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Reconstructing forest and grassland cover changes in China over the past millennium

Science China Earth Sciences 2025年第1期68卷 94-110页

作者： fanneng HE fan YANG Yafei WANG Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Key Research Institute of Yellow River Civilization and Sustainable Development Henan University University of Chinese Academy of Sciences

Historical forest and grassland cover changes not only are critical indicators for quantifying ecological and environmental change processes but also serve as fundamental data for long-term climate change simulations and terrestrial ecosystem carbon emission assessments. However, because of limitations in historical data, quantitative estimations and spatially gridded reconstructions of these changes remain challenging, necessitating further methodological exploration. This study focused on China's present-day land area over the past millennium, objectively capturing the characteristics and drivers of forest and grassland cover changes. On this basis, using the forest transition theory and the space-for-time substitution method, we depicted the historical deforestation process as an inverted “S” curve and developed a model to reconstruct historical forest area changes based on the functional relationship between the forest area and population size dynamics. Subsequently, a gridded forest allocation model was established on the basis of deforestation tendencies. For the grassland cover, we implemented regionspecific methods, such as the cropland area deduction method and the habitat constraint method, to quantitatively reconstruct historical changes. Consequently, we obtained provincial forest and grassland area changes over the past millennium and mapped 10-km-resolution gridded data of forest and grassland cover. The results indicated the following.(1) The methods developed using population data as a proxy objectively reproduced the spatiotemporal evolution of forest and grassland cover in China over the past millennium. These feasible methods offer a novel pathway for the quantitative reconstruction of historical forest and grassland cover changes.(2) The data indicated that China's forest area generally decreased over the past millennium, characterized by a “decrease-then-increase” pattern. The forest area experienced three distinct phases: a slow decline(AD 1000

关键词： Land use and land cover change Forest Grassland Quantitative reconstruction Gridded reconstruction China historical period

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Optimizing hardware-software co-design based on non-ideality in memristor crossbars for in-memory computing

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Science China(Information Sciences) 2025年

作者： Pinfeng jiang Danzhe SONG Menghua HUANG fan YANG Letian WANG Pan LIU Xiangshui MIAO Xingsheng WANG School of Integrated Circuits Huazhong University of Science and Technology Hubei Yangtze Memory Labs

The memristor crossbar, with its exceptionally high storage density and parallelism, enables efficient vector matrix multiplication (VMM), significantly improving data throughput and computational efficiency. However, its analog computing is vulnerable to issues like IR-drop, device-to-device (D2D) variation, and stuck-at-fault (SAF), leading to a substantial decrease in the inference accuracy of neural networks deployed on crossbars. This work presents a hardware-software co-design approach tailored to deal with memristor crossbar non-ideality. We introduce an end-to-end functional array simulator (FAST) for precise and ultra fast end-to-end training, mapping, and evaluation of neural networks on the memristor crossbar. Utilizing the sparsity of the memristor crossbar coefficient matrix, it achieves simulation with low storage and computational resource requirements,dynamically selecting the optimal solution to complete the process. It can also precisely simulate the impact of non-ideal effects such as IR-drop, retention, variation, SAF, and AD/DA precision. Using FAST, we assess memristor crossbar matrix operations under non-ideal conditions, identifying the max throughput and the most energy-efficient crossbar configurations. Additionally,we propose a comparator-based activation function modulation (CAFM) scheme and its corresponding hardware architecture with programmable activation function circuits to address the IR-drop issue, enabling low power and area overheads, resulting in the recovery of neural network accuracy by 54%or more. This is validated within FAST, demonstrating the success of our hardware-software optimization co-design.

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金钗石斛提取物对慢性不可预见应激模型小鼠的抗抑郁作用

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生理学报 2017年第2期69卷 159-166页

作者：姜宁范琳犀杨玉洁刘新民林海英高莉王琼西南医科大学医学基础研究中心/药学院泸州646000 中国医学科学院北京协和医学院药用植物研究所北京100193 新疆维吾尔自治区维吾尔医药研究所乌鲁木齐830049

为了探讨金钗石斛提取物对慢性不可预见应激模型小鼠的抗抑郁作用,将BALB/c小鼠分为6组,即正常组、模型组、阳性药组(帕罗西汀),金钗石斛低(50 mg/kg)、中(100 mg/kg)、高(200 mg/kg)剂量组,灌胃给药两周后,除正常组外,其他组给予慢性... 详细信息

