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Evaluating the thermal environment of urban land surfaces in Yakutsk,a city located in a region of continuous permafrost

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Advances in Climate Change Research 2024年第1期15卷 113-123页

作者： Xiang-Long LI Ze ZHANG Jin-Xin LU Anatoli BROUCHKOV qing-kai yan Qi-Hao YU Sheng-Rong ZHANG Andrey MELNIKOV School of Civil Engineering and Transportation Institute of Cold Regions Science and EngineeringPermafrost InstituteNortheast Forestry UniversityHarbin150040China China Railway qinghai-Tibet Group Company Xining 810000China Department of Geocryology Faculty of GeologyLomonosov Moscow State UniversityMoscow 119234Russian Federation State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco Envi ronment and Re sourcesChinese Academy of SciencesLanzhou 730000China Melnikov Permafrost Institute Siberian BranchRussian Academy of ScienceYakutsk 677010Russian Federation

Rapid urbanization has led to changes in the urban land surface thermal ***,there are still much unknown about the urban land surface thermal conditions in permafrost *** is a unique geological environment,changes in the urban land surface thermal environment may trigger geological disasters caused by permafrost *** study utilized remote sensing data and geographic de-tectors to identify the dynamic changes in land surface temperature(LST)and land use/land cover(LU/LC)in Yakutsk,as well as the potential factors contributing to LST *** 1992 and 2020,the built-up area in Yakutsk increased by 36%,and the annual average LST in Yakutsk has risen by 6.67℃,accompanied by an expansion of high-temperature *** ongoing greening efforts,rapid urbanization poses a threat to these green *** in the normalized difference built-up index(NDBI)and land use transfer(LDT)were identified as the primary drivers of urban LST *** integrating geographic detector technology and artificial neural network models,we optimized the selection of input factors in the prediction model and used it to explore the future changes in LST in *** average LST in Yakutsk is expected to reach 23.4℃ and 25.1℃ in 2030 and 2040,respectively,with a further increase in high-temperature *** study provides a reference for ecological,hydrological,and geological assessments of cities in permafrost regions.

关键词： Remote sensing Land surface temperature Land use/Land cover Permafrost Yakutsk

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Electronegativity-assisted optimized electronic structure of functionalized-Pt catalysts for boosting oxygen reduction kinetics

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Rare Metals 2024年第5期43卷 1965-1976页

作者： Jin Long kai-Wen Zhuang Wei Liao yan An Bin Wang Chen-Zhong Wu Jian-Xin Cao qing Wang Jun-Song Chen qing-Mei Wang Guizhou University Key Laboratory of Green Chemical and Clean Energy Technology School of Chemistry and Chemical EngineeringGuizhou UniversityGuiyang 550025China Guizhou University Engineering Research Center of Effcient Utilization for Industrial Waste Guizhou UniversityGuiyang 550025China Institute of Dual-Carbon and New Energy Technology Innovation and Development of Guizhou Province Guiyang 550025China Department of Dermatology West China HospitalSichuan UniversityChengdu610041China Institute for Catalysis Hokkaido UniversitySapporo 001-0021Japan School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731China Interdisciplinary Materials Research Center Institute for Advanced StudyChengdu UniversityChengdu 610106China

Opportunity to harmonize aspects of oxygen reduction reaction(ORR)performance and structure,and morphology,as well as composition,is urgent for the commercialization of proton exchange membrane fuel ***,we demonstrate the design and synthesis of a functionalized-supported-Pt catalyst(Pt@HNC)featuring a hollow nitrogen-modified dodecahedral carbon substrate obtained by a stress-induced-shrink tailoring *** as-obtained Pt@HNC catalyst possesses enhanced ORR per-formance,in particular with half-wave potential,mass activity(MA)and specific activity,which greatly exceed the commercial Pt/*** density functional theory(DFT)calculations further confirmed that the charge redistribution induced by the electronegativity differences improved the electron interaction between Pt and HNC *** optimized electronic structure of Pt weakens the reaction energy barrier on the Pt@HNC surface and adsorption of^(*)OH species,thus cooperatively improving the intrinsic activity toward ***,our work indeed provides a guide for the future design of functional nanomaterials in the field of catalysts and clean energy.

