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Aftershock sequence simulations using synthetic earthquakes and rate-state seismicity formulation

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Earthquake Science 2014年第4期27卷 401-410页

作者： heming xu Yifeng Cui James H.Dieterich Keith Richards-Dinger Efecan Poyraz Dong Ju Choi San Diego Supercomputer Center University of California Department of Earth Sciences University of California

We use an efficient earthquake simulator that incorporates rate-state constitutive properties and uses boundary element method to discretize the fault surfaces, to generate the synthetic earthquakes in the fault system. Rate-and-state seismicity equation is subsequently employed to calculate the seismicity rate in a region of interest using the Coulomb stress transfer from the main shocks in the fault system. The Coulomb stress transfer is obtained by resolving the induced stresses due to the fault patch slips onto the optimal-oriented fault planes. The example results show that immediately after a main shock the aftershocks are concentrated in the vicinity of the rupture area due to positive stress transfers and then dis- perse away into the surrounding region toward the back- ground rate distribution. The number of aftershocks near the rupture region is found to decay with time as Omori aftershock decay law predicts. The example results dem- onstrate that the rate-and-state fault system earthquakesimulator and the seismicity equations based on the rate- state friction nucleation of earthquake are well posited to characterize the aftershock distribution in regional assess- ments of earthquake probabilities.

关键词： Earthquake simulator Rate-and-stateseismicity Aftershock

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农田环境下无人机图像并行拼接识别算法

农业工程学报 2024年第9期40卷 154-163页

作者：许鑫张力岳继博钟鹤鸣王颖刘杰乔红波河南农业大学信息与管理科学学院郑州450002 全国农业推广技术服务中心北京100125

为改善在农田环境下无人机图像计算速度和效率,该研究提出了一种农田环境下无人机图像并行拼接识别算法。利用倒二叉树并行拼接识别算法,通过提取图像拼接中的变换矩阵,实现拼接识别同时进行。根据边缘设备的CPU核心数和图像数量自动将... 详细信息

为改善在农田环境下无人机图像计算速度和效率,该研究提出了一种农田环境下无人机图像并行拼接识别算法。利用倒二叉树并行拼接识别算法,通过提取图像拼接中的变换矩阵,实现拼接识别同时进行。根据边缘设备的CPU核心数和图像数量自动将图像拼接识别任务划分为多个子进程,并分配到不同核心上执行,以提高在农田环境下的计算效率。试验结果表明:相同试验环境和数据集条件下,倒二叉树并行拼接算法的拼接耗时相较于其他算法平均减少了60%~90%左右;在农田环境下,倒二叉树并行拼接识别相较于串行拼接识别的耗时减少了70%,图像识别的平均像素交并比提升了10.17个百分点,说明在农田环境下采用多线程倒二叉树并行算法可以更好地利用农田环境下边缘设备的计算资源,大幅提升无人机图像的拼接和识别的速度,为无人机的快速实时监测提供技术支撑。

关键词：无人机遥感图像处理全景拼接多核CPU 多进程

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Research on an Improved Dead Reckoning for AUV Navigation

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Research on an Improved Dead Reckoning for AUV Navigation

Heading constraint algorithm for foot-mounted PNS using low-cost IMU

2010 Chinese Control and Decision Conference

作者： Zheping Yan,Shuping Peng,Jiajia Zhou,Jian xu,heming Jia College of Automation,Harbin Engineering University,Harbin,150001

＜正＞It is difficult for Autonomous Underwater Vehicle（AUV） to satisfy the demand of long time navigation because of the installation angle’s deviation error as well as the measurement *** data collected by GPS were filtered using Extended Kalman Filter（EKF） prior to being utilized in the ***,the installation angle’s deviation error of DVL was *** paper does some deep research on the improved dead reckoning method, and the performance is evaluated using real data collected by an *** presented experimental results verify that the improved dead reckoning method can significantly enhance the accuracy of navigation,which for the vehicle position was estimated to be less than 0.5%both in north and east.

关键词： Autonomous Underwater Vehicle EKF Dead Reckoning Autonomous Navigation

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Journal of Systems Engineering and Electronics 2022年第3期33卷 727-736页

作者： GUI Jing ZHAO heming xu Xiang School of Electronic and Information Engineering Soochow UniversitySuzhou 215006China

Foot-mounted pedestrian navigation system(PNS)is a common solution to pedestrian navigation using micro-electro mechanical system(MEMS)inertial *** inherent problems of inertial navigation system(INS)by the traditional algorithm,such as the accumulated errors and the lack of observation of heading and altitude information,have become obstacles to the application and development of the *** this paper,we introduce a heuristic heading constraint *** of all,according to the movement characteristics of human gait,we use the generalized likelihood ratio test(GLRT)detector and introduce a time threshold to classify the human gait,so that we can effectively identify the stationary state of the *** addition,based on zero velocity update(ZUPT)and zero angular rate update(ZARU),the cumulative error of the inertial measurement unit(IMU)is limited and corrected,and then a heuristic heading estimation is used to constrain and correct the heading of the *** simulation and experiments with low-cost IMU,the method is proved to reduce the localization error of end-point to less than 1%of the total distance,and it has great value in application.