为了探讨金钗石斛提取物对慢性不可预见应激模型小鼠的抗抑郁作用,将BALB/c小鼠分为6组,即正常组、模型组、阳性药组(帕罗西汀),金钗石斛低(50 mg/kg)、中(100 mg/kg)、高(200 mg/kg)剂量组,灌胃给药两周后,除正常组外,其他组给予慢性不可预见性应激造模35天。造模结束后,通过糖水偏爱、新奇抑制摄食、强迫游泳实验和悬尾实验检测其行为学改变,采用LC-MS/MS测定各组小鼠应激后海马及皮层单胺类神经递质包括多巴胺(dopamine,DA)和5-羟色胺(5-hydroxytryptamine,5-HT)的含量改变。结果显示,与正常组相比,模型组小鼠糖水偏爱指数下降(P0.05)。与正常组相比,模型组小鼠皮层和海马中的DA和5-HT含量明显减少(P<0.05);帕罗西汀能使模型小鼠海马和皮层DA、海马5-HT含量明显增加(P<0.05);金钗石斛低、高剂量组皮层DA含量与模型组相比显著性升高(P<0.05),金钗石斛中、高剂量组海马DA含量与模型组相比显著性升高(P<0.05);金钗石斛高剂量组皮层和海马5-HT含量显著高于模型组(P<0.05),但金钗石斛中剂量组仅海马5-HT含量显著高于模型组(P<0.01)。以上结果提示,慢性不可预见应激可导致小鼠的类抑郁样行为出现,而金钗石斛提取物能有效改善慢性不可预见应激模型动物的抑郁样行为学表现,并提高小鼠脑内的DA和5-HT水平。

关键词：金钗石斛抑郁慢性不可预见应激行为学检测

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Dynamic behaviors of graphene platelets-reinforced metal foam piezoelectric beams with velocity feedback control

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 63-80页

作者： Jie CHEN Xinyue ZHANG Mingyang fan School of Mathematics Statistics and Mechanics Beijing University of Technology College of Mechanical & Energy Engineering Beijing University of Technology

Graphene platelets(GPLs)-reinforced metal foam structures enhance the mechanical properties while maintaining the lightweight characteristics of metal foams. Further bonding piezoelectric actuator and sensor layers on the surfaces of GPLs-reinforced metal foam beams enables active vibration control, greatly expanding their applications in the aerospace industry. For the first time, this paper investigates the vibration characteristics and active vibration control of GPLs-reinforced metal foam beams with surfacebonded piezoelectric layers. The constant velocity feedback scheme is used to design the closed-loop controller including piezoelectric actuators and sensors. The effects of the GPLs on the linear and nonlinear free vibrations of the beams are numerically *** Newmark-β method combined with Newton's iteration technique is used to calculate the nonlinear responses of the beams under different load forms including harmonic loads,impact loads, and moving loads. Additionally, special attention is given to the vibration reduction performance of the velocity feedback control on the responses of the beam.

关键词： Piezoelectric actuators

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Automatic and Rapid Throughflow-Based Optimal Design Method for Multi-Stage Axial-Flow Compressors

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Journal of Thermal Science 2025年第1期34卷 77-91页

作者： LEI fan ZHANG Xiawen JU Yaping ZHANG Chuhua Department of Fluid Machinery and Engineering School of Energy and Power EngineeringXi'an Jiaotong University Production and Environmental Department China Huaneng Group.Co.Ltd. State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong University

Throughflow design has the advantages of less time consumption and large optimization space,and thus is the corner stone of advanced design system of multi-stage axial-flow *** majority of relevant studies were limited to the throughflow inverse designs,and quite few works have been till now devoted to the throughflow optimal *** this work,an automatic and rapid throughflow-based optimal design method is proposed for axial-flow compressors in which a throughflow inverse design solver is embedded in optimal genetic algorithm to improve the design efficiency of axial-flow *** types of design parameters in the throughflow inverse design of axial-flow compressors,i.e.,swirl and shroud curve,are simultaneously used to optimize both the blade shape and flow *** proposed method is validated by the redesign optimization of the benchmark axial-flow compressor NASA Stage 35,and the CFD predictions show that the throughflow-based optimization leads to 1.18% efficiency benefit at design *** proposed method is then utilized to the two-dimensional throughflow optimal design of a large-scale 6.5-stage axial-flow industrial *** optimal design results are confirmed by CFD predictions,indicating that the proposed method can effectively improve the design adiabatic efficiency of the compressors by 1.09% within a few minutes on desk-top *** throughflow design implications are also obtained for advanced axial-flow industrial *** work could enhance the capability of throughflow design method and has engineering application value to explore the throughflow optimization space of multi-stage axial-flow compressors.

