Effects of rare earth on inclusions and corrosion resistance of 10PCuRE weathering steel

The types,morphologies and distributions of nonmetallic inclusions in Cu-P weathering steels with and without rare earth were analyzed through a quantitative image analyzer,scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)attached to SEM.Solid-soluble content of rare earth in the steels was analyzed by non-aqua electroanalysis and ICP.The results showed that rare earth modified the types and the morphologies of inclusions in the weathering steels.The small spherical rare earth oxysulfides and rare earth sulphides replaced the elongated MnS inclusions in the RE weathering steels.The rare earth inclusions dispersedly distributed and most inclusions were smaller than 2 μm in size.The optimum content of RE was 0.0065%-0.016% for 10PCuRE weathering steels containing about0.002% oxygen and 0.004% sulfur.Solid-soluble content of rare earth in steels was(14-20)x 10-6,which can act as a micro-alloying element.The corrosion resistance of 10PCuRE weathering steels and Q235 were studied by dry-wet cyclic immersion test.Their corrosion rates were obtained respectively.The polarization curves and pitting corrosion behaviors of weathering steels with and without rare earth were measured by electrochemical methods.The corrosion resistance of Cu-P weathering steels was improved by adding an appropriate amount of rare earth.Less and fewer rare earth inclusions largely decreased pitting susceptibility and rate of pit propagation.The pitting potential and the resistance against pitting corrosion of the RE weathering steel were significantly improved due to the modification of rare earth to inclusions.     

Lanthanide NIR luminescence for telecommunications, bioanalyses and solar energy conversion

Present-day advanced technologies heavily rely on the exciting magnetic and spectroscopic properties of lanthanide ions. In particular, their ability to generate well-characterized and intense near-infrared (NIR) luminescence is exploited in any modern fiber-optic telecommunication network. In this feature article, we first summarize the whereabouts underlying the design of highly luminescent NIR molecular edifices and materials. We then focus on describing the main trends in three applications related to this spectral range: telecommunications, biosciences, and solar energy conversion. In telecommunications, efforts concentrate presently on getting easily processable polymer-based waveguide amplifiers. Upconversion nanophosphors emitting in the visible after NIR excitation are now ubiquitous in many bioanalyses while their application to bio-imaging is still in its early stages; however, highly sensitive NIR-NIR systems start to be at hand for both in vitro and in vivo imaging, as well as dual probes combining magnetic resonance and optical imaging. Finally, both silicon-based and dye-sensitized solar cells benefit from the downconversion and upconversion capabilities of lanthanide ions to harvest UV and NIR solar light and to boost the overall quantum efficiency of these next-generation devices.     

Evaluation of D113 cation exchange resin for the removal of Eu(Ⅲ) from aqueous solution

Batch adsorption experiments were conducted for the adsorption of Eu(Ⅲ) ions from aqueous solution by D113 resin. The results indicated that D113 resin could adsorb Eu(Ⅲ) ion effectively from aqueous solution. The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH turned from 3.50 to 7.00 and the optimal adsorption condition was in HAc-NaAc medium with pH value of 6.50. The maximum uptake capacity of Eu(Ⅲ) ions was 290.9 mg/g D113 at 298 K, at an initial pH value of 6.50. The overall adsorption process was best described by Lagergren-first-order kinetics. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. The thermodynamic parameters such as free energy (G) which were all negative, indicated that the adsorption of Eu(Ⅲ) ions onto D113 resin was spontaneous and the positive value of enthalpy (H) showed that the adsorption was endothermic in nature. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design. Furthermore, Eu(Ⅲ) could be eluted by using 3.0 mol/L HCl solution and the D113 resin could be regenerated and reused.     

Phase structure and temperature dependent luminescence properties of Sr2LiSiO4F: Eu2+ and Sr2MgSi2O7: Eu2+ phosphors

Green-emitting Sr2LiSiO4F:Eu2+ and blue-emitting Sr2MgSi2O7:Eu2+ phosphors were synthesized by the conventional high temperature solid-state route,respectively.Their structures and photoluminescenee properties were comparatively investigated.It was found that the mixture phases of Sr2MgSi2O7 and SrF2 were obtained when a part of Sr2+ in Sr2LiSiO4F was replaced by some amount of Mg2+ in order to design the possible SrMgLiSiO4F:Eu2+ phosphor.Based on the photoluminescence analysis,Sr2LiSiO4F:Eu2+ phosphor exhibited a green broad emission band of main peak at 513 nm under the excitation of 365 nm,while the Sr2MgSi2O7:Eu2+ and SrMgLiSiO4F:Eu2+ phosphor showed blue emission centered at 467 nm.The temperature dependent photoluminescence properties and room temperature decay time for the three kinds of phosphors were also discussed in this paper.     

