基于GA-BP算法的气化配煤灰熔点预测

为了提高气化配煤煤灰流动温度预测的精度和稳定性,提出将遗传算法(GA)与误差反向传播神经网络(BP)相结合的预测方法,采用GA优化BP神经网路的权值和阈值,再用BP算法训练网络,结合仿真实验分析比较了GA-BP网络算法与常规BP神经网络方法的精度和稳定性。结果表明:GA-BP网络改善了BP网络容易陷入局部极小值和收敛速度慢的缺点,经GA优化的BP神经网络预测方法的预测精度高于BP网络算法,将其应用于气化配煤灰熔点预测有效可行。     

基于改进BP神经网络的矿井瓦斯浓度预测算法

针对传统煤矿瓦斯预警的可靠性差和误差大等问题,提出了一种基于改进BP神经网络的矿井瓦斯浓度预测算法。提出的新型算法在传统BP神经网络算法的基础上,将遗传算法与BP神经网络算法有效结合,采用优化连接权方法对BP神经算法进行优化。该方法降低了瓦斯浓度预测模型的迭代次数和绝对误差。     

基于GA-BP混合算法的煤与瓦斯突出强度预测研究

在以往对煤与瓦斯突出预测的研究中,较多地关注突出动力类型的预测,对于突出强度预测很少涉及。基于影响煤与瓦斯突出的各个因素与突出强度之间存在的复杂非线性映射关系,建立了突出强度预测的神经网络模型。根据遗传算法(GA)和BP算法的特点,将二者结合起来,利用遗传算法优化BP网络权重和阈值,形成GA-BP混合算法。该算法提高了网络性能,在煤与瓦斯突出强度预测中取得良好效果。     

基于灰色关联分析-GA-BP模型预测煤层瓦斯含量

为提高煤层瓦斯含量预测的精度和效率,提出用灰色关联分析从影响因素中筛选主要因素,结合运用GA-BP神经网络预测煤层瓦斯含量的方法。通过遗传算法(GA)优化BP神经网络的权值和阈值,解决BP神经网络易过早收敛极小值以及收敛速度慢的问题。用Matlab构建灰色关联分析-GA-BP神经网络、GA-BP神经网络和BP神经网络模型。选取成庄矿3#煤层的含量与影响因素作为实验数据对该模型进行实验分析,比较三个的预测模型的预测结果。实验结果表明:顶板泥岩厚度、煤层厚度、基岩厚度、煤层深度是影响成庄矿3#煤层瓦斯含量的主要因素。灰色关联分析-GA-BP神经网络预测模型平均相对误差为2.77%,比后两种预测模型的预测结果好,能准确预测煤层瓦斯含量。     

PCA和GA-BP神经网络在边坡稳定性预测中的应用

针对现有边坡稳定性预测模型存在的不稳定性和精度不高的问题,采用主成分分析方法 PCA和遗传算法GA对传统BP神经网络模型进行优化。PCA方法将露天矿边坡稳定性的6个评价指标转换为4个主成分,作为BP神经网络的输入变量;遗传算法对神经网络的初始权阈值进行了筛选优化。经优化后的模型既减少了神经网络的输入变量,提高了学习训练效率,又使得传统BP神经网络模型的精度大大提高。最后将PCA-GA-BP模型、GA-BP模型和传统BP模型得到的预测结果进行对比和误差分析。结果表明,基于PCA-GA-BP神经网络模型的预测精度较好,对露天矿边坡稳定性的预测具有一定的参考价值。     

基于遗传神经网络的煤层瓦斯含量预测

将遗传算法和神经网络结合起来,利用遗传算法优化神经网络的连接权值,建立基于GA-BP混合算法的神经网络煤层瓦斯含量的预测模型,实际预测结果表明,该算法具有较高的预测精度和较快的运算速度,能为矿井瓦斯灾害的预测预防提供帮助。     

基于遗传算法—BP神经网络的突出强度预测

煤与瓦斯突出强度的预测对研究煤与瓦斯突出,保证矿井安全正常生产有着重要意义。本文提出采用遗传算法结合BP神经网络的模型来预测突出强度,采用遗传算法对BP神经网络的权重和阈值进行优化,将优化好的权重与阈值作用于网络进行训练,直至性能函数符合要求。实际计算表明,该模型有较好的预测精度,且克服了普通BP神经网络训练时间长、收敛速度慢的缺点,在已知瓦斯膨胀能和煤层厚度的前提下,可以用该模型对突出强度进行预测。     

基于信息融合和GA-BP的煤矿瓦斯浓度预测方法研究

瓦斯浓度是煤矿安全生产的重要指标,采用合理的模型预测瓦斯浓度可提前采取安全保障措施。将CO浓度、温度、风速和甲烷浓度作为监测数据,设计传感器布局方案,以GA算法优化BP神经网络模型的权值和阈值,提高瓦斯浓度预测模型的准确率。以采样数据的后10组为测试数据,试验结果显示,GA-BP神经网络的预测误差低于5%,可满足使用需求。     

