• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.93-98
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• 2007

The air velocity flowing in inner combustion chamber of SCramjet is supersonic and the time of its stay is very short as a few milliseconds. Within this short time, fuel injection， air-fuel mixing, and combustion process should be accomplished. Several methods are suggested for mixing enhancement. Among these, cavity is selected to study for mixing characteristics. The numerical simulation is performed in the case of freestream Mach number of 2.5 and cavity located in front of fuel jet injection. 3 different sized cavities of the same length-height ratio were used in order to recognize the effect about cavity size. Also, the case without cavity was analyzed to find the effect of cavity. Used code compared with the result of experiment under identical conditions and it was verified. Through this comparison and verification, mixing enhancement by cavity size could be confirmed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.81-86
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• 2007

The air velocity flowing in inner combustion chamber of Scramjet is supersonic and the time of its stay is very short as a few milliseconds. Within this short time, fuel injection, air-fuel mixing, and combustion process should be accomplished. Several methods are suggested for mixing enhancement. Among these, cavity is selected to study for enhancement of mixing. The numerical simulation is performed in the case of freestream Mach number of 2.5 and cavity located in front of fuel jet injection. 8 different sized cavities of length-height ratio were used in order to recognize the effect about cavity size. Also, the case without cavity was analyzed to find the effect of cavity. Used code compared with the result of experiment under identical conditions and it was verified. Through this comparison and verification, mixing enhancement by cavity could be confirmed.

• Tunnel and Underground Space
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• v.30 no.4
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• pp.335-358
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• 2020

We present a numerical model to simulate coupled hydro-mechanical behavior of fault using TOUGH-FLAC simulator. This study aims to develop a numerical method to estimate fluid injection-induced fault reactivation in low permeability rock and to access the relevant hydro-mechanical stability in rock as part of DECOVALEX-2019 Task B. A coupled fluid flow and mechanical interface model to explicitly represent a fault was suggested and validated from the applications to benchmark simulations and the field experiment at Mont Terri underground laboratory in Switzerland. The pressure build-up, hydraulic aperture evolution, displacement, and stress responses matched those obtained at the site, which indicates the capability of the model to appropriately capture the hydro-mechanical processes in rock fault.

• The Journal of Korean Medicine
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• v.42 no.2
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• pp.21-30
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• 2021

Objectives: The aim of this study is to investigate the anti-inflammatory effects of Ojeok-san and compare the therapeutic effects according to its formation. Methods: We evaluated the anti-inflammatory effects of Ojeok-san using lipopolysaccharide (LPS) induced inflammatory animal model. Male SD rats were administered intra-orally with two different formulation types of Ojeok-san according to prescribed dosage. One hour later, to induce inflammatory responses, subsequent intra-peritoneal injection of LPS was conducted. After 5 hours later, serum TNF-α, IL-1β, IL-6 and PGE2 levels were measured by ELISA to assess the alteration of pro-inflammatory markers. Results: In our experiment, regardless of its formation, administration of Ojeok-san decreased TNF-𝛼, IL-1𝛽, IL-6 and PGE2 level in serum. Furthermore, LPS-induced toxicity of liver and kidney was not detected by Ojeok-san administration. Conclusions: The anti-inflammatory effect of Ojeok-san was shown in LPS-induced inflammatory model by decreasing pro-inflammatory markers, and there would be no significant difference in therapeutic effect between two formulation types of Ojeok-san.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.3
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• pp.263-278
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• 2022

This paper contains experimental study for the development and performance of TBM backfill material with thixotropic properties. The LW backfill material is widely applied to fill the cavity on the back side of the shield TBM excavation, but has disadvantages such as settlement caused by strength reduction, material separation by groundwater, and reduced plasticity. In this paper, laboratory tests and a model test were conducted to assess the performance of inorganic thixotropic backfill material proposed to improve these problems. The results of laboratory tests show that 1 hr-uniaxial compressive strength of ITB was 12 times higher than LW, and the rate of bleeding of 20 hr was 8.3 times lower, and the result of flow table test was more than 27 times higher. This result indicated that the inorganic thixotropic backfill material has superior properties to LW backfill in terms of strength reduction, material separation, and thixotropy. In the model experiment, a model injection device tester was manufactured and the injection performance and filling rate were verified. When material was injected in the water, it was visually checked whether material separation occurred, and it was confirmed that the filling rate was 96% or more. Comparison results with the test of LW and ITB materials was concluded that ITB can reduce the material separation by groundwater and the occurrence of tunnel cavity.

• Journal of Korean Physical Therapy Science
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• v.9 no.2
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• pp.111-122
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• 2002

In oriental medicine, manual-acupuncture and electroacupuncture (EA) have been widely utilized to cure several inflammatory diseases such as arthritis. We designed this experiment to find neurochemical mechanism related to electroacupuncture induced anti-inflammatory effect on mouse air pouch model. EA with both low frequency (1 Hz) and high frequency (120 Hz) was treated after induction of inflammation in air pouch using injection of zymosan. To verify the role of opioid system in electroacupuncture-induced anti-inflammatory effect, naloxone (10 mg/kg) was pretreated. In addition, idazoxan (5 mg/kg) was pre-treated to evaluate the possible effect of endogenous adrenergic system in autonomic system on EA induced anti-inflammatory effect. As results of this study, naloxone pretreatment did not change the anti-inflammatory effect evoked by high frequency EA, while low frequency EA(1 Hz) induced anti-inflammatory effect was dramatically suppressed by naloxone pretreatment. These data indicated that endogenous opioid system might be extensively involve in anti-inflammatory effect evoked by not high frequency, but low frequency EA. However, idazoxan pretreatment did not produce any modulatory effect on both low and high frequency EA induced anti-inflammatory effect, suggesting that EA induced anti-inflammatory effect was not mediated by endogenous adrenergic system. In conclusion, these data strongly suggested that EA induced anti-inflammatory effect is mediated by endogenous opioid system, not endogenous adrenergic system.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.3
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• pp.31-39
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• 1999

