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Advancing large-scale thin-film PPLN nonlinear photonics with segmented tunable micro-heaters

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Photonics Research 2024年第8期12卷 1703-1708页

作者： XIAOTING LI HAOCHUAN LI ZHENZHENG WANG ZHAOXI CHEN FEI MA KE ZHANG WENZHAO SUN CHENG WANG Department of Electrical Engineering City University of Hong KongHong KongChina School of Physics Sun Yat-sen UniversityGuangzhou 510275China City University of Hong Kong(Dongguan) Dongguan 523808China Center of Information and Communication Technology City University of Hong Kong Shenzhen Research InstituteShenzhen 518057China State Key Laboratory of Terahertz and Millimeter Waves City University of Hong KongHong KongChina

Thin-film periodically poled lithium niobate(TF-PPLN)devices have recently gained prominence for efficient wavelength conversion processes in both classical and quantum ***,the patterning and poling of TF-PPLN devices today are mostly performed at chip scales,presenting a significant bottleneck for future largescale nonlinear photonic systems that require the integration of multiple nonlinear components with consistent performance and low ***,we take a pivotal step towards this goal by developing a wafer-scale TF-PPLN nonlinear photonic platform,leveraging ultraviolet stepper lithography and an automated poling *** address the inhomogeneous broadening of the quasi-phase matching(QPM)spectrum induced by film thickness variations across the wafer,we propose and demonstrate segmented thermal optic tuning modules that can precisely adjust and align the QPM peak wavelengths in each *** the segmented micro-heaters,we show the successful realignment of inhomogeneously broadened multi-peak QPM spectra with up to 57%enhancement of conversion *** achieve a high normalized conversion efficiency of 3802%W-1cm-2in a 6 mm long PPLN waveguide,recovering 84%of the theoretically predicted efficiency in this *** advanced fabrication techniques and segmented tuning architectures presented herein pave the way for wafer-scale integration of complex functional nonlinear photonic circuits with applications in quantum information processing,precision sensing and metrology,and low-noise-figure optical signal amplification.

关键词： tuning tunable waveguide

Studying the co-evolution of information diffusion,vaccination behavior and disease transmission in multilayer networks with local and global effects

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Chinese Physics B 2024年第3期33卷 677-689页

作者：霍良安武兵杰 Business School University of Shanghai for Science and TechnologyShanghai 200093China School of Intelligent Emergency Management University of Shanghai for Science and TechnologyShanghai 200093China

today,with the rapid development of the internet,a large amount of information often accompanies the rapid transmission of disease outbreaks,and increasing numbers of scholars are studying the relationship between information and the disease transmission process using complex *** fact,the disease transmission process is very *** this information,there will often be individual behavioral measures and other factors to *** of the previous research has aimed to establish a two-layer network model to consider the impact of information on the transmission process of disease,rarely divided into information and behavior,*** carry out a more in-depth analysis of the disease transmission process and the intrinsic influencing mechanism,this paper divides information and behavior into two layers and proposes the establishment of a complex network to study the dynamic co-evolution of information diffusion,vaccination behavior,and disease *** is achieved by considering four influential relationships between adjacent layers in multilayer *** the information layer,the diffusion process of negative information is described,and the feedback effects of local and global vaccination are *** the behavioral layer,an individual's vaccination behavior is described,and the probability of an individual receiving a vaccination is influenced by two factors:the influence of negative information,and the influence of local and global disease *** the disease layer,individual susceptibility is considered to be influenced by vaccination *** state transition equations are derived using the micro Markov chain approach(MMCA),and disease prevalence thresholds are *** is demonstrated through simulation experiments that the negative information diffusion is less influenced by local vaccination behavior,and is mainly influenced by global vaccination behavior;vaccination behavior is mainly influenced by local d

关键词： information diffusion vaccination behavior disease transmission multilayer networks local and global effect

Changes of china’s Status in the Global System and Its Influencing Factors:A Multiple Contact Networks Perspective

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Chinese Geographical Science 2024年第2期34卷 265-279页

作者： LIU Jian LIU Jibin YANG Qingshan CAI Sikai LIU Jie School of Geographical Sciences Northeast Normal UniversityChangchun 130024China Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains Ministry of EducationChangchun 130024China School of Architecture and Planning Jilin Jianzhu UniversityChangchun 130118China School of Geographical Sciences Liaoning Normal UniversityDalian 116029China

