.010), T2 isointense (p = 0.034) and hypointense (p = 0.024) signals, and irregular mass shape (p = 0.028) were associated with malignancy. In comparison with the BI-RADS category, the scoring system based on these features with suspicious non-mass internal enhancement increased the diagnostic performance (area under the receiver operating characteristic curve: 0.918 vs. 0.727) and detected three false-negative cases. With this scoring system, 22 second-look ultrasound examinations (22/66, 33.3%) could have been avoided. Conclusion The scoring system based on the lesion size, location relative to the primary cancer, delayed kinetic features, T2 signal intensity, mass shape, and non-mass internal enhancement can provide a more accurate approach to evaluate MRI-detected lesions in breast cancer patients.

• Journal of the Korea institute for structural maintenance and inspection
• /
• 제23권7호
• /
• pp.16-24
• /
• 2019

The corrosion amounts of steel structures can be different depending on their installation condition and height. Thus, their corrosion maintenance should be considered depending on installation conditions of local structural members. In this study, an atmospheric exposure test was conducted to evaluate the corrosion amount and the corrosion rate depending on the installation condition and height of a steel water gate using monitoring steel plates and corrosion environment measuring sensors. The mean corrosion depth was evaluated using the weight loss method and the galvanic corrosion current was measured by corrosion environment measuring sensors. Local corrosion rate of local structural member in steel water gate was estimated using measured mean corrosion depths and galvanic corrosion currents. From this measurement results, the corrosion damage in horizontal member of the cross beam was highly evaluated than those of other structural member as skin plate, etc. The relative difference in the corrosion rate of a local structural member could be highly affected by local corrosion environments of steel water gate members. Therefore, an appropriate maintenance method should be considered for local corrosion damages of local structural members determined by local corrosion environments of a steel water gate.

• Proceedings of the Korean Geotechical Society Conference
• /
• 한국지반공학회 1999년도 가을 학술발표회 논문집
• /
• pp.449-456
• /
• 1999

The concrete wall is the most useful of retaining structure which can obtain the engineering stability, but has problems that is not friendly with nature environment in a fine view, such as poor rear drainage, and shrinkage crack by temperature difference, etc. Because of this problems, the research for a segmental crib retaining wall has been performed. A segmental crib retaining wall is quickly and easily erected because is possible to be erected as the individual members, and is not sensitive to differential settlement and earthquakes. Also, it shows effective drainage and has a friendly advantage with nature environment because of being able to be planted with vines and shrubs in retaining walls The design of crib retaining walls has traditionally been based on classical soil mechanics theories. These theories, originally derived by Rankine(1857) and Coulomb(1776), assume that the wall acts as a rigid body. This assumption results in failure being predicted by either monolithic overturning or base sliding mechanisms. However, the wall consists of individual members which have been created a three dimensional grid. This grid confines an fill mass which becomes part of the wall. The filled wall resists the earth pressure with the same mechanism of classical gravity walls. Because of the flexibility of the individual segment, it allows relative movement between the individual members within the wall. The three dimensional flexible grid leads to stress redistribution when the wall is subjected to external or fill loads. Due to the flexibility and the stress redistribution, the failure of segmental crib wall consists of not only overturing and base sliding but the local deformation and the failure between the segmental members. It has been researched in the field that due to this flexibility and load redistribution, serviceability failure of segmental crib walls is unlikely to be due to overturning or base sliding. Therefore, in this study, the relative displacement appearance of retaining wall due to variation of inclination is measured to examine this behavior characteristics. Also, the behavior characteristics of retaining walls by surcharge load, and location of acting point of retaining wall rear, and the displacement characteristics and deflections are estimated about the existence and nonexistence of Rear Stretcher performing an role in transmitting earth pressure of Header and Stretcher organizing retaining walls. This research focuses on the characteristics due to the behavior of retaining walls. This research focuses on the characteristics due to the behavior of retaining walls.

