• The Korean Journal of Pesticide Science
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• v.14 no.1
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• pp.1-9
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• 2010

In order to survey residual characteristics of pesticides in the agricultural products selling at markets and to assess their safety, a total of 120 agricultural products were collected from the wholesale and traditional markets in Cheongju and analyzed the pesticide residues in them by multiresidue analysis method using GLC, HPLC and GC-MSD. Three pesticides, procymidone, penconazole, and tetraconazole, were detected from 4 samples such as onion, leek, tomato, and green pepper. Fungicide penconazole was detected from the onion collected from wholesale market. Fungicide procymidone was detected from leek and tomato and fungicide tetraconazole was detected from green pepper. Pesticide residues were detected from 3.3% of the total samples. The estimated daily intakes (EDIs) of the pesticides detected were less than 0.1% of their acceptable daily intakes (ADIs), representing that residue levels of the pesticides detected were evaluated as safe.

• Journal of Korean Orthopaedic Sports Medicine
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• v.6 no.1
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• pp.50-56
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• 2007

Purpose: To evaluate the aspect of occurrence and transition of the elbow injuries in baseball players from childhood to adult. Materials and Methods: We had a survey and took the simple X-ray from the anteroposterior view and the lateral view of both elbows for subjects of total 320 baseball players. - each of 80 players in elementary school, middle school, high school, and professional baseball players between January and December in 2004. Results: The region of pain and the bony changes in elbow were the most frequent in medial side from all the groups of players. Especially, hypertrophy of medial epicondyle were the most numerous. As baseball players got older, the radiological changes of elbow were increased. The bony changes were found out 52 cases (65%) of the elementary school players, 66 cases (82%) of the middle school players, 68 cases (85%) of the high school players and 70 cases (88%) of the professional players out of the total 320 baseball players. Conclusion: The bony changes of the elbow in baseball players got frequent as they were getting older and increased in comparison with past.

• Journal of the Korean Vacuum Society
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• v.2 no.2
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• pp.236-245
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• 1993

Single crystals, SbSI : V, SbSeI : V, BiSI : V, BiSeI : V, SbSI : Cr, SbSeI : Cr, BiSI : Cr, BiSeI : Cr, SbSI : Ni, SbSeI : Ni, BiSI : Ni, and BiSeI : Ni were grown by the vertical Bridgman method. It is found that the grown single crystals have an orthorhombic structure and the indirect optical transitions. The temperature dependence of energy gap shows the two reflection point related with the phase transitions and is well fitted with Varshni equation in the continuous region. The optical absorption peaks due to the doped impurities (V, Cr and Ni) are respectively attributed to the electron transitions between the split energy levels of $V^{+2}$, $Cr^{+2}$ and $Ni^{+2}$ ions sited at $T_d$ symmetry of the host lattice.

• Journal of the Korean Vacuum Society
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• v.2 no.2
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• pp.227-235
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• 1993

$SbS_{1-x}Se_xI,\;BiS_{1-x}Se_xI,\;Sb_{1-x}Bi_xSI,\;Sb_{1-x}Bi_xSeI,\;SbS_{1-x}Se_xI:Co,\;BiS_{1-x}Se_xI:Co,\;Sb_{1-x}Bi_xSI:Co$, and $Sb_{1-x}Bi_xSeI:Co$ single crystals were grown by the vertical Bridgman method using the ingots. It has been found that these single crystals have an orthorhombic structure and indirect optical transition. The composition dependences of energy gaps are given by $E_g(x)=E_g(0)-Ax+Bx^2$. The impurity optical absorption peaks due to cobalt deped with impurity are attributed to the electron transitions between the split energy levels of $Co^{2+}$ and $Co^{3+}$ ions sited at $T_d$symmetry of the host lattice.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.775-786
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• 2017

Monitoring sediment flux is crucial especially for maintaining river systems to understand morphological behaviors. Recently, hydroacoustic backscatter (or SNR) as a surrogate to empirically estimate suspended sediment concentration has been increasingly highlighted for more efficient acquisition of sediment dataset, which is difficult throughout direct sediment sampling. However, relevant contemporary researches have focused on wide range solution applicable for large natural rivers where H-ADCPs with relatively low acoustic frequency have been widely utilized to seamlessly measure streamflow discharge. In this regard, this study aimed at investigating hydroacoustical characteristics based on a very recently released H-ADCP (SonTek SL-3000) with high acoustic frequency of 3 MHz in order to capitalize its capacity to be applied for suspended sediment monitoring in laboratory conditions. SL-3000 was tested in a laboratory flume to collect SNR in conjunction with LISST-100X for actual sediment concentration and particle distribution in both sand and silt sediment injection in various amount. Conventional algorithms to correct signal attenuations for water and sediment were carefully tested to validate whether they can be applied for SL-3000. As result of analyzing the SNR-SSC correlation trand, through further study in the future, it is confirmed that SSC can be observed indirectly by using the SNR.