In this paper, numerical experiment is attempted to analyze and compare the combustion efficiency of the burning sprays due to OFO, FOF triplet / FOOF split doublet injectors. Preconditioned Wavier-Stokes equation system with low Reynolds number $\kappa$-$\varepsilon$ model for turbulence closure, is LU-SGS time-integrated. Spray processes are modeled by DSF analysis with experimentally determined injection characteristics. n-heptane/air global reaction model approximates the combustion for simplicity, and the influence of turbulence on the chemical reaction is included using eddy dissipation model. The results showed the FOF triplet injector of highest combustion efficiency, whereas the OFO type of poet performance. It was also observed that the droplet mean diameter and the average gas temperature due to the mixing efficiency, are the representative parameters for the performance design of combustion.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.8
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• pp.4051-4055
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• 2012

Functional foods include antioxidant nutrients which may protect against many human chronic diseases by combating reactive oxygen species (ROS) generation. The purpose of the present study was to investigate the protective effect of pomegranate peel extract (PPE) on azoxymethane (AOM)-induced colon tumors in rats as an in vivo experimental model. Forty Sprague-Dawley rats (4 weeks old) were randomly divided into 4 groups containing 10 rats per group, and were treated with either AOM, PPE, or PPE plus AOM or injected with 0.9% physiological saline solution as a control. At 8 weeks of age, the rats in the AOM and PPE plus AOM groups were injected with 15 mg AOM/kg body weight, once a week for two weeks. After the last AOM injection, the rats were continuously fed ad-libitum their specific diets for another 6 weeks. At the end of the experiment (i.e. at the age of 4 months), all rats were killed and the colon tissues were examined microscopically for lesions suspected of being preneoplastic lesions or tumors as well as for biochemical measurement of oxidative stress indices. The results revealed a lower incidence of aberrant crypt foci in the PPE plus AOM administered group as compared to the AOM group. In addition, PPE blocked the AOM-induced impairment of biochemical indicators of oxidative stress in the examined colonic tissue homogenates. The results suggest that PPE can partially inhibit the development of colonic premalignant lesions in an AOM-induced colorectal carcinogenesis model, by abrogating oxidative stress and improving the redox status of colonic cells.

• Journal of Haehwa Medicine
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• v.29 no.1
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• pp.1-17
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• 2020

Objectives : The objectives of this study is to develop a mouse model similar to Taeeum-type by inducing Lung fibrosis with bleomycin, and to determine adequate concentration of bleomycin. Methods : The subjects were divided into six groups: normal, obesity induced group, and bleomycin administered 0.015U, 0.03U, 0.06U, and 0.09U(U/100g bw) concentrations respectively. Each concentration of bleomycin was dissolved in distilled water, and administered through Intra-Nazal-Trachea injection method. Food intake and body weight were measured at regular time weekly. At the end of the experiment, blood was gathered by cardiac puncture for biochemical examinations, organs were removed for histological examinations, and weigh and mRNA genes was analyzed. Result : Mice administered with bleomycin at 0.015U and 0.03U showed body and fat weight gain, and increased blood total cholesterol, LDL-cholesterol, glucose, and free fatty acid level. Fat related genes also showed higher level than the control group. Obesity was most strongly induced in the mice administered with 0.03U of bleomycin. On the other hand, when bleomycin was administered at concentrations above 0.06U, a model of obesity mouse was not created due to rapid emphysema inflammation and weakness. Conclusions : Mice were most vulnerable to obesity when bleomycin was administered at a concentration of 0.3 to cause liver damage. Bleomycin concentration over 0.06U did not cause obesity-induced mice, due to severe damage in liver.

• Preventive Nutrition and Food Science
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• v.6 no.3
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• pp.176-179
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• 2001

The present study was designed to investigate the hypoglycemic activity and lipid metabolism of ethanol (EtOH) extract from the aleurone layer of anthocyanin-pigmented (AP) rice in streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley male rats weighing 210~240 g were divided into 4 groups, normal, diabetic control, and two experimental groups, and diabetes in rats was induced by injection of STZ (45 mg/kg, body weight) into tail vein. The EtOH extract of the powdered aleurone layer of AP rice was administered orally in diabetic rats for 14 days. In order to find the hypoglycemic effects in the animal model, the body weight, plasma glucose levels, cholesterol, HDL-cholesterol, triglyceride (TG), free fatty acid (FFA), aspartate aminotransferase (AST) and alanine amino- transferase activities (ALT) were determined. Oral administration of 1.0 81kg on the EtOH extract for 14 days resulted in a significant reduction in blood glucose, ALT, TG and FFA. However, in the case of 2.0 g/kg, the hypo-glycemic effects were not considerable. This results suggest that the EtOH extract might induce hypoglycemic effects in STZ-induced diabetic rats due to some photochemical components in the aleurone layer of AP rice.