• Polymer(Korea)
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• v.38 no.3
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• pp.293-298
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• 2014

We prepared hydrophilic porous supporters for the reinforced composite fuel cell membrane by radiation grafting of acrylonitrile (AN) and hydrophilic sodium allylsulfonate (SAS) into a porous polytetrafluoroethylene (PTFE) supporter. The physicochemical properties of the supporters prepared under various reaction conditions such as molar ratio of SAS/AN, monomer concentration, and irradiation dose were evaluated. FTIR was utilized to confirm the successful introduction of SAS/AN copolymer chains into the porous PTFE. The pores of the porous PTFE film were found to be decreased with an increase in the degree of grafting by using FE-SEM and gurley number. Furthermore, by analyzing the degree of grafting, contact angle, and TBO (toluidine blue O) uptake, the hydrophilicity of the prepared supporters was found to increase with an increase in the degree of grafting.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.225-229
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• 2017

Micron-sized dextran particles, which now attract wide attention as a promising drug delivery systems, can be prepared via the supercritical anti-solvent (SAS) process. In SAS process, dextran particles are obtained as a result of recrystallization of dissolved dextran in dimethyl sulfoxide (DMSO) on addition of supercritical $CO_2$ as an anti-solvent. In this work, with an intention to provide information on the feasible operating conditions of the process, the phase behavior of Dexran/DMSO/$CO_2$ is observed by measuring the cloud point in favor of a variable volume cell. From the experimental study, it is concluded that a feasible operating condition of the SAS process for preparation of dextran particles would be 300.15 K~330.15 K and 90 bar~130 bar, respectively, and solute concentration ranges from 5mg/ml to 20 mg/ml.

• Journal of Digital Convergence
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• v.19 no.11
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• pp.415-424
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• 2021

The purpose of the current study is to to examine the psychometric properties of the Subjective Agingwell Scale (SAS). Three hundred and forty two elders completed the SAS and the scales assessing subjective well-being, optimism, perceived control and adhering to healthy behavior. The 11-item SAS that displays good internal reliability and good fit to the three-factor model consisting of cognitive satisfaction, positive affect, and spiritual fullness. Correlational analyses with measures of subjective agingwell, subjective well-being, and optimism provide evidence for construct validity. Moreover, the results from hierarchical regression analyses show criterion-related validity of the SAS. This scale could be used in the field to measure and promote subjective agingwell.

• Wind and Structures
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• v.37 no.4
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• pp.303-314
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• 2023

In this study, two steady RANS turbulence models (SST k-ω and Realizable k-ε) and four unsteady turbulence models (URANS SST k-ω and Realizable k-ε, SST-SAS, and SST-IDDES) are evaluated with respect to their capacity to predict crosswind characteristics on high-speed trains (HSTs). All of the numerical simulations are compared with the wind tunnel values and LES results to ensure the accuracy of each turbulence model. Specifically, the surface pressure distributions, time-averaged aerodynamic coefficients, flow fields, and computational cost are studied to determine the suitability of different models. Results suggest that the predictions of the pressure distributions and aerodynamic forces obtained from the steady and transient RANS models are almost the same. In particular, both SAS and IDDES exhibits similar predictions with wind tunnel test and LES, therefore, the SAS model is considered an attractive alternative for IDDES or LES in the crosswind study of trains. In addition, if the computational cost needs to be significantly reduced, the RANS SST k-ω model is shown to provide relatively reasonable results for the surface pressures and aerodynamic forces. As a result, the RANS SST k-ω model might be the most appropriate option for the expensive aerodynamic optimizations of trains using machine learning (ML) techniques because it balances solution accuracy and resource consumption.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.27 no.3
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• pp.264-270
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• 2023

Backgrounds/Aims: Proximal splenorenal shunt (PSRS) is a commonly performed procedure to decompress portal hypertension, in patients with refractory variceal bleed, especially in non-cirrhotic portal hypertension (NCPH). If conventional methods are hindered by any technical or pathological factors, alternative surgical techniques may be required. This study analyzes the effectiveness of various unconventional shunt surgeries performed for NCPH. Methods: A retrospective analysis of NCPH patients who underwent unconventional shunt surgeries during the period July 2011 to June 2022 was conducted. All patients were followed up for a minimum of 12 months with doppler study of the shunt to assess shunt patency, and upper gastrointestinal endoscopy to evaluate the regression of varices. Results: During the study period, 130 patients underwent shunt surgery; among these, 31 underwent unconventional shunts (splenoadrenal shunt [SAS], 12; interposition mesocaval shunt [iMCS], 8; interposition PSRS [iPSRS], 6; jejunal vein-cava shunt [JCS], 3; left gastroepiploic-renal shunt [LGERS], 2). The main indications for unconventional shunts were left renal vein aberration (SAS, 8/12), splenic vein narrowing (iMCS, 5/8), portalhypertensive vascular changes (iPSRS, 6/6), and portomesenteric thrombosis (JCS, 3/3). The median fall in portal pressure was more in SAS (12.1 mm Hg), and operative time more in JCS, 8.4 hours (range, 5-9 hours). During a median follow-up of 36 months (6-54 months), shunt thrombosis had been reported in all cases of LGERS, and less in SAS (3/12). Variceal regression rate was high in SAS, and least in LGERS. Hypersplenism had reversed in all patients, and 6/31 patients had a recurrent bleed. Conclusions: Unconventional shunt surgery is effective in patients unsuited for other shunts, especially PSRS, and it achieves the desired effects in a significant proportion of patients.

