• Journal of the Society of Naval Architects of Korea
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• 제42권6호
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• pp.601-607
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• 2005

This paper describes a hydrodynamic modelling study based on the Feldman's equation to predict the nonlinear and coupled maneuvering characteristics of high speed submarine. The hydrodynamic coefficients set is obtained from the modeling of the cross flow drag force and sail induced vorticity, and the captive model experiments(VPMM and RA test) results used to improved the accuracy. The results contained in this paper will be helpful to predict the behavior of tight turn maneuver and to improve the SOE(Safety Operational Envelope) analysis in case of emergency maneuver.

• Transactions of the Korean Society of Automotive Engineers
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• 제12권1호
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• pp.174-183
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• 2004

A program to analyze the performance characteristics of a hydraulic shimmy damper for automotive steering system was developed in this study. Dimensionless mathematical equations of the dynamics of shimmy damper for forward and reverse fluid flows were derived respectively and incorporated into the Simulink models. The program was validated by comparing the results of simulation and experiments for various frequencies of upstream ripple pressures into the damper. Low-pass filter characteristics of the shimmy damper at reverse flow was demonstrated which means that the shimmy damper could alleviate the high speed ripple pressures induced by the unbalance oscillation of tire in vehicle driving. The parameter sensitivity analysis was also conducted to identify the dominant parameters for the damper performance.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 한국추진공학회 2004년도 제23회 추계학술대회 논문집
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• pp.57-61
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• 2004

As a kind of application of laser propulsion, air-breathing laser-spike engine can be designed for aircraft in atmospheric flight. Laser-spike engine generates thrust using the blast wave induced by laser energy instead of combustion process. And this engine use air as propellant, therefore, it need no on board propellant. For experimental study, supersonic wind tunnel and spark generator were used. Flow visualization was performed using 2-dimensional laser-spike engine model And numerical simulation of the corresponding case for the experiment was done and compared with experimental case. Detailed results will be discussed at the presentation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.291-291
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• 2013

The interior vehicle noise due to the exterior aerodynamic field is an important topic in the acoustic design of a car. The air flow detached from the A-pillar and impacting the side windows are of particular interest as they are located close to the driver / passenger and provides a lower insulation index than the trimmed car body parts. HMC is interested in the numerical prediction of this aerodynamic noise generated by the car windows with the final objective of improving the products design and reducing this noise. The methodology proposed in this paper relies on two steps: the first step involves the computation of the exterior flow and turbulence induced non-linear acoustic field using the CAA(Computational aeroacoustics) solver CAA++. The second step consists in the computation of the vibro-acoustic transmission through the side window using the finite element vibro-acoustic solver Actran. The internal air cavity including trim component are included in the simulation. In order to validate the numerical process, an experimental set-up has been created based on a generic car shape. The car body includes the windshield and two side windows. The body is made of aluminum and trimmed with porous layers. First, this paper describes the method including the CAA and the vibro-acoustic models, from the boundary conditions to the different components involved, like the windows, the trims and the car cavity is detailed. In a second step, the experimental set-up is described. In the last part, the vibration of the windshield and windows, the total wind noise level results and the relative contributions of the different windows are then presented and compared to measurements. The influence of the flow yaw angle (different wind orientation) is also assessed.

• Journal of Physiology & Pathology in Korean Medicine
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• 제38권1호
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• pp.16-21
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• 2024

Haepyoijin-tang and its main components have been used for phlegm, cough and dyspnea. Using a respiratory inflammation model, we intend to reveal the anti-inflammatory effect and pharmacological mechanism of Haepyoijin-tang. We induced the respiratory inflammation model by Aspergillus oryzae protease and ovalbumin administration. Female Balb/c mice (8 weeks old) were classified into four groups as follows: saline control group, aspergillus oryzae protease and ovalbumin induced respiratory inflammation group (vehicle), inflammation with Haepyoijin-tang (200 mg/kg) administration group, inflammation with dexamethasone (5 mg/kg) administration group (n=7). To identify the anti-inflammatory effects of Haepyoijin-tang water extracts, we measured the inflammatory cell number in bronchoalveolar lavage fluid (BALF) and total live lung cell number. In addition, we checked eosinophil ratio and number in BALF. And Interleukin (IL)-5 level was also measured in lung cell culture supernatant. To confirm the mechanism of anti-inflammatory effects, we analyzed the activated helper T cell (CD4⁺CD25⁺ cell) and Th2 cell (CD4⁺GATA3⁺ cell) ratio and number in lung by using flow cytometry. Finally, we attempted to confirm the immune mechanism by measuring the ratio and number of regulatory T cells (CD4⁺Foxp3⁺ cell). Haepyoijin-tang extracts treatment diminished inflammatory cell, especially, eosinophil number in BALF and total live lung cell number. Moreover, IL-5 level was reduced in Haepyoijin-tang treated group. Surprisingly, Haepyoijin-tang extracts administration not only decreased the activated helper T cell but also Th2 cell population in lung. Additionally, regulatory T cell population was increased in Haepyoijin-tang administration group. Our findings proved that Haepyoijin-tang extract have anti-inflammatory efficacy by suppressing Th2 cell activation and promoting regulatory T cell population.

