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爆源和测点深度对水下爆炸冲击波载荷的影响
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作者 郑永辉 魏继锋 胡英娣 《兵器装备工程学报》 CAS CSCD 北大核心 2022年第11期219-224,共6页
采用数值仿真方法,构建有限元仿真模型,研究了爆源与测点深度相同、爆源深度一定和测点深度一定时冲击波载荷的变化规律。结果表明:爆源深度和测点深度对冲击波超压峰值、冲量和能流密度的影响程度并不相同,其中,测点深度对超压峰值的... 采用数值仿真方法,构建有限元仿真模型,研究了爆源与测点深度相同、爆源深度一定和测点深度一定时冲击波载荷的变化规律。结果表明:爆源深度和测点深度对冲击波超压峰值、冲量和能流密度的影响程度并不相同,其中,测点深度对超压峰值的影响大于爆源深度,爆源深度对冲量和能流密度的影响大于测点深度。 展开更多
关键词 水下爆炸 冲击波 爆源深度 测点深度
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塔里木油田超深井压恢曲线异常分析及解决对策
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作者 苟柱银 刘毅石 +3 位作者 田新建 魏民 杨惠娟 汪茁 《油气井测试》 2024年第5期67-72,共6页
针对塔里木油田超深井压力恢复测试,受试井压力计下深限制及井筒内多相流体重力分异、油水界面变动影响,压力恢复曲线经常出现“局部压力下降”、“直线”等异变特征,影响储层渗流能力、污染状况、边界特征分析,难以对储层进行准确描述... 针对塔里木油田超深井压力恢复测试,受试井压力计下深限制及井筒内多相流体重力分异、油水界面变动影响,压力恢复曲线经常出现“局部压力下降”、“直线”等异变特征,影响储层渗流能力、污染状况、边界特征分析,难以对储层进行准确描述。XX1-3井在压力恢复测试中压力恢复曲线出现“直线”异常特征,严重影响了解释精度及对储层的认识;通过分析井筒内油水界面变化对压力恢复曲线形态的影响,计算液面降落速度,合理设计压力计下入深度及关井时间,使测点压力变化与产层中部压力变化趋势相一致,较好地消除了液面移动造成的压力恢复曲线中“直线”段异常特征,从第二次压恢测试曲线中可以看出,压恢有效压力数据时长占比98.53%,提高了试井资料解释精度,加深了对地层压力、渗流能力、污染状况、边界特征等认识。为超深井中含水较高的油井压力恢复测试提供可借鉴方案,为油气藏开发方案的编制提供了可靠的理论依据。 展开更多
关键词 塔里木油田 超深井 压力恢复试井 重力分异 油水界面移动 测点深度 关井时间 解释精度
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Improvement of High-Speed Detection Algorithm for Nonwoven Material Defects Based on Machine Vision
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作者 LI Chengzu WEI Kehan +4 位作者 ZHAO Yingbo TIAN Xuehui QIAN Yang ZHANG Lu WANG Rongwu 《Journal of Donghua University(English Edition)》 CAS 2024年第4期416-427,共12页
Defect detection is vital in the nonwoven material industry,ensuring surface quality before producing finished products.Recently,deep learning and computer vision advancements have revolutionized defect detection,maki... Defect detection is vital in the nonwoven material industry,ensuring surface quality before producing finished products.Recently,deep learning and computer vision advancements have revolutionized defect detection,making it a widely adopted approach in various industrial fields.This paper mainly studied the defect detection method for nonwoven materials based on the improved Nano Det-Plus model.Using the constructed samples of defects in nonwoven materials as the research objects,transfer learning experiments were conducted based on the Nano DetPlus object detection framework.Within this framework,the Backbone,path aggregation feature pyramid network(PAFPN)and Head network models were compared and trained through a process of freezing,with the ultimate aim of bolstering the model's feature extraction abilities and elevating detection accuracy.The half-precision quantization method was used to optimize the model after transfer learning experiments,reducing model weights and computational complexity to improve the detection speed.Performance comparisons were conducted between the improved model and the original Nano Det-Plus model,YOLO,SSD and other common industrial defect detection algorithms,validating that the improved methods based on transfer learning and semi-precision quantization enabled the model to meet the practical requirements of industrial production. 展开更多
关键词 defect detection nonwoven materials deep learning object detection algorithm transfer learning halfprecision quantization
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渤海近海口软黏土液塑限试验研究 被引量:2
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作者 毕庆涛 曹世超 +2 位作者 吴琦 吴家琦 丁柄栋 《人民黄河》 CAS 北大核心 2019年第5期148-151,共4页
液塑限是为细粒土定名分类、评价工程性质的重要参数,通过对渤海近海口沉积的软黏土进行液塑限联合测定试验和颗粒分析试验,研究了该地区细粒土的液塑限影响因素,并提出了一些建议。研究结果显示,土体中胶粒含量影响着土体的塑性指数,... 液塑限是为细粒土定名分类、评价工程性质的重要参数,通过对渤海近海口沉积的软黏土进行液塑限联合测定试验和颗粒分析试验,研究了该地区细粒土的液塑限影响因素,并提出了一些建议。研究结果显示,土体中胶粒含量影响着土体的塑性指数,并且在反映土样可塑性时有一定的界限和范围,渤海近海口软黏土胶粒临界含量为7.5%。对不同规范所取的测点入土深度区间进行试验研究发现,《土工试验规程》与《土工试验方法标准》测得的土体液塑限指标不同,其原因可能是测点入土深度和对应的含水率并非理想的线性关系,建议在进行液塑限联合测定时考虑此因素,从而使结果更加准确。 展开更多
关键词 液塑限联合定法 塑性指数 可塑性 胶粒 入土深度
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Abnormality monitoring model of cracks in concrete dams 被引量:9
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作者 BAO TengFei QIN Dong +1 位作者 ZHOU XiWu WU GuiFen 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第7期1914-1922,共9页
The abnormality monitoring model (AMM) of cracks in concrete dams is established through integrating safety monitoring theories with abnormality diagnosis methods of cracks. In addition, emphasis is placed on the infl... The abnormality monitoring model (AMM) of cracks in concrete dams is established through integrating safety monitoring theories with abnormality diagnosis methods of cracks. In addition, emphasis is placed on the influence of crack depth on crack mouth opening displacement (CMOD). A linear hypothesis is proposed for the propagation process of cracks in concrete based on the fictitious crack model (FCM). Abnormality points are detected through testing methods of dynamical structure mutation and statistical model mutation. The solution of AMM is transformed into a global optimization problem, which is solved by the particle swarm optimization (PSO) method. Therefore, the AMM of cracks in concrete dams is established and solved completely. In the end of the paper, the proposed model is validated by a typical crack at the 105 m elevation of a concrete gravity arch dam. 展开更多
关键词 concrete dam cracks abnormality monitoring model a linear hypothesis abnormality diagnosis particle swarm optimization method
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