Austenite Grain Growth Behavior of 30BF Steel Before Rough Rolling

Yong‑feng Chen,Jian‑bo Xie,Yan‑xin Wu,Jian‑xun Fu 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.4

To investigate the eff ect of heat treatment on the grain size of austenite in 30BF steel, the comparisons of the morphologiesand sizes of austenite grains between heating samples were made with a high-temperature electric resistance furnace, andthe austenite growth models were built with method of mathematics. The results show that most grains in original specimenwith the sizes below 70 μm uniformly distributed. At a heating rate ( v ) of 10 °C/s, the grain size ( d ) value under a certain time( t ) increased by 60–100 μm with raising temperature ( T ) from 850 to 1100 °C, whereas the d value under a certain T merelyincreased by 70–120 μm with raising time to 60 min. Under v = 0.1 °C/s, T = 850 °C, and t = 0 s, the occupied ratio of grainswith sizes of 40–50 μm was 0.165, whereas at 900 °C, the occupied ratio was 0.125. The evolutions of ln (d5.8− d5.80 ) with1/ T were in negative linear correlations, whereas the ln (d5.8− d5.80 ) with ln t were in positive linear correlations. To sum up,the grain growth behavior of steel was elucidated.

甘川流域 地下水系 水理地質學的 硏究

金永琪,金又寬 경북대학교 교육대학원 1970 논문집 Vol.1 No.-

The area around Nak dong River Basin may be divided into two hydrogeologic provinces on the basis of hydrolic boundary analysis. The Hydrogeologic provinces are named as Naktong and Silra hydrogeologic provinces by the writers. The Naktong bydrogeologic province locates at the west side of Naktong River, whereas Silra hydrogeologic povince locates at the east side of Naktong River. The Naktong hydrogeologic provinces consists of uppoer-Naktorn River, Naesuing cheon, Songya and Michean, Yungcheon. Namcheon, Kamcheon, Backcheon, Hecheon, Hwangcheon, and Namkang Ground Water systems. The Siltra hydrogeologics province consist of Banbyencheon, Micheon, Uicheon, Suensan, Kumhogang, Changnyeng, Milyangcheon,and under-Naktong river Ground water systems. This paper entitled "The Hydrogeoligic Study of Kamcheon River Basin Groundwater System." emphasizes the ground water movement within Kamcheon River Basin Ground Water System. The studied system consists hydrogeologically of the consolidated rocks and unconsolidated deposits. the groundwater within the consolidated rocks (Granite and gneissose rock) is nglible for us to use it. Accordingly, The writers mainly study groundwater within the unconsolidated deposits. The unconsolidated deposits consists in some detail of Sedentary and Allvuium deposits. The coefficient of permeability in the Sedentary deposits is so neglible that the writers again exclude it from groundwater category in the system. THe writers finally limit their detailed study to the Alluvium deposits. The boring data from Aquifier and detailed geology within the Alluvium deposit were carefully discussed and studied at the standpoint of ground water movement and concluded as the followings: 1) The seven ground water areas within Kamcheon River Bsin groundwater system form ground water dom, groundwater, and groun water basin. However, the groundwater over the whole system is considered to be closer to Arterian water rather than ground water. 2) The speed of groundwater flow range 1.4㎝/H to 190.57㎝/H. The average would be 25㎝/H. The ground water flows so slowly that it would take considerable time before the water gathers ofter discharge.

P型 α-多孔 SiC. 的光致發光光潽硏究

이기환,김영유,두영뢰,우배매 公州大學校 基礎科學硏究所 1998 自然科學硏究 Vol.7 No.-

The photoluminescence (PL) spectra from p-type a-porous silicon carbides prepared under UV photo-assisted process and under dark-current condition are investigated in detail. Emission bands with peak energies of 2.35, 2.50, 2.70, and 3.43 are resolved. The PL stability in tune and the PL difference arising from different tuning excitation energies are studied. It is found that the PL spectra of the a-porous silicon carbide depend strongly on the preparation conditions for electrochemical etching. The PL spectrum of the sample prepared under photo-assisted process has an enhancement on the lower-energy side of the emission; on the contray, another one under dark-current condition has an enhancement at the higher energy side, and the former stability is better than the latter one, and the latter PL intensity decreases with the increase of the time in the air. The reasons about these differences are discussed.

