http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Ja Hun Kwak (검색결과 34 건)
- 무료
- 기관 내 무료
- 유료
-
곽준식,김순자,김훈희 진주산업대학교 산업과학기술연구소 1994 산업과학기술연구소보 Vol.- No.1
The purpose of this study is to present the directions on the educational contents and activities in various vocational education through reviewing the historical development in them and the current research in each of the various vocational education. The process of this study is made in order of the follws ; 1) reviewing the educational contents and activities in various vocational education from the early 20th century up to now, 2) classifying and arranging the contents and activities of vocational education, based on theses reviewed materials, and 3) presenting the specific taske to solve in various vocational education and concluding this study, based on these classified and arranged materials. The classification of vocational education is based in the subfields of vocational education which Copa and Bently classified. The subfields are agritultural education, business edutation, home economics education, industirial education, business education, marketing education, health occupations education, career education and vocational education. In conclusion, the future of the curricular research in vocational education should be done as follows , 1) broader and more expansive consideration of educational excellence, 2) specific review of various vocational education from several different conceptual and philosophical perspectives, and 3) research in the relation between theory and practice of vocational education. And, the content and activities of vocational education should focus not only on meeting the needs of rapidly changing society but on making possible to accept the culture of society, to help individuals prepare their career and to improve their own life.
-
-
Ju Hun LEE,Do Yoon LEE,Hyeong Ryeol KIM,Kyung Rae KIM,Eun Jeong KIM,Chulhwan PARK,Hah Young YOO,Ho Seok KWAK,Seung Wook KIM,Ja Hyun LEE 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
In this study, extracted sugars of microalgae, which cause algal blooms and crude glycerol, which is a biodiesel industry by-product, were used simultaneously to produce 2,3-BDO. The 2,3-BDO production using only extracted algal sugars was about 4.8 g/L at 18 h, and the production of 2,3-BDO using both extracted algal sugar and crude glycerol was about 7 g/L at 18 h. It was confirmed that the main culture with crude glycerol was increased 1.5-fold compared to the case of using only extracted algal sugars. In addition, four components of the main medium (ammonium sulfate, casein hydrolysate, yeast extract and crude glycerol) were statistically optimized and the concentrations of the medium were 12 g/L, 16 g/L, 12 g/L and 13 g/L, respectively. In addition, the final 2,3-BDO production was about 11g/L, which 1.6-fold higher than before optimization process. As a result, it has been confirmed that 2,3-BDO production is possible through the simultaneous use of algal sugars and crude glycerol, which can greatly contribute to the development of zero-waste processes.
-
Evidence of <i>Toxoplasma gondii</i> Exposure among Horses in Korea
LEE, Seung-Hun,LEE, Sang-Eun,SEO, Min-Goo,GOO, Youn-Kyoung,CHO, Kwang-Hyun,CHO, Gil-Jae,KWON, Oh-Deog,KWAK, Dongmi,LEE, Won-Ja The Japanese Society of Veterinary Science 2014 The Journal of veterinary medical science Vol.76 No.12
<P>The present study investigated the seroprevalence of <I>Toxoplasma gondii </I>(<I>T. gondii</I>) antibodies by ELISA in horses reared in Korea. Serum samples were collected from 2009 through 2013 from 816 horses reared in Korea. Analysis was performed using a commercial toxoplasmosis ELISA kit to detect anti-<I>T. gondii</I> antibodies. Overall, 24 out of 816 horses (2.9%) were seropositive for <I>T. gondii</I>. The result was analyzed by age, gender, breed and region. Significant differences were observed according to breed and region (<I>P</I><0.05). This is the first nationwide serological investigation of <I>T. gondii</I> in horses reared in Korea. The study results reveal that <I>T. gondii</I> occurs nationwide in Korean horses.</P>
-
Szanyi, Já,nos,Kwak, Ja Hun The Royal Society of Chemistry 2014 Physical chemistry chemical physics Vol.16 No.29
<P>Alumina supported Pd catalysts with metal loadings of 0.5, 2.5 and 10 wt% were investigated by <I>in situ</I> FTIR spectroscopy in order to understand the nature of adsorbed species formed during their exposure to CO<SUB>2</SUB> and CO. Exposing the annealed samples to CO<SUB>2</SUB> at 295 K resulted in the formation of alumina support-bound surface species only: linear adsorbed CO<SUB>2</SUB>, bidentate carbonates and bicarbonates. Room temperature exposure of all three samples to CO produced IR features characteristic of both ionic and metallic Pd, as well as bands we observed upon CO<SUB>2</SUB> adsorption (alumina support-bound species). Low temperature (100 K) adsorption of CO on the three samples provided information about the state of Pd after oxidation and reduction. Oxidized samples contained exclusively ionic Pd, while mostly metallic Pd was present in the reduced samples. Subsequent annealing of the CO-saturated samples revealed the facile (low temperature) reduction of PdO<SUB><I>x</I></SUB> species by adsorbed CO. This process was evidenced by the variations in IR bands characteristic of ionic and metallic Pd-bound CO, as well as by the appearance of IR bands associated with CO<SUB>2</SUB> adsorption as a function of annealing temperature. Samples containing oxidized Pd species (oxidized, annealed or reduced) always produced CO<SUB>2</SUB> upon their exposure to CO, while no CO<SUB>2</SUB>-related surface entities were observed on samples having only fully reduced (metallic) Pd.</P> <P>Graphic Abstract</P><P>Surface species formed on Pd/γ-Al<SUB>2</SUB>O<SUB>3</SUB> upon CO<SUB><I>x</I></SUB> exposure will aid mechanistic studies of CO<SUB>2</SUB> reduction. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4cp00617h'> </P>
-
Won-Hong Woo,Seong-Hun Ahn,Yeun-Ja Mun,Sung-Won Lee,Sup Kwak,Min-Kyu Choi,Soon-Ki Baik,Yeong-Mok Kim 한국식품영양과학회 2006 Journal of medicinal food Vol.9 No.2
Cell apoptosis is now known to play an important role in the maintenance of cellular homeostasis and anti-carcinogenesis. Selaginella tamariscina(ST) is a traditional medicinal plant for treatment of advanced cancer in the Orient.In the present study, the anticancer effect of ST was investigated by analyzing its potential to induce apoptosis in humanleukemia HL-60 cells. ST-induced cytotoxicity of HL-60 cells was monitored by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay. The apoptosis was determined by microscopic examination of apoptotic morphology, determina-tion of DNA fragmentation by electrophoresis, activation of caspase-3, and protein expression of procaspase-3, poly(ADP-ri-bose) polymerase (PARP) cleavage, Bcl-2, and Bax. ST was cytotoxic to HL-60 cells in a dose-dependent manner. However,ST-induced cytotoxicity was suppressed by reactive oxygen species scavengers, including superoxide dismutase (SOD) andcatalase. ST caused DNA fragmentation and nuclear condensation, all characteristics of apoptosis. ST-induced apoptosis isaccompanied by the activation of caspase-3 and the specific proteolytic cleavage of PARP. Concomitantly, ST treatments ledto an increase in the proapoptotic Bax levels, while Bcl-2 expression was decreased. Moreover, this effect was attenuated bySOD and catalase. These results suggest that oxidative stress may be involved in the cytotoxicity of ST, and that ST-inducedapoptosis of HL-60 cells is primarily mediated by the caspase activation pathway.
-
Szanyi, Já,nos,Kwak, Ja Hun The Royal Society of Chemistry 2014 Physical chemistry chemical physics Vol.16 No.29
<P>The adsorption of CO<SUB>2</SUB> and CO was investigated on a pure γ-Al<SUB>2</SUB>O<SUB>3</SUB> support material that has been used in Pd and Ru catalysts for the reduction of CO<SUB>2</SUB>. The adsorption of CO<SUB>2</SUB> resulted in the formation of carbonates, bicarbonates and linearly adsorbed CO<SUB>2</SUB> species. The amount and the nature of the adsorbed species were dependent on the annealing temperature of the alumina support. On γ-Al<SUB>2</SUB>O<SUB>3</SUB> annealed at 473 K mostly bicarbonates formed, while no adsorbed CO<SUB>2</SUB> was seen on this highly hydroxylated surface. With increasing calcination temperature the amount of both surface carbonates and linearly adsorbed CO<SUB>2</SUB> increased, but still the most abundant surface species were bicarbonates. Surface carbonates and adsorbed CO<SUB>2</SUB> can readily be removed from the alumina surface, while bicarbonates are stable to elevated temperatures. The interaction of CO with γ-Al<SUB>2</SUB>O<SUB>3</SUB> is much weaker than that of CO<SUB>2</SUB>. At room temperature CO adsorbs only on Lewis acid sites, and can be readily removed by evacuation. At 100 K CO can probe different defect sites on the alumina surface. Under no conditions we have observed the formation of any carbonates or bicarbonates upon the interaction of CO with the pure alumina support. In co-adsorption experiments CO competes for adsorption sites with the linearly adsorbed CO<SUB>2</SUB> on the 773 K-annealed γ-Al<SUB>2</SUB>O<SUB>3</SUB> surface, but it does not result in the desorption of CO<SUB>2</SUB>, rather in the increased production of weakly held carbonates. After the removal of adsorbed CO, CO<SUB>2</SUB> moves back to its original adsorption sites, <I>i.e.</I>, Lewis acidic Al<SUP>3+</SUP> centers. The exposure of a CO<SUB>2</SUB>-saturated γ-Al<SUB>2</SUB>O<SUB>3</SUB> to H<SUB>2</SUB>O did not affect any of the adsorbed surface species. The findings of this study will be used to rationalize the results of our ongoing <I>in situ</I> and <I>in operando</I> studies on the reduction of CO<SUB>2</SUB> on supported Pd and Ru catalysts.</P> <P>Graphic Abstract</P><P>The adsorption of CO<SUB>2</SUB> on γ-Al<SUB>2</SUB>O<SUB>3</SUB> produces calcination temperature-dependent surface species. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4cp00616j'> </P>
-
-
-
Mesoporous mixed CuCo oxides as robust catalysts for liquid-phase furfural hydrogenation
Nguyen-Huy, Chinh,Lee, Hojeong,Lee, Jihyeon,Kwak, Ja Hun,An, Kwangjin Elsevier 2019 Applied Catalysis A Vol.571 No.-
<P><B>Abstract</B></P> <P>A series of highly ordered mesoporous CuCo oxide catalysts with a controlled composition are successfully synthesized by nanocasting from mesoporous silica, KIT-6 template. Liquid-phase furfural (FAL) hydrogenation is carried out to find the optimal composition of the CuCo oxide catalysts to achieve the best catalytic performance. As-prepared mesoporous mixed CuCo oxides exhibit a high surface area (60‒135 m<SUP>2</SUP> g<SUP>−1</SUP>) and a well-defined ordered mesostructure with homogenous dispersion of Cu and Co. Among various compositions of Cu<SUB>x</SUB>Co<SUB>y</SUB> oxides (<I>x</I> = 1–9) studied, the Cu<SUB>1</SUB>Co<SUB>5</SUB> oxide catalyst shows the highest conversion in the hydrogenation of FAL, which is superior to those achieved with mesoporous monometallic oxides, CuO and Co<SUB>3</SUB>O<SUB>4</SUB>. While 2-methylfuran is produced from furfuryl alcohol via <I>aldehyde hydrogenation</I> and subsequent <I>hydrogenolysis</I>, the formation of 2-methylfuran increased with a decrease in the Cu/Co ratio of the CuCo oxide catalyst. The mixed CuCo oxide catalyst is readily reduced under the reaction environment to produce metallic CuCo as the active species. The synergistic interactions between Cu and Co in the mixed CuCo oxide catalysts play an important role in the outstanding catalytic performance for FAL hydrogenation, which could not be achieved with either of the monometallic catalysts or their physical mixtures. The excellent stability and recyclability of mesoporous mixed CuCo oxide catalysts as well as the exceptionally high activity, surpassing those of the monometallic oxides, render them promising as a low-cost and efficient catalyst for the industrial upgrading of biomass-derived FAL.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mixed CuCo oxides exhibit a high surface area and ordered mesostructure. </LI> <LI> Cu<SUB>1</SUB>Co<SUB>5</SUB> catalyst shows the highest conversion in furfural hydrogenation. </LI> <LI> 2-methylfuran yield increases with a decrease in the Cu/Co ratio. </LI> <LI> The catalyst is in-situ reduced to produce metallic CuCo as the active species. </LI> <LI> Cu<SUB>1</SUB>Co<SUB>5</SUB> oxides are low-cost efficient catalysts for upgrading of biomass-derived furfural. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
