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.     

进度控制与质量控制、安全生产在施工中的关系与作用

在工程建设监理中的三大控制(质量、进度和投资控制)是对立和统一的矛盾体。随着近几年来国家对安全生产的重视,在工程建设监理中又增加了对安全生产的控制,这更进一步加剧了三大控制的难度。在工程建设中投资与进度的关系是加快进度往往要增加投资,采取各种赶工措施使工程建设项目及早竣工,尽快发挥工程建设投资的经济效益。而加快进度,会使人、机械超强工作造成工人疲劳,机械维修、材料供应紧张等施工条件的改变,可能会影响到工程质量及安全生产。     

焙烧钼精矿生产质量控制环的建立与应用

阐述了回转窑焙烧钼精矿过程中影响产品质量的各种因素，旨在建立和实施回转窑焙烧钼精矿质量控制环的管理模式，探求解决制约产品质量瓶颈问题的有效途径。     

五蒸发自动控制系统

介绍了五蒸发生产工艺和计算机系统的组成、系统组态和控制组态 ,对回路控制和电机控制作了详细分析 ,并对现场仪表选型作了说明。     

燃油退火炉温度的智能控制

简要介绍智能控制在燃油退火炉温度控制过程中的应用。针对燃油退火炉的特性,智能控制器采用了产生式知识结构表达,将技术人员和操作人员的知识与经验程序化并且传统控制理论方法与智能控制方法相结合。控制系统投入应用后,运行结果表明,系统输出响应快,超调小,控制精度高,适合于实际工业过程控制。     

加强内部会计控制的思考

内部会计控制对于规范会计行为，保证会计信息质量，纠错防弊，保护资产的安全完整具有重要意义。针对目前因内部会计控制存在的控制制度内容不完善、控制体系不完整而出现的会计信息失真、内部管理失控的现象．提出应建立健全授权批准控制、不相容职务分离、预算控制等制度，同时提出了内部控制制度应达到的目标、建立的体系及遵循的原则。     

旋涡柱连续炼铅新工艺配料精确控制系统设计

介绍了铅精矿的精确配料在旋涡柱连续炼铅新工艺及控制系统的配置,阐述了常用的配料控制方案在实际生产中存在的问题,以及如何在实际生产中实现铅精矿的精确配料控制。     

模糊控制在位置自动控制中的应用与研究

位置自动控制在钢铁企业里占有极为重要的地位,它是以传统控制理论为依据,用编码器或直线位移传感器检测出实际位置作为反馈来进行控制。而钢铁企业现场环境又比较恶劣,这些元件在这样的环境下很容易损坏,这就给生产带来很多不便。主要表现在影响生产的顺利进行,增加设备的备件和维修成本,要消耗大量人力去维护、保养和更换。基于这些原因,根据位置自动控制理论,引入了模糊控制,用模糊控制理论取代传统控制理论,用软件代替位置检测装置来实现位置自动控制。通过在现场的实际应用,取得了很好的效果,也获得了很高的经济效益。     

模糊仿人控制器在圆锥破碎机控制中的应用研究

根据模糊控制技术的抗干扰能力和仿人控制的抗时滞能力的特点，提出了模糊控制和仿人控制相结合的算法——模糊仿人控制算法，并把它综合应用于大滞后、强干扰的复杂工业过程中——典型的圆锥机控制系统中。仿真研究表明，该算法是一种非常行之有效的控制方法，具有很强的抗滞后性和抗干扰性，特别适用于大滞后、强干扰的对象。     

建筑工程施工管理应注意的有关事项

本文从施工组织设计、质量控制、进度控制、成本控制几个方面,阐述了工程项目施工管理中应注意的有关事项及解决措施     

一种基于模糊神经网络FNN在加热炉温度控制中的应用

从实际出发,以昆明钢铁集团公司中板厂加热炉为研究对象,对具有时变性、非线性、模糊性的随机过程进行了研究。着重研究了神经网络与模糊系统融合的可行性及融合方式,采用了一种新型的智能控制方案——模糊神经网络控制。对提出的模糊神经网络控制算法进行了仿真试验,仿真结果表明,对比PID控制和自整定PID控制,采用本文所提出的模糊神经网络控制算法对加热炉进行控制,具有推理速度快,跟踪性能好,抗干扰能力强的优点,它完全能够满足工业生产需要,具有较强的可行性和实用性。