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Acta Mechanica Sinica 2010年第2期26卷 279-288页

作者： Lei jin shijie Xu Department of Guidance Navigation and Control School of Astronautics Beihang University 100191 Beijing China

Angular velocity stabilization control and attitude stabilization control for an underactuated spacecraft using only two single gimbal control moment gyros （SGCMGs） as actuators is investigated. First of all, the dynamic model of the underactuated spacecraft is established and the singularity of different configurations with the two SGCMGs is analyzed. Under the assumption that the gimbal axes of the two SGCMGs are installed in any direction, and that the total system angular momentum is not zero, a state feedback control law via Lyapunov method is designed to globally asymptotically stabilize the angular velocity of spacecraft. Under the assumption that the gimbal axes of the two SGCMGs are coaxially installed along anyone of the three principal axes of spacecraft inertia, and that the total system angular momentum is zero, a discontinuous state feedback control law is designed to stabilize three-axis attitude of spacecraft with respect to the inertial frame. Furthermore, the singularity escape of SGCMGs for the above two control problems is also studied. Simulation results demonstrate the validity of the control laws.

关键词： Single gimbal control moment gyro ·Undcractuated spacecraft · Angular velocity stabilization · Three-axis attitude stabilization·Singularity

Resolution Enhancement in Ultrasonic TOFD Imaging by Combining Sparse Deconvolution and Synthetic Aperture Focusing Technique(Sparse-SAFT)

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Chinese Journal of Mechanical Engineering 2022年第5期35卷 141-149页

作者： Xu Sun Li Lin shijie jin School of Materials Science and Engineering Dalian University of TechnologyDalianChina

The shallow subsurface defects are difficult to be identified and quantified by ultrasonic time-of-flight diffraction(TOFD)due to the low resolution induced by pulse width and beam *** this paper,Sparse-SAFT is proposed to improve the time resolution and lateral resolution in TOFD imaging by combining sparse deconvolution and synthetic aperture focusing technique(SAFT).The mathematical model in the frequency domain is established based on the l1 and l2 norm constraints,and the optimization problem is solved for enhancing time *** this basis,SAFT is employed to improve lateral resolution by delay-and-sum *** simulated and experimental results indicate that the lateral wave and tip-diffracted waves can be decoupled with *** shallow subsurface defects with a height of 3.0 mm at the depth of 3.0 mm were detected quantitatively,and the relative measurement errors of flaw heights and depths were no more than 10.3%.Compared to conventional SAFT,the time resolution and lateral resolution are enhanced by 72.5 and 56%with Sparse-SAFT,***,the proposed method is also suitable for improving resolution to detect the defects beyond dead zone.

关键词： Time resolution Lateral resolution Time-of-flight diffraction(TOFD) Sparse deconvolution Synthetic aperture focusing technique(SAFT) Sparse-SAFT

TOFD detection of shallow subsurface defects in aluminum alloy thin plates by half-skip mode-converted wave

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Chinese Journal of Aeronautics 2024年第6期37卷 454-463页

作者： shijie jin Zhicheng WANG Zhongbing LUO NDT&E Laboratory Dalian University of TechnologyDalian 116085China

Aluminum alloy is widely applied to the aerospace ***,the inspection of thin plates using Time-of-Flight Diffraction(TOFD)technique is restricted by the near-surface dead zone because of the coupling between diffracted longitudinal wave and lateral *** halfskip mode-converted wave is introduced to decrease dead zone and detect defects in aluminum alloy thin plates by increasing ray path and propagation *** quantitative correlation for the diffracted shear wave from longitudinal back-wall wave is deduced in combination with the acoustic path,realizing the accurate location of shallow subsurface *** and experimental results indicate that the dead zone is decreased by 38% by the half-skip mode-converted wave,and the location errors are within 5% for the aluminum alloy plate with a thickness of 7.0 *** to other alternative TOFD techniques,half-skip mode-converted wave has better response amplitude and positioning accuracy,demonstrating strong applicability in TOFD inspection of thin plates.

关键词： Ultrasonic testing Time-of-Flight Diffraction(TOFD) Dead zone Half-skip mode-converted wave Quantitative detection

Improving Ultrasonic Testing by Using Machine Learning Framework Based on Model Interpretation Strategy

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Chinese Journal of Mechanical Engineering 2023年第5期36卷 174-186页

作者： Siqi Shi shijie jin Donghui Zhang jingyu Liao Dongxin Fu Li Lin NDT&E Laboratory Dalian University of TechnologyDalian 116024China China Nuclear Industry 23 Construction Co. Ltd.Beijing 101300China

