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How forest age impacts on net primary productivity: Insights from future multi-scenarios

Forest Ecosystems 2024年第5期11卷 708-719页

作者： lei Tian Yu Tao Simms Joanna Annikki mäakelä mingyang Li Co-Innovation Center for Sustainable Forestry in Southern China Nanjing Forestry UniversityNanjingChina Faculty of Agriculture and Forestry University of HelsinkiHelsinkiFinland

Forest net primary productivity(NPP)constitutes a key flux within the terrestrial ecosystem carbon cycle and serves as a significant indicator of the forests carbon sequestration capacity,which is closely related to forest *** its significance,the impact of forest age on NPP is often ignored in future NPP ***,we mapped forest age in Hunan Province at a 30-m resolution utilizing a combination of Landsat time series stack(LTSS),national forest inventory(NFI)data,and the relationships between height and ***,NPP was derived from NFI data and the relationships between NPP and age was built for various forest *** forest NPP was predicted based on the NPP-age relationships under three future scenarios,assessing the impact of forest age on *** findings reveal substantial variations in forest NPP in Hunan Province under three future scenarios:under the age-only scenario,NPP peaks in 2041(133.56TgC·yr^(−1)),while NPP peaks three years later in 2044(141.14TgC·yr^(−1))under the natural development *** maximum afforestation scenario exhibits the most rapid increase in NPP,with peaking in 2049(197.95TgC·yr^(−1)).However,with the aging of the forest,NPP is projected to then decrease by 7.54%,6.07%,and 7.47%in 2060,and 20.05%,19.74%,and 28.38%in 2100,respectively,compared to their peaks under the three *** indicates that forest NPP will continue to decline *** the age structure of forests through selective logging,afforestation and reforestation,and encouraging natural regeneration after disturbance could mitigate this declining trend in forest NPP,but implications of these measures on the full forest carbon balance remain to be *** from the future multi-scenarios are expected to provide data to support sustainable forest management and national policy development,which will inform the achievement of carbon neutrality goals by 2060.

关键词： Net primary productivity Forest age NPP-Age relationships NPP projections Afforestation

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Reducing Social media Attention Inequality in Disasters: The Role of Official media During Rainstorm Disasters in China

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International Journal of Disaster Risk Science 2024年第3期15卷 388-403页

作者： Longfei Zheng lei Chen Fenjie Long Jianing Liu lei Li School of Geography Faculty of Geographical Science Beijing Normal University Hang Lung Center for Real Estate and Department of Construction management Tsinghua University

Unequal social media attention can lead to potentially uneven distribution of disaster-relief funds, resulting in long-term inequality among regions after disasters. This study aimed to measure inequalities in social media attention to regions during disasters and explore the role of official media in reducing such inequality. This is performed by employing social media,official media, and official aggregated statistics regarding China's rainstorm disasters. Through a set of panel-data regressions and robustness tests, three main conclusions were drawn:(1) There were inequalities among regions regarding social media attention they received during rainstorm disasters. For disasters of the same magnitude, regions with low economic outcome per capita received less attention on social media.(2) Official media can reduce inequality in social media attention during disasters. Official media statements can encourage netizens to pay attention to disaster-stricken areas, and especially the overlooked underdeveloped areas.(3) Of all the measures taken by official media, timely, accurate, and open disclosure of disaster occurrences proved to be the most potent means of leveling the playing field in terms of social media attention;contrarily, promotional or booster-type messages proved futile in this regard. These findings revealed the vulnerabilities within social media landscapes that aff ect disaster relief response, shedding light on the role of official guidance in mitigating inequalities in social media attention during such crises. Our study advises social media stakeholders and policymakers on formulating more equitable crisis communication strategies to bridge the gap in social media attention and foster a more balanced and just relief process.

关键词： China, inequality of attention Official media Rainstorm disasters Situational crisis communication theory Social media

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Optical modeling of Sea Salt Aerosols Using in situ measured Size Distributions and the Impact of Larger Size Particles

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Advances in Atmospheric Sciences 2024年第10期41卷 1917-1935页

作者： Wushao LIN lei BI Key Laboratory of Geoscience Big Data and Deep Resource of Zhejiang Province School of Earth SciencesZhejiang UniversityHangzhou 310058China

