一种新型地雷战斗部的数值模拟研究

针对地雷的毁伤目标和特性,提出一种新颖的多棱柱状药型罩结构,其可看作由八个楔形罩对称排列相邻连接而成。应用非线性有限元软件完成了爆炸载荷下多棱柱状药型罩形成射流过程的数值模拟,结果表明新型药型罩结构能够实现预期设想,形成一股汇聚射流。研究结果为地雷战斗部研究提供了一种新的选择。     

Development of titanium bipolar plates fabricated by additive manufacturing for PEM fuel cells in electric vehicles

Bipolar plates (BPs) are one of the main parts of proton exchange membrane (PEM) fuel cell stacks, which constitute a significant percentage of a PEM fuel cell system in terms of cost, weight, and structural strength. Although frequently used graphite BPs have low density, high conductivity, and high corrosion resistance, machining the desired flow channels on these plates is challenging. On the other hand, BPs made of various materials rather than graphite can be also fabricated by additive manufacturing methods. These methods can be considered as a reasonable alternative to conventional machining for the fabrication of graphite BPs in PEM fuel cells regarding material cost, fabrication of flow channels, and some post-processes in which the large-scale manufacturing of graphite BPs is more complex. This study offers a comparison of formed stainless-steel, additive manufactured titanium and machined composite graphite plates having the same flow-field geometry as a bipolar plate. In addition, titanium BPs are coated with gold and their performances are compared. Among the cells tested, the highest peak power of 639 mWcm^?2 is measured from the cell with 450 nm gold coated titanium BP, whereas those of the cell with conventional graphite and stainless-steel BP are only around 322 mWcm^?2 and 173 mWcm^?2, respectively. Moreover, a new titanium bipolar plate design providing high specific power density is also presented.     

Machine learning algorithm selection for windage alteration fault diagnosis of mine ventilation system

Machine learning algorithms have been widely used in mine fault diagnosis. The correct selection of the suitable algorithms is the key factor that affects the fault diagnosis. However, the impact of machine learning algorithms on the prediction performance of mine fault diagnosis models has not been fully evaluated. In this study, the windage alteration faults (WAFs) diagnosis models, which are based on K-nearest neighbor algorithm (KNN), multi-layer perceptron (MLP), support vector machine (SVM), and decision tree (DT), are constructed. Furthermore, the applicability of these four algorithms in the WAFs diagnosis is explored by a T-type ventilation network simulation experiment and the field empirical application research of Jinchuan No. 2 mine. The accuracy of the fault location diagnosis for the four models in both networks was 100%. In the simulation experiment, the mean absolute percentage error (MAPE) between the predicted values and the real values of the fault volume of the four models was 0.59%, 97.26%, 123.61%, and 8.78%, respectively. The MAPE for the field empirical application was 3.94%, 52.40%, 25.25%, and 7.15%, respectively. The results of the comprehensive evaluation of the fault location and fault volume diagnosis tests showed that the KNN model is the most suitable algorithm for the WAFs diagnosis, whereas the prediction performance of the DT model was the second-best. This study realizes the intelligent diagnosis of WAFs, and provides technical support for the realization of intelligent ventilation.     

某金矿尾矿提纯石英应用对比试验研究

针对某金矿，在回收金银的基础上，对金银浮选尾矿进行云母和长石浮选，以及提纯石英试验，最终获得SiO2品位99.91%的石英产品。提纯石英产品与比利时矽比科矿业有限公司石英产品进行对比试验，通过化学成分、粒度组成、熔制、粘度和热膨胀系数测试对比试验，得出金矿提纯石英达到甚至超过矽比科进口石英产品的各项技术指标。     

A mathematical model for open pit mine production scheduling with Grade Engineering® and stockpiling

This paper presents the development and implementation of an innovative mixed integer programming based mathematical model for an open pit mining operation with Grade Engineering framework. Grade Engineering comprises a range of coarse-separation based pre-processing techniques that separate the desirable (i.e. high-grade) and undesirable (i.e. low-grade or uneconomic) materials and ensure the delivery of only selected quantity of high quality (or high-grade) material to energy, water, and cost-intensive processing plant. The model maximizes the net present value under a range of operational and processing constraints. Given that the proposed model is computationally complex, the authors employ a data pre-processing procedure and then evaluate the performance of the model at several practical instances using computation time, optimality gap, and the net present value as valid measures. In addition, a comparison of the proposed and traditional (without Grade Engineering) models reflects that the proposed model outperforms the traditional formulation.     

