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Detection of Breaking Waves Using X-Band Pulse Radar in the Nearshore Region

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china Ocean Engineering 2013年第4期27卷 549-556页

作者： Y.c.Lin c.c.chang m.c.Lee H.c.chan j.m.Leu Department of Hydraulic and Ocean Engineering National Cheng-Kung University Department of Soil and Water conservation National Chung Hsing University Department of Hospitality management Taiwan Shoufu University

An X-band pulsed Doppler microwave radar has been used to determine the characteristics of breaking waves. Field experiments were conducted at the Shuang-Si estuary in the north of Taiwan in the winter of 2005. Analyses on maxima radar cross section and Doppler frequency shift are done to characterize wave breaking zones. Based on observations of breaking waves, the wave breaking zones are shown to be located at water depths of 1.8 to 2.2 m in the experimental site. In general, the results indicate that a radar system has the potential to delineate the spatial variation of breaking waves clearly and that this is sufficient to achieve a measurement operation for near-shore air-sea interaction events.

关键词： radar Doppler effect wave breaking coastal zone

A Dimension-Reduction Interval Analysis method for Uncertain Problems

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computer modeling in Engineering & Sciences 2017年第3期113卷 239-259页

作者： j.c.Tang c.m.Fu State Key Laboratory of Advanced Design and manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha City410082P.R.China college of mechanical Engineering University of South ChinaHengyang 421001P.R.China

In this paper,an efficient interval analysis method called dimension-reduction interval analysis(DRIA)method is proposed to calculate the bounds of response functions with interval variables,which provides a kind of solution method for uncertainty analysis problems of complex structures and ***,multi-dimensional function is transformed into multiple one-dimensional functions by extending dimension reduction method to the interval analysis ***,all the one-dimensional functions are transformed to standard quadratic form by second order Taylor expansion *** a result,the multi-dimensional function is approximately represented by the functions that each interval variable occurs once,and interval power arithmetic can be used to efficiently calculate the bounds of response functions in restricted ***,three numerical examples and an engineering application are investigated to demonstrate the validity of the proposed method.

关键词： Interval uncertainty interval analysis dimension-reduction method over estimation

Dynamic mechanical Relaxation in Bulk metallic Glasses:A Review

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journal of materials Science & Technology 2014年第6期30卷 523-545页

作者： j.c.Qiao j.m.Pelletier Université de Lyon CNRS France INSA-Lyon MATEIS UMR5510 F-69621 Villeurbanne France

metallic glasses have aroused considerable interest in the past decades because they exhibit fascinating properties. First, this article briefly outlines the mechanical, thermal properties and application of the metallic glasses. In addition, we focus on the dynamic mechanical relaxation behaviors, i.e. main （α） and secondary （β） relaxations, in metallic glasses. The mechanical relaxation behaviors are connected to the mechanical properties and physical properties in glassy materials. The main relaxation in glassy materials is related to the glass transition phenomenon and viscous flow. On the other hand, the β relaxation is linked to many fundamental issues in metallic glasses. In these materials relaxation processes are directly related to the plastic deformation mechanism. The mechanical relaxations, particularly, the β relaxation provides an excellent opportunity to design metallic glasses with desired physical and mechanical properties. We demonstrate the universal characteristics of main relaxation in metallic glasses. The phenomenological models and the physical theories are introduced to describe the main relaxation in metallic glasses. In parallel, we show the dependence of the α. and β relaxations on the thermal treatments in metallic glasses. Finally, we analyze the correlation between the atomic mobility and the thermo-mechanical treatments in metallic glasses. On the one hand, the atomic mobility in metallic glasses is reduced by physical aging or crystallization. On the other hand, the atomic mobility in metallic glass is enhanced by deformation （i.e. compression and cold rolling）. Importantly, to analyze the atomic mobility in amorphous materials, a physical theory is introduced. This model invokes the concept of quasi-point defects, which correspond to the density fluctuations in the glassy materials.

关键词： metallic glasses mechanical properties main relaxation Secondary relaxation Physical analysis

State of the Art on micromilling of materials,a Review

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journal of materials Science & Technology 2012年第8期28卷 673-685页

作者： m.A.cmara j.c. campos Rubio A.m. Abro j.P. Davim Department of mechanical Engineering Universidade Federal de Minas GeraisAv.Ant onio Carlos6627-Pampulha Belo Horizonte MGCEP:31.270-901Brazil Department of mechanical Engineering University of AveiroCampus Universitrio de Santiago3810-193AveiroPortugal

The trend towards miniaturization has increased dramatically over the last decade, especially within the fields concerned with bioengineering, microelectronics, and aerospace. micromillin8 is among the principal manu- facturing processes which have allowed the development of components possessing micrometric dimensions, being used to the manufacture of both forming tools and the final product. The aim of this work is to present the principal aspects related to this technology, with emphasis on the work material requirements, tool ma- terials and geometry, cutting forces and temperature, quality of the finished product, process modelling and monitoring and machine tool requirements. It can be noticed that size effect possesses a relevant role with regard to the selection of both work material （grain size） and tooling （edge radius）. Low forces and temper- ature are recorded during micromillin8, however, the specific cutting force may reach high values because of the ploughing effect observed as the uncut chip thickness is reduced. Finally, burr formation is the principal concern with regard to the quality of the finished part.

