• Membrane Journal
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• v.20 no.4
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• pp.320-325
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• 2010

This paper was carried out to study the preparation condition and the permeation flux of reinforced poly(vinylidene fluoride) (PVDF) hollow fiber microfiltration (MF) membrane with the solvent, additive, second miscible polymer, and preparation condition used poly(vinylidene fluoride) (PVDF) such as a material with the excellent chemical stability and the milder preparation condition. The performance of the reinforced MF membrane prepared obtained the average $0.3{\mu}m$ pore size, $42kg_f/cm^2$ tensile strength, and the high water flux of 600 LMH. The change of membrane performance with various additives was considerably affected on the water flux and rejection. For hydrophilic modification of hydrophobic PVDF MF membrane, the MF membrane might be prepared with a prefer water flux and rejection by addition of hydrophilic poly(methyl methacrylate) (PMMA).

• Fashion & Textile Research Journal
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• v.25 no.4
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• pp.460-471
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• 2023

This study aimed to analyze the consumption value and clothing pursuit benefits of genderless fashion based on gender identity. The study questionnaire was distributed to and collected from men and women in their 20s and 30s living in Seoul City and the Gyeonggi province. The collected data were analyzed by using Cronbachs α, factor analysis, K-means group classification analysis, and ANOVA. The study results were as follows. First, gender identity was categorized into three groups: the genderless group, the traditional gender rejection group, and the traditional gender acceptance group. Therefore, it is necessary to subdivide gender identity rather than acceptance and rejection of traditional gender roles. Second, an analysis of consumption value based on gender identity showed significant differences in terms of fashion value and expressive value. Therefore, it is important to establish a differentiated strategy based on the relevant gender identity group when establishing genderless fashion design or marketing strategy. Finally, the study results showed that clothing pursuit benefits based on gender identity, there was a significant difference in terms of individuality pursuit, deviation from the norm, and fashion pursuit. In particular, since the genderless phenomenon agrees with the characteristics of the MZ generation, it will be necessary to share brand information or product information through digital media or to utilize a sharing culture-that is, 'meaning out' tendency and 'flex culture' (i.e., conspicuous consumption).

• Membrane Journal
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• v.23 no.1
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• pp.92-99
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• 2013

In this study the nanofiltration (NF) membrane treatment of a sulfuric acid waste solutions containing copper ion ($Cu^{+2}$) discharging from the etching processes of the printed circuit board (PCB) manufacturing industry has been studied for the recycling of acid etching solution. SelRO MPS-34 4040 NF membrane from Koch company was tested to obtain the basic NF data for recycling of etching solution and separation efficiency (total rejection) of copper ion. NF experiments were carried out with a dead-end membrane filtration laboratory system. The pure water flux was increased with the increasing storage time in sulfuric acid solution and lowering pH of acid solution because of the enhancement of NF membrane damage by sulfuric acid. The permeate flux of acid solution was decreased with the increasing copper ion concentration. Total rejection of copper ion was decreased with the increasing storage time in sulfuric acid solution and copper ion concentration, and lowering the pH of acid solution. The total rejection of copper ion was decreased from initial 37% to 15% minimum value.

• Journal of Chest Surgery
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• v.42 no.2
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• pp.135-140
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• 2009

Background: Chronic rejection after a cardiac allograft usually occurs about six months after the operation. Vasculopathy due to chronic rejection causes atherosclerosis in the coronary artery of the transplanted heart and then this causes myocardial injury. We intended to discover and document those findings that occur in a transplanted ascending aorta. Material and Method: In rats weighting $200{\sim}300gm$ (Spraque-Dawley rat), we carried out heterotopic heart allo-transplantation with the modified Ono-Lindsey method and then the rats were administrated cyclosporine (10mg/kg/day). After three months survival, we acquired biopsy materials from the native ascending aorta and the allo-transplanted ascending aorta and we compared them. We classified each severity of 1) intimal thickening, 2) medial hyperplasia, 3) medial calcification, 4) medial inflammation and 5) chondroid metaplasia, which are specific biopsy findings for chronic rejection after a cardiac allograft. Each severity was classified, according to the opinion of one pathologist, in the native ascending aorta biopsies (n=9) and the allo-transplanted ascending aorta biopsies (n=13). The data of the control group and the study group were statistically analyzed with using the Mann-Whitney test (SPSS version 12.0 window). Result: The important changes of the allo-transplanted aorta were intimal thickening (p<0.0001), medial calcification (p=0.045), medial inflammation (p<0.0001) and chondroid metaplasia (p=0.045), but not medial hyperplasia (p=0.36). Conclusion: Cardiac allograft vasculopathy was seen in the transplanted ascending aorta, the same as was seen in the coronary artery, after allograft cardiac transplantation. We have reached the conclusion that chronic rejection also progresses in the aorta.

• Membrane Journal
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• v.5 no.4
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• pp.137-144
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• 1995

This studies concern the separation of aqueous boric acid solution and same solution containing silica using cellulose acetate RO S/W 4040 module manufactured by Hydranautics Co. The operating conditions of the applied pressures, temperatures, and feed flow rate are also investigated to characterize the permeabilities, biroc acid recovery, and silica rejection, so that the optimum operating conditions would be found out. In the case where the operating conditions are the temperature 35$^{\circ}$C, The pressure 20atm, and the feed flow rate 2.82 l/min, for the boric acid aqueous solution, the boric acid recovery 58.7% and the permeation rate 2.82 l/min were obtained. And also the results showed the boric acid recovery 68.1% and the permeation rate 1.56 l/min at the operating conditions, 35$^{\circ}$C and 10atm. For the boric acid solution containing silica, when the feed solution are at the conditions of 35$^{\circ}$C and 3.2atm, the boric acid recovery 69.7%, the silica rejection 97.5% and the permeation rate 0.47 l/min were obtained. And the operating conditions were at 35$^{\circ}$C, 20atm and the feed flow rate 2.92 l/min, the results showed the boric acid recovery 56.4%, the silica rejection 96.1% and the permeation rate 2.72 l/min.

