• Geomechanics and Engineering
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• v.18 no.1
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• pp.1-9
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• 2019

In this study, both 2D and 3D failure shapes of rock mass above the water-filled cavity are put forward when the surrounding rock mass cannot bear the pressure caused by the water-filled cavity. Based on the analytical expressions derived by kinematic approach, the profiles of active and passive failure patterns are plotted. The sensitivity analysis is conducted to explore the influences of different rock parameters on the failure profiles. During the excavation of the deep tunnels above the karst cavity, the water table always changes because of progressive failure of cavity roof. Therefore, it is meaningful to discuss the effects of varying water level on the failure patterns of horizontal rock layers. The changing laws of the scope of the failure pattern obtained in this work show good consistency with the fact, which could be used to provide a guide in engineering.

• Journal of Pharmaceutical Investigation
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• v.23 no.3
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• pp.9-18
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• 1993

Sugar spheres loaded with melatonin (MT) were coated with $Aquacoat^{\circledR}$ to control the release rate of MT over 8 hours. A zero-order release pattern over 8 hours was obtained with 20% coating on 8-10 mesh beads in USP basket dissolution studies. MT in 20% coated beads was quite stable at room temperature with less than 5% MT degraded during 6 months' storage. Dissolution profiles were also unchanged after 6 months. An oral preparation containing MT-loaded uncoated beads for immediate release and 20% coated beads with $Aquacoat^{\circledR}$ for controlled release over 8 hours was evaluated in six human subjects. When total 0.5 mg MT as low dose (immediate release portion of MT, 0.1 mg) was administered to four subjects, average peak plasma MT concentration was reached at about 600 pg/ml and maintained at about 10 pg/ml over 8 hours. Plasma MT concentration-time profiles were similar in shape to computer-simulated profiles. However, maximal plasma MT concentrations were three times greater compared to computer simulated curve. These results suggest that MT dose, ratio of immediate and controlled release MT, and pharmacokinetic parameters selected are adjusted to mimic endogenous MT concentration-time curve. In another study, 0.2 mg MT having 10% of immediate release portion and 80% controlled release portion produced plasma MT concentration-time curve which is more similar to endogenous profiles. A low bioavailability (<20%) may result from extensive first pass metabolism and remaining amounts of MT from controlled beads. A good correlation between plasma MT concentration and urinary excretion rate of 6-sulphatoxymelatonin (6-STMT), a major metabolite of MT was observed. As plasma MT concentration increased, urinary excretion rate of 6-STMT increased concomitantly. The linear relation between plasma MT and urinary excretion rate of 6-STMT was statistically significant. This result suggests that urinary 6-STMT may be used as an index of circadian rhythms of MT in humans.

• Journal of the Korean Home Economics Association
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• v.46 no.5
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• pp.63-71
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• 2008

The purposes of this study were (1) to analyze the absolute and relative importance of tourists' choice attributes of restaurants and (2) to compare tourists' choice patterns with the prediction of restaurant operators in the tourism provinces of Gangwon-do, Empirical data for this study were collected from the 77 tourists and 66 restaurants operators. The attributes and attribute levels for the hypothetical profiles were decided from a focus group interview and 15 profiles were selected from fractional factorial designs. The SPSS/WIN 12,0 conjoint procedure was used to calculate the utility scores and simulate the profiles, According to the analysis on the relative importance of tourists' choice attributes of restaurants, food taste was the most important attribute(36.9%), followed by facility cleanliness(28.5%), dishes cleanliness(24.5%), price(19.3%) and service(18.3%). The tourists' ratings of the importance of the individual attributes differed from the ranking of the relative importance of the same attributes as derived from the conjoint analysis. The operators rated dishes cleanliness(27.6%) as also important, followed by food taste(27.7%), in choosing a restaurant Tourists' preference and operators' prediction of hypothetical profiles showed significant difference in L(p < .05), O(p < .01), M(p < .05), and H(p < .01) restaurants. Operators who want to differentiate themselves from their competitors should make decisions based on an increased understanding of tourists' restaurant choice decision process and measure the latent needs of tourists in the tourism provinces.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.790-798
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• 2008