Ultrasonic testing(UT)is increasingly combined with machine learning(ML)techniques for intelligently identifying *** signifcant features from UT data is essential for efcient defect ***,the hidden physics behind ML is unexplained,reducing the generalization capability and versatility of ML methods in *** this paper,a generally applicable ML framework based on the model interpretation strategy is proposed to improve the detection accuracy and computational efciency of ***,multi-domain features are extracted from the UT signals with signal processing techniques to construct an initial feature ***,a feature selection method based on model interpretable strategy(FS-MIS)is innovatively developed by integrating Shapley additive explanation(SHAP),flter method,embedded method and wrapper *** most efective ML model and the optimal feature subset with better correlation to the target defects are determined *** proposed framework is validated by identifying and locating side-drilled holes(SDHs)with 0.5λcentral distance and different *** ultrasonic array probe is adopted to acquire FMC datasets from several aluminum alloy specimens containing two SDHs by *** optimal feature subset selected by FS-MIS is set as the input of the chosen ML model to train and predict the times of arrival(ToAs)of the scattered waves emitted by adjacent *** experimental results demonstrate that the relative errors of the predicted ToAs are all below 3.67%with an average error of 0.25%,signifcantly improving the time resolution of UT *** this basis,the predicted ToAs are assigned to the corresponding original signals for decoupling overlapped pulse-echoes and reconstructing high-resolution FMC *** imaging resolution is enhanced to 0.5λby implementing the total focusing method(TFM).The relative errors of hole depths and central distance are no more than 0.51%and 3.57%,***

关键词： Ultrasonic testing Machine learning Feature extraction Feature selection Shapley additive explanation

An improved constrained steering law for SGCMGs with DPC

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Acta Mechanica Sinica 2009年第5期25卷 713-720页

作者： Lei jin shijie Xu Department of Guidance, Navigation and Control,School of Astronautics, Beihang University, 100191 Beijing, China Department of Guidance Navigation and Control School of Astronautics Beihang University 100191 Beijing China

An improved constrained （IC） steering law for single gimbal control moment gyros （SGCMGs） with deformed pyramid configuration （DPC） is proposed, First of all, the original system with five pyramid configuration （FPC） whose two adjacent gyros are in failure state is reconfigured as a degraded system with DPC. Then, the singular angular momentum hypersurfaces of the original and the degraded systems are plotted via the singular angular momentum equa- tion of SGCMGs. Based on singular surfaces, the differences between FPC and DPC in singularity and momentum envelope are obtained directly, which provide an important reference for steering law design of DPC. Finally, an IC steering law is designed and applied to DPC. The simulation results demonstrate that the IC steering law has advantages in simplicity of calculation, avoidance of singularity and exactness of output torque, which endow the degraded system with fine controllability in a restricted workspace.

关键词： Single gimbal control moment gyros (SGCMGs) - Deformed pyramid configuration (DPC) Failure Singularity - Steering law

Emerging new therapeutic antibody derivatives for cancer treatment

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Signal Transduction and Targeted Therapy 2022年第3期7卷 638-665页

作者： shijie jin Yanping Sun Xiao Liang Xinyu Gu Jiangtao Ning Yingchun Xu Shuqing Chen Liqiang Pan Institute of Drug Metabolism and Pharmaceutical Analysis College of Pharmaceutical SciencesZhejiang University310058 HangzhouChina Department of Precision Medicine on Tumor Therapeutics ZJU-Hangzhou Global Scientific and Technological Innovation Center311200 HangzhouChina The First Affiliated Hospital Zhejiang University School of Medicine310003 HangzhouChina Key Laboratory of Pancreatic Disease of Zhejiang Province 310003 HangzhouChina

Monoclonal antibodies constitute a promising class of targeted anticancer agents that enhance natural immune system functions to suppress cancer cell activity and eliminate cancer *** successful application of IgG monoclonal antibodies has inspired the development of various types of therapeutic antibodies,such as antibody fragments,bispecific antibodies,and antibody derivatives(e.g.,antibody-drug conjugates and immunocytokines).

关键词： therapeutic cancer antibodies

TCR-mimic antibody-drug conjugates targeting intracellular tumor-specific mutant antigen KRAS G12V mutation

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Asian Journal of Pharmaceutical Sciences 2020年第6期15卷 777-785页

作者： Ying Shen Xiaoyue Wei shijie jin Yue Wu Wenbin Zhao Yingchun Xu Liqiang Pan Zhan Zhou Shuqing Chen College of Pharmaceutical Sciences Zhejiang UniversityHangzhou 310058China Huabo Biopharm Co. Ltd.Shanghai 201203China

Limited clinical application of antibody-drug conjugates(ADCs)targeting tumor associated antigens(TAAs)is usually caused by on-target off-tumor side ***-specific mutant antigens(TSMAs)only expressed in tumor cells which are ideal targets for *** addition,intracellular somatic mutant proteins can be presented on the cell surface by human leukocyte antigen class I(HLA I)molecules forming tumor-specific peptide/HLA I *** G12 V mutation frequently occurred in varied cancer and was verified as a promising target for cancer *** this study,we generated two TCR-mimic antibodydrug conjugates(TCRm-ADCs),2E8-MMAE and 2 A5-MMAE,targeting KRAS G12 V/HLAA*0201 complex,which mediated specific antitumor activity in vitro and in vivo without obvious *** findings are the first time validate the strategy of TCRm-ADCs targeting intracellular TSMAs,which improves the safety of antibody-based drugs and provides novel strategy for precision medicine in cancer therapy.

