• Journal of Korea Multimedia Society
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• v.11 no.8
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• pp.1072-1081
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• 2008

We can categorize the network address allocation mechanism into two types. One is to assign a unique network address using the address allocation server and the other is to make a random address by itself and process the DAD(Duplicate Address Detection) procedure. In this paper we suggest a new address allocation mechanism based on the signal strength for the PLC-based home network. As the combined mechanism of two types this mechanism allocates a unique address for the new node from one of the existing nodes with the simple equation and with the priority based on the signal strength from the new node to the existing nodes. We can use this mechanism for the self-healing function when the packet from the source node may not be delivered to the destination node directly. We developed the simulator for our mechanism using the C# programming and verified the network address assigned uniquely based on the signal strength.

• The Journal of the Acoustical Society of Korea
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• v.11 no.4
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• pp.5-13
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• 1992

The vibration of a vehicle, which is caused by and transmitted from the engine, has significant effect on the ride comfort and the dynamic characteristics of the engine mount system has direct influence on the vibration and noise of the vehicle. This paper examines the body shake caused by the engine excitation force on engine key-off of a jeep by experiment and computer simulation using a general purpose mechanical system program, DADS. The computer simulation model consists of the engine, body including frame, and front and rear axles and each axle has right and left tires. The force element between body and suspension is modeled as a combination of suspension spring and damper, and the unsprung mass has roll and pitch motion. The body shake obtained from experiment was compared with the result of computer simulation. Parametric study of the body shake on engine key-off is performed with changing the stiffness of engine mount rubber, the engine mount installation angle and position of engine mounts by using the verified computer simulation model.

• ALGAE
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• v.35 no.2
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• pp.177-187
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• 2020

Cyanobacteria have been widely reported to produce a variety of UV-absorbing mycosporine-like amino acids (MAAs). Herein, we reported production of the unusual MAA, mycosporine-glycine-alanine (MGA) in the cyanobacterium Sphaerospermopsis torques-reginae ITEP-024 using a newly developed UHPLC-DAD-MS/HRMS (ultra-high performance liquid chromatography-diode array detection-high resolution tandem mass spectrometry) method. MGA had previously been first identified in a red-algae, but S. torques-reginae strain ITEP-024 is the first cyanobacteria to be reported as an MGA producer. Herein, the chemical structure of MGA is fully elucidated from one-dimensional / two-dimensional nuclear magnetic resonance and HRMS data analyses. MAAs are unusually produced constitutively in S. torques-reginae ITEP-024, and this production was further enhanced following UV-irradiance. It has been proposed that MAA biosynthesis proceeds in cyanobacteria from the pentose phosphate pathway intermediate sedoheptulose 7-phosphate. Annotation of a gene cluster encoded in the genome sequence of S. torques-reginae ITEP-024 supports these gene products could catalyse the biosynthesis of MAAs. However, addition of glyphosate to cultures of S. torques-reginae ITEP-024 abolished constitutive and ultra-violet radiation induced production of MGA, shinorine and porphyra-334. This finding supports involvement of the shikimic acid pathway in the biosynthesis of MAAs by this species.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.148-156
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• 2000

For the in-line three cylinder engine whose crankshaft has a phase of 120 degrees, the total sum of unbalanced inertia forces occurring in each cylinder will be counterbalanced among three cylinders. However, parts of inertia forces generated at the No.1 and No.3 cylinders will cause a primary moment about the No.2 cylinder. In order to eliminate this out-of-balance moment, a single balance shaft has been attached to the cylinder block so that the engine durability and riding comfort may be further improved. Accordingly, the forced vibration analysis of the in-line three cylinder engine must be implemented to meet the required targets at an early design stage. In this paper, a method to reduce noise and vibration in the 800cc, in-line three cylinder LPG engine is suggested using the multibody dynamic simulation. The static and dynamic balances of the in-line three cylinder engine are investigated analytically. The multibody dynamic model of the in-line three cylinder engine is developed where the inertia properties of connecting rod, crankshaft, and balance shaft are extracted from their FE-models. The combustion pressure within the No.1 cylinder in three significant operating conditions(1500rpm-full load, 4000rpm-full load and 7000rpm-no load)is measured from the actual tests to excite the engine. The vibration velocities at three engine mounts with and without balance shaft are evaluated through the forced vibration analysis. Obviously, it is shown that the vibration of the in-line three cylinder engine with balance shaft is reduced to the acceptable level .

