• Journal of the Korean Solar Energy Society
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• v.31 no.3
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• pp.1-7
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• 2011

In the performance test for wind turbines of medium and large, The reference met-mast should be installed for measurement reference wind speed as IEC 61400-12-1 standards and design of booms for mounted an anemometer must be considered exactly. Boom-mounted cup anemometer are influenced by flow distortion of the mast and the boom. Therefore design of booms must be important so that flow distortion due to booms should be kept below 0.5%. But, in some cases at size of met-mast structure, the distance of boom from mast is longer then measurement of wind speed is impossible because of oscillation of boom-mounted anemometer. In this paper, We measured a wind speed at several point from mast and boom and we analyzed the error of wind speed at each point of measurement. Also, we will suggest a correction method using the data curve fitting about errors of wind speed between each point of mounted anemometer.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.2
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• pp.648-661
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• 2019

Thin fabric-based yacht sails have a cambered shape to generate lift force; however, their shape can be easily deformed by wind pressure and also affected by the deformation of the mast. These deformations can change the airflow characteristics over the sail. Therefore, Fluid-Structure Interaction (FSI) analysis is needed to evaluate the sail force precisely. In this study, airflow over the deformed sail and rig was studied using FSI. Elastic deformation of the sail and rig was obtained by an aerodynamic calculation under dynamic pressure loading on the sail surface. The effects of rig deformation on the aerodynamic performance of the sail were examined according to the rig type and mast flexibilities. As a result, the changes of lift force for a fractional type rig with a thin mast section were more significant than with a masthead rig.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.255-255
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• 1996

Flavonoids are the large class of plant-derived polyphenolic compounds with a broad spectrum of biological actions including anti-inflammatory, anti-allergic and anti-asthmatic activities. It has been reported that quercetin and some other flavonoids inhibit the histamine release from mast cells. Disodium cromoglycate, a kind of biflavonoid, have been used as a anti-asthmatic agent. Therefore, the following study was undertaken to characterize tile structure-activity relationships of flavonoids in the inhibition of histamine release, from IgE-sensitized mast cells. Flavonoid acetate were synthesized by addition of acetic anhydride to the flavonoids dissolved in pyridine. According In the Mota method, IgE-rich serum was made in rats sensitized with Pertussis vaccine and ovalbumin. Rat abdominal mast cells were harvested and purified over tile discontineous Percoll gradients, Mast cells were preincubated in RPMI with IgE-rich serum and further incubated with flavonoids. Histamine contents released from mast cells were determined fluorospectrophotometrically after stimulation with ovalbumin. (omitted)

• Journal of Ocean Engineering and Technology
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• v.33 no.1
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• pp.50-60
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• 2019

Recently, problems with excessive vibration of the radar masts of large bulk carriers and crude oil tankers have frequently been reported. This paper explores a design method to avoid the resonance of a radar mast installed on a large ship using various design of experiment (DOE) methods. A local vibration test was performed during an actual sea trial to determine the excitation sources of the vibration related to the resonant frequency of the radar mast. DOE methods such as the orthogonal array (OA) and Latin hypercube design (LHD) methods were used to analyze the Pareto effects on the radar mast vibration. In these DOE methods, the main vibration performances such as the natural frequency and weight of the radar mast were set as responses, while the shape and thickness of the main structural members of the radar mast were set as design factors. From the DOE-based Pareto effect results, we selected the significant structural members with the greatest influence on the vibration characteristics of the radar mast. Full factorial design (FFD) was applied to verify the Pareto effect results of the OA and LHD methods. The design of the main structural members of the radar mast to avoid resonance was reviewed, and a normal mode analysis was performed for each design using the finite element method. Based on the results of this normal mode analysis, we selected a design case that could avoid the resonance from the major excitation sources. In addition, a modal test was performed on the determined design to verify the normal mode analysis results.

• Wind and Structures
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• v.38 no.3
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• pp.215-229
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• 2024

Guyed mast structures exhibit characteristics such as high flexibility, low mass, small damping ratio, and large aspect ratio, leading to a complex wind-induced vibration response mechanism. This study analyzed the time- and frequency-domain characteristics of the wind-induced response of a guyed mast structure using measured acceleration response data obtained from the Shenzhen Meteorological Gradient Tower (SZMGT). Firstly, 734 sets of 1-hour acceleration samples measured from 0:00 October 1, 2021, to 0:00 November 1, 2021, were selected to study the vibration shapes of the mast and the characteristics of the generalized extreme value (GEV) distribution. Secondly, six sets of typical samples with different vibration intensities were further selected to explore the Gaussian property and modal parameter characteristics of the mast. Finally, the modal parameters of the SZMGT are identified and the identification results are verified by finite element analysis. The findings revealed that the guyed mast vibration shape exhibits remarkable diversity, which increases nonlinearly along the height in most cases and reaches a maximum at the top of the tower. Moreover, the GEV distribution characteristics of the 734 sets of samples are closer to the Weibull distribution. The probability distribution of the structural wind vibration response under strong wind is in good agreement with the Gaussian distribution. The structural response of the mast under wind loading exhibits multiple modes. As the structural response escalates, the first three orders of modal energy in the tower display a gradual increase in proportion.

