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Dielectric response of ANb_(2)O_(6)(A = Zn, Co, Mn, Ni) columbite niobates: From microwave to terahertz

Journal of Advanced Ceramics 2024年第8期13卷 1189-1197页

作者： Weijia Luo Shun Wang Siyong Zheng Jining Li Menglong Wang Yongzheng Wen ingxia Li Ji Zhou State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Institute of Laser and optoelectronics School of Precision Instrument and Opto-Electronics EngineeringTianjin UniversityTianjin 300072China Shandong Inspur Artificial Intelligence Research Institute Co. Ltd.Jinan 250013China School of Microelectronics Tianjin UniversityTianjin 300072China

In the upcoming 6-generation(6G)revolution,the achievement of low power consumption has become a key objective in research concerning terahertz *** an important component of passive devices,there are very few low-loss dielectric ceramics in the terahertz *** elucidate the mechanism of loss and promote the application of microwave dielectric ceramics for future 6G technology(covering microwave and terahertz frequencies),the terahertz responses of ANb_(2)O_(6)(A=Zn,Co,Mn,and Ni)columbite niobates were *** influences of magnetic loss on the Qxf values in the microwave range with different transition metal ions in the A-site were reasonably ***,due to the weakened magnetic relaxation properties in the terahertz range,the samples all exhibited low loss and approximate transparency,especially for MnNb_(2)O_(6) and NiNb_(2)O_(6)(tano<0.01 and absorption coefficient<10 cm^(-1) below 1.2 THz),which subverted the definition of traditional low-loss microwave dielectric ***,based on Mie theory,we designed a prototypical broadband metamaterial reflector to validate the applicability of the ANb_(2)O_(6) system in the terahertz band,which is highly important for the development of terahertz ceramic-based passive devices.

关键词： columbite niobates terahertz response transition metal ions magnetic loss ceramic-based metamaterials

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A survey of decision making in adversarial games

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Science China(Information Sciences) 2024年第4期67卷 85-112页

作者： Xiuxian LI Min MENG Yiguang HONG Jie CHEN college of electronics and Information engineering Tongji University Shanghai Research Institute for Intelligent Autonomous Systems

In many practical applications, such as poker, chess, drug interdiction, cybersecurity, and national defense, players often have adversarial stances, i.e., the selfish actions of each player inevitably or intentionally inflict loss or wreak havoc on other players. Therefore, adversarial games are important in realworld applications. However, only special adversarial games, such as Bayesian games, are reviewed in the literature. In this respect, this study aims to provide a systematic survey of three main game models widely employed in adversarial games, i.e., zero-sum normal-form and extensive-form games, Stackelberg(security) games, and zero-sum differential games, from an array of perspectives, including basic knowledge of game models,(approximate) equilibrium concepts, problem classifications, research frontiers,(approximate) optimal strategy-seeking techniques, prevailing algorithms, and practical applications. Finally, promising future research directions are also discussed for relevant adversarial games.

关键词： adversarial games zero-sum games Stackelberg games differential games Nash equilibrium correlated equilibrium regret

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Towards Sustainable Grinding of Difficult-to-Cut Alloys-A Holistic Review and Trends

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Chinese Journal of Mechanical engineering 2024年第2期37卷 1-28页

作者： Ning Qian Jiajia Chen Aqib Mashood Khan Biao Zhao Yurong Chen Wenfeng Ding Yucan Fu Jiuhua Xu Jiangsu Key Laboratory of precision and Micro-Manufacturing Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China college of Mechanical and Electronic engineering Nanjing Forestry UniversityNanjing 210037China JITRI Institute of precision Manufacturing Nanjing 211805China

