Al2O3—Si3N4—ZrO2多相复合材料在燃煤MHD发电中的应用

采用Ａｌ２Ｏ３基料，添加第二相（ＺｒＯ２，Ｓｉ３Ｎ４）和纤维相（ＺｒＯ２，（ｆ），以热压法制成Ａｌ２Ｏ３－Ｓｉ３Ｎ４－ＺｒＯ２多相复合材料。研究表明，新材料在青静态和动态试验中表现出良好的综合性能：１０７３Ｋ时的高温电阴率ｐ＝１．２４×１７＾７Ω．ｃｍ；静态熔渣最大腐蚀速率Ｖｓ＝０．１６μｍ／ｈ；动态最大腐蚀速率Ｖｄ＝０．４４９μｍ／ｈ。与Ａｌ２Ｏ３陶瓷相比，室温抗弯强度提高９３％，抗热震临界...     

Modulation of iron–nickel layers composition by an external magnetic field

In this article, characterization of FeNi layers deposited on a Cu plate for variable magnetic field arrangement is shown. Layers were prepared using a simple electrodeposition process, from an aqueous solution of Fe²⁺ and Ni²⁺ sulfate salts containing boric acid, an iron activator. By application of variation of current values, times, and external magnetic field orientations, the resultant film quality was examined and the efficiency of the embedded elements was investigated. The studies show differences in the coating morphology and relative composition of ferromagnetic metals (Ni, Fe) electrodeposited on a not ferromagnetic (paramagnetic) metal (Cu). The obtained layers were investigated by Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy.     

火炸药在MHD中的应用及发展

本文论述了正在研究发展中以火药燃烧或炸药驱动产生高温等离子体为工质的大功率磁流体(MHD)技术,阐述了火炸药转化为大功率电磁波的原理,简单介绍了等离子体及其用于此方面特殊的电磁性质。概述了国内外火炸药用于产生大功率电磁波的发展状况,并探讨了其优点及应用,最后指出了目前所面临的问题。     

Soft x-ray tomographic reconstruction of Heliotron J plasma for the study of magnetohydrodynamic equilibrium and stability

The preparation for an experimental soft x-ray tomography study on the Heliotron J (H-J) machine is carried out, with the objectives of evaluating the capability of the current soft x-ray tomographic system in terms of the identification of different mode structures and their poloidal rotation, and the axis shift with different plasma and machine parameters, and fixing the physics goals for the experimental study. These preparations were carried out via a simulated soft x-ray data set arising from different plasma conditions, such as magnetic islands, low beta and high beta. Soft x-ray tomography (SXT) is performed by the discrete pixel method including singular value decomposition and Phillips–Tikhonov regularization, to obtain clear and smooth images. The H-J soft x-ray tomography results from simulated soft x-rays for the equilibrium H-J plasma sensed the magnetic axis shift clearly and an estimate was also achieved. Successful reconstruction for mode structure m=1/n=1 was obtained along with the realization of the poloidal rotation of the structure. The reconstruction for the m=2/n=1 mode was not very clear for the current soft x-ray diagnostic design. Effective mode identification was not possible due to the lack of measurements. The SXT from the current soft x-ray diagnostic on H-J, the magnetic axis shift can be estimated and the m=1/n=1 mode can be studied. Study of higher poloidal modes is difficult with the current design.     

Summary of US–Japan Exchange 2004: New Directions and Physics for Compact Toroids

Scientists from research institutions in the United States of America and Japan attended a USA Department of Energy sponsored joint international workshop on the subject of Compact Toroids (CT) in Santa Fe, NM, USA in September 2004. We outline here a summary of the topics that were discussed, some of the implications, and new directions that are likely to follow from this research. Experimental, theoretical and computational results were presented. The experimental devices and concepts, along with the theory and computational models comprise investigations of fundamental plasma physics, fusion science, and approaches to fusion energy that require magnetized plasmas.     

