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Pattern scaling effect on the radiative properties of wafer's surface

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Science china(Technological Sciences) 2010年第7期53卷 1886-1892页

作者： WANG AiHua & CAI JiuJu School of Materials and Metallurgy, northeastern university, shenyang 110819, china 1. School of Materials and Metallurgy Northeastern University Shenyang 110819 China

This paper presents a parametric study of the radiative properties of patterned wafers with a polysilicon gate array on the Si substrate, considering the effect of wavelength and polarization. The finite-difference time-domain (FDTD) method was employed to examine the pattern scaling effect on the spectral absorptance via numerical solutions of the Maxwell's equations. The effective medium theory (EMT) was also used to help explain the absorptance predictions. While the gate sizes are very small compared to wavelength, the results show rather unusual phenomena. The absorptance calculated by EMT is in agreement with FDTD in the cases with small gate and period sizes. With the increase of period and decrease of the ratio of the gate width to the grating period, both EMT and FDTD results for the TM (transverse magnetic) mode approach to pure silicon since the grating effect diminishes. However, the error of EMT results for the TE mode in some cases becomes considerable due to the limitation of EMT, which requires the period to be significantly smaller than the wavelength. Besides, the TE (transverse electric) absorptance curve separates from that of plain Si when the wavelength equals the grating period, this is because the gate can interact with its neighbering region by diffraction and the diffraction effects are weak, when the wavelength is small. The peak absorptance can be attributed to the thin film effect. It shows that a slight increase in the gate height can drastically increase the absorptance and the increased gate height shifts the peak absorptance to longer wavelength due to the increase of optical path length in the effective thin film. This work is of great importance for optimization of advanced annealing techniques in semiconductor manufacturing.

关键词： finite-difference time-domain method effective medium theory radiative property resonance cavity effect patterned wafer

Micro-alloying of Rare Earths in Heavy Rail Steel

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稀有金属材料与工程 2011年第S3期40卷 245-249页

作者： Huang Yahe, Liu Chengjun, Jiang Maofa northeastern university, shenyang 110819, china northeastern Univ Sch Met & Mat Shenyang 110819 Peoples R China

In the present study, heavy rail steel was prepared by the process of vacuum induction furnace smelting, forge work and rolling. Effects of Rare earths (RE) on microstructure and mechanical properties of heavy rail steel were systematically investigated by metallographic microscope, SEM, integrated mechanical testing machine, impact tester and so on. Metallographic analysis shows that, a few of RE can evidently delay the growth of austenite grain and fine pearlite. When the RE content is 0.016%, both annealing and normalizing pearlite laminae distances reach the minimum which is 115 nm (annealing) and 104nm (normalizing), respectively. But when the RE content reaches 0.13.%, the annealing and normalizing pearlite laminae distance is respectively increased by 40% and 13.. Mechanical properties tests show that, a few of RE has not notable effect on the strength, but both plasticity and ductility can be improved obviously. When the RE content is 0.016%, both plasticity and ductility reach maximum. The maximum of elongation and reduction of area is 13.3. and 29.0%, respectively. However, when the RE content reaches 0.13.%, the strength, plasticity and ductility are decreased. Especially, the low temperature (-40 ℃) and room temperature (20 ℃) ballistic work is respectively decreased by 9% and 24.8%.

关键词： rare earths heavy rail steel austenite pearlite mechanical properties

Study on Microstructure and Mechanical Properties of Hot Rolled Low Silicon Containing Phosphorus TRIP Steel

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稀有金属材料与工程 2011年第S3期40卷 228-233页

作者： Hou Xiaoying, Xu Yunbo, Wu Di State Key Laboratory of Rolling and Automation, northeastern university, shenyang 110819, china northeastern Univ State Key Lab Rolling & Automat Shenyang 10819 Peoples R China

The effects of final air cooling temperature on the microstructure and mechanical properties of hot rolled 0.2C-1.9Mn-0.5Si-0.08P TRIP steel were studied by utilizing OM, SEM, TEM and tensile tests. Experimental results showed that in the multiphase microstructure of the investigated steel when the finish rolling temperature was about 820 ℃ and the final air cooling temperature was in the range of 63.-700 ℃, the grain size of most of ferrite was finer (about 4 μm) and which had higher dislocation density, the bainite packets had chaotic orientations and lath boundaries of bainite were not quite straight, the retained austenite distributed in the ferrite grain boundaries or triradius was fine and dispersive, and their grain size was about 0.4-1.9 μm. With increasing the amount of ferrite, the volume fraction of retained austenite had a slight decrease. When the final air cooling temperature was 63. ℃, the steel had excellent mechanical properties, which was characterized by combination of continuous yielding, high strength (about 796 MPa) and high elongation (22.7%) as well as low yield/strength ratio (0.58); when the final air cooling temperature increased to 700 ℃, the matrix structure was bainite packets and the comprehensive properties were deteriorated.

关键词： hot rolled TRIP steel low silicon containing phosphorus microstructure and mechanical properties final air cooling temperature

Level Set Based on Signed Pressure Force Function and Its Application in Liver Image Segmentation

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Wuhan university Journal of Natural Sciences 2011年第3期16卷 265-270页

作者： JIANG Huiyan1,2,FENG Ruijie2,3.GAO Xihe1,2 1.Software College,northeastern university,{3. {3.,Liaoning,china 2.Key Laboratory of Medical Image Computing of Ministry of Education northeastern university,{3. {3.,Liaoning,china 3.Sino-Dutch Biomedical and Information Engineering School,northeastern university,{3. {3.,Liaoning,china Software College Northeastern University Shenyang Liaoning China Key Laboratory of Medical Image Computing of Ministry of Education northeastern university Shenyang Liaoning China Sino-Dutch Biomedical and Information Engineering School Northeastern University Shenyang Liaoning China

The edge-based level set model gives no satisfactory results for images with weak edge, and the region-based model performs poorly for intensity inhomogeneity images. In this paper, we propose an improved region-based level set model that integrates both the gradient information and the region information. The proposed model defines a novel external energy term, which consists of gradient information and signed pressure forces function. In order to eliminate the re-initialization procedure of traditional level set model, an internal energy term is also introduced for the level set function to maintain signed distance function. Compared with traditional models, our model is more robust against images with weak edge and intensity inhomogeneity. Experiments on liver segmentation from abdominal CT images demonstrate the effectiveness and accuracy of the proposed method.