Grinding,a critical precision machining process for difficult-to-cut alloys,has undergone continual technological advancements to improve machining ***,the sustainability of this process is gaining heightened attention due to significant challenges associated with the substantial specific grinding energy and the extensive heat generated when working with difficult-to-cut alloys,renowned for their exceptional physical and mechanical *** response to these challenges,the widespread application of massive coolant in manufacturing industries to dissipate grinding heat has led to complex post-cleaning and disposal ***,in turn,has resulted in issues such as large energy consumption,a considerable carbon footprint,and concerns related to worker health and safety,which have become the main factors that restrict the development of grinding *** paper provides a holistic review of sustainability in grinding difficult-to-cut alloys,encompassing current trends and future *** examination extends to developing grinding technologies explicitly tailored for these alloys,comprehensively evaluating their sustainability ***,the exploration delves into innovative sustainable technologies,such as heat pipe/oscillating heat pipe grinding wheels,minimum quantity lubrication,cryogenic cooling,and *** groundbreaking technologies aim to reduce dependence on hazardous coolants,minimizing energy and resource consumption and carbon emissions associated with coolant-related or subsequent disposal *** essence of these technologies lies in their potential to revolutionize traditional grinding practices,presenting environmentally friendly ***,future development trends and research directions are put forward to pursue the current limitation of sustainable grinding for difficult-to-cut *** paper can guide future research and development efforts toward more environmentally friendly

关键词： Grinding Sustainability Cooling Energy consumption Carbon footprint Difficult-to-cut alloys

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Stability-enhanced RF signal transmission over long fiber-optic links

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Chinese Optics Letters 2024年第5期22卷 131-136页

作者：尹知谦郑满航张川博管世健周昕刘奕彤刚泽宇聂佳强张云山朱兴邦方涛陈向飞 engineering Research Center of precision Photonics Integration and System Application Ministry of Education&Key Laboratory of Intelligent Optical Sensing and ManipulationMinistry of Education&National Laboratory of Solid State Microstructures&College of Engineering and Applied Sciences&Institute of Optical Communication Engineering&Nanjing University-Tongding Joint Lab for Large-scale Photonic Integrated CircuitsNanjing UniversityNanjing 210023China college of electronics and Optical engineering and college of Flexible electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023China The 41st Research Institute of China electronics Technology Group Corp Qingdao 266000China

We propose a method for optimizing the phase stability of microwave signal transmission over long ***,the design of the photon link was modified to reduce the radio frequency(RF)signal’s baseline noise and increase ***,a low-noise driver circuit was developed for a two-section distributed feedback(DFB)laser designed using reconstruction equivalent chirp(REC)technology to create an ultra-stable laser,and its performance was characterized through linewidth *** results indicate that the DFB laser achieved narrower linewidth,improving system phase *** an injection current(30 mA)is applied to the reflection section of the two-section DFB laser,the laser linewidth will be narrower(1.38 MHz),further enhancing the system’s phase transmission *** a 1 Hz offset frequency,a residual phase noise of-88.65 dBc/Hz is *** short-term stability with an averaging time of 1 s is 1.60×10^(-14),and the long-term stability over a testing time of 60,000 s is 3.41×10^(-18).Even after incorporating temperature variations,the long-term stability reaches 8.37×10^(-18) at 22 h.

关键词： frequency dissemination two-section distributed feedback laser phase stability

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2D all-organic perovskites refine flexible electronics

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Science China Materials 2024年第7期67卷 2365-2366页

作者： Wei Zhou Bing Chen college of Electronic and Optical engineering and college of Flexible electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023China

Recent years have witnessed a paradigm shift with the advent of perovskites,a class of materials with a distinct CaTiO_(3)-type crystalline structure that show remarkable promise across a wide array of applications,including photovoltaics,photodetectors,lighting,lasers,and so *** them,the development of two-dimensional(2D)perovskites has garnered significant attention due to their tunable structures(mainly Dion-Jacobson and Ruddlesden-Popper structures)and enhanced stability in comparison with their 3D counterparts[1].Amidst the burgeoning research on perovskites,on the other side,all-organic perovskites stand out as a particularly intriguing subset[2].Unlike traditional perovskites that typically comprise all-inorganic(e.g.,CsPbBr_(3))or organic-inorganic hybrid components(e.g.,(PEA)_(2)PbI_(4)),all-organic perovskites are composed entirely of carbon-or nitrogen-based molecules.

