• Journal of fish pathology
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• v.28 no.2
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• pp.79-85
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• 2015

A specimen of porous-head eelpout Bothrocara hollandi (Zoarcidae: Perciformes) caught from the East Sea was found to harbour a myxosporean parasite. Numerous whitish pseudocysts were scattered throughout the body musculature of this individual specimen. Fresh myxosporean spores were found from the squashed pseudocysts under light microscopy. They were subspherical in frontal view with a length of $11.9(11.0{\sim}13.5){\mu}m$, width of $11.6(10.7{\sim}13.6){\mu}m$, and thickness of $7.8(6.9{\sim}8.8){\mu}m$. Two polar capsules were almost equally pyriform with a length of $4.4(3.2{\sim}5.3){\mu}m$ and width of $3.3(2.4{\sim}4.2){\mu}m$. Morphometric and host ecology analysis revealed that this myxosporean parasite could be identified as Myxobolus aeglefini Auerbach 1906. Phylogenetic analysis based on 18S rDNA sequences also revealed that M. aeglefini was clustered with M. albi and M. groenlandicus in the same branch, sharing 97.7% and 96.9% sequence similarities with M. albi and M. groenlandicus, respectively.

• Journal of Korean Society of Steel Construction
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• v.15 no.2
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• pp.125-135
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• 2003

A 3-dimensional model of curved steel box girder bridges without diaphragm was presented. This model yielded results that were consistent with those of the parameter analysis using the BEF and Ritz methods. Se veralmodels with diaphragms were analyzed to estimate the appropriate diaphragm spacing. In case of 50m span, models A-10, A-20, A-30, B-10, B-20, and B-30 were found to have 5(8.3m), 7(6.25m), 8(5.5m), 4(10m), 6(7.1m), and 7(6.25m) diaphragms, respectively. In addition, a formula that presents the ratio of distortional stress to bending stresswas created from the results of the 3-dimensional FEM model analysis.

• Tunnel and Underground Space
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• v.15 no.4 s.57
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• pp.296-304
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• 2005

This study is to observe stray currents generated around the steel tower by domestic transmission network system and analysis stability of electric detonator. It is measured the stay current of each ten place at steel tower of 765 kV, 345 tV, 154 tV transmission line among domestic transmission network system. Stay currents measured a total of 40m at intervals of 4m toward a line direction and a line vertical direction centering around steel tower. Temperature of the surface, EC, water content also are measured. Although stay currents show the highest values, that is 12 percent of at 4m and less than 1 percent of 40m with Institute of Makers of Explosives(IME) regulations. It is shown correlation between stay currents and water content$\cdot$EC$\cdot$temperature of the surface. Stay currents measured at line direction and line vertical direction were little different and the shape of diminution was also shown a similar aspect.

• Journal of the Korean Ceramic Society
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• v.44 no.4 s.299
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• pp.198-201
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• 2007

Multi-walled carbon nanotube (M-CNT)/Nafion nanocomposites were prepared by solution casting to elucidate the effect of M-CNT addition, from 0 to 7 wt%, on the viscoelastic behavior of the composites. The M-CNT bundles induced by the Nafion polymer were determined to be uniformly distributed for the 1 wt% M-CNT/Nafion nanocomposites. The 1 wt% M-CNT/Nafion composite exhibited the highest blocking stress of 2.3 kPa due to its high elastic modulus of 0.485 GPa. From a dynamic mechanical analysis, the 1 wt% M-CNT had the highest storage and loss moduli compared with the other samples in all frequency and temperature ranges. From the storage modulus data, the M-CNT loaded composites had similar $T_g$ values near $120^{\circ}C$. The glass transition temperatures of the M-CNT loaded composites were $120^{\circ}C$ (1 wt%), $117^{\circ}C$ (3 wt%), $117^{\circ}C$ (5 wt%), and $135^{\circ}C$ (7 wt%), suggesting that the effect of the M-CNTs on the Nafion film begins at 1 wt%. Thus, it has been concluded that the 1 wt% M-CNT disported composite is attractive for actuator applications.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.475-479
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• 1996

