非对称坡面腔底无阀压电泵

提出了一种新型的非对称坡面腔底无阀压电泵,这种泵巧妙地利用了泵腔内部的空间,将泵腔底部沿吸入口和排出口方向设计成非对称坡面形状,非对称坡面腔底与压电振子之间形成非对称交替排列的一组锥形流道。当泵工作时,使流体产生单向流动,从而可以不再需要传统的锥形流管;建立了这种泵关于平均值的流阻系数与泵流量关系的力学模型,并利用该模型分析了泵的工作原理;最后制作了非对称坡面腔底无阀压电泵,利用试验证明了上述理论的正确性。试验用泵采用的工作电压为220 V,工作频率为50 Hz,压电振子有效直径为30 mm,当非对称坡面的倾角差为70°,工作介质为水时,泵产生了4.67 mm水柱的压差。

Effects of torpedo blasting on rockburst prevention during deep coal seam mining in the Upper Silesian Coal Basin

In the Upper Silesian Coal Basin(USCB),coal seams are exploited under progressively more difficult geological and mining conditions(greater depth,higher horizontal stress,more frequent occurrence of competent rock layers,etc.).Mining depth,dislocations and mining remnants in coal seams are the most important factors responsible for the occurrence of rockburst hazards.Longwall mining next to the mining edges of neighbouring coal seams is particularly disadvantageous.The levels of rockburst hazards are minimised via the use of rockburst prevention methods.One active prevention method is torpedo blasting in roof rocks.Torpedo blastings are performed in order to decrease local stress concentrations in rock masses and to fracture the roof rocks to prevent or minimise the impact of high-energy tremors on excavations.The estimation of the effectiveness of torpedo blasting is particularly important when mining is under difficult geological and mining conditions.Torpedo blasting is the main form of active rockburst prevention in the assigned colliery in the Polish part of the USCB.The effectiveness of blasting can be estimated using the seismic effect method,in which the seismic monitoring data and the mass of explosives are taken into consideration.The seismic effect method was developed in the Czech Republic and is always being used in collieries in the Czech part of the coal basin.Now,this method has been widely adopted for our selected colliery in the Polish part of the coal basin.The effectiveness of torpedo blastings in the faces and galleries of the assigned longwall in coal seam 506 has been estimated.The results show that the effectiveness of torpedo blastings for this longwall was significant in light of the seismic effect method,which corresponds to the in situ observations.The seismic effect method is regularly applied to estimating the blasting effectiveness in the selected colliery.

彩超引导下的粗针穿刺活检术在腮腺肿瘤诊断中的应用

目的:探讨彩超引导下粗针穿刺活检在腮腺肿瘤术前诊断中的应用。方法:回顾2013~2015年于湖北省恩施州中心医院术前行彩超引导下粗针穿刺活检的腮腺肿瘤患者63例,将彩超引导下粗针穿刺活检的结果与术后组织病理学结果进行比较并统计。结果:63例腮腺肿瘤患者中,彩超引导下粗针穿刺活检诊断良性肿瘤56例,其中有1例术后病理检查报道为粘液表皮样癌,彩超引导下粗针穿刺活检诊断符合率98.2%;彩超引导下粗针穿刺活检诊断恶性肿瘤7例,彩超引导下粗针穿刺活检诊断符合率100%。彩超引导下粗针穿刺活检术术后发生并发症11例,术区疼痛6例,术区肿胀5例,无面神经损伤病例。结论:彩超引导下粗针穿刺活检术在腮腺肿瘤诊断中准确率高,术后并发症少,无不可逆性损伤。