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Seismic performance of precast bridge columns connected with grouted corrugated-metal duct through biaxial quasi-static experiment and modeling

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Earthquake Engineering and Engineering Vibration 2021年第3期20卷 747-770页

作者： Xia zhanghua Lin Shangshun He Yongbo Ge Jiping Sun Jinlei Department of Civil Engineering Fuzhou UniversityFuzhou 350116China Department of Civil Engineering Fujian University of TechnologyFuzhou 350116China Department of Civil Engineering Shanghai Institute of TechnologyShanghai 201418China

In this paper,the seismic behaviors of precast bridge columns connected with grouted corrugated-metal duct(GCMD)were investigated through the biaxial quasi-static experiment and numerical *** a geometric scale ratio of 1:5,five specimens were fabricated,including four precast bridge columns connected with GCMD and one cast-in-place(CIP)bridge column.A finite element analysis model was also established by using OpenSees and was then calibrated by using the experimental results for parameter *** results show the biaxial seismic performance of the precast bridge columns connected with GCMD was similar to the CIP bridge columns regarding ultimate bearing capacity and hysteresis energy,and further,that it could meet the design goal of equivalent *** seismic performance of the precast bridge columns connected with GCMD deteriorated more significantly under bi-directional load than under uni-directional load.A proper slenderness ratio(e.g.,7.0-10.0)and longitudinal reinforcement ratio could significantly improve the energy dissipation capacity and deformation capacity of the precast bridge columns,while the axial load ratio and concrete strength had little influence on the above *** research results could bring insights to the development of the seismic design of precast bridge columns connected with GCMD.

关键词： precast bridge column cast-in-place column grouted corrugated-metal duct connection biaxial quasi-static test seismic performance hysteresis energy

Passive Intermodulation Measurement:Challenges and Solutions

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Engineering 2022年第7期8卷 181-191页

作者： zhanghua Cai Lie Liu Francesco de Paulis Yihong Qi General Test Systems Inc. Shenzhen 518000China College of Electrical and Information Engineering Hunan UniversityChangsha 410082China UAq EMC Laboratory Department of Industrial and Information Engineering and EconomicsUniversity of L’AquilaL’Aquila 64100Italy

In modern wireless communication systems,the signal-to-noise ratio(SNR)is one of the most important performance *** the other radio frequency(RF)performance of the components is well designed,passive intermodulation(PIM)interference may become an important factor limiting the system’s *** it is a base station,an indoor distributed antenna system,or a satellite system,there are stringent PIM level requirements to minimize interference and enhance network capacity in multicarrier *** for systems of high power and wide bandwidth such as 5G wireless communication,PIM interference is even more *** to the complexity and uncertainty of PIM,measurement is the most important means to study and evaluate the PIM performance of wireless communication *** this review,the current main PIM measurement methods recommended by International Electrotechnical Commission(IEC)and other standard organizations are introduced,and several key challenges in PIM measurement and their solutions(including the design of PIM tester,the location of the PIM sources,the design of compact PIM anechoic chambers,and the evaluation methods of PIM anechoic chambers)are *** challenges are of great significance to solve PIM problems that may arise during device characterization and verification in real wireless communication systems.

关键词： Passive intermodulation(PIM) PIM source location Anechoic chamber

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自制着色底板和光谱特征检测竹叶面积

实验室研究与探索 2024年第2期43卷 39-44页

作者：贺安琪李彬许章华杨远垚李增禄福州大学环境与安全工程学院福州350108 福建省资源环境监测与可持续经营利用重点实验室福建三明365004

为快速准确地检测健康与病态竹叶单叶面积,提出一种基于自制着色底板和光谱特征(CBP-SF)的叶面积检测方法。根据叶片光谱特征设计底板,然后利用波段计算、碎片过滤和自适应阈值方法进行图像分割,再根据竹叶大小进行参照物切割,最后统计... 详细信息

为快速准确地检测健康与病态竹叶单叶面积,提出一种基于自制着色底板和光谱特征(CBP-SF)的叶面积检测方法。根据叶片光谱特征设计底板,然后利用波段计算、碎片过滤和自适应阈值方法进行图像分割,再根据竹叶大小进行参照物切割,最后统计叶片区域和参考矩形框的像元数并计算叶面积。与随机森林(RF)、最大类间方差法(OTSU)和叶面积仪法(LAM)的对比结果表明:对于健康竹叶的检测效果,CBP-SF>RF>OTSU=LAM;对于病态竹叶的检测效果,CBP-SF>RF>OTSU>LAM;对于全样本竹叶的检测效果,CBP-SF>RF>OTSU>LAM。CBP-SF具备检测健康与病态竹叶单叶面积的能力。

关键词：着色底板光谱特征图像分割竹叶叶面积检测

Methanogenesis acceleration of fresh landfilled waste by micro-aeration

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Journal of Environmental Sciences 2005年第3期17卷 371-374页

作者： SHAOLi-ming HEPin-jing zhanghua YUXiao-hua LIGuo-jian StateKeyLaboratoryofPollutionControlandReclamation TongjiUniversityShanghai20092China

