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4th International Symposium on High Power Laser Science and Engineering, HPLSE 2021

作者： Huang, Jingguo Li, Yang Huang, Zhiming Gao, Yanqing Ezhov, Dmitry Lubenko, Dmitry Andreev, Yury State Key Laboratory of Infrared Physics Shanghai Institute of Technical Physics 500 Yu Tian Road Shanghai200083 China Key Laboratory of Space Active Opto-Electronics Technology Shanghai Institute of Technical Physics 500 Yu Tian Road Shanghai200083 China Tomsk State University 36 Lenin Ave. Tomsk634050 Russia Institute of High Current Electronics SB RAS 2/3 Akademichesky Ave. Tomsk634055 Russia Institute of Monitoring of Climatic and Ecological System SB RAS 10/3 Akademichesky Ave. Tomsk634055 Russia

ISBN: (数字)9781510645431

ISBN: (纸本)9781510645424

Optical properties of a Li2B4O7 (LB4) crystal are determined in the spectral range 0.2-1.6 THz. Dispersion of the refractive index components for o- and e-wave are approximated in the form of Sellmeier equations. They are subsequently used to determine the possible interaction types and to calculate the phase-matching angles to get THz waves by difference frequency generation. The damage threshold is determined as well as the coherence length for all possible types of three wave interactions under the pump by fs Ti: Sapphire laser pulses at 950 nm. The efficiency of the processes is estimated. Using trains of hundreds of pulses at 950 nm it was found to be 1.32 times of that for β-BBO crystal laser pump. © 2021 SPIE.

关键词： Phase matching

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Joint Observations of Plasmapause Surface Waves and Giant Undulations in the Electron Aurora

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Journal of Geophysical Research: Space Physics 2025年第6期130卷

作者： Xin-Yu Ai Jie Ren Qiu-Gang Zong Yi-Xin Hao Zi-Jian Feng Ting-Yan Xiang Institute of Space Physics and Applied Technology Peking University Beijing China Key Laboratory of Intraplate Volcanoes and Earthquakes China University of Geosciences (Beijing) Beijing China State Key Laboratory of Lunar and Planetary Science Macau University of Science and Technology Macau China Max Planck Institute for Solar System Research Göttingen Germany

After the onset of an intense storm-time substorm (the minimum AL ∼ ${\sim} $ −2,400 nT) on 8 September 2017, both Van Allen Probes and ground stations observed large-amplitude plasmasphere surface waves (PSWs) in the duskside, which lasted for more than 3 hr. Van Allen Probe B observations show that PSWs caused spatial and temporal modulations of sub-keV electrons with bidirectional pitch-angle distributions and higher-frequency plasma waves outside the plasmapause at the L-shells of 3.5–5.5. These kinetic-scale waves include kinetic Alfvén waves (KAWs) with frequencies below 10 Hz, time domain structures with frequencies from tens to hundreds of Hz, and electrostatic electron cyclotron harmonic waves (ECHs) with frequencies of tens of kHz. The bidirectional pitch angles and flux enhancement of sub-keV electrons indicate that they originate from the ionospheric outflow and are susceptible to pitch-angle scattering by kinetic-scale plasma waves. Following Probe B with a time delay of about 2 hr, Probe A observed PSW-associated ULF waves inside the plasmasphere at L-shells of 5–6, which can cause the drift-bounce resonance of cold ( < ${< } $ 50 eV) electrons. Corresponding to the duration and location of PSWs, DMSP-F17 observed intense sub-keV electron precipitation and weak ion precipitation, which coincides with the observations of giant undulations (GUs) in the electron aurora. These space-ground joint observations provide new sights into understanding the complicated middle processes between magnetospheric PSWs and ionospheric GUs. Sub-keV ionospheric outflows (both electrons and protons) and different kinetic-scale waves outside the plasmapause were modulated by plasmasphere surface waves (PSWs) ULF waves, decayed PSWs away from the plasmapause, only affected the low-energy electrons ( < ${< } $ 50 eV) in the plasmasphere Giant undulations in the electron aurora observed by Defense Meteorological Satellite Program are closely associated with sub-keV electrons a

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Design and analysis of a variable-span and cambered span morphing wing for UAV

Design and analysis of a variable-span and cambered span mor...

