Thermal and radiative characteristics of oxyfluoride glass singly doped with lanthanide ions

Rare earths-doped oxyfluoride glasses based on germanium oxide and lead fluoride were prepared from commercial raw materials. The glasses with general composition of 50GeO2-(50-x-y)PbO-yPbF2-xLnF3 (Ln=Pr3+-Yb3+), contained different concentrations of optically active dopants (x=0.2 mol.% and 2 mol.%) and PbF2 (y≤15 mol.%). The differential thermal analysis (DTA) was used to determine both thermal characteristic and thermal stability properties of the glasses in the function of the kind of dopant, its concentration, and a glass composition. Characteristic glass temperatures such as glass transition temperature (Tg), glass crystallization temperature (Tc) and temperature corresponding to the maximum of the crystallization rate (Tpc) were evaluated. On the basis of obtained results, the thermal stabilities of glasses under study were evaluated using various thermal stability criteria (Dietzel factor ?T, Saad-Poulain factors H' and S). It was found that the increase in rare earth fluoride contents influenced thermal characteristics when the characteristic temperatures of the individual glass was shifted towards higher values. The effect of the PbF2 content and the kind of rare earth impurity on the glass stability was observed. Absorption spectra of lanthanide-doped glasses were measured at room temperature and used to determine the phenomenological intensity parameters Ωt and next, to estimate radiative properties of lanthanide ions in this matrix. Radiative transition probabilities of luminescent states of Ln3+, branching ratios and radiative lifetimes were determined. The variation of the Ωt along the lanthanide series was presented and discussed.     

Process optimization of electroless copper plating and its influence on electrochemical properties of AB5-type hydrogen storage alloy

The amount of Cu coating by chemical plating was investigated based on quadratic regression orthogonal experimental design being adapted to the variation law of temperature,pH value and Ni2+concentration,and the relevant regression equation was expressed as y=2.1609+0.5295×10-3T2-0.0342P2-0.0265N2+0.0023TP+0.0020TH+0.0199PN-0.0959T+0.3814P-0.2073N.The results showed that the deposition rate augmented with the increasing in temperature,pH value and Ni2+concentration.The experimental parameters of the optimal coating were temperature 75 ℃,pH value 8.5 and Ni2+concentration 1.2 g/L.The electrochemical tests indicated that the cycle stability increased from 60.66% to 75.58%,indicating that the treated alloy exhibited better corrosion resistance.     

天铁热力风机升级改造方案设计

通过对天铁集团高炉现状、风机现状的分析,提出了对热力厂风机升级改造的规划,确定了实施方案.该方案实施后将彻底改变风机渐进式改造的现象,使新高炉的备用机组发挥更大的作用,可增加现有高炉的风压、风量,使现有高炉的产量、冶炼强度进一步提高.     

Recent progress report on DNA B-Z transition modulated by rare earth-amino acid complex and Alzheimer's disease amyloid beta

Rare earth dements have unique physical, magnetic, luminescent and catalytic properties. They have been successfully used as medicine and probes in luminescent resonance energy transfer (LRET) for bioassays, as well as reagents for diagnosis in magnetic resonance imaging (MRI). In this progress report, we will focus on recent progress on how rare earth amino complexes bind to DNA and change DNA structure, especially on DNA B-Z transition induced by rare earth amino acid complex and its potential impact on Alzheimer's disease (AD).     

Numerical Simulation on Inclusion and Bubble Entrapment in Solidified Shell in Model Experiment and in Mold of Continuous Caster With DC Magnetic Field

A model experiment investigating entrapment of inclusions and bubbles on the solidified shell was performed using molten steel,and the conditions for inclusion and bubble entrapment and mechanism of entrapment were studied.The results were applied to the flow behavior in the casting mold of a continuous caster.At the solid-liquid interface,entrapment of inclusions is greatly reduced by the existence of a low velocity flow,e.g.,0.05m/s.The above-mentioned interfacial flow velocity dependency of inclusion entrapment is considered to be largely influenced by changes in the thickness of the concentration boundary layer,which depend on the interfacial flow velocity.Specifically,bubbles and inclusions which enter the concentration boundary layer are drawn to the solid-liquid interface by a suction force which is several orders larger than the Saffman’s force.In addition to the above-mentioned suction force,the so-called cleaning effect is determined by fluid-dynamic forces such as drag force,etc.which act on particles,and furthermore,by resident time of particles at the solid-liquid interface,which depends on the solidification rate.In a FC mold with a 2-stage electromagnetic brake,flotation of bubbles entrained in the jet flow from the nozzle is accelerated with the large DC magnetic field.This is attributed to the braking effect of the DC field on the nozzle jet and the upward flow by the buoyancy of the bubbles.As a result,the interfacial flow velocity can be normalized by increasing the strength of the magnetic field,and entrapment of large bubbles and inclusions can be reduced.     

Influence of Controlled Rolling and Cooling Process on the Mechanical Properties of Low Carbon Cold Forging Steel

In the present paper,controlled rolling and cooling processing was conducted by using a laboratory hot rolling mill.The influence of different processing parameters on the mechanical properties of low carbon cold forging steel was investigated.The results show that the faster cooling after the deformation (especially in low temperature rolling conditions) leads to the refinement of the ferrite grain.The specimen exhibits very good mechanical properties owing to the finer ferrite grains.The pearlite morphologies can also affect the mechanical properties of low carbon cold forging steel.The mechanical properties increase with decreasing final cooling temperature within the range from 650℃ to 570 ℃ due to the finer interlamellar spacing of pearlite colony.The mechanical properties of the specimens with fast cooling after the conventional rolling are not only better than those of the specimens with slow cooling after low temperature rolling,but also almost similar to those of the specimens with fast cooling after low temperature rolling.It is suggested that fast cooling after high temperature rolling (the conventional rolling) process would be of important industrial value.     

