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Trajectory optimisation in electrical discharge machining of three-dimensional curved and twisted channels

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Chinese Journal of Aeronautics 2022年第4期35卷 473-484页

作者： Jianshe zhao Yicong QIU Jian YUAN Chao LIU College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Laboratory of Integrated Electrical Processing Nanjing HANGPU Machinery Technology Company LimitedNanjing 210000China Military Representative Bureau of the Air Force Equipment Department in Shanghai and Military Representative Office in Zhuzhou Region Zhuzhou 412002China AECC South Industry Company Limited Zhuzhou 412002China

Numerical control electrical discharge machining(NC EDM) is one of the most widely used machining technologies for manufacturing a closed blisk flow path, particularly for three-dimensional(3D) curved and twisted flow channels. In this process, tool electrode design and machining trajectory planning are the key factors affecting machining accessibility and efficiency. Herein, to reduce the difficulty in designing the electrode and its motion path in the closed curved and twisted channels, a heuristic search hybrid optimisation strategy based on channel grids is adopted to realise the initial electrode trajectory design search and optimised size reduction. By transferring the trajectory optimisation constraints from the complex free-form surface to numbered grids, the search is found to be more orderly and accurate. The two trajectory indicators, namely argument angle and minimum distance, are analysed separately for the optimised results of the adaptive learning particle swarm optimisation algorithm, demonstrating that they can meet the actual processing *** results of NC EDM indicate that the motion path generated by this design method can meet the machining requirements of 3D curved and twisted flow channels.

关键词： Blisk Electrical discharge machining(EDM) Electrode Objective functions Trajectory generation

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19 世纪英国霍乱地图及其意义

史学集刊 2025年第2期 51页

作者：赵秀荣中国人民大学历史学院北京100872

19世纪30年代,随着霍乱在英国的流行,霍乱地图随之诞生。霍乱地图的出现,是英国制图技术进步、人口统计学发展、登记总署建立与人们对“可见性”痴迷的结果。19世纪中叶,托马斯·沙普特、奥古斯都·彼得曼、亨利·阿克兰及约翰·斯诺绘... 详细信息

19世纪30年代,随着霍乱在英国的流行,霍乱地图随之诞生。霍乱地图的出现,是英国制图技术进步、人口统计学发展、登记总署建立与人们对“可见性”痴迷的结果。19世纪中叶,托马斯·沙普特、奥古斯都·彼得曼、亨利·阿克兰及约翰·斯诺绘制的霍乱地图较具代表性。这一时期的霍乱地图具有空间性、可视性和专业性的特点,对公共健康、医学地理学及地图绘制技术的发展意义重大。与此同时,霍乱地图经常被作为当时流行的瘴气论的依据,具有时代局限性。

关键词：英国霍乱地图传染病医疗社会史

Adaptive navigation assistance based on eye movement features in virtual reality

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Virtual Reality & Intelligent Hardware 2023年第3期5卷 232-248页

作者： Song zhao Shiwei CHENG School of Computer Science and Technology Zhejiang University of TechnologyHangzhou 310023China

Background Navigation assistance is essential for users when roaming virtual reality scenes;however,the traditional navigation method requires users to manually request a map for viewing,which leads to low immersion and poor user *** To address this issue,we first collected data on who required navigation assistance in a virtual reality environment,including various eye movement features,such as gaze fixation,pupil size,and gaze ***,we used the boosting-based XGBoost algorithm to train a prediction model and finally used it to predict whether users require navigation assistance in a roaming *** After evaluating the performance of the model,the accuracy,precision,recall,and F1-score of our model reached approximately 95%.In addition,by applying the model to a virtual reality scene,an adaptive navigation assistance system based on the real-time eye movement data of the user was *** Compared with traditional navigation assistance methods,our new adaptive navigation assistance method could enable the user to be more immersive and effective while roaming in a virtual reality(VR)environment.

