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Thermal stability enhancement and prediction by ANN model

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Energy and AI 2024年第2期16卷 125-136页

作者： Ziyu Liu xiaoyi Yang School of Energy and Power Engineering Energy and Environment International CenterBeihang UniversityBeijing100191China School of Aeronautic Science and Engineering Beihang UniversityBeijing100191China

Supersonic aircraft requires thermal endurance of aviation fuel in the process of cooling engine and aircraft. As the composition of petroleum-based jet fuel (RP-3) is confined by crude oil and refining process, sustainable alternative jet fuel with green house gas reduction become to undertake the composition optimization for improving thermal stability. For designing aviation fuel with robust thermal stability and the detail understanding of thermal stability mechanism, RP-3, Fischer–Tropsch fuel, and additives with cyclic structure for absorbing free radical, were investigated thermal stability by modifying different blend ratios under different conditions. Thermal endurance degree was assessed by chroma and deposition tendency. FT blend with cyclic hydrocarbon can improve thermal endurance degree. In compliance with individual optimized blend ratio, the contribution follows methyl cyclopentane > decalin > methyl cyclohexane > tetralin > n-propyl-benzene > 1.2,4 trimethyl-benzene. The appropriate blend ratio could undertake hydrogen donors for terminating the propagation of oxygen-carrying radical, but hydrocarbons with cyclic structure could enhance deposition tendency. Methyl cyclopentane and its oxidation derivatives take the roles of solvent by anti-polymerization and hydrogen donor by opening cyclic structure in the thermal endurance process, and thus lead to a wide range of blend ratio for improving significantly thermal stability. β-scission leading to C–C bond cleavage is the major reaction at the early decomposition stage, which resulted in most abundant derivatives plus C2. The effects of additives on thermal stability are complex and nonlinear on the tendency of thermal deposits and thermal endurance degree, and thus the appropriate ANN-thermal stability model has been trained based on the experiment data and can achieve above 0.995 correlation coefficient. ANN - thermal stability model can predict not only the content of derivatives including ester, o

关键词： Sustainable jet fuel Thermal stability ANN Thermal endurance Fuel pyrolysis

Hydrothermal liquefaction of biomass for jet fuel precursors:A review

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Chinese Chemical Letters 2024年第8期35卷 36-49页

作者： Shengfei Dong Ziyu Liu xiaoyi Yang School of Energy and Power Engineering Energy and Environment International CentreBeihang UniversityBeijing 100191China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China

Climate change is an important issue facing the world today and carbon reduction has become the fo-cus of attention for all *** bio-fuels are an important means to achieve carbon emis-sion *** production of jet fuel precursors from biomass by hydrothermal liquefaction(HTL)has received a lot of attention due to its mild conditions and environmental *** biomass and algal biomass are considered as the second and the third generation biomasses as promising raw materials for alternative fuel *** them,lignocellulosic biomass has been extensively studied due to its wide range of sources and can be divided into one-step HTL and stepwise HTL accord-ing to the process *** biomass has been extensively studied experimentally due to its short growth cycle and the fact that it can sequester large amounts of carbon without taking up arable *** this paper,the feedstock composition of different biomasses is reviewed for the HTL of biomass.A detailed review of the process characteristics,reaction pathways and influencing factors for the HTL pro-duction of jet fuel precursors from lignocellulosic biomass and algal biomass is also *** references are provided for further process optimization and bio-crude quality upgrading.

关键词： Hydrothermal liquefaction(HTL) Lignocellulosic biomass Microalgae Bio-crude Jet fuel precursors

Dynamic response of buildings under debris flow impact

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Journal of Mountain Science 2024年第5期21卷 1581-1597页

作者： LIU Huan FAN xiaoyi TIAN Shujun DENG Xin School of Mechanical and Electrical Engineering Southwest Petroleum UniversityChengdu 610500China School of Civil Engineering and Geomatics Southwest Petroleum UniversityChengdu 610500China Housing and Urban-Rural Development Bureau of Mingshan District Ya’an 625100China Engineering Safety Assessment and Protection Research Southwest Petroleum UniversityChengdu 610500China School of Civil Engineering and Architecture Southwest University of Science and TechnologyMianyang 621010China

This study employs the smoothed particle hydrodynamics–finite element method(SPH–FEM) coupling numerical method to investigate the impact of debris flow on reinforced concrete(RC)-frame buildings. The methodology considers the variables of debris flow depth and velocity and introduces the intensity index IDV(IDV = DV) to evaluate three different levels of debris flow impact intensity. The primary focus of this study is to investigate the dynamic response and failure mechanism of RC-frame buildings under debris flow impact, including structural failure patterns, impact force and column displacement. The results show that under a highintensity impact, a gradual collapse process of the RCframe building can be observed, and the damage mode of the frame column reflects shear failure or plastic hinge failure mechanism. First, the longitudinal infill walls are damaged owing to their low out-of-plane flexural capacity;the critical failure intensity index IDV value is approximately 7.5 m2/s. The structure cannot withstand debris flows with an intensity index IDV greater than 1. m2/s, and it is recommended that the peak impact force should not exceed 21.0 k N. The impact damage ability of debris flow on buildings mostly originates from the impact force of the frontal debris flow, with the impact force of the debris flow body being approximately 42% lower than that of the debris flow head. Finally, a five-level classification system for evaluating the damage status of buildings is proposed based on the numerical simulation and investigation results of the disaster site.