• Fashion & Textile Research Journal
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• v.9 no.5
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• pp.569-572
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• 2007

The effectiveness of Palmarosa, Neroli and Jasmin blending oil on dry skin of rat induced by kitchen detergent are investigated. The experimental groups were divided the control group, group treated with surfactant, group treated with Palmarosa and Neroli, and group with Palmarosa, Neroli and Jasmin. Observation of epidermis and the alteration of mast cell were performed with photomicroscope. According to the epidermis morphological changes analysis, the A3 group treated with Palmarosa, Neroli and Jasmin blending oil was appeared the most similar with the control group, and the A2 group applied with Palmarosa and Neroli blending oil was sequently displayed similar characteristics. The collagen layer's breakaway resulting from Palmarosa essential oil, the collagen layer's restoration resulting from Neroli essential oil, the collagen layer's retention hyperkeratosis resulting from Jasmin essential oil were observed in the structure of the epidermal layer. In photomicrosope observation of mast cell to examine the inflammatory reactions, the increase in size and number of mast cell were showed in A1 group treated with surfactant compared to the control group. The number of mast cells definitely decreased in groups which were treated with Palmarosa, Neroli and Jasmin blending oil.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.123-123
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• 2019

Xanthone is a kind of polyphenolic compounds that contain a distinctive chemical structure with a tricyclic aromatic ring found in a few higher plant families e.g. gentian root. This compound had a variety of biological activity, for instance antioxidant, antibacterial, anti-inflammatory, and anticancer effects. However, the effect of xanthone on mast cell-mediated allergic inflammation and its associated mechanism have not been elucidated. Therefore, the aim of this study was to elucidate the anti-allergic inflammatory effects and the underlying molecular mechanism of xanthone in PMACI-stimulated human mast cells-1 (HMC-1). In this result, xanthone treatment decreased the production of histamine, pro-inflammatory cytokines such as tumor necrosis factor-a (TNF-${\alpha}$), IL-6, and IL-8 and expressions of TSLP in PMACI-stimulated HMC-cells. In addition, xanthone significantly suppressed the phosphorylation of MAPKs and the activation of NF-${\kappa}B$ signal pathway in activated mast cells. Furthermore, xanthone inhibited the activation of caspase-1, an IL-$1{\beta}$ converting enzyme, in PMACI-stimulated HMC-1 cells. These findings provide evidence that xanthone could be a potential therapeutic agent for allergy-related inflammatory disorders.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.5
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• pp.638-645
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• 2020

The mast is the highest structure in a naval ship, and various communication and radar antennas are installed to achieve long-range communications and line of sight. The U.S. and European navy currently are adopting integrated mast to their new ships, as it can reduce the Radar Cross Section(RCS) of the new ships and thus improve survivability of the ship. In this paper, when other navies adopt integrated masts on new ships, types of antennas, according to the cases that the antennas are integrated on the integrated mast or not, are analyzed. Also the types of antennas and transmission techniques for the radio communication equipments of the Korean Navy are analyzed in various frequency bands. For adopting an integrated mast on Korean new ships, the effects of the ship RCS according to the types of antennas, the possibility of integration the antennas and the integrated mast and considerations were presented.

• The Journal of Korean Institute of Information Technology
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• v.16 no.11
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• pp.51-59
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• 2018

The Multi-Mission Unmanned Surface Vehicle(MMUSV), which is manufactured using glass Fiber Reinforced Plastic(FRP) material, is designed to perform a surveillance and reconnaissance on the sea. Various navigation sensors, such as RADAR, RIDAR, camera, are mounted on a mast to perform an autonomous navigation. And a dummy gun is mounted on the deck of the MMUSV for a target tracking and disposal. It is necessary to analyze a strength for structures mounted on the deck because the MMUSV performs missions under a severe sea state. In this paper, a strength analysis of the mast structure is performed on static loads and lateral external loads to verify an adequacy of the designed mast through a series of simulations. Based on the results of captive model tests, a strength analysis for a heave motion of the mast structure is conducted using a simulation tool. Also a simulation and fatigue test for a mounting part between the MMUSV and the dummy gun are performed using a specimen. The simulation and test results are represented that a structure of the mast and mounting part of the dummy gun are appropriately designed.he impact amount are performed through simulation and experiments.

• Wind and Structures
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• v.18 no.2
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• pp.181-194
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• 2014

A major problem with high-mast light poles is the effects that wind vortex shedding can have on the pole itself because of the lock-in phenomenon. It is desired that the coefficients in the AASHTO Standard Specifications ($5^{th}$ edition) for Structural Supports for Highway Signs, Luminaries, and Traffic Signals be analyzed and refined. This is for the belief that the span of the shapes of poles for which the coefficients are used is much too broad and a specific coefficient for each different shape is desired. The primary objective of this study is to develop wind vortex shedding coefficient for a multisided shape. To do that, an octagonal shape was used as the main focus since octagonal cross sectioned high-mast light poles are one of the most common shapes in service. For the needed data, many wind parameters, such as the static drag coefficient, the slope of aerodynamic lift coefficient, Strouhal number, the lock-in range of wind velocities producing vibrations, and variation of amplitude of vortex-induced vibration with Scruton number are needed. From wind tunnel experiments, aerodynamic parameters were obtained for an octagonal shape structure. Even though aerodynamic coefficients are known from past test results, they need to be refined by conducting further wind tunnel tests.