Clarifying china’s position in the global system is an important logical basis for developing national *** much research has been done on china’s development status,most studies have been based on country comparisons or institutional *** today’s networked era in which the global economy,trade,personnel,and information are closely connected,studies on china’s global position and its status changes and influencing factors in multiple contact networks are still *** this study,from the perspective of diverse global contact networks,we constructed economic,cultural,and political influence indices to explore the changes and influencing factors on china’s status in the global system from 2005 to *** results show that during the study period,china’s global influence in the fields of economic ties,cultural exchanges,and political contacts increased significantly,but its influ-ence in the fields of cultural exchanges and political contacts lagged far economic *** pattern of china’s economic influence on various economies around the world has shown a transformation from an‘upright pyramid’to an‘inverted pyramid’*** proportion of these economies in low-influence zones has decreased from more than 60%in 2005 to less than 20%in ***’s cultural and political influence on various economies around the world has increased significantly;however,for the former,the percentage of high-influence areas is still less than 20%,whereas for the latter the percentage of these economies in medium-and high-influence areas is still less than 50%.Analyses such as a scatter plot matrix show that geographical proximity,economic globalization,close cooperation with developing countries,and a proactive and peaceful foreign policy are important factors in improving china’s status in the diverse global network system.

关键词： global system economic ties cultural exchanges political contacts multiple contact networks china’s status

Design and Verification of Parallel Hip Exoskeleton Considering Output Torque Anisotropy

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Journal of Bionic Engineering 2024年第3期21卷 1305-1320页

作者： Jilong Xu Yunzhan Niu Fucai Liu Engineering Research Center of the Ministry of Education for Intelligent Control System and Intelligent Equipment Yanshan UniversityQinhuangdao066004China Key Laboratory of Industrial Computer Control Engineering of Heibei Province Yanshan UniversityQinhuangdao066004China College of Mechanical Engineering Yanshan UniversityQinhuangdao066004China

In rehabilitation training,it is crucial to consider the compatibility between exoskeletons and human legs in ***,most exoskeletons today adopt an anthropomorphic serial structure,which results in rotational centers that are not precisely aligned with the center of the hip *** address this issue,we introduce a novel exoskeleton called the Parallel Hip Exoskeleton(PH-Exo)in this ***-Exo is meticulously designed based on the anisotropic law of output *** the friction of the drive components,a dynamic model of the human-machine complex is *** analysis demonstrates that PH-Exo not only exhibits outstanding torque performance but also achieves high controllability in both flexion/extension and adduction/abduction ***,a robust controller is designed to address model uncertainty,friction,and external *** experiments indicate that under the control of the robust controller,each motor achieves excellent tracking performance.

关键词： Hip exoskeleton Parallel mechanism Misalignment Anisotropy Output torque

The trajectory of rice from wild to domesticated:A new chapter in the study of origins of agriculture

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Science china Earth Sciences 2024年第9期67卷 3011-3012页

作者： Zhijun ZHAO Institute of Cultural Heritage Shandong UniversityQingdao 266237China

Rice(Oryza sativa)is one of the most important food crops in the world today,feeding more than one-third of the global *** domestication of rice has always been an international research topic(Gross and Zhao,2014).When,where,and how rice was cultivated and eventually domesticated has been a hot issue in many research fields such as archaeology,biology,and agronomy(Fuller et al.,2009).

关键词： sativa Oryza crops

Research on Pulsar Time Steered Atomic Time Algorithm Based on DPLL

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Research in Astronomy and Astrophysics 2024年第3期24卷 237-248页

作者： Ze-Hao Zheng Yang Liu Dan Shen Fan Feng Jiu-Long Liu Yue-Xin Ma Xiang-Wei Zhu School of Electronic and Communication Engineering Sun Yat-sen UniversityShenzhen 518107China School of Aeronautics and Astronautics Sun Yat-sen UniversityShenzhen 518107China School of Systems Science and Engineering Sun Yat-sen UniversityGuangzhou 510275China

In today’s society,there is a wide demand for high-precision and high-stability time service in the fields of electric power,communication,transportation and *** present,the time standard in various countries is mainly based on atomic clocks,but the frequency drift of atomic clocks will affect the long-term stability *** with atomic clocks,millisecond pulsars have better long-term stability and can complement with the excellent short-term stability of atomic *** order to improve the long-term stability of the atomic timescale,and then improve the timing accuracy,this paper proposes an algorithm for steering the atomic clock ensemble(ACE)by ensemble pulsar time(EPT)based on digital phase locked loop(DPLL).First,the ACE and EPT are generated by the ALGOS algorithm,then the ACE is steered by EPT based on DPLL to calibrate the long-term frequency drift of the atomic clock,so that the generated steered atomic time follows both the short-term stability characteristics of ACE and the long-term stability characteristics of EPT,and finally,the steered atomic time is used to calibrate the local cesium *** experimental results show that the long-term stability of atomic time after steering is improved by 2 orders of magnitude compared with that before steering,and the daily drift of a local cesium clock after calibration is less than 9.47 ns in 3 yr,3 orders of magnitude higher than that before calibration on accuracy.

