江西某铀矿堆浸工艺参数的设定及工艺参数优化

铀矿堆浸浸出法进行铀矿采集生产时存在着矿料浸出率过低、溶解酸耗量过大、产生较大环境污染等问题。以江西某铀矿作为研究对象,通过堆浸试验进行分析研究,优化铀矿堆浸的工艺参数:铀矿堆浸高度宜为3.5~4.0m,矿石粒径级配为6~8mm,在喷淋浸出初期(0~30d)采用20g/L的浓硫酸进行喷淋,喷淋强度宜为15L/(h·m2),在喷淋浸出期(30d~60d)采用20g/L的浓硫酸进行喷淋,喷淋强度宜为20L/(h·m2),在喷淋浸出后期(60d~120d)采用10g/L的浓硫酸进行喷淋,喷淋强度宜为8L/(h·m2)。     

Optimizing dewatering design for a metro station on the Chengdu Metro Line 7

At present, most calculation results regarding foundation pit dewatering are ideal values, making construction resources prone to being wasted. In order to optimize the traditional pipe well design of large wells, the linear programming solution module in Excel is used, with the total water inflow taken as the objective function, the water level drawdown used as the constraint and test condition, and a station project on the Chengdu Metro Line 7 serving as the subject of this study. The total water inflow of the traditional pipe well design is optimized by the simplex method, producing a total water inflow of 4 040.65 m3/d, which, compared with 4 829.79 m3/d, the total water inflow calculated by means of the traditional design optimization method, engenders a reduction of roughly 16% per day. The feasibility of the optimization methodology is verified by the drawdown constraint, which reveals the decrease of construction costs and the diminution of the influence that the lowered groundwater level has on the surroundings of the metro station. Finally, references are provided as to optimizing the dewatering designs for other metro stations in similar engineering and hydrogeological conditions.     

印度洋深海沉积物可培养放线菌分离样品预处理条件的优化

海洋沉积物微生物资源丰富,放线菌是其中的优势类群之一,但是海洋放线菌纯培养难度较大.本文利用响应面法对采自印度洋的深海沉积物样品进行湿热处理条件优化,实验中选取了5个因素设计实验,生长的放线菌经纯化培养后,针对16S rRNA基因进行测序分析,以每种优化条件下培养出的放线菌种类数为响应值,优化结果最终为:湿热处理温度5...     

Analysis of effects of operating parameters on rate of penetration in drilling process with air down-the-hole hammer

Air down-the-hole(DTH)hammer drilling has long been recognized to have the potential of drilling faster than conventional rotary drill,especially in some hard rocks such as granite,sandstone,limestone,dolomite,etc.with the same weight on bit(WOB)and rotations per minute(RPM).So,it has been widely used in many drilling fields including mineral resource exploration drilling,oil and gas drilling and geothermal drilling.In order to reduce drilling cost by selecting optimal drilling parameters,rate of penetration(ROP)should be estimated accurately and the effects of different factors on ROP should be analyzed.In this research,ANN model with several multi-layer perception back propagation(BP)networks for predicting ROP of air DTH hammer drilling was developed using controllable parameters such as impact energy,impact frequency,WOB,RPM and bit operating time for the formations with a certain drillability index of rock.Several BP neural networks with the different neurons in hidden layers were developed and compared for selecting optimal architecture of ANN.The effects of the drilling parameters such as impact energy,impacting frequency,WOB,RPM and bit operating time on the ROP of air DTH hammer drilling were investigated by trained ANN.From the analyses,the optimum range of drilling parameters for providing high ROP were determined and analyzed for a formation with a certain drillability index of rock.The methodology proposed in this study can be used in many mathematical problems for optimization of drilling process with air DTH hammer.     

磁法数据处理中的扩边和优化中值滤波方法的研究

依据地质体在地面上引起磁异常的特点,提出了三方向扩边方法,这种方法能够减小边界效应,使处理结果更可靠。在实际的测量中,磁法数据受外界的干扰比较大,干扰因素给数据处理和资料解释工作带来了影响。首次将中值滤波技术引入到磁法数据处理中,提出了一种新的滤波方法,即优化中值滤波方法,来解决这个问题,并给出了优化中值滤波的模型以及计算公式。最后利用优化中值滤波方法对实际磁测数据进行处理,取得了较好的效果。     

首钢曹妃甸钻孔桩海水泥浆应用研究

在滨海浅滩进行钻孔灌注桩施工时,能否应用海水配制泥浆、应用什么样的造浆材料和处理剂、泥浆指标的合理应用是钻孔灌注桩成功施工的重要因素。通过对几种造浆材料的比选,泥浆配比的优化,对使用海水配制膨润土泥浆的可行性进行了分析。结合首钢曹妃甸2号高炉区钻孔桩施工实例,简要介绍了膨润土海水泥浆的成功应用,对施工过程中的控制方法做了说明,以达到指导类似工程施工的目的。     

基于最优化算法的北京市新一代天气雷达Z-R关系研究

运用最优化方法,选取北京市新一代天气雷达2007年4场降雨的基数据资料与对应的雨量计资料进行Z-R关系研究,对不同类型的降雨和不同距离范围的雷达估测点分别优化.结果表明:运用优化后的Z-R关系估测降水量的误差要比缺省的Z-R关系式直接计算出降水量的误差小得多;层状云降水的估测结果优于对流云降水的估测:距离雷达站较近的地区其估测结果优于较远的地区.     

GPS高程转换的模型参数优选与稳健估计

在进行GPS高程拟合时,如果所用函数模型中未知参数个数不恰当,或者随机模型中采用了一个不合理的权阵,都将导致所建数学模型和客观实际存在较大偏差,而影响最终的拟合精度。文中研究了GPS高程拟合时对所建立的数学模型进行参数优化选择和稳健估计,计算数据表明该方法比常规方法在精度上有所提高。     

Mission design for Human Outer Planet Exploration (HOPE) using a magnetoplasma spacecraft

To send humans beyond Mars, a Human Outer Planet Exploration (HOPE) mission has been studied for new spacecraft concepts and technologies. In this paper, an interplanetary trajectory and a preliminary spacecraft design are presented for the HOPE visit to Callisto, one of Jupiter's moons. To design a round-trip trajectory for the mission, the characteristics of the spacecraft and its trajectories are analyzed. A detailed optimization approach is formulated to utilize a Variable Specific Impulse Magnetoplasma Rocket (VASIMR) engine with capabilities of variable specific impulse, variable engine efficiency, and engine on-off control. It is mainly illustrated that a 30 MW powered spacecraft can make the mission possible in a 5-year round trip constraint around the year 2045. Trajectories with different power and reactor options are also discussed. The results obtained in this study can be used for formulating an overall concept for the mission.     

A continuum mechanics‐based framework for boundary and finite element mesh optimization in two dimensions for application in excavation analysis

The determination of the optimum excavation sequences in mining and civil engineering using numerical stress analysis procedures requires repeated solution of large models. Often such models contain much more complexity and geometric detail than required to arrive at an accurate stress analysis solution, especially considering our limited knowledge of rock mass properties. This paper develops an automated framework for estimating the effects of excavations at a region of interest, and optimizing the geometry used for stress analysis. It eliminates or simplifies the excavations in a model while maintaining the accuracy of analysis results. The framework can equally be applied to two‐dimensional boundary and finite element models. The framework will have the largest impact for non‐linear finite element analysis. It can significantly reduce computational times for such analysis by simplifying models. Error estimators are used in the framework to assess accuracy. The advantages of applying the framework are demonstrated on an excavation‐sequencing scenario. Copyright © 2005 John Wiley & Sons, Ltd.