Effect of Mechanical Alloying on the Microstructural Evolution of Al60Cr30Si10 Alloys Processed by Spark Plasma Sintering

Jeong‑Han Lee,Ik‑Hyun Oh,Jun‑Ho Jang,Ju‑Hun Kim,Sung‑Kil Hong,Hyun‑Kuk Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.5

In this study, Al, Cr and Si fine powders were alloyed by planetary ball milling to investigate their microstructural evolution,following their mechanical alloying behavior. The formation of Al(Cr) supersaturated solid solution by the Cr grainsembedded in Al-matrix, which contributed substitutional structure is discussed in relation to their structural evolution inaccordance with the distortion of a crystal lattice. The compacts of Al–Cr–Si alloys were prepared by rapid sintering withina short time by dense consolidation above the density of 99.9% as the formation of intermetallics, except in the case of thedistribution of single-phases induced by the Al-melting. The formation behavior of intermetallics was dominated by dependenceon the structures of the milled-powder and subsequent sintering temperature. To estimate the consolidated behaviorsof compacts, various approaches derived from TEM and XRD analysis were taken to obtain microstructural evidences ofthe inter-diffusion, following the presence of thermally stable intermetallics.

Influence of Phase Composition in TiAlSiN Hard Coatings on the Evolution of Structure and Mechanical Properties

Jeong‑Han Lee,Ik‑Hyun Oh,Jun‑Ho Jang,Ju‑Hun Kim,Sung‑Kil Hong,Hyun‑Kuk Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.3

The aim of this study is to investigate the structural evolution and mechanical properties of TiAlSiN coatings when processedby the arc ion plating method. To form a hard coating, Ti, Al, and Si powders were mechanically alloyed by planetary ballmilling; the powders were then densely compacted during a rapid sintering process into a ternary system coating, i.e. TiAlSi. The evolution of the structural phase from a powder to a compact material is dominated considerably by phase states suchas a supersaturated solid solution or intermetallic compounds. In the case of coating layers, the factors that determine thestructural evolution are associated with the phase stability of the nano-crystalline structure that in turn is associated withthe Ti/Al composition ratio. Motivated by this, we performed experiments to investigate the distribution of microstructures;the material’s binding energy, quantitative properties, transformation of crystal structure, and distribution of amorphous/crystalline were all recorded. In particular, the relationship between the physical and chemical properties during the coatingprocess is considered to be the dominant factor controlling the orientation and morphology of that zone (1, T, and 2). TheTiAlSiN coating layer was found to have hardness above 45 GPa and an adhesion above 100 N. In other words, understandingthe evolution and structure of TiAlSin helped us to produce a material with excellent properties that can be used as a hardcoating. Specifically, these properties were induced by a grain refinement of the nano-crystalline structure that correspondsto an increase in the silicon nitride contents.

형질전환 제초제저항성 벼 밀양 204호의 농업적 특성

정응기,이기환,원용재,박향미,전남수,최준호,구연충,한창덕,은무영,김태산,남민희 Plant molecular biology and biotechnology research 2005 Plant molecular biology and biotechnology research Vol.2005 No.

This study was conducted to investigated the major characteristics of genetically modified rice of "Milyang 204" originated from Dongjinbyeo compared to a non-transgenic rice varieties Dongjinbyeo and Junambyeo. Basta resistant transgenic rice lines carrying bar gene produced by the Yeongnam Agricultural Research Institute were evaluated for their agronomic characters. The transgenic Japonica rice of "Milyang 204" showed inferior phenotypic traits compared to a non-transgenic rice variety Dongjinbyeo and Junambyeo. On the basis of UPOV (Union Internationale Pour la Protaection des Obtentions Vegetables) and NSMO(National Seed Management Office) the transgenic "Milyang 204" showed difference in some traits out of some agronomic traits, such as leaf color, angle of flag leaf, number of spikelets, culm length, white core and white belly compared to the nontransgenic varieties rice.

