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Evaluation of NLLoc positioning method and seismogenic structure analysis of Luanzhou M_(S)4.3 earthquake
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作者 Zhang Yang Wang Xiao-Shan +3 位作者 Chen Ting Lv Guo-Jun Yu Hai-lin Chen Jun-lin 《Applied Geophysics》 2025年第3期729-738,894,895,共12页
NLLoc is a nonlinear search positioning method.In this study,we use simulated arrival time data to quantitatively evaluate the NLLoc method from three aspects:arrival time picking accuracy,station distribution,and vel... NLLoc is a nonlinear search positioning method.In this study,we use simulated arrival time data to quantitatively evaluate the NLLoc method from three aspects:arrival time picking accuracy,station distribution,and velocity model.The results show that the NLLoc method exhibits high positioning accuracy and stability in terms of arrival time picking accuracy and station distribution;however,it is sensitive to the velocity model.The positioning accuracy is higher when the velocity model is smaller than the true velocity.We combined absolute and relative positioning methods.First,we use the NLLoc method for absolute positioning of seismic data and then the double difference positioning method for relative positioning to obtain a more accurate relocation result.Furthermore,we used the combined method to locate the earthquake sequence after collecting dense seismic array data on the Luanzhou M_(S)4.3 earthquake that occurred on April 16,2021,in Hebei Province.By fitting the fault plane with the relocated earthquake sequences,the results show that the strike and dip angles of the seismogenic fault of the Luanzhou M_(S)4.3 earthquake are 208.5°and 85.6°,respectively.This indicates a high-dip angle fault with North-North-East strike and North-West dip directions.Furthermore,we infer that the seismogenic fault of the Luanzhou M_(S)4.3 earthquake is the Lulong fault. 展开更多
关键词 NLLoc method Combined multiple positioning methods Luanzhou M_(s)4.3 earthquake seismogenic structure Lulong fault
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An Automatic Damage Detection Method Based on Adaptive Theory-Assisted Reinforcement Learning
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作者 Chengwen Zhang Qing Chun Yijie Lin 《Engineering》 2025年第7期188-202,共15页
Current damage detection methods based on model updating and sensitivity Jacobian matrixes show a low convergence ratio and computational efficiency for online calculations.The aim of this paper is to construct a real... Current damage detection methods based on model updating and sensitivity Jacobian matrixes show a low convergence ratio and computational efficiency for online calculations.The aim of this paper is to construct a real-time automated damage detection method by developing a theory-assisted adaptive mutiagent twin delayed deep deterministic(TA2-MATD3)policy gradient algorithm.First,the theoretical framework of reinforcement-learning-driven damage detection is established.To address the disadvantages