Diethylcarbamazine (DEC, 1-diethylcarbamyl-4-methylpiperazine) is an antiparasitic piperazine derivative used in the treatment of lymphatic filariasis caused by Wuchereria bancrofti, Brugia malayi or grugia timori. DEC-N-oxide is a major metabolite in humans and has antifilarial activity. In carrying out pharmacokinetic studies, gas chromatographic analysis of DEC in plasma can be complicated by the presence of the metabolite, since the thermally unstable DEC-N-oxide is converted back to a material which coelutes with DEC under the conditions of the analysis. We now report a method to separate DEC-N-oxide from DEC in plasma using solid phase extraction with subsequent gas chromatographic analysis using a nitrogen specific detector. One-diethylcarbamyl-4-ethylpiperazine (E-DEC) was the internal standard. The standard curve of DEC was linear in the range of 10 to 200 ng/ml as described by Y=0.0350+0.0128X, $R^2=0.999$. The limit of quantitation was 4 ng/mL. Reproducibility at 10, 100 and 200 ng/mL concentration points of the standard curve gave coefficient variations of 6.1%, 7.8% and 1.6%, respectively. The recovery following solid phase extraction was 99.3% for DEC and 94.8% for the internal standard. This sensitive and specific analytical method is suitable for pharmacokinetic studies of DEC.

• Advances in concrete construction
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• v.11 no.4
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• pp.285-298
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• 2021

This study focused on experimental evaluation of mechanical properties of pervious concrete mixtures with the aim of achieving higher values of strength while considering the associated costs. The effectiveness of key parameters, including cement content, water to cement ratio (W/C), aggregate to cement ratio (A/C), and sand replacement was statistically analyzed using paired-samples t-test, Taguchi method and one-way ANOVA. Taguchi analysis determined that in general, the role of W/C was more significant in increasing strength, both compressive and flexural, than cement content and A/C. It was found that increase in replacing percent of coarse aggregate with sand could undermine specimens to percolate water, though one-way ANOVA analysis determined statistically significant increases in values of strength of mixtures. Cost analysis revealed that higher strengths did not necessarily correspond to higher costs; in addition, increasing the cement content was not an appropriate scenario to optimize both strength and cost. In order to obtain the optimal values, response surface method (RSM) was carried out. RSM optimization helped to find out that W/C of 0.40, A/C of 4.0, cement content of about 330 kg/m3 and replacing about 12% of coarse aggregate with sand could result in the best values for strength and cost while maintaining adequate permeability.

• Journal of Power System Engineering
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• v.12 no.1
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• pp.28-34
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• 2008

가스-액체 이젝터에 관한 수치해석은 3차원 CFD 모델로 수행하였다. 본 논문에서는 이젝터의 유동특성과 질량전달특성에 대한 작동조건과 이젝터의 기하학적 모형의 영향에 관한 연구를 수행하고자 한다. CFD 결과 실험 데이터에 의하여 검증되었으며, 유동 분석과 이젝터 성능의 예측 또한 실행되었다. 작동상태의 변화는 0.2 $\sim$ 1.2 범위에서 가스-액체 유량비를 변화시킴으로서 주어진다. 혼합관의 $L_M/D_M$이 4 $\sim$ 10의 범위에서 변화를 주었다. CFD 연구는 길이와 직경비가 5.5일 때 체적 유량전달계수는 가스 유량이 증가함에 따라 증가한다는 것을 나타낸다. 동시에 $L_M/D_M$가 4일 때 체적유량전달계수는 기체-액체 유량비가 0.6에서 최대치에 도달한다. 또한, 체적 유량전달계수는 혼합 튜브길이가 증가함에 따라 감소한다.

• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.3
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• pp.176-182
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• 2020

Purpose: To evaluate the effects of load direction, number of implants, and alignment of implant position on stress distribution in implant, prosthesis, and bone tissue. Materials and Methods: Four 3D models were made to simulate posterior mandible bone block: two implants and 3-unit fixed dental prosthesis (FDP) with a pontic in the center (model M1), two implants and 3-unit FDP with a cantilever pontic at one end (model M2), FDP supported by three implants with straight line placement (model M3) and FDP supported by three implants with staggered implant configuration (model M4). The applied force was 120 N axially or 120 N obliquely. Results: Peak von Mises stresses caused by oblique occlusal force were 3.4 to 5.1 times higher in the implant and 3.5 to 8.3 times higher in the alveolar bone than those stresses caused by axial occlusal force. In model M2, the connector area of the distal cantilever in the prosthesis generated the highest von Mises stresses among all models. With the design of a large number of implants, low stresses were generated. When three implants were placed, there were no significant differences in the magnitude of stress between staggered arrangement and straight arrangement. Conclusion: The effect of staggering alignment on implant stress was negligible. However, the number of implants had a significant effect on stress magnitude.