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.3
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• pp.244-249
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• 2011

A sensitive and rapid high-performance liquid chromatographic-tandem mass spectrometric (HPLC/MS/MS) assay was developed for the determination of soyasaponins in soybean. Among soyasaponins, soyasaponin I was isolated and characterized from methanol extracts of soybean as analytical standards and the development of a new analytical procedure for quantification of its content in various cultivars. The structures of these compound was elucidated by $^1H$, $^{13}C$ NMR experiments and by mass spectrometric analysis. Aqueous ethanol extracts of soybean samples were injected on an Agilent XDB-C18 column ($4.6mm{\times}50mm$, $1.8{\mu}m$) with a mobile phase consisting of 10 mM ammonium acetate-acetonitrile, a flow rate of 0.3 mL/min and a total run time of 8 min. Detection was performed by mass spectrometer bin the multiple reaction monitoring (MRM) mode with negative electrospray ionization (ESI) m/z at 941 ${\rightarrow}$ 615 for soyasaponin I. In the 9 soybean samples, contents of soyasaponin I ranged from 205 to 726 mg/kg, and correlated negatively with seed size.

• Analytical Science and Technology
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• v.8 no.3
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• pp.229-236
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• 1995

Multiple-step gradient method was used for the analysis of free amino acids in physiological fluids by high-performance liquid chromatography with diode array detector on the Amino Quant $C_{18}$ column under the condition of pH 7.2 of buffer solutions. Plasma samples of normal Korean people and abnormal Korean people who have schizophrenia were subjected to derivatization with o-phthalaldehyde in the presence of 3-mercaptopropionic acid. Quantitative analysis of amino acids in physiological fluids by internal standard method gave highly reproducible results within a relative standard deviation of less than 2~6%. And amino acids amounts of physiological fluids of Korean people gave some different results from those of foreigners. There was large differences in tyrosine amount between normal and abnormal man.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.111-117
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• 2011

BACKGROUND: Anthocyanins have been recognized as health-enhancing substances due to their antioxidant activity, anti-inflammatory, anticancer, and hypoglycemic effects. The objective was to identify anthocyanins-rich rice grains for the development of functional foods and/or functional food colorants METHODS AND RESULTS: Rice grains of one black and three red-hulled rice varieties were extracted with acidified 80% aqueous methanol. The antioxidant activity of the methanolic extracts was screened on TLC plates and in an in vitro assay using DPPH (1, 1-diphenyl-2-picrylhydrazyl) as a free radical source. Red-hulled rice varieties exhibited higher antioxidant activity (88%, 1 mg/mL) than black rice (67%, 1 mg/mL). Among the red-hulled varieties tested, rice variety SSALBYEO54 (901452) was the most active (72%, 0.5 mg/mL). Rice extracted anthocyanin compounds were analyzed by HPLC-DAD-FLD and LC-MS/MS. Red-hulled varieties comprised cyanidin-3-glucoside in addition to ferulic acid esters, apigenin and kaempferol glycosides. CONCLUSION(s): Anthocyanins identified in the black rice variety were cyanidin-7-O-galactoside, cyanidin-3-Oglucoside, cyanidin-3'-O-glucoside, cyanidin-5-O-glucoside, cyanidin-3, 7-O-diglucoside, cyanidin-3, 5-O-diglucoside and peonidin-4'-O-glucoside. The results of this study show that the black rice (IT212512) and red-hulled rice variety SSALBYEO54 (901452) contain notable antioxidant activity for potential use in nutraceutical or functional food formulations.

• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.122-129
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• 2020

BACKGROUND: Dissipation patterns of insecticides (acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam) on strawberry grown in plastic-covered greenhouse were evaluated at 7 intervals including the preharvest interval after application. This study was performed to determine the residue concentrations, half-lives and dissipation rates in strawberry for the harvest periods. METHODS AND RESULTS: Acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam were applied in accordance with critical good agricultural practices for strawberry. Strawberry samples were collected at 0, 1, 2, 3, 5, 7 and 10 days after application. Quantitaion was performed by HPLC/DAD and HPLC-MSMS system with C₁₈ column. The limit of quantitation (LOQ) values varied between were 0.00025~0.05 mg/kg on strawberry. The recoveries of acequinocyl, clothianidin, diflubenzuron, thiacloprid and thiamethoxam at two concentrations ranged from 70.9~104.9% on strawberry. The half-lives of pesticide dissipation on strawberry for two fields ranged from 1.3~8.2 days. The dissipation rates were evaluated according to the statistics method with a 95% confidence. CONCLUSION: The residue levels of insecticides (acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam) on strawberry at 0-day after application were below the specified values by Korean MRL. To estimate dissipation rate constant of pesticides on crop for harvest periods, it is important to set the pre-harvest residue limit for human health and consumer protection in Korea.

• YAKHAK HOEJI
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• v.55 no.2
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• pp.121-126
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• 2011

Sipjundaebo-tang was a well-known restorative traditional herbal prescription that used to treat anemia, anorexia, fatigue and inflammation. In this study, we examined the bioconversion of compounds in the Sipjundaebo-tang (SJ) and fermented Sipjundaebo-tang with Lactobacillus fermentum KFRI 164 (FSJ) using established HPLC-DAD method. The chromatogram of FSJ has shown that the contents of six bioactive compounds 5-HMF, paeoniflorin, ferulic acid, cinnam aldehyde, decursin, glycyrrhizin in SJ has decreased. And the contents of unknown compounds (1), (2), (3), (4) and (5) in FSJ were higher than each contents of SJ. The antioxidant activities of SJ and FSJ were conducted by DPPH free radical and Hydrogen peroxide ($H_2O_2$) scavenging assay. Electron donating activity (EDA, %) value of FSJ has shown higher than 21.9% and 14.5% at a concentration of 0.5 mg/ml for DPPH radical scavenging activity and $H_2O_2$ scavenging activity, respectively. Also, the neuroprotective activities of SJ and FSJ against glutamate-induced oxidative stress in a mouse hippocampal cell line (HT22) were evaluated by MTT assay. As a result, FSJ has shown higher neuroprotective activity than 56.5% comparing with SJ. In conclusion, the fermented SJ using microorganism could convert compounds in SJ and enhance antioxidant activity and neuroprotective activity.

• Journal of Life Science
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• v.17 no.1 s.81
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• pp.150-161
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• 2007

Acori graminei Rhizomn (AGR) is a perennial herb which has been used clinically as a traditional oriental medicine against stroke, Alzheimer's disease, and vascular dementia. We investigated the effect of AGR on the modulation of gene expression profile in a hypoxic model of cultured rat cortical cells. Rat cerebrocortical cells were grown in Neurobasal medium. On DIV12, cells were treated with AGR $(10ug/m\ell)$, given a hypoxic shock (2% $O_2$, 3 hr) on DIV14, and total RNAs were prepared one day after shock. Microarray analyses indicated that the expression levels of most genes were altered within the global M values +0.5 and -0.5, i.e., 40% increase or decrease. There were 750 genes which were upregulated by < global M +0,2, while 700 genes were downregulated by > global M -0.2. The overall profile of gene expression suggests that AGR suppresses apoptosis (upregulation of anti-apopotic genes such as TEGT, TIEG, Dad, p53, and downregulation of pro-apopotic genes such as DAPK, caspase 2, pdcd8), ROS (upregulation of RARa, AhR), and that AGR has neurotrophic effects (upregulation of Aktl, Akt2). These results provide a platform for investigation of the molecular mechanism of the effect of AGR in neuroprotection.