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        A novel chimeric promoter that is highly responsive to hypoxia and metals

        Lee, J-Y,Lee, Y-S,Kim, J-M,Kim, K L,Lee, J-S,Jang, H-S,Shin, I-S,Suh, W,Jeon, E-S,Byun, J,Kim, D-K Nature Publishing Group 2006 Gene Therapy Vol.13 No.10

        To develop a potent hypoxia-inducible promoter, we evaluated the usefulness of chimeric combinations of the (Egr-1)-binding site (EBS) from the Egr-1 gene, the metal-response element (MRE) from the metallothionein gene, and the hypoxia-response element (HRE) from the phosphoglycerate kinase 1 gene. In transient transfection assays, combining three copies of HRE (3 × HRE) with either EBS or MRE significantly increased hypoxia responsiveness. When a three-enhancer combination was tested, the EBS–MRE-3 × HRE (E–M–H) gave a hypoxia induction ratio of 69. The expression induced from E–M–H-pGL3 was 2.4-fold higher than that induced from H-pGL3 and even surpassed the expression from a human cytomegalovirus promoter-driven vector. The high inducibility of E–M–H was confirmed by validation studies in different cells and by expressing other cDNAs. Gel shift assays together with functional overexpression studies suggested that increased levels of hypoxia-inducible factor 1α, metal transcription factor-1 and Egr-1 may be associated with the high inducibility of the E–M–H chimeric promoter. E–M–H was also induced by hypoxia mimetics such as Co<SUP>2+</SUP> and deferoxamine (DFX) and by hydrogen peroxide. Gene expression from the E–M–H was reversible as shown by the reduced expression of the transgene upon removal of inducers such as hypoxia and DFX. In vivo evaluation of the E–M–H in ischemic muscle revealed that erythropoietin secretion and luciferase and LacZ expression were significantly higher in the E–M–H group than in a control or H group. With its high induction capacity and versatile means of modulation, this novel chimeric promoter should find wide application in the treatment of ischemic diseases and cancer.Gene Therapy (2006) 13, 857–868. doi:10.1038/sj.gt.3302728; published online 9 February 2006

      • KCI등재

        Effects of Deletion of Supplementary Vitamins and Trace Minerals on Performance, Muscle Vitamin E and Fecal Trace Mineral Contents in Finishing Pigs

