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A Hybrid Parallel Strategy for Isogeometric Topology Optimization via CPU/GPU Heterogeneous Computing

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Computer Modeling in Engineering & Sciences 2024年第2期138卷 1103-1137页

作者： Zhaohui Xia Baichuan Gao Chen Yu Haotian Han Haobo Zhang Shuting Wang The State Key Lab of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan430074China School of Mathematics and Computer Science Wuhan Polytechnic UniversityWuhan430048China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan430074China

This paper aims to solve large-scale and complex isogeometric topology optimization problems that consumesignificant computational resources. A novel isogeometric topology optimization method with a hybrid parallelstrategy of CPU/GPU is proposed, while the hybrid parallel strategies for stiffness matrix assembly, equationsolving, sensitivity analysis, and design variable update are discussed in detail. To ensure the high efficiency ofCPU/GPU computing, a workload balancing strategy is presented for optimally distributing the workload betweenCPU and GPU. To illustrate the advantages of the proposedmethod, three benchmark examples are tested to verifythe hybrid parallel strategy in this paper. The results show that the efficiency of the hybrid method is faster thanserial CPU and parallel GPU, while the speedups can be up to two orders of magnitude.

关键词： Topology optimization high-efficiency isogeometric analysis CPU/GPU parallel computing hybrid OpenMPCUDA

high-efficiency CNT-Si solar cells based on a collaborative system enabled by oxide penetration

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Nano Research 2022年第3期15卷 2497-2504页

作者： Xuewei Zhao Wenjing Xu Yizeng Wu Huaisheng Wu Zhiyuan Xia Huiyi Xu Yuanyuan Shang Jinquan Wei Anyuan Cao School of Materials Science and Engineering Peking UniversityBeijing 100871China School of Physics and Microelectronics Zhengzhou UniversityZhengzhou 450001China State Key Lab of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Carbon nanotube-silicon(CNT-Si)solar cells represent one of the alternative photovoltaic techniques with potential for low cost and high efficiency.Here,we report a method to improve solar cell performance by depositing conventional transitional metal oxides such as WO_(3)and establishing a collaborative system,in which CNTs are well-embedded within the WO_(3)layer and both of them are in close contact to Si substrate.This unique collaborative system optimizes the overall energy conversion process including the light absorption(antireflection by WO_(3)),carrier separation(forming quasi p-n junction)and charge collection(CNT conductive network throughout the oxide layer).Combining with our previous TiO_(2)-coating and HNO_(3)-doping techniques,a solar cell efficiency of>18%at an active area of 0.09 cm 2(air mass 1.5,100 mW/cm^(2))was achieved.The oxide-enhanced CNT-Si solar cells which integrate the advantages of traditional semiconductors and novel nanostructures represent a promising route toward next-generation high-performance silicon-based photovoltaics.

关键词： carbon nanotube-silicon(CNT-Si)solar cell high-efficiency WO_(3) collaborative system

Toward high-efficiency perovskite solar cells with one-dimensional oriented nanostructured electron transport materials

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Journal of Energy Chemistry 2023年第7期82卷 66-87,I0003页

作者： Yinhua Lv Bing Cai Ruihan Yuan Yihui Wu Quinn Qiao Wen-Hua Zhang Yunnan Key Laboratory of Carbon Neutrality and Green Low-carbon Technologies School of Materials and EnergyYunnan UniversityKunming 650500YunnanChina School of Chemical Engineering Sichuan UniversityChengdu 610065SichuanChina Sichuan Research Center of New Materials Institute of Chemical MaterialsChina Academy of Engineering PhysicsChengdu 610200SichuanChina Mechanical and Aerospace Engineering Syracuse UniversitySyracuseNew York 13244USA Yunnan University and Southwest United Graduate School Kunming 650500YunnanChina

The unique advantages of one-dimensional(1D)oriented nanostructures in light-trapping and chargetransport make them competitive candidates in photovoltaic(PV)devices.Since the emergence of perovskite solar cells(PSCs),1D nanostructured electron transport materials(ETMs)have drawn tremendous interest.However,the power conversion efficiencies(PCEs)of these devices have always significantly lagged behind their mesoscopic and planar counterparts.high-efficiency PSCs with 1D ETMs showing efficiency over 22%were just realized in the most recent studies.It yet lacks a comprehensive review covering the development of 1D ETMs and their application in PSCs.We hence timely summarize the advances in 1D ETMs-based solar cells,emphasizing on the fundamental and optimization issues of charge separation and collection ability,and their influence on PV performance.After sketching the classification and requirements for high-efficiency 1D nanostructured solar cells,we highlight the applicability of 1D TiO_(2)nanostructures in PSCs,including nanotubes,nanorods,nanocones,and nanopyramids,and carefully analyze how the electrostatic field affects cell performance.Other kinds of oriented nanostructures,e.g.,ZnO and SnO_(2)ETMs,are also described.Finally,we discuss the challenges and propose some potential strategies to further boost device performance.This review provides a broad range of valuable work in this fast-developing field,which we hope will stimulate research enthusiasm to push PSCs to an unprecedented level.

