超大型超细卧式砂磨机的突破创新及其在矿山之应用

纳米科技是本世纪科技发展的重要技术领域,势必创造另一波技术创新及产业革命。卧式砂磨机是一种高效率的超细湿法研磨设备。本文介绍了新型卧式砂磨机设备结构、工艺及其在工业矿物中的应用情况。不论其应用领域为何,所需要用的材料均为次微米或纳米级尺度之材料。如何得到纳米级粉体及如何将纳米级材料分散到其最终产品已成为目前产﹑经及学术界共同之研究课题。本文将针对纳米粉体研磨及纳米材料分散到其最终产品技术加以详加探讨,系统介绍卧式砂磨机在金属矿山的应用情况和最新研究进展,及对金属矿山资源综合利用和节能降耗的贡献,并对此进行了综合评述和发展展望。     

Magnetizing of permanent magnets using HTS bulk magnets

A demagnetized Nd–Fe–B permanent magnet was scanned just above the magnetic pole which contains the HTS bulk magnet generating a magnetic field of 3.27 T. The magnet sample was subsequently found to be fully magnetized in the open space of the static magnetic fields. We examined the magnetic field distributions when the magnetic poles were scanned twice to activate the magnet plate inversely with various overlap distances between the tracks of the bulk magnet. The magnetic field of the “rewritten” magnet reached the values of the magnetically saturated region of the material, showing steep gradients at the border of each magnetic pole. As a replacement for conventional pulse field magnetizing methods, this technique is proposed to expand the degree of freedom in the design of electromagnetic devices, and is proposed as a novel practical method for magnetizing rare-earth magnets, which have excellent magnetic performance and require intense fields of more than 3 T to be activated.     

一种检测乳化炸药及其基质密度的简便方法

文章在分析常用乳化炸药、乳化炸药基质密度测定方法的基础上,提出了一种基于阿基米德定律检测乳化炸药及其基质密度的方法及仪器。使用该方法及仪器可以大大缩短检测周期和提高检测结果的准确度。经测试和比较,乳化基质密度检测周期可由原来的358s缩短至20s,检测结果的绝对误差和均方值由原来的0．0019g/cm3、6．50E。降低至0．0005g／cm3、3．82E-6,应用这种方法和仪器还可以提高工作效率、减少工作量和生产线工作定员。     

基于BP神经网络的充填料浆流变参数预测分析

为了合理分析充填料浆在长距离管道中的输送阻力,基于流变参数对输配管网设计的重要性,在全面评估不同因素对流变性能影响的程度后,采用BP神经网络原理,建立起干料中水泥含量X1、料浆浓度X2、料浆坍落度X3、料浆容重X4对流变参数(屈服应力Y1、粘性系数Y2)影响的函数模型.此BP网络为4-Hn-2结构,隐层和输出层分别用tansig、purelin函数传递,利用Levenberg-Marquardt优化算法trainlm训练网格.计算结果表明:该模型在预测充填料浆屈服应力Y1和粘性系数Y2中适应性较强,误差也在可控范围之内,可为充填管网布设及输配系统沿程阻力分析提供可靠依据.     

Coagulation and precipitation of a mechanical pulping effluent—I. Removal of carbon,colour and turbidity

This study examined the effects of metal coagulant concentration, effluent dilution and pH on the removal of total carbon, colour and turbidity from a combined bleached chemithermomechanical/thermomechanical (BCTMP/TMP) effluent. Both chloride and sulphate salts of iron and aluminum were effective in treating the mechanical pulping effluent in batch jar screening tests. pH had a pronounced affect on precipitation. In terms of minimizing the total carbon (TC), colour and turbidity levels, the optimum adjusted pH ranges were: 4.0–6.5 for ferric chloride, above 7.4 for ferrous sulphate, 5.0–6.0 for aluminum chloride and 5.8 to 6.8 for aluminum sulphate. Removal of TC, colour and turbidity of up to 88, 90 and 98%, respectively, were observed. The precipitation yielded a supernatant which was virtually clear and colourless.     

