Study on Multi-Field Coupled Evolution Mechanism of Laser Irradiated 40Cr Steel Quenching Process Based on Phase Change Induced Plasticity

Chang Li,Hexin Gao,Xinxue Chen,Zhaotai Liu,Xing Han 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

40Cr is essential to steel for the manufacture of hardened gears, and optimizing its laser quenching process will be of greatsignificance for gear wear and life extension. However, the complete reliance on the experimental trial-and-error approachdoes not effectively reveal the mechanism of the evolution of the laser quenching process in disk laser. Numerical simulationprovides an effective way to obtain the transient evolution of the laser quenching process. In this paper, the temperaturechanges physical parameters of the quenched material are calculated based on the CALPHAD method. Establish a thermoelastic–plastic multi-field coupling model for the laser hardening process of the disk laser 40Cr gear steel. Perform thenumerical calculations on the transient temperature, martensite phase fraction, and the transformation-induced plasticitystress evolution of the 40Cr laser hardening process. Focus on the mechanism of the mutual coupling between phase changebehavior and plastic strain. Calculations show that there is heat accumulation during quenching, with a peak temperatureof 1448 K. Plastic stress has a “hump” distribution, with a peak value of 834 MPa, which is 1.25 mm from the center ofthe focal point. The experimental analyses of the 40Cr gear steel quenching microstructure and hardness distribution stateby the Axioskop2 scanning electron microscope, the KEYENCE VH-Z100R super depth of field 3D microscope, and theQ10M microhardness tester reveal the mechanical behavior of the material and the phase hardening law during the quenchingprocess. That provided an essential theoretical basis for effective prediction on quenching residual stress and optimizingindustrial production parameters.

Effects on Human Life of Volcanic Eruptions

Chen, Chang-Hwa 한국방재학회 2012 한국방재학회 학술발표대회논문집 Vol.11 No.-

The volcanic activity will result in geological hazards which clearly depend on a variety of factors, for example the distance from the volcanic vents, population in area, volcanic eruption types and sizes. The main causes of the geological hazards (special human life) are pyroclastic flows, debris avalanches, tsunami and starvation during volcanic eruptions. The records of human life lost in eruptions prior to AD1600 is not enough sufficient. Then, the post-AD1600 records might be discussed. On this basis, number of deaths caused by direct and indirect volcanic eruptions was summarized in less 300,000 in last 400 years. Comparison with those by earthquakes in last 10 years (2001-2011), number of life lost is upper to 800,000 (USGS data), which is much higher than those by volcanic eruptions. However, if we consider the super-eruptions (VEI>7) in geological time scale, they should effect the global climate changes. Our data showed that the bottle neck of human evolution probably related with the results of super-eruptions. The highly volcanic risk in Korea could be from dispersion of volcanic ash. The flights from Korea to northern America shall fly over the volcanic ash cloud in central and northern Japan. The civil aviation safety would be paid more attention.

비부비동 반전성 유두종의 전산화 단층촬영상과 자기공명영상의 분석

배창훈 ( Chang Hoon Bai ),서영중 ( Young Jung Seo ),이석춘 ( Seok Choon Lee ),천승민 ( Seung Min Chen ),백운회 ( Un Hoi Baek ),정은채 ( Eun Chae Jung ),송시연 ( Si Youn Song ),김용대 ( Yong Dae Kim ) 영남대학교 기초/임상의학연구소 2005 Yeungnam University Journal of Medicine Vol.22 No.2

Background: Computed tomography (CT) is commonly used to evaluate the degree of sinus involvement in cases of inverted papilloma (IP). However, CT cannot differentiate tumor from adjacent inflammatory mucosa or retained secretions. By contrast, magnetic resonance imaging (MRI) has been reported to be useful in distinguishing IP from paranasal sinusitis. This study investigated whether preoperative assessment with MRI and CT accurately predict the extent of IP.1) Materials and methods: CT and MRI were retrospectively reviewed in 9 cases of IP. Patients were categorized into stages based on CT and MRI findings, according to the staging system proposed by Krouse. The involvement of IP in each sinus was also assessed. Results: Differentiation of IP from inflammatory disease may be more successful in routine cases where the inflammatory mucosa has low signal intensity on T1-weighted images and very high signal intensity on T2-weighted images. CT imaging could not differentiate tumor from adjacent inflammatory mucosa or retained secretions. Conclusion: Preoperative MRI of IP can predict the location and extent of the tumor involvement in the paranasal sinuses and sometimes predicts malignant changes.