关键词： perovskite inorganic entirely

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Design of improved error-rate sliding window decoder for SC-LDPC codes: reliable termination and channel value reuse

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optoelectronics Letters 2024年

作者： JIA Xishan LI Jining YAO Yuan WANG Yifan LIU Bo XU Degang School of precision instruments and opto-electronics engineering， Tianjin University Key Laboratory of optoelectronics Information Technology (Ministry of Education)， Tianjin University Institute of Modern Optics， college of Electronic Information and Optical engineering， Nankai University Tianjin Key Laboratory of optoelectronic Sensor and Sensing Network Technology

In this paper， an improved error-rate sliding window decoder is proposed for spatially coupled low-density parity-check (SC-LDPC) codes. For the conventional sliding window decoder， the message retention mechanism causes unreliable messages along the edges of belief propagation (BP) decoding in the current window to be kept for subsequent window decoding. To improve the reliability of the retained messages during the window transition， a reliable termination method is embedded， where the retained messages undergo more reliable parity checks. Additionally， decoding failure is unavoidable and even causes error propagation when the number of errors exceeds the error-correcting capability of the window. To mitigate this problem， a channel value reuse mechanism is designed， where the received channel values are utilized to reinitialize the window. Furthermore， considering the complexity and performance of decoding， a feasible sliding optimized-window decoding (SOWD) scheme is introduced. Finally， simulation results confirm the superior performance of the proposed SOWD scheme in both the waterfall and error floor regions. This work has great potential in the applications of wireless optical communication and fiber optic communication.

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Anomalous response to creep deformation from dislocation density during electrically assisted creep aging

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Rare Metals 2024年第10期43卷 5268-5283页

作者： Chang Zhou Li-Hua Zhan Chun-Hui Liu Ming-Hui Huang college of Mechanical and Electrical engineering Central South University Light Alloys Research Institute State Key Laboratory of Precision Manufacturing for Extreme Service PerformanceCentral South University

Adding numerous dislocations into metallic materials before the forming stage significantly enhances their deformability. However, this beneficial effect of dislocation defects may not have a simple monotonic relationship with increased dislocation density during electroplastic deformation. This is due to the complex interactions among the drifting electrons, dislocations and solute atoms. This study explores the effect of diverse initial dislocation densities on creep deformation during electrically aided creep aging of an aluminum–lithium alloy. Surprisingly, we discovered a threshold value for the dislocation density that affects electroplastic creep, i.e., an enhanced effect from dislocations weakens when exceeding this density threshold(an anomalous response to creep). Microstructural data also reveal that such an anomalous response originates mainly from differences in various dislocation density-tailored configurations, which can influence the dislocation motions and precipitation kinetics of the strengthening T1precipitates under the same action of pulsed currents. This study provides important insights into the dislocation density-mediated electroplastic creep of an aluminum–lithium alloy.

关键词： Al–Cu–Li alloy Creep aging Dislocation density Pulsed currents

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Maximizing Solar Potential Using the Differential Grey Wolf Algorithm for PV System Optimization

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Energy engineering 2024年第8期121卷 2129-2142页

作者： Ezhilmathi Nagarathinam Buvana Devaraju Karthiyayini Jayamoorthy Padmavathi Radhakrishnan Santhana Lakshmi ChandraMohan Vijayakumar Perumal Karthikeyan Balakrishnan Department of Electrical and electronics engineering Pandian Saraswathiyadav Engineering CollegeSivagangaiTamil Nadu630561India Department of Electrical and electronics engineering Sri Balaji Chockalingam Engineering CollegeArniTamil Nadu632317India Department of Information Science and engineering New Horizon College of EngineeringBangalore560103India Department of Electrical and electronics engineering Rajalakshmi Engineering CollegeChennaiTamil Nadu602105India Department of Electrical and electronics engineering Sona College of TechnologySalemTamil Nadu636005India School of electronics engineering Vellore Institute of TechnologyChennaiTamil Nadu600127India Department of Electrical and electronics engineering Sri Krishna College of Engineering and TechnologyCoimbatoreTamil Nadu641008India

Maximum Power Point Tracking(MPPT)is crucial for maximizing the energy output of photovoltaic(PV)systems by continuously adjusting the operating point of the panels to track the point of maximum power production under changing environmental *** work proposes the design of an MPPT system for solar PV installations using the Differential Grey Wolf Optimizer(DGWO).It dynamically adjusts the parameters of the MPPT controller,specifically the duty cycle of the SEPIC converter,to efficiently track the Maximum Power Point(MPP).The proposed system aims to enhance the energy harvesting capability of solar PV systems by optimizing their performance under varying solar irradiance,temperature and shading *** results demonstrate the effectiveness of the DGWO-based MPPT system in maximizing the power output of solar PV installations compared to conventional MPPT *** research contributes to the development of advanced MPPT techniques for improving the efficiency and reliability of solar energy systems.

