300kA新式异型阴极双钢棒铝电解槽生产实践

300kA新式异型阴极双钢棒铝电解槽可有效减缓铝液的流动、大幅降低铝液水平电流、降低铝液和电解质界面变形的波形幅度、提高电解槽的稳定性、降低电解槽的工作极距,同时使槽侧部由原来的散热型改为保温型来维持电解槽的热平衡。在保证电解槽平稳高效生产的前提下,电流效率比普通异型阴极电解槽高1个百分点以上,吨铝直流电耗降低400kWh。     

中铝青海分公司优化扁锭生产工艺降低合金单耗

中铝青海分公司针对铝、钛、硼合金单耗偏高的问题,经长期认真跟踪分析,制定了降低合金单耗的具体措施,使铝、钛、硼合金单耗同比下降0．41kg,／t,吨扁锭成本节约12元。生产过程中,青海分公司铸造厂适量降低铝、钛、硼丝喂丝速度,摸索出扁锭晶粒度和质量稳定的最佳值,降低合金消耗;执行降低喂丝速度设定标准后,还对铝、钛、硼合金采用统一入库管理,     

铝铬渣对锑冶炼炉用铝铬砖性能的影响

在传统锑冶炼炉用铝铬砖中引入不同含量的铝铬渣,设定合理的热处理温度,在保证制品优良性能的基础上逐步降低铝铬砖的成本,提高其性价比,试验结果表明:(1)锑冶炼炉用铝铬砖中可引入适量铝铬渣降低原料成本;(2)铝铬砖中最佳的铝铬渣加入量为30%;(3)加入量30%铝铬渣的铝铬砖较佳烧成温度为1600℃。     

Na3AlF6-K3AlF6-AlF3电解质体系铝溶解度的研究

采用质量差法研究了不通电时Na3AlF6-K3AlF6-AlF3体系中铝的溶解度。实验首先测定了不同时间内铝溶解的情况,并确定铝饱和溶解的时间为3 h。主要研究了初晶温度、过热度、电解质组成,以及电解质融化之后的熔盐深度对铝溶解度的影响。实验选用刚玉坩埚盛装电解质。测试结果表明,初晶温度为670～900℃的电解质,铝的溶解度为0.05%～0.50%(质量分数)。在初晶温度较低的电解质中,铝的溶解度较低,反之较高。对于某个特定体系来说,提高过热度会增加铝的溶解度。电解质的组成对铝溶解度的影响是:增大KR,可以降低铝的溶解度;AlF3含量增加,铝溶解度降低;对于KR=30,AlF3=26%(质量分数)的电解质,出现了异常的情况。另外,减少电解质的用量,降低熔盐的深度,也会造成铝的挥发损失,并最终导致铝的溶解增加。总之,影响铝溶解度的因素是多方面的,抑制铝的溶解损失,可以从改变电解质的组成、降低初晶温度、减少铝的挥发等方面着手。     

虹吸管在铝液转注中的应用

分析铝电解企业普遍使用的小瀑布铝液转注法对铝液烧损的影响,介绍一种可代替小瀑布铝液转注法的新铝液转注法——虹吸管铝液转注法的原理及其在降低铝液烧损中的作用与效果。     

BP神经网络IF钢铝耗的预测模型

为了解决某钢厂IF钢冶炼RH精炼过程铝耗偏高问题,通过数理统计和BP神经网络相结合的方法建立了铝耗预测模型,并与多元线性回归模型进行比较,该模型具有更高准确度.该模型分析了不同冶炼工艺参数对铝耗的具体影响,并对相应工艺参数进行了优化.结果表明:脱碳结束氧活度或RH进站氧活度降低0.005%左右,每吨钢铝耗可降低0.07~0.08 kg,铝脱氧有效利用系数为70.31%~80.35%;RH进站钢液温度增加35~40℃,铝耗降低1 kg左右,铝热反应升温利用系数在97.4%左右;吹氧量小于100 m3和大于100 m3时,氧气与铝反应的比例分别为37.3%和74.6%左右,吹氧量每增加50 m3,铝耗分别增加0.1 kg和0.2 kg左右.工艺参数优化后平均铝耗由1.359 kg降低到1.113 kg,降幅达18.1%.      