대장암종에서 암관련 유전자들의 Promoter Methylation과 암종 발생 및 진행과의 관게에 대한 연구

정동준,이정은,민영기,조성우,백무준,양승하,김의한,김창진 순천향대학교 교수학습개발센터 2004 Journal of Soonchunhyang Medical Science Vol.10 No.3

The colorectal corcinoma is one of the most common malignant tumor in Korea and its carcinogenic mechanism has not been elucidated exactly yet. So far, the most common carcinogenic mechanism has been known to be multiple genetic changes. But, the CpG island hypermethylation has been revealed to be one of the most important carcinogenic mechanism second to the genetic changes. The epigenetic changes characteristically imprint and transfer to the next generation without changes of nucleotide sequences. When the CpG island of promoter or 5'- exon 1 of a specific gene is methylated by DNA methyltrasferases (DNMTs), the gene expression is inhibited. Carcinogenic mechansisms by promoter methylation has been well known, but the progression of the cancer has not been elucidated yet. The molecular researches on the carcinogenic mechanisms largely depended on the tumor tissue containing various components of cell, due to difficulties in harvesting pure homogeneous tumor cells. Promoter methylatonof the cancer related genes as APc, hMLH2, p16, DAP-K and MGMT in 50 cases of sporadic colorectal carcinoma was studied. The pure normal colorectal epithelial cells, and cancer cells from superficial and deep invasive portion were harvested respectively by laser captured microdissection(LCM), and DNA was extracted from them. The promoter methylation was studied by methylation specific poymerase reaction (MSP) after bisulfite modification of the DNA and the expression of the genes by immunohistochemistry. The results suggests that promoter methylation of the cancer related genes are closely related with the colorectal carcinogenesis and it occurrs from early phase of carcinogenesis, progressing constantly to the late stage. And the promoter methylation of normal epithelial cells increased by age. The p15, known to be the genes related to hematologic malignancy, was closely related to the colorectal carcinoma as well.

스위치드 릴럭턴스 전동기를 위한 구동시스템의 역률개선과 고효율에 관한 연구

한대희,최준혁,윤용호,정동효,김도군,원충연 성균관대학교 2003 학술회의지원논문목록집 Vol.2003 No.-

Switched Reluctance Motor (SRM) offers the advantages of simple and robust motor construction, high speeds and high efficiencies over a wide operating range of torque and speed, excellent controllability. However, SRM has the disadvantages of high current harmonics, and low power factor because of a capacitor filter is inserted in the power converter and inductance of SRM is high, it has pulse waveform of current. This paper deals with an energy efficient converter fed SRM system with the reduced harmonics and improved power factor and with higher efficiency. The validity of the proposed scheme is verified via experiment. We are implemented the proposed control system using 8OC196KC micro-controller.

'1998 한국인 우울증 선별의 날' 참가자들의 사회인구통계학적 특성과 우울증 선별검사 결과

한상익,이성필,고효진,박원명,장계호,유태열,전태연,채정호,방승규,김광수,최보문,이정태,백인호 大韓神經精神醫學會 1999 신경정신의학 Vol.38 No.5

연구목적 : 1998년 정신건강의 날 기념 한국인 우울증 선별의 날 행사에 자발적으로 참여한 참가자들의 사회인구 통계학적 특성을 분석하고 우울증 선별검사 결과를 평가하기 위하여 본 연구를 시행하였다. 방 법 : 8개 병원에서 얻어진 619명의 자료를 사용하여 선별검사로 밝혀진 우울증의 유병율과 사회인구통계학적 특성 및 응답자의 정신과적 치료를 포함한 과거력 등을 조사하였다. 결 과 : 우울증 척도 점수는 응답자 전체 평균 57.5±13.8로 경도의 우울 증상이 있는 것에 해당되었다. 전체 응답자의 69.5%(430명)가 최소한 경도 이상의 우울 증상을, 43.1%(267명)가 중등도 이상의 우울 증상을, 18.4%(114명)가 고도의 우울 증상을 보였다. 고도의 우울 증상이 있는 응답자의 56.8%와 중등도의 우울 증상이 있는 응답자의 63.9%가 정신과 치료를 받은 적이 전혀 없었다. 나이가 29세 이하인 것과 전임근무 중인 직업상태는 각각 나이가 60세 이상인 것과 직업이 없는 것에 비교하여 우울증으로부터 보호하는 인자임을 시사하였다. 결 론 : '1998 한국인 우울증 선별의 날' 행사를 통하여 많은 우울증 환자들을 선별해낼 수 있었고, 이들의 우울 증상은 몇몇 사회인구통계학적 특성과 유의한 관계가 있음을 확인하였다. 우울증 선별의 날 행사를 통한 우울증에 대한 교육과 우울증 선별검사는 치료받지 못하고 있는 우울증 환자 및 기존의 치료 중인 환자 모두에게 유용한 프로그램임을 알 수 있었다. Objectives : This study was performed to analyze the sociodemographic characteristics of participants in '1998 Korean Depression Screening Day' and to evaluate the results of the screening test. Methods : By using the survey results of 619 volunteers from 8 hospitals, the authors examined the prevalence of depression detected at the screening test and sociodemographic characteristics and the psychiatric treatment history of respondents. The assessment measure was the Zung Self-Rating Depression Scale. Results : The mean depression score of all participants was 57.5±13.8 and it came under mild depression. Of all participants, 69.5%(N=430) had at least mild depressive symptoms, 43.1%(N=267) had at least moderate symptoms, and 18.4%(N=114) had severe symptoms. Never have 56.8% of respondents in the severely depressed range and 63.9% of those in the moderately depressed range had psychiatric treatment. The results suggest that the age group of 29-year-old or younger(relative to 60-year-old or older group) and full-time employment status(relative to unemployment) are protective factors of depression. Conclusions : By '1998 Korean Depression Screening Day', many depressed patients were detected and their depressive symptoms had statistically significant relationships with some sociodemographic characteristics. The results suggest that the education and screening test programs for depressive illness facilitated by Depression Screening Day are useful to the patients regardless of being under current treatment or not.

