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Ensemble successor representations for task generalization in offline-to-online reinforcement learning

Science China(Information Sciences) 2024年第7期67卷 240-255页

作者： Changhong WANG Xudong YU Chenjia BAI Qiaosheng ZHANG Zhen WANG Space Control and Inertial Technology research center Harbin Institute of Technology Shanghai Artificial Intelligence Laboratory Shenzhen research Institute of Northwestern Polytechnical University School of Cybersecurity Northwestern Polytechnical University

In reinforcement learning(RL), training a policy from scratch with online experiences can be inefficient because of the difficulties in exploration. Recently, offline RL provides a promising solution by giving an initialized offline policy, which can be refined through online interactions. However, existing approaches primarily perform offline and online learning in the same task, without considering the task generalization problem in offline-to-online adaptation. In real-world applications, it is common that we only have an offline dataset from a specific task while aiming for fast online-adaptation for several tasks. To address this problem, our work builds upon the investigation of successor representations for task generalization in online RL and extends the framework to incorporate offline-to-online learning. We demonstrate that the conventional paradigm using successor features cannot effectively utilize offline data and improve the performance for the new task by online fine-tuning. To mitigate this, we introduce a novel methodology that leverages offline data to acquire an ensemble of successor representations and subsequently constructs ensemble Q functions. This approach enables robust representation learning from datasets with different coverage and facilitates fast adaption of Q functions towards new tasks during the online fine-tuning *** empirical evaluations provide compelling evidence showcasing the superior performance of our method in generalizing to diverse or even unseen tasks.

关键词： offline reinforcement learning online fine-tuning task generalization successor representations ensembles

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LD-pumped acousto-optic 2-switched Pr:YLF pulsed laser at 604 nm

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Chinese Optics Letters 2024年第8期22卷 77-81页

作者： Wei Yuan Canlin Jiang Huiying Xu Zhiping Cai School of Electronic Science and Engineering Xiamen UniversityXiamen 361005China center for Modern Educational Technology Guizhou Normal UniversityGuiyang 550001China Fujian Key Laboratory of Ultrafast Laser Technology and applications Xiamen UniversityXiamen 361005China

We demonstrated an actively acousto-optic Q-switched pulsed laser based on Pr:YLF at 604 nm.A 604 nm continuous-wave(CW)laser with a maximum output power of 3.84 W was achieved for the first time,to the best of our *** Q-switched laser with a maximum average output power of 0.384 W,a narrowest pulse duration of 44.5 ns,a maximum single pulse energy of~64.1μJ,and a maximum peak power of~1.44 kW was obtained at a repetition rate of 6 *** far as we know,this was the first report of such a narrow pulse duration,high-power,and high-energy Q-switched pulsed laser at604 *** beam quality factors M_x~2and M_y~2were measured to be 2.87 and 2.40,*** results show that acousto-optic Q-switching is a promising method for obtaining pulsed lasers.

关键词： 604 nm acousto-optics Q-switching pulsed laser Pr:YLF crystal

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Nonvolatile and reconfigurable two-terminal electro-optic duplex memristor based on Ⅲ-nitride semiconductors

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Light(Science & applications) 2024年第4期13卷 706-716页

作者： Zhiwei Xie Ke Jiang Shanli Zhang Jianwei Ben Mingrui Liu Shunpeng Lv Yang Chen Yuping Jia Xiaojuan Sun Dabing Li State Key Laboratory of Luminescence and applications Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesDongnanhu Road No.3888Changchun 130033China center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesYuquan Road No.19100049 BeijingChina

With the fast development of artificial intelligence(AI),Internet of things(IOT),etc,there is an urgent need for the technology that can efficiently recognize,store and process a staggering amount of *** AlScN material has unique advantages including immense remnant polarization,superior temperature stability and good latticematch to other III-nitrides,making it easy to integrate with the existing advanced III-nitrides material and device ***,due to the large band-gap,strong coercive field,and low photo-generated carrier generation and separation efficiency,it is difficult for AlScN itself to accumulate enough photo-generated carriers at the surface/interface to induce polarization inversion,limiting its application in in-memory sensing and *** this work,an electro-optic duplex memristor on a GaN/AlScN hetero-structure based Schottky diode has been *** twoterminal memristor shows good electrical and opto-electrical nonvolatility and *** both electrical and opto-electrical modes,the current on/off ratio can reach the magnitude of 104,and the resistance states can be effectively reset,written and long-termly *** on this device,the“IMP”truth table and the logic“False”can be successfully reproduced,indicating the huge potential of the device in the field of in-memory sensing and computing.

