• Journal of Ginseng Research
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• 제35권2호
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• pp.138-148
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• 2011

Exponential rise in the use of mobile communication devices has generated health concerns due to radiofrequency (RF) exposure due to its close proximity to the head. Calcium binding proteins like calretinin regulate the levels of calcium ($Ca^{2+}$) which plays an important role in biological systems. Ginseng is known for maintaining equilibrium in the human body and may play a beneficial radioprotectant role against electromagnetic field (EMF) exposure. In the present study, we evaluated the radioprotective effects of red ginseng (RG) extract in a mouse model. Calretinin (CR) expression was measured using a free-floating immunohistochemical method in the hippocampus of mice after 835 MHz EMF exposure for 5 h/d for 5 d at specific absorption rate=1.6 W/kg for the different experimental groups. The control animals were treated with NaCl while the experimental animals received 10 mg/kg ginseng, or 30 mg/kg; EMF exposed mice were also treated with NaCl, 10 mg/kg ginseng (E10), or 30 mg/kg (E30). Decreases in CR immunoreactivity (IR) along with loss of CA1 and CA3 interneurons and infragranular cells were observed in the ENaCl group while such losses were not observed in the E10 and E30 groups. CR IR significantly increased in the RG-treated group compared to control and EMF-exposed groups treated with NaCl. The study demonstrates that RG extract can serve as a radioprotective agent that maintains $Ca^{2+}$ homeostasis and prevents neuronal loss in the brain hippocampal region caused by RF exposure.

• 한국해양공학회지
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• 제31권4호
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• pp.274-280
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• 2017

Generally, global performance analysis in offshore platforms is performed using potential-based numerical tools, which neglect hydrodynamic viscous effects. In comparison with the potential theory, computational fluid dynamics (CFD) methods can take into account the viscous effects by solving the Navier-Stokes equation using the finite-volume method. The open-source field operation and manipulation (OpenFOAM) C++ libraries are employed for a finite volume method (FVM) numerical analysis. In this study, in order to apply CFD to the global performance analysis of a hull-mooring coupled system, we developed a numerical wave basin to analyze the global performance problem of a floating body with a catenary mooring system under regular wave conditions. The mooring system was modeled using a catenary equation and solved in a quasi-static condition, which excluded the dynamics of the mooring lines such as the inertia and drag effects. To demonstrate the capability of the numerical basin, the global performance of a barge with four mooring lines was simulated under regular wave conditions. The simulation results were compared to the analysis results from a commercial mooring analysis program, Orcaflex. The comparison included the motion of the barge, catenary shape, and tension in the mooring lines. The study found good agreement between the results from the developed CFD-based numerical calculation and commercial software.

• Applied Microscopy
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• 제34권2호
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• pp.103-111
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• 2004

수생식물 개구리밥(Spirodela polyrhiza)의 식물체 발달 과정에서 나타나는 미생물과의 상호관계를 주사전자현미경 및 세포학적으로 추적하여 연구하였다. 개구리밥은 부유성 식물로 분화 발달 초기부터 잠수부위에 여러 종류의 박테리아, 남조류, 규조류 등이 서식하였다. 미분화된 어린 식물체에는 성숙 발달한 식물체에 비해 미생물들이 낮은 빈도로 출현하였고, 성숙한 식물체에서는 특히 엽상체 하피에 가장 많은 미생물들이 서식하였으며, 그 다음으로는 점액성 물질이 층을 이루는 근관에 많이 관찰되었다. 반면, 신장 발달 중의 뿌리에는 일반적인 분포를 보였으며, 상피에는 미생물이 거의 분포하지 않는 양상을 보였다. 이들 미생물이 개구리밥 조직 내에 침입하여 식물체에 어떠한 영향을 미치는가를 조사하기 위해 엽상체, 연결사, 뿌리, 근관, 무성생식낭 등의 구조를 세포학적으로 추적한 결과, 어느 부위에서도 조직 내로 미생물이 침입하여 세포를 괴사시키거나 감염시키는 일은 거의 관찰되지 않았다. 그러므로, 개구리밥 식물체의 발달과정에 있어 미생물들은 어떠한 해를 주지 않는 것으로 추정된다. 이후 개구리밥에 서식하는 미생물의 질소고정치를 측정하여 그 기능을 식물체의 세포학적 측면과 접목시켜 연구하면 개구리밥과 미생물과의 상호관계가 공생적인지를 더 확실하게 밝힐 수 있을 것이다.