주요 우울장애에서 Cytotoxic T Lynphocyte Antigen(CTLA-4) 유전자의 다형성

전태연,배치운,김병균,채정호,박원명,김광수,유태열,한훈 大韓神經精神醫學會 2001 신경정신의학 Vol.40 No.5

연구목적 : 세포의 면역 기능 조절에 관여하는 CTLA-4의 유전자 다형성을 분석하여 주요 우울장애와의 면역 유전학적 관련성을 알아보고자 하였다. 방 법 : DSM-Ⅳ진단 기준에 따라 주요 우울장애로 진단된 환자 77명을 선정하였으며 가톨릭대학교 의과대학 조혈모세포은행에서 보유하고 있는 149명의 정상 한국인 자료를 대조군으로 사용하였다. 전혈에서 DNA를 추출하였으며 중합효소반응으로 CTLA-4유전자 exon 1 부위를 증폭한 후 SSCP방법으로 유전?? 형별 분석하였다. 결 과 : 대조군과 주요 우울장애 환자군 사이의 CTLA-4 유전자형과 대립유전자의 발현 빈도를 비교시 유의한 차이가 없었다. 결 론 : 본 연구 결과 exon 1 CTLA-4 유전자형 및 대립유전자의 발현빈도는 주요 우울장애 환자군과 정상 대조군 사이에 차이가 없어, exon 1 영역은 후보 유전자로서의 가능성이 없었다. 향후 연구에서는 다양한 변인들에 따라 대상군을 임상적으로 동질성을 지닌 집단으로 세분하여 조사대상 유전자와의 관련성에 대한 연구가 이루어져야 하겠다. Objectives : This study was carried out to explore the relationship between major depressive disorder and CTLA-4 which is related to the immunologic function such as T cell regulation. Methods : Among the korean patients diagnosed as major depressive disorder according to DSM-Ⅳ, 77 patients without neurological illness, hormonal disorder, or comorbid mental illness were selected. The stored data of 149 normal Koreans from the Catholic Hemopoietic Stem Cell Bank of Korea, were used as a normal control group. The data of Korean control group were compared with those of the studies of different ethnics. DNA was extracted from whole blood and the exon I region of CTLA-4 gene was amplified by polymerase chain reaction. Gene typing was performed by using SSCP and then, the results were assessed. Results : There were no significant differences in genotype frquencies of CTLA-4*G/G, CTLA-4*G/A, and CTLA-4*A/A between the patients with major depressive disorder and the control group in Korean population(48.1% vs 46.3%, 41.6% vs 39.6%, 10.3% vs 14.1%, respectively).There were no significant differences in allelic frequencies of CTLA-4*G and CTLA-4*A between the patients with major depressive disorder and the control group in Korean population(68.8% vs 66.1%, 31.2% vs 33.9%, respectively). Conclusion : Considering negative result for the association of the exon I polymorphism of CTLA-4 gene with major depressive disorder in this study, the exon I polymorphism does not appear to be possible candidate gene for major depressive disorder. Moreover, further systematic researches including diverse clinical variables would required.

