Effect of Electrochemical Hydrogen Charging Time on Hydrogen Embrittlement of the Hot-Rolled and Accelerated Cooling Treated API X70 Steel

Dong‑Su Bae,Un‑Bong Baek,Seung‑Hoon Nahm,Ilguk Jo 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.2

This study investigated the effect of the hydrogen charging time on the hydrogen embrittlement of hot-rolled and acceleratedcoolingtreated API X70 steel by using the electrochemical hydrogen charging method. Tensile and V-notch Charpy impacttest were completed for the specimens of hydrogen charged for 0, 2, 4, and 10 h, and then microstructural observation wereperformed. The tensile and yield strength tended to decrease slightly and the total elongation started to decrease rapidly up to2 h charging time and then these gradually decreased with the hydrogen charging time. The post-uniform elongation increasedslightly after the holding time of 2 h due to the occurrence of two-step stress reduction phenomenon and its mechanismhas suggested. The effect of the hydrogen embrittlement on impact absorption energy according to the hydrogen chargingtime were also investigated. The fracture surface of the hydrogen charged ones are generally composed of cleavage fracturesurfaces. It was demonstrated that the external cracks were formed on the outside of tensile tested specimen and the externalshape of the fracture portion was fractured without large elongation at hydrogen charged specimens.

Kim,Dong-jo

장재철,김동윤,박영순,전철,김동조 群山大學校 自然科學硏究所 1991 自然科學硏究 Vol.6 No.-

홍삼 추출물이 반치사량정도의 방사선(5Gy)에 조사된 생쥐조직 및 이들 조직에서의 효소활성에 미치는 영향을 관찰하기 위하여 ICR계 생쥐를 대상으로, 생리적 식염수군을 대조구군으로 하여, 홍삼 추출물 투여군과 방사선만을 조사한군 및 홍삼 추출물 투여후 방사선 조사군 등 4군으로 나누어 1일, 4일, 9일, 17일 및 30일 등 5회에 걸쳐 생체의 조직중 비장 및 고환에서의 중량 변화 및 GOT와 GPT의 활성을 측정하여 결과를 얻었다. 비장의 중량변화는 1일째 및 4일째 최소치를 보이다가 이후 증가추세를 보였으며, 고환의 중량 변화는 17일 이후 급격한 감소로 30일에도 증가하지 못했다. GOT의 활성도 변화는 비장에서는 초기에 현저히 증가했으며 이후 회복하는 경향이었다. 방사선 조사군들에서는 홍삼추출물 투여군이 방사선만을 조사한 군보다 빠르게 회복하는 경향이었으며 고환에서의 GOT활성은 매우 불안정하였다. GPT 활성도 변화는 비장, 고환에서 모두 초기에 증가하다가 점차 회복하는 경향이었으며 홍삼 추출물 투여후 방사선 조사군이 방사선만을 조사한군보다 빠르게 회복하는 경향이었다. 이러한 결과로 볼 때 홍삼 추출물은 방사선 조사에 의하여 기인된 비장 및 고환의 GOT와 GPT활성도 증가에 방호효과가 있다고 생각된다. This study was prepared to observe the change of tissues weight, glutamate oxaloacetate transminase(GOT) and glutamate pyruvate transminase(GPT) activities in the spleen and testis treated with red ginseng extract injection in the gamma ray irradiated mice. Groups were divided into control, red ginseng extract injection, irradiation after saline injection and irradiation after red ginseng extract injection. The spleen and testis weights were decreased at 17th day irradiation after saline injection and irradiation after red ginseng extract injection. The GOT activity showed earlier recovery at irradiation after red ginseng extract injection group than irradiation after saline injection group in the spleen. The GPT activity showed earlier recovery at irradiation after red ginseng extract injection group than irradiation after saline injection group in the spleen and testis. The above result suggest that red ginseng extract have the recovery effect on the change GOT and GPT activity after radiation injury in the spleen and testis of mice.

남자 초·중학생의 무산소성 작업능력과 무산소성 파워의 관계

정동식,정덕조,정성태,이병근,전태원,김은혜,이동규,정동춘 師範大學 體育硏究所 1998 서울大學校 體育硏究所論集 Vol.19 No.2

The critical power(CP) is the highest intensity to sustain for a long time without a fatigue. The anaerobic work capacity(AWC) is the highest anaerobic capacity to be provided by anaerobic energy system without the infection of hypoxia. The purpose of this study was to determine the relationship between AWC and AnP and to verify the validity of AWC. The subjects were consisted of 10 elementary and 10 middle school male students(12.8±1.3yrs, 159.3±12.1㎝, 49.4±11.8㎏). The critical power and anaerobic work capacity were calculated by work-time relationship after four cycle ergometry test to fatigue from 1 to 10 minute. The anaerobic power included Margaria-Kalmen test, Sargent jump and Wingate test. The main finding were as follows. The AWC of elementary and middle school students. were 6.47±2.63KJ and 11.10±3.01KJ. The AWC of elementary students was 58.3% of the middle school students's one. The AnP of elementary students were 47.2∼66.5% of the middle school students's one. And there were high correlation between AWC and AnP(0.64∼0.87, P<0.01). This study showed that AWC is useful index on AnP both elementary and middle school students.

음성 인식 헬스케어 시스템

신진우,조우승,조성빈,김재훈,정지은,사예지,백경동,박동규 순천향대학교 부설 산업기술연구소 2021 순천향 산업기술연구소논문집 Vol.27 No.2

As modern people's interest in health grows, wearable healthcare-related technologies that can collect biometric information and receive health-related services regardless of time and place are developing. This paper proposes the healthcare system based on voice recognition function. Unlike conventional wearable healthcare systems, the proposed system provides real-time telemedicine and diagnosis and the direct connection with doctors is possible through it. And almost all functions of the application in it are operated with voice commands to lower user access barriers. Because it deals with personal information including medical information, encryption algorithms have been applied between all data movements. Finally, the healthcare system proposed in this paper is expected to increase convenience in health care and reduce the medical gap.