基于GA-BP神经网络的淋水井筒风温预测模型

矿井进风井筒井底风温是井下风流热计算的重要节点。为准确预测淋水井筒风温，利用皮尔逊相关系数分析与遗传算法（GA）优化BP神经网络相结合的预测模型。借助皮尔逊相关系数分析筛选其中3个主要特征变量作为BP神经网络的输入变量，利用GA优化BP神经网络的权值和阈值，并与标准BP神经网络预测模型进行比较。研究结果表明，全部特征变量与特征变量筛选输入的标准BP神经网络预测模型的预测结果的平均绝对百分比误差分别为1.25%和2.33%,GA优化BP神经网络预测模型的预测结果的平均绝对百分比误差分别为0.97%和2.21%,GA-BP神经网络预测模型预测精度高于标准BP神经网络预测模型，基于特征变量筛选的预测模型既保持了较高的预测精度，又提高了预测效率。     

基于小波分析及BP神经网络的瓦斯浓度预测方法研究

提出了一种基于小波分析与BP神经网络的矿井工作面瓦斯浓度预测算法,综合利用了小波分析算法的信号去噪作用以及BP神经网络可以拟合任何非线性系统的能力,并采用Matlab软件实现了该算法在瓦斯浓度预测上的应用。试验结果证明,对于短期内的工作面瓦斯浓度预测,该算法具有较好的预测效果。     

Current situation and future trend of China rare earth luminescent material industry

<正>Rare earth luminescent material is one of the most important application sectors of rare earths.China enjoys the exceptional advantage to develop rare earth luminescent material for its abundant rare earth resources.After several decades'endeavor,China's rare earth luminescent material industry,headed by rare earth phosphor for lamp and LED and high efficient rare earth energy-saving light source,has been gradually developed into a scale industry.China has become a major production base of rare earth phosphor for lamps and rare earth     

China rare earth market review

正June 1~10,2014Rare earth market remained weak.Quoted price of rare earth products was similar to that in May.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,polishing powder and ceramic industries remained inactive.Demand from downstream industry was soft.Consumers purchased on their needs.Suppliers had strong intention to sell.Prices of rare earth products     

Annual Report analysis of Chinese rare earth-related listed companies in 2013

<正>Chinese rare earth-related listed companies have published their 2013 annual reports.It can be understood from their reports that production and operation activities of Chinese rare earth-related companies were still heavily affected by macro economy and industrial policies.They basically followed the steps of national economy.In 2013,world economy recovered slowly but the economy     

Market opportunities and challenges for rare earth polishing powder

正1.Status of rare earth polishing powder Rare earth polishing powder with high content of cerium oxide began to replace iron oxide for glass polishing and became one of the key materials in glass polishing process since 1940.Compared with traditional iron oxide,rare earth polishing powder has many advantages,such as fast polishing rate,high polishing quality and long service life.It can achieve good surface quality and improve operation conditions.For example,in lens polishing,the polishing work that cerium     

Baotou Research Institute of Rare Earths developed a new RE alloy preparation technology

正Pyrometallurgy Laboratory of Baotou Research Institute of Rare Earths had independently developed a new preparation technology of rare earth alloy for NdFeB.The alloy can remarkably enhance the coercivity of NdFeB magnet but also evidently reduce the production cost of the magnet.The new master alloy was prepared in the kA pilot-scale electrolytic cell by the independent technology.The rare earth master alloy can be used as the raw material for NdFeB.Compared     

Market and recycling of NiMH battery

<正>Market status and future trend of NiMH battery1.Global market of small NiMH battery Global market size of small NiMH batteries declined year on year since 2011.The trend will continue to 2018,at the rate of 5%to 10%annually.Demand for small NiMH batteries will be stable gradually.Many electrical apparatuses are powered by the built-in lithium battery today,which is the main reason for the shrunk market of small NiMH batteries.But,for some products,small NiMH     

China rare earth market review

正September 1-10,2014 Affected by the National Day holiday,rare earth transaction was stagnant and the market showed a weak steady state.As there was no good news for downstream market,some products with flat demand would likely rally slightly for some time to     

2014 second batch of rare earth quota released

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矿用防爆轴流对旋主要通风机叶片ANSYS模态分析及应用

高效节能矿用防爆对旋主要通风机的叶片是主要通风机运行的关键部件,叶片在运行时不断受到气流的作用力,从而使叶片产生振动,当叶片振动的频率与叶片的固有频率接近时,容易产生共振从而导致叶片的断裂。一旦叶片断裂时,对主要通风机的安全运行产生致命的影响,从而导致矿山、化工等企业发生重大事故,将会产生不可估量的损失。基于有限元分析软件ANSYS,对高效节能矿用防爆轴流对旋主要通风机叶片进行模态分析及产生对应的六阶模态频率,对主要通风机叶片的运行频率、固有频率及产生的共振问题进行了原理分析,并且解决了叶片频率共振的问题,从而为主要通风机叶片结构设计提供理论依据,并对主要通风机叶片的安全运行提供保障。     

2013 NdFeB export analysis

<正>China totally exported nearly 24,000 tonsof NdFeB products during 201 3,including 18,825 tons of permanent magnet,valued USD 1.34 billion at an average price of 71.4 USD/kg;3,277 tons of NdFeB magnetic powder,valued USD 1 01 million at an average price of 30.9 USD/kg;1,334 tons of strip casting ribbon,with total export value of USD 74million at an average price of 55.3 USD/kg;and 586