Computational study on heat transfer and MHD-electrified flow of fractional Maxwell nanofluids suspended with SWCNT and MWCNT

Recent developments in fluid dynamics have been focusing on nanofluids, which preserve significant thermal conductivity properties and magnify heat transport in fluids. Classical nanofluid studies are generally confined to models described by partial differential equations of an integer order, where the memory effect and hereditary properties of materials are neglected. To overcome these downsides, the present work focuses on studying nanofluids with fractional derivatives formed by differential equations with Caputo time derivatives that provide memory effect on nanofluid characteristics. Further, heat transfer enhancement and boundary layer flow of fractional Maxwell nanofluid with single-wall and multiple walls carbon nanotubes are investigated. The Maxwell nanofluid saturates the porous medium. Also, buoyancy, magnetic, electric, and heating effects are considered. Governing continuity, momentum, and energy equations involving Caputo time-fractional derivatives reduced nondimensional forms using suitable dimensionless quantities. Numerical solutions for arising nonlinear problems are developed using finite difference approximation combined with L1 algorithm. The influence of involved physical parameters on flow and heat transfer characteristics is analyzed and depicted graphically. Our simulations found out that surface drag of Maxwell nanofluid with single-walled carbon nanotubes dominates nanofluids with multiple walls carbon nanotubes, but the reverse trend is noticed for larger Grashof number values.     

Current Induced at Conduit Wall by Molten Salt Flowing Across a Magnetic Field

Activation cross sections for mercury isotopes have been measured at neutron energy between 13.4 and 14.9 MeV by means of the activation method using Fusion Neutronics Source (FNS) at Japan Atomic Energy Research Institute (JAERI). Measured cross sections are those of ¹⁹⁶Hg(n, 2n)^195m,^gHg, ¹⁹⁸Hg(n, 2n)^197m,^gHg, ¹⁹⁸Hg(n, p) ¹⁹⁸gAu, ¹⁹⁹Hg(n, p)¹⁹⁹Au, ²⁰⁰Hg(n, p)^200m,gAu, ²⁰¹Hg(n, p)²⁰¹Au, ²⁰²Hg(n, p)²⁰²Au, ²⁰⁴Hg(n, 2n)²⁰³Hg and ²⁰⁴Hg(n, p)²⁰⁴Au reactions. The cross sections of the ²⁰²Hg(n, p)²⁰²Au and ²⁰⁴Hg(n, p)²⁰⁴Au reactions were measured for the first time. For the ¹⁹⁶Hg(n, 2n) ^195m,^gHg, ¹⁹⁸Hg(n, 2n)^197m,^gHg, ¹⁹⁸Hg(n, p)^198gAu and ¹⁹⁹Hg(n, p)¹⁹⁹Au reactions, the cross sections at plural neutron energies were measured for the first time. The present data were compared with the experimental data reported previously and the recent evaluations, and it was shown that some evaluations need to be improved.     

短时间、大功率磁流体发电

介绍了正在发展中的、以炸药或燃烧驱动的等离子体为工质的短时间、大功率磁流体（MHD）发电系统。这是一种脉冲发电系统，可提供几百兆瓦或更高的脉冲功率；也是一种利用电能的新概念火炮的合适能源，具有广阔的军事应用前景。文中还介绍了磁流体发电的基本原理；结合国外的发展现状、动态和我们做过的有关工作，对研制这种脉冲发电系统将会碰到的部分问题作出了评述。     

Analysis of a magnetic field and Hall effects in nanoliquid flow under insertion of dust particles

In this study, the two‐phase hydromagnetic flow of a viscous liquid through a suspension of dust and nanoparticles is considered. The influence of the Hall current is also taken into account. The similarity variables are utilized to transform the problem into one independent variable. The obtained expressions in one independent variable are solved through the Runge–Kutta–Fehlberg scheme connected with the shooting procedure. The computed results are sketched for employing multiple values of physical constraints on the temperature and velocity of the nanofluid and dust phase. The characterization of various nanoparticles like Cu, Al₂O₃, TiO_2, and Ag on velocities and temperatures of both phases is made through plots. A comparative analysis in the limiting approach is presented to justify the present solution methodology. The range of emerging parameters is taken as 0 ≤ l ≤ 3, 0.1 ≤ β_t ≤ 3, 0 ≤ m ≤ 2.5, 0 ≤ M² ≤ 2, 0.1 ≤ β_v ≤ 3, 0 ≤ ? ≤ 0.4, and ?0.8 ≤ λ ≤ 0.8. From the study, it is revealed that β_t has the opposite effect on the temperature of dust and nanofluid phases. The Hall parameter m raises the profiles of velocities in the nanoliquid and dust phases. Also, it is found that the transverse velocities h(η) and H((η) and temperatures θ(η) and θ_p(η) rise for larger ?.