Field test of high-power microwave-assisted mechanical excavation for deep hard iron ore

Microwave-assisted mechanical excavation has great application prospects in mines and tunnels,but there are few field experiments on microwave-assisted rock breaking.This paper takes the Sishanling iron mine as the research object and adopts the self-developed high-power microwave-induced fracturing test system for hard rock to conduct field experiments of microwave-induced fracturing of iron ore.The heating and reflection evolution characteristics of ore under different microwave parameters(antenna type,power,and working distance)were studied,and the optimal microwave parameters were obtained.Subsequently,the ore was irradiated with the optimal microwave parameters,and the cracking effect of the ore under the action of the high-power open microwave was analyzed.The results show that the reflection coefficient(standing wave ratio)can be rapidly(<5 s)and automatically adjusted below the preset threshold value(1.6)as microwave irradiation is performed.When using a right-angle horn antenna with a working distance of 5 cm,the effect of automatic reflection adjustment reaches the best among other antenna types and working distances.When the working distance is the same,the average temperature of the irradiation surface and the area of the high-temperature area under the action of the two antennas(right-angled and equal-angled horn antenna)are basically the same and decrease with the increase of working distance.The optimal microwave parameters are:a right-angle horn antenna with a working distance of 5 cm.Subsequently,in further experiments,the optimal parameters were used to irradiate for 20 s and 40 s at a microwave power of 60 kW,respectively.The surface damage extended 38 cm×30 cm and 53 cm×30 cm,respectively,and the damage extended to a depth of about 50 cm.The drilling speed was increased by 56.2%and 66.5%,respectively,compared to the case when microwaves were not used.

透明、可拉伸和抗冻的杂化双网络有机水凝胶

柔性电子产品非常需要具有高透明度和出色回弹性的可拉伸离子导体,但传统的离子导电水凝胶易于干燥和冻结.在此,基于独特的物理和共价杂化交联机制,我们提出了一种新的杂化交联策略,用海藻酸钠(SA)和丙烯酰胺(AM)制备可拉伸和透明的水凝胶(SPH),并通过简单的溶剂置换方法将其转化为有机水凝胶.所得SA-PAM-有机水凝胶(SPOH)表现出出色的综合性能,如优异的抗冻性能(−20℃)、高稳定性(>2天)、高透明度、优异的可拉伸性(~1600%)和高离子电导率(17.1 mS cm^(−1)).因此,由SPOH构筑的摩擦纳米发电机(O-TENG)在10 MΩ的负载下显示出262 mW m−2的瞬时峰值功率密度,并且能有效地收集人体运动产生的机械能来驱动电子手表和发光二极管.此外,O-TENG表现出良好的长期稳定性(2周)和温度耐受性(−20℃).另外,该原料可以通过简单的管状模具法制备成柔性有机水凝胶纤维,该纤维具有高透明度,可用于传输激光.该多功能有机水凝胶具有能量收集和激光传输的应用前景,有望用于可穿戴电子和生物医学领域.