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Simulation of roof snow loads based on a multi-layer snowmelt model:Impact of building heat transfer

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Building Simulation 2024年第6期17卷 907-932页

作者： Xuanyi Zhou heng chen Yue Wu Tiange Zhang State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai200092China

To investigate the impact of building heat transfer on roof snow loads,roof snow loads and snow load thermal coefficients from 61 Chinese sites over a period of 50 years are simulated based on basic meteorological data such as temperature,humidity,wind speed,and precipitation,and a multi-layer snowmelt model considering the building heat ***,the accuracy of the multi-layer snowmelt model is validated using the data of observed ground snow load and roof snow melting *** relationship between meteorological conditions,snow cover characteristics,and thermal coefficients of snow loads in three representative sites is then ***,the characteristics of thermal coefficients in each zone are analyzed by combining them with the statistical results of meteorological data from 1960 to 2010,and the equations of thermal coefficients in different zones on indoor temperatures and roof heat transfer coefficients are fitted ***,the equations in this paper are compared with the thermal coefficients in the main snow load *** results indicate that the snowmelt model using basic meteorological data can effectively provide samples of roof snow *** the cold zone where the snow cover lasts for a long time and does not melt easily,the thermal coefficients of the snow loads on the heating buildings are lower than those in the warm zone due to the long-term influence of the heat from inside the *** coefficients are negatively correlated with indoor temperatures and roof heat transfer *** the indoor temperature is too low or the roof insulation is good,the roof snow load may exceed the ground snow *** thermal coefficients for heated buildings in the main snow load codes are more conservative than those calculated in this paper,and the thermal coefficients for buildings with lower indoor temperatures tend to be smaller.

关键词： snowmelt model roof snow load building heat transfer thermal coefficient load code

Preparation,optical properties and energy transfer of SrLaAlO4:Dy3+,Eu3+

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Journal of Rare Earths 2024年第11期42卷 2058-2067页

作者： Wei chen heng Zhang Desheng Zhu School of Physic and Optoelectronic Engineering Yangtze University

A series of Dy3+/Eu3+single doped and co-doped SrLaAlO4phosphors was synthesized by the traditional high-temperature solid-state method,and their structure,morphology and optical properties were *** X-ray diffraction（XRD） shows a small amount of doping with Dy3+and Eu3+does not change the crystal structure of the matrix SrLaAlO4and the best synthesis temperature is 1450℃.The scanning electron microscopy（SEM） indicates the particle size directly ranges from 1 to 5μm roughly and the energy dispersive spectroscopy（EDS） patterns show that SrLaAlO4:Dy3+phosphor and SrLaAlO4:Dy3+,Eu3+phosphor were successfully ***4:Dy3+phosphor can be effectively excited by near-ultraviolet light,producing two strong emission lights at 483 nm（blue light） and 579 nm（yellow light）,presenting a cold white light;SrLaAlO4:Eu3+phosphor can be effectively excited by nearultraviolet light,producing red lights at 622 nm;the characteristic emission peaks of Dy3+and Eu3+can be shown simultaneously under the same excitation wavelength in SrLaAlO4:Dy3+, Eu3+*** changing the relative doping concentration ratio of Dy3+and Eu3+,the modulation of SrLaAlO4:Dy3+,Eu3+phosphor from cold white to warm white light can be *** addition,the study of the luminescent mechanism and lifetime shows that there is energy transfer between Dy3+and Eu3+in SrLaAlO4:Dy3+,Eu3+phosphor.

关键词： Energy transfer High-temperature solid-phase method Luminescence properties Rare earths SrLaAlO4: Dy3+, Eu3+ White phosphor

A theoretical model for impact protection of flexible polymer material

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Theoretical & Applied Mechanics Letters 2024年第3期14卷 217-226页

作者： Huifeng Xi Hui Pan Song chen heng Xiao MOE Key Lab of Disaster Forecast and Control in Engineering School of Machanics and Construction EngineeringJinan UniversityGuangzhou 510632China Doctor Workstation of Xuwen County Guangdong Hydropower Energy Co. Ltd.Xuwen 524100China

The relationship between the protective performance of flexible polymer material and material parameters(elasticmodulus,viscosity coefficient)is explored,an impact collision motion equation between two bodies is establishedfrom the viscoelastic material constitutive,and the relationship between the kinematic response and the materialparameters is *** on the Kelvin constitutive model,a theoretical model for impact between the pro-tective body and the protected body is established,then the dynamic response is *** feasibility of themodel was verified by drop hammer experiment,and the material parameters(elastic modulus,viscosity coeffi-cient)were obtained by *** model is discretized and the relationship between local impact response andmaterial parameters is *** discussion results on the relationship between the impact response and theprotective material performance indicate that adjusting the elastic modulus,viscosity coefficient,and thicknessof the protective material can effectively improve protective effect.

