• Bulletin of the Korean Chemical Society
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• v.22 no.1
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• pp.30-36
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• 2001

The crystal structures of fully dehydrated $Pd^{2+}$ - and $TI^{+}$ -exchanged zeolite X, $Pd_{18}TI_{56}Si_{100}Al_{92}O_{384}(Pd_{18}TI_{50-}X$, a = $24.935(4)\AA$ and $Pd_{21}TI_{50}Si_{100}Al_{92}O_{384}(Pd_{21}TI_{50-}X$ a = $24.914(4)\AA)$, have been determined by single-crystal X-ray diffraction methods in the cubic space group Fd3 at $21(1)^{\circ}C.$ The crystals were prepared using an exchange solution that had a $Pd(NH_3)_4Cl_2\;:TINO_3$ mole ratio of 50 : 1 and 200 : 1, respectively, with a total concentration of 0.05M for 4 days. After dehydration at $360^{\circ}C$ and 2 ${\times}$$10^{-6}$ Torr in flowing oxygen for 2 days, the crystals were evacuated at $21(1)^{\circ}C$ for 2 hours. They were refined to the final error indices $R_1$ = 0.045 and $R_2$ = 0.038 with 344 reflections for $Pd_{18}Tl_{56-}X$, and $R_1$ = 0.043 and $R_2$ = 0.045 with 280 reflections for $Pd_{21}Tl_{50-}X$; I > $3\sigma(I).$ In the structure of dehydrated $Pd_{18}Tl_{56-}X$, eighteen $Pd^{2+}$ ions and fourteen $TI^{+}$ ions are located at site I'. About twenty-seven $TI^{+}$ ions occupy site II recessed $1.74\AA$ into a supercage from the plane of three oxygens. The remaining fifteen $TI^{+}$ ions are distributed over two non-equivalent III' sites, with occupancies of 11 and 4, respectively. In the structure of $Pd_{21}Tl_{50-}X$, twenty $Pd^{2+}$ and ten $TI^{+}$ ions occupy site I', and one $Pd^{2+}$ ion is at site I. About twenty-three $TI^{+}$ ions occupy site II, and the remaining seventeen $TI^{+}$ ions are distributed over two different III' sites. $Pd^{2+}$ ions show a limit of exchange (ca. 39% and 46%), though their concentration of exchange was much higher than that of $TI^{+}$ ions. $Pd^{2+}$ ions tend to occupy site I', where they fit the double six-ring plane as nearly ideal trigonal planar. $TI^{+}$ ions fill the remaining I' sites, then occupy site II and two different III' sites. The two crystal structures show that approximately two and one-half I' sites per sodalite cage may be occupied by $Pd^{2+}$ ions. The remaining I' sites are occupied by $TI^{+}$ ions with Tl-O bond distance that is shorter than the sum of their ionic radii. The electrostatic repulsion between two large $TI^{+}$ ions and between $TI^{+}$ and $Pd^{2+}$ ions in the same $\beta-cage$ pushes each other to the charged six-ring planes. It causes the Tl-O bond to have some covalent character. However, $TI^{+}$ ions at site II form ionic bonds with three oxygens because the super-cage has the available space to obtain the reliable ionic bonds.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.119-128
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• 2018

Limit state design has been implemented in Korea since 2015; however, there exists no specification of lateral load determination on retaining wall due to the Korean standard traffic load on retaining wall's backfill surface. The lateral load from traffic depends on lane number, standard truck's axle loads and locations, loading distance from the inner wall. The concept of equivalent height of soil accounting for traffic loadings is typically used for design of retaining walls to quantify the traffic loads transmitted to the inner wall faces. Due to the different characteristics of the standard design trucks between Korea and US (AASHTO), the direct use of the guidelines from AASHTO LRFD leads to incorrect estimation of traffic load effects on retaining walls. This paper presents the results of evaluation of equivalent height of soil to reflect the Korean standard truck, based on the findings from analytical solutions using Bounessq's theory and numerical assessment using 2D finite element method. Consequently, it was found that the equivalent heights of soil from the Korean standard truck load were lower for lower retaining wall height.