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2019 IEEE International Conference on robotics and Biomimetics, ROBIO 2019

作者： Yang, Guang Guo, Hongwei Liu, Rongqiang Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin Heilongjiang Province China

ISBN: (纸本)9781728163215

The variable-span and cambered span morphing wing for unmanned aerial vehicle (UAV) can greatly improve its flight efficiency. In this work, a new extendable and bendable morphing wing with double driving is designed. The morphing skeleton of wing is composed of the basic unit module which is seven-bar mechanism in series. The rubber-filled corrugated sandwich corrugated skin is designed according to the requirement of morphing skeleton. The kinematics model of morphing skeleton that is composed of three modules in series is established, then the kinematics analysis of morphing skeleton is carried out, at last the expressions of the deformed position and driving angle are obtained. In the case of the same wing span, the influence of different rod length ratio on the maximum extension length of the morphing wing is analyzed, and the influence of different driving speed on the maximum bending angle under the same rod length ratio is compared and analyzed. © 2019 IEEE.

关键词： Wings

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Wetland classification based on depth-adaptive convolutional neural networks using leaf-off SAR imagery

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Science of the Total Environment 2024年 957卷 177768页

作者： Zhang, Xin Du, Ling Tan, Shen McCarty, Gregory W. Zou, Zhenhua Department of Computing and Mathematics Manchester Metropolitan University ManchesterM1 5GD United Kingdom Department of Environmental Science & Technology University of Maryland College ParkMD20742 United States Hydrology and Remote Sensing Laboratory USDA-ARS BeltsvilleMD20705 United States State Key Laboratory of Efficient Production of Forest Resources Beijing Forestry University Beijing100083 China Sino-French Institute for Earth System Science College of Urban and Environmental Sciences Peking University Beijing100871 China Department of Geographical Sciences University of Maryland College ParkMD20742 United States

The recent development of deep learning (DL) techniques has created opportunities for classifying wetlands from remote sensing data (mainly optical data). However, the methods for accurately and efficiently classifying large-scale wetlands using DL and radar data that can be more effective than optical data still needs evaluation. In this study, we developed an end-to-end depth-adaptive convolutional neural network (CNN) for mapping wetlands using leaf-off time-series Sentinel-1 Synthetic Aperture Radar (SAR) imagery along with ancillary data. We examined the inclusion of multi-land cover proximity information and a CNN-based self-supervised SAR denoising procedure for enhancing wetland classification accuracy. The depth-adaptive CNN based on U-Net architecture was designed to classify wetland classes (emergent wetland, scrub-shrub wetland, forested wetland, and open water) in Delaware, U.S. while achieving optimization between model complexity (network depths) and accuracy. Results show that our proposed DL method (OA = 0.93, MIoU = 0.60) not only produced a higher classification accuracy than the traditional RF method (OA = 0.89, MIoU = 0.18) but also had a significantly reduced computational cost compared to established state-of-the-art CNNs (e.g., DeepLabV3+ and DANet) without loss of accuracy. The inclusion of multi-land cover proximity information (especially distances to forest and water) and the CNN-based self-supervised SAR denoising procedure can both enhance wetland classification accuracy, especially for forested wetland using traditional RF methods. These results demonstrated the novelty and efficiency of our proposed DL method for classifying wetlands by combing denoised SAR imagery and ancillary information, which provides insights on integration of DL approach and radar data for supporting operational wetland mapping at large spatial scales. © 2024 Elsevier B.V.

关键词： Self-supervised learning

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Effect of inverted T arrangement on AC pollution flashover characteristics of insulator strings

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High Voltage 2019年第2期4卷 97-104页

作者： Xingliang Jiang Xiaodong Ren Han Wang Xingbo Han Conglai Bi Zhiyu Li Ledong Hou State Key Laboratory of Power Transmission Equipment and System Security and New Technology College of Electrical EngineeringChongqing UniversityShapingba DistrictChongqing400044People's Republic of China

The arrangement of insulator strings has an effect on its pollution flashover characteristics.A new arrangement of insulator strings,inverted T-type arrangement,is proposed in this *** electric field distribution is simulated and the pollution flashover characteristics are tested in an artificial climate *** test results indicate that the inverted T-type arrangement can greatly improve the flashover voltage of polluted insulator strings,the‘7+2’inverted T-type arrangement can increase the flashover voltage of each insulator by 8.5%on average,and the‘3+3’inverted T-type arrangement can increase the flashover voltage of each insulator by 13.4%.The discharge process is different from that of the normal suspension string when the insulator string is inverted T-shaped,i.e.a local arc is produced at the low voltage end of the insulator string and develops downward along the suspension *** as for the horizontal tension string parts,it is difficult to generate arc during discharge development.