关键词： SPH–FEM method Debris flow Buildings The intensity index Dynamic response

Energy flexibility and resilience analysis of demand-side energy efficiency measures within existing residential houses during cold wave event

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Building Simulation 2024年第7期17卷 1043-1063页

作者： xiaoyi Zhang Fu Xiao Yanxue Li Yi Ran Weijun Gao Innovation Institute for Sustainable Maritime Architecture Research and Technology Qingdao University of TechnologyQingdaoChina Department of Building Environment and Energy Engineering The Hong Kong Polytechnic UniversityHong KongChina Faculty of Environmental Engineering The Universityof KitakyushuKitakyushuJapan

Using the behind-meter data,this study applied a comparison and optimization-based framework to evaluate the energy flexibility and resilience of distributed energy resources within existing houses during cold wave *** analysis demonstrates the effectiveness of high envelope insulation level in improving energy resilience,identifies impacts of distributed energy resources on variations of household electricity ***,a 1..6%reduction in the median value of the normalized load of building group with low U-values,implementations of cogeneration system effectively suppressed variations of electricity *** energy performances of on-site generators are evaluated based on high resolution data,energy flexibility of domestic hot water and thermostatically controlled loads were investigated through built demand response *** reveal that electrifying hot water demand offers additional power flexibility,the integration of fuel cell cogeneration system has proven to be an efficient energy resource,enabling on-site generation of both electricity and hot water,substantially reducing grid *** extreme cold event resulted in significant spikes in space heating power *** optimization results demonstrate that reducing the indoor setpoint temperature effectively decreases daily power consumption by approximately 5.0%per degree *** findings help acquire better understanding of interconnections between energy efficiency and resilience of residential energy-efficient measures.

关键词： system modeling energy efficiency energy resilience cold wave thermal comfort

Eutectogel-based self-powered wearable sensor for health monitoring in harsh environments

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Nano Research 2024年第6期17卷 5559-5568页

作者： Junpeng Wu Xinru Teng Lu Liu Hongzhi Cui xiaoyi Li College of Materials Science and Engineering Ocean University of ChinaQingdao 266100China Key Lab for Special Functional Materials of Ministry of Education School of Materials Science and EngineeringHenan UniversityKaifeng 475004China

Triboelectric nanogenerators(TENG)have emerged as a highly promising energy harvesting technology,attracting significant attention in recent years for their broad ***-based TENGs,with superior stretchability and sensitivity,have been widely reported as wearable ***,the traditional hydrogel-based TENGs suffer from freezing at low temperatures and drying at high temperatures,resulting in *** this study,we introduce an anti-freezing eutectogel,which uses a deep eutectic solvent(DES),to improve the stability and electrical conductivity of TENGs in harsh environmental *** eutectogel-based TENG(E-TENG)produces an open-circuit voltage of 776 V,a short-circuit current of 1.54μA,and a maximum peak power of 1.1.***,the E-TENG exhibits exceptional mechanical properties with an elongation at a break of 476%under ***,it maintains impressive performances across a wide temperature range from−1. to 60℃,with conductivities of 2.1. S/m at−1.℃and 1.75 S/m at−1.℃.Based on the excellent weight stability of the E-TENG sensor,motion sensing can be achieved in the air,and even ***,the versatility of the E-TENG can serve as a wearable sensor,by integrating it with Bluetooth *** self-powered E-TENG can monitor various human motion signals in real-time and send the health signals directly to mobile *** research paves a new road for the applications of TENGs in harsh environments,offering wireless flexible sensors with real-time health signal monitoring capabilities.

关键词： triboelectric nanogenerators self-powered harsh environment health monitoring Eutectogel

Biocompatible Biphasic Iontronics Enable Neuron-Like Ionic Signal Transmission

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Research 2024年第3期2024卷 795-796页

作者： xiaoyi Wang Aleksandar P.Ivanov Joshua B.Edel Department of Chemistry Imperial College LondonMolecular Sciences Research HubLondon W12 OBZUK

Biocompatible connections between external artificial devices and living organisms show promise for future neuroprosthetics and *** study in Science by Zhao and colleagues introduces a cascade-heterogated biphasic gel(HBG)iontronic device,which facilitates electronic-to-multi-ionic signal transduction for abiotic–biotic *** by neuron signaling,the HBG device demonstrated its biocompatibility by regulating neural activity in biological tissue,paving the way for wearable and implantable devices,including brain–computer interfaces.