• Economic and Environmental Geology
• /
• 제26권3호
• /
• pp.337-347
• /
• 1993

Mineralogical and geochemical studies on some pyrophyllite deposits in Milyang area, Kyeongnam Province (Milyang and Sungjin mine) were carried out in order to investigate dispersion patterns of chemical elements in altered volcanic wallrocks, and to interpret genetic environments of the pyrophyllite deposits. Cretaceous andesitic and tuffaceous rocks, and pyrophyllite ore specimens were collected from the dumps and drilling cores. Andesitic wallrocks were grouped as unaltered and altered rocks in the order of pyrophyllitization. Vertical dispersion patterns and relative mobilities of chemical elements in volcanic wallrocks were discussed. Geochemical environment in the Milyang area is characterized by the occurrence of boron minerals such as dumortierite coexisting with pyrophyllite ores, and tourmaline in granitic rocks. Unaltered andesitic rocks are mainly composed of plagioclase, pyroxene and hornblende, and were propylitized and saussuritized. Altered andesitic rocks are bleached and consist of quartz, sericite, pyrophyllite, kaolinite, chlorite and disseminated pyrite. Pyrophyllite ores are mainly composed of quartz, pyrophyllite, dumortierite, dissemianted pyrite and some diaspore. Enrichment of $SiO_2$, $Al_2O_3$, LOI (loss on ignition), As and Cr, and depletion of $K_2O$, $Na_2O$, CaO, MgO and total Fe are characteristic during alteration process. The REE patterns show that the pyrophyllite deposits could be originated from the continental margin volcanics. The $(La/Lu)_{cn}$ ratios of the pyrophyllite ores increase from 4.2~23.2 to 2.67~128.8 owing to strong acidic hydrothermal alteration. Vertical dispersion patterns of $Al_2O_3$, $K_2O$, $Na_2O$, CaO, MgO, $Fe_2O_3$ (total Fe), As, Au, Sb, Cr and Sr in the wallrocks show the location of orebodies. Particularly dispersion patterns of $Al_2O_3$ and Cr indicate the extension of orebodies. Anomalous distribution of Au, As and Sb in wallrocks shows potential for gold occurrence below the pyrophyllite deposits. Judging from the relative mobilities of elements in wallrocks, $Al_2O_3$ could be added from hydrothermal solution, and the silicified rone be formed from the excess of $SiO_2$.

• Journal of Pharmacopuncture
• /
• 제13권1호
• /
• pp.93-101
• /
• 2010

Objective : Standard of measurement in Korean Medicine has been changed in dynasty and location. Thus, cun (寸) and chi (尺) as unit of measurement for meridians and acupoints could be recognized as the length of equally divided portions of a certain long bone or the distance between two anatomical landmarks and as an symbolical meaning to date. The goal of this study is to propose a new standard measurement in the metric system for the relative measurement of cun and chi as unit of measurement for meridians and acupoints in normal male legs. Methods : This study was conducted by gauging each parts of normal male legs in the metric system and comparing to the relative measurement of cun and chi as follows; to calculate 1 cun, the length of each parts was divided into the unit of cun referred to Measurement of the Bone in Neijing Lingshu (靈樞 骨度篇); it was compared the unit of cun referred to Measurement of the Bone in Neijing Lingshu with cun which was calculated by dividing subject's height into 75 cun, respectively. Result : There has no significant difference in length of 1 cun among each leg's areas based on a standard of subject's height. The unit of cun by the metric length in the legs was similar to the unit of cun referred to Measurement of the Bone in Neijing Lingshu based on each subject's height. Conclusion : It is suggested that an unit of cun as the measurement for meridians and acupoints in the male legs should be considered to the ranges from 2.4cm to 2.6cm.

• Tunnel and Underground Space
• /
• 제9권4호
• /
• pp.306-314
• /
• 1999

In underground spaces including nuclear waste repository, prediction of air quantity, temperature/humidity and pollutant concentration is utmost important for space construction and management during the normal state as well as for determining the measures in emergency cases such as underground fires. This study aims at developing a model for underground space environment which has capabilities to take into account the effects of autocompression for the natural ventilation head calculation, to find the optimal location and size of fans and regulators, to predict the temperature and humidity by calculating the convective heat transfer coefficient and the sensible and latent heat transfer rates, and to estimate the pollutant levels throughout the network. The temperature/humidity prediction model was applied to a military storage underground space and the relative differences of dry and wet temperatures were 1.5 ~ 2.9% and 0.6 ~ 6.1%, respectively. The convection-based pollutant transport model was applied to two different vehicle tunnels. Coefficients of turbulent diffusion due to the atmospheric turbulence were found to be 9.78 and 17.35$m^2$/s, but measurements of smoke and CO concentrations in a tunnel with high traffic density and under operation of ventilation equipment showed relative differences of 5.88 and 6.62% compared with estimates from the convection-based model. These findings indicate convection is the governing mechanism for pollutant diffusion in most of the tunnel-type spaces.