关键词： Eye movement Navigation Human-computer interaction Virtual reality Eye tracking

Hard X-ray free-electron laser based on echo-enabled staged harmonic generation scheme

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Chinese Science Bulletin 2010年第3期55卷 221-227页

作者： FENG Chao zhao ZhenTang Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

A novel approach to producing coherent hard X-ray based on the echo-enabled staged harmonic generation (EESHG) free-electron laser scheme is proposed. This scheme is not a simple cascaded echo-enabled harmonic generation (EEHG) but consists of an EEHG and a conventional high-gain harmonic generation (HGHG) like configuration, which also works in the EEHG principle. It is shown that fully coherent hard X-ray radiation can be obtained directly from a conventional VUV seed laser with reduced size and cost in comparison with the self-amplified spontaneous emission (SASE) based hard X-ray facilities.

关键词：硬X射线辐射自由电子激光谐波产生激光回波放大的自发辐射种子激光真空紫外高增益

Fiducial Approach for the Storage Reliability Assessment of Complex Repairable Systems

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Journal of Systems Science & Complexity 2024年第4期37卷 1653-1671页

作者： YANG Yang zhao Letian CHEN Siyi YU Dan University of Chinese Academy of Sciences Beijing 100190China Computer Application Institute of Nuclear Industry Beijing 100142China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China

In recent years,there has been a growing focus on high-reliability products in industrial and military *** plays a crucial role in these products,and as a result,research on storage reliability has gained more *** paper specifically targets a class of products with complex structures that require long-term storage,regular testing,and ***,an expression method for system availability is provided based on the reliability structure of the system and the maintenance situation of the constituent equipment in *** the expression of system availability is typically complex and difficult to compute,and the storage life of the system cannot be represented as an explicit function of the reliability indicators of the constituent equipment,it is challenging to evaluate the availability and storage life of repairable *** address this,the paper proposes a comprehensive evaluation methodology for assessing the storage reliability of complex repairable systems based on fiducial *** approach is employed to derive point estimates and determine the lower fiducial limits for both system availability and storage ***,simulation results demonstrate that this comprehensive evaluation method for storage reliability of complex repairable systems is not only convenient but also highly effective.

关键词： Availability fiducial method repairable system storage life

Highly transparent, antifreezing and stretchable conductive organohydrogels for strain and pressure sensors

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Science China(Technological Sciences) 2021年第11期64卷 2532-2540页

作者： zhao Rui YANG Han NIE BaoQing HU Liang State Key Laboratoiy of Radiation Medicine and Protection School for Radiological and Interdisciplinary Sciences(RAD-X)and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education InstitutionsSoochow UniversitySuzhou 215123China Medical Image Processing Analysis and Visualization(MIPAV)School of Electronic and Information EngineeringSoochow UniversitySuzhou 215006China

Conductive hydrogels are good candidates for flexible wearable sensors, which have received considerable attention for use in human-machine interfaces, human motion/health monitoring, and soft robots. However, these hydrogels often freeze at low temperatures and thus, exhibit low transparency, weak mechanical strength and stretchability, as well as poor adhesion *** this paper, conductive organohydrogels were prepared by thermal polymerization of acrylamide and N-(3-aminopropyl)methacrylamide in a glycerol-water binary solvent using Na Cl as a conductive salt. Compared to other organohydrogels, our organohydrogels featured higher fracture stress(170 kPa) and greater stretchability(900%). The organohydrogels showed excellent antifreezing properties and high transparency(97%, at 400–800 nm wavelength) and presented outstanding adhesion strength to a variety of substrates. The conductive organohydrogels that were stored at -20℃ for 24 h could still respond to both strain and pressure, showing a high sensitivity(gauge factor=2.73 under 100% strain), fast response time(0.4 s), and signal repeatability during multiple force cycles(~100 cycles). Furthermore, the conductivity of cleaved antifreezing gels could be restored by contacting the broken surfaces together. Finally, we used our organohydrogels to monitor human tremors and bradykinesia in real-time within wired and wireless models, thus presenting a potential application for Parkinson’s disease diagnosis.

