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Properties　of　Diamond　Film／Alumina　Composites　for　Integrated　Circuits　with　Ultra-High　Speed　and　High　Power

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Chinese Physics Letters 2004年第6期21卷 1161-1163页

作者： WANGLin-Jun XIAYi-ben FANGZhi-Jun ZHANGming-Long SHENHu-Jiang SchoolofmaterialsScienceandEngineering ShanghaiUniversityShanghai201800

We report the properties of the diamond film/alumina composites which were thought of as promising substrate materials for integrated circuits with ultra-high speed and high power. The measurement results of dielectric properties of diamond film/alumina composites show that the coating of CVD diamond films could effectively reduce the dielectric constant of the composite. Carbon ion implantation into alumina substrates prior to the diamond deposition can reduce the dielectric loss of the composite from 5 x 10-3 to 2 x 10-3, and can give the composite better frequency stability. The thermal conductivity of composites could be obviously increased by coating CVD diamond film. The composite has a dielectric constant of 6.5 and a thermal conductivity of 3.98 W/(cmK) when the thickness of diamond film is up to 100 μm.

关键词： Condensed matter: electrical magnetic and optical Surfaces interfaces and thin films

Trends of Yield and Soil Fertility in a Long-Term Wheat-maize System

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Journal of Integrative Agriculture 2014年第2期13卷 402-414页

作者： YANG Xue-yun SUN ben-hua ZHANG Shu-lan State Key Laboratory of Soil Erosion and Dryland Farming Northwest A&F University Key Laboratory of Plant Nutrition and the Agri-Environment in Northwest China Ministry of Agriculture/Northwest A&F University

The sustainability of the wheat-maize rotation is important to China＇s food security. Intensive cropping without recycling crop residues or other organic inputs results in the loss of soil organic matter （SOm） and nutrients, and is assumed to be non- sustainable. We evaluated the effects of nine different treatments on yields, nitrogen use efficiency, P and K balances, and soil fertility in a wheat-maize rotation system （1991-2010） on silt clay loam in Shaanxi, China. The treatments involved the application of recommended dose of nitrogen （N）, nitrogen and phosphorus （NP）, nitrogen and potassium （NK）, phosphorus and potassium （PK）, combined NPK, wheat or maize straw （S） with NPK （SNPK）, or dairy manure （m） with NPK （m1NPK and m2NPK）, along with an un-treated control treatment （CK）. The mean yields of wheat and maize ranged from 992 and 2 235 kg ha-1 under CK to 5 962 and 6 894 kg ha-1 under m2NPK treatment, respectively. Treatments in which either N or P was omitted （N, NK and PK） gave significantly lower crop yields than those in which both were applied. The crop yields obtained under NP, NPK and SNPK treatments were statistically identical, as were those obtained under SNPK and mNPK. However, m2NPK gave a significant higher wheat yield than NP, and mNPK gave significant higher maize yield than both NP and NPK. Wheat yields increased significantly （by 86 to 155 kg ha-1 yr-1） in treatments where NP was applied, but maize yields did not. In general, the nitrogen use efficiency of wheat was the highest under the NP and NPK treatments; for maize, it was the highest under mNPK treatment. The P balance was highly positive under mNPK treatment, increasing by 136 to 213 kg ha-1 annually. While the K balance was negative in most treatments, ranging from 31 to 217 kg ha^-1 yr^-1, levels of soil available K remained unchanged or increased over the 20 yr. SOm levels increased significantly in all treatments. Overall, the results indicated that combinations of organic manure an

关键词： wheat maize nitrogen use efficiency P balance K balance soil organic matter

Predictability and dynamics of the rapid intensification of Super Typhoon Lekima (2019)

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Frontiers of Earth Science 2022年第1期16卷 132-143页

作者： mengting XU Hong LI Jingyao LUO Hairong ben Yijie ZHU Shanghai Typhoon Institute China Meteorological AdministrationShanghai 200030China Key Laboratory of Numerical modeling for Tropical Cyclones China Meteorological AdministrationShanghai 200030China Taizhou meteorological Bureau Taizhou 318000China

This study explores the effect of the initial axisymmetric wind structure and moisture on the predictability of the peak intensity of Typhoon Lekima(2019)through a 20-member ensemble forecast using the WRF *** ensemble members are separated into Strong and Weak groups according to the maximum 10-m wind speed at 48 *** our study of Lekima(2019),the initial intensity defined by maximum 10-m wind speed is not a good predictor of the intensity *** peak intensity uncertainty is sensitive to the initial primary circulation outside the radius of maximum wind(RmW)and the initial secondary *** greater absolute angular momentum(AAm)beyond the RmW directly related to stronger primary circulation,and stronger radial inflow,Strong group is found to have larger AAm import in lowlevel,helping to spin up the *** moisture in innercore is also critical to the intensity predictability through the development of inner-core *** aggregation and merger of convection,leading to the TC intensification,is influenced by both radial advection and gradient of system-scale vortex *** sensitivity experiments are conducted to study the effect of model uncertainty in terms of model horizontal grid resolution on intensity *** horizontal grid resolution greatly impacts the predictability of Lekima’s intensity,and the finer resolution is helpful to simulate the intensification and capture the observed peak value.