关键词： polarization duplex limiting

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A multi-mechanistic approach to the oil recovery study of a family of amphiphilic polysaccharides

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Petroleum research 2024年第2期9卷 238-249页

作者： Funsho Afolabi Syed MMahmood Lunech Mario Nur Asyraf Md Akhir Bennett Tackie-Otoo Hamid Sharifigaliuk center of research in Enhanced Oil Recovery Universiti Teknologi PETRONASSeri IskandarMalaysia center for Subsurface Imaging Universiti Teknologi PETRONASSeri IskandarMalaysia research Institute of Petroleum Industry(RIPI) TehranIran

Chemical enhanced oil recovery(cEOR)remains one of the most potent tertiary recovery ***,it is expensive and rarely environmentally ***-based amphiphilic polymers have been suggested as an alternative to eradicating the challenges of conventional cEOR because of cost-effectiveness,and ***,few in-depth studies exist in the literature to investigate the prospects of these materials.A new family of amphiphilic polysaccharides was synthesized by hydrophobic modification of cellulose sulphate,and the EOR functionalities were *** novel biopolymers exhibited the ability to alter rock wetting *** terms of recovery,one of the variants of the synthesized bio amphiphilic polymer(D-I)was able to reduce residual oil saturation to 12%at harsh conditions of 60,000 ppm salinity at 75℃.Micromodel visual analysis revealed that the performance of the novel materials was due to the combination of mobility control,IFT lowering and emulsification,wettability alteration,and *** a performance commensurate to that of a commercial hydrophobically modified polymer,it can be said that the novel amphiphilic polysaccharides can stand as a viable cEOR agent for oilfield applications.

关键词： Bio-based polymers Amphiphilic polysaccharides EOR Cellulose sulphate Environmental sustainability

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The first chiral cerium halide towards circularly-polarized luminescence in the UV region

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Science China Chemistry 2024年第6期67卷 1961-1968页

作者： Xinyi Niu Zhichao Zeng Zhaoyu Wang Haolin Lu Bing Sun Hao-Li Zhang Yongsheng Chen Yaping Du Guankui Long Tianjin Key Lab for Rare Earth Materials and applications Renewable Energy Conversion and Storage CenterSmart Sensing Interdisciplinary Science CenterSchool of Materials Science and EngineeringNational Institute for Advanced MaterialsNankai UniversityTianjin300350China Tianjin Key Lab for Rare Earth Materials and applications Center for Rare Earth and Inorganic Functional MaterialsHaihe Laboratory of Sustainable Chemical TransformationsSmart Sensing Interdisciplinary Science CenterSchool of Materials Science and EngineeringNational Institute for Advanced MaterialsNankai UniversityTianjin300350China State Key Laboratory of Applied Organic Chemistry Key Laboratory of Special Function Materials and Structure Design(Ministry of Education)College of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou730000China The Centre of Nanoscale Science and Technology and State Key Laboratory of Elemento-Organic Chemistry Frontiers Science Center for New Organic MatterCollege of ChemistryNankai UniversityTianjin300071China

Chiral organic-inorganic hybrid metal halides(OIHMHs)have attracted broader scientific community recently in spin lightemitting diodes,and circularly polarized light-emitting ***,the emission peaks of the reported chiral OIHMHs mainly locate in the visible region,and chiral OIHMH with ultraviolet(UV)circularly polarized luminescence(CPL)has been rarely *** fill this gap,cerium,a unique rare-earth(RE)element with tunable luminescence from UV to the visible region owing to the 4 f-related electronic transition,was introduced to construct the first RE-based chiral OIHMHs,R/*** chirality is successfully transferred from the chiral organic cations to the inorganic cerium chloride framework in R/S-MCC,as confirmed by the single crystal structures,circular dichroism,and *** emission spectra of R/S-MCC are in the UV region,originating from the characteristic d-f transition of Ce^(3+),which making the Ce-based metal halides are ideal candidates towards CPL light sources in the UV ***,R-and S-MCC are the first RE-based OIHMHs,also the first chiral metalhalides with UV *** work opens a new avenue for the development of the chiral OIHMH family towards RE-based chiral *** RE-based chiral metal halides couple the unique and superior optical,electrical,magnetic,and spintronic properties of RE elements with chirality could accelerate the development of chiral optoelectronics and spintronics toward real applications.

