• Journal of the Korean Chemical Society
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• v.13 no.1
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• pp.49-55
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• 1969

X-ray Fluorescence Spectrographic method has been applied for the rapid determination of main components, such as $SiO_2$, $Al_2O_3$, $Fe_2O_3$, CaO, MgO and $K_2O$ in Silicate Minerals. In this method, Boric Acid was used as a binder after fusion with Lithium Tetraborate in the briquet-making process. The Lithium Flubride, Ammonium di-Hydrogen Phosphate and Ethylene Diamine d-Tartrate crystals were used with Scintillation counter and Gas Flow counter as the detectors. Several influences on this method were discussed, including the particle size of samples and reducing of the matrix effects by dilution with Boric Acid and addition of Lanthanum Oxide with the diluent. In order to test the reproducibility of this method described above, the determination of the same kind of samples were carried out repeatedly, and the results obtained were presented in the table. Calibration curves for each element were presented, and the application of the method was tested with International Rock Standard T-Ⅰ. All the results obtained by X-Ray Fluorescence Spectrographic method were compared with the results by conventional chemical method.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.596-601
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• 2010

Background: This study was designed to evaluate the efficacy of a mixture of hyaluronic acid and sodium carboxymethyl cellulose ($Guardix-sol^{(R)}$) on experimental pericardial adhesion. Material and Method: Thirty rats were divided into 2 groups of 15 rats each and pericardial mesothelial injury was induced during surgery by abrasion. In the control group, blood and normal saline were administered into pericardium; in the test group, blood and HA-CMC solution were administered. Pericardial adhesions were evaluated at 2 weeks (n=5), 4 weeks (n=5), and 6 weeks (n=5) after surgery. The severity of adhesions was graded by macroscopic examination, and the adhesion tissue thickness was analyzed microscopically with Masson trichrome stain and an image processing program. Result: The test group had significantly lower macroscopic adhesion scores ($2.9{\pm}0.6$ : $3.9{\pm}0.4$, p<0.000) compared with the control group. For microscopic adhesion tissue thickness, the test group had lower scores compared with the control group, but this difference was not statistically significant ($91.73{\pm}49.91$ : $117.67{\pm}46.4$, p=0.106). Conclusion: We conclude that an HA-CMC solution ($Guardix-sol^{(R)}$) reduces the formation of pericardial adhesions in this animal model.

• Journal of agricultural medicine and community health
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• v.47 no.2
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• pp.67-77
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• 2022

Objective: This study was to evaluate the effectiveness of an individually tailored program based on self-measurement of blood glucose on health behavior and HbA1c in diabetes and pre-diabetes patients. Methods: The program consisted of seven sessions for 12 weeks which were carried out every two weeks. Almost all sessions were progressed on untact method except for the first and last session. The 71 subjects were assessed for their knowledge of diabetes, health behavior, the experience of self-measurement of blood glucose, body mass Index (BMI) and hemoglobin A1c (HbA1c) at before and after the program. They were also evaluated on their degree of utilization of blood glucose measurements after the program. Results: Each mean score on their knowledge of diabetes, health behavior and the experience of self-measurement of blood glucose was significantly increased from 14.77, 25.50, and 2.70 to 15.41, 28.40, and 4.81, respectively. Each mean score on both BMI and HbA1c (n=53) was significantly decreased from 24.47kg/m² and 7.27% to 24.01kg/m² and 6.67%, respectively. The post-HbA1c had a significant negative correlation(r=-0.415) with the degree of utilization of blood glucose measurements. The degree of utilization of blood glucose measurements had a significant positive correlation(r=0.581) with post-health behavior. Conclusions: The program shows effectiveness in improving HbA1c in Type 2 diabetes and pre-diabetes patients. The post-HbA1c might be related to the degree of utilization of blood glucose measurements which might be related to the health behavior.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.1
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• pp.5-10
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• 2012