关键词： tropical cyclone intensity predictability rapid intensification initial condition model resolution

International Financial market＇s Integration and modelling Returns of Risky Assets

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Journal of modern Accounting and Auditing 2012年第7期8卷 1042-1051页

作者： ben m'Barek Hassene University of Tunis Tunis Tunisia

The aim of this paper is to test the ability of conditional and unconditional capital asset pricing models （CAPms） and to explain emerging markets returns in terms of their integration into the international market. The authors use data on five developed countries and five emerging countries as well as data on the Tunis Stock Exchange （TSE） after the reforms. The results show that the correlations between emerging markets returns and developed markets returns are very low and sometimes negative. Conditional arbitrage pricing theory （APT） as well as conditional CAPm has low predictive power for emerging markets than that for developed markets. Finally, following the financial reforms, Tunisian financial markets have became more and more integrated into the international market （excess returns and unconditional beta consistent with predictions）. However, conditional APT does not accurately explain Tunisian market returns. This study confirms the unavailability of an accurate modelling technique of the TSE structure.

关键词： conditional unconditional capital asset pricing model (CAPm) conditional arbitrage pricing theory(APT) returns

Selective hydrogenation of acetylene over Pd/CeO2

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Frontiers of Chemical Science and Engineering 2020年第6期14卷 929-936页

作者： Kai Li Tengteng Lyu Junyi He ben W.L.Jang Department of Chemistry Texas A&M University CommercePO Box 3011CommerceTX 75429USA

Five hundred ppm Pd/CeO2 catalyst was prepared and evaluated in selective hydrogenation of acetylene in large excess of ethylene since ceria has been recently found to be a reasonable stand-alone catalyst for this ***/CeO2 catalyst could be activated in situ by the feed gas during reactions and the catalyst without reduction showed much better ethylene selectivity than the reduced one in the high temperature range due to the formation of oxygen vacancies by *** ethylene selectivity of〜100%was obtained in the whole reaction temperature range of 50℃-200℃ for samples calcined at temperatures of 600℃ and 800℃.This could be ascribed to the formation of PdX-Ce1-xO2-y or Pd-O-Ce surface species based on the X-ray diffiaction and X-ray photoelectron spectroscopy results,indicating the strong interaction between palladium and ceria.

关键词： selective hydrogenation acetylene Pd/CeO2 strong interaction

Influence of initial microstructure and grain size on transformation of bainite to austenite in large size forgings

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Journal of Iron and Steel Research International 2018年第5期25卷 554-562页

作者： Emna ben Fredj Hadi Ghasemi Nanesa mohammad Jahazi Jean-benoit morin Department of mechanical Engineering Ecole deTechnologie Superieure Montreal QC H3C 1K3 Canada Finkl Steel-Sorel St-Joseph-de-Sorel QC J3R 3M8 Canada

The kinetics of austenite formation in the surface and center regions of a 40 t forged ingot of a high-strength medium- carbon low-alloy steel was studied using high-resolution dilatometry. The starting microstructures from the surface or center regions had different proportions of bainite and residual austenite as well as different prior austenite grain sizes. Two heating rates representing the actual heating rates in the surface （5℃ s -1） and center regions （0.5℃ s -1） of large size forged blocks were utilized. Dilatometric curves revealed only one transformation step of austenite formation at both heating rates independent of grain size or proportion of phases. Optical microscopy, field emission gun scanning electron microscopy and X-ray diffraction were used to study microstructure evolution and confirm the results obtained by dilatometry. The kinetic parameters for austenite formation were determined from the dilatometry data by Johnson-mehl- Avrami-Kolmogorov （JmAK） equation. The JmAK coefficients were determined for each condition of the investigated steels. The calculations indicated that the nucleation and growth of austenite in the surface region were accelerated more than 10,000 times due to a significantly smaller average prior austenite grain size, stability of initial retained austenite, and accumulation of coarse carbides at the surface. The results were discussed in the framework of classical nucleation and growth theories using the kinetic parameters for austenite formation.