Sea salt aerosols play a critical role in regulating the global climate through their interactions with solar *** size distribution of these particles is crucial in determining their bulk optical *** this study,we analyzed in situ measured size distributions of sea salt aerosols from four field campaigns and used multi-mode lognormal size distributions to fit the *** employed super-spheroids and coated super-spheroids to account for the particles’non-sphericity,inhomogeneity,and hysteresis effect during the deliquescence and crystallization *** compute the singlescattering properties of sea salt aerosols,we used the state-of-the-art invariant imbedding T-matrix method,which allows us to obtain accurate optical properties for sea salt aerosols with a maximum volume-equivalent diameter of 12μm at a wavelength of 532 *** results demonstrated that the particle models developed in this study were successful in replicating both the measured depolarization and lidar ratios at various relative humidity(RH)***,we observed that large-size particles with diameters larger than 4μm had a substantial impact on the optical properties of sea salt aerosols,which has not been accounted for in previous ***,excluding particles with diameters larger than 4μm led to underestimating the scattering and backscattering coefficients by 27%−38%and 43%−60%,respectively,for the ACE-Asia field ***,the depolarization ratios were underestimated by 0.15 within the 50%−70%RH *** findings emphasize the necessity of considering large particle sizes for optical modeling of sea salt aerosols.

关键词： sea salt aerosol particle size distribution lidar optical property

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Ultrathin and flexible mXene-contained electromagnetic interference shielding composite paper designed with a protective hydrogel film

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Journal of materials Science & Technology 2024年第2期169卷 199-208页

作者： Jiasheng Wei lei Dai Ping He meng Zhu Feng Jiang Zhaoxiang Zhou Guiqiang Fei Tingzhou lei College of Bioresources Chemical and materials Engineering Shaanxi University of Science and TechnologyXi’an 710021China Key Laboratory of Eco-Textiles Ministry of EducationJiangnan UniversityWuxi 214122China Zhejiang Shunpu New material Technology Co. LtdLongyou 324404China College of Chemistry and Chemical Engineering Shaanxi University of Science and TechnologyXi’an 710021China National-Local Joint Engineering Research Center of Biomass Refining and High-Quality Utilization Institute of Urban and Rural MiningChangzhou UniversityChangzhou 213164China

mXene-contained paper is a good choice to design ultrathin and flexible electromagnetic interference(EmI)shielding ***,the deficiencies in strength and stability of mXene-contained paper impede its practical ***,a composite paper was proposed to address the problems,in which a filter paper was modified with a three-layer structured surface via a facile layer-by-layer coating ***,the TEmPO-oxidized cellulose nanofibers(TOCN)/cationic starch(CS)/mXene gel layer and TOCN/mXene nacre structure layer ensured the good EmI shielding and mechanical performances of the composite paper,while the uppermost TOCN/CS hydrogel film layer mainly protected *** composite paper achieved an EmI SE of 40.3 dB at a thickness of merely 0.1894 mm(SE/t value of ca.212.8 dB mm^(−1),SSE/t values of ca.13216 dB cm 2 g^(−1))and the total mXene dosage was 20 g m^(−2).Its tensile strength could be up to 11.7 mPa while the original filter paper was 6.4 *** pieces of this composite papers could be easily packed together to attain an EmI SE of nearly 70 ***,the hydrogel film layer efficiently protected the mXene and maintained the EmI shielding performance of the composite paper when immersed in different liquids including water,HCl(1 m)and ethanol,due to the dense and compact structure of hydrogel film *** work provides a practical way to develop ultrathin,flexible and durable EmI shielding materials.

关键词： mXene Electromagnetic interference shielding Nanocellulose Hydrogel

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Coseismic Coulomb stress changes induced by a 2020-2021 m_(W)>7.0 Alaska earthquake sequence in and around the Shumagin gap and its influence on the Alaska-Aleutian subduction interface

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Geodesy and Geodynamics 2024年第1期15卷 1-12页

作者： lei Yang Jianjun Wang Caijun Xu School of Geodesy and Geomatics Wuhan UniversityWuhan 430079China Collaborative Innovation Center of Geospatial Technology Wuhan 430079China Key Laboratory of Geospace Environment and Geodesy Ministry of EducationWuhan UniversityWuhan 430079China