关键词： 1D nanostructures Perovskite solar cells Electron transport materials Electrostatic field high-efficiency

high-efficiency tea shoot detection method via a compressed deep learning model

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International Journal of Agricultural and Biological Engineering 2022年第3期15卷 159-166,F0003页

作者： Yatao Li Leiying He Jiangming Jia Jianneng Chen Jun Lyu Chuanyu Wu Faculty of Mechanical Engineering&Automation Zhejiang Sci-Tech UniversityHangzhou 310018China Key Laboratory of Transplanting Equipment and Technology of Zhejiang Province Hangzhou 310018China School of Information Science and Technology Zhejiang Sci-Tech UniversityHangzhou 310018China

Achieving high-efficiency and accurate detection of tea shoots in fields are essential for tea robotic plucking. A real-time tea shoot detection method using the channel and layer pruned YOLOv3-SPP deep learning algorithm was proposed in this study. First, tea shoot images were collected and data augmentation was performed to increase sample diversity, and then a spatial pyramid pooling module was added to the YOLOv3 model to detect tea shoots. To simplify the tea shoot detection model and improve the detection speed, the channel pruning algorithm and layer pruning algorithm were used to compress the model. Finally, the model was fine-tuned to restore its accuracy, and achieve the fast and accurate detection of tea shoots. The test results demonstrated that the number of parameters, model size, and inference time of the tea shoot detection model after compression reduced by 96.82%, 96.81%, and 59.62%, respectively, whereas the mean average precision of the model was only 0.40% lower than that of the original model. In the field test, the compressed model was deployed on a Jetson Xavier NX to conduct the detection of tea shoots. The experimental results demonstrated that the detection speed of the compressed model was 15.9 fps, which was 3.18 times that of the original model. All the results indicate that the proposed method could be deployed on tea harvesting robots with low computing power to achieve high efficiency and accurate detection.

关键词： deep learning tea shoot detection model compression high-efficiency

Multifunctional geometric phase optical element for high-efficiency full Stokes imaging polarimetry

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Photonics Research 2019年第9期7卷 1066-1074页

作者： YANMENG DAI YUQUAN ZHANG YOUPENG XIE DAPENG WANG XIANYOU WANG ITING LEI CHANGJUN MIN XIAOCONG YUAN Nanophotonics Research Center Shenzhen Key Laboratory of Micro-Scale Optical Information Technology Shenzhen University

Polarization imaging finds applications in many areas, such as photoelasticity, ellipsometry, and biomedical imaging. A compact, snapshot, and high-efficiency imaging polarimeter is highly desirable for many applications.Here, based on a single multifunctional geometric phase optical element(GPOE), a new method is proposed for high-efficiency snapshot imaging polarimetry. With tailored spatially varying orientation of each anisotropic unit cell, the GPOE works highly efficiently as both a spin sorter and a half-wave plate, enabling snapshot retrieving of a full Stokes vector of incident light. The designed GPOE is implemented in the form of liquid crystal fabricated with a photo-alignment technology, and its application in imaging polarimetry is experimentally demonstrated by retrieving full Stokes parameters of a cylinder vector beam. This method can also work in the form of plasmonic or dielectric metasurfaces, enabling ultra-compact polarization detection systems by monolithic integration with other devices such as metalenses.

关键词： red Stokes Multifunctional geometric phase optical element for high-efficiency full Stokes imaging polarimetry

Adiabatic cooling for cold polar molecules on a chip using a controllable high-efficiency electrostatic surface trap

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Chinese Physics B 2014年第12期23卷 148-154页

作者：李胜强许亮夏勇汪海玲印建平 State Key Laboratory of Precision Spectroscopy Department of Physics East China Normal University

We propose a controllable high-efficiency electrostatic surface trap for cold polar molecules on a chip by using two insulator-embedded charged rings and a grounded conductor plate. We calculate Stark energy structure pattern of ND3 molecules in an external electric field using the method of matrix diagonalization. We analyze how the voltages that are applied to the ring electrodes affect the depth of the efficient well and the controllability of the distance between the trap center and the surface of the chip. To obtain a better understanding, we simulate the dynamical loading and trapping processes of ND3 molecules in a ｜J, KM = ｜1,-1 state by using classical Monte–Carlo method. Our study shows that the loading efficiency of our trap can reach ～ 88%. Finally, we study the adiabatic cooling of cold molecules in our surface trap by linearly lowering the potential-well depth（i.e., lowering the trapping voltage）, and find that the temperature of the trapped ND3 molecules can be adiabatically cooled from 34.5 m K to ～ 5.8 m K when the trapping voltage is reduced from-35 k V to-3 k V.

