高深溜井井筒堵塞的爆破处理实践

溜井是采用平硐-溜井方式开拓矿山的运输咽喉,溜井正常与否对矿山生产影响极大。本文通过黑沟铁矿高深溜井井筒堵塞处理实例,对其堵塞爆破处理方法及经验做了系统分析。重点介绍的爆破冲击波破拱疏通高深溜井井筒高位堵塞的爆破方法,富有新意,可供国内外同类型矿山参考借鉴。     

水电站大型竖井施工安全风险控制措施研究

竖井是大型水电工程中广泛采用的重要建筑物,但竖井的传统施工方法存在施工程序复杂、人工劳动强度大、施工效率不高等特点,同时还存在较大的安全风险。通过对杨房沟水电站大型竖井施工过程的研究,总结出精细化控制爆破、小溜渣井施工方式,同时也设计了一套用于运输的综合提升系统。采用上述创新方法不仅减少了繁琐的施工程序,降低了安全施工风险,而且大量采用机械化手段进一步提高了施工效率,确保了该工程竖井施工的安全风险可控。相关措施可为类似工程的竖井施工提供较好的借鉴作用。     

Cutting parameter optimization for one-step shaft excavation technique based on parallel cutting method

The outcome of the cutting blasting in a one-step shaft excavation is heavily related to the cutting parameters used for parallel cutting method. In this study, the relationships between the cutting parameters (such as the hole spacing L and the empty hole diameter D) and damage zones were investigated by numerical simulation. A damage state index γ was introduced and used to characterize the crushing and crack damage zones through a user-defined subroutine. Two indices, i.e., η₁ and η₂ that can reflect the cutting performance, were also introduced. The simulation results indicate that an optimal value of L can be obtained so that the η₁ and η₂ can reach their optimal states for the best cutting performance. A larger D results in better cutting performance when the L value maintains its best. In addition, the influences of the loading rate and the in-situ stress on the cutting performance were investigated. It is found that an explosive with a high loading rate is suit for cutting blasting. The propagation direction and the length of the tensile cracks are affected by the direction and the magnitude of the maximum principal stress.     

基于液固耦合的搅拌轴疲劳强度分析

针对浮选机主轴的疲劳强度问题,基于液-固耦合的方法,采用流体分析与疲劳强度分析相结合的方式对浮选机主轴的疲劳强度进行协同计算。根据疲劳强度理论,通过数值分析确定主轴的疲劳极限应力,得出主轴的应力分布规律,该研究对防止主轴疲劳断裂,优化设计浮选机主轴,具有一定的指导意义。     

负径向电场对带电粒子俘获率影响的数值模拟

本文采用数值方法求解Grad-Shafranov方程反演EAST典型长脉冲放电实验(炮号33068)的平衡位形和磁场分布，进而结合粒子在托卡马克电磁场中的运动方程，模拟氘离子在负径向电场存在时的运动轨迹，并统计不同负径向电场下的氘离子俘获率。结果表明：随负径向电场的增大，氘离子轨迹由扩张通行轨迹向外翻香蕉轨迹再向内翻香蕉轨迹，最后向压缩通行轨迹演变；氘离子俘获率随负径向电场的增大而减小，氘离子初始速度越小，其变化越大。     

The influence of inner material with different average thermal conductivity on the performance of whole insulation system for liquid hydrogen on orbit storage

At present, several composite insulation systems were proposed that can be used for passive insulation systems, including foam-variable density multilayer insulation (VDMLI), aerogel-VDMLI and hollow glass microspheres (HGMs)-VDMLI. The passive insulation systems with different inner material (IM) showed different performances. However, the relationship between the average thermal conductivity of IM and the insulation performance of the whole system has rarely been investigated. It is of great significance for efficient configuration and matching of the passive insulation system. In this paper, a series of average thermal conductivity of IM were assumed to predict the insulation performance of the whole system at 20 K–300 K and high vacuum. In order to further illustrate the relationship between IM and MLI/VDMLI, the foam was replaced by the HGMs as 5 mm a unit forming a series of HGMs-foam-MLI/VDMLI insulation systems. The performance of the systems was investigated. After the foam was completely replaced by the HGMs, the performance of MLI and VDMLI systems was improved 33% and 13%, respectively. Moreover, each mode of heat transfer including solid conduction, radiation, and gas conduction for foam-MLI/VDMLI and HGMs-MLI/VDMLI insulation systems were calculated and analyzed.     

Self-consistent kinetic theory with nonlinear wave-particle resonances

We have developed, based on the oscillating-center transformation, a general theoretical approach for self-consistent plasma dynamics including, explicitly, effects of nonlinear(higherorder) wave-particle resonances. A specific example is then given for low-frequency responses of trapped particles in axisymmetric tokamaks. Possible applications to transport as well as nonlinear wave growth/damping are also briefly discussed.     

Toward the Optimized Spintronic Response of Sn‐Doped IrO2 Thin Films

Amorphous and polycrystalline Sn‐doped IrO₂ thin films, Ir_1‐xSn_xO₂, are grown for the first time. Their electrical response and strength of the spin–orbit coupling are studied in order to better understand and tailor its performance as spin current detector material. These experiments prove that the resistivity of IrO₂ can be tuned over several orders of magnitude by controlling the doping content in both the amorphous and the polycrystalline state. In addition, growing amorphous samples increase the resistivity, thus improving the spin current to charge current conversion. As far as the spin–orbit coupling is concerned, the system not only remains in a strong spin–orbit coupling regime but it seems to undergo a slight enhancement in the amorphous state as well as in the Sn‐doped samples.