关键词： organohydrogels transparency antifreezing stretchability conductive sensors

Functional Multiple-Outcome Model in Application to Multivariate Growth Curves of Infant Data

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Journal of Systems Science & Complexity 2021年第4期34卷 1555-1577页

作者： YAN Xingyu ZHOU Yingchun PU Xiaolong zhao Peng School of Mathematics and Statistics Jiangsu Normal UniversityXuzhou 221116China Key Laboratory of Advanced Theory and Application in Statistics and Data Science-MOE School of StatisticsEast China Normal UniversityShanghai 200062China

Motivated by a medical study that attempts to analyze the relationship between growth curves and other variables and to measure the association among multiple growth curves,the authors develop a functional multiple-outcome model to decompose the total variation of multiple functional outcomes into variation explained by independent variables with time-varying coefficient functions,by latent factors and by *** latent factors are the hidden common factors that influence the multiple outcomes and are found through the combined functional principal component analysis *** the coefficients of the latent factors one may further explore the association of the multiple *** method is applied to the multivariate growth data of infants in a real medical study in Shanghai and produces interpretable *** rates for the proposed estimates of the varying coefficient and covariance functions of the model are derived under mild conditions.

关键词： Convergence rate functional data functional principal components growth curve multiple outcomes

A Comprehensive Survey on STP Approach to Finite Games

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Journal of Systems Science & Complexity 2021年第5期34卷 1666-1680页

作者： CHENG Daizhan WU Yuhu zhao Guodong FU Shihua Key Laboratory of Systems and Control Academy of Mathematics and Systems SciencesChinese Academy of SciencesBeijing 100190China. Key Laboratory of Intelligent Control and Optimization for Industrial Equipment of Ministry of Education Dalian University of TechnologyDalian 116081China School of Mathematics and Statistics Shandong Normal UniversityJinan 250014China. School of Mathematical Sciences Liaocheng UniversityLiaocheng 252000China

Nowadays the semi-tensor product(STP)approach to finite games has become a promising new *** paper provides a comprehensive survey on this prosperous *** a brief introduction for STP and finite(networked)games,a description for the principle and fundamental technique of STP approach to finite games is *** several problems and recent results about theory and applications of finite games via STP are presented.A brief comment about the potential use of STP to artificial intelligence is also proposed.

关键词： Finite game game-theoretic control potential game semi-tensor product vector space structure of finite game

Plasma-exfoliated g-C_(3)N_(4) with oxygen doping: tailoring photocatalytic properties

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Frontiers of Chemical Science and Engineering 2024年第2期18卷 27-39页

作者： Yuxin Li Junxin Guo Rui Han zhao Wang National Engineering Research Centre of Industry Crystallization Technology School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

Heteroatom doping and defect engineering have been proposed as effective ways to modulate the energy band structure and improve the photocatalytic activity of g-C_(3)N_(4). In this work, ultrathin defective g-C_(3)N_(4) was successfully prepared using cold plasma. Plasma exfoliation reduces the thickness of g-C_(3)N_(4) from 10 nm to 3 nm, while simultaneously introducing a large number of nitrogen defects and oxygen atoms into g-C_(3)N_(4). The amount of doped O was regulated by varying the time and power of the plasma treatment. Due to N vacancies, O atoms formed strong bonds with C atoms, resulting in O doping in g-C_(3)N_(4). The mechanism of plasma treatment involves oxygen etching and gas expansion. Photocatalytic experiments demonstrated that appropriate amount of O doping improved the photocatalytic degradation of rhodamine B compared with pure g-C_(3)N_(4). The introduction of O optimized the energy band structure and photoelectric properties of g-C_(3)N_(4). Active species trapping experiments revealed ·O_(2)^(–) as the main active species during the degradation.

关键词： graphitic carbon nitride cold plasma oxygen doping nitrogen defect visible-light photocatalysis