关键词： Proton exchange membrane fuel cell(PEMFC) Oxygen reduction catalysis Supported Pt-based catalyst Stability

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Corrosion behavior of Gd_(2)Zr_(2)O_(7)thermal barrier coatings under Fe-containing environmental sediment attack

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Journal of Advanced Ceramics 2024年第4期13卷 447-462页

作者： Lei Guo yanyan Li kai yan School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Advanced Joining Technology Key Lab of Advanced Ceramics and Machining Technology of Ministry of EducationTianjin 300072China Key Laboratory of Special Equipment Safety and Energy-saving for State Market Regulation China Special Equipment Inspection&Research InstituteBeijing 100029China

Environmental sediments mainly consisting of CaO–MgO–Al_(2)O_(3)–SiO_(2)(CMAS)corrosion are a serious threat to thermal barrier coatings(TBCs),in which Fe element is usually ***_(2)Zr_(2)O_(7)TBCs are famous for their excellent CMAS *** this study,the characteristics of Fe-containing environmental sediments(CMAS-Fe)and their corrosiveness to Gd_(2)Zr_(2)O_(7)coatings were *** types of CMAS-Fe glass with different Fe contents were *** melting points were measured to be 1322–1344℃,and the high-temperature viscosity showed a decreasing trend with increasing Fe *** corrosion behavior of four types of CMAS-Fe to Gd_(2)Zr_(2)O_(7)coatings at 1350℃was *** the initial corrosion stage(0.1 h),anorthite was precipitated in CMAS-Fe with a high Ca:Si ratio,while Fe-garnet was formed in the melt with the highest Fe *** the corrosion time resulted in the formation of a reaction layer,which exhibited an interpenetrating network composed of Gd-oxyapatite,ZrO_(2),and residual *** spinel was precipitated within the reaction *** 1 h or even longer time,the reaction layers tended to be stable and compact,which had comparable hardness and fracture toughness to those of Gd_(2)Zr_(2)O_(7)*** the cyclic CMAS-Fe attack,the residual CMAS-Fe in the interpenetrating network provided a pathway for the redeposited CMAS-Fe infiltration,resulting in the continuous growth of the reaction *** a result,the Gd_(2)Zr_(2)O_(7)coatings had a large consumption in the thickness,degrading the coating ***,the Gd_(2)Zr_(2)O_(7)coatings exhibit unsatisfactory corrosion resistance to CMAS-Fe attack.

关键词： thermal barrier coatings(TBCs) Gd_(2)Zr_(2)O_(7) Fe-containing CaO-MgO-Al2O3-SiO_(2)(CMAS) corrosion resistance reaction layer

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Recent geomagnetic storms observed by Macao Science Satellite-1

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Earth and Planetary Physics 2024年第4期8卷 565-569页

作者： qing yan HongBo Yao Macao Institute of Space Technology and Application Macao University of Science and TechnologyMacao 999078China

Geomagnetic storms are rapid disturbances of the Earth’s *** are related to many geophysical phenomena and have large influences on human *** and studying geomagnetic storms is thus of great significance to both scientific research and geomagnetic hazards *** Macao Science Satellite-1(MSS-1)project includes two high-precision Chinese geomagnetic satellites successfully launched on May 21,*** main purpose of MSS-1 is to accurately measure the Earth’s magnetic ***,we analyze early MSS-1 geomagnetic field measurements and report observations of two recent geomagnetic storms that occurred on March 24,2024 and May 11,*** also calculate the related geoelectric fields as an initial step towards a quantitative assessment of geomagnetic hazards.