When municipal solid waste(MSW) with high content of food waste is landfilled, the rapid hydrolysis of food waste results in the imbalance of anaerobic metabolism in the landfill layer, indicated by accumulation of volatile fatty acids(VFA) and decrease of pH value. This occurrence could lead to long lag time before the initiation of methanogenesis and to the production of strong leachate. Simulated landfill columns with forced aeration, with natural ventilation, and with no aeration, were monitored regarding their organics degradation rate with leachate recirculation. Hydrolysis reactions produced strong leachate in the column with no aeration. With forced aeration, the produced VFA could be effectively degraded, leading to the reduction in COD of the leachate effluent since the week 3. The CH_4 in the landfill gas from the column with aeration rate of 0.39 m3/(m3·d) and frequency of twice/d, leachate recirculation rate of 12.2 mm/d and frequency of twice/d, could amount to 40%(v/v) after only 20 weeks. This amount had increased up to 50% afterward even with no aeration. Most of COD in the recirculated leachate was removed. Using natural ventilation, CH_4 could also be produced and the COD of the leachate effluent be reduced after 10 weeks of operation. However, the persistent existence of oxygen in the landfill layer yielded instability in methanogenesis process.

关键词： MSW landfill methanogenesis leachate recirculation forced aeration natural ventilation

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跨尺度蒸馏特征感知的轻量化水下图像增强

大气与环境光学学报 2024年第3期19卷 381-390页

作者：吴晓华李增禄许章华周景春三明学院艺术设计学院福建三明365004 三明学院网络技术中心福建三明365004 三明学院福建省资源环境监测与可持续经营利用重点实验室福建三明365004 福州大学地理与生态环境研究院福建福州350108 大连海事大学信息科学技术学院辽宁大连116026

水下图像增强技术能够提升水下图像的质量和可视性,在丰富数字媒体资源、水下探测、水下通信等领域具有重要应用价值。近年来,深度学习方法在水下图像增强方面取得了显著的效果。然而,现有的方法计算复杂度高,限制了它们在计算资源有限... 详细信息

水下图像增强技术能够提升水下图像的质量和可视性,在丰富数字媒体资源、水下探测、水下通信等领域具有重要应用价值。近年来,深度学习方法在水下图像增强方面取得了显著的效果。然而,现有的方法计算复杂度高,限制了它们在计算资源有限的场景中的使用。针对这一问题,提出了一种轻量化的水下图像增强方法,该方法基于跨尺度深度蒸馏特征感知,采用U型网络结构,在保证非线性抽象层级抽取的同时,大幅减少了模型参数量。实验结果表明,所提出方法在视觉效果和客观评价指标上均取得了具有竞争力的结果。

关键词：水下图像增强轻量化跨尺度蒸馏特征 U型网络

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气泡对浮选精煤压滤压力及脱水性能影响机理

洁净煤技术 2024年第5期30卷 172-179页

作者：杨长华董宪姝陈茹霞樊玉萍马晓敏冯泽宇太原理工大学矿业工程学院山西太原030024 太原理工大学安全与应急管理工程学院山西太原030024

起泡剂的加入使得煤泥浮选过程中产生稳定性强、黏度高、难以破灭的泡沫,大量泡沫的堆积严重制约了浮选精煤的压滤脱水效果。为探明气泡对浮选精煤的压滤压力及脱水性能的影响机理,使用新型加压脱水装置研究气泡对浮选精煤压滤压力、滤... 详细信息

起泡剂的加入使得煤泥浮选过程中产生稳定性强、黏度高、难以破灭的泡沫,大量泡沫的堆积严重制约了浮选精煤的压滤脱水效果。为探明气泡对浮选精煤的压滤压力及脱水性能的影响机理,使用新型加压脱水装置研究气泡对浮选精煤压滤压力、滤饼位移、滤液质量及滤饼水分的影响规律,并通过ImageJ图像处理、流变特性测试、FBRM试验和SEM表征等一系列方法对脱水机理进行探究。压滤结果表明,充气量为0.3 m ^(3)/h时,浮选精煤压滤所需压力由451.2 kg增至540.7 kg,滤饼水分增加10.7个百分点。ImageJ图像处理表明小直径气泡分布占比随充气量的增大而增大,流变性测试表明随充气量增加,浮选精煤黏度增大且动切力τ0由0.9947 mPa增至1.1703 mPa,说明颗粒定向重排作用增强;FBRM试验表明气泡的存在使浮选精煤粒径增大,发生凝聚现象,颗粒间相互作用力增大;SEM结果表明气泡使浮选精煤颗粒聚集现象明显。气泡的存在导致浮选精煤颗粒排列更加紧密,颗粒间毛细半径减小,过滤所需压力增大,同时滤饼孔隙变小,水分迁移路径更复杂,不利于水分脱除。

关键词：气泡压滤压力颗粒相互作用脱水机理

基于HPLC-ESI-MS^(n)和指纹图谱结合化学计量评价不同生长年限铁皮石斛黄酮类成分差异

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食品工业科技 2024年第18期45卷 239-249页