关键词： Flexible polymer material Viscoelastic material Kelvin modelDynamic response Elastic modulus and viscosity coefficient

Recent advances in heterogeneous hydrosilylation of unsaturated carbon-carbon bonds

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Chinese Chemical Letters 2024年第6期35卷 71-85页

作者： heng Yang Zhijie Zhou Conghui Tang Feng chen School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The hydrosilylation of unsaturated carbon-carbon bonds is one of the most critical reactions in silicone industrial *** homogeneous Speier's catalyst,Karstedt's catalyst,and other noble metal-based catalysts are widely ***,simplifying the separation of the homogeneous catalyst from reaction products and reducing the high cost of precious metals is still *** review describes the recent development of heterogeneous catalysts for alkene,alkyne,and allene hydrosilylations,which can effectively solve problems in homogeneous hydrosilylation.

关键词： Hydrosilylation Heterogeneous catalysis Alkenes Alkynes Silanes

Self-Assembled Protein Hybrid Nanofibrils for Photosynthetic Hydrogen Evolution

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CCS Chemistry 2024年第3期6卷 812-823页

作者： Weijian chen Xiantao Hu Andi Hu Luyang Ji Yiming Huang Hao heng Fude Feng shu Wang Department of Polymer Science and Engineering School of Chemistry and Chemical EngineeringNanjing UniversityJiangsuNanjing 210023 Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic SolidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190

In artificial photosynthesis systems,synthetic diiron complexes are popular[FeFe]-hydrogenase mimics,which are attractive for the fabrication of photocatalyst-protein hybrid structures to amplify hydrogen(H2)generation ***,constructing a highly bionic and efficient catalytic hybrid system is a major ***,we designed an ideal hybrid nanofibrils system that incorporates the crucial components:(1)a[FeFe]-H2ase mimic,which has a three-arm architecture(named triFeFe)for more interaction sites and higher catalytic activity and(2)uniform hybrid nanofibrils as the biological environment in which cysteine-catalyst coordination and the hydrogen-bonding network play a vital role in both catalyst binding and hydrogen evolution reaction *** assembled hybrid nanofibrils achieve efficient H2 generation with a turnover number of 2.3×103,outperforming previously reported diiron catalyst-protein hybrid ***,the hybrid nanofibrils work with photosynthetic thylakoids to produce H2,without extra photosensitizers or electron shuttle proteins,which advances the bioengineering of living systems for solar-driven biofuel production.

关键词： hybrid photocatalyst in situ assembly amyloid fibrils photosynthetic hydrogen evolution thylakoid

Insights into the electron transfer mechanisms of peroxydisulfate activation by modified metal-free acetylene black for degradation of sulfisoxazole

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Chinese Chemical Letters 2024年第8期35卷 349-356页

作者： Chunxiu Yu Zelin Wu Hongle Shi Lingyun Gu Kexin chen Chuan-shu He Yang Liu heng Zhang Peng Zhou Zhaokun Xiong Bo Lai State Key Laboratory of Hydraulics and Mountain River Engineering College of Architecture and EnvironmentSichuan UniversityChengdu 610065China Sichuan Academy of Eco-Environmental Sciences Chengdu 610041China Sino-German Centre for Water and Health Research Sichuan UniversityChengdu 610065China

Herein,a modified metal-free acetylene black(MMF-AB)catalyst was synthesized by a simple solvothermal-calcination method and designed successfully to activate peroxodisulfate(PDS)for the degradation of sulfisoxazole(SIZ).Due to the doping of N,S and O metal-free elements,the modified catalyst showed excellent catalytic performance with 100%SIZ removal within 30 *** first-order reaction rate constants(evaluating catalytic efficiencies and activity)of MMF-AB(kobs=0.105 min^(−1))was 3 times higher than pure-AB(k_(obs)=0.029 min^(−1)).Interestingly,it was demonstrated that the reaction sys-tem is based on the transfer of electrons from SIZ to PDS to realize an electron-transfer-based mechanism by the evidence of premixing,electron paramagnetic resonance(EPR)spectroscopy,salt-bridge experi-ments and electrochemical *** introduction of recyclable filtration device solved the secondary pollution caused by the dispersion of the powdered catalyst in the treated water,which further proved the practicality and superiority of the MMF-AB catalyst.

关键词： Peroxydisulfate Sulfisoxazole Acetylene black Electrochemical Electron transfer

Efficient reduction and adsorption of Cr(Ⅵ)using FeCl_(3)-modified biochar:Synergistic roles of persistent free radicals and Fe(Ⅱ)

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Journal of Environmental Sciences 2024年第3期137卷 626-638页

作者： shujie Hu Chengshuai Liu Hongling Bu Manjia chen Ying-heng Fei National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and ManagementInstitute of Eco-environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou 510650China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of ScienceGuiyang 550081China School of Environment Science and Engineering Guangzhou UniversityGuangzhou 510006China College of Resources and Environment Chongqing SchoolUniversity of Chinese Academy of SciencesChongqing 400714China School of Environmental Science and Engineering Guangdong University of TechnologyGuangzhou 510006China

