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PC/ASA blends having enhanced interfacial and mechanical properties
김창근,M. S. Kang,J. W. Lee 한국유변학회 2006 Korea-Australia rheology journal Vol.18 No.1
Blend of bisphenol-A polycarbonate (PC) and (acrylonitrile-styrene-acrylic rubber) terpolymer (ASA) having excellent balance in the interfacial properties and mechanical strength was developed for the automobile applications. Since interfacial adhesion between PC and styrne-acrylonitrile copolymer (SAN) matrix of ASA is not strong enough, two different types of compatibilizers, i.e, diblock copolymer composed of tetramethyl polycarbonate (TMPC) and SAN (TMPC-b-SAN) and poly(methyl methacrylate) (PMMA) were examined to improve interfacial adhesion between PC and SAN. TMPC-b-SAN was more effective than PMMA in increasing interfacial adhesion between PC and SAN matrix of ASA (or weld-line strength of PC/ASA blend). When blend composition was fixed, PC/ASA blends exhibited similar mechanical properties except impact strength and weld-line strength. Impact strength of PC/ASA blend at low temperature was influenced by rubber particle size and its morphology. PC/ASA blends containing commercially available PMMA as compatibilizer also exhibited excellent balance in mechanical properties and interfacial adhesion.
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소난포난의 체외발생에 있어서 혈청첨가와 과립막세포 및 난관상피 세포와의 공배양 효과
정광조,정영채,윤종택,김창근 中央大學校 遺傳工學硏究所 1992 遺傳工學硏究論集 Vol.5 No.1
본 연구는 미성숙난포란을 체외성숙 후 체외수정하여 cell block stage를 극복하고 배를 발생시켜 수정란이식에 의하여 송아지를 생산할수 있는 체외수정 체계를 확립하기위하여 도살장에서 도살되는 한우와 홀스타인 소로부터 체취된 난포란을 혈청과 과립막세포와 체외성숙후 정자처리 방법에 따라 체외수정을 실시하여 과립막세포 및 난관상피세포와 체외배양하여 초기배 발생능을 조사한바 다음과 같은 결과를 얻었다. 1.TCM199 성숙배양액에 FCS와 ECS10%만을 첨가하였을 때 난포란의 체외성숙율은 66.6%와 72.7%이었으나 FCS와 ECS10%를 첨가하고 과립막세포와 공배양하였을 때는 81.3%와 84.0%로 체외성숙율이 향상되었다. 2.TCM 성숙배양액에 10% FCS만을 첨가하고 난포란을 체외성숙시킨 후 caffeine 또는 caffeine-heparin 처리된 정자와 체외수정하였을 때 난할율은 19.0%와 18.4%이었다. 또한 FCS10%와 과립막세포와 공배양하여 체외성숙시킨 난포란의 난할율은 25.0%와 22.9%이었다. 3.TCM199성숙배양액에 10% FCS만을 첨가하여 성숙시킨 후 caffeine-heparin 처리된 정자와 체외수정하여 TCM199성숙배양액에 10% FCS만을 첨가하여 체외배양하였을 때 난포란의 발생율은 22.2%이었으나 상실배까지는 발생되지 않았다. 4.10% FCS 및 과립막세포와 공배양하여 체외성숙 시킨 후 체외수정한 다음 난관상피세포와 공배양하여 체외배양하였을 때 배발생율은 46.0%이었고 과립막세포와 체외배양하였을 때는 50.2%이었다. 5.TCM199 성숙배양액에 10% ECS만을 첨가하여 과립막세포와 공배양하여 체외수정한다음 난관상피세포와 공배양하여 체외배양 하였을 때 배발생율은 45.2%이었고 과립막세포와 체외배양하였을 때는 51.4%이었다. 6.TCM199 성숙배양액에 10% FCS및 과립막세포와 체외성숙시킨 난포란을 caffeine처리된 정자와 체외수정하여 난관상피세포와 공배양하여 체외배양하였을 때 배발생율은 38.4%이었다. Caffeine-heparin 처리된 정자와 체외수정하여 난관상피세포와 공배양하여 체외 배양하였을 때 배발생율은 42.6%이었고 과립막세포와 체외배양하였을 때 52.2%이었다. 7.10% ECS 및 과립막세포와 공배양하여 체외성숙시킨 한우 난포란의 배발생율은 난관상피세포와 공배양하여 체외배양하였을 때 41.8%이었고 과립막세포와 체외배양하였을 때는 57.1%이었다. 한편 FCS10% 및 과립막세포와 공배양하여 체외성숙시킨 후 난관상피세포와 공배양하여 체외배양하였을 때 배발생율은 42.0%이었고 과립막세포와 체외배양하였을 때는 48.4%이었다. These studies were carried out to investigate the effects of sera(fetal calf serun: FCS: and estrus cow serum: ECS) and granulosa cells(GC) added to maturation medium for in vitro maturation and developmental capacity of bovine follicular oocytes co-cultured with bovine epithelial cells(BOED) and granulosa cells in vitro. The ovaries were obtained from slaughtered Korean native cows and Holsteines, The follicular oocytes were cultured in TCM199 medium with sera and granulosa cells for 24hrs. The matured oocytes were fertilized in vitro using frozen-thawed sprematozoa in BO solution containing