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消除脑干听觉诱发电位中刺激伪迹的新方法
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作者 姜言冰 王攀科 林林 《科学技术与工程》 北大核心 2025年第14期5788-5794,共7页
脑干听觉诱发电位(auditory brainstem response,ABR)检测是一种客观检测听力损失的方法,目前在临床上广泛应用,其波形特性会受刺激声参数的影响。采用单极性的刺激声测量的ABR中会存在刺激伪迹,而交替极性是目前消除刺激伪迹的唯一办... 脑干听觉诱发电位(auditory brainstem response,ABR)检测是一种客观检测听力损失的方法,目前在临床上广泛应用,其波形特性会受刺激声参数的影响。采用单极性的刺激声测量的ABR中会存在刺激伪迹,而交替极性是目前消除刺激伪迹的唯一办法。然而,考虑到不同极性的刺激对听觉系统作用的生理差异,交替极性的刺激可能导致诱发的ABR出现潜伏期抖动现象。因此,提出了一种新的消除刺激伪迹的方法——分和极性法,即先分开使用正极性和负极性的刺激再叠加诱发得到的两种响应。实验招募了听力正常的受试者,比较了短声在单极性(正/负极性)、交替极性和分和极性4种极性处理方法下诱发的ABR,以及5种频率的短纯音在交替极性和分和极性两种方法下的ABR,重点关注了它们的波形分化和潜伏期差异。实验结果表明短声ABR在不同极性处理方法下的差异不明显,说明其对刺激极性不敏感;低频短纯音ABR在分和极性下的波形形态比交替极性下的更好,说明低频短纯音ABR对刺激极性较为敏感,且这种敏感程度随着刺激频率的升高而降低。基于对实验结果的分析,对于短声ABR,推荐使用单极性刺激;对于短纯音ABR,推荐使用分和极性法。本文研究检验了分和极性法的可行性,为测量诱发电位时消除刺激伪迹提供了一种新的方法。 展开更多
关键词 脑干听觉诱发电位 刺激伪迹 交替极性 分和极性 短声 短纯音
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Three-dimensional stability of two-step slope with crack considering temperature effect on unsaturated soil
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作者 SHAN Jun-tao WU Yi-min YANG Xiao-li 《Journal of Central South University》 2025年第3期1060-1079,共20页
In existing studies, most slope stability analyses concentrate on conditions with constant temperature, assuming the slope is intact, and employ the Mohr-Coulomb (M-C) failure criterion for saturated soil to character... In existing studies, most slope stability analyses concentrate on conditions with constant temperature, assuming the slope is intact, and employ the Mohr-Coulomb (M-C) failure criterion for saturated soil to characterize the strength of the backfill. However, the actual working temperature of slopes varies, and natural phenomena such as rainfall and groundwater infiltration commonly result in unsaturated soil conditions, with cracks typically present in cohesive slopes. This study introduces a novel approach for assessing the stability of unsaturated soil stepped slopes under varying temperatures, incorporating the effects of open and vertical cracks. Utilizing the kinematic approach and gravity increase method, we developed a three-dimensional (3D) rotational wedge failure mechanism to simulate slope collapse, enhancing the traditional two-dimensional analyses. We integrated temperature-dependent functions and nonlinear shear strength equations to evaluate the impact of temperature on four typical unsaturated soil types. A particle swarm optimization algorithm was employed to calculate the safety factor, ensuring our method’s accuracy by comparing it with existing studies. The results indicate that considering 3D effects yields a higher safety factor, while cracks reduce slope stability. Each unsaturated soil exhibits a distinctive temperature response curve, highlighting the importance of understanding soil types in the design phase. 展开更多
关键词 3D two-step slope cracks temperature effects UNSATURATION limit analysis
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