• Journal of the Korean Data and Information Science Society
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• v.8 no.2
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• pp.247-260
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• 1997

The quasi-likelihood models which greatly widened the scope of generalized linear models are widely used in data analysis where a likelihood is not available. Since a quasi-likelihood may not appear to be an ordinary likelihood for any known distribution in the natural exponential family, to fit the quasi-likelihood models the standard statistical packages such as GLIM, GENSTAT, S-PLUS and so on may not directly applied. SAS/IML is very useful for fitting of such models. In this paper, we present simple SAS/IML(version 6.11) program which helps to fit and analyze the quasi-likelihood models applied to the leaf-blotch data introduced by Wedderburn(1974), and the problem with deviance useful generally to model checking is pointed out, and then its solution method is mention through the data analysis based on this quasi-likelihood models checking.

• Journal of Korean Society for Quality Management
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• v.26 no.3
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• pp.130-140
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• 1998

Studies present a guide to parameter estimation of software reliability models using SAS JMP. In this paper, we consider only software reliability growth model(SRGM), where mean value function has a S-shaped growth curve, such as Yamada et al. model, and ohba inflection model. Besides these stochastic SRGM, deterministic SRGM's, by fitting Logistic and Gompertz growth curve, have been widely used to estimate the error content of software systems. Introductions or guide lines of JMP are concerned. Estimation of parameters of Yamada et al. model and Logistic model is accomplished by using JMP. The differences between Yamada et al. model and Logistic model is accomplished by using JMP. The differences between Yamada et al. model and Logistic model is discussed, along with the variability in the estimates or error sum of squares. This paper have shown that JMP can be an effective tool I these research.

• Communications for Statistical Applications and Methods
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• v.8 no.2
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• pp.507-514
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• 2001

In recent years, the development and the embodiment of information analysis system has been sprightly carried out in several fields of study. In this study, as and extension of these studies, we develop a system for multivariate analysis which might be widely used in social and natural sciences. This multivariate analysis system is developed by using multivariate analysis procedures in SAS/STAT software. Also, the system supply users with he environment of GUI(Graphical User Interface), which is constructed with AF(application frame) and SCL(screen control language) of SAS software, in order to help users to use the system with easy.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.802-805
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• 2003

Structural surface becomes an antenna. The integration of antennas into structural body panels is a new high payoff technology. It emerged from the need to improve structural efficiency and antenna performance. In this paper, we developed new design concept for the structural surface which transmits and receives the electromagnetic signals, and it is termed Surface-Antenna-Structure (SAS). Design procedure was presented including structure design. material selection and design of antenna elements, which was processed according to the communication with KORSAT satellite at Ku-Band (12.25-12.75 GHz). The final demonstration article was 350$\times$200$\times$7.5mm flat antenna panel. Experimental results for antenna performances were in good agreements with design requirements. Also structural analysis was performed with SAS. estimating stress distributions under simply supported condition with Laminated Plate Theories and Wavier Solutions. The SAS concept can be extended to give a useful guide to manufacturers of structural body panels as well as antenna designers. promising innovative future communication technology.

• Sleep Medicine and Psychophysiology
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• v.4 no.2
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• pp.140-146
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• 1997

Sleep-related breathing disorders, especially sleep apnea syndrome are complicated by neuropsychiatric dysfunction such as excessive daytime sleepiness, cognitive dysfunction, and depression. As the determinants of daytime sleepiness, sleep fragmentation is more influential than nocturnal hypoxia. Daytime sleepiness can be improved by continuous positive airway pressure (CPAP) or surgery in up to 95% of the treated subjects. Both sleepiness and nocturnal hypoxia would cause cognitive dysfunction. While impairments in attention and verbal memory are more related with sleepiness and prominent in mild to moderate sleep apnea syndrome (SAS), impairments in general intellectual function and executive function are more related with nocturnal hypoxia and prominent in severe SAS. Several cognitive deficits related with nocturnal hypoxia may be irreversible despite CPAP or surgical treatments. So, early detection and early appropriate treatment of SAS would prevent sleepiness and cognitive deterioration.