关键词： chiral rare-earth halide ultraviolet circularly-polarized luminescence d-f transition rare-earth halide perovskite chiral perovskite

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Tunnel silicon nitride manipulated reconfigurable bi-mode nociceptor analog

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Photonics research 2024年第8期12卷 1820-1827页

作者： CHENGDONG YANG YILONG LIU LINLIN SU XINWEI LI LIHUA XU QIMEI CHENG Jiangsu Province Engineering research center of Integrated Circuit Reliability Technology and Testing System Wuxi UniversityWuxi 214105China

Neuromorphic applications have shown great promise not only for efficient parallel computing mode to hold certain computational tasks,such as perception and recognition,but also as key biomimetic elements for th intelligent sensory system of next-generation ***,achieving such a biomimetic nociceptor tha can adaptively switch operation mode with a stimulation threshold remains a *** rational design of material properties and device structures,we realized an easily-fabricated,low-energy,and reconfigurable no *** is capable of threshold-triggered adaptive bi-mode jump that resembles the biological alarm system With a tunnel silicon nitride(Si_(3)N_(4))we mimicked the intensity-and rehearsal-triggered jump by means of th tunneling mode transition of Si_(3)N_(4)*** threshold signals the device can also express some common synaptic functions with an extremely low energy density of 33.5 f J∕μm^(2).In addition,through the modulation o Si_(3)N_(4)thickness it is relatively easy to fabricate the device with differing pain *** nociceptor analog based on a tunneling layer provides an opportunity for the analog pain alarm system and opens up a new path toward threshold-related novel applications.

关键词： Tunnel tunneling rational

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SnIP-type atomic-scale inorganic double-helix semiconductors: Synthesis, properties, and applications

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Nano research 2024年第3期17卷 2111-2128页

作者： Mudussar Ali Bowen Zhang Muhammad Khurram Qingfeng Yan Engineering research center of Advanced Rare Earth Materials(Ministry of Education) Department of ChemistryTsinghua UniversityBeijing 100084China

Flexible inorganic double helical semiconductors similar to DNA have fueled the demand for efficient materials with innovative structures and excellent *** recent discovery of tin phosphide iodide(SnIP),the first carbon-free double helical semiconductor at an atomic level,has opened new avenues of research for semiconducting devices such as thermoelectric and sensor devices,solar cells,and *** has drawn significant academic attention due to its high structural flexibility,band gap in the visible spectrum range,and non-toxic ***,the recent progress in developing SnIP,including its prestigious structure,versatile and intriguing properties,and synthesis,is *** analogues of SnIP and SnIP-based hybrid materials and their applications in photocatalysis are also ***,the review concludes with a critical summary and future aspects of this new inorganic semiconductor.

关键词： tin phosphide iodide(SnIP) inorganic semiconductor inorganic double helix SnIP-based hybrids photocatalysis flexible material

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Ultra-robust informational metasurfaces based on spatial coherence structures engineering

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Light(Science & applications) 2024年第7期13卷 1310-1319页

作者： Leixin Liu Wenwei Liu Fei Wang Xiaofeng Peng Duk-Yong Choi Hua Cheng Yangjian Cai Shuqi Chen Shandong Provincial Engineering and Technical center of Light Manipulations Collaborative Innovation Center of Light Manipulation and ApplicationsShandong Provincial Key Laboratory of Optics and Photonic DeviceSchool of Physics and ElectronicsShandong Normal UniversityJinan 250014China. The Key Laboratory of Weak Light Nonlinear Photonics Ministry of EducationSchool of PhysicsSchool of Materials Science and EngineeringSmart Sensing Interdisciplinary Science CenterNankai UniversityTianjin 300071China. School of Physical Science and Technology Soochow UniversitySuzhou 215006China. Laser Physics Centre Research School of PhysicsAustralian National UniversityCanberraACT 2601Australia. The Collaborative Innovation center of Extreme Optics Shanxi UniversityTaiyuanShanxi 030006China