• 대한공업교육학회지
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• 제34권1호
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• pp.238-251
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• 2009

The noise itself that affects the sensor array is defined as the noise which happens in the place where the system is installed and the circumference noise which comes from the ocean. The array structure for detecting acoustic signal in the underwater effected turbulent layer flow noise. In this paper to design the conformal array spectral density function was introduced and several cases of flow induced noise which affect transfer function were simulated. Modified Corcos wall pressure model was used as turbulent boundary layer flow noise. The effect of noise has been reduced as integrated sum of transfer function has been reduced by decreasing elastomer thickness and density when kx is in low wave number area. Also the characteristics of transfer function by Corcos wall pressure displayed the product of frequency density function. This simulation results can be applied to the conformal array design in unmmaned underwater vehicle in the near future.

• The Journal of Korean Medicine
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• 제34권2호
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• pp.20-28
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• 2013

Objectives: This study examined the effects of 8 types of herbal prescriptions prescribed to alleviate dementia symptoms in a rat model of arterial thrombosis induced by ferric chloride ($FeCl_3$). Methods: Thirty minutes before 35% $FeCl_3$ treatment, SD rats were intraperitoneally injected with the 8 types of herbal prescriptions, respectively. We tested the effects of the herbal prescriptions on time to occlusion (TTO) in an arterial thrombosis model using a laser Doppler flow meter. In addition, thrombus weight (TW) and collagen fiber damages were evaluated in the same condition. Results: Herbal prescriptions showed the following rank-order based on their TTO: Chong-myung-tang (CMT) > modified Jangwonhan 02 (LMK02) > Toki-shakuyaku-san (TSS) ${\geq}$ Oren-gedoku-to (OGT) ${\geq}$ Yokukansan (YKS). In particular, CMT (100 mg/kg, i.p.) and LMK02 (100 mg/kg, i.p.) delayed the TTO the most ($14.83{\pm}0.98$ and $13.67{\pm}1.03$ min, respectively) compared with the vehicle group ($7.95{\pm}0.78$ min, P<0.001). In addition, CMT, LMK02, and OGT treatment ($0.63{\pm}0.01$, $0.66{\pm}0.02$ and $0.67{\pm}0.01$ mg/mm, respectively) significantly reduced thrombus weight compared with the vehicle treatment ($0.78{\pm}0.03$, P<0.001) and also alleviated collagen fiber damage (CMT; $28.40{\pm}2.22$%, LMK02; $30.79 {\pm} 4.07$%, OGT; $26.20{\pm}1.48$%) in the vessels injured by $FeCl_3$. Therefore, CMT and LMK02 showed the greatest preventive activity in rat model of arterial thrombosis induced by $FeCl_3$. Conclusions: These results provide experimental evidence for traditional use of herbal prescriptions, suggesting that CMT and LMK02 extracts could be used to prevent vascular injury and thrombosis in the early stages of dementia.

• Journal of Ocean Engineering and Technology
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• 제24권4호
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• pp.23-31
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• 2010

The flow around a remotely-operated vehicle (ROV) has been investigated numerically to improve the resistant performance by modifying the hull form of the ROV. In the case of the base hull form considered in this study, form drag rather than friction drag was the dominant component of total drag. Subsequently, the surfaces that were most susceptible to local pressure effects were modified to give them a more streamlined shape. Eleven different hull forms were chosen to undergo surface modification for drag reduction. In addition, four different boat-tail appendages with different slant angles were installed at the stern to reduce the wake vortices that are induced by the local regions of very low pressure. Consequently, a total of 11 different hull forms for drag reduction were considered. The final hull form, which combined the hull for which surface modification resulted in the lowest drag with a boat-tail appendage with a 15-degree slant angle, resulted in a drag reduction of 20%.

• Korean Journal of Clinical Pharmacy
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• 제7권1호
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• pp.33-39
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• 1997

Cardiac and antihypertensive effects of BMS-180448, a cardiac-selective ATP-sensitive potassium channel opener, and its newly synthesized derivatives KR-31281, KR-31282 and KR-31299 were evaluated in isolated perfused rat hearts (25 min global ischemia/30 min reperfusion) and conscious rats. Three new compounds $(10\;{\mu}M)$ induced positive inotropism as evidenced by increased LVDP (left ventricular developed pressure) and RPP (Rate-Pressure Product) in nonischemic rat heart. HR-31299 increased CF (coronary flow) and HR (heart rate) but the other two had no effects. KR-31282, KR-31281 and HR-31299 had a tendency to increase reperfusion LVDP and RPP compared with vehicle, while the latter two significantly reduced reperfusion EDP with a tendency to inclose TTC (time to contracture). All three KR-compounds had very weak effects on MBP and HR in conscious rats. These results indicate that KR-31281 and HR-31299 may have some cardioprotective effects, although weaker than BMS-180448, and their mode of action different from that of BMS-180448, despite the similarity in major structural moeity.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.195-200
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• 2010

Numerical investigation was conducted to study the effects of after-body configurations and nozzle lip on the PIFS(Plume Induced Flow Separation) and eat flux to the base face. Two dimensional and axi-symmetric non-equilibrium Navier-Stoke's solver with $k-{\omega}$ SST turbulence model was used to solve the launching vehicle type configuration with propulsive jet. The experimental result of Robert J. McGhee was compared with our computational results for code validation. Three types of the after-body configurations (Straight, Boat-tail, Flare type) were simulated for this study. And the nozzle lip effect was studies using the three types of base configurations same simulation conditions. As a result of numerical investigations, higher pressure ratio condition and boat-tail after-body configuration caused severe PIFS phenomenon but the flare type after-body configuration and low pressure ratio suppressed PIFS. Flare type after-body configuration and low pressure ratio case reduced heat flux to base face. The nozzle lip dispersed the heat flux widely along the base face and the nozzle lip.