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Researches on the Structure and Properties of Mullite Solid Solution Made from Industrial Waste

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Chinese Journal of Structural Chemistry 2006年第8期25卷 965-970页

作者： RUAN yu-Zhong yu Yan WU ren-Ping College of Materials Science and Engineering Fuzhou University Fuzhou 350002 China

The waste slag from aluminum profile factory and silicon fine powder from ferroalloy factory were utilized as the main raw materials to synthesize mullite solid solution Al4＋2xSi2-xO10-x/2, whose defect formation mechanism, crystalline phase composition, crystal cell parameters, microstructures and morphologies were characterized in detail by XRD and SEM. The results show that because of the ultrafine particle size of the materials, the content of mullite solid solution synthesized by this method is higher than that by regular method. Keywords： waste slag from aluminum factory, silicon fine powder, mullite, solid solution

关键词： waste slag from aluminum factory silicon fine powder mullite solid solution

Studies on the Structure and Properties of Multiphase Al_2O_3 Abrasion-resistant Ceramics

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Chinese Journal of Structural Chemistry 2006年第7期25卷 805-810页

作者： WU ren-Ping yu Yan RUAN yu-Zhong College of Materials Science and Engineering Fuzhou University Fuzhou 350002 China

The Al2O3 abrasion-resistant ceramics is successfully prepared by using waste aluminum sludge as the main raw material with the addition of a little clay, talc and barium carbonate. The crystal structure and microstructure of ceramic are characterized by means of XRD, SEM, etc., and the physical and mechanical properties are also tested. The results show that besides the phase of corundum, a little mullite, Mg-Al spinel and hyalophane phases also exist in the product. These phases are produced via reaction in-situ, which can inhibit the overgrowth of Al2O3 grain in grain boundary, and improve the integral property of the material.

关键词： Al2O3 ceramic crystal structure property in-situ synthesis

Influence of pre-synthesized Al_(2)O_(3)-SiC composite powder from clay on properties of low-carbon MgO-C refractories

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Journal of Iron and Steel Research International 2022年第7期29卷 1080-1088页

作者： Bei-yue Ma Xin-ming ren Zhi Gao Fan Qian Zhao-yang Liu Guo-qi Liu Jing-kun yu Gao-feng Fu Key Laboratory for Ecological Metallurgy of Multimetallic Mineral(Ministry of Education) Shenyang 110819LiaoningChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina State Key Laboratory of Advance Refractories Sinosteel Luoyang Institute of Refractories Research Co.Ltd.Luoyang 471039HenanChina

To improve the properties of low-carbonization of MgO–C refractories,the introduction of composite additives is an effective ***_(2)O_(3)–SiC composite powder was prepared from clay using electromagnetic induction heating and carbon embedded ***,the Al_(2)O_(3)–SiC composite powder synthesized by electromagnetic induction heating at 600 A was added into low-carbon MgO–C refractories(4 wt.%)to improve their *** results showed that when the addition amount of Al_(2)O_(3)–SiC composite powder is within the range of 2.5–5.0 wt.%,the properties of low-carbon MgO–C samples were significantly improved,e.g.,the apparent porosity of 7.58%–8.04%,the bulk density of 2.98–2.99 g cm-3,the cold compressive strength of 55.72–57.93 MPa,the residual strength after three air quenching at 1100°C of 74.86%–78.04%,and the decarburized layer depth after oxidized at 1400°C for 2 h of 14.03–14.87 ***,the idea for the rapid synthesis of Al_(2)O_(3)–SiC composite powder provides an alternative low-carbon MgO–C refractories performance optimization strategy.

关键词： MgO–C refractory Electromagnetic induction heating Al_(2)O_(3)–SiC composite powder Oxidation

Development of Kabila rocket: A radioisotope heated thermionic plasma rocket engine

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Chinese Journal of Aeronautics 2015年第2期28卷 427-433页

作者： Kalomba Mboyi ren Junxue Liu yu School of Astronautics Beihang University

A new type of plasma rocket engine, the Kabila rocket, using a radioisotope heated thermionic heating chamber instead of a conventional combustion chamber or catalyst bed is intro- duced and it achieves specific impulses similar to the ones of conventional solid and bipropellant rockets. Curium-244 is chosen as a radioisotope heat source and a thermal reductive layer is also used to obtain precise thermionic emissions. The self-sufficiency principle is applied by simultane- ously heating up the emitting material with the radioisotope decay heat and by powering the differ- ent valves of the plasma rocket engine with the same radioisotope decay heat using a radioisotope thermoelectric generator. This rocket engine is then benchmarked against a 1 N hydrazine thruster configuration operated on one of the Pleiades-HR-1 constellation spacecraft. A maximal specific impulse and power saving of respectively 529 s and 32% are achieved with helium as propellant. Its advantages are its power saving capability, high specific impulses and simultaneous ease of storage and restart. It can however be extremely voluminous and potentially hazardous. The Kabila rocket is found to bring great benefits to the existing spacecraft and further research should optimize its geometric characteristics and investigate the physical principals of its operation.