Impact of urban warming on earlier spring flowering in Korea

Jeong, Jee‐,Hoon,Ho, Chang‐,Hoi,Linderholm, Hans W.,Jeong, Su‐,Jong,Chen, Deliang,Choi, Yong‐,Sang John Wiley Sons, Ltd. 2011 International journal of climatology Vol.31 No.10

<P><B>Abstract</B></P><P>Using long‐term (1954–2004) observations of four selected species in South Korea: goldenbell (<I>Forsythia koreana</I>), azalea (<I>Rhododendron mucronulatum</I>), cherry (<I>Prunus yedoensis</I>), and peach (<I>Prunus persica</I>), the impact of urban warming on spring flowering was investigated. Trends of early spring temperatures and first‐flowering dates (FFDs) of the four plants were cross‐compared among nine differently urbanized cities. It was clearly observed that urban warming has led to an advance in the timing of first‐flowering of several days to weeks during recent decades, while the intrinsic physiology of plants to sense thermal energy has not been changed. The degree of advancement of the FFD was observed to be roughly proportional to degree of urbanization. Moreover, the sensitivity of the FFD to urban warming was estimated to be higher for the shrub species (−9.07 and −6.64 days °C<SUP>−1</SUP> for goldenbell and azalea, respectively) than the tree species (−2.46 and −2.90 days °C<SUP>−1</SUP> for peach and cherry, respectively). Our results suggest that the impact of urban warming should be considered as an influential factor which drives changes in the regional natural environment, especially in regions of rapid urbanization. Copyright © 2010 Royal Meteorological Society</P>

Functional Characterization of Mammary Gland of Holstein Cows under Humid Tropical Summer Climates

Lu, C.H.,Chang, C.J.,Lee, P.N.,Wu, C.P.,Chen, M.T.,Zhao, X. Asian Australasian Association of Animal Productio 2003 Animal Bioscience Vol.16 No.7

Physiological parameters were measured on six primiparous, non-pregnant Holstein cows prior to peak lactation over a 3-month summer season in southwestern Taiwan. The objectives were to characterize heat stress-induced change in functionality of mammary gland under natural climates of tropical summer and to establish physiological indices applicable to this environment in referring to this change. Environmental and physiological readings, milk and blood samples were taken at 15:00 h biweekly for totally five time points during the study. Climate readings showed that the afternoon humidex value reached the highest (53.5) around mid summer. Rectal temperature of cows taken simultaneously varied between $38.26^{\circ}C$ and $40.02^{\circ}C$ in parallel to humidex. Milk production declined drastically from 29.2 to 22.2 kg/d the first month entering summer but leveled up at end of the summer season suggesting effects exerted by heat stress rather than stages of lactation. Lactose content decreased linearly (p<0.05) with times in summer, from 4.69 to 4.38%. On the other hand, activity of N-acetylglucosaminidase (NAGase) in milk increased linearly to over two folds (p<0.05) during the same intervals. Elevations of fractional constituent of BSA in whey protein and serum cortisol level were also noticed in the course. Measurement of arteriovenous concentration (A-V) difference across the mammary gland demonstrated net uptake of glucose and net release of urea throughout the study period. The amount of urea released from mammary gland increased (p<0.05) progressively from 1.54 to 7.76 mg/dl during summer. It is concluded that gradual regression of mammary gland occurred along the humid tropical summer season. This regression is likely initiated through elevation of body temperature, which is irreversible above certain point. The increased release of urea from mammary gland during heat stress suggests its potential role as an early indicator of suboptimal mammary function.

