煤炭开采对农田土壤碳储量的影响研究

以徐州九里矿区为研究区,选取典型煤炭开采沉陷盆地,通过设计沉陷盆地土壤有机碳库采样方案、实验室土壤有机碳含量测定、构建沉陷盆地土壤有机碳库储量模型以及煤炭开采沉陷前后沉陷盆地内农田土壤有机碳库储量变化的分析,研究了煤炭开采对农田土壤碳储量的影响。研究发现：在煤炭开采沉陷未扰动状况下,沉陷盆地各坡面区土壤有机碳密度均与对照区土壤的有机碳密度相同,煤炭开采沉陷后沉陷盆地各沉陷坡面区土壤有机碳密度随沉陷深度呈现先减小后增大的变化趋势：煤炭开采沉陷前沉陷盆地所在区域内土壤碳库有机碳储量是560.4 t,开采沉陷扰动后沉陷盆地内土壤碳库有机碳储量为530.9 t,比沉陷扰动前减少了5.3%,由此可知,煤炭开采对农田土壤碳储量影响为失碳（碳源）效应。     

大佛寺矿沉陷区变形预计及危险性分区

以大佛寺煤矿30201工作面为例,首先分析了矿区地形地貌、工程地质条件及开采情况,结合矿区实际调查结果总结出地层岩性、地形坡度、断层构造、降雨作用、人类工程活动等5类矿山开采沉陷影响因子,并对各因子的影响能力进行了定量化分级;然后利用逻辑回归分析软件SPSS对矿区样本数据进行反演,构建了矿山开采沉陷危险性系数计算模型;最后结合Arc GIS软件构建了物元模型,对矿区沉陷区变形进行了预计,在此基础上以5个开采沉陷影响因子为变量,以10 m×10 m正方形网格为最小评价单元,分别得出各影响因子危险性分布情况作为基础图件,结合概率分析法计算出各模型的关联度与重要性程度,将矿区开采沉陷危险区划分为高危区、中危区、低危区和极低区4类。研究表明:大佛寺煤矿30201工作面地表沉陷范围由北部向东南部倾斜,沉陷预计值为300~650 mm,预计误差为1.7%~7.8%,表明该矿区开采沉陷预计及危险性分区结果基本符合矿区地表沉陷变形规律,对于该矿区安全开采及沉陷区治理有一定的参考价值。     

煤炭开采对农田土壤碳储量的影响研究——以典型煤炭开采沉陷盆地为例

以徐州九里矿区为研究区,选取典型煤炭开采沉陷盆地,通过设计沉陷盆地土壤有机碳库采样方案、实验室土壤有机碳含量测定、构建沉陷盆地土壤有机碳库储量模型以及煤炭开采沉陷前后沉陷盆地内农田土壤有机碳库储量变化的分析,研究了煤炭开采对农田土壤碳储量的影响。研究发现:在煤炭开采沉陷未扰动状况下,沉陷盆地各坡面区土壤有机碳密度均与对照区土壤的有机碳密度相同,煤炭开采沉陷后沉陷盆地各沉陷坡面区土壤有机碳密度随沉陷深度呈现先减小后增大的变化趋势:煤炭开采沉陷前沉陷盆地所在区域内土壤碳库有机碳储量是560.4 t,开采沉陷扰动后沉陷盆地内土壤碳库有机碳储量为530.9 t,比沉陷扰动前减少了5.3%,由此可知,煤炭开采对农田土壤碳储量影响为失碳(碳源)效应。     

厚松散层下深部开采地表沉陷的复合介质模型

以龙固矿巨厚松散层下深部开采为研究背景,分析了煤矿深部开采地表沉陷机理,建立下部离散介质-中部弹性薄板-上部松散层随机介质的耦合模型,对地表沉陷规律进行研究。通过分析各层位岩层的移动特征,推导出其弯曲下沉方程,分别求出各分层的下沉值,再通过线性叠加,得出厚松散层下深部开采的地表下沉值。分别把运用该方法得出的预计结果和运用整体模型进行地表沉陷预计的结果与实测结果进行比较,发现此模型对厚松散层下深部开采地表沉陷的预计结果更为准确。     