关键词： segmentation level set signed pressure force liver

EFFECT　OF　HOMOGENIZATION　TREATMENT　UNDER　AN　ELECTRIC　FIELD　ON　T_1　DISTRIBUTION　AND　MECHANICAL　PROPERTIES　OF　2091　Al－Li　ALLOY

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Acta Metallurgica Sinica(English Letters) 1995年第2期8卷 126-129页

作者： LIU Wei CUI Jianzhong(northeastern university,shenyang,{{3.) northeastern Univ Shenyang China

Homogenization treatment under an electric field increases the distributive homogeneity of the T1 precipitation and improves the yield strength of 2091 Al-Li alloy.

关键词： homogenization treatment 2091 Al-Li alloy electric field T_1 precipitation

Effect of Ti-enriched Carbonitride on Microstructure and Mechanical Properties of X80 Pipeline Steel

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Journal of Materials Science & Technology 2010年第9期26卷 803-809页

作者： Wei Deng,Xiuhua Gao,Dewen Zhao,Linxiu Du,Di Wu and Guodong Wang State key laboratory of rolling and automation,northeastern university,shenyang {{3.,china [a]State key laboratory of rolling and automation Northeastern University Shenyang 110819 China

In this study,two API X80 pipeline steels were fabricated by varying Ti additions,and their microstructures and fracture characteristics were analyzed to investigate the effects of Ti-enriched carbonitride on the tensile properties and Charpy impact *** bainite,a mass of matensite/austenite（M/A）,coarse cubic Ti-enriched inclusions,chain-typed Ti-enriched precipitations,weak toughness and high tensile strength were found as consequences of higher amount of Ti *** large scale and chain-typed Ti-enriched carbonitrides are one kind of crack sources during *** negative effect of higher amount of Ti on the impact properties is increased with decreased temperature.

关键词： X80 pipeline steel Ti-enriched carbonitride Matensite/austenite(M/A) constitute Impact toughness

MAfHEMAfICAL MODEL FOR MELTING PROCESSES OF SOLID ARTICLES IMMERSED IN METAL BATHS

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Acta Metallurgica Sinica(English Letters) 1999年第3期12卷 259-266页

作者： B.K. Li X.F. Ma X.R. Zhang and J.C. He (northeastern university, shenyang 110006,{{3.)(northeastern university, shenyang 110006,{{3.)(northeastern university, shenyang 110006,{{3.)(northeastern university, shenyang 110006,{{3.) northeastern university Shengyang China

A mathematical model for melting processes of solid particles immersed in metal baths has been develOPed, which includes the cases with the melting point of solid particles greater than, equal to, and lower than freezing point of the bath. Experiments are performed on the melting of ice spheres in water at different temperature. The model is validated by experimental data for melting of ice spheres submerged in water and aluminum spheres immersed in aluminum melt. Finally, the parometers affecting particles melting time such as particle size, bath temperature, and slip velocity are analyzed.

关键词： mathematical model phase change solid particle

Nonisothermal Behavior of Oxidation of Natural Ilmenite Pellet

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Rare Metals 2000年第3期19卷 222-226页

作者： Sun Kang (孙康) School of Materials and Metallurgy,northeastern university,shenyang 110006,{{3. northeastern Univ Sch Met & Mat Shenyang 110006 Peoples R China

The nonisothermal behavior of the oxidation of natural ilmenite pellets was interpreted in the light of a nonisothermal kinetic model which fits the experimental results very *** rate of the overall oxidation was predominantly controlled by the intrapellet diffusion of oxygen and the rate of heat transfer was mainly limited by the heat conduction through the product *** oxidation of natural ilmenite pellet can not be treated as an isothermal reaction system within the temperature range of 1073. 1173. unless the concentration of oxygen in the gaseous reactants is less than 10 mol%.

关键词： Nonisothermal behavior Oxidation Ilmenite Kinetic model Rate controlling step

Electronic Structures and Alloying Behaviors of Ferrite Phases in High Co-Ni Secondary Hardened Martensitic Steels

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Journal of Materials Science & Technology 2000年第5期16卷 495-498页

作者： Guoying ZHANG+ and Meiguang ZENG (northeastern university, shenyang 110006,{{3.) Guili LIU (shenyang Polytechnic universityt shenyang 11002{3.{{3.) northeastern university Shenyang 110006 China shenyang Polytechnic university Shenyang 110023 China

The electronic structure of ferrite (tempered martensite phase) in high Co-Ni secondary hardened martensitic steel has been investigated. The local density of states (LOOS) of alloying elements in the steel displays the relationship between solid solubility and the shape of the LDOS. The bond order integral (BOI) between atoms in the steel shows that the directional bonding of the p orbital of Si or C leads to the brittleness of the steel. At last, ΣBOI between atoms demonstrate that C, Co, Mn, Cr, Mo, Si strengthen the alloyed steel through solid-solution effects.

关键词： Electronic Structures and Alloying Behaviors of Ferrite Phases in High Co-Ni Secondary Hardened Martensitic Steels Ni