In general, the fabrications of the LEDs with mesa structure are performed grown by MOCVD method. In order to etch and separate each chips, the LEDs are passed the RIE and scribing processes. The RIE process using plasma dry etching occur some problems such as defects, dislocations and the formation of dangling bond in surface result in decline of device characteristic. The SAG method has attracted considerable interest for the growth of high quality GaN epi layer on the sapphire substrate. In this paper, the SAG method was introduced for simplification and fabrication of the high quality epi layer. And we report that the size of selective area do not affect the characteristics of original LED. The diameter of SAG circle patterns were choose as 2500, 1000, 350, and 200 ${\mu}m$. The SAG-LEDs were measured to obtain the device characteristics using by SEM, EL and I-V. The main emission peaks of 2500, 1000, 350, and 200 ${\mu}m$ were 485, 480, 450, and 445 nm respectively. The chips of 350, 200 ${\mu}m$ diameter were observed non-uniform surface and resistance was higher than original LED, however, the chips of 2500, 1000 ${\mu}m$ diameter had uniform surface and current-voltage characteristics were better than small sizes. Therefore, we suggest that the suitable diameter which do not affect the characteristic of original LED is more than 1000 ${\mu}m$.

• Archives of Pharmacal Research
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• v.27 no.4
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• pp.390-395
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• 2004

The methanol extract obtained from the aerial parts of Aceriphyllum rossii (Saxifragaceae) was fractionated into ethyl acetate (EtOAc), n-BuOH and $H_2O$ layers through solvent fractionation. Repeated silica gel column chromatography of EtOAc and n-BuOH layers afforded six flavonol glycosides. They were identified as kaempferol 3-O-$\beta$-D-glucopyranoside (astragalin, 1), quercetin 3-O-$\beta$-D-glucopyranoside (isoquercitrin, 2), kaempferol 3-O-$\alpha$-L-rhamnopyranosyl $(1{\to}6)-\beta$-D-glucopyranoside (3), quercetin 3-O$\alpha$-L-rharnnopyranosyl $(1{\to}6)-\beta$-D-qlucopyrano-side (rutin, 4), kaempferol 3-O-[$\alpha$-L-rharnnopyranosyl $(1{\to}4)-\alpha$-L-rhamnopyranosyl $(1{\to}6)-\beta$-D-glucopyranoside] (5) and quercetin 3-O-[$\alpha$-L-rhamnopyranosyl $(1{\to}4)\alpha$-L-rhamnopyranosyl $(1{\to}6)\beta$-D-glucopyranoside] (6) on the basis of several spectral data. The antioxidant activity of the six compounds was investigated using two free radicals such as the ABTS free radical and superoxide anion radical. Compound 1 exhibited the highest antioxidant activity in the ABTS $\{2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)\}$ radical scavenging method. 100 mg/L of compound 1 was equivalent to $72.1\pm1.4\;mg/L$ of vitamin C, and those of compounds 3 and 5 were equivalent to $62.7\pm0.5\;mg/L$ and $54.3\pm1.3\;mg/L$ of vitamin C, respectively. And in the superoxide anion radical scavenging method, compound 5 exhibited the highest activity with an $IC_{50}$ value of $17.6{\pm}0.3{\mu}M$. In addition, some physical and spectral data of the flavonoids were confirmed.

• Geomechanics and Engineering
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• v.5 no.5
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• pp.379-399
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• 2013

In practice, analysis of laterally loaded piles is carried out using beams on non-linear Winkler springs model (often known as p-y method) due to its simplicity, low computational cost and the ability to model layered soils. In this approach, soil-pile interaction along the depth is characterized by a set of discrete non-linear springs represented by p-y curves where p is the pressure on the soil that causes a relative deformation of y. p-y curves are usually constructed based on semi-empirical correlations. In order to construct API/DNV proposed p-y curve for clay, one needs two values from the monotonic stress-strain test results i.e., undrained strength ($s_u$) and the strain at 50% yield stress (${\varepsilon}_{50}$). This approach may ignore various features for a particular soil which may lead to un-conservative or over-conservative design as not all the data points in the stress-strain relation are used. However, with the increasing ability to simulate soil-structure interaction problems using highly developed computers, the trend has shifted towards a more theoretically sound basis. In this paper, principles of Mobilized Strength Design (MSD) concept is used to construct a continuous p-y curves from experimentally obtained stress-strain relationship of the soil. In the method, the stress-strain graph is scaled by two coefficient $N_C$ (for stress) and $M_C$ (for strain) to obtain the p-y curves. $M_C$ and $N_C$ are derived based on Semi-Analytical Finite Element approach exploiting the axial symmetry where a pile is modelled as a series of embedded discs. An example is considered to show the application of the methodology.

