| 1 | Unsymmetrical load effect of geologically inclined bedding strata on tunnels of passenger dedicated lines显示文摘In order to study the unsymmetrical load effect in geological bedding strata for the Muzhailing tunnel on the Lanzhou-Chongqing passenger dedicated line in China,we investigated the deformation,mechanical response and pressure of the surrounding rock and the mechanical characteristics of bolts of the tunnel.The results suggest that open zones appear at arch and invert where joints open up,when layered stratum is horizontal,or when the dip angle of inclined bedding is small.Open zones occur perpendicular to a joint.The failure mode is bending disjunction at the arch.What's more,with the dip angle increasing,tunnel excavating would induce shear zones where joints experience a certain shear displacement,and lead to obvious geological bedding unsymmetrical load.The failure mode is shear damage.For the joint dip angle in the range of 75-90°,the failure mode is flexural crushing at the wall and vertical shear rupture above the arch.The restraining effect of two sides weakens for vertical dip.On the whole,shear failure instability trend would occur and the tunnel collapses evenly.When the angle between the bolt and structure plane is greater than 23°,bolts can enhance the shearing stiffness of joint plane.Unfortunately,in the general purpose graph of tunnel for 250 km/h of passenger dedicated lines,the bolts have equal length and spacing.The rationale behind this is worthy of further study.For inclined bedding,the surrounding rock pressure at the left wall is more than that at the right wall.In addition,lining is likely to be damaged at left shoulder and side wall.With the dip angle increasing,the unsymmetrical load gradually achieves symmetry.Asymmetry design for support is recommended to reduce the unsymmetrical load on lining disturbed by excavation. | Benguo HE Zhiqiang ZHANG Yu CHEN | 2012 | Journal of Modern Transportation2012，20，1： | 6 |
| 2 | Recognition System for Diagnosing Pneumonia and Bronchitis Using Children’s Breathing Sounds Based on Transfer Learning显示文摘Respiratory infections in children increase the risk of fatal lung disease,making effective identification and analysis of breath sounds essential.However,most studies have focused on adults ignoring pediatric patients whose lungs are more vulnerable due to an imperfect immune system,and the scarcity of medical data has limited the development of deep learning methods toward reliability and high classification accuracy.In this work,we collected three types of breath sounds from children with normal(120 recordings),bronchitis(120 recordings),and pneumonia(120 recordings)at the posterior chest position using an off-the-shelf 3M electronic stethoscope.Three features were extracted from the wavelet denoised signal:spectrogram,mel-frequency cepstral coefficients(MFCCs),and Delta MFCCs.The recog-nition model is based on transfer learning techniques and combines fine-tuned MobileNetV2 and modified ResNet50 to classify breath sounds,along with software for displaying analysis results.Extensive experiments on a real dataset demonstrate the effectiveness and superior performance of the proposed model,with average accuracy,precision,recall,specificity and F1 scores of 97.96%,97.83%,97.89%,98.89%and 0.98,respectively,achieving superior performance with a small dataset.The proposed detection system,with a high-performance model and software,can help parents perform lung screening at home and also has the potential for a vast screening of children for lung disease. | Jianying Shi Shengchao Chen Benguo Yu Yi Ren Guanjun Wang Chenyang Xue | 2023 | Intelligent Automation & Soft Computing2023，37，9： | 0 |
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