        Lee, S. C.,Lee, C. E.,Kim, K. I. 한국동물자원과학회 2003 한국축산학회지 Vol.45 No.4

        비육후기 사료에서 비타민-미량광물질 첨가제의 제거가 돼지의 성장, 사료효율, 혈 중 헤모글로빈 농도, 돈육 내 비타민 E 및 분 중 미량광물질 함량에 미치는 영향을 구명하기 위하여 사육환경이 서로 다른 돈사에서 두 번의 시험이 수행되었다. 시험 1에서는 45두의 비육돈(평균체중 70 ㎏, 3원교잡종)을 돈방 당 5두씩 배치하고, 대조구 (비타민-미량광물질 프리믹스 첨가), 프리믹스 50% 및 0% 첨가구에 각각 3돈방을 배치하여 환기와 온도가 제어되지 않는 재래식 톱밥돈사에서 7주동안 사양한 후 도축하였다. 시험 2에서는 돈사 환기 및 온도가 자동 조절되는 슬러리 무창돈사에서 36두의 요크셔 비육돈 (평균체중 56 ㎏)을 돈방 당 4두씩 배치, 대조구(비타민-미량광물질 프리믹스 첨가), 프리믹스 0% 및 프리믹스 0%+비타민E(100 ㎎ α-tocopherol acetate/㎏) 첨가구에 각각 3돈방을 배치하여 7주 동안 사양 후 도축하였다. 두 시험에서 처리 간 일당증체량, 사료섭취량, 사료효율 및 도체특성은 유의차가 없었으나 시험 2에서는 대조구의 일당증체량이 약간 높은 경향을 보였다. 프리믹스의 미 첨가는 헤모글로빈 함량이나 적혈구 수에 영향을 주지 않았다. 분 중 Mn과 Zn 함량은 대조구에서 프리믹스를 첨가하지 않은 다른 처리에서 보다 매우 높게 (P < 0.01) 나타났다. 혈 중 미량광물질 함량은 처리간 유의차를 보이지 않았다. 햄 근육 (gluteus maxima) 내 α-tocopherol 함량은 프리믹스를 첨가하지 않음으로써 감소하였으나 (P < 0.01), 도살 전 2주 동안 α-tocopheryl acetate(100㎎/㎏ diet)를 급여함으로써 프리믹스 첨가구보다도 더 증가하였다 (P < 0.01). 본 연구결과 돼지 비육후기 사료에 비타민-미량광물질 프리믹스의 첨가는 성장율에는 큰 영향을 미치지 않으면서 분 중 일부 미량광물질을 증가시키기 때문에 경제적인 손실과 토양오염의 위험이 있음을 말해 준다. 프리믹스 제거로 인한 고기 내 비타민 E 함량의 감소는 마지막 2주동안 α-tocopherol를 첨가 급여함으로써 회복될 수 있다. Two experiments were conducted to determine the effects of deletion of vitamin and trace mineral premixes on growth, feed efficiency, backfat thickness, hemoglobin content, muscle vitamin E content, and fecal, serum and fecal, serum and muscle trace mineral contents in finishing pgis raised under two different housing conditions. In Exp. 1. three pens (or experimental units) of five pigs each (average weight ± s.e., 70±0.5㎏) were assigned to a control diet (with vitamin and trace mineral premixes) or diets with 50 or 100% of the premixes deleted. Pigs were fed to market weight under sub-optimal housing conditions with sawdust-covered concrete floor and no electrical ventilation. In Exp. 2. three pens of four pigs each (average weight ± s.c., 56± 1.1㎏) wer assigned to a control (with vitamin and trace mineral premixes), Diet-P (100% of the premixes deleted) or Diet-P+e (Deit-P plus 100㎎ α-tocopherol acetate/㎏ diet fed for the last 2wk before slaughter). Pigs were fed to market weight under optimal housing conditions with 70%-slatted concrete floor, electrical ventilation and temperature control. No significant differences were found in average daily gain (ADG), average daily feed intake IADFI), and gain/feed among treatments in both experiments, but in Exp. 2 done with younger pigs, ADG and ADFI tended to be higher in the control group than in pigs fed diet without premixes. Hemoglobin content, hematocrit and red blood cell count were not influenced by the deletion of premixeds. Backfat thickness was not different among treatments. Fecal Mn (twofold) and Zn (threefold) contents were higher in the control than in pigs fed diets without the premixes. Serum trace mineral contents were not influenced by diets. α-Tocopherol content in gluteus maxima was decreased (p<0.01) by deleting the dietary premixes, but increased to the level higher than the control by adding 100㎎ α-tocopheryl acetate/㎏ diet fed for the last 2 wk before slaughter. Results indicate that :1) supplementary vitamins and trace minerals may not be necessary for optimum growth in finishing pigs, and 2) deletion of the dietary premixes reduces muscle vitamin E content, but the reduced content can be reversed by adding α-tocopherol to diets fed for the last 2 wk before slaughter. The deletion may help to alleviate the environmental load of certain minerals from manure.

      • KCI등재

        철강산업 용융로의 대기오염물질 배출계수 산정 연구

        석광설,방선애,홍지형,이석조,김대곤,이대균,허정숙,이은정 한국대기환경학회 2004 한국대기환경학회지 Vol.20 No.4

        The purpose of this study is 10 estimate of emission factors of the air pollutants for the melting furnaces for the iron and steel industry. The result of this study is able to obtain the emission factor of particulate matters (PM), sulfur dioxide, nitrogen oxides for melting furnace. The emission factors of each pollutants were as follows: - the emission factor varied between 6.13E-03 ∼ 6.12E-01kg/ton for PM - 1.59E-01 ∼ 2.45E+00kg/ton for S0₂ - 6.82E-02 ∼ 6.88E-01kg/ton for NOx, respectively. Analysis of the differences in the emission factors of ours and U.S. EPA's yielded the following results for the Wilcoxon method: p>0.05. The statistical analysis showed no differences in the our emission factors and U.S. EPA's

      • SCISCIESCOPUS

        Interaction of silver(I) and copper(I) with an O<sub>2</sub>S<sub>2</sub>-macrocycle - A comparative structural study

        Kim, S.,Lee, E.,Lee, S.Y.,Lee, S.S.,Lindoy, L.F. Elsevier Sequoia [etc.] 2014 Inorganica chimica acta Vol.417 No.-