关键词： arrangement string pollution

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Practical fractional-order variable-gain super-twisting control with application to wafer stages of photolithography systems

arXiv

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arXiv 2021年

作者： Kuang, Zhian Sun, Liting Gao, Huijun Tomizuka, Masayoshi Research Institute of Intelligent Control and Systems Harbin Institute of Technology Harbin150001 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China Mechanical Control System Lab Mechanical Engineering Department University of California BerkeleyCA94720 United States

In this paper, a practical fractional-order variable-gain super-twisting algorithm (PFVSTA) is proposed to improve the tracking performance of wafer stages for semiconductor manufacturing. Based on the sliding mode control (SMC), the proposed PFVSTA enhances the tracking performance from three aspects: 1) alleviating the chattering phenomenon via super-twisting algorithm and a novel fractional-order sliding surface (FSS) design, 2) improving the dynamics of states on the sliding surface with fast response and small overshoots via the designed novel FSS and 3) compensating for disturbances via variable-gain control law. Based on practical conditions, this paper analyzes the stability of the controller and illustrates the theoretical principle to compensate for the uncertainties caused by accelerations. Moreover, numerical simulations prove the effectiveness of the proposed sliding surface and control scheme, and they are in agreement with the theoretical analysis. Finally, practice-based comparative experiments are conducted. The results show that the proposed PFVSTA can achieve much better tracking performance than the conventional methods from various perspectives. Copyright © 2021, The Authors. All rights reserved.

关键词： Sliding mode control

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Riboflavin-modified lipo-polyplexes co-delivering CXCR4 siRNA and doxorubicin for treatment of highly metastatic cancer

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Journal of Chinese Pharmaceutical Sciences 2021年第3期30卷 189-205页

作者： Kaisen Li Rudong Wang Yiwei Peng Dawen Dong Xianrong Qi Department of Pharmaceutics School of Pharmaceutical SciencesPeking University Health Science CenterBeijing 100191China Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery System School of Pharmaceutical SciencesPeking UniversityBeijing 100191China State Key Laboratory of Advanced Pharmaceutical Formulation with High Technology Yangtze River Pharmaceutical GroupJiangsu 225300China

SDF-1/CXCR4 has been recognized as one of the most relevant chemokine signaling pathways to cancer metastasis,and siRNA targeting CXCR4 may provide potential improvements to treat those highly metastatic cancers,especially when combined with *** the present study,we constructed riboflavin-modified lipo-polyplexes to co-deliver CXCR4 siRNA and doxorubicin for cancer *** was covalently conjugated to polyethyleneimine(PEI)with acid-cleavable hydrazine bond,and the obtained acid-sensitive conjugate was efficiently condensed with siRNA to form polyplexes,which were further coated with riboflavin-tailed lipid-membrane to prepare the lipo-polyplexes *** the fact that tumor cells overexpress riboflavin receptors,the riboflavin modification effectively enhanced uptake of lipo-polyplexes by tumor cells in a receptor-mediated *** riboflavin-modified lipo-polyplexes co-delivering CXCR4 siRNA and doxorubicin effectively decreased viability and invasiveness of tumor cells in vitro,and inhibited primary tumor growth and tumor metastasis in vivo.

关键词： Riboflavin Lipo-polyplexes Co-delivery SiRNA Doxorubicin

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Effect of SiO2 Nanoparticle's Size and Doping Concentration on AC Breakdown Behavior of Insulating Oil-based Nanofluids

Effect of SiO2 Nanoparticle's Size and Doping Concentration ...

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Conference on Electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： Muhammad Fasehullah Feipeng Wang Sidra Jamil Jingliang Huang Inzamam Ul Haq Qiuhuang Han State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China Laboratory of Luminescence Analysis and Molecular Sensing Ministry of Education School of Materials and Energy Southwest University Chongqing PR China

Insulating oil based nanofluids can effectively enhance the dielectric strength of insulating oil for their application in transformers. This work is performed to enhance the dielectric strength of synthetic ester (Midel 7131) and Mineral oil (Karamay #25) by using insulative SiO2 nanoparticles of two sizes (15nm & 50 nm) with four concentrations of 0.05 g/L, 0.2 g/L, 0.3 g/L, and 0.4 g/L. The AC breakdown voltages of SE-based nanofluids increase with increasing the doping concentration. Moreover, SiO2 (15nm) exhibits better dielectric strength due to the accumulation of charges at the liquid-solid interface. However, the AC breakdown voltage of mineral oil (MO) based nanofluids of both nanoparticle sizes first increases to a certain extent and then decreases with further increasing the doping concentration. This might be due to the small average distance of nanoparticles at higher doping concentrations. Furthermore, the AC breakdown voltage and increment percentage compared to pure oil at 1%, 10%, and 50% breakdown probabilities for SE and MO-based nanofluids were studied from Weibull probability distribution curves. Consequently, the variation in the breakdown voltage of nanofluids depends upon nanoparticles' size, doping concentration, and nature of nanoparticles (NPs).