Three m_(W)>7.0 earthquakes in 2020-2021 occurred in the Shumagin seismic gap and its adjacent area of the Alaska-Aleutian subduction zone,including the mw7.8 Simeonof thrust earthquake on July 22,2020,the m_(W)7.6 Sand Point strike-slip earthquake on October 19,2020,and the m_(W)8.2 Chignik thrust earthquake on July 29,*** spatial and temporal proximity of these three earthquakes prompts us to probe stress-triggering effects among *** we examine the coseismic Coulomb stress change imparted by the three earthquakes and their influence on the subduction *** results show that:(1)The Simeonof earthquake has strong loading effects on the subsequent Sand Point and Chignik earthquakes,with the Coulomb stress changes of 3.95 bars and 2.89 bars,*** Coulomb stress change caused by the Sand Point earthquake at the hypocenter of the Chignik earthquake is merely around 0.01 bars,suggesting the negligible triggering effect on the latter earthquake;(2)The triggering effects of the Simeonof,Sand Point,and Chignik earthquakes on aftershocks within three months are not well pronounced because of the triggering rates of 38%,14%,and 43%*** factors may have played an important role in promoting the occurrence of these aftershocks,such as the roughness of the subduction interface,the complicated velocity structure of the lithosphere,and the heterogeneous prestress therein;(3)The three earthquakes caused remarkable coseismic Coulomb stress changes at the subduction interface nearby these mainshocks,with an average Coulomb stress change of 3.2 bars in the shallow region directly inwards the trench.

关键词： The 2020-2021 Alaska earthquake sequence Coseismic Coulomb stress change mainshock-aftershock triggering The Alaska-Aleutian subduction interface The Shumagin gap

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Utilizing quantum coherence in Cs Rydberg atoms for high-sensitivity room-temperature terahertz detection: a theoretical exploration

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Photonics Research 2024年第7期12卷 1583-1592页

作者： lei HOU JUNNAN WANG QIHUI HE SUGUO CHEN lei YANG SUNCHAO HUANG WEI SHI Department of Physics Xi’an University of TechnologyXi’an 710048China School of Electrical Engineering Xi’an University of TechnologyXi’an 710048China School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore 610101Singapore

In recent years,terahertz (THz) technology has made significant progress in numerous applications;however,the highly sensitive,room-temperature THz detectors are still rare,which is one of the bottlenecks in THz *** this paper,we proposed a room-temperature electrometry method for THz detection by laser spectroscopy of cesium(^(133)Cs) Rydberg atoms,and conducted a comprehensive investigation of the five-level system involving electromagnetically induced transparency (EIT),electromagnetically induced absorption (EIA),and Autler–Townes (AT) splitting in^(133)Cs *** solving the Lindblad master equation,we found that the influence of the THz electric field,probe laser,dressing laser,and Rydberg laser on the ground state atomic population as well as the coherence between the ground state and the Rydberg state,plays a crucial role in the transformation and amplitude of the EIT and EIA *** and the atomic vapor cell’s dimensions affect the number of^(133)Cs atoms involved in the detection,and ultimately determine the *** predicted the proposed quantum coherence THz detection method has a remarkable sensitivity of as low as 10^(-9)V m^(-1)Hz^(-1/2).This research offers a valuable theoretical basis for implementing and optimizing quantum coherence effects based on Rydberg atoms for THz wave detection with high sensitivity and room-temperature operation.

关键词： quantum Rydberg dimensions

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Core-shell mesoporous carbon hollow spheres as Se hosts for advanced Al-Se batteries

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International Journal of minerals,metallurgy and materials 2024年第5期31卷 899-906页

作者： Haiping lei Tianwei Wei Jiguo Tu Shuqiang Jiao State Key Laboratory of Advanced metallurgy University of Science and Technology BeijingBeijing 100083China School of metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

Incorporating a selenium(Se)positive electrode into aluminum(Al)-ion batteries is an effective strategy for improving the overall battery ***,the cycling stability of Se positive electrodes has challenges due to the dissolution of intermediate reaction *** this work,we aim to harness the advantages of Se while reducing its limitations by preparing a core-shell mesoporous carbon hollow sphere with a titanium nitride(C@TiN)host to load 63.9wt%Se as the positive electrode material for Al-Se *** the physical and chemical confinement offered by the hollow mesoporous carbon and TiN,the obtained core-shell mesoporous carbon hollow spheres coated with Se(Se@C@TiN)display superior utilization of the active material and remarkable cycling *** a result,Al-Se batteries equipped with the as-prepared Se@C@TiN composite positive electrodes show an initial discharge specific capacity of 377 mAh·g^(-1)at a current density of 1000 mA·g^(-1)while maintaining a discharge specific capacity of 86.0 mAh·g^(-1)over 200 *** improved cycling performance is ascribed to the high electrical conductivity of the core-shell mesoporous carbon hollow spheres and the unique three-dimensional hierarchical architecture of Se@C@TiN.