        The 14-membered O<SUB>2</SUB>S<SUB>2</SUB>-macrocycle L reacts with AgPF<SUB>6</SUB> in acetonitrile/dichloromethane (1:1) to yield the cyclic, double S-Ag-S bridged complex, [Ag<SUB>2</SUB>L<SUB>2</SUB>(CH<SUB>3</SUB>CN)<SUB>4</SUB>](PF<SUB>6</SUB>)<SUB>2</SUB> (2), in which each Ag(I) is bound to two exo-oriented S donors arising from different macrocycles to form a 12-membered, di-Ag metallacycle. Two PF<SUB>6</SUB><SUP>-</SUP> ions form weak intramolecular contacts [Ag...F, 2.925(2)A] between the Ag centres in a bridging bidentate fashion. The coordination sphere of each Ag is completed by two weakly bound acetonitrile molecules. The respective macrocyclic ligands are arranged trans to the mean plane through the metallacycle. When the above synthetic procedure was repeated employing methanol/dichloromethane (1:1) as solvent, a complex of type [Ag<SUB>2</SUB>L<SUB>2</SUB>](PF<SUB>6</SUB>)<SUB>2</SUB> (3) was obtained whose structure incorporates a similar 12-membered metallacycle but with the respective macrocyclic rings now oriented towards the same side of the metallacyclic plane. The reaction of L with AgCF<SUB>3</SUB>SO<SUB>3</SUB> yields [Ag<SUB>2</SUB>L<SUB>2</SUB>(CF<SUB>3</SUB>SO<SUB>3</SUB>)<SUB>2</SUB>].2CH<SUB>3</SUB>CN (4) whose structure resembles that of [Ag<SUB>2</SUB>L<SUB>2</SUB>(CH<SUB>3</SUB>CN)<SUB>4</SUB>](PF<SUB>6</SUB>)<SUB>2</SUB> (2); each complex unit incorporates a di-Ag(I) 12-membered metallacycle, with symmetrical bridging bidentate CF<SUB>3</SUB>SO<SUB>3</SUB><SUP>-</SUP> ions weakly linking Ag centres. Long Ag1...Ag1C contacts are present between pairs of complex units. Reaction of Cu(CH<SUB>3</SUB>CN)<SUB>4</SUB>PF<SUB>6</SUB> (one equiv.) with L in methanol/dichloromethane (1:1) resulted in isolation of [CuL<SUB>2</SUB>]PF<SUB>6</SUB> (5) incorporating a distorted tetrahedral S<SUB>4</SUB>-coordination sphere, with each macrocycle binding as a bidentate ligand via its two (exo-orientated) S atoms. In contrast, reaction of [Cu(CH<SUB>3</SUB>CN)<SUB>4</SUB>]PF<SUB>6</SUB> (two equiv.) with L in either acetonitrile/dichloromethane (1:1) or methanol/dichloromethane (1:1) yielded [Cu<SUB>2</SUB>L<SUB>3</SUB>]PF<SUB>6</SUB> (6) in which the Cu(I) centres are bound exo to the macrocyclic cavity by individual S-donors from one L, with the coordination sphere of each Cu(I) completed by out-of-plane binding of the S<SUB>2</SUB>O donors from a second L. Unsymmetrical F...Cu contacts from a PF<SUB>6</SUB><SUP>-</SUP> anion weakly link the pair of Cu centres in a bridging bidentate fashion.

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        The E3 ubiquitin ligase CHIP selectively regulates mutant epidermal growth factor receptor by ubiquitination and degradation

        Chung, C.,Yoo, G.,Kim, T.,Lee, D.,Lee, C.S.,Cha, H.R.,Park, Y.H.,Moon, J.Y.,Jung, S.S.,Kim, J.O.,Lee, J.C.,Kim, S.Y.,Park, H.S.,Park, M.,Park, D.I.,Lim, D.S.,Jang, K.W.,Lee, J.E. Academic Press 2016 Biochemical and biophysical research communication Vol.479 No.2

