• Computers and Concrete
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• 제13권1호
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• pp.17-30
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• 2014

This research presents the effect of various ground pozzolanic materials in blended cement concrete on the strength and chloride penetration resistance. An experimental investigation dealing with concrete incorporating ground fly ash (GFA), ground bottom ash (GBA) and ground rice husk ash (GRHA). The concretes were mixed by replacing each pozzolan to Ordinary Portland cement at levels of 0%, 10%, 20% and 40% by weight of binder. Three different water to cement ratios (0.35, 0.48 and 0.62) were used and type F superplasticizer was added to keep the required slump. Compressive strength and chloride permeability were determined at the ages of 28, 60, and 90 days. Furthermore, using this experimental database, linear and nonlinear multiple regression techniques were developed to construct a mathematical model of chloride permeability in concretes. Experimental results indicated that the incorporation of GFA, GBA and GRHA as a partial cement replacement significantly improved compressive strength and chloride penetration resistance. The chloride penetration of blended concrete continuously decreases with an increase in pozzolan content up to 40% of cement replacement and yields the highest reduction in the chloride permeability. Compressive strength of concretes incorporating with these pozzolans was obviously higher than those of the control concretes at all ages. In addition, the nonlinear technique gives a higher degree of accuracy than the linear regression based on statistical parameters and provides fairly reasonable absolute fraction of variance ($R^2$) of 0.974 and 0.960 for the charge passed and chloride penetration depth, respectively.

• Journal of Pharmaceutical Investigation
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• 제28권4호
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• pp.267-274
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• 1998

Biphenyl dimethyl dicarboxylate (DDB) has been used for the treatment of acute and chronic hepatitis. However, its poor solubility in water, $2.5\;{\mu}g/ml$, caused low bioavailability of the drug after its oral administration. In order to increase the dissolution of DDB in gastrointestinal tracts, consequently to increase the bioavailability of the drug, DDB tablet was prepared with solid dispersion of DDB with poloxamer 338 or 407 using a direct compression method. To improve the flowability of the solid dispersion, Aerosil was used as an adsorbent. The effect of formulation variables (poloxamer and Aerosil contents) on the dissolution rate of DDB from tablets was investigated using an analysis of variance. The dissolution rate of DDB from tablets was evaluated with KP II (paddle) method. The dissolution patterns of the drug from the tablet prepared with poloxamer 407 were affected significantly by the contents of poloxamers and Aerosil over the range employed, but those of the drug from the tablet prepared with poloxamer 338 were not. The optimum formulation of the DDB tablet, showed the same dissolution pattern as that of the reference, was obtained after polynomial equations of drug dissolution profiles for each formula were fitted to contour plots. The optimum formulation ratios of DDB:poloxamer 407:Aerosil were 1:2.5:2.5 and 1:5:5.

• Archives of Pharmacal Research
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• 제18권4호
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• pp.237-242
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• 1995

For the vioequivalence study of two ceftriaxone injection formulations ($Rocephin{\circledR}$ ; Roche, and Triaxone ; Hanmi0, the HPLC analytical method for the analysis of ceftriaxone in plasma was used. Fourteen healthy volunteers completed the study and each subject were IM in jected signle doses (1 g) of the test and the reference formulations in a two-way crossover design with an one week drug free interval between doses. Following each administration, plasma concentrations of ceftrixone were monitored over a period of 24 h. Bioequivalence parameters $AUC_{24th}, {\;}T_{max}, {\;}C_{max}$ and MRT determined from the data obtained for the two formulations were examined by analyses of variance (ANOVA) and other criteria and tests for bioequivalence. Results of ANOVA and confidence limits of test/reference ratios of $AUC_{24th}, {\;}T_{max}, {\;}C_{max}$ and MRT, and statistical tests indicated the bioequivalence of the two formulations (i.e., test/reference ratio was within $100{\pm}20%$) except for $T_{max}$ The mean of $T_{max}$ showed only 6. 9% difference from the reference but the detection limit was 22.5% which is slightly over the 20% criteria. No pharmacokinetic parameters including Ka, Kel, Vd and Cl indicated significant difference in between the two fomulations. It was concluded that the data yielded fro the two cefriaxone formulations demonstrated that they were bioequivalent.

• Journal of Ecology and Environment
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• 제29권5호
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• pp.433-438
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• 2006

To elucidate the mechanisms by which algal food quality affect Daphnia growths, we measured carbon incorporation rates and respiration rates of Daphnia magna with Cryptomonad Rhodomonas minuta, green algae Scenedesmus acutus and cyanobacteria Synechococcus sp. with varying physiological states as food. Carbon assimilation rates were high with R. minuta and S. acutus and low with Synechococcus sp. showing a similar pattern to the growth rate pattern. There was no clear difference among respiration rates of three algal species. Carbon assimilation rates and respiration rates of D. magna appeared to be independent on Molar C:P ratios in algal foods. Carbon growth efficiencies (incorporated carbon per assimilated carbon amount) were lower when D. magna fed with Synechococcus sp. than fed with R. minuta or S. acutus. Analysis of variance results show that carbon assimilation rates which were sum of incorporation and respiration rates and carbon growth efficiencies were only dependant on species affiliation. Overall, our results showed that algal species with varying ${\omega}3$ polyunsaturated fatty acid content led different carbon incorporation rates and overall carbon assimilation rates of D. magna.

