• Title/Summary/Keyword: life-history

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Fatigue Life Prediction of Weldment with Damage Mechanics (손상역학을 이용한 용접부의 피로수명예측)

  • Chung, Heung-Jin;Yoo, Byoung-Chan
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2008.04a
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    • pp.60-64
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    • 2008
  • According to previous research, welding-induced stress in steel structures can significantly affect the fatigue behaviour; it produces initial damage of weldiug part of structure locally and residual stresses reduce the fatigue strength after welding precess. In this study, through continuum damage mechanics, we can estimate the weldiug damage using the stress and strain history during welding process and the effect of welding residual stress for assessment of fatigue life. The variation of welding-induced stresses and strains need be traced precisely in advance for a reliable weldiug damage assessment. In this study, a damage and fatigue analysis techniques for steel structures with welding-induced residual stress are presented. First, We calculate the history of temperature according with welding process. And residual stress with a welding thermal history was evaluated by non-linear thermal stress analysis. Secondly, welding damage and fatigue life are estimated with kinetic damage law.

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Analysis of effects of burning in grasslands with quantifying succession stages by life-history traits in Kirigamine, central Japan

  • Kato, Jun;Kawakami, Mihoko
    • Journal of Ecology and Environment
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    • v.36 no.1
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    • pp.101-112
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    • 2013
  • To quantitatively analyze the effects of burning, we conducted a vegetation survey in the grasslands in Kirigamine, central Japan. We classified each species into stages of succession based on the life-history traits of the species and defined the score of the species in each stand based on the classification. We weighted the scores with a v-value, the product of coverage and height in the quadrat, and summed them to calculate the index of dynamic status. With these indices, we were able to quantitatively compare the stands in the study area and discern minute differences between the stands with different lengths of restoration periods since the disturbance of burning. These indices correlated with the v-value of trees, suggesting that the disturbance of burning seemed to affect the trees in the stand. We then calculated the growth of the tree species Pinus densiflora to evaluate its contribution to the index of dynamic status.

Underwriting of occupational cancer in korea (국내 직업성암의 언더라이팅)

  • Chung, Hun-Jong
    • The Journal of the Korean life insurance medical association
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    • v.27 no.2
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    • pp.80-84
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    • 2008
  • Now, we have experienced that the loss ratio of cancer insurance with prevalence of cancer increased. The insurance companies interest how the loss ratio of cancer insurance decrease. To decrease the loss of ratio of cancer, underwriting is very important. The underwriting of cancer are very important factors which are family history, habitual behavior and past history. We have spend the most of time under the occupational situation. Occupation may be very important factor causing cancer. But we neglect the occupation history. This article show how the underwriting of the occupational cancers in the field of occupation are managed Generally, Occupational cancers show special characteristic features. We know the characteristics of occupational cancer under the variety of occupation. For the underwriting of occupational cancer in Korea, we also understand the epidemiology of Korean occupational cancer with the varieties of occupation This article shows the characteristics of occupational cancer and epidemiology of Korean occupational cancers.

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Life History and Population Dynamics of Korean Woodroach(Cryptocercus kyebangensis) Populations

  • Park, Yung-Chul;Choe, Jae-Chun
    • Animal cells and systems
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    • v.7 no.2
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    • pp.111-117
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    • 2003
  • Ecological aspects of Cryptocercus kyebangensis life history were investigated via laboratory rearing and field observations. The number of antennal segments and head width were used to classify the first four instars. The results, which combine both the field collection and the laboratory rearing, indicate that eleven instars occur in C. kyebangensis. It supports the proposal on the number of instars of Park and Choe (2003c) based on field collections. A total of 388 nymps from 13 colonies were collected prior to winter to investigate overwintering stages. Of them,4% (n = 17) were the second instars, 57% (n = 220) were the third instars, and 39% (n = 151) were the fourth instars, respectively. Thus, most of them overwinter in the third or fourth instars. The results indicate that young nymphs of C. kyebangensis have to reach at least 3rd or 4th instar to survive low temperature environment of winter. According to seasonal dynamics of populations, C. kyebangensis reaches adulthood in the summer of the fourth or fifth year (4-5 yr span) after their birth.

Early Life History Characteristics of an Induced Hybrid Between Acheilognathus majusculus and Acheilognathus yamatsutae (큰줄납자루(Acheilognathus majusculus)와 줄납자루(Acheilognathus yamatsutae) 잡종의 초기생활사 특징)

  • Park, Jae-Min;Yoo, Dong-Jae;Han, Kyeong-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.54 no.2
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    • pp.170-179
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    • 2021
  • This study was conducted to identify taxonomic differences in the characteristics of Acheilognathus majusculus and A. yamatsutae during their initial life history via an interspecific hybridization experiment. Hatching time required 36 h for MY and 49 h for YM at 21.5℃, showing a significant difference of 13 h between the hybrids. The hatching rates of the cross-bred eggs were 30% for cross MY (A. majusculus♀×A. yamatsutae♂) and 40% for cross YM (A. yamatsutae♀×A. majusculus♂). The hatching larvae size was total length 3.13-3.43 mm in MY and total length 3.89-4.22 mm in YM, which was larger in YM. The hybridization test between A. yamatsutae and A. majusculus that live in the same water stream confirmed that no interspecific reproductive isolation occurred.