A Proteomic Analysis of Leaf Responses to Enhanced Ultraviolet-B Radiation in Two Rice (Oryza sativa L.) Cultivars Differing in UV Sensitivity

Xing-Chun Wu,Chang-Xun Fang,Jin-Yang Chen,Qing-Shui Wang,Ting Chen,Wen-Xiong Lin,Zhong-Liang Huang 한국식물학회 2011 Journal of Plant Biology Vol.54 No.4

To determine the proteomic response to UV irradiation, two cultivars, i.e., Lemont (UV tolerant) and Dular (UV sensitive), were exposed to natural and enhanced ultraviolet-B (UV-B) irradiation for 1, 7, and 14 days, and two-dimensional gel electrophoresis in combination with mass spectrometry (MS) and bioinformatics were used to compare the different proteomic responses in the leaves of the two cultivars. Thirty-nine proteins were up- or downregulated following the UV-B treatments. Among them, 30 increased or decreased more than 1.5-fold in abundance. They were further tested by using matrix-assisted laser desorption/ionization time of flight MS and performed a database search. Twentyfour proteins were thus identified. These identified proteins were mostly upregulated in Lemont, whereas only 14 of them upregulated in Dular. Nine proteins involved in glycometabolism and fatty acid metabolisms, signal transduction, and protein synthesis and folding in Dular were not changed. These results suggest that there was a complex regulative mechanism on the proteomes in rice leaves upon UV-B exposure.

1980년대 이후 대만 음식(cuisine)의 형성

마이클 사오(Hsin-Huang Michael Hsiao),메이창(May Yu-Hsin Chang),메이-후이첸(Mei-Hui Chen),권정화(번역자) 서울대학교 아시아연구소 2015 아시아리뷰 Vol.5 No.1

대만 음식의 출현은 대만의 민주화 과정과 1980년대 이래 국가 정체성의 성장과 관련이 깊다. 어떠한 측면에서 대만 음식의 형성은 중국 본토의 장저(江浙) 음식, 쓰촨(四川) 음식, 광둥(廣東) 음식 체계가 우세한 가운데 대만 내 두 개의 주요 민족음식, 즉 민난과 학카 음식이 자유화된 것으로 볼 수도 있다. 한족의 음식으로 알려진 민난과 학카 음식이 대만을 대표하는 요리로 급부상하게 된 것이다. 그러나 한족이 아닌 원주민 음식은 여전히 대만 음식으로 통합되지 않고 있는 점 또한 주목해야 한다. 이 글은 대만 음식의 부상이 정치적 변환과 문화적 변화를 뛰어넘는 사회적 산물이라는 점에 주목하고 있다. 민난과 학카 민족 음식의 소비는 가정의 범주를 넘어 레스토랑에서 볼 수 있는 상품화된 ‘요리’로서 빠르게 자리잡고 있다. 이 글은 민난과 학카 민족 음식의 ‘요리화’와 ‘대중화’의 특징과 변화를 설명하고자 한다. 또한 민난, 학카 음식이 어떻게 ‘표현’되고, 어떠한 ‘위치’에 있고, 대만 국가 음식으로써 ‘어느 정도’ 역할을 하는지도 주목한다. 결론에서는 민주주의, 민족성, 국가정체성이 어떻게 연관되어 있고, 이들의 관계가 대만의 현대 음식에 어떻게 반영되어 있는지를 살펴본다. The emergence of Taiwanese cuisine has much to do with the democratization process and the growth of Taiwan national identity since the 1980s. In one way, the making of Taiwanese cuisine can be seen as the liberalization of two major ethnic foods, Mainan and Hakka, from the dominance of Mainland China’s provincial food customs such as that of Jiang-Zhe, Szechuan, and Guandong. The two ethnic Han food of Minnan and Hakka have thus been ungraded to constitute the new core components of the rising Taiwan’s national cuisine. It is equally important to note that, however, the non-Han aborigine food has not been considered as an integral part of Taiwanese cuisine. This paper intends to argue that the rise of Taiwanese cuisine is the direct social product of the above political transformation and cultural change. The Minnan and Hakka ethnic foods have since then been rapidly commercialized to become the recognized “cuisine” popularly served in restaurants beyond household consumption. The rise of “cuisinization” as well as “popularization” of ethnic Mainnan and Hakka foods will then be discussed in this paper by identifying the main features and changes of each of the ethnic food. Special attention is also paid to how Minnan and Hakka food are being “presented,” “positioned” and “weighted” in the constitution of “Taiwanese national cuisine.”Finally, in the conclusion, the interplay of democracy, ethnicity and national identity and its impact on Taiwan’s contemporary foodscape will be highlighted.