• International Journal of Ocean System Engineering
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• 제2권2호
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• pp.116-138
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• 2012

As in the other fields of mechanics, analytical methods represent an important analysis tool in marine hydrodynamics. The analytical approach is interesting for different reasons : it gives reference results for numerical codes verification, it gives physical insight into some complicated problems, it can be used as a simplified predesign tool, etc. This approach is of course limited to some simplified geometries (cylinders, spheres, ...), and only the case of one or more cylinders, truncated or not, will be considered here. Presented methods are basically eigenfunction expansions whose complexity depends on the boundary conditions. The hydrodynamic boundary value problem (BVP) is formulated within the usual assumptions of potential flow and is additionally simplified by the perturbation method. By using this approach, the highly nonlinear problem decomposes into its linear part and the higher order (second, third, ...) corrections. Also, periodicity is assumed so that the time dependence can be factorized i.e. the frequency domain formulation is adopted. As far as free surface flows are concerned, only cases without or with small forward speed are sufficiently simple to be solved semi-analytically. The problem of the floating body advancing in waves with arbitrary forward speed is far more complicated. These remarks are also valid for the general numerical methods where the case of arbitrary forward speed, even linearized, is still too difficult from numerical point of view, and "it is fair to say that there exists at present no general practical numerical method for the wave resistance problem" [9], and even less for the general seakeeping problem. We note also that, in the case of bluff bodies like cylinders, the assumptions of the potential flow are justified only if the forward speed is less than the product of wave amplitude with wave frequency.

• 한국물환경학회지
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• 제35권2호
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• pp.99-104
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• 2019

The objective of this study was to investigate the relationship between the biomass of cyanobacteria and the concentration of 2-methylisoborneol (2-MIB) in the lower Gongji stream. The investigation was done using a field study that was conducted from 2015 to 2017. The 2-MIB concentration in the lower Gongji stream ranged from 0 to 153 ng/L, while the upper stream had 0 2-MIB concentration. 3 genera (Oscillatoria, Phormidium, Pseudanabaena) of cyanobacteria were detected in the lower Gongji stream with 2-MIB concentration. Among these 3 genera, an increase in Phormidium, Pseudanabaena biomass was associated with an increase in 2-MIB concentration. Accordingly, Phormidium, Pseudanabaena were regarded as the biological source of 2-MIB in that area. In October 2017, although planktonic cyanobacteria occurred less frequently, many benthic cyanobacteria mats were observed on the surface of the water body. Therefore, the high 2-MIB concentration, which exceeded 110 ng/L, can likely be attributed to the benthic cyanobacteria. In a laboratory experiment, individual Oscillatoria filaments were aggregated to form a colony with a higher density. This colony tended to float on the water surface. Cyanobacteria mats after floating aggregated mats were distributed in a net shape on the bottom.

• 대한한의학원전학회지
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• 제34권4호
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• pp.27-64
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• 2021

Objectives : This paper examined the Buddhist contents within the text, Bencaoshengyabanji(本草乘雅半偈). Methods : Medicinals that were searched through Buddhist vocabulary were examined. Results & Conclusions : Medicinals that quoted the Lengyanjing were related to the Water-Fire interaction, food and medicine, and karma, while those that quoted the Shidian were related to 無上道, 去惡殺蟲, 樞機滑利, and 生生之氣. Those related to the Great Earth of the Four Elements corrected the body's form based on Metal Qi, while those related to the Great Water were connected to the circulation of water dampness. Those related to the Great Fire were deeply related to Yang Qi, and those related to the Great Wind were connected to Wind control. Of the Four Origins, medicinals that were viviparous lowered Qi, while those that were oviparous were related to communicating Shen, treating diseases of the Conception Vessel, and the closing and opening of day and night. Medicinals originating from dampness were related to urination and fluid management, while those of metamorphosis were related to the process of Qi. Those related to emptiness were related to the communication of the Qi system, while those related to 六根六塵 were connected to calming the Shen and strengthening the will, and smoothing the nine orifices. Medicinals related to 圓通 were used for improving eyesight and hearing and controlling the closing and opening. Lu Zhi-yi's analysis of medicinals through the Lengyanjing is original in that it suggested a new perspective other than previous theories on pharmacology which were based on the Yin-Yang and Five Phases and Rising/Lowering/Floating/Sinking theories, but also pedantic and exaggerated. The Bencaoshengyabanji is a unique text on medicinals which analyzed each medicinal under Buddhist influence. However, it also followed the contexts of other previous texts on medicinals, and influenced Zou shu.

• 한국입자에어로졸학회지
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• 제18권1호
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• pp.1-8
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• 2022

Since 2019, the corona virus has been continuously affect human life. In particular, in the indoor space where people live, infection by airborne transmission of viruses is a problem. Among them, the spread in the subway, which is the main mode of transport for humans, can be serious. To solve this problem, our research team developed an ionic wind collector to collect and remove corona virus using an ionic wind collector and ozone. In order to apply the ionic wind collector to the subway, it must operate in two modes. Because large amounts of ozone are harmful to the human body. There is a mode that collects bio-aerosol from the air using ionic wind and a mode that inactivates viruses floating in the air by generating a large amount of ozone. As the applied voltage increased, the cleaning ability of the ionic wind collector increased, and the farther the distance between the discharge electrode and the ground plate, the higher the cleaning ability even at low current. In addition, clean air delivery rate (CADR) of an ionic wind collector was up to 5.5 m³/min. As a result of measuring the amount of ozone generated, it was confirmed that 50 ppb to 250 ppb was generated, and it was confirmed that ozone generation was controllable in the ionic wind dust collector.

