• Journal of Sensor Science and Technology
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• v.5 no.5
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• pp.21-29
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• 1996

A piezoresistive silicon acceleration sensor with 8 beams, utilized by an unique silicon micromachining technique using porous silicon etching method which was fabricated on the selectively diffused (111)-oriented $n/n^{+}/n$ silicon subtrates. The width, length, and thickness of the beam was $100\;{\mu}m$, $500\;{\mu}m$, and $7\;{\mu}m$, respectively, and the diameter of the mass paddle (the region suspended by the eight beams) was 1.4 mm. The seismic mass on the mass paddle was formed about 2 mg so as to measure accelerations of the range of 50g for automotive applications. For the formation of the mass, the solder mass was loaded on the mass paddle by dispensing Pb/Sn/Ag solder paste. After the solder paste is deposited, Heat treatment was carried out on the 3-zone reflow equipment. The decay time of the output signal to impulse excitation of the fabricated sensor was observed for approximately 30 ms. The sensitivity measured through summing circuit was 2.9 mV/g and the nonlinearity of the sensor was less than 2% of the full scale output. The output deviation of each bridge was ${\pm}4%$. The cross-axis sensitivity was within 4% and the resonant frequency was found to be 2.15 KHz from the FEM simulation results.

• Analytical Science and Technology
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• v.26 no.2
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• pp.142-153
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• 2013

A new, rapid, and simple analytical method was developed and validated using high performance liquid chromatograph-photodiode array detector (HPLC-PAD) for the determination of lepimectin residues in agricultural commodities. The lepimectin residues in samples were extracted with methanol, partitioned with dichloromethane, and then purified with glass column filled with subsequently to aminopropyl ($NH_2$) solid phase extraction (SPE) cartridge. The purified samples were detected using HPLC-PAD. Correlation coefficient ($R^2$) of both lepimectin $A_3$ and $A_4$ solutions were 0.9999. The method was validated using cucumber spiked with lepimectin at 0.02 and 0.2 mg/kg and pepper, mandarin, hulled rice, potato, soybean at 0.02 and 0.5 mg/kg. Average recoveries were 76.0~114.8% with relative standard deviation less than 10%, and limit of detection (LOD) and limit of quantification (LOQ) were 0.005 and 0.01 mg/kg, respectively. The result of recoveries and overall coefficient of variation of a laboratory results in Gwangju regional KFDA and Daejeon regional KFDA was followed with Codex guideline (CAC/GL 40). Therefore, developed method in this study is accurate, rapid, and appropriate for lepimectin determination and will be used to keep safety of lepimectin residues in agricultural products.

• Journal of Korean Society on Water Environment
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• v.21 no.3
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• pp.248-255
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• 2005

Since the water quality of drinking water sources has been recognized as a big issue, the ministry of Environment in Korea is designing the total maximum daily load (TMDL) program for 4 major large rivers. The TMDL program can be successfully performed as controling the nonpoint pollutants from watershed area near the river. Of the various landuses in nonpoint pollution, parking lots and bridges are stormwater intensive landuses because of high imperviousness and high pollutant mass emissions from vehicular activities. Vehicle emissions from those areas include different pollutants such as heavy metals, oil and grease and particulates from sources such as fuels, brake pad and tire wear, etc. Especially the pollutant washed-off from the landuses are directly affecting to the river water quality. Therefore this research was conducted to understand the magnitude and nature of the stormwater emissions with the goal of quantifying stormwater pollutant concentrations and mass emission rates of pollutants from parking lot and bridges in Korea. In Kongju city areas, two monitoring sites were equipped with an automatic rainfall gages and an automatic flow meter for accumulating the useful data such as rainfall, water quality and runoff flow. This manuscripts will show the concentration changes during storm duration and EMCs to characterize the concentration profiles in different land uses. Also the first flush criteria will be suggested using dynamic EMCs. The definition of dynamic EMC is a new approach explaining the relationship of EMC and first flush effect.

• Journal of the Korean Society of Radiology
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• v.85 no.1
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• pp.247-251
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• 2024

Respiratory epithelial adenomatoid hamartoma (REAH) in the head and neck is a rare benign lesion containing glandular tissue covered with ciliated respiratory epithelium. In the head and neck, REAH of the nasal cavity, paranasal sinuses, and nasopharynx have been reported in literature. Due to rareness of REAH and insufficient knowledge of its imaging features, the diagnosis can be challenging when we encounter a non-specific cystic mass at an uncommon site in the head or neck. Here, we report the case of a pathologically confirmed REAH showing a cystic mass centered at the buccal space (retromaxillary fat pad) with CT and MRI findings.