Counter-rotating axial flow fan(CRF) consists of two counter-rotating rotors without stator blades. CRF shows the complex flow characteristics of the three-dimensional, viscous, and unsteady flow fields. For the understanding of the entire core flow in CRF, it is necessary to investigate the three-dimensional unsteady flow field between the rotors. This information is also essential to improve the aerodynamic characteristics and to reduce the aerodynamic noise level and vibration characteristics of the CRF. In this paper, experimental study on the three-dimensional unsteady flow of the CRF is performed at the design point(operating point). Flow fields in the CRF are measured at the cross-sectional planes of the upstream and downstream of each rotor using the $45^{\circ}$ inclined hot-wire. The phase-locked averaged hot-wire technique utilizes the inclined hot-wire, which rotates successively with 120 degree increments about its own axis. Three-dimensional unsteady flow characteristics such as tip vortex, secondary flow and tip leakage flow in the CRF are shown in the form of the axial, radial and tangential velocity vector plot and velocity contour. The phase-locked averaged velocity profiles of the CRF are analyzed by means of the stationary unsteady measurement technique. At the mean radius of the front rotor inlet and the outlet, the phase-locked averaged velocity profiles show more the periodical flow characteristics than those of the hub region. At the tip region of the CRF, the axial velocity is decreased due to the boundary layer effect of the fan casing and the tip vortex flow. The radial and the tangential velocity profiles show the most unstable and unsteady flow characteristics compared with other position of rotors. But, the phase-locked averaged velocity profiles of the downstream of the rear rotor show the aperiodic flow pattern due to the mixture of the front rotor wake period and the rear rotor rotational period.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.1
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• pp.241-246
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• 2003

Bambusae Caulis in Liquamen(BCL) has been used to relieve the cough and asthma, and remove the phlegm in traditional Oriental medicine. In recent years, it was studied for its antiinflammatory, antiallergenic, immune-modulating, and anticarcinogenic capabilities. This experiment was performed to evaluate the microarray profiles of CD genes in human mast cells before and after BCL treatment. The results are as follows: The expression of 51 of the genes studied was up-regulated in the Bel-treated group; they include the genes coding L apoferritin, beta-2-microglobulin, ferritin light polypeptide, CD63, monocyte chemotactic and activating fact, heme oxygenase 1, CD140a, integrin alpha M, colony stimulating factor 2 receptor, eukaryotic translation elongation factor, CD37, interleukin 18, NADH dehydrogenase 1 beta, CD48, 5-lipoxygenase activating protein, interleukin 4, ribosomal protein L5, GABA(A) receptor-associated protein, beta-tubulin, integrin beta 1, CD162, CD32, lymphotoxin beta, alpha-tublin, integrin alpha L, CD2, CD151, CD331, 90 kDa heat shock protein, CD59, CD3Z, microsomal glutathione S-transferase 2, CD33, CD162R, cyclophilinA, CD84, interleukin 9 receptor, interleukin 11, CD117, CD39-Like 2, and so forth. The expression of 7 of the genes studied was down-regulated in the BCL-treated group; they include the genes coding con, CD238, SCF, CD160, CD231, CD24, and CD130. Consequently, the treatment of BCL on the human mast cells increased the expression of 51 genes and decreased the expression of 7 genes. These data would provide a fundamental basis to the traditional applications of Bambusae Caulis in Liquamen.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1237-1244
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• 2015

A gerotor can be manufactured in a miniature size because it has a high discharge per cycle and a simple structure. Gerotors are widely used for the lubrication oil of an engine and as the hydraulic source of an automatic transmission. Recently, improvements in fuel efficiency and noise reduction have come to the fore in the automobile industry, and it has been necessary for better fuel efficiency to continuously improve the flow rate and noise of internal gear pumps through the optimal design of the gerotor and port shape. In this study, gerotors were generated based on the equations derived for a lobe shape with multiple profiles (ellipse 1-elliptical involute-ellipse 2). The ranges of the design parameters were considered to prevent a cusp and loop. In addition, the optimal lobe shape was obtained by determining the influence of the lobe shape on the performances (flow rate, irregularity, etc.), according to the values of the design parameters.

