Enhanced Strength-Ductility Synergy in Mg-0.5 wt%Ce Alloy by hot Extrusion

Hui Yu,Yu Liu,Ya Liu,Dongliang Wang,Yuling Xu,Binan Jiang,Weili Cheng,Lixin Huang,Weineng Tang,Wei Yu 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.7

The microstructure and mechanical properties of micro-alloyed Mg-0.5 wt%Ce alloys are investigated systemically in this study. It shows that Mg-Ce binary system is very sensitive to extrusion temperature. On the one hand, the high tensile yield strength (TYS) of 343 MPa was obtained by extrusion at 250 °C mainly due to the combined effects of profuse nano-precipitation phase, grain refinement, texture strengthening and high-density dislocation; On the other hand, the excellent elongation of 30% was acquired by extrusion at 300 °C resulting from the elimination of dislocations as well as the modification of texture.

Auditors’ Responses to Organized Labor in Client Firms

Simon Yu Kit Fung,이우종,Bin Srinidhi,Lixin (Nancy) Su 서울대학교 경영연구소 2017 Seoul Journal of Business Vol.23 No.2

Using a sample of US firms for the period 2000-2011, we examine whether organized labor in audit client firms affects auditor decisions such as audit fees and going-concern qualifications. We find that labor unionization is associated with higher audit fees and a higher likelihood of going-concern qualifications but shorter audit report lags, and the results on audit fees are stronger in the case of strikes. These results suggest that the presence of labor union(s) in a client firm constitutes a non-trivial risk element to auditors, which cannot be mitigated by additional audit effort.

An Iris Localization Algorithm based on Morphological Processing

Kun Yu,Zeyu Xu,Lixin Xu 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.3

To improve the speed of iris localization, an iris localization algorithm based on the morphological processing is proposed with fast speed. Firstly, pupil area is segmented from eye image by thresholding, to remove eyelash noise and other noises from binaryzation pupil area by morphological open operation. Then, a series of structure element of radius increasing is used to make morphological erode operation on pupil area to localize roughly the inner boundary of the iris. Finally, calculus operator is employed to accurately localize the inner and outer iris boundary. 108 iris images from CASIA (Version 1.0) iris database are used to do iris localization experiments. The localization accurate rate of the proposed algorithm, calculus operator and hough transform is 97.2%, 90.3% and 92.1% respectively. Experiment results have showed that the proposed algorithm has a high performance on speed and precision with strong robustness to the different quality iris images.

Highly stable N-doped carbon dots as the sensitive probe for the detection of Fe3+

Zhao Youjun,Yu Lixin,Deng Yakun,Peng Kangliang,Huang Shuai 한국물리학회 2023 Current Applied Physics Vol.50 No.-

The nitrogen-doped carbon dots (NCDs) are facilely fabricated by a one-step hydrothermal strategy using citric acid and o-phenylenediamine as start ingredient. The as-synthesized NCDs with a high quantum yield of 38.63% at 370 nm excitation maintain significant fluorescence stability in various complex environments, indicating that NCDs have the possibility of application in harsh environments. Moreover, after adding the Fe3+ to this as-synthesized NCDs, the emission intensity at 446 nm is remarkably reduced and exhibits line-dependent relationship in the range of 0.5–90 μM with a detection limit of 0.37 μM. Meanwhile, the fluorescence lifetime and absorption characteristics are compared respectively, and Stern-Volmer is calculated. These results illustrate that the quenched fluorescence is attributed to the synergistic effect of internal filtration effect (IFE) and static quenching. Moreover, this carbon-based sensing material has elevated efficiency in detecting Fe3+ in practical samples, implying that the sensing probe provides a fast and accurate new technique for the detection of Fe3+.

VO-OV语序与相关语法参项组配研究分析

金立?(Jin Lixin),于秀金(Yu Xiujin) 계명대학교 국제학연구소 2011 국제학논총 Vol.16 No.-

This paper provides a brief review for the research into VO-OV word order and its correlated pairs of grammatical elements in linguistic typology. The generative scholars usually take a derivation approach to explaining language linear rules and universal word order, but problems still remain in cross-linguistic grammatical element movement. The typological researchers represented by Dryer put forward the Branching Direction Theory (BDT) to explain the word order of pairs of grammatical elements correlated with VO-OV, but BDT fails to expound why the order of verb, manner adverb, plural word and N" correlate with VO-OV, while that of adjective (or numeral) and noun un-correlates with VO-OV. The Constitute Recognized Domain (CRD) by Hawkins is also proved not to be the inevitable factor in the correlation between the word order of pairs of grammatical elements and VO-OV. This paper holds that left-right branching direction, strategies of structurally optimal combination and other functional factors contribute together to the correlation and un-correlation of the word order of pairs of grammatical elements with VO-OV.