关键词： asi Signal Neuron

On the longitudinal shifts of the Agulhas retroflection point

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Acta Oceanologica Sinica 2024年第5期43卷 16-29页

作者： Weiwei Zhang xiaoyi Yang Wei Zhuang Xiaohai Yan State Key Laboratory of Marine Environmental Science College of Ocean and Earth SciencesXiamen UniversityXiamen 361002China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China Center for Remote Sensing College of EarthOcean and EnvironmentUniversity of DelawareNewarkDE 19716USA Joint Center for Remote Sensing University of Delaware-Xiamen UniversityNewarkDE 19716USA and Xiamen 361002China

The Agulhas system is the strongest western boundary current system in the Southern Hemisphere and plays an important role in modulating the Indian-to-Atlantic Ocean water exchange by the Agulhas *** is difficult to measure in situ transport of the Agulhas leakage as well as the Agulhas retroflection position due to their intermittent *** this study,an innovative kinematic algorithm was designed and applied to the gridded altimeter observational data,to ascertain the longitudinal position of Agulhas retroflection,the stability of Agulhas jet stream,as well as its *** results show that the east-west shift of retroflection is related neither to the strength of Agulhas current nor to its *** analysis uncovers the connection between the westward extension of Agulhas jet stream and an anomalous cyclonic circulation at its northern side,which is likely attributed to the local wind stress curl *** confirm the effect of local wind forcing on the east-west shift of retroflection,numerical sensitivity experiments were *** results show that the local wind stress can induce a similar longitudinal shift of the retroflection as altimetry *** statistical and case study indicates that whether an Agulhas ring can continuously migrate westward to the Atlantic Ocean or re-merge into the main flow depends on the retroflection ***,the westward retroflection may contribute to a stronger Agulhas leakage than the eastward retroflection.

关键词： Agulhas system Agulhas leakage retroflection position local wind stress curl

黄芩中黄芩苷的亚临界水提取及高效液相色谱分析

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色谱 2004年第1期22卷 44-47页

作者：徐志宏钱广生刘三康李章万陈筱义四川大学华西药学院四川成都610041 成都地奥制药集团有限公司四川成都610041

建立了黄芩药材中黄芩苷的亚临界水提取高效液相色谱测定方法。分别考察了温度、压力、提取时间、提取物颗粒度、溶剂比等因素对提取量的影响,并与有机溶剂提取法比较。结果表明,当两者具有相同的提取效果时,亚临界水提取法的提取时间... 详细信息

建立了黄芩药材中黄芩苷的亚临界水提取高效液相色谱测定方法。分别考察了温度、压力、提取时间、提取物颗粒度、溶剂比等因素对提取量的影响,并与有机溶剂提取法比较。结果表明,当两者具有相同的提取效果时,亚临界水提取法的提取时间及提取溶剂的消耗量大大减少,避免了使用有机溶剂造成的污染。黄芩苷提取最佳条件为:样品颗粒度80～1.0目,溶剂比0 2mL/mg,5MPa,1.0℃保持1.min。并通过提取高效液相色谱联机分析实现了对提取物的实时监测。该技术有望成为从中药材中提取脂溶性成分的有效方法。

关键词：黄芩黄芩苷亚临界水提取高效液相色谱分析实时监测脂溶性成分中药材

Quantifying Contribution of Recycled Moisture to Precipitation in Temperate Glacier Region,Southeastern Tibetan Plateau,China

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Chinese Geographical Science 2024年第4期34卷 764-776页

作者： MA Yanwei PU Tao SHI xiaoyi MA Xinggang YU Hongmei College of Geography and Environmental Sciences Zhejiang Normal UniversityJinhua 321004China National Field Science Observation and Research Station of Yulong Snow Mountain Cryosphere and Sustainable Development Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China State Key Laboratory of Cryospheric Sciences Northwest Institute of Eco-environment and ResourcesChinese Academy of SciencesLanzhou 730000China

Recycled moisture is an important indicator of the renewal capacity of regional water *** to the existence of Yulong Snow Mountain,Lijiang in Yunnan Province,southeast of the Qinghai-Tibet Plateau,China,is the closest ocean glacier area to the equator in *** precipitation samples were collected from 201. to 201. in Lijiang to quantify the effect of sub-cloud evaporation and recycled moisture on precipitation combined with the d-excess model during monsoon and non-monsoon *** results indicated that the d-excess values of precipitation fluctuated between–35.6‰and 1..0‰,with an arithmetic mean of 3.5‰.The local meteoric water line(LMWL)wasδD=7.91.^(1.)O+2.50,with a slope slightly lower than the global meteoric water line(GMWL).Subcloud evaporation was higher during the non-monsoon season than during the monsoon *** tended to peak in March and was primarily influenced by the relative *** source of the water vapour affected the proportion of recycled *** to the results of the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model,the main sources of water vapour in Lijiang area during the monsoon period were the southwest and southeast *** the non-monsoon period,water vapour was transported by a southwesterly *** recycled moisture in Lijiang area between March and October 201. was 1..62%.Large variations were observed between the monsoon and non-monsoon seasons,with values of 5.48%and 25.65%,*** differences were primarily attributed to variations in the advection of water *** recycled moisture has played a supplementary role in the precipitation of Lijiang area.

关键词： recycled moisture stable isotope precipitation d-excess Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model southeastern Tibetan Plateau China