关键词： pedestrian navigation system(PNS) zero velocity update(ZUPT) gait detection heading constraint

前列腺癌风险性SNP rs55958994相关的增强子座位促进lncRNA HOTAIR表达增强肿瘤细胞迁移能力

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南开大学学报（自然科学版） 2022年第1期55卷 59-63,106页

作者：徐鹤铭钱俞羊赵忠芳石建党吕万革南开大学生命科学学院天津300071

长链非编码RNA(lncRNA)在恶性肿瘤发生发展中发挥重要的作用,其中lncRNA HOTAIR已经被证实能够促进多重肿瘤的转移.前期研究通过全基因组关联研究(GWAS)发现,12号染色体长臂13区13带(12q13.13)的SNP位点rs55958994是前列腺癌独立风险因... 详细信息

长链非编码RNA(lncRNA)在恶性肿瘤发生发展中发挥重要的作用,其中lncRNA HOTAIR已经被证实能够促进多重肿瘤的转移.前期研究通过全基因组关联研究(GWAS)发现,12号染色体长臂13区13带(12q13.13)的SNP位点rs55958994是前列腺癌独立风险因子,通过生物信息学分析发现含有该风险性SNP的染色体座位是一个潜在的增强子元件,在22Rv1细胞系中敲除该增强子座位发现肿瘤细胞的转移侵袭能力明显降低;采用Capture-C实验结合基因表达谱分析发现该增强子元件通过染色质长距离相互作用调节lncRNA HOTAIR的表达;进一步采用细胞分子生物学实验证实HOTAIR是该风险性增强子影响肿瘤进展的关键基因之一.

关键词： LncRNA HOTAIR 前列腺癌 SNP rs55958994

深井高地温条件下近距离煤层工作面回采期间防火技术研究

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煤炭技术 2022年第1期41卷 170-173页

作者：蒯多磊胡云强丁江海苏东忠徐鹤鸣李杰皖北煤电集团公司朱集西煤矿安徽淮南232098

为解决深井高地温条件下近距离煤层开采易导致采空区遗煤自燃的问题,基于近距离煤层,分析了工作面回采期间煤自燃危险区域,提出了"两道、两线、一断层"作为工作面防火的重点;结合近距离煤层的特点,在工作面回采期间,采取11501顶抽巷"劈... 详细信息

为解决深井高地温条件下近距离煤层开采易导致采空区遗煤自燃的问题,基于近距离煤层,分析了工作面回采期间煤自燃危险区域,提出了"两道、两线、一断层"作为工作面防火的重点;结合近距离煤层的特点,在工作面回采期间,采取11501顶抽巷"劈头浇"的方式灌浆、注液态CO_(2)(N_(2)),运输、轨道顺槽灌浆等综合预防性防火措施。结果表明:以11501顶抽巷防灭火钻孔灌浆、注液态CO_(2)(N_(2))为主,运输、轨道顺槽灌浆为辅的综合防火技术措施是有效的。通过在朱集西煤矿的现场应用,实现了工作面的安全顺利回采。

关键词：近距离煤层 11501顶抽巷防灭火钻孔劈头浇灌浆

Self-Affine Fractals and the Fractal Dimension of Fractured Rock Profiles

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Earthquake Research in China 1994年第3期8卷 12-18页

作者： Shi Xingjue,xu heming,Niu Zhiren and Fan ZengjieUniversity of Science and Technology of China,Hefei 230026,China Seismologicai Bureau of Shanxi,Xi’an 710068,China

The measured profiles of laboratory fractured rocks should be self-affine *** scaling properties of these profiles are described by two parameters-the fractal dimension D and the crossover length tc The D values of eight profiles are calculated by the ruler method and by the standard deviation method *** is shown that if tc is far greater than the sampling step tc two methods yield the same results,although if it is far smaller than r,the D by the standard method will be about 1.20,while D by the ruler method will very close to 1.0,because two fractal dimensions,local and global,exist on two sides of tc In order to obtain the local fractal dimension which may be close to that of the standard deviation method,the ruler method must be *** propose a way to estimate the tc and to modify the ruler ***,a profile having given D is generated in terms of the principle of non-integer order differential,through which the above two methods are verified and lead to the same

关键词： Self-Affine Fractal Ruler Method Crossover Length Standard Deviation Method

ZLDG—01高强度铸造铝合金的工艺与性能

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热加工工艺 1988年第3期 30-32页

作者：许鹤鸣国营四一一厂

本文研究了铸造、热处理等工艺参数对ZLDG—01铸造铝合金性能的影响,通过生产实践,为进一步提高该合金的性能,对其成分设计提出了改进意见。

关键词：变质处理成分设计熔炼机械性能力学性质铸态组织显微组织(金相学) ZLDG

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基于损伤本构的齿轮疲劳模型

机械强度 2017年第2期39卷 417-422页

作者：徐鹤鸣黄再兴强磊萧业南京航空航天大学机械结构力学及控制国家重点实验室南京210016

在损伤本构模型基础上,依据Lemaitre-Chaboche塑性损伤理论,建立了一种新的齿轮材料疲劳损伤模型,导出了齿轮材料的疲劳寿命理论方程,结果表明基于损伤本构的疲劳损伤模型正确反映了材料属性、三轴应力比、应力幅值水平对疲劳寿命的影响... 详细信息

在损伤本构模型基础上,依据Lemaitre-Chaboche塑性损伤理论,建立了一种新的齿轮材料疲劳损伤模型,导出了齿轮材料的疲劳寿命理论方程,结果表明基于损伤本构的疲劳损伤模型正确反映了材料属性、三轴应力比、应力幅值水平对疲劳寿命的影响,而且给出了这种新的理论疲劳理论模型算例验证,分析了该模型与传统名义应力S-N曲线形式的统一性,为预测齿轮材料的寿命提供了一种新的途径。

关键词：齿轮弯曲应力有限元分析 Lemaitre-Chaboche塑性损伤理论疲劳损伤模型疲劳寿命