关键词： Macao Science Satellite-1 geomagnetic storms satellite magnetics electromagnetic induction geoelectric fields

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Beyond 1,4-addition of in-situ generated(aza-)quinone methides and indole imine methides

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Chinese Chemical Letters 2024年第7期35卷 35-53页

作者： yan-Li Li Zhi-Ming Li kai-kai Wang Xiao-Long He Medical College Xinxiang UniversityXinxiang 453000China School of Pharmacy Xinxiang UniversityXinxiang 453000China School of Food and Bioengineering Xihua UniversityChengdu 610039China

The conjugate addition of in-situ generated(aza-)quinone methides(QMs)and indole imine methides(IIMs)emerged as a powerful protocol to access densely functionalized benzenes and *** alcohols,aminobenzhydryl alcohols,and varied indolylmethanols served as most effective precursors for the in-situ generation of such reactive species under acid *** relevant propargylic alcohol has proven to be an elegant precursor to generate the propargylic-QMs and-IIMs via the acid promoted dehydration process,thus enabling diverse challenging remote activation to proceed conjugate1,6-and 1,***,the heteroarene has proven to be workable to transfer the LUMO of the p-QMs and 2-IIMs,thus inducing the remote nucleophilic dearomative *** conjugate additions of(aza-)p-QMs and varied IIMs has made significant contribution in the field of remote activation chemistry in past *** review summarizes the latest advances of the remote conjugate additions of the in-situ generated QMs and IIMs.

关键词： Conjugate addition QMs IIMs LUMO Remote activation Dearomative addition

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Spherical Confinement Generates Entropic Force to Accelerate Polymer Chain Detachment

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Chinese Journal of Polymer Science 2024年第3期42卷 407-416,I0010页

作者： Yu-Shan Zheng Jian-Ping Zhou yan Xu kai Li Mechanical Engineering Xinjiang UniversityUrumqi 830002China

To understand the dynamic process of polymer detachment, it is necessary to determine the mean detachment time of a single breakable link, which is modeled as a spring. Normally, this time can be viewed as the escape of a Brownian particle from the potential well of the spring. However, as the free dangling length of the polymer chain increases, the conformational entropy of the chain is affected by geometric confinement. It means that the wall exerts a repulsive force on the chain, resulting in accelerated link detachment from a macroscopic perspective. In this work, we investigate the effect of entropy on the detachment rate in the case where the substrate is spherical. We demonstrate that spherical confinement accelerates chain detachment both inside and outside the sphere. An analytical expression for the mean detachment time of breakable links is given, which includes an additional pre-factor that is related to the partition function. Additionally, we analyze the expressions for entropic forces inside the sphere, outside the sphere, and on a flat wall, comparing their magnitudes to explain the difference in mean detachment time.

关键词： Polymer detachment Breakable link Entropic force Mean first passage time

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Flexible and Stretchable Electrodes for In Vivo Electrophysiological and Electrochemical Monitoring

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Chinese Journal of Chemistry 2024年第13期42卷 1523-1545页

作者： kai-kai Sheng Yi-Fei Lu Wen-Ting Fan yan-Ling Liu College of Chemistry and Molecular Sciences Wuhan University WuhanHubei 430072China Core Facilty of Wuhan University WuhanHubei 430072China

In vivo monitoring of bioelectrical and biochemical signals with implanted electrodes has received great interest over the past ***,this faces huge challenges because of the severe mechanical mismatch between conventional rigid electrodes and soft biological *** recent years,the emergence of flexible and stretchable electrodes offers seamless and conformable biological-electronic interfaces and has demonstrated significant advantages for in vivo electrochemical and electrophysiological *** review first summarizes the strategies for electrode fabrication from the point of substrate and conductive ***,recent progress in electrode functionalization for improved performance is ***,the advances of flexible and stretchable electrodes in exploring bioelectrical and biochemical signals are ***,we present some challenges and perspectives ranging from electrode fabrication to application.

关键词： Flexible electrodes Conductive materials Stretchable structures Electrode functionalization In vivo monitoring Biochemical signals Bioelectrical signals

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Numerical simulation on directional solidification and heat treatment processes of turbine blades

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China Foundry 2024年第5期21卷 476-490页

作者： Ye-yuan Hu Ju-huai Ma qing-yan Xu School of Materials Science and Engineering Tsinghua UniversityKey Laboratory for Advanced Materials Processing TechnologyMinistry of EducationBeijing 100084China