• Journal of the Korean Society of Radiology
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• v.13 no.3
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• pp.433-438
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• 2019

The medical institutions use radiation generating devices and radioactive isotopes to diagnose and treat patients. The patient transporter performs work in an environment that is more likely to be exposed to radiation when compared with the general public, such as inevitably entering the radiation management area for patient transfer, or transferring the isotope-administered patient at a short distance. For this reason, we conducted a study to determine the degree of exposure of the patient transporter. The 12 patient transporters working at Incheon A General Hospital are eligible. From April 1, 2019 to April 30, 2019, the dosimeter was used in the chest for one month and the accumulated dose was measured. The dosimeter used was a Optically Stimulated Luminescence Dosimetry (OSLD) and the dose reading was OSLD Microstar Reading System. As a result of cumulative dose measurement for one month, the average of the deep dose was 0.13 mSv and the surface dose was 0.13 mSv, and the cumulative dose for one month was multiplied by 12 to estimate the cumulative dose expectation As a result, the average of the deep dose and the surface dose were 1.52 mSv and 1.51 mSv, respectively. It is necessary to classify the patient transporter as a frequent visitor in order to measure and manage the exposure dose, increase the knowledge of protection against radiation through education and training, and prevent radiation trouble through medical examination.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.725-733
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• 2018

With urbanization projects involving trunk roads progressing, many simple interchanges, which separate passing traffic into the main traffic and access subtraffic, are being constructed to maximize the traffic capacity. Under the current Road Connection Rule, the access-prohibited section in an interchange is determined based on the access lane and limit distance in the complete interchange road, but separate criteria for the simple interchange are not defined. This may cause confusion in the Road Management Office's determination of the access-prohibited section in the simple interchange, or lead to the application of the criteria for the access-prohibited section in the complete interchange without considering the features of such interchange. This study conducted a comparative analysis of the domestic and overseas systems related to the installation of access section in trunk roads, such as general national roads. This paper presents a survey of the methods for applying the access-prohibited section in the interchange along with the actual cases and proposes improvement measures for a rational calculation of the access prohibited installation section in the simple interchange to minimize the downsides associated with the application of the extremely strict criteria. The proposed road connection rule improvement measures based on the consideration of the purpose of installing the simple interchange and on the consideration the features of the simple interchange are expected to prevent administration confusion by the field road management offices as well as the waste of unnecessary efforts and costs by petitioners so they can boost the service satisfaction for people and the administrative reliability.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.249-257
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• 2018

The number of deaths for railway traffic accidents is mainly caused by working close to the track, or when unauthorized passage pass through the track. The safety fences are being used to ensure safety for workers close to the track, and to improve the efficiency of the work, without interfering with the passage of trains. However, a safety fence for railway tracks needs to be examined to see if it will interfere with the passage of trains. The purpose of this study is to analyze the safe distance between train and safety fence developed in Korea. In addition, the lateral load condition of wind pressure by trains is estimated and numerical analysis is carried out according to the installation intervals of railway safety fences. It has been confirmed that the proper spacing between the train and the railway safety fence should be at least 200 mm from the vehicle limit, and that the proper spacing of railway safety fence must be calculated in consideration of the wind pressure by trains.

• Journal of The Geomorphological Association of Korea
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• v.19 no.3
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• pp.143-151
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• 2012

The tsunami disasters and tectonic movements derived from mega-earthquake(M 9.0) which occured in the sea floor of the Pacific side of northeast Japan in March, 2011 were investigated. Landward invasion limit of the tsunami was 4.0km from the present coastline in Sendai coastal plain. It was observed that sandy deposit was dristributed largely in coastward part and muddy deposit was distributed largely in landward part. The ratios of distribution distances of the above two deposits were, respectively, 60~75% and 25~40% of the whole invasion distance of the 2011 tsunami. The ratios of the above distribution distances of tsunami deposits could be used to estimate landward invasion distances of the past maga-tsunamies(e.g. '2,000year B.P. Mega-Tsunami' and 'Jogan Tsunami' etc.) in Sendai coastal plain. The mega-scale tsunami disasters were caused by the low and flat geomorphic condition in the Sendai coastal plain and the increasing effect of tsunami height affected by narrow inlet condition of the so-called Ria's coast in the Sanriku coastal area respectively. Tectonic subsidences caused by the mega-earthquake in march, 2011 were observed in many areas of Ishinomaki, Ogawa, Ogachi and Onagawa coasts in northeast Japan. The displacements of tectonic subsidence were between 0.5 meters and 1.0 meters.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.2
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• pp.29-38
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• 2021