• Korean Journal of Plant Resources
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• v.21 no.1
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• pp.41-46
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• 2008

Molecular relationship and genetic diversity of 21 wild tea collections which grown natural region in Korea were investigated based on PCR-RFLP analysis using DFR genes. Approximately 1.4kb fragment of the DFR gene from wild tea samples were successfully amplified use DFR 4+5 primer pair. On the bases of restriction fragment length polymorphism(RFLP) analysis using Hpa II and Mse I enzymes, three different band patterns shown from Hpa II enzyme and showed genetic diversity between same region wild tea group. Six kind of restriction enzyme profiles obtained from digested with restriction endonuclease Mse I and shown two kind of restriction enzyme profiles collected from same region wild tea at Ungpo. The results of RFLP analysis indicated that wild tea showed genetic diversity among different regions of tea groups, but also between same region wild tea.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.269-276
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• 2012

An air core is generated during draining through an axisymmetrically placed circular orifice after rotating a cylindrical tank filled with a liquid. If an air core is generated, the draining flow rate decreases and the draining time increases. In this study, the process of the formation of the air core and internal flow characteristics in a cylindrical tank are studied by numerical methods. Several methods are used in the analysis, and the results are compared with experimental results to obtain the appropriate scheme. Axial, radial, and swirl velocity profiles on a variety of heights are shown graphically, and the internal flow structure is analyzed from the velocity profiles, the vector plot, and the stream function distribution.

• Toxicological Research
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• v.29 no.2
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• pp.137-142
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• 2013

Arsenic (As) is a well-known human carcinogen and its dietary exposure has been found to be the major route of entry into general population. This study was performed to assess the body levels of As and their associated factors in Korean adults by analyzing total As in urine. Urine and blood samples were collected from 580 adults aged 20 years and older, who had not been exposed to As occupationally. Demographic information was collected with the help of a standard questionnaire, including age, smoking, alcohol intake, job profiles, and diet consumed in the last 24 hrs of the study. Total As, sum of As(III), As(V), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), in urine was determined using atomic absorption spectrometer involving hydride generation method. The geometric mean concentration of total As in urine was $7.10{\mu}g/L$. Urine As was significantly higher in men ($7.63{\mu}g/L$) than in women ($6.75{\mu}g/L$). Age, smoking, alcohol consumption, and job profiles of study subjects did not significantly affect the concentration of As in urine. No significant relationship was observed between body mass index (BMI), Fe, and total cholesterol in serum and urinary As. Urine As level was positively correlated with seaweeds, fishes & shellfishes, and grain intake. A negative correlation between urinary As level and HDL-cholesterol in serum and meat intake was observed. Overall, these results suggest that urinary As concentration could be affected by seafood consumption. Therefore, people who frequently consume seafood and grain need to be monitored for chronic dietary As exposure.

• Nutritional Sciences
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• v.8 no.4
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• pp.250-255
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• 2005

The purpose of this study was to investigate the relationship among plasma leptin, lipid profiles, insulin levels, and percentage of body fat of 72 schoolchildren from Obese Clinic Center in Seoul. The subjects divided into two groups: 39 obesity children [obesity index greater than $20\%$] who did not have a discernable medical cause of their obesity and 33 children with a obesity index less than $20\%$. The mean age, height, and obesity index of the subjects were 10.4 years, 144.0 cm, and $21.3\%$, respectively. The mean glucose and insulin levels of the obese children were 80.5 mg/dl and $13.3\;{\mu}IU/mL$ and those of the non obese children were 82.0 mg/dl and $4.2\;{\mu}IU/mL$, respectively. Obese children had significantly (p<0.05) higher level of total cholesterol, triglyceride, VLDL-cholesterol, LDL-cholesterol, and insulin concentration than non-obese children. However obese children had a lower level of HDL-cholesterol than non-obese children. Plasma leptin level were also positively correlated with BMI (p<0.000l), body fat (p<0.0001), tricep skinfold thickness (p<0.0001), mid arm circumference (p<0.0001), and waist hip ratio (p<0.0001). Plasma leptin showed a significantly positive correlation with insulin (p<0.0001), total cholesterol (p<0.0001), LDL-cholesterol (p<0.0001), and triglyceride (p<0.0001) levels, however, it was negatively correlated with HDL-cholesterol (p<0.0001) levels. In conclusion, the concentration of leptin in the blood is significantly correlated with the amount of body fat, BMI, plasma insulin, and plasma lipid profiles.