of traditional mutiagent twin delayed deep deterministic(MATD3)method,the theory-assisted mechanism and the adaptive experience playback mechanism are introduced.Moreover,a historical residential house built in 1889 was taken as an example,using its 12-month structural health monitoring data.TA2-MATD3 was compared with existing damage detection methods in terms of the convergence ratio,online computing efficiency,and damage detection accuracy.The results show that the computational efficiency of TA2-MATD3 is approximately 117–160 times that of the traditional methods.The convergence ratio of damage detection on the training set is approximately 97%,and that on the test set is in the range of 86.2%–91.9%.In addition,the main apparent damages found in the field survey were identified by TA2-MATD3.The results indicate that the proposed method can significantly improve the online computing efficiency and damage detection accuracy.This research can provide novel perspectives for the use of reinforcement learning methods to conduct damage detection in online structural health monitoring. 展开更多
关键词 Reinforcement learning Theory-assisted Damage detection Newton’s method Model updating Architectural heritage
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基于改进Otsu算法的轴承图像阈值分割方法
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作者 赵宇航 吴超华 +2 位作者 王鑫 张晟琦 史晓亮 《机电工程》 北大核心 2026年第1期34-44,共11页
针对轴承装配后质检时,工业相机采集到的图像存在混合噪声和背光源过曝,导致图像分割精度不高、影响后续处理的问题,提出了一种基于多特征感知与贝叶斯优化的改进大津算法(Otsu)的轴承图像阈值分割方法。首先,在图像感知层面,读取、计... 针对轴承装配后质检时,工业相机采集到的图像存在混合噪声和背光源过曝,导致图像分割精度不高、影响后续处理的问题,提出了一种基于多特征感知与贝叶斯优化的改进大津算法(Otsu)的轴承图像阈值分割方法。首先,在图像感知层面,读取、计算了图像的灰度值、梯度幅值、局部二值模型并完成了储存,对三特征数据分别进行了归一化处理,加权融合了三特征数据,得到了轴承图像的加权融合图;然后,在计算效率层面,引入了贝叶斯优化与分块动态规划方法,替代了Otsu的穷举法;最后,结合感知方法与加速方法,得到了一种基于多特征感知与贝叶斯优化的改进Otsu算法(MFB-Otsu),并与其他阈值分割算法进行了性能对比实验。研究结果表明:与Otsu算法、自适应分割算法对比,MFB-Otsu算法在保留了轴承图像全局亮度分布的基础上,强化了外轮廓边缘,抑制了边缘噪声,输出图像边缘平滑,背景与前景彻底分离;在实测边缘提取中,边缘信息保留完整,噪点干扰率相较于Otsu降低了55%;在客观图像评价指标方面,该算法的分割准确率、交并比、F1值分别达到0.997、0.989、0.994,优于Otsu算法和自适应分割算法;在计算效率层面,相较于Otsu提高了12.9%。改进Otsu算法在轴承尺寸检测中表现出良好的通用性与稳定性,具有一定的工程应用价值。 展开更多
关键词 轴承装配 图像处理 图像分割 大津算法 多特征感知和贝叶斯优化 Otsu加速方法 三维度特征加权 分块动态优化
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Study on the Effects of Umbilical Acupuncture’s“Wind-Thunder Interaction Method”on Neuro-Vascular Regulatory Peptide Groups in SCH Patients with Liver Stagnation and Spleen Deficiency
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作者 Yongfeng Li Jialin Cheng +2 位作者 Hairong Wang Bihai Zhou Jianguo Mao 《Journal of Clinical and Nursing Research》 2025年第11期249-255,共7页
Objective:To evaluate the therapeutic efficacy of the umbilical acupuncture’s“Wind-Thunder Interaction Method”in treating schizophrenia(SCH)patients with liver stagnation and spleen deficiency.Methods:A total of 12... Objective:To evaluate the therapeutic efficacy of the umbilical acupuncture’s“Wind-Thunder Interaction Method”in treating schizophrenia(SCH)patients with liver stagnation and spleen deficiency.Methods:A total of 120 SCH patients with liver stagnation and spleen