• 대한구순구개열학회지
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• 제10권1호
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• pp.39-56
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• 2007

The bilateral cleft lip, a more severe form of clefting than unilateral cleft lip, involves separation of the lip along philtral lines, isolating the central segment (prolabium). Bilateral cleft lip may be either symmetrical or asymmetrical, in which case the cleft lip is split more on one side than on the other. The cleft affects the obvious facial form as an anatomic deformity and has functional consequences, affecting the child's ability to eat, speak, hear, and breathe. Although there would seem to be quite a variance in reported figures, ratios of cleft lip with or without cleft palate have gone as high as 1:500 and as low as 1:1000. It is known that less than 10% of cleft lips are bilateral. Although bilateral cleft lip is less common than unilateral cleft lip, the deformity is more severe, and the reconstructive technique is more complex. Surgery is the only treatment necessary for patients with bilateral cleft lip. Accompanying the evolution of surgical repair is the increasingly important role of orthodontic support with early presurgical alveolar and nasal molding. Repositioning the maxillary and alveolar segments into a more anatomic position allows the surgeon to repair the lip and associated nasal deformity under more optimal conditions. The purpose of this article is to review the related anatomy, presurgical management, and surgical management of bilateral cleft lip.

• 근관절건강학회지
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• 제17권2호
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• pp.142-150
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• 2010

Purpose: The purpose of this study was to examine EMG activities and VMO/VL ratio of the vastus medialis oblique, vastus lateralis, and rectus femoris during squat exercise (knee angle: 15, 45, and 60 degrees; tibial rotation: internal rotation, neutral, and external rotation). Methods: Twelve subjects performed squat exercise at each knee angle and tibial rotation while electromyographic (EMG) activity was collected. Statistical analysis consisted of two-way repeated measures analysis of variance with post hoc analysis. Results: There were significant main effects of knee angles and foot positions and interaction effect on EMG activities of vastus medialis oblique and vastus lateralis. VMO/VL ratios were significantly different by tibial rotations and there was an interaction effect. A neutral position produced significantly more VMO/VL activity ratio than that from internally rotated position and externally rotated position at 60 degrees. Conclusion: Considering the interaction effects for EMG activity across quadriceps muscles tested, the 60 degrees knee angle with a neutral foot position may provide the most effective condition for patients with acute patellofemoral syndrome.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권10호
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• pp.4808-4824
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• 2016

Signal individual reconnaissance and identification is an extremely important research topic in non-cooperative domains such as electronic countermeasures and intelligence reconnaissance. Facing the characteristics of the complexity and changeability of current communication environment, how to realize radiation source signal individual identification under the low SNR conditions is an emphasis of research. A novel emitter individual identification method combined bi-spectrum analysis with wavelet feature is presented in this paper. It makes a feature fusion of bi-spectrum slice characteristics and energy variance characteristics of the secondary wavelet transform coefficient to identify MFSK signals under the low SNR (signal-to-noise ratios) environment. Theoretical analyses and computer simulation results show that the proposed algorithm has good recognition performance with the ability to suppress noise and interference, and reaches the recognition rate of more than 90% when the SNR is -6dB.

• 한국기계가공학회지
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• 제18권11호
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• pp.76-82
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• 2019

This study aims to find the shapes of an end-mill with low cutting temperature during the end-mill process of Ti-6Al-4V alloy. Such ${\alpha}-{\beta}$ titanium alloys are increasingly more used for their high tensile strength and high corrosion resistance. The cutting characteristics of Ti-6Al-4V alloy were studied using an analytical method validated by comparing the estimated cutting resistance with that from experiments. The end-mill shape was analyzed using an experimental method. The end-mill shape with low cutting resistance and low cutting temperature was confirmed by analyzing the signal-to-noise ratios for various conditions. Then, the factors with significance factor of 95% or more were determined in the variance analysis. Finally, an end-mill shape that can ensure a low cutting temperature was proposed.

• Computers and Concrete
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• 제21권6호
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• pp.681-695
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• 2018

This pioneer study investigates the size effect on the compressive and tensile strengths of fiber-reinforced self-compacting concrete (FR-SCC) with different specimens, before and after exposure to elevated temperatures. 432 self-compacting concrete (SCC) specimens with two concrete grades (50 and 80MPa) and three steel fiber ratios (0%, 0.5% and 1%) were prepared and tested. Moreover, based on the experimental results, new formulations were proposed to predict the residual strengths for different specimens. A parametric study was also carried out to investigate the accuracy of proposed formulations. Residual strength results showed that the cylinder specimen with dimensions of $100{\times}200mm$ was the most affected, while the cube with a size of 100 mm maintained a constant difference with the standard cylinder ($150{\times}300mm$). Temperature effect on the cube specimen (150 mm) was the least in comparison to other specimen sizes and types. In general, provision of steel fibers in SCC mixtures resulted in a reduction in temperature effect on the variance of a conversion factor. Parametric study results confirm that the proposed numerical models are safe to be used for all types of SCC specimens.

• Environmental Engineering Research
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• 제24권1호
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• pp.24-30
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• 2019

The present study explores the applicability of response surface methodology (RSM) in conjunction with central composite design (CCD) matrix to statistically optimize ettringite crystallization process for the removal of sulphate from landfill leachate. A three factor-five coded level CCD with 20 runs, was performed to estimate the best fitted model. The RSM results indicated that the fitted quadratic regression model could be appropriate to predict sulfate removal efficiency. The pH was identified as the most dominant parameter affecting sulphate removal. 61.6% of maximum sulphate removal efficiency was obtained at pH of 11.06 for a 1.87 of $Ca/SO_4$ and 0.51 of $Al/SO_4$ molar ratios. The operating cost for ettringite crystallization at optimized conditions was calculated to be 0.52 $/$m^3$. The significance of independent variables and their interactions were tested by analysis of variance. Scanning electron microscope (SEM) and SEM coupled with energy dispersive X-Ray spectroscopy results confirmed the formation of ettringite crystal and were used to describe its morphology features.