• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.5 s.248
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• pp.465-471
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• 2006

Controlled auto-ignition(CAI) combustion, offers the potential to improve fuel economy and reduce emission simultaneously. In this study, CAI-combustion was achieved in a single cylinder gasoline DI engine with modified camshafts in order to restrict the gas exchange process. We investigated the effects of air-fuel ratio, residual EGR rate and injection timing such as early injection and late injection on the attainable CAI combustion region. The effect of injection timings on combustion characteristic such as start of combustion, combustion duration and heat release rate was also investigated. From the result early injection causes the mixture to ignite earlier and burn more quickly due to the exothermic reaction during the recompression and gives rise to good mixing of the fuel/air. On the other hand, late injection extended the operation region more than early injection but the emissions of HC and NOx were more or less increased than early injection.

• Korean Journal of Pharmacognosy
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• v.36 no.3 s.142
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• pp.224-228
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• 2005

Protective effects of various natural flavonoids on carbon tetrachloride $(CCl_4)-induced$ hepatotoxicity were investigated in primary cultured rat hepatocytes. Some of these flavonoids decreased the ALT and LDH releases induced by $CCl_4$ in A dose-dependent manner. Neohesperidin, hesperetin, baicalin, baicalein and quercetin inhibited $CCl_4-induced$ alanine aminotransferase (ALT) release. In addition, quercetin, quercitrin, neohesperidin, baicalin, baicalein and naringin reduced $CCl_4$ induced lactate dehydrogenase (LDH) leakage. Among these flavonoids, quercitrin, quercetin, baicalin and baicalein possessed potent protective effects and were selected for the further investigation on lipid peroxidation. These four flavonoids inhibited dose dependently $CCl_4-induced$ lipid peroxidation. Especially, the protective effects of quercetin and baicalein were similar to silybin as a well-known hepatoprotective agent. These results suggest that these four flavonoids have significant cytoprotective effects and possibility of therapeutic effect on chemical-induced liver diseases.

• Natural Product Sciences
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• v.8 no.4
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• pp.177-182
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• 2002

The effect of aqueous extract of Sanguisorba officinalis L. (Rosaceae) root (SOAE) on the immediate-type allergic reactions by anal therapy was investigated. SOAE (0.01 to 1 g/kg) dose-dependently inhibited systemic anaphylaxis induced by compound 48/80 in mice. When SOAE was pretreated at the same concentrations with systemic anaphylaxis, the plasma histamine levels were reduced in a dose-dependent manner. SOAE (0.1 and 1 g/kg) also significantly inhibited local anaphylaxis activated by anti-DNP IgE. SOAE (0.001 to 1 mg/ml) dose-dependently inhibited the histamine release from rat peritoneal mast cells (RPMC) activated by compound 48/80 or anti-DNP IgE. The level of cyclic AMP (cAMP) in RPMC, when SOAE (1 mg/ml) was added, transiently and significantly increased compared with that of basal cells. These results provide evidence that anal therapy of SOAE may be beneficial in the treatment of allergic diseases.

• Korean Journal of Acupuncture
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• v.26 no.4
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• pp.225-235
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• 2009

Objective : The purpose of this study was to report a case of a treatment with Scolopendrae Corpus Herbal-Acupuncture for one patient suffering from the Cervical Myelopathy. Scolopendrae Corpus Herbal-Acupuncture has been used as a analgesics and antispasmodics in the oriental medicine and reported to have antiinflammatory effect, sedative action and immunity enhancing activity, on one patient suffering from the Cervical Myelopathy. Methods : TThe patient was treated with Scolopendrae Corpus Herbal-Acupuncture, acupuncture, herbal medication. Scolopendrae Corpus Pharmacopuncture was administered two or three times per week and we injected 0.2~1.0 ml of Scolopendrae Corpus Pharmacopuncture to the patient's neck and both arms. The improvement of the symptoms was evaluated by JOA score(Japanese Orthopedic Association score), Nurick grading, VAS(Visual Analog Scale), reflex testing, Finger escape sign, Grip and Release test. Result : After 5 weeks of treatment, the patient's JOA score, Nurick grading and VAS were improved from 12 to 16, from grade III to grade II and from 10 to 3 respectively. The movement and power of upper and lower limbs were restored to nearly normal range.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.4
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• pp.617-624
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• 2002

An equation of J-integral for a penny-shaped crack at the end of the fiber embedded in rubber matrix is proposed. The values of J-integral for the specimens with various crack and specimen radius are obtained by FEA(Finite Element Analysis). The dimensional analysis is applied to derive an equation of J-integral as a nonlinear elastic energy release rate. The geometry and deformation calibration function in an equation of J can be expressed in a separated form. The geometry calibration function characterizing the effects of cord and specimen size is expressed in a polynomial form of fourth order. The deformation calibration function characterizes the effect of the overall level of strain. As approaching the infinitesimal strain, the value of the deformation calibration function approaches the results of LEFM(Linear Elastic Fracture Mechanics).