关键词： Large size ingot medium-carbon low-alloy steel Initial microstructure Grain size Austenite formation

mEASURES OF WEAK NONCOmPACTNESS AND FIXED POINT THEORY FOR 1-SET WEAKLY CONTRACTIVE OPERATORS ON UNBOUNDED DOmAINS

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Analysis in Theory and Applications 2011年第3期27卷 224-238页

作者： ShaoyuanXu Afif ben Amar Department of mathematics and Information TechnologyHanshan Normal UniversityChaozhou 521041 Departement de mathematiquesUniversite de Gafsa Cite Universitaire Zarrouk Faculte des Sciences de Gafsa2112 Gafsa Tunisie

The main purpose of this paper is to prove a collection of new fixed point theorems and existence theorems for the nonlinear operator equation F（x） = αx （α≥〉 1） for so-called 1-set weakly contractive operators on unbounded domains in Banach spaces. We also introduce the concept of weakly semi-closed operator at the origin and obtain a series of new fixed point theorems and the existence theorems for the nonlinear operator equation F（x） = αx （α≥1） for such class of operators. As consequences, the main results general- ize and improve the relevant results, which are obtained by O＇Regan and A. ben Amar and m. mnif in 1998 and 2009 respectively. In addition, we get the famous fixed point theorems of Leray-Schauder, Altman, Petryshyn and Rothe type in the case of weakly sequentially continuous, 1-set weakly contractive （μ-nonexpansive） and weakly semi-closed operators at the origin and their generalizations. The main condition in our results is formulated in terms of axiomatic measures of weak compactness.

关键词： measure of weak noncompactness weakly condensing and weakly nonexpansive weakly sequentially continuous weakly semi-closed at the origin fixedpoint theorem

Unraveling the dose-response puzzle of ***:A mechanistic approach

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Infectious Disease modelling 2016年第1期1卷 101-114页

作者： S.m.Ashrafur Rahman Daniel munther Aamir Fazil ben Smith Jianhong Wu Laboratory for Industrial and Applied mathematics Centre for Disease ModellingDepartment of Mathematics and StatisticsYork UniversityTorontoON M3J 1P3Canada Department of mathematics Cleveland State UniversityClevelandOH 44115United States National microbiology Laboratory Public Health Agency of CanadaGuelphON N1G 5B2Canada

Food-borne disease outbreaks caused by Listeria monocytogenes continue to impose heavy burdens on public health in North America and *** explore the threat *** presents to the elderly,pregnant woman and immuno-compromised individuals,many studies have focused on in-host infection mechanisms and risk evaluation in terms of dose-response ***,the connection of these two foci has received little attention,leaving risk prediction with an insufficient mechanistic ***,there is a critical need to quantifiably link in-host infection pathways with the doseresponse *** better understand these relationships,we propose a new mathematical model to describe the gastro-intestinal pathway of *** within the *** model dynamics are shown to be sensitive to inoculation doses and exhibit bistability *** the model to guinea pigs,we show how it provides useful tools to identify key parameters and to inform critical values of these parameters that are pivotal in risk *** preliminary analysis shows that the effect of gastroenvironmental stress,the role of commensal microbiota and immune cells are critical for successful infection of *** and for dictating the shape of the doseresponse curves.

关键词： L.monocytogenes Dose-response mechanistic model Bi-stable Guinea pig

Highly conductive fiber with design of dual conductive Ag/CB layers for ultrasensitive and wide-range strain sensing

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Smartmat 2023年第6期4卷 98-111页

作者： ben Niu Su Yang Yiyi Yang Tao Hua School of Fashion&Textiles The Hong Kong Polytechnic UniversityHong Kong SARChina

Recently the ever-increasing demand for wearable electronics has greatly triggered the development of flexible strain ***,it is still challenging to simultaneously achieve high sensitivity,wide working range,and good ***,we developed a highly stretchable fiber strain sensor based on wet-spun porous polyurethane(PU)fiber,and especially a unique conductive network of dual silver(Ag)/carbon black(CB)layers is *** strain,the rapid crack propagation on the brittle Ag layer brings a large resistance change and thus high sensitivity,while the tunneling-effect dominated CB layer bridges the separated Ag islands to maintain the integrity of conductive pathways under large *** means of the synergistic effect of Ag/CB layers,this composite fiber of Ag/CB@PU presents not only high conductivity of 5139.9 S/m,but also ultrahigh sensitivity with a gauge factor of 2.52×10^(6) and a wide working range of up to 200%.Besides that,it is also capable of detecting very tiny strain of 0.1%and working stably for over 8000 *** mature weaving technology,this fiber strain sensor can be seamlessly integrated into the textile to conformally track different movements of the human *** with the facile all-solution-based fabrication protocol,this work proposed a new strategy to prepare high-performance fiber strain sensor,promising the textile-based wearable applications.

关键词： carbon black conductive fiber strain sensor textile