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High Power GaN Doubler with High Duty Cycle Pulse Based on Local Non-Reflection Design

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Chinese Journal of Electronics 2024年

作者： Yazhou DONG tianchi ZHOU Shixiong LIANG Guodong GU Hongji ZHOU Jianghua YU Hailong GUO Yaxin zhang School of Electronic Engineering University of Electronic Science and Technology of China National Key Laboratory of Solid-State Microwave Devices and Circuits Hebei Semiconductor Research Institute

The study focuses on the development of gallium nitride(GaN) Schottky barrier diode(SBD) frequency doublers for terahertz technology. The low conversion efficiency of these doublers limits their practical applications. To address this challenge, the paper proposes a multi-objective local no-reflection design method based on a three-dimensional electromagnetic structure. The method aims to improve the coupling efficiency of input power and reduce the reflection of power output. Experimental results indicate that the proposed method significantly improves the performance of GaN SBD frequency doublers, achieving an efficiency of 16.9% and a peak output power of 160m W at 175 GHz. These results suggest that the method can contribute to the further development of GaN SBD frequency doublers for terahertz technology.

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Solidification microstructure evolution and its correlations with mechanical properties and damping capacities of Mg-Al-based alloy fabricated using wire and arc additive manufacturing

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Journal of Materials Science & Technology 2023年第13期144卷 28-44页

作者： Zihong Wang Jingfeng Wang Xin Lin Nan Kang tianchi zhang Yanfang Wang Li Wang Cong Dang Weidong Huang College of Materials Science and Engineering Chongqing UniversityChongqing 400045China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical UniversityXi’an 710072China Arts et Métiers Institute of Technology MSMPHESAM UniversitéChâlons-en-Champagne F-51006France Chongqing Construction Science Research Institute Chongqing 401147China

Magnesium(Mg)alloys,as the lightest metal structural material with good damping capacities,have im-portant application prospects in realizing structural lightweight and vibration reduction.However,their engineering application is greatly limited by poor plastic formability.Wire and arc additive manufactur-ing(WAAM)provides a potential approach for fabricating large-scale Mg alloy components with high manufacturing flexibility.In this study,the evolution of the solidification microstructure of a WAAM-processed Mg-Al-based alloy was quantitatively analyzed based on the analytical models;then,the cor-relations between the solidification microstructure and mechanical properties/damping capacities were investigated.The results revealed that the WAAM-processed Mg-Al-based alloy with an equiaxed-grain-dominated microstructure displayed a simultaneous enhancement in mechanical properties and damping capacities compared to those of the cast Mg-Al-based alloy.The good combination of mechanical prop-erties and damping capacities are mainly attributed to the weakened basal texture with a relatively high Schmid factor for basalslip,the twinning-induced plasticity(TWIP)effect associated with the profuse{10-12}tensile twinning,and the relatively high dislocation density caused by the thermal stress during the WAAM process.

关键词： Wire and arc additive manufacturing Magnesium alloy Microstructure evolution Mechanical properties Damping capacities

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深度学习驱动的水下图像处理研究进展

计算机科学 2024年第S1期51卷 271-282页

作者：张天驰刘宇轩重庆交通大学信息科学与工程学院重庆400074

随着人工智能和水下设备的发展,水下机器人能够便捷地获取水下图像。水下图像对于海洋的探索和开发等活动至关重要,但由于水下成像环境十分复杂,导致获取到的水下图像成像质量较低,具有低对比度、模糊和颜色失真等退化问题,难以满足水... 详细信息

随着人工智能和水下设备的发展,水下机器人能够便捷地获取水下图像。水下图像对于海洋的探索和开发等活动至关重要,但由于水下成像环境十分复杂,导致获取到的水下图像成像质量较低,具有低对比度、模糊和颜色失真等退化问题,难以满足水下生产活动的要求。近年来,基于深度学习的水下图像处理方法和质量评价指标发展迅速,受到诸多学者的关注。目前已有基于深度学习的水下图像处理方法的综述,但仍存在总结不够全面及缺少最新研究成果等问题。因此,文中首先分析水下图像退化成因并提出所需处理的问题,根据各类算法的原理特点将水下图像处理方法进行分类;其次,详细分析和归纳了基于深度学习的水下图像处理最新研究成果,总结出各类算法的主要特征;然后,详细整理了现有的公开水下图像数据集和当前主流以及最新的基于学习的水下图像质量评测指标,并通过设计实验将传统算法和基于深度学习的水下图像处理方法进行对比分析;最后,分析总结了一些水下图像处理领域尚未解决的问题,并对未来的发展方向进行展望。