• 한국안전학회지
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• 제38권2호
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• pp.87-95
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• 2023

On October 29, 2022, a very large number of people gathered in Itaewondong, Yongsan-gu, Seoul, Korea for a Halloween festival, and as crowds pushed through narrow alleys, 159 deaths and 195 injuries occurred, making it the largest crushing incident in Korea. There have been a number of stampede deaths where crowds gathered at large-scale festivals, event venues, and stadiums, both at home and abroad. When the density increases, the physical contact between bodies becomes very strong, and crowd turbulence occurs when the force of the crowd is suddenly added from one body to another; thus, the force is amplified and causes the crowd to behave like a mass of fluid. When crowd turbulence occurs, people cannot control themselves and are pushed into he crowd. To prevent a stampede accident, investigation and management of areas expected to be crowded and congested must be systematically conducted, and related ministries and local governments are planning to establish a crowd management system to prepare safety management measures to prevent accidents involving multiple crowds. In this study, based on national data, a continuous digital topographic map is modeled in 3D to analyze the risk of crowding and present a plan for selecting high-risk walking routes. Areas with a high risk of crowding are selected in advance based on various data (numerical data, floating population, and regional data) in a realistic and feasible way, and the analysis is based on the visible results from 3D modeling of the risk area. The study demonstrates that it is possible to prepare measures to prevent cluster accidents that can reflect the characteristics of the region.

• 대한한의학회지
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• 제44권3호
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• pp.170-188
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• 2023

Objectives: The purpose of this study is to investigate the diagnostic factors of Damjeok in the literature. Methods: This study used the databases of five (Mediclassics, RISS, KMbase, OASIS, CNKI) to analyze diagnostic factors of Damjeok. Literatures published by May 2023 were assessed and we classified 91 literatures dealing with diagnostic factors by 5 categories, 'characteristics', 'location', 'symptom', 'pulse wave & tongue feature', and 'eating habits & lifestyle'. Results: Damjeok is mainly formed at the stomach in the form of lump or hard seed, and it can be observed in other regions or even the whole body by its trait of floating. Damjeok mainly shows symptoms of the digestive system and also causes various symptoms associated with the respiratory system and infection, musculoskeletal system, urogenital system, neuropsychiatric system and cardiovascular system. Regarding pulse wave and tongue feature, a slippery wave and greasy coated tongue are typical features of Damjeok. Additionally, bad eating habits and a lack of exercise have been described as a factor that cause and aggravate Damjeok. Conclusions: The two most important factors in the diagnosis of Damjeok are abdominal stiffness by physical examination and digestive symptoms, and these correspond to the definition of a syndrome. Diagnostic factors based on literature evidence will provide clues to the clinical diagnosis of Damjeok syndrome.

• 대한환경공학회지
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• 제38권7호
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• pp.387-394
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• 2016

실제 하천과 호소에서 적용된 상용화된 28개 조류저감기술의 현장적용 자료를 조사하고, 이를 평가(evaluation) 분석(analysis)하여 분류(classification)하였다. 분류 기준은 공법구분, 적용 수체의 유속, 적용 시점의 3가지 기준에 의해 분류하였으며, 각 조류저감기술은 경제성, 현장 적용성, 효과 지속성, 수생태 안전성을 기준으로 평가를 실시하였다. 공법 원리별로 분류시 물리적 공법이 32.2%, 화학적 공법이 25%, 생물학적 공법이 21.4%, 복합처리 공법이 21.4%를 차지하였다. 조사된 조류저감기술의 75%는 유속 0.2 m/s 이하의 정체된 호소, 저수지, 소형 하천을 대상으로 적용되었다. 가압부상장치와 컨베이어 벨트 및 탈수장치를 탑재한 이동식 녹조제거선과 광물기반 천연 부유응집제 기술이 타 기술 대비 현장 적용성은 우수한 것으로 조사되었다. 발생현장에 적합한(site-specific) 맞춤형 조류저감기술의 도입은 pilot 규모의 장 단기 운전을 통해 효율을 검증 후 최종 도입하는 것이 바람직하다. 또한, 회수된 조류 바이오매스를 생물 자원화를 통해 에너지 회수형 조류저감기술 등의 신속한 개발 및 보급이 필요하다.