Results of the Inner Electrode Modification on the ZaP Flow Z-Pinch

The ZaP Flow Z-Pinch is a basic plasma physics experiment that uses sheared flows to stabilize an otherwise unstable configuration. The inner electrode is replaced with a larger version (15 cm diameter presently versus 10 cm previously). The goal of this modification is to increase temperature through increased adiabatic compression and to allow greater flexibility of neutral-gas injection through a greater number of gas-puff valves. Results are presented regarding the effect of neutral-gas injection characteristics and charge voltage on pinch stability. Increasing capacitor bank voltage and mass of gas injected increases stability and proximity to the machine axis. A four-chord HeNe interferometer is used to determine density at z = 0 cm and total temperature using magnetic field information from the z = 0 azimuthal array of magnetic probes. Total temperatures of 100–150 eV and densities of 2–3 × 10²² m⁻³ are calculated; temperatures are consistent with measured electron and ion temperatures.     

Design and performance analysis of ITER ex-vessel magnetic diagnostics

Accurate magnetic diagnostics are essential to perform reliable operation of any tokamak. The ITER magnetic diagnostics include a wide variety of sensors located on the inner and outer surfaces of the vacuum vessel, in the divertor cassettes and in the casing of the toroidal field coils. As the measurement accuracy of the inner set of magnetic sensors might be compromised by various radiation effects and high heat loads, the complementary ex-vessel set is essential to provide backup information. This paper is an overview of the ex-vessel magnetic diagnostic which consists mainly of pick-up coils, steady state sensors, Rogowski coils in the toroidal field coil casing and fibre optic current sensors. The work presented aims at designing these sensors to meet the performance requirements in spite of the constraints due to the tokamak environment. The manufacturing constraints and the positioning requirements for all the ex-vessel magnetic sensors are described. The use and expected accuracy of the entire ex-vessel magnetic diagnostic is assessed in terms of magnetic equilibrium reconstruction and plasma current measurement precision.     

Structural,dielectric and ferromagnetic behavior of (Zn,Co) co-doped SnO2 nanoparticles

Nanoparticles of basic composition Sn_0.94Zn_0.05Co_0.01O₂, Sn_0.92Zn_0.05Co_0.03O₂ and Sn_0.90Zn_0.05Co_0.05O₂ were synthesized by chemical precipitation method. The incorporation of Co and Zn in SnO₂ lattice introduced significant changes in the physical properties of all the three nanocrystals. The average particle size estimated from TEM data decreased from 15.71 to 6.41  nm with enhancement in concentration of oxygen vacancies as Co content is increased from 1 to 5 wt%. Increasing Co content enhanced the Sn:O atomic ratio as a result concentration of oxygen vacancies increased. The dielectric study revealed strong doping dependence. The dielectric parameters (ε′, tanδ and σ_ac) increased with increasing Co content and attained maximum values for 5% (Zn, Co) co-doped SnO₂ nanoparticles. The dielectric loss (ε′′) exhibited dispersion behavior and the Debye’s relaxation peaks observed in dielectric loss factor (tanδ), whose intensities increased with increasing Co content. The variation of dielectric properties and ac conductivity revealed that the dispersion is due to Maxwell-Wagner interfacial polarization and hopping of charge carriers between Sn⁺²/Sn⁺³ and Co⁺²/Co⁺³. The large dielectric constant of all samples made them interesting materials for device application. Magnetization measurements (M (H) loops) revealed enhancement in saturation magnetization with doping which is due to the formation of large amount of induced defects and oxygen vacancies in the samples. The present study clearly reveals doping dependent properties and the oxygen vacancies induced ferromagnetism in Zn, Co co-doped SnO₂ nanoparticles having applications in ultra-high dielectric materials, high frequency devices and spintronics.     