The LIMMCAST Program at HZDR:Modelling of Fluid Flow and Transport Phenomena in the Continuous Casting Process

Model experiments with low melting point liquid metals are an important tool to investigate the flow structure and related transport processes in melt flows relevant for metallurgical applications.We present the new experimental facility LIMMCAST for modelling the continuous casting process of steel using the alloy SnBi at temperatures of200-400℃.The parameters of the facility and the dimensions of the test sections will be given,and the possibilities for flow investigations in tundish,submerged entry nozzle and mould will be discussed.In addition,the smaller set-up Mini-LIMMCAST will be presented,which works with the room-temperature liquid alloy GaInSn.The main value of cold metal laboratory experiments consists in the capabilities to obtain quantitative flow measurements with a reasonable spatial and temporal resolution.New ultrasonic and electromagnetic techniques for measuring the velocity in liquid metal flows came up during the last decade allowing for a satisfying characterisation of flow quantities in the considered temperature range up to 400℃.First results from LIMMCAST and Mini-LIMMCAST will be presented covering the following phenomena:fully contacfless electromagnetic tomography of the flow in the mould,flow monitoring by a multitude of ultrasonic sensors,and analysis of the flow in the mould under the influence of an electromagnetic brake:intensification of the flow turbulence contrary to the expected flow damping,injection of argon bubbles through the stopper rod:occurrence of pressure oscillations.     

汽车零件强度、寿命与可靠性分析与模型

The elasto-plastic stress/strain behavior of an automobile rear axle was analyzed by three-dimension finite element method.Based on the stress in critical area where fatigue crack appears,the fatigue life of the welded structure was predicted using the critical shear stress plane criterion.To improve the fatigue property of the rear-axle,the welding-seam was strengthened by both pellet spraying and plasma melting,and evident improvement was experimentally illustrated.Based on the viewpoint that a complex component is also a system in the respect of reliability assessment and statistical dependence among component failures(i.e.the so call"common cause failure")is inherent for system under stochastic load environment,a system-level load-strength interference model was presented and the reliability of the rear axle was estimated as a system,instead of a component.     

铝土矿、氧化铝和电解铝产业链市场及利润流向

本文主要介绍近几年铝土矿、氧化铝和电解铝产业链的市场和利润流向演变以及未来发展形势.     

提高轧制重轨BS75A成材率的措施

介绍了武钢大型厂生产重轨BS75A时,利用现有设备,通过不断研究,找到了一条提高重轨(BS75A)生产成材率的方法,并取得了较好的经济效益.     

矿用扇风机选型的专家系统

矿用扇风机选型的专家系统能根据矿山实际生产情况和安全技术的要求 ,应用人工智能原理 ,选出最优的扇风机 ,选出的扇风机能适应井下生产条件的动态变化 ,它为矿用扇风机的选型提供了一种新的方法     

炉卷轧机轧辊磨损与辊型设计探讨

通过对轧辊磨损模型的分析,探讨了适合本生产线的轧辊磨损回归模型,初步介绍了轧辊磨损模型的解析原理,在分析轧辊磨损状态的基础上初步解析设计轧辊辊型的原则和方法.     

构建学习型企业 增强创新能力

在市场竞争日趋激烈的新形势下，企业唯一持久的竞争优势就是比竞争对手学习得更快，做得更好，充满活力，勇于创新。而构建学习型企业，已成为企业提高职工整体素质，不断增强创新能力的重要手段。     

冶炼烟尘比电阻与电除尘器效率的关系

本文分析了冶炼过程烟气比电阻与电除尘效率的关系，提出了降低比电阻以提高除尘效率的主要措施。     

珠钢CSP生产线中机架零调问题的解决

对机架不能零调的原因进行了分析，提出了解决机架零调问题的方法。     

浅议工程项目竣工后的财务会计管理

工程项目峻工后 ,按照项目法施工管理要求工程项目经理部需办完清欠交接后撤销。在清欠交接过程中财务管理上要精心组织 ,各部门要各司其职相互监督协调 ,并安排具体负责人员 ,使收尾工作完满、清楚     

影响进口铜精矿质量的因素分析

本文通过对进口铜精矿的质量跟踪 ,提出了影响进口铜精矿质量的因素 ,并对相关质量指标进行了全面的分析 ,找到了原因所在 ,提出了措施和对策     

工业废弃物的多途径应用及效果分析

在钢铁冶金生产过程中会产生大量工业废弃物，而且其存在形态各不相同，既污染环境，又造成资源浪费。阐述了如何根据各种废弃物不同的形态，采取相应的方式方法加以回收利用；进一步介绍了几年来济钢烧结厂在这方面所做的工作及取得的成效。     

关于矿山住宅建设现状和未来的探讨

矿山的住宅业不是矿山产业的主体 ,它只是体现其服务矿山职工的物业职能。由于矿产资源的不可再生性 ,决定了矿山服务年限的有限性。因此矿产资源枯竭之日 ,必然导致矿区房产价值的大幅贬值。为降低职工物业投资风险 ,将矿山物业建设纳入周边交通便利、生活服务设施相对齐备的城市之中 ,划区建设不失为一种两全齐美的方案