关键词： NASA

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Effect of a Carbon Fibre-steel Fibre-graphite Conductive Filler on the Electrothermal Properties of Cementitious Materials

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 141-151页

作者： fan Yanan WEI Hong ZHENG Hongyong DU Hongxiu Department of Architecture and Environmental Engineering Taiyuan UniversityTaiyuan 030032China College of Civil Engineering Taiyuan University of TechnologyTaiyuan 030032China

Carbon fibre,steel fibre and graphite were used as conductive fillers to prepare cementitious materials with excellent electrothermal *** electrically conductive cementitious materials with different volume dosages were analysed through compressive and flexural strength,electrochemical impedance spectroscopy and temperature rise *** equivalent circuit model was established to study the electrically conductive heat generation mechanism in the electrically conductive cementitious *** results indicate that the mechanical properties of cementitious composite materials with a ternary conductive phase are better than those of pristine cementitious materials because the fibrous filler improves their mechanical ***,the incorporation of graphite in the material reduces its *** fibrous and point-like conductive phase materials into the cementitious material enhances the overall conductive pathway and considerably reduces the electrical resistance of the cementitious material,enhancing its conductive *** volume ratios of carbon fibre,steel fibre and graphite that achieve an optimal complex doping in the cementitious material were 0.35%,0.6%and 6%,*** was determined using the mutation point of each circuit element parameter as the percolation *** addition,at a certain safety voltage,there is a uniform change between the internal and surface temperatures of the conductive cementitious material,and the heating effect in this materialis is considerably better than that in the pristine cementitious material.

关键词： cementitious composites conductive fillers electrothermal properties electrochemical impedance spectroscopy

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Endoscopy-assisted lightweight diagnosis system based on transformers for colon polyp detection

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Optoelectronics Letters 2025年第1期21卷 57-64页

作者： fan Weiming YU Jiahui JU Zhaojie School of Automation and Electrical Engineering Shenyang Ligong University Department of Biomedical Engineering Zhejiang University School of Computing University of Portsmouth

The integration of endoscopy has significantly propelled the diagnosis and treatment of gastrointestinal diseases, with colonoscopy establishing itself as the primary method for early diagnosis and preventive care in colorectal cancer(CRC). Although deep learning holds promise in mitigating missed polyp rates, modern endoscopy examinations pose additional challenges, such as image blurring and atomizing. This study explores lightweight yet powerful attention mechanisms, introducing the spatial-channel transformer(SCT), an innovative approach that leverages spatial channel relationships for attention weight calculation. The method utilizes rotation operations for inter-dimensional dependencies, followed by residual transformation, encoding inter-channel and spatial information with minimal computational overhead. Extensive experiments on the CVC-Clinic DB polyp detection dataset, addressing endoscopy pitfalls, underscore the superiority of our SCT over other state-of-the-art methods. The proposed model maintains high performance, even in challenging scenarios.

关键词： Endoscopy

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Macro-mechanics and Microstructure of Nanomaterial-modified Geopolymer Concrete: A Comprehensive Review

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 204-214页

作者： WANG Tao fan Xiangqian GAO Changsheng QU Chiyu The National Key Laboratory of Water Disaster Prevention Nanjing Hydraulic Research InstituteNanjing 210024China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China School of Water Conservancy and Transportation Zhengzhou UniversityZhengzhou 450001China

We have described in detail the effects of nano-SiO_(2),nano-CaCO_(3),carbon nanotubes,and nano-Al_(2)O_(3) on geopolymer concrete from the perspectives of macro mechanics and *** existing research results show that the mechanism of nano-materials on geopolymer concrete mainly includes the filling effect,nucleation effect,and bridging effect,the appropriate amount of nano-materials can be used as fillers to reduce the porosity of geopolymer concrete,and can also react with Ca(OH)2 to produce C-S-H gel,thereby improving the mechanical properties of geopolymer *** optimum content of nano-SiO_(2) is between 1.0%and 2.0%.The optimum content of nano-CaCO_(3) is between 2.0%and 3.0%.The optimum content of carbon nanotubes is between 0.1%and 0.2%.The optimum content of nano-Al_(2)O_(3) is between 1.0%and 2.0%.The main problems existing in the research and application of nanomaterial-modified geopolymer concrete are summarized,which lays a foundation for the further application of nanomaterial in geopolymer concrete.