关键词： aluminum-selenium batteries intermediate products core-shell mesoporous carbon hollow sphere cycling performance

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modulation mechanism of electron energy dissipation on superlubricity based on fluorinated 2D ZIFs

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Nano Research 2024年第4期17卷 3198-3209页

作者： Yuxin Li lei Liu Kunpeng Wang Yuhong Liu State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China School of mechatronic Engineering Shanghai UniversityShanghai 200444China

Electron energy dissipation is an important energy dissipation pathway that cannot be ignored in friction ***-dimensional zeolite imidazole frameworks(2D ZIFs)and fluorine doping strategies give 2D Zn-ZIF and 2D Co-ZIF unique electrical properties,making them ideal materials for studying electron energy dissipation *** this paper,based on the superlubricity modulation of 2D fluoridated ZIFs,the optimal tribological properties are obtained on the 2D F-Co-ZIF surface,with the friction coefficient as low as *** experiments,density functional theory(DFT)simulation,and fluorescence detection are used to explain the mechanism of fluorine doping regulation of tribological properties from the two stages,namely energy transfer and energy ***,the energy will transfer into the friction system through the generation of electron–hole pairs under an external excitation,and release by radiation and non-radiation energy dissipation *** reduces energy transfer by altering the electronic properties and band structures of ZIFs,and slows down the charge transfer by enhancing the shielding efficiency,thus slowing the non-radiative energy dissipation rate during the energy release *** insights not only help us better understand the role of fluorine doping in improving tribological properties,but also provide a new way to further explore the electron energy dissipation pathway during friction.

关键词： superlubricity electron energy dissipation modulation two-dimensional zeolite imidazole frameworks(2D ZIFs) fluorination

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Fault diagnosis of HVAC system with imbalanced data using multi-scale convolution composite neural network

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Building Simulation 2024年第3期17卷 371-386页

作者： Rouhui Wu Yizhu Ren mengying Tan lei Nie School of mechanical Engineering Hubei University of TechnologyWuhan430068China Industrial Research Institute of Xiangyang Hubei University of Technology Xiangyang441100China

Accurate fault diagnosis of heating,ventilation,and air conditioning(HVAC)systems is of significant importance for maintaining normal operation,reducing energy consumption,and minimizing maintenance ***,in practical applications,it is challenging to obtain sufficient fault data for HVAC systems,leading to imbalanced data,where the number of fault samples is much smaller than that of normal ***,most existing HVAC system fault diagnosis methods heavily rely on balanced training sets to achieve high fault diagnosis ***,to address this issue,a composite neural network fault diagnosis model is proposed,which combines SmOTETomek,multi-scale one-dimensional convolutional neural networks(m1DCNN),and support vector machine(SVm).This method first utilizes SmOTETomek to augment the minority class samples in the imbalanced dataset,achieving a balanced number of faulty and normal ***,it employs the m1DCNN model to extract feature information from the augmented ***,it replaces the original Softmax classifier with an SVm classifier for classification,thus enhancing the fault diagnosis *** the SmOTETomek-m1DCNN-SVm method,we conducted fault diagnosis validation on both the ASHRAE RP-1043 dataset and experimental dataset with an imbalance ratio of 1:*** results demonstrate the superiority of this approach,providing a novel and promising solution for intelligent building management,with accuracy and F1 scores of 98.45%and 100%for the RP-1043 dataset and experimental dataset,respectively.

关键词： fault diagnosis chiller imbalanced data SmOTETomek multi-scale neural networks

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Boron nitride silicone rubber composite foam with low dielectric and high thermal conductivity

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Chinese Journal of Chemical Engineering 2024年第4期68卷 224-230页

作者： Shuilai Qiu Hang Wu Fukai Chu lei Song College of Safety and Ocean Engineering China University of Petroleum-BeijingBeijing 102249China State Key Laboratory of Fire Science University of Science and Technology of ChinaHefei 230026China

Silicone rubber(SR)is widely used in the field of electronic packaging because of its low dielectric *** this work,the porosity of the SR was improved,and the dielectric constant of the SR foam was reduced by adding expanded microspheres(Em).Then,the thermal conductivity of the system was improved by combining the modified boron nitride(f-BN).The results showed that after the f-BN was added,the dielectric constant and dielectric loss were much lower than those of pure ***-sized modified boron nitride(f-mBN)improved the dielectric and thermal conductivity of the SR foam better than that of nano-sized modified boron nitride(f-nBN),but f-nBN improved the volume resistivity,tensile strength,and thermal stability of the SR better than *** the mass ratio of f-mBN and fnBN is 2:1,the thermal conductivity of the SR foam reaches the maximum value of 0.808 W·m^(-1)·K^(-1),which is 6.5 times that before the *** heat release rate and fire growth index are the lowest,and the improvement in flame retardancy is mainly attributed to the high thermal stability and physical barrier of f-BN.

关键词： Foam Composites Dielectric properties Thermal conductivity mechanical properties Flame retardant

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