Playback performance of perpendicular magnetic recording tape media for over-50-TB cartridge by facing targets sputtering method

Perpendicular magnetic recording tape medium with laminated soft magnetic underlayers was successively formed on a 4.5 μm thin plastic film by the facing targets sputtering method at room temperature. The tape medium showed extremely high SNR values with sharp transitions in playback tests by a drum tester, compared to a linear format commercial tape medium. An areal density of 45.0 Gb/in.² of perpendicular tape medium was confirmed by a high-resolution contact tester. These results suggest that the perpendicular recording tape medium by the facing targets sputtering method is a promising candidate for a tape cartridge of over 50-TB.     

单晶热释电探测器混合集成制造方法研究

在比较几种探测器集成制造方法的基础上,提出采用各向异性导电膜作为电信号互联的手段,实现热释电探测器与信号处理电路的混合集成,从而演示了一种兼容性良好的集成化多传感器制造方法.对单晶钽酸锂热释电探测器采取机械研磨减薄获得其薄膜,利用3M的5552R各向异性导电膜,实现了探测器与信号读出电路的互联.对探测器的测试表明:机械研磨减薄获得的钽酸锂薄膜表现出与晶体接近的热释电特性,探测器表现出良好的绝热性质和动态响应特性.     

Microstructure evolution of WC/steel composite by laser surface re-melting

WC/steel composites fabricated by electro-slag melting and casting were re-melted by transverse flow CO₂ laser. Optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and transmission electron microscopy were used to analyze the microstructure evolution in laser melted layer. It was found that the laser-affected zone has three distinguished zones, the melted, transient and heat affected zone. The phases of the melted zone were composed of WC, Fe₃W₃C, (Cr,Fe)₇C₃, martensite and retained austenite. The microstructure evolution in the melted zone was represented by the transformation of three parts including the steel matrix, WC particles cluster and dispersed carbides. A significant reactant was herringbone eutectic carbide of Fe₃W₃C. The effect of laser scanning rate was mainly behaved in affecting the melt depth, microstructure of transient zone and dissolution of medium carbides. In comparison with the substrate, the melted zone has much higher microhardness.     

Generation of hard X-ray radiation using the triboelectric effect by peeling adhesive tape

The triboelectric effect describes electrical charging when bringing different materials into contact. We report on the generation of hard X-ray radiation by peeling various adhesive tapes under medium vacuum conditions. Beside vacuum housing and pumps as instrumentation only an electric motor, two rolls and a metal foil as target material are necessary. The spectral distribution of generated X-rays was analyzed using an energy-dispersive detector. Depending on peeling speed, pressure and choice of material combination, electrons with energies sufficient to excite emission in the hard X-ray region are produced. The results are discussed in terms of triboelectric separation of charge carriers.     

中药微量元素含量区间尺最佳分级问题的探讨

在深入研究中药微量元素含量区间尺的基础上，从统计学角度对区间尺的最佳分级问题作了详细探讨，提出用5级区间尺来衡量中药中不同元素含量间相对高低水平，理论上更合理。     

New ceramic microfiltration membranes from mineral coal fly ash

This work aims to develop a new mineral porous tubular membrane based on mineral coal fly ash. Finely ground mineral coal powder was calcinated at 700 °C for about 3 h. The elaboration of the mesoporous layer was performed by the slip casting method using a suspension made of the mixture of fly ash powder, water and PVA. The obtained membrane was submitted to a thermal treatment which consists in drying at room temperature for 24 h then a sintering at 800 °C. SEM photographs indicated that the membrane surface was homogeneous and did not present any macro defects (cracks, etc.). The average pore diameter of the active layer was 0.25 μm and the thickness was around 20 μm. The membrane permeability was 475 l/h m² bar.This membrane was applied to the treatment of the dying effluents generated by the washing baths in the textile industry. The performances in term of permeate flux and efficiency were determined and compared to those obtained using a commercial alumina microfiltration membrane. Almost the same stabilised permeate flux was obtained (about 100 l/h m²). The quality of permeate was almost the same with the two membranes: the COD and color removal was 75% and 90%, respectively.     

Influence of chitosan and epoxy cross-linking on physical properties of binary blends

In this study, blends of chitosan (Cs) and bisphenol-F-diglycidyl ether (3.80 × 10^?3 to 3.80 × 10^?2 mol) were cast by the solution route. FT-IR results suggested that chitosan was cross-linked at terminal amino groups through diepoxide linkage. The chitosan films became less flexible and stiffer upon reaction with epoxy. Blending improved percentage elongation (31%) and toughness (10 MPa), whereas Young’s modulus (145 MPa) and tensile strength (45 MPa) were decreased. Extent of weight loss in Cs/BPFDGE was lower (15%) than that of original precursors (chitosan 33%). Moreover, blending of chitosan with BPFDGE increased water absorption properties due to generation of hydrophilic ?OH groups.     

双合金结合速凝工艺制备烧结NdFeB研究

采用速凝工艺制备了主相合金铸片,由其微观形貌分析可见,富Nd相呈薄层状均匀分布在主相晶界处。XRD分析表明铸带形成了明显的取向织构。使用普通熔炼方法熔炼几种不同成分的辅相合金。将主相合金与辅相合金配比,运用双合金法工艺制备出烧结NdFeB磁体。研究表明Pr替代Nd有利于提高磁体的剩磁。     

Untersuchung von Strömungs- und Erstarrungsvorgängen beim kontinuierlichen Aluminiumguß

Beim Breitbandgießwalzen von Aluminium (Hunter-Anlage) und beim Gießwalzen von Schmalband (Rotary-Anlage) wurden Untersuchungen mit dem Radioisotop ¹⁹⁸Au durchgeführt, deren Ziel die qualitative und quantitative Verbesserung der Produktion von Aluminiumhalbzeugen auf diesen Anlagen war. Es wird gezeigt, daß das autoradiographische Verfahren eine geeignete Methode ist, um Probleme wie die optimale Gestaltung des Gießtraktes oder die Ermittlung der günstigslen Gießparameter zu lösen. Eine Gegenüberstellung von Autoradiogrammen und metallographischen Darstellungen zeigt, daß auch strukturelle Unterschiede im Metallgefüge mit Hilfe der Autoradiogramme besser interpretiert werden können und sich somit die Aussagekraft derartiger Untersuchungen erhöht.