关键词： nanomaterials low carbon geopolymer concrete macro-mechanics microstructure

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Identification of a dual functional betulinic acid analog for the treatment of osteoarthritis by phenotypic screening

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Science China Life Sciences 2025年第1期68卷 300-302页

作者： Ze-Min lin Mai Xiang Wen-Hui Wei Shu-Hui fan Li Chen Jie Wang Xiao-Qian Yang Chun-Hao Yang Shi-Jun He Jian-Ping Zuo Laboratory of Immunopharmacology State Key Laboratory of Drug ResearchShanghai Institute of Materia MedicaChinese Academy of Sciences School of Pharmacy University of Chinese Academy of Sciences School of Pharmacy Nanjing University of Chinese Medicine State Key Laboratory of Drug Research Department of Medicinal ChemistryShanghai Institute of Materia MedicaChinese Academy of Sciences Innovation Research Institute of Traditional Chinese Medicine Shanghai University of Traditional Chinese Medicine Experiment Center for Science and Technology Shanghai University of Traditional Chinese Medicine

Dear Editor, Phenotypic drug discovery, which observes compound effects on physiology,has given way to targeting specific molecules, but has revived by using modern methods to find drugs based on therapeutic outcomes in disease models(Vincent et al., 2022). Osteoarthritis(OA) is a prevalent chronic joint disorder, primarily affecting knee joints, with osteoclast activation due to low-grade inflammation resulting in increased bone resorption and structural changes in the joint(Katz et al.,2021).

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Experimental Study on Geometry Characteristics of Turbulent Premixed Flames for Natural Gas/Air Mixtures

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Journal of Thermal Science 2025年第1期34卷 268-282页

作者： ZHENG Weilin WANG Qijiao XIAO Huahua CHEN Xiaoxiao XIE fan ZENG Wen Liaoning Key Lab of Advanced Test Technology for Aerospace Propulsion System Shenyang Aerospace University State Key Laboratory of Fire Science University of science and Technology of China AVIC Shenyang Aircraft Design and Research Institute

In this study,focusing on the geometry characteristics of spherical expanding flame,the turbulent premixed flames of natural gas/air mixtures were investigated in a fan-stirred turbulent *** effects of initial temperature（T=300-400 K）,initial pressure（P=0.1-0.3 MPa）,turbulence intensity（u'=1.0-2.7 m/s）,oxygen volumetric percentage(φ（O2）=15%-21%) and carbon dioxide volumetric percentage(φ（CO2）=0-20%)were delved *** flame profile under the Cartesian coordinate system was derived from the schlieren images taken by the high-speed ***,from both macroscopic and microscopic perspectives,the influence of experimental conditions on the flame geometry characteristics was explored through flame front extraction,wavelet decomposition and network *** results demonstrate that for significant flame wrinkling,changes in species concentrations and turbulence intensity have more pronounced effects on the flame wrinkling *** wrinkling of the flame front maintains a certain degree of similarity,as evidenced by the locally concentrated distribution of the angles of the maximum fluctuation *** disturbance energy under large-scale（D6-D8） disturbances exhibits relatively high values with a similar trend,exerting a significant impact on the geometry characteristics of the flame *** peaks of correlation degree are scattered either with the decomposition scale or the development of flame radius,indicating no linear correlation between different detail ***,the probability distribution of node degrees in key wrinkled regions exhibits different trends with that of large-scale wrinkling and disturbance energy,especially with changes in initial *** occurs because the number of key wrinkles varies based on the perturbation's strength or the region's ***,an increase in the fluctuation frequency of the flame's local radius may not necessarily lead to an increase in the number of key folded regions.

关键词： fan-stirred turbulent combustor geometry characteristics large-scale wrinkling network topology wavelet decomposition

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