• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1546-1551
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• 2004

The laser Doppler technique is well-established as a velocity measurement technique of high precision for flow velocity. Recently, the laser Doppler technique has also been used to measure acceleration of fluid particles. Acceleration is interesting from a fluid mechanics point of view, since the Navier Stokes equations, specifically the left-hand-side, are formulated in terms of fluid acceleration. Further, there are several avenues to estimating the dissipation rate using the acceleration. However such measurements place additional demands on the design of the optical system; in particular fringe non-uniformity must be held below about 0.0001 to avoid systematic errors. Relations expressing fringe divergence as a function of the optical parameters of the system have been given in the literature; however, direct use of these formulae to minimize fringe divergence lead either to very large measurement volumes or to extremely high intersection angles. This dilemma can be resolved by using an off-axis receiving arrangement, in which the measurement volume is truncated by a pinhole in front of the detection plane. In the present study an optical design study is performed for optimizing laser Doppler systems for fluid acceleration measurements. This is followed by laboratory validation using a round free jet and a stagnation flow, two flows in which either fluid acceleration has been previously measured or in which the acceleration is known analytically. A 90 degree off-axis receiving angle is used with a pinhole or a slit.

• Journal of Energy Engineering
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• v.11 no.3
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• pp.276-282
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• 2002

The process of energy separation in a low Pressure vortex tube with compressed air as a work-ing medium is studied in detail. Experimental data of the temperature of the cold and hot air leaving the vortex tube are presented. The variation of the maximum wall temperature along the inner surface of the vortex tube and the temperature distribution in a vortex tube provide useful information about the location of the stagnation point of the flow field at the axis of the vortex tube. Analysis of the results enabled to find the optimum length of the vortex tube, the optimum shape of the Throttle and the usefulness of the Sleeve. In this study Outer tube is used for the exhaust application. The hot gas flow is turned 180$^{\circ}$and passes the out-side of the vortex tube a second time heating it. From this geometric setup of a vortex tube He effects of energy separation and the prediction of the ignition of Diesel Soot is presented by experimental data.

• Journal of Energy Engineering
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• v.11 no.1
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• pp.26-33
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• 2002

In this paper, incompressible and compressible flow characteristics around the butterfly valve have been investigated. In order to simplify the problem, a flat disk valve with various valve disk angles and pressure ratios is considered in the present calculations. It was found that as the disk angle increases, the stagnation point on the front surface of the disk moves to the center of the surface and the inflow velocity decreases. The maximum flow velocity occurs at the downstream of throat because of the formation of vents contracta. As the pressure ratio decreases, compressibility effects increase and the jet formed between the throttle body wall and the disk edge becomes supersonic. This flow also builds up as a shock cell structure. The increase of disk angle and pressure ratio makes the mass flow at the inlet decrease, while the increase of disk angle and the decrease of pressure ratio make the pressure loss coefficient increase.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.5
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• pp.1285-1290
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• 2004

From a view point of Hyungsang medicine a study is made on depressive syndromes through 'Donguibogam(東醫寶鑑)' ,'Clinical lectures by Mr. Jeesan(芝山先生 臨床學特講)' and other literature. Depressed energy(?) originally meant the disorder of vital energy in the circulation of nature with the lapse of time. In later, it has been changed to mean the disease of man, especially related to the mind. Depressive syndromes come from the stagnation of the Ki or the abnormal circulation(rising, falling, coming and going), which happens when man cannot adjust oneself to the circumstances due to the disharmony between internal and external conditions. Depressive syndrome easily attacks the following types of persons; Dam type person with excessive Ki and deficient Hyung(形), manly woman, womanly man, Bird type person who shows a great variety of emotion, Turtle type person declined to melancholy, Ki type person apt to be depressive, and Shin type person with upward gush of the fire. It also attacks the persons who have smudgy face with the scar between eyebrows, those whose pulses are mixture of two different kinds and those whose pulses extend on two ranges in Jeesan's diagram. Depressive syndromes recorded in 'Donguibogam' are globus hystericus, chest congestion, gastric discomfort, cough and asthma caused by depressed Ki, abdominal mass, edema, and tympanites. The most effective prescriptions for depressive syndromes are Eajintang(二陳湯), Guibitang(歸脾湯), Hyangsosan(香蘇散), and Gamisachiltang(加味四七湯).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.5
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• pp.668-676
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• 2003

The effect of nozzle height on heat transfer of a hot steel plate cooled by an impinging liquid jet is not well understood. Previous studies have been based on the dimensionless parameter z/d. To test the validity of this dimensionless parameter and to investigate gravitational effects on the jet, stagnation velocity of an impinging liquid jet were measured and the cooling experiments of a hot steel plate were conducted for z/d from 6.7 to 75, and an inverse heat conduction method is applied for the quantitative comparison. Also, the critical instability point of a liquid jet was examined over a range of flow rates. The experimental velocity data for the liquid jet were well correlated with the dimensionless number 1/F $r_{z}$$^2$based on distance. It was thought that the z/d parameter was not valid for heat transfer to an impinging liquid jet under gravitational forces. In the cooling experiments, heat transfer was independent of z when 1/F $r_{z}$$^2$< 0.187(z/d = 6.7). However, it was found that the heat transfer quantity for 1/F $r_{z}$$^2$=0.523(z/d = 70) is larger 11% than that in the region for 1/F $r_{z}$$^2$=0.187. The discrepancy between these results and previous research is likely due to the instability of liquid jet.uid jet.