Er3+-substituted W-type barium ferrite: preparation and electromagnetic properties

Er3+-substituted W-type barium ferrites Ba1-xErx(Zn0.3Co0.7)2Fe16O27(x=0.00,0.05,0.10,0.15,0.20)were synthesized by polymer adsorbent combustion method.Samples were characterized by X-ray diffraction analysis(XRD),X-ray fluorescence(XRF),scanning electron microscopy(SEM)and network analyzer to investigate the relationships among Er3+concentration,crystal structure,surface mcrphology and electromagnetic properties.All the XRD patterns showed pure phase of W-type barium ferrite when x≤0.15,while the impurity phase of ErFeO3 appeared when x=0.20.The pure W-type barium ferrite showed a hexagonal flake shape.In addition,the microwave electromagnetic properties of samples were analyzed in the frequency range of 2-18 GHz.It was indicated that the electromagnetic properties were significantly improved when Er3+doping content was 0.10.The reasons were also discussed using electromagnetic theory.The optimized ferrite exhibited excellent microwave absoption performance.The maximum of reflection loss(RL)reached about-27.4 dB and RL was below-10dB at the frequency range from 8.4 GHz to 18 GHz,when the thickness was 2.6 mm.     

EXAFS investigation and luminescent properties of nanosized Tb: Lu2O3 phosphors

Nanosized terbium doped Lu2O3 phosphors were synthesized via a modified co-precipitation processing.The as-prepared Tb:Lu2O3 phosphors was consisted of well crystallized nanosized sphere particles with a diameter of about 30 nnx Local structure of Tb ions in Lu2O3 lattice was investigated by an analytical approach based on Fourier transformation of the extended X-ray absorption fine structure(EXAFS) data.X-ray near edge structure (XANES) spectra suggested that all Tb ions doped were tervalonce.EXAFS results indicated that Tb ions have entered the Lu2O3 cubic lattice by means of solid solution.The coordination number and first shell Tb-O distance dropped with the increasing of Tb concentration.Emission spectra of the phosphors was shown to be typical for Tb3+ with main components at 542,550 and 490 nm,derived from irradiative relaxation of 5D4 level.The emission intensity decreased severely with the increasing of Tb concentration from 1 mol.% to 15 tool.%,suggesting a significant concentration quenching above 1 mol.% Tb.The reduction of emission intensity was interpreted by higher distortion derived relaxation among the surface state resident Tb3+ ions.     

Multi-Pass Simulation of Heavy Plate Rolling Including Intermediate Forced Cooling

Thermomechanical Controlled Processing (TMCP) including accelerated cooling after the final hot rolling pass is a well-established technology,widely applied in HSLA steel plate production.However,there are still certain limitations,especially for thicker plate.The rolling schedule includes a long holding period (HP) after the roughing stage to allow the temperature to fall sufficiently for optimised TMCP during finishing.Intermediate Forced Cooling (IFC) applied during the HP can increase productivity by decreasing the required hold time,can restrict austenite grain growth,and can also improve the subsequent strain penetration in thick plate with further metallurgical benefits.Multi-pass plane strain compression (PSC) tests have been performed on the thermomechanical compression (TMC) machine at Sheffield University including different severities of IFC.Clearly it is impossible to simulate all aspects of the temperature and strain gradients present in thick plates in laboratory specimens,and most of the tests were conducted at temperatures and strains calculated by Finite Element modelling as relevant to specific positions through the plate thickness.However,some aspects of the gradients were addressed with tests using cold platens.The results have indeed shown that IFC can shorten the HP and reduce austenite grain growth and its variation across thick plate.     

Overview of Particles and Bubbles in Continuously Cast Steel

This paper gives an overview of phenomena associated with particles and bubbles in continuously cast steel. During steel processing from deoxidation to solidification the inclusion population undergoes changes with opportunities of removal. Flotation is an important separation mechanism. Inclusion particles may accumulate in the solidifying strand, thus forming enriched bands, which depend on the type of casting machine. Bubbles are created during inert gas injection. They also change in size, can float out, but also form accumulation bands. The interaction of bubbles and particles is discussed. Internal structure that recently has been observed on the inner surface of bubbles will be reviewed.     

烦恼 快乐 艺术——池莉“人生三部曲”解读

池莉的"人生三部曲"--<烦恼人生>、<不谈爱情>、<太阳出世>诉尽了普普通通的市民烦恼,小说中主人公被柴米油盐、吃喝拉撒、老婆孩子等琐事所烦着,从而构成他们的"烦恼人生".然而池莉通过自己的艺术创作,以积极的人生态度,又让读者体会到生活本身的快乐,"烦恼人生"中包含着"快乐人生".     

属性块在工程图形中的研究与应用

介绍了在工程图形中用属性块标注表面粗糙度的方法.采用属性块不仅能避免大量重复性的工作,还能节省大量的存储空间,具有提高绘图速度、质量,便于修改,资源共享等应用价值.     

气驱排渗技术及其在膏体尾矿筑坝工程的应用

果郎沟尾矿库为甲玛铜多金属矿二期工程配套尾矿库,采用初期坝+膏体上游法堆坝形式,实际运行过程中存在尾砂渗透系数低、不固结,且坝体浸润线埋深仅10 m左右等问题.华泰龙矿业公司采用气驱排渗技术,在坝体均匀布设特殊结构的竖直和水平排渗管,采用高压气驱和重力自流的联合排渗方式,大大提高了坝体排渗效率,浸润线埋深快速降低至20...     