deficiency were selected and evenly divided by ball drawing.The umbilical acupuncture group received the“Wind-Thunder Interaction Method”,while the Western medicine group received pure Western medicine treatment.The outcomes were compared in terms of efficacy and other indicators.Results:The umbilical acupuncture group showed a higher total effective rate,a decrease in disease symptom scores,lower scores on the side effect rating scale,improved cognitive function scores,and excellent laboratory indicators,with p<0.05 between the groups.Conclusion:The“Wind-Thunder Interaction Method”of umbilical acupuncture demonstrated a relatively high effectiveness in treating SCH patients with liver stagnation and spleen deficiency,alleviating symptoms,reducing side effects,improving cognitive function,and facilitating the recovery of neuro-vascular regulatory peptide groups. 展开更多
关键词 Umbilical acupuncture’s“Wind-Thunder interaction method sCH Liver stagnation and spleen deficiency Neuro-vascular regulatory peptide groups
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A Self-Sacrifice Template Method to Produce FeS Encapsulated into N,S Co-Doped Carbon for Improved Lithium Storage Performance
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作者 Xu Liu Lan-Yun Yang +7 位作者 Li-Ting Zeng Yun Peng Chen-Xi Xu Lei Li Jia-Le Sun Yang-Yang Chen Liang Chen Zhao-Hui Hou 《Acta Metallurgica Sinica(English Letters)》 2025年第9期1637-1644,共8页
The development of high-performance transition metal sulfide(TMS)/carbon composites to replace conventional graphite anode remains a critical challenge for advancing lithium-ion batteries(LIBs).In this study,a facile ... The development of high-performance transition metal sulfide(TMS)/carbon composites to replace conventional graphite anode remains a critical challenge for advancing lithium-ion batteries(LIBs).In this study,a facile self-sacrifice template method is developed to prepare FeS encapsulated into N,S co-doped carbon(FeS/NSC)composite using melamine-cyanuric acid(MCA)supermolecule as a multifunctional template precursor.The function of MCA supermolecule for material synthesis is explored,revealing its special function as a dispersant,dopant and pore-forming agent.Furthermore,the effect of Fe source dosage on the morphology,structure and composition of the final products is explored.The resultant FeS/NSC-0.1(where 0.1 represents the mass of added Fe source)exhibits the most optimal proportion,characterized by a good dispersion status of FeS within the NSC matrix,effective N,S co-doping and ample porosity.Benefiting from these merits,the FeS/NSC-0.1 anode demonstrates significantly improved cycling stability and rate capability when compared to the counterparts.Undoubtedly,this work offers a universal method to produce advanced transition metal sulfide/carbon composite electrodes for energy storage and conversion systems. 展开更多
关键词 Lithium-ion batteries Lithium storage performance self-sacrifice template method Melamine-cyanuric acid(MCA)supermolecule Fes encapsulated into N s co-doped carbon(Fes/NsC)composite
