• Proceedings of the Materials Research Society of Korea Conference
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• 2008.05a
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• pp.37.1-37.1
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• 2008

• The Korean Journal of Ecology
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• v.6 no.2
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• pp.81-89
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• 1983

The change of environmental factors with flow rates were studied quantitatively for two rivers, the Nakdong River and the Sin stream, which have different basins in ecosystem structures, during short period after a heavy rain. In the Nakdong River, transparency, DO, alkalinity and hardness were negatively correlated with the flow rate by logarithmic function, but the concentration of SiO2 was relatively constant regardless of the flow chage. In the Sin stream, transparency, alkalinity, hardness and the concentration of NH3-N, NO2-N and SO4= showed negative correlation with the flow rate by logarithmic function. The ratios of maximum to minimum values for aquatic environmental factors during the samller than that for flow rate in the respective rivers (28 in the Nakdong R.; 50 in the Sin S.). Immediately after the heavy rain, the concentrations of NO2-N, NH3-N and PO4-P in the Sin stream were 8, 6 and 1 times as high as those in the Nakdong River, respectively, but in the stable flow state, those became 94, 25 and more than 10 times, respectively. The load for most of the dissolved environmental constituents changed similarly to the flow rate in both rivers. It is notable that, at the stable flow state, the loads for NH3-N (59g/sec) and NO2-N (3.3g/sec) in the Sin stream were 4.3 and 1.3 times as high as those in the Nakdong River.

• Food Science of Animal Resources
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• v.41 no.1
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• pp.59-70
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• 2021

A method for simultaneous detection of fipronil (F) and its metabolites fipronil desulfinyl (FD), fipronil sulfide (FS), fipronil sulfone (FSO) in chicken eggs was applied and validated. It includes single-step, cheap, effective, rugged, safe-based method (SinChERS) for sample preparation and ultra high performance liquid chromatography coupled with mass spectrometry (UHPLC-MS/MS) for chemical analysis. Results suggested that formic acid enhanced the recovery of 4 target residues and 1% supplementation to acetonitrile gained higher recoveries than that of 5%. SinChERS integrated extraction and clean-up steps into one, with shorter time (1.5 h) to operate and higher recoveries (97%-100%) than HLB, Envi-Carb-NH2 and quik-easy-cheap-effective-rugged-safe method (QuEChERS), and it consumed the smallest volume of extracting solvent (10 mL) as QuEChERS. Quantitative analyses using external standard method suggested the linear ranges of 4 target compounds were 1-20 ㎍/L with R2 >0.9947. The limit of detection (S/N>3) and quantification (S/N>10) were 0.3 ㎍/kg and 1 ㎍/kg. Recoveries ranged from 89.0% to 104.4%, and the relative standard deviations (n=6) at 1, 10, and 20 ㎍/kg were lower than 6.03%. Thirty batches of domestic eggs (500 g each) were detected by the established SinChERS-based UHPLC-MS/MS and no target residues were detected in all samples. The method developed in this study is a rapid, sensitive, accurate and economic way for multi-residue analysis of fipronil and its metabolites in eggs.

• The Journal of Korean Medicine
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• v.21 no.4
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• pp.183-192
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• 2000

Objectives : The present study was carried out to investigate the effects of Danchun-hwan(DCH) on the peroxynitrite-induced neural cell death in human neuroblastoma cell line, SH-SY5Y. Methods : The cultured cells were pretreated with DCH and exposed to 3-morpholinosydnonimine(SIN-1) that simultaneously generates NO and superoxide, thus possibly forming peroxynitrite. The cell damage was assessed by using MTT assay and crystal violet staining. Results : Exposure of the cells to SIN-1 for 24hr induced 75% apoptotic cell death, as evaluated by the occurrence of morphological nuclear changes characteristic of apoptosis using 4', 6-diamidino-2-phenylinole(DAPI). However, pretreatment of SH-SY5Y with the water extracts of DCH, inhibited the apoptotic cell death in a dose-dependent manner. DCH also inhibited SIN-1-induced apoptotic caspase 3-like protease activity in a dose-dependent manner. DCH recovered the depleted glutathione levels by SIN-1. Conclusions : Taken together, it is suggested that DCH protected human neuroblastoma cell line, SH-SY5Y, from the free radical injury mediated by peroxynitrite by a mechanism of elevating antioxidant, GSH.

