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Dependence of Deformation Twinning on Grain Orientation and Texture Evolution of High Manganese TWIP Steels at Different Deformation Temperatures

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Journal of Iron and Steel Research International 2011年第11期18卷 46-52页

作者： FANG Xiu-hui YANG Ping LU Fa-yun MENG Li School of Materials science and engineering University of Science and Technology Beijing Beijing 100083 China

Mechanical properties, microstructure and texture evolution were studied in two tensile-deformed high manganese TWIP steels at different temperatures. Special attention was paid to the effects of deformation tempera- ture and grain orientation on twinning behavior. The results showed that, at --70 ℃ and at room temperature, both twins and hexagonal martensite were found in a lower manganese steel of 26Mn. With deformation temperature ris- ing, twins became less and they disappeared at 500 ℃. Strong 〈111〉 texture appeared at 300 ℃, while it weakened at 500 ℃ due to the low strain rate and higher stacking fault energy. EBSD measurement revealed the dependence of deformation twinning on grain orientation at all test temperatures.

关键词： high manganese steel warm deformation TWIP effect texture

Influence of iron on phase and magnetic property of the LaFe_(11.6)Si_(1.4) compound

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Journal of Rare Earths 2011年第4期29卷 354-358页

作者：陈湘陈云贵唐永柏 School of Materials science and engineering Sichuan University engineering and Technology College Neijiang Normal University

The phase relation, microstructure, Curie temperatures, hysteresis, and magnetocaloric effects of LaFex＊11.6Si1.4 （x=0.96, 0.98, 1.0, and 1.02） compounds prepared by arc-melting and then annealed at 1423 K （1.5 h）＋1523 K （4.5 h） were investigated. The main phase was NaZn13-type phase, the impurity phases included a small amount of α-Fe and LaFeSi phase in four samples. The crystal cell parameters of 1：13 phase increased from 1.1433（5） to 1.1454（4） nm with x increasing from 0.96 to 1.02, respectively. All samples kept the typical first-order magnetic transition. The increase of Fe strengthened IEM behavior, and led to the remarkable enhancement of MCE effect and negative slopes in Arrott plots around TC. The maximum ΔSM （T, H） under a low magnetic field （0–2 T） was 15.3, 16.8, 17.9, and 24.7 J/kg K with increasing of Fe content from x=0.96 to 1.02, respectively.

关键词： LaFex*11.6Si1.4 compounds short-time and high-temperature annealing hysteresis magnetocaloric effect rare earths

Monolithic white LED based on Al_xGa_(1-x) N/InyGa_(1-y)N DBR resonant-cavity

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Journal of Semiconductors 2009年第1期30卷 30-33页

作者：陈宇黄黎蓉朱珊珊 College of Optoelectronics science & engineering Huazhong University of Science and Technology Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology

A monolithic white light-emitting diode （LED） with blue and yellow light active regions has been designed and studied. With the AlxGa1-xN/InyGa1-yN distributed Bragg reflector （DBR） resonant-cavity, the extraction... 详细信息

关键词： monolithic white light-emitting diode distributed Bragg reflector resonant-cavity

In situ anchor of magnetic Fe304 nanoparticles onto natural maifanite as efficient heterogeneous Fenton-like catalyst

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Frontiers of Materials science 2016年第3期10卷 300-309页

作者： Hang ZHAO Ling WENG Wei-Wei CUI Xiao-Rui ZHANG Huan-Yan XU Li-Zhu LIU School of Materials science and engineering Harbin University of Science and Technology Harbin 150040 China

In situ anchor of magnetic Fe304 nanoparticles （NPs） onto the surface of natural maifanite was realized by chemical oxidation coprecipitation in hot alkaline solution. The Fe304/maifanite composites were characterized by XRD, FTIR, SEM, and TEM. These results indicated that polycrystalline Fe304 NPs with inverse spinel structure were formed and tightly dispersed on maifanite surface. Based on the measurement of surface Zeta potential of maifanite at different medium pHs, the possible combination mechanism between natural maifanite and Fe304 NPs was proposed. Then, the as- obtained composites were developed as highly efficient heterogeneous Fenton-like catalyst for the discoloration of an azo dye, Methyl Orange （MO）. The comparative tests on MO discoloration in different systems revealed that Fe304/maifanite composite exhibited much higher Fenton-like catalytic activity than Fe304 NPs and the heterogeneous Fenton- like reaction governed the discoloration of MO. Kinetic results clearly showed that MO discoloration process followed the second-order kinetic model. Fe304/maifanite compo- sites exhibited the typical ferromagnetic property detected by VSM and could be easily separated from solution by an external magnetic field.

关键词： maifanite Fe304 NPs mechanism Fenton-like catalyst Methyl Orange (MO)

Numerical simulation of flow characteristics for a labyrinth passage in a pressure valve

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Journal of Hydrodynamics 2016年第4期28卷 629-636页

作者：王海民赵越汪建兴孔祥帅刘欢李科良王喜芳 School of Energy and Power engineering University of Shanghai for Science and Technology Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power engineering University of Shanghai for Science and Technology

A tortuous labyrinth passage consists of a series of right angle turns in a disk of high pressure control *** this paper,numerical simulations are made for the velocity and pressure distributions in this *** is shown that the “series passage” can induce a pressure dropping more *** main function of the “series passage” is to induce a pressure dropping while the “parallel passage” is mainly to regulate the *** a cross sectional area process,a series of reduction and expansion,the pressure will also see dropping and partial recovery,which is called the multistage pressure *** this way,the velocity can be controlled in a reasonable level anywhere in this tortuous labyrinth *** the fluid pressure dropping in a downwards serrated way,the pressure is higher than the local saturate vapor pressure,therefore,no cavitation is induced by the phase transition.