• Korea Trade Review
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• v.48 no.3
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• pp.131-150
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• 2023

The purpose of this study was to find a countermeasure to the U.S. import refusals for the Korean healthcare and life sciences industry. To this end, an analysis of trends during the pandemic was conducted using the KITA Border Rejection Database, which includes information on items and types of import refusals. The reason for rejection was also analyzed according to the FDA violation codes. The degree of countermeasure for import refusals was identified by measuring the unit rejection rate (URR). The results of the analysis showed that the major U.S. import refusals for the Korean healthcare and life sciences industry had expanded from contact lenses to COVID-19 diagnostic kits and drugs after the pandemic broke out. The major reasons for import refusals were non-compliance with the Predicate Device and Drugs Act and non-approval by the FDA for products and facilities. On the other hand, the unit rejection rate (URR) of major items in the Korean healthcare and life sciences industry was measured higher than the industry average. The results therefore showed a low level of response to U.S. import refusals. The results of the analysis of reasons for import refusals by item according to FDA violation codes were as follows. First of all, the main violation for contact lenses and COVID-19 diagnostic kits corresponded to misbranding. This was often due to the fact that Korean companies did not provide the relevant notices and information required by the FDA. Many cases also failed to demonstrate a substantial equivalency compared to predicate devices already on the market. On the other hand, applications for new unapproved drugs were not accepted as they had yet to pass relevant regulations that would prove their safety and efficacy. In conclusion, import refusals for the Korean healthcare and life sciences industry were found to be closely related to technical barriers to trade (TBT).

• Journal of The Korean Association For Science Education
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• v.20 no.2
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• pp.221-233
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• 2000

Many investigators have reported difficulties in changing the high school students' misconceptions on mechanics. By one possible solution to this problem, some researchers suggested that the students should be taught mechanics at a younger age to make conceptual changes possible. because as they get older they become less willing to change their ideas. The purpose of this study was to compare the patterns of students' conceptual changes on force by age, to find out whether older students were less ready to change their conceptions than younger students. Individual interviews were carried out with 35 students (average ages 13) in middle school class and 50 students (average ages 17) in high school class near by the middle school. Those students who held the misconcetpion that "motion-implies-force (Impetus conception)" were asked to read a student-centered refutational text (anomalous data). In the immediate and delayed posttest, the types of responses of the students were analyzed to find out the patterns of student's conceptual changes on force by age. In result, first, most of students had impetus conception. Some of the students aged 13 understood the force as terminologies related with everyday experiences, while the students aged 17 understood the force as scientific terminologies. Second, there was no evidence to suggest that conceptual change is more difficult for the students aged 17 than aged 13. Third, the students aged 13 showed diverse responses (plain acceptance, critical acceptance, plain rejection, critical rejection) to the refutational text, while the students aged 17 showed restricted responses (critical acceptance, critical rejection). A month later those students who showed the plain acceptance retrogressed unscientific conceptions, while those students who showed critical acceptance maintained scientific conceptions. We did not find out any evidence to suggest that conceptual change is more difficult for older students. These results need deeper investigation on the nature of the loss of plasticity in comparison with other important variables.

• Journal of the Korean Institute of Intelligent Systems
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• v.5 no.1
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• pp.25-32
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• 1995

In this paper, the FLVSC (Fuzzy Logic Variable Structure controller), of which control rules are extracted from the concepts of the VSC(Variable Structure control) is proposed and diesgned for drum motor(BLDC motor) in home VCR. The FLC (Fuzzy Logic Controller) based on linguistic rules has the advantages of not needing of some exact mathermatical model for plant to be controlled. The proposed method has the characteristics which are viewed in conventional VSC, e.g. insensitivity to a class of distrubances, parameter variations and uncertainites in a sliding mode. In addition, the method has the properties of the FLC-noise rejection capability etc. The computer simulation and experiment using DSP(TMS320C30) have been carried out for the servo control of VCR drum motor to show the usefulness of the proposed method.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.5
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• pp.809-818
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• 1994

In this paper , the author proposed FLVSC (Fuzzy Logic Variable Structure Controller),of which control rules are extracted from the concepts of VSC(Variable Structure Control). FLC(Fuzzy Logic Controller) based on linguistic rules has the advantages of not needing of some exact mathematical model for plant to be controlled. The proposed method has the characteristics which are viewed in conventional VSC, e.g. insensitivity to a class of disturbances, parameter variations and uncertainties in sliding mode. In addition, the method has the properties of FLC-noise rejection capability etc. The computer simulations have been carried out for position control of DC servo motor to show the usefulness of the proposed method and the effects of disturbances and parameter variations are considered.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.285-285
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• 1996

Cyclosporin A (CyA) is widely used in the inhibition of graft rejection in organ transplantation. However, the bioavailability of CyA after oral administration is very low due to its poor solubility and dispersability hi water. To improve the solubility of CyA, microemulsion systems were developed and its physicochemical characteristics were evaluated by phase studies, solubility and dispersability tests. Phase studies on the systems composed of ethyl oleate (EO), PPG-20 methyl glucose ether (GP-20), poloxamer 123 (PL) and water U) were carried out to make stable w/o emulsions. Besides, based on CyA solubility test in various compositions of surfactant systems, a reasonable surfactant composition (GP-20/PL=4/1) was selected to enhance its solubility.