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带S形阻尼器矩形钢管混凝土柱-钢梁易修复节点弯矩-转角关系模型研究
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作者 李向民 杨瑞丰 +3 位作者 韩重庆 张富文 冷予冰 许清风 《工程力学》 北大核心 2026年第2期146-157,共12页
为预测带S形阻尼器的矩形钢管混凝土柱-钢梁易修复节点的弯矩-转角关系,提出基于初始转动刚度、抗弯承载力和形状系数的三参数幂函数模型。基于组件法推导了节点的初始转动刚度计算公式,基于塑性极限分析法推导了节点的抗弯承载力计算公... 为预测带S形阻尼器的矩形钢管混凝土柱-钢梁易修复节点的弯矩-转角关系,提出基于初始转动刚度、抗弯承载力和形状系数的三参数幂函数模型。基于组件法推导了节点的初始转动刚度计算公式,基于塑性极限分析法推导了节点的抗弯承载力计算公式,提出了S形阻尼器塑性极限状态时的受拉4铰机制和受压3铰机制。通过对节点试验和有限元参数分析结果的回归分析,得到节点抗弯承载力修正系数和形状系数。模拟带S形阻尼器易修复节点的实际应用,对带S形阻尼器易修复节点的钢框架-钢板剪力墙结构试件进行低周反复荷载试验和有限元参数分析,有限元分析模型中的梁、柱连接采用三参数模型。与节点试件的试验、有限元参数分析结果和结构试件的试验、有限元参数分析结果进行的对比表明,三参数模型对带S形阻尼器易修复节点弯矩-转角关系的模拟精度较高。 展开更多
关键词 钢管混凝土结构 弯矩-转角关系 组件法 s形阻尼器 初始转动刚度 抗弯承载力
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关节镜微创手术治疗膝骨性关节病伴Baker’s囊肿的价值 被引量:6
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作者 刘玉杰 薛静 +5 位作者 周密 王志刚 李众利 魏民 蔡谞 朱娟丽 《第三军医大学学报》 CAS CSCD 北大核心 2008年第15期1408-1410,共3页
目的探讨关节镜微创技术对膝骨性关节病伴Baker’s囊肿的治疗价值。方法采用局麻关节镜微创技术治疗膝骨性关节病合并Baker’s囊肿34例。男性14例,女性20例,年龄53~66岁,平均61岁。术前行膝关节MRI检查28例,CT扫描14例,B超12例,B... 目的探讨关节镜微创技术对膝骨性关节病伴Baker’s囊肿的治疗价值。方法采用局麻关节镜微创技术治疗膝骨性关节病合并Baker’s囊肿34例。男性14例,女性20例,年龄53~66岁,平均61岁。术前行膝关节MRI检查28例,CT扫描14例,B超12例,Baker’S囊肿造影5例。影像学检查显示软骨退变26例,半月板损伤11例,囊肿与后关节囊相通28例,不通6例。关节镜下同期行膝关节清理与囊肿摘除术22例,分期囊肿摘除术12例。局麻关节镜下检查、半月板和软骨损伤创面清理,滑膜切削,然后改为俯卧位关节镜下Baker’s囊肿摘除术。将囊壁与周围组织剥离,刨削器吸引下清除囊壁组织,再用等离子刀冷凝止血,创面组织皱缩消融术。结果手术34例,术后获得随访31例,随访时间9~32个月,平均16个月。术后29例膝关节疼痛、肿胀、绞锁症状和Baker’s囊肿解除,下蹲活动和行走功能恢复正常,自觉疗效满意。无血管、神经损伤、伤口感染和下肢血栓形成。术后Baker’s囊肿复发2例为严重骨关节炎患者。结论关节镜下摘除Baker’s囊肿同期或分期膝关节清理术治疗膝骨性关节病伴Baker’s囊肿方法可行,且创伤小,有利于术后功能恢复,疗效满意。 展开更多
关键词 bakers囊肿 骨关节炎 半月板 膝关节 关节镜
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膝关节镜下后内侧双通道微创治疗Baker's囊肿 被引量:7
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作者 张坡 王晓民 +3 位作者 朱闯 戚征世 戈兵 董士奎 《中国骨与关节损伤杂志》 2019年第4期399-400,共2页
目的探讨关节镜下后内侧双通道法切除Baker's囊肿的临床疗效。方法自2015-10—2017-10采用关节镜下后内侧双通道法微创治疗Baker's囊肿32例。根据Rauschning和Lindgren分级方法评定手术效果。结果 32例均获得随访,随访时间平均1... 目的探讨关节镜下后内侧双通道法切除Baker's囊肿的临床疗效。方法自2015-10—2017-10采用关节镜下后内侧双通道法微创治疗Baker's囊肿32例。根据Rauschning和Lindgren分级方法评定手术效果。结果 32例均获得随访,随访时间平均12.2(6~18)个月。手术时间40~60 min,平均约48 min。术后住院3~7 d,平均5 d。术后1个月MRI复查证实囊肿均被彻底清除,术后无感染,无神经血管损伤。至末次随访时,所有患者未见复发,症状消失,膝关节功能均改善。术后采用Rauschning和Lindgren腘窝囊肿分级标准:0级27例,I级5例。结论关节镜下后内侧双通道法微创治疗Baker's囊肿具有创伤小,康复快,关节功能影响小,复发率低,易于基层临床推广。 展开更多
关键词 bakers囊肿 关节镜 后内侧双通道 微创
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高频超声结合宽景成像技术对Baker’s囊肿破裂的诊断 被引量:2
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作者 张卫平 陈莉 《南昌大学学报(医学版)》 CAS 2013年第5期63-64,93,共3页
目的分析Baker’s囊肿破裂的高频超声及宽景成像声像图表现及其诊断价值。方法回顾分析10例Baker’s囊肿破裂的高频超声及宽景成像声像图,并与术后的病理结果进行对照。结果 10例Baker’s囊肿破裂中,8例破入腓肠肌与比目鱼肌之间,2例破... 目的分析Baker’s囊肿破裂的高频超声及宽景成像声像图表现及其诊断价值。方法回顾分析10例Baker’s囊肿破裂的高频超声及宽景成像声像图,并与术后的病理结果进行对照。结果 10例Baker’s囊肿破裂中,8例破入腓肠肌与比目鱼肌之间,2例破入腓肠肌表层、筋膜深方;1例合并小腿筋膜室综合征,3例合并小腿深静脉血栓。均与手术病理结果相符。结论高频超声结合宽景成像技术可对Baker’s囊肿破裂进行明确诊断。 展开更多
关键词 bakers囊肿 破裂 高频超声 宽景成像技术 诊断
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Clinical application and research of Shao's “three-acupoint and five-needling method” 被引量:1
