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A passive wireless surface acoustic wave(SAW)sensor system for detecting warfare agents based on fluoroalcohol polysiloxane film

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Microsystems & Nanoengineering 2024年第1期10卷 67-78页

作者： Yong Pan Cancan Yan Xu Gao Junchao Yang Tengxiao Guo Lin zhang Wen Wang State Key Laboratory of NBC Protection for Civil Beijing 102205China Institute of Acoustics Chinese Academy of SciencesBeijing 100190China The School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China

Long-term monitoring of environmental warfare agengts is a challenge for chemical gas *** address this issue,we developed a 433 MHz passive wireless surface acoustic wave(WSAW)gas sensor for dimethyl methylphosphonate(DMMP)*** WSAW gas sensor includes a YZ lithium niobate(LiNbO_(3))substrate with metallic interdigital transducers(IDTs)etched on it,and an antenna was placed near the IDT.A DMMP-sensitive viscoelastic polymer fluoroalcoholpolysiloxane(SXFA)film was prepared on a LiNbO_(3) substrate,and mode modeling coupling was used to optimize the design *** sensor can function properly in an environments between−30℃ and 100℃ with humidity less than 60%*** the wireless transmission distance was within the range of 0-90 cm,the sensor noise increased with distance,and the stability was less than 32°/*** optimizing the film thickness of SXFA,a relationship was observed between sensor sensitivity and film *** the film thickness of SXFA reached 450 nm,the optimal value was *** a distance of 20 cm between the transmitting and receiving antennas,DMMP was detected at different concentrations with the developed WSAW gas *** lower detection limit of DMMP was 0.48 mg/m^(3),the sensitivity of the sensor was 4.63°/(mg/m^(3)),and repeatable performance of the sensor was confirmed.

关键词： film alcohol passive

Ablative behavior and mechanism of SiC_(f) /SiBCZr composites prepared by PIP process

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Journal of Advanced Ceramics 2024年第1期13卷 124-134页

作者： Mingwei Chen Yuliang Zhao Haipeng Qiu Shijian Liu Weijie Xie Yi Chen Qiyue zhang AVIC Manufacturing Technology Institute Beijing 100130China

SiC_(f)/SiBCZr composites were prepared by polymer precursor impregnation and pyrolysis process with near stoichiometric ratio SiC fiber preform as reinforcement phase and SiBCZr multiphase ceramic precursor as impregnating *** results highlighted that the SiC_(f)/SiBCZr composites exhibited excellent ablative properties after ablative tests at 1200℃/3600 s and 1400℃/3600 s,and the strength retention rates of the composites reached 90%and 85%,*** was mainly due to the liquid sealing effect of the ablative products represented by B2O_(3) and SiO_(2)∙B_(2)O_(3),which inhibited the ablative reaction by reducing the diffusion rate of the oxidation medium,and the solid pinning effect of the substances represented by SiO_(2),ZrO_(2),and ZrSiO_(4),which could play high viscosity and high strength characteristics to improve anti-erosion *** above-mentioned SiC_(f)/SiBCZr composites with corrosion resistance,oxidation resistance,and ablative resistance provided a solid material foundation and technical support for the development of reusable spacecraft hot-end components.

关键词： near stoichiometric ratio SiC fiber SiC_(f)/SiBCZr composite liquid sealing effect solid pinning effect

Improved direct current electrical properties of XLPE modified by graftable antioxidant and crosslinking coagent at a wide temperature range

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High Voltage 2024年第1期9卷 94-104页

作者： Xu Yang Hong Zhao Chengcheng zhang Chunyang Li Xindong Zhao Jiaming Yang Xuan Wang Key Laboratory of Engineering Dielectrics and Its Application Harbin University of Science and TechnologyHarbinChina

To enhance the DC electrical performance of cross-linked polyethylene(XLPE),the graftable antioxidant methacrylic acid 2-hydroxy-3-(4-anilinoanilino)propyl ester(GA),which contains carbonyl and amino groups,and the crosslinking coagent trimethylolpropane trimethacrylate(TMPTMA),which contains carbonyl groups,are individually or co-grafted onto *** slightly higher deep trap density introduced by higher grafting concentration of TMPTMA results in more significant suppression effect of conductance current and enhanced breakdown strength at a lower temperature,while the suppression effect for the conductance current at 90°C becomes weakened due to limited trap ***,the deeper energy level introduced by GA suppresses the conductance current and improves the electrical strength of XLPE at 90°C more *** co-grafting,the conductance current of XLPE in a wide range temperature can be significantly reduced,especially for the temperature dependence of conductance current,which is beneficial to suppress the field strength *** results of thermally stimulated current and molecular simulation show that the polar groups of two monomers introduce deep charge traps in *** co-grafting system ensures the rationality of the crosslinking reaction kinetics and does not affect the cable manufacturing.