关键词：深度学习水下机器人水下图像图像处理图像质量评测

Host plant traits play a crucial role in shaping the composition of epiphytic microbiota in the arid desert,Northwest China

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Journal of Arid Land 2024年第5期16卷 699-724页

作者： zhang Jun zhang Yuanming zhang Qi State Key Laboratory of Desert and Oasis Ecology Key Laboratory of Ecological Safety and Sustainable Development in Arid LandsXinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China Xinjiang Key Laboratory of Biodiversity Conservation and Application in Arid Lands Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China Xinjiang Field Scientific Observation Research Station of Tianshan Wild Fruit Forest Ecosystem Yili Botanical GardenXinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China College of Life Sciences Shihezi UniversityShihezi 832003China

Phyllosphere microorganisms are a crucial component of environmental microorganisms,highly influenced by host characteristics,and play a significant role in plant health and productivity.Nonetheless,the impact of host characteristics on shaping phyllosphere microbial communities of plants with different life forms remains ambiguous.Utilizing high-throughput sequencing technology,this study analyzed the diversity and community composition of phyllosphere epiphytic microorganisms(e.g.,bacteria and fungi)of various plant life forms in the hinterland of the Gurbantunggut Desert,Northwest China.Functional annotation of prokaryotic taxa(FAPROTAX)and fungi function guild(FUNGuild)were employed to assess the ecological functions of microorganisms and to investigate the role of stochastic and deterministic processes in shaping phyllosphere microbial communities.Result showed a diverse array of phyllosphere epiphytic microorganisms in the desert plants,with Proteobacteria,Cyanobacteria,and Actinobacteriota dominating bacterial community,while Ascomycota and Basidiomycota were prevalent in fungal community.Comparison across different plant life forms highlighted distinct microbial communities,indicating strong filtering effects by plant characteristics.FAPROTAX prediction identified intracellular parasites(accounting for 27.44%of bacterial community abundance),chemoheterotrophy(10.12%),and phototrophy(17.41%)as the main functions of epiphytic bacteria on leaves of different life form plants.FUNGuild prediction indicated that phyllosphere epiphytic fungi primarily served as Saprotrophs(81.77%),Pathotrophs(17.41%),and Symbiotrophs(0.82%).Co-occurrence network analysis demonstrated a predominance of positive correlations among different microbial taxa.Raup-Crick dissimilarity index analysis revealed that deterministic processes predominantly influenced phyllosphere bacterial and fungal community assembly.Variance partitioning analysis and random forest modeling suggested that plant leaf functional traits significantly impacted

关键词： phyllosphere epiphytic bacteria phyllosphere epiphytic fungi community structure community diversity functional diversity plant life form plant functional traits

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3m污水管下穿隧道不断流改迁施工技术

工程建设（维泽科技） 2024年第8期7卷 151-154页

作者：张天池中国水利水电第十一工程局有限公司河南郑州450000

随着现代化城市的不断发展,在针对于城市基础进行建设过程当中,下穿隧道包括地铁等一系列的工程已经变得越来越多,在隧道下穿污水管道目前已经成为了建设工程当中比较常见的一项工程。因此在本篇文章当中也会针对于3m污水管下穿隧道不... 详细信息

随着现代化城市的不断发展,在针对于城市基础进行建设过程当中,下穿隧道包括地铁等一系列的工程已经变得越来越多,在隧道下穿污水管道目前已经成为了建设工程当中比较常见的一项工程。因此在本篇文章当中也会针对于3m污水管下穿隧道不断流改迁技术进行相应的探究,希望能够更好地推动城市建设过程当中的污水管改迁工程的顺利实施。