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作者 张奥 严兴科 刘安国 《World Journal of Acupuncture-Moxibustion》 CSCD 2017年第1期74-80,共7页
Professor SHAO Jing-ming has obtained more significant effect during the clinical practice in treatment of wheezing diseases by adopting "three-acupoint and five-needling method" created by himself, and the effect h... Professor SHAO Jing-ming has obtained more significant effect during the clinical practice in treatment of wheezing diseases by adopting "three-acupoint and five-needling method" created by himself, and the effect has been widely recognized by doctors and patients. After decades of development, Shao's "three-acupoint and five-needling method" has become a therapy with complete theoretical system and a large number of clinical research achievements, and its application scope has been expanded. In this paper, the achievements of Shao's "three-acupoint and five-needling method" during clinical studies in the early, middle and current development stages and related problems were reviewed comprehensively. 展开更多
关键词 three-acupoint andmethod wheezing diseases clinicain the same wayfive-needling method shao's needlingobservation different diseases be treated
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基于重排S-method的多分量辐射源信号分析方法 被引量:2
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作者 荣海娜 张葛祥 金炜东 《西南交通大学学报》 EI CSCD 北大核心 2009年第2期195-200,共6页
为实现多分量辐射源信号的有效检测和识别,提出了基于重排S-method(RSM)的多分量辐射源信号分析方法.针对Wigner-Ville分布交叉项严重和计算复杂度高的问题,采用RSM分析密集、交叠的辐射源信号,给出了其算法的硬件实现和计算复杂度分析... 为实现多分量辐射源信号的有效检测和识别,提出了基于重排S-method(RSM)的多分量辐射源信号分析方法.针对Wigner-Ville分布交叉项严重和计算复杂度高的问题,采用RSM分析密集、交叠的辐射源信号,给出了其算法的硬件实现和计算复杂度分析.该方法能处理线性和非线性调频信号,算法简单,易于实现.复杂体制多分量辐射源信号分析的实验结果表明,该方法能有效分析多分量辐射源信号,时频分辨率高,不受交叉项干扰,具有比Wigner-Ville分布和S-method更强的噪声抑制能力. 展开更多
关键词 时频分析 辐射源信号 多分量 重排s-method
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基于S-method的多分量雷达辐射源信号检测 被引量:2
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作者 荣海娜 张葛祥 金炜东 《四川大学学报(工程科学版)》 EI CAS CSCD 北大核心 2009年第1期174-179,共6页
针对传统时频方法在处理多分量雷达辐射源信号时存在交叉项,不能检测各分量信号时域参数,难以适应低信噪比环境的问题,提出一种基于S-method(SM)的多分量雷达辐射源信号检测新方法。该方法首先计算信号的SM时频分布,然后在时频面的基础... 针对传统时频方法在处理多分量雷达辐射源信号时存在交叉项,不能检测各分量信号时域参数,难以适应低信噪比环境的问题,提出一种基于S-method(SM)的多分量雷达辐射源信号检测新方法。该方法首先计算信号的SM时频分布,然后在时频面的基础上检测各信号分量的瞬时频率和脉冲起止时间。实验结果表明,该方法能处理线性及非线性调频信号、时频分辨率高且不受交叉项干扰,时域检测精度大于98.60%,频域检测精度大于99.48%,信噪比降低时仍然保持强检测能力。 展开更多
关键词 辐射源信号 时频分析 多分量 信号检测 s-method
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Comparative Analysis of Improving Effects of 12 Maize Populations with Improved S_1 Selection Method
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作者 孙峰成 冯勇 +6 位作者 付增娟 苏二虎 张来厚 赵瑞霞 刘志雄 石海波 李美娜 《Agricultural Science & Technology》 CAS 2014年第10期1687-1692,1713,共7页