• Journal of Sensor Science and Technology
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• v.21 no.3
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• pp.223-228
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• 2012

In this study, a fiber-optic pH sensor based on a pH sol-gel film is fabricated. The sol-gel film is made by co-polymerizing tetramethoxysilane, trimethoxymethylsilane, ethanol and distilled water. As a pH indicator, a neutral red is immobilized in a thin porous film formed by the sol-gel process. The pH change in a sensing probe gives rise to a change in the color of the pH sol-gel film, and the absorbance of reflected light through the pH sol-gel film is also changed. By using a spectrometer, therefore, the spectra of reflected lights in the sensing probe with different pH values are measured. Also, the relationships between the pH values and the absorbance are analyzed on the basis of the color variations of the pH sol-gel films. In repeated experiments, the fiber-optic pH sensor shows that it has reversibility, a high reproducibility and a wide absorbance change in a pH range from pH 5 to 9. Also, we confirmed that the fabricated pH sol-gel film exhibits a fast response time, little or no pH indicator leaching and a dynamic range of 2.04 dB from pH 5 to 9. Based on the results of this study, a fiber-optic pH sensor can be developed for the pH monitoring in the harsh environments.

• Korean Journal of Food Science and Technology
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• v.17 no.6
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• pp.500-505
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• 1985

A method to store concentrated milk in the liquid state at $-15^{\circ}C$ was developed, and quality changes during storage of milk were evaluated. Combined cryoprotectants (CCP) suitable for storing concentrated milk in the liquid state at $-15^{\circ}C$ were consisted of 17.74% sucrose, 8.87% glucose, 8.87% fructose, 2% glycerol, 0.25% sodium hexametaphosphate, 0.25% NaCl and 0.02% ascorbic acid. The amount of CCP to be added to concentrated milk to depress freezing point to $-15^{\circ}C$ was 38% by weight. Gelation due to protein denaturation was the most serious quality change during storage, which adversely affected appearance and utilization of the stored product. Gelation was observed after 3 weeks storage in the control, but it was not in milk with CCP throughout 18 weeks storage. Amount of protein precipitated increased in the control during storage, whereas there was no protein precipitated in milk with CCP. Surface color and peroxide value of the control and treatment did not change significantly during storage, and there were no marked differences between the control and treatment. These results indicated that quality of concentrated milk could be preserved, without gelation, by storing milk with CCP in the -liquid state at the frozen storage temperature. Besides, energy required for freezing preservation of milk could be significantly reduced by elimination of phase changes for freezing and thawing, and the stored product could be continuously processed for the final products without long waiting time for thawing.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.2 s.29
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• pp.103-110
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• 2007

This study estirmted the appropriate pollutant load reduction from point sources in Jinhae Bay, Korea, using an eco system model. The results of COD values in the inner part of the bay obtained through the simulation by ecosystem model were greater than 3.0mg/L, and exceeded the limits of Korean Coastal Water Quality Grade III. Engineering countermeasures to reduce the $70\sim90%$ of all land based pollution load or organic and inorganic material loads from point sources by more than 50% were required to keep the COD levels below 2 mg/L. The reduction loads is 5,632kg/day of COD, 481kg/day of DIP and 7,991 kg/day of DIN in case of the reduction of both the organic and nutrients. The estimated environmental currying capacity of that case is 13,112kg/day of COD, 206kg/day of DIP and 3,425kg/day of DIN to keep the COD levels below 2mg/L.

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.249-258
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• 2012

Integral and rigid frame bridges have advantages in bridge maintenance and structural efficiency by eliminating expansion joints and bridge supports. However, the detail of typical girder-abutment connection is rather complex and increases construction cost depending on construction detail. For the purpose of compensating disadvantages such as complexity and additional cost, a new type of bridge is proposed in this study, which improves the efficiency of construction by simplifying the construction detail of girder-abutment connection. The proposed bridge has the connection detail of steel girder and abutment integrated by prestressed PS bar installed in the connection. In this study, finite element analysis and fatigue load test are conducted to evaluate the fatigue capacity of the proposed girder-abutment connection. The results of the finite element analysis revealed that the possibility of the fatigue damage in the girder-abutment connection is very low. The results of the fatigue load test verified that the integrity of the girder and abutment connection is maintained after 2,000,000 cycles of fatigue loading.

• Journal of Electrochemical Science and Technology
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• v.1 no.1
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• pp.19-24
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• 2010

Alloying degree is an important structural factor of PtRu catalysts for direct methanol fuel cells (DMFC). In this work, carbon supported PtRu catalysts were synthesized by reduction method using anhydrous ethanol as a solvent and $NaBH_4$ as a reducing agent. Using anhydrous ethanol as a solvent resulted in high alloying degree and good dispersion. The morphological structure and crystallanity of synthesized catalysts were characterized by X-ray diffraction (XRD), high resolution transmission electron microscope (HR-TEM). CO stripping and methanol oxidation reaction were measured. Due to high alloying degree catalyst prepared in anhydrous ethanol, exhibited low onset potential for methanol oxidation and negative peak shift of CO oxidation than commercial sample. Consequently, samples, applying ethanol as a solvent, exhibited not only enhanced CO oxidation, but also increased methanol oxidation reaction (MOR) activity compared with commercial PtRu/C (40 wt%, E-tek) and 40 wt% PtRu/C prepared in water solution.