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하수체척출(下垂體剔出) 숫흰쥐에 있어서 Testosterone Propionate의 투여(投與)가 부신(副腎)에 미치는 영향(影響)
김관영,이규승,정영채,Kim, K.Y.,Lee, K.S.,Chung, Y.C. 충남대학교 농업과학연구소 1974 Korean Journal of Agricultural Science Vol.1 No.1
This study was made to investigate whether there would be any direct relationship between testis and adrenal gland. After the iadministration of testosterone propionate to the hypophysectomized male rats, weight of adrenal glands, each zona rates in adrenal gland and histological changes measured from the 1st day to 56th day of the experimental period. The results obtained were as follows; 1. For the weight changes of thyriod gland, it showed a similar changes between the hypophysectomized and the testosterone propionate treated-hypophysectomized group. However, the weight of adrenal glands for the treatment groups were decreased as the time passed as compared to the control group, and the difference were highly significance at the 7th day and there on. 2. For the zona rates in adrenal gland the changes were similar between the hypophysectomized and the testosterone propionate treated-hypophysectomized group. Zona fasciculata and reticularis were decreased rapidly as time passed as compared to the control group, and the difference were significant at the 7th day and highly significant at the 14th day and there on. Adrenal medulla tended to increase, showing a significance with P<0.05 at 7th day, and P<0.01 at 14th day and there on. Zona glomerulosa showed no differences among the groups. 3. Histological changes for the testosterone propionate treated-hypophysectomized group were similar to the hypophysectomized group. Of adrenal gland, zona fasciculata and reticular is were degenerated and lost their function as time passed after treatment, and zona glomerulosa and adrenal medulla were observed not bo changed. 4. Since there were re no differences in weight changes of adrenal glands, the zonarates in adrenal gland and histological changes between the hypophysectomized and testosterone propionate treated-hypophysectomized group, it would appear that there were no direct relationship between the testis and the adrenal gland, but the involvement of hypophysis might be necessary for the control mechanism.
ECO AZ31 마그네슘 합금의 인장, 고주기 피로 및 피로 균열 전파 변형 거동
김민종(M. J. Kim),김관영(K. Y. Kim),김세광(S. K. Kim),임현규(H. K. Lim),박중철(J. C. Pack),이기안(K. A. Lee) 한국소성가공학회 2014 한국소성가공학회 학술대회 논문집 Vol.2014 No.5
Tensile and fatigue deformation behaviors of newly developed ECO AZ31 alloy was investigated. Microstructure analysis, tensile, high cycle fatigue, fatigue crack propagation tests were conducted. In the microstructure observation, average grain size was 3.2㎛ for AZ31 alloy and 2.7㎛ for ECO AZ31 alloy. Alloys consisted of Mg matrix containing minute amounts of Mg17Al12, Al6Mn, Mg12(Al, Zn)49phases. Tensile results showed that the properties of ECO AZ31 alloy (T.S: 314.6MPa, Y.S: 188.7MPa, elongation: 20.2%) were superior to those of AZ31 alloy (T.S: 306.4MPa, Y.S: 177.6MPa, elongation: 17.7%). High cycle fatigue limit of AZ31 (set at 10<SUP>7</SUP> cycles) was 140MPa and that of ECO AZ31 alloy was 160MPa. Result of fatigue crack propagation experiment, both alloys showed similar fatigue crack propagation rate. The cause of better properties the new ECO alloy was also discussed based on the fractography observations.
Al 7003 합금의 인장 및 피로 특성에 미치는 열처리(T5, T6)의 영향
김민종 ( M J Kim ),김관영 ( K Y Kim ),어광준 ( G J Euh ),임영목 ( Y M Rhym ),이기안 ( K A Lee ) 대한금속재료학회(구 대한금속학회) 2015 대한금속·재료학회지 Vol.53 No.3
A7003 alloy underwent T5 and T6 heat treatments (T5: 90 ℃ for 5 hrs and 150 ℃ for 16 hrs; T6: 470 ℃ for 3 hrs followed by artificial aging at 80 ℃ for 14 hrs, and 120 ℃ for 42 hrs); the tensile and fatigue properties of the treated materials were then examined. High-cycle fatigue tests were conducted at R (stress ratio)=0.1, and f (frequency)=20 Hz. The average grain size of A7003-T5 alloy was 3.8 μm, and that of A7003-T6 alloy was 4.1 μm. Both of the alloys were found to have MgZn2 (?), Fe-based intermetallic phases in their aluminum matrix. A7003-T6 alloy had finer MgZn2 (?) phases distributed more evenly than A7003-T5 alloy. Tensile test results showed that A7003-T6 alloy had higher strength (Y.S. & T.S.) and lower elongation compared to those of A7003-T5 alloy. High cycle fatigue results showed that A7003-T6 alloy had longer fatigue limit (320 MPa) than that (290 MPa) of T5 alloy. A7003-T6 alloy was found to perform better in all other fatigue stress conditions, too. Based on the observation of tensile and fatigue fracture surfaces, the correlations between microstructures made by heat treatments and mechanical/fatigue properties were also investigated along with the fatigue deformation mechanism of A7003 alloy.(Received April 22, 2014)
Modified 7075-T73 알루미늄 합금의 고주기 피로 변형 거동
김관영(C. Y. Kim),김선호(S. H. Kim),김세광(S. K. Kim),조규상(K. S. Cho),이기안(K. A. Lee) 한국소성가공학회 2012 한국소성가공학회 학술대회 논문집 Vol.2012 No.5
Fatigue behavior of new developed Modified 7075-T73 alloy was investigated. Microstructure analysis, tensile test, high cycle fatigue test were conducted in this study. In the microstructure observation, average grain size of 2.9 um was measured and reduced oxide content was detected. The alloy consisted of AI matrix, AlzCuMg, MgZnz, and additional Ca including phase. Tensile properties of Modified 7075-T73 alloy were higher than those of convention 7075 AI alloy. Fatigue properties were significantly improved compared to those of conventional alloy (Fatigue limit of 340MPa). The superior tensile and fatigue properties of Modified 7075-T73 alloy were mainly attributed to grain size refinement, homogeneous distribution of 2od phases, and reduced oxides.