• The Journal of Internal Korean Medicine
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• v.21 no.1
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• pp.162-168
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• 2000

Irritable Bowel Syndrome(IBS) is the most common disease in the western male, and it is founded in $70{\sim}80%$ patient who has Gastrointestinal trouble. It is characterized by the formation of disorders of Gastrointestinal tract, for example, constipation, diarrhea, abdominal pain& discomfort, stool urgency, and so on. The etiology of IBS is uncertain, but the majority of patients has emotional problems. The aims of this study are to investigate and summarize the current trends of treatment for IBS so as to suggest the effective and available way to treat this disease. In Oriental Medicine, the IBS is recognized as Stagnation of the Iiver-qi(肝氣鬱結), Incoordination between the liver and the stomach(肝胃不和). So the point of treatment of IBS is Invigorating the spleen and relieving the depression of Iiver-qi(疏肝健脾), Regulating the function of the liver and the flow of qi(調肝理氣), Regulating the stomach and lowering the adverse flow(和胃降逆), and the treatment can be approached in several ways through herb drugs, acupuncture. Some of the herb drugs have substances which promote gastric and small intestinal emptying. Acupuncture and moxibustion therapies stimulate the meridian points of LR(足厥陰肝經), ST(足陽明胃經), LI(手陽明腸經), SI(手太陽小腸經) and is reported to be effective for releafing syndromes. Anal therapy, attachment of herb drug to umbilicus are annunced as the effective treatments. So, this study of the approach and application of these treatments on IBS would be necessary.

• The Journal of Internal Korean Medicine
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• v.34 no.2
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• pp.122-133
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• 2013

Objectives : Burning mouth syndrome (BMS) is characterized by chronic pain or a burning sensation in the mouth. There is limited evidence available to provide clear guidelines for treating BMS patients and a variety of different treatments have been used. This study was designed to investigate the Effects of Korean medicine therapies on oral pain in patients with BMS. Methods : We surveyed 30 BMS patients who newly visited the Oral Diseases Clinic in the Kyung Hee University Korean Medicine Hospital from February 2012 to March 2013. When the patients visited the clinic for the first time, they were evaluated on sociodemographic characteristics, BMS questionnaire, severity of pain using visual analogue scale (VAS) and pressure pain threshold (PPT) of the acupuncture point CV17. After 3 weeks of Korean medicine therapies (acupuncture, electroacupuncture, pharmacopuncture and herbal medicine), they were re-evaluated with the VAS and the PPT. Results : After 3 weeks of Korean medicine therapies, 30 patients' oral pain improved and the PPT score on CV17 rose, which means decrease of qi-stagnation score. Conclusions : Korean medicine therapies were effective on oral pain in patients with BMS. To confirm the additional curative effect and evaluate the efficacy of each treatment, well-designed randomized controlled trials will be needed in the future.

• Journal of computational fluids engineering
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• v.14 no.1
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• pp.1-8
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• 2009

To control the coating thickness of zinc in the process of continuous hot-dip galvanizing, it is known from early days that the gas wiping through an air knife system is the most effective because of the obtainable of uniformity of coating thickness, possibility of thin coating, working ability in high speed and simplicity of control. But, the gas wiping using in the galvanizing process brings about a problem of splashing from the strip edge for a certain high speed of coating. Also, it is known that the problem of splashing directly depends upon the galvanizing speed and nozzle stagnation pressure. In theses connections, in the present study, we proposed two kinds of air knife systems having the same expansion rate of nozzle, and the jet structures and coating thicknesses from a conventional and new proposed nozzles are compared. In numerical analysis, the governing equations consisted of two-dimensional time dependent Navier-Stokes equations, standard k-e turbulence model to solve turbulence stress and so on are employed. As a result, it is found that it had better to use the constant rate nozzle from the point view of the energy saving to obtain the same coating thickness. Also, to enhance the cutting ability at the strip, it is advisable to use an air knife with the constant expansion rate nozzle.

• Journal of Physiology & Pathology in Korean Medicine
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• v.28 no.6
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• pp.585-592
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• 2014

This study is to develop a standard tool for pattern identifications in Korean Medicine for Lung Cancer. The advisor committee for this study was organized by 12 Korean Medicine professors from the Korean Association of Traditional Oncology. The item and structure of instrument were based on review of published literature. We took the consultation twice from the advisor committee and additional advices by e-mail correspondences. We divided the symptoms and signs of lung cancer into 6 pattern identifications. - lung spleen both deficiency (肺脾兩虛), lung kidney both deficiency (肺腎兩虛), dampness phlegm obstructing the lung (濕痰蘊肺), qi stagnation blood stasis (氣滯血瘀), yin deficiency toxin heat (陰虛毒熱), and heat toxin accumulation (熱毒蘊結). We obtained the mean weights which reflected the standard deviations from each symptoms of the 6 pattern identifications which were scored on a 5-point scale by 12 experts. We designed the Korean medicine pattern identification tool for lung cancer. It was composed of 57 questions in the question-and-answer format. Though there are some limits that this study is not proved about validity and reliability, the instrument is meaningful and expected to be applied to the subsequent research.

• Journal of the Korean Vacuum Society
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• v.17 no.3
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• pp.189-194
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• 2008

Measurements with a Langmuir probe, which are the most often used procedures of plasma diagnostics, can disturb plasma flows and change its characteristics quite a little because the probe should be inserted into thermal flowing plasmas. In this study, we calculated the characteristics of thermal plasmas with and without the probe into an atmospheric argon free-burning arc numerically, and investigated aerodynamic and thermal disturbances with temperature and axial velocity distributions. For the modelling of thermal plasmas, we have made two governing equations, which are on the thermal-flow and electromagnetic fields, coupled together with a commercial CFD package and user-coded subroutines. It was found that thermal disturbances happened to both sides of the probe, before and behind, seriously. Due to the aerodynamic disturbance, we could find that there were the stagnation point in front of the probe and the wake behind it. Therefore, aerodynamic and thermal disturbances caused by the probe insertion should be considered to increase the reliability of the probe diagnostics.