关键词： DGWO SEPIC converter MPPT PV module

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Fabrication of Superhydrophobic–Hydrophilic Patterned Cu@Ag Composite SERS Substrate via Femtosecond Laser

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Nanomanufacturing and Metrology 2024年第1期7卷 1-14页

作者： Yuheng Zhang Zongwei Xu Kun Zhang Ying Song Bing Dong Jianshi Wang Mengzhi Yan Qingqing Sun State Key Laboratory of precision Measuring Technology and instruments Laboratory of Micro/Nano Manufacturing TechnologyTianjin UniversityTianjin 300072China Shandong Agricultural Equipment Intelligent engineering Laboratory Shandong Provincial Key Laboratory of Horticultural Machinery and EquipmentCollege of Mechanical and Electronic EngineeringShandong Agricultural UniversityTai’an 827101China

Ultralow concentration molecular detection is critical in various fields,e.g.,food safety,environmental monitoring,and dis-ease *** sensitive surface-enhanced Raman scattering(SERS)based on ultra-wettable surfaces has attracted attention due to its unique ability to detect trace ***,the complexity and cost associated with the preparation of traditional SERS substrates restrict their practical ***,an efficient SERS substrate preparation with high sensitivity,a simplified process,and controllable cost is *** this study,a superhydrophobic–hydrophilic patterned Cu@Ag composite SERS substrate was fabricated using femtosecond laser processing technology combined with silver plating and surface modification *** inducing periodic stripe structures through femtosecond laser processing,the developed substrate achieves uniform distribution *** the surface wettability difference,the object to be measured can be confined in the hydrophilic region and the edge of the hydrophilic region,where the analyte is enriched by the coffee ring effect,can be quickly located by surface morphology difference of micro-nanostructures;thus,greatly improving detec-tion *** fabricated SERS substrate can detect Rhodamine 6G(R6G)at an extraordinarily low concentration of 10^(−15)mol/L,corresponding to an enhancement factor of 1.53×10^(8).This substrate has an ultralow detection limit,incurs low processing costs and is simple to prepare;thus,the substrate has significant application potential in the trace analysis field.

关键词： Femtosecond laser Surface-enhanced Raman scattering Coffee ring effect Superhydrophobic–hydrophilic surface

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High-efficiency and flexible photonic microwave harmonic down-converter based on self-oscillation optical frequency combs

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Chinese Optics Letters 2024年第6期22卷 196-204页

作者： Xin Zhang Tao Pu Huatao Zhu Yunshan Zhang Gengze Wu Jin Li Jilin Zheng college of Information and Communications National University of Defense TechnologyWuhan 430010China college of Communications engineering Army Engineering University of PLANanjing 210007China college of Electronic and Optical engineering&college of Flexible electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023China

Photonic microwave harmonic down-converters (PMHDCs) based on self-oscillation optical frequency combs (OFCs) are interesting because of their broad bandwidth compared with plain optoelectronic oscillators. In this paper, a high-efficiency and flexible PMHDC is proposed and demonstrated. The properties of the OFC, such as the carrier-to-noise ratio (CNR),bandwidth and free spectral range (FSR), and the influence of optical injection, are investigated. The broadband OFC provides a frequency tunable and high-quality local oscillation (LO), which guarantees flexible down-conversion for the radio frequency (RF) signal. The sideband selective amplification (SSA) effect not only improves the conversion efficiency but also promotes single-sideband modulation. The conversion range can reach 100 GHz. The 12–40 GHz RF signal can be downconverted to intermediate frequency (IF) signals with a high conversion efficiency of 14.9 dB. The fixed 40-GHz RF signal is flexibly down-converted to an IF signal with the frequency from 55.4 to 2129.4 MHz. The phase noise of an IF signal at a frequency offset of 10 kHz is the same as that of the input RF signal. The PMHDC shows great performance and will find applications in radio-over-fiber (RoF) networks, electronic warfare receivers, avionics, and wireless communication systems.

关键词： frequency down-conversion optical frequency comb optical injection optoelectronic oscillation

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