Eco ADC12(Al-Si-Cu) 합금의 인장 및 고주기 피로 변형 거동
김관영(G. Y. Kim),김규식(K. S. Kim),김세광(S. K. Kim),윤영옥(Y. O. Yoon),이기안(K. A. Lee) 한국소성가공학회 2013 한국소성가공학회 학술대회 논문집 Vol.2013 No.5
The effects of Eco-Mg addition (0.6% and 0.8% wt%) on the microstructure development and tensile, high cycle fatigue properties of Eco-ADC 12 alloys have been investigated. Eco-ADC 12 alloys is made using Eco-Mg(Mg-Al₂Cu) in place of element Mg during the manufacture of alloy ADC 12. Microstructure analysis, tensile test, high cycle fatigue test were conducted in this study. The alloy consisted of α-Al, eutectic Si and Al₂Cu phase whit higher pore fraction. The tensile and high cycle fatigue results indicated that the fatigue strength of the Eco-ADC 12(0.8%) alloy was higher than those of the Eco-ADC12(0.6%) alloy. This study also attempted to clarify the micro-mechanism of fatigue deformation behavior related with its microstructure.
Modified 2024 알루미늄 합금의 인장 및 피로 연구
김관영(G. Y. Kim),김선호(S. H. Kim),윤영옥(Y. O. Yoon),김세광(S. K. Kim),조규상(K. S. Cho),이기안(K. A. Lee) 한국소성가공학회 2012 한국소성가공학회 학술대회 논문집 Vol.2012 No.10
In this study, the microstructures and mechanical properties of the recently developed Eco-2024-T3 alloy were examined. Eco2024 is made using Eco-Mg(Mg-Al₂Ca)in place of element Mg during the manufacture of alloy 2024-T3. This is an alloy that has economic advantage and excellent properties. Alloy Eco2024 showed smaller crystal grains that were distributed more evenly compared to the existing alloy 2024-T3. It consisted of Al matrices containing minute amounts of Al₂CuMg, Al₂Cu and Ca phases and showed microstructures with reduced amounts of Fe phases or oxide. As a result of tensile test, this alloy exhibited yield strength of 413MPA, tensile strength 527㎫, and elongation of 15.4%. In other words, it showed higher strength than the existing alloy 2024 but was similar to the existing alloy 2024 in terms of elongation. In fatigue tests, alloy Eco2024-T3 recorded fatigue limit of 330 ㎫ around 80% of its yield strength this is a much more excellent property compared to the existing alloy 2024-T3, which has fatigue limit of 250㎫. Based on the aforementioned results, the correlation between the excellent mechanical properties of alloy Eco2024-T3 and its microstructure was examined.
Modified 7050-T7451 알루미늄 합금의 고주기 피로 변형 거동에 미치는 Ca첨가의 영향
김관영(G. Y. Kim),김규식(K. S. Kim),김세광(S. K. Kim),조규상(K. S. Cho),이기안(K. A. Lee) 한국소성가공학회 2013 한국소성가공학회 학술대회 논문집 Vol.2013 No.5
This study examined the microstructures and mechanical and fatigue properties of the recently developed Eco7050-T7451 alloy. Eco7050-T7451 is made using Eco-Mg(Mg-Al₂Ca) in place of the element Mg during the manufacture of alloy 7050-T7451, having economically advantageous and superior properties. In the microstructure observation, average grain size was measured to be 5.2㎛. It consisted of Al matrix containing minute amounts of Al₂CuMg, MgZn₂, And Ca phases and showed microstructure with reduced amounts of Fe phases or oxides. Tensile test exhibited that this alloy had yield strength of 509 MPa, Tensile strength of 559 MPa, elongation of 13.8 %, which showed greater strength than conventional alloy 7050 but the same elongation. Fatigue properties were significantly improved compared to those of conventional alloy (fatigue limit of 350MPa). The superior tensile and fatigue properties of Modified 7050-T7451 alloy were mainly attributed to grain size refinement, homogeneous distribution of 2<SUP>nd</SUP> phases, and reduced oxides.
MIM(금속분말사출성형)공법으로 제작된 Fe-2%Ni합금의 미세조직 및 기계적 특성
조규상(K. S. Cho),김민종(M. J. Kim),김관영(K. Y. Kim),정재옥(J. O. Jeong),박시우(S. W. Park),이기안(K. A. Lee) 한국소성가공학회 2013 한국소성가공학회 학술대회 논문집 Vol.2013 No.5
Microstructure and mechanical properties of Fe-2%Ni alloy produced by MIM(Metal Injection Molding) were investigated. Microstructure analysis, tensile test, and high cycle fatigue test were conducted. In the microstructure observation results, non-regular grain and inhomogeneous ferrite and pearlite were appeared. Non-sintered C, Si, Mn including phases were also detected. As a result of tensile test, MIMed Fe-2%Ni alloy represented yield strength of 285,5 MPa, tensile strength 605.7 MPa, and elongation 6.02%. The tensile properties of MIMed Fe-2%Ni alloy showed higher elongation and similar strengths compared to those of conventional Fe-2%Ni alloy. High cycle fatigue limit was obtained as 440 MPa. Micro-mechanisms of tensile and fatigue deformation behaviors in MIMed Fe-2%Ni alloy were also discussed based on the fractography observation.