德兴铜矿2#尾矿坝透镜体的分形特性研究

透镜体的分布反映了尾矿堆积坝的沉积状况,对尾矿坝的稳定有重要影响,对江西铜业公司德兴铜矿2＃尾矿坝主剖面的透镜体进行盒维数分析,表明透镜体分布存在分形特性,分形维数为1．5024。     

某钨矿尾矿库坝体渗水治理实践

某钨矿尾矿库坝体渗水严重,存在很大的安全隐患。通过对尾矿库岩土工程地质特征、土层渗透性、坝体渗流计算分析以及初期坝坝坡渗水原因分析,提出在初期坝坝面和排渗棱体顶部各增设一排水平排渗管,将坝体内尾矿渗透水及时引至坝坡排水沟后再排往下游,降低坝体内浸润线,以增强坝体稳定性。治理后初期坝坝面水平排渗管日最大排渗量696 m3,排渗棱体顶部水平排渗管日最大排渗量1 326 m3,解决了坝坡渗水问题,标高200 m浸润线比治理前降低了0.99 m,保证了坝体的稳定与安全。     

排渗墙技术及排渗效果分析

对于初期坝为土坝的的尾矿库,后期随着尾矿的堆高,很容易造成坝坡渗水。现有的排渗设施———盲沟、管井、轻型井点、水平滤水孔、辐射井等可以起到一定效果,但不能大面积截断浸润线流线,没有解决悬挂水的影响,降水深度也不够理想。结合现有排渗措施提出排渗墙技术,经过工程实践表明,其有效性和可靠性均大幅提高。     

申家峪尾矿库三维渗流稳定分析与研究

为确保申家峪尾矿库坝体的安全稳定,根据尾矿库工程地质和水文地质的实际情况,对申家峪尾矿库的渗流条件进行了符合实际情况的假设,并建立了反映主要坝体结构和周边岩体特性的三维有限元模型。通过MIDAS/GTS NX计算软件的数值模拟,分析了尾矿坝终期标高340 m时正常工况下坝体的渗流特性和正常运行条件下的渗流情形;评价分析了尾矿库在终期堆积标高时的渗流稳定性,并为坝体抗滑稳定验算提供了准确的浸润面位置。通过工程分析证明,利用MIDAS/GTS NX计算软件可以较好地模拟尾矿库的渗流特性,对尾矿库的安全生产有一定的参考价值和指导意义。     

德兴铜矿尾矿库“头顶库”隐患治理

为贯彻落实国家安监部门发布的尾矿库“头顶库”隐患治理文件的要求，在充分分析德兴铜矿尾矿库“头顶库”特点的基础上，结合“头顶库”综合治理措施方法，制定了尾矿库“头顶库”治理方案，治理效果显著，消除了“头顶库”安全隐患，为全国尾矿库“头顶库”治理提供了经验参考。     

德兴铜矿尾矿库“头顶库”隐患治理

为贯彻落实国家安监部门发布的尾矿库"头顶库"隐患治理文件的要求,在充分分析德兴铜矿尾矿库"头顶库"特点的基础上,结合"头顶库"综合治理措施方法,制定了尾矿库"头顶库"治理方案,治理效果显著,消除了"头顶库"安全隐患,为全国尾矿库"头顶库"治理提供了经验参考。     

大尹格庄金矿尾矿库扩容工程实践

基于大尹格庄金矿尾矿库加高扩容的工程实践,介绍了尾矿库基本系统的主要构成,分析了尾矿库排洪系统的可靠性,并通过浸润线指标的控制对尾矿库稳定性进行了评价。     

某尾矿库坝体稳定性分析

针对某尾矿库的现状,在现场调查的基础上,分析了尾矿初期坝和堆积坝坝体的组成结构,开展了尾矿工程特性研究和不同情况下的坝体稳定性研究,并探讨了坝体的灾害防治措施。研究结果表明：从放矿口至库内尾矿粒径由大变小,堆积尾矿由东向西整体上有西粗东细的特征;选取瑞典圆弧法、毕肖普法等对上游法尾矿库堆积坝稳定性进行分析比较,运用数值分析方法计算各种情况下尾矿坝的安全系数均大于1.25。为了保证坝体安全系数满足规范要求,必须保证坝体排渗设施安全有效运行,及时降低坝体浸润线高度。基于安全考虑,可依靠增加坝体自重和降低库内水位来减小坝体的滑坡风险。该研究成果能为尾矿库的灾害防治提供理论依据。     

浅谈上游式尾矿库闭库治理措施

结合上游式尾矿库特点,分析上游式尾矿库运行常见问题及相应闭库治理措施,并以某尾矿库闭库治理为例,说明尾矿库闭库最基本的治理措施应包括尾矿坝治理措施、排洪系统治理措施和监测设施治理措施,且应根据尾矿库的具体情况进行针对性的治理,使尾矿库闭库后保持长期稳定.