The contact characteristics between cycloidal gear teeth and pinwheel teeth significantly impact the operational performance of cycloidal pinwheel mechanisms.Current research methods tend to rely primarily on theoreti...The contact characteristics between cycloidal gear teeth and pinwheel teeth significantly impact the operational performance of cycloidal pinwheel mechanisms.Current research methods tend to rely primarily on theoretical calculations,with limited use of experimental methods for detecting dynamic contact properties.We propose a novel method for testing the dynamic contact characteristics of cycloidal pinwheel mechanisms.By combining Hertzian contact theory and contact strength theory,we establish a force and meshing stiffness model for the cycloidal and pinwheel gears,and determine the maximum contact stress and variations in pinwheel gear force and meshing stiffness.Based on the principle of photoelasticity,we built a testing platform for the cycloidal pinwheel mechanism to assess its contact characteristics.This platform provides the stress distribution of the cycloidal pinwheel mechanism and allows us to deduce key parameters such as the number of meshing teeth and the meshing interval.This study provides an experimental method for investigating the contact characteristics of cycloidal pinwheel mechanisms.展开更多
The identification of rock mass discontinuities is critical for rock mass characterization.While high-resolution digital outcrop models(DOMs)are widely used,current digital methods struggle to generalize across divers...The identification of rock mass discontinuities is critical for rock mass characterization.While high-resolution digital outcrop models(DOMs)are widely used,current digital methods struggle to generalize across diverse geological settings.Large-scale models(LSMs),with vast parameter spaces and extensive training datasets,excel in solving complex visual problems.This study explores the potential of using one such LSM,Segment anything model(SAM),to identify facet-type discontinuities across several outcrops via interactive prompting.The findings demonstrate that SAM effectively segments two-dimensional(2D)discontinuities,with its generalization capability validated on a dataset of 2426 identified discontinuities across 170 outcrops.The model achieves 0.78 mean IoU and 0.86 average precision using 11-point prompts.To extend to three dimensions(3D),a framework integrating SAM with Structure-from-Motion(SfM)was proposed.By utilizing the inherent but often overlooked relationship between image pixels and point clouds in SfM,the identification process was simplified and generalized across photogrammetric devices.Benchmark studies showed that the framework achieved 0.91 average precision,identifying 87 discontinuities in Dataset-3D.The results confirm its high precision and efficiency,making it a valuable tool for data annotation.The proposed method offers a practical solution for geological investigations.展开更多
Wearable pressure sensors having versatile device structures have been extensively investigated to achieve high sensitivity under mechanical stimuli.Here,we introduce piezoelectric pressure sensors based on fabrics wo...Wearable pressure sensors having versatile device structures have been extensively investigated to achieve high sensitivity under mechanical stimuli.Here,we introduce piezoelectric pressure sensors based on fabrics woven using polyvinylidene fluoride(PVDF)weft and polyethylene terephthalate(PET)warp yarns with different weave structures:1/1(plain),2/2,and 3/3 weft rib patterns.The dependence of the pressure-sensing performance on the weave pattern is demonstrated with an actual large-scale fabric up to the~2 m scale.An optimized pressure sensor with a 2/2 weft rib pattern produced a high sensitivity of 83 mV N−1,which was 245%higher than that of the 1/1 pattern.The detection performance of the optimal fabric was extensively evaluated with a variety of ambient input sources,such as pressing,bending,twisting,and crumpling,as well as various human motions.Further,a large allfabric pressure sensor with arrayed touch pixel units demonstrated highly sensitive and stable sensing performance.展开更多
基金Sponsored by Natural Science Foundation of Hebei Province(Grant No.E2019209153)Tangshan Science and Technology Program(Grant No.22130219G).
文摘The contact characteristics between cycloidal gear teeth and pinwheel teeth significantly impact the operational performance of cycloidal pinwheel mechanisms.Current research methods tend to rely primarily on theoretical calculations,with limited use of experimental methods for detecting dynamic contact properties.We propose a novel method for testing the dynamic contact characteristics of cycloidal pinwheel mechanisms.By combining Hertzian contact theory and contact strength theory,we establish a force and meshing stiffness model for the cycloidal and pinwheel gears,and determine the maximum contact stress and variations in pinwheel gear force and meshing stiffness.Based on the principle of photoelasticity,we built a testing platform for the cycloidal pinwheel mechanism to assess its contact characteristics.This platform provides the stress distribution of the cycloidal pinwheel mechanism and allows us to deduce key parameters such as the number of meshing teeth and the meshing interval.This study provides an experimental method for investigating the contact characteristics of cycloidal pinwheel mechanisms.
基金support in dataset preparation.This study was funded by National Natural Science Foundation of China(Nos.42422704 and 52379109)Opening the fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(Chengdu University of Technology)(No.SKLGP2024K028)Science and Technology Research and Design Projects of China State Construction Engineering Corporation Ltd.(No.CSCEC-2024-Q-68).
文摘The identification of rock mass discontinuities is critical for rock mass characterization.While high-resolution digital outcrop models(DOMs)are widely used,current digital methods struggle to generalize across diverse geological settings.Large-scale models(LSMs),with vast parameter spaces and extensive training datasets,excel in solving complex visual problems.This study explores the potential of using one such LSM,Segment anything model(SAM),to identify facet-type discontinuities across several outcrops via interactive prompting.The findings demonstrate that SAM effectively segments two-dimensional(2D)discontinuities,with its generalization capability validated on a dataset of 2426 identified discontinuities across 170 outcrops.The model achieves 0.78 mean IoU and 0.86 average precision using 11-point prompts.To extend to three dimensions(3D),a framework integrating SAM with Structure-from-Motion(SfM)was proposed.By utilizing the inherent but often overlooked relationship between image pixels and point clouds in SfM,the identification process was simplified and generalized across photogrammetric devices.Benchmark studies showed that the framework achieved 0.91 average precision,identifying 87 discontinuities in Dataset-3D.The results confirm its high precision and efficiency,making it a valuable tool for data annotation.The proposed method offers a practical solution for geological investigations.
文摘目的研究辛前甘桔汤对慢性鼻窦炎(CRS)小鼠长链非编码RNA小核仁RNA宿主基因16(lnc RNA SNHG16)、表皮生长因子受体(EGFR)及黏蛋白5AC(MUC5AC)m RNA表达的影响。方法36只C57BL/6小鼠随机分为正常组、模型组、羧甲司坦组及辛前甘桔汤低、中、高剂量组,每组6只。采用金黄色葡萄球菌鼻腔灌注建立小鼠CRS模型。正常组与模型组小鼠灌胃质量分数为0.9%的氯化钠溶液(0.6 g·kg^(-1)·d^(-1)),辛前甘桔汤低、中、高剂量组分别灌胃辛前甘桔汤水煎液(0.3、0.6、1.2 g·kg^(-1)·d^(-1)),羧甲司坦组灌胃羧甲司坦口服液(0.3 m L·kg^(-1)·d^(-1)),连续干预14 d。采用苏木精-伊红(HE)及阿尔新蓝-过碘酸雪夫(AB-PAS)染色法观察小鼠鼻黏膜结构,免疫组织化学法观察小鼠鼻黏膜EGFR、MUC5AC表达并测量光密度值;酶联免疫吸附试验(ELISA)检测样本中白介素-6(IL-6)、白介素-8(IL-8)、基质金属蛋白酶-9(MMP-9)水平。实时荧光定量逆转录聚合酶链式反应(RT-q PCR)检测样本中lnc RNA SNHG16、EGFR、MUC5AC m RNA的表达。结果与正常组比较,模型组鼻黏膜上皮结构紊乱,IL-6、IL-8、MMP-9含量明显升高(P<0.05),lnc RNA SNHG16、EGFR、MUC5AC m RNA表达明显升高(P<0.05)。与模型组比较,辛前甘桔汤各剂量组IL-6水平显著降低(P<0.05),辛前甘桔汤中、高剂量组MMP-9、IL-8水平降低(P<0.05),辛前甘桔汤各剂量组lnc RNA SNHG16、EGFR、MUC5AC m RNA表达显著降低(P<0.05)。与羧甲司坦组比较,辛前甘桔汤高剂量组lnc RNA SNHG16、EGFR m RNA表达降低(P<0.05)。结论辛前甘桔汤能降低lnc RNA SNHG16、EGFR、MUC5AC m RNA表达,降低EGFR、MUC5AC蛋白表达,减少IL-6、IL-8、MMP-9表达,进而改善鼻黏膜病理改变。
基金supported by grants from the National Research Foundation of Korea (NRF-2016M3A7B4910151 and NRF-2021R1A2C2013501).
文摘Wearable pressure sensors having versatile device structures have been extensively investigated to achieve high sensitivity under mechanical stimuli.Here,we introduce piezoelectric pressure sensors based on fabrics woven using polyvinylidene fluoride(PVDF)weft and polyethylene terephthalate(PET)warp yarns with different weave structures:1/1(plain),2/2,and 3/3 weft rib patterns.The dependence of the pressure-sensing performance on the weave pattern is demonstrated with an actual large-scale fabric up to the~2 m scale.An optimized pressure sensor with a 2/2 weft rib pattern produced a high sensitivity of 83 mV N−1,which was 245%higher than that of the 1/1 pattern.The detection performance of the optimal fabric was extensively evaluated with a variety of ambient input sources,such as pressing,bending,twisting,and crumpling,as well as various human motions.Further,a large allfabric pressure sensor with arrayed touch pixel units demonstrated highly sensitive and stable sensing performance.