关键词： Plasma Radioisotopes Rocket Self-sufficiency principleThermionic Thermoelectric power

Hybrid quantum key distribution network

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Science China(Information Sciences) 2022年第10期65卷 24-30页

作者： Siyu ren yu WANG Xiaolong SU State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-Electronics Collaborative Innovation Center of Extreme Optics Shanxi University State Key Laboratory of Cryptology

Quantum key distribution(QKD) is now moving toward a scalable and secure QKD network,which establishes secret keys among network users. The continuous-variable(CV) and discrete-variable(DV)QKD systems are currently being developed in parallel and are all used in QKD networks. We propose here a hybrid QKD network, in which the CV QKD system is used to build metropolitan QKD networks, and the DV QKD system is used to connect metropolitan QKD networks. The hybrid QKD network takes advantage of high secret key rates for CV QKD systems and long distance for DV QKD systems. We also present a feasible hybrid measurement-device-independent(MDI) QKD network, which combines both CV and DV MDI QKD systems. The presented hybrid QKD networks meet the low cost and compact requirement of a realistic QKD network and provide a feasible solution for future real QKD networks by combining the advantages of both CV and DV QKD systems.

关键词： quantum network quantum key distribution hybrid quantum information continuous variable discrete variable

Flow and transport simulation of Madeira River using three depth-averaged two-equation turbulence closure models

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Water Science and Engineering 2012年第1期5卷 11-25页

作者： Li-ren yu Environmental Software and Digital Visualization(ESDV) Sao Carlos 13561-120Brazil Association of United Schools-Higher Education Center of Sao Carlos(ASSER-CESUSC) Sao Carlos 13574-380Brazil

This paper describes a numerical simulation in the Amazon water system, aiming to develop a quasi-three-dimensional numerical tool for refined modeling of turbulent flow and passive transport of mass in natural waters. Three depth-averaged two-equation turbulence closure models, k-ε,k-w, and k-w, were used to close the non-simplified quasi-three-dimensional hydrodynamic fundamental governing equations. The discretized equations were solved with the advanced multi-grid iterative method using non-orthogonal body-fitted coarse and fine grids with collocated variable arrangement. Except for steady flow computation, the processes of contaminant inpouring and plume development at the beginning of discharge, caused by a side-discharge of a tributary, have also been numerically investigated. The three depth-averaged two-equation closure models are all suitable for modeling strong mixing turbulence. The newly established turbulence models such as the k-w model, with a higher order of magnitude of the turbulence parameter, provide a possibility for improving computational precision.

关键词： river modeling," numerical modeling contaminant transport," depth-averaged turbulence models multi-grid iterative method

Computation of the stability derivatives via CFD and the sensitivity equations

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Acta Mechanica Sinica 2011年第2期27卷 179-188页

作者： Guo-Dong Lei yu-Xin ren Department of Engineering Mechanics Tsinghua University 100084 Beijing China

The method to calculate the aerodynamic stability derivates of aircrafts by using the sensitivity equations is ex- tended to flows with shock waves in this paper. Using the newly developed second-order cell-centered finite volume scheme on the unstructured-grid, the unsteady Euler equations and sensitivity equations are solved simultaneously in a non-inertial frame of reference, so that the aerodynamic stability derivatives can be calculated for aircrafts with complex geometries. Based on the numerical results, behavior of the aerodynamic sensitivity parameters near the shock wave is discussed. Furthermore, the stability derivatives are analyzed for supersonic and hypersonic flows. The numerical results of the stability derivatives are found in good agree- ment with theoretical results for supersonic flows, and variations of the aerodynamic force and moment predicted by the stability derivatives are very close to those obtained by CFD simulation for both supersonic and hypersonic flows.

关键词： Aerodynamic stability derivatives Non-inertial frame of reference unstructured-grid Finite volume scheme Sensitivity equations

A survey on fabrication,control,and hydrodynamic function of biomimetic robotic fish

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Science China(Technological Sciences) 2017年第9期60卷 1365-1380页

作者： yu JunZhi WEN Li ren Ziyu State Key Laboratory of Management and Control for Complex Systems Institute of AutomationChinese Academy of Sciences School of Mechanical Engineering and Automation Beihang University

Understanding and replicating the locomotion principles offish are fundamental in the development of artificial fishlike robotic systems,termed robotic *** paper has two objectives:(1) to review biological clues on biomechanics and hydrodynamic flow control offish swimming and(2) to summarize design and control methods for efficient and stable swimming in robotic *** review of state-of-the-art research and future-oriented new directions indicates that fish-inspired biology and engineering interact in mutually beneficial *** strong interaction offers an important insight into the design and control of novel fish-inspired robots that addresses the challenge of environmental uncertainty and competing objectives;in addition,it also facilitates refinement of biological knowledge and robotic strategies for effective and efficient swimming.

关键词： fish swimming robots robotic fish hydrodynamics motion control

Solidification structure of eutectic Al-Si alloy under a high magnetic field-aid-electromagnetic vibration

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Acta Metallurgica Sinica(English Letters) 2009年第3期22卷 191-196页

作者： Jianbo yu Zhongming ren Weili ren Kang DENG yunbo ZHONG Department of Materials Science and Engineering Shanghai University Shanghai 200072 China

An electromagnetic vibration was generated by simultaneously imposing a strong static magnetic field （up to 10 T） and an alternative electricity current to the metal. Its effects on the solidification structure of eutectic Al-Si alloy have been investigated experimentally. It is found that the eutectic structure has been refined by solely imposing high magnetic field while it is coarsened under the electromagnetic vibration. Furthermore, polyhedral Si grains and non-dendritic α-Al appeared when the electromagnetic vibration strength was strong enough. The refining of eutectic structure is attributed to the decrease of diffusion coefficient caused by the strong magnetic field. The coarseness of eutectic structure may be attributed to the convection caused by electromagnetic vibration. Strong convection may break co-operative growth of eutectic phases to form polyhedral Si grains and non-dendritic α-Al.

关键词： Strong magnetic field Electromagnetic vibration Eutectic solidification Polyhedral Si Al-Si alloy