114．5kA导流槽铝液流场数值模拟研究

以商用有限元流体计算软件CFX为计算平台,对114．5kA导流型铝电解槽由电磁力引起的对铝液流动和波动的影响进行了模拟计算。结果表明,导流型电解槽铝液平均流速较传统电解槽降低了50％,在铝液填满沟槽的极限情况下,聚铝沟内铝液界面波动的最大隆起值为1．04cm,较传统槽的3．1cm有较大幅度的降低,当铝液低于沟槽2cm的一般情况下,铝液波动0．58cm,这时铝液不会溢出沟槽。     

镁 提 高 钢 水 纯 净 度 的 研 究

 在真空感应炉内分别向42CrMo钢液单独加入铝进行脱氧、铝脱氧后加入钙进行钙处理、铝脱氧后加入镁进行镁处理三种不同的工艺条件,得出镁处理的铝脱氧钢总氧含量略低于钙处理的铝脱氧钢,并且明显低于单独用铝脱氧的钢。用镁处理铝脱氧钢中单位面积上夹杂的个数比钙处理铝脱氧钢降低了将近2/3,比单独用铝脱氧钢中单位面积上夹杂的个数降低了将近4/5。并且用镁处理的铝脱氧钢中绝大多数都是细小、尺寸小于2 μm的镁铝尖晶石类夹杂,它们对钢的性能几乎不会产生影响。     

硅铁合金降铝生产方法及效果

介绍了降低硅铁合金铝含量的生产方法及其脱铝效果。精料人炉，强化管理，精心操作以及合理地采取炉外精炼，可进一步降低硅铁合金铝含量至0．5％或0．1％以下，得到优质硅铁，也可得到铝0．03％以下、其它杂质含量也低的较纯净硅铁。     

铝电解槽节能潜力分析与应用实践

铝电解槽的电能消耗量与平均电压和电流效率两个因素有关,降低槽电压或者提高电流效率,可降低铝电解槽直流电耗。通过系统测试系列电解槽电压平衡、能量平衡、电流效率,深入挖掘分析,提出了节能降耗技术措施。通过2台试验槽工业试验表明,试验槽平均电压3.819 V,电流效率92.89%,吨铝直流电耗12 251 kWh。与系列电解槽相比,平均电压降低99 mV,电流效率提高1个百分点,吨铝直流电耗降低455 kWh,节能效果显著。     

6kV电网接地电流分析及选线装置设计

中铝山西分公司主6kV电网属于小电流接地系统，单系统容量在同类型电网中居全国之首。本文以山西分公司电网为例，对大中型经消弧线圈接地的小电流接地系统进行接地电流分析以及探索相适应的选线方法具有积极的应用意义。     

Estimation of outward currents in isolated human atrial myocytes using inactivation time course analysis

The aim was to investigate outward currents in single, isolated, human, atrial myocytes and to determine the relative contribution of individual current components to the total outward current. Currents were recorded using the whole-cell patch-clamp technique at 36-37 degreesC. Individual outward current components were estimated from recordings of total outward current using a mathematical procedure based on the inactivation time course of the respective currents. This method allows estimation of outward currents without the use of drugs or conditioning voltage-clamp protocols to suppress individual current components. A rapidly activating and partially inactivating total outward current was recorded when myocytes were voltage clamped at potentials positive to -20 mV (peak current density 24. 0+/-0.97 pA/pF at +40 mV; n=107 cells, 33 patients). This total outward current comprised three overlapping currents: a rapidly inactivating, transient, outward current (Ito1) a slowly and partially inactivating current (ultrarapid delayed rectifier, IKur) and a third current component which most probably reflects a non selective cation current (not characterized). The average current densities at +40 mV were 8.92+/-0.44 pA/pF for Ito1 and 15.1+/-0.72 pA/pF for IKur (n=107 cells). Recovery from inactivation was bi-exponential for both currents and was faster for Ito1. A slowly activating delayed rectifier current (IK) was not found. The current densities of peak Ito1 and IKur varied strongly between individual myocytes, even in those from the same patient. The ratio IKur/Ito1 was 0.5-6.9 with a mean of 1.98+/-0.11 (n=107 cells), suggesting that IKur is the main repolarizing current. The amplitudes of the total outward current, Ito1 and IKur, and the ratio of the latter two were independent of patient age (16-87 years).     

High-gain, low-noise amplification in olfactory transduction

It is desirable that sensory systems use high-gain, low-noise amplification to convert weak stimuli into detectable signals. Here it is shown that a pair of receptor currents underlying vertebrate olfactory transduction constitutes such a scheme. The primary receptor current is an influx of Na+ and Ca2+ through cAMP-gated channels in the olfactory cilia. External divalent cations improve the signal-to-noise properties of this current, reducing the mean current and the current variance. As Ca2+ enters the cilium, it gates Cl- channels, activating a secondary depolarizing receptor current. This current amplifies the primary current, but introduces little additional noise. The system of two currents plus divalent cations in the mucus produces a large receptor current with very low noise.     