ln this study, 12 maize populations were improved with the improved S1 selection method, aiming to increase the improvement efficiency of maize popula-tions. The results showed that number of rows per spike, number of... ln this study, 12 maize populations were improved with the improved S1 selection method, aiming to increase the improvement efficiency of maize popula-tions. The results showed that number of rows per spike, number of grains per row and 100-grain weight were the three important component traits of maize yield. The highest genetic increment was found in Mengqun 2, fol owed by Mengqun 4, Mengqun 1 and other 7 maize populations. Negative genetic increment was shown in Mengqun 3 and 3 introduced foreign maize populations. Some changes were shown in spikes, plant traits and genetic diversity of maize populations. Based on our results, we concluded that Mengqun 2, Mengqun 4, Zhongzong 7, Mengqun C and Mengqun A could be directly used for the line breeding by selfing for their higher genetic increment of yield and better improvement effects of other agricultural traits. Compared with these 5 populations, the improvement potential of other maize populations was limited for their lower genetic increment. 展开更多
关键词 lmproved s1 selection method Maize population Genetic gain Comparative analysis
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采用Liutex涡识别法的水泵水轮机S区内流特性分析 被引量:2
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作者 肖业祥 肖微 +2 位作者 任绍成 陈柳 刘子实 《水力发电学报》 北大核心 2025年第1期135-142,共8页
为探究水泵水轮机S特性出现的原因,首先将数值预测的特性曲线与模型试验进行了对比分析,然后基于Liutex涡识别法分析了各过流部件在S特性区的流动和涡旋分布情况,探讨了S区相同转速不同流量工况下的内部流动变化规律。分析发现:相同转... 为探究水泵水轮机S特性出现的原因,首先将数值预测的特性曲线与模型试验进行了对比分析,然后基于Liutex涡识别法分析了各过流部件在S特性区的流动和涡旋分布情况,探讨了S区相同转速不同流量工况下的内部流动变化规律。分析发现:相同转速下水轮机工况蜗壳内的流动稳定性较好,几乎没有涡旋出现;导叶和转轮域内流动较为均匀,只在无叶区分布有少量涡旋,水流稳定性较好。制动工况蜗壳内流动开始变得较不稳定,涡旋集中分布在蜗壳出口环面上,容易形成涡团阻碍水流进入固定导叶;在导叶叶栅间存在明显的涡旋和回流现象,导叶和转轮的叶栅堵塞较为严重。反水泵工况在尾水管出口出现螺旋状回流,导致流入转轮的水流发生旋转失速等不稳定现象;水流一部分在活动导叶进水边沿圆周方向高速流动,存在严重的流动分离现象,涡旋分布最密集,由于无叶区内存在压力突变区,导致涡旋几乎占据整个流道。 展开更多
关键词 可逆式水泵水轮机 Liutex涡识别法 s特性区 涡旋特征
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The Comparison and Contrast of Skopostheorie and Baker's Equivalence Translation Approach
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作者 李永秀 《海外英语》 2011年第7X期176-178,共3页
Equivalence can be said to be the central issue in translation although its different approaches have caused heated controversy.However,as early as the 1970s,the Skopostheorie emerged in Germany,and it seemed to chall... Equivalence can be said to be the central issue in translation although its different approaches have caused heated controversy.However,as early as the 1970s,the Skopostheorie emerged in Germany,and it seemed to challenge the equivalence theories.Although Nida and some linguistics raised some negative problems of this theory,it still rapidly became famous around the world,This article will mainly compare and analyse Skopostheorie and Baker's translation equivalence approach.First,it will give a simple overview of these two approaches.Second,it will discuss the relevant strengths and weaknesses of these two approaches in relation to their usage.Finally,it will discuss combining these two approaches in the same translation. 展开更多
关键词 COMPARIsON and CONTRAsT skopostheorie bakers EQUIVALENCE TRANsLATION APPROACH
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基于概率共因失效的连续时间T-S动态故障树分析 被引量:1