Optical information transmission is vital in modern optics and photonics due to its concurrent and multi-dimensional nature,leading to tremendous applications such as optical microscopy,holography,and optical *** optical information transmission technologies suffer from bulky optical setup and information loss/crosstalk when meeting scatterers or obstacles in the light ***,we theoretically propose and experimentally realize the simultaneous manipulation of the coherence lengths and coherence structures of the light beams with the disordered *** ultra-robust optical information transmission and self-reconstruction can be realized by the generated partially coherent beam with modulated coherence structure even 93%of light is recklessly obstructed during light transmission,which brings new light to robust optical information transmission with a single *** method provides a generic principle for the generalized coherence manipulation on the photonic platform and displays a variety of functionalities advancing capabilities in optical information transmission such as meta-holography and imaging in disordered and perturbative media.

关键词： optics coherent holography

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Merger estimates for a disformal Kerr black hole in quadratic degenerate higher-order scalar-tensor theories

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Chinese Physics C 2024年第5期48卷 284-292页

作者：蒋洪鑫杜欣怡潘启沅陈松柏荆继良 Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education Synergetic Innovation Center for Quantum Effects and Applicationsand Department of PhysicsHunan Normal UniversityChangsha 410081China Institute of Interdisciplinary Studies Hunan Normal UniversityChangsha 410081China center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou 225009China

We investigate the main features of a disformal Kerr black hole merger in quadratic degenerate higher-order scalar-tensor *** the ringdown stage of the black hole merger,for the prograde orbit,the real part of the quasinormal modes decreases with an increase in the disformal parameter,and the imaginary part also decreases,except in the Kerr case for a large spin ***,for the retrograde orbit,the real part increases with an increase in the disformal parameter,and the imaginary part always decreases with *** the approximate final spin,regardless of an equal spin,unequal spin,or generic spin configuration merger,the final black hole spin always increases with an increase in the disformal *** results show that the disformal parameter in the disformal Kerr solution and the MOG parameter in the Kerr-MOG case have obviously different effects on the black hole merger,which suggests the differences between these two spacetime structures.

关键词： black hole merger quasinormal modes final black hole spin disformal Kerr black hole quadratic degenerate higher-order scalar-tensor(DHOST)theory

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Gate-tunable Berry curvature in van der Waals itinerant ferromagnetic Cr_(7)Te_(8)

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InfoMat 2024年第3期6卷 108-116页

作者： Kui Meng Zeya Li Zhansheng Gao Xiangyu Bi Peng Chen Feng Qin Caiyu Qiu Lingyun Xu Junwei Huang Jinxiong Wu Feng Luo Hongtao Yuan National Laboratory of Solid State Microstructures Collaborative Innovation Center of Advanced MicrostructuresCollege of Engineering and Applied SciencesJiangsu Key Laboratory of Artificial Functional MaterialsNanjing UniversityNanjingthe People's Republic of China center for the Physics of Low-Dimensional Materials Henan Joint International Research Laboratory of New Energy Materials and DevicesSchool of Physics and ElectronicsHenan UniversityKaifengthe People's Republic of China Tianjin Key Lab for Rare Earth Materials and applications Center for Rare Earth and Inorganic Functional MaterialsSmart Sensor Interdisciplinary Science CenterSchool of Materials Science and EngineeringNankai UniversityTianjinthe People's Republic of China

The anomalous Hall effect(AHE)that associated with the Berry curvature of occupied electronic states in momentum-space is one of the intriguing aspects in condensed matter physics,and provides an alternative for potential applications in topological *** experiments reported the tunable Berry curvature and the resulting magnetization switching process in the AHE based on strain engineering or chemical ***,the AHE modulation by these strategies are usually irreversible,making it difficult to realize switchable control of the AHE and the resultant spintronic ***,we demonstrated the switchable control of the Berry-curvature-related AHE by electrical gating in itinerant ferromagnetic Cr_(7)Te_(8)with excellent ambient *** gate-tunable sign reversal of the AHE can be attributed to the redistribution of the Berry curvature in the band structure of Cr_(7)Te_(8)due to the intercalation-induced change in the Fermi *** work facilitates the applications of magnetic switchable devices based on gate-tunable Berry curvature.

关键词： anomalous Hall effect Berry curvature van der Waals itinerant ferromagnetism

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