비부비동 반정성 유두종의 전산화 단층촬영상과 자기공명영상의 분석

배창훈,서영중,이석춘,천승민,백운희,정은채,송시연,김용대 영남대학교 의과대학 2005 Yeungnam University Journal of Medicine Vol.22 No.2

Background: Computed tomography (CT) is commonly used to evaluate the degree of sinus involvement in case of inverted papilloma (IP). However, CT cannot differentiate tumor from adjacent inflammatory mucosa or retained secretions. By contrast, magnetic resonance imaging (MRI) has been reported to be useful in distinguishing IP from paranasal sinusitis. This study investigated whether preoperative assessment with MRI and CT accurately predict the extent of IP. Materials and methods: CT and MRI were retrospectively reviewed in 9 case of IP. Patients were categorized into staged based on CT and MRI findings according to the staging system proposed by Krouse. The involvement of IP in each sinus was also assessed. Results: Differentiation of IP from inflammatory disease may be more successful in routine case where the inflammatory mucosa has low signal intensity on T1-weighted images and very high signal intensity on T2-weighted images. CT imaging could not differentiate tumor from adjacent inflammatory mucosa or retained secretions. Conclusion: Preoperative MRI of IP can predict the location and extent of the tumor involvement in the paranasal sinuses and sometimes predicts malignant changes.

小麥의 稈長 遺傳에 관한 연구

曺章煥,吳正行,蔡濟天,鄭吉雄,金鳳九 단국대학교 1992 論文集 Vol.26 No.-

This study has been conducted to investigate the genetic and ecological variation of wheat culm length measured from those plants grown at greenhouse. The results are as following. 1. The clum length of the winter wheat was higest under 12hrs daylength, while that of the spring wheat was highest under 8hrs daylength. Standard errors of culm length was larger under 12 and 8hrs daylength than that of 24hrs daylength condition. 2. The culm length was shortest under the 24hrs daylength compare to under 12 or 8hrs while it was highest under 12hrs. Short and medium culm length varieties were photo-insensitive but those of long culm length were photo-sensitive. 3. There are many types of varietal differences for the culm length under the daylength conditions. Highest culm length group under 12 and 8hrs conditions was classified. The semi-dwarf varieties that did not change their plant heights under i and 12hrs conditions were Hira, Yecora Resel, Sava, Sturdy, Saric 70, Sekidorisai 66etc. 4. Varietal difference of culm elongation was noticed between 8hrs and 12hrs daylength condition. On the basis of the evidences obtained from this experiment, it may be concluded that the genetic studies related to culm length should be carried out under the most favorable conditions for culm elongation. 5. Correlation coefficients estimated between culm length and heading or maturity were negative but insignificant, but their correlations were highly significant between photo treatments. 6. Culm length of F_1 was intermediate to the range of F_2 population which seems to be distributed normally. In this regard the gene involved with culm length seemingly inherit additively. Statistical analysis for the involved genes for culm length suggested 2 genes for the semidwarf variety Robin #2.

디지탈 교환기 시스템용 결함 허용 시스템에 관한 연구

김현욱,이동욱,한창호,문태수,이광배,박석천 明知大學校 産業技術硏究所 1994 産業技術硏究所論文集 Vol.13 No.-

A Fault tolerant system is one that can continue to correctly perform its specified tasks in the presence of hardware failures and software errors. This paper discribes hardware redundancy of fault tolerant methods used in the present digital switching systems, and proposes several new fault tolerant methods for digital switching systems. In addition, are compared and analyzed reliabilities between thr present and the new facult tolerant methods.