caffeine(5mM/ml) or caffeine(5mM/ml)-heparin(10mg/ml), and then the oocytes were co-cultured with bovine epithelial cells or granulosa cells. The results obtained were summarized as follows: 1.In vitro maturation rates of bovine follicular oocytes cultured in TCM199 with 10% FCS or ECS were 66.6% and 72.2%, but the case of addition of 10% FCS or ECS to TCM199 co-cultured with granulosa cells were 81.3% and 84.0%, respectively. IVM rate of these TCM199 added to granulosa cells was higher than that of media without granulosa cells. 2.Cleavage rates of follicular oocytes matured in TCM199 with 10% FCS alone and then fertilized in vitro by sperm treated with caffeine or caffeine-heparin were 19.0% and 18.4%, but the case of addition of 10% FCS to TCM199 with granulosa cells were 25.0% and 22.9%. 3.Cleavage rates of bovine oocytes cultured with 10% alone and fertilized in vitro by sperm treated with caffeine-heparin was 22.2%, but there was no blastocyst. 4.When bovine follicular oocytes were matured in TCM199 with 10% FCS and GC, embryo developments of bovine oocytes co-cultured with BOEC of GC were 46.0% and 50.2%, respectively. 5.When bovine follicular oocytes were matured in TCM199 with 10% ECS and GC, embryo developments co-cultured with BOEC or GC were 45.2% and 51.4%, respectively. 6.When bovine follicular oocytes were matured in TCM199 with 10% FCS and GC and then fertilized in vitro by sperm treated with caffeine, embryo developments of bovine oocytes co-cultured with BOEC were 38.4% and 51.4%, respectively. But those of bovine oocytes co-cultured with GC were 52.2% by sperm treated with caffeine-heparin. 7.When Korean native cow's follicular oocytes matured in TCM199 with 10% FCS and GC, embryo developments of the bovine oocytes co-cultured with BOEC and GC were 41.8% and 57.1%. But with FCS 10% those of the bovine oocytes co-cultured with BOEC and GC were 42.0% and 48.4%, respectively. 8.When Holsteine's follicular oocytes were matured in TCM199 with 10% ECS and GC, embryo developments of the bovine oocytes co-cultured with BOEC and GC were 50.0% and 56.9%, but with ECS 10% those of the bovine oocytes co-cultured with BOEC and GC were 52.2% and 56.5%, respectively. 9.The Present results indicate that sera and GC added to TCM199 are the effective components for in vitro maturation of bovine oocytes and for in vitro development, developmental capacity of bovine oocytes is improved when they are co-cultured with the somatic cells such as BOEC and GC.
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박규석,김창근 慶南大學校 附設 工業技術硏究所 1998 硏究論文集 Vol.15 No.3
최근 가상학교에서는 효과적인 실시간 평가시스템을 이용한 피드백식 반복 학습 방식이 주요한 과제가 되고 있다. 본 연구에서는 가상학교에서 적절한 온라인 평가시스템을 구현하였다. 이 시스템은 학생들이 학습과정에서 즉각적인 피드백으로 자기 자신의 평가와 성취도를 파악할 수 있게 하고, 교수는 시험 및 평가에 관련된 과중한 업무를 줄일 수 있도록 한다. Recently a repeated study with an instant feedback through the efficient real-time evaluating system has been a critical issue in the distance learning and self-paced instruction In this paper, we design and implement the online evaluating system, which is applicable appropriately to such as the instruction system, allows the students to understand their accomplishment through the self-evaluating and the instructors to diminish an heavy workload on testing and evaluating the achievements of students by supporting the instant feedback on self-learning.
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