• 한국해양학회지
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• v.5 no.1
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• pp.6-13
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• 1970

Ten days and monthly mean temperatures were analysed daily data observed during July, 1916 to March, 1970 statistically. Periodic characters were calculated by Δn, new method of approximate solution of Schuster Method. According to ten days mean temperatures, annual variation function is F($\theta_d$)=16.29-5.27 cos $\theta_d$+0.75 cos2 $\theta_d$-3.14 sin $\theta_d$+1.16 sin2 $\theta_d$-0.63 sin $\3{theta}_d$, where $\theta_d$=$-\frac{\pi}{18}$(d-3), d is the order of ten days period, 1 to 36. Annual mean water temperature is 16.3$^{\circ}C$, minimum in the last ten days of February 10.9$^{\circ}C$, maximum in the last ten days of August 24.5$^{\circ}C$. Periodic character of secular variation shows 11 year and its curve is F($\theta_y$)=16.29+0.53 cos $\theta_y$ -0.16cos $2{\theta}_y$+0.10 cos$3{\theta}_y$-0.10 sin $\theta_y$, where $\theta_y$=2$-\frac{2\pi}{11}$(y-1920), y is calendar year. And the relation between air temperature x and water temprature y is following. y=9.67 1.035$\^x$

• The Journal of Korean Obstetrics and Gynecology
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• v.23 no.2
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• pp.145-153
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• 2010

Purpose: Sjogren's syndrome is a type of autoimmune disease and characterized by the keratoconjunctivitis sicca, xerostomia, dryness of mouth & eyes and rheumatoid arthritis or another connective tissue disease. In the Traditional Korean Medicine, there is few report to diagnose and treat Sjogren's syndrome. Methods: The subject was a typical Sjogren's syndrome in 48-year old women whose complaints were dryness of mouth and eyes, severe general myalgia. The author treated her with acupuncture and herbal medicine therapy, then evaluated with MMQ score, XQS grade and VAS score on a regular basis. Results: After treatment, clinical symptoms were improved, MMQ score and XQS grade were decreased. Conclusion: The Traditional Korean Medical Therapy combined acupuncture with herbal medicine relieves the symptom of Sjogren's syndrome.

• Journal of the Korean Ceramic Society
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• v.26 no.1
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• pp.116-122
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• 1989

MOR test and concentric ring test were performed to evaluate the failure probability of sin/hip Si3N4 under uniaxial and biaxial stress state, respectively. Their failure probabilities were analized with KARA program based on Weibull PIA model and Batdorf model with 5 criteria, and they were compared with experiments. PIA model is in best accordance with experiments in higher fracture strength regions, especially for Pf 0.3. But in lower fracture strength region, none of the models predicts the failure probabilities appropriately.

• Magazine of the Korean Society of Agricultural Engineers
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• v.6 no.1
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• pp.737-749
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• 1964

This is an attempt to find out the periodicity of the natural hydrological phenomena by the function of vibration periodicity, under the assumption that the phenomena are periodic. The result of this study at Suwon is as foIlows: 1. Annual precipitation and tota1 precipitation during summer season have the periodicity of five years. 2. Annual temperature and tota1 temperature during winter season have the periodicity of seven years. 3. The regulation curve equations of the above vibration phenomena are as foIlows: a Annual precipitation. Y = 1149-250cos2/5${\PI}$t-33 sin 2/5 t b. Total precipitation during summer season. Y=212'.9+33.06sin (2/5${\PI}$t+$88^{\circ}$13') c. Annual temperature. Y= 140.3+3.3 sin (2/7${\PI}$t+ $154^{\circ}C$55')

• Kyungpook Mathematical Journal
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• v.46 no.1
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• pp.111-118
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• 2006

The present paper investigates the weighted $L^1$-convergence of Gr$\ddot{u}$nwald interpolatory operators based on the zeros of the second Chebyshev polynomials $U_n(x)=\frac{sin(n+1)\theta}{sin\theta}$. The approximation rate is sharp.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.6
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• pp.150-157
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• 2002

In textured material, diffraction angle $2{\theta}$ usually shows a nonlinear relation against $sin^2{\psi}$ due to elastic anisotropy of crystals. SPHD and SPCD steel is cold-rolled carbon steel for automobile. The characteristics X-ray for stress measurement is Cr $K_{\alpha}\;and\;Mo\;K_{\alpha}$ characteristic X-ray. The $2{\theta}-sin^2{\psi}$ diagram under elastic strain seems to have a linear behavior using regression line of data but has a nonlinear behavior in distribution of data by Cr $K_{\alpha}$ characteristic X-ray. As the plastic strain of specimen increases, the nonlinearity of $2{\theta}$ with respect to $sin^2{\psi}$ increases remarkably. On the other hand, the diffraction angle $2{\theta}$ by Mo $K_{\alpha}$ characteristic X-ray shows a good linearity on $2{\theta}-sin^2{\psi}$ diagram under plastic strain as well as elastic strain. Therefore, this paper presents the measurement of residual stress in cold-rolled carbon steel for automobile using penetration depth of Mo $K_{\alpha1}$ characteristic X-ray and multiplicity factor of crystal diffraction plane.