• Journal of Veterinary Clinics
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• v.36 no.6
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• pp.325-329
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• 2019

This study was designed to compare the effects of continuous release of an anti-glaucoma drug applied by an osmotic pump and by conventional eye drop instillation in normal beagle dogs, by measuring drug concentration in the blood and monitoring intra-ocular pressure (IOP). In group 1, an osmotic pump filled with Trusopt® was implanted subcutaneously over the right eye of each dog and the IOP was measured. In group 2, the right eye of each dog was administered with 2% dorzolamide (Trusopt®, Merck, USA) three times per day. Blood was sampled once per week in all groups. The IOP of the end of this study was 16.7 ± 0.58 mmHg in group 2 and 17.7 ± 2.52 mmHg in group 2. Dorzolamide concentration in blood increased continuously over 4 weeks up to 585.8 ± 79.42 ㎍/L in group 1, and 747.3 ± 27.89 ㎍/L in group 2. We achieved satisfactory results in the osmotic pump group, which had a similar effect on IOP, and low fluctuations in IOP. Therefore, the results of this study should allow osmotic pumps to be consider as an alternative method to eye drops for the effective, safe, and convenient treatment of glaucoma.

• Journal of Integrative Natural Science
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• v.5 no.1
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• pp.46-52
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• 2012

Mulberry extracts can be incorporated into skin-whitening products. The compound attributed to lighten the skin is arbutin, a form of hydroquinone that inhibits melanin release by suppressing the tyrosinase enzyme. For the cosmetic applications, the physiological effects of mulberry (Morus alba) extracts were investigated. The water soluble fraction of mulberry contains higher amount of protein (16.28~4.47%) in contrast to fat (1.55~1.41%). In addition, the fraction abundantly contains succinic acid (972.4-275.8 mg/g) and phosphoric acid (1,628.4-121.9 mg/g) in different parts of mulberry. The free radical scavenging ability in water soluble fraction was found to display remarkable effects in comparison with methanol and ethyl acetate fraction. The ethyl acetate-soluble of root and leaf showed remarkable tyrosinase inhibition activity by IC 50 (${\mu}g/ml$). The anticancer activity of methanol fraction obtained from mulberry using human cancer cell lines showed growth inhibition effect (270.14 mg/ml in Calu-6 cells, 295.29 mg/ml in HCT-116, and 332.29 mg/ml in MCF-7 cells, respectively). Based on the results, Morus alba extracts include cosmetic ingredients with antioxidizing and whitening properties.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.248.1-248
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• 1999

Preliminary analysis of in-reactor thermal performance of three MOX fuel rods, which are going to be irradiated in the Halden reactor beginning in the first Quarter of the year 2000 under the framework of the OECD Halden Reactor Programme, have been conducted by using the computer code COSMOS to ensure their safe operation. Parametric studies have been carried out to investigate the effect of uncertainties on in-reactor behavior by considering the four kinds of uncertainties; thermal conductivity, linear power, manufacturing parameters, and model constants. The analysis shows that, in the case of annular MOX -1 fuel, calculation results for thermal performance vary widely depending on the selection of model constants for fission gas release (FGR). On the contrary, the thermal performance of solid MOX - 3 fuel does not depend on the choice of FGR constants to a large extent as MOX-I, because the fuel temperature is very high in the MOX-3 irrespective of the choice of FGR constants and hence the capacity of grain boundaries to retain gas atoms is not large enough to accommodate the number of gas atoms reaching the grain boundaries. It is planned that when the data on microstructure and thermal conductivity for each type of MOX fuel are available, new analysis will be made using these information. In addition, FGR model constants will be derived from the measured fuel centerline temperature, rod internal pressure and other related data.

• Nuclear Engineering and Technology
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• v.42 no.4
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• pp.434-441
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• 2010

The activation products of aluminum and argon are key radionuclides for operational and environmental radiological safety during the normal operation of open-tank-in-pool type research reactors using aluminum-clad fuels. Their activities measured in the primary coolant and pool surface water of HANARO have been consistent. We estimated their sources from the measured activities and then compared these values with their production rates obtained by a core calculation. For each aluminum activation product, an equivalent aluminum thickness (EAT) in which its production rate is identical to its release rate into the coolant is determined. For the argon activation calculation, the saturated argon concentration in the water at the temperature of the pool surface is assumed. The EATs are 5680, 266 and 1.2 nm, respectively, for Na-24, Mg-27 and Al-28, which are much larger than the flight lengths of the respective recoil nuclides. These values coincide with the water solubility levels and with the half-lives. The EAT for Na-24 is similar to the average oxide layer thickness (OLT) of fuel cladding as well; hence, the majority of them in the oxide layer may be released to the coolant. However, while the average OLT clearly increases with the fuel burn-up during an operation cycle, its effect on the pool-top radiation is not distinguishable. The source of Ar-41 is in good agreement with the calculated reaction rate of Ar-40 dissolved in the coolant.

• Nuclear Engineering and Technology
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• v.52 no.5
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• pp.918-924
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• 2020

Film boiling is of great importance in nuclear safety as it directly influences the integrity of nuclear fuel in case of accidents involving loss of coolant. Recently, nuclear power plant safety under earthquake conditions has received much attention. However, to the best of our knowledge, there are no existing studies reporting film boiling in an oscillating system. Most previous studies for film boiling were performed on stationary systems. In this study, numerical simulations were performed for saturated film boiling of water on a horizontal surface under low frequencies to investigate the effect of system oscillation on film boiling heat transfer. A coupled level-set and volume-of-fluid method was used to track the interface between the vapor and liquid phases. With a fixed oscillation amplitude, overall, heat transfer decreases with oscillation frequency. However, there is a frequency region in which heat transfer remains nearly constant. This lock-on phenomenon occurs when the oscillation frequency is near the natural bubble release frequency. With a fixed oscillation frequency, heat transfer decreases with oscillation amplitude. With a fixed maximum amplitude of the additional gravity, heat transfer is affected little by the combination of oscillation amplitude and frequency.