关键词：污水管道下穿隧道 L型路由污水管改迁

基于用户画像和链路预测的电影个性化推荐研究

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系统科学与数学 2024年第6期44卷 1586-1607页

作者：周晨曦赵天驰张玲玲中国科学院大学经济与管理学院北京100190 中国科学院大数据挖掘与知识管理重点实验室北京100190 中国科学院大学数字经济监测预测预警与政策仿真教育部哲学社会科学实验室(培育) 北京100190

当今电影市场上海量的影片资源使用户面临选择困境,高效的电影推荐系统对提升用户体验以及电影服务商的市场竞争力具有重要作用.如何融合多种数据源进行个性化推荐,在提升算法精度的同时平衡多样性是电影推荐系统面临的挑战,针对该问题... 详细信息

当今电影市场上海量的影片资源使用户面临选择困境,高效的电影推荐系统对提升用户体验以及电影服务商的市场竞争力具有重要作用.如何融合多种数据源进行个性化推荐,在提升算法精度的同时平衡多样性是电影推荐系统面临的挑战,针对该问题的研究具有重要的理论和现实意义.用户画像可以从多维度刻画丰富的用户特征,更好地理解用户兴趣和行为,链路预测从网络拓扑结构视角建模具有独特优势,二者的融合为解决上述问题提供了可能性.为此,该研究提出了一种基于用户画像和链路预测的电影个性化推荐算法.该算法以电影推荐为背景,区分了用户的行为和领域兴趣相似性,融合多源数据构建用户画像,作为网络外部信息融入链路预测过程中,有助于提升算法精度.此外,算法还从稀缺性视角改进了二分图投影中用户兴趣相似性的计算,同时衡量了链接在推荐中的促进或抑制作用强度,使推荐结果更加新颖和个性化,流行度偏差问题得到一定程度的改善.最后,文章基于两个MovieLens数据集对提出的推荐算法进行了实验验证,结果表明与代表性算法相比,文章提出的算法不仅在准确性上有显著提升,在与多样性相关的指标上也有明显的优势.此外,抽象出的用户画像能够帮助推荐平台了解其用户群,从而制定出更为科学的营销与管理策略.

关键词：个性化推荐链路预测用户画像二分图稀缺性视角

Highly transmitted silver nanowires-SWCNTs conductive flexible film by nested density structure and aluminum-doped zinc oxide capping layer for flexible amorphous silicon solar cells

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Journal of Materials Science & Technology 2022年第31期126卷 152-160页

作者： Shunliang Gao Xiaohui Zhao Qi Fu tianchi zhang Jun Zhu Fuhua Hou Jian Ni Chengjun Zhu Tiantian Li Yanlai Wang Vignesh Murugadoss Gaber A.M.Mersal Mohamed M.Ibrahim Zeinhom M.El-Bahy Mina Huang Zhanhu Guo The Key Laboratory of Semiconductor Photovoltaic Technology at Universities of Inner Mongolia Autonomous Region College of Physical Science and TechnologyInner Mongolia UniversityHohhot 010021China Department of Electronic Science and Technology School of Electronic Information and Optical EngineeringNankai UniversityTianjin 300350China Advanced Materials Division Engineered Multifunctional Composites(EMC)Nanotech LLCKnoxvilleTN 37934United States Integrated Composites Laboratory(ICL) Department of Chemical and Bimolecular EngineeringUniversity of TennesseeKnoxvilleTN 37996United States Department of Chemistry College of ScienceTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia Department of Chemistry Faculty of ScienceAl-Azhar UniversityNasr City 11884CairoEgypt College of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China