• Membrane Journal
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• v.11 no.1
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• pp.38-49
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• 2001

The surface of polyimide membrane was modified by plasma treatment using Ar and NH~. and the permeability and selectivity for the mixture gas $(CO_2/N_2=20/80 vol%)$ were measured. The per¬meation experiments were performed by a variable volume method at $30^{\circ}$C and total pressure of 5 atm, The effect of the plasma conditions such as treatment time, power input, gas flow rate and pressure in the reactor on the transport Dwperties of modified membranes was investigated. The surface of the plasma treated membrane was analyzed by means of FTlR - ATH, ESCA and AFM. The dependences of the wettability and the etching on plasma treatment time were investigated by use of the contact angle and the weight loss measurement. Measurements of gas pcnneability characteristic were performed using both dry and wet membranes. The effects of experimental conditions such as temperature on the membrane performance were studied.

• Journal of the Korean Chemical Society
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• v.28 no.4
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• pp.205-209
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• 1984

The crystal and molecular structure of thiosinamine, $H_2NCSNHCH_2CHCH_2$, has been determined by X-ray diffraction method. The crystals are monoclinic, space group $P2_1/a$ with four molecules in a unit cell of dimensions, a = 9.819(3), b = 8.553(3), c = 9.170(2)${\AA}$, ${\beta}$ = 127.3(1)$^{\circ}$, and z = 4. Intensity data for 814 reflections were collected with a Rigaku-Denki automatic four circle diffractometer. The structure was solved by direct and Fourier methods. Refinements were carried out by full matrix least-squares method to a final R value of 0.046. The thiourea unit is planar, and the bond lengths and angles in that unit agree well with those in the compounds which contain a thiourea moiety. The molecules are linked together by the two patterns of N-H${\cdots}$S hydrogen bonds along the b-axis.

• Journal of Applied Biological Chemistry
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• v.59 no.2
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• pp.165-169
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• 2016

The quantitative analytical method for the bioactive substance, 3-cyano-4-methoxy-N-methyl-2-pyridone (ricinine) and an index compound, ricinoleic acid in castor plant (Ricinus communis) extract or oil was developed. For the determination of a pyridone alkaloid compound, ricinine, successive cartridge cleanup method combined with ultra-performance liquid chromatography was set up with $ENVI-Carb^{TM}$ (0.5 g) and $C_{18}$ SPE cartridges. Accuracy and precision were evaluated through fortification studies of one biopesticide (PE) at 10 and $100mg\;kg^{-1}$. Mean recoveries of ricinine were 98.7 and 96.0 % associated with less than 10 % RSD, respectively. For the determination of ricinoleic acid in castor extract and oil, saponification and methylation were optimized using gas chromatography-time of flight mass spectrometry. Recovery was more than 84.8 % associated with 6.2 % RSD after derivatization procedure. Both methodologies developed were applied to analyze real samples including three castor oil products and six commercially available biopesticides containing R. communis, collected at Korean market. The contents of ricinine and ricinoleic acid in most commercial biopesticides were less than the oil or extract contents indicated by label.

• Journal of Korean Society on Water Environment
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• v.35 no.5
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• pp.425-431
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• 2019

Recently, people have been attracting attention to the good quality of water resources as well as water welfare. to improve the quality of life. This study is a papers on the prediction of benthic macroinvertebrate index (BMI), which is a aquatic ecological health, using the machine learning based CFS (Correlation-based Feature Selection) method and the random forest model to compare the measured and predicted values of the BMI. The data collected from the Han River's branch for 10 years are extracted and utilized in 1312 data. Through the utilized data, Pearson correlation analysis showed a lack of correlation between single factor and BMI. The CFS method for multiple regression analysis was introduced. This study calculated 10 factors(water temperature, DO, electrical conductivity, turbidity, BOD, $NH_3-N$, T-N, $PO_4-P$, T-P, Average flow rate) that are considered to be related to the BMI. The random forest model was used based on the ten factors. In order to prove the validity of the model, $R^2$, %Difference, NSE (Nash-Sutcliffe Efficiency) and RMSE (Root Mean Square Error) were used. Each factor was 0.9438, -0.997, and 0,992, and accuracy rate was 71.6% level. As a result, These results can suggest the future direction of water resource management and Pre-review function for water ecological prediction.