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In-vivo retinal imaging by optical coherence tomography using an RSOD-based phase modulator

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 607-612页

作者： Ling WANG Zhi-hua ding Guo-hua SHI Yu-dong ZHANG State Key Laboratory of Modern Optical Instrumentation Zhejiang University Hangzhou 310027 China Institute of Optics and Electronies Chinese Academy of Sciences Chengdu 610209 China

Fourier-domain rapid scanning optical delay line (RSOD) was introduced for phase modulation and depth scanning in a time-domain optical coherence tomography (TD-OCT) system. Investigation of parameter optimization of RSOD was conducted. Experiments for RSOD characterization at different parameters of the groove pitch, focal length, galvomirror size, etc. were performed. By implementing the optimized RSOD in our established TD-OCT system with a broadband light source centered at 840 nm with 50 nm bandwidth, in vivo retina imaging of a rabbit was presented, demonstrating the feasibility of high-quality TD-OCT imaging using an RSOD-based phase modulator.

关键词： Optical coherence tomography (OCT) Phase modulation Retina imaging

AFFINE TRANSFORMATION IN RANDOM ITERATED FUNCTION SYSTEMS

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Applied Mathematics and Mechanics(English Edition) 2001年第7期22卷 820-826页

作者： XIONG Yong(熊勇) SHI ding-hua(史定华) Department of Mathematics Shanghai University Shanghai 200436 P R China Department of Mathematics Shanghai University Shanghai 200436 P R China

Random iterated function systems (IFSs) is discussed, which is one of the methods for fractal drawing. A certain figure can be reconstructed by a random IFS. One approach is presented to determine a new random IFS, that the figure reconstructed by the new random IFS is the image of the origin figure reconstructed by old IFS under a given affine transformation. Two particular examples are used to show this approach.

关键词： fractal random iterated function system affine transformation

Effect of silicon and prior deformation of austenite on isothermal transformation in low carbon steels

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Acta Metallurgica Sinica(English Letters) 2009年第2期22卷 100-109页

作者： Minghui CAI hua ding Jiansu ZHANG Long LI School of Materials and Metallurgy Northeastern University Shenyang 110004 China Technology Center Baoshan Iron and Steel Co. Ltd. Shanghai 201900 China National Institute for Materials Science Tsukuba 305-0047 Japan

Isothermal transformation （TTT） behavior of the low carbon steels with two Si contents （0.50 wt pct and 1.35 wt pct） was investigated with and without the prior deformation. The results show that Si and the prior deformation of the austenite have significant effects on the transformation of the ferrite and bainite. The addition of Si refines the ferrite grains, accelerates the polygonal ferrite transformation and the formation of M/A constituents, leading to the improvement of the strength. The ferrite grains formed under the prior deformation of the austenite become more homogeneous and refined. However, the influence of deformation on the tensile strength of both steels is dependent on the isothermal temperatures. Thermodynamic calculation indicates that Si and prior deformation reduce the incubation time of both ferrite and bainite transformation, but the effect is weakened by the decrease of the isothermal temperatures.

关键词： Low carbon steel Si content Prior deformation of austenite Ferrite transformation Bainite transformation

Effect of Intercritical Annealing Time on the Microstructures and Tensile Properties of a High Strength TRIP Steel

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Acta Metallurgica Sinica(English Letters) 2014年第3期27卷 457-463页

作者： Chao Wang hua ding Jun Zhang Hongyan Wu School of Materials and Metallurgy Northeastern University State Key Laboratory of Rolling and Automation Northeastern University

A new Mn-Si-Al-Mo-Nb transformation-induced plasticity steel was annealed by intercritical annealing for different durations to investigate the partitioning of C element and the volume fraction change of the microstructural constituents. Direct experimental evidence confirms the partitioning of C elements in different phases during heat treatment by Electron probe microanalysis and X ray diffraction. The distribution of the precipitates was investigated as well. It was revealed that the microstructures and mechanical properties of the investigated steels were affected by the intercritical annealing time. According to the present experiment, the volume fraction of retained austenite and the product of tensile strength and total elongation of investigated steel decrease with increasing intercritical annealing time. It was observed that high tensile strength of 1,103 MPa, total elongation of 21.3%, and strength-ductility product of 23,493.9 MPa % could be successfully produced in this experimental steel at intercritical annealing temperature of 830 ℃, holding for 1 min, and isothermal bainite treatment of 440 ℃ for 5 min holding time.

关键词： TRIP steel Intercritical annealing Carbon partitioning Retained austenite Stability

A Comparative Study of Various Flow Instability Criteria in Processing Map of Superalloy GH4742

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Journal of Materials Science & Technology 2014年第3期30卷 217-222页

作者： Ge Zhou hua ding Furong Cao Beijiang Zhang College of Materials and Metallurgy Northeastern University High Temperature Materials Division Central Iron and Steel Research Institute

Hot compression tests were conducted on a Gleeble-1500D thermal simulating tester. Based on the deformation behavior and microstructural evolution of superalloy GH4742, different types of instability criteria of Prasad, Gegel, Malas, Murty and Semiatin were compared, and the physical significance of parameters was analyzed. Meanwhile, the processing maps with different instability criteria were obtained. It was shown that instability did not occur when average power dissipation rate was larger than 50% in the temperature range of 1020- 1130℃, corresponding to the strain rate range of 5 × 10-4-3.2 × 10-3 s-1. The domain is appropriate for the processing deformation of superalloy GH4742.