Transition metal iron and persistent free radicals(PFRs)both affect the redox properties of biochar,but the electron transfer relationship between them and the coupling reduction mechanism of Cr(Ⅵ)requires further *** untangle the interplay between iron and PFRs in biochar and the infuences on redox properties,FeCl_(3)-modified rice husk biochar(FBCs)was prepared and its reduction mechanism for Cr(Ⅵ)without light was *** FBCs had higher surface positive charges,oxygen-containing functional groups,and PFRs compared with pristine rice husk biochar(BC).Phenoxyl PFRs with high electrondonating capability formed in *** pronounced electron paramagnetic resonance signals showed that the PFRs preferred to form at lower Fe(Ⅲ)*** a high concentration of Fe(Ⅲ)would be reduced to Fe(Ⅱ)and consumed the formed *** kinetics and X-ray photoelectron spectroscopy analysis indicated that the FBCs effectively enhanced the Cr(Ⅵ)removal efficiency by 1.54-8.20 fold and the Cr(Ⅵ)reduction efficiency by 1.88-9.29 fold compared to those of *** quenching and competitive reductant addition experiments revealed that the higher Cr(Ⅵ)reduction performance of FBCs was mainly attributed to the formed PFRs,which could contribute to~74.0%of Cr(Ⅵ)reduction by direct or indirect electron *** PFRs on FBCs surfaces could promote the Fe(Ⅲ)/Fe(Ⅱ)cycle through single electron transfer and synergistically accelerate~52.3%of Cr(Ⅵ)*** study provides an improved understanding of the reduction mechanism of iron-modified biochar PFRs on Cr(Ⅵ)in environments.

关键词： Biochar Iron-modification Cr(Ⅵ) Electron transfer Reduction mechanism

Mid-infrared Period-Luminosity Relations of Gaia DR3 Long Period Variables

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Research in Astronomy and Astrophysics 2024年第7期24卷 56-70页

作者： Xiaohan chen Xiaodian chen Licai Deng shu Wang Tianlu chen Department of Physics College of ScienceTibet UniversityLhasa 850000China Key Laboratory of Cosmic Rays(Tibet University) Ministry of EducationLhasa 850000China CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of the Chinese Academy of SciencesBeijing 100049China Department of Astronomy China West Normal UniversityNanchong 637009China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China

Long period variable(LPV)stars are very promising distance indicators in the infrared *** selected asymptotic giant branch(AGB)stars in the Large and Small Magellanic Cloud(LMC and SMC)from the Gaia Data Release 3 LPV catalog,and classified them into oxygen-rich(O-rich)and carbon-rich(C-rich)AGB *** the Wide-field Infrared Survey Explorer database,we determined the W1-and W2-band period-luminosity relations(PLRs)for each pulsation-mode sequence of AGB *** dispersion of the PLRs of O-rich AGB stars in sequences C'and C is relatively small,around 0.14 *** PLRs of LMC and SMC are consistent in each *** the W2 band,the PLR of large-amplitude C-rich AGB stars is steeper than that of small-amplitude C-rich AGB stars,due to their more circumstellar *** two methods,we find that some PLR sequences of O-rich AGB stars in the LMC are dependent on *** coefficients of the metallicity effect areβ=-0.533±0.213 mag dex~1andβ=-0.767±0.158 mag dex~1for sequence C in W1 and W2 bands,*** significance of the metallicity effect in W1 band for the four sequences is 2.2-3.5σ.Both of these imply that distance measurements using O-rich Mira may need to take the metallicity effect into account.

关键词： stars variables general-stars distances-infrared stars

Thermodynamic and Economic Analysis of a Conceptual System Combining Sludge Gasification,SOFC,Supercritical CO_(2)Cycle,and Organic Rankine Cycle

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Journal of Thermal Science 2024年第4期33卷 1491-1508页

作者： LV Jiayang WANG Chizhong chen heng PAN Peiyuan XU Gang ZHANG Guoqiang School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China

In order to reduce the environmental impact of conventional sludge treatment methods and to utilize the energy in sludge more effectively,a coupled system based on sewage sludge gasifier(SSG),solid oxide fuel cells(SOFC),supercritical CO_(2)cycle(S-CO_(2)),and organic Rankine cycle(ORC)is *** clean syngas obtained from sludge gasification is mixed with CH4 and then first utilized by the fuel *** exhaust gas from the fuel cell is fully combusted in the afterburning chamber and then enters the bottom cycle system consisting of S-CO_(2)&ORC to generate *** understand the performance of the system,thermodynamic and economic analyses were conducted to examine the project's *** thermodynamics as well as the economics of the coupled system were analyzed to arrive at the following conclusions,the power production of the system is 37.34 MW;the exergy efficiency is 55.62%,and the net electrical efficiency is 61.48%.The main exergy destruction is the gasifier and SOFC,accounting for 62.45%of the total exergy *** takes only6.13 years to repay the construction investment in the novel system,and the project obtains a NPV of 17723820USD during 20 years *** above findings indicate that the new coupled system has a better performance in terms of energy utilization and economy.

关键词： sewage sludge gasifier SOFC supercritical CO_(2)cycle organic Rankine cycle multi-system coupling