• Journal of Periodontal and Implant Science
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• v.53 no.4
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• pp.259-268
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• 2023

Purpose: Hyaluronic acid (HA) affects angiogenesis and promotes the migration and differentiation of mesenchymal cells, thereby activating the osteogenic ability of osteoblasts. Although studies on the action of HA during bone regeneration are being actively conducted, the optimal dose of HA required for bone regeneration remains unclear. Therefore, the purpose of this study was to elucidate the most effective HA dose for bone formation using a rat critical-size defect model. Methods: Thirty rats were randomly divided into 5 groups, with 6 rats in each group. An absorbable collagen sponge soaked with HA or saline was used to fill an 8-mm defect, which was then covered with a collagen membrane. Different treatments were performed for each group as follows: (1) saline control, (2) 1 mg/mL HA, (3) 25 mg/mL HA, (4) 50 mg/mL HA, or (5) 75 mg/mL HA. After a healing period of 4 weeks, micro-computed tomography and histological analysis were performed. The obtained values were analyzed using analysis of variance and the Tukey test (P<0.05). Results: At week 4, the 75 mg/mL HA group had the highest bone volume/total volume ratio, new bone, and bone fill among the 5 groups, and these values were significantly different from those observed in the control group (P<0.01) and 1 mg/mL HA group (P<0.001). More active bone formation was observed in the higher-dose HA groups (25 mg/mL, 50 mg/mL, and 75 mg/mL HA), which included a large amount of woven bone. Conclusions: The 75 mg/mL HA group showed better bone formation than the other groups (1, 25, and 50 mg/mL HA and control).

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.10 no.1
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• pp.208-222
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• 2000

This study was conducted to supplement limit of previous study, The objectives of this study were to select optimal conditions of high performance liquid chromatography(HPLC) operation for detecting urinary 2-thiothiazolicline-4-carboxylic acid(TTCA) and thiocarbamide simultaneously, and to evaluate recovery rates for various liquid-liquid extration method of these metabolites, The results are as follows : 1. The urinary TTCA and thiocarbamide were separate sharply when flow rate is $0.7m{\ell}/min$, using a series $C_8$ and $C_{18}$ column, 50 mM $KH_2PO_4$ : acetonitrile (93.5 : 6.5) and pH 3.5 as a mobile phase. The retention time was TTCA, $12.07{\pm}0.11$(mean${\pm}$SD, n=06), thiocarbamide, $7.85{\pm}0.01$ (mean${\pm}$SD, n=6), respectively. The calibration curve for TTCA and thiocarbamide was linear within the range 0.05 to $30{\mu}g/m{\ell}$. 2. By the liquid-liquid extration, butanol extration with $(NH_4)_2$ as a salting-out reagent was used as a simultaneous extration method for these metabolites in acid state, and recovery rates of this method are urinary TTCA, $49.6{\pm}17.7$ (mean${\pm}$SD, n=16), thiocarbamide, $43,9{\pm}5.50$ (mean${\pm}$SD, n=16), respectively 3. The precision(pooled coefficients of variation for 4 concentration) of the urinary thiocarbamide analysis was 0.03754 by butanol liquid-liquid extraction with $(NH_4)_2$ as a salting-out reagent, and TTCA was 0.04082 by ethyl acetate liquid-liquid extration with $(NH_4)_2$ as a salting out reagent The above results show that the butanol liquid-liquid extraction with $(NH_4)_2$ as a salting-out reagent in acid state, and using a series $C_8$ and $C_{18}$ column, 50 mM $KH_2PO_4$ : acetonitrile (93.5 : 6.5) and pH 3.5 as a mobile phase are suitable for the analysis of urinary TTCA and thiocarbamide simultaneously. The detection limit of TTCA and thiocarbamide was about $0.17{\mu}g/m{\ell}$, $0.07{\mu}g/m{\ell}$.