关键词： TCR-mimic antibody-drug conjugates Tumor-specific mutant antigens KRAS G12V Human leukocyte antigen classⅠ

套管-水泥界面微间隙厚度的低频超声反演方法

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声学学报 2014年第4期39卷 467-472页

作者：韩炜毛捷金士杰中国科学院声学研究所声场声信息国家重点实验室北京100190

研究了应用低频超声垂直入射反射波实现套管-水泥界面流体微间隙薄层厚度的反演方法。应用灵敏度函数比较分析了分层系统反射谱各阶谐振频率处的相位跳变量较之各阶谐振频率作为反演特征量的优势。通过目标函数分析,选取分层系统3~10阶... 详细信息

研究了应用低频超声垂直入射反射波实现套管-水泥界面流体微间隙薄层厚度的反演方法。应用灵敏度函数比较分析了分层系统反射谱各阶谐振频率处的相位跳变量较之各阶谐振频率作为反演特征量的优势。通过目标函数分析,选取分层系统3~10阶谐振频率处相位跳变量作为特征量,利用BP神经网络实验获得0.1~1.0 mm内不同间隙层厚度的反演结果。反演结果与真实值的平均相对误差为4.6%,最小反演厚度仅为波长的18%。所选取的相位特征量也可用于其它层状高声阻抗介质下的薄层厚度反演。

关键词：低频超声反演方法微间隙相位跳变谐振频率函数分析相位特征特征量分层系统平均相对误差

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铝合金搅拌摩擦焊超声检测研究进展

材料工程 2022年第8期50卷 45-59页

作者：金士杰田鑫林莉大连理工大学无损检测研究所辽宁大连116024

铝合金搅拌摩擦焊(friction stir welding, FSW)焊接参数选择不当将会产生隧道孔、未焊透(lack of penetration, LOP)和吻接等取向复杂、细微紧贴的缺陷。首先,本文简述了FSW焊缝与典型缺陷特征,总结了超声检测时面临纵向分辨力低、缺... 详细信息

铝合金搅拌摩擦焊(friction stir welding, FSW)焊接参数选择不当将会产生隧道孔、未焊透(lack of penetration, LOP)和吻接等取向复杂、细微紧贴的缺陷。首先,本文简述了FSW焊缝与典型缺陷特征,总结了超声检测时面临纵向分辨力低、缺陷表征不完整、材料与缺陷声阻抗接近和灵敏度不足等难点。随后,从常规超声、超声衍射时差法(time-of-flight diffraction, TOFD)、相控阵超声检测技术和其他超声检测技术等方面综述了现有的铝合金FSW超声检测研究工作。最后,结合超声信号处理方法和机器学习方法对研究前景进行展望:可以通过分析和提取信号特征,进一步提升超声检测分辨力和信噪比,并实现取向复杂缺陷和细微紧贴缺陷的精准辨识与定量。

关键词：搅拌摩擦焊铝合金超声检测缺陷

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Updated prevalence of latent prostate cancer in Chinese population and comparison of biopsy results: An autopsy-based study

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The Innovation 2024年第1期5卷 80-87页

作者： Yuliang Chen Zhien Zhou Yi Zhou Zhipeng Mai shijie jin Zhen Liang Zhiyuan Shang Yuzhi Zuo Yu Xiao Wenze Wang Haibo Wang Weigang Yan Department of Urology Peking Union Medical College HospitalChinese Academy of Medical SciencesBeijing 100730China Department of Gynaecology and Obstetrics Beijing HospitalNational Centre of GerontologyBeijing 100730China Department of Pathology Peking Union Medical College HospitalChinese Academy of Medical SciencesBeijing 100730China Peking University Clinical Research Institute Peking University First HospitalBeijing 100034China

Prostate cancer detected by autopsy is named latent prostate *** the repertoire of clinical prostate cancer,latent cancer may better reflect the disease *** clinical prostate specimens,which are obtained exclusively from biopsy-positive cases,prostate specimens obtained through autopsy provide information on biopsy-negative cases,helping calculate the true sensitivity of prostate *** 2014 to 2021,we collected autopsy specimens of the prostate from body donors in China and performed transperineal and transrectal biopsies on specimens before step-sectioning and pathological *** found that the crude prevalence of latent prostate cancer in middle-aged and elderly men was 35.1%(81/231),which was higher than previous estimates for Chinese *** overall per-patient sensitivities of transperineal and transrectal biopsies were not significantly different(33.3%vs.32.1%,p=0.82),but the two approaches differed in preferential sampling area along the proximal-distal axis of the *** biopsy had a higher sensitivity for detecting clinically significant lesions in the distal third(34.7%vs.16.3%,p=0.02)and distal half(30.6%vs.18.1%,p=0.04),while transrectal biopsy had a higher sensitivity for lesions in the proximal half(25.0%vs.13.9%,p=0.046).Both transperineal and transrectal methods of biopsy missed most small lesions(0.5 mL).In conclusion,the prevalence of latent prostate cancer in China has increased over the past 2 *** transperineal and transrectal methods of biopsy had comparable sensitivities but had different preferential sampling *** approaches miss one-third of large lesions.

关键词： biopsy prevalence latent