관동맥질환에서 저밀도 지단백 입자 크기의 분포

임효영,김인숙,승기배,강동헌,전두수,장기육,박준철,이수영,홍순조,최규보 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.8

입자상 오염물질의 대기환경기준에 관한 연구

허정숙,남보현,황인조,김동술 경희대학교 환경연구소 1999 環境硏究 論文集 Vol.9 No.-

We provide various fundamental statistics for PM-10 based on air quality monitoring data('96-'98) operated by the Ministry of Environment. The purposes of this paper are to examine the distribution of PM-10 level computed on the basis of a reference method adapted by USEPA and to review national ambient air quality standards for particulate matter in Korea. When we calcualted the 3-year('96-'98) average of the annual mean PM-10 concentrations at 24 monitoring sites. 21 sites were not met 50㎍/m(annual PM-10 standard in USA). Especially. Duckchon-dong and Shinpyung-dong sites at Pusan were recorded the highest concentration. Also, when we considered the 3-year average of the 99^(th) percentile values, 14 sites including Ssangmun-dong at Seoul and Duckchon-dong at Pusan among 23 were classified non-attainment area exceeding 150㎍/m(24-hour PM-10 standard in USA). We suggest that the air quality standards for PM-10 and PM2.5 in Korea must be actually regulated based on scientific review and the public health.

70年代 中國에서 出土한 古典籍考

趙東元 부산대사학회 1985 역사와 세계 Vol.- No.9

스포츠 관광 활성화 개선방안에 관한 연구

조충현,김홍식,박은석,강성찬,이동헌 圓光大學校 附設 體力科學硏究所 2003 體力科學硏究 Vol.26 No.1

This study was conducted to investigate the effects of the marketing strategy based on the traditional wrestling, which affects the tour industry. The study used the simple random sampling method in the group of the Kwang-Ju district citizens. The group representatives were directly interviewed, and 277 interviewees replied with concern. The rest of the interviewees were not interested in the survey. The general characteristics of the interviewees -- gender, age, education, job, monthly salary. -- were used to analyze the items related to Sports Tourism in general. Sport Tourism in general Male interviewees had higher recognition over females in the interview. The rate of experience was low for both genders. According to their education, the satisfaction of sport tourism showed low rate. However, there were many answers where the interviewees, not depending on the age or gender, indicated that they will participate in the future. The policy recommended based upon the results of the study is as follows. There is a need for setting up a new strategy in order to increase participation of sports. Also, it is urgent to set up a sports theme center to raise professional sportsmen and to supply them to where they are needed.

T. S. Eliot 연구

조동현 대진대학교 1993 大眞論叢 Vol.1 No.-

Eliot's early works reveal a kind of vacant isolation while his later ones a kind of calm meditation. However there should be a 'significant unity' in them. He pursues through his whole works the overwhelming question of which answer will be the union with God In trying to find the meaning of true life, one must deny one's ego and the things of the world. But many people in Eliot's early poems up to The Waste Land were not detached from themselves and the things of the world. They lived the buried life of the underground and so they were neither alive nor dead It is not difficult to find out the religious and philosophical tendencies in his later works. In "Ash Wednesday", Eliot explains the many steps of the religious mind through the speaker in his poems who is similar to himself. In his poems the spiritual condition of the twentieth century is compared to the waste land, and the meaning of time on earth lies in the understanding of the unread vision, the Word of God Grasping the Word is related to the effort to go nearer to God The main theme of Four Quartets is the time and eternity. He is talking about human experiences that are of the moment and of the lifetime in the 'turning world'. In his experiences, man at the moment of apprehension perceives that two opposite but coexistent worlds are in conflict. Eliot has focused on the Incarnation as a symbol for the most significant union of opposites. The Incarnation is the point of 'intersection of the timeless / With time' Eliot's notion of time is the coexistence of present, past and future which are no more than a moment within the eternal now. His concept of the end and the beginning is nothing else than the death in this world and the religious rebirth, and the end and the beginning are also coexistent within the eternal now Thus Eliot's whole poetry is a vision in quest of God. At last he suffers the world of God.

肝Glycogen 生成에의 放射性 Glucose 및 아미노酸의 利用에 대한 食餌의 영향

曺準承,朴東烈 慶北大學校 1980 論文集 Vol.29 No.-

The rate of utilization of glucose or amino acids for liver glycogen synthesis was investigated in fed or 24-hour fasted albino rats weighing approximately 200g. Rats were administered intraperitoneally in a single dose of 4μCi of glucose-(U)-^14C with 100mg of glucose or amino acid mixture-^14C with 20mg of L-alanine per 100g body weight. Three hours later, the rats were sacrificed and the liver was analyzed for the determinations of glycogen content and activity of labeled carbon incorporated into the glycogen. The content of liver glycogen decreased from 1.2% of wet weight in the 24-hour fasted rats and remained low in the 72-hour fasted rats. In the fasted group, incorpration rate of glucose-(U)-^14C or amino acid mixture^-14C into liver glycogen was increased 2-or 4-fold, respectively, in compared with that of the fed group. And in the fasting state the incorporation rate of amino acid into liver glycogen was two-times higher than that of glucose. This result indicates that fasting stimulates glycogen synthesis in the liver from glucose and amino acids administered, and amino acid is to be more utilizable for the synthesis than glucose in the fasting state.