Multi-colored quadtrees for GIS: Exploiting bit-parallelism for rapid boolean overlay

A number of tesselation based GIS using quadtrees as the underlying data structure have been constructed in recent years. At present there is an almost universal trend towards the representation of a thematic layer as a collection of binary, linear quadtrees, one for each color (value) in the layer. In such a scheme set operations are carried out by taking unions and intersections of binary quadtrees. This paper presents an alternative database scheme where a layer is stored as a single multicolored quadtree, using a bit-list to store values at higher nodes in the tree. This allows the union of any set of values within a layer to be carried out by a single top down traversal of the tree, using parallel bit-masking operations. Experimental evidence is presented to show that these Bit-Mapped Multi-Colored quadtrees lead to faster colour selection and boolean overlay between layers in a GIS. Furthermore, the recent development of One-To-Four and Autumnal quadtrees have meant that it is now possible to exploit the hierarchical structure of regular quadtrees in GIS without paying an associated storage penalty. Experimental results using these developments are presented to show that representing a layer using a Bit-Mapped Multi-Colored quadtree is more space and time efficient for set operations in comparison to the use of a collection of binary quadtrees, one for each value in the layer.     

Enhancement of catalytic activity of Raney nickel by cobalt addition

The effects of cobalt as a promoter of the catalytic activity of Raney nickel for various manufacturing esses have been studied. The variation of particle size distribution, specific surface area and residual aluminium content can also affect the catalytic properties of Raney nickel. The characteristics of the catalyst are considerably influenced by the relative nickel and aluminium contents. When the catalysts are prepared from 60 wt.% nickel and 40 wt.% aluminium, the electrode performance shows the highest current density of 450 mA/cm². With the addition of cobalt, the particle size is diminished from 13.92 to 11.70 μm and the decrease of the particle size contributes to a slight enlargement of the specific surface area. The mass activity of a hydrogen electrode manufactured with cobalt Raney nickel in alkaline solution is increased from 3.74 to 4.03 A/g when 120 mg/cm² of catalyst are loaded in the electrode.     

The electronic structure,site occupancy and luminescent properties of Ce3+-activated Li2Ca2Si2O7 blue phosphor

Rare earth activated lithium-containing alkaline earth silicates is an intensely studied topic in the fields of luminescent materials. In this study, a cerium-activated lithium-silicate blue phosphor, Li₂Ca₂Si₂O₇:Ce³⁺, was explored using structural computational simulations and systematic experiments. The Li₂Ca₂Si₂O₇:Ce³⁺ phosphor can be efficiently excited by near-ultraviolet and cathode ray light sources. According to the spectroscopic redshift theory, time-resolved photoluminescence (TRPL) and cathodoluminescence (CL) spectra, it is determined that the broad emission of Li₂Ca₂Si₂O₇:Ce³⁺ comes from two different luminescent centers. In addition, Li₂Ca₂Si₂O₇:Ce³⁺ exhibits strong blue emission at ~415 nm with high quantum yield and stable emission under high temperature and continuous electron beam bombardment. Therefore, this study provides a new insight into developing new high-efficiency and high-purity trichromatic phosphors.     

Zn0.5Cd0.5S@Ni(OH)2可见光下光催化制氢性能研究

采用水热法制备了Zn_0.5Cd_0.5S纳米片状光催化剂,并通过沉淀法原位负载Ni(OH)₂,制备出光催化剂Zn_0.5Cd_0.5S@Ni(OH)₂。Zn_0.5Cd_0.5S异质结有着良好的光吸收性能,负载Ni(OH)₂能为催化剂提供大量反应活性中心,有效减少了光生载流子的复合,能大幅度提高产氢速率。实验结果表明,当Ni(OH)₂负载量为15%时,光催化剂产氢性能达到最佳,在可见光(λ≥420 nm)照射下,其平均产氢速率为44.46 mmol/(g·h),是未负载Ni(OH)₂基体材料的5.3倍。