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.     

湿法制酸酸浓控制的研究及探讨

采用WSA制酸,设计和实际生产过程中产品硫酸的浓度达不到98%以上,影响产品销售。通过采取措施和对工艺进行调节,降低烟气净化后的烟气温度在30℃以下,控制硅酸钠的添加量和循环酸的排放频率;实现了酸浓的提高。     

工业钼酸锂的制备

介绍了以钼酸钠为原料制备钼酸锂的工艺，确定了酸沉、碱溶等主要工序的工艺参数，制备出符合Q／JDC-301-2003标准的钼酸锂产品。     

钼精矿焙烧烟气制酸工艺探索

将非稳态制酸技术应用到钼精矿焙烧烟气治理工艺中,烟气可实现达标排放,具有较好的经济效益和环保效益。     

影响精萘质量的原因分析

地工业萘分步结晶法制精萘温度区段的划分、降温速率对精萘结晶点的影响和萘中各类杂质对酸洗比色的影响进行了阐述,并列举了国内外几家工厂生产工艺技术经济参数,为精萘质量的提高提供参考。     

含钒液体除硅过程的研究

探讨了除硅过程的机理,研究了除硅剂种类、用量、液体pH值、温度、静置时间对除硅效果的影响.结果表明:在弱碱性条件下,添加除硅剂A对含钒液体除硅过程具有良好的效果,除硅率可达90%以上,且除硅过程不会造成溶液中钒的沉淀损失.     

热镀锌工艺废酸治理方法的探讨

针对热镀锌酸洗工序中的废酸处理方法进行了探讨,介绍了几种废酸再生回收的工艺原理、设备、运行成本及特点。为企业选择废酸处理设备提供了依据,可供热镀锌企业在选择废酸治理方法时参考。     

不同SiO_2源对酸性球团结构和性能的影响

应用微型烧结法 ,通过多种途径改变球团矿的SiO2 含量 ,研究了酸性球团矿显微结构及其性能。结果表明 ,添加化学纯SiO2 使团块中硅酸盐矿物增多 ,气孔率升高 ,还原性变好 ,但对团块的视密度和抗压强度具有双重性 ;配加海南矿使团块中赤铁矿增加 ,硅酸盐液相增加 ,团块抗压强度增加 ,还原性变好 ;配加膨润土使SiO2 含量由4 .98%增加到 7.83 % ,团块的视密度、抗压强度增加 ,孔隙率下降 ,还原性变差 ,进一步增加SiO2 含量导致相反的趋势。     

粗苯精制废酸再生利用的生产实践

以平煤集团天宏焦化公司3万t/年酸洗法粗苯精制废酸再生处理在硫铵工艺中使用的技术研发过程为基础,研究探索焦化苯精制废酸处理的新工艺,在工业试验中,采用泡沫分离、聚合、乳化物破乳化以及气浮主要工艺技术,将废酸处理到酸焦油、COD脱除率达到85％,满足化产回收硫铵工艺的使用,取得了较好的效果。     

碳质金矿的矿物特征和提金工艺

论述了碳质难处理金矿中碳质物的组成和矿物特性,碳质金矿预处理工艺和提金方法,并重点评述了水氯化法预处理和次氯酸盐浸出我国某些碳质金矿的试验研究结果。     

离子交换法综合处理钼酸铵生产废水的研究

采用DK型大孔交换树脂、AH型树脂和普通交换树脂分别对钼酸铵生产过程中的酸洗废水进行去除并回收钼、铜的研究，同时采用氨化沉淀其余重金属，最后将处理后的废水蒸发结晶。考察了影响钼、铜回收效率以及硝酸铵纯度的一些因素。结果显示，废水中钼的去除回收率达86％～92％，硝酸铵纯度达99％以上，其余重金属的去除率高于98％，具有良好的环境效益和经济效益。