磁力传动齿轮泵结构设计及分析

针对系统要求,为使齿轮泵达到高可靠性、零泄漏的要求,设计一种特殊的齿轮泵结构。采用磁力传动使齿轮泵和电机以非接触式进行连接,取消了传统结构上的轴封,摩擦力小,使电机的输入功率减少;将动密封转换为静密封,使该齿轮泵实现零泄漏的指标。     

Interactive visualization of three-dimensional magnetic fields

In order to observe the physical values (magnetic flux density and eddy current) in 3D magnetic field analysis, an interactive and highly manipulative visualization system depicting stereo images is intalled in a graphics workstation with high functional graphic processors. The system has the following characteristics:

• 1 An interactive and highly manipulative menu window with many functions: it enables visualization of complex phenomena in a 3D field through observation of various combinations of physical values from various viewpoints.
• 2 Simultaneous display of both magnetic flux density and eddy current by using the appropriate use of two colour display methods for stream lines and distribution maps of density: this function facilitates observation of the mutual relations between two physical values in a 3D field.
• 3 Animations and stereo displays: since they give extremely distinct images, observers can easily understand even highly complex 3D phenomena.

In this paper, the calculation method of density vectors, their display methods, and interactive functions are described. Some examples are also illustrated.     

Cobalt-Containing Hyperbranched Poly(silylenearylene)s

A group of hyperbranched poly(silylenearylene)s are synthesized by homopolycyclotrimerizations of A₂-type silylenediynes. The polymers can be readily metallized by complexations of their periphery triple bonds with cobalt octacarbonyls Co₂(CO)₈. Pyrolysis of these organometallic polymers gives magnetic ceramics in good yields. Analyses by SEM, TEM, XPS, EDX, and XRD demonstrate that the ceramics comprise ferromagnetic Co and paramagnetic Co₂Si nanocrystallites wrapped by carboneous shell. The ceramics show high magnetic susceptibilities (M _s up to ~50 emu/g) and near-zero coercivity (H _c down to ~0.14 kOe), suggesting that they are good soft magnetic materials with low hysteresis loss. This article was to be included in the March issue of Volume 19, which was dedicated to Professor Takakazu Yamamoto. The journal editors sincerely apologize for the omission and delay in publication for which the authors and the guest editor bare no responsibility. M. Zeldin and A. S. Abd-El-Aziz, Editors.     

攀枝花微细粒级(-19μm)钛铁矿回收探索试验

通过对攀枝花微细粒级 (- 19μm)物料性质的研究 ,提出了回收钛铁矿的方法 ,并选择不同浮选药剂进行了选矿实验室试验。试验结果表明 ,采用强磁 +浮选工艺流程能够回收攀枝花微细粒级 (- 19μm)钛铁矿     

恒星光干涉仪中光学延迟线的结构设计

下一代长基线恒星光干涉仪要求光学延迟线在快速移动时,保持光程差在纳米级.在恒星移动,大气扰动和机械振动的情况下,恒星光干涉仪的光学延迟线要求实时补偿从观测星到光束合成器的光程差.为此提出光学延迟线的一些改进方案.     

磁流变双筒式液压减振器设计及磁路仿真研究

介绍了某装甲车辆用被动式双筒式液压减振器的基本结构,基于这种结构提出了两种磁流变双筒式液压减振器的结构设计方案.为了确定最优的设计方案,利用Ansofi工程电磁场有限元分析软件对两种不同结构的MRF双筒式液压减振器的磁路进行了有限元分析.使用车载电源,在相同的工作电流下仿真得到两种结构该型MRF双筒式液压减振器的磁感应强度矢量和磁场强度分布,为其在车辆悬挂系统半主动控制中的应用奠定了基础.     

白云鄂博主东矿中贫氧化矿铌资源的特点及综合回收

包头白云鄂博主东矿中贫氧化矿中铌有很大的回收价值,本文探讨了主要铌矿物的特点及选矿性质,认为弱磁—强磁是初步富集铌的有效途径。本文还较为详细地介绍了从强磁中矿的稀土浮选尾矿回收铌得到富铌铁精矿的若干浮选工艺条件及浮选药剂。