The Internet including mobile networks is developing to overcoming the limitation of physical distance and providing or acquiring information from remote locations. However, the systems that use video as primary information require higher bandwidth for recognizing the situation in remote places more accurately through high-quality video as well as lower latency for faster interaction between devices and users. The emergence of the 5th generation mobile network provides features such as high bandwidth and precise location recognition that were not experienced in previous-generation technologies. In addition, the Mobile Edge Computing that minimizes network latency in the mobile network requires a change in the traditional system architecture that was composed of the existing smart device and high availability server system. However, even with 5G and MEC, since there is a limit to overcome the mobile network state fluctuations only by enhancing the network infrastructure, this study proposes a high-definition video streaming system in ultra-low latency based on the SRT protocol that provides Forward Error Correction and Fast Retransmission. The proposed system shows how to deploy software components that are developed in consideration of the nature of 5G and MEC to achieve sub-1 second latency for 4K real-time video streaming. In the last of this paper, we analyze the most significant factor in the entire video transmission process to achieve the lowest possible latency.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.3
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• pp.29-39
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• 2021

This study interpreted a traditional garden of Korea through reception aesthetics. The 'gap' of acceptable aesthetics is found in the 'distance that occurs between writers and readers'. This study aims to interpret this gap between what the writer intends and what the reader expects. Boundaries do not limit traditional spaces in Korea and, therefore, are not limited by characteristics. These characteristics were studied from the perspectives of the author, the work, and the reader. The aspect first looked at the life and ideas of the gardener, the second analyzed the form and structure of the garden, and the last examined writings, from the past and present, of those who appreciated the garden. From the author's perspective, Sosoewon was understood as a garden that embodied the philosophy of Yang Sanbo. Second, the duality and indeterminateness were recognized as two characteristics of this work; artifacts in the garden were arranged in a natural form, and the gardens have indefinite boundaries, so they can be freely expanded and reduced. Finally, from the reader's perspective, it was noted that the beauty of this garden is enhanced through poetry, painting, and writing. Thus, historic gardens of Korea can be open spaces where the meaning of the garden is enriched through the free participation of viewers based on their own ideas.

• Journal of Internet Computing and Services
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• v.23 no.3
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• pp.47-56
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• 2022

The safe driving reward system aims to reduce the loss of life and property by reducing the occurrence of accidents by motivating safe driving and encouraging active participation by providing direct reward to vehicle drivers who have performed safe driving. In the case of the existing digital tachograph, the goal is to limit dangerous driving by recording the driving status of the vehicle whereas the safe driving reward system is a support measure to increase the effect of accident prevention and induces safe driving with financial reward when safe driving is performed. In other words, in an area where accidents due to speeding are high, direct reward is provided to motivate safe driving to prevent traffic accidents when safe driving instructions such as speed compliance, maintaining distance between vehicles, and driving in designated lanes are performed. Since these safe operation data and reward histories must be managed transparently and safely, the reward evidences and histories were constructed using the closed blockchain Hyperledger Fabric. However, while transparency and safety are guaranteed in the blockchain system, low data processing speed is a problem. In this study, the sequential block generation speed was as low as 10 TPS(transaction per second), and as a result of applying the acceleration function a high-performance network of 1,000 TPS or more was implemented.

• Journal of radiological science and technology
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• v.45 no.5
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• pp.449-455
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• 2022

This study is to present a Geant4 code for the simulation of the absorbed dose distribution given by a medical linac for 6 MV photon beam. The dose distribution was verified by comparison with calculated beam data and beam data measured in water phantom. They were performed for percentage depth dose(PDD) and beam profile of cross-plane for two field sizes of 10 × 10 and 15 × 15 cm². Deviations of a percentage and distance were obtained. In energy spectrum, the mean energy was 1.69 MeV. Results were in agreement with PDD and beam profile of the phantom with a tolerance limit. The differences in the central beam axis data 𝜹₁ for PDD had been less than 2% and in the build up region, these differences increased up to 4.40% for 10 cm square field. The maximum differences of 𝜹₂ for beam profile were calculated with a result of 4.35% and 5.32% for 10 cm, 15 cm square fields, respectively. It can be observed that the difference was below 4% in 𝜹₃ and 𝜹₄. For two field sizes of 𝜹_50-90 and RW₅₀, the results agreed to within 2 mm. The results of the t-test showed that no statistically significant differences were found between the data for PDD of 𝜹₁, p>0.05. A significant difference on PDD was observed for field sizes of 10 × 10 cm², p=0.041. No significant differences were found in the beam profile of 𝜹₃, 𝜹₄, RW₅₀, and 𝜹_50-90. Significant differences on beam profile of 𝜹₂ were observed for field sizes of 10 × 10 cm², p=0.025 and for 15 × 15 cm², p=0.037. This work described the development and reproducibility of Geant4 code for verification of dose distribution.