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作者 古莹奎 王波 钱志远 《机械设计与制造》 北大核心 2025年第2期109-113,共5页
针对大型复杂系统存在的共因失效问题,为能够更真实反映系统的可靠性状况,提出基于概率共因失效(PCCF)的连续时间T-S动态故障树(DFT)分析方法。采用模块化方法对系统进行可靠性分析,静态故障树部分采用隐式方法,动态故障树部分采用连续... 针对大型复杂系统存在的共因失效问题,为能够更真实反映系统的可靠性状况,提出基于概率共因失效(PCCF)的连续时间T-S动态故障树(DFT)分析方法。采用模块化方法对系统进行可靠性分析,静态故障树部分采用隐式方法,动态故障树部分采用连续时间T-S动态故障树方法。利用隐式方法计算考虑PCCF的子系统故障概率,得出在不同概率共因失效组发生情况下顶事件的可靠性情况。将子系统的顶事件作为系统的底事件,构建考虑PCCF的组合连续时间T-S动态故障树,最后利用连续时间T-S动态故障树算法对整个系统进行可靠性分析。以柴油机润滑系统可靠性分析为例,通过分析考虑PCCF的连续时间T-S动态故障树并与不考虑概率共因失效的方法进行对比,验证提出方法的有效性。 展开更多
关键词 概率共因失效 模块化方法 T-s动态故障树 隐式方法 可靠性分析
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Q-factor estimation in CMP gather and the continuous spectral ratio slope method 被引量:6
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作者 Wu Zong-Wei Wu Yi-Jia +1 位作者 Guo Si Xu Ming-Hua 《Applied Geophysics》 SCIE CSCD 2018年第3期481-490,共10页
The attenuation factor or quality factor(Q-factor or Q) has been used to measure the energy attenuation of seismic waves propagating in underground media. Many methods are used to estimate the Q-factor. We propose a m... The attenuation factor or quality factor(Q-factor or Q) has been used to measure the energy attenuation of seismic waves propagating in underground media. Many methods are used to estimate the Q-factor. We propose a method to calculate the Q-factor based on the prestack Q-factor inversion and the generalized S-transform. The proposed method specifies a standard primary wavelet and calculates the cumulative Q-factors; then, it finds the interlaminar Q-factors using the relation between Q and offset(QVO) and the Dix formula. The proposed method is alternative to methods that calculate interlaminar Q-factors after horizon picking. Because the frequency spectrum of each horizon can be extracted continuously on a 2D time–frequency spectrum, the method is called the continuous spectral ratio slope(CSRS) method. Compared with the other Q-inversion methods, the method offers nearly effortless computations and stability, and has mathematical and physical significance. We use numerical modeling to verify the feasibility of the method and apply it to real data from an oilfield in Ahdeb, Iraq. The results suggest that the resolution and spatial stability of the Q-profile are optimal and contain abundant interlaminar information that is extremely helpful in making lithology and fluid predictions. 展开更多
关键词 Quality FACTOR PREsTACK Q EsTIMATION generalized s transform spectral ratio sLOPE method Q versus offset
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基于S-Method分布的微多普勒特征分析 被引量:3
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作者 魏迅 袁伟明 郭汝江 《电子测量技术》 2017年第1期76-80,共5页
微多普勒特征是雷达目标所具有的独特特征之一,对目标的分类、识别具有特殊的意义。研究高精度时频分析方法在分析目标微动特性中的作用,可以为后续目标识别提供很好的支撑。S-Method分布作为一种新型的时频分析方法,它基于短时傅里叶... 微多普勒特征是雷达目标所具有的独特特征之一,对目标的分类、识别具有特殊的意义。研究高精度时频分析方法在分析目标微动特性中的作用,可以为后续目标识别提供很好的支撑。S-Method分布作为一种新型的时频分析方法,它基于短时傅里叶变换来实现,减少了分析过程中的运算量,同时能较好地解决交叉项问题。首先对弹道导弹弹头的微动模型进行建模,推导得到微动模型的理论微多普勒频率,然后采用S-Method分布对回波信号进行时频分析仿真实验,获得弹头目标章动的高精度的时间-微多普勒频率图。通过比较其在分析过程中的时频分辨率、交叉项,具体阐述S-Method分布在时频分析中的优势。因此可以将S-Method分布应用于雷达目标微多普勒分析中,分析实时变化的微多普勒频率特征。 展开更多