关键词： Nanoparticles Silicon compounds Oils Doping Oil insulation Nanofluidics Probability distribution

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Diagonal-symmetrical and Midline-symmetrical Unit Cells with Same Porosity for Bone Implant: Mechanical Properties Evaluation

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Journal of Bionic Engineering 2019年第3期16卷 468-479页

作者： Jian Li Diansheng Chen Yingying Zhang Yan Yao Zhongjun Mo Lizhen Wang Yubo Fan Robotic Institute Beihang University Beijing 100191 China Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age and Disability and Key Laboratory of Rehabilitation Aids Technology and System of the Ministry of Civil Affairs National Research Center for Rehabilitation Technical Aids Beijing 100176 China Beijing Advanced Innovation Center for Biomedical Engineering Beihang University Beijing 100191 China Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education School of Biological Science and Medical Engineering Beihang University Beijing 100191 China

In this study, mechanical properties of bionic porous structures with diagonal-symmetrical and midline-symmetrical unit cells were studied when the porosities were same. Three typical unit cells (Diamond (DO), Rhombic Dodecahedron (RD), and Octet Truss (OT)) were selected, in which DO has diagonal-symmetrical shape, while RD and OT share midline-symmetrical structure. Based on the same porosity, corresponding models were designed, and Ti6Al4V samples were manufactured by electron beam melting. Then, using Mechanical Properties Testing (MPT) and Finite Element Analysis (FEA) methodologies, mechanical properties and transmissions of different porous structures were evaluated. Besides, composition and details before and after printing were analyzed with Energy Dispersive Spectrometer (EDS), X-ray diffraction (XRD) and Scanning Electron Microscope (SEM). MPT results showed that midline-symmetrical shape would have superior compressive performance than diagonal-symmetrical shape, but opposite trend for the torsion performance, which were in line with FEA prediction. Furthermore, effective modulus of DO, RD and OT were 2.59 GPa, 4.89 GPa, and 1.77 GPa, approximating the mechanical properties of human bones. Additionally, manufacturing defects and discrepancies between FEA and MPT were found. This study would provide great helps for unit cell selection and initial mechanical properties matching for optimum bone implants.

关键词： bionic design porous implant mechanical properties unit cell additive manufacturing 3D printing

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Beyond 60G SSB-FBMC signals transmission for Fiber-THz integrated system using simplified parallel Kramers-Kronig receiver

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Optics & Laser technology 2025年 191卷

作者： Long Zhang Jianjun Yu Xiongwei Yang Jianyu Long Chengzhen Bian Jingtao Ge Min Zhu Jiao Zhang Kaihui Wang Wen Zhou Purple Mountain Laboratories Southeast University Nanjing 211111 China State Key Laboratory of ASIC and System Key Laboratory for Information Science of Electromagnetic Waves (MoE) and the School of Information Science and Technology Fudan University Shanghai 200433 China Purple Mountain Laboratories Nanjing 211111 China

Simplifying coherent detection technology is a potential solution to save the cost of receivers in ultra-high data rate photon-assisted terahertz (THz) communication systems. A key issue when using an envelope detector to simplify the system is that the generation of signal-signal beat interference (SSBI) reduces the signal-to-noise ratio. The Kramers-Kronig (KK) receiver can effectively eliminate SSBI. In this paper, we propose and demonstrate a simplified parallel KK (SP-KK) receiver. The key idea is to use the Taylor expansion approximation instead of the nonlinear operation that significantly broadens the spectrum, and to use a multiplier-free finite impulse response (FIR) filter to approximate the Hilbert transform (HT). We evaluate the performance of the proposed SP-KK receiver in a single-channel 63.1 Gb/s transmission at 0.1 THz over 10-km wired and 3-m wireless links by using the envelope detection for 16-QAM filter bank multicarrier (FBMC) signals. The experimental results show that the proposed SP-KK receiver exhibits similar performance to the conventional HT-based KK (HT-KK) receiver.

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