Numerical evaluation method of lightning rod protection probability北大核心CSCD

［Objectives］Aiming at the current situation in which it is difficult to efficiently evaluate protection probability through traditional lightning rod evaluation methods, an efficient numerical evaluation algorithm is developed on the basis of an electrogeometric model (EGM) and attractive volume to realize the efficient calculation of lightning protection probability at any point in space.［Methods］This method first determines the attractive volume boundary of the lightning rod and protection object according to the interception process of the upward and downward leaders. The collection surface and exposure arc of the lightning stroke distance are then calculated, enabling the attractive risk and interception effect of the lightning rod to be quantified. Finally, the attraction and interception characteristics of the lightning rod are integrated to establish a numerical evaluation model of protection probability. To verify the accuracy of this method, the general rule of lightning rod protection probability is analyzed and the results compared with the existing analysis method.［Result］The evaluation results of this method show good agreement with those of classical leader progression model (LPM) theory.［Conclusions］ The method proposed herein has a high degree of quantification and can realize the efficient calculation of lightning protection probability at any point in space, which can provide useful references for lightning protection design work. © 2023 Authors. All rights reserved.     

大体积混凝土止浆垫块及拉杆装置在龙溪口航电枢纽中的应用

在船闸工程大体积混凝土施工过程中，常使用高大模板，为保证模板的稳固，增加其安全性，现场施工中往往采用斜拉杆对模板加固，并使用发泡剂或者缠绕胶带等进行止浆，然而这种传统的方法往往存在工序复杂、止浆效果不佳、拆模后混凝土外观质量差等缺点。为解决该问题，采用一种基于大体积混凝土高大模板施工的弹性材质止浆垫块，并辅以端头带螺纹的拉杆装置，可有效防止混凝土浆液渗漏，还可为拉杆预留保护层以防止锈蚀。该止浆垫块在现场施工的应用取得了较好成效，在提升施工质量及效率的同时，较大程度改善了混凝土表面外观，可为类似工程的大体积混凝土施工止浆提供参考。     

棒磨机挥发性气体排污特性分析

基于棒磨机挥发性气体逸出造成操作人员职业健康受损的问题，对棒磨机挥发性气体排污特性进行分析。建立棒磨机排污计算模型，分析流场、空气龄和挥发性气体的分布特征与排污效率。结果表明：缝隙可降低棒磨机氨气的体积分数、提升排污效率，但在压差小于15 Pa时挥发性气体会从缝隙中逸出，需要密切关注压差以保证棒磨机缝隙不发生外逸；在相同工况条件下，优化方案的平均排污效率分别提高约68.7%及71.8%，排污效率显著提升；综合考虑氨气的体积分数、外逸的潜在风险性及排污效率，选取60 Pa压差作为最优方案较为合理。