关键词： controllable high-efficiency surface trap cold polar molecules

high-efficiency Phosphorescent White Organic Light-Emitting Diodes with Stable Emission Spectrum Based on RGB Separately Monochromatic Emission Layers

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Chinese Physics Letters 2014年第4期31卷 122-125页

作者： ZHANG Zhi-Qiang LIU Yi-Peng DAI Yan-Feng CHEN Jiang-Shan MA Dong-Ge ZHANG Hong-Mei State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chan~chun 130022 University of Chinese Academy of Sciences Beijing 100049 Department of Materials Science and Engineering Nanjing University of Posts and Telecommunications Nanjing 210023

highly efficient phosphorescent white organic light-emitting diodes （WOLEDs） with stable emission spectra are successfully fabricated by using an RGB three-color separately monochromatic emission layer （EML） struc- ture. The EML consists of a sequence of bis（2-methyldibenzo[f, h]quinoxaline）（acetylacetonate） iridium （Ⅲ）（Ir（MDQ）2（acac）） doped tris（4-carbazoyl-9-ylphenyl）amine （TCTA） as the red emission layer, iridium, tris（2- phenylpyidine）（Ir（ppy）3） doped TCTA as the green emission layer and iridium（Ill） Ibis（4, 6-difuorophenyl）- pyridinato-N, C2＇]picolinate （FIrpic） doped a mixed-host of TCTA and tris（4-carbazoyl-9-ylphenyl）amine （26DCz PPy） as the blue emission layer. Without using any out-coupling techniques, the resulting WOLEDs achieve a power efficiency of 421m/W at lOO cd/m2, and 34 lm/W at 1000 cd/m2. The WOLEDs also show excellent spec- trum stability with bias voltages, remaining the Commission Internationale de L＇Eclairage coordinates at （0.44, 0.43） from 1000 cd/m2 to 10000 cd/m2 and the color rendering index is as high as over 80. We contribute the sta- ble emission spectrum to the RGB separate EML structure that successfully suppresses the undesired competition between host-guest energy transfer and direct exciton formation on emissive dopants by effectively controlling the position of exciton recombination region.

关键词： Layers high-efficiency red emission

Special issue： Technologies for future high-efficiency industrial silicon wafer solar cells

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Frontiers in Energy 2017年第1期11卷 1-3页

作者： Dr. Wenzhong SHEN Dr. Bram HOEX Professor Shanghai Jiao Tong University China

In this special issue we have twelve articles from researchers in Australia and China that discuss various aspects related to technology which could be imple- mented in the near term in industrial silicon wafer solar cells. In the recent years we have seen the introduction of the passivated emitter rear contact （PERC） solar cell, which was invented at UNSW Australia in the 1980s.

关键词： Technologies high-efficiency wafer

Design of high-efficiency broadband power amplifier using low-pass bias network

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The Journal of China Universities of Posts and Telecommunications 2016年第1期23卷 91-96页

作者： Yu Qijin Yu Cuiping Tang Bihua Liu Yuan'an School of Electronic Engineering Beijing University of Posts and Telecommunications

A novel design of high-efficiency broadband power amplifier （BPA） with the low-pass bias networkto enhance the efficiency and output power is presented in this paper. Compared with other bias networks, the proposed low-pass bias network shows a smaller baseband impedance, which can reduce the electrical memory effect. While it provides a larger radio frequency （RF） impedance, which can prevent the leakage of the output power from bias network. A BPA with the proposed bias network is designed using commercial GaN device Cree40025F. The designed BPA shows a fractional bandwidth of 40%, from 1.8 GHz to 2.7 GHz. The measured results exhibit 73.9 % drain efficiency （DE） value with output power of 43.5 dBm at 2.7 GHz, which appears an enhancement of 9.5% and 2.5 dBm comparing with that adopts LC bias network.

关键词： broadband power amplifier low-pass bias network high-efficiency broadband