EFFECT OF GRAPHITE PRECURSOR ON OXIDATION DEGREE, HYDROPHILICITY AND MICROSTRUCTURE OF GRAPHENE OXIDE

XUEBING HU,LIXIN SONG,YUN YU,JIANER ZHOU 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.3

Graphene oxide (GO) has attracted much attention as a derivative of graphene. In addition, itappears to have many unique physicochemical properties and has been investigated widely inmany areas. Herein, we prepare GOs using °ake graphite (FG), expandable graphite (EG) andmicrocrystalline graphite (MG) as graphite precursors by the modi¯ed Hummers method. According to the X-ray di®raction (XRD), Fourier transform infrared spectroscopy, X-rayphotoelectron spectroscopy (XPS) and Raman spectroscopy, we characterize the component, thefunctional group, the chemical state of the element and the structural disorder of the obtainedGOs to reveal their oxidation degree. Besides, we evaluate the hydrophilicity of the obtained GOswith the water contact angle, and observe their microstructures by transmission electron mi-croscopy (TEM). We ¯nd that the GO prepared with EG has a higher-degree oxidation andbetter hydrophilicity, and it will be exfoliated easily and forms a monolayer or quasi-monolayerstructure. Finally, based on the structural characteristic of graphite precursor, we build theintercalation and oxidation model to illuminate the phenomenon.

STABILITY OF IMPULSIVE CELLULAR NEURAL NETWORKS WITH TIME-VARYING DELAYS

Lijuan Zhang,Lixin Yu 한국전산응용수학회 2011 Journal of applied mathematics & informatics Vol.29 No.5

This paper demonstrates that there is a unique exponentially stable equilibrium state of a class of impulsive cellular neural network with delays. The analysis exploits M-matrix theory and generalized comparison principle to derive some easily verifiable suffcient conditions for the global exponential stability of the equilibrium state. The results extend and improve earlier publications. An example with its simulation is given for illustration of theoretical results.

STABILITY OF IMPULSIVE CELLULAR NEURAL NETWORKS WITH TIME-VARYING DELAYS

Zhang, Lijuan,Yu, Lixin The Korean Society for Computational and Applied M 2011 Journal of applied mathematics & informatics Vol.29 No.5

This paper demonstrates that there is a unique exponentially stable equilibrium state of a class of impulsive cellular neural network with delays. The analysis exploits M-matrix theory and generalized comparison principle to derive some easily verifiable sufficient conditions for the global exponential stability of the equilibrium state. The results extend and improve earlier publications. An example with its simulation is given for illustration of theoretical results.

Pantropical climate interactions

Cai, Wenju,Wu, Lixin,Lengaigne, Matthieu,Li, Tim,McGregor, Shayne,Kug, Jong-Seong,Yu, Jin-Yi,Stuecker, Malte F.,Santoso, Agus,Li, Xichen,Ham, Yoo-Geun,Chikamoto, Yoshimitsu,Ng, Benjamin,McPhaden, Mich American Association for the Advancement of Scienc 2019 Science Vol.363 No.6430

<P><B>Tropical interconnections</B></P><P>The El Niño–Southern Oscillation, which originates in the tropical Pacific, affects the rest of the world's tropics by perturbing global atmospheric circulation. Less appreciated than this influence is how the tropical Atlantic and Indian Oceans affect the Pacific. Cai <I>et al.</I> review what we know about these pantropical interactions, discuss possible ways of improving predictions of current climate variability, and consider how projecting future climate under different anthropogenic forcing scenarios may be improved. They argue that making progress in this field will require sustained global climate observations, climate model improvements, and theoretical advances.</P><P><I>Science</I>, this issue p. eaav4236</P><P>The El Niño–Southern Oscillation (ENSO), which originates in the Pacific, is the strongest and most well-known mode of tropical climate variability. Its reach is global, and it can force climate variations of the tropical Atlantic and Indian Oceans by perturbing the global atmospheric circulation. Less appreciated is how the tropical Atlantic and Indian Oceans affect the Pacific. Especially noteworthy is the multidecadal Atlantic warming that began in the late 1990s, because recent research suggests that it has influenced Indo-Pacific climate, the character of the ENSO cycle, and the hiatus in global surface warming. Discovery of these pantropical interactions provides a pathway forward for improving predictions of climate variability in the current climate and for refining projections of future climate under different anthropogenic forcing scenarios.</P>

Numerical investigation of the critical heat fl ux in a 5 × 5 rod bundle with multi-grid

Wei Liu,Zemin Shang,Shihao Yang,Lixin Yang,Zihao Tian,Yu Liu,Xi Chen,Qian Peng 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.5

To improve the heat transfer efficiency of the reactor fuel assembly, it is necessary to accurately calculatethe two-phase flow boiling characteristics and the critical heat flux (CHF) in the fuel assembly. In thispaper, a Eulerian two-fluid model combined with the extended wall boiling model was used tonumerically simulate the 5 5 fuel rod bundle with spacer grids (four sets of mixing vane grids and foursets of simple support grids without mixing vanes). We calculated and analyzed 11 experimental conditions under different pressure, inlet temperature, and mass flux. After comparing the CHF and thelocation of departure from the nucleate boiling obtained by the numerical simulation with the experimental results, we confirmed the reliability of computational fluid dynamic analysis for the prediction ofthe CHF of the rod bundle and the boiling characteristics of the two-phase flow. Subsequently, weanalyzed the influence of the spacer grid and mixing vanes on the void fraction, liquid temperature, andsecondary flow distribution. The research in this article provides theoretical support for the design of fuelassemblies