关键词： (stars) pulsars general-time-methods data analysis-instabilities

Hydrothermal liquefaction of biomass for jet fuel precursors:A review

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Chinese Chemical Letters 2024年第8期35卷 36-49页

作者： Shengfei Dong Ziyu Liu Xiaoyi Yang School of Energy and Power Engineering Energy and Environment International CentreBeihang UniversityBeijing 100191China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China

Climate change is an important issue facing the world today and carbon reduction has become the fo-cus of attention for all *** bio-fuels are an important means to achieve carbon emis-sion *** production of jet fuel precursors from biomass by hydrothermal liquefaction(HTL)has received a lot of attention due to its mild conditions and environmental *** biomass and algal biomass are considered as the second and the third generation biomasses as promising raw materials for alternative fuel *** them,lignocellulosic biomass has been extensively studied due to its wide range of sources and can be divided into one-step HTL and stepwise HTL accord-ing to the process *** biomass has been extensively studied experimentally due to its short growth cycle and the fact that it can sequester large amounts of carbon without taking up arable *** this paper,the feedstock composition of different biomasses is reviewed for the HTL of biomass.A detailed review of the process characteristics,reaction pathways and influencing factors for the HTL pro-duction of jet fuel precursors from lignocellulosic biomass and algal biomass is also *** references are provided for further process optimization and bio-crude quality upgrading.

关键词： Hydrothermal liquefaction(HTL) Lignocellulosic biomass Microalgae Bio-crude Jet fuel precursors

Microwave-accelerated direct regeneration of LiCoO_(2)cathodes for Li-ion batteries

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Science china Chemistry 2024年第7期67卷 2181-2189页

作者： Xueshan Hu Yun-Chao Yin Chao Li Lihui Zhou Lin Yang Yitian Feng Daxian Zuo Chenhui Ning Das Soham Sheng Dai Longbin Qiu Lin Zeng Haw Jiunn Woo Jiayu Wan Future Battery Research Center Global Institute of Future TechnologyShanghai Jiao Tong UniversityShanghai 200240China Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen 518055China Centre for Ionics University of Malaya Department of PhysicsFaculty of ScienceUniversity of MalayaKuala Lumpur 50603Malaysia Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China Department of Natural and Applied Sciences Duke Kunshan UniversityKunshan 215316China

Recycling spent lithium-ion batteries is integral to today's low-carbon environmental protection *** concept of direct regeneration,acknowledged for its environmental sustainability,economic viability,and consistent performance of recycled materials,is gaining *** study presents an efficient and nondestructive approach by utilizing an ultrafast microwave technology to directly regenerate spent lithium cobaltate(LCO)cathode *** contrast to conventional furnacebased processes,this method significantly reduces the regeneration *** subjecting the spent LCO mixed with lithium sources to three microwave heating cycles(at approximately 1,350 K),LCO regeneration is achieved,yielding a specific capacity of 140.8 mAh g^(-1)(0.2 C)with a robust cycle *** further environmental and economic benefits,the ultrafast microwave technology holds scientific promise for directly regenerating cathode materials,while establishing competitiveness for industrial applications.

关键词： battery recycling spent lithium cobaltate microwave directly regeneration cathode materials

Maximum Correntropy Criterion-Based UKF for Loosely Coupling INS and UWB in Indoor Localization

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 2673-2703页

作者： Yan Wang You Lu Yuqing Zhou Zhijian Zhao Department of Computer and Communication Engineering Northeastern UniversityQinhuangdao066004China

Indoor positioning is a key technology in today’s intelligent environments,and it plays a crucial role in many application *** paper proposed an unscented Kalman filter(UKF)based on the maximum correntropy criterion(MCC)instead of the minimummean square error criterion(MMSE).This innovative approach is applied to the loose coupling of the Inertial Navigation System(INS)and Ultra-Wideband(UWB).By introducing the maximum correntropy criterion,the MCCUKF algorithm dynamically adjusts the covariance matrices of the system noise and the measurement noise,thus enhancing its adaptability to diverse environmental localization *** in the presence of non-Gaussian noise,especially heavy-tailed noise,the MCCUKF exhibits superior accuracy and robustness compared to the traditional *** method initially generates an estimate of the predicted state and covariance matrix through the unscented transform(UT)and then recharacterizes the measurement information using a nonlinear regression method at the cost of ***,the state and covariance matrices of the filter are updated by employing the unscented transformation on the measurement ***,to mitigate the influence of non-line-of-sight(NLOS)errors positioning accuracy,this paper proposes a k-medoid clustering algorithm based on bisection k-means(Bikmeans).This algorithm preprocesses the UWB distance measurements to yield a more precise position *** results demonstrate that MCCUKF is robust to the uncertainty of UWB and realizes stable integration of INS and UWB systems.

关键词： Maximum correntropy criterion unscented Kalman filter inertial navigation system ultra-wideband bisecting kmeans clustering algorithm