关键词： crosslinking electrical grafting

科学态度与责任素养的落实:基本路向与有效策略

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教育学术月刊 2024年第1期 100-105页

作者：张恩德于珍徐平川韩山师范学院物理与电子工程学院广东潮州521041 嘉应学院教育科学学院广东梅州514005 西华师范大学物理与天文学院四川南充637009

科学态度与责任素养是我国中学物理新课改的重要亮点。科学态度与责任素养在宏观层面的落实路向、在中微观层面的落实策略,有利于一线教师在科学态度与责任素养落实过程的课程转换与灵性生成。科学态度与责任素养落实的基本路向涵盖课... 详细信息

科学态度与责任素养是我国中学物理新课改的重要亮点。科学态度与责任素养在宏观层面的落实路向、在中微观层面的落实策略,有利于一线教师在科学态度与责任素养落实过程的课程转换与灵性生成。科学态度与责任素养落实的基本路向涵盖课程路向、活动路向和文化路向。科学态度与责任素养落实的有效策略包含素养对标策略、素养萃取策略、素养渗透策略、素养生成策略等。

关键词：科学态度与责任科学本质核心素养

A survey on model-based reinforcement learning

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Science China(Information Sciences) 2024年第2期67卷 59-84页

作者： Fan-Ming LUO Tian XU Hang LAI Xiong-Hui CHEN Weinan zhang Yang YU National Key Laboratory for Novel Software Technology Nanjing University Polixir. ai Department of Computer Science and Engineering Shanghai Jiao Tong University

Reinforcement learning(RL) interacts with the environment to solve sequential decision-making problems via a trial-and-error approach. Errors are always undesirable in real-world applications, even though RL excels at playing complex video games that permit several trial-and-error attempts. To improve sample efficiency and thus reduce errors, model-based reinforcement learning(MBRL) is believed to be a promising direction, as it constructs environment models in which trial-and-errors can occur without incurring actual costs. In this survey, we investigate MBRL with a particular focus on the recent advancements in deep RL. There is a generalization error between the learned model of a non-tabular environment and the actual environment. Consequently, it is crucial to analyze the disparity between policy training in the environment model and that in the actual environment, guiding algorithm design for improved model learning, model utilization, and policy training. In addition, we discuss the recent developments of model-based techniques in other forms of RL, such as offline RL, goal-conditioned RL, multi-agent RL, and meta-RL. Furthermore,we discuss the applicability and benefits of MBRL for real-world tasks. Finally, this survey concludes with a discussion of the promising future development prospects for MBRL. We believe that MBRL has great unrealized potential and benefits in real-world applications, and we hope this survey will encourage additional research on MBRL.

关键词： reinforcement learning model-based reinforcement learning planning model learning model learning with reduced error model usage

Efficient nitrate electroreduction over Mn-doped Cu catalyst via regulating N-containing intermediates adsorption configuration

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Science China Chemistry 2024年第6期67卷 1969-1975页

作者： Limin Wu Shunhan Jia Libing zhang Ruhan Wang Jiaqi Feng Xiaofu Sun Buxing Han Beijing National Laboratory for Molecular Sciences CAS Laboratory of Colloid and Interface and ThermodynamicsCAS Research/Education Center for Excellence in Molecular SciencesCenter for Carbon Neutral ChemistryInstitute of ChemistryChinese Academy of SciencesBeijing100190China School of Chemical Sciences University of Chinese Academy of SciencesBeijing100049China College of Chemical Engineering and Environment China University of PetroleumBeijing102249China Shanghai Key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular EngineeringEast China Normal UniversityShanghai200062China

The electrochemical reduction of NO_(3)^(-)to NH_(3)holds promise for economic and environmental benefits,presenting an energyefficient alternative to the traditional Haber-Bosch ***,challenges exist due to its sluggish kinetics,multiple intermediates,and various reaction *** this study,Mn-doped-Cu catalyst was synthesized and employed for electrochemical NO_(3)^(-)-to-NH_(3)*** doping of Mn into Cu resulted in exceptional performance,achieving a FE of 95.8%and an NH_(3)yield rate of 0.91 mol g^(-1)h^(-1)at-0.6 V in a neutral electrolyte at low NO_(3)^(-)*** experimental studies and theoretical calculations revealed that the Mn dopant enhanced the kinetic rate of NO_(2)~--to-NH_(3)and induced a distinct configuration of**** alteration decreased the energy barrier of*NO-to-*NOH,consequently promoting the conversion of NO_(3)^(-)-to-NH_(3).