煤矿开采沉陷预测模型的三维虚拟仿真

煤矿开采沉陷预测受多参数影响下,沉陷预测效果可视性较差,引入三维虚拟仿真技术进行煤矿开采沉陷预测。构建煤矿开采沉陷复杂模型,计算沉降区域的三维关键点坐标,再选取煤矿开采沉陷约束指标,通过模糊权重方法计算沉陷指标权重数值,并判断开采沉陷预测等级,实现了煤矿开采沉陷预测。运用MATLAB仿真软件,模型进行三维模拟应用。仿真实验数据显示：模型对煤矿开采沉陷预测等级误差为0.63%,煤矿开采沉陷预测效果值高于最低限值,充分证实了方法的可行性。     

红旗铁矿改进Knothe时间函数开采沉陷预计模型

针对Knothe时间函数模型对开采沉陷过程的预计结果与沉陷实际发生过程不完全符合的问题,分析了该模型的缺陷,提出了改进的Knothe时间函数开采沉陷预计模型。结合河北省武安市红旗铁矿6300综放工作面地表沉陷实测数据,构建了改进的Knothe时间函数开采沉陷预计模型,并进行了模型精度分析。研究表明:经过累计387 d观测,改进的Knothe时间函数开采沉陷预计模型的预计值与实测值的误差为0.2~73.6 mm,平均误差为35.2 mm,优于BP神经网络模型(误差为8.1~143 mm,平均为49.9 mm)、SVM模型(误差为0.7~105.1 mm,平均为35.8 mm)以及概率积分法模型(误差为18.2~180.5 mm,平均为102.6 mm),对于高精度预计该矿开采沉陷具有一定的作用。     

西部厚黄土层矿区开采沉陷预计模型

将西部黄土覆盖区地表沉陷分解为黄土层荷载作用下的基岩采煤沉陷以及基岩面不均匀沉降导致的黄土层沉陷,建立了黄土覆盖矿区开采沉陷的双层介质模型。利用FLAC3D软件分析了黄土层自重对基岩开采沉陷的荷载效应,确定了黄土层荷载与开采宽度之间的量化关系。利用随机介质理论建立了基岩面下沉预计公式,将基岩面不均匀沉降视为“不等厚开采”,导出地表沉陷的双重概率积分预计模型。实例应用表明,所建立的预计模型考虑了黄土层自重对基岩开采沉陷的荷载作用以及土层与基岩中预计参数的差异,适用于西部厚黄土层矿区的开采沉陷预计。     

模糊数学模型在金属矿山开采沉陷安全评估中的应用

运用模糊数学理论建立了金属矿山开采沉陷危险性综合评估模型, 对金属矿山开采沉陷的影响因子进行了综合评估预测, 以确定金属矿山开采沉陷的危险级别。结合具体金属矿山实例, 对模型进行了应用检验, 结果表明, 模型与实际情况基本一致。     

不规则工作面开采地表沉陷预计研究

为保证煤矿安全开采,结合某矿三采区的实际开采区域,依据概率积分法原理,建立适用于不规则工作面开采沉陷预计模型,开发岩移预计系统,并根据其上覆岩层实际情况,选取预计参数进行沉陷预计。得到在三种不同的开采方法下,先后开采15煤、2煤共计4个开采区域的地表各种变形值和地表各建筑物的损坏等级。结果表明:所建立的开采沉陷预计模型适宜于不规则工作面的预计,预计结果为实际开采方案的确定提供了依据。     

山区地表移动预计修正模型及其参数求取方法

为了克服山区开采地表沉陷预计模型中的滑移影响函数以及求参模型的缺点,建立了山区开采地表移动变形预计修正模型,即新的滑移影响函数仍沿用原有参数A,P,t形式,但各参数的取值和物理意义存在差异。依据修正模型,以实测下沉值、水平移动值分别与模型预计值之差平方和最小为原则构建适应度函数,基于遗传算法原理进一步提出了山区地表沉陷预计模型求参新方法。最后将提出的山区沉陷预计修正模型和求参方法用于山西某矿工作面开采地表移动,取得了良好的工程实践效果。     

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