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PSf-co-PPSS/HPA를 이용한 수소제조 수전해용 고체 고분자 전해질 복합 막의 제조
정윤교,황갑진,배기광,심규성,강안수,이혁재,장인영 한국수소및신에너지학회 2005 한국수소 및 신에너지학회논문집 Vol.16 No.2
Proton conducting solid polymer electrolyte (SPE) membranes have been used in many energy technological applications such as water electolysis, fuel cells, redox-flow battery, and other electrochemical devices. The availability of stable membranes with good electrochemical characteristics as proton conductivity at high temperatures above 80 and low cost are very important for its applications. However, the presently available perfluorinated ionomers are not applicable because of high manufacturing cost and high temperature use to the decrease in the proton conductivity and mechanical strength. In order to make up for the weak points, the block copolymer (BPSf) of polysulfone and poly (phenylene sulfide sulfone) were synthesized and sulfonated. The electrolyte membranes were prepared with phosphotungstic acid (HPA)/sulfonated BPSf via solution blending. This study would be desirable to investigate the interaction between the HPA and sulfonated polysulfone. The results showed that the characteristics of SPSf/HPA blend membrane was a better than Nafion at high temperature, 100 . These membranes proved to have a high proton conductivity, 6.29 10-2 S/cm, a water content, 23.9 %, and a ion exchange capacity, 1.97 meq./g dry membrane. Moreover, some of the membranes kept their high thermal and mechanical stability.
정윤교 國立 昌原大學校 産業技術硏究所 1994 産技硏論文集 Vol.8 No.-
The application of advanced ceramics as a substitute for classical is increasing because of their excellent properties. It is, however, not easy to grind these materials because they are strong, hard and brittle. In this study, representative advanced ceramics are ground and grinding mechanism is discussed in terms of the grinding force, grinding energy and surface roughness. The depth of the residual crack after grinding and critical grain load is estimated on the basis of the indentation theory. Furthermore, the propriety for results obtained is investigated by observation of a grinding profile.
청소년의 수면 문제가 내재화 및 외현화 문제행동에 미치는 영향과 정서조절곤란의 매개효과
정윤교,박미연,이지혜,김현경,주수산나 한국심리학회 산하 한국발달심리학회 2023 한국심리학회지 발달 Vol.36 No.3
This study examined the extent to which sleep problems influenced internalizing and externalizing problems directly or indirectly through emotion dysregulation among adolescents. The sample comprised 5,454 adolescents (2,586 girls, 10-14 years old) drawn from the 4th wave of the Adolescent Brain Cognitive Development Study (ABCD study 2019-2021) conducted by the National Institutes of Health (NIH). The findings of path analysis indicated that higher levels of sleep problems were significantly and positively associated with emotion dysregulation, internalizing, and externalizing problems. In addition, higher levels of emotion dysregulation significantly mediated the effects of sleep problems on internalizing and externalizing problems. The findings indicate that addressing sleep problems and improving emotion regulation skills can be effective ways for preventing internalizing and externalizing problems among adolescents who are vulnerable to sleep issues.
정윤교,조종래,윤상대,김남경 한국공작기계학회 2004 한국공작기계학회 추계학술대회논문집 Vol.2004 No.-
This polishing machine has many advantages to polish complicated shaped molds due to spindle header with constant pressure. But, because of new polishing machine, there is no study of the standardization of polishing by polishing conditions yet. So we want to know the relation between polishing conditions(a kind of tool, grain size) and surface roughness. The result of experimental was obtained surface roughness of 0.061㎛ Ry in case of using wood tool and grain of 6㎛ diamond.
정윤교 國立 昌原大學校 産業技術硏究所 1990 産技硏論文集 Vol.4 No.-
Advanced ceramics have some excellent properties which are suitable for mechanical components. It is, however, quite difficult to grind ceramics with high efficiency because of their high strength, hardness and brittleness, Now, creep-feed grinding is well known as an effective technology to increase the productivity of form grinding. In this study, creep-feed grinding is carried out for representative advanced ceramics, such as Al₂O₃, SiC, and Si₃N₄. The grinding force, surface roughness, chipping size and grinding rato are experimentally investigated. In addition, some proposals are made to resolve adverse effects in creep-feed grinding. Experimental results show that a resinoid bonded diamond wheel with grooves on the grinding surface. which is proposed in this study, has an excellent performance. Furthermore. the influence of the grinding fluid on the creep-feed grinding is investigated.