关键词： GH4742 superalloy Hot compression tests Flow instability criterion Processing map

Microstructures and Mechanical Properties of Si-AI-Mn TRIP Steel with Niobium

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Journal of Materials Science & Technology 2007年第6期23卷 790-794页

作者： Zhengyou TANG hua ding Linxiu DU Long LI College of Materials and Metallurgy State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 China State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 China.

Microstructure consisting of ferrite, bainite and retained austenite can be obtained through intercritical annealing and isothermal treatment in bainite transformation region for low silicon TRIP （transformation induced plasticity） steel containing niobium. Effects of strain rate, Nb content and soaking temperature in bainite region on microstructure and mechanical properties of test steels were investigated. It is shown that as strain rate ranges from 10^-2 to 10^-4 s^-1, the volume fraction of transformed martensite from retained austenite, as well as tensile strength, elongation rate and strength-ductility product, increases. When Nb is added, the volume fraction of retained austenite decreases, but tensile strength and yield strength increase. While Nb content reaches 0.014%, the steel exhibits high elongation and combination of strength and ductility. Higher retained austenite volume fraction and good mechanical properties are obtained in the test steels when the soaking temperature in bainite region is 400℃. The maximum values of tensile strength, total elongation rate and strength-ductility product can reach 739 MPa, 38% and 28082 MPa%, respectively.

关键词： TRIP Strain rate Niobium content Retained austenite Mechanical properties

Recent advances of Pd-π-allyl zwitterions in cycloaddition reactions

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Chinese Chemical Letters 2023年第11期34卷 3-19页

作者： Juan Du Yun-Fan Li Chang-hua ding Guangxi Key Laboratory of Natural Polymer Chemistry and Physics College of Chemistry and MaterialsNanning Normal UniversityNanning 530001China Department of Chemistry Shanghai Engineering Research Center of Organ RepairInnovative Drug Research CenterShanghai UniversityShanghai 200444China

Palladium-catalyzed cycloaddition reactions via Pd-π-allyl zwitterions have been established as significant synthetic transformations to enable numerous carbon-or heterocycles compounds that are key constituents of various biologically active natural products and *** addition to the well-known Pd-π-allyl zwitterions,including palladium-trimethylenemethane and Pd-1,3/1,4-zwitterions,chemists have recently discovered new applications of several long ago reported but less-studied Pd-π-allyl zwitterions,which can straightforwardly and efficiently construct novel cyclic ***,some impressive newly designed zwitterions have been also *** zwitterions are diverse and can serve as transient and highly reactive intermediates for the subsequent cyclization with various *** this review,we highlight recent advances in applications of these two types of zwitterions in the synthesis of complex polycyclics and medium-sized cyclic compounds.

关键词： Palladium Cycloaddition Pd-π-allyl zwitterions Asymmetric catalysis Heterocycles

Interfacial microstructure and mechanical properties of stainless steel clad plate prepared by vacuum hot rolling

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Journal of Iron and Steel Research International 2018年第7期25卷 732-738页

作者： Jun Jiang hua ding Zong-an Luo Guang-ming Xie School of Materials and Metallurgy Northeastern University Shenyang 110819 Liaoning China Shenyang Aircraft Corporation Shenyang 110034 Liaoning China State Key Laboratory of Roiling and Automation Northeastern University Shenyang 110819 Liaoning China

A stainless steel clad plate composed of stainless steel and carbon steel was prepared by vacuum hot rolling process, and its microstructure, especially the bonding interface, was evaluated using an optical microscope, a scanning electron micro- scope and a transmission electron microscope （TEM）. The corresponding mechanical properties were also assessed by means of hardness and shear tests. The results showed a bonding interface formed between stainless steel and carbon steel, which was relatively straight in macroscope but serrated in microscope. Decarburization layer and carbon-enriched layer were distinguished at the side of carbon steel and stainless steel near the interface, respectively, which should be related to diffusion of carbon and alloying elements. The carbon-enriched layer could also be identified as a recombination region, whose microstructure was mainly recognized as martensite by TEM. Consequently, the hardness was the highest at this region. Furthermore, the result of shear test at the bonding interface showed that the shear strength was 395 MPa and the fracture mode was dominated as ductile fracture, indicating the bonding interface with good quality.

关键词： Stainless steel clad plate Vacuum hot rolling Interface microstructure Mechanical property

Research on the intelligent design system for investment casting die of aero-engine turbine blade based on knowledge

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航空动力学报 2010年第5期25卷 1061-1067页

作者： JIANG Rui-song ZHANG ding-hua WANG Wen-hu The Key Laboratory of Contemporary Design and Integrated Manufacturing Ministry of EducationSchool of Mechanical EngineeringNorthwestern Polytechnical UniversityXi'an 710072China

To solve the problems in turbine blade investment casting die design process such as long design time,lacking of expert experience and low level of intelligence,knowledge-based engineering (KBE) was introduced in the turbine blade investment casting die design field. The key technologies of the intelligent design method were researched and a prototype system was developed. A hybrid reasoning model was prompted in which case-based reasoning (CBR) was applied to conceptual design and rule-based reasoning (RBR) was applied to parts design after research the design process and domain knowledge of casting die. In the conceptual design stage,a retrieval model which integrated nearest neighbor approach and knowledge-based retrieval approach was prompted to improve the retrieval efficiency. Meanwhile,RBR was used to modify the retrieval result. The practical application results indicate that this system can reuse the expert experience efficiently and heighten the die design efficiency and quality.

关键词： turbine blade investment casting die intelligent design knowledge-based engineering (KBE)