作者：李运容黄国东李锦妍吴樟桦陈松黄月纯魏刚广西中医药大学附属国际壮医医院广西南宁530201 广州中医药大学中药学院广东广州510006 广州中医药大学第一附属医院广东广州510405

目的:分析广西铁皮兰种铁皮石斛中的黄酮类成分,并探究不同生长年限对黄酮类成分积累的影响。方法:用Kromasil 100-5 C_(18)色谱柱(250 mm×4.6 mm,5μm),以乙腈-甲醇(v:v=1:1)-0.01 mol/L乙酸铵溶液为流动相进行梯度洗脱,质谱使用ESI... 详细信息

目的:分析广西铁皮兰种铁皮石斛中的黄酮类成分,并探究不同生长年限对黄酮类成分积累的影响。方法:用Kromasil 100-5 C_(18)色谱柱(250 mm×4.6 mm,5μm),以乙腈-甲醇(v:v=1:1)-0.01 mol/L乙酸铵溶液为流动相进行梯度洗脱,质谱使用ESI离子源,在负离子模式下采集数据;采用HPLC法建立25批广西铁皮石斛HPLC特征图谱,并运用主成分分析和聚类分析探讨不同生长年限对广西铁皮石斛黄酮类成分积累的影响。结果:通过HPLC-ESI-MS^(n)技术,从广西铁皮石斛中鉴定了19个黄酮类成分,涵盖了黄酮碳苷(9个)、黄酮醇氧苷(4个)、酰化黄酮碳苷(2个)、酰化黄酮醇氧苷(3个)及二氢黄酮(1个)。构建了广西铁皮石斛黄酮类成分特征图谱,并指认了9个共有峰;基于聚类与主成分分析,将25份样品按生长年限及杆色(绿杆1~3年、绿杆3~5年、红杆1~3年、红杆3~5年)划分为四类。此外,黄酮类特征峰峰面积随着生长年限的增长而增长;在1~3年生长年限时,‘红杆’与‘绿杆’间黄酮含量无显著差异;但3~5年,红杆样品中新西兰牡荆苷Ⅰ、Ⅲ、佛莱心苷及特定峰(峰8、峰9)含量显著高于绿杆。结论:本研究通过质谱分析结合化学模式识别,揭示了广西铁皮石斛黄酮类成分的共有特征,并强调了生长年限对黄酮类成分积累的关键作用。特别指出,生长至3~5年,‘红杆’样品中黄酮类成分含量显著高于‘绿杆’,此发现为铁皮石斛的药理活性探索、应用开发、种质资源评价及采收策略提供了坚实的理论基础。

关键词：广西铁皮兰种黄酮类成分化学模式识别品种生长年限

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上海某混凝土制品公司土壤污染状况初步调查研究

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广东化工 2024年第14期51卷 131-133页

作者：崔铭昊王樟华蒋玲玲上海华闵环境股份有限公司土壤部上海200000

以上海某混凝土制品公司为研究对象开展了土壤污染状况调查以明确地块土壤环境状况,为地块的后续开发利用提供相应的环境管理依据。通过第一阶段调查,识别出地块历史上存在农田、码头堆场、混凝土制品公司,且存在疑似污染区域。因而进... 详细信息

以上海某混凝土制品公司为研究对象开展了土壤污染状况调查以明确地块土壤环境状况,为地块的后续开发利用提供相应的环境管理依据。通过第一阶段调查,识别出地块历史上存在农田、码头堆场、混凝土制品公司,且存在疑似污染区域。因而进行第二阶段土壤污染状况调查,检测结果表明地块内土壤和地下水的环境质量均满足相关标准要求,可作为港口码头用地开发利用,无需开展下一阶段详细调查工作。

关键词：混凝土制品公司污染状况调查疑似污染区域土壤地下水

Enhanced Terahertz Fingerprint Detection beyond Refractive Index Sensing in a Periodic Silicon Waveguide Cavity

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Journal of Electronic Science and Technology 2018年第2期16卷 105-109页

作者： Bei Zhu zhanghua Han College of Mechanical and Electrical Engineering China Jiliang UniversityHangzhou 310018 Advanced Launching Co-Innovation Center Naniing University of Science and TechnologyNanjing 210094

Resonance shifting due to refractive index changes is used quite often in terahertz sensing, but it does not show the advantages of substance identification of terahertz technology. Different from that approach, we explored the use of a cavity to enhance the sensitivity of terahertz sensing while retaining the original capability of substance identification. The defect mode of a one-dimensional photonic crystal cavity composed of periodic holes etched into a silicon wire wavegnide was investigated for this purpose. The resonance of the defect mode was designed to match one characteristic absorption frequency of the sample. Due to the high dependence of the defect mode transmission on the material loss, the transmission sensitivity to the quantity of target was amplified significantly. The detection of alactose was used as an example, which demonstrates steady detection with its thickness of a few microns.

关键词： Detection photonic crystal terahertz sensing waveguide