냉각탑용 수분배기의 특성에 관한 연구

전유신,최석천,이용훈,김세현,정효민,정한식 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-

The main purpose of this research is the investigation of water distributer. The water distributer of this research is installed in evaporative cooling tower system. The performance of this cooling tower system depend on the evaporative surface, and there are many kinds of methods for increasing the evaporative surface. In this research, we introduced the two kinds of spraying system, one is the hole type with hole diameter 1, 2 and 3mm, and the other is the spray nozzle types with nozzle tip diameter of 1 and 2mm. As the experimental results, the case of diameter 2mm showed the best performance.

물리학 선량법을 이용한 갑상선암의 개인별 최대안전용량 I-131 치료법 개발과 유용성 평가

김정철,윤정한,범희승,제갈영종,송호천,민정준,정환정,김성민,허영준,이명호,박영규,정준기 대한핵의학회 2003 핵의학 분자영상 Vol.37 No.2

목적 : 분화갑상선암 환자에 대한 방사성옥소(I-131) 치료는 재발율과 사망률을 감소시키는 효과적인 치료법이지만, 치료용량을 증가시킴으로써 치료율을 향상시킬 수 있는지에 대해서는 아직 논란이 있다. 본 연구에서는 최대허용선량 치료법의 효용성을 검증하고자 하였다. 대상 및 방법 : 임상적 병기가 제3, 4병기이고, 6개월 이후에 I-131 전신스캔(이하 IWBS)과 혈중 thyroglobulin (이하 Tg), anti-thyroglobulin antibody (이하 ATA), 초음파검사 (이하 US) 및 F-18 FDG PET 등을 통해 치료여부를 확인할 수 있었던 58명(남:여=9:49, 평균연령 50±11세)의 유두상갑상선암 환자를 대상으로 하였다. 이중 11명은 제4병기, 47명은 제3병기였으며, 43명(남:여=4:39), 평균연령 50±11세)은 7.4 GBq 이하의 고식적인 저용량치료법으로 치료하였고, 9.25 GBq 이상의 고용량 치료를 받은 환자는 15명(남:여=5:10, 평균연령 50±12세)으로 고용량군에서 남자가 더 많았으나 연령의 차이는 없었다. 고용량군 환자 모두에서 추적용량의 방사성옥소(평균 77±3 MBq)를 경구 투여한 후 혈중 방사능소실곡선을 통해 최대허용선량(maximum permissible dose, 이하 MPD)을 계산하였으며, 7명에서는 말초혈액림프구의 중기염색체분석법에 의해 생물학적으로 MPD를 계산하였다. 14명에서는 치료용량의 방사성옥소를 투여한 후 혈중 방사능소실곡선을 통해 MPD를 계사하였다. 완전치유(complete response, 이하 CR)는 IWBS에서 병소가 없어지고, 혈중 Tg치가 1 ng/mL 이하로 감소한 경우로 정의하였으며, 부분치유(partial response, 이하 PR)는 IWBS에서 병소가 없어졌더라도 혈중 Tg, ATA치가 높거나, US 또는 PET 검사에서 병소가 남아있는 경우로 정의하였다. 치료후 IWBS에서 병소가 오히려 증가하거나 변함없는 경우는 없었다. 방사성옥소 치료에 의한 부작용은 입원기간 중 타액선이 현저하게 붓고 통증이 있거나, 구토를 심하게 하는 경우, 그리고 퇴원후 1개월째 백혈구수가 20% 이상 감소한 경우로 정의하였다. 결과 : 양 군간에 연속적인 수치변화를 비교하는 경우는 paired t-test를 이용하였으며, 대상군간 치료효과와 부작용의 비교는 chi-square test를 이용하였다. p값 0.05 미만을 통계적으로 유의한 차이로 인정하였다. 고용량군 환자 모두에서 추적용량과 치료용량의 방사성옥소 투여 후 혈액의 피폭선량은 각각 0.012±0.3 Gy, 1.66±25 Gy였으며, 방사성옥소 투여 후 혈액에 전달되는 피폭선량은 추적용량보다 치료용량에서 더 많았고 (1.21: 166 rad, p<0.001), 방사성옥소 1 mCi당 혈액에 전달되는 피폭선량은 차이가 없었다(0.58±0.1 vs. 0.56±0.1 rad/37 MBq, p=0.34). 추적용량 방사성옥소 투여 후 구한 MPD는 평균 13.3±1.9 GBq (9.7 ~ 16 GBq) 이였고, 치료용량 방사성옥소 투여 후 구한 MPD는 평균 13.8±2.1 GBq (10.4 ~ 16.3 GBq)로 유의한 차이가 없었으며 (p=0.20), 두 수치간에는 유의한 상관 관계가 있었다(r=0.8, p<0.0001). 7명의 환자에서 말초혈액림프구 중기염색체 분석법으로 MPD를 측정하였는데 혈액의 피폭선량은 1.78±0.03 G였으며, 같은 환자에서 혈중 방사능소실곡선으로부터 구한 피폭선량은 1.54±0.03 G로 유의하게 낮았으나 (p=0.01), 두 측정치 간에는 유의한 상관관계(r=0.86, p=0.01)가 있었다. 저용량 치료군 43명 중 22명(51.2%)에서 완전치유를 보였고 21명(48.8%)에서는 부분치유를 보인 반면 고용량 치료군 15명 중 12명(80%)에서 완전치유를 보였고 3명(20%)에서만 부분치유를 보여 고용량 치료군에서 유의하게 높은 완전치유를 얻을 수 있었다(p=0.05). 한편 부작용 발생빈도는 저용량 치료군 43명 중 13(30.2%), 고용량 치료군 15명 중 6명(40%)로 양군간에 유의한 차이가 없었다(p=0.46). 임상적인 병기, 연령 및 성별에 따라서는 치유의 차이가 없었다(p>0.05). 