        Somatic mutation in the tyrosine kinase domain of epidermal growth factor receptor (EGFR) is a decisive factor for the therapeutic response to EGFR tyrosine kinase inhibitors (EGFR-TKIs) in lung adenocarcinoma. The stability of mutant EGFR is maintained by various regulators, including heat shock protein 90 (Hsp90). The C terminus of Hsc70-interacting protein (CHIP) is a Hsp70/Hsp90 co-chaperone and exhibits E3 ubiquitin ligase activity. The high-affinity Hsp90-CHIP complex recognizes and selectively regulates their client proteins. CHIP also works with its own E3 ligase activity independently of Hsp70/Hsp90. Here, we investigated the role of CHIP in regulating EGFR in lung adenocarcinoma and also evaluated the specificity of CHIP's effects on mutant EGFR. In HEK 293T cells transfected with either WT EGFR or EGFR mutants, the overexpression of CHIP selectively decreased the expression of certain EGFR mutants (G719S, L747_E749del A750P and L858R) but not WT EGFR. In a pull-down assay, CHIP selectively interacted with EGFR mutants and simultaneously induced their ubiquitination and proteasomal degradation. The expressions of mutant EGFR in PC9 and H1975 were diminished by CHIP, while the expression of WT EGFR in A549 was nearly not affected. In addition, CHIP overexpression inhibited cell proliferation and xenograft's tumor growth of EGFR mutant cell lines, but not WT EGFR cell lines. EGFR mutant specific ubiquitination by CHIP may provide a crucial regulating mechanism for EGFR in lung adenocarcinoma. Our results suggest that CHIP can be novel therapeutic target for overcoming the EGFR TKI resistance.

      • KCI등재

        화력발전소의 대기오염물질 배출계수 산정 연구

        김대곤,엄윤성,홍지형,이석조,석광설,이대균,이은정,방선애 한국대기환경학회 2004 한국대기환경학회지 Vol.20 No.3

        The main purpose of this study was to characterize the air pollutants emission factors in electric power plant (EPP) using fossil fuels. The electric power plant is a major air pollution source, thus knowing the emission characteristics of electric power plant is very important to develop a control strategy. The major air pollutants of concern from EPP stacks are particulate matter (PM), sulfur oxides (SOx), nitrogen oxides (NOx), carbon monoxide (CO) and heavy metals. Throughout the study. the following results arc estimated: - PM : 8.671E-05∼8.724E+01 PM emission (kg) per fuel burned (ton) - SOx: 4.749E-04∼7.877E+01 SOx emission (kg) per fuel burned (ton) - NOx : 1.578E-02∼9.857E+00 NOx emission (kg) per fuel burned (ton) - CO : 3.800E-04∼1.291E+00 CO emission (kg) per fuel burned (ton) - Hg : 1.220E+01∼3.108E+02 Hg emission (mg) per fuel burned (ton) From the statistical analysis by Wilcoxon signed ranks test between the emission factors of ours and U.S. EPA's. we can yielded that: p > 0.05.

      • SCISCIESCOPUS

        Association and functional relevance of E237G, a polymorphism of the high-affinity immunoglobulin E-receptor β chain gene, to airway hyper-responsiveness

        Kim, Y.-K.,Park, H.-W.,Yang, J.-S.,Oh, S.-Y.,Chang, Y.-S.,Shin, E.-S.,Lee, J.-E.,Kim, S.,Gho, Y. S.,Cho, S.-H.,Min, K.-U.,Kim, Y.-Y. Blackwell Scientific Publications 2007 Clinical and experimental allergy Vol.37 No.4

        <P>Summary</P><P>Background</P><P>The hyper-sensitivity reaction of IgE, with its high-affinity receptors (FcϵRI), is central to the phenomenon of atopic diseases.</P><P>Objective</P><P>To evaluate the genetic effects of non-synonymous single-nucleotide polymorphisms (SNPs) of FcϵRI on intermediate phenotypes of asthma, i.e. atopy and airway hyper-responsiveness (AHR), in the Korean general population.</P><P>Subjects and methods</P><P>Atopy and AHR were evaluated in a cohort of 2055 subjects, aged 10–18 years, using skin prick tests (SPTs) for common aeroallergens and total serum IgE and methacholine bronchial provocation tests. All FcϵRI-α, FcϵRI-β, and FcϵRI-γ gene exons of 24 healthy subjects were sequenced to locate informative non-synonymous SNPs (minor allele frequency >2%). Informative SNPs were then scored, using the high-throughput single base extension method. Relative risk (RR) was determined by multiple logistic regression analysis, after adjusting for confounding factors. The functional relevance of non-synonymous SNPs was analysed using the sorting intolerant from tolerant (SIFT) program.</P><P>Results</P><P>The SNP search found only one informative non-synonymous SNP in FcϵRI-β: E237G (minor allele frequency=0.21). The positive rate of AHR was lower among subjects with the 237<SUP>*</SUP>E allele than among those with 237<SUP>*</SUP>G [RR (95% confidence interval)=0.41 (0.19–0.89); <I>P</I>=0.01]. However, the E237G substitution was not associated with either a positive SPT response or total serum IgE levels. Sequence evolution analysis predicted that the E237G variation is an intolerant amino acid substitution, with functional importance.</P><P>Conclusion</P><P>In the Korean general population, AHR is significantly associated with the E237G polymorphism of FcϵRI-β, which results in an intolerant amino acid substitution.</P>