关键词： nitrate reduction electrocatalysis ammonia synthesis N-intermediate green chemistry

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Tailoring chaotic motion of microcavity photons in ray and wave dynamics by tuning the curvature of space

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 107-112页

作者： Wei Lin Yechun Ding Yongsheng Wang Peng Li Yanpeng zhang Feng Yun Feng Li Key Laboratory for Physical Electronics and Devices of the Ministry of Education Shaanxi Key Lab of Information Photonic TechniqueSchool of Electronic Science and EngineeringFaculty of Electronic and Information EngineeringXi’an Jiaotong UniversityXi’an 710049China Department of Electrical and Photonics Engineering Technical University of DenmarkKgs.Lyngby 2800Denmark Center for Regenerative and Reconstructive Medicine Med-X InstituteThe First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061China Solid-State Lighting Engineering Research Center Xi’an Jiaotong UniversityXi’an 710049China

Microcavity photon dynamics in curved space is an emerging interesting area at the crossing point of nanophotonics,chaotic science,and non-Euclidean *** report the sharp difference between the regular and chaotic motions of cavity photons subjected to the varying space *** the island modes of regular motion rise in the phase diagram in the curved space,the chaotic modes show special mechanisms to adapt to the space curvature,including the fast diffusion of ray dynamics,and the localization and hybridization of the Husimi wavepackets among different periodic *** observations are unique effects enabled by the combination of the chaotic trajectory,the wave nature of light,and the non-Euclidean orbital motion,and therefore make the system a versatile optical simulator for chaotic science under quantum mechanics in curved space-time.

关键词： microcavity chaotic motion curved space

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改性聚丙烯酰胺降低油水界面张力行为的分子动力学模拟

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中国石油大学学报（自然科学版） 2024年第3期48卷 215-220页

作者：燕友果郝羽键伊卓李雅婧张军李振中国石油大学(华东)材料科学与工程学院山东青岛266580 中国石油化工股份有限公司北京化工研究院北京100013

采用分子动力学模拟方法,从原子分子层次考察部分水解聚丙烯酰胺(HPAM)以及改性HPAM的界面活性。结果表明:HPAM降低油水界面张力能力极其有限,而引入疏水基团后的HPAM具有较好的降低界面张力效果;改性HPAM的疏水基团增强与油相的作用,... 详细信息

采用分子动力学模拟方法,从原子分子层次考察部分水解聚丙烯酰胺(HPAM)以及改性HPAM的界面活性。结果表明:HPAM降低油水界面张力能力极其有限,而引入疏水基团后的HPAM具有较好的降低界面张力效果;改性HPAM的疏水基团增强与油相的作用,并在界面处形成致密的聚合物膜,增加油水界面层厚度,隔离油水相接触,从而降低油水接触形成的界面张力;盐离子的存在增加油水界面张力,改性HPAM引入的磺酸基团具有较好的抗盐能力,可以降低界面处盐离子的聚集,从而减弱盐离子对界面张力的影响。

关键词：改性聚丙烯酰胺界面张力分子动力学模拟

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LDL-C rebound after long-term evolocumab treatment and intravascular imaging evidence in a familial hypercholesterolemia patient with early-onset myocardial infarction

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Chronic Diseases and Translational Medicine 2024年第1期10卷 69-74页

作者： Zhifan Li Shuang zhang zheng Yin Wenjia zhang Yonggang Sui Jianjun Li Kefei Dou Jie Qian Naqiong Wu Cardiometabolic Center National Center for Cardiovascular DiseasesFuwai HospitalChinese Academy of Medical Science and Peking Union Medical CollegeBeijingChina

Patients with familial hypercholesterolemia(FH)have elevated low-density lipoprotein cholesterol(LDL-C)levels and are at high risk of premature cardiovascular disease.1 Heterozygous FH(HeFH)is one of the commonest genetic disorders,and is more frequent among those with ischemic heart disease(IHD),atherosclerotic cardiovascular disease(ASCVD)and premature IHD.

关键词： cardiovascular familial elevated