한국인 및 중국 한족 정신분열병 환자의 5-HT2A 수용체 유전자 -1438A/G 다형성

이장호,이광철,이승부,오용인,최영근,조아랑,정주호,장환일 大韓神經精神醫學會 2005 신경정신의학 Vol.44 No.1

Objectives : The purpose of the present study was to investigate the association between -1438A/G polymorphism of 5-HT2A receptor gene and schizophrenia in Korean and Han Chinese population. Methods : A sample of 184 Korean patients with schizophrenia and 96 Korean healthy normal controls and 96 Han Chinese patients with schizophrenia and 96 Han-Chinese healthy normal controls were genotyped for a single nucleotide polymorphism with in 5-HT2A receptor gene (promoter region, A-1438G) by Msp I Resthction Fragment Length Polymorphism (RFLP). Results : There was no difference in allelic frequencies and genotype frequencies of -1438A/G polymorphism between Korean schizophrenics and controls (p=0.13) and Han Chinese schizophrenics and controls (p=0.40). Also, -1438A/G Poly-morphism did not show ethnical difference between Korean and Han Chinese controls. The Scale for the Assessment of Negative Symptoms (SANS) scores showed no significant differences between genotypes of -1438A/G polymorphism in both of Korean and Han Chinese schizophrenics. Conclusion : These results suggest that -1438A/G polymorphism of the 5-HT2A receptor gene is not causally related to the development of schizophrenia in Korean and Han Chinese population, and there no ethnic difference between Korean and Han Chinese population.

Macrophages Promote Coal Tar Pitch Extract-induced Tumorigenesis of BEAS-2B Cells and Tumor Metastasis in Nude Mice Mediated by AP-1

Zhang, Peng,Jin, Yue-Fei,Zhang, Qiao,Wu, Yi-Ming,Wu, Wei-Dong,Yao, Wu,Wu, Yong-Jun,Li, Zhi-Tao,Zhao, Yong,Liu, Yu,Feng, Fei-Fei Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.12

Background: We sought to evaluate the role of tumor associated macrophages (TAMs) on the promotion of coal tar pitch extract (CTPE)-induced tumorigenesis of human bronchial epithelial cells (BEAS-2B) and tumor metastasis in nude mice, and related mechanisms. Materials and Methods: BEAS-2B cells were first treated with 2.4 mg/mL CTPE for 72 hours. After removal of CTPE, the cells were continuously cultured and passaged using trypsin-EDTA. THP-1 cells were used as macrophage-like cells. BEAS-2B cells under different conditions (n=6/group) were injected into the back necks of nude mice, and alterations of tumor xenograft growth, indicative of tumorigenicity, and tumor metastasis were determined. Pathological changes (tumor nests and microvascular lesions) of HE-stained tumor tissues were also evaluated. The expression of AP-1(c-Jun) in xenografts and metastatic tumors was determined using immunohistochemistry. Results: Tumor size and weight in nude mice transplanted with the mixture of CTPE-induced passage 30 BEAS-2B and THP-1 cells (2:1) were increased compared to those from the CTPE-treated BEAS-2B cells at passage 30 alone at different observation time points. Tumor metastasis to lymph nodes and liver was only detected after transplantation of a mixture the two kinds of cells. The numbers of tumor nests and microvascular lesions, and the expression levels of AP-1 (c-Jun) in tumors from the mixture of two kinds of cells were increased apparently in contrast to those in tumor from the CTPE-treated BEAS-2B cells of passage 30 alone. In addition, there was positive correlation between AP-1 (c-Jun) expression level and the number of microvascular lesions, or between AP-1 (c-Jun) expression level and tumor metastasis in these two groups. Conclusions: TAMs not only facilitate tumorigenesis transformation of CTPE-induced BEAS-2B cells, but also promote tumor growth, angiogenesis and metastasis in nude mice in vivo, which may be mediated by AP-1.