결론 : 혈중소실곡선으로부터 MPD를 결정하고 이를 토대로 환자 개개인별로 적절한 선량을 선택하여 치료하는 방법은 부작용을 최소화하면서도 치료효과를 높일 수 있는 매우 유용한 치료법이며, 고위험군 분화갑상선 암 환자에게 가장 적절한 치료법이라고 사료되었다. Purpose: Radioiodine (1-131) therapy is an effective modality to reduce both recurrence and mortality rates in differentiated thyroid cancer. Whether higher doses shows higher therapeutic responses was still debatable. The purpose of this study was to validate curve-fitting (CF) method measuring maximum permissible dose (MPD) by a biological dosimetry using metaphase analysis of peripheral blood lymphocytes. Materials and Methods: Therapeutic effects of MPD was evaluated in 58 patients (49 females and 9 males, mean age 50±11 years) of papillary thyroid cancer. Among them 43 patients were treated with ≤7.4 GBq, while 15 patients with ≥9.25 GBq. The former was defined as low-dose group, and the latter high-dose group. Therapeutic response was defined as complete response when complete disappearance of lesions on follow-up 1-131 scan and undetectable serum thyroglobulin levels were found. Statistical comparison between groups were done using chi-square test. P value less than 0.05 was regarded as statistically significant. Results: MPD measured by CF method using tracer and therapeutic doses were 13.3±1.9 and 13.8±2.1 GBq, respectively (p=0.20). They showed a significant correlation (r=0.8, p<0.0001). Exposed doses to blood measured by CF and biological methods were 1.54±0.03 and 1.78±0.03 Gy (p=0.01). They also showed a significant correlation (r=0.86, p=0.01). High-does group showed a significantly higher rate of complete response (12/15, 80%) as compared to the low-dose group (22/43, 51.2%) (p=0.05). While occurrence of side effects was not different between two groups (40% vs. 30.2%, p=0.46). Conclusion: Measurement of MPD using CF method is reliable, and the high-dose 1-131 therapy using MPD gains significantly higher therapeutic effects as compared with low-dose therapy.

兒童의 造形能力(繪畵, 彫塑)과 他 敎科成積과의 相關에 關한 硏究

金正熹,韓進九,李吉鍾,金相俊 春川敎育大學 1985 論文集 Vol.25 No.-

The main purpose of this sutdy is ultimately to help improve art education by clarifying and interpreting the correlation of modeling ability to that of other subjects taught in primary schools. This research covered a total of 600 children of two schools : one in Chunchon city and the other in Chunsong county. As the marks of all the subjects are scaled by the absolute achievement evaluation method, the average of the tatal subjects showed a high mark of 4.23. But our research team, having measured their modeling ability in relative evaluation method, marked only 3.31 point in average. Notwithstanding this discrepancy, the correlation between the marks of the toal subjects and the drawing revealed a strikingly low coefficient of 0. 18 and 0.23 between the total and sculpturing ; and 0.20 between the tatal and modeling as a whole. Thus, it is definite that any argument for high correlation among achievements in subjects cannot apply to art subject. The result of this research may be revised by drawing data from markings of identical evaluation method, but the difference will be of little consequence.