• Nutrition Research and Practice
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• v.1 no.4
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• pp.291-297
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• 2007

This study was conducted to investigate the effect of dietary soluble fiber administration and/or high fat diet on serum and brain neurohormonal profiles, adipose tissue mass and body weight gain in Sprague-Dawley rats. Four groups of rats were respectively fed 10% fat diet (C), 10% fat plus pectin diet (P), 20% fat diet (HFC) and 20% fat plus pectin diet (HFP) for 4 weeks. In HFP group, the food and energy intake, body weight gain, FER including fecal excretion were the smallest (p<0.05). Serum HDL-cholesterol, triglyceride and glucose level were also the lowest in HFP group (p<0.05). The weight of brain, epididymal fat pad and adrenal gland except liver didn't show any significant differences among groups. Interestingly serum norepinephrine concentration of HFP group tended to be higher, but dopamine concentration tended to be lower than those of HFC group. However serum catecholamine concentration didn't show any significant differences among all groups. Norepinephrine and epinephrine contents of right portion of midbrain of P and HFP groups were remarkably lower than those of the C group. These results suggested that soluble fiber pectin consumption might affect neurohormonal profiles in serum and brain according to dietary fat level.

• Journal of Nutrition and Health
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• v.36 no.5
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• pp.446-451
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• 2003

The purpose of this study was to investigate the effects of wax gourd on weight, triglyceride, leptin and fat cell size in rats fed a high-fat diet. Male Sprague Dawley rats were fed an experimental diet containing total dietary fat at 40% of calories with wax gourd 0%, 5%, 10% and 15% (w/w) for 4 weeks. Weight gain and triglyceride level fell significantly in the 15% wax gourd group compared to the control group. Epididymal fat pad, abdominal fat and perirenal fat tended to decrease in the 15% wax gourd group. Leptin and free fatty acid level were not significantly different among the groups. Fat cell size significantly decreased in the 10% and 15% wax gourd groups compared to the control group. Weight gain correlated positively with visceral fat masses and the levels of leptin and triglyceride. Fat cell size significantly correlated with visceral fat and leptin level. Therefore, the 15% wax gourd diet substantially reduced weight, triglyceride and fat cell size. (Korean J Nutrition 36(5): 446∼451, 2003)

• Journal of the Korean Society for Precision Engineering
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• v.19 no.9
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• pp.166-171
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• 2002

The objective of this paper is to investigate the effect of clearance and the configuration of die system on burr formation by FEM analysis and experimental tests. Compared with casting, forging and machining, shearing has been known, especially in heavy or mass-production industries, as a very economical and fast way to obtain the desired shape Recently, the shearing process becomes widely used in the small and light electronic component manufacturing industries. When shearing a part of sheet metal, the burr formed on the cutting edge is usually unavoidable. The burr would not only degrade the precision of products but also causes additional cost for the deburring process. In this paper, the influence of shearing parameters such as clearance and configurations of the lower pad (ejector) on burr formation is investigated by using the experimental and numerical approach. From the experimental results, it has been shown that the more narrow clearance gives the smaller burr height and the higher shearing forces. The removal of lower holder also makes the sheared surface integrity and the dimensional accuracy become worse. The FEM results (using DEFORM-2D) show good agreement with the experimental results.

• Korea-Australia Rheology Journal
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• v.18 no.4
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• pp.199-207
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• 2006

Measurements by Luap et al. (2005) of elongational viscosity and birefringence of two nearly monodisperse polystyrene melts with molar masses $M_{w}$ of $206,000g{\cdot}mol^{-1}$ (PS206k) and $465,000g{\cdot}mol^{-1}$ (PS465k) respectively are reconsidered. At higher elongational stresses, the samples showed clearly deviations from the stress optical rule (SOR). The elongational viscosity data of both melts can be modeled quantitatively by the MSF model of Wagner et al. (2005), which is based on the assumption of a strain-dependent tube diameter and the interchain pressure term of Marrucci and Ianniruberto (2004). The only nonlinear parameter of the model, the tube diameter relaxation time, scales with $M_{w}^{2}$. In order to get agreement with the birefringence data, finite chain extensibility effects are taken into account by use of the $Pad\'{e}$ approximation of the inverse Langevin function, and the interchain pressure term is modified accordingly. Due to a selfregulating limitation of chain stretch by the FENE interchain pressure term, the transient elongational viscosity shows a small dependence on finite extensibility only, while the predicted steady-state elongational viscosity is not affected by non-Gaussian effects in agreement with experimental evidence. However, deviations from the SOR are described quantitatively by the MSF model by taking into account finite chain extensibility, and within the experimental window investigated, deviations from the SOR are predicted to be strain rate, temperature, and molar mass independent for the two nearly monodisperse polystyrene melts in good agreement with experimental data.