关键词： micro-milling micromachining Size effect miniaturization

Site Selective Excitation and Energy Transfer in LiKGdF_5 crystal co-doped with Er^(3+) and Tb (3+)

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journal of Rare Earths 2004年第1期22卷 22-26页

作者：尹民 Khaidukov N m Krupa j c Structure Research Laboratory Kurnakov Institute of General and Inorganic chemistry Institut de Physique Nucléaire

crystals of LiKGdF 5∶Er 3+, Tb 3+ grown by the hydrothermal synthesis technique with concentrations of 2% and 0.4% were analysed. By using site selective excitation measured at low temperature, luminescence and excitation spectra from Er 3+ and Tb 3+ ions embedded in LiKGdF 5 were clearly separated. The lifetimes of the emitting levels 4S 3/2 of Er 3+ and 5D 4 of Tb 3+ were also determined. Following the site selective spectroscopy study, the dominant energy transfer process from Tb 3+ to Er 3+ in the crystal was then investigated via transient experiments.

关键词： optics condensed matter physics energy transfer luminescence LiKGdF 5∶Er3+, Tb3+ rare earths

TRANSIENT ANALYSIS OF cOmPOSITE PLATES BY A LOcAL RADIAL BASIS FUNcTIONS-FINITE DIFFERENcE TEcHIQUE

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Acta mechanica Solida Sinica 2012年第1期25卷 22-36页

作者： c.m.c.Roque D.cunha A.j.m.Ferreira INEGI Faculdade de Engenharia da Universidade do PortoRua Dr.Roberto Frias Departamento de Engenharia mecnica Faculdade de Engenharia da Universidade do PortoRua Dr.Roberto Frias

The use of local numerical schemes,such as finite differences produces much better conditioned matrices than global collocation radial basis functions ***,finite differ-ence schemes are limited to special *** scattered points,a combination of finite differences and radial basis functions would be a possible *** this paper,we use a higher-order shear deformation plate theory and a radial basis function-finite difference technique for predicting the transient behavior of thin and thick composite *** numerical experiments on beams and composite plates,the accuracy and efficiency of this collocation technique is demonstrated.

关键词： meshless beam composite plate

Visualising data distributions with kernel density estimation and reduced chi-squared statistic

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Geoscience Frontiers 2017年第6期8卷 1247-1252页

作者： c.j.Spencer c.Yakymchuk m.Ghaznavi Earth Dynamics Research Group The Institute of Geoscience ResearchDepartment of Applied GeologyCurtin UniversityPerthAustralia Department of Earth and Environmental Sciences University of WaterlooWaterlooCanada David R.cheriton School of computer Science University of WaterlooWaterlooCanada

The application of frequency distribution statistics to data provides objective means to assess the nature of the data distribution and viability of numerical models that are used to visualize and interpret *** commonly used tools are the kernel density estimation and reduced chi-squared statistic used in combination with a weighted *** to the wide applicability of these tools,we present a java-based computer application called KDX to facilitate the visualization of data and the utilization of these numerical tools.

关键词： Data visualisation Kernel density estimation Reduced chi-squared statistic mean square weighted deviation Geostatistics

Hot cracking in AZ31 and AZ61 magnesium Alloy

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journal of materials Science & Technology 2011年第7期27卷 633-640页

作者： c.j. Huang c.m. cheng c.P. chou F.H. chen Department of mechanical Engineering National Chiao Tung University Hsinchu 300 Taiwan China Department of Industrial Education National Taiwan Normal University Taipei 106 Taiwan China

This paper examined the impact of the number of thermal cycles and augmented strain on hot cracking in AZ31 and AZ61 magnesium alloy. Statistical analyses were performed. Following observation using a scanning electron microscope （SEm）, an energy dispersive spectrometer （EDS） was used for component analysis. Results showed that Al content in magnesium alloy has an effect on hot cracking susceptibility. In addition, the nonequilibrium solidification process produced segregation in Al content, causing higher liquid mg-alloy rich Al content at grain boundaries, and resulting into liquefied grain boundaries of partially melted zone （PmZ）. In summary, under multiple thermal cycles AZ61 produced serious liquation cracking. AZ61 has higher （6 wt%） Al content and produced much liquefied mg17Al12 at grain boundaries under multiple thermal cycles. The liquefied mg17Al12 were pulled apart and hot cracks formed at weld metal HAZ due to the augmented strain. Since AZ31 had half the Al content of AZ61, its hot-cracking susceptibility was lower than AZ61. In addition, AZ61 showed longer total crack length （TcL） in one thermal cycle compared to that in three thermal cycles. This phenomenon was possibly due to high-temperature gasification of Al during the welding process, which resulted in lower overall Al content. consequently, shorter hot cracks exhibited in three thermal cycles. It was found the Al content of AZ31 and AZ61 can be used to assess the hot-cracking susceptibility.

关键词： Varestraint test Thermal cycles Hot-cracking susceptibility Gas tungsten arc welding (GTAW) AZ31 AZ61

Propylthiouracyl-induced severe liver toxicity:An indication for alanine aminotransferase monitoring?

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World journal of Gastroenterology 2006年第38期12卷 6232-6234页

作者： m Benyounes c Sempoux c Daumerie j Rahier AP Geubel Departments of Gastroenterology Endocrinology and Pathology St Luc University Hospital Université Catholique de Louvain Brussels 1200 Belgium

Propylthiouracyl (PTU)-related liver toxicity is likely to oc- cur in about 1% of treated patients. In case of acute or subacute hepatitis, liver failure may occur in about one third. We report two further cases of PTU-induced sub- acute hepatitis, in whom the delay between occurrence of liver damage after the initiation of treatment, the un- derestimation of its severity and the delayed withdrawal of the drug were all likely responsible for liver failure. The high incidence of liver toxicity related to PTU, its potential severity and delayed occurrence after initiation of treatment are in favor of monthly alanine aminotrans- ferase monitoring, at least during the first six months of therapy.

关键词： Hepatitis Drug-induced liver toxicity Propylthiouracil Alanine aminotransferase