关键词： passage valve dropping multistage turns sectional anywhere regulate vortex inlet

Standard model of knowledge representation

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Frontiers of Mechanical engineering 2016年第3期11卷 275-288页

作者： Wensheng YIN School of Mechanical science and engineering Huazhong University of Science and Technology Wuhan 430074 China

Knowledge representation is the core of artificial intelligence research. Knowledge representation methods include predicate logic, semantic network, computer programming language, database, mathematical model, graphics language, natural language, etc. To establish the intrinsic link between various knowledge representation methods, a unified knowledge representa- tion model is necessary. According to ontology, system theory, and control theory, a standard model of knowledge representation that reflects the change of the objective world is proposed. The model is composed of input, processing, and output. This knowledge representation method is not a contradiction to the traditional knowledge representation method. It can express knowledge in terms of multivariate and multidimensional. It can also express process knowledge, and at the same time, it has a strong ability to solve problems. In addition, the standard model of knowledge representation provides a way to solve problems of non-precision and inconsistent knowledge.

关键词： knowledge representation standard model ontology system theory control theory multidimensional representation

Nonlinearity-Compensation-Free Optical Frequency Domain Reflectometry Based on Electrically-Controlled Optical Frequency Sweep

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Journal of Electronic science and Technology 2021年第1期19卷 89-96页

作者： Fan Yang Ling-Jie Zhang Zhi-Yao Zhang Xiao-Jun Zhou Yong Liu the School of Optoelectronic science and engineering University of Electronic Science and Technology of ChinaChengdu 610054

A nonlinearity-compensation-free optical frequency domain reflectometry(OFDR)scheme is proposed and experimentally demonstrated based on the electrically-controlled optical frequency *** the proposed scheme,the linear frequency sweep light is generated by propagating an ultra-narrow-linewidth continuous-wave(CW)light through an electro-optic frequency shifter which consists of a dual-parallel Mach-Zehnder modulator(DPMZM)and an electronic 90°hybrid,where the electro-optic frequency shifter is driven by a linear frequency modulated signal generated by a direct digital synthesizer(DDS).Experimental results show that the spatial resolution and signal-to-noise ratio(SNR)of the proposed OFDR scheme without the nonlinear phase compensation are comparable to those of OFDR employing a commercial tunable laser source(TLS),an auxiliary interferometer,and a software-based nonlinear phase compensation *** proposed OFDR scheme is helpful to reduce the complexity of the optical structure and eliminate the difficulty of developing the nonlinear phase compensation algorithm.

关键词： Dual-parallel Mach-Zehnder modulator(DPMZM) electro-optic frequency shifter optical fiber sensor optical frequency domain reflectometry(OFDR)

OXIDATION BEHAVIOR OF KOVAR ALLOY IN CONTROLLED ATMOSPHERE

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Acta Metallurgica Sinica(English Letters) 2008年第6期21卷 409-418页

作者： D. W. Luo Z.S. Shen School of Materials science and engineering University of Science and Technology Beijing Beijing 100083 China

Controlled oxidation experiments were performed on Kovar alloy by changing oxidation atmosphere, temperature, and exposure time to produce films with different oxide type and thickness. The results indicated that single Fe3O4 and single FeO were respectively obtained when Kovar alloy was oxidized in N2-2.31%H2O-0.95%H2 at 500℃ and in N2-2.31%H2O-0.5%H2 at 1000℃, and all kinetic curves followed linear relation; mixed oxides of FeO and Fe3O4 formed when Kovar was oxidized in N2-2.31%H2O at 1000℃and parabolic kinetics were obeyed. Analysis of metallographic cross section of oxides indicated that oxygen diffusion inward through the oxide scale is responsible for intergranular oxide, which had formed beneath the oxide scales when the oxide products were mixed oxides of FeO and Fe3O4, and which did not occur when the oxide was single FeO or Fe3O4. The oxidation model was also established.

关键词： Kovar alloy, Oxidation Controlled atmosphere H2-H2O-N2

Effect of Environmental Factors on Electrochemical Behavior of X70 Pipeline Steel in Simulated Soil Solution

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Journal of Iron and Steel Research International 2009年第6期16卷 52-57页

作者： ZHANG Liang LI Xiao-gang DU Cui-wei School of Materials science and engineering University of Science and Technology Beijing Beijing 100083 China

Potentiodynamic polarization measurement was used to investigate the effects of temperature, dissolved ox- ygen concentration and pH on the electrochemical behavior of X70 pipeline steel in simulated solution according to the orthogonal testing method. The results showed that temperature, dissolved oxygen concentration and pH had great influence on corrosion current density （icorr） of X70 steel. Corrosion current density of X70 steel was most influenced by dissolved oxygen concentration in simulated solution. The corrosion degree of X70 steel was the least under the environment of low temperature, deficient oxygen and weak acid.

关键词： X70 pipeline steel potentiodynamic polarization measurement orthogonal testing corrosion current density