Evaluation of the environmental impact assessment (EIA) of Chinese EIA in Myanmar: Myitsone Dam,the Lappadaung Copper Mine and the Sino-Myanmar oil and gas pipelines

The economic relationship between China and Myanmar is regarded as a win–win cooperation. However, Chinese investments, especially in extractive and natural resource sectors, are associated with a number of unwanted environmental consequences. Moreover, the environmental impact assessment (EIA) quality of Chinese enterprises has often been criticized. EIA identifies adverse impacts to the environment through evidence-based decision making. On this basis, this paper provides an evaluation of Chinese EIA performance within the natural resources sector through a structured review of 15 environmental impact statements (EISs). This research also evaluates the EISs of the three largest and most controversial projects, the Myitsone Hydropower Dam, Lappadaung Copper Mine and Sino-Myanmar oil and gas pipelines. The findings reveal several omissions, inadequacies and deficiencies in all the projects with a significant number of EISs falling short of satisfactory quality. Through the analysis, the paper summarizes the factors affecting the EIA performance and proposes feasible recommendations to improve EIA practices in Chinese development projects in Myanmar.     

赵庄井田煤层气成藏条件研究

煤层气成藏条件研究是有效划分成藏类型或含气系统，煤层气富集高渗有利区预测、评价及优选的关键基础工作。基于赵庄井田煤层气地质条件及相关测试资料，借鉴前人研究成果，从煤生烃、煤层气储集和煤层气封盖保存条件等方面对赵庄井田煤层气成藏条件进行了研究。研究结果表明:煤中丰富的生烃物质在良好的生烃动力作用下，提高了生烃率和生烃量，为煤层气成藏提供了基础条件；煤变质程度高，促使煤中微小孔隙发育，煤层气储集能力增强和储集空间增大，有利于煤层气大量储存和富集；煤层埋深、围岩特性、构造及地下水径流等地质条件的有机匹配，为煤层气成藏提供了良好的封盖保存条件，是煤层气成藏的关键因素。     

天荣矿二2煤储层物性及特征

煤储层物性及特征是煤层气地质理论的重要内容，加强其研究对提高煤层气勘探开发成效至关重要。基于天荣矿地质、煤层气勘探及相关测试等资料，采用地质与煤层气地质理论对该矿二₂煤储层物性及特征进行了研究。结果表明:天荣矿二₂煤层物理性质良好，生烃物质丰富；煤层含煤性、稳定性、可采性好，煤层气含量和纯度高，可为煤层气开发提供良好对象和气源条件；煤变质程度高，煤中裂隙相对发育，但其渗透性整体较差，渗透率分异显著且普遍低下；煤储层能量较强且分异显著，煤储层压力状态为欠压—超压型，并以正常—超压煤储层压力状态为主，有利于煤层气高产富集。     

沁水盆地赵庄矿3号煤层地面煤层气抽采低产原因分析

在对沁水盆地赵庄矿煤层气开发地质、煤层气生产井资料深入研究的基础上，分析、总结了区内煤层气直井低产原因，并据此提出了区内地面抽采后续开发方向。研究认为:3号煤层气含量偏低、含气饱和度低、临储比低，致使排采阶段气含量可降幅度低，是其低产的宏观表征；3号煤储层不匹配孔级，较差连通性，即微、小孔为主，中孔次之，大孔不发育，微裂隙连通性差，致使扩散缓慢、影响储层改造和抽采效果，是其低产的微观表征；3号煤层远高于顶底板塑性及相近的水平应力，进一步造成改造缝长受限，泄流面积不足。因此，建议区内后续地面抽采方式应以增大泄流面积开发方式为主。     

SAM智能综采技术在龙滩煤矿的应用

介绍了四川省首个智能综采设备在龙滩煤矿3124S工作面的应用情况,总结了SAM智能化综采的六大核心技术,包括成套设备一键启停、液压支架自动跟机、采煤机记忆割煤、机巷远程集中控制、工作环境智能监控、工况监测及故障诊断。通过现场应用,一键启停功能成功率超过90%、自动跟机率平均88%、记忆割煤使用率62%,实现了工作面设备集中控制、回采参数实时监控及故障诊断。结果表明,相较于传统综采工作面,智能化综采工作面生产人员减少50%,工效提高63%,单产提高65%。