Study on turbine blades is crucial due to their critical role in ensuring the efficient and reliable operation of aircraft ***-based single crystal superalloys are extensively used in the hot manufacturing of turbine blades due to their exceptional high-temperature mechanical *** hot manufacturing of single crystal blades involves directional solidification and heat *** manufacturing of these blades is time-consuming,capital-intensive,and often insufficient to meet industrial *** simulation techniques have gained widespread acceptance in blade manufacturing research due to their low energy consumption,high efficiency,and rapid turnaround *** article introduces the modeling and simulation of hot manufacturing in single crystal *** discussion outlines the prevalent mathematical models employed in numerical simulations related to blade hot *** encapsulates the advancements in research concerning macro to micro-level numerical simulation techniques for directional solidification and heat treatment ***,potential future trajectories for the numerical simulation of single crystal blade hot manufacturing are also discussed.

关键词： single crystal blades Ni-based superalloy directional solidification heat treatment numerical simulation

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Cut-off value of glycated hemoglobin A1c for detecting diabetic retinopathy in the Chinese population

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World Journal of Diabetes 2024年第7期15卷 1531-1536页

作者： yan Wen qing Wang Department of Endocrinology China-Japan Union Hospital of Jilin UniversityChangchun 130033Jilin ProvinceChina

BACKGROUND Glycated hemoglobin A1c(HbA1c)is considered the most suitable for diabetes mellitus diagnosis due to its accuracy and ***,the effect of HbA1c on diabetic retinopathy(DR)in the Han and Korean populations in Jilin,China,remains *** To determine the best cut-off of HbA1c for diagnosing DR among the *** This cross-sectional study included 1933 participants from the yanbian area of Jilin Province,*** investigators employed a questionnaire-based survey,physical examination,laboratory tests,and fundus photography for the *** best cut-off value for HbA1c was established via the receiver operating characteristic *** factors associated with HbA1c-associated risk factors were determined via linear *** The analysis included 887 eligible Chinese Han and Korean participants,591 of whom were assigned randomly to the training set and 296 to the validation *** prevalence of DR was 3.27% in the total ***1c of 6.2% was the best cut-off value in the training set,while it was 5.9% in the validation *** both Chinese Han and Korean populations,an HbA1c level of 6.2% was the best cut-off *** optimal cut-off values of fasting blood glucose(FBG)≥7 mmol/L and<7 mmol/L were 8.1% and 6.2% respectively in Han populations,while those in Korean populations were 6.9%and 5.3%,***,body mass index,and FBG were determined as the risk factors impacting HbA1c *** HbA1c may serve as a useful diagnostic indicator for *** HbA1c level of 6.2% may be an appropriate cut-off value for DR detection in the Chinese population.

关键词： Diabetic retinopathy Glycated hemoglobin A1c Cut-off value Age Body mass index Fasting blood glucose

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Model Parameters Identification and Backstepping Control of Lower Limb Exoskeleton Based on Enhanced Whale Algorithm

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 100-114页

作者： yan Shi Jiange Kou Zhenlei Chen Yixuan Wang qing Guo School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China School of Aeronautics and Astronautics University of Electronic Science and Technology of ChinaChengdu 611731China

Exoskeletons generally require accurate dynamic models to design the model-based controller conveniently under the human-robot interaction ***,due to unknown model parameters such as the mass,moment of inertia and mechanical size,the dynamic model of exoskeletons is difficult to ***,an enhanced whale optimization algorithm(EWOA)is proposed to identify the exoskeleton model ***,the periodic excitation trajectories are designed by finite Fourier series to input the desired position demand of exoskeletons with mechanical physical *** a backstepping controller based on the identified model is adopted to improve the human-robot wearable comfortable performance under cooperative ***,the proposed Model parameters identification and control are verified by a two-DOF exoskeletons *** knee joint motion achieves a steady-state response after 0.5 ***,the position error of hip joint response is less than 0.03 rad after 0.9 *** addition,the steady-state human-robot interaction torque of the two joints is constrained within 15 N·*** research proposes a whale optimization algorithm to optimize the excitation trajectory and identify model ***,an enhanced mutation strategy is adopted to avoid whale evolution’s unsatisfactory local optimal value.

关键词： Parameter identification Enhanced whale optimization algorithm(EWOA) Backstepping Human-robot interaction Lower limb exoskeleton

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