Indium tin oxide(ITO)is widely used in transparent conductive films(TCFs);however,several disadvan-tages,such as high cost and toxicity of indium,limit its applications.Therefore,it is necessary to develop other materials that can replace ITO.Silver nanowires or single walled carbon nanotubes(SWCNTs)have attracted considerable interest owing to their unique electrical,optical,and thermal stabilities,and thus,they are ideal for transparent electrodes for flexible or stretchable devices.In this study,we develop a novel architecture of composite TCFs on a polyethylene naphthalate(PEN)flexible substrate.Herein,the silver nanowires-SWCNTs films with nested density structure were fabricated through ultrasonic spraying technology by varying the spraying width.For achieving enhanced transmittance,we combined the larger irregular grids and holes with fewer nanowires stacked in the longitudinal direction,more optical chan-nels,and good carrier transport.Thereafter,aluminum-doped zinc oxide(AZO)was used as capping to the structure for enhancing the optical properties of the TCFs.The silver nanowires-SWCNTs/AZO(ASA)bilayer was obtained in the optimized architecture,which showed superior optoelectronic performance to that shown by commercial ITO with a high optical transmittance of 92%at the wavelength of 550 nm and low sheet resistance of 17/sq.In the specially structured conductive film,the significant improvement in the transmittance and uniformity of the sheet resistance was attributed to the effective nanowire junc-tion contact compared to that in ordinary structure of silver nanowires,which reduced the mean density of small clusters of nanowires.Compared with the silver nanowires-SWCNTs films,the ASA bilayer film exhibited excellent resistance to boiling,mechanical bending(10,000 cycles),and CO_(2)plasma.Moreover,the sheet resistance of ASA changed slightly after the tape tests,thereby illustrating a strong adhesion to the PEN substrate after the enclosure of AZO.Meanwhile,the AZO capping layer can enhance the op-tical

关键词： Silver nanowires-SWCNTs Nested density TCFs Flexible substrate Photovoltaic devices

大数据技术在医院电子病历信息管理系统中的应用

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移动信息 2024年第2期46卷 38-40页

作者：张天驰安徽医科大学附属巢湖医院信息中心安徽巢湖238000

文中旨在解决医院电子病历信息管理系统存在的问题,探究大数据技术在该领域中的应用。首先,介绍了大数据技术在医院电子病历信息管理系统中的应用优势,包括对海量数据的高效处理和深度挖掘、提供全面且准确的数据支持、提高临床决策效... 详细信息

文中旨在解决医院电子病历信息管理系统存在的问题,探究大数据技术在该领域中的应用。首先,介绍了大数据技术在医院电子病历信息管理系统中的应用优势,包括对海量数据的高效处理和深度挖掘、提供全面且准确的数据支持、提高临床决策效能等。其次,分析了医院电子病历信息管理系统存在的不足,包括病历信息不规范、数据存储不完整、数据分析效率较低等。最后,提出了大数据技术在医院电子病历信息管理系统中的应用措施,包括构建完善的数据标准化体系、实现数据可视化和智能决策、利用机器学习算法进行数据挖掘等。通过上述措施,提高了医院电子病历管理的智能化水平和临床决策效能,可为相关人员提供参考。

关键词：大数据技术医院电子病历信息管理系统

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深圳创投行业发展历程及战略研究

特区实践与理论 2024年第1期 64-72页

作者：张韶辉徐雅婷胡天池资本市场学院

创业投资在金融发展和金融体系中扮演着重要的角色,通过提供资金、对接产业和资本市场等方式对企业技术创新起到重要的支持作用,进而推动地区产业升级。过去二十多年,深圳创投行业蓬勃发展,创造出一批批由创投机构扶持成长的高科技龙头... 详细信息

创业投资在金融发展和金融体系中扮演着重要的角色,通过提供资金、对接产业和资本市场等方式对企业技术创新起到重要的支持作用,进而推动地区产业升级。过去二十多年,深圳创投行业蓬勃发展,创造出一批批由创投机构扶持成长的高科技龙头企业,为深圳打造全球科技创新高地提供了极大支持。深圳创投业还为全国创投业带来了创业、创新、创投协同发展的“深圳模式”,成为全国创投业的领军城市。文章通过回溯深圳创投行业近三十年来的探索和发展历程,总结深圳创投行业现状及存在的问题,就深圳创投行业如何进一步支持科技创新、完善深圳创新生态系统建设等提出政策建议。

关键词：创业投资科技创新创新生态系统