An Experimental and Computational Study of Environmental Loads on a Fixed Substructure for Offshore Wind Turnbine

Wu-Joan Kim(김우전),Yeon-Seok Park(박연석),Chang-Yong Song(송창용),Jae-Hoon Yoo(유재훈),Dae-Yong Lee(이대용) 한국해양환경·에너지학회 2013 한국해양환경공학회 학술대회논문집 Vol.2013 No.11

본 논문에서는 해상풍력터빈 설치를 위한 지지구조물에 작용하는 파도와 조류에 의한 환경하중에 대하여 조사하였다. 다중 파일로 이루어진 고정식 해상풍력 지지구조물에 대하여 조파수조 시험과 CFD 유동해석이 수행되었다. 먼저 하부구조물 모형에 대하여 조파수조에서 파랑하중을 계측하였다. 또한 수치조파수조를 이용한 CFD 유동해석과 구조물의 동적구조응답해석을 위한 FEM 해석이 이루어졌다. 다음으로 모형 구조물을 예인수조에서 끌면서 조류하중을 계측하였다. 그리고 해저면에 형성되는 조류 점성경계층에 의해 구조물의 다리와 해저면이 만나는 지점에서 발생하는 horse-shoe 보오텍스에 대한 수치모사와 그로 인한 해저면 침식 현상인 scouring에 대한 시뮬레이션을 수행하였다. Environmental loads acting on an offshore structure for wind turbine by waves and current flow were investigated. Both wave tank measurement and CFD simulation were performed with a fixed type offshore wind turbine substructure having multi-piles. In the first, measurement of wave load on the model substructure was carried out at the wave tank. CFD simulation using the numerical wave tank was also done with the design wave condition and FEM analysis for dynamic load response of substructure was calculated. Next, current load was measured by towing the model substructure in the towing tank. Finally the formation of horse-shoe vortices around the juncture of substructure legs and seabed, due to bottom boundary layer, and the resulting scouring phenomena were simulated.

Anti-inflammatory effects of ethanolic extracts of a Chinese herbal medicine Pteridium aquilinum on LPS-stimulated Raw264.7 cells

Yong-Xiang Wu,Hyeon-Ji Bae,Min-Jeong Kim,You-Jeong Kim,Geum-Sun Kim,Suk-Jea Bea,Jeong-Suk Kim,Ui-Sang Yun,Taewan Kim 한국식품영양과학회 2011 한국식품영양과학회 학술대회발표집 Vol.2011 No.10

Anti-obesity and anti-diabetic effects of mulberry root bark and its action mechanism

Yong-Xiang Wu,Taewan Kim 한국식품영양과학회 2014 한국식품영양과학회 학술대회발표집 Vol.2014 No.10

A GENERAL RICCI FLOW SYSTEM

Wu, Jia-Yong Korean Mathematical Society 2018 대한수학회지 Vol.55 No.2

In this paper, we introduce a general Ricci flow system, which is closely linked with the Ricci flow and the renormalization group flow, etc. We prove the short-time existence, the entropy functionals, the higher derivatives estimates and the compactness theorem for this general Ricci flow system on closed Riemannian manifolds. These basic results are useful tools to understand the singularities of this system.

Evaluation and Utilization of Xinjiang Melon (Cucumis melo ssp. melo) Germplasm Resources

Wu ming zhu,Yi hong ping,Feng jiong xin,Li jin song,Wang deng ming,Aken ya sheng,Zhang yong bing,Zhai wen qiang,Wu hai bo 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-