• Journal of the Korean Society of Clothing and Textiles
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• v.48 no.3
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• pp.543-562
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• 2024

This study used persimmon juice, shuliang, and mud to develop the color of hanji fabrics. Persimmon juice and shuliang were used to perform single and mixing dyeing with heat treatment using the pad-dry-cure (PDC) method. Next, mud dyeing was performed, and the hanji fabrics dyed with persimmon juice and shuliang were developed into Yellow Red (YR) Munsell colors with very low values and chroma. Through scanning electron microscopy, the persimmon juice and shuliang were observed to be evenly treated on the hanji fabrics using the PDC method. Furthermore, the presence of iron ions in the dyed fabrics was confirmed using inductively coupled plasma-mass spectrometry analysis. The stiffness of the fabrics dyed with persimmon juice was the greatest, while it gradually decreased for the fabrics treated with mixing and mud dyeing. With mixing dyeing, the colorfastness to washing improved to grade 4, whereas with mud dyeing, the colorfastness to alkaline sweat greatly improved to grade 4~4-5. Based on these findings, this study confirmed that it is possible to develop hanji fabrics with differentiated textures and colors while ensuring practical colorfastness through mixing and mud dyeing.

• Nutrition Research and Practice
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• v.8 no.6
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• pp.618-624
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• 2014

BACKGROUND/OBJECTIVES: Isoflavones are widely believed to be beneficial to human health, in relation to their antioxidant potentials. Exercise can cause an imbalance between reactive oxygen species (ROS) and antioxidants. This study was conducted in order to investigate the ability of isoflavones in amelioration of oxidative stress induced by exercise. MATERIALS/METHODS: Male Sprague-Dawley rats were assigned to one of four groups: isoflavone-free with no exercise (CON-sd), isoflavone-free with exercise (CON-ex), isoflavone-supplemented with no exercise (ISF-sd), and isoflavone-supplemented with exercise (ISF-ex). Animals exercised on the treadmill for 30 minutes per day, five days per week. TBARS as a marker of oxidative stress and antioxidant enzyme activity, including SOD, GSH-px, and catalase were determined in liver tissue. Serum lipid profile was also examined. RESULTS: A significant effect of isoflavone alone was observed on abdominal fat pad mass. ISF-ex had significantly less abdominal fat pad than CON-ex. Both exercise and isoflavone treatment had significant effects on lowering plasma triglyceride (TG), thus, the ISF-ex group had a significantly lower TG level than the CON-sd group, by 30.9%. However, no differences were observed in plasma cholesterol, HDL-C, and cholesterol/HDL-C ratio. Exercise, isoflavone, and exercise-isoflavone interaction effects were significant on thiobarbituric acid reactive substances (TBARS) (P = 0.001, 0.002, and 0.005, respectively). The CON-ex group showed a higher TBARS level than the other three groups. By contrast, in the ISF-ex group, TBARS was restored to the level of the ISF-sd or CON-sd group. Isoflavone had a significant effect on superoxide dismutase (SOD) (P = 0.022) and catalase activities (P = 0.049). Significantly higher SOD and catalase activities were observed in ISF-ex than CON-ex. SOD and catalase activities showed an inverse pattern of TBARS. Taken together, isoflavones increased the activities of SOD and catalase with concomitant decreases in TBARS, indicative of decreased oxidative stress. CONCLUSIONS: Isoflavone supplementation enhances antioxidant action with attenuation of exercise-induced oxidative stress, as measured by decreases in TBARS, and inhibits body fat accumulation and plasma TG increase. Antioxidative effects ascribed to isoflavones may be partially exerted via enhancement of antioxidant enzyme activities.