Early Life History Characteristics of an Induced Hybrid of Rhodeus ocellatus and Acheilognathus yamatsutae (흰줄납줄개(Rhodeus ocellatus)와 줄납자루(Acheilognathus yamatsutae) 잡종의 초기생활사 특징)

  • Park, Jae-Min;Han, Kyeong-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.55 no.2
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    • pp.137-145
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    • 2022
  • This study was conducted to identify the taxonomic differences in the characteristics of Rhodeus ocellatus and Acheilognathus yamatsutae during their early life history via an interspecific hybridization experiment. Results showed that the hatching rates of the cross-bred eggs were 60% for cross OY (R. ocellatus ♀×A. yamatsutae ♂) and 70% for cross YO (A. yamatsutae ♀×R. ocellatus ♂). The dorsal fin rays of YO were similar to those of R. ocellatus. The hybridization test of A. yamatsutae and R. ocellatus living in the same water stream revealed that no interspecies reproductive isolation occurred. OY and YO showed similar maternal and paternal characteristic. The juvenile of OY did not resemble both paternal and maternal fin rays, indicating a difference. The hatching larvae of the hybrids showed the morphological characteristics of their parents but varied in terms of the shapes of their parts.

Early Life History Characteristics of an Induced Hybrid Between Rhodeus ocellatus and Rhodeus notatus (흰줄납줄개(Rhodeus ocellatus)와 떡납줄갱이(Rhodeus notatus) 잡종의 초기생활사 특징)

  • Jae-Min Park;Kyeong-Ho Han
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.56 no.4
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    • pp.549-557
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    • 2023
  • This study aimed to investigate taxonomic differences in the early life history characteristics of Rhodeus ocellatus and Rhodeus notatus through an interspecific hybridization experiment. The hatching rates of the cross-bred eggs were 50% for the ON cross (R. ocellatus ♀×R. notatus♂) and 67% for the NO cross (R. notatus♀×R. ocellatus♂). Interestingly, the hatching time of the hybrids was longer than that of their parents. The newly hatched larvae exhibited distinct differences in their physical characteristics. The head of the adult fish protruded forward more than that of the ON cross. The pterygoid process was 45° for the ON cross and 90° for the NO cross. Furthermore, the tail shape of the ON and NO crosses closely resembled that of R. notatus.

Study on Structural Safety Analysis of Upper Arm (어퍼암의 구조적 안전성 해석에 대한 연구)

  • Cho, Jaeung;Han, Moonsik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.3
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    • pp.113-125
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    • 2013
  • This study analyzes upper arm as the part of suspension through the structural analyses of fatigue. Maximum displacement is shown at the knuckle joint connected with the bracket of automotive body. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. Maximum life at 'Sample history' or 'SAE transmission' can be shown with 60 or 3.5 times more than 'SAE bracket history' respectively. In case of 'Sample history' with the average stress of $-4{\times}10^4$ to $4{\times}10^4$ MPa and the amplitude stress 0 to $8{\times}10^4$ MPa, the possibility of maximum damage becomes 3%. This stress state can be shown with 5 or 6 times more than the damage possibility of 'SAE Bracket history' or 'SAE transmission'. This study result is applied with the design of upper arm and it can be useful at predicting prevention and durability against its damage.

A Pilot Study on Lee Gyu-Jun(李圭晙)'s Life and Thoughts (이규준(李圭晙)의 생애(生涯)와 사상적(思想的) 경향(傾向))

  • Kwon, Oh-mi;Park, Sang-young;Ahn, Sang-young;Han, Chang-huyn;Ahn, Sang-woo
    • The Journal of Korean Medical History
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    • v.22 no.1
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    • pp.7-13
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    • 2009
  • This article conducted an pilot study on Lee Gyu-Jun(李圭晙)'s life and thoughts. He championed, and is mainly based on, old annotations of ancient Confucian bibles古文 that were made in the Han漢 and Tang唐 era in Chinese history and consequently took additionally into account Zuxi朱熹's annotations on Confucian bibles. This cause big trouble to him in conservative Gyeong Shang Province(嶺南). He participated in the Confucian Religion Movement孔敎運動 and proposed constitutional monarchy as a new polity fit for changing Korean history. He closely interacted with many resistants to the Japanese rule of Korea and had a mixed perspective on Western culture, science and technology, and social system, positive or negative, contingent on cases. He made great footprints in the history of both modern Korean medicine and philosophy. Thus there is an urgent need for the overall study on Lee Gyu-Jun in every aspect.

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The Sub-history and its meaning in Independence War of Spain against Napoleonic France - Focused on Episodios nacionales and Numancia

  • Lim, Juin
    • Cross-Cultural Studies
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    • v.24
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    • pp.19-31
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    • 2011
  • This article examines the historical view of Benito $P{\acute{e}}rez$ $Gald{\acute{o}}s$ in his historical novel named "Zaragoza" and "$C{\acute{a}}novas$" by comparing with Numancia of Cervantes. In front of the national survival crisis, $Gald{\acute{o}}s$ recognizes that it is necessary that Spain should recover humanity and morality on basis of the krausist ideal. The krausists warned subjective idealism, stressing on free-will and moral conscience in a harmonious balance of rationality. Without refusing patriotism, they warned egoistic patriotism deformed by national selfishness or nationalism. Giner de los Ríos insisted on a necessity of harmonizing national inclination and universal one. $Gald{\acute{o}}s$ emphasizes that the identity of Spain is not possession of privileged class but sweat and tears of the mass of people in daily life. He represents Efemera as the ideal history on the basis of Unamuno's 'intrahistoria', by which, instead of $Luk{\acute{a}}cs^{\prime}$ progressive history, we can peep into a historical poetics of human free nature and vividness of discontinuous and endless shifting. According to the sub-history, we come to the conclusion that $Gald{\acute{o}}s$ and Cervantes would lay emphasis on sub-history, aiming to essence of Spanish soul originated from national landscape and people's daily life.