The American Journal of Ophthalmology 1862-1864

A hyperpolarization-activated current (termed I[h]) is believed to provide a pacemaker depolarization in sinoatrial node cells and in some central and peripheral neurons. In the present study, we examined if such an inward cation current exists in primary auditory neurons using the whole-cell patch-clamp technique. A large inward, non-inactivating current was seen during hyperpolarizing steps negative to the resting potential. A depolarizing sag occurred during hyperpolarizing current injection, and upon termination of the current injection there was an overshoot, or a rebound firing. A low concentration of Cs+, but not Ba2+, reversibly blocked the inward current and depolarizing sag. The activation of the current showed voltage dependence with half-activation occurring at -101 +/- 1 mV. The time course of I(h) activation was fitted by double exponential function and was voltage-dependent (time constants: tau1 and tau2 = 480 and 3125 ms at -100 mV, and 66 and 404 ms at -160 mV). The reversal potential of the current was -36 mV measured from tail currents. The conductance of the current was decreased in Na+-free solution, and increased in high K+ solution. Increases in the levels of intracellular cAMP or cGMP enhanced the current. The results suggest that there exists a hyperpolarization-activated inward cation current in mammalian primary auditory neurons. This current may provide a depolarizing current during the membrane hyperpolarization following each firing of the primary auditory nerve.     

Effects of nitric oxide in cultured prevertebral sympathetic ganglion neurons

The effects of the nitric oxide donor, S-nitrosoacetylpenicillamine (SNAP), were tested on cultured dissociated guinea pig celiac ganglion neurons using whole cell patch-clamp recordings. S-nitrosoacetylpenicillamine induced a concentration- and voltage-dependent inwardly directed shift in holding current (inward current shift) in 89% of neurons. The inward current shift was prevented by pre-treatment with the nitric oxide scavenger reduced hemoglobin and was abolished by intra- or extracellular cesium. The amplitude of the inward current shift was also sensitive to the extracellular potassium concentration. The S-nitrosoacetylpenicillamine-induced inward current shift was mediated by a decrease in calcium-dependent potassium currents (IAHPs); apamin (100 nM), charybdotoxin (10 nM) or tetraethylammonium (5 mM) reduced but did not abolish the amplitude of its inward current shift and a combination of apamin and tetraethylammonium abolished the S-nitrosoacetylpenicillamine-induced inward current response. In the presence of extracellular cobalt, SNAP produced an outward current that was concentration- and voltage-dependent, abolished by reduced hemoglobin and extracellular cesium and reduced by 4-AP (1 mM); in the absence of cobalt, 4-AP increased the SNAP-induced inward current shift. These data indicate that NO exerts dual opposing effects on neuronal potassium conductances, namely an inward current shift mediated through an inhibition of IAHP and induction of an outward current mediated by activation of the potassium delayed rectifier.     

负荷入侵保护在热轧系统中的应用

针对传统整流变过电流保护灵敏度不足的问题,研究分析了热轧系统中“开口Y”型变压器低压侧故障电流的大小和相位,找出了故障电流的基本相量关系.提出采用“负荷入侵”闭锁逻辑的过电流保护方法,解决了实际问题.     

1500V直流供电系统状态在线监控仪

介绍了一种适用于矿山牵引机车直流供电系统监测与控制的装置,它能正确判明供电系统开关跳闸的原因,监测出跳闸时的电流值及电流变化率,显示电流变化曲线,记录跳闸次数和各种参数,并设定电流超限数值,控制直流高速开关跳闸.     

电流强化对铝电解槽电、磁、流场的影响

在一定的技术条件下通过电流强化可以提高电解槽铝产量和电流效率,降低单位产品的成本。本文以国内最具代表性的郑州龙祥铝业有限公司 154kA侧部四点进电铝电解槽为研究对象,具体分析了电流强化对铝电解槽电、磁、流场的影响。结果表明:当槽型结构与母线配置不变时,电流强化不影响铝电解槽铝液电、磁、流场总体分布规律,但改变铝液层电流密度、铝液磁感应强度和铝液流速大小;阴、阳极电流、铝液层电位差、铝液层电流密度均与系列电流强度具有相同的增加率;铝液层磁感应强度随系列电流强度的增加而线性增加;铝液最大流速、铝液平均流速均随系列电流强度的增加而增大。     

现代铜电解精炼的电流分布

如今现代化铜电解精炼厂越来越多地采用高电流密度。随着电流密度的增加,许多电解精炼厂使用的电流密度已接近极限电流密度。平均操作电流密度接近极限电流密度,就必须维持均衡的电流密度。本文探讨了维持均衡电流分布的重要性,并且讨论了在较高的工作强度下获得和维持优质生产的因素、工艺和实践。     

交流电流密度对X65钢在碳酸盐/碳酸氢盐溶液中腐蚀行为的影响

通过极化曲线测试、浸泡实验和表面分析技术研究了不同交流电流密度对X65钢在碳酸盐/碳酸氢盐溶液中腐蚀行为的影响.随交流电流密度的增加,钝化区宽度明显变窄,点蚀击破电位负移,维钝电流密度增大,腐蚀速率增加.在低交流电流密度下（<100 A·m-2）,维钝电流密度、点蚀程度和腐蚀速率均略增加;在高交流电流密度下（≥100 A·m-2）,维钝电流密度、点蚀程度和腐蚀速率均快速增加.