关键词 微动 微多普勒 s-method分布 时频分析
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2021年11月17日江苏大丰海域M_(S)5.0地震震源机制与发震构造
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作者 康清清 于悦颖 +9 位作者 顾勤平 李玲利 刘芳 王维 杨云 王俊菲 许田 周昱辰 孙小航 孙宗强 《地球物理学报》 北大核心 2025年第5期1884-1895,共12页
基于江苏、山东和上海等区域地震台网宽频带波形资料,采用gCAP波形反演法获取了2021年11月17日江苏大丰海域M_(S)5.0地震的震源机制解、震源矩心深度和矩震级.节面Ⅰ走向96°、倾角71°、滑动角17°;节面Ⅱ走向0°、倾... 基于江苏、山东和上海等区域地震台网宽频带波形资料,采用gCAP波形反演法获取了2021年11月17日江苏大丰海域M_(S)5.0地震的震源机制解、震源矩心深度和矩震级.节面Ⅰ走向96°、倾角71°、滑动角17°;节面Ⅱ走向0°、倾角74°、滑动角160°,说明震源机制以走滑为主.P轴仰角2°,方位48°,反映震源区主压应力呈NEE-SWW向水平推挤特征,与华东现代构造应力场方向基本一致,揭示其受区域应力场控制.本次地震矩震级为MW5.1,与面波震级M_(S)5.0、近震震级ML5.2较为一致.震源矩心深度为14.7 km,与重定位后的震源初始破裂深度16.5 km较接近,推测该地震发生在南黄海盆地地壳中部,震源由深至浅破裂,震源破裂尺度约3.5 km.重定位后余震展布呈现共轭型带状分布,优势分布方向为NWW向和NE向,NE向展布方向与震源机制解两节面走向均不匹配,震中附近亦没有已探明并公布的NE向断裂;而NWW向展布与节面Ⅰ走向相匹配,与附近的南部坳陷西侧断裂走向基本一致,结合区域重、磁场异常分布情况,初步判定节面Ⅰ为同震破裂面.我们推测本次地震为南部坳陷西侧断裂在NEESWW向水平主压应力作用下挤压错动所致,呈NE向线性展布的零星余震穿越苏北—滨海断裂并向SW延伸至大丰海岸线附近,不排除其下方存在NE-SW向展布的隐伏断层,主震发震断层的错动诱发了该断层活动. 展开更多
关键词 大丰海域M_(s)5.0地震 gCAP方法 震源机制解 地震重定位 发震构造
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Study on Characteristics of 3-D Translating-Pulsating Source Green Function of Deep-Water Havelock Form and Its Fast Integration Method 被引量:20
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作者 许勇 董文才 《China Ocean Engineering》 SCIE EI 2011年第3期365-380,共16页
The singularities, oscillatory performances and the contributing factors to the 3-'D translating-pulsating source Green function of deep-water Havelock form which consists of a local disturbance part and a far-field ... The singularities, oscillatory performances and the contributing factors to the 3-'D translating-pulsating source Green function of deep-water Havelock form which consists of a local disturbance part and a far-field wave-like part, are analyzed systematically. Relative numerical integral methods about the two parts are presented in this paper. An improved method based on LOBATTO rule is used to eliminate singularities caused respectively by infinite discontinuity and jump discontinuous node from the local disturbance part function, which makes the improvement of calculation efficiency and accuracy possible. And variable substitution is applied to remove the singularity existing at the end of the integral interval of the far-field wave-like part function. Two auxiliary techniques such as valid interval calculation and local refinement of integral steps technique in narrow zones near false singularities are applied so as to avoid unnecessary integration of invalid interval and improve integral accordance. Numerical test results have proved the efficiency and accuracy in these integral methods that thus can be applied to calculate hydrodynamic performance of floating structures moving in waves. 展开更多
关键词 translating-pulsating source Green's function singularity highly oscillatory function integration method
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