• 한국가시화정보학회지
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• 제18권3호
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• pp.103-108
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• 2020

RBC (red blood cell) deformability is one of factors inducing blood shear thinning effect. Reduction of RBC deformability increases blood viscosity in high shear region. In this study, 3D printed chip with proper distribution of wall shear rate (WSR) was proposed to measure RBC deformability of blood samples. To fabricate 3D printed chip, the design of 3D printed chip determined through numerical simulation was modified based on the resolution of the 3D printer. For the estimation of pressure drop in the 3D printed chip, two bypass outlets with low and high WSR are exposed to atmospheric pressure through the needles. By positioning the outlet of needles in the gravity direction, the formation of droplets at bypass outlets can be captured by smartphone. Through image processing and fast Fourier transform (FFT) analysis, the frequency of droplet formation was analyzed. Since the frequency of droplet formation is related with the pressure at bypass, high pressure drop caused by reduction of RBC deformability can be estimated by monitoring the formation of blood droplets using the smartphone.

• Asian Journal of Innovation and Policy
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• 제11권1호
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• pp.110-147
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• 2022

Many megacities are exposed to natural hazards such as earthquakes, and when located in coastal regions, are also vulnerable to hurricanes and tsunamis. The physical infrastructures of transportation systems in megacities have become so complicated that very few organizations can understand their response to extreme events such as earthquakes and can effectively mitigate subsequent economic downfalls. The technological advances made in recent years to support these complex systems have not grown as fast as the rapid demand on these systems burdened by population shift toward megacities. The objective of this paper is to examine the risks imposed on and recoveries of transportation systems in megacities as the result of extreme events such as an earthquake. First, the physical damage to transportation infrastructure, loss of the transportation system performance, and the corresponding economic loss from disruptions to passenger and freight traffic is evaluated. Then, traffic flows are re-routed to reduce vehicles' delay due to earthquakes using a microscopic traffic flow simulator with an optimization model and macroscopic terminal simulator. Finally, the economic impact of the earthquake is estimated nationwide. Southern California is regarded as the region of study. The results demonstrate the effectiveness of the integrated model and provide what and how to prepare innovative resilience policies of urban infrastructure for a natural disaster occurrence.

• Journal of Yeungnam Medical Science
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• 제39권4호
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• pp.314-321
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• 2022

Background: In this study, the degree of anxiety, depression, and stress caused by coronavirus disease 2019 (COVID-19) was identified, as well as the need for psychological prevention measures among medical students in the Daegu region that was designated the first special disaster area due to the spread of COVID-19. Methods: The subjects of this study were 318 medical students in Daegu who voluntarily participated in an online test using the Hospital Anxiety and Depression Scale and Impact of Event Scale-Revised Korean version. As a result of the test, risk students received immediate telephone counseling, and the effect of this telephone counseling was analyzed. Results: There were no differences in depression, anxiety, or stress according to gender and grade. As a result of immediate telephone counseling for risk students, significant differences were found in depression, anxiety, and stress, and the counseling was found to be effective. Conclusion: For medical students who are easily exposed to stress, the importance of psychological prevention measures and effectiveness of non-face-to-face counseling should be recognized. In the field of medical education, we must do our best to build a system that can be used immediately at the appropriate time for these programs.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2357-2363
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• 2021

Silicon carbide is widely used in radiation environments due to its excellent properties. However, when exposed to the strong radiation environment constantly, plenty of defects are generated, thus causing the material performance downgrades or failures. In this paper, the two-temperature model (2T-MD) is used to explore the defect recovery process by applying the electronic energy loss (Se) on the pre-damaged system. The effects of defect concentration and the applied electronic energy loss on the defect recovery process are investigated, respectively. The results demonstrate that almost no defect recovery takes place until the defect density in the damage region or the local defect density is large enough, and the probability of defect recovery increases with the defect concentration. Additionally, the results indicate that the defect recovery induced by swift heavy ions is mainly connected with the homogeneous recombination of the carbon defects, while the probability of heterogeneous recombination is mainly dependent on the silicon defects.

• Journal of Electrochemical Science and Technology
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• 제12권4호
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• pp.415-423
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• 2021

For a battery module where single cells are connected in series, the single cells should each have a similar state of charge (SOC) to prevent them from being exposed to an overcharge or over-discharge during charge-discharge cycling. To detect the existence of unbalanced SOC cells in a battery module, we propose a simple measurement method using a single-frequency response of electrochemical impedance spectroscopy (EIS). For a commercially available graphite/nickel-cobalt-aluminum-oxide lithium-ion cell, the cell impedance increases significantly below SOC20%, while the impedance in the medium SOC region (SOC20%-SOC80%) remains low with only minor changes. This impedance behavior is mostly due to the elementary processes of cathode reactions in the cell. Among the impedance values (Z, Z', Z"), the imaginary component of Z" regarding cathode reactions changes heavily as a function of SOC, in particular, when the EIS measurement is performed around 0.1 Hz. Thanks to the significant difference in the time constant of cathode reactions between ≤SOC10% and ≥SOC20%, a single-frequency EIS measurement enlarges the difference in impedance between balanced and unbalanced cells in the module and facilitates an ~80% improvement in the detection signal compared to results with conventional EIS measurements.

• 한국경제지리학회지
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• 제25권2호
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• pp.219-236
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• 2022

1950년대 이후 선진공업국에서 나타난 탈 공업화 현상과 1970년대의 석유위기 이후의 경제위기에서 탈피하기 위한 대안 중 하나는 첨단 신산업을 중심으로 지역혁신을 유도하는 것이었다. 미국의 실리콘 밸리, 영국의 캠브리지 등은 체계적인 계획이나 정책적 노력 없이 혁신환경이 조성된 대표적인 예라고 할 때, 옥스퍼드 지역 역시 그에 버금가는 혁신지역이라 할 수 있다. 본 연구는 옥스퍼드 지역을 대상으로 지역혁신이 언제, 어떠한 방식으로 발생하였으며, 그러한 변화과정에 영향을 미치는 요소는 무엇인지, 혁신은 어떻게 시작되었는지 등을 규명하고자 한다. 본 연구는 여러 가지 문헌자료와 인터넷 포탈 등을 검색하고 현장답사를 통한 관계자, 전문가 면담 등을 통해 수집한 자료에 근거하여 이루어졌다.

• 센서학회지
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• 제32권6호
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• pp.455-461
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• 2023

We investigated the electrical characteristics of ZnO nanoparticles (NPs) with air exposure that is a widely used electron transport layer for quantum dot light-emitting diodes (QLEDs). Upon air exposure, we observed changes in the density of states (DOS) of the trap levels of ZnO NPs. In particular, with air exposure, the concentration of deep trap energy levels in ZnO NPs decreased and electron mobility significantly improved. Consequently, the air-exposed ZnO reduced leakage current by approximately one order of magnitude and enhanced the external quantum efficiency at the low driving voltage region of the QLED. In addition, based on the excellent conductivity properties, high-brightness QLEDs could be achieved.

• 대한영상의학회지
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• 제82권6호
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• pp.1589-1593
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• 2021

류마티스 결절은 류마티스관절염의 가장 흔한 관절 외 증상이다. 류마티스 결절은 우리 몸의 어느 곳에서나 발생할 수 있지만 반복적인 외상이나 압력에 쉽게 노출되는 피하 부위에서 가장 흔하게 발생한다. 그러나 견갑하부에 자란 류마티스 결절은 보고된 바가 없었고, 이에 저자는 배부 탄성섬유종과 영상의학적으로 구분이 어려웠던 견갑하부에 발생한 류마티스 결절의 사례를 보고하고자 한다.

• 대한지리학회지
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• 제37권4호
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• pp.293-316
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• 2002

본 연구는 북한이 1991년에 처음 자유경제무역지대로 지정하여 개방한 나진-선봉지구에 대한 기초적인 지역연구의 일환으로서. 입지특성과 지역구조를 밝히는데 중점을 두었다. 3차에 걸친 현지답사와 위성사진. 그리고 관련자료를 수집하여 지난 10년간 토지이용과 지역구조 변화여부를 분석하였다. 입지적 특성인 중계기지로서의 역할은 인프라 구축 미비, 수출가공기지로서의 역할은 주변지역과 산업연계 부족 등이 문제점으로 확인되었다. 10개 계획공업구는 자체 산업구조의 취약과 공업구간의 유기적인 기능 분담이 이루어지지 않아 효율성과 잠재력이 뒤떨어지는 것으로 평가되었다. 앞으로 이 지구의 성공 여부는 북한 당국의 의지와 여러가지 입지적 문제들을 어떻게 극복하느냐에 달려 있다.

• 한국환경과학회지
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• 제19권12호
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• pp.1343-1354
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• 2010

The purpose of the study was to analyze the persistence of HCH in atmosphere, soil, sediment and water of the western and southern regions of Korea. The samples from the western region were collected from Anmyeon Island, and the samples from the southern region were collected from Kimhae and Busan. The concentration of HCH isomers in atmosphere showed the pattern of $\alpha$-HCH>$\gamma$-HCH>$\beta$-HCH. The regions with high HCH concentration in the atmosphere are the regions that have been highly exposed to HCH used in the past, and the areas that have been influenced by the long range transport. The HCH that persists in the soil, water and sediment evaporates into the atmosphere, showing the characteristics of Air-Surface exchange. When the regional concentration distributions are compared, the concentration of HCH was higher in the atmosphere of a plain and the cities near the plain, than the urban areas. In this study, the ratio of $\alpha/\beta$-HCH was used as an indicator for estimating the source of Technical HCH and Lindane. According to the result, the contribution of Lindane was high in Kimhae plain and Kimhae urban areas. However, in Busan, the contribution of Technical HCH was higher than Lindane. In case of Anmyeon Island, the western region of Korea had high contribution from Tehcnical HCH. In soil and sediment, $\beta$-HCH was dominant. In water, $\gamma$-HCH was dominant among other isomers. Such results are due to $\gamma$-HCH inLindane. Furthermore, the source of $\gamma$-HCH in urban areas is assumed to be the use of medicine, medical supplies and other living supplies. Based on the results of this study, the management of HCH, a newly list up emerging POPs, should be strengthened by further research on sources, fate, persistency, accumulation and exposures and etc. to the risk assessments.