      • protoplast-fusion에 依한 澱粉에서 Ethanol의 單段醱酵能 酵母 開發 : I. Characteristics of two yeast strains and conditions for the protoplast formation and reeneration as a preliminary step in interspecific protoplast-fusion I. Interspecific Protoplast-fusion 을 爲한 酵母菌林의 諸特性과 Protoplast 調製 및 Regeneration 條件

        吳秉夏,黃殷成,李炯周,李啓瑚,朴官和,張海東,徐鉉昌 서울大學校農科大學 1984 서울대농학연구지 Vol.9 No.1

        澱粉으로 부터의 alcohol 醱酵能을 增進시키기 爲하여 澱粉糖化性 菌株인 Saccharomyces diastaticus와 優秀한 alcohol 醱酵性 菌株인 Saccharomyces uvarum을 母菌株로 하여 이들간의 同屬異種間 原形質融合(interspecific protoplast fusion)을 通한 優秀한 澱粉醱酵 性 alcohol 生産性 菌株를 새로이 開發할 目的에서 다음과 같은 一漣의 實驗結果를 얻었다. S. diastaticus의 醱酵液과 S. diastaticus+S. uvarum 混合醱酵液의 風味特性등을 確認하였다. 風味成分 抽出은 methylene chloride와 diethylether를 가지고 neutral flavor fraction과 acidic flavor fraction으로 나누었고 gas chromatography를 通하여 同定 및 定量하였다. Neutral flavor fraction의 경우 S. diastaticus+S. uvarum 混合醱酵液이 S. diastaticus 醱酵液보다, ester成分中에서는 ethyl acetate와 ethyl undecanoate가 더 많았고, alcohol 成分中에서는 n-propanol과 n-butanol이 더 많았다. Acidic flavor fraction의 경우 C??~C?? fatty acid가 同定 및 定量되었는데 S. diastaticus+S. uvarum 混合醱酵液이 S. diastaticus 醱酵液보다 lauric acid, caprylic acid, capric acid 含量이 두드러지게 많았다. S. diastaticus의 glucoamylase 生産性, glucoamylase의 分離 精製, 酵素力價 그리고 酵素學的 特性에서 optimum pH는 5.0, optimum temperature는 55℃ 이었다. S. diastaticus와 S. uvarum을 母菌株로 이들 간의 protoplast fusion을 위한 基礎的인 硏究로서 두 菌株의 諸特性과 protoplast調製의 最適條件을 決定하고 protoplast의 regeneration 條件의 確立을 도모하였다.두 菌의 生育曲線에서 모두 培養開始 7~8 時間만에 對數期 中期에 到達되었으므로 protoplast 調製는 이 時期의 細胞를 쓰기로 하였다. Generation time은 S. diastaticus가 1.04, S. uvarum이 1.38 時間이었다. 細胞의 크기는 S. diastaticus 44.10?㎛³, S. uvarum 99.67㎛³로 S. uvarum이 2倍나 컸다. DNA 含量은 細胞 當 S. diastaticus 44.3fg, S. uvarum 37.6fg이었다. 30% glucose 및 soluble starch에 대한 두 菌株의 ethanol 醱酵能은 glucose에 對하여 S. uvarum 11.4%, S. diastaticus 8.9% 이었고 soluble starch에 對하여는 S. diastaticus 만이 6.9%이었다. 두 菌株는 generation time, 細胞크기 및 DNA 含量 等으로 보아 diploid strain임을 알 수 있었고, 融合株 選拔을 위한 marker 로는 Sacch. uvarum의 melibiose 資化能의 차이를 利用할 수 있음을 밝혔다. Protoplast의 調製에는 β-glucuronidase와 Zymoyase를 使用하였는데 두 酵素 反應最適條件은 β-glucuronidase는 pH 8.0에서 10% 濃度의 溶液으로, Zymolyase는 pH7.5에서 20㎛/ml의 濃度의 溶液으로 하여 모두 70分間 處理하는 것으로 決定하였으나 이 정도의 處理時間에서는 protoplast가 극히 不安定하게 되어 regeneration frequency가 떨어지는 것을 確認하였으며, 特히 Zymolyase 處理로 얻어진 protoplast의 regeneration率이 낮은 것은 Zymolyase中에 不純物로 微量 混在한 protease가 protoplast의 노출된 membrane-bound protein을 分解함으로써 protoplast를 破壞시키기 때문인 것으로 추측되었다. 融合實驗에 利用할 수 있을 정도의 regeneration frequency를 얻기 위해서는 Zymolyase를 45分間 處理하여 얻은 protoplast를 1.5%의 polyvinylpyrrolicone이 加해진 OYPD培地에서 重層法으로 展開하여 regeneration시키는 것이 좋은 것으로 판명되었다. As preliminary steps of protoplast fusion between Saccharomyces diastaticus and S. uvarum to develop a fusant of higher ethanol production from starch, characteristics of the two presumptive parent strains, optimal conditions for protoplast preparation and conditions for highrer regeneration frequency were investigated. To determine flavor characteristics of the parent strains, neutral and acidic flavor fractions were extracted from liquids fermented by S. diastaticus and S. diastaticus + S. uvarum with methylene chloride and diethly ether. The liquid by the mixed culture produced more ethly acetate, ethyl undecanoate, n-propanol, n-butanol, lauric acid, caprylic acid and capric acid than that by S. diastaticus. Glucoamylase from S. diastaticus was purified and activity, productivity, and characteristics were determined. Optimum conditions for the enzyme were pH 5.0 and 55℃. The two strains reached logarithmic phase in 7-8h during growth and the generation time was 1.04 in S. diastaticus and 1.38 in S. uvarum. Cell size and DNA content per cell of S. diastaticus were 44.10㎛³and 44.3 fg, and for S. uvarum, 99.67㎛³and 37.6fg. Ethanol productivities of S. diastaticus were 8.9% from 30% glucose and 6.9% from 30% starch and 11.4% from glucose with S. uvarum. Through determination of generation time, cell size, and DNA content per cell, both strains appeared as diploids, and differences in assimilability of melibiose and soluble starch of the two strains were selected as markers to determine the fusant. The optimal condition for protoplast formation was treatment of both strains with 10% ß-glucuronidase at pH 8.0 or 20㎍/ml Zymolyase at pH 7.5 for 70 min. While the regeneration frequencies were very low at 70min exposure to Zymolyase because of the instability of protoplasts, the yeasts treated for 45min were better for regeneration. The regeneration frequencies were also enhanced by 3-6 times when the regeration was carried out with 1.5% polyvinylpyrrolidone which stabilized protoplasts.

      • Interpretation of cryogenic-temperature Charpy fracture initiation and propagation energies by microstructural evolution occurring during dynamic compressive test of austenitic Fe-(0.4,1.0)C-18Mn steels

        Kim, H.,Park, J.,Jung, J.E.,Sohn, S.S.,Lee, S. Elsevier Sequoia 2015 Materials science & engineering. properties, micro Vol.641 No.-

        In the present study, Charpy impact energy (E<SUB>T</SUB>) composed of fracture initiation energy (E<SUB>I</SUB>) and propagation energy (E<SUB>P</SUB>) of austenitic Fe-(0.4,1.0)C-18Mn steels was evaluated in the temperature range from room to cryogenic temperatures by an instrumented Charpy impact tester, and was interpreted by microstructural evolution of dynamically compressed specimens. In the 1.0C-18Mn steel, the E<SUB>I</SUB> and E<SUB>P</SUB> decreased slightly with decreasing temperature, but the E<SUB>P</SUB>/E<SUB>T</SUB> ratio was kept to be about 0.5. In the 0.4C-18Mn steel, the E<SUB>I</SUB> remained almost constant or slightly decreased with decreasing temperature, while the E<SUB>P</SUB>/E<SUB>T</SUB> ratio steadily decreased, thereby leading to the lower (about 30%) cryogenic-temperature E<SUB>T</SUB> than that of the 1.0C-18Mn steel. Under the dynamic compressive loading, a considerable number of ε-martensites were formed in the 0.4C-18Mn steel, whereas they were not found in the 1.0C-18Mn steel, and their volume fractions increased steadily with decreasing temperature. This γ→ε-martensite transformation was attributed